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Dr. C. A. Chant

April.

.4, 1955

r-juiiilcii ;.v Kich.aU A. V!.,^u.r.

With which is incorporated Hardwicke's Science Gossip), and the Ilhistrated Scientific Xe\v5

A Monthlv Record of Science.

CONDITTF.II BY

Wilfred Mark Webb, F.L.S., and E. S. Grew, M.A

Let Knowledge grow troni more to more."

-Teiiiiysoii.

X'ulume XXXIV.

New Series, \"ohnne \'in.

1911.

London :

Knowledge Publishing Company, Limited,
-4i. Bloonisburx' Square, W.C.

9 9/

^

T^fr."f:sp!ece to KNO

I

m a photograph taken at

Yerkes Observatory, September ISth, idOI.

The Nebula in Andromeda.
Printed by the Photo- Printing- Syndicate, with a Rotary Photogravure Machine, on ordinary paper.

Knowledge.

With wiiicli is incorporated Hard\vicl<e's Science Gossip, and tlie Illustrated Scientiiic News.

A Monthly Record of Science.

Conducted by Wilfred Mark Webb, l-.L.S., and E. S. Grew, M.A.

JANUARY, 1911.

A SIMPLE EXPERIMENT ON THE FORMATION OF

DROPS OF LIOUID.

Bv CHAKLi:s K. DARLING. A.R.C.Sc.L, F.I.C.

When a suspended mass of H(iui(l attains a definite
size it becomes too heav\' to be sustained bv the
adhesion of the li(]uid to the surface from which it
hangs, and, consequentl\", a i)orti(>n breaks awaw
resulting in the formation of a spherical droj).
WHien the liquid hangs in air. as in the case of water
on the end of a leaky tap, the drop breaks away ttio
(]uickly to jiermit the process of separation to be
obser\ed by the unaided eve. In order to study
the changes in outline undergone b}- the suspended
liquid, instantaneous photograph\' and rapidh-
intermittent light have been emplo\ed, and ha\'e
succeeded in disclosing the beautiful transition

inches in (Hanieter, is tilled with water to the height
of ahum four and a-half incites, and seventy or eighty
cubic centimetres of commercial aniline are added,
which will sink to the bottom of the vessel. The
temperature of tlie beaker and its contents is now
raised to 75'' or 80° C. b)' means of a burner, when
it will be observed that the aniline will rise to the
surface of the water, from which it will hang in a
mass of curved outline. Almost immediatel}- the
suspended aniline commences to alter in shape ;
and gradually a large (h'op. an iiieh or more in
diameter, detaches itself from the mass and falls
through the water. The formation of this droi)

Tirr

3 4

The forniation of a drop of aniline.

shapes which accompan\' the detachment of the
drop. Either of these methods of observation, how-
ever, demands the use of elaborate instruments, and
it is here proposed to describe an experiment of the
simplest description, which not only enables the
process to be followed easily by the eye, but is unique
in the respect that the formation of the drops is
automatic and continuous. It was arrived at by the
author as the result of a comparative stud\- of the
physical properties of water and other liquids of
approximatelv equal densitw

A glass beaker, about six inches high and four

takes place so slowly, owing to the aniline being
buoved up bv the water beneath, that all the changes
of shape associated with the process may be observed
distinctlv. The appearance presented is well shown
in the accompanying photographs, taken by Mr. B.
Abel, of the Ci"t>- and Guilds Technical College,
Finsburv, with an ordinary hand camera. In
No. 1 the formation is commencing ; No. 2 repre-
sents the stage just preceding the formation of the
neck ; in No. 3 the neck has formed, and in No. 4
the drop has just broken away : No. 5 shows the
flattening of the drop due to the shock of breakage,

KNOWLEDGE.

January. 1911.

and also shows the neck to have taken a cylindrical
form : whilst in No. 6 the distortion of the drop has
proceeded further, and the c\-lindrical neck, being
unstable, is seen "to be breaking up into three
separate portions, each of which forms a sphere.
These photographs, however, do not give such a
complete idea of the process as may be (obtained b\-
watching the experiment, as onh' six detached
stages are represented. \'ariations occur, also, in
the fate of the neck, which sometimes shrinks back
into the mass remaining on the surface: sometimes
breaks off and forms a single sphere, and often
several spheres of varying sizes. The exact method
of taking the photographs \\ ill he explained later.

And now. the detached drop ha\-ing fallen to the
hiittoni of the beaker, comes the sur[)rising part of
the experiment. The fallen drop is seen gradually
to rise to the surface, where it joins the mass from
which it previously broke awa\'. M once another
drop commences to form, and having become detached,
falls and rises in the same manner as the previous
drop. So long as the temperature of the water is
maintained at 70" C or over, this procedure continues
indefinitely. The forces at work on the drop perform
a Sisyphean task.

Here it may be exjilained that the photographs
shown do not represent one and the same drop, but
that a snap-shot was taken at different phases in
the formation of six separate drojjs. The uniformit\-
with which the process is repeated is thus exhibited
in a striking manner, as the photographs might easih'
be taken to represent six stages in tlii_' formation of
a single drop. It may be added that the temperature
should ne\'er exceed 85 ~' C. nor fall lielow 70" C if
photographs are being taken : and that the distorting
effect of the glass beaker may be ox'ercome bv jdacing
it in a rectangular vessel with glass sides, also
(-ontaining hot water. This plan was followed b\-
Mr. Abel in securing the photographs shown : it is
also suitable for the optical projection of the
experiment.

The explanaticjn of the formation of the drops and
their subsequent ascent to the surface is, in the
main, simple. .\niline is a liquid which at low
temjieratures is denser than cold water, but at high
temperatures lighter than hot water, owing to its

higher degree of expansion. If dropped into water
below 60" C. aniline will sink ; but if the temperature
of the water exceed 65" C, the aniline, after becoming
warmed b}' its surroundings, will rise. Hence, in
the experiment under notice, the aniline ascends to
the surface of the water o\\ing to its lesser densit\'.
By spreading out on the surface, however, the
aniline is cooled more than the water beneath, and
soon becomes denser than the water in consequence
of this cooling. The aniline then tends to sink, and
a drop breaks off as shown in the photographs.
By passing through the hot water, however, the
temperature of the detached drop rises, and if the
temperature exceed 65" the drop will again become
lighter than its surroundings and will ascend
to the surface. The success of the experiment
depends upon this remarkably delicate balance
in the temperature-densit\' relations of aniline and
water. It must be stated, however, that aniline is
partially soluble in water, and hence the drop is
falling not through [jure water, but a saturated
solution of aniline in water. Questions with regard
to the surface tensions of the liquids would also have
to be entered into in giving a detailed explanation :
and these apparently minor details probabh- furnish
the reason why certain other liquids, which might be
expected to behave in the same manner if substituted
for aniline in the experiment, fail to do so. So far
as investigations ha\e been conducted, no other
liquid has been made to operate automaticalK' in
producing and reproducing the drop.

One other feature of the experiment is deserving
of notice. It ma}' be made to represent the principle
of elementar\" heat engines. The lower part of the
water ser\-es as the source of heat : the atmosphere
above the surface acts as the refrigerator to which
the rejected heat is given ; and work could be done
b\' the mo\'ing drop. It would not be difficult to
construct an indicator diagram for this rudi-
mentary heat-engine, based on Carnot"s well-known
cycle, for the drop passes through a regular and
recurrent set of operations. .A beaker of hot water
and some aniline nia\- thus be made to teach man}-
useful lessons, and furnish a further example
of how the [)rofoimdest scientific truths ma}"
frequentl}- be deduced from the simplest experiments.

THE GREAT NEBUL.\ IX oRloX.

The photograph of the Great Nebula in Orion
(reproduced on the opposite page) is made from a
negative which we owe to the courtes\- of Sir
William Christie, F.R.S., the recent .Astronomer
Royal, and is one of the triumphs of celestial
photography at the Ro\-al Observatory, Greenwich.
No finer photograph of the nebula is in existence.
The reproduction is enlarged three diameters, from a

negative taken bv Mr. Melotte. on December 1st,
KS99. with the thirt\-mch reflector, the focal
length eleven feet hve inches, and the exposure
two and a quarter hours. The nebula seen through
a telescope glows like a vast filmy cloud of
emerald light. Its brightest portions have edges
sharp as in an engraving, and are side by side
with regions of the most intense blackness.

The Great Nebula in Orion, from a negaiuc taken December Ut, li'J<^), with 30-inch Reflector.
Focal length 11-ft, 5-in. Exposure 2\ hours.

HOW AND WHY DO LEAX'ES FALL?

B^

S. BOULGER. F.L.S.. F.G.S.

There is no element which contributes more to the
difference of the landscape as we travel from the
Equator northward than the prevalent character of
the foliage of the trees. In the tropical jungle the
bulk of the trees are dark green, thick-leaved e\er-
greens, a characteristic which extends northward in
the more insular moist climates of coast and island
regions, notably exemplified b\- the flora of japan.
In the Cooler Temperate

Zone the predominant trees V; y. '-, '

are dicotyledonous angio- \ ■\\VV' : \

sperms, the "broad-leaved \ l,',il ■ '.iv.- '

trees" of our foresters, with 4\-'. i '^' 'V

smaller, thinner leaves than I;''"*' '■ ' { V

those of the jungle, lighter .JL i.i, ^1 i

in tint, producing a less ^V.i' V'- •

dense shade, and. for the
most part, falling in autumn.
Northward of these again
the polar limit of arborescent
vegetation is reached by the
striking Sub-Arctic Zone of
" needle-lea\'ed "' conifers,
mostK" evergreen.

It must be noted, in
passing, that this term "ever-
green." though often true
enough of a tree, does not
apply to the individual leaf.
A tree is evergreen when it
retains the leaves of one year
at least until after those of
the next season are unfolded.
\\'e have numerous grada-
tions, from our ordinary
" deciduous " species, which
are bare of leaves for five or
six months in the \ear,
through such cases as that
of the privet, which retains

its leaves through a mild winter, and that of the
holm oak which is only stript by exceptional frost,
to such evergreens as the holly, or the cedars
and pines, that retain their needles for several
successive _\-ears.

If we look at the question of leaf-fall no longer
geographicallv, but from the point of \iew of the
s^-stematic botanist, we find that the lower and
simpler tvpes of leaves do not fall. The primitive
leaves of mosses have no articulation at their base :
the elaborately-divided fronds of most tree-ferns
wither and hang their dead stalks downwards
from the stem : the needles of conifers wither
similarlv, generally after being several years on
the tree ; and the simple sheathing leaves of most
Monocotyledons have not so perfect a system of

articulation as we find in tile Dicotyledons, especially
those with compound lea\'es.

A thouglitless, unobservant conclusion would be
that the leaf dies and then, and consequently, falls off ;

case. Preparations

but this is far from being the

may
it is
and

begin
formed
its cells

•->■•

1 I If • 3

l-roiii a f>hoto!'! ■'_

1- IIjL K

Longitudinal section of a

leaf stalk of horse chestnut

cork layer that

fall of the leaf almost as soon as
in man\' cases the leaf is moist
inflated when it falls. As far
back as 1758, Duhamel
ascribed the fall of the
leaf to a layer of tissue
between the stem and the
leaf, which remained " her-
baceous." i.e., capable of
growth, but could not stand
winter cold: whilst \"rolik,
in 1797, spoke of the ab-
sorption of a layer between
the dead and living parts
hut belonging itself to the
li\ing. In 1848 a Dr.
Iiiman, in a paper com-
municated to the Literary
and Philosophical Society
of Liverpool, described an
inward extension of the cork
of the bark and disruption
taking place through cellular
tissue external to this corky
la\er, from without inwards
■' The provision for the
separation," he writes, "' being
once complete, it requires little
to effect it ; a desiccation of one
- ^ side of the leaf-stalk, by causing

^ -'I \ an effort of torsion, will readily

break through the small re-
mains of the fibro - vascular
bundles ; or the increased size
of the coming leaf • bud will
snap them ; or, if these causes
are not in operation, a gust of
wind, a heavy shower, or even the simple weight of the
lamina, will be enough to disrupt the small connections
and send the suicidal member to its grave. Such is the
history of the fall of the leaf. We have found that it
is not an accidental occurrence, arising simply from the
\icissitudes of temperature and the like, but a regular and
vital process, which commences with the first formation of
the organ, and is completed only when that is no longer
useful ; and we cannot help admiring the wonderful
provision that heals the wound even before it is absolutely
made, and affords a co\'ering from atmospheric changes
before the part can be subjected to them."
In 1859 Hugo von Mohl, the illustrious founder
of the cell theory, chanced to spend his autumn
\-acation at home, so that he observed the successive
fall of the leaflets and the leaf-stalk in the legu-
minous Gyiiiiiodaciiis canadensis with the con-
veniences of his laboratorv at hand. He found that

Vi',

m

J.

/y F. A'aati Clark.
1. 1.

stem and the base of a
shewing the light coloured
causes leaf-fall.

January, 1911.

KNOWLEDGE.

a layer of cork alread\' extended through the cellular
tissue at the base of the petiole in September.
Immediately above this a layer of cells had become
lirown (suberised) : and, separated from this b\- two
or more rows of the ordinary colourless poKliedral
cells of the leaf-stalk, what he termed the separatint,',
or "absciss," la\'er orit,'inated. This onI\- formed
between the 4th and the 15th of October, extending
across the stalk from the inner or a.xillary surface,
and contained in its cells protoplasm and starch-
grains. It is, in fact, what we now term " secondar\-
meristem." \'on Mohl only recognised two layers of
cells in the absciss-laver, which he believed to split
apart, while he thought that tlie tihro-vascular bundles
were broken mechanicall}' b}' the weight of the blade
and the strain of wind and rain. He perceived, how-
ever, that the fall of the leaflets between the lOth and
20th of October, and the subsequent fall of the
petioles was independent of the cork-la_\er fornicd at
least a month before. This cork layer, in fact, is
not formed in advance in those ferns which are
deciduous, in beech, elm or most oaks, \'on Mohl
also noticed that when lea\'es fell suddenly, after an
autumn frost, a thin la\-er of ice had formed in the
delicate sappy cells of the absciss-laj'er, torn cell-
walls evidencing the violence of the disruption.
In 1863, Julius Sachs traced the gradual removal

of the contents of the leaf-cells. The protoplasm
and nuclei are dissolved, the chlorophyll-granules
become disintegrated, the starch disappears, leaving

r .'^sT

h.URE 2.

A beech wliieh has lust the leaves fnjin the ends of
the shoots.

iMCUKIi J.

The teniiiiial leaves still reiiiaiiiin.i; mi hiuleii tree.

only the few \'ellow granules, or the reddened cell-
sap, w hich produce our autumn tints ; while starch,
potash and phosphoric acid travel down the leaf-
stalks to be stored up in the twigs, and only the
waste or end-products of metabolism, calcium-oxalate
cr\'stals, resins and alkaloids remain to be thrown off
with the falling leaves.

In 1882, M.M. Guignard and Van Tieghem re-
turned to the studv of Gyiiinoclacfiis; but began their
investigation in the middle of June, They found
that no cork is formed at the base of the leaflets. It
is not worth while to heal the wound on the leaf-
stalk which is itself to fall in a day or so. The
suberised la^-er was formed at the base of the
main petiole b\' the middle of June : then a
la\'er of meristem, the " phellogen " or cork-
cambium, originates below it and the absciss-
laver above it, before the end of June, This layer
spreads inwards from the epidermis through the
cellular tissue of the bast and wood-bundles. It
consists not of two, but of three, layers of cells of
which the middle row is absorbed. The two remain-
ing rows, still living and turgid, swell outwards w ith
roun<led surfaces, and so create a strain which snaps
the fibres and vessels. These observers also induced
leaf-fall artificially at midsummer, by placing a cut-
branch in a box filled with moist air, and the_\- found
that after the fall of the leaf the cellular tissue of
the vascular bundles whose ends are exposed on the
leaf-scar becomes " merismatic," i.e., undergoes cell-
division, forms cork, and penetrates and fills up the
ends of the vessels.

It is well to bear in mind that prolonged drought

KNOWLEDGE.

January. 1911.

will induce leaf-fall much as does a frost, and that a
laver of cork is formed below the prickles on old
stems of rose or bramble, and below twigs in some
plants which shed these branches as others shed their
leaves. On the other hand, if a branch be broken
through earh" in summer, its leaves wither but do not
fall, no absciss-laver being formed. Coppiced oaks
or the clipped beeches and hornbeams in the hedges
of nurserv-gardens also retain their leaves, as if the
energy- and material used up in the formation of
callus to heal the wounds caused by pruning-knife or
shears left none for the formation of the usual absciss-
la_\-ers. The pollard hornbeams of Epping Forest.
which used to retain their withered foliage through
the winter, have, since the Forest was taken over by
the Corporation of London, and lopping has been
stopped, been gradually regaining the deciduous
character of "spear" trees.

Ever\-one must have noticed the successive fall of
the leaflets and the leaf-stalks in the ash or horse-

chestnut, tlie thick-ended petioles being aptl\- known
b^" children as " bones." since they are b\- no means
unlike the leg-bones of birds. There is, however,
another interesting little point in connection with
leaf-fall which is, perhaps, less familiar, and which is
well illustrated in the photographs, by Mr, Johnson,
of Tunbridge \\'ells, from which our blocks have
been prepared. This is the order in which the
leaves fall from the twig. In the beech this is
hasipefal, i.e., the \ounger leaves at the apex of the
twigs fall first. In the linden, the poplar, and
apparenth" in the majoritN' of trees the fall takes
place acropefally. i.e.. the older leaves at the base of
the twigs fall first.

It is well to notice that here again we have
order and not chance : that Nature has, as we
often find, two or more ways of bringing about
the same result ; and that even in such an
apparentlv simple matter as the fall of the leaf
there is room for a good deal more research.

SOL.AR niSTl'RBANCES DURING NOVEMBER. 1910.
Bv FR.\NK C. DENNETT.

DuRIXG November there ha.'; been a considerable falling ntl
in solar energy, a complete absence of dark spots being
recorded on sixteen days, and on five of these faculic
disturbances were also absent. It is a little peculiar that
the majority of the disturbances have occurred in the northern
zone, which for so long has been comparatively quiet. The
longitude of the Central Meridian at noon on Noxember the
1st was 18° 21'.

As No. Si continued on the disc until November the ird it
is shown on the accompanying chart.

No. 83. — .-X pore in the northern spot-zone, only seen on
the 3rd.

No. 84. — Two pores only visible on the 7th, in the area
formerly covered by No. 75.

No. 85. — A solitary pore also ephemeral, onlv being seen on
the 14th.

No. 86. — First seen on the 16th, when it showed some of the
characteristics of an elliptical outbreak. The leader, or
western spot was 10,000 miles from north to south, and the
group about 3° in length. The spectroscope showed the
C line of hydrogen displaced both on the red and violet sides,
and prominences were visible in projection over the group.

whilst the D:; line of helium was dark through the outbreak.
On the 17th it was seen as a nearly straight group of small
spots 40.000 miles in length. By the ISth it had assumed a
lozenge shaped arrangement of pores, with the largest behind,
or eastward, and when last seen on the 19th there were only
two pores, 26,000 miles apart.

No. 86(7. — A single, not very bkick. pore a little west and
south of the group, only recorded on the 15th.

No. 866. — A minute pair of pores 19.000 miles apart, in the
former area of No. 78, only seen on the ISth.

No. 87. — Three pores nearly in line, also seen on the 18th
only, in the area of No. 79c.

No. 88. — A single spotlet seen from the 20th until the 22nd
in a disturbed area, having apparently come round the limb.

On November the 12th a cur\-ed faculic ridge of horseshoe
form was seen in northern latitude in the position dotted upon
the chart.

The chart is constructed from the combined observations of
Messrs. J. McHarg, A. A. Buss, E. E. Peacock, and F. C.
Dennett, w^orking in places so far apart as Lisburn. Chorlton-
cum-Hardy, Bath, and Hackney, thus making the record
almost complete.

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EXPERIMENTAL MECHANICS.

Bv ^^•. D. EGGAR. M.A.

Mechanics is the mother of t\\o sciences, Engineer-
ing and Gravitational Astronom\'. This statement is

perlia[)s open to question,
astronomers ma\' w isli to

15oth engineers and
claim a more remote

ancestry for their studies. r>ut, \\ ithout insisting on
the precise relationship of the difterent groups, we
may point out that Gravitational Astronomy is very
much younger than mechanics,
and it might almost be said that
she made lier entry into the world
after the manner nf Miner\'a,
apj>earing full grown and fulh'
equipped from the brain of the
g(_)d-like Newton The perfec-
tion of her equipment, and the
unexceptionable propriet\' of her
demeanour commended her to all
mathematicians, with the result
that Mechanics, her real mother,
was received into .their select
circle, taking the name of Applied
Mathematics, and not encouraged
to see much of her other daughter,
tond, it was feared, of low and
irregular company.

Times have changed. Even
the House of Lords must become
more democratic, and engineer-
ing has become so \er\' much of
a great lad_\- as to compel
the respectful attitude of mathe-
matics, and to make her connec-
tion with tr.ide rather a recom-
mendation than otherwise. In
other words, tlu' world must ha\e
engineers, and engineers must
have mathematics, and, therefore,
mathematics has become more
practical. Moreover, in the
engineering profession itself the
problems which rec]uire solution
become more and mt^re of a kinetic
nature. The strains and stresses
in girders and embankments are as important as ever;

Figure 1.
Apparatus for me.as-
uring time with a

tuning fork.

teaching of mechanics, which used to be limited to a
few experiments with spring balan :es and pulleys, has
now spread into the region of kine"'.--;. The concepts
of force and work are undoubtedh- " :st approached
by practical measurements of the efficiency of
simple or complex machines; and it has been
found that \'elocit\'. acceleration, kinetic cner^'\-.

Figure 2.
Measuring tlie velocity of the rim uf a wheel.

moment of momentum, aiul other concepts involving
mo\'ement can best be realized m a jiractical manner.

Figure 3.

but, in addition, the mechanics of movement is grow-
ing in importance, ^^'e move faster nowadays, not
only on the railways, but on the roads, in the water,
and even in the air. Hence it is that the practical

Fletclier's trolley for measuring acceleration.

The measurement of time has alwa}s been a
difficult}- in the way of those who have tried to teach
kinetics by experiment. Electric chronographs
are expensive, and, even where expense is no bar,

KNOWLEDGE.

January, 1911.

they are frequently found wanting either in their of this kind, let us consider the curve shown in

working or in their power of elucidating the problems Figure 4. Placing a centimetre scale along its

in which they are emplo^•ed. A recent adaptation wa\'e crests, we can read off the distances of these

of the old tuning-fork method of measuring time has crests from the starting point of the curve to the

Figure 4. Waw Curve showing acceleration.

revolutionized schools of dynamics. The tuning-
fork method will he best understood from a glance
at Figure 1, which shows an arrangement for allow-
ing a plate of glass to fall so as alwa\-s to be in
contact with a st\le attached to one prong of a
tuning-fork vibrating with known fre(]uenc^'. A
wavv-curve is traced on the glass by the vibrating
point, and the space fallen in a gi\'en time
can be determined by measuring the length of that
portion of the wavy curve which contains a number
of waves corresponding to the given time. Another

Figure 5. Two trolleys for verifying the laws of momentum and impact.

apparatus for measuring the \'elocitv of the rim of
a flywheel bv means of a tuning-fork is shown in
Figure 2. Now a tuning-fork is not ver\' eas\' to
manipulate, and it goes rather too fast for beginners.
Here it is that a great simplification has been
made b\- Mr. W. C. Fletcher, of the Board of
Education.* A strip of steel clamped at one end
carries a paint brush at the other end. A long trolle\'
carrying a strip of paper moves underneath this
paint brush in the direction of the steel rod's length.
Suppose the steel to vibrate ten times a second, then
the paint brush will trace a waw line on the paper,
and ten waves will re-
present the distance
travelled in one second.
The lengthsof the waves
give the velocities, and
the changes in the wave
lengths give the acceler-
ations. Figure 3 gives
an example of the way
in which Fletcher's
trolley may beeiTi-
ploved for measuring
the acceleration when
the trolley is allowed to
run down an incline.
One of the curve trac-
ings made by the paint brush is shown resting
by the side of the plane. As for the wav in
whicli tlic^ accelenition i:, determined from a curst'

nearest half millimetre, thus 0"1. 0"35. 0"S. r45.
2-25. 3-2, 4-35, 5-65, Z"!, 87, 10-5, 12-4. 14-5, Ibvo.
From this, bv subtraction, we obtain the successive
wave-lengths,' viz.: (YId. (V45, 0-65, O'S, 0-95, MS,
l-j. 1-45" 1-6, 1-8, 1-9. 2-1, 2-25. It is obvious from
this that the wave length has been increasing fairly
uniformlv. the successive increments in wave-length
being again obtained bs- subtraction. Thus thev are
0-2, '0-2. 0-15. 0-15. 0-2. ()-15. 0-15. 0-15. 0-2," O'l,
0-2, 0-15. The average of all these is 0-167.
Now, since the wave-lengths correspond to periods

of one-fifth second, it is
plain that the average
increase in the space
travelled in each one-
fifth second is increas-
ing at the rate of 0T67
centimetre in every one-
fifth second. Hence in
each second the in-
crease in the velocity is
5X0'167 centimetre
per one-fifth second, or 5x5xO"167 centimetres per
second. The acceleration is therefore 4' 17 centi-
metres per second per second.

As an example of the way in which the ajiparatus
ma\' be employed we ma\' take the verification of
the law " .Acceleration is proportional to the
accelerating force." The \-ariable force is obtained
b\" var\-ing the slope of the plane. To avoid
ha\"ing to consider the force of friction, the
trolle\" is first connected b}' a string passing over a
pulle\', shown in the figure, to a scale pan of known
mass, and weights are added just enough to prevent

FiGLKI. I

.\n inertia bar ■ set ,.;n motion by a trolley.

thejrolley from accelerating when it is given a start
down the plane. When the waves made by the
paint brush are of equal length the total force down

'■'See School World, .May, 1904.

January, 1011.

KNOWLEDGE.

the plane is exacth' halancfd b\- the scale pan and
weights. Now if the string is reinowd the trolley
will accelerate under a force which is equal and
opposite to that which has been removed, viz., the
weight of the scale pan and its contents. The
acceleration can be measured as before. If the

bullet embeds itself. After the shot the trolleys
retire with equal momenta.

Figure 6 shows an inertia bar, which is set in rotation
In" the impact of a trolley. Vibrating springs are
employed as before to measure the momentum
of the trolle\', and the angular momentum of the bar.

Hmm.

Figure 7.

A vibrator used for measiirin.i,' the anguldr
velocity of a fly wheel.

Figure S.

The vibrator adapted to an Atwood's machine in which a paper ribbon

replaces the string.

observations are now repeated with a different angle
of slope the two accelerations will be found to be in
the same ratio as the two accelerating forces.* An
approximate verification of Newton's Second Law-
may seem unsatisfactory ; but the method has the
merit of making the notion of acceleration nuich
more eas}' for the ordinar\' mind to grasp.

Figure 5 shows how. by means of two of these
trolleys, laws of momentum and impact may be
verified. In one form of the apparatus, employed by
Mr. Ashford at Dartmouth Naval College, one trolle\-
carries a pistol and the other a target in which the

Figure 7 shows the vibrator employed in measuring
the angular velocity of a fly wheel. The notion of
kinetic energ\- becomes clearer after a series of
measurements taken with an apparatus of this kind.

Mr. G. Cussons, of Manchester, to whom we are
indebted for the photographs used in illustrating
this article, has adapted the vibrator to a form of
Atwood's machine in which a paper ribbon replaces
the usual string. The apparatus is shown in
Figure 8. Excellent results are obtained from this
instrument, and Figure 4 is a reproduction of one of
the curves obtained from it.

■■ See Egg.ar's Mechanics, E. Arnold.

CARRIERS OF PLAGUE.

By E. S. GREW.

Wifli i!lii<itmti(iiis fniiii pliutdoritphs hy tlic coiirfcsy i)/ Dr. C. ,/. Miiiiiii. F.R.S.

Technically any animal is a carriL-r df plague
which has plague, and in the organs or blood of
which the plague bacillus resides. In that sense the
natives of India are plague carriers : the rats and
bandicoots of India are still more emphaticalh" plague
carriers. But. in the last resort, seeing that the
instances in \\hich a rat suffering from plague could
inoculate man with i)lague bacilli must lie so rare as

Comiiiission have discovcrcii no fact icliidi icoiihf
support the siii^ot'stioii that pla^iiiic may effect an
entrance into the human or/Jaiiism tliroiis^h t/ie
stomach or intestinal canal. The })robabilities
ot infection through swallowing an\- number of
plague bacilli are cxtremeh' small: and it is
justifiable to conclude that in nature, infection of
rats by feeding rarely or nc\-er takes place, anil that

Figure 1.
An old Bengalpuni Street.

All tlu> iKvellin.!; houses .-iit^ abo\e stables, and therefoie, nil the f;u:e nf it, likely In
he infested with rats.

not to be worth considering, the true carriers of
plague are the animals which con\-ey the bacilli from
rat to rat, or from rat to man, or, in rare instances,
from man to rat. These animals are the fleas which
infest rats.

This conclusion, a j)parentl\' so simple, was. however,
not reached without long continued investigations,
undertaken, at the instance of the Indian Government,
by a commission of bacteriologists (uiidei- thr thrci tinn
of Dr. C. J. Martin. F.R.S. .and Col. I)a\id liruc,'.
F.R.S.), which has been at wdrk since 1'*(I4. Aincnig
tile in\-estigations made by the Plagui.' C'ommissitm's
bacteriologists have been a number which dispose of
the idea that plague can ordinarily be spread h\
jilague bacilli which may be left on the earth — on
the floor of infected houses, or on the soil. Nor can
jilague be transmitted usually by aerial infection.
That is to say, it cannot be transported through the
air, or with wind-swept dust. Nor, again, though this
belief has had a long currency, can it usualh- lie
transmitted through food. flic Indian J^lai^iie

Figure 2.
The interior of a Cooly's Room.

Pnts and boxes roritaiiiing .nrticles of daily diet are lyin^ all i
aftordins; shelter and facility to rats.

the place and

rats do not become infected /)v ciilini; the carcases
of their comrades. The repetition of these facts
has a certain interest at a time when the appearance
of plague among rats in Suffolk has created a ver\'
distinct prejudice against the use of game, of hares, and
e\-en of imported rabbits as food. Everyone would,
of course, prefer not tn eat an^' animal which could
))ossibl\- have died from plague, but no one would
be in the least likeK' to contract plague bv doing so.

In \iew, however, of the fact which is now declared
Iw the highest authorit\' to be well established, that
there have occurred two cases of plague pneumonia
in Suffolk, and that there have been a number of
cases of plague ainf)ng rats in that neighbourhood, it
becomes important to inquire what the probabilities
are of any considerable spread of the infection in
England.

In an\- outbreak of idague in a new locality the
factors which determine the extent and severity of
the epidemic are much more numerous than are
generally supposed, and the margin between danger

10

January, 1911.

KNOWLEDGE.

11

and safety is dependent on factors which are in
themselves apparenth" sh'ght. For e.xample, it has
alread\- been said that plague is spread entirely by
plague fleas. This mav naturally lead to the inquir\-

supposition be in conflict with the recorded facts
that whole families were stricken with the plague,
apparently taking it from one another ? That is
certainly true ; and the answer to these questions is

The house (at Parel) with the plant pot in front, produced a
\ery large number of rats.

whether the last Great Plague of London, which
proved so devastating, was spread by fleas ? If it

Figure 4.

An examination of plague infected rats at one of the Indian
Government Laboratories,

to be sought in the fact that plague has more than
one development. It may develop into plague

Takint

Figure 5.
a systematic flea count.

were so would not this argue that the habits and
dwellings of London in the late seventeenth century
\\ ere much more dirtv than we have any evidence to
show tliat they were ? Moreover, would not the

Figure b.
Piclcing off fleas from live rats for experiments.

pneumonia, which, of all forms of plague, is the most
dangerous and the most infectious. The mortality
in plague pneumonia approaches one hundred per
cent.; hardly anyone recovers from it. Moreover,

12

KNOWLEDGE.

January, 1911.

while suffering from it the patients are dehrious, they
are with difticuit\- restrained from \\alking ahout,

and they cough and spit
incessantly. Their sputum
is full of plague germs,
and is highly infectious to
anyone on whom it ma\-
be discharged. Rats, also,
may have plague pneu-
monia : and there is one
instance at an\- rate in
which a bacteriologist is
believed to have contracted
plague from the sputum
of a plague infected rat.

Pulex fclis 3 . the cat flea.

The Great Plague of Lon-

* t

V

don took place in winter, and a large numlier of
victims no doubt had plague pneumonia ; hence the
virulence and rapidity of the contagion.

What then is the genesis and progress of an
outbreak of plague ? Plague, in the
first instance, appears to arise in -^

certain foci in Asia and Africa,
where it always exists. In a
locality such as Bombav, an out-
break among human beings is pre-
ceded b\' an outbreak among rats.
and if a curve be drawn showing
the rise, culmination and decline of
the plague among rats, it is found
that a rise, culmination and fall of
plague among human beings takes
place in a cur\e almost parallel
to that of the plague among rats,
but occurring about a fortnight later.
The reason is quite plain. In the
native dwellings of India generalh*.
and in the nati\'e villages of the
Punjab, man and the rat live together
like friends. There are two kinds of rats in India, as
there are two kinds of rats in England, though the
numerical proportions of the two kinds are usually
reversed. In England the commonest rat is the so-
called grey rat, .l/^^^ dcctnuiinns. or Hano\-erian rat,

which usually inhabits
sewers, and is a fierce,
strong animal, shy of
h u m an beings. I n
India the commonest
rat is the black rat.
Mils idttiis, which is not
at all shy, and which,
being allowed to do so,
' lives on terms of inti-
macy with the Indian
natix'c. lUit the black
rat is found in England,
in the Thames and
Mersey warehouses; and
the grey rat is found in
Indian ports. The reason why the black rat spreads
plague in India is that it dwells unmolested in the

Figure 9.

Micro-photograph of a 3 PiiKx clicnpia.
the Indian rat flea.

mouse

Figure 10.

Ctcnopsylla miiscnli 3 ,
the mouse flea.

native \'illages. and in the ramshackle nati\-e quarters

of towns : and that, consequently, if it has

any epizootic disease which

can be transmitted to man.

there is an initial probabilitx

of its transmission. In short

the Indian rat is a reservoir of

plague, which is constanth'

being tapped b\- the fleas

which live on it, and which

carry it on to the human being

in the rat's neighbourhood.

On a rat infected with plague 'f^

thirty fleas are by no means Figi're .s.

an excessive number. In one Sarcopsylla iial/nmcca

,■1 ■ T) 1 T J- I? , the chicken flea.

nati\-e house mParel.aii Indian

village, no fewer than three hundred rats were

trapped. Multiply the nunil)er of fleas h\- the

number of rats, and the numlier of possible plague

inoculators thus arrived at will give an indication
of the risk which Indian natives
run of contracting plague when
there is an outbreak ol it among
rats.

It will be seen, therefore, that
even if there were an outbreak of
plague among the rats of Suffolk,
the chances of the development of
a corresponding outbreak are not
\'ery large. But they are further
narrowed In" the kind of fleas
which live on rats in this country
and in these latitudes. There are
six kinds of fleas which have been
found on rats. The human flea
( Piilcx inifans) is found on it
sometimes, but not very often. The
dog flea I Pulex caiiisj is found
more often but still seldom. The
flea {Ctcnopsylla luiisciili) (see Eigure 10)

is also found.

There are. however, three kinds of fleas \\hich are

found commonly on rats, and the consideration of

which is more particularh' rele\'ant to the question

of the contagiousness of

plague. The first is a rat

flea. Typlittpsylld iiuisciiH

(not unlike the mouse

flea), which is common

on rats in some parts of

Europe; Init which will

not bite luan. The second

is the most common Euro-
pean rat flea, CeratopsyUiis

fasciafiis (see Figure 11).

Hut this flea will not

feed on man. except

when starving. The last,

and most important, flea

is Piilcx cheopis (see

Eigure 9), the Indian rat flea, which, unlike the

liuropean rat flea, readily feeds on a number of

\

X...

Figure 11.

Ccratopsylliis fasciatiis 3 ,
the European rat flea.

Jan'uary, 1911.

KNOWLEDGE.

13

ibsence of rats it

.ill

dil

animals. In the
bite man.

It will be seen at once how important this factor
is. The var\-ing appetite of the different kinds of
fleas modifies to a great extent the probabilit\- of
the transmission of plagne to man. If it were
possible, or probable, that the European rat flea

should alter its habits and adopt man as a host,
the probabilit\' of human plague in Europe would
be of an entireh" different order. At present
northern Europe, and, to a less extent, Europe in
the temperate zone, seems immune from an out-
break of plague on account of the habits both
of the grey rat and of the flea which lives on it.

CORRESPONDENCE.

PODL'R.4 SC.-'iLES.

To the Editors of " Kxowledgi;."

Sirs, — While fully appreciating Mr. I'lasUitt's kind rufer-
ence to my article, for which I thank him, there are yet
certain points in liis letter to yourselves witli which I, for one,
cannot agree. I cannot admit, for instance, tliat in the
Podura scale mounted dry we are " left with the only alter-
native (that is, in being mounted in a medium) between the
normal of air and the scale itself"; or, that for that reason,
" we make no advance upon the earliest methods." .'\s I
understand it, with a scale mounted dry. and tight against the
cover glass, there is no normal of air, but perfect optical
contact with glass throughout, also with the cedar oil of the
same refractive index between that and the objective. Mr.
I'laskitt speaks of the scale, not being flat, giving rise to
distortion. That has not been my experience, though it may
be said of other kinds of scales, such as those belonging to the
Moth and Butterfly.

Assuming that the widest apertured oil immersion objective
is employed upon this scale, the best way to discover whether
it is working at its maximum is to look down the tube of the
microscope after removing the eye-piece. If the back lens is
seen then to be filled as to tliree-quarters of its diameter with
white light, this condition may be said to be fulfilled. Under
no circumstances could this be obtained with an objective of
r40 N.A. were there a stratum of air between the object and
the cover glass.

These conditions were fulfilled in all my work upon this
scale. For myself I never required other proof of optical
contact, than the flashing out of the object in brilliant light, as
if the scale were self-luminous. Apart from this, however,
my friend, Mr. E. M. Nelson, with whom, at that time, I spent
many delightful days at his house over the microscope, tested
it for his own satisfaction with the Vertical lUuniinator, when
the test was always justified.

As to the three-quarter cone of white light at the back lens
of a wide apertured objective; this for a long time now has been
looked upon as the ideal illumination, where the greatest resolv-
ing power is combined with perfect definition. Mr. Nelson, in
his Presidential Address to the Quekett Club in the early part of
1895, went fully into this cjuestion. The address will be found
in Vol. 6 of the Journal of that Club, beginning at page 14, but
as some readers may not have access to it, I beg to be
allowed to make the following extract for their benefit : —

" It is common knowledge that when a full cone is employed,
the resolving power falls off, and it has been customary to
account for this falling oft" in the resolving power by the
outstanding spherical aberration in the objective. To test the
accuracy of this current notion a critical image was set up,
and matters arranged so that access could be obtained to
the back lens of the objective without disturbing any of
the adjustments. When a full cone of light was used (that
is, the back lens entirely filled with light — T.F.S.) the
resolving power fell oft, and when a three-quarter cone

was employed it was as usual restored again ; a stop
was then placed at the back lens, cutting off the
peripheral unilluminated annulus. We had, therefore, an
objective of less aperture, but illuminated by a full cone.
Under these circumstances one would have expected to see a
critical image, but not so, and this is the crucial point. In
order to obtain the maximum resolving power for that reduced
aperture the illuminating cone had to be reduced until three-
quarters of the back lens was illuminated,"

It follows, then, that given the three-quarter-cone as the most
ideal illuminant, such a cone of an oil immersion objective of
r40 N.A. must have a much greater resolving power than the
similar cone of a dry objective w^hose maximum aperture is
only rO. Up to a certain period dry glasses were the only
ones available. All my photographs of the scale were taken
under the first conditions ; hence, unless I blundered greatly,
they must have made an " advance upon the very earliest
methods."

We now come to the question of oblique light as helping
towards the further elucidation of structure in the Podura
scale. Mr. Plaskitt says, that when central light is used,
"there is insufficient contrast to bring out several of the finer
phases of detail. It is much the same as if one placed a
piece of plain glass in the midst of a lamp flame and were
asked to observe its uneven surface, or to direct a telescope
boldly towards the full moon and be expected to trace its finest
details."

The illustrations on the face of them are apt enough, yet, I
tear for all that, a little misleading. The conditions of pro-
ducing an image in the microscope differ from those concerned
with unaided vision upon natural objects. In the microscope
it is of a two-fold character ; one geometrically, as in ordinary
vision, taking up the centre of the back lens of the objective ;
the other, by diffraction, occupying the outer unilluminated
ring. Both images reach the eye as one, that produced by
diftraction strengthening the image produced in. the ordinary
way of vision. Neither with regard to the telescope and the
moon do I think the cases are exactly upon all fours with
each other. In one, the microscope, the light is tilted to the
object ; in the other the telescope remains the same — the moon
it is that revolves. Mr. Plaskitt's photographs do not exhibit
shadows such as when details in the moon are seen in profile,
proving, to my mind, that the conditions of production are not
the same.

Like Mr. Plaskitt I have been unable to discover any
dift'erence between the two sides of the scale, though I have
had them mounted between two thin cover glasses, to enable
me to get at each side. It is, indeed, altogether a puzzle, this
secondary structure, and such for the present, I fear, it umst
remain. One thing, howe\'er, I would say in conclusion. If
my own experience with minute structure is any guide, and
with all deference I say this, it is that oblique light will
not guide us further, but will only make confusion worse
confounded.

Yours faithfully.

T. F". SMITH.

ON THE OCCURRENCE OF SOME SMALL FINELY
WORKED FLINTS IN PALEOLITHIC GRAVELS.

ISv LIEUT.-COL. UM)1:K\\"()()1).

At various times during the past two years I ha\e
been carefully searching two gravel pits in which
paleoliths are found — one within a mile of Ipswich,
the other at Upper Dovercourt, near Harwich.

The gravels of these two pits are t)f entirch'
different ages — that at Dovercourt being a terrace
gravel of the River Stour, and situated eight\'-seven
feet immediately above it ; while the gra\el at
Ipswich is not apparently connected with any ri\er
system, and as it rests on London cla\' (the base bed)
and is surmounted with glacial boulder clay and
interlocated with fine sand containing quartz pebbles,

with implements ni<istl\' nnpatinated. or onh' slightly
so. of Mousterian t\pe. consisting of small tools,
from three to fi\'e inclies long, assegais, side kni\es
or clio|>pers. dressed flakes, rubbers, scrapers (round
and hollow ) and dressed bones, and a fish hook made
Irom a halibut's clavicle.

In the bed below the cla\' band are found tlie
l)ones of Mammoth, two kinds of Rhinoceros, Bison
briscus. Bos primii^ciius, and the Horse, while the
implements are of late Acheullien t}'pe. large and
beautifully worked baches, together with small
tetragonal and hexagonal borders, dressed flakes,

rubbers of a peculiar
^ kind, and a series of

ilO

\ ^•r\•

s m a 11 s i d e -

(1

flints of
numy ap-

Froin Gant's I'it. DoNfrcourt

rounded diorites, sarsen stones and other erratics, it
ma\- be assigned to Middle Glacial age. and is
undoubtedlv much older than the Uo\ercourt dejiosit.
In this latter pit no regular Acheullien luic/ics are
found, as at Dovercourt, and no large implements of
war, until we come to the lowest bed of red sand,
with large blocks of flint, and a few other stones,
similar to what Rutot calls the "gravier dii fond."
fmmd li\' him at (ireville, which lies directh on the
base bed, or London
clav, where we get
verv large parallel-

flnc-l\- chipi

flaked, rough-point-
ed "Coh/).s dii poin,i>"
rubbers, and so on,
but no small side-
worked tools.

The Dovercourt
pit. on the other
hand, consists of
a mass of gravels and sands resting on the London
clay to an average depth of twelve feet. These are
divided bv a band of clay about half way down, of a
few inches in thickness, which separates the bones
and implements into two distinct zones. In the
upper beds are found the remains of deer of lorn'
species: — Reindeer, Reil Deer, and P'allow, this
species of a large kind which has also been found at
Clacton. Boar, Wolf and Arctic Fox bones, occur

w ( 1 r k e
almost pifji
pearance, consistmg
of delicate hollow
and round scrapers,
saws, and very small
pointed tools like
arrow or dart heads.
These latter are so
led that it is necessarv to go to
specimens of late Neolithic culture to find
their eipials. and thnut;h this is so. their deep
patination and scratched surfaces point to an
anti(]uit\' iar greater than the Acheullien haches,
which are h'ing in situ, un -water worn, while these
small t\pes. with some large and rude forms. ha\'e
e\identl\" been washed in from an oldiT gra\"el. In
till' gravel at Ipswich c.xactK' similar (liminuti\e

CO

Frniii Hdltoii and LaiiL;hlin's Pit. Ipswich.

implements occur at depths

ranging

from ten to

thirt^• feet from the surf;ice.

but are

considerabh'

more numerous.

The large number ol the

se small

w (11- worked

implements which m\' friend, Mr. Moir, and myself
ha\e collected is very remarkable, and brings into
prominence some questions which have not hitherto
been discussed. Firstly : How is it that in our
Museums, many -of s\hich contain large collections

14

January. 1911.

KNOWLEDGE.

15

of magniticent weapons of War and the Chase from
the principal river gravels, these paleoliths are seldom
shewn ? It is almost a certainty that they occur
evervwhere, but owing to the fact that workmen are
onlv paid and encouraged to look for the larger
specimens, presumabh' the\- are generally overlooked.
Secondlv : These small fabrications are not to he
found in the later gravels, as in the case of Dover-
court, abo\e the clay band, nor are they found
associated with large early Neolithic implements of
Cisburv and Eastbourne. This seems to point to
one of two conclusions, either that side-pressure
flaking or "nicking" became a lost art at one early
period and was not resuscitated till later Neolithic
times: or that the workers (possibly a special race)

of so-called "pigmy" implements and small side
work generally were driven from districts where
their ancestors made these "industrial tools," as
Rutot so aptly describes them, an;' did not again
migrate to the same places for many ":s later.

Thirdh-: I would suggest more h,^ ; would be
thrown on the present mystery of pati/vlion, if a
general system were adopted of classing tiu' various
implements in all the gravels of England according
to their forms and respective ages : and the gaps in
the evolution of man's handiwork and arts would be
more tilled up by such a system than at present.

In the accompan\ing illustrations the finds of the
two pits respectively are shown in types, and with
the name of the pit in which each was found.

THE MYSTERY OF THE FLORAL PIGAH^XTS.
Bv P. O. KEEGAN. LL.D.

Thk literature on the subject of the colours of flowers has
been very voluminous as respects the final cause of the
phenomena, but a truly scientific explanation thereof has
seldom been attempted. We do not want to disco\er the
purpose which these lo\ely pigments fulfil in the economy of
the plant, so much as the chemical and physiological efficient
causes of their appearance. The chemistry of plants requires
to be studied, and the products of the physiological processes
going on in their interior need careful detection and distin-
guishment. In this way only can the laws which go\ern the
vital activity be discovered, and thereby also a true scientific
understanding of the phenomena be attained. The corolla is
the organ wherein the yellow, blue, and red colouring matters
are chiefly produced, and hence its physiology has to be
carefully studied and determined, not only in itself, but also
in its relationship with that of its neigbouring organs, viz., the
stamens and pistils. We know that the corolla grows \ery
rapidly, that it is the seat of energetic oxidation and at times
considerable transpiration : its assimilatory power is generally
feeble, and it has a poor de\elopment of the vascular system,
i.e.. of the conducting apparatus. Hence the appearance of
the pigments in the corolla has been explained in a general
and rather vague way by simple modifications in the phenomena
of cellular nutrition and of cellular chemistry (Curtel" ).
Chlorophyll is not produced or regenerated in the corolla
owing to insufficient nutrition, and hence carotin (the pigment
of the orange and deep yellow flowers) is allowed to appear,
while the blue and red pigments are due to the energetic
oxidation of which this organ is the special seat. This
explanation seems to account fairly well for the production of
the yellow pigment (carotin), but it fails to throw light on the
fact that the red and blue pigments (anthocyan) are e\idently
evolved by a verj' special physiological process, which does
not generally take place in an\' other part of the plant with a
strength and completion at all comparable with that proceeding
in the tissues of the corolla. The mere oxidation of an organ
is not sufficient, unless something is produced there indepen-
dently, whereon the oxidation may operate. If the corolla
possesses a very feeble or annulled assimilatory power, its
protoplasm exhibits a very energetic deassimilatory power,
and this latter fact is proved to demonstration when the
chemical constituents of the floral parts are compared with
those of the other organs of the same plant.

A series of chemical analyses of common plants performed
by myself (see The Xaturalist, 1902-10). revealed the
important fact that, while the flowers of certain species are
habitually tinted purely and \ividly. the quantity of tannic

chrcmogen contained in the other organs (stem, leaf, root) is
or may be, extremely small. Hence, the conclusion was
readily suggested that the formation and development of the
blue and red pigments in these cases were strictly local, and
absolutely confined to the floral envelopes, i.e., they were not
necessarily dependent on the particular amount of tannin
produced by the organism in its entirety. Now, as tannin is
a product of deassimilation of a high grade, it seemed certain
that this particular physiological process was carried on in the
corolla \ery energetically ; it was pushed further there, as it
were, than in the other organs of the plant. The question
then to be decided was in what manner did it act. and what also
were the real causes of its specific energy and completeness.

It became clear that it was not (as M. Curtel opined)
merelv because the corolla possessed feeble powers of
assimilation, that, therefore, its powers of deassimilation should
be raised correspondingly. The law of plant physiokvgy
applicable to this case is that processes of special deassimila-
tion are brought about in certain cells to the profit and benefit
of other neighbouring cells. The albuminoids of the corolla
cells minister to the pressing needs of the stamens and
pistils. The vital activity incident to the process of
fecundation, the formation and diflerentialion of the stamens,
ovules and seeds, etc., induces a powerful drain on the
albuminoids of the corolla, whose molecules consequently
break up ; the nitrogenous nuclei thereof are separated and
pass over as much as is required to the cells of the stamen
and pistil, while the aromatic nuclei remain behind as tannic
chromogen, the precursor of the brilliant blue and red
pigments. Numerous experiments performed by myself (see
Xnfiire, Ixi., 1051 render it certain that the conversion of
tannin into visible pigment varies in intensity and completeness
very considerably, according to the particular petal examined.
In cranesbill. tufted vetch, peony, and sweet pea the conversion
is complete ; in foxglove, carnation, and some roses it is nearly
so; in clover, sea pink, and flowering currant it is not
complete : while poppy, burnet and cineraria are still further
remote from perfect development of tincture. And, inasmuch
as difterent species of plants belonging to the same genus
evolve habitually either blue or red flowers, while the
chromogen of all is exactly the same substance, there can be
no doubt that these diff'erences can only be explained by a
diversity in the development of the pigment. As already
suggested, the most developed in this respect are those plants
which habitually e\olve blue or purplish-blue petals, and it is
these very plants which exhibit the most intense and energetic
reproductive capacity.

Annales dcs Sciences Xatiirclles.— Bot. Ser. 8, t. 6, page 221.

ON THE STUDY OF DOUBLE STARS BY AMATEUR

OBSERVERS. W

Bv G. F. CHAMr.ERS, F.R.A.S.

PRACTICAL HINTS ON OBSERVING DOUBLE STARS.*

Dimensions of telescopes in inches of aperture
must not be regarded as conclusive as to the
possibilities or impossibilities of di\"iding close
Double Stars. There are several factors of import-
ance involved in the matter : ci^.. the (jualitx' of
the object-glass ; the steadiness of the mounting :
the power of the observer's eye : its training to detect
small }>()ints of light : his skill and experience
generallw How important such points as these are
is well illustrated by a remark b\- Burnham, made
many many years ago, when he presented one of his
early catalogues of new Double Stars to the Royal
Astronomical Societ\'.+ Speaking of some measures
which had been placed at his disposal bN' Baron
Dembowski he sa\-s : — " F"e\v obser\-ers ^vould be
able to measure such stars, and those habitualh-
observed by him. with an aperture of onI\- 7 inches.
It is another illustration of the truth that much more
depends upon the observer than the si/e of the
instrument. I ma}- add that nothing has been more
gratifying and flattering t<> me than to find m\'
measures of a difficult pair with INA inches aperture
agreeing closely with the measures of Baron
Dembowski with 7 inches."

Another illustration of the proof of lunidiani's
general statement here is to be found in the Double
Star work done many years ago micrometrically by
Dawes, and in another aspect (the literar\- one) by
Webb. The form of micrometer best adapted for
general use is that known as the Bifilar micrometer
mounted in conjunction with a position circle. For
the benefit of beginners in the use of such an
instrument it is suggested that after bringing a
Double Star into the held of view the milled head
which moves the position circle be turned until the
position wires are approximately parallel to an
imaginar\- line joining the stars. The stars are then
by means of the slow motion on the telescope to be
brought between tlie position wires, and then a final
adjustment of the wires to parallelism with the
aforesaid imaginar\- line is to be made. The
distance wires are then to be approximateh- adjusted
to the distance of the stars, and then by means of
the slow motion of the telescope the stars are to be
brought on these w ires at a place clear of the position
wires, and the final rectification made. It will be
found most convenient to make these measures thus
at places on the wires where thev do not cross the

position wires. Two readings, one of position and
one of distance, are then to be taken and entered on
a printed blank form of which a specimen will be
given presentl\-. It is advisable to take at least
four measures of each sort, and treat the mean of
the four as the result to be placed on record as the
measures of the star observed.

In measuring Double Stars it is important that the
observer should so hold his head that the line joining
his e\'es should either be coincident in position with
the line joining the stars or directh- at right angles
to it. Carrying out this suggestion mav sometimes
involve a strain im the muscles of the neck which
must be guarded against, and this will best be done
by using a diagonal reflecting jirism on the eve-end
of the micrometer. The angle of position required
is that obtained by measuring round the circum-
ference of a circle (with the principal star of the pair
in the centre) from the N. point round to 360°,
backwards contrarv to the motion of the hands of a
clock. The reading of the micrometer w'ires should
be 0 ami .)(j() when the wires are \'ertical. There
is no test of the verticalitv of the wires which can be
quickh' applied, and when the instrument is attached
to the telescope for use the position of the zero will
be found to be slightly different from night to night.
It is not worth while, therefore, to attempt to have the
zero in the correct place. And after tiie micrometer
is attached to the telescope preparatory to starting
work, or during the observations, the angular error of
the zero point out of place is obtained in the following
manner and applied as a correction to the mean
reading of the (losition angle of the star. The wires
are brought apjiroximatelv to point East and West
and a star of an^• sort is brought into the field. The
slow R.A. motion of the Equatorial is then used, and
hv trial the star is caused to tra\'el along one of the
position wires, the observer adjusting the position of
the w ires until the motion is along the wire. This
done the wires then lie along a parallel of declination
and are therefore displaced 90"^ from the N. point.
Subtract 90' from this reading and we have the
zero error. On the position circle there are usually
two verniers ISO'-" apart, so the observer has a choice
of readings 180° apart ; and, moreover, the \\ires will
be in the same position on two stars really differing
in angle h\ 180" so that it may be necessary to add
180 ' to the resulting measure. Whether or not this

III the |)repaiati()ii of this seclion I h;i\e been iii;iteriallv helped li>- Mr (i. M. SeabroUe, F.K.A.S.

! Mcliiiiirfi h'.A.S.. Mil. xli\', page 147.

16

January. 1911.

KNOWLEDGE.

17

must be done must be settled by the estimated
position of the star, or b\' consultini; other previous
measures.

Thus far we have spoken of taking measures of
distance b\- adjusting the wires on the stars: and if
the micrometer screw-head reads zero when the wires
were over each other we should onl\- have to convert
the divisions of the reading on the stars into seconds
of arc, and the angular distance would be had. It is
not without risk of error that we can adjust the
screw so as to read 0° when the wires are coincident,
and the difference in the expansion of the steel screw
and the brass in which it is mounted would soon
cause an error in the value of the zero which might,
however, be allowed for when ascertained. But it is
better to avoid this complication of error by taking
measures of the star w ith the moveable wire first on
one side of the tixed wire and then on the other.
The distance through which the wire is moved will
then be double the interval between the stars, and
dividing this by two will give the actual interval :
which process also has the good effect of halving the
error of observation. Thus, it is advisable that the
reading of the screw-head should only be approxi-
mately zero when the wires coincide. If the
readings are taken when the\" increase with the
increase of the distance of the w ires thev are called
"direct": and when the mo\eable wire is on the
other side and they decrease w ith the increase of the
distance of the wires, thev are called '' indirect.''
Since the numbers decrease from 100 (or from what-
ever may be the reading of the screw-head) on the
indirect side we have to subtract the indirect read-
ing from 100 and add this to the direct reading.

To avoid risk of error and for convenience' sake,
it is well to adopt the fiction of calling the reading
1000 when the wires coincide, that being the usual
number of divisions for 10 revolutions of the micro-
meter screw. It follows, therefore, that all readings
within this distance of the wires a.re positive, and we
have only to subtract the smaller reading from the
larger to get the double distance of the inters-al
measured.

For instance : suppose that a direct reading
embraces one revolution (= 100 divisions) and 15
more, making a total of 115 divisions. Add to this

1000, and write down the result

1115. The

indirect reading of the same stars after crossing the
wires will also be one revolution (100 divisions) and
about 15 divisions over, but as we are reading back-
wards from 100 the reading actually is about 85, sav
80. (For it is not likely that the wires coincided
exactly at 0). On the assumption that coincidence
takes place at 1000, we write down 880 as the
indirect measure : then J-i-^y ''"— " is the distance of
the stars in divisions of the instrument.

To find the value of the divisions in arc, separate
the wires by a known number of revolutions, and
note the time that a star on or near the equator takes
in passing transit-fashion from one wire to the other.

Then, since 15" of arc are covered in 1* of time the
number of divisions (100 time: the number of
revolutions) divided by 15 times t>:; time of passage
in seconds will give the number o' divisions which
correspond to 1" of arc*

Seeing that it often happens that : asures have
to be reduced under circumstances uni vourable to
accurate mathematical thought, it is well :^ resort
when possible to mechanical labour-saving expedients.

One of these available for Double Star w -k is
a ■■ Barlow lens," the usefulness of which seims
now-a-days to be very little understood. It is an
achromatic plano-concave lens which has a powerful
magnifying effect, and by inserting such a lens
between the object-glass and the micrometer a few-
inches inwards from the latter an image is altered
in size so that the distance between the two stars
can be made to accommodate a certain number
of micrometer divisions without fractions. For
instance, the magnification of a pair of stars may
be so adjusted that 10 divisions correspond to 1" of
arc. After finding the value in divisions of a measure
we have onh- to move the decimal point, and then a
value recorded in seconds of arc presents itself.
Should this value not be absolutely correct we learn
at anv rate the percentage of the error and appl\- it
in writing down the definitive distance.

The following forms are recommended for use.
No. 1 shows the method of entering observations
as they are taken, and No. 2 the method of recording
the final results for permanent reference : —

No. 1. TEMPLE OBSE R\'AT() RV.
DOUBLE ST.\KS.

Date: Sept. 6. I'JUyr,/.
S 22IS
K. A. //- J'.l. Dec. +fiJ //.

PDsrrujx.

Wires E. i W. 106' 2
90

Mag.

DISTANCE.
Direct. Indirect.

Zero error

Readings.
SS'j
57-0

srn

5S'5

76-2

1017
1018

101 7' 3
981-3

982
981

981-5

230-8

57-7
76-2

161-5

Pos.

Dis.

( A.B. .}J1-5
I A.C.

I A.B. 1-80
A.C.

A more exact method of obtaining this result is to measure the distance of two stars whose position is \er\- e.\actK known
such as certain stars in Pleiades. As to this see Gledhilt's " Double Stars."

18

No. 2.

h. m. s.

ISSO Approx. R.A.

/; 39 35

Cor. for 1900

17 39 12

KNOWLEDGE.

TEMPLE O B S E K \' A T ( .) K \' .

Nan.

Mas,'".

Struve's number 22!8
h „ 7137

January, 1911.

ISSO Appr.ix. Decl. 63° 7J'

I A. (r5 Cor. for 1900 63' 44'

jB. 7-7

(c.

Position.

No. of
(Jbs.

Di:,l."

No. of
Obs.

Date

180 +

Observer's
Name.

Remarks on Observation.

Notes on previous measures. &c.

34S 2

,•)

2-29

2

S3 -70

s

-

1 S3 2-7 2" 30 336' -7 1

349 H

.'}

2-03

2

■70

s

349-2

4

2-44

2

■72

s

3 I!--)

4

ISO

7

094)7

s

Gledhill has made the folldwinsj; suggestions as to
Double Star observing which he says embody the
recorded experience of Strin'e, Sir J. Herschel,
Dawes, Dcmbuwski, and Secchi : —

(II At the outset it must be remarked that the Observatory
(doors, windows, slit, and ventilators) sliould be throw n
open at least an hour before observation begins, in ordi-r
to reduce the temperature of the room to that ot tiie
e.xternal air.

(2) If the definition be bad and the motion great, it is use-
less to attempt the measurement of Double Stars. In
short, if a power of at least 300 cannot be used, the
results cannot generally be of any value.

(31 Very bright stars should be measured in daxlighl nr

twilight.
(41 The observations should be made near the meridian

if possible.

(5) The observer should be in an easy position — the prism
effectually secures this ; and the driving clock ought to
go smoothly.

(6) The bright-held should be used almost exclusively — red
and blue colours are most in use.

(7) Use the highest powers possible, and always the same
powers.

(8) A moderate number of measures of an object on each of
two nights is better than a large number on one night.

(9) Use printed forms.

(10) Enter date, hour, weather, and distance from meridian,
before observation begins.

(11) Notes on definition, general impression as to the %alue
of each measure or set, etc., cannot well be too copious.

(12) In all doubtful cases make a sketch. ,nid .idil full
description. ■■

.\. few more miscellaneous hints aiiplicablc to
telescopic work on Double Stars will now be given.

Use a dew-cap of a length equal to two or e\-en
three diameters of the object-glass; and it is well t<i
have the dust-cap tit the
saves moving the
begun.

Remove and carefullv

end of the dew-cap as this
itter ever\' time that work is

cap the micrometer everv

night to kc'p dust and spiders from getting on to
the w ires.

See that the Right .\scensi(.)n antl Declination of the
stars which you are going to measure are for an
epoch sufficiently recent that you can make sure of
finding the star \-ou want, or you ma\- find yourself
measuring the vvrong star. The epoch of 1900 is
sufficiently recent, and the principal star of every
pair given in these articles is sufficiently bright that
there should be no difficulty in dropjiing upon an\-
star wanted : but in all cases of doubt the places
ma\- be brought up for Precession for any epoch
later than 1900 h\ means of the Table of Precessions.

Examine by da\light the telescope and accessories
and see that everything is ready for use in its place
and in working order; or. come night and the right
star brought into the field, and you may find some
of the moving parts of the telescope or micrometer
out of order and not be able to rectify matters by
lamplight.

For reading a micrometer small electric lamps with
a pinch contact are the best for use ; but whatever
lamp is employed, take care that the light is to such
an extent shaded as not to endanger the sensitiveness
of the eyes.

Take as many readings as you can remember
before writing down any of them, but be sure you do
remember them. It is a great advantage to have
an assistant to write ddwn the figures whilst the
observer is callmg them out. In this way the
observer is able to keep his eyes unimpaired liy too
much contact with light. Small electric lam[)s of
three candle power w ith sw itches fixed to the verniers
of the setting circles are valuable accessories.

Have a movable slide with red, yellow and blue
glasses fitted in front of the lamp which illuminates
the field, and also a stop+ to control the amount of
the incoming light. In this way the illumination of
the field can be readily adjusted. It is always well
to use sufficient light to ilhnninate the wires even

' Handbook of Double Stars, page 83.
+ A -slide of smoky glass shaded off by gradations of tint answers well for this purpose.

January. 1911.

KXOWLiiDGE.

19

though the stars under observation (or one of them)
are too faint to permit of continuous vision. Bright
wire illumination on a dark field is verv useful in
such cases, but this may be beyond the reach of
many amateurs.

A second pair of distance " wires " of thicker web
will often he found verv useful ^\■hen faint stars have
to be measured, and the illumination of the field has
to be kept down so low as to render the ordinary
webs invisible. For these thicker "wires" the guy
lines supporting a web may be used. The}- are of
about the thickness of a fibre of silk and consist of
many ordinarv lines of web made b\- the spider into
what ma\- be called a cable.

It will occasionallv happen that the " w ires "
(spider webs) of a micrometer break, as the result, it
may be, of lack of care in handling the instrument,
or even o\\ ing to the weather. This may be a source
of inconvenience of a serious character to an observer
if he is living at a place remote from an optician.
A thick metal wire is renewable without much
difficulty by anvbody possessed of a moderate amount
of mechanical skill, but to replace a genuine spider
line may be a matter of some difficult\', first of all to
obtain such a thing, and then to fix it.

In order to obtain a supply of spider line take a
piece of moderately stout iron or copper wire about
9 inches in length and of such thickness (sa\' 22
Birmingham wire-gauge) as to be fairl\- rigid when so
bent into the form of a 2-pronged fork that the
ends may be about three inches apart. Ne.xt, hunt up
a spider and persuade him to attach his web to the
wire fork near one end and then cause him to drop
a few inches and catch the web on the other prong
of the fork : then b\- turning the fork round one can
wind up as man\- turns of the web as one cares to
ha\e, taking care to keep each new turn separate
from, that is, not in contact with, the previous one.
If this part of the business has been satisfactorily
accomplished a stock of spider line will have been
laid up for use.

The next thing is to render the lines secure on the
fork before selecting and removing one preparatory- to

transferring it to the micrometer. This is done bv
t(-)uching both ends of each \;urn of the coil where it
jiasses round the fork with a droj of shellac varnish
or other sticky stuff. When this has set and is dry,
the removal of any one web mL y be accomplished
without affecting the others.

\Mien it is desired to take a web < .vit of stock in
order to use it, make a second stout wire lork, rather
less in breadth between the prongs than the first
one. Put some sticky stuff on the tip of each prong
and lift off a length of line from the storage fork.
Remove the cover of the micrometer : clean off any
old ends of broken web : touch with \arnish each
spot where the ends of the new- web are wanted to
go, and drop the new web into its proper place ; let
the varnish dr\- ; and when the web is found to be in
the right place and secure, cut off any overplus with
a small pair of scissors. This final action in the
work of renewal is more easily described than carried
out, but with a little patience and the spoiling of a few
webs, a final good result mav reasonably be expected.

If \ou cannot secure the cooperation of a living
spider to provide a new web, and have none in stock,
search must be made for an old web in situ, and a
suitable portion picked out and ren-ioved with a
forked wire (such as already described) and baited,
as it were, with some stickv stuff. A web thus
casuallv obtained n-ia\- probably be dusty, and may
perhajis consist of more than one single strand, in
which case certain obvious precautions must be
taken and things done.

It will seldom happen that marks cannot l>e
detected on the sliding fork of the n-iicronieter to
indicate where old webs have been attached, and
therefore, where new ones must be applied so that
they may be parallel to one another. Use a screw-
driver which fits properh- the small screws of the
micrometer when it has to be taken apart. A sharp
bradawl is a good substitute. Nothing looks worse
than the head of a screw- damaged b\- a tool unfit for
work. While the screws are out, put them in a little
box for safe keeping, for small micrometer (and
other) screws have great straying power.

SPECULATIONS.

In the volume of which I have made so much use,
Innes has entered upon some reflections and specula-
tions which, as the_\- are not of the wild and
irresponsible character so common now -a-da\-s. I
gladly quote b\- way of conclusion to this prelhninar\-
dissertation because of their present interest and
prospective usefulness. He says : —

" The study of Double Stars will always be
interesting from the Newtonian point of view, and
in the case of the brighter pairs, the spectroscopic
determination of motion in the line of sight will lead
to a knowledge of the true position in space as well
as of the absolute dimensions of their orbits, and
hence their paralla.xes. The irregularities of their
orbital motions (already ascertained in a few- cases.
which will multiply as observations grow more

precise) indicate the presence of disturbing bodies.
For these reasons even the Binaries w ith the best-
determined orbits deser\-e careful and regular
observation. From the astro-physical point of \-iew,
it is hoped that much max- be learned from their
stud\-. A contracting and rotating mass of gas may
e\-entuallv reach an epoch when it will become
unstable, and separate into two or more portions
forming a Binar\- system. It is evident that this
critical period will depend on the constitution of the
body, its speed of rotation, mass and temperature.
S\-stematic observations, micrometric and spectro-
scopic, should in time enlighten us on these,
at present, obscure subjects. When we are able
to arrange the elements of the orbits of say one
thousand Binary pairs in tabular form, with their

20

KNOWLEDGE.

January, 1911.

spectroscopic history, both of constitution and of " It is true that of these « Crucis is not a Binary,

radial speed, including for each the proper motion It is perhajis all the more remarkable for that reason,

and its solar comjwnent. we shall be in a position to being one of the brightest stars in the skv, and shown

attack questions relating to the constitution of the by photography to be surrounded by a cluster, or rather

1 2703 Dulphini.
Mags. 7i, 7t, 7i : Distances 25", 71", 5'/'.

> Dilphiiii.
MaKs. 4i, 5.; : Distance 11"

ji Cephei.
Mags. 3t, S: Distance 13",

Cephei.

Mags. 5i. 8A, si, 10: Distances li", 12", 20"

sidereal heavens, which are to-da\' be\-ond the realms
of reasonable speculation. In this respect the stars
of the Soutliern hemisphere offer at least as attractive
a held of investigation as those N<irth of the equator.
In spite of neglect, the Southern s\-stems alread\-
exceed in importance those of the North, .\mong
them may be quoted : —

bv rings, of ver\- faint stars, in the centre of wliich

Sirius
(X Centauri
y V'irginis
y Liipi
y Centauri
y Circini
y Sextantis
^ Aquarii

4

T

Eridani

Crucis

Muscae

Aquarii

Scorjiii

Liipi

Phoenicis

Sagittarii

the two large stars are. as far as can be ascertained,
absolutely stationar\-. Are these gloriously brilliant
stars devoid of mass, or, it the\- shine with an
intrinsic brillianc\- of surface e(|ual to that of Sirius.

at what distance must the}- l>e apari. Limi. g,

t that gravitational
motion becomes too small tn be detected even
in a centur\- ? Speculation and analogy alike fail
us. and a systematic study of all Double Stars is alone
likeK- to solve these and many other allied questions.
The high eccentricity of the orbits of some Double
Stars, including a Centauri, subjects the internal
constitution of the components to tlifferent pressures
at the times tif pcii-astron and ap-astron. Does
this affect their spectia in a measurable degree?"*

'■' Reference Cataii

igni- of Sonthern Doable Stars, page xiii a.

NERVES AND NERVOUSNES

By DA\"ID FRASER HARRIS, M.D., B.Sc. (LOND.)
^Lecturer on Pliysiulogy, Ciiii'crsify of rUnii iir^hitiii .)

Possibly no terms are so looseh' used as " nerves,"
and " nervousness." Owing to the prevailing ignor-
ance about the nervous svstem the\' have become of
much profit to the quack and the charlatan. Before
we attempt to understand in what " ner%'()usness "
consists, and wh\' some people are '" nervous "' and
others not. we should find out what a nervous system
does, what the possession of it means, and what would
be the result of our not having one. The central
nervous s\-stem is a mass of very highly specialised
living matter (nerve-cells) contained inside the skull
and spinal column in order to be protected from
injurN' from outside. Into and out of this mass of
nerve-cells run certain nerves from and to the
" peripherv," b\' which we mean all the b(>d\'
exclusive of the central nervous s\stem itself. Most
of the nerves going in, carr\- impulses which arouse
sensations, most of the nerves going out, carrv out
impulses which arouse movement : by the former
the environment acts on us. bv the latter we act on
the environment. The nervous s\stem as a whole
is the great means of communication between one
part of the body and another : without it we should
be totallv unaware of what was going on around us.
We should have no sensations and no pain :
although possessing eyes we should not see, though
having ears we should not hear : and, not ha\ing
an\- sensations, we should have no emotions and no
ideas, since these are higher mental states com-
pounded of the more fundamental states of sensation
and perception. Of course we should have no
memorv, as there would be nothing to remember.
Again, if we had no nervous system, we should not
be able to move a muscle when we wished ; no
matter in what danger we found ourselves we should
be powerless to escape from it. One part of the
bodv would not have the least idea where the other
part was. what it was doing, or what it wanted : we
should have no knowledge of the world around us or
of our relationship to it. We could initiate no
bodily activit\% and so would be powerless to make
any change whatever in the relations between the
environment and nursehes. lUit b\ means of the
afferent nerves the centres do receive information
regarding both the body and the outside world, and.
in consequence, the individual, through his centres
and efferent nerves, can constantly adjust his liody to
the changing conditions of the environment.

The management of an armv is a good analogy
with the working of the nervous svstem. The army
council — a few men — we ma\- liken to the highest
parts of the brain, the intelligence department and
signallers to the afferent nerves, the rank and file of
the soldiers to the muscles — tht- ultimate executants

of the orders issued by the council. >'ow the
soldiers, left to themsel\-es, w ould never of themselves
engage in any plan of concerted action. They !nust
be drilled, made to execute first independent and
then corporate movements in accordance with
definite orders, the meaning of which the}' have
previously learned. The men must be arranged in
squads, companies, regiments and battalions, and
must go through manoeuvres from time to time to
practise what would be required of them in actual
warfare. But in order that the army council issue
appropriate commands, it must be kept informed as
to the condition, number and distribution of all the
units constituting the army. The soldiers are the
muscles : if left to themseh'es, that is not attended
to b\- the central ner\-ous system, the}- might act
spontaneously from time to time, but not alwa\-s in
a manner calculated to promote the well-being of
the organism as a whole of which they form the
constituent parts. The luen must be drilled by
sergeants who take orders from junior officers, who
obey superior officers, who in turn obey orders
ultimately emanating from the council at the \\'ar
Office, indirecth". then, this council issues orders
to each indi\idual soldier in the army. Similarly
the brain is in touch with each muscle, which it also
drills and exercises and keeps in readiness for future
activity, a state we call "tone." The muscles, if
not in constant functional connection with the nerve
centres through the efferent nerves, woukl becotue
toneless, slack, unready to contract when a motor
impulse (command to action) arrived. Ikit the very
opposite is what we find : muscles duly inner\ated
have a certain degree of tension, are ready to shorten
after onl\- an exceedingly brief time from the instant

of receiving the message.

Muscles not thus
innervated, even though well suj^plied with blood
would not be in a perfect state of health, would
become "a law unto themselves," and therefore be
unrelated to their neighbours" needs. This unfailing
outflow of impulses from the cells of the central
nervous system to the periphery — to muscles, blood-
vessels, glands and possibly otfier tissues — is known
as innervation. Innervation really means being
attended to h\ the central nervous system : it is not
being given strength to do work, but it is being kept
in readiness to do work — a \cr\- different thing. It
is being neurallv supervised. Innervation is not the
commissariat : the blood supplies the food : the
blood is the canteen ; each muscle must absorb its
own nourishment, but b\- means of innervation it will
be constantl}- kept " up to the mark," drilled, made
tonic and read\- for action. Innervation is each
soldier"s knowing that those in authority over him

21

22

KNOWLEDGE.

January. T)11.

have not forgotten about him, that messages have
been duly sent out to order his food to be brought
into camp, that orders have been recei\'ed as to how
each minute of his day is to be occupied, and so on.
A command to action imparts no strength to act, but
it constitutes a necessary antecedent condition for
an attentive, well drilled soldier to obe\' on the
shortest notice in the best possible manner. This is
w hat tone does for muscles ; it keeps them readw
This outflow of what we may convenienth- call tonic
impulses has nothing to do with our consciousness :
although diminished in intensity, for instance, during
sleep, it is not abolished. We do not therefore
consciously or voluntarily innervate our muscles :
they are innervated subconscioush'. When the
nervous s\-stem dies the muscles take on the flaccidit\-
of death before they enter upon /-/^'o/' iiiorfis, the
rigidit\' of death.

Now we have a good deal of e\idence that the
outflow of these tonic impulses is rlnthmic or
intermittent, in other words at a certain regular rate
per second. Physiologists are not agreed as to the
exact rate of arrival of these at the muscle, but efforts
are being made to determine it. In what we call a
voluntary muscular contraction it is e.xtremeh'
probable that, although the intensit\- of these impulses
is very greatly increased, their number per second, or
periodicity, remains the same. The will, then, onh-
exaggerates the existing state of tone; this exaggerated
tone is a voluntar\- contraction, and hence it is
sometimes said that '" tone is incipient contraction "
— a very good description. We know that heat is
given out in voluntary contraction, but heat is also
produced by a muscle in tone : and in [)roportion as
the tone dies down so is the output of heat
diminished.

This unconsciously exerted tonic influence of the
nervous centres on the muscles is, like man\- other
things, best realised when it is temporarih- diminished
or done away with. Thus, when a man gets a blow-
on the head, is " stunned." or suffers a severe and
especially sudden injury, or has his central nervous
s}-stem badly poisoned b\- alcohol or chloroform,
he is quite unable to remain in a standing posture.
This shock, or collapse, is due to his muscles having
become more or less toneless, not so much because
the\- are poisoned as because their innervation is
reduced or abolished through the mechanical or
chemical damage to the centres emitting the tone-
maintaining impulses. The nerve-cells responsible
for sending out these tone-preserving impulses are
sometimes called " trophic centres," or centres related
to trophism, a Greek word meaning "growth" but
now taken as synonymous with tissue-health. Trophic
nerves for muscles are none other than the efferent
nerves conveying impulses inducing tone in the
muscles. Trophic impulses in any other sense, in so
far as muscles are concerned, do not exist.

All tissues, even such an apparently lifeless one
as bone (which, how^ever, is very much alive), when
from any cause deprived of their nerve-suppl\- suffer

in health, become atrophic, or atrojihy. It is equal!}'
correct to speak of blood-vessels and glands as being
kept in tone or in a good trophic state by reason of
their innervation. Thus, if the efferent nerve to an\-
tissue is cut. the tone of that tissue is diminished or
abolished for the time being, muscles become flabbv,
blood-vessels parah-sed or dilated, and glands quite
unhealth^•. It will be convenient to ha\'e a term for
the nerve-cell in the centre and its outgrowth, the
efferent nerve-fibre, which passes all the wa\' from
the central nervous centre to the periphery : it is
" the efferent neurone." Neurone means nerve-cell
and all its processes including the long conducting
process to the tissue or organ innervated. The
nerve-fibres which stretch from nerve-cells to tissues
have at least the propertv of conductivitv, the power
of conducting nerve-impulses. Toneless muscles are
a sign of deficient innervation, a condition seen for
instance typicalh' in melancholia. It is, of course, a
mental condition, but its outward and visible sign is
deficiencv of tone of all tissues not only muscles but
blood-vessels, glands, and skin as well. Deficient
innervation leads to deficient tone, whether that
deficient innervation is due to mechanical injury to
the nerve or to a depression of the emitting centre
itself. In neurasthenia, again. inner\'ation is deficient;
not onh' are the muscles lacking in tone, but the
glands, for instance the gastric glands, are deficient
in chemical tone, and as they do not secrete sufficient
h\'drochloric acid there results the consequent ner\'ous
d\'spepsia. Popularlv a neurasthenic is " a nervous
person"; stricth' speaking such a person is suffering
from weakness of the nerve-centres, probably due to
their being poisoned or not sufficiently nourished at
some previous time. Nerve-centres themselves, then,
can be in good health, full of vigour and nerve-energy,
or the\' can be less vigorous, putting forth less
energ\'. be definitely weak. Neurasthenia is onh-
Greek for ii(>t-sfren}>tli of nerx'es : but in this case
" ner\'es " means nerve-centres, since ner\'e-trunks
are not sources of energy and merely conduct
impulses. Nerve-energy or nerxous energy are terms
one reads about a great deal, sees very often used in
advertisements of quack niedicines, and so on; but it
is a thing of which the man of science has very little
knowledge. There must, of course, be such a thing as
nerve-energ\' ; else nerve-centres could effect nothing
and affect nobod\', for "ex iiihilo iiiliil fit." The
English physiological psychologist. Dr. MacDougal
of Oxford, has coined the word " neurine " as a
convenient term for nerve-force. Although we know-
almost nothing about nerve-force we know a little of
what it can do. just as, although we do not know-
much about electricity, we know something of what
it can do: both electricity and neurine pass from
places of high to places of lower pressure. Returning
to the centres in the spinal cord, we see that they
are the sources of the nerve-energy sent out to the
tissues everywhere; but we might at this point ask
ourselves: do we know anything of the material basis

of this ner\'e-energy .''
( To l>c continued I.

NOTES.

ASTRONOMY.

By F. A. Bellamy. M..\., F.R..A.S.

F.WE'S COMET (or 1910c' Cerulli). — The comet
announced as a discovery by Cerulli at Teranio Observatory,
on November 8th, by means of photo,t;raphy, proves to be a
re-discovery of the unexpected, or forgotten, return of the comet
discovered by Faye in 1S43. This comet is interesting as
having a short periodic orbit of seven and a half years, or
slightly less ; so that, since 1843, this is the ninth return, and it
happens to be a favourable one ; it is not always so, as at
some returns it could not be observed, notably in 1903. When
discovered on November Sth it was of the 9'5 magnitude.
After a few observations had been made, it was ascertained
by \V. F. Meyer and Miss S, H. Levy, of the Berkeley
Astronomical Department. U.S..-^.. that the elements of the
orbit which they computed resembled those of Faye"s Comet,
and they afterwards computed elliptic elements from observa-
tions of November 9th, 11th. and 13th ; they give the date of
perihelion passage as 1910, November 12"413, G.M.T., but
M. Ebell {Ast. Nach. 4456), deducing the time from
Professor Stromgren's elements for 1903. finds the date to be
October 23-747 Berlin M.T. In Ast. Nach. 4461, G. Fayet
has discussed the question both with new observations and
old elements, and he obtains November 2'2S3 Paris M.T. as
the date of passage, and the other elements are \ery close to
those which he deduces from Stromgren's work. Favet's

elements are

: —

T

=

1910 Nov. 2-28269.

Paris M.T.

u

=

199-^ 51' 6'-74

o

=

206° 7' 0"-31

t

=

10= 30' 24"-79

e

=

0-560806

log. a

=

0-575109

/'

=

4S6"-792

Thej' should, however, be regarded only as provisional.
Plenty of obser\ations are being obtained and they will pro\e
of use in the computation of a definiti\'e orbit.

Fayet has also deduced an ephemeris for Paris mean
midnight ; from a portion given here it can be seen that the
comet is now moving northwards and eastw-ards ; it reached
its most southerly declination on December 19th and 20th.
and at the end of this month it is about the same right
ascension as the Pleiades and twenty degrees south, and its
magnitude will be equal to half that at the time of

re-discovery.

1910-1911.

h.

K.A,

^.

D

ice.

Dec.

17 ..

3

39

13 .

.. +3°

9'-5

20 ..

40

15 ..

.. +3-

8'-5

25 ..

42

51 .

.. +3°

13'-9

30 ..

45

58 .,

.. +3=

27'-2

Jan.

4 ..

49

45 .,

.. +y'

47'-2

9 ...

54

11 ..

.. +4°

12'-6

,.

14 ..

3

59

10 ..

,. +4^

42'-3

19 ..

4

4

43 .,

.. +5°

15'-3

j^

24 ...

4

10

43 .,

.. +5°

50'-7

29 ...

4

17

12 .,

.. +6°

27'-6

HALLEVS COMET.— It is still possible for observations
to be obtained of this much-discussed comet. Those who wish
to see it again before 1985. should not lose the opportunity
during the next few weeks ; it is best situated for observation
about 5 a.m., and will be at a similar position about two and a
half hours earlier each month ; being at rather a low altitude
it may be seen more readily at places south of England. This
ephemeris is that given by F. E. Seagrave, in the Astronomical
Journal, No. 620.

Midnight G.M.'

1910.

Jan. 3

., 11

„ 19

„ 27

4

12

20

28

S

16

24

1

Feb.

Mar.

April

h.

11

11
10

10

51
44
36
27
17

6
55
44
34
24
15

7

27
53
57
51
44
56
49
44
6
15
25
49

-18" IS'-l

-18° 2.:-i

-18° 23'-9

-18" 10'-8

-17° 45'-6

-17° 8'-l

-16 19':2

-15 20'-5

-14° 14'-3

-13° 3'-7

-11° 5l'-6

-10 40'-7

ASTRONOMER ROYAL FOR SCOTLAND.— We olTer
our congratulations to Professor R. A. Sampson upon his
appointment to the position of Astronomer Royal for Scotland.
His works upon J. C. Adams and Jupiter's Satellites have
hitherto absorbed nearly all his time given to astronomical
work : both these memoirs are of great and lasting importance.
Now that he has charge of an observatory worthy of the name
and one with an excellent and efficient all-round equipment,
we look forward to a continuance and development of that
practical side of astronomy so ably inaugurated at Edinburgh
bv the newlv-appointed Astronomer Roval for England. Mr.
F. W. Dyson.

THE PRESENT STATE OF VARIABLE STAR
WCJRK. Introduction. — Exclusivism seems to be the
worst policy in scientific research. As observational science
is now highly developed in practically all the countries of the
world, and all the workers are exploring almost the same
borderland of discovery, accurate and e\er-renewed knowledge
of what others have done and are doing, is an absolute
requirement if unnecessary duplication is to be avoided,
as well as the waste of energy, time and money. This know-
ledge, howexer, is not always as perfect as it ought to be,
especially in great countries such as Britain, France, and the
United States, where scientific men. less inclined to inter-
nationahsni and to the study of foreign languages, are some-
times tempted to consider the scientific activity of their
countrymen as representing science. Small countries are
better able to avoid this drawback, for. lacking elaborate
sources of scientific information, forced to be polyglots and
naturally exempted from any undue chauxinism. their men of
science are in a better position to consider from an unbiassed
point of view the efforts of the whole of the scientific world.
And this, perhaps, is one of the reasons why countries, small
in their area and economic possibilities, maintain a high
standard of research among their powerful rivals.

In the peculiar field of astronomy in which I have been
engaged for many years — the study of those interesting objects,
variable stars — much correspondence with British amateurs
has shown me how often their \iews on this subject are
confined to English references. I therefore think that a
comprehensive statement of what is actually done in this
branch, in the whole world, may be welcomed by all
interested in the matter including those possessing a
telescope, whatever its size may be. It will not only gi\e
them an idea of the work of astronomers in this direction, in
different countries, but will also show them how the obser-
\ ation of changing stars is carried out with zeal and success
by isolated workers.

Statistics of Discovery. — Many complaints have been
made recently with regard to the great disproportion which
exists between the great number of variable stars known

23

24

KNOWLEDGE.

Jantarv, 1911.

at the present day and the attention shown to them. .A mere
. glance at a catalogne of such objects will make this perfectly
clear and illustrate how many, and e\en essential facts, remain
unknown : especially as to long period variables, which should all
be followed in a permanent manner in \iew of a better know-
ledge of their light- curves.

In order to bring this out more clearly, I ha\'e drawn up
a table of the disco\ery of ^•ariable stars during recent years.
For this, I deduced from a manuscript catalogue of such
objects, for each year during the last decade (1900-19091. the
mmiber of variables announced as being variable, and to
which a ■■ provisional number " has been affixed, together with
the number of the same stars that have received up to the
present a " final name " — a combination of two letters — as
explained hereafter, and the proportion between these two
series of figures.

Variables in clusters have not been included in the lists.
but novae or temporary stars have been, since thev are in
the A.G. lists they were considered as lettered. The
discovery at Harvard and at Heidelberg of a large number
of very faint \ariables accounts for such great totals as
that of 1904, for example, and I intended at first to exclude
them from the statistics; but, as the variability of several of
these objects has been confirmed and as they thus received
final names, I ultimately included them.

In dealing with the total number of " pro\isional \ariables '
care must be taken to exclude some " apparent " variables.
For instance 19.1900 Puppis is a rediscovery of / Puppis :
67.1901 and 74.1901 are /) Cassiopeiae and k Persei respectivelv.
and as they possess Bayer (Greek) letters, they will never
receive final names in the usual nomenclature, and have been
excluded: 2.1902 is a rediscovery of U Lacertae : 9.1902 and
43.1909 are the result of mistakes and never had a real
existence.

In the following table, the first column contains the total
(apparent) number of provisional numbers of variables as
shown by the Astroiiomischc Xachriclitcn: the second the
true or real number of discoveries; the third, the number of
variables which have been lettered up to the present (including
the latest list of the A.G. Committee in A.X. 4364); the
fourth, the number of variables still inilettered and of which,
therefore, little or nothing is known ; the fifth and final
column, the proportion between the real number of discoveries
and the lettered \ariables. The small number of lettered
variables in 1909 is of course partly due to the fact that they
had only been known a short time.

conducted by .Mr. C. L. Brook. F.R..A.S., an amateur himself,
a splendid and almost unique opportunity to achieve, with the
most simple appli.iiices, a mass of useful work, and to contribute

Year.

0)

Apparent
Number.

(2)

Real
Number.

(3)
Lettered.

(4)

Non-
Lettered.

(5)
Proportion.

1900
1901
1902

■903
1904
190S
1906
1907
1908
1909

29
99
23
86

283

171
194
223

175
46

28

97
21

86
283
171
194
223
'75

45

28
61
21

43
60

38

47

lOI

35
10

0

36

0

43
223
1.53

147

122

140

35

loo-o %

62-9
1000

50 0

21 -2

22 2
24 -2

45 3

20-0
22 '2

1900-09

1329

1323

444

879

33-6 "„

It will be seen that in recent years the proportion between
new variables and those that are more or less " settled " is a
little more than 20%, and that 66% of all the variable stars
discovered during the last decade still awaits confirmation.
This fact will appear more .strikingly still on the inspection of
Figure 1. where they ha\e been graphically represented.

If British amateurs will consider that their own countrv
offers them, through the medium of the "Variable Star
Section " of the " British Astronomical Association," so ablv

Figure 1.
The Discovery of \'ariable Stars.

The tliin line represents the number of vari.-ible slurs discovered each year since

1900 ; the interrupted line the number of the same stars whose variability has been

confirmed ; and the hea\-y line at the base, the proportion between both.

January, 1911.

KNOWLEDGE.

25

to our Unowledge of the mysterious laws which tjovern the
sidereal universe, I hope that some of them at least will .seize
this opportunity at once, and join the small band of observers,
to which I am proud to belong;, whose scientific activity is
greatly appreciated ; if not very fully in the British Isles,
at least elsewhere. ^^.^^^ ^^^^ ^^^.^

Honorary Secretary " Societc d' Astronomic d'Anvers."
( To be cQiitimicd.)

BOTANY.

By Professor F. Cavers, D.Sc.

SUSPENSOR IN FERN EMBRYOS.— It was recently
shown by Lyon that the enibr\'o of Botrychiiiiii obliqnuin
has a suspensor, while Campbell recorded a similar structure
in the case of Daiiaca. The interest of these discoveries lies
in the fact that hitherto a suspensor has only been known to
occur in the embryo of Lycopodiiiin and Sclaginclla among
the Fern Alliance, or Pteridophyta. Lang {.4//);. Bot.. 1910)
has just discovered that Hcliiiinfliusfachys, which is closely
allied to Botrycliiuiii. has a massi\'e suspensor liUe that of
the latter genus.

THE ECOLOGY OF CONIFERS.— The ecological
features of the Coniferae are discussed by Groom (Ann.
Bot., 1910), who sets out various problems relating to this
interesting subject. The main questions are : (1) the cause of
the .xerophytic foliage and tracheidal wood; (2) the cause of
the survival of Conifers in competition with Dicotj'ledonous
trees; (3) the cause of the suppression of various Conifers in
past ages. Stress is laid on the fact that all Conifers are not
xerophytic, in spite of their xerophytic leaf structure. Hohnel
showed that the Larch has a rapid transpiration current, while
Groom's experiments show that Coniferous wood, in spite of
its tracheidal structure, may conduct water with a rapidity
equal to that of a rapidly transpiring Dicotyledonous tree.
Another point is noted in this connection — the aggregate leaf
surface of a Coniferous tree may exceed that of a Dicotyle-
donous tree, because of the immense number of the leaves.
This leads to the view that the .xerophytic structure of the
Conifer leaf is actually necessary because of the great amount
of exposed surface, and the term " architectural xerophytism "
is suggested for xerophytism that is dependent, as in this case,
upon the organization of the plant rather than upon the direct
influence of external factors on the organs in question. The
extinction of many of the ancient Conifers is attributed to
their imperfect acclimatization, to the fact that they have a
large number of insect and fungus enemies, and to their
relatively slight power to react advantageously to new con-
ditions. At the same time, their " architectural " xerophytism
enables them to thrive in nearly all situations, from those that
are physically or physiologicall>' dry to those that are
sufficiently humid to permit the development of luxuriant non-
xerophytic forests.

"GERMANOL." — A Berlin syndicate has placed on the
market a product called " Germanol," consisting of an earthy
mixture containing about eighteen per cent, of calcinated soda.
The virtue of this mixture, which is intended for agricultural
use, is attributed by the manufacturers to an increased
porosity of the soil following an increase in the proportion of
carbon dioxide, the latter being supposed to act as a "fertiliser."
Mitscherlich (Landwirtscli. Jahrb., 1910) has made extensive
experiments, however, which appear to show that if this
mixture has any value at all it must be attributed to the action
of the carbon dioxide in increasing the solubility of difficultly
soluble substances in the soil. He concludes, moreover, that
increasing the carbon dioxide content of the soil does not
result in an increase of plant product ; that there is always
sufficient carbon dioxide in the soil already to render mineral
food available ; and that any increase in the solubility of soil
constituents due to increase on carbon dioxide content is

absolutely superfluous so far as any advantage to the plant is
concerned. It would seem, therefore, that "Germanol" will
pro\e a failure in practice, just as various other nostrums, like
" Nitragin " and " Nitro-bacterine," have done in the past.

BOTANY IN CALIFORNIA.— Some r;cent publications
on Botany issued by the University of Cilifornia are of
general interest. They include a beautifully iiinstrated paper
by Hall on ornamental trees, especially the "bottle-brush"
genera of the Eucalyptus order (Myrtaceae). Gardner
describes a new genus of Flagellafes (Leuvcnia) which is of
special interest in view of the importance attached to these
lowly organisms lying at the common base of the animal and
vegetable series. This new genus presents a remarkable com-
bination of characters which make it difficult "at present to
classify it, even to naming the family to which it belongs or in
which it has its nearest affinities." The nuclei and pigment-
bodies (chromatophores) are inconstant in number, while in
the motile phases contractile vacuoles occur at both the
anterior and posterior ends, while pyrenoids, gullet, and eve-
spot are absent. The same author also describes two new
genera of Green Algae which grow in association with other
marine algae of California. Endophyton grows inside the
frond of Red Algae of various kinds, and apparently forms a
link between the families Chroolepideae and Chaetophoreae,
differing from the latter in the absence of hairs. Pscudo-
dictyon, referred to Chroolepideae, grows among the cells of
the cortex in species of tangle {Laminaria).

CHEMISTRY.

By C. Ainsworth Mitchell, B.A. (Oxon.), F.I.C.

ACTION OF POISONOUS ALKALOIDS ON
PL.ANTS. — .\i\ instructive series of experiments has been
carried out by Messrs. Otto and Kooper {Landw. Jalirb.,
1910, xxxix, 397) to ascertain the effect of adding dilute
solutions of poisonous alkaloids to the soil in which plants are
grown. It was found that when a relatively small area of
soil was treated daily with a solution of strychnine sulphate,
the liquid first filtering through the soil contained the acid
constituent of the salt, but not the alkaloid, though this, too,
eventually passed through the soil unchanged. This phenom-
enon of temporary absorption of the alkaloid was also
observed in the case of perfectly sterilised soil, and was thus
not due to bacterial action. The presence of solutions of
salts of alkaloids, such as strychnine, in the soil had a pro-
nounced effect upon plants growing therein, checking both
germination and growth, and causing the fruit to be abnormal.
Nicotine added in the fonn of a three per cent, solution was
retained by the soil, apparently through the formation of
a loose "addition compound," for the alkaloid was not altered
chemically by the absorption. Eventually a portion of the
nicotine was decomposed and volatilised, this being apparently
brought about largely by the influence of heat and moisture in
the soil. The growth of the tobacco plant was greatly stimu-
lated by the addition of nicotine solution to the soil, and the
proportion of nicotine in the plant showed an increase. The
alkaloid had a similar, though less pronounced, effect upon the
growth of the potato, and did not appear to affect the com-
position of the plant. Treatment of the soil with a solution of
sodium nitrate had a similar stimulative action upon the
growth of the tobacco plant.

THE GLA2ING OF ANCIENT GREEK VASES.— The
nature of the black glaze upon a Greek vase excavated at the
Heraeum has been examined by Mr. W. Foster ijoiirn. Aincr.
Chcin. Sac, 1910, xxxii, 1259), who has found that it does not
contain manganese, but consists of an iron compound,
probably ferrous silicate. The red glaze upon a Mycenian
vase has also been examined, the surface of the vase being
scraped with a diamond, and an analysis made of the resulting
powder. The conclusion drawn from the results is that the
colour of the glazing is due to the presence of a ferric
compound.

26

KNOWLEDGE.

January. 1911.

Analyses of the body of Mycenian vases showed that they
contained from approximately 41 to 48 per cent, of silica,
17 to 20 per cent, of alumina, 7 to 9 per cent, of iron oxide.
14 to 20 per cent, of lime. 4'5 per cent, of magnesia, about
3 per cent, of potassium oxide and about 5'5 per cent, of
carbonate. From these analyses it appears that Mycenian
pottery differs from Attic and Campanian pottery in containing
much less silica but much more lime, and in the relatively
large proportion of carbonate present. Owing to its low
proportion in silica the pottery can be readily melted at a
relatively low temperature.

THE DIGESTIBILirV OF BLEACHED FLOL'R.—
Of the numerous methods that have been proposed for bleach-
ing flour, only those in which nitrogen
peroxide is employed as the bleaching agent
have proved successful upon a commercial
scale. Flour bleached in this manner is now
largely sold, and on more than one occasion
has been the subject of actions in the law
courts. Hence the experiments of Mr. E. \V.
RocUwood upon the effect of bleaching
upon the digestibility of flour ijouni. Biol.
CJicni.. 1910, viii, 3271 have a special
intei-cst at the present time. In these
experiments the tests were applied simul-
taneously to bleached and unbleached
samples of the same flour, the conditions in
each case being strictly parallel. It was found
that uncooked gluten separated from the flours
was digested by pepsin with equal rapidity in
each instance, while the product from the
bleached flour was digested more readily by
pancreatin than that from tlie unbleached
specimen. The cooked gluten from the
bleached flour was more easily digested
both by pepsin and pancreatin than that
from unbleached flour, while bread made
from the two kinds of flour did not differ in
its digestibility, the nitrous compound having
been expelled during the baking. The bleach-
ing process was also found to have had no
appreciable influence upon the digestibility of the starch in
the flour.

THE MEKliK BURNER. — A new gas burner, presenting
many advantages over the ordinary Bunsen burner, has been
put upon the market by the Cambridge Scientific Instrument
Company, under the name of the Meker burner. The con-
struction of this is sliown in the accompanying figure, from
which it will be seen that the holes for the admission of air
are much larger than in the Bunsen burner, so that the
mixture of air and gas in the chimney is of the right proportion
for complete combustion. A deep grid of nickel is screwed to
the top of the burner to prevent the flame " striking back."
The flame of this burner is homogeneous, and does not show
the inner and outer cone of the Bunsen flame. Its temperature
is much higher than that of the latter, and is nearly uniform
throughout. In fact, the coolest part of a Meker flame is
hotter than the hottest portion of a Bunsen flame. A burner
of modified form has been made for use with compressed air,
thus enabling a yet higher temperature to be reached.

FXONOMIC BIOLOCY.

By Walthr E. Collinge, M.Sc, F.L.S., F.E.S.

HOUSE FLIES AND DISEASE. — I promised last
month to deal with some of the correspondence I have
received with reference to house flies as transmitters of
disease. A renewed interest, I am pleased to say, has been
awakened in the subject, and, as I recently stated. I trust the
public will ultimately educate the authorities in order that our
different public bodies will realize the seriousness of the
matter. No one wishes to create a scare, or to indulge in

Pion of nickel qf'd C

wild unguarded statements, but to calmly and judicially
consider the facts as brought out by recent investigations.

FLIES IN WINTER. — One correspondent inquires what
becomes of the flies in winter, — do they die, leaving eggs to
hatch later, or do they hibernate? Mr. F. P. Jepson has
shown iJoKi-n. Ecoii. Biol., 1909, vol. iv.) by marking flies in
the summer of 1908, for purposes of identification, that
nearly all of them were captured in a bakehouse, the supply
continuing up to nearly the middle of November, when a
sudden sharp frost seemingly caused their sudden disap-
pearance; they reappeared, however, on February 15th, 1909.
From these and other experiments he concludes that during
the winter flies may be found where the conditions — tempera-
ture and so on — are favourable, and
^ that they will breed in the winter. Many

undoubtedly persist throughout the winter
as adults, and appear to be more hardy
and longer lived than those taken in the
summer.

IRE 1.

er Burner

I H !•: SPREAD (IF INFECTIVE
niSE.\SES. — The belief that flies may
carry the germs of difterent diseases dates
back to the sixteenth century, but actual
experiments proving this are of much more
recent date. Experiment has now actually
demonstrated that the following diseases
can be disseminated by the agency of house-
flies : — Anthrax, cliolera. ophthalmia, tuber-
culosis and typhoid fever. In addition to
these there are a number of diseases which
ai"e probably carried by flies, but the
evidence, as yet, is incouclusixe.

There is now evidence sufficiently clear
to show that, apart from disseminating the
germs of the above diseases, flies also carry
the eggs of parasitic worms and various
species of fungi.

Professor Nuttall very pertinently re-
marks (Local Government Board Report,
No. 10, 19091: — "It should be remembered that a fly
may cause relati\el\- gross infection of any food upon
which it alights after having fed upon infecti\e substances,
be they tvphoid, cholera or diarrhoea stools. Not only
IS its exterior contaminated, but its intestine is charged
with infective material in concentrated form which may be
discharged undigested upon fresh food which it seeks.
Consequently, the excrement voided by a single fly may
contain a greater quantity of the infective agents than,
for instance, a sajuple of infected water. In potential
possibilities the droppings of one fly may. in certain circum-
stances, weigh in the balance as against buckets of water or
of milk."

PROGRESS OF THE WORK.— Our grand-parents would
ha\e laughed at the idea of attempting to control such ubiqui-
tous pests as house-flies ; indeed, there are still people who are
unconvinced as to the seriousness of the part these insects
play in every-day life, as is instanced by many of the letters I
have received during the past two months; but, thanks to the
excellent work that is being carried out at Cambridge and else-
where, it will not be long before the public are not only
convinced, but they w^ill make themselves heard for drastic
alterations that will tend to minimise the danger.

Dr. Monckton Copeman has recently scheduled (Local
Government Board Report, No. 40, 1910) the work that is
being done at Cambridge, which includes special attention to
the elucidation of the question as to the range of flight of
flies, both in horizontal and vertical directions ; and under
varying conditions, meteorological and otherwise. Trials are
to be made of the respective value of various baits for
attracting and killing flies. The so-called lesser house-fly.

Janl-arv. 1911.

KNOWLEDGE.

27

Hoiiialoiiiyia canicitlaris. is to be studied. Dr. Graliaiu-
Sinitli will continue his work on the e.xperimental infection of
flies with pathogenic micro-organisms, whilst Dr. Nicoll will
inquire into the possible agency of flies as carriers of the eggs
of parasitic worms, and so on.

These are a few of the lines of research and experimentation,
all of which will increase our knowledge and place us in a
more able position to effectively deal with a pest we can well
aftbrd to be without, and one in dealing with which the general
public can materially assist.

GEOLOGY.

By RussKLL F. GwiNNELi., B.Sc. .A..K.C.S.. F.G.S.

WIND .-WD WAT1:R. — Quite a number of papers
published within the last few months deal with such subjects
as the movements of wind and water, and the resulting aeolian
and aqueous deposits.

In "The Origin and Growth of Ripple Marks" iProc. Roy.
Soc. A.,Vol. l.xxxivl. Mrs. .Ayrton describes experiments leading
to the conclusion that there are three ways of originating sand
ripples under water. Two of these methods are capable of
originating and then extending regular ripple- marks wherever
water is oscillating over sand, whether its surface be smooth
or uneven to start with. These are : —

(1) The "Differential Motion" Method, by which single
ridges arise at the loops of stationary wa\es.

(21 The "Brush" method, whereby the brushing action of
the vortex in the lee of any existing dune or obstacle
sweeps up a new ridge beside it, leaving a hollow
along the neutral line of the vortex.

The third method, depending on an initial uneven surface,
could, unaided, give rise to irregular ripple-mark only, since
it consists in piling up sand in places where the surface
chances to be uneven.

Summarily the processes by which mounds of sand are
built up under the action of stationary waves are : —

( 1 ) Ripples alwa\'s first form at places of maximum longi-

tudinal motion of the water, i.e., at places of constant
level.

(2) Smooth spaces are left at and near the places where the

water has no longitudinal motion, i.e., where the

change of level is greatest.
(31 liach set of ripples grows into a mound having its centre

plane at the place of maximum longitudinal velocity

and its lowest parts close to places where the

longitudinal motion is zero.
(41 There are therefore two of these mounds to each water

\va\e.

Mr. -A. Wade, B.Sc, F.G.S., in the Geological Magazine
September, 1910, deals with "The Formation of Dreikante
in Desert Regions." These curious three-edged stones, so
characteristic and abundant in most desert regions, are shaped
somewhat like a Brazil nut. The old explanation of their
fluviatile origin has long been discarded in favour of an aeolian
origin, which supposes that the wind I laden with sand and
thus a powerful eroding agent) strikes the point of the pebble,
glancing off on either side so that the " keel " on the upper
surface of the pebble is in the direction of the wind. If this
is the true explanation, it is difficult to make it tally with
observations recently carried out by the author in the
Egyptian Desert.

Thus he finds that the Dreikante are equally pointed at both
ends; collecting over three hundred specimens in an area of
about three hundred acres, he finds 78% set with the " keel "
appro.ximately at right angles to the wind; the keel instead of
being a simple straight one is often curved or even bifurcating
at both ends, giving a five-faced solid instead of a three-faced
one ; the faces are parabolic cur\es ; finally, actual experiment
proved that these three-edged stones ccjuld not remain with
their pointed ends facing a strong current of wind.

The author, therefore, shows that the travelling sand-grains
hit not edgewise but broadside on a face ; and being projected
off again in an upward direction, the parabolic cur\e is

produced. The cutting-away continues until the pebble
stands on a very narrow base, and then topples over ; thus the
erosion commences again on a fresh surface. " Sometimes at
night the rattling of the pebbles moving under the action of a
high wind is very considerable."

In the November issue of the same magazius is printed a
summary of the views of the Russian geologist, Iv. ':,enko, as to
aeolian deposits. He classifies the various types of stratifica-
tion in aeolian deposits (such as ripple-mark, diagonal
stratification w-ith opposed dips, horizontal, vertical, and so on),
and their modes of origin. In addition to ordinary winds the
action of whirlwinds can often be distinguished by the spiral
or circular arrangement of the dust particles. The dimensions
of particles of desert dust transported by the wind diminish
from the centre towards the margins of the desert. The
grains of sand have special characters in aeolian and in
aquatic deposits ; in the former they are characteristically
triangular.

Finally, we may note two papers by Mr. A. R. Horwood, of
Leicester Museum, on " The Origin of the British Trias."
One paper was read before the British Association in
September last, the other before the Geological Society on
November 23rd. The general view of conditions in Triassic
times is that the deposits appear, on the whole, to have been
laid down under conditions similar to those which now prevail
in the dry interior of continents. The lower-lying country
between the mountain ranges was covered by wind-blown
sand and alluvial deposits washed down from the hills during
occasional floods, and gradually the mountain-chains were
more or less completely buried. In hollows in the nearly level
plains that were thus produced, the water collected and was
evaporated, forming lakes of brine. (See Lake and Rastall :
"Text Book of Geology," 1910).

Mr. Horwood, however, considers the British Trias to be a
delta deposit, in which desert conditions did nothing more
than locally act upon the rock. They had no part whatever
in the icorl; of deposition. Among many other points, he
notes that ripple-mark affects only the sandstones, and not the
marls ; also that, whereas all varieties of desert sand agree in
possessing the texture of miniature pebbles with a highly
polished surface, all Trias sediments exhibit an eroded surface.

He maintains that there is positive, direct and accumuLative
evidence to prove that the Trias as a whole (and not the
Bunter only) was the work of rivers which had continued to
bring sediment in one form or another from the north-west of
Britain more or less continuously from the close of the marine
phase of Lower Carboniferous times.

THF ORIGIN OF CORAL ISLANDS.— Reef-building
corals can only thrive in seawater which does not exceed
about thirty fathoms in depth, and the temperature of which
never falls below 20" C. (68° F). The latter limitation almost
restricts coral islands to tropical seas ; the former implies a
shallow submarine foundation in every case. The explan-
ation of the occurrence of such shallow foundations or
submarine plateaux, far from continental land, has been more
or less of a mystery right down to the present day. The fact
of the existence of the plateaux is established, and also that
the material is frequently volcanic ; in other cases the living
coral is founded on an enormous thickness of dead coral rock
(as at Funafuti, where a boring of over a thousand feet
encountered nothing but coral limestone).

The curious atoll-structure, where a ring of coral islets
more or less encloses a central lagoon, renders the explanation
more difficult. The main theories are those of Darwin,
Dana, and others, on the one hand, and of Murray, Agassiz,
on the other. Darwin's hypothesis necessitates subsidence
of innumerable islands, the corals growing upwards on a
talus-slope of their own debris as fast as the islands sink.
This implies widespread crustal subsidence. In Murray's
eyes the submarine platforms are volcanic islands denuded to
a " plain of marine erosion." and the conditions are those of
general elevation or long-continued crustal repose.

R. A. Daly, writing in the American Journal of Science
(November, 1910) on Pleistocene Glaciation and the Coral

28

KNOWLEDGE.

January, 1911.

Reef Problem, explains the phenomena of coral islands as
being due neither to crustal subsidence nor to elevation of
volcanic islands^ but to changes in the sea-level itself.
These changes, broadly treated, consisted in a lowering of the
water-le\el, followed by a return to normal conditions as the
great ice-caps first grew to enormous dimensions, and then
retreated during the Great Ice Age. Estimating the Polar
ice-caps during the glacial epoch at an area of six million
square miles, with an average thickness of three thousand to fi\e
thousand feet, the author points out that the removal of this
water would of itself lower the general sea-level by one hundred
and twenty-five to two hundred and eight feet (say twenty to
thirty-five fathoms). Besides this, however, the gravita-
tional attraction of this great mass of ice would heap up
the ocean water nearest it to such an extent as to lower the
equatorial sea-level another five to eight fathoms. Thus the
total lowering of sea-level in the tropics would be (|nite thirty
fathoms. Conversely, the deglaciation of the wliolc ice-cap
would raise it to this extent.

Now. the submarine plateaux on which coral reefs are found
do not, as a rule, depart very much from an average of about
thirty-fi\e fathoms below present sea-level. Allowing for a
"veneer" of coral detritus, etc., of ten to fifteen fathoms in
thickness, the " solid rock " is about forty-five to fifty fathoms
under water. The uniform ity of the plateau level is explained
by neither Darwin's nor Murray's hypothesis: the present
author explains it as being due to marine abrasion during the
Glacial Period. Allowing for the thirty fathom lowering of
sea-level produced by the Polar accumulation of ice, this
platform would then be within fifteen to twenty fathoms of
the surface, a depth in whicli the iiroictli uf the earal
organism is possible.

If the whole earth were chilled during the Glacial epoch (as
supposed by some) reef"building corals would be vastly
restricted in areal distribution. A fall of six degrees only
would enormously diminish the area where the marine
isotherms never fall below 20° C, the temperature necessary
to coral life. This would mean that most of the present
areas of coral seas were then free from such life. As the
retreating waters caused low Pleistocene islands to emerge
from the sea and no coral fringes protected the loose volcanic
or calcareous material, denudation would be very rapid.
Exposed on all sides to abrasion by the open sea, these islands
would lose substance at least as fast as the chalk cliffs at
Dover are doing (about three and a half feet per annum). At
this rate the Chagos Bank, now a huge plateau, sixty miles
broad by ninety miles long, could have been reduced to the
Pleistocene sea-level in about fifty thousand years ; and the
whole duration of maximum glaciation in Pleistocene times was
much longer than that. Moreover, in the case of many areas
this Pleistocene denudation was only the " finishing touch " to
subaerial denudation, which might have been continuously
going on previously. Some of the volcanoes, indeed, may
have been not merely pre-Tertiary, but even pre-Cambrian.

Amelioration of climate followed, allowing coral life in the
waters where shallow platforms were now prepared for them.

At the same time deglaciation caused a gradual deepening
of the sea. The coral growth would easily be fast enough to
keep the living zone of coral within twenty fathoms of the sur-
face during this deepening. The mechanism of growth, with the
resulting development of atoll, barrier and fringing reef forms
would be analogous to that imagined by Dai win on the
subsidence hypothesis.

The theory of a general lowering of sea-level in inter-tropical
seas — counteracted in higher latitudes by the glacial attraction
— in no sense excludes complications due to local warpings of
the earth's crust. Other processes invoked by previous
writers have been so far neglected in the argument because
of the high probability that neither basin-foundering, nor
sedimentation, nor absorption of water by weathering rocks
seem to have been important enough since Tertiary times to
affect, by more than a fathom or two, the changes of level
assumed.

METEOROLOGY.

By JOH\ A. Cl'RTls. F.R.Met.Soc.

The week ended November 19th, opened with extremely
unsettled weather in all districts, with heavy rain, snow and
sleet. Thunderstorms and hail were reported on several days.
In the South, however, there was a decided improvement in
the second half of the week. Temperature was below the
average everywhere, by as much as 7° in places, while
sunsliine was. on the whole, in excess. In Ireland and in
Scotland W,, the amount of rainfall for the week was below
the average, though the number of rainy days were in excess
there as elsewhere. The mean temperature of the sea water
was higher than that of the air on all our coasts, the excess at
Plymouth being 10°. The highest temperature reported was
5S° at Geldeston on the 15th, the lowest 18° at Marlborough
on the 1 7th.

The week ended November 25th, was cold generally, but
the weather was finer in the Southern and Eastern districts
than in the Northern and Western. The defect in temperature
exceeded 9° at several stations, and at Prestwich it reached
10 . -At three stations in Ireland there was a slight excess.
The highest temperature reported for the week, 59°, was in
Ireland on the 23rd. The lowest minimum was 10° at
Balmoral on the same day. In Westminster the highest
reading was 43°, and the lowest 25''. The amount of rainfall
varied much. !n the English Channel it was three times the
average, and in Ireland S. nearly twice as much, while in
Scotland N, it was not quite half as much as usual. In the
tlastern districts generally the rainfall was in defect, and at
Spurn Head the week was rainless. Sunshine was in excess
except in the Southern districts. Balruddery reported the
highest aggregate, 22'7 hoars or 43 %. The mean temperature
of the sea water ranged from 53°'0 at Teelin to 40°'0 at
Pennan Bay.

The week ended December 3rd, was, as a rule, dull and
unsettled, with frequent and long-continued rains. In the
extreme North, however, and in Ireland, the weather was
bright and cold. Aurora was seen in Scotland on November
29th and 30th. Temperature was low everywhere, the defect
exceeding 7 in places ; the highest reported reading was 56°
at Jersey on the 27th, the lowest 19°, at West Linton and
Markree Castle on the 30th. Rainfall again varied greatly, it
being only one-fifth of the a\erage in Scotland N.. while in
the Midland Counties it was five times the average. Falls of
1-in. and upwards in twenty-four hours were frequent, and at
Raunds in the four days, December 1-4, the total precipi-
tation was 4"23-ins. .Sunshine was in excess of the average in
Scotland N., and in Ireland N., but in no other district. At
Jersey the total duration for the week was only 5'8 hours
(10 %), while at Castlebay it was 33'4 hours (67 %). In London
the week was sunless. The mean temperature of the sea
water was greater than that of the air on all our coasts. The
individual readings varied from 53° at Plymouth, to 40° at
Cromarty.

The week ended December 10th, was dull. niiUl and wet.
with a good deal of strong wind. Temperature was high
everywhere, the excess exceeding 6 at several places. The
highest readings reported were 57 ' at Cirencester on the 7th,
and at Llandudno on the 9th, the lowest, 29°, at Balmoral and
at Arlington. Over a large part of the kingdom the tempera-
ture of the air did not fall below the freezing-point, and on
the ground the minimum was only 25°, at Balmoral. The
rainy days were in excess of the average, and at many stations
rain was measured each day. The amount of rainfall was,
however, not excessive, except in England S.W., where it was
nearly twice as much as usual. In some districts, indeed, the
rainfall amount was in defect, and in Scotland N. it was but
little more than one-third of the average. Sunshine was
scanty in all districts. At Westminster the total duration was
only \'i hours (2 %) while the highest amount reported was
only 13'5 hours (25 %) at Felixstowe. The temperature of the
sea water \aried from 52 at Plymouth to 3'1 at Cromarty.

January, 1911.

KNOWLEDGE.

29

THE AUTUMN OF 1910.— For Meteorological purposes
the Autumn is taken as the three months, September. October,
November, and of the thirteen weeks. September 4th to
December 3rd, 1910, in England S.E., four weeks have been
unusually warm, eight weeks unusually cold and only one
week about normal. During the same period five weeks have
been classed as weeks of heavy rainfall, four as weeks of light
rainfall and four weeks as normal. The sunshine in five
weeks has been abundant, in six weeks scanty, and in two
weeks normal.

THE S.E. TRADES AND RAINEALL.-
Dr. W. N. Shaw called attention to
a remarkable apparent relation between
the strength of the S.E. Trades, as
recorded at St. Helena, and the
rainfall in England, and the suggestion
then made has stimulated research
in various directions. In a paper just
published in the Quarterly Journal
of the Royal Meteorological Society.
Mr. J. I. Craig, of the Egyptian
Weather Service, expresses the opinion
that .a distinct connexion has been
traced between the winds at St. Helena
and the Rainfall in Northern Africa.
If this opinion is confirmed on further
investigation, it will be of great
practical importance ; for the Nile
flood depends on the rainfall in
Abyssinia and the adjacent regions,
and any reliable prognostication of
the probable Nile' flood should be
of immense advantage to Egypt.

SNOW IN JOHANNESBURG.—
Mr. H. E. Wood, in a paper in the
South African Journal of Science
for September, says: " On the morning
of August 17th, 1910. the town of
Johannesburg, for the first time in
its history, was covered with snow
to a depth of several inches. To
many of its inhabitants, particularly
the younger generation, the sight of
snow was quite new. The result
the unusual event was
bv a general holidav in

-Some vears ago

was that
celebrated
the town."

Figure 1.

Thyrcosthcniiis bioi'atus, male. Front view

of head showing cephalic prominences and

extraordinary arrangement of eves.

MICROSCOPY.

By A. W. Sheppard, F.R.M.S..
with the assistance of the following niicroscopists :

Arthur C. Bankield.
James Burton.

The Rev. E. \V. Bowell, M.A.
Charles H. Caffvn.

Arthur Earland, F.R..\I.S.
Richard T. Lewis, F.R.M.S.
Chas. F. Rousselet, F.R. M..S.
D. J. ScouRFiELD, F.Z..S., F.R..M.H.

C. D. Soar, F.R.M.S.

A MVRMECOPHILOUS SPIDER iThyreostheniiis
hiovatus). — A good deal of interest always attaches to the
heterogeneous assemblage of creatures which for some reason
or other are permitted to spend their existence, or part of their
existence, in company with xarious species of ants, and a few
remarks, therefore, concerning a small spider somewhat
notorious in this respect, may not be altogether out of place
here.

Many species of spider have been, at one time or another,
recorded as having been found in ants' nests, but. upon careful
investigation of their claims, only three of our British spiders
can be considered to be really myrmecophilous. namely.
Tetrilus arietinus, Evansia merens, and Thyreosthenius
biovatus. It is easy to comprehend how mistakes are liable

to arise in this matter. Manj' small souicrs are found under

stones, or amongst the vegetation grov^-irj.; against the sides of

pieces of rock ; and when the protecting I 'dy is turned over

it is the simplest thing in the world for the . oider to drop into

a nest of ants should there be one undernt h Spiders, too,

are often captured apparently wandering upc the surface of

the nest of the wood-ant {Formica rufa); ;'it it will be

noticed that it is usually in the case where a la^ . : nest has

been disturbed, and the surviving ants have coiu^lructed a

comparatively small nest upon the summit of the damaged one,

leaving a bulk of uninhabited material upon which intrudiiig

creatures may venture with some amount of safety. In several

such instances in a wood in the North

of London I have found large numbers

of a small spider (Tiso vagans)

actually living amongst the debris of

,^ - the nest, but in no case were the

spiders found in the central portion

where the nmch-persecuted ants still

held their own. It would, however,

have been extremely easy to have

fallen into error, especially as the nests

were of a lighter and more friable

character than is usually the case, and

it was consequenth' by no means easy

to decide where the inhabited portion

ended and the debris commenced.

Thyreosthenius hiovatus is, in the
male sex, a most grotesque and striking
creature; but, on account of its small
size, its peculiarities are hardly visible
even to highly trained eyes, unless a
lens be employed. The female, on
the other hand, is a most ordinary
looking creature, and indistinguishable,
except by careful microscopical exam-
ination, from quite a number of allied
spiders. Both sexes, even when fully
developed, are of a somewhat pale
colour, and convey the impression of
immaturity.

The only species of ant with which
they associate appears to be the wood-
ant {Formica rufa). So far as I am
aware the reason for their presence in
the nest is quite a mystery. It seems
pretty clear that they do not feed upon
the ants, which are in size and fighting
capabilities vastly superior to them ;
and it seems unreasonable to suppose that they destroy the
various small creatures which the ants harbour as sca\engers
or pets. Still, the so-called intelligence of the ant has been
enormously exaggerated, and it is not beyond the range of
possibility that the spider may be fooling its hosts, and
perchance making meals at the expense of their offspring
when the nurse's back is tiu'ned. When the nest is disturbed
the spiders do not feign death, but generally extricate them-
selves from the debris and are quite easily seen. Isolated
specimens are occasionally found wandering at some
considerable distance from any nest, but, so far as I have
been able to ascertain, not in an\' district where the wood-
ant does not occur. As a rule the males appear to be
considerably rarer than the females, but it is quite possible
that, as in the case of many other spiders, the life of the
adult male is a short one.

In some of the very restricted pine areas of south-east
Sussex, during the early part of October, specimens of
Thyreosthenius are sometimes to be found in the small
newly-formed nests which are plentiful where larger nests
have been destroyed bv the gatherers of " ants' eggs." These
nests vary considerabK' in character, some being ver\- rich in
pupae and others being almost devoid of anv but adult ants.
It is a curious fact that I have never found a single spider in
a nest where pupae were very numerous. At the season
mentioned, namely, early October, the majority of the captures
were males, and almost all of these, as well as the females,

30

KNOWLEDGE.

January. 1911.

had only just attained maturity. I am unable to report on the
contents of these small nests early in the summer as they were
not then in existence. Large nests, however, examined in
May, contained, on the testimony of local collectors, a
comparatively large number of females, the males being stated
to be very rare in the adult state.

Dr. Randell Jackson, who has kindly forwarded me a
northern specimen of this species, also reports a great
preponderance of females amongst his captures. A detailed
description of the spider would be out of place here, but the
following characters will suffice to distinguish it from its
allies : — Eyes small and very widely separated ; front row-
straight by their bases in female, by their centres in male.
Posterior eyes strongly procurved (in the male this row of eyes
is distorted by the exaggeration of the caput). Legs fairly
long. Femora, each with two rows of bristles on the under-
side. Tibial spine very small, close to base of joint.
Metatarsi I. II and III with sensory bristle; in III it is
just beyond the middle; in I it is about two-thirds from the
base. Tarsi not much shorter than metatarsi ; somewhat
fusiform, especially in the male.

The species most likely to be confounded with
Tliyrcosthciiiiis biovatiis is Pepuiiocraniuni ludicrum,
which agrees with it pretty closely in size and general
appearance, and which possesses, in the male sex, a some-
what similar cephalic protuberance. It occurs also in pine
and heath districts, and is not uncommon in many parts of
the South of England. The specimen purporting to be a male
Tliyrcvsthcniiis. presented to the British Museum by Mr.
Donisthorpe, is, in reality, nothing but Pepoiiocraninin

'"'!''''■"'"■ F. P. Smith.

QUEKETT MICROSCOPICAL CLUB.— November 22nd,
mfo, Mr. E. J. Spitta, L.R.C.P., Vice-President, in the chair.
A paper on "A Water Mite new to Britain {Xeiituania
triangularis, Piersig)" contributed by Mr. Geo. Plant Deeley.
This genus was formerly called Cochleophorus. and several
species are described under this generic name by Mr. C. D.
Soar, in Science Gossip. June, 1900. The locality from
which Mr. Deeley obtained his specimens was Parkhill.
Stourbridge. Both sexes were taken. — Mr. T. B. Rosseter,
F.R.M.S.. on "'A new species of .Avian Tape-worm
{Hynienolepis npsilon)." He found it in January, 1910.
parasitic, amongst the faeces of the intestine of a Wild Duck
{Anas boschas). The author gave an account of its
affinities, references being made to the work of Schilling
(1823), Creplin (1829), Dajardin, Pagenstecher I1S5S). Pfaff
and Olrix, and Krabbe (1867). A full description of the
specific characters of the new species was given, and from the
similarity of the uterine sac to the Greek small i\ the name
upsilon was bestowed on it. — Mr. James Burton on Botrydinni
grannlatuni. "The plant consists of small green balloon-
shaped vesicles about three millimetres in diameter. Below
the surface of the mud an extensive root system is produced ;
the roots branch dichotomously and extend to a considerable
distance, often reaching a length of six millimetres. As the
plants very often grow thickly side by side, the roots are
entangled and interlaced in the mud, and, the whole
plant being of somewhat tender consistency, it is difficult
to extricate perfect specimens. The upper part, when
young, is filled with protoplasm and is bright green in
colour. Later the centre becomes more watery and
the green is seen to be due to finely granular chlorophyll.
The colourless roots are filled w'ith watery protoplasm. .As to
its classification. Professor West classes it with the group
Heferokontae. All the older books put it among theSiphoneae,
and it seems, for several reasons, to be very appropriately
placed there. One of the interesting facts connected with
Botrydinni is that, although it is of such considerable size, it
is unicellular. In thinking of a unicellular organism — plant
or animal — we usually consider it as something very small,
or even microscopic, in size ; but that is not necessarily the
case. The Siphoneae are a class grouped together because
of the noticeable characteristic that they are all unicellular,
notwithstanding whicli. most of them are of considerable size.

The best-known member of the group is the exceedingly
common Vanclieria. There are many species — some terrestrial,
and found on the damp earth of flower-pots and on damp
garden-paths: others occur in ponds. In these plants, though
they reach a length of several inches, and sometimes nearly a
foot, no dividing-walls appear in the filaments under normal
xegetative conditions. Most of the family are marine and
one genus — Cff;(/t'r/>(T, occurring in the Mediterranean — reaches
a length of several metres, and yet is only one cell.

Mr. Herbert F. Angus, of the firm nf H. F". .Angus & Co..
exhibited and described a number of Microscopes by
R. Winkel. of Gottingen. who, he said, enjoyed a high
reputation in Germany, although almost unknown in England.
He pointed out that the model was of the more or less
stereotyped Continental pattern, inclining more to the Zeiss
model than any other, but diftering in several important
details, as was only to be expected in the productions of an
old-established firm who had given proof of their originality in
the past by first employing fluorite in the construction of
objectives, and producing an objective with a hyper-
hemispherical front lens.

A ROCK GRINDING MACHINE FOR AMATEURS.—
Nearly everj' amateur microscopist who has taken up the
study of petrology has at some time felt desirous of preparing
thin sections of rocks for himself instead of purchasing them,
but has in a good many cases been deterred by the labour
involved in grinding them by hand. This method will answer
the purpose if only a few slides are required, but when he
takes up the matter seriously and wishes to make large num-
bers of sections the student finds the necessity of having some
mechanical means to minimize the work.

The professional lapidaries' lathes, and also the special rock
slicing and grinding machines placed on the market for
petrologists, are generally speaking far more expensive than
the average amateur can afford, and I therefore wish to
describe a home-made apparatus which has been found to
give good results, and to be fully capable of doing the work
for which it was devised.

Figure 2 gives a general view of the entire machine, and
Figure 1 shows the top of the table and the way in which the
various parts are disposed.

The cost of this machine complete is. roughly speaking.
17s., and it can be made by anybody capable of using
ordinary tools.

Tlie apparatus is erected on an ordinary sewing machine
table, which can be procured very easily. For the slitting
disc, which is shown on the right hand side of Figures 1 and 2,
it is necessary to get an ordinary polisher's lathe head. This
is threaded at one end to take a circular saw or emery wheel,
and upon this thread is run the cutting disc, which is then
bolted on in the same way as a circular saw. I use a plain
disc of soft iron six inches in diameter, and about one-fiftieth
of an inch thick.

The rock-holder is the most elaborate part of the arrange-
ment, but is quite simple to manufacture. Figure 3 is a
near view of this on a larger scale. It consists of a
spindle six inches long, an upright to carry the same, and the
jaws to hold the rock. Four and a half inches of this spindle are
three-eighths of an inch in diameter threaded sixteen to the
inch, and the remaining one and a half inches are a quarter of
an inch in diameter, and threaded to take the cones of an
ordinary bicycle pedal. This spindle was made for me by a
working cycle maker. It is carried on an upright cut out of
oak three-quarters of an inch thick. This has a threaded plate
screwed on each side of it. through which the spindle moves.
There is a lock nut on the spindle behind the upright to hold
it rigid. To the end of the spindle are attached the jaws for
holding the rock. This portion consists of a piece of oak
three quarters of an inch thick, three and a half inches long by
three inches wide. To the bottom of this is screwed a piece
of oak a quarter of an inch thick, and on top of this is a
moveable piece which is clamped on the rock by the butterfly
nuts of the two three-inch bolts.

The upright portion of the jaws is fastened to the spindle
by the ball bearings of an old bicycle pedal. When the

J.WUARV. 1911.

KNOWLEDGE.

31

machine was first made this bearing was plain, and consisted
of a nut and washer behind the upright of the jaws and
another nut and washer in front, and these were simply
screwed together. This worked fairly satisfactorily, but stuck
somewhat when tightened sufficiently to pre\ent shaUe, and
the bicvcle pedal bearing was substituted. It will be seen
that the jaws, if properly adjusted, swing on the ball bearings
parallel to the cutting disc, and the rock can be mo\ed
forward for cutting another slice by turning the spindle
toward the operator.

A disc of brass one and three-cjuarter inches in diameter is
fixed to the left hand end of the spindle as a handle for
turning it by, and this is graduated into four equal divisions
for reference.

In order to get the rock-holder to swing strictly parallel
with the cutting disc, some adjustment is necessary, and this
is arranged by bolting the upright carrying the spindle to the
table. The bolt in front is a fi.xture, but the one in the rear
goes through an elongated hole in the table, so that the upright
can be swung on the front bolt as a pi\'ot until the jaws are
parallel, and then the back bolt is clamped up tight.

The rock is kept against the cutting edge of the disc by
the chain and weight attached to the rock holder at the bottom
corner. This can be seen in the
illustrations.

The grinding lap is a cast iron disc
eight inches in diameter, half an inch
thick in the centre, with the top siu'face
bevelled off to three-eighths of an inch
at the edge. A lead or copper lap can
be used instead of the cast iron one.
but I find the latter is quite satis-
factory and is cheaper to purchase.

The spindle for this lap is made
from an ordinary half-inch bolt, si.x
inches long, procurable from any
ironmonger. This requires cutting
down until it is about four inches long,
then it has to be centred, and made
with a cone at the bottom end and a
cup at the top. A pulley wheel is
fixed at the bottom of this spindle to
take the driving band. Two nuts are
wanted for the top of this spindle, one
of which is screwed up tight for the
lap to rest on. and the other to fasten
it by. The bearing for this spindle
under the table is a screw with a cup
in the end, which is fixed with a couple
of nuts through a threaded plate. This
plate is attached to a piece of wood
affixed to the underside of the table.
The top bearing is a screw with a cone point which passes
through a threaded plate into the top of the spindle. This

—ia

Figure Z

Figure 3.

Figure 1.

screw is adjustable for taking up wear and is securely fixed
by the lock nut. All this can be procured from a small cycle
maker at a very reasonable price.

The carrier for this top bearing con-
sists of a block of wood seven inches
long by three inches high by two and
a half inches wide, and this is securely
screwed to the t.able from underneath.
Upon this is a piece of oak three
quarters of an inch thick, seven inches
long by three inches wide, to which is
screwed the threaded plate for the
coned screw of the bearing.

This method of fixing has been
found quite satisfactory. It is per-
fectly rigid, and there is no shaking or
jumping of the lap, even when driven
at the highest speed obtainable.

It will be seen that the drive for the
slitting disc is taken direct from the
(hiving wheel, but that for the grind-
ing lap goes over two jockey pulleys
so as to get the horizontal move-
ment. These jockey pulleys are
ordinary iron pulley wheels \\ ith
screw ends, such as are used for
cirrying blind cords.

It is necessary to ha\e two leather
or gut bands, and these have to be
changed when altering from the slit-
ting disc to the grinding lap.
A piece of tin. shaped like a bicycle mud guard, is fixed to
the table behind the slitting disc to stop the splashes. A tin
tray is also placed below the table under the disc to catch the
waste carborundum and water, which can be used o\er again.
Round the grinding lap I use a cake tin, which has had a large
hole made in the bottom for the spindle and pulley wheel to
pass through. A ledge of tin is soldered all round this hole to
keep the water, and so forth, from the bottom bearing.
These mud guards are not shown in the photographs.

This apparatus has been in use now for about three years,
and has ground between four hundred and four hundred and
fifty slides during that time. It has given the greatest
satisfaction to me. and although, no doubt, it is not so good as
a professionally made machine (with which, of course, it is
not intended to compete), it will be found a very useful article
for the amateur petrologist. who usually has far more
enthusiasm than he has money. p tt r^ppyN

KCJVAL MICROSCOPICAL SOC I FTV.— November 16th,
1910, Professor J. Arthur Thomson, M.A., F.R.S.E., President,
in the chair. In connection with the gift of two slides of
Plcicrosigina. the Hon. T. Kirkman. the donor, asks whether
fresh-water Pleurosigmae with oblique striae are rare.

32

KNOWLEDGE.

January, 1911.

Mr. M. J. Allan, of Geelong, sent a slide of spicules of a species
of Gorgonia unknown to him concernins the identification of
which he sought information. He also sent some slides
mounted in fluid iiy a method of his own. He likewise
mentioned in a letter that four years ago he had devised a
variable eye-piece giving three magnifying powers, which he
offered to send for inspection. Mr. Merlin sent, for exhibition,
three photomicrographs of Gravson's Rulings, which Mr.
Grayson had sent'him. They showed the 100,000. 110,000,
and 120.000 bands of Grayson's twelve-band plate. Previously
no photograph had ever been exhibited of anything o\er
112.595 lines to the inch. Dr. Butcher exhibited a number
of photomicrographs of diatoms, Coschiodisciis astcroin-
plialus and C. omphalanthus, Navicula Smithii. Pinnii-
laria cardinalis and Triceratiuin favus. The photographs
were taken in series and represented successive focal planes
of each object. The conditions under which they were taken
were given.

Mr. A. F,. Hilton exhibited a number of nmunted specimens
of British Mycetozoa. In reference to liis exhibit he said that
at the present time the disposition was to classify the
Mycetozoa among the Rhizopoda, but their metamorphoses
marked them off as an entirely distinct group. Their life-
history presented three principal phases — aquatic, amoeboid,
and aerial. The question of the sexuality of the Mycetozoa
was a very obscure one. In all three phases there were
nuclear divisions.

The President made a communication on Japanese
Pennatulids, and exhibited some typical specimens of great
beauty. He said that he had been entrusted ijy Professor
Ijima, of Tokyo University, with a collection of Pennatulids,
on the study of wliich he was at present engaged. His report
was not yet ready for publication, but he had thought that it
would be of interest to the Fellows of the Society to see a
representative sample of these beautiful Sea- Pens. They
would understand, when they looked at the dimensions of the
specimens, why it was necessary on a long railway journey to
be content with a sample of the collection.

The Pennatulacea, or Stelechotokea. include some of
the most beautiful of fixed marine animals — long graceful
colonies, often plume-like, as their name suggests, with rich
colouring, and with strong luminescence. They live fixed on
the floor of the sea, and many of them show a famihar
adaptation to life on the bottom — long stalks raising the
polyp-bearing portion off the substratum. In deep-water
forms, such as the beautiful Umbellulas, the proportion of
sterile stalk to polyp-bearing rachis reaches an extreme.

The Pennatulids were related to Alcyonarians, such as Dead
Men's Fingers, Precious Coral, Organ-Pipe Coral, the Gor-
gonids and the Gorgonellids, like HicksoncUa, which Mr.
Simpson had established as a new genus at the last meeting of
the Society. They differed markedly, however, in several
respects. In a very remarkable way the primary polyp,
which developed from the fertilized egg, was sacrificed to
forming the main axis on which the secondary polyps were
borne, which in turn might give off (always through the
intermediation of stolons or solenia) tertiary polyps and so on.
A central rod. which was present in the majority as the skeletal
support of the colony, ran up the middle of the gastric cavity
of the primary polyp, and some authorities regarded it, there-
fore, as endodermic in origin, whereas the skeletal support of
all related forms is ectodermic. Thirdly, the Pennatulids
almost always showed a pronounced dimorphism — along with
the ordinary polyps or autozooids there were dwarf polyps
without tentacles, the siphonozobids, whose office it was to
keep currents of water going in the canals of the colony.
It should also be noted that there was in Pennatulacea a
marked tendency to bilateral arrangement of the polyps, similar
to the arrangement of barbs on a feather.

The President also read two papers by Dr. J as. F. Gemmill,
(1) "Aerator for small Aquaria," (2) "Adaptation of Ordinary
Paraffin Baths for Vacuum Embedding." Mr. J. E. Barnard
read papers " On the Use of a Metallic Electric Arc in
Photomicrography," and on "A Simple Method of obtaining
Instantaneous Photomicrographs."

THE EFFECT OF GRAVITY ON EUGLENA VIRIDIS
EHRB. — At the Meeting of the Royal Society held on
November 17th, Harold Wager, F.R.S., gave the results of
some experiments on the movements of micro-organisms.
Eiiglciia viridis, when placed in the dark in shallow vessels
or narrow tubes, becomes aggregated into network-like patterns
or more or less well-defined circular groups. If a narrow tube
filled with water containing sufficient Euglenae to give it a
pronounced green colour be placed horizontally in the dark or
in a weak light, the aggregation takes the form of a series of
nearly equally spaced groups like green bands crossing the
tube from one side to the other. Each group shows clearly
two distinct regions, a central denser one consisting of
cells moving downwards, and a lighter peripheral area
consisting of cells moving upwards. There is, in fact, a
constant cyclic movement, which is kept up so long as the
aggregation persists. Examination with a pocket lens shows
that, as the organisms reach the bottom of the stream, they
gradually separate from one another, and begin to move
upwards. As they reach the upper surface, they are seen to
be drawn towards the central denser region of the group,
and again enter the downward stream. This aggregation, with
its regular cyclic movements, may persist for several days,
provided the t'uglenae are kept in the dark or under red glass.

The downward movement appears to be a purely mechanical
one, dependent upon the specific gravity of the organism, and
is not due to a stimulus which evokes a physiological response
as in geotropism or geotaxis. The upward movement is, on
the other hand, due partly to the activity of the organisms
themselves, partly, no doubt, to the currents set up in the liquid
by the friction of the downward moving stream. The upward
movement of Englcna appears to be controlled, so far as the
orientation of its elongate body is concerned, by the action
of gravity.

The network-like aggregations and groupings resemble ver\-
closelv the cohesion figures which are formed, under certain
conditions, when fine sediment is allowed to settle slowly in a
■ 'uid, and the conclusion has been arrived at that the
r.,gregations are probably of the nature of cohesion figures,
due to the action of gravity upon organisms massed together,
combined with the vortices set up by the streaming movements.

The movements of certain micro-organisms are therefore
controlled in a purely mechanical fashion, and the advantage
to those species which, like Eiiglcna, are often found in a
confined space in large numbers, must be very great, as by its
means a constant circulation is maintained, and they are
prevented from accumulating in such dense masses as would
be detrimental to their existence by interfering with their
assimilatory or respiratory functions.

PHOTOGRAPHY.

By C. E. Kenneth Mees, D.Sc.

INFRA-RED PHOTOGRAPHS.— .A recent holiday trip
to Portugal gave me an opportunity of trying some landscape
photographs taken by infra-red light after the manner
suggested by Professor R. \V. Wood.

A filter was prepared which passed only light abo\e
7,250 A.U., and through which, therefore, only a ver.\' faint
amount of deep red light could be seen by screening the eye
thoroughly.

The plates which were used had a sensitiveness extending
with long exposures to 7,600, so that the region used with the
plates and screen was situated between the a and A lines, from
7,250 to 7,600.

The nniltiplying factor of the screen on these plates was
found to be about three thousand, so that, as a normal
exposure at F. 8 in sunlight would have been about one-tenth
of a second, the infra-red photographs required an exposure
of five minutes.

Unfortunately the peculiarities of the Portuguese small boy,
and the very limited time at my disposal, tended to cut

January. 1911.

KNOWLEDGE.

33

Figure 1.

A \ie\v from the great Bridge o
in Oporto.

exposures too short ; but some of the results obtained proved
of considerable interest.

Two t\'pical examples are reproduced herewith. The first
is taken from the great bridge o\er
the Douro, in Oporto, and shows
well one of the most striking features
of all these photographs — the in-
tense blackness of the blue skw
(See Figure 1.) Even the faintest
trace of cloud stands out at once
against the blue sky when observed
by infra-red light, so that it would
seem possible that the method might
be of considerable use to the meteor-
ologist. The shadows in infra-red
light are extraordinarily deep, show-
ing no detail at all if the sky be clear.
because the blue skylight contains so
little light of long wave length.

The second photograph, which is
taken in the Avenue Liberdad, in
Lisbon, shows the extraordinary
appearance of foliage under this
infra-rei. light. The chlorophyll
has but che slightest absorption for
it, so that the foliage on the trees
appears white, while in the left-
hand bottom corner we have the
curious phenomenon of a white
palm 1 (See Figure 2.)

Incidentally, it is interesting to
remember how few coloured sub-
stances do absorb infra-red light
between seven thousand and eight
thousand .A.U. The only two dyes
which I know to absorb completeK-
in this region are Naphthol Green
and the new Hoechst dye, Filter
Blue-Green. The new Badische

Anthraquinone dyes absorb to seven thousand fi\e hundred
but transmit light of greater wa\'e length ; nearly all other
blue and green dyes transmit
red light of wave length seven
thousand or under.

AX "EXPLOSION" THE-
ORY OF THE LATENT
IMAGE. — In a letter to The
Brifisli Journal of Photo-
^rapliy. Mr. F. F. Rci.'.vick
makes a suggestion for a new
theory of the latent image, though
various facts pointing in the
same direction have been pub-
lished at intervals. This theory
is based on the observation of
Dr. \V. Scheffer, that a silver
bromide grain on exposure,
\iolently throws off a part of its
substance, rupturing the surround-
ing gelatine in its passage.

Mr. Renwick suggests that, in
an emulsion, the silver bromide
grains are wrapped round by a
tangled meshwork of gelatine,
and can only be attacked either
through the extremely minute
channels left, or by diffusion
through the substance of the
gelatine skeleton. Now, if Dr.
Scheffer's observations be
accepted, then in the neighbour-
hood of an exposed grain the
densely tangled network is broken
through, and channels of relatively
large size, giving far readier access

C. L. Kenitt-llt Mas.

n the Donro

J-ri'irt ail t nj r tt-na piiOiO^ttJl^

for the developer to the silver bromide grains, are formed.
In some respects this theory seems :j be more satisfactory

th;in any hitherto held. It has general';,- been assumed that
the commence. nent of development
depended upo; 'he provision of a
nucleus, upon \> ;?h the silver pro-
duced by the interaction of silver
bromide with the vsducer could
precipitate. This remiiins probable,
but a difficulty was that, in this case,
once fogging from an u.iexposed
developer had commenced, it should
have proceeded at the normal rate.
This does not seem to be the case ;
if measurements be taken . of the
increase of fog with time of develop-
ment for an unexposed plate, it is
found that the function obtained is
similar to that given by an exposed
plate, but with a much lower velocity
constant.

This is accounted for at once if
the exposed grains have literally
become " exposed "' to the attack of
the developer, by blasting passages
through their surrounding network.
This explosion theory is also
\aluable in that it enables one to
give a meaning to the " ripening "
of an emulsion. A "' ripened " grain
would be one which was in the most
explosive state : that is, in which
the crystallisation occurring during
cooking had reached the limit of
stable equilibrium, so that any
further access of energy would
result in its disintegration.

The theory is certainly fascinating
in its possibilities, though it will have

to face much criticism, especially from a consideration of the

destruction of the latent image by oxidisers, and of the

desensitising action of some
metaUic salts, when added to
the emulsion.

PHYSICS.

By W. D. Eggar, M.A.

THE CAVENDISH LABOR-
.ATORY. — On Saturday, Novem-
ber 1 ith, a large and distinguished
company assembled at " the
Cavendish " to do honour to Sir
J. J. Thomson, whose twenty-five
years of office as Professor of
Experimental Physics have been
signalized by the publication of
the ■■ History of the Cavendish
Laboratory." The Vice-Chancel-
lor presided, and Dr. Glazebrook,
of the National Physical Labora-
tory, presented a specially bound
copy to his old friend and former
chief. Few institutions possess
a more distinguished record than
this Cambridge Laboratory, young
as it is. James Clerk Maxwell
was appointed as first professor
to the newly constituted chair in
1871. The Laboratory, built
under his directions, was opened
in 1874. When Maxwell died,
in 1879, Lord Rayleigh succeeded
to the post, which he held until
1885. [^j. J.jThomson, then a very

t,h h- C. E. KviiiuHi .l/<-,-:

Figure 2.
The Avenue Liberdad in Li.sbon.

34

KNOWLEDGE.

January, 1911.

youns man, was the third professor, and uiidt'r him thoCa\ en-
dish has, to quote Lord Rayleigh, assumed the first place
among physical laboratories. Not only the professor's own
researches, but the ^spirit with which he has animated the
band of students who have thronged to him at Cambridge,
have spread the fame of the laboratory throughout the civilized
world.

SCIENCE .4ND ENGINEERING.— Sir J. J. Thomson,
in a presidential address to the Junior Institution of E.ngineers,
pointed out that the distinction between Physics and Engineering
is one of aim, and not of method. It is the Engineer's
business to turn to practical account the advances made by
the Physicist. But the latter must by no means concern
himself with utility, ^o man can foresee the significance of a
new discovery ; and it would be disastrous to the progress of
Engineering if men of science were to confine their researches
to matters of obvious utility, .'^t the same time England is still
behind Germany in the way in which new discoveries are seized
upon and applied industrially. For example Professor Dewar
invented a flask for holding liquid air. A form of this is now
sold in large quantities as the "Thermos" flasli, and used for
keeping tea and other forms of refreshment hot (or cold). But
none of these flasks are made in England. A well-known
example of the German faith in pure scientific research exists
in the Jena glass industry, which owes its foundation to the
patient and thorough investigations of Abbe and Schott.

ZOOLOGY.

By Professor J. .Arthur Thomson, M.A.

HABITS OF THE WOMBAT.— J. A. Kershaw got two
living wombats iPIiascolninys iirsiiins} from Flinders Island
in Bass Strait, and kept them alive in the National Museum.
Melbourne. They took fresh grass and thistles readily, and
allowed themselves to be handled. One of them had a young
one in the pouch, which emerged in fifteen days. But it did
not survive long. " In habits these animals remind one of the
Rodents, their manner of feeding and (juick side-to-side
movement of the jaws being very similar. They are very
quick in their movements when excited or alarmed, and
run with greater speed than one would expect from such
an apparently awkward animal. When touched, especially
near the hind quarters, they have a peculiar habit of
kicking violently backward with both hind feet. This, it was
noticed, occurred even when approached by its companion.
If annoyed, they do not hesitate to use both teeth and claws."
A peculiarity not before noticed is their habit of closing their
claws on the rough under surface of the paw so as to grasp
pieces of grass and the like. They spent most of the day
.sleeping, partly buried in their bedding.

SPERMACETI ORGAN.— E. Danois has studied this
curious organ in the whale, called Kogia hrcviccps, and finds
that it closely resembles that of the cachalot. He finds
corroboration of the view of Pouchet and Beauregard that
the spermaceti organ is a dependence of the right nostril, and
equivalent to a mucous gland in other toothed Cetaceans,

such as the dolphin. If so. we have another illustration of ,1.
frequent evolutionary method — making an apparently new
organ by a transformation of a very old one.

W'.XSHING OYSTERS. — Fabre-Domergue has made an
interesting series of observations at Concarneau. which should
serve to justify scientific methods in the eyes of the world, for
they concern the oyster. He has shown that oysters may be
kept for eight days (or even for a fortnightl in filtered water,
frequently changed, without losing any of their virtues, but
gaining rather. The micro-organisms which are apt to linger
in the mantle cavity, with deleterious results to the oyster-
eater, can be thoroughly washed away by the filtered water,
and the oysters do not lose in weight, nor in their power of
" \ital resistance," nor in " embonpoint." Their market
value is unaffected, and we can swallow them with a lighter
heart.

COLOUR SENSE OF HIVE-BEES.— John H. Lovell
has made an experimental contribution to a much discussed
question : — "Do Hive-bees distinguish colour as such ?" The
results of his experiments strongly support the conclusion that
bees distinguish colours. They are more strongly influenced
bv a coloured slide than by one without colour, and when
they get accustomed to visit a certain colour they tend to
return to it habitually. They stick to their colours. But
" this habit does not become obsessional."

ARE THERE BLACK CORALS IN THE NORTH

SEA ? — Messrs. Freeland, Fish Merchants, .-Aberdeen, recently
presented to the .Aberdeen University Museum a beautiful
Antipatharian, or Black Coral, with two thick irregular
branches o\er a yard in length, and with a basal diameter of
nearly an inch ! They got this from a trawler, which reported
finding it some fifty miles off Aberdeen. Such records must
be taken ctiin grano salts, for the sense of accuracy varies
greatly in its degree of development, and mistakes may arise
without any intention to play a trick on the innocent
naturalist. Many of the trawlers make long voyages nowadays,
a specimen may be passed from hand to hand, and invention
may be called upon to supply what memory has lost. On the
other hand, the specimen is rather an awkward one to carry
about, and a secure record in 1908 of a large Antipatharian
{Parantipathes larix) from the north-east of the Faeroes
makes one more inclined to admit that the locality reported
may be accurate. Unfortunately, the beautiful ebony black
axis is polished from end to end, and there is not a trace of a
spine, far less of a polyp ! Secure specific identification is
almost impossible.

COLOUR IN DEEP WATER.— Frederick Chapman
has called attention to the occurrence of deeply coloured tests
of the Foraminifer (Polytrema miniaceum), at a depth of
five hundred and seven fathoms. The species inhabits
relatively shallow water; the specimens from five hundred and
seven fathoms showed the characteristic rose-pink colour. It
may be recalled that one of the results of Sir John Murray's
1910 Expedition is to extend the light limit. Distinct traces
of light were detected at fi\ f hundred fathoms.

REVIEWS.

ASTRONOMY.

The Romance of Modern Astronomy. — By Hector
M.\CPHERSON, JUN'R. 334 pages. 39 illustrations and diagrams.
7T-in. X 5:i-in.
(Seeley & Co. Price 5/-.)

This volume is one of the series published by this firm under
the title of " The Library of Romance." We do not welcome
works of romance in astronomy, preferring books dealing more
with hard facts and less with romance and supposition,

leaving such as these to be supplied by the readers. However,
in the present instance, we do not find fault with the book,
only with the title, for the author has written an entertaining
book, and we like his way in which he records, in a pleasant
and accurate manner, most of the great and well-known
astronomical discoveries of the past four hundred years, as
well as some of the Grecian discoveries. We would
scarcely consider it as a text-book or book of reference
for an observatory library, though a copy should be in
all observatories ; but few astronomers, and none of the

January. 1911.

KNOWLEDGE.

35

jjeneral folks who love to read about astronomy, should fail
to read, better still, acquire, this book. It is a book well
suited for municipal and lending libraries, which mainly exist
for e.xciting and stimulating a reader's interest in a subject.

The printing is clear and on light, thick non-surfaced paper ;
there are thirty-three chapters, and more than a dozen
excellent plates, reproduced from photographs by Max Wolf,
Puiseux, Janssen, and Lowell ; there is also a good index.

B.

Ball's Popular Guide to the Heavens. — Third and Revised
Edition. 96 + xii. pages. 84 maps.

(George Philip & Son. Price 15 - net.)

We are glad to see this indispensable volume kept to the
fore, by a third edition five years after the second edition.

In 1892 Sir Robert Ball, greatly aided by the present
Radcliffe Observer (Dr. A. A. Rambautl, who formed two-
thirds of the seventy-two plates, besides a large portion of the
seventy-two pages of letter-press and index, wrote the first
edition of this guide, then called An Atlas of Astronomy ;
that work consisted of seven chapters of text, which preceded
the seventy-two plates. In the second and third editions a
small number of these maps, chiefly of planets and comets,
have been omitted or superseded by later work, and we find
such names as Barnard, Ritchey, Hale, Campbell, Keeler, and
so on, supplementing or replacing work by Common, Green,
Roberts, Henry, Proctor, and others ; astronomical progress
demanded these changes. So that the changes result in a
volume of eighty-four maps and ninety-six pages of letter-press
in nine chapters.

The maps which were not included in the first edition, are
chiefly those of the nebulae, comets, and sun. .An important
change, and an improvement upon the first edition, is in printing
the maps of the tracks of the planets and the star maps upon
a blue ground.

The maps are for the most part so excellently reproduced
and cover the ground of astronomy so well that it is difficult to
know where to find fault. But there are a few faults to which,
in view of a fourth edition, we draw attention, as they have
already been reprinted from the second edition. On page 13,
Saturn's rings "are now (1903)." This is incorrect; the
sentence required re-writing; page 17, a misprint for shadow-
patch, also wrong in second edition ; page 60 and other pages,
deceased astronomers are sometimes referred to as " late,"
sometimes not ; page 62, we think the number of stars in the
Astrographic Survey Catalogues will be nearer four millions
of stars than two millions, and the year (1903) is wrong. We
also notice on page 54 that the maximum magnitude of Nova
Geminorum is given as seven ; it should be five, or even
brighter, and an important omission occurs in the list of new-
stars, Janson's discovery in Cygnus in 1600; again on page 6.
referring to Halley's comet, the author says " and its next
return in 1910 will be awaited with very great interest." This
was correct for the second edition of 1905 ; it is rather
unfortunate that this should not have been corrected in the
present edition, knowing that Halley's comet had come and
gone five months ago, and that a frontispiece of this comet is
given. Considering the many beautiful photographs of the
comet which have been taken by Curtis (Lick Observatory),
at the Cordoba and other favoured observatories, it is also to
be regretted that this comet's beauty should be so depreciated
and so unfavourably compared with the January comet by the
drawing given. In future editions we would like to see
reproduced the binary star information as in the first edition,
but in a popular guide possibly that would be out of place ;
also a photograph of Halley's comet and some of Hale's
beautiful solar work. The distribution of the text among the
plates is a step in the right direction, and more appropriate to
such works. May this volume reach many more editions and
maintain its high character as a book which is needed in the
obser\ atory and in the astronomer's library.

F. A. P..

BOTANY.

.4 Text Hook of Botany.— By J. M. LovvsoN, M.A., B.Sc.

Fifth Edition, Re\ised and Enlarged, 607 + vii. pages.

Illustrated. 7-in. X ; -in.

(W. B. Clive. Price .-5.)

Although written specially to meet the lequirements of
students reading for certain examinations, this work has
decided merits, which have led to its being used extensively
by botanical students. As a handy and concise compilation,
published at a moderate price, it can be recommended to all
who wish for a single book to serve for reference, as well as
an introduction to more detailed works dealing with the
different branches of the subject.

The present edition differs from its predecessors n^ainly in
containing a large amount of m.atter which has been taken
from the works of Professor Cavers, published by the same
firm.

Plant hife in .Alpine Sicitzerland. — By E. A. Newell

Arber, M.A., F.L.S., F.G.S. 355 pages. 48 plates.

30 figures. 8i-in.X5-in.

ijohn Murray. Price 7 6 net.)

The wild flowers of the Alps, so numerous and so brightly
coloured, cannot fail to attract the sununer visitor. He
gathers them, and finding them very different from the flowers
of his own country, seeks to know their names. To aid him
in this, there are a thousand books with gaudily coloured
pictures, but should he desire to go a step further and find out
something of the life histories of these flowers, and why they
differ so markedly from the flowers with which he is familiar,
there are very few popular books to which he can turn for
guidance.

The volume now before us is in no way a flora, and very
little is said as to the identification of the plants described.
The introductory chapter deals with points in the structure of
two of the best known of .\lpine plants, the Alpenrose and the
Edelweiss. Typical flowers of the meadows, pastures, rocks,
marshes and forests are next discussed, and their special
adaptations to the regions in which they are found, and to one
another, are explained. The last chapter is given up to a
discussion on the afiinities and origin of the Alpine flora. A
glossary of botanical terms, some notes on the structure of
the flower and a bibUography form an appendix.

It has clearly been the object of the author to make the
whole book abundantly intelligible, even to those without the
slightest botanical knowledge, and in this he has succeeded
well. If we must criticise we would almost suggest that in
the first chapter the intelligence of the reader is perhaps a
little insulted, that even too much water is added to the milk.
The book is well illustrated by some excellent diagrams and
there are some forty-eight plates, reproduced from photographs,
some of which are exceedingly good. There was clearly a
definite need for a book of this sort, and we feel that the
present volume is admirably adapted to meet it.

GEOLOGY.

Smithsonian Miscellaneous Collections. Vol. 56. No. 5.
.4 Preliminary Study of Chemical Denudation. — ByF. W.
Clarke, Chief Chemist, U.S. Geological Survey. 19 pages.
No. 6. The Age of the Earth. — By G. F. Becker. 28 pages.
(Smithsonian Institution).

Dr. Clarke's paper is occupied with a revision of those
geochemical data which are used in the discussion of some of
the larger theoretical problems of geology. On the basis of
the vast amount of material accumulated by the Hydrographical
Department of the U.S. Geological Survey, a new estimate is
made of the amount of matter carried down by North
American rivers in solution to the sea. For the United States
the revised denudation factor is seventy-nine metric tons of
dissolved matter per square mile of drainage basin per year.
Revised estimates are made as far as possible for South
.American, European African, and .\sian rivers, but the data

36

KNOWLEDGE.

January. 1911.

for most of these are still very defective. Tlie composition
of the matter thus carried to the ocean is discussed, and a
special study is made of the factors used in Professor Joly's
method of estimating the age of the ocean by means of the
sodium content. Using Dr. Clarke's new figures. G. F. BecUer
attaclis the problem of the age of the earth by Joly's well-
known method. The chief new point introduced by Becker
is that the increment of sodium to the sea during geological
time has not been uniform but asymtotic. He conceives that
the Archaean and massive igneous rocks which supply the
great mass of the sodium originally occupied a far larger area,
and were thus more exposed to denudation than they are now.
Consecjuenth- the supply of sodium to the sea tends to suffer
an asymtotic diminution with the lapse of time. With the
new considerations and the revised data, the age of the ocean
is now estimated at between 46'0 and 74'4 millions of years.
The data for Lord Kelvin's method are similarly revised, and
a final estimate of fifty-five to seventy millions of years for
the age of the earth (starting from the consistciitior stntus\
is arrived at. limits not differing greatly from those found by
Joly's method.

PHYSICS.

The Principles and Mctlioiis tif Gcunictriccd Optics. —

By James P. C. Soi'thall. 626 pages. 170 illustrations.

9i-in. X6-in.

iMacniillan & Co. Price 25 - net. I

The Germans have taken possession of the great province
of .Applied Optics. The remarkable theoretical work of
Petzval, Seidel. and Abbe, together with the svstematic
investigation, undertaken and carried through by Abbe and
Schott, of the " optical properties of all know n substances
which undergo vitreous fusion and solidify in non-crystalline
transparent masses," has led to the establishment of the Jena
" Glastechnisches Laboratorium." Not only so, but until
quite recently there has been no English treatise on Optics in
which any reference to the later German theoretical work
could be found. This book is a very successful attempt to
supply the deficiency, and it is likely to be found indispensable
as a book of reference. After a chapter on the fundamental
laws of Optics, the characteristic properties of rays of light
are considered, such as the principle of the shortest route,
with an account of Sturm's theory of astigmatism. Then
follow Reflexion and Refraction at plane surfaces, with a
thorough discussion of prisms and prism-systems. .After
chapters on the reflexion and refraction of paraxial rays at
spherical surfaces, comes a full account of Abbe's theory of
Optical Imagery, by means of which it is possible to separate
theoretical from mechanical impossibilities. The theory of
Spherical .Aberrations and Colour-phenomena also receive full
treatment. A pleasing feature of the book is the fulness with
which the history of Optics is treated. The author's affection
for his subject is evident, and amid large arrays of determinants
and pages of symbols the human element is never lost sight of.
I'ull references to original sources are given, and in particular
the author acknowledges his indebtedness to Czapski's great
work. The book forms an excellent general introduction to
the speci.al theory of optical instruments, and another book
dealing fully with the different types of instruments may
possibly follow in time.

Tlic Yoiin^ Electrician. — H\- Hammo.nd Hall. 306 pages.
93 illustrations. S-in. X4-in.

(Methuen & Co. Price 5 -.)

A thoroughly practical book and one from which, if a boy
conscientioush- worked (with a little sympathetic assistance)
the series of experiments so subtly set forth in the succeeding
pages, he would gain an excellent knowledge of the fascinating
subject of electricity. Quite unlike the majority of " young '"
books it is practically written and yet is understandable by
the uninitiated ; and the final chapter, which deals with Wire-
less Telegraphy, leaves one like Oliver Twist.

One would suggest, just for boys' books, that the necessaries
for the experiments and the construction of the models be
tabulated, and the illustrations and diagrams should also be on
the opposite page.

PHYSIOLOGY.

The Physioloiiy and Hygiene of Sleep. — By Davih Fraslr
Harris. M.D., CM.. F.R.S.E. 19 pages. 7-in. X 5-in.

(Cornish Bros. Price 3d.)

The .Annual Public Lectures on " The Laws of Health " of
the .Midland Institute, Birmingham, are always interesting and
instructive, and this year's lecture, delivered in September.
1910. and here reproduced in the form of a small booklet is
certainly one of the best. Dr. Eraser Harris divides the causes
that normally lead to and produce sleep into four classes : —
The action of fatigue toxins from muscular and mental work ;
the diminution of the cerebral blood flow ; the regular recurrence
or, better, absence of sensations from the external world ; and
lastly the purely psychic causes, the absence of ideas, worries,
emotions and the like. He gives us numerous examples of
each of these types of sleep and shows how the opposite
conditions may give rise to insomnia. Particularly would we
agree with him, when he points out the general inconvenience
that results from the action of those w-ho go about our streets
late at night, singing and shouting, and asks for legislation to
stop this practice. Lastly, working along these same lines,
some simple but excellent advice is given for the recall of
" Sleep. O gentle Sleep. Nature's soft nurse I " by those who
have lost her companionship. The booklet contains one of
the best descriptions in popular language of the Physiology of
Sleep that we have yet seen.

ZOOLOGY.

Tlie Buul; of the .Animal Kingdom. — By W. Percival
\Vestell. 379 pages. 274 illustrations. 7-in. X9-in.

(J. M. Dent cS: Co. Price 10/6 net.)

Mammals are not classified in this book on any systematic
plan, for it is not intended to be a scientific treatise, but, as
the writer hopes, will appeal not only to young folks in the
homeland and in other places where English is spoken, but
also to adults who have a general interest in the subject. The
creatures, therefore, are grouped together according to their
exceptional size, their means of protection, and their ways of
obtaining their prey. The large number of photographic
illustrations, by Mr. W. S. Berridge, adds greatly to the
attractiveness of the book, and Mr. Westell has gone to some
of the best authorities for information that is not within his
own experience. V\'e learn that if this book has the reception
that it deserves it will be followed by another dealing
with birds.

XOTirE.S.

THE SCIENTIST'S REFERENCE BOOK AND
D I .A RV. — The present form of this useful annual consists of
two books joined together but opening different ways. The first
of these contains a diary with useful hints with regard to First
Aid. and a Daily Wants dictionary, which gives much valuable
information that is often required at a moment's notice. The
other book consists of tables and various facts, under the
headings of the different sciences, which are likely to be wanted

by scientific people. A certain number of leaves are also left
blank for memoranda.

Messrs. James Woolley, Sons and Company are to be
congratulated on the publication. Some of the information
with regard to the Scientific Societies is not quite up to date :
for the Royal -Anthropological Institute, the Zoological Society,
and the Selborne Society, among others, ha\ c changed their
addresses recently.

THE FACE OF THE SKY FOR JANU-RY.

r.v \V. SH.VCKLETON, F.K.A.S., A.R.C.S.

The Su.\. — On the 1st the Sun rises at 8.S and sets at
3.59; on the 31st he rises at 7.43 and sets at 4.44. The
Earth is nearest the Sun on the 3rd, when the Sun attains his
maximum apparent diameter of iZ' 35". Sunspots and faculae
may usually be observed on the solar disc ; of late the spots
have been small. The positions of the Sun's axis, centre
of the disc, and heliographic longitude of the centre are
given below : —

Date.

Axis inclined
from N. point.

Centre of Disc

S. of
Sun's Equator.

Heliographic

Longitude of

Centre of Disc.

Jan. I ...

2° i6'K

3° 7'

294' 30'

., 6 ..

o° iTW

3° 4i'

22S" 39'

,, II ...

2° 36'W

4° 13'

162" 49'

,, 21 ...

7° iS'W

5" 1 1 '

31° ^'

.. 31 ...

11° 40' W

6'' r

259° 2S'

Feb. 5 ...

■ 3° 4i'\V

6" 20'

■93° 38'

,, ID ..

15" 3b' W

6° 3^^'

127 48'

The Moon :-

Date.

I'hases.

H. M.

Jan. 8 ...
„ 14 ...

,, 22 ...
„ 30 ■■■

Fell. 6 ..

]) First Quarter .

0 Full Moon

•i Last Quarter ...

# New Moon

1) P'irst Quarter ...

6 20 a. 111.
10 20 |). 111.
6 21 a.m.
9 45 a.m.
3 28 p. 111.

Jan. 13 ...
,, 24 ...

Perigee

Apogee

0 18 a.m.
7 42 p m.

OccuLT.\TIONS. — The following are the principal occuUa-
tions visible before midnight : —

Date.

Star's

Name

So

Disappearance.

Reappearance.

Mean

Angle
from N.

Mean

Angle
from N.

rrH

Time.

point.

1 inie.

point.
E.

Jan. 1 1

[>' Tauri

4-2

l>.tn.

6. II , 79-

p.m.
7-17

237°

1 1

IP- Tauri

5'4

6-43 62

7.52

255"

■ • 12

125 lauri

51

10.21 107°

11.27

241"

Fell. 7

A' Tauri

4'5

5 26 8

6.4

304°

Mercury :-

THE PLANETS.

Date.

Right Ascension.

Declination.

Ian. I ...
■„ 16 ...

Feb. 15 ".'.

li. 111.

19 53

18 52

19 6

20 23

S 20" 36-
19° 31'
21' 23'

.S 20° 27'

Mercury is in Inferior Conjunction with the Sun on the
10th January and is thus nnobser\able for the greater part of
the month. Towards the end of the month the planet is a

morning star in Sagittarius, and rises on the 3, '. at 6.28 a.m.
or 1'' 16'" before the Sun. The planet is at greatest westerly
elongation of 25" 17' on February 2nd.

Venus: —

Date.

Right Ascension.

Declination.

Jan. 1 ...

, , to

„ 31 .
Feb. IS ..

h. m.
10 21

20 41

21 56
23 7

S 23" If

, '9" 45'
14" 12'

S 7 13'

Venus is an evening star in Capricorn, but practically
unobservable throughout the month. On the Jlst January
the planet sets at 6.8 p.m. or l" 21™ after the Sun.

M.\RS : —

D.ite.

Right .A.scension.

Declination.

Jan. I ...
.. 16 ...

•• 3'
Feb. 15 . -

h. ni.
10 27
'7 '2

17 59

18 46

■S 2r' 43'
23° 10'
2> 49'

.S 23-- 35'

Mars rises about 5.30 a.m. throughout the month, and is
\isible in the S.E. portion of the sky for a short time before
sunrise. The diameter of the planet's disc is only 4" ; thus,
under present conditions, useful telescopic observations are
practically impossible.

JUPITER :-

-

Date.

Right Ascension.

Declination.

Jan. I ...

.. 21 ...

Feb. 10 .

h. m.
14 30
14 41
.4 4S

•S 13° 37'

14" 24'

S 14" 52'

Jupiter is a conspicuous object in the morning sky looking
S.E. ; he rises about 3 a.m. on the 1st January and at 1.20
a.m. on the 31st.

He is in quadrature on the 3rd February. The equatorial
diameter of the planet is 34", whilst the polar diameter is 2"'2
smaller. This polar flattening is readily observed in telescopes
powerful enough to see the belts, but the satellites may be
seen in small telescopes such as deer-stalkers of about
It inches aperture, or even in a good pair of prismatic
binoculars magnifying 8 times. The Moon appears near the
planet on the 23rd.

Saturn : —

Date.

Right Ascension.

Declination.

Jan. I ..

., 21 ..

Feb. 10 .

!i. 111.

' 54
1 55
1 59

N g-' 0'

9" 12'

N 9" 40'

Saturn is due South on the 1st January .'it 7.13 p.m. and at
5.18 p.m. on the 31st. The planet appears as a bright star

37

38

KNOWLEDGE.

Janl',\ry, 1911.

looking South and about 30" abo\e the horizon ; he is very
con\enientIy situated for making ielescopic observation, and
with his rings he forms one of the finest sights in the sky.

The ring may be seen quite well in telescopes of about
\i inches aperture with a magnifying power of 40, if the
instrument is sufficiently steady and the object glass good ;
but larger telescopes are required to see the division in the
ring and the belts on .the disc. The planet is in quadrature
on the 21st, and sets at 11.24 p.m. on the 31st.

As seen in the telescope the ring appears fairly open, since
we are looking on the Southern surface at an angle of 16°.
The apparent diameters of the outer major and minor axes of
the ring are respectively 42" and 1 2". whilst the diameter of
the ball is 17".

The Moon appears near the pLiiut lui tin- Stii.
Ur.wi'S : —

Date.

Right Ascension.

Ueciinatiun.

Jan. I ...
Feb. I ...

b. 111. s.
iq 45 4.S
19 53 ^o

,S 2I'-' 43' 46"
S 21'' 24' 3"

Uranus is in conjunction with the Sun on the 16th January ;
hence the planet will be unobservabk- throughout January and
February.

Neptune : —

Date.

Kight Ascension.

Declination.

Jan. I ...
Feb. I ...

h. 111. s.
7 2S 6
7 24 28

N 21° 15' 5"
N 21° 23' i"

Neptune is in opposition to the Sun on the 11th. hence
about this date he is on the meridian at midnight. The planet
is situated in Gemini, about three and a half degrees South-
East of the star 5 Geminorum. but he is difficult to identify

except in large telescopes. He may, however, be detected by
his relative motion if successive observations are made at
intervals of some days.

Meteor Showers: —

Date.

Radiant.

Name.

R.A.

Dec.

Jan. 2 ;
.. 17

b. 111.

XV. 20 +53=
XIX. 40 +53

i

Quadrantid.s.
0 Cygnids.

Miniiua of Algol occur on the 4th at 11.35 p.m., 7th at 8.24
p.m., 10th at 5.13 p.m., 27th at 10.7 p.m., and the 30th at 6.56
p.m. The period is 2"" 20*^ 49°" from which data other minima
may be calculated.

Telescopic Objects: —

Nebul.^e. — Orion Nebula, situated in the sword of Orion,
and surrounding the multiple star 9. is the finest of all nebulae;
with a three or four inch telescope it is best observed when
low powers are employed.

Crab Nebula (M D. in Taurus, situated about IV North-
west of .f Tauri, in K.A. 5^ 29", Dec. 21° 58' N.

Cluster. — M 37. situated in Auriga, is one of the finest
clusters, and verv compact ; its position is R.A. 5'' 46",
Dec. il" 32' N.

Double Stars. — /i Orionis IRigell. mags. 1 and 9, separa-
tion y". On account of the brightness of the principal star,
this double is a fair test for a good object-glass of about three-
inch aperture.

S Orionis, mags. 2 and 7, separation 53 " ; easy double.

.t Orionis, triple, mags. 3. 6, and 10, separation 2"'5and56";
rather difficult in a three-inch telescope.

X Orionis, mags. 4 and 6, separation 4"' 3 : pretty double.

<r C)rionis, triple, mags. 4, 8, and 7, separation 12"'5 and 42".

NOTICE.S.

YEAR BOOKS. — From Messrs. Adam and Charles Black
we have received "Who's Who" for 1911 (price 10 - net).
Apart from being indispensable to everyone who is doing any
public or commercial work. "Who's Who" contains many
facts of considerable interest and not a little humour, as those
will find who take the trouble to dip into its concise biographies.
From the same publishers comes the "Englishwoman's Year
Book " (price 2 6 net), which this year has been divided into two
parts, the first dealing with education, professions and social life,
and the second with philanthropic work more particularly.

The " Writers' and Artists' Year Book" (price 1 - iietl. is
chiefly of value to literary people and should be of particular
use to those who are thinking of getting a living by their pen.

■■ The Year Book of Scientific and Learned Societies,"
published by Messrs. Charles Griffin & Company (price 7 6),
has for more than a quarter of a century given the more
important details with regard to all the scientific and learned
societies in this country, and set forth the titles of every paper
and lecture read or delivered before theiu during the year with
the name of the author. The issue for 1910 is in every way
equal to its predecessors and it is obvious that few scientific
workers fail can to get some information or inspiration from
a study of its contents.

.•\mong other Year Books which we have received are
"Whitaker's Almanack" (price 1/-; in cloth 2/6 net. I, and
"Whitaker's Peerage" (price 5/- net.), which present certain
new features but which are more particularly useful on account
of the old ones.

SCIENTIFIC INSTRUMENTS.— We have received from
the Cambridge Scientific Instrument Company, two illustrated
leaflets. The first deals with a large sliding microtome which
is important from a scientific point of view as with it very
large sections can be ctit from material embedded in celloidin.
In point of fact the maximum size is 150'"" by 120""", that is, the
largest section will measure 6 X4i inches; and in illustration of
the capabilities of the instrument a figure is given of a
complete section of a human leg six inches above the ankle,
which was prepared and cut by the new microtome at the
.\natomy School at Cambridge University.

The other piece of apparatus is an automatic temperature
regulator which is specially valuable in its application to
industries. In jam factories, for instance, the girls often badh'
scald their hands owing to the water used for washing jars
becoming too hot. To take another case, the hot potash used
by electro-platers can be kept at the most efficient teiuperature
and prevented from boiling over. The thermostat, which
does the regulating, is dependent upon the fact that a tube of
brass expands with heat while a rod of nickel steel within
does not appreciably change its length.

APPOINTMENT. — We are pleased to notice that Messrs.
E. Dent and Company, Limited, of 61, Strand, and 4, Royal
Exchange, have received a royal warrant, appointing them
watch, clock, and chronometer makers to His Majesty King
George the Fifth.

QUERIES AND ANSWERS.

Readers arc invited to send in Questions ami to ansicer the Onenes icItieJi are printed fu tliis page.

QUESTIONS.

Numbers 14. 16. 17. 18. and 20 (Page 461) still remain
nnanswered-

21. ASTRONOMY .WD GKOGK.APHY.— Will any fellow-
teacher advise me as to good school experimental and observa-
tional courses in astronomj- and geography ?

Bei.i.krbv Lowkrison.

22. K.ADIUM. — Seeing that Radium is not a stable
substance, but is continually changing with other forms of
matter, none of which are stable as far as we know, how is
it that Radium is still found in the crust of the earth ':

J. G. Sparke (Lieut. -Ciilonel).

23. THE GULF STRE.\M.— .\ friend mentioned the Gulf
Stream the other day, and I remarked that I understood that
this was now considered to have no effect whatever on Britain.
Will you briefly inform me. in "Knowledge." if I am correct,
and what are the facts of the case ; how far away is the nearest
trace of this stream perceptible, and so on r

S. P. Rowlands.

24. DRIi.-\MS. — I should be pleased if some of your readers
would give an explanation of the following common occurrence
in dreams. Suppose one dreams of an impending railway
collision. In the ordinary sequence of events, one dreams of
the two trains approaching one another before the actual
collision. Now it is a peculiar fact the collision is frequently
emphasised in the world of reality b>- a door banging, or some
such sudden noise. In fact, one might almost say that every
real occurrence impressed on our senses during sleep fits in
perfectly with the whole plan of the dream. In the example
I have just cited one expects a noise at the moment of the
collision, and it happens. If that particular door was not
about to slam it is probable, in fact almost certain, that that
dream would not ha\e occurred.

Do you think this any evidence that the mind is often
aware of the e\ents of the future : , P ...

TIDES. — There is a point in connection with the tides of
the ocean which I have never seen elucidated in any popular
manner.

Tidal friction causes retardation in the rotation of the earth.
and by the principle of conservation of the moment of
momentum the revolution of the moon is accelerated. This
is the basis of Darwin's theories of tidal evolution, and, of
course, remains true whatever may be the lag of the tides
behind the moon. The acceleration of the moon is sometimes
further explained by a diagram illustrating that the nearer
tidal protuberance exerts greater attraction on the moon than
the one opposite, much as the precession of the equinoxes is
always illustrated. Now the depth of our oceans being less
than the critical depth of about fourteen miles, our tides are
inverted, that is, high tide where low tide would be expected,
and vice-versa : but if the depth were greater than fourteen
miles the tides would be direct, and the nearer tidal protu-
berance should be behind instead of in front of the moon, and
it seems to need popular explanation why a retardation of the
lunar revolution does not result. The whole question of the
lag of the tides on an ocean-covered earth might receive more
notice in popular accounts, though probably too mathematical

for full elucidation. i n ^

J. H. (i.

REPLIES.

10. W.\TER .-^ND ITS OWN LEVEL.— I am a little
perplexed myself about what G. G. B. has mentioned about
water and its own level.

It is. I believe, one of the strongest arguments uf flat
earthists, and the flat earth idea is certainly wrong, so there
must be some explanation that will answer his query.

Is it that, taking for example a square mile of ocean, it is

such a small area that the water certainly finds its own level

within that radius, but taking the oceans themselves they must

take the curvature of the earth, so in the one sense does the

water find its own level, while in the wider sense we must also

forget that the earth has a great power of attraction, and so

the gravitation of the earth makes the oceans take the shape of

the globe. . , ,

" A. Mercer.

11. .\ BOOK ( )N W.\SPS.— In .answer to Mr. Sandeman's
enquiry for a book on wasps, I venture to recommend " Wild
Bees: Wasps and .Ynts and other Stinging Insects," by
Edward Saunders, F. R.S. It is a popular work of about
one hundred and fifty pages, with four coloured plates, and
other illustrations, published two years ago by Routledge.
The price. I think, is 3s. 6d. \f A c;

13. THE FINDING OF THE TIME .\T XKiHT.— The
time may be found at night approximately by means of the
accompanying adjustable dial ; this may be used either by
direct comparison, or studied until it can be retained in the
memory suflftciently for comparison with observation.

1 Polaris

md i Ursae minoris.

1 Jan. 1 July
1 Feb. 1 .\ug.
1 Mar. 1 Sept.

VIII 1 1 .\pr. 1 Oct.
VI 1 Mav 1 Nov.
IIII 1 1 Jun. 1 Dec.

II

XII

X

FiGlRE 1. The Dial.

39

40

KNOWLEDGE.

jANl-AKV, 1911.

The moveable circle i.s adjusted in accordance with the
little table. The number given for the 1st of the month is
brought opposite the pointer, which represents the top of the
imaginary celestial dial at the Pole. The circle is then moved
on. counter clockwise, through the fraction of the ne.xt two-
hour interval w'hich corresponds to the fraction of the month
elapsed.

In direct comparison the dial is held up with its back
towards the Pole, with the pointer at the top. The line joining
Polaris and 13 Ursae Minoris is compared with it ; and an
imaginary line is drawn across the centre of the dial parallel
to that line. This imaginary line shows the time according to
the hours marked on the dial.''

If it is desired to study the method so as to be able to work
without the dial, the student may keep the dial by him.
adjusting it every few days. He should study the dial, the
adjustment of which changes slowly, and remember it. so as
to be able to work without it at night i using it, if necessary,
for verification. The changes run through a year, sometimes
the one star and sometimes the other being uppermost. After
a year's practice the changes should be sufficiently engrax ed
on the memory to admit of finding the time roughly without
the direct use of the dial. But the scheme is a little
complicated ; and it will be con\enient to have the dial at
hand to refresh the memory.

The principle is not difficult. .\11 star phenomena occur
about four minutes earlier for every day that passes. This
arises from there being one more sidereal day in the year than
the nmnber of solar days. The resulting change of twenty-
four hours is distributed o\er the year in a maimer strictly
proportional to mean time. Thus, if the months were of
exactly equal length, the change in each month would be
exactly two hours. As it is, a small irregularity arises from
the varying lengths of the months, which may be neglected
for our purpose.

It is desirable to take stars always visible. We take the
Pole-star and /i Ursae Minoris. The latter is the nearer to
the Pole of the two conspicuous stars ji and y Ursae Minoris,
which lie near together at distances of about sixteen degrees
and eighteen degrees from the Pole' respectively.

The times indicated by the line joining any two stars near
the Pole can be determined by a single accurate observation.
This observation should be made when the line is either
\ertical or horizontal, or preferably, obserxation should be
made in both positions. In other positions the observation is
much less certain. In the present case the observations were
made a day or two before and after 1st December. 1910. when
the vertical position occurred at ten o'clock, and the horizontal
at four. This determines the table of adjustments.

In estimating angles it is sometimes of use to note that the
stars -i and 7 Ursae Minoris subtend just half an hour at the
Pole ; and we may take it that the angle at Polaris is sensibly
the same.

In one of Hardy's novels (I think " Far from the Madding
Crowd") the shepherd is said to be able to tell the time from
the stars. I have often speculated whether this is possible for
an uneducated man. It appears to be possible, though
improbable, given the outdoor habit at night, a clear head.
and either a good memor}', or a habit of making notes.

.Any observant person much out at night must notice that
the star phenomena change their times, being earlier every
night. Also he might notice that they recur after a year.
The deduction of the two hours change per month seems to
present the greatest difficulty from this point of view, though
it is quite simple when explained. Then, one good observation
only is required to determine the time by any line joining two
stars near the Pole. But it would want a clear head to keep
the changing scheme of the hours always in view.

The same moveable disc would do for any pair of stars
near the Pole, the setting table only being determined by
observation.

This method is not susceptible of considerable accuracy.
It is a recognised principle in naked eye astronomy that the
roughest measurement is better than the best eye estini.ate.
Here there also appears to come into play, for positions
intermediate between the vertical and horizontal, one of those
illusions which depend on the structure of the eye. I myself
see the bisector according to time between the horizontal and
xertical positions decidedly nearer the vertical than the
horizontal. This is in the sky, not in the dial, which subtends
a comparativeh- small angle at the eye. The resulting error
may be either fast or slow, according to the position. I
believe it depends on the fact that, in a figure subtending a
considerable angle at the eye, the eye estimates vertical
distances on a larger scale than horizontal ones. This may
arise from the retina being slightly flatter vertically than
horizontally. If one is able to estimate the amount of this
error for one's ow-n eye. one may allow for it roughly. The
vertical and horizontal positions admit of fairly accurate
observation. ^ R H \[ H

ECLIPSES. — The two following questions have not been
numbered, as they are here answered.

Does a total eclipse of the sun occur, on an average, ten
times in one hundred years — of course, astronomically ?

A total eclipse of the sun may occur on the earth more than
once in a year. From the year 1851 forty total eclipses have
occurred, but may have not been observed (astronomically)
owing to inaccessibility (near the polesi, to being only visible
at sea. or to cloud interference. Total eclipses of the sun
occur in cycles, the path of total phase gradually moving
southward or northward over the earth's surface and taking
over one hundred years to return to a similar point ; and a
cycle of about fifty-four years, which may be divided into
three periods of eighteen years, the area of total phase
moving east to west ; so that every fifty-four years the
eclipse is at the same longitude, though gradually moving
to greater or less latitude, according to the other cycle
movement.

Was a total eclipse of the sun visible at Greenwich in the
year 1900?

No total phase was visible at Greenwich in 1900: no total
eclipse had been visible in Great Britain for about one
hundred-and-fifty years : there will be a momentary one about
1927, and again in 1999. and possibly for a second or so in
one or two other vears this century.

NOTICES.

X-K.AVS. — The Sanitas Electrical Company, of 61 New-
Cavendish Street, W., have sent us a booklet containing a
large number of testimonials from workers in X-rays and
electro-therapeutics, as well as physicists, upon the results
obtained with their apparatus, including " Sanax " X-ray
Outfits, Intensified Induction Coils, and the Motor Mercury
Interrupter ; as well as their " Multostat" Universal Apparatus.
In addition to illustrations of the apparatus, reproductions of
two remarkably fine radiographs are gi\'en.

EXPOSURE RECORD.— "The Wellcome Photographic
Exposure Record and Diary for 1911 " has also reached us.
It contains a great many hints for the benefit of photographers,
in addition to a neatly arranged series of tables in which
the owner may record all the details with regard to his
exposures. There is, besides a diary, an exposure calculator
and Several interesting illustrations, including the reproduction
of a colour photograph developed with tabloid photographic
chemicals. The price is one shilling.

Note. — The motion round the Pole looking N. appears counter clockwise. Looking S. the motions seen appear clockwise.

Knowledge.

With which is incorporated Kard\vicl;c's Science Gossip, and the Illustrated Scientific Nc's.

A Monthly Record of Science.

Conducted by Wilfred Mark Webb, F.L.S., and E. S. Grew, M,A.

FEBRUARY, 1911.

APPARATUS FOR PHOTOGRAPHING NATURAL

HISTORY OBJECTS,

Bv \\". FOTHERIXCHAM.

Collect, e.xamine and record, is probabh- a good
sumniar\' of the work of the average Nature student.
He has not gone far in his work when he innds that
to properly examine all he collects lie requires a
microscope, and that to record his finds in the easiest
and most truthful \\ay, he must
have a camera. Now the enthusiast
will soon find himself in difficulties
about apparatus, especially apparatus
for recording his facts, either for
future comparison or for the benefit
of others. \\'hat ought to be a
pleasure, the making of an interest-
ing, perhaps [)rett\', picture of his
facts, is, owing to tault\- apparatus,
a disagreeable task, costly in time
and uncertain in results. So for
ever\- ten who are skilled in the
first two parts of the work there
is probabh- not one in the third.
To carry out this programme let
us see what is needed. Supposing
the collecting and examining be
"taken as read." he requires: —

(1) A Field Camera. If this is of the -hand
or stand" type, it will "cover a multitude" of
things.

With it he inav. with some circumlocution,
even take at home, with pains, indifferently good

Figlike 1. '
The Camera used for enlarging or reducing.

With improvised condenser and jet on optical bench. Also a snpplementary board, on which olijects ma>- be
pinned out when the apparatus is used as ordinary or copying camera.

.^ 15x12 Photoinicrographic Camera.

With woihIcii optical bench, Watson "Van Heurck" microscope, Nelson Condenser, and acetylene jet on
sliding wooden feel, permitting right angle centring adjustments.

pictures of " birds, beasts and
reptiles."

Ultimately he will probab]\ get
a bigger camer:i on legs, that beha\-e
themselves better on a floor th;ui do
those of the ordinary field tripod.

Even then he will be annoyed
to find that he cannot take a picture
of many things, in spite of much
}.)inning-out and arranging on board
or wall, and that such things as
eggs have an ugly shadow round
them, while fragile dissections are
out of the question, as is an\- pre-
paration floating in fluid. He will
probably long for a vertical arrange-
ment that will enable objects to be

41

42

KNOWLEDGE.

February. 1911.

laid beneath the camera, and
illuminated either by transmitted

(2) To get photographs of
minute objects through the
microscope, he probabh" has tht-
usual horizontal photomicro-
graphic camera, and nothing
can be better for mounted
objects : but the biologist, as
distinct from the photographer,
wants to preserve the record ot
objects as they appear when
fresh, and not formalined or
dehydrated and beautifulK
" squasjied " on neat slides.

So here also he wants a
vertical apparatus to take such
objects as cannot be pinned up.

(3) To complete his wcirk lie
probably also has an enlarger,
and an arrangement for making
lantern slides.

Now, with a full know ledge of
practically all that is offered by
both English and Continental
makers. I am \-et of opinion that
there is no handv apparatus that
will do all this, and that the
various equipments now on the
market, although vastly iiu-
proved within the past five
years, are still unsatisfactory.
Most of them are too small
and incomplete, being without
stability, adaptability, and
rigidit\", and without optical
bench, which means sans every-
thing that is essential.

\\'riting some time ago to
the maker of a new photomicro-
graphic camera. I pointed out
that this camera failed to meet
mv needs and gave details of
objects I wanted to photograph.
He replied : " We prefer to use
separate apparatus for such
work."

E.xactly ! So have I in days
past; and the result has been:
two ordinary cameras, two
photomicrographic cameras, a
bulk\- enlarging and reducing
camera, and a host of fakes and
fitments in the shape of easels,
backgrounds, glass platforms,
and so on — a lot of dusty,
unready apparatus that lumbers
one's working space and would
require one's whole time to keep
in order.

How often after a clean up
have I said: " I wish the\- could

}et be properly
or incident light.

all be rolled into one " and one day— happ)' thought !

— I said. " I w ill roll them all into one," and almost
literally did so.

The result is a camera,
suited for practically every need
of the biologist, more easy of
manipulation, and withal a lot

cheaper than anything I can

find

Figure J.
Camera raised to "vertical position on hinges.

Il is secured by two T bolts with B.tusch and Eumb " V "
dissecting microscope, Nelson condenser and jet.

With sliding glass platform on
optical bench support with l.irge sheet of ground glass,
prevents reflections from the water.-

elsewhere.

Being composed mostly of
parts of other apparatus, as I am
no tradesman, it may appear a
bulky collection of odds and
ends, but it is at least as compact
as anv other one photomicro-
grai)hic camera, and more useful
than an\- other two, covering
with great ease an enormous
range of work.

The idea, however roughly
carried out. is sound, for both
English and Continental makers
have been groping their way to
this type for some years.

Unquestionably this type is
the apparatus of the future in
all but the largest laboratories,
where space and expense do not
retiuire consideration.

In Eigure 1, it is shown as
the usual horizontal photo-
micrographic camera, having
four feet of bellows extension,
capable of the highest power
wiirk.

Without the microscope, but
with a sliding easel in the
wooden runners (an improvised
iiptical bench), it makes a
splendid 15X12 copying caiuera.

In Figure 4. it is shown as a
vertical photomicrographic
camera. .\n ordinary dissecting
microscope stand, with a wide
tube fitted to the arm, will be
found to make an excellent
substitute for the costly big
microscope, especialh' w hen large
wet objects are being dealt
with. .\ Dunning's live cell is
a very useful adjunct for such
work, and a mess of water
round the stage w ill do the stand
no harm.

Figure 3, shows the camera
as a purely vertical camera,
plus a sliding glass platform
on the same upright as the
camera, upon which even such
contrary things as eggs may be
laid, a morsel of " Plasticine " on
the underside preventing rolling.

Febrtary. 1911.

KNOWLEDGE.

43

Or a glass tank ma)- be set on the transparent
platform, and here the apparatus is invaluable —
difficult and fragile objects may be displayed in
water, any suitable background can be put in below,
or various tints easilv tried, without disturbing the
object.

Further, a fish or other object can be hardened in
formalin in a lifelike attitude, or simply spread out in
water. A background of weeds, sand, shells, and so
on, can be arranged on an opal glass below, the object
being raised up or down from the background on
the sliding platform, till the correct effect and the
absence of shadows has been obtained, and the
subject photographed in apparenth" natural surround-
ings, with striking results.

To prevent reflections from water and wet
preparations, a ground glass screen can easily be
adjusted on the optical bench, as shown, or coloured
glass to get orthochromatic effects without screens
in front of the lens.

If need be, a condenser can be made to play
a beam of light on the object, with no more

trouble than adjusting it on the optical bench.

Figure 2 shows the apparatus being used as an
enlarging and reducing camera, which can be used
with or without artificial light.

The essential features of this apparatus are : —

1. A camera, sliding easily in i central groove,
and giving about four feet of extension, with suitable
fittings, as indicated.

2. An optical bench, with fittings, '_■ -:si;'ng of
sliding platform for microscope, condenser, .' nd
troughs or screens, also sliding fittings c.
taking a glass or board easel; all being ceinieu lh
the bench.

This last is vital : to have all parts in alignment
and centring adjustments to keep them so, is the
secret of success. A camera of this t}'pe without an
optical bench as a permanent fixture is only half
finished, and will infallibly lead to waste of both
time and plates.

In m}' opinion such a camera complete need not
cost more than ten pounds, and could be made so as
to secure some measure of portabilitv.

JAMES WILLIAM TUTT, F H.S.

On January 10th, there passed away the well-known ento-
mologist, Mr. Jas. William Tutt, who for the past twenty years
has been the editor oithe Eiifoinologist's Record and Journal
of Variation, and who, for many years, has been a regular
attendant at, and participant in the work of several of our
London Societies. He was a native of Strood, Kent, where
he became a pupil-teacher, and from whence he passed to
St. Mark's College for Schoolmasters. He entered the service
of the London School Board, and having been promoted time
after time, was last year selected to open one of the first of the
new Central Higher Grade Schools, which are now being
established by the London Education Authority. The study
of insects was his hobby, and in spite of the onerous burden
of his educational duties, his ability, capacity for work, and
his forceful character, brought his writings many an eulogistic
recognition, not only from all parts of the United Kingdom, but
from many Continental circles ,as well as from America. At
the time of his death he was President-elect of the great
Entomological Society of London. For some years past he
had been the editor of the annual organ of the South-Eastern
Union of Scientific Societies. His earlier writings were more
of a popular nature than his later work, and we may mention
those admirable descriptions of country rambles, " Random
Recollections of Woodland, Fen and Hill," and " Woodside,
Burnside, Hillside, and Marsh." For the past fifteen years
Mr. Tutt had spent his holidays in the Alps, and his enthusiastic

nature pictures in " Rambles in Alpine Valleys," and in many
articles written by him in the Record, have led numbers of
our insular workers, including the present writer, to extend
their narrow experiences and views, by investigating the insect
fauna of numerous beautiful regions outside the routes of
the ordinary superficial tourist. " The British Noctuae and
their Varieties " was a book giving an intimation of the more
serious work of which Mr. Tutt was capable. This was
succeeded by " The Migration and Dispersal of Insects,"
" The Natural History of British Butterflies," and soon, works
requiring much research and leading up to the commencement
of a huge encyclopaedic work, which was of so ambitious a
nature that one individual could only have imagined himself,
even with long life permitted him, able to write but a small
instalment. This was the " Natural History of British
Lepidoptera " of which he issued eight volumes, and was at
the time of his death engaged upon two more. Mr. Tutt had
attracted around him an enthusiastic band of co-workers,
Continental as well as British, and the original work done by
these gentlemen, his own work and criticism, with a huge
amount of all the best done in the past, he welded together
with a master hand and had illustrated by the best men,
acting under his skilful advice and supervision. The study
of F"ntomology, by his death, has lost a huge force, and it
will br long ere another can step in to fill his place.

Henry Turner.

THE SUN SPOT (GROUPS OF 1906.

A SPECIAL interest attached to the Sun Spot groups of 1906,
because in that year sun spot activity or prevalence was
hypothetically at the end of the thirty-five year cycle which
has been assigned to it, and should have reached its last
maximum. Activity on the solar surface was much less in the
early part of that year than in the corresponding period of the
previous year. The last phase of the maximum spot period
seems to have begun in the earlier half of 1906. A com-
parative calm prevailed till May 12th, when a great outburst
of solar activity occurred. .At the end of July two large spots
appeared, both of which became \isible to the naked eye
during .August. The larger of the two spots developed a great
deal during its passage across the Sun's disc. When first seen
on July 2Sth it appeared as quite a small spot and in the
course of its transit had grown to ten degrees in length and
six degrees in breadth. A period of calm followed, which was

broken by a stream of spots lasting through November till the
middle of December. In the next year, the maximum
appeared to have been passed.

Dr. C. L. Poor, as the result of his discussion on the figure
of the Sun, derived partly from a study of the solar photographs
of the Rutherford series extending over several years, and also
from the heliometer measures made by the German Transit of
Venus Expeditions, concluded that the ratio of the polar to the
equatorial diameter of the Sun was a variable quantity, and
had relation to the presence or absence of solar spots. This
is a conclusion which has since been disputed, but is one of the
more interesting speculations with regard to the periodicity of
sun-spot areas. Schur and Ambronn did not support Dr. Poor's
inferences ; and Dr. C. G. Abbott's recently published memoirs
on the Sun, while favouring variations of solar radiation and
brightness, does not relate them to variation in the Sun's figure.

From a Jthoiogrnfih taken a!

Sun Spot Group, August. 1906. 3d. 17h. 10m. Greenwich Civil Time. Enlarged two di.-imeters.

Diameter of Sun's image 5 feet.

I Sec pai^c i.!).

44

SIR FRANCIS GALTON, D.Sc., F.R.S.

Sir Francis Galtox, D.Sc. F.R.S. . who closed
a long life of many and useful activities on Tuesda\",
fanuary 17th, after a very brief illness, was born on
Februar\- 16th. 1822. He came of a long-lived
familv. a fact on whicli it does not seem superfluous
to dwell, seeing how great a stress Sir Francis Galton
laid on parentage and family in determining the
characteristics of the individual. To his kindred
and ancestrv he attributed not merely his physical
and mental attributes, but his predilections and his
length of years. A reference to his work on
" Noteworthy Families," which was compiled chiefl\'
bv reference to the Fellows of the Royal Societ\',
discloses that on one side he sprang from the Galtons
and the Barclays, and on the other from the
Darwins. Among the Barclays was that Captain
Barcla\- who astonished the earl\- Victorian world
bv walking a thousand miles in a thousand hours,
and it was to this strain that Sir Francis was
accustomed to refer his own unusual power of
enduring physical fatigue without harmful results.
His longevity he attributed to the Darwins, and
some of his mental powers must have been inherited
from the same fount : but his paternal grandfather
was a scientific man as well as a good man of
business, and the Barclays, apart from the peripatetic
Captain, were bankers. It was, however, to the
commingling of ancestors that he owed, as he obser\'ed
in his Reminiscences, a considerable taste for science,
for statistics, and for poetrv.

His education was not less composite than the
qualities which were bequeathed to him b\- his
progenitors. His mother would have had him
become a physician like his grandfather. Dr.
Erasmus Darwin. But he developed a mathe-
matical gift and, after a boyhood spent at two
French schools and one English grammar school, he
went up to Cambridge as a mathematical aspirant.
His fine health failed him there, however, and after a
severe illness he left the University with nothing
better than a pass degree. He used to say in after
vears that when he found himself one dav elected
to an Honorary Fellowship of Trinity College, he
was so surprised that he thought it \\'as a mistake.
After Cambridge he walked the London hospitals,
but here again he failed to find his vocation, and the
death of his father found him \\ ith his career in life
still undetermined. So, having private means, he
went, like many another in the same case, on his
travels. But his " wanderjahre " was prolonged.
It comprised the Soudan as far as Khartoum — in
the pre- Khalifa days — Syria and Palestine, all viewed
under conditions very different from those of to-da}".
But his travels were actually his first passport to the
world of scientific research, for in 1854 the Royal
Geographical Society- awarded him its medal for his
explorations of Damaraland and Xamaqualand.

But before that his marriage (in 1853) had settled
him in England : and he began to interest himself
specially in meteorology. He was associated with

that Roxal Obserwatory at Kew which is now a
landmark for golfers ; and among the important and
permanent measures which arose from the associa-
tion were the standardising of se.;iants and other
angular measuring instruments, the verification of
tliermometers. tli' Kew rating of watches. Under
Dr. Francis Gail:oii. the old Kew observatory
became the first English Reichsanstalt ; the primi-
tive ancestor of the National Ph\-sical Laboratories
at Bushey. He did lasting work in meteorology
\\hile at Kew, and the term "anti-cyclone" as
descriptive of a weather type which lately has over-
hung the larger part of Western Europe, was of his
coining. The counter-clockwise movement of winds
in cyclones had been appreciated and understood
before his time, but the movements of the comple-
mentary atmospheric systems had received hardl\-
any notice or explanation.

It is, however. Galton's work in heredity which
seems now to ha\'e been his most important contribu-
tion to science. Heredit\- had al\\a\s interested
him ; and his researches may be said to have been
based on Gauss's theorem. Gauss supposed all
variabilit\' to be due to different and equallv probable
combinations of a variet}- of causes. Galton desired
to test this theorem by the light of those character-
istics of human kind which are measurable. He
therefore set up. in 1884, an Anthropometric Labora-
tory, in which were measured the more obvious
characteristics, such as height, weight, span of arms,
and so on, as well as the less obvious ones of keen-
ness of sight, colour sense, lung capacity, reaction
time, personal equation in various aspects. B)'
examination of data thus derived he hoped to find
what influence parentage had on the physical attri-
butes of offspring — and for a generation he preached
the multiplication and usefulness of such labora-
tories. It was while examining the Bertillon system
of anthropometrx' that Galton developed another
measurement of idiosA'ucrasv — the finger print —
though in his Reminiscences he is careful to
sa\' that Sir William Herschel in India had
experimented with finger prints as a method of
identification since 1887 ; he gave priority of
method to Mr. Henry Faulds, who is still living. As
a necessar\- corollar\-. if indeed it may not be more
properly described as the fount and well-spring
of his work in anthropometry, arose his investigations
in that science of " Eugenics," to which he gave
its name ; and which is the science (of right breeding)
that aims at the discovery in man of those qualities
which are desirable for his survival and progression.
One may say in summation of his theoretic position,
that he was a disciple of Weissmann rather than
of Hering or of Butler : and that he was
tempted to reduce the conditions of inheritance to
a mathematical formula, as Pearson and the
geometricians seek to do, and to suppose that
each ancestor contributes a share to the in-
dividual proportional to the distances of relationship.

45

CORRESPONDENCE.

POLAR PHENOMENA.
To the Editors of " Knowledge."

Sirs, — "Anxious" asks a question with reference to the
period of slow motion of the Sun in the Arctic Regions.
Perhaps the followint; investigation may throw some light on
the problem.

Let QO' be the celesli;;! equator, and EE' the Ecliptic, the
angle w of inclination being 23° 2S' approximately. Let S'
represent the sun whe.; close to E', the Solstitial Point, and S
the sun when in the ...iier.

ElGUKE 1.

Let 5 be the declination at S', and S + l the declination at S,
where \ is very small. Let the arc S'S be x'- (For the
present we ignore the latitude of the place.) See Figure I.

Now, the problem is to find the value of the arc S'S, and
from this the number of days corresponding. Consider the
spherical triangle E'Q' T sin E'Q' = sin w sin TE', or (1) sin
(5+A) = sin u, since TE^ is 90°. Similarlv, from the spherical
triangle S'KT sin S'K = sin S'X sin w. Now S'K is 5 the
declination, and S'T is 90 — x

.'. sin 5 = sin (90 — xl sin w
or sin 5 = sin w cos x- (2)
Subtract (21 from (11. and we have
sin (5+A) —sin 5 = sin m (1 —cos x)
or sin 5 (cos A — l) + cos i sin A = sin w (1 — cos xl
Now A is very small, and 5 = w approximately
.'. cos A = l, and (cos -1 — 1) may be neglected

in the above equation,
.'. cos w sin A = sin w (1 —cos x)
or 1 — cos x = sin A cot w.
cos x = l~sin A cot w. (31
Now, let us suppose that A does not vary by more than one-
fifth the Sun's diameter, say 6'. Such a small variation in the
Sun's declination would practically give him the appearance of
being stationary. Substitute in (3), 6' for A

cos x = l— sin 6' cot 23" 28' = 1 -'001746 X
2-303 = '9959 .'. x = 5- 10'.
Hence S'S is an arc of 5° 10'. As the sun will attain the
same declination after passing through the Solstitial Point at
S" where SS" = SS^ = 5" lO', the actual arc traversed by the
Sun, while his declination changes by 6' is 10° 20'. Reckoning
approximately V per day for his motion in the Ecliptic, the
number of days during which the declination varies bv 6' is
about lOi.

Now, suppose we allow A to vary by lO', or about one-third
the Sun's diameter.

In this case cos x = l— sin 10' cot 23° 28'
= 1 -"002909 X2'303
= '9933005
.•. x = 6° 38', 2x=13° 16'

and time is about 1 3 days.

Let A varv bv 20' : then cos x = l-sin 20' cot 23° 28'
= 1 - '00582 X 2'303 = '986596
X = 9° 24' 2x= 18° 48'
and the time is about 19 days.

Let us now assume a latitude of 86 j say.

In Figure II Z is theZenith, P the pole. HR the horizon for
latitude 86A : the arc ZP is then 90°-86i° = 3i'='. At the
vernal eijuinox, the Sun, being in the equator, will describe the
arc QQ', but when the declination is iV\ he will not set. but
at midnight will just graze the horizon. After thi^ In- \\'\\\

2 P

Figure 2.

continue to rise each day higher above the horizon, and at the
Solstice his path during the 24 hours is the small circle GG'.
The time he appears to stand still is evidently the same for
any latitude, for the changes in declination are in no way
affected by the latitude of the place. Thus, though he does
not set when describing the small circle GG', his declination
is slowly changing at the rate of about 5 for lOJ days, or 20'
for 19 days. This causes his diurnal path to suffer very little
perceptible change during this period, and at a latitude where
he rises and sets he will appear to do so almost at the same
point of the horizon each day.

(Rev.1 M. DAVIDSON, B.Sc, B.A.

ASTRONOMICAL APPOINTMENTS.
To the Editors of " Kkowledge."

Sirs, — I read Mr. F. A. Bellamy's letter with great interest,
and many of us must agree with the justness of his remarks.

As a perfectly independent person I have often thought
that they manage astronomical appointments much better in
America, and that this accounts for the splendid work
accomplished there in late years. I believe the Americans
allow proved merit to guide their selections in some degree,
and thus their great telescopes can be utilized by the best
observers. If Barnard, Burnhani, Brooks, Swift and others
had worked in England they would ha%e had to content them-
selves with such appliances as their own private means could
provide. But in America their abilities were recognised, and
they were placed in positions where observational skill and
powerful instruments could be employed in combination. This
was, it is true, owing to the beneficence of Lick, Yerkes,
Warner and others, and it is, perhaps, curious that we very
seldom read of such benefactions in our own country. In
America it is not unusual to hear of liberal bequests on behalf
of astronomy, but in England large sums are rarely, if ever,
devoted to such a purpose. They are applied to building public
libraries, benevolent institutions, laying-out parks, or some
such purpose.

46

February. 1911.

KNOWLEDGE.

47

When British millionaires fittingly recognise the claims
of our sublime science, and apportion some of their wealth
in furtherance of its pro,:jress, then our countrymen will
be in a position to effect more rapid advances. The most
capable obser\ers should be gi\en the use of the largest
instruments, so that, from their work in unison with able
mathematicians, \aluable results would naturally accrue. It
is not often that a good mathematician is a master-hand at
observation. By mere examination in figures and eyesight it is
not always possible to discover astronomical geniuses, or the
men best qualified for astronomical observatories. Those
should be selected who have previously exhibited abilities of
a high order, and have gained experience necessary for the
best work.

\V. F. DFXNING.

SPECTROSCOPIC DOUBLE STARS.
To the Editors of " Knowledge."

Sirs. — In your N'ovember number a correspondent inquires
about the determination of orbits of spectroscopic double stars.
To elucidate this fulh- in popular language is not easy, but I
think the principle involved can be made clear. To take the
simplest particular case, and considering one component of
the binary system only, if during the period of one complete
revolution the four intervals between the moments of
maximum positive and negative \ elocities and the two zero
velocities in the line of sight be all equal, a little consideration
will show that the orbit must be circular, and the two
maximum velocities, positive and negative, will be equal. In
this particular case the data being insufficient to give a value
for the inclination of the orbit to the line of sight, the linear
dimensions of this orbit, which would vary inverseU- as the
cosine of this angle of inclination, and hence also the masses
of the stars, cannot be determined. In general the four
intervals are all unequal, and the two maximum velocities are
also imequal, and from a knowledge of these quantities and the
known law of variation of the velocity in elliptic orbits, it
becomes possible to calculate the inclination of the plane of
the orbit to the line of sight, and thence the dimensions of the
orbit and the total mass involved. It may make clearer the
conditions involved if it is noted that at the moments of
successive zero velocities in the line of sight the star is
necessarily at opposite extremities of some diameter of its
elliptic orbit, but at the moments of successive maximum
velocities in the line of sight this is not so, but the positions
are shifted to points in the orbit where the absolute velocities are
greater, that is, to points nearer to the focus in which the centre of
gravity of the system lies, and it is in effect these shiftings (which
depend in amount on absolute velocities in the orbiti, which
make possible a solution of the problem. The case of a circular
orbit considered above illustrates this, for since the absolute
velocity in the orbit is constant, the positions in the orbit
which give the maximum velocities in the line of sight are not
shifted, and the problem is indeterminate. Practically in any
case the solution depends on the determination of six quanti-
ties, the four intervals and two maximum velocities. To
determine these with the greatest accuracy numerous obser-
vations at successive intervals of time are necessary. Needless
to say, the measurements are of the utmost delicacy, and the
proper combination of them makes a problem of great
complexity. So far, only one component of the binary system
has been considered. In all cases the orbits of the two stars
are similar ellipses with a common focus, and in the same
plane, but with their major axes oppositely directed, and if each
component gives a measurable spectrum, the orbits and
masses of both become completely known, but if one is a dark
body or too faint, it is only possible to determine the orbit of
the brighter component and the sum of the two masses. In
cases of variables of the Algol type, the variation of the light
during the partial eclipses gives further data from which some
idea of the volumes of the stars can be obtained.

The degree of attainable accuracy varies very greatly in
different cases ; the most favourable conditions are when the
orbits are much elongated, the period short, and the inclination

of the plane of the orbits to the line of sight small. I beUeve
that in the majority of well-observed cases the elongation of
the orbits is considerable, and this \\ ould suggest an origin for
these systems very different from that oi our solar system.

THI-:

INCLINED
VERTICAL

POSITION OF THE
.MERIDIANS OF THE

J. H. G,

APPARENT

EYES.

To fite Editors of " Knowledge."

Sirs, — In answer to the communication entitled " Sloping
Images" in the December number of "Knowledge," page
476, the facts are as stated. The whole subject of binocular
vision is treated in the most thorough manner by Helmholtz
in the " Physiologische Optik " ; Leipzig, 1867. The chapter
on binocular double vision begins at page 695 ; but I should
recommend the student to consult first the historical resume
at page 762. The discussion of the vertical meridians begins
at page 703 ; a number of measurements are given, and the
inclination of the apparent verticals is deduced at about
Zi' for normal eyes (705). Perhaps the most important
suggestion is on page 715. I must premise that by the word
" horopter " is meant the locus of points seen with both eyes
as single points. The general form of the horopter is
complex, and is the subject of abstruse mathematical investiga-
tion ; but, in the particular case of a man standing or walking,
looking straight before him, the horopter reduces to a plane,
which practically coincides with the ground, as seen in this
position. The distance of this plane from the eyes is governed
by the convergence of the apparent verticals ; and the point
in which they intersect is the point of the horopter which lies
near the feet. Helmholtz then suggests that the necessity,
which exists in walking, of having clear vision of the ground
where the foot is to be set, may be the origin of the conver-
gence, and thus of the inclination of the apparent verticals.

The word " horopter " is derived apparently from the Greek
w ords. opos. a line, boundar\', land mark ; and ottttip. a seer,
one who sees. The meaning does not obviously follow ; but
Helmholtz clearly means by it, " the assemblage or locus
of points seen as single." The word was originated by
.•Vguillonius, who used it to denote a plane, on which he
supposed everything seen to be projected.

The subject is of great extent and great interest. There
may, probably, be more modern developments, and there
should certainly be some English book on the subject : but I
do not know of anv.

R. H. M. B.

THE MOON AND THE WEATHER.
7"o the Editors of " Knowledge."

Sirs, — You were good enough to insert in your September
number a letter of mine on "The Moon and the Weather."

This year I have w-atched again, and carefully, and send
you the readings below, taken 6 a.m. and 1 p.m.: —

Dec. 1

1 .,

.. 33-

-40

2

.. 38-

-38

3 .,

,. 31-

-39

4 .

.. 28-

-30 ..

,. li" snow

5

.. 32-

-40

6 .

.. 32-

-38 .,

.. Snow, sleet, mist

7 .

.. 32-

-30 .,

.. Bright sunshine

8 .

.. 40-

-42 .,

Warm rain cleared off
snow from fields

9 .

.. 38-

-42 .,

.. S.W. wind

10 .

.. 34-

-38 ..

,. N.E. to S.W.

11 .

.. 26-

-40 ..

. N.E. to S.W.

12 .

.. 40-

-47 ..

.. S.W.

13 .

.. 36-

-42 ..

,. N.E. to S.W.

14 .

.. 33-

-42 ..

,. N.E. to S.W. Fog on
the river

15 .

.. 29-

-37 .,

.. N.E. to S.W. Fog
higher up

48

KNOWLEDGE.

February, 1911.

Dec. 16 ... 38—38 ... X.E. toS.W. Fog higher
,. i: ... 34—40 ... X.E. to S.W. Fog on

t^ip of inount.'iin.';
„ IS ... 34—36 ... Ditto

,. 19 ... 34—36 ... Wind X.E. to S.W No mists
„ 20 ... 28-36 ... Ditto

„ 21 ... 31—40 ... Ditto

., 22 ... 31 — 33 ... Snow from S.E. falling on

foot hills

Vou will see from tii.v .'jove that the high tides of December
may have something to Jo with weather here.

While writing m,-: ' ask, .^re there what are known as half
tides anywhere ex . on Pacific Coast — what are known as a
long run in and a . .lort run out and a short run in and a long
run out ?

Gl'X). DITCHAM.

THE ETERN.AL RETURN.
Tu the Editors of " Knowledge. "'

Sirs. — In a book by Mr. J, M. Kennedy, on the German
philosopher Niet^che, the following theory is promulgated by
the latter, the data being deri\ ed from the work of the great
French astronomer La Place ; and it appears that the same
theorj' was evolved independently by Blanqui, the famous
agitator, also Dr. Gustave Le Bon, and Heine, the German
poet, and is said to be found in Ancient Greek Philosophy. I
will endeavour to express it as succinctly as possible.

" Time and space are infinite, but the sum total of the
forces in the Universe appears to be constant and determined.
It is impossible to conceive their diminution or increase.
There is therefore a sum of constant and determined forces not
infinite. If these forces could ever attain a position of balance
it would have already happened, as an infinity of time has
passed, and the world would be for ever immobile, as it cannot
be conceived that once attained such a state could alter. The
sum total of these forces will bring about in infinite time a
vast number of combinations, and produce some that have
already been realised, and therefore the entire series of
combinations that have existed. Universal evolution brings
about the same phases, and travels round in an immense circle
for all eternity, from which it follows that every identical
individual has already lived the same life an infinite number of
times and will continue to do so for ever." Dr. Le Bon
expresses it thus: "If it is the same elements of each world
which serve after its destruction to create a new one, it is easy
to understand that the same combinations, viz., the same
worlds inhabited by the same beings, may be repeated time
after time, the possible combinations being limited and time
unlimited."

I write to ask is there any Haw in this reasoning, and if so
what is it ? This theory seems to me to pre-suppose that every
world is destro3'ed by collision with another before being
renewed, but as space is infinite it is difiicult to understand
why a dead world may not continue to travel for ever without
coming in contact with another. What ground is there for
thinking that the sum total of the forces in the Universe is
constant and determined ? In an infinity of space one would
suppose that these forces nuist per\ade infinite space, as
absolutely vacant space seems unthinkable. Wliat is the
opinion of scientists on the subject ?

H. D. B.\K(■LA^■.

PoDURA SCALi:s.
To flic Hilitors ((/"Knowledge."

Sirs, — In reply to Mr. 1. L. Smith's correspondence it is
quite evident he has "blundered greatlv."

It is not sufficient that his 1-4 objective, with cedar oil to
the cover glass, be coiuiected with the scale, in what Mr.
Smith believes to be optical contact, to obtain an aperture of
1-4, but that the cone of light which impinges upon the
scale shall also ha\e as large an angle. Xow this is

impossible with scales simply mounted in air; the way Mr.
Smith has his mounted (what other medium does he suggest
is between the cover glass and the slip?) even supposing the
scale really was in actual contact with the cover all over — he
will understand I cannot possibly agree that this is so under
the circumstances appertaining — beneath the scale and above
the glass slip is — what? Air? Xow, even if using an oil
immersion condenser of 1'4 made homogeneous with cedar oil
to the slip, so soon as the cone of light had passed through
this, into the air space — however small — down would drop the
aperture to 1-0, as air cannot possibly convey a greater angle
than this between two parallel siu'faces.

This fact is used as the standard or starting point of
refractive indices, and known as the "normal of air." If.
again, he had the scale mounted dry between two cover
glasses, as he says, truly this would make " confusion worse
confounded " ; in the first place it would simply throw his
condenser out of correction, as they are all corrected for a
certain thickness of slip, and should he have used a. dry
condenser he would have had two layers of air instead of one
for the light to pass through. It is quite evident he has
forgotten one of the principles of microscopic vision, and that
is, it is not the actual object he sees when looking through the
eyepiece, but simph- an image of that object formed some
distance up the tube of the microscope, and given an incident
air angle of I'O upon an object it would not matter if an
objective of 2-40 were immersed upon it — the resolving power
would be no greater than 1-0. Again, if, when looking down
the tube he thought he was getting 1-40 N..A., and which I
ha\ e showqi could not possibly be more than TO, he further
closed this aperture until only three quarters of that opening
was visible, he was actually getting much nearer '75 than T40.
an aperture not so great as a good dry ([uarter inch objective
would have given him as regards resolving power. The cover
glass idea might also be shown to be fallacious from the very
fact that such a small stratum of .air intervenes, apart from
condenser uncorrections.

There is an axiom also which seems so often neglected, that
the visibility of very minute structure is proportional to the
difference between the refractive index of the object and the
medium in which it is immersed, — which I particularly tried to
emphasize in my previous letter — and that it is essential if
the whole aperture of an objective is to be utilized to mount
such minute structures in some medium other than air. As
this has never been done successfully (so far as I am aware)
with the Podura Scale he will be able to realize what I mean
when I say that " here, then, we make no advance upon the
very earliest methods." Until such a medium is found and
the scale successfully mounted, we are left with the only
alternative in contrast between the TO of air and the T5 of
the scale itself, a practicability of vision of -5 only. It may be
— I cannot say — that with vertical illumination a slightly greater
angle than TO might be obtained, but that, it seems to me,
would only help us with surface structure chiefly, and as this
runs one into the province of the optician's art, 1 cannot
venture to trespass.

I ha\e not yet heard of a dry objecti\e which can give an
aperture of TO, and Mr. Smith's explanation of the "tilted
light to the object " in the microscope and the " moon it is
that revolves " are really too ab,struse for me.

In conclusion, I nmst apologise for my photographs being
too small for good reproduction, but if Mr. Smith would allow
the Editor to forward me his address, I should be pleased to
send him an actual enlargement of them, which would allow
him a much clearer view, I feel sure, than he can have at
present of their purport. I am obliged for his open remarks
and candid reply, and would like respectfully to suggest this
little experiment for him to make : take a slide, say, of
Pleiirosignia or Amphiplcura. mounted in Realgar, and using
his T40 objective immersed upon it. also a good condenser of
T40 immersed to the under slide of slip. Xow when the
object is in focus and the light axial, take out the eyepiece and
measure the diameter pf light coming through the objective —
then, take away this slide and substitute the slide of Podura,

Febri'arv, 1911.

KNOWLEDGE.

49

mounted dry on cover of the glass slip, using the same
immersion objective and condenser, and when in focus upon
the object, again taUe out the eyepiece and remeasure the
diameter of light coming through. 1 think when he has
thoroughly mastered this apparent elasticity of his 1-40

objective, he will have made wod progress in the study of
aperture, and, I trust, pardon me for the suggestion.

Yours faithfully,

F- J. W. PLASKITT.

QUERIES .A N D A N S W E R S.

Rciidcrs tii\- iiivifccl it) send in Oiicsfioiis and to ansic'cr the Queries wliich are printed on tliis prge.

gUESTIONS.

Numbers 16, 17 and IS (December number, page 461). and
21 (January number, page 39) still remain unanswered.

26. LUNAR ECLIPSE.— What, for parallel red rays, is

the inininnini length of focus of the Earth and its atmosphere,

regarded as a centrallv-stopped lens ? .

° ■ ^^ IsiS.

27. MINOR PLANETS.— Excluding the Berhn Vear-Book
as being rather too expensive, is there any yearly publication
which gives the ephemerides of the first score or two of the
brighter Minor Planets, or of any of them whatsoever beyond
the first four ? Mention of the price and place where
procnrable would oblige.

IsiS.

REPLIES.

10. WATER AND ITS OWN LEVEL.— In Mr. Mercer's
reply (page 39) the word not in the concluding phrase was
omitted ; it should have read : " While in the wider sense we
must also " not " forget that the earth has a great power of
attraction, and so the gravitation of the earth makes the
oceans take the shape of the globe."

10. If a level snrface is defined as a uiathcmaticall\- plane
surface then, except in imagination, no such thing exists in
nature, and " water finds its own level " is neither true nur
false, but simply meaningless, no definite level surface existing
from which to measure. The curvature of a puddle is exactly
the same as that of a still ocean, and if by level is meant the
imaginary plane which touches the surface of the water at a
given point, the statement that water finds its own level is
false, but it is very approximately true for distances which are
very small compared with the radius of the earth, and it is in
this restricted sense that it is used.

J. H. G.

20. THE DISTANCE OF THE SUN.— 1 think it may be
asserted categorically that no reward ever has been, or ever
will be, offered for the discovery of a more accurate method of
determining the sun's distance. Offers of reward are not likelv
to elicit new methods in abstract science.

This distance is probably known with an error of about one
part in two thousand, that is, about two feet and affew inches
in the mile, and if anyone discovered a new method which
would reduce this error by even so much as six inches, I
imagine the corrected distance would have but faint interest
for any scientific man, it would be the one thing in the
discovery of little moment, since it would certainly shortly be
further corrected. The discovery of the novel method itself is
quite another matter, and might well be of the greatest
importance being almost certainly capable of application
in many directions ; as to the discoverer, he would probably
feel the discovery itself sufficient reward. The Edisons
and Marconis of the world are usually made of stuff
that knows how to find its own reward, and no one
grudges it them ; the world has need of such : but the gifted
discoverers of new methods in science look for their reward in
a different direction, and I fancy are generally fairly satisfied
with what they get, though it may not have been so at all

stages of the world's histor\. It is always dangerous to
prophesy, but seems hardly Hkely that any really novel -.-.lethod
will be discovered. What is certain is that the use and
development of the already known methods will continually
reduce remaining error, and not improbably the next few years
may see even more than the six inches mentioned above
wiped out.

H. G.

22. RADIUM. — It is now accepted that radumi is a dis-
integration product of the element uranium (at. wgt. = 239).
In minerals, the ratio of radium to uranium exhibits a
constancy, as the former element has had time to reach its
equilibrium amount. This ratio appears to be about 3'S X 10-7
gram per gram of uranium. Owing to the comparatively
feeble activity of uranium, its period {i.e. time of half-trans-
formation) is enormously long, — about 5X109 years, and
certain products intervene between it and radium, viz: Ur. X
and ionium. Uranium, therefore, passes into radium through
intermediate stages, and so long as these disintegration
products remain associ.ated with the uranium in the mineral,
radium and all its disintegration products are maintained in
their equilibrium amounts, while all non -;>.ctiye products
gradually increase. In this way the a particles (atoms of the
gas helium, (at. wgt. = 4.), become occluded in radioactive
minerals, and this occluded helium increases in quantity with
time. The theoretical rate of evolution of helium can be
estimated with fair accuracy, and by comparison of the
calculated annual evolution of helium per gram of the mineral
with the actual amount found occluded in it. an estimate of
the age of any active mineral can be made. The method may
not be entirely free from uncertainty, but there can be little
doubt of the general correctness of the values found, which
amount in some cases to hundreds of millions of years.

As to the origin of uranium itself, it is hardly possible to
speculate. As no element of higher atomic weight is known,
we cannot assume it to be a disintegration product. The
same question as to origin might be asked of any element, —
we have always the problem of the evolution of the elements
before us.

Charles W. Raffety.

23. THE GULF STREAM.— It is thought now, by many
of those who have studied the subject, that the influence of
the Gulf Stream on the climate of the British Isles is by no
means so great as was formerly believed to be the case.
Owing to investigations made in the North .\tlantic ocean, and
examinations of samples of sea water taken by the "Challenger "
and ■■ Michael Sars " Expeditions, it is found that the Arctic
Current which flows past the coast of Labrador cuts into
the tropical water brought north by the Gulf Stream off
Newfoundland, and considerably modifies the temperature.

The question as to how much of the actual current from the
Gulf of Mexico crosses the Atlantic is a complex question,
and requires further investigation, for it is found to vary at
different times.

The clim.ate of the British Isles is largely aftected by the
eastward drifts from the North Atlantic, which consist of
heated waters from the Equatorial regions, and these flow
north-eastwards as a warm snrface current into the .Arctic
Seas.

F. Ross Thomson. F.R.G.S.

50

KNOWLEDGE.

Fkbruarv. 1911.

24. DREAMS. — I am convinced, after twenty years of
experience, that the scientific position with respect to dreams
is, that they may have an objective as \vell as a subjective
origin, J, C. W,Tightly says '' expects and it happens " ;
we hear coming upon our sleeping horizon, " Here is the Queen
of Heaven."' and we wake to find the full moon beaming into
our faces ; the sensation experienced between the sleeping and
the waiting is as a centripetal concentric curtain shutting.
Such are common to those v.ho enjoy or suffer from a cosmic
telepathy ; an intelligence sensed as within and without, and
which communicates with the clairaudient. often to his dismay
and terror, Interpretatic:. should be guarded ; the phenomena
are certainly not always subjective. We know this is the
case by such experiences of a sensed expectation becoming
a realisation occvr.i lag as the lower notes of a gamut, of
which the higher r.cles are an inter-communication of brain to
brain as perfect as a telephone, and which is known to
theosophists and others. The most scientific book on dreams
is bv Dr, Sancte-di-Sanctis, " I Sogni," but his first edition in

not recognising the objective possibility of dreams, is. like the
great classic books on psychology and mental pathology,
deprived of half its value. To those who know first-hand
telepathic phenomena, there are no secrets which can be
hidden, and the demonstration of a disembodied intelligence
is ever sensed and accepted by them as an elementarv natnral
phenomenon, not of necessity spiritual, but a form of radiant
energy, and to which a few may possess the key — even human
beings. J. B. S.

25. TIDES. — J. H. G. has made some slip in his question,
when he says that with deep oceans the tidal protuberance
should be behind the moon with direct Tides. I think that,
perhaps, if he re-reads pages 240-242 of Darwin's Tides he will
see that he is mis-stating the facts. He is unquestionably
right in saj-ing that the whole subject might, with advantage,
receive more notice in popular accounts. I may refer him to
'■ Chapters in Astronomy." by Claudius Kennedy.

J. A. H.\RDC.\STLE.

SOLAR DISTURBANCES DURING DECEMBER. 1910.
Bv FRANK C. DENNETT.

December has been marked by a still further decrease in
solar disturbance. On six days out of the twenty-three on
which it was found possible to observe, no spots, maculae or
faculae, were visible, and on six others only faculae were
noted. At noon on December the 1st, the longitude of the
central meridian was 342° 52'.

dwindled away from the 18th until the 22nd, when last seen,
-A faculic disturbance was observed in the same area on the
29th, which may possibly have contained a pore.

No, 91, — .A pore amid a small faculic disturbance, only
recorded on the 2Sth,

The chart is constructed from the combined observations

DAY OF DECEMBER,

17

1

^^

^5

*

^3

22

2

2f

19

IB,

17

;6.

15

K.

13

l_

1

IQ

9

B

7

S.

4 3

_ i

30 2

29

'•, ?«

90

y

50

89cL

89

20

'

1"

4

m

20

50

91

rcn

M-

10 20 50 »0 50 60 TO 80 50 100 110 120 130 140 r50 l60 170 180 190 200 210 220 250 240 250 260 270 280 290 300 310 320 330 3«1 550 360

No, 89, — A group of three larger pores with smaller points
close up, seen on the 1 1th ; after slight changes it had dwindled
to a poorly-seen marking, on the 1 5th, when last observed.

No. 89<T. — A triangular group of spotlets, from the 11 -13th ;
the rear spots were not seen after, but pores had developed in
front of the preceding one on the 14-16th, but it was not seen
after. The length of the group was 30,000 miles.

No, 90, — A small spot had come round the eastern limb and

of Messrs. J, McHarg, .A. .A, Buss, E. E. Peacock, and F. C.
Dennett.

The second chart shows the distribution of the dark spots
upon the entire surface of the sun during the whole \^ear.
Ninety-one primary and thirty-one secondary outbreaks, of
which eighty-nine were in the southern, and thirty-three in the
northern hemisphere. It will be noted that certain areas
appear to be far more subject to disturbance than do others.

DISTRIBUTION OF SPOT DISTURBANCES DURING 1910.

B

-^

© $ ,

30

'0 BO 90 100 MO 120 130 l«) 150 160 170 180 190 200 210 220 230 Z¥> 250 260 270 2B0 290 500 310 320 330 340 350 360

10 20 30 V' 50 60

BRITISH EARTHQUAKES.

Bv CHARLES DAVISON. Sc.D.. F.v .>

E.\RTHyuAKi-:s, according to their nature and origin,
may be divided into three classes — simple, twin and
complex. In simple earthquakes the shock seldom
exceeds a few seconds in duration, and its intensitx'
increases to a maximum and then dies aw aw In
twin earthquakes the shock consists of two distinct
parts, separated by an interval of rest and quiet,
lasting, as a rule, for two or three seconds, each part
resembling a simple shock in nature and duration.
Complex earthquakes are usuallx- of considerable
duration and great violence. The\' ma\' last as long
as three or four minutes, and there are man\-
fluctuations of intensity and frequent changes of
direction. Corresponding to this difference in nature
there is also a diversitv
in origin. In simple
earthquakes the focus
consists of a single region,
near the centre of which
the initial impulse is
greater than elsewhere.
In twin earthquakes there
are two such regions, I-,
almost or completely de- FiGUKii 1.
tached from one another.
In complex earthquakes
many portions, which ma\

connected, and the violence of the shock is due
partly, as in simple and twin earthquakes, to the
friction of sliding rock-surfaces, partlv to the rapid
translation of the rock-masses themseK'es. In other
words, the movement which gives rise to the shock
is not as a rule permanentlv perceptible at the surface
in simple and twin earthquakes, while in complex
earthquakes it often remains manifest in the form of
fault-scarps and horizontal displacements.

\Miate\-er mav ha\'e been the case in times jiast,
this countr\- is now. fortunateh', exempt from all
earthquakes of the complex order. Occasionally,
about once in ten years, a shock causes damage to
houses within a limited area, but the houses affected
are usually of an inferior class. The great majoritv
of our earthquakes are so slight that they would have
passed unnoticed if the\- had not occurred during the
hours devoted to rest and sleep.

Frequency.

During the last twenty-one years (1889-1909). in
which the greater part of my spare time has been
devoted to the study of British earthquakes, the total
number know n to me is 250, or almost exactl\- one a

month. The number of disturbances described as
earthquakes in newspapers is of course considerabiy
larger, but many of these disturbances prove on
in\'estigation to be artificial or parth' artificial in
their origin. Many of them are caused h\ the firing
of heavy guns at a distance, their true character
being generally revealed by the explosive nature of
the sound, the apparent transmission of the waves
through the air and not through the ground, and by
the increasing confidence with which observers in
one direction attribute the shock and sound to gun-
firing. Others are due to the explosion of
meteorites ; a few. and their spurious origin is soon
detected, to the explosion of dynamite or powder

magazines. An interest-
ing class of local shocks
is found to be confined to
mining districts. The\'
are often of considerable
intensity within a ver\'
small area, but are im-
perceptible at a distance
T.-. ot a tew miles from its

A curve shewing the number of shocks felt centre. The\' ma\' some-
in this country at different hours. ji,^^^^ " ,^^ ^.^^^^^j " ^^. ^^^

fall of masses of rock from the roof of the
workings, but most of them ajjpear to be caused
by slips of the superincumbent strata along a fault-
surface, the slips being started by the withdrawal of
rock from the workings or b\- that of water in

the focus consists of
or nia\' not be directh'

pumping. During the last twenty-one }-ears not less
than seventeen local shocks are probabK- due to this
cause.

Now, just as many slight shocks are wrongh'
confused with earthquakes and must be eliminated
as far as possible from our earthquake-catalogues, so
a large number may also escape detection, or, at any
rate, record. They may be attributed to artificial
operations, such as blasting, gun-firing, thunder, or
the passing of a distant train or vehicle. There is
other e\'idence than mere probable supposition.
The cur\'e in Figure 1 illustrates the number of
shocks felt in this country during the different hours
of the da}-. It show s that the\- are recorded more
frequentl}' during certain hours, and especialh' from
1 to 2 a.m., 4 to 5 a.m., 4 to 5 p.m., and 9 to 11
p.m. But the varying frequency is, in all probability,
more apparent than real, All earthquake-catalogues
founded on personal, and not instrumental, records,
show the same increase of frequency late in the
evening and in the early hours of the morning. It
is no doubt due to more favourable conditions of

51

KNOWLEDGE.

February. 1911.

The streets -vce quiet, observers are

iiig down, ari ^, 'hen they awake, as

:::12 a.m.. the\- are in a

^j are alert and read\- to

,ent. The increase in

.ill. seems to be due to

the sixteen earthquakes

.UHir. seven occurred on a

-1 ethers possibh' in the restful

' an early tea. Now. as shocks

.talh' show a tendencN' to cjreatest

observation
generall)- i'

persons ;>ften do between
nervor.s condition, their i
detect the slightest '::■
frequencv from 4
similar condition
.ecorded duriuL'
Sunday afternoii
interval devoted
recorded instru-

bc^ local noon at an\' place, it follows
: • shocks, which are onl\' perceptible
conditions alluded to abo\'e. must be

frequenc\- a
that the" ':
under i^e
much more numerous
than our catalogues would
lead us to suspect. We
si I all probably not be
over-estimating their
number if we consider
that t\\cnt\- earthquakes
occur in this countr\- on

Pkriodk'ity.

^^'hether there be anv
real \ariation of frequenc\'

3^1

throughout the da\- must
for the present remain
uncertain in the case of British eartlniuakes. Eor
this purpose the only records of any value are those
which are registered by properly erected instruments,
isolated completely from all artificial disturbances.
Personal obser\-ations are. however, sufficient to
determine whether any annual variation exists in the
frequency of earthquakes, for there is no reason for
supposing the conditions of observation to be sensibh-
better at one time of the year than another. In
Figure 2. the continuous line represents the numbers
of earthquakes recorded during the different months,
account, of course, being taken of their varying
lengths. The curve, it will be seen, is irregular, the
monthly number of shocks being greatest in
September and December. The actual frequenc\- of
earthquakes may, however, be due to different
causes, which ma\- be themselves subject to variations
of different periods. — just as, when a chord is plaved
on any instrument, the moxement of a particle of
air in its neighbourhood is compounded of several
movements, each with a different period correspond-
ing to those of the notes that are struck. To
.separate out the different periods which produce the
actual variation in frequency, some method of
harmonic analysis must be emploved. and, as great
accuracy is not essential, the method of overlappin;.

Figure 2. A curve representing the number of shocks
recorded in this country during different months of the vear.

the end of January : the mean of those for December
to Ma\' corresponds to the end of Februarv. and so
on. In this wa\" the broken line in Figure 2 is
obtained. The effect of taking six-monthl\- means is
to smooth the curve hv eliminating or reducing
periods of six months and less. The broken line
therefore, represents with sufficient accurac\' the
annual variation in tre(iuenc\- of British earthquakes.
The maximum of the annual period, it will be
noticed, falls in October, that is. in the middle of two
months when the actual frequencv is less than in the
two months of September and December on either
side. .\ similar method ma\' be used for determining
whether a si\-montbl\- period exists, but the resulting

\'ariation is not pro-
notmced enough for us
to feel convinced of the
realitx' of a period of this
length. All that we can
regard as proved is that
there is a marked annual
periodicitv, and that its
m a X i m 11 m occurs in
October and its minimum
in .\pril.

Intensity.

The intensitx' of an
earthquake is generally
denoted by its greatest
intensit\- within the central region of the dis-
turbed area. l'"or this purpose an arbitrar}- scale
is used, known as the Kossi-Forel scale. In
this there are ten degrees, the two lowest and
the two highest being inapplicable to the earth-
quakes here considered,
are as follows, onh
each heading : the shock being strong enough :
Intensity

3 for the direction or duration to be sensible ;

4 to make doors, w indows. and so on, rattle ;
.T to cause the observer's seat to be percep-
tibly raised or mo\-ed :

6 to make chandeliers, pictures, and so on,

The remaining degrees
one test being given under

7 to overthrow ornaments, vases, and so on ;

8 to throw dow n chimnevs or crack the walls

of some houses.
Of the two hundred and hfty earthquakes, three
were of intensit\- 8. nine of intensit}' 7, se\'en
of intensitv 6, twenty-nine of intensity 5, sixt_\--four
of intensitv 4, one hundred and twenty-seven of
intensit\- 3 or about 3, while the remaining eleven
were mereh' sounds without any tremor being felt.
.\s a rule, of course, the area disturbed hv an

means will be be found sufficient for the purpose, earthquake increases w ith its intensity, the average

The method consists in finding consecutive six- disturbed area of an earthquake of intensity three

monthly means of the monthly numbers of being one hundred and twent\--six square miles, and

earthquakes. Thus, the mean of the numbers for of one of intensit\- eight about sixty-six thousand

the months from November to .Vpril inclusi\-e, square miles. Earthquakes of the same degree of

corresponds to the middle of that interxal, that is, to intensitv are, however, felt over w idely differing

February. 1911.

KNOWLEDGE.

53

areas. For instance, for the intensit\' seven, the
disturbed area ma\' be as lo\\' as one thousand square
miles and as high as sixty-three thousand six hundred
square miles ; for the intensity six. the area ranges
from seventy-four to three thousand one hundred
square miles ; and so on. Thus, actual intensitv
near the centre cannot be regarded as a measure of
an earthquake's strength. Nor, on the other hand,
as some seismologists maintain, can the extent of
the disturbed area be employed as such a measure.
for this area depends on several conditions, of which
one of the most important is the time of occurrence.
For instance, the Pembroke earthquake of 1892 was
felt over fort\-four thousand eight hundred and sixtv
square miles, and the distinctl\- weaker shock of 1S93
over sixty-three thousand six hundred square miles,
the reason being that the former movement occurred at
0.24 a.m. and the latter at 5.45 p.m. In like
manner the disturbed areas of the Derby earth-
quakes of 1903 and 1904 were twelve thousand and
twenty-fi\e thousand square miles, the former
occurring at 1.30 p.m. and the latter, which was
somewhat weaker, at .).21 on a Sunday afternoon.
In each case the disturbed area of the earlier shock
was bounded by a line of intensity four, and of the
latter by one of intensity three. On the whole, if area
is to be used at all as a measure of strength, it would
seem better to employ the area within a given
isoseismal line, or line of ecjual intensity, say that
corresponding to intensit\- four. F'or British earth-
quakes it is convenient to regard as straii!^ all those
in which this area exceeds five thousand square miles,
as moderate all those in which it lies between one
thousand and five thousand square miles, and as
slif;lif all those in which it is less than one thousand
square miles. Making use of this convention it
would appear, then, that during the twenty-one years
considered there ha\e been in this countr\' nine
strong, seven moderate, and two hundred and twenty
three slight earthquakes, and eleven earth-sounds.

DlSTKIlU"TI()X.

There is \-ery little apj)roach to unitormit\- in the
distribution of British earthquakes. Some parts of
the country are frequenth' visited, others onl\- rarelw
or not at all. Thus, of the total number, fifty
originated in England. twenty-se\en in Wales, and
one hundred and seventy-three in Scotland. In the
latter country certain limited districts are subject to
numerous shocks. Thus, in the low-l\-ing countr\-
between the Ochil Hills and the P'irth of Forth
eighty-three shocks were felt, several of them of
intensities six and seven ; in Cilen Garr\', in
Inverness-shire, fort\"-one shocks, all of them slight ;
while, in the small tract Iving along the line of the
Caledonian Canal between Inverness and Loch Ness.
thirty shocks originated, two of them disturbing areas
of seven thousand five hundred, and thirt\--thrce
thousand square miles.

In England, the country between Hereford and
Ross has been visited by thirteen shocks, one of
them the strongest felt in this country during the last

quarter of a century, in whichever wav strength be
measured. In Derbyshire, betw^een Ashbourne and
\\'irksworth, eight earthquakes havo occurred, two
of them strong. Other parts ot 'he country are nut
specially favoured, with the excep^' on perhaps of the
county of Corn-,' all, to which ten si.^'it shocks must
he credited.

Tlie Welsh ea> iquakes are occasioi Ih' > !; con-
siderable strength. '.'I "y occur for the m::.?: pa,rt in
three districts, one b ing in the north- ; ;:t cf
Carnarvonshire, the othii^ in the south ot ■.hs
country, in Pembrokeshire and Glamorgan. Th
number among them four of the nine strong edth-
quakes, and all four, it mav be noticed, were felt
across the channel in the eastern and south-eastern
counties of Ireland.

Only a small part of Great Britain has been
undisturbed by any sensible earthquake during the
t\\ent\'-one years, the only unshaken districts being
the extreme north-east of England and the southern
part of Scotland. The greater part of Ireland has
entireh' escaped from all terrestrial disturbance, and,
so far as I know, not a single earthquake has actually
originated during the inter\al considered \\ithiii the
area of this island.

NATrRi-; OF THK Shock and SorxD.

The first intimation that we generall}- receive of
the coming earthquake is a low rumbling noise.
\\'ithin a second or two, as the noise grows louder,
a tremor begins to be felt, the separate vibrations
being small and occurring at the rate of about five or
six a second. Within two or three seconds these
merge into the main part of the shock, consisting of
larger vibrations or jolts, with a period of perhaps
one-third of a second and a total range, even in the
strongest earthquakes, of probably only a fraction of
an inch. Close to the centre these vibrations have
been described as like the fierce beats of a railway
engine travelling rapidl\" ; but at a distance of fift\'
miles or more they become smoother and slower,
like the movements felt in a carriage with good
springs. During the whole of this time the rumbling
sound continues, becoming louder and more grating
with the principal vibrations, and occasionally inter-
spersed with deep explosive crashes. .\s a rule the
strong vibrations begin to die away after two or
three seconds, and are succeeded by a weaker tremor
and noise, until, finall\', after the lapse of six or
eight seconds, both die away, the sound continuing
for perhaps a second or two after the shock. The
total duration of the shock in a strong earthquake is
thus from six to eight or nine seconds.

In slight earthquakes the phenomena are much
simpler. Sometimes only a tremor is felt, lasting
for at most two or three seconds, and accompanied
b\- the usual ruml)ling noise: but, as a rule, among
the tremors, and generally at the beginning, one
prominent vibration is felt, so that it seems as if a
heav\- weight had fallen with a thud upon the
ground, with the brief quiver following as such a
thud might be expected to cause in a building.

54

KNOWLEDGE.

February. 1911.

The sour.J w hich forms so essential a part of an
earthqual'c is -a low, ru'nbliv^g or grating noise.
Near the centre it is henr.i by all observers, but as
the distance increases it becomes inaudible to a
larger and larger perc_ itr;;;- of persons. The reason
is that the numbe- r_ brations occurring everN-
second is very ne;!r lIi which forms the lower limit
of audibility, or a:~.;t sixteen to thirt\--t\\o a
second: and. uit'p ; slight decrease in strength,
these vibrations il to affect the ear. Moreo\'er,
this limit varit i different persons, so that some,
and not ot'i : are able to hear the sound. Thus,
in one :_. and even in the same house, one

observe: will tleclare that the shock was unaccom-
panied by sound, while another will record a noise
louder than thunder or than main- traction engines
passing together.

Some obser\-ers tiiui it liifficult to describe the
^ound. remarking that it resembles no noise with
which they are acijuainted. The majorit\" compare
it to some well-known t\"pes. Those most frequenth-
referred to are the rapid passing of heav\- waggons,
traction-engines, steam-rollers, or railwa\' trains, on a
hard road, over a bridge, or through a tunnel : the
deep roll of thunder, and generally distant thunder ;
and the rising of a strong wind or a chimne\' on hre.
Less frequentl}' in strong earthquakes, but more
often in slight ones, we hax'e comparisons to sounds
of short duration, such as the tipping of a load of
stones, the fall of a heav\- muffled weight, the firing
of a distant gun. nr a blast in a quarr\-.

By most obserxers, by two out of ex'ery three.
the sound is heard just before the shock begins.
A smaller proportion, about two out of e\'er\- five.
hear the sound after the shock is over. In man\"
foreign countries the sound is heard before the shock
only, and this has led to the impression that the
waves which form the sound tra\el more rapidh'
than those w hich form the shock. The true explana-
tion of the discrejiancy is that the British, as a race,
are more capable of hearing low sounds than most
other people. Tliey possess a lower limit of audi-
bilit}', which, in earthquake-countries. ma\- be of
service in enabling them to escape into the open air
with the first rumble of the on-coming earthquake.
That the two series of waves travel with ajjpro.xi-
mately, if not quite, the same velocity is evident from
the fact that, in strong earthquakes, the percentage
of observers who hear the sound before the shock,
and also of those who hear it after the shock, is
almost exactly the same at all distances from the
origin. If there were any appreciable difference in
velocity, the sound and shock would soon become
separated from one another.

Simple and Twin EARTHguAKES.

The great majorit}- of British earthquakes belong
to the first of the three classes mentioned at the
beginning of this paper. Of the two hundred and
fifty earthquakes, two hundred and thirt\-nine
were simple, and ele\en twin. The latter include,
however, most of the strong shocks felt in this

country. Of these, nine in number, two were
simple earthquakes, the average area disturbed by
them being twent\--nine thousand square miles. The
remaining seven were twins, and disturbed, on an
average, an area of forty-seven thousand square miles.
The latter include also the four strongest earthquakes
of the period considered, namely the Pembroke earth-
quakes of 1892 and 189j. the Hereford earthquake
of 1896, and the Swansea earthquake of 1906. The
average disturbed area of these four earthquakes is
sixty-eight thousand square miles, or three-quarters
of the total area of Great Britain.

.-\nother point in which simple and twin earth-
quakes differ is in the number of minor shocks which
attend them. The total number of such shocks
during the twenty-one \'ears is se\ent\-one. all but
five of which preceded or followed the nine strong
earthquakes and the Inverness earthquake oi 1890.
This earthquake, which belongs to the class of simple
earthquakes, just falls short of the test required to
place it among the strong earthquakes. The area
included within the isoseismal of intensity four, is
four thousand three hundred and fort\' square miles,
and the area disturbed by it about seven thousand
five hundred square miles. Of the sixt\--six minor
shocks which attended these ten earthquakes, fifteen
were fore-shocks and fift\'-one after-shocks : and, of
the after-shocks. thirt\"-three followed the three
simple earthquakes, and eighteen the seven twin
earthquakes. In other words, the average number
of after-shocks of a simple earthquake is eleven, and
of a twin eartlKpiake between two and three.

.MiNOK Shucks.

I5esides the slight shocks which are intimately
connected with the strong earthtjuakes, there have
been two series of shocks, for the most part of slight
intensity and confined to certain limited districts.
Both of these districts are in Scotland, and are
responsible for the large number of slight shocks
felt in that country. The first series lasted for about
twelve years, from 1888 to 1899, and were confined
to Glen Garrw a vallev in the west of Inverness-
shire. In this interval fift\' slight shocks ware
recorded, but owing to the mountainous character of
the district little more is known about them than
their time of occurrence and their nature at one or
two places. The shock was invariably a slight
tremor of very brief duration, and accompanied by a
sound compared most frequently to a carriage
passing, but occasionally to thunder.

The series of earthquakes felt chiefiy in the district
lying to the north of the Firth of Forth and south of
the Ochil Hills is more interesting, on account of the
larger number of observers, though here again the
presence of a range of hills to the north prevents us
from determining the disturbed areas of all but the
strongest shocks. This series began with four shocks
in the year 1900, and then ceased, with one excep-
tion in 190.3. until 1905. when both the number and
intensit\' increased. , In this year ten were recorded,
one of them being felt over an area of a thousand

February. 1911.

KNOWLEDGE.

55

square niik-s. In the four succeeding years, the num-
bers c)bser\'ed were nineteen, thirteen, seventeen and
eighteen, and they show no sign at present of abating
in frequenc\' or strength. During the ten years
1900-1909 the number felt was eighty-three. They
are interesting from their probable connection with
the great fault \\'hich skirts the southern side of the
Ochil Hills, which, notwithstanding its advanced age,
still seems to be growing. The small movements,
which give rise to the earthquakes, appear to be
limited to the portion of the fault between Airthrey
(near Bridge of Allan) and Tillicoultr\-, and to take
place at a very small depth below the surface.

Observations in Mixes.

Isolated observations have been made in mines in
man\- cases, both in this and other countries, the
general result being that the shock is more feebh'
felt in mines than upon the surface of the ground.
Several recent I^ritish earthquakes have occurred
within or near mining districts, and these, especialh'
the Derby earthquake of 1903 and the Swansea
earthquake of 1906. have thrown further light on
an interesting subject. The\' confirm the pre\ious
impression that the shock is more manifest on the
surface than underground : indeed, the disturbed
area in mines is only a small fraction of that upon
the surface. On the surface, again, the sound in
strong earthquakes is heard over an area much
smaller than that within which the shock is felt.
In mines the sound is observed as far as, or farther
than, the shock. Some interesting observations were
made on the sound in mines in the two earthquakes
referred to. Thev show that the sound appears to
travel through the rock overhead rather than through
that below, but this is onh' the case at distances of
more than five miles from the centre. Again, in
both earthquakes, there is some, though not decisive,
evidence showing that the intensity of the shock
increases with the depth of the workings below the
surface. This point is one on which it would be
worth \\hile to make careful in\-estigations in future
earthquakes.

Origin of British Earthqu.vkes.

The most interesting result to which the study of
British earthquakes has led is the proof of their
connection with the slow growth of faults. The
longer axes of the isoseismal lines are parallel, or
\-ery nearly so, to the main faults of the central
district, or, if the faults be unmapped, to the prin-
cipal lines of folding. The centres of the earthquakes
lie on the side towards which the fault-surface is
inclined, and at a short distance (generally a mile or
two) from the fault-line. When manv after-shocks
occur, as with the Inverness earthquake of 1901,
their centres lie within a narrow band parallel to the
fault, and again on the side towards which the fault-
surface slopes. It is possible, indeed, to trace the
migrations of the seismic foci from side to side along
the fault, and gradual!}', as the series come to an
end, towards the surface of the earth.

The occurrence of true earthquakes in this
country i- therefore decisive e\-idence that the growth
of Britisl . faults, ancient as man\- of them are, is not
yet at an end. This is not the c;-.se, of course, with
all our faults. The great majority, are, perhaps, at
rest, possibly h:-\e altogether ceaseci to grow. But
some, it may be a very small minor ;.', have kept
themselves bj' constant, if slight, exertions free to
move. That the absciute displacements a. 5 of small
account is evident from the fact that the;; are so
seldom destructive to property. But the displaceu-.ent
to which any one earthquake is due extends ov.er a
considerable area. In the Carlisle earthquake of
1901 and the Swansea earthquake of 1906 the total
length of the focus exceeded twent\- miles.

The length of the focus of an earthquake can onh
be determined roughh' : in an\- particular case the
error ma\- amount to one, or several miles. But
there is a curious relation between the a\erage
length of focus in the different classes of earthquakes.
In strong earthquakes this average length is twelve
and a quarter miles, and in moderate earthquakes
thirteen miles. Slight earth(juakes may be di\'ided
into two well-marked groups. In one the focus is
nine miles or more in length, and the average length
tw elve miles : in the other the focus is six miles or
less in length, and the average length four miles or
less, b'urther evidence on this point is afforded by
the nature of the sound. Dividing the types of
comparison into two classes, according as they are of
long or short duration, we find that the percentage
of references to types of long duration is eighty-four
for strong earthquakes, eighty-one for moderate
earthquakes, eighty-four for slight earth(]uakes with
a long focus, and sixt\'-three for those with a short
focus. Thus, except for the slightest of all earth-
quakes, the average length of focus is practically the
same in all three classes. Their difference of
intensit\' depends only on the amount of displacement
witlnn the focus.

There must be some reason for this close correspon-
dence in average length of focus. What the reason
is cannot at present he definitely settled, though
it can be surmised. The late M. Marcel Bertrand
published a map of France on which are depicted
the courses of the anticlines and synclines of the great
folds which traverse the rocks of that country.
The average distance between successive anticlines
or crests, measured along several lines at right angles
to them, varies from nine to twelve miles. For this
countrv no similar map. so far as I am aware, has
been prepared. I>ut it is at least a probable
supposition that the a\-erage distance between the
crests of the great crust-folds does not differ widely
in the two countries. If this be the case, then it
would seem that the length of a crust-fold, or
distance from crest to crest, ma\- govern the length
of the displacements along the faults which intersect
them. In other words, the growth of the faults to
which our earthquakes owe their origin is at present
chieflv due to the gro%vth of the transverse crust-folds.

THE V--^ '/CAN OBSERX'ATORY OF TO-DAY

Bv W. ALl'Ki:i) PARK.

--.LTHOUGH It w::: ::.. antil comparatively recent
years that the ztv-.^n Observatory entered upon
that active ph;:.-e its existence uhich recognises
in it the well-' \vn and well-equipped Spccola
Vaticana of *'' csent day, it is. in realitw one of
the most ■-' Ae European institutions dedicated
to the s 'c- jf the heavenly science ; for its early
h i s t o r dates from a
peril'.: v, hich precedes the
four.aation of our own
na^onal observator\' at
' reenwich b\- nearh' a
century, w bile it can claim
intimate connection with
one of the most epoch-
making events in the
annals of Astrondiiu.
The significant appear-
ance on its official seal
of the Ram's Head, s\ni-
bolical of the sun's posi-
tion at the vernal equino.x.
still serves to com-
memorate this event —
the reform of the calendar,
under Gregory XIII—
\\hicb may, indeed, hv
said to ba\e called the
observatory, as such, into
being, as it was the
famous meridian line,
drawn by Ignazio Danti
about 1580, to demon-
strate to the Pope that
the sun no longer
entered the sign Aries
on the orthodox date of
March 21st, assigned to it
by the Council of Nicaea
in .\.D. 3i5. that repre-
sented the nucleus around
which astronomical in-

Tin

l-"lGlkl.
Astrographic

struments of all kinds soon collected to funn
the embr\-o of the present \'atican Observatory.
A reform of the calendar had been proposed and
discussed as early as 1414. but as the accumulated
error in Gregory's time amounted to more than
ten days, a circumstance which seriously affected
the date of Easter, the long-desired amendment,
projected by the Neapolitan astronomer, Lilio,
and more fully demonstrated by the Jesuit Clavius,
was established by Gregory in 15S2. who, by this
means, conferred a lasting e'chit on his pontificate.
As is well known, this reform, enforced
pain of excommunication "
Catholic workl. met with the greatest opposition in

under
throughout the Roman

those countries which did not recognise the papal
supremac}", and it was not adopted b\- Germany
until after the energetic representations of Leibnitz
and others in 1700, nor bv Great Britain until more
than half a century later, when its establishment by
Act of Parliament causedthemembersof thecalendar-
reforming government to be mobbed in the streets of

London by the populace,
w ho. imagining the\- were
being defrauded of their
natural rights, noisily
demanded the restitution
ot the eleven da^•s, which,
l>\ that time, had to be
suppressed in order to
Sit chronological matters
on an accurate footing.

Danti's meridian line
was contained in that
loft\' portion (d the
X'atican Palace known
as the Tone del Venfi,
and this " fiirris asfronnii
speciilatrix." as it was
referred to in the inscrip-
tions, remained for over
two centuries the onl}-
astronomical, as it was
until recenth' the princi-
pal meteorological, station
of the \'atican. The
output of work, however,
was at first but small
and intermittent, and
long periods of " repose "
alternated with sporadic
outbursts of activity, a
notable manifestation of
the latter quality occurr-
ing towards the end of
the eighteenth century,
when Gilii, by unremitt-
ing ihligeiicc ill obser\atioii. succeeded in restoring
some measure of prestige to the venerable institution,
which, it is interesting to find, had already acquired,
in addition to other notable instruments of
the period, a Dollond achromatic telescope from
England. Meteorological, howexer rather than
astninomical work now absorbed the energies
of the obser\ator\ . for it had been found that
the proximitx' of the great dome of St. Peter's
undul}- circumscribed its southern \-iew. thus
rendering the site less favourable for astronomical
observations than that occupied by the obser\atory
of the Collegio Romano, which had then but recently
{i.e.. in 17^7) been founded Iw Calandrelli. and

Refractor.

56

Figure 2. The Dome containing the sixteen-inch Refractor, and the Bridge connecting the Observatories.

Seen from the terrace o% er the riroiin of Lourdes. St. Peter's is on the right of the picttire.

tB^

Figure i. A nearer view ot the Refractor Uuine with attached dweUiiig hou.e, shcvvuig also olhci duuies

and the spire over the Lourdes Grotto.

3 8

KNOWLEDGE.

Frhruarv. 1911.

; recommendation of

■jion of the instruments

For an astronomical

its instruments would

which was later to become si, famous through the
labours of De Vico and h.i; illustrious successor
Secchi: ; nd t"hither, at
Boscovich,the astronomic i-
was accordingly transfjrrai
observatory to be depi'/.£-d j
seem sufficientl}- fat-l :.t i:i existence, but worse was
to follow. After the ;:5-::ical events of 1870. when the
Italian troops toe-, fr'nal possession of the Eternal
City, and Pius IX irntered upon his self-imposed
imprisonment 1!'. \'atican, the old To/vc (/e; Vcnfi,
owing to thr ; en demand for room, was tinallv
transformt dwelling apartments !

But a ._,i! as resurrection was now approaching.
When Leo XIII celebrated his jubilee in 1888. a
scientinc exhibition was held in Rome to celebrate
the e-v'ent, and a considerable number of astronom-
ical and meteorological instruments figured amongst
t]^ numerous presents received at the \'atican.
After the close of the exhibition the ijuestion
naturall}- suggested itself, \\'hat should His
Holiness do with all these scientific instruments?
Fathers Denza and Lais, who had had charge of
the scientific section, at once proposed that the
collection should be utilised to reconstitute the
\'atican Observatory, and as the project found
immediate fa\-onr with the Pope, who was himself
not only a mathematical prizeman of earlier \-ears,
but a man of high intellectual attainments generalh',
it \\as rapidly pushed forward, with the gratif\ang

result that the newly-reconstructed mstitution was

soon enabled to claim a place among the eighteen that the same careful observer has been for some

science as the observatory acquired additional
telescopes. Four modern obser\atory-domes now
surmount these ancient ramparts in a line, and as
the distance separating the extreme domes is S(.ime-
thing like half a kilometer, the \'atican astronomers
may be said, with Professor Turner, to be living in
space of one dimension only. Nor is the uniqueness
of the situation diminished In' the fact that for a
space of about eighty-fi\-e meters where Leo"s
Cyclopean masonry has \ielded to the ravages of
ten centuries, a slender steel bridge (see Figure 2),
the gift of a wealth\' American, has replaced the
massive wall
between the domes to be maintained.

The largest dome, nearh- nine
diameter (see Figures 2 and 3).
new sixteen-inch visual refractor by
ranks with the similarh' sized
at the Collegio Roinano and at Dr. \'incenzo
Cerulli's private observatorx', Collurania. at Teramo,
as one of the largest telescopes in Ital\- after
the nineteen-inch Merz refractor of the Brera
Obser\ator\' at Milan. It was mounted by
Gautier. of Paris, after the advent, in 1906, of the
l)resent director, Father J. G. Hagen, who left the
observatory of Georgetown, \\'ashington, to assume
the astronomical leadershi[i at the \'atican. His
monumental work, the Atlas StcHiiniiii Wiridhiliiim.*
which was prepared in America and completed at
Rome, undoubtedly marks an epoch in the study of
variable stars, and it is a great satisfaction to know-

thus enabling mter-commumcation

meters m

coyers the

Merz, which

instruments

great mternational oliserx-atories taking part in
Admiral Mouchez's comprehensive plan of photo-
graphing the entire heavens. Under the directorship
of Denza, a zona ViitiLijiui was accordingly com-
menced with the arrival, in 1893, of the Henr\--
Gautier astrographic telescope from Paris (see
Figure 1). This instrument, however, which, like
the similar one at the Paris Observatory, is
mounted on the so-called English system, wai
no longer placed on the old " Tower of the W'inds"
— now given over tn the housing of the archives —
but in a free position some four hundred meters
distant and on the summit of the Vatican hill,
far from all disturbing influences. To ensure its
best performance, moreover, it was mounted on one
of the massive turrets (see Figure 5) forming
part of the ancient fortifications erected in the
ninth century by Leo IV, who, converting the
tribute offered by the Emperor Lothair to
this practical end, thereby sought to put a
stop to the frequent incursions of the Saracen
hordes. Despite the curious anachronism invoKed
in providing a highly specialized instrument of the
nineteenth century with a foundation dating from
the ninth, the experiment proved an unqualified
success, and the remaining towers of the Leonine
wall were one by one pressed into the service of

time past engaged ujion an extensive research into
star-colours. These latter in\-estigations have been
carried out w ith a small Merz refractor of only four
inches aperture, and Father Hagen has already paid
a handsome tribute to the clearness of the Italian
skies in expressing the opinion that the colours of
stars appear more yi\'id at his new post than they
did on the American continent.

The site of the \'atican Obser\-atory might indeed
arouse the en\\- of many a larger and less favourabh-
situated institution, and the writer having, through
the courtes\- of the director, as well as of Dr.
Cerulli (who kindly furnished the introduction + ),
but recently enjoyed the pri\-ilege of visiting
the institution, can bear witness to the natural
advantages of its position, no less than to the
natural charm of its surroundings. Nature, Science,
and Art appear here in the happiest alliance.
A spacious vaulted apartment in the great tower,
now bearing the sixteen-inch refractor, had been
utilized b\- Leo XIII as an audience chamber, and
is decorated in an ingenious manner. The constella-
tions visible from the latitude of Rome are painted,
together with their appropriate figures, upon the
domed ceiling, which thus represents the celestial
\ault, and as the various human figures standing for
(iciuiiii. \'ii\^(). and S(i (in. are most artistically treated.

■ For an able review of this line work, see Joiinial. British Astronuinical Association. Vol. xvii., page 407.
1 I take this opportunity of acknowledging my indebtedness to these gentlemen for the nujterial aid they have afforded me in

collecting the notes for this article.

February, 1911.

KNOWLEDGE.

59

the impression of the whole, which is tlie \\ork of
the well-known painter, Seitz, is an exceedingh-
pleasing one. The constellation Leo. in honour of
the late Pope, is not onl\- shown at its culminating
point, hut its i)rincipal stars are replaced In' minute
electric glow-lamps, so that their effect, when lighted,
is ver_\- charming. Hard by, in the \'atican gardens,
a surprise of a different kind, but also conceived in
honour of Leo XI IE awaits the visitor, in the shape
of a large open-air den containing the two magnifi-
cent lions presented to His Holiness bv the Emperor
Menelik. As in Rome itself, that city where of all
others the centuries ma\' be said to meet, and where
the works of wideK' distant ages unite in strangest

famous grotto of LourdeS; Vs-ith its bubbling si>ring
of healing waters all complet'^ !

Father Hagen. however, has succeeded with
masterly skill in uniting t' ; various outlying
(Ifliartments nf his observator\ into one organic
whole. New instruments have bec-.i purchased, new
measuring appaiMtus introduced fc: the n-_asure-
ment of the asc. graphic plates (one of the chief
tasks of the obser\a*ii--\-), and new work it oa foot;
while the substitution of a spectrohelu -rj.ph, on
Professor Hale's s\-steni, for the existing ;;l'ioto-
heliograph will probably take place in the i-.e£.r
future. With so able an observer at the head c:
affairs, assisted as he is h\ the energetic cooperaaon

FiGL'RI-: 4.
The Dome containin.^' the I'hotoheliograph.

contrast, so in that portion of it represented b\- the
Pope's garden the juxtaposition of incongruities is
not wanting. Mention has already been made of
electricallv-driven oliservator\--domes and steel girder
bridges crowning the mig"ht\' bulwarks of a h\-gone
da}-, but this is not all. Midwa\' between the
observatories themsehes there rises the slender spire
of the chapel surmounting an exact replica of the

FiGi-Ri: .T.
Ill this Dome is the Astrogrnphic Refr.ictor.

of Fathers Lais and Stein, the \'atican Observator\-,
now fulh' reconstructed, and equipped with modern
appliances, has certainly entered upon one of the
brightest periods of its long career. The massive char-
acter of its foundations, the seclusion of its position in
the midst of the \'atican gardens, and the singular
fiurit\' of the Roman sk\' under which it works, all con-
s;)ire to render its obser\'ations of exceptional value.

DRMOXSTRATIOX OF THE PRF.SE\XK OI^ .ST.XRrii IX .A I.KAF.

Er is customarv tn Imld. in connection with the
Annual Meeting of the Association of Public School
Science Masters, an exhibition of scientific apparatus
and books likelv to be of use in science-teaching.
The show is divided into two parts, one consisting
of exhibits h\ members of the .\ssociation, and the
other of displays by opticians, instrument-makers and
scientific publishers. There was an exceedingly fine
exhibition at the January meeting, and the present
writer was particularh' interested in a modification,
devised by Mr, O. H. Latter, of Charterhouse, of
the usual experiment to demonstrate the presence of
starch in a leaf which has been exposed to sunlight.
For those who do not know the details, one may
say that a leaf is exposed to sunlight for some hours,
gathered, boiled in w ater for a few moments, and the
green colouring or chlorophyll, dissolved out by
means of methvlated spirit. In turn the alcohol is
washed out by water, and finally the leaf is placed

in iodine solution, which turns the starch blue.
Although it is possible to get an intenseh- blue colour-
ation of the leaf, especially if a suitable one has been
chosen, and iodine dissolved in a solution of potassium
iodide has been used, as the writer can testify by
experience, Mr. Latter thinks that this method of
showing the leaf when in the iodine solution makes
a considerable demand upon the imagination: for he
describes the colour produced as a dull purple-brown,
that is, a mixture of the colour produced in the
starch with that in the other constituents of the leaf.
His plan is to remove the leaf from the iodine
and place it at otice in benzole. The benzole then
dissolves out the iodine from the cellulose walls of the
cells and from the protoplasmic contents, but does
not break up the blue starch-iodine compound.
Hence the blue colour shows up very plainh' in the
leaf, being no longer masked by the yellow-browns
of the iodine stained cellulose and protoplasm.

NE

S AND \ER\'OUSNESS

DAVID FRASER HARRIS. ^[.D.. B.Sc. (LoxD.)

^Lecturer t>ii l'hy.^i<)h)i>y. I'liii'crsity of lUinmt^haiii.)

iCoiitinucd fruiii pci^^c 22.)

The answer to-day to our question is that we do
know something of the material hasis of nerve
energy, although only a few \ears ago we should
h" , e had to confess complete ignorance, ^^'e helieve
'.; to be related to microscopic granules named after
a German neurologist. Xissl. These granules of
Nissl are known to break up in cells that are
fatigued, luu to be reformed when the cells have
rested, so that we infer they are connected with
the output of energy. In various mental diseases
they are altered, also in alcoholic poisoning : the
brain is never in good health if these granules are not
of normal aspect. It is these granules which contain
a high jiercentage of phosphorus. Long before the\-
were discovered it was known that nerve-matter
[)ossessed much phosphorus, and hence arose the
popular notion that to gain nerve-strength one ought
to eat foods containing much phosphorus — fish and
animals" brains for instance. Now while it ma\- be
good to eat fish and brains, the notion underhing
the practice is based on the fallacy that we
can increase the amount of an\- element in the
tissues provided we eat food containing much
of it. But the fact is we cannot in this wa\- over-
saturate the tissues with any given element : the
tissues can absorb (assimilate) only a certain
quantity of it, corresponding to their particular
chemical affinity for the substance in question. In
conditions of health this affinitv limit cannot be
exceeded, but it is otherwise in cases of patho-
logical deficienc\- of the element in question. For
instance, a healthy man bv taking a great deal of iron
in his diet w ill not cause a greater quantity of it than
normal to be retained by his tissues : but the case of
a person who has not been absorbing enough iron is
quite different. If now capable of absorbing it, he
may, by taking foods rich in iron, bring uji the iron-
content of his tissues to the normal but not bevond
it. The case of phosphorus is similar. If for any
reason the central nervous s\stem has been starved
of phosphorus, then food containing it ma\' be gi\en
with advantage, but the phosphorus-content of the
brain cannot be raised above the normal. Wastiup
diseases of the central nervous system certainh-
involve loss of this element which ought to be
compensated for. The same reasoning applies to
phosi)hatic tonics. They may benefit the l)od\- in

certain wavs. but thev cannot become the means of
increasing the percentage of phosphorus beyond its
normal in the ner\'e-tissues.

We mav now ask ourselves what is it that keeps
up the continual outflow of impulses from the centres
to the peripher\- ? The answer is that this energy is
liberated in the special granules already alluded to
bv the inpouring of afferent impulses constanth'
arriving at the centres of the nervous system.
When one thinks carefully about it one sees that a
vast number of all sorts of impulses must be pouring
into the nervous centres both from all the sense-
organs as well as from the internal organs. Sensory
impressions from the organs of vision, hearing, smell,
taste and from the skin — those of contact, pressure,
heat and cold — and others of a less well defined
nature from internal organs are continually arriving
at the ner\ous s\-stem. Painful impulses are from
time to time also coming in. ^^'e are not, of course,
conscious of a tenth part of all these, but they are
pouring in ne\ertlieless ; some of them even in sleep,
when those from the skin and internal organs are
still entering the ner\ous system. The nervous
svstem is never without some incoming impulses,
and we are powerless to prevent the entrance of the
\ast majoritx- of them. Just as the hum or roar of
the traffic of a great city pours into the room
when the window is opened, so do the afferent
neural impulses pour into the brain and spinal cord.
The general tendency for these impulses is to cause
the nerve-centres to "discharge : that all the centres
are not simultaneously discharged is due to a large
number of cooperant conditions. Some impulses
ma\- be too feeble to arouse the first centre
encountered, as when the fl\- is not felt until it has
stung vou : but a series of such too feeble impulses
mav, bv being summated, effect what no one of the
series is able to do. Or. again, two impulses may
meet and interfere with each other in such a way
that no action is aroused, just as when two sound-
waves meet in a particular fashion and give rise
to silence, or two colour-waves to blackness. This
last case is one of "inhibition by interference" of
neural currents.

There is no doubt that the -general incoming
neural " hum " goes to produce those outflowing
currents which maiiitaui the unconscious general

00

February, 1911.

KNOWLEDGE.

61

tissue-tone. In proportion as we cut off the
multitude of incoming impulses so tone vanishes ; as,
for instance, in sleep, in which no impulses are coming
in from the higher sense-organs, and therefore the
centres for tone to a large extent are unstimulated.

Keeping animals in the dark and in silence lowers
their tone : cows kept in dark byres secrete poorer milk
than those in well lighted ones. This is due to the
depressed chemical tone of the cells of the mammar\-
gland. It has beeii experimentally proved that if the
afferent nerves from a limb are cut, the muscles of
the limb suffer diminution of tone. It is evident, there-
fore, that the afferent nerves and the efferent nerves
are functionalK" verv closely related through the
intermediation of their common centre. The entire
nerve-path from the periphery, up the afferent nerve
through the centre and down the efferent nerve is
known as the " reflex nerve-arc." A vast number of
the functional units of the central nervous s\'stem
can be looked upon as reflex or " sensori-motor "
nerve-arcs. These arcs are continualh' recei\ing
impulses one wav, and sending them out the other
wav. that is transmitting them in one fixed direction
onh'. The impulses which go out are not identical
w ith those that come in : in many cases, although
thev come in continuously, thevgo out intermittenth-
bv special rhvthms of their own.

Now the intensitv of the response given by a
centre depends upon two things — first the intensitx'
of the incoming impulse, and secondK' its own
condition of being affected b\' the stimulus easily
or the reverse ( Affectabilit\'). This a[)plies to all
centres, whether those in the cord unrelated to
consciousness, or those in the brain related to
perceptions, emotions, ideas and the will. Now-
one form of ner\-ousness is that associated with an
abnormalh' violent response to a stimulus. This
form of nervousness is that of the " nervous tempera-
ment " as opposed to the j)hlegmatic, for there is
more than a grain of truth in the old classification
into h-mphatic or phlegmatic, nervous, sanguine and
melancholic temperaments. The nervous tempera-
ment has in recent times mereh' been rechristened
" neurotic."" A neurotic person is one whose nerve-
centres are, as compared with those of the majority
of people, undul\- aflectable. This condition of
undue affectabilit\' manifests itself in nuin\' \er\'
different ways. If a hundred people are in a hall
and a door bangs loudlw three of them iiia\' jump
up from their seats while the other ninety-seven
mereh- turn their heads in the direction of the
sound : tlie three would be for the compan\- in
question the representatives of the neurotic con-
stitution. The physical intensity of the stimulus
was presumably the same for the whole hundred,
but it produced a greater effect on three of them
because their nerve-centres were in a state of
excitability greater than the average for the particular
company in the room at the time. Again let us
suppose a hundred people come into a place where
there is a large bowl of powerfullv perfumed roses :
ninet}-seven appear indifferent and settle down to

various occupations: one is visibly delighted with the
odour: 2 second says, "That is a smell I detest,"
while tl J third gets an attack of asthma. The last
three are " nervous '" as regards the neural average of
the assemblv . Their nervous systems are unduly
affected by tli perfume of rose; • the form it
takes in one distinct aesthetic pleasure, in a
second well-mark. .1 aesthetic pain, in z. third it gives
rise to a motor effect, a spasm of the muscles of the
lironchial tubes. This last is known as ar. s.-^itack of
asthma ; it belongs to a class of conditions called
neuroses. Neurotic people exhibit neuroses. A
neurosis is an excited or excitable state 01 some
centre or centres of the nervous system expressing
itself in an outflow of nerve-energ\- into such channels
as injurioush' aftect certain organs or tissues.
Nervous attacks or " attacks of nerves " may be
taken as the popular s\'nonyms for neuroses — fits
of trembling, limbs shaking, "'the ([uivering like
an as[)en leaf "' of the novelette, palpitation and
other visible effects of fear on the approach of an
ordeal ("stage-fright,"" examination fright), blushing,
blanching, perspiring, ililataticm of the pupil, and in
some cases even vomiting, all well-known results of
stimulation of lower centres acted on by impulses de-
scending from higher ones. Popularly the '" nervous""
person is the one who blushes, pales or perspires too
easiK'. whose centres for these expressions of
emotion are abnormalh' aftectable and are set in
motion hv conditions which would ha\'e little or no
eft'ect on a person perfectly normal as regards the
nervous system, a person with what is called a
■■ well-balanced nervous system."" What, however,
is the cause of the abnormal aft'ectability of the
centres in a nervous person it would be difficult to
sa\'. In many cases it is probably due to malnu-
trition of the centres. Nerve substance is chemically
only a ver\- complicated form of fat, and fat people
are almost ne\'er neurotic. We must not jump to
the conclusion that because a person is fat his
nerve-centres are of necessity well nourished, though
thev usualh- are. There are various kinds of obesity,
some not indicating good nourishment ; but as a
rule it is lean people who are nervous. This is, of
course, what Shakespeare alludes to when he makes
Caesar say —

" Let me have men about me that are fat ;
Sleek-headed men and such as sleep o' nights :
Yond' Cassius has a lean and hungry look :
He thinks too much : such men are dangerous."

Of course we must distinguish between the thin,
pale, neurotic person, and the thin. " wiry," fit
person whose nerve-centres may indeed be aff'ectable
without being abnormalh" or weakly affectable. For
there is the healthy, robust nervous system with
plenty of nerve-energy able to be discharged, and
there" is the weakly, excitable system with little
energy alwa\-s tending to leak away. The two
conditions are quite different. The ease of response
to a stimulus is one thing, the amount of energy
liberated by a stimulus quite another thing. The
same amount of pull will fire oft' a pop-gun

62

KNOWLEDGE.

February, 1911.

and a " twelve inch,"' but ths amounts of energy
liberated b-- these equally exc'table mechanisms are
immeasurably different. I'-'i oiher words, there is
a high affectability couple:,. ■,', iai the output of much
nerve-energy, and there 's a ii.^h affectability coupled
with the output of -ircie : this latter constitutes
" irritable weakness " {" \. aakness to be wroth with
weakness"): it is ;; ihat is the basis of neuroses,
of nervousness. .■ : : brain-centres related to
consciousness ca : co exert on the lower centres
a restraint thai; :. learnedK' called " inhibition."
Inhiliition or r:: . aint by the higlier on the lower
plays a 1:1^,0 .t in the acti\-ities of the central
nervous . st-.aii. Persons neuralh" robust ha\'e
inhibit- ;; v.ell developed. ner\ous people have it
poorl\ aeveloped. Inhibition is of two kinds, that
unccasciously and that consciously exerted. The
for;^,er is the more mechanical kind of restraint
w .iich any one centre exerts on any one lower down
in the neural scale. Thus it is that when the head
is cut off. the posterior part of a worm wriggles more
actively than the head end : it has lost the automatic
restraint of the head end. The legs of a decapitated
crayfish "work" much more ra[>idl\- than in the
intact animal. ^^'e may oursehes emplo\- this
form of mechanical inhiliition in restraining, for
instance, an awkward sneeze liy hrmh' pressing
on the upper lip. The otherwise uncontrollable
tendenc}- to sneeze is abolished b\ the impulses
from the skin of the lip ; the_\- act here as inhibitor\-.
That it is only inhibition of the tendency and not
removal of it is interestingly brought out sometimes
by the fact that after a certain inter\-al of time the
sneeze may be produced in v.hat would have been all
its original intensity. The stillness of an attentive
audience is a case of unconscious inhilntion : the
subsequent coughing and restlessness is e\idence
that it was only inhibition and not abolition that was
at work. But by means of the w ill \\ e can consciousK-
inhibit or restrain. What we call "education" is
very largel\- the cultivating of latent powers of this
order ; the psychological difference between a
Hottentot and an ambassador is the high de\-elopment
of the powers of inhibition ac(iuired by the latter.
Training in children and animals means their
acquiring inhibitory powers : a performing tiger has
to restrain many instincts and tendencies before it
can be convenientl}- exhibited in public. Now some
forms of nervousness are the result of loss of
inhibition resulting in the expression of violent
emotions and violent responses of all sorts. The
strong man is not the violent man : the strong man
is the man who restrains the exhibitions of his
strength, who strongly controls strong emotions for
his own good and that of the community. The
neurotic person, not jjossessing the necessar\- [lower
of inhibition, does not do this. Better is " he that
ruleth his spirit than he that taketh a city " : that
\vas written long ago, lint the nervous system
was the same then as now ; in modern language
it is inhibition that is alluded to. Nervousness may,
then, in one form be a condition of diminished

restraint. We talk about a nervous dog that barks
apprehensively at every little incident, of a nervous
horse that jibs and shies at all sorts of harmless
objects : inhibition is that in which these animals
are deficient. It is. then, clear that the deN-el(.)pment
of inhibition is the essence of foundation of character :
a person with little inhibition may do all sorts of wild
things, succumb to all sorts of temptations: conscious
inhibition is the physiological name for self-control.
Lack of inlnbition is one of the elements in neur-
asthenia, that low nervous state to which reference
has already been made. H\steria, again, is a form
of nervousness; it is a morbid state of the central
nervous s\-stem. and has been described as the acting
or imitating of some other disease. " A fit of
h\sterics " is really a violent emotional display due
to diminished inhibition. In true h\'steria all sorts
of morbid conditions are imitated. — fainting, par-
alyses of various kinds, and so on. Some hysterical
people cannot walk, cannot talk, cannot eat, cannot
get out of bed, and so forth. Hysteria is a form of
" nervousness." if " nervousness " means anything
unusual in the nervous system, which is apparently
all that in certain cases it does mean. The term as
popularlv used covers a large number of very
different conditions, liy a nerv(.)us child is meant
sometimes a shv child, one not sufficiently self-
reliant. v\h() shrinks from strangers, and is not soon
at home amid new surroundings. It may only mean
a child that does not like to be left alone in the dark.

A verv well marked form of nervousness is the
'■ fear " of various conditions, such as fear of looking
over heights, fear of open spaces, fear of enclosed
spaces, fear of the presence of crowds, and so on
through all the varit)us " phobias." as they are called,
many of which are ludicrous to those incapable of
experiencing them. Allied to hysterias and phobias
are certain harmless obsessions which, however, lead
right on to the illusions, delusions, and hallucinations
of typical mania.

In connection v\ith nervousness we have the
factor of siiihlciiiicss to reckon with. Something
happening without v\arning will ;//merve a man or
animal which it v\ould not do had the occurrence
been foretold or developed gradually. Just as a
sudden knock will break a glass, which the same
pressure cautiously applied would not. so a sudden
mental blow will injuriouslv aftect the nervous
system in a v\av it vsould not have done had it fallen
more graduallv. ISoth non-living and living molecules
resent sudden changes of state; both can endure
strains if gradually apjilied which would not be
withstood if applied without warning. Especially
should the affectable and plastic nervous systems of
children be protected from sudden impacts. Per-
manent damage may be done them by " taking them
by surprise,"' "giving them frights," suddenly showing
them " horrors " and so forth. The nervous system
will "endure"" (almost) "all things" provided they are
presented to it in graded order : it may be trained
by degrees to suffer conditions which if suddenly
developed vvouM liave~ overwhelmed it altogether

SOME MAORI CUSTOMS AND BELIErS.

l\x K. W. RKID

t^XcK- Zealand).

Though the Maoris of New Zealand are rapidlv
adopting the civilisation of the whites, the}' seem
reluctant to part with man\- of the customs and
beliefs of their forefathers. The settlement of the
country by the British and the introduction of
British law rendered the old mode of life impossible.
Most of those peculiar observances witnessed h\
early navigators and others, wliich were opposed to
English ideas, had perforce to cease. But long-
established social customs, when not ver\- harmful,
albeit not always strictly legal, were never, and are
not now, subject to interference from the authorities.
Keen recollections of earlv da\s in New Zealand,
while police, courts, and judges were \-et unknown,
abide to-da\- in the memories of not a few grizzled
and tattooed veterans. Thus the writer's friend,
Hori (the distinguishing appellation had better be
here omitted !) a Ba}- of Plenty chief, is able to
confide to those he deems worth\- of being entrusted
with the interesting autobiographic information,
that, when a voung man, he. on several important
occasions, did partake of " kai tangata." An
unsuspecting enquirer, learning that " kai " is ^hlori
for " food," and that " tangata " is the equivalent to
" man," might hastily conclude that "kai tangata"
represented an article of diet neither uncommon nor
alarming. Hori, however, could explain that, used
by him, the phrase meant, not " the food of man,"
but "man. the food." and that, in ancient Maoriland.
was a difference indeed.

Polygam\% never a common practice among
Maoris, and generalh' confined to men of rank, is now
almost extinct. An official report of recent date
states that there are on!\- three or four cases of
Maoris having more wives than one, and that these
are among the Ruatahuna natives on the Bay of
Plenty. Rua. who lives in the Urewera countrv,
and claims to possess certain supernatural powers,
six months ago had eight wives. \'er}- likely
he has more now. He is the most married
inhabitant of New Zealand ; the Maori next to him
possesses but the relativeh" modest number of three.
When a dweller in pah or kainga (village) dies, the
event is followed by a " tangi " or weeping. If a
chief, or person of importance, his '" tangi " is attended
by hundreds of Maoris ; relations and friends are
there, and, in addition, nearlv all the natives of the

district. The proceedings are not infrequently pro-
longed over many days, and become a medley of
formal weeping, of feasting and of merriment.
Immense sums are often expended on tangis : the
cost mav var\- from £50 to £500, according to the
rank of the deceased and the financial capabilities,
or inclinations, of his relatives. Among the very
old, and more curious customs which survive is
that of " tapu.'" By that wonderful law shrines,
burial places, chiefs, and all things a chief handled,
were, in former davs, believed to be rendered sacred.
Whatever \\as "tapu" must not be profaned by the
touch of common mortals : in olden days death by
execution followed an act of desecration. At the
present time, even among educated Maoris, a more
or less shadowy belief lingers that "tapu" is not yet
bereft of its awful potency. For example, the
deca\-ing wood of an empty, unclaimed whare, or
house, would not be interfered with by a strange
Maori. The whare might be " tapu," and its
desecration might bring disease and death.

A striking illustration of the present-day belief in
" tapu " on the part of the Maoris is provided by
the settlement, or village, of Maungakawa, near
Cambridge, in the North Island, \\hich place was
once the home of Tawhiao, King of the Maoris.
Gre\-, bleached whares are scattered about on the
hilltop, grass and wild-flowers grow close to door
and w indow . Roofs are falling in, gaps are appear-
ing in the raupo walls. Within the buildings lie
household goods, articles of clothing, mats : every-
thing remains as it was when, sixteen years ago, the
owners were called upon to go forth and seek a home
elsewhere. For Tawhiao had died and the tohungas,
or priests, had laid tapu on the king's council hall
and on his house, on the dwellings of the people,
and on all the lands of Maungakawa. Since that
da\-, whatever curiosity irreverent pakehas (whites)
ma\- have exhibited, it is safe to say that few, or no,
Maoris have entered within the now sacred circle of
the one-time royal settlement. The late king's
whare stands apart from the other houses, and is
rendered conspicuous by its large size and the wealth
of Maori carving with which it is ornamented.
Rumour states that Tawhiao's body lies beneath the
floor of the whare. .\nother, and a more probable,
storv is that, after its interment with Christian rites

bi

64

KNOWLEDGE.

February, 1911.

within the ix.uitly churchyard, the bod>'. in accor-
dance with .Maori custom, v.ii exhumed. Following
the practice of their anc.:'::'; the Maoris \\ould
remove the flesh from K-^--^t rangatira's bones

with pieces of sharp - 'j3i:.;--n, and the Inmes would
be painted dark ree ried together with ropes of
grass, and deposits ; : : .i secret cave somewhere
among the neighl-r ;i.' : iiountains.

At the large a/. _ ■:\'^-:: principal nati\e settlement nf
Mataatua, in tV i I'-iwera, is a much car\-ed temjile.
or praying her,:; .hich was built by the Hauhaus
to the men-' :;;■ - t their great warrior, priest, and
prophet, Te I u. Until recentl\- it was altogether
tapu : ii : .. ::. some reason not clearh- understood
by tl; v.riter, tapu seems to ha\e been partially
removed. But \isitors. liefore entering, pakehas not
excoiUed, are compelled to lea\-e outside such
mi; .dane articles as purses, tobacco, knives and
n aches. The presence of food within the building
^^ould still be considered a desecration. This temple,
or wharetapu. is considered by authorities to be
probably the most interesting sj)ecimen of Maori
decorative architecture in New Zealand. Surmount-
ing the entrance to the temple, which is alwa\s
spoken of by the Maoris as " Te Whai-a-te-Motu.""
is a carved head or " teko-teko," dark red in colour,
its large, shell-made eyes aglitter. This represents
the warrior-chief. Te Unu-ariki, who. more than a
hundred years ago. was the most prominent bra\-e in
Tuhoeland. Below the " teko-teko," carved and
painted, appears a monster, half-dog, half-crocodile.
This effigy is that of Tangaroa, the enchanted dog
of Taneatua, a chief who, six hundred vears ago,
reached the Ba}- of Plent\- in the famous canoe.
Mataatua. The dog, according to Maori belief, was
left by Taneatua at a small lake among the Urewera
mountains, where it can still be seen as a " tipua,"
or demon. Within the temple are inanv carved
images of entirely fabulous creatures, and numerous
extremely grotesque statues of the tribes' ancestral
heroes.

Ancient Egypt is recalled by a visit to an old,
well-preserved, highly-decorated Maori settlement.
In the painted and sculptured scenes depicted on
Egyptian tombs the kings stand out boldlv in the
foreground, and their tall figures tower abo\-e all
else. So it is in Maoriland. The greatness of the
chief is represented by his colossal size. Rudeh-
drawn and glaringly coloured canoes are favourite
subjects with the Maori artist. Every canoe must
have its chief, and he is shown usualh- four times
taller than the others. Egyptian-like ideas, as well
as Grecian, still prevail as to the close connection
between gods and men, as between men and trees,
and certain lowly animals. Tane, the god of the
forests, yearly sheds his blood when the rata blooms
tinge the sombre woods and tree-covered hills with
glowing crimson. For misdeeds, and b\- the evil
agency of tohungas. men and women have been
transformed into rocks, into trees, and into
lizards. The Maoris claim to have descended from
different objects, animate and inanimate. HiL;h-

born individuals, that is chiefs or rangatiras, favour
the genealogy that gives them the tuatara lizards for
ancestors. And that belief is b\' no means extinct
at the present time. Not man}- months ago. in the
New Zealand Native Land Court, a Maori title to
lands was in question. The appellant, who founded
his hereditary claim cm remote anticjuitx-. proceeded
to recite his list of distinguished forefathers. There
was Te So-and-So, the original holder of the land,
whose son was Te So-and-So. whose son was Te

So-and-So "Hcjld on." called the judge. as the list

was being rolled out —he knew the Maori wavs —
"These names you have been giving us. are they the
names of men?" "Oh no," replied the Maori, "not
come to men \"et. The names I give \'ou are of
tuataras." "I thought so." responded the judge,
" better ski[) the lizards and come to the men."

" Muru" IS another Maori law descended from
remote antiquity. It means an act of re\-enge. or
of justice, carried i>ut b\- those \\ he) deem them-
selves wronged, against the wrongdoer, real or
imaginary. A man or woman commits what is
considered an offence against an individual, a family,
or a tribe, ^\hereu^)on all a\ailable members of that
tribe, who iiia\' be joined hx friends, swoop down
upon the offender, and carry off all his or her
possessions : everything is taken that can be trans-
ported or is capable of walking. A frequent cause
of muru was. and is, domestic infelicity. That the
muru-ing part\' was frequently of considerable
dimensions is seen trdiii its name — taiia muru, which
signifies "a hostile, plundering expedition." A fev\-
months ago. on the b!ay of I'lenty. the present writer
witnessed a jjrocess of muru-ing. A young man,
recenth' married and well off, as the average Maori
would consider, disappeared, and with him the
unmarried daughter of a neighbour. The delinquent
left behind him, not ever\'thing. l)Ut sufficient to
satisfy the inevitable taua muru. Had he removed
all his propert\' the friends of his discarded wife
\\ould have been justified — in their own eyes — in
raiding his relati\es. Two da\'S after the elopement
the taua muru arri\'ed at the home which was about
to be broken uj). The forsaken wife was there, by
no means broken-hearted. Indeed it was a nois\',
jubilant. jo\ial company of marauders. The greater
piart of a long morning was occupied in collecting the
plunder — naiueh'. bags of maize, quantities of
kumeras (sweet potatoesi. rewi (potatoes), and corn;
horses, dogs, pigs and poultry, household furniture
and utensils. It was a happy procession which
wended its way towards the west that evening ;
eyer\- member of the company, from the oldest to
the youngest, had secured a more or less \aluable
souvenir of the day's interesting proceedings. The
writer has been informed of a remarkable cause of
muru-ing which came to light two years ago, also on
the Ba\- of Plenty. A young child, for health
reasons, was brought from Tuhoeland to be nursed
b\- relatives on the coast. The child died, and its
father and his friends unflinchingly harried the
liospi table ct)ast- folks."

THE FACE OF THE SKY FOR FEBRUARY.

Bv W. SHACKLETOX. F.R.A.S.. V.R.C.S.

The Sun. — On the 1st the Sun rises at 7.42 and sets at 4.46;
on the 2Sth he rises at 6.52 and sets at 5.35. The equation
of time is nearly 14 minutes throughout the month, the Sun
being later than the clock ; this makes the afternoons longer
than the mornings. Sunspots may occasionally be observed,
though they are not very numerous. The positions of the
Sun's axis, centre of disc, and holiographic longitude are given
below : —

Date.

Axis
from ;

inclined
V. point.

Centre of Disc

S. of
Sun's Eijuator.

Ileliographic

Longitude of

Centre of Disc.

Ian. 51 -.

i ""

40' W

6° I'

259° 28'

Feb. 5 ..

13"

4r\v

6° 20'

19.!° 38'

,, lo ..

15^

36' w

6° 38'

127^ 48'

., IS ..

I?"

22' VV

6° 52'

61" 58'

., 20 ..

IS"

59' ^\'

f 2'

356° 7'

,, 2S ..

20-

29'\V

7" 10'

290"" 1 6'

Mai. 2

21"

4S'\V

7 14'

224° 24'

,, 7 ■■

1 ~^

5S'\V

■^' '5'

i5«° 32'

Towards the end of February and early March the Zodiacal
Light should be looked for in the West, ijiiiiiediately after
Sunset.

The Moon : —

Date. Phases.

11. .M.

Feb. 6 . ,

:; 2^ :

Mar. I .

•' 7 -

jj First Quarter

0 Full Moon

Last Quarter ...
# New Moon
'^ First Quarter -

3 2.S p.m.

10 38 a.m.
3 44 a.m.
0 31 a.ni.

11 2 p.m.

Feb. 9 ...

., 21 ...

.M.ir. 6 ...

Perigee

Apogee

Perigee ..

4 54 P '"■
4 30 P-i"-
4 3° P-iii-

OccULT.\TlONS. — The following are the principal occulta-
tions visible in this country : —

D.ile.

.Star's
Name

Disappearance.

Reappearance.

Mean

Angle
from N.

Mean

.•\iigle_
from N.

IS

Time.

point.
E.

Time.

point.

Feb. 7

A' Tauri

4-5

p.m.

5.26

8°

p.m.

6.4

104°

.. 1 1

\ Cancri

59

5-50

102°

6.SS

272"

" 13

42 Leoiiis

6- 1

8.57

103°

10.5

306"

.. 15

I) \ iiginis

5 ' -

8.24
.1.111.

89"

9-17

a.m.

327"

,, 21

S .Sciirpii

25

2-4

39°

2.20

14-

,, 21

B-'-VC. 5335 ■

5' 7

5 47
1..111.

'31'

7-5

269^'

Mar. 6

A^ T.iuii

4-5

H..57

71"

0 47

270"

THE PLANETS.

Mercury

—

Date.

Right Ascension.

Declination.

Feb. I ...
,, II ...

2 1
Mar. 3 ..

ll. 111.

19 to

20 0
20 59
22 2

.S 21- 26'

21 7'
18 48'

S 14" iS'

Mercury is a mt ..ing star throughout the :nonth, rising in
the S.E. by E. at about 5.30 a.m. The planet is at greatest
Westerly elongation g_ 25" 17' on Febru;:ry 2nd; the
elongation is moderately favourable and about iJ:": date one
has the best chance of seeiii:^ this elusive planet, il^ugb it
will be necessary to observe before 7 a.m.

Venus: —

Date.

Right Ascension.

Declination.

Feb. I ..
., II

., 21

Mar. 3 ..

ll. m.

22 I

22 48

23 34
0 19

S 13" 46'

9" 11'

S 4° It'

N i' 0'

Venus is ,tn e\ening star in Virgo, setting about two hours
after the Sun towards the end of the month, and thus
obser\able for a short time in the West, immediately after
Sunset. In the telescope the planet appears nearly at "full,"
O-q? of the disc being illuminated, with an apparent diameter
of 10".

M.-\RS :

D.ite.

Right Ascension.

Declination.

Feb. t ...
,, II ...

., 21 .
Mar. 3 ...

h. m.
18 2

iS 33
■9 5
.9 37

S 23'-' 40'
23" 44'
23'-' 15'

S 22"' 22'

Mars is visible in the mornings, rising about 5.15 a.m. near
the middle of February. The planet is situated in Sagittarius,
but is rather an inconspicuous object and ill-suited for
observing through the telescope, the apparent diameter of the
disc being less than 5".

Jui'lTER : —

Date.

Right Ascension.

Declination.

Feb. I .
II ...

,, 21 ...

Mar. 3 ...

ll. 111.

14 45
14 48
14 50
14 50

S 14° 42'
14° 53'
14° 5S'

S 14° s«'

Jupiter rises in the E.S.E. before midni.ght at the end of the
month ; on the 1st February he rises at 1.20 a.m., and on the
1st March at 11.35 p.m. The planet, with his bright moons,
dark equatorial belts and spots, is an interesting object even in
small telescopes. He is in quadrature on the 3rd February,
and at the stationary point on the 1st March. The equatorial
diameter of the planet is JS", whilst the polar diameter is 2"-5
smaller. This polar fl.attening is readily observed in telescopes
powerful enough to see the belts, but the satellites may be
seen in small telescopes, such as deer-stalkers of about li
inches aperture, or even in a good pair of prismatic binoculars
magnifying eight times. The Moon appears near the planet
on the 19th.

65

66

KNOWLEDGE.

Febru.\ry, 1911.

Saturn :-

Date.

- Right Ascensi-.n.

Declinalion.

Feb. I ...

., i6 ...

Mar. 3 ..

h. n^.

I .—

'2. I

.: 6

N 9'^ 26'

9" 50'
.\ 10" 20'

Saturn is gettir :;: r- to the West, but is observable
throughout the mcr.ch l\i 10 p.m.

The planet is a ^c~' icuous object in the South-West portion
of the sky. and a" ■ .s in Pisces about ten de.^'rees South of
a Arietis. Obse:-. :j in the telescope, the ring appears open
fairly wide, =iriCC e are looking on the Southern surface at an
angle of 1. ". "The apparent diameters of the outer major and
minor a:..-; of the ring are 40" and 12" respectively, whilst the
diamel,-- of the ball is 16". In the telescope, in addition to the
ring, t!..' belts on the planet's disc — although not so conspicuous
as ti.ose on Jupiter — may easily be discerned. The Moon
aprars near the planet on the 5th.

L'kaxus:-

-

Daie.

Right

-Ascension.

Declinatii

in.

Feb. I .
Mar. I ...

h.
19
19

111. s.

.i3 20
59 36

S 21^- 24'

S 21- -■

3

13"

Uranus is a morning star, rising about 6.30 a.m. near the
middle of the month, and for all practical purposes is
unobservable.

Neptune : —

Date.

Right .Ascension.

Declination.

Feb- I ...
Mar. I ..

h. m. s.
7 24 2S
7 -' 50

\ 2." 25' i"

.\ 21- 2S' 45-

Neptune is situated in Gemini, about three-and-a-half
degrees South-East of the star 5 Geminorurn. The planet is
on the meridian about 9.40 p.m. near the middle of the month,
and is practically above the horizon the whole night through-
out the month. He is difficult to detect exxept in large
telescopes, but he may be identified in small telescopes by his
relative motion if successi\e observations are made some few
days apart.

Meteor Showers: —

Date.

Radiant.

Near to

Characlejistics

K.A.

1 Ire.

Feb. s-io

., ' 15
20

h. 111.

5 "
■5 44
12 4

+ 41

+ ir
+ 34"

J) -Vurigae
a Serpcnti.s
Cor Caroli

Slow ; bright.
Swift ; streaks
Swift : bright.

Minimaof Algol occur on the 19th at 8.38 p.m.. and on the
22nd at 5.27 p.m. The period is 2'* 20"" 49"" from which data
other minima ni.H\' he calculated.

Mira lo Cetil is due at miniiniun on February 26th. its
magnitude being about 8-5.

Double Stars. — Castor, separation 5'-5, mags. 2-7, 3-7.
Excellent object for small telescopes. The bri,ghtest pair to
be observed in this country ; can always be relied upon as a
good show object.

K Geminonim, separation 6"-j, mags. 4. 8-5 ; very pretty
double.

fCancri, separation 0"'9, 5"-2, mags. 5-5, 6-5, 7-5; with
small telescopes the wider component is readily seen.

" Draconis, separation 61"-7, mags. 4-6, 4-6 ; a pretty and
easy double; can be separated by observing with a pair of
opera glasses.

Clusters. — M 44, the Praesepe in Cancer, visible to the
naked eye as a nebulous patch, best seen and easily resolvable
with a pair of opera or field glasses. On accoimt of the
scattered nature of the group the cluster effect is lost when
observed with a telescope unless very low powers be employed.
Situated about midway, and a little to the West of, the line
joining a and <> Cancri.

THE .AS.SOCI.ATI()N Ol- PUBLIC .SCIIooL .SCIHX'CE M.A.STER.S

.At a general meeting held at the Limdoii Day Training
College, on January 11th, Sir Kay Lankester, F.K.S., the
President of the Association of Public School Science Masters,
gave an address upon "' Compulsory Science versus Compul-
sory Greek." So far as his own experience went, he condemned
public schools. At the one which he himself attended, he
maintamed that he learnt nothing, though he was at the top of
his various forms, and finished as the head boy. He thought
that all the ptiblic schools should be day schools, that no
master should be allowed to keep a boarding-house, being paid
sufficiently well to make it umiecessary. and that only
the very ablest teachers should be employed. He urged
that the boy should have home surroundings, plenty of time
to himself, and a place in which he could work undisturbed.
Sir Kay Lankester brought many arguments to bear against
compulsory Greek, and among the strongest of these were the
following: — That althotigh Latin had in times gone by been a
necessity to the educated man. and was reijuired if the scientific
progress of the day was to be followed, the intention of learning
Greek was to be able to read the works of the Greek authors
in their own tongue. Many of the translations which exist
render this unnecessary, and as an answer to the contention
that Greek should be studied because classical men appreciated
the Greek ideals, a translation was given of Aristotle's descrip-

tion of what constituted a good education. This coincided
almost exactly with what a scientific man would lay down to-day.

In conclusion, a detailed scheme of work beginning with
what Sir Kay Lankester called Equipment Studies, was laid
down, and the way in which it could be carried out with efficiency
was outlined. .-Vmong the Equipment Studies were these, in
the order in which they were given: — English language, Latin,
French. German, and .Arithmetic.

.After the Presidential address, Mr. .A. V'assall (Harrow)
dealt with the education of a medical student. He pointed
out some common misunderstandings with regard to the
powers and functions of the General Medical Council, and
thought that if there was a movement in favour of one central
qualifying body, the latter would probably be the Council in
question. "The .Association," he said, "must watch that this
does not happen without the Head-masters' Conference being
aware of it, otherwise, when it was too late, public schools
would find themselves biu'dened with yet one more syllabus
forced upon them as necessary for a good general education."

(Jn the second da\- of the meeting, among the subjects down
for discussion were the teaching of English in connection
with science lessons, introduced by Mr. W. D. Eggar (Eton),
and the use of the wave theory and of rays in teaching light.

NOTES.

ASTRONOMY.

By F. A. Bellamy. M.A.. F.K.A.S.

THE ASTRONOMICAL SOCIETY OF BAKCl^LONA.
— The first annual meeting of this Society was held on the
8th December last, when, in accordance with the rules, the
new president and executive council were elected. Interesting
addresses were delivered by the retiring President on the
progress of astronomical science during the year 1910, and by
the Secretary on the development of the Society since its
foundation. The inaugural meeting of the Society was held
on the 30th January, 1910, at the University of Barcelona, as
a result of the laboin's of Don Salvador Kaurich, who had been
carrying out valuable educational work in the city by means of
popular articles on astronomical and allied subjects, contributed
to the columns of Las Noticias. a well-Unown Barcelona
journal. There were present at the inaugural meeting ninety
persons from all branches of Society, including several
professors of science from neighbouring colleges. Dr. Esteban
Terradas, Professor of Science in the University of Barcelona,
was elected first President, and a strong executive council was
formed. In April, King Alphonso became a life member, and
was elected Honorary President. In July, the first number of
the monthly Bulletin was published, and this is nowe.xchanged
with all the leading societies and observatories. In the
following month a prize medal was coined from the designs of
Don Dionysius Kenart. At the present time the membership
numbers two hnndred-and-thirty, and as a result of the first
year's work the Society finds itself with a bank balance of ;^80,
after paying all expenses. In the future it is intended to
devote the accumulated funds of the Society to the erection
and ecjuipment of an observatory, where members may meet
regularly, in a social way. for practical observation and the
informal discussion of questions of astronomical interest. In
the meantime, arrangements have been made with those
members possessing private observatories to allow other
members access thereto on specified occasions.

During the year eight lectures on astronomical subjects
have been delivered in the Grand Saloon of the University of
Barcelona, and numerous addresses on a smaller scale were
given on practical spectroscopy and general astronomy in the
private observatories of certain members.

The following is a list of the officers of the Society for the
year 1911 : —

President: Professor Eduardo Fontsere, D.Sc, Chief of

the Time Service of Barcelona.
Vice-Presidents: Professor Luis Canalda :ind Don

Ferdinand Tallada.
Secretary : Don Salvador Kaurich.
Vice-Secretary : Don A. Pulve.
Treasurer: Professor M. Font y Torne, M.D.
Other Members of the Council : Professor Ignacio
Tarazona, Professor of Astronomy in the Univer-
sity of Valencia; Dr. Enrique Calvet ; Don Jose
Subiranas, and Don Juan Mercadal.

The address of the Secretary is Diagonal, 462, Barcelona,
where all communications should be addressed. The Society
is entering upon its second year of acti\ity with bright
prospects, and is very successfully cultivating a taste for
astronomical study among all classes in Spain.

WlLLL\M PORTHOUSE.

PRELIMINARY GENERAL CATALOGUE ()F 61,SS
STARS. — The publication of this catalogue is the most
important piece of computational work of its kind since the
British Association Catalogue of 8377 Stars was compiled and
published under the direction of F. Baily, about sixty years
ago. Both these works differ from most other star catalogues in
that they are not composed of observations made with one
instrument or at one observatory, but the observations are

collected from the best star-catalogues and records mostl\-
already published at various institutions.

The main principle pervading this work of Professor Boss
is to determine accurate positions for a definite epoch, 1900'0,
— we heartily welcome the adoption in meridian catalogues of
such very convenient epochs as 1900, 1925, 1950, and so on,
rather than the usual plan of taking the mean epoch of the
observations, so any odd year may result, — of all stars observed
that indicate a proper motion of 10" a century, together
with a number of other stars of less motion included for
various reasons: the computation of the motions of all these
stars became the primary aim. Compiling these results in
catalogue form was considered the best way of exhibiting
them.

The stars included in these 6188 are chiefly stars visible
without a telescope, therefore of the sixth magnitude and
brighter; there are 4030 of these, 1919 north stars, and 2111
south stars; of the 2158 remaining, all fainter than the sixth
magnitude, most of them are stars observed by James Bradley
about one hundred and fifty years ago.

A preliminary' piece of work of fundament^d importance
was the preparation and publication of a Catalogue of 627
Principal Standard Stars. In that were described the methods
employed, and upon those star places the present catalogue of
61SS stars was based. During the progress of the work it
became manifest that a great extension of the scope of the
work upon a '"general catalogue" was desirable. Certain
materials for a catalogue of 25000 stars, to about the seventh
magnitude, were available ; but to include all these additional
stars would require re-observation of a great number ; besides,
the increased time and expense required would be very great.
The Carnegie Institution of Washington having agreed to
provide the money for this greater proposal. Professor Boss
decided to complete and publish the smaller work to the sixth
magnitude, much on the lines as planned, depending upon
other observatories' work, and to treat the greater catalogue
as an independent piece of research work, which it certainly
will be, as all the 25000 stars will be specially re-observed
at two places in order to produce more homogeneous results.

A list of catalogues from 1755-1900, which have been used
in the compilation, is given in the Introduction. It should be
noticed that, differing from the usual practice, the correction
for eliminating the effects of the magnitude-equation has been
included in the right ascensions at the rate of '"OOS per
magnitude (on Pogson's scale of log. ratio, '4).

The magnitudes have been taken from Chandler's Normal
Uranometry (in MS. only), wherein the light ratio '36 is used
instead of Pogson's '4, hitherto almost universally used by
astronomers ; it is to be presumed that there is sufficient
reason in that unpublished work for this change, otherwise the
change is to be regretted. The result is that a magnitude-
equation determined in conformity with the Pogson scale
(log. '4) should be multiplied by 0'9 in order to reduce it to
the scale of this catalogue, or I'icc versa.

A large amount of valuable information is given concisely
in the Introduction, and there are three appendices. Appendix I
contains ephemerides of Polar stars between 1900 and 1925.
Appendix II contains important notes upon certain special
stars, mostly binaries. Appendix III, pages 279-345, has
involved almost as much work as the actual catalogue, and is
of little less importance. It gives concisely the systematic
corrections to each catalogue used, the corrections used for
magnitude-equation, and the value or weights given to each
catalogue. Altogether, it is a most valuable contribution to
accurate astronomy, as distinct from the speculative side ; it
is beautifully printed, and forms Publication No. 115 of the
Carnegie Institution of Washington. Professor Boss acknow-
ledges his indebtedness to that Institution, to Dr. S. C.
Chandler, to Mr. .A. J. Roy, Mr. W. B. \'arnum. Miss B.
Benway, and Mr. B. Boss, for their zeal and help in the work.

F. A. B.

67

6S

KNOWLEDGE.

February, 1911.

VARIABLE OR NOVA LACEKTAE (ESPIM.— The
beginning and end of the year I'ilO were characterized by
important astronmnical discov.-ries ; the beginning was by the
Daylight comet, the end b\' a bright New star, which is
appropriate at this particular season of Epiphany.

" Kiel 6.55 p.m.. received a! Oxford 7.33 p.m., December
31st, 1910.

" To University Obs._r\ator:.-. Oxford.

" Nova Lacertae Kspin Tow Law 30080 December 07359
Greenwich 33802 03744 72239 47224 Helle Linien."

Thus runs the telesiMtn received by the subscribers to the
Central Office for .Astionomical Telegrams conducted by Dr.
Kobold at Kiel. Its meaning is that the Rev. T. E. Espin.
M..A., F.R.A..S.. lornierly of Exeter College, Oxford, and now
the Rector at Wolsingham. Tow Law. near Darlington, by
assiduousiv warching the sky and examining the stars for
duplicity and variability, was able to detect the appearance
of a b::tjiit star of about the seventh magnitude near the
edge o; the constellation Lacerta, towards Cepheus, at R.A.
22" iZ'° 10" 15' 21"+52= (1911). and in the Milkv Way.
about 6 p.m., on December 30th. Reference to maps failed to
show any star in that position, and upon examination with a
-pectroscope, bright lines were noticed in such positions as
indicated the star to be a new one, or one variable in
magnitude. The evening of December 31st was very cloudy.
At Oxford, on January 1st, two photographs of the region were
taken with four exposures of a few minutes each, and the
results of the measurement of one of these plates
were communicated to the Royal Astronomical Society's
meeting on January 13th, and will be published in the Monthly
Xoticcs in February. Photometric and eye estimations of its
magnitude have been made by Mr. Espin. and at the
observatories at Greenwich, Cambridge, Oxford (both obser-
vatories). Harvard College (U.S.A.) ; the magnitude was made
out to be between 7'0 and 8'0, or one-and-a-half magnitudes
brighter than the star near it. Various observers have noted
it as "red"; the writer has not yet been able to make it
deeper than " orange." and to him it appears to have
nothing of the " Hind"s crimson," R. or S. Cephei hue about it.
The magnitudes deduced from photographic plates, however,
do not fit in with the general ideas of chemical action,
colour, and photographic results ; for, if the colour be
red or orange and less actinic to the sensitive film of a mono-
chromatic plate (with emulsion such as is generally in use for
hand-camera and extra-rapid work), one would expect to get a
smaller image of it on the photograph than of a normal star,
both being determined by photometric or visual observation to
be of the same magnitude, say se\en. But the photographs
appear to give the magnitude on January 1st and 2nd as 6'7
or 6'6, or about two-thirds of a magnitude brighter than by
other methods. During the first part of January the star
changed or lost little, if any, of its brightness,

Mr. F. \V. Dyson, the Astronomer-Royal, has received
information from the Harvard College Observatory that
the new star was visible on photographs exposed there
on November 23rd, 1910, when its magnitude was determined
to be equal to 9 Lacertae, or 5'0 photographically, and, there-
fore, quite visible without optical aid. The interesting feature
in the examination of the Harvard store of photographs, going
back many years, is that, on November 19th the star was not
visible, i.e., it was probably fainter than the eleventh
magnitude, if at all visible in the sky ; it was again photo-
graphed on December 7th, but, in spite of the large number
of telescopes, photographs, and keen observers searching the
sky, this naked-eye star was not detected until December 30th,
by Mr. Espin.

Though some are disposed to consider the discovery to be
merely that of a variable, because rumours have been current
that Dr. Max Wolf has photographs, taken nearly twenty
years ago, which show a faint star in the position of the Nova.
— but we must wait for accurate measures, before accepting
this information — there is plenty of evidence for us to
consider it to be as much a new star as others. The immense
and nominally instantaneous brightening up by eight, ten, or
more magnitudes — as in the most prominent cases of

T. Coronae (1868), Nova .Andromedae (1885), Nova .Aurigae
(1S92), Nova Persei (1901), and Nova Geminorum (19031 —
classify these Novae as being of a different order from all
known \ariable stars, though their spectra may be similar.

Two questions arise and present themselves for astronomers
to solve, now that thousands of photographs, taken during the last
thirty years, are available for reference. When is a Xova not
a Xova ? And who is to be entitled to the credit of the
discovery in such cases as Nova Geminorum and the star
which is the subject of this note ? Surely not the one who
first saw or photographed it. but the one who first drew the
attention of the astronomical world to it. t- a u

THE PRESENT STATE OF VARIABLE STAR WORK
(II). — For the sake of convenience the following survey of
variable star work has been arranged under the heading
of countries, taken approximately in the order of their
respective importance as regards this matter. I have
made no attempt to write an historical sketch and, there-
fore, have confined myself essentially to present facts. As
it may be easily understood, "absolute" completeness in such
a work is difficult to attain : many astronomers have made
purely accidental discoveries of variable stars in the course of
other duties — such as observations of planets, comets, and
double stars, zone observations, measures and comparisons of
celestial photographs — without being really interested in this
branch of astronomy, and it could be hardly possible to include
their names here. I am satisfied, however, that no essential
fact has been overlooked in the following.

Germany. — If the height of scientific activity resides in
care, spirit of enterprise, continuity, abundance and accuracy
of bibliographical sources and especially " thoroughness,"
rather than in multiplicity of discoveries, one must admit that
German astronomers, following the glorious steps of their great
Argelander, the initiator of the " science " of variable stars,
always took the lead in this branch of astronomy,

A good deal of this result, in modern years, is undoubtedly
due to the \ivid interest shown in stellar photometry by the
" Astronomische Gesellschaft," an international association of
(principally professional German. Austrian, Scandinavian and
Russian) astronomers, established in Leipzig in 1865. The
" A.G.," as it is generally named for the sake of brevity, whose
star catalogues are well known everywhere, controls three
organizations of importance connected with our special
subject.

(1) .\ "Committee on Variable Stars." at present com-
posed of Professor N. C. Duner. director of the University
Observatory of Upsala (Sweden). Professor Dr. Ernst Hartwig,
director of the Remeis Observatory in Bamberg (Bavaria),
and Professor Dr. G. Miiller, chief astronomer at the Royal
Astrophysical Observatory of Potsdam (Prussia). When,
in 1901 (See Astronoiiiical Journal, Nos. 491-492 and
Nos. 505-506), Mr. Seth C, Chandler, of Boston, to whom I will
refer afterwards, declared that he was going to give up the
important and strenuous task of collecting all available
information on variable stars, and cease to assign definitive
names to those whose elements were sufficiently known, a
work which he had carried on for years with a great skill, the
.\.Ci. Committee on Variable Stars which, at the time,
comprised also the Dutch Professor Oudemans, since deceased,
at once took over the matter and has directed it ever since
with a great exactness. Professor Miiller especially taking a
great share in the work. The Committee has made special
and very wise rules (fully explained in Astroiioiiiisclie
Xachrichten 171, 347) for the admission of suspected
\ariable stars among the number of those to which
definitive letters are affixed, the principal of them being
that the range of light variation ought to be at least
half a magnitude, that the character of this variation
must be, at least roughly, indicated, and that it must have
been confirmed by at least one other observer than the
discoverer. Save some critical views uttered by that other
well-known authority, Professor E. C. Pickering (See Annals
of Harvard College Observatory, Vol. Iv., page 87), and
which serve only to demonstrate the fact that no human work

February, 1911.

KNOWLEDGE.

69

can reach perfection, the verdicts of the Committee have
always met with the approval of the astronomical world, and
received unanimous praise.

Once a year, generallj- in the month of November or so, the
Committee publishes, in the Axtronoiiiische Xacliriclitcii.
a list of lettered variables, giving in tabular form, their name,
provisional number, position for 1855.0 and 1900.0, value of
precession, magnitudes at maximum and minimum, and
indication whether these magnitudes are visual or photo-
graphical. This list is supplemented by notes giving refer-
ences to catalogues ("Bonner Durchmusterung," or "'A.G."
numbers), indicating the name of the discoverer and
"supporter," and giving a short historical sketch, with
elements, colour, and other notes.

(2) The Astronomische Nacliriclitcn (.4.A'.), the lead-
ing astronomical paper of the world, is published at Kiel
(Schleswig-Holstein), at the rate of one or two numbers,
generally of eight pages (or si.xteen " columns " as they are
numbered) a week, twenty-four numbers forming one volume.
The character of this paper is thoroughly international and,
though many papers are printed in the German language.
French, English, Italian, Spanish, and even Latin memoirs
are not uncommon. The Astroiioniisclie Xachrichten.
founded by H. C. Schumacher, in 1821, September, and
therefore the oldest amongst astronomical journals, is about to
publish its one hundred and eighty-seventh volume Icomnienc-
ing with Xo. 4465, issued 1911, January 12thl, and is under
the editorship of Professor Dr. Hermann Kobold, astronomer
at the Observatory of Kiel's University, who also directs the
Cciitralstelle for the centralization and circulation in
Europe of astronomical news. The collection of this paper
includes also seventeen more or less extensive complementary
numbers or Ergaiiznngshefte and six general tables of
contents, a seventh being in course of preparation, as well as
reprints of some old volumes.

The Astronomische Kachrichtcn contains the greatest
part of variable star information and has, for a long
time, been the medium through which new discoveries
of these objects are announced to the world. In
order to avoid confusion and to permit easy references.
Professor Kreutz, the fourth editor of the paper (the
first was Schumacher), decided, in 1900, to affix a " pro-
visional number" to new variables, pending their definitive
lettering by the "A.G." Committee. This series of numbers is
begun again every year, from No. 1, the name of the year being
affi.xed to the number. So, for example,

BD + 7 929 = 47.1910 Orionis=RT Ononis.

This is a similar method to that followed for new
asteroids, save that a reverse system is in use ; newlj--
discovered small planets receive a double letter with the
year prefixed, and are afterwards numbered and named.

(3) Some years ago the " Astronomische Gesellschaft."
represented by its committee on variables, decided to compile
and pubhsh a great catalogue of these objects. As will be
seen afterwards, works of this kind have been planned and
partly printed elsewhere, but it may be confidently assumed
that the bibliographical task now undertaken in Germany will
go far beyond all that has been done till to-day, and will
form a standard work, whose value, as it approximates to
completeness, can hardly be overrated.

The catalogue will be divided in four great sections: — 1(tI
Variable stars; (6) Suspected variable stars; (c) Variable
stars in clusters; (d) New or temporary stars; dealing with
one thousand objects. Other somewhat abridged mono-
graphs will deal with newly-discovered variables, for which
the available material of observation is less abundant. The
work will give for each variable the '" complete" bibliographical
sources and references, and a thorough discussion of all
published (and, in many cases, unpublished) data. It will not
include however, some well-known variables on which com-
plete monographs have already been published, such as
0 Mira Ceti (Guthnick), x Cygni (Rosenberg), 5 Librae iKron),
R Coronae (Ludendorf) and U Geminorum Ivan der Biltl.

The discussion of this formidable material, always kept up
to date, has been divided among a number of fellow-workers.
At the time of writing, the MSS. for seven hundred stars is

ready, two hundred are under discussion, and one hundred
are still in abeyance. In the course of its twenty-third meeting,
recently held in Breslau (see " Knowledge," 1910, November
and December), the Society voted a sum of 1,000 marks (i,50)
towards the continuation of the work, and 10,000 marks
(£500) towards the cost of printing the first part, which may
be expected to appear in the course of the present year.

Felix de Roy,
Honorary Secretary " Societe d'Astror:o:iiie d'Anvers."

( To he continued.)

BOTANY.

By Professor F. C.-wers, D.Sc.

EOCENE FLORAS. — In a recent paper on "An Eocene
Flora in Georgia, and the Indicated Physical Conditions,"
Berry iBot. Gaz., vol. 50, 1910), draw-s an interesting
comparison between the Eocene floras of Em'ope and
North America. The Middle Eocene floras of North America,
like those of Europe, show distinctly tropical characters,
which are absent in the earlier or Lower Eocene. These
chiiracters first become marked in the fruits from the London
Clay and the leaves from Alum Bay, and in corresponding
deposits on the Continent. These floras show much closer
affinities with the modern floras of Malaysia and tropical
.America than with those of Australia — the supposed
Australian affinities of the Eocene floras may now be regarded
as an exploded myth. The Eocene genus Nipadites
corresponds exactly with the modern Palm genus Nipa. which
inhabits the tidal waters of the Indian Ocean, and ranges
from India, through the Malay Archipelago, to the Philippines.
The Xipa sv\amps of the Eocene period ranged northwards in
Europe to southern England, and though Nipadites does not
occur (so far as known) in the Eocene of America, the latter
shows various forms, either identical with, or allied to, the
plants associated with Xipcidifes in the Eocene of Europe,
including various tropical Ferns. The existing flora of
Florida, the Bahamas and Bermuda contains a large element
which has been derived in comparatively recent geological
times from the south, but the main elements of these modern
floras were already in existence in the Middle Eocene, if not
earlier. There is abundant e\ idence that nearly all modern
plant families, excepting such specialised forms as the
Orchidaceae among Monocotyledons and the Compositae and
their allies among Dicotyledons, were at one time more widely
distributed than they are at present, and that the details of
modern geographical distribution represent in a less degree
the interchange of types between different areas than they do
the greater or less degree of segregation of descendants of
forms once spread over much wider areas. The strictly
modern mo\ement of the subtropical flora along the course of
the Gulf Stream has been from the south, northward, as the
various coral islands of the Bahamas became evolved. This
dispersal was preceded by a similar spread of the tropical
flora on a much more extended scale during the early Tertiary.

AFFINITIES OF CACTACEAE.— The Cactaceae have
attracted a large amount of attention recently. A special
German journal has been founded to deal exclusi\ely with
this family of plants, and some interesting observations and
speculations have been made by \arious writers regarding the
affinities of the family and its position in the natural system.
The Cactaceae have for long been regarded as an isolated
group of obscure affinities, and in different systems of
classification they occupy very ^-arious positions. Although
the Cactaceae are highly specialisedasregards their vegetative
characters, there are many features in their floral structure
that indicate affinities with the cohort Kanales, w^hich includes
the orders Nymphaeaceae (Water-Ulies), Magnoliaceae (Tulip-
tree, and so on), and Ranunculaceae, besides others. The
most striking of these " Ranalian " characters are : (1) the
numerous spirally arranged sepals, petals, stamens, and
carpels : (2) the occurrence in some cases of a gradual
transition from sepals to petals ; (3) the insertion in some
cases of the sepals and petals on the outer surface of a
receptacle cup in which the carpels are embedded. There is

70

KNOWLEDGE.

February, 1911.

an especially striUing similarity between the flowers of such
Cacti as Pilocereiis and such Nyniphaeaceae as Victoria
and Euryulc. The suggestion ol ;i " Raualian " ancestry for
the Cacti, based on the structure of the flowers, is greatly
strengthened by the recent work of Miss de Fraine (Ann. Bot..
IQlOi on the structure of the transition region between stem
and root in the seedliny- of various members of this order.
It was found that in tht so c'acti which have the least modified
seedlings — those in v.hich we should expect to find that
ancestral characters would be retained — the same t\-pe of
transition of the vascular bundle system occurs as in certain
Ranunculaceae. Miss Sargant (Ann. Bot.. 1900) showed
that this particui.sv zyve of transition structure pointed to the
origin of the >ic:-jcotyledon3 from Dicotyledons allied to
Kanuncul.iceae.

CHKMl.S FRY.

B\- C. .\INSW0RTH Mitchell. B..\. lO.xon.), F.I.C.

STl- KILISATION OF W.\TER BV MEANS OF
ULTRA-VIOLET RAYS.— The use of ultra-violet rays for
the effective sterilisation of large quantities of water has been
made the subject of several recent patents, and processes
based upon the principle have been adopted in many places.
It has been demonstrated by Messrs. L'rbain, Seal and Feige,
iCuniptcs Rend.. 1910, CLI., 770.) that the most important
factor in this method of sterilisation is that there should be
uniform exposure of the particles of water to the source of
light. In some types of apparatus this condition is attained
by enclosing the mercury vapour lamp in .a box with three
quartz sides, round which the water is made to flow in a
semi-circular trough in such a way that it moves alternately
towards and away from the lamp, which forms the centre of
the semi-circle. Again, in the apparatus constructed by
Urbain and his collaborators, the water is made to circulate in
a spiral within a cylinder about two-and-a-half yards in
diameter, the opening into which is concentric with its axis.
The water being forced into this cylinder at a tangent, whorls
round so as to leave a nearly vertical cavity in the centre, and
within this is suspended the lamp. Under these conditions,
the maximum distance of the water from the source of light is
about forty-two inches, and the minimum distance about
three-and-a-half inches, while the period of exposure is about
three minutes. The positive electrode of the lamp is composed
of aluminium, coated with a thin layer of iron, while the
negative electrode consists of carbon. The yield of sterilised
water obtained from an apparatus of this Uind ranges from ten
to fifty cubic metres per hour, the average quantity being
about twenty metres. A sterilising plant based upon this
principle has been erected at N'euilly-sur-Marne, and gives a
supply of sufficiently sterile water at an expenditure of twenty
watts per cubic metre.

THE WATER OF GREAT SALT LAKE.— An interest-
ing series of analyses of water from Great Salt Lake is
published by Messrs. Ebaugh and MacFarlane (/. hid. Eng.
Chain., 1910, II, 4541, showing the variations in the amount of
saline constituents during the last forty years. During the
four years of drought ending in 1904, the level of the water fell
to such an extent that the idea of the lake becoming dry was
seriously entertained ; but after the succession of wet years
since that date, there is more likelihood of the surrounding
country becoming flooded. These extremes are reflected in
the composition of the water at the different periods, the
specific gravity and the total solids showing an enormous
decrease since the close of the dry period. Thus, in October.
1903, the water had a specific gravity of U2206, and contained
3,iiS'36 grammes per litre of total solids, whereas in October,
1909, the specific gravity was ri561, and the total solids were
only 242'25 grammes per litre. The composition of the water
varies at different periods of the year, the proportion of
dissolved salts being greater in the autumn.

A NEW METHOD OF PREPARING ARfiON.— A rapid
method of obtaining large quantities of argon is described by
M. G. Claude in a recent issue of the Coniptcs Rend..
(1910, Vol. CLI, 752). Oxygen obtained in the liquefaction
of air is used as the source, for it has been found that the

chief impurity in the oxygen is argon, the volatility of which is
intei-mediate to that of oxygen and of nitrogen. To separate
the argon, which then often exceeds three per cent., the oxygen
is absorbed by means of copper, and the nitrogen by magnesium.
For this purpose the gas is passed through a red-hot copper
tube charged with reduced metallic copper and copper filings,
and on leaving this passes through a red-hot iron tube
containing magnesium powder. Lastly, it is passed through a
tube of silica containing copper oxide to absorb any hydrogen
derived from moisture in the oxygen or in the copper. From
eight to twelve litres of pure argon may be obtained by means
of this apparatus in about two hours, after which the copper
becomes spent, and must be regenerated by a current of
hvdrogen.

'the SOYA BEAN INDUSTRY.— The importance of
soya beans as a new commercial product may be gathered
from the fact that during the year 1909, upwards of five
hundred thousand tons were imported into this country from
China, and were utilised in the manufacture of oil and of seed
cake for cattle. Prior to 190S only small consignments had
been imported, but the great scarcity of fats and oils required
for the manufacture of soap induced the manufacturers to
make experiments with every kind of oil, and as soya bean oil
was found well suited for the production of soft soaps and, in
admixture with other fats, for hard soaps, it speedily estab-
lished its present position. The beans, which are used in
China and Japan in the preparation of soy sauce and other
food products, yield, when pressed, about 10 per cent, of a
vellow oil, which has weak drying properties and possesses
many points of resemblance to cotton seed oil. The oil is
used for food in China, and has been tried for the same
purpose in this country, .attempts have also been made to
employ it in place of linseed oil in the manufacture of paints
and linoleum, but its inferior drying properties h.ive prevented
its application in this direction. The beans contain about
forty per cent, of protein substances and twenty-three per
cent, of carbohydrates, and the residue from which the oil has
been expressed is thus a valuable feeding stuff'. Unsuccessful
attempts have been made to acclimatize the soya bean in
Germany, but the plant has already been introduced into
West Africa and the southern part of North .America, with
every prospect of success.

GEOLOGY.

Bv Rfssi;i L V. (iwiXNELL. B.Sc. A.R.C.S.. F.G.S.

A CENTRAL AFRICAN GLACIER of Triassic age is
dealt with by Messrs. Ball and Shaler in the Journal of
Geology, November-December, 1910. The glacial features
occur in the Lubilache formation of the Belgian Congo (better
known as the "Congo Free State"). This formation consists
mainly of alternating beds of sandstones and shales of Triassic
age. It is concluded from the evidence that a glacier or
glaciers pushed in a tongue down the present valley of the
Lualaba Ri\er ; from the fact that large boulders probably
dropped by icebergs are found at least two hundred feet abo\e
the base of the formation, it is believed that long after the
glacier had retreated toward the south, glaciers still existed to
the south-east. This glacial epoch must therefore have been
of a considerable duration.

The glacial features presented are : —

(1) Striations having the characteristics of glacial striations,
on pebbles in the basal conglomerate of this series, indicating
morainal origin.

(2) The tongue-like form of the basal beds and the character
of this conglomerate, including the size of the boulders, the
lack of assortment, the patchy arrangement of the material and
the preponderance of boulders of local origin.

(3) Erratic boulders, presumably dropped by icebergs,
occurring in shales of this series.

(4) Probable glacial scratches, crescentic gouges and smooth-
ings on the surfaces of older rocks upon which the Lubilache
was laid down.

IGNEOUS ROCK COMPOSITION.— Several petrologists
have calculated, from large collections of published analyses,
the " average composition " of an igneous rock. In some

February. 1911.

KNOWLEDGE.

71

cases no account is taken of the relative masses ot the rocks
represented by the analyses, in others these relative masses are
reckoned with as far as possible. By the former method the
average igneous rock appears to have a composition close to
that of many pyroxene andesites and quartz-mica-diorites : in
passing it is interesting to note that these are extremeh' conunon
rock types. By the second method Professor Vogt finds the
average rock to be far more acid — with about 74% of silica —
and thus corresponding with a granite in this respect. In " An
Introduction to Petrology" (19101, Mr. F. P. Mennell tackles
the subject by this second method, dealing with the rocks mapped
in the neighbourhood of Bulawayo, in Rhodesia. Putting
minor rock types into one or other of larger groups, he estimates
eleven thousand nine hundred and sixty square miles of igneous
rock (assumed to extend one mile vertically downwards) to
be made up as follows : — Granite, eleven thousand six hundred
and seventy cubic miles : syenite, forty ; picrite, two hundred
and forty ; dolerite and basalt, ten ; and the average silica
percentage becomes nearly seventy. If this is fairly repre-
sentative of other large areas of the earth, it would indicate
that granite represents the average composition of the igneous
rocks.

A somewhat similar problem is attacked by R. .A.. Daly in
" The Average Chemical Composition of Igneous Rock Types"
(Proc. Anier. Acad. Arts and Sciences, xlv., 1910'. The
author, using various collections of analyses, calculates the
average chemical composition of ninety-eight principal igneous
rock types, and incidentally these may be used as a basis for
finally calculating the " average igneous rock." The relative
uniformity in the soda percentage of the more abundant types
is specially noted in its bearing on the origin of oceanic
sodium, and therewith, on the problem of the age of the earth.
The striking similarit\- of the axerage granite analysis to the
average analysis of the base (ground mass) in augite andesite.
and the equally close resemblance of the average diorite
analysis to the arithmetical mean of a\erage basalt and granite,
are illustrated.

The same author discusses the " Origin of the Alkaline
Rocks" in Bulletin Geol. Soc. America, xxi. (1910). It is
usually recognised that there are two great branches of igneous
rocks — the " alkaline " (rich in soda and potash), corresponding
in a general way with the areas of the Atlantic type of coast-
line .as defined by Suess, and the '" sub-alkaline " or " lime-
alkaline," corresponding with the Pacific type. In the present
paper. Dr. Daly states that no alkaline province can be
described .as free from sub-alkaline eruptives. especially those
of basaltic or granitic types. Emphasis is laid on the
indisputable fact that the visible volume of all alkaline rock-
bodies is a very minute quantity as compared with the visible
volume of sub-alkaline eruptive bodies. An inductive study
shows that most alkaline rocks cut thick masses of limestone
or other calcareous sediments. This fact suggests the
hypothesis that the absorption of carbonate disturbs the
chemical equilibrium of sub-alkaline magma in such manner
that alkaline fractions are produced by differentiation. Most
of the alkaline species are ascribed to the interaction of
basaltic magma and limestone (or dolomite), but more acid
magma is also sensitive to the solution of carbonate. The
hypothesis explains the concentration of alkalies, the desilica-
tion shown by the crystallisation of nepheline, leucite,
corundum, and so on ; the extreme variability of alkaline
bodies in mineralogical and chemical composition, the
occurrence of such lime-bearing materials as melilite, scapolite.
melanite. and so on, and COj-bearing minerals, as cancrinite
and primary calcite.

,\lkaline rocks of exception.al interest are found in Ayrshire,
and neighbouring parts of Scotland. .\ preliminary account
of some of the types is supplied by Mr. G. W. Tyrrell {Trans.
Geol. Soc. Gtasgoic. vol. xiii.. pt. iii.), who promises a more
detailed paper on the subject. Teschenite. essexite and
trachyte are among the types, and some of the rocks contain
much analcime, which appears to be primary. Thus there is
an analcime syenite, composed principally of soda-orthoclase.
albite and analcime, with purple titaniferous augite. barkevi-
kite and aegerine. Another rock is composed principally of
analcime, with a little nepheline, crow ded with perfect euhedral

barkevikite, sometimes with a little titaniferous augite and
plagioclase.

In the Geological Magazine for Januar\% 1911, Mr. F. P.
Mennell describes dolerites of Rhodesia, containing quartz,
either in separate granules or in the form of niicropegmatite.
The dolerite dykes penetrate the great .granite masses of the
country, and the quartz, when occurring in good-sized corroded
fragments, is obviously derived from the granite. In the case
of the smaller granules and the micropegmatite, the origin of
the quartz is not so clear. The phemonena are, in some
respects, closely similar to those which Professor Judd recorded
in certain cases, which seemed to him to prove the secondary
origin of micropegmatite and the growth of crystals in rock's
after their solidification (O.J.G.S.. May, 1889). In the
Rhodesian rocks there is clear evidence that the micro-
pegmatite fringes represent the sur\ iving portions of crystals
which have had their exteriors melted or corroded. " The
outgrowths are, therefore, as Judd correctly surmised, of
the nature of secondary enlargnients long after the consoli-
dation of the original nucleus. Where his suggestion was at
fault, was in regarding the regrowth as having taken place at
the expense of a non-crystalline ground mass. The outgrowths
that we have been discussing are clearly due to the re-crvstal-
lisation, under the influence of heat, of the exterior portions of
the original crystals, together, in some cases, w ith materials due
to reactions with the surrounding crystals or with introduced
substances. The light such an observation throws on the
occurrences of quartz and micropegmatite among basic rocks,
and upon the frequently-noted association of gabbro or
dolerite with granophyre. is evident. There seems little doubt
that it may usually be ascribed to the partial admixture, prior
to intrusion, of acid and basic materials, not necessarily from
related magmas, or even entirely of igneous origin."

Very similar rocks to these Rhodesian quartz and micro-
pegmatite-bearing dolerites were described in the same
magazine in July and -August, 1909, in Mr. G. \V. Tyrrell's
" Intrusions of the Kilsyth-Croy District." These rocks, from
Dumbartonshire. Scotland, are described as granophvric
diabase, and the grains of quartz and patches of micro-
pegmatite are said to be primary. It is here suggested that
the gabbro-granophyre melange rocks owe their origin to the
interaction of a normal basalt-magma with a highly siliceous
country rock, and that the normal granophyric diabases,
with their remarkably constant chemical composition, represent
the saturation-point of such a magma with silica. The excess
of siliceous matter is believed to be thrown out as a separate
body of material, usually consolidating as granophyre, in a
manner analagous to the separation of the excess of a salt in
a saturated solution.

While dealing with rock-magmas and solutions, reference
may be made to a paper in the American Journal of Science
for January, 1911, — "Solid Solution in Minerals, with Special
Reference to Xephelite," by H. W. Foote and W. M. Bradley.
It is a well-known fact that there are certain minerals to
which no satisfactory chemical formulae can be assigned,
which agree with the results of analysis. In general, the
composition of a mineral, as obtained in analysis, \aries from
the composition of the ideal pure compound for two reasons,
apart from errors of analysis. Either there is la I isomorphous
replacement of one element or radical by another, or ibj
there are mechanical impurities present. The authors call
attention to another influence, which must probably be
taken into account in cases like that of nepheline (to which
the formulae XaAlSiOj and Na<.-\lsSi<iOM. besides others
more complicated, have been given). It is assumed that
in certain cases a substance on crystallising forms a solid
homogeneous solution with foreign matter, which is neither
isomorphous with any constituent, nor can be regarded as a
mechanical mixture. It can be compared to the solution of
salt in water, in which the salt takes on the appearance and
form of the water without taking any part in the formula of
the water. The authors maintain that the pure compound,
which forms the basis of nepheline, is the orthosilicate
Xa.AISiOj. and that the observed variations from this are
due to silica dissolved in the silicate. Just as very little is
known about the condition of dissolved substances in liquids,

72

KNOWLEDGP;.

February, 1911

as to whether they are combined with the sal\'ent. so in this
case it is impossible to say whether the silica is present as
dissolved albitti or silica, or leucite, or in any other form.
The excess of silica which cm be taken up by nepheline to
form a saturated solution can apparently be determined.
Where albite is found iiiii::iately mixed with nepheline it is
evident that the nepheline must be saturated with silica, and
the excess of the l.uter lias formed albite. The authors
suggest the applic.ition of their arguments to other minerals,
and state that work ha.s already been begun on pyrrhotine,
the magnetic sulphide of iron, the formula of which is
variously given r.s FenSi, FctS^, and so on. In this case,
analyses ^■ary i'r ..ii Fes So up to FeinSn, while conforming to
thegeneralfonii;:: I FenSn+i(Dana's"Textbook of Mineralogy").

B\

METEOROLOGY.

John A. Curtis, F.R.Met.Soc.

The vv-eather of the week ended December 17th was rough
and squally, with high temperature and much rain. Of the
twelve districts into which the British Isles are divided for
meteorological statistical purposes, five were noted as being
\-ery unusually warm, six as unusually warm and only one
(Ireland S.I as moderate.

The excesses above the average varied from J°-5 in the
English Channel to 9"-l in England E. The highest maximum
was 57° which was recorded at Geldeston and also at Jersey,
but in all districts readings of 50' or upwards were recorded.
The lowest readings were 30" at Strathpeffer and Nairn on
December 16th, but at no other stations in the British Isles
did the temperature fall below the freezing-point. The rainfall
was in excess in all districts, except Scotland N., where it was
but little more than half the normal amount. In England S.E..
the rainfall was three and a half times as much as usual. At
many stations rain was measured each day, and at Llangam-
march Wells, the total for the week was as nuicli as 4-74
inches. Sunshine was generally below the average ; in many
places very much so. .\t Westminster, the total duration was
2-9 hours, or 5%. At Greenwich it was 67 hours or 12",,.
There was much strong wind during the week, and on the 15th
there was a severe and widely-spread gale. The temperature
of the sea water varied from 51° at Salcombe to 41° at
Cromarty.

The week ended December 24th was mucli drier th.m those
which had preceded it; still rain fell frequentl>', and at several
stations on every day. The aggregates were less than the
average in all districts except Scotland N., where it was
double the usual amount. In England N.E., the rainfall
amounted to only 0-08 inches, or less than one-sixth the
normal. Temperature continued high, and there was excess
in each district, as much as 5-0 in Scotland E. The highest
reading recorded was 57°, but in all districts readings of 53°
and upwards were recorded. The lowest minimum was 27°,
at Swarraton, Hants. Bright sunshine was also in excess
generally, though some curious anomalies were reported : thus,
for instance, at Birr Castle the total duration was 8'2 hours in
excess, while at Dublin it was 7'0 hours in defect. The mean
temperature of the sea water was higher than in the corres-
ponding week of last year by as much as 5° at some stations.
The individual readings ranged from 51° at Salcombe, to 40
at Pennan Bay and at Cromarty.

The weather of the last week of the year was imsettled, but
there were bright periods in most parts, and several dry days.
Temperature was rather above the average as a rule, and
readings of 50' or above were recorded in all districts except
Scotland E. The highest maximum observed was 53° at
Killarney and at Jersey, while on the other hand the lowest
recorded was 18° at West Linton, on the 28th, and 19° at
Llangammarch Wells on the same day. On the grass the
temperature fell to 8° at Llangammarch Wells, to 15° at
Tunbridge Wells and to 16° at several places. Rainfall was
scanty except in Scotland N., the amounts in many places being
one-fourth or less of the average ; at Leith the total for the week
was only Q-Ol inch. Sunshine was generally in excess, and
the largest aggregate recorded, namely 25'3 hours, at Hastings,
was 47% of the possible duratiem. On the other hand, at

Westminster the total duration was only 2-7 hours or 5 %.
The sea temperature showed a considerable decrease as
compared with the previous week and ranged from 50" at
Scilly and Plymouth to 39° at Cromarty.

The weather during the first week of 1911 was generally
dull .aid wet, except in the North-West, where it was dry and
fine. Temperature was below the average, except in England,
N.E., where it was 0°-2 in excess. The defect was, however,
as a rule, not of great amount. Individual readings exceeded
50° in most districts, and in Ireland S., on the 7th, 52° was
reported, both at Killarney and at Valencia. Frost was
experienced in all districts except the English Channel. The
lowest of the minima were 16° at Balmoral. 20° at Nairn,
West Linton, and Strathpeffer, and 21° at Birr Castle and
Cahir, in Ireland S. The readings on the grass were as low
as 9° at Llangammarch Wells, and 14' at Balmoral. Rainfall
was above the average in England N.E., E., and S.E., but
was deficient elsewhere. In Ireland S., the aggregate fall
was but little more than half the usual amount. Sunshine
was, as usual, greatest where rainfall was least; the percentages
of its possible duration ranged from 14% in England, N.E., to
37% in Ireland N. At Westminster the total duration of
Sunshine for the week was only 0'6 hours. At .\berdovey it
was 2Z'2 hours. A severe thunderstorm, accompanied by
snow and hail, was experienced in Norfolk during the early
hours of January 2nd.

The week ended January 14th was unsettled, with rain during
the earlier days and sleet and snow later. Temperature was
below the average in England S.W., English Channel, and in
Ireland, but abo\e it elsewhere. The departures from the
mean, however, were not large. The highest reading was
54 at Killarney on the 8th, and temperatures of 50° or upwards
were reported from each district. The lowest minimum was
22 .at Kilmarnock and at Cally, Gatehouse, on the 13th. At
several other stations the readings were below 25°. On the
grass the temperature fell to 12° at Newton Rigg. and to 14" at
Tunbridge Wells. Rainfall also was not far from the mean,
being below it in the Midlands, England S.W. and in Ireland ;
e(iual to it in England N.W.. and above it in the other districts.
The heaviest fall was on the 10th when 1'36 inches fell at
Poltalloch, 1-17 inches at Fort William, and 1-04 inches at
Aspatria. Sunshine was in excess in all districts except Scotland
N., where it was slightly in defect. The greatest divergence from
the mean was in England S.W., where the district value for
duration was 17 hours as compared with an average of 10 hours.
,'\t Westminster the aggregate was 8T hours (15%) ; at
Falmouth 23'8 hours (42%). A thunderstorm occurred at
Newcastle-on-Tyne on the 12th. Aurora was seen in Scotland
on the 8th. The temperature of the sea water varied from
49 at Scilly and Plymouth to 36" at Cromarty.

THE RAINFALL OF 1910.~Dr. H. R. Mill, of the British
Rainfall Organization, has an interesting article in the last
number of Sv;;K)«s's Meteorological Magazine upon the Rain-
fall of the past year. The year was a wet one in nearly all
parts of the Kingdom. The principal parts of the country
having less than the average amount were Western Ireland
(Counties Galway, Mayo, and part of Clare) ; Western Scotland
(.Argyll and the Western islands), South-Eastern Scotland
and North-Eastern England; and a narrow strip on the coast
of South Wales. Each country, however, had an excess,
England and Wales of 11%, Scotland 2%, and Ireland 9%.
For the British Isles, as a whole, the excess was 8%,
February was the wettest month, with 61% excess, and
September was the driest month, with 69% defect.

September, 1910, was one of the driest Septembers on
record, and February was one of the wettest Februaries.
The total rainfall for the ten months, January to September,
was almost exactly equal to the average fall for the whole
\'ear.

Since 1889 there has been a marked sequence of two dry
years followed by one wet year, but this relation has now
broken down, and we have had two wet years in succession.
Dr. Mill adds: "It seems possible that the swing of the
pendulum is carrying us into a period of predominating wet
years, corresponding to the wet period of 1874-1883,"

February. IPIO.

KNOWLEDGE.

73

MICROSCOPY.

By A. W. Sheppard, F.R.M.S.,
with tJic assistance of the foUoicing in icroscopists : —

Ar'ihur C. Eanfield

James Burton,

The Rev. E. W. Bowell, M.A.

Charles H. Caffvn.

Arthur Eari.and, F. R. M.S.
Richard T. T.ewis, F.R.M.S.
Chas F. Rousselet, F.R.M.S.
D. J. Scoureield, F.Z.S., F.R.M.S.

C. D. Soar, F.R.M.S

DR. ERNST LEITZ. — We have much plea.sure in
announcing that the University of Marburg has conferred the
degree of Doctor of Philosophy
honoris causa upon the principal
of the optical works, Wetzlar.
We congratulate Dr. Ernst Leitz
on his well-deserved honour.

A NEW MICROSCOPE
LAMP. — The lamp consists of a
five-inch circular base, having a
telescopic square vertical tube
about si.x inches long, formed of
two square tubes sprung so as to
slide the one within the other.
The outer tube is plugged at the
bottom with brass and terminates
in a three-eighths inch brass
screw, fitting into a hole tapped
in the base to receive it. This
is turned up square at the
bottom to ensure the upright
tube being truly vertical. The
inner tube is plug.ged at the top
and terminates in a square boss
bored and tapped (three-eighths of
an inch thread! brass on two faces,
butnot rightthrough — thetwo holes
communicating with each other
to pass gas, but not permitting gas
to go into the inner tube. One
face of the boss carries a one-and-
a-half inch length of three-eighths
inch tube having an ordinary three-
eighths inch burner elbow screwed
on to it. The other face has
screwed into it a wooden nipple
bearing a three-eighths inch
screw, and formed to take a
rubber tube. The nipple should
be of hard wood in order that
the heat of the lamp is not con-
ducted to the rubber tube. The
burner elbow projects downwards
with a male thread three-eighths
of an inch and takes an ordinary
bijou incandescent burner of from

thirty-five to forty candle power. In place of an ordinary glass
shade, an opaque shade of one-and-three-quarter inches brass
tubing is constructed, cut to take a projecting window for
various light modifiers of glass three inches by one-and-a-half
inches. Three holes in the top of the shade to match screws in
the burner serve to attach it. The whole shade is chemically
blacked to keep back extraneous and unnecessary light. As
the ordinary lamp is seldom of more than four-and-a-half to five
candle power the gain in illumination is very great, and the
light being white instead of yellow, still further accentuates the
advantage. For dark ground and polariscopic illumination,
or that of opaque objects, the gain is enormous and. the
mesh of the mantle in these cases forming no disadvantage,
it can be reconmiended. It is not put forward for critical
illumination with high powers but for more general use,
where a brilliant rather than a critical light is desired.

With the siUer side reflector the results are singularly

bright and beautiful. As the gas does not traverse the
upright tubes, it can be used at any height either above or
below the stage.

Chas. E. Heath. F.R.M.S.

ROYAL MICROSCOPICAL SOCILTV.— December 21st,
1910, Mr. E. J. Spitta, L.R.C.P., vice-president, in the chair.
W. R. Traviss : .^ iviiall microscope lamp, particularly suited
for opaque objects and dark-ground illuniniation with high
powers. The light used was a small inverted incandescent
burner, carried at the extremity of a short arm. that could be
easily moved up and down on a standard. The hglit could be
brought \ery close to the table or raised to illuminate opaque

objects on the stage. — M. J. Allen:
.^n easy method of treating
printing-out paper for all kinds of
photography. The author recom-
mends that the prints be washed
in a strong solution of salt, then
placed in a saturated solution of
hypo., after which they are to
be washed in running water. —
Chas. H. Higgins: A new system
of filing slides. — A. .^.C. E. Merlin:
On the measurement of Grayson's
new ten-band-plate. The plate,
comprising ten bands running from
inVuth to TurrMirth of an inch,
had been ruled by an improved
machine, and was found to be
much better even than Grayson's
earlier productions. The author
in measuring the bands used a
selected objective of 1-32 N.A.,
having an initial magnification of
one-hundred-and-forty-three on a
ten-inch tube. A Nelson-Powell
screw-setting micrometer, which is
alone suitable for the purpose,
was used. The result obtained
was that the variation from the
mean in the spacing of the lines
did not exceed narrViTTj-inch. The
mean diameter of the lines was
•00002488-inch. The author also
made a series of measurements
with one-inch, half-inch, and
quarter-inch objectives, and came
to the important conclusion that
low powers were unsuited for
micrometry. — Jas. Murray: Some
African rotifers — Bdelloida of
tropical Africa. Thirty-three
species of Bdelloids were obtained
from dried moss, sent by Mr. A.
Allan and Sir Philip Brocklehurst,
from British East Africa. Nine
of the species are new to
science. Several of them have very distinct characters, not
previously noted for any Bdelloids. Habrutrocha caiidata
has a tail-like process, the function of which is unknown.
The animal secretes a protective shell, and the "tail" is
enclosed in a .slender tube, open at the end, so that the shell
has two openings. Habrotrocha acornis has no trace of
spurs, otherwise universal in the order. Several other species
approach it in this respect, having the spurs reduced to minute
papillae. Habrotrocha aiiriciilata, when feeding, has at
each side of the head a peculiar ring-like auricle, giving it the
appearance of a two-handled vase. The nature and function
of the auricles remain unknown. Their form, even, is difficult
to interpret, as they present apparently contradictory appear-
ances from different points of view. The Bdelloids take a
very important place in moss-faunas. In every country they
are abundant, and in most regions there is a fair proportion of
peculiar species. When more fully known, the Bdelloids seem

Figure 1.
A New Microscope Lamp.

74

KNOWLEDGE

February. 1')11.

likely to p;-o\. .i yroup of hitherto unsuspected iniport:ince,
both in point of numbers and diversity of forms. .\U these
moss-dwellers can revive after desiccation. The adult animals
become dormant when depri\ed of moisture and re\i\e when
re-moistened. It is not. as ;^:ich,irias concluded from his
experiments in 18S5, that the survival of the species is effected
by means of eggs.

Mr. A. Earland ga\e a lantern lecture dealing with the
apparatus and meth ids employed in the cruisers of the Inter-
national North Sea Commission, with special reference to the
Work of the '■ Goldseeker." the cruiser of the Sc'ltti^ll branch
of the Commission.

THE MICiv -^!-^)GIST. — We ha\ r to acknowledge the
receipt from the publishers. Messrs. Flatters. Milborne and
McKechnie. Ltd., of the third part of their quarterly. It well
maintain? the character set in the previous parts and contains
full practical details for the staining and mounting of animal
and vegetable tissues, such as the pinnae of Ferns and the
head of the Crane-fly and Hive-bee. Pages 35-37 are de\oted
to the methods adopted for embedding in Celloidin. and the
catting and staining of such sections as those of the head of
ilie Blow-fly. There are collotype reproductions of photo-
micrographs of several of the objects described. Mr. Chas.
Turner, F.C.S., contributes an article on Collecting and
Preserving Fi^eshwater .Algae. \Ve much regret to see so
many errors in the printing cf scientific names, and would
suggest to the publishers a more careful revision of the proof
sheets.

N\'e have also received a selection of the slides illustrated
and described in Parts 1-3. and can reconnnend them both
for c|uality and moderate price. The slides received with
Part 3 are: vertical section of the head of the blow-fly, the
pinna of Aspidiuin Filix-nias. stained and mounted entire,
and the fruiting spike of SchTi;iiicl!a sp., showing macro-
and micro-sporangia.

THE PREPARATION OF A ROCK SECTION.— When
commencing the preparation of a rock section, either by liand
or with the aid of a machine, the first thing to be done is to
procure a suitably-si2ed chip or slice. The si^e I usualh- start
with is from three-quarters of an inch to one inch stpiare.
This will probably lose a little in grinding, but will be a fairlv
large piece when finished.

If the work is to be done entirely by hand, it will be found
possible in most cases to strike off suitably-sized chips with a
trimming hammer, or by the aid of a chisel. The thinness of
these chips will depend entirely on the texture of the rocks,
and while it will be found comparatively easy to get large
flakes off fine grained rocks, such as basalts or andesites, it is
difficult to get even thick lumps off the coarse granitoid rocks.
With the slitting machine, described and illustrated in
"Knowledge '" for January, page 30, however, it is easy to get
slices about n^nd of an inch, or even less, and it will be seen
at once that this saves a lot of time in grinding.

The method usually recommended for using a slitting disc
is to rub the edge with powdered diamond or bort, made into
a paste with oil so as to incorporate it in the soft iron to make
the cutting edge, but I have found a much easier and cheaper
way is to apply a paste of carborundum and water witli a
camel-hair brush to the cutting edge just above the rock speci-
men. The grade of carborundmn I use for this purpose is
No. 150, which cuts fairly fast, and I find by actual timing that
I can get through an inch of any ordinary igneous rock in
from six to eight minutes without undue exertion.

When starting to cut a slice with the machine the rock is
clamped in the holder in the proper position, so that the piece
can be cut in the direction required, and the spindle is then
screwed forward so that the rock projects over the cutting
edge of the disc. The disc is made to revolve toward the
operator, the edge is wetted with the carborundum paste, and
the rock is then allowed to touch the wheel. It is advisable
to keep the rock against the disc by the aid of the thumb of
the left hand so as to prevent it from jumping. The edge of
the disc must be kept well supplied with the carboriui(luui and
water, as the cutting is then nnich expedited.

When one piece is cut off, the rock is lifted free of the disc,
and is moved forward by the spindle ready for the next slice
to be cut.

Having obtained a suitable piece, either by chipping or
cutting, the next thing to be done is to make one side of it
perfectly plane and smooth. This can be done by rubbing the
rock on a piece of plate glass, say, six to eight inches square,
which is moistened with carborundum and water. A zinc or
copper plate can be used instead of the .glass, but I have found
the glass to cut better and work more quickly. I use the same
grade of carborundum for this as I do for slitting, as I find
No. 150 is not coarse enough to tear the rock or fine enough
to make the work tedious. Coarser grades can, of course,
be used, if thought desirable, but it is not advisable to use
anything coarser than No. 90.

With the machine described in the January luunber the rough
grinding is done on the lap. I usually make the lap revolve
in the opposite direction to the hands of a watch, and hold the
rock in the fingers of the left hand against the left side of the
lap, so that I push against the revolution of the wheel. This
I have found easier than pulling against the wheel. It must
be borne in mind that the periphery of the wheel cuts faster
than the inner portions, and the section, therefore, must be
fretiuenth twisted and moved backward and forward from the
edge of the wheel to the centre so as to keep a plane surface.

When a perfectly flat surface has been procured, the rock
must be rubbed by hand on a sheet of glass with finer
carborundum, say No. FF, so as to remove all coarse scratches.
Care must be taken at this stage not to get any coarse powder
on to the glass plate, or it will cause bad scratches on the rock.
The latter can be finished off on FF emery cloth, which is
supported on a glass plate, and it is then polished on a piece
of worn emery cloth. No, 0. It is not necessary to get a
high polish with ordinary igneous rock, so long as there are no
scratches.

The next process is to fasten the piece of rock to a suitable
handle for the grinding of the reverse side. It is customary
to employ pieces of plate glass for this purpose, and those I
use are one-and-a-half inches square. Various cements are used
for fixing the rock, the one generally adopted being ordinary
hard Canada balsam, although a better one can be made of
Venice turpentine and commercial shellac (bleached), which
can be procured at any ordinary paint and varnish shop. The
proper proportion is about three of Venice turpentine to one
of shellac. The turpentine is melted in a water bath, and the
shellac is then stirred in, a little at a time, until it is thoroughly
incorporated. Test the cement by dropping a little on a cold
glass plate, and if it dries practically at once into a hard glassy
bead, it is all right. If it is greasy-looking it needs more
shellac, and if it is too brittle and chips, more turpentine must be
added. When it is of the right consistency, it is poured out
on a glass plate, and rolled into sticks like sealing wax, ready
for use.

To cement the rock to the glass, put the latter on a hot
plate over a spirit lamp and place a small portion of the
cementing material in the centre. At the same time lay the
rock on the hot plate to warm. When the cement melts and
runs, pick up the rock in a pair of forceps and place it in the
centre of the cement. Press down hard to squeeze out the
excess of cement, taking care that no bubbles remain between
the rock and the glass. If there are any, the rock must be
melted off and the work started again. When the rock is
cemented satisfactorily the glass plate is put away to get cold,
say. for about an hour. Take care when heating the cement not
to make it too hot so that it smokes, as this dri\es oft" too
much of the turpentine and makes it brittle.

.■\ method that I have found very satisfactory for fastening
the rock to the plate glass holders is to use gum arable, made
into a thick solution about the consistency of treacle. .A drop
of this is put in the centre of the glass, the rock is placed in
position and the excess squeezed out gently with a slight
twisting motion. This will dry in about twenty-four hours and
the rock can then be ground down in the usual wa\'.

Having securely fixed the rock to the glass plate, the next
step is to grind it down siifficiently thin. If the work is being
done entirely bv hand, and the rock has been cemented to the

February. 1911.

KNOWLEDGE.

75

if

glass with balsam or shellac, it should now be nibbed on the
glass plate until the section becomes translucent. During this
operation the plate must be well supplied with a paste of
carborundum powder and water, using plenty of water. The
rubbing is done with a circular motion, and it is advis.ible to
make the circles as small as possible, as then there is then less
tendency to bevel the edges of the section. Care should be
taken also to do the rubbing over the entire surface of the
plate, so that it wears evenly.

If, on the other hand, the rock has been fastened on with
gum arable, the rough grinding by hand must be done on the
glass plate with dry carborundum powder or otherwise the
water will cause the rock to leave the glass. The rough work
is done so ([uickly, however, with the grinding lap on the
machine, that it can be used
whether the rock is cemented
with shellac or gum arable,
as the grinding is so rapid
that the gum has no time to
dissolve. When doing the
rough grinding on the lap,
great care must be taken that
the section is ground evenly
on all sides, and that the
operation is not carried on
too long, because the lap is
revolving so rapidly that in a
few seconds the whole of the
rock may be removed from
the glass.

It is diflficult to give
directions as to how long
this grinding with the coarse
powder should be continued,
as it depends, in a great
measure, upon the rock itself,
but a little practical experi-
ence will soon decide this for
the operator. A rough-and-
ready rule is to stop when
the rock shows signs of
chipping off at the edges.

It should then be transferred
to the other glass plate, with
finer carborundum, and the grinding continued by hand until
the rock is sufficiently thin. Great care nuist be taken in
these later stages, and the rock must be examined under the
microscope from time to time to see if it is thin enough. The
final rubbing must be done on Water-of-Ayr stone, or one of
the very fine carborundum stones used for razor sharpening.

\\'hen the rock is fixed with gum arable, the final grinding,
after the use of the lap, is done on a glass plate with FF
carborundum used dry, finished off on FF emery cloth, and
polished on No. O emery cloth. As mentioned previously, it is
not necessary to get a high polish, and any small scratches are
practically unnoticeable when the section is mounted in balsam.

The next operation is to remove the section from the glass
holder. If it is cemented with balsam or shellac, it should
be placed in ordinary commercial methylated spirit, and must
remain out of reach of dust until it has left the glass. This
usually takes some time, but it must not be assisted in anyway
by pushing the section with a brush or needle, as this is almost
certain to destroy it.

If it is stuck on with gum. it is simply put in water and
usually lea\es the glass in about an hour. In either case
after the rock has left the glass, it is rinsed in clean methylated
spirit, and is then ready for mounting.

When moving the sections from one receptacle to another I
always use large section lifters about one-and-a-half inches by
one inch. These I cut out of thin sheet brass with a pair of
scissors. They have practically no handle, and will, therefore,
stand where they are placed without falling backwards. I find
these very useful when placing sections in the final methylated
spirit, as lifter and section are put in the receptacle together.

The mounting is done in the ordinary way in balsam and
benzole. The most difficult part is the transference of the

\

,^

Figure 1.
Ovipositor and Egg of Hydrachna gcograpJiica X 56.

section from the lifter to the glass slip. The section when
taken from the spirit is pushed with a sable brush carefully
over the edge of the lifter until it projects as far as is safe, and
is then picked up on the hairs of the brush, and transferred to
a heated slide. The heat of the slide soon evaporates the
spirit, and then a drop of balsam can be applied to the ed^e of
the section, under which it will be drawn. .Arrange the section
in position on the slip with a needle, examine under the
microscope with polarized' fight to see there are no bits of
fluff or other forei.i,n substance, put a drop of balsam on the
section and then the cover glass. C. H. C.\f.fyn.

NOTE OX HYDRACHNA GEOGRAPHICA MULL.
— In May last. .Mr. Braithwaite found a female Hydrachna

gcograpliica Miill, in Epping
Forest. This mite is the
X largest of all the known water

/ mites. The female often

measures as much as eight
millimeters long in the body.
Mr. Braithwaite, hearing 1
was in want of a full>-
developed female of this
species, kindly sent it on to
me. After I had draw'n and
measured the mite I dissected
out the epimera and genital
area, and mounted that part
in balsam for future reference
and for comparison with
other species of the same
genus. I did not know
before, but while I was ex-
amining it during mounting I
found the o\ipositor was fully
extended and that an egg was
in the act of leaving the tube,
and I am pleased to say this
position has been retained,
even now it is permanently
mounted in balsam. I have
mounted hundreds of genital
areas of water mites, but
never had the good fortune
to find one like this before, and I do not expect to
ever find another. I mounted it without pressure,
placing the cover glass on the liquid balsam and allow-
ing it to settle down by its own weight. No doubt the
slightest pressure would have squeezed the egg out of its
position. The length of the genital plates with the ovipositor
is 1-04 mm., length of egg 0-24 mm. The drawing was made
under the camera-lucida, with one-inch objective. It shows
the exact position of the genital area, and its position between
the third and fourth pair of epimera. The female was full of
ova. but the eggs in the body were spherical, so the oval form
taken by the egg shown in the figure is no doubt due to it
being squeezed through the ovipositor.

Ch.\s. D. So.\r. F.R.M.S.

THE DIVISION OF THE COLLAR-CELLS
IN CLATHRIXA CORIACEA.— In the \o\embernmnber
of the Quarterly Journal of Microscopical Science (Vol. 55,
p. 611) a contribution is made under the above title, by Miss
M. Robertson and Professor E. A. Minchin, to the theory of
the centrosome and blepharoplast. It is now generally
admitted that these bodies are of essentially the same nature.
The centrosome may be briefly characterised as a bod\' which
e.xerts or governs kinetic functions in relation to division of
the nucleus, while the latter, or blepharoplast, may be defined
as a centrosome which governs motile organs, such as flagella,
which arise from it. and are in more or less direct connexion
with it. The results are briefly simimarised by the authors at
the end of the paper. The nucleus of the collar-cell migrates
from the base to the apex of the cell, and so comes to he
immediately under the blepharoplast. The flagellum dis-
appears, and the blepharoplast di\ ides. The two daughter-

76

KNOWLEDGE.

February, 1910.

blepharoplasts now travel to opposite sides of the nucleus, and
take on the function of centrosonies. The nucleus breaks np
into chromosomes, its membrane disappears, a mitotic spindle
is formed in the nsual way, with t!ie two centrosomes at its
poles. The two new flagella then at once begin to grow out
from the two centrosomes, outside the original collar and
before the equatorial plate is divided. The mitosis is com-
pleted, and as the cell-body divides, the original collar breaks
down and disappears. The centrosomes become the blepharo-
plasts of the two dausjl'ter-cells, the flagella continue to gnjw
out from them, the n^-w collars grow up round the new flagella,
the daughter-nuclei return to the bases of the cells, and the
two daughter-cells resume the structure and appearance of
the ordinary resting collar-cell. It is thus seen that the
blepharoplast-centrosome is a permanent cell-organ which
divides with the cell, while the collar and flagellum are formed
afresh at each cell-division.

ORNITHOLOGY.

By Hugh Boyd Watt, M.B.O.U.

THE BOYD ALE.XANDER COLLECTIONS.— The very
fine and extensive collections of bird-skins made by the late
Lieutenant Boyd Alexander, in the course of his scientific
journeys in Africa, are to go to enrich the national collections
at the Natural History Museum, South Kensington. Lieutenant
Alexander, who, it will be remembered, was killed in the
course of explorations in Africa last year, died intestate,
but, in accordance with his wish, the Museum above-
named is to have his collections. These are housed at present
in a private museum, which was specially built for them
at Wilsley. The collections are from wide areas in Central
Africa, visited since 1897, including the Cape Verde Islands.
Zambesi River, Kumassi, Fernando Po, and the great regions
travelled through from 1904 to 1907, described in Lieutenant
.iXlexander's book, entitled "From the Niger to the Nile," also
from the islands of San Thome, Principe and Annabon, and
Cameroon. Lieutenant Alexander obtained many species new to
ornithology and science, and described (and in some cases figured )
them in the pages of the Ibis, and of theBiillctiii of the British
Ornithologists' Club. In a comparatively short life, devotion
to his favourite pursuit yielded a rich harvest, and the memory
of this intrepid traveller and ornithologist will be further
perpetuated by this splendid gift to the nation and to science.

MIGRATION. — It is good news to ornithologists that
Mr. William Eagle Clarke, of the Royal Scottish Museum,
Edinburgh, is .ibout to publish a work dealing with the
study of bird-migration in the British Isles. It is not too
much to say that, despite much writing (or, perhaps, because
of it) knowledge lingers here, still in the obscurity of
conjectures and surmises, and the time is ripe to attempt an
advance on a genuine scientific basis. From no one is new
and clear light more likely to come than from Mr. Clarke, who
has devoted many years, dating back to the days of the
Migration Connnittee of the British Association, to the stud\-
and accumulation of facts and observations. Besides having
at his command the long series of reports made year after
year by many observers and recorders throughout the country,
Mr. Clarke has, within recent years, spent lengthened periods
at the migration seasons in outlying localities from the
Eddystone Rock in the south to the remote islands in
the north, on the fly-lines, or routes of migrants. Readers of
his preliminary reports and notices know that he has gathered
abundant and rich results. A mere enumeration of species
does not in itself throw light on migration problems, still it
is notable that the small Fair Isle (between Orkney and
Shetland), has yielded records of no less than one hundred
and ninety eight species of bird visitors, including man\'
which experienced ornithologists have never seen in Britain.
For instance, the year 1910 gave three species new to the
faunaof Scotland, viz., the Hoary Redpoll (Acanthis exilipcs).
Holboll's Redpoll {A. linaria holboclli) — a second example
occurred on the Isle of May, October 2Jrd — and the
Yellowshank (Totanus flavipes). (Ann. Scot. Nat. Hist..
January, 1911, page .S3).

A NEW BRITISH BIRD.— Amongst the birds observed
and procured by Mr. Wm. Eagle Clarke at St. Kilda — the
furthest west and most remote of the British Isles — last autunm
(1910), was the American Pipit iAntlius pcnsylvanicus). new
to the British fauna, and the Marsh Warbler (Acroccphalus
pahistris), new to Scotland. (.4;;//. Sco^. Wat. Hist.. JSLnu3.iy
1911, page 52). The rarity of the Pipit named is so great that
the only mention of it to be found in Dresser's " Manual of
Palaeartic Birds" (1902) is a statement that it so nearly
resembles A. spipoh'tta as to have been included, in error,
as a European bird.

A PROPOSED CENSUS OF TUK COMMON HERON
(Ardea cinerea). — Such a bird as this, large in size and
sedentary in habits, affords the possibility of some success
attending an attempt to number the individuals in a limited
area. A proposal is being mooted to undertake this enumera-
tion in Scotland, where the location of the Heronries, which
are widely distributed over the mainland, is pretty accurately
known at present. This wide distribution may, however, prove
a serious difficulty in the attainment of accuracy or complete-
ness of returns. The numbers of several species of British
birds are known, but these are mostly inhabitants of restricted
areas or individually scarce, or where the species may be called
common, e.g.. the Gannet, its occurrence is concentrated (at
any rate at the breeding season) at a few well-known stations.

PHOTOGRAPHY.

By C. E. Kenneth Mees, D.Sc.

THE MICROSCOPIC STUDY OF DRY PLATES.—
Dr. W. Scheffer, of the University of Berlin, in his lecture at
the Royal Photographic Society on December 20th, described
the investig.ations which he has made on the effect of exposure
and development upon the individual grains of a gelatino-
bromide emulsion. He has designed for his work a very
complete experimental equipment, and his photographs are
all taken at a magnification of two thousand diameters,
much higher than has been used by previous workers in the
subject. Photographs taken of grains during the process of
development show that the grains are of two kinds, which
Dr. Scheffer distinguishes as " original grains " and " nourishing
grains." The original grains have filaments projected from
them, either during exposure or at the commencement of
development, and Dr. Scheffer concludes, from his later
observations, that grains showing these filaments remain
unaltered during the progress of development, and become
covered by the metallic silver which is deposited upon them,
this metallic silver being derived from the solution of the
'■ nourishing grains," which disappear during development.
When a plate is under-exposed there are few original grains
present, and with o\er-exposure many original grains and few
nourishing grains, a fact to which Dr. Scheft'er ascribes " the
lack of density produced by over-exposure." This seems to
require re-consideration, because ordinary over-exposure does
not produce lack of density; the thinness which most amateurs
assign to over-exposure is due to under-development ; if an
over-exposed plate be developed for the normal time, it will be
extremely dense all over. Possibly, however, Dr. Scheffer
intended the reversal period by "over-exposure." The con-
nection of these observations with the known facts as to the
chemical dynamics of development will require a great deal of
work. It is not at all obvious, for instance, that a steady growth
of original grains and diminution of nourishing grains would
be in harmony with Hurler's " Law of the Constancy of
Density Ratios," which is the photographic equivalent of the
mass-law.

Moreover, the statement that there are silver bromide grains
in the film of a plate which are unaltered in development and
which can survive fixation, should be capable of confirmation
by chemical experiments on plates in the mass, and the amount
of such grains should be readily ascertainable if developed
and fixed plates are treated with a solvent of silver which is
incapable of affecting silver bromide. Dr. Scheffer showed an
experiment in which this was done, but this would require con-
firmation by quantitative megisurement on masses of developed

Fkbkuarv. 1911.

KNOWLEDGE.

77

film sufficient for the purposes of ordinary chemical analysis.

If the quantity of these unattackable grains varies with the
exposure it would seem probable that the amount of metallic
silver required to produce a given light absorption would vary
with the exposure also, and it is known that such variation
nmst be very small if it occurs at all.

A most interesting experiment of Dr. Scheffer's would seem
to suggest that the " filaments " can scarcely be produced
during exposure. A small quantity of emulsion was placed on
a slide and a most powerful beam of light passed through it
by a Zeiss projection apparatus and microscope, the image
being projected on to a screen.

Under these conditions the grains could actually be
observed to decompose under the action of light, shooting out
the " filaments " or clouds of nebulous matter, and going black
with growths, apparently of metallic siher, upon them. The
amount of light required to produce this effect is very great,
however, and there seems to be every reason for doubt as to
whether an\- actual decomposition of the grain is produced by
ordinary exposures.

Dr. Schefter also described the investigations which he had
made as to the distribution of the image in the film of the
ordinary dry plate. The great difficulty in such work is the
preparation of sufficiently thin sections, since for first-class
results the sections should not be thicker than i m (^cnuth mm).
By the aid of a special microtome of his own construction.
Dr. Scheffer has been able to attain to most excellent results.
and one photograph, showing not only the Zenker's laminae in
a Lippmann plate, but the actual grains composing them, was
a marvellous testimony to the perfection of Dr. Schefter's
methods.

Most of the results obtained from sections confirm those of
previous investigators, but the studies of the action of various
" reducers " are of special interest, and make very clear the
known differences between the various oxidising agents
employed to reduce the density of photographic negatives.

DEVELOPMENT WITH HVDROOUINONE. — The

chemical reactions involved in development are generally
complicated, and the oxidation products of the organic
developers are especially obscure.

One of the simplest of the organic developers is, of course,
hydroquinone, which is oxidised to quinone by silver bromide.

Using the ordinary nomenclature, the reaction will be

CnH4(OHI.. + 2AgBr+2NaOH^C„H<Oo + 2.Ag +
2NaBr+2HoO,

one molecule of hydroquinone producing two atoms of silver.

It has been shown that this reaction is reversible, quinone
and soluble bromide having the power to oxidise a silver
image to silver bromide. So that quinone and a soluble
bromide will act as a photographic reducer lof density) as has
recently been pointed out by MM. Lumiere and Se\'ewetz.

But the simple equation given above does not by any means
express the whole of the reactions taking place in a hydro-
quinone developer containing alkali and sulphate.

Quinone reacts with sulphite, oxidising it to Dithionate and
being reduced to Hydroquinone thus : —

Na2SO:^ + C,iH40.2+2H.O = Na.>SoO„-|-2NaOH + C,iH4(OH).,

Moreo\er, the addition of an alkali to quinone reduces some
of it to hydroquinone, apparently being oxidised to peroxide,
since the ether extract gives the characteristic blue colour
with acid bichromates. So that both the sulphite and the alkali
regenerate the reducing agent from its oxidation product, and
the development reaction becomes far more complicated than
would at first appear.

PHYSICS.

By \V. D. Eggar, M.A.

\\'.-\VES \'ERSi'S K.WS. — A good many years ago
Professor C. V. Boys took a series of photographs of flying
bullets. In these a prominent feature was the wave from the
bow of the bullet, as from the bow of a steamer. It was a

wave of compressed air, made instantaneously visible to the
eye of the camera by the spark which took the photograph.
In fact, it was a wa\e of sound. Following up this discovery,
Professor R. W. Wood took a series of photographs of sound
waves, issuing from a central point. The sound was that of
an electric spark, and the photograph.^ were taken by the light
of another spark, following close upon the heels of the noisy
spark. The interval between the two sparks could not be
regulated with any accuracy, but a large number of photo-
graphs were taken, which are pubhshed in the form of lantern
slides, and appear also in Wood's " Physical Optics." Thej'
illustrate many of the main features of wave-motion, and are
exceedingly useful in explaining the wave-theory of light. In
a paper read to the Physical Society on "Cusped Waves of
Light and the Theory of the Rainbow," Mr. W. B. Morton
alludes to the tendency at the present time to ba:e the
teaching of Optics on the conception of the wave, rather than
that of the ray. This tendency was further exemplified at the
annual meeting of the Public School Science Masters' Associa-
tion, at which Mr. J. Talbot gave a demonstration of his use of
the ripple-tank. This is a large flat glass tank with water in it
to a depth of about half an inch. It is supported at the
height of an ordinary table above the ground on which is
placed an arc light, screened from the class. A translucent
screen tilted above the tank on the side of the class recei\es
the shadows of the ripples made in the surface of the water.
The velocity of the ripples can be altered by altering the
depth of the water, and this can be done by flat glass plates.
Hence, many of the features of reflection and refraction can
be demonstrated by the medium of surface ripples. The
method forms a most useful addition to the equipment of a
teacher of Optics. At the same meeting, Mr. C. F. Mott
exhibited his apparatus for teaching Optics by the method of
rays. In place of the usual pins employed in elementary
practical Optics, Mr. Mott uses a beam of light coming through
a pair of narrow slits, fixed at the ends of a groove cut in a
block of wood. The conception of rays is, in the opinion of
some, the natural introduction to the subject, and if it be right
to follow historical order in the presentation of physical
knowledge, rays would undoubtedly come before waves.
However, as the protagonists agreed, the two methods are
supplementary rather than antagonistic ; and it must be borne
in mind that the teacher of science has sometimes as his aim
the stimulation of interest in physical phenomena, at other
times the training of the youthful mind in methods of precision.

THE RADIO-BALANCE.— In the December number of
the Proceedings of the Physical Society there is an important
paper by Professor Callendar describing his radio-balance.
This instrument is devised for the absolute measurement of
the heat of radiation, and is specially applicable for that of
Radium and its emanation. The heat imparted by radiation
to a small copper disc or cup is directly compensated by the
heat absorption due to a Peltier effect created in an iron-
constantan thermo-couple connected to the disc, and to a
variable source of electric current. The Peltier co-efficient
and the value of the compensating current being accurately
determined, the heat of radiation can be measured with
considerable accuracy, when an exact balance between the two
effects is obtained.

ZOOLOGY.

By Professor J. Arthur Thomson.

NON-DIGESTIBILITY OF FAT BY PROTOZOA.—
W. Staniewicz calls attention to a curious point, that the
Protozoa have never learned to digest fat. .All Metazoa have
this power, but Protozoa have not. Experiments with Para-
moecium, Stentor, and some other common Infusorians show
that fat may be ingested, but it is not digested. It is not a
natural part of a Protozoon's food. The fat sometimes found
in natural conditions within the cell of a Protozoon seems to
be due to the transformation of proteids or carbohydrates.

MUDDY TASTE IN FRESHWATER FISHES.— It is
well known that carp and tench and eels and some other
freshwater fishes are apt to be tainted with a peculiarly

78

KNOWLEDGE.

Feuruarv. 1911.

disagreeable taste, which sometimes makes them almost
uneatable. The taste is called "' iiiuddj'," but Louis Leger's
experiments have shown that it is not directly due to the mud.
The Stonewort 'iChara), which has a curious odour, has
been blamed, but Leger has shown that the "muddy" taste
may occur in fishes from basins without any stonewort.
Following the method of excUision. he has traced the mischief
to Oscillarias, those curious mobile Algae, which are common
in fresh waters. They are directly or indirecth' used by the
fishes as food, and it is their " essence " that saturates through
the fish-body. The taste is strongest in the glandular parts of
tbe sUin and in the kidneys. Carnivorous fishes are less liable
to be tainted, but even trout do not escape.

A NEW CO>r'>iEN"SAL TURBELLARIAX. — Professor
Edwin Lin'"- ;,'and in the ribbed mussel {Modiolus
plicatiilii .: A'oods Hole an abundant occurrence of a
comment. i 'i ^ele Turbellarian, belonging to the genus

GraiplJi\ ' .1 ' losely-relaled genus. It is interesting in

many ways, e.g., in containing ciliated young, most of which
were in t'm'os inside a thin capsular envelope. The young are
not liberated until the reproductive powers of the mother are
exhausted, when they make their way through the ruptured
body-wall. Another interesting peculiarity is that the adults,
which rarely reach 2mm. in length, move by a series of zi.g-zags,
— a mode of progression which affords constant change of
position within the limited area of the host.

DO BLOW-FLY LARVAE RESPOND TO GRAVITY?—
S. O. Mast has investigated Professor Jacques Loeb's statement
that blow-fly larvae " when placed under the surface of the
water, do not swim upwards and so avoid death, but swim
downwards." It is found, however, that blow-fly larvae do
not react to gravity, either in water or out of it. In air they
may be found to crawl nearly straight upwards on objects, but
experiments show that this has no relation to gravity. In
water they sink to the bottom or float at the top according to
the amount of gas they contain, and there is no evidence
whatever indicating that they can swim.

PROCESSION CATERPILLARS.— A month or two ago
we described observations on the habits of the Procession
Caterpillar. Cncthocampns pinivora, made at Arcachon by
Mr. T. G. Edwards in the Spring of 1909. An account of
additional observations and experiments made in the following
Spring is now published by Mr. H. H. Brindley. Strangely
enough, the greater number of the processions seen by
-Mr. Brindley were met, not within the forest itself, but on a
broad road (over which there was constant traffic) leading
towards it. The road was bordered by \illas, in many of the
gardens of which there were pine trees. Many nests containing
living larvae were found on the young pine saplings in the
forest, and in all cases the branches near the nest were thickly
matted with the threads secreted by the larvae. Very few
threads were found on the branches at a lower level, or on
the trunk, and of these none reached the ground, so that the
threads gave no evidence that the larvae were in the habit of
leaving the nest and returning to it. A series of experiments
with the thread showed that it has no great importance in
the formation of the procession, or even in keeping it together.
Head to tail contact seems the important factor, and when
that is broken, the detached portion of the procession joins on
again, apparently by sight, if the distance is not great.
The thread forms the nest in the tree, and the cocoon in the
pupa state, but it is not clear why it should continue to be
formed when the larva is away from the nest, unless it is to be
regarded as a mere secretion. Mr. Brindley made an interest-
ing series of experiments to test the permanency of the
leadership. In small processions, each individual caterpillar
was dusted with a powder of a different colour, and the pro-
cession was interrupted. In fifty per cent, of cases the same
leader took the head of the procession, whether mass-formation
was natural or artificial ; the leader for the time being
undoubtedly determining the behaviour of the procession, since
contact is always maintained. The leader always takes the
initiative in mass-formation and very frequently in burrowing.

The observer did not experience any irritation on handling
the caterpillars, and he believes, with his collaborator, that the

degree of sensibility to the glandular hairs \aries with the
individual.

YAWNING IN FISHES.— Mr. Richard Elmhirst.
Superintendent of the Millport Marine Biological Station, has
made some \ery interesting observations on Yawning in Fishes.
He has watched it in cod, saithe. cobbler, plaice, and some
others. He describes the wide opening of the mouth, the slow
expansion of the buccal cavity, the erection of the gill-arches,
and then a rapid expulsion of the indrawn water, mostly from
the mouth, partly through the gill-slits. This is often
accompanied by a distinct heaving of the pectoral region and
erection of the pectoral fins, and is quite different from the
rapid movement of the gill-cover and jaws when the fish
dislodges a bit of seaweed from its gills. " From numerous
observations, I am led to think that this action of fishes is a
real yawn, and serves the true ph\-siological purpose of a
yawn, i.e., flushing the brain with blood during periods of
sluggishness. The conditions conducive to yawning are a
slight increase in the temperature of the water, and. I suppose,
the accompanying dimhmtion of oxygen."

A NEW KIND OF SENSE ORGAN.— As anatomical
analysis becomes more and more minute there is a continual
discovery of new intricacies. A good illustration is to be
found in an investigation which Dr. K. W. Dammermaun has
recently been engaged in, concerning the saccus vasculosus. a
dependence of the brain peculiar to fishes. It will be
remembered that there is a remarkable downgrowth, or
infundibulum. from the tween-brain or region of the optic
thalami (the part of the brain that also gives origin to the
pineal body as a dorsal upgrowth 1. This infundibulum bears
the very interesting pituitary body, but it also gives off a
posterior diverticulum called the saccus vasculosus. In many
fishes this extends backwards and lies, along with the pituitary
body, in a pit of the skull called the sella turcica. It has been
usually regarded as a glandular structure, but Dammermann
has proved up to the hilt, what a few have suspected, that it is
a sensory organ with somewhat striking sense-cells. In an
ingenious argument he suggests that it may enable the fish to
test the degree of oxygenation in the water, and thus to seek
out the depth physiologically most comfortable. He proposes
to call it a " Benthic " or Depth-Organ.

EVOLUTION OF REPTILIAN ARMATURE.- Georg
Stehli has been studying the development of scales (in the wide
sense) in various reptiles, and comparing recent with extinct
forms. He is strongly of the view, also held by Hase and
Otto, that the scales had primitively a segmental arrangement,
and that each horny scale belonged primitively to an under-
lying bony scale. His theory is that the evolution of reptilian
armour has passed through four stages. First, there was the
primitive stage (which must, of course, have had a long evolution
behind it) of strictly segmental arrangement of horny scales
with bony scales beneath them. In some cases doubling gave
rise to two rings of scales for each segment. Secondly, the
bony scale broke up into a mosaic of little plates, as seen
to-day in Scincoid lizards. Thirdly, the bony scale disappeared.
Fourthly, the horny scales multiplied and lost their segmental
arrangement.

A QUAINT STRUCTURAL ANALOGY.- One might
spend a pleasant life-time in admiring organic adaptations.
One of the last we have read about concerns the "snow-shoes"
of the North-American ruffed grouse (Bonasa iDiihcUata).
According to Dr. Austin Hobart Clark, these " snow-shoes "
de\ elop in winter as two rows of '' scutes " on each side of
each toe. and they increase the area of the foot by as much
again. Thus the bird treads safely on the lightly-compacted
snow. It might be interesting to test experimentally whether
the stimulus of wet feet at some other season than winter
would induce the extra integumentary growth. Dr. Clark
points out that a figure of the ruffed grouse's toe is very much
the same as a figure of the arm of some of the Crinoids from
deeper waters. Two rows of supplementary plates occur on
each side of the median row, and the meaning of the adapta-
tion is to increase the receptive surface on which the shower
of minute dead organisms is caught. Convergent adaptation
in two creatures ahnost literally as far as the poles apart !

February, 1910.

KNOWLEDGE.

79

HAD CETACEANS A TWOFOLD ORIGIN ?— It has
been repeatedly suggested that the toothed whales are not very
nearly related to the baleen whales, and Professor Kiikenthal,
in particular, has argued in support of a " diphyletic origin."
Dr. Stefan Sterling, a worUer in Kiikenthal's Institute, has
recently gone carefully into the musculature of the fore-limb,
and finds that in respect to this the toothed whales and baleen
whales are not very closely related. Their resemblance is

one of convergence ; that is to say, the flippers are independent
adaptations to similar conditions. The toothed whales diverge
further from the typical Mammal and must have had an
earlier origin than the baleen whales. Thus anatomy
illumines evolution. It is interesting to note that the flipper
type of limb nuist have been evolved several times independ-
ently,— in Ichthyosaurs, in post-Triassic Plesiosaurs, in
Cetacea (twice ?), in Sirenia, and in Pinnipedia.

RE\'IE\VS.

AERONAUTICS.

Tlu- Problem of Fliglit. — B>' Herbert Chatley. B.Sc.
IJl pages. 60 illustrations. 9-in. X 6-in.

(Charles Griffin & Co. Price 10 5 net. I

This book, which bears the somewhat ambitious title of a
" Textbook of .Aerial Engineering," is not one which it is easy
to review. The first edition was written some months before
Farman, in January, 1908, succeeded in making the first
circular kilometre flight in Europe. Owing to the author's
absence in China, the present edition is admittedly not up to
date, although numerous alterations and additions ha\e been
made to the text, and some of the original rather crude
illustrations have now been replaced by more accurate photo-
graphic reproductions of various aeroplanes.

There is, however, no mention of the well-known Farman or
Bleriot machines, nor does the victorious Gnome engine recei\e
any mention, and none of the recent work of the English
constructors is described.

On the other hand this edition is not much blemished b\-
misprints, though there are a few minor errois, such as on
page 48b " Driwiski " for " Drzewiecki," and " V'oison " for
" Voisin."

Chapter I. deals with general considerations; Chapter II.
with essential principles. In Chapter III. when discussing
propellers, the author states (in effect) that the total projected
blade area should approach very nearly to the disc area,
provided the blades are not sufficiently near to cause inter-
ference ; this does not seem to be very conclusive.

In Chapter IV. three methods of starting aeroplanes are
gi\en. but no reference is made to the Wright Bros.' pylon
and falling weight device.

Chapter V. on '" Ornithopters," is good, but does not
command much interest at the present time ; the author
seems to have a particular penchant for the Helicopter, and
devotes a good deal of space to this type throughout the book.

In Chapter VII. on "Form and Fittings of .'Verial Vessels,"
the author states that "corrugated aluminium for helices and
aeroplanes has been foimd to be very efficient," though it has
not been used by any successful machine at the present date.

Some of the appendices are interesting, and are perhaps the
most valuable portion of this book. In appendix H. the
author discusses landing problems, but apparently has some
idea that the aeroplane always meets the ground at its gliding
angle ; the operation of the " vol plane " docs not seem known
to him.

The bibliography at the end is not at all complete, nor is
the list of aeronautical societies and clubs up to date. On the
whole, however, the book gives plenty of food for thought, but
the author endeavours to co\er too much groimd, and has a
fatal tendency to indulge in mathematical jerry-building ;
edifices of most elaborate formulae are piled up on (in many
cases) extremely slender foundations, and, as a result, are
naturally neither of a permanent nor useful character.

There is no doubt that Mr. Chatley is an able mathe-
matician, and if he will only alloy his theories with a greater
number of practical facts, he may then succeed in producing
something of value to the aeronautical engineer.

CHEMISTRY.

Spark Spectra of flic Mcfals.— By C. E. Gl.SSiNG, F.R.G.S.
21 +vii. pages. 10 plates. lU-in. X Sj-in.

(London: Bailliere. Price 7/6 net.)

The method of spectrum analysis is now so widely used to
ascertain the composition of unknown bodies that this book of
Admiral Gissing, which embodies an enormous amount of
work, should be welcomed in many directions. It gives a brief
description of the prism spectroscope and of the methods of
obtaining spark spectra and recording them by photography,
but its chief value will be as a work of reference. For since
it gives photographic enlargements of the spectra of fifty
different metals, alloys and gases, it will be a simple matter to
ascertain, by comparison of the spectra and measurement of
the wave lengths of the lines, the constituents of any mineral
or mineral ore under examination. The photographs are
excellently reproduced and notes are given to call attention to
the most characteristic lines in each case.

Ciiiiilirulgc County Gcoiirapliics — Fifcsliirc. — By E. S.

Valentine, M.A. 187 pages. 64 illustrations. 4 Maps.

73-in. X5.i-in.

(Cambridge University Press. Price 1 6 net. I

The Scottish series of Cambridge County Geographies, so
admirably begun with the volume on Lanarkshire, is well
continued in the little book under review. By virtue of its
position, the ancient kingdom of Fife — a peninsula jutting into
the North Sea between the Firths of Tay and Forth, and
separated from the rest of Scotland by the Ochil Hills, lends
itself specially to treatment as a geographical unit. The
uniciue geological phenomena found along its shores, its
ancient history, its abundant mineral resources, and last, but
not least, its claim to possess the Mecca of golfers, give Fife-
shire special prominence amongst Scottish counties. Whilst
largely an agricultural county, weaving, fishing, and mining
particularly, employ a large proportion of its inhabitants.
Dunfermline is the chief seat of table-linen manufacture in
the world, and Kirkcaldy is almost equally famous for
floorcloth and linoleum. Coal-mining has so progressed of
late years that Fifeshire, from the third in 1899, had sprung to
the first place among Scottish counties in 1906, in the quantity
of coal shipped from its ports. In style, get-np and readability
this book upholds the high character of this series : and Mr.
\'alentine has worthily maintained the standard set up by the
initial volume on Lanarkshire.

An Elementary Treatise on Co-ordinate Geometry of

Three Dimoisions. — By R. J. T. Bell. 355 pages.

9-in. X 6-in.

(Macuiillan & Co. Price 10 - net.)

The author is Lecturer in Mathematics at Glasgow University,
and has embodied in this book the course of his lectures in
solid geometry. .After preliminary matter the book deals
chiefly with the Conicoids, but contains also chapters on
Ruled Surfaces, Curvature, and Geodesies. It has copious

so

KNOWLEDGE.

February, 1911.

examples, and might therefore be used to supplement a course
of lectures ; but we do not think a student would find it an
easy introduction- to the subject. The author has not the
qualities of a good guide; he neither turns round to survey the
ground already covered, ncr .~t-'ps to point out the path by
which the chmb is to be coiiiinued. The different subjects
are not made complete in themselves, nor is the relative
importance of different theorems or methods suggested. For
instance, the Ellipsoid is introduced on page S3, but instead of
being treated with proper respect, the form of its surface is
dismissed with a reference to an example in small print on
page 9. The book is well printed, but we are disappomted at
the paucity of illustrations which, with geometrical methods,
might be used to reinforce the analytical reasoning which the
author alone allows ; the chapters on the sphere and cone
contain no figures at all, and a student will find no suggestions
for drawing a sphere or representing points on its surface.

GEOLOGY.

Tlic ]i itluini and the Ancastcr Gap. a Study of River

Action. — By F. M. Burton, F.G.S.. F.L.S. 31 pages.

4i-in.X7-in.

(London : — A. Brown & Sons. 1/- net.)

r/ie Winding Course of the River Wye.— By T. S. ELLIS.

10 pages. Sj-in. X 8o-in.

(Gloucester: — John Bellows. 1 ■ net.)

In Mr Burton's interesting booklet the theory of river origin
we owe to the genius of Professor W. M. Davis is applied
with signal success to the origin and history of the Witham and
adjacent rivers, as it was also applied in the author's earlier
brochure on the River Trent. The Witham is a remarkable
river, which, rising near Oakham, first flows northward past
Grantham to Lincoln, and then makes an abrupt turn to the
south-east, entering the Wash near Boston. Excluding the
very recent lower portion from Lincoln to Boston, Mr. Burton
divides the river into three parts, — a tributary stream from its
source to Grantham ; a relic of an original transverse river
(supposed to be the primeval Devon) from Grantham to
Barkston ; and again a tributary stream from Barkston to
Lincoln. The original stream, the Devon, flowing east, cut
out the Ancaster Gap, after which it was captured by the
Trent, bringing the modern Witham into existence. There
were several minor vicissitudes, well worked out by the author,
before the Witham assumed its actual present course. The
pamphlet would have been easier reading if a map illustrating
the history of the river system had been included. Mr. Ellis,
however, will have nothing of Professor Davis and consequent,
subsequent or obsequent streams. His theory of river

origin seems to be that of the evolution of principal channels
out of a network of streams occasioned by the original
irregularities of a land-surface newly arisen from the sea. He
finds illustrations of the process in the water-channels on a
gravelled or macadamized slope. The sinuosities of the Wye,
for instance, are regarded as relics of an original network of
channels. Mr. Ellis rejects the principle of stream capture, on
the ground that he is unable to conceive of a stream working
headwards and thus extending its valley backwards. He finds
special difficulty in the case of valleys with low flat divides
between streams falling in opposite directions, and beheves
that these valleys have always been excavated by the
continuous flow of a body of water in one direction. Whilst
some of these valleys may have been cut in this way as a stage
in the development of a river system, the divides may have
been smoothed by glaciers or by glacial lake overflows ; and it
must be remembered that low flat divides are characteristic of
mature and ancient topographies. The paper is illustrated by
a map of the Severn-Wye river system.

PHOTOGRAPHY.

Photography in Colours. — By George Lindsay Johnson,

M.A., M.D.,"b.S., F.R.C.S. 143 pages, whh 8 plates in

colour. 7i-in. X5-in.

(Ward & Co. Price 3/-.)

The author states that he has separated Colour Photography
from Photographic Optics when revising his work on the
latter subject, and we cannot but feel that the separation is an
advantage : there was. indeed, no reason for ever including
two sucli distinct subjects within the covers of one text-book.

The present volume is, on the w^hole, a considerable advance
on the treatment of the subject in the earlier work ; the author
has collected together the information which has been published
by other workers, and has appended his own opinions to their
conclusions.

This method occasionally leads to remarkable results, as
when a solution of " Xyline red " is stated to be a nearly pure
blue in colour ; but, on the whole, the book is free from serious
mistakes. On the screen plate processes of colour photo-
graphy the book is very complete, but the short chapter on
other processes is practically useless; it is far too scrappy and
brief in its treatment. Incidentally we do not think that
F. E. Ives ever claimed to have discovered "the principle of
three colours being used to reproduce all colours." Ives
invariably claims that the originator of the true theory of
colour photography was Clerk Maxwell. We note with regret
that the author prints his spectrum diagrams with the red to
the left.

NOTICE.S.

WEBSTER'S NEW INTERNATIONAL DICTIONARY.
— We have before us the details of the new dictionary which
Messrs. Bell & Sons are publishing. As a matter of fact it
is really a new work, for there are four hundred tliousand
references as against one hundred and seventy thousand in
the previous dictionary which bore the same name. Very
special attention has been given to the many new words which
science has introduced into our modern vocabulary. Although
there are two thousand seven hundred pages, and six
thousand illustrations, the whole of these are contained in one
volume, which is issued at a reasonable price. The dictionary
is likely to meet the requirements of many of our readers, who
can obtain all particulars on filling up and sending in the
special coupon to be found on page iii of this issue.

CATALOGUES. — Among the many catalogues whicli we
have received is one of lantern slides sent by Messrs. Flatters
and Garnett, and we would call special attention to the photo-
graphs illustrating British Plant Associations, by Mr. W. B.
Crump, whose ecological work is well known. CJf special
scientific interest also are the photomicrographs by Mr. W. T.
Haydon, illustrating the reproduction and development of
Pinus sylvestris.

As usual, the classified list of second-hand instruments
which Mr. C. Baker has for sale or hire, is useful

and exhaustive, seeing that it runs to eighty-two pages.
From Messrs. R. & J. Beck, Ltd., comes a special new
catalogue of physical apparatus. Among some of the more
important pieces are optical benches for the testing of
photographic lenses as well as those which are used for
spectacles. There are also some glass troughs of useful and
various shapes which can be adapted to many purposes.

A MICROSCOPIC EXHIBITION.— Messrs. Watson and
Sons, Ltd.. 313, High Holborn, have sent us particulars of an
Exhibition of Microscopic Objects which -they are holding to
enable microscopists to see for themselves the great diversity
of objects which they ofter.

In order that the whole of the contents of their cabinets
may be easily examined, different subjects are set out week
by week so as to be readily glanced at and subsequently
examined microscopically.

Two of these Exhibitions have already been held and the
current one from the 30th of January to the 8th of February,
is of Botanical Subjects. Fungi, Algae and so on.
Future dates and subjects are : —

F'ebruary 13th to 22nd, Geological and Entomological

Specimens, Objects for Polariscope.
February 22nd to March Sth, Mounted Pond Life, '
Marine and Zoological Specimens.

Knowledo;e.

With which is incorporated Hardwicke's Science Gossip, and the Illustrated Scientific News.

A Monthly Record of Science.

Conducted by Wilfred Mark Welih. F.L.S.. and E. S. Grew, M.A.

MARCH, 1011.

X-RAYS.

Bv REGINALD MORTON. .M.D.

iCunfiiiiicd truiu Vulinnc XXXlll, piigc 49y.)

Ix the course of an article in a previous number, the
development of some of the various i)arts that go to
make up a modern X-ray equipment was briefly
described ; of those' that remain to lie dealt with,
none have a greater importance than the interrupter,
or " break " as it is generally called. As its name
indicates, its function is to interrupt or break the
flow of current through the [)rimar\- coil of the
inductorium. A sudden
interruption is essential
for the working of the coil,
and the more sudden and
complete it is the better
is the discharge from the
coil. Up to the time
of Roentgen's discovery
breaks were of a simple
and not verv efficient
form; they were only useti
in circuit with batteries
of low voltage, and as the
induction coils were as a
rule small in size and giv-
ing short spark length they
answered well enough.

The demand for greater
discharges to excite
heavier and stronger tubes
soon tnade it evident that
the interrupter would have
to be moditied, especially
as it was desired to make
use of the comparatively
high pressure currents
from the street mains. The
platinum hammer break iiy the comtcsy o/
(see Figure 2) was one of Figure 1.

the first, and though it is seldom used now for
hea\\- work, and mostl\- on portable apparatus, in
its most modern form it can be made to give very
good results. It requires care in adjustment and
manipidatidU. luit is practically the only kind that
can he used in military ser\ice in the field.

.\ disad^•antage of this form is the flashing that
takes place' between the platinum points every time

the current is broken; this
is troublesome when it is
desired to make use of
the fluorescent screen in
a dark room.

It was found that when
the break \\ as so modified
that one of the points
was replaced by a dish of
mercur\-, the spark from
the coil was intensified.-
In one of the earliest types
a copper wire was made
to dip in and out of the
mercur}- by the action of a
small electric motor, and
a number of these are in
use, for X-ra\' treatment
especially. (See Figure 4.)
Following on this we
have the mercury jet
breaks, which were a great
improvement, in that they
gave a much higher rate of
interruption for the same
(|ualit\' of discharge from
the coil. In these a small
The Sanitas Ei<xt>k,ii Co. jct of mcrcury is made
\n .\-Kav Cabk-Testins' Outfit. to impinge upon a copper

SI

82

KNOWLEDGE.

March, 1911.

blade or blades. It is immaterial whether the jet
revolves or whether the copper teeth revolve around
the jet, the r&sult is the same. The mechanism is
enclosed in a glass or iron vessel, which contains a
quantity of mercurv at the bottom, and then filled up
with spirit or paraffin ^il. The break thus taking
place under the surface of the fluid is all the more
sudden and complete, and this t\pe of niercurx

break has been, and is.

very popular. The great
disadvantage is the large
quantity of mercury re-
quired (twenty to thirty
pounds in some) and the
rapidity with which the
latter becomes emulsified
and useless for the time
being. Most of the mercurx"
can be recovered, but the
process is very messy.
(See Figure 3.)

Owing to this difficult)'
of cleaning, efforts were
made to find some gaseous
medium to replace the
liquid in common use, and
it was found that ordinary
house gas was all that could
be desired : and it nia\-
be said that an\' niercurx
break designed for the use
of liquid will work equalh
well, or even better, if the
gas is used instead. The
case has, of course, tu he
made tightlv-fitting so as
not to allow free escape
of the gas. Used in this
way the mercury does not
become emulsified, only a
small quantity is required, and the small amount of
black mercury compound that gradualK' forms need
onl}' be removed at long intervals.

The most recent development of the mercur\-
break is a more or less radical departure from the
jet type we have been considering, but the change
is a very important one, and the svstem upon which
they work is one that is likel\- to prewail. The prin-
ciple involved is an old one, though its ajiplication
to interrupters is quite new. It is well known that
if we fill a hollow sphere with liquids of different
densities, and then rotate the s()here rajiidly. the
various liquids will tend to arrange themseKes
around the equator of the sphere with the heLi\'iest
liquid against the wall and the lightest li(]uid
nearest the centre of rotation. Ajjiilying this
principle to an interrupter, the hollow sphere is
flattened at the poles and the equator is bulged out.
This form is found to give the best results, as might
be supposed. (See Figure 5.) Into this jar is placed
some mercury and paraffin oil, and the whole is
mounted upon the end of the shaft of an electric

Gy tJte ctiiirttsy of

Figure 2.

motor, which is placed vertically. As the latter is
set in motion the jar turns with it. and the mercurw
by virtue of its greater weight, at once takes up its
position at_^the widest part. Its rate of rotation is
a little less than that of the jar. which is made of
cast iron, both for its strength and its resistance to
the action of mercur\-. There are several forms of
interrufiter working on this principle, but the above

arrangement forms the
basis of them all. In one
of them, a fibre disc with a
metal segment, and about
the size of a five-shilling
piece, is mounted so that
its edge engages the whirl-
ing band of mercurv. This
causes the disc to rotate
rapidh. and as the metal
segment touches the
mercury the circuit is
completed, to be suddenly
and completely broken
w hen it leaves.

The ■' make "' and
" break " in other modifi-
cations of this type need
not be described in detail ;
they are by far the most
efficient of the mercury
breaks, and the mercury is
not emulsified and used u()
anything like so rapidh".
Electrolytic breaks are not
so much used now as they
were some time ago. These
work on an entireK' different
principle and are the sim-
plest in construction of all
of them. They require a
great deal of current, and
the effect on the X-ray tubes is rather severe, but many
radiologists jirefer them to any other form. Their
action is fully explained in most te.xt books on elec-
tricitx-. but is too technical for an article of this kind.
When we consider the remarkable property of
the X-ra\s in reatlih' passing through substances that
are quite opaque to ordinary light it would seem that
such (lught to be of the greatest use under manv and
diverse conditions. In the early days of their
discovery manv extravagant predictions were made
as to their probable value and these were treated
more or less seriously. As a matter of fact, if we take
awa\- their application in medical and surgical work,
so little remains that the demand for the necessarv
apparatus would be so small as to be unworthy of the
serious attention of an\- manufacturer, e.xcept in the
fulfilment of a special order.

It will be thus easih' understood how difficult it is,
when treating of the uses of the X-rays,' to a\i)id
reference to medical matters. Their limited use in
other directions is due to several causes, and the chief
one is that the X-ra\' image is a silhouette and not a

Messrs. X,-.ot,m if Co.

I'l.itinmii Break.

March, 1911.

KNOWLEDGE.

83

photograph, as it is sometimes erroneously termed.
The propert\- of arresting the passage of the X-rays

ood radiogra})h of the

Figure 3. A Jtt Break.

and thus casting a shadow is jiurelx- a question of the
atomic weight of the elements that luake up an\-
substance. Speaking generalh', substances of
vegetable and animal origin, except the bones, are
ver\- transparent. With the exception of aluminium,
all the metals in common use are more or less
uniformh- opaque. Calcium having an intermediate
atomic weight is seiui-transparent. and as lime salts
enter very largel\- into the structure of most living
organisms, the X-rays are verv valuable in stud\-ing
their normal structure as well as tracing departures
from the normal, whether from disease or accident.
An}- inequalities in thickness are registered on the
screen or plate, and so accurately is this done under
favourable conditions that the details of structure
can often be made out : a
hand or foot shows this ver_v well.

Some verv interesting discoveries ha\e been made
in this way regarding the internal structure of shells,
and the Ravs have been used in examining oysters for
the presence of pearls. If no pearls are present the
oj'ster is returned to the sea, which is presumably an
advantage to the oyster. In a like manner electrical
cables are examined (see Figure 1), both for the
continuit}' of the conductor as well as to see that it
maintains its proper relation to the other members
of the system. The modern electric cable is in
many instances a very highl}- specialised structure,
that has to stand very severe strains both mechani-
cal and electrical, and, as an apparently small fault
may give rise to very serious trouble, the final
inspection has to be carried out with the greatest
care before it is passed as fit for service.

With regard to the medical and surgical uses of
the X-ra}s, most people are inclined to think that

the examination of fractures and the detection of
foreign bodies within the human organism constitute
the main field of their usefulness. These are, of
course. \ery important applications, and ones that
count for nuich in hospital practice particularlw but
they do not by any means constitute the whole. An
ordinary simple fracture occurring in the shaft of a
long bone such as in the middle of the upper arm,
can be dealt with quite satisfactorily, whether
examined liy the X-rays or not : but the surgeon
who attempts to deal with a fracture close to, or
invobing a joint, without having it properly
examined b\- this method, takes a risk to his patient,
as well as to his own reputation, that is not justifiable.
An instance of this is shown in the accompanying
radiograph (see Figure 6) ; this injured wrist was
declared to be a severe sprain and treated as such.
Fortunately the patient decided to come to the
hospital, where it was X-rayed as a matter of
routine. This shows that the bone is not only
broken in at least three fragments, but that one
of the lines of fracture enters the wrist joint. The
fact that there was no displacement of the frag-
ments led to the erroneous diagnosis being made,
and had this been treated in the ordinarv wav a
stiff wrist joint would have resulted almost certainl}-.
In the early da\"s of the X-ra\s their use was
almost entirely confined to stricth' surgical cases ;
now adays the method is used almost as much for the
investigation of medical cases, such as disease of the
respiratory organs, the heart and great blood vessels.

y.V the courtesy of Messrs. XcwUn &> Co.

Figure 4. A Dipper Break.

84

KNOWLEDGE.

March, 1911.

containing' a
that IS ciuite

tumours, and obstructions in the digestive system.
The latter is a comparatively recent development,
and is one that is of great interest. The method
consists of giving jelly or other food
large amount of a bismuth conipouiK
harmless. The bismutli being
opaque to the X-ra\s the pro-
gress of the food can be
watched in its progress along
the digestive canal, and at
times the information gained
is verv valuable. There is a
great danger, howex'er. in mis-
interpreting the aiijiearances.
because similar shadows may
be made h\" \er\' different con-
ditions: in no instance is the
opinion of an expert more
necessary than in this.

Bv means ot \cry [loxwrful
apparatus more or less instan- M — i
taneous radiographs can I'e ly
made of the heart when tht-
X-ra\' tube is placed no less
than two metres Ironi the plate,
as stiowu ill the ilhistration
accomi>an\ iiig the Inst part oi
this article. Owing to the
great distance of the tube, the
si/re of the shadow of the heart
is \er\- nearl\- the same as that
of the heart itself, and it is
the best method at our disposal
for accurately determining the
dimensions of that organ.
Changes in these dimensions
can be detected by making ex-
aminations at intervals. This
hv no means exhausts the list
of applications of the X-rays in
the diagnosis of disorders of
mankind, but enough has been said to show how much
progress has been made, ami the science is 1)\' no
means at a standstill. Improvements in methods and
in personal skill are being introduced every day, and
scarceh- a month [Kisses that does not give us some-
thing new in the way of impro\ed appliances.

It was comparatively soon after the discovery of
the X-rays that some investigators began to employ
the radiation for purposes of treatment. They were
led to do this from the good results tliat were being-
obtained with the ultra-\iolet rays, and from the
fact that mam .\-ra\' workers had begun to suffer
from a form of dermatitis, which was rightly
attributed to the influence of the X-rays themselves.
It was at this stage that the foundations were laiil
for the immense amount of suffering that has been
endured b\- main" of the ])ioneers of X-ray work.
mam of whom still continue to suffer in one \\a\ or
other, ill spite of the fact that the\' haxc taken e\ery
possible precaution since the first attack ot the

scientific as that of giving
ordinar\- drugs. We have no

FiGi'Ri-:

incurred bv those who are working with them more
or less continuously: there is not the slightest
danger to an\- one w ho undergoes an examination or
a course of treatment b\' the .X-rays, so long as the
one who is a recognised expert in
such matters.

It ma^• be taken as an axiom
that am" agent that is capable
of doing so much harm as this
can also be made to do a great
deal of goo(l. if onlv its powers
ari_' propirK controlled and
directed into the right channels.
The ijreat trouble m adminis-

tering these ra\s therapeutically
was that of know ing how large
or bow small a dose was being
gi\'en, and even at the present
time the methods at our disposal
are not anvthing like so simple
an('

s.
]{ satisfactory method of ascer-
taining the exact strength of
radiation the patient is getting
at am' gi\'cn moiiK'nt : our
methods will oiiK' tell us how
r much has been gi\'en. and that
rather crudeh'. The means
mostiv eniplo\'ed are sufficienth'
accurate in the hands (jf one
who has had a considerable
exi)erience of the work, and
who has become more or less
familiar with the vagaries of
the X-ra\' tube. The day is
not \'et that the novice can
dip into this work without
running considerable risk.

When the jdatino-cjanide
of barium is exposed for a
certain time to the influence of the X-ra^•s it turns
tnim its usual greenish-\'ell<iw tint to that of a
light orange. This material is spread upon stiff
paper and cut into small circular pastilles. The
X-ra\' tube is enclosed in a ray-proof shield, from

y /;. Saui/as Electrical Cc>.

Sanax Break in Section.

which the ravs can escape only bv an opening made
tor the purpose, the size and shape of which can be
altered to suit an\' ordinarx' conditions. The pastille
is held in a clip exacth' half the distance between
the source of the ra\'s and the area to be treated,
and is so arranged that it can be removed for
examination from time to time. With each set of
pastilles is supplied a standard tint, to which the
pastille luust change before the ordinary full dose is
given. This is, in outline, the method in use at the
present time by the majority of radiologists. It is.

othe

r

dermatitis. The dan;.

fr

thes

se ra\'s is onl\'

adniittedly, a crude one when judged by
standards of measurement, but in the hands of the
expert it gi\'es very good results. The arrange-
ment is shown on page 498 of the previous article
(" Kxo\Vl,l-:i>('.K,"\'olume XXXIII. December.lOlO),

March, 1911.

KNOWLEDGE.

85

With regard td the conditions that are benefited more capable of withstanding the various and severe
b\- this form of treatment, it may be said that the stresses to which it is subjected, and is also pro\-ided
more superficial is the disorder the more likely is it to with a means of regulating its vacuum ; but it remains
be favourabh' influenced :
this is only another wa\'
of saying that the method
finds its greatest field of

usefulness in the treat-
ment of the diseases of
the skin, and the results
that have been obtained
are at times quite remark-
able. It is a very fortunate
thing that it is among
those conditions that are,
as a rule, very resistent
to all ordinar\- methods
of treatment, that some
of the greatest successes
have been made.

Of course. X-ray treat-
ment is not confined to
cutaneous disorders: their
field of usefulness is a
very wide one, but this
is scarceh- the place to

enlarg

upo

n this side of

m pnncipic as it always
was, and great as its
imi)r()vement has been it
lias not kept pace with
the development of the
electrical side cf the
X-rav equipment. Any
modern coil can com-
pleteh" wreck any X-rav
tube in a few seconds if
desired. Our greatest
want now is a tube that
is steady in action and
in \acuum, that will give
(lUt a certain (jualitN' of
radiation as requireil, and
no other, and contmr.e to
give this no matter how-
great power is applied to
It within the limit of
reasonable requirements.
With a view of meeting
some ot the conditions
it lias been suggested to
make the bulbs of quartz
instead of glass, but so
far no one seems to ha\e
attacked the problem
seriously. Ouartz is
much more transparent
to the X-ra\s than an\'

the questi<in. It is, in

fact, a pity that so much

has been said upon the

medical asyiect of the

question but. for reasons

that are obvious, its

avoidance is a matter of

some difficultw

Before closin" this ,- ^ , ^ , i , , , i ■ i ■ pendent of an\' changes

i:>eioie lio^hi,,., iiiib [.-[Q^f.^ 5_ A li.u uuc ui the lower end ot the radius involving ' - "^.,

article it ma\- be of the wrist joint. of temperature, and will

interest to indulge in Thi> injury cmild not have lieen .-.aurately diagnosed e.vcepl with the assistance of Staild ally amOUtlt Ot rOUgh

a little speculation as the x-r.ays. yg^„g ^vitliin reasonable

regards future develo[)ments. While we have limits. It certainly should be well worth giving a
seen that improvements in the electrical appliances thorough trial, if only for the advantages already
have been soing on from the \erv beginning, mentioned. But even with these advantages it could

form of glass, it is inde-

and show little sign of an\- falling oft' in this
gradual but stead\' improvement, the X-ray tube
itself has undergone no radical change since
the invention of the focus tube bv Professor
Herbert Jackson.

It is quite true that the X-ra\- tube of the [irescnt
day is a great improvement on the original Jackson
tube: it is larerer in size, more stead\- in action. ;ind

not be said that the X-ray tube was in the nature of
a perfectlv satisfactory instrument. In the present
state of our knowledge it is very difficult to see how
the X-ray tube can be radically improved upon.
We can onlv wait patienth- : and for all we know-
some means of getting our X-ra>-s ma)- be discovered
that is much more simple and reliable, and
entirelv different from the methods we use at present.

THE ROYAL INSTlTUTlOiX

A Genek.\L Monthly Meeting of the Members of the
Royal Institution was held on the afternoon of
February 6th, The Duke of Northumberland, Presi-
dent, in the chair. Mr. and Mrs. Alfred Carpmael,
Dr. W^ S. Colman, Mr. Guv Ellis, Mrs. E. B.
Fielden, Dr. A. H. Levy, Mr. Basil Mott, Mr.
A. F. C. Pollard, and Dr. N. Raw were elected
Members. The Treasurer reported that he had

received /],200. part of the legacy to the Ro\al
Institution of the late Miss Wolfe, and ;^'62 10s., a
portion of the legacy of the late Mr. C. E. Laxton.
The special thanks of the members were returned
to Dr. J. Y. Buchanan for his donation of £'100 to
the fund for the Promotion of E.xperimental
Research at Low Temperatures. The Institution has
recently received a gift of £1,000 from Dr. Muller.

HOW YOUNG BIRDS LEARN TO SING.

By G. W. BULMAX, M.A., B.Sc.

Thk (juestion of how a young bird Icarus the
peculiar song of its own species is an interesting
one, although the subject does not seem to lune
much engaged the attention of Naturalists. Walking
from Hexham to Corbridge in Northumberland
early last August, I had the pleasure of listening
to the singing lesson of a voung \-ellow hammer.
One bird, the pupil, with slightly weaker and less
decided song, was answering another which sang in a
clearer and more finished style. There was no
mistaking the fact that the first song came from the
more accomplished songster, and it was hard to resist
the conviction that the other was an imitation. It
seemed, in fact, a \'oimg bird learning to sing.
Several times the instructor gave the complete
song — " A very, very little bit of bread and NO
cheese '" — and the pupil re[)lied also witli e\er\- note.
There was no hurry, and alwa\s a (juite [lerceptible
pause between the songs. Then some three times
in succession the teacher gave the song without the
final note. And the puj^il duh- replied with a song
one note short. Then the instructor went liack to
the complete version, Init so long as I listened it
was answered by the in( miiplete song.

This incident recalls some observations on the
subject made some _\'ears ago. August is a specialh-
fa\'oural)le time for listening to the vellow hammer's
song. Then it seems to come out with a clearness
and beauty peculiar to the season. Whether this is
due to the silence of the louder songsters, or whether
the yellow hammer's song really impro\es by practice
as the year advances, is perhaps uncertain. And in
listening to this August songster I had often thought
there must lie two similar but distinct bird sones,
and tried to make out to which of the buntings
the other could belong. The one song was rapid,
clear, and distinct, the other slow and frequenth'
omitting the proper ending. But listening care-
full}- one afternoon I convinced nnself that the
former was that of the old bird, and the latter
that of the young one learning to sing. First
of all came the quick, clear, decided song, and then,
after a few seconds, the slow, hesitating, and often
stopping short imitation. These were given in
regular alternation for a long time. As I listened to
them, it was impossible to resist the conviction
that it was a young bird receiving its singing lesson.
A somewhat similar account of a voung bird learning
to sing was recorded some years ago in the pages of
a natural history periodical known as the Field Club.
now no longer extant. Personally I have not met
with any evidence that an\- other species learn their
songs in this way. Nor have I come across the
records of anv other observers who ha\e heard

similar singing lessons, except the above-mentioned
case, which, I believe, also referred to the yellow-
hammer. Young robins, song thrushes, and black-
birds, which I have heard making their early efforts,
ha\-e alw-a^■s been singing al<ine.

Many )-ears ago the Hon. Daines Barrington made
some interesting experiments. He reared young
linnets under sk\-larks, woodlarks and titlarks, and
found that in each case thev learned the song of
their foster-parent instead of their own. He
concluded, therefore, that the song of a bird is no
more innate than language is in man. And more
recently the experiment of rearing Baltimore orioles
altogether apart from their parents has been tried.
Two which were thus reared in a fourth iloor flat in
Boston, developed a song of their own. different from
the proper song of the species. Other nestlings
afterwards reared in the company of these two also
learned the new song. Mr. Hudson, again, notes the
case of the oven bird, the >oung of which apparently
learn h\- imitating their parents while still in the
nest. The old birds, it appears, sing a sort of duet
together, and according to the above naturalist, " the
young birds, when only partially fledged, are
constantly heard in the nest or o\-en. apparently
jiractising these duets in the intervals when the
parents are absent."

The direct inutation exiilanation of bird-song is
strengthened by the fact that in many birds the
imitative faculty seems to be strong. Putting aside
the familiar cases of our own starling and the
American mocking bird, the following examples of
imitation in birds not usually n-iimics may be
cited. On one occasion I heard a blackbird cro\\-
like a cock. And I find that Yarrell records the
fact that it is occasionally known to do so. On
another occasion I heard a robin in-iitate the song
thrush. Again, on one occasion only, I heard
a skylark twist the song of a chaflinch into its
own more copious melody. I incline, however,
to think that this may have been unconscious
imitation.

There are birds, how-ever, like the cuckoo, which
apparentlv cannot learn by imitation, whose
song must be supposed to be innate. And the
case of Rliyncliofiis nifcsceiis cited by Mr. Hudson
is of similar iiuport. A 3-oung'bird of this species
was taken from the nest when just breaking the
shell. It was reared where it had no chance of
hearing the song of its species. Yet long before it
was full grown it would retire to a dark corner of
tile room, and give its characteristic evening song
in great perfection.

86

A XEW SPECTROSCOPE AND SPECTR

\PH.

By R. A. HOUSTOUX. M.A.. Ph.D.. D.Sc.
(Xatural Philosophy Dcfxirtnuiit. University of Glasgoic.)

Figure 1.

The tvpe of spectroscope for general use in ph\sical
or chemical laboratories is now prettv well fixed.
There is a telescope and collimator, both with
achromatic glass lenses, the collimator being fi.xed,
and the telescope moving round a divided circle.
If the spectrum is to be photogra[)hed, the evepiece

end of the telescope is
replaced by a box carry-
ing a photographic plate
at its end. With an in-
strument of this kind
work can be done in the
visible spectrum and in
the ultra-violet to about
JjOuu : if we wish to go
further, quartz lenses and
a quartz prism must be
used. Quartz lenses and
a quartz prism will also
carry us considerably further into the infra-red than
glass. But the quartz prism in general use. the
Cornu double prism, gives a sharp image onh' w hen
set at minimum deviation,
and the focal length of a
quartz lens varies so rapidlv
with the wave-length that
the photographic plate must
be set with its surface at an
angle of about 21° to the
axis of the camera. The
focussing of the plate may
thus be a lengthv process.
On account of these compli-
cations and the cost of the
special apparatus involved
moderate means and limited experience
avoids the ultra-violet and infra-red.

The object of this short paper is to describe a
cheap and simple form of spectroscope of radically
different design, which is eminenth" suited for the
amateur who wishes to work in these regions, and
which is also suitable for the visible spectrum. It
does not appear to be known in this countrv, although
frequently used in research work in America. In
this instrument the lenses are replaced bv mirrors,
and the Wadsworth mirror-prism combination is
used. The Wadsworth mirror-prism combination
consists of a prism and mirror mounted together on
the prism table, with the plane of the mirror and
the plane that bisects the refracting angle of the
prism both meeting in the axis of rotation of the
prism table. The diagram (see Figure 1 1 illustrates
a special case of the arrangement : ED and CA are

the experimenter of
usualh"

respectively the traces of the two planes referred to,
and they both meet in A. the point through which
the axis of rotation of the table passes.

Now consider any ray FGHJK (see Figure 2)
passing through the prism at minimum deviation,
and being reflected by the mirror. Its path through
the prism. GH, is parallel to the base of the prism,
DB. and JK is parallel to FG. From A draw AP,
AN and AM perpendicular respectively to FG. HJ
and JM. Then by symmetr\- AP = .\X. and by
equal triangles AM = AX. Consequentlx' .\P = AM.
Suppose that the ray FP is white light : the colour
in this rav that sufters minimum deviation emerges
along JK after passing through the system. Rotate
the prism and mirror through the same small angle,
keeping the direction FP fixed. Then AP and AM
are fixed, and consequently JK is fixed. A different
colour now suffers minimum deviation, but emerges
along the same straight line JK.

Suppose now that the single ray FP is replaced
b\- a beam of parallel rays and that the prism table
is rotated : each colour in turn, as it suffers minimum

deviation, is unde\'iated and
at the same time suffers
the same constant parallel
displacement.

The next diagram (see
Figure 3) shows how these
properties are taken advan-
tage of. .A BCD is a solidly-
made box, the lid of which
has been removed and into
which we are looking
verticalh' down. S is a
slit attached to a piece of brass tubing which slides
in a short piece of tube fixed in the side of the
box. The light from the slit is rendered parallel by

Figure 3.

87

88

KNOWLEDGE.

March, 1911.

the concave mirror M^. It is then acted on by the
mirror-prism combination, falls on the other
concave mirrOr Mo. and is brought to a focus on
the photographic plate at P. The concave mirrors
are placed at their calculated distances and an\-
necessar\- adjustment is then done bv sliding in or
out the slit until the image of the latter, when
illuminated with Na. light, is perfectly sliarp nn the
ground glass plate. Then, since the focal length of
a mirror is independent of the colour of the light, all
the spectrum is in focus away into the ultra-violet.
Suppose that a quartz prism is being used and
that the photographic plate is replaced by a fixed
evepiece with crosswires. Then, if the mirror M., is
adjusted so that the Na. lines coincide with the
crosswires when the\' arc at niinimuni dex'iation. and
the prism table be rotatecl. e\L-rv line comes into
minimum deviation as it reaches the crosswires.
That is, we obtain maximum definition automaticallv.
The same holds if we are examining the infra-red
with a linear thermopile. The thermopile remains
fixed and we move the spectrum across it and ever\'
line as it reaches it mo\es into perfect focus, a
pleasant contrast to the quartz spectroscope where,
for ever\- wave-length, we have to adjust both for
minimum deviation and the correct distance of the
theruKipile from the lens.

Other advantages of this mirror spectroscope are
its compact form and the absence of diffuse light.
When light falls on a lens, eight per cent, is reflected
back : here the light not used is absorbed by the
mirror. Also, there are no tubes to reflect light at
grazing incidence. The instrument may also he
used as a monochromatic illuminator.

For the mirrors I have used plate glass and cheap
concave lenses silvered. As it is the outside surface
of the silver that is used, it is better to send the
glass to an optical firm to be silvered. In calculat-
ing the position of Mj and M., allo\\ance must be
made for the obli<]uit\- of the incidence. The
correct distance between S and Mj or P and M., is

, , r cos '/' , . , , , ,,

not r/i but 7^ where </> is tiie angle between tlie

incident beam of light and tile normal to the
mn ror.

The disadvantage oi silver mirrors is that the)'
reflect light at 310 /u/n. ver\" poorly. Consequently,
that part of the si)ectrum is usually wanting,
although the region beyond comes out well enough.
Spiegel magnaliuni mirrors, howexer. reflect well to
the very end of the si)ectrum ; I ha\e no experience
of them. but. according to the tables, if they are used,
the spectrum should be ex'erywhere as bright as w ith
ipiartz lenses.

A NATIVE iX .MULRXI.XG I-UR A DUG.

By the courtesy of Mr. Fretlerick lionneN' we are
enabled to imblish the accompan\ing photograph
of an old native woman of Australia
who is shown in "half-mourning"
(num-muyn-ka). Mourning con-
sists of cox'ering the head with
plaster, and in half - mourning a
broad band of the latter is put
over the head from front to back.
The remains of this are seen in
the picture, the special interest
of which is that the signs of
sorrow were put on, not owing
to the loss of a human relative,
but on account of the death of a
favourite dog.

After the period of mourning is
over, the plaster must not be
removed, but allowed to crumble
away. Incidentalh' it ma\- be said
that the bag which the wDinan is
netting is one that is usualh'
carried suspended between the
shoulders, the ends being tied
under the chin. In such a bag,
the women carry about small
possessions or an infant if they
are moving about with one.

The photograph was taken in Ajiril. 1S,S
Momba. l\i\'er Darliii!/. New South Wales.

1. at

An Abiiri.^inal Wnin.in of Australia nettint,' a bag.

The plaster on her licid is the remains of half-mourning after the death of her dog.

SCIENCE IN EVERY-DAY LIFE.

Bv Rkv. H. X. HUTCHINSON. B..\.. F.G.S.. F.Z.S.

■■ KN()\vi,kd(;e grows, but wisdom lingers. "" These
weight\- words of the late Lord Tennyson are,
perhaps, just as true now as when the}' were penned,
over htty vears ago. Scientific knowledge has indeed
advanced by leaps and bounds in that short space
of time. The chemist, the astronomer, the student
of phvsics, geologN', or of biology, all stand now on
a different foundation, and bv the help of modern
instruments and the wonderful results obtained
bv methods of precision, they are privileged to
see a little further into the mysteries of the
trulv marvellous Kosmos in which we live, and
to read, however imperfecth". some of the riddles
of Nature. But when we ask whether the civilised
races of mankind ha\e made an equal progress
in wisdom, we ari- obliged sorrowfulh- to confess
that the answer must be in the negative. Were
we trulv wise we should endeavour seriously to
appK- some of all this scientific knowledge to the
practical problems of every-da}' life. We ignore the
teaching of Science as far as it touches our habits
and wa\s of life. We do not think scientifically.
A few individuals here and there may do so, but, as
a nation, we certainly do not, and the consequences
of this neglect are of a serious nature. In spite of
the warnings of kindh' Nature and the advice often
offered, freelv and with goodwill, bv those who know
and realize the importance of obej'ing her laws, and
following her wise councils, we continue in our ow n
foolish way; perversely making paths of our own
that are dangerous, na\-, even forbidden ; doing some
things in ways that are quite wrong, and others
that ought not to be done at all. As the prophets
of Israel solemnh- warned the people of their
day of moral evils, and of unrighteous wavs, so men
of science, in the twentieth century, ma\- well take
upon themselves some portion, at least, of the seer"s
duty, and speak in no uncertain tones of the misery
and waste and suffering that follow from disobedience
of Natural Law. Such warnings might well be graven
deep on tablets of stone, and brought down from the
sacred mountain of knowledge to the plains lielow.
to be set up in the eves of the people. We surelv
cannot dispense w ith the aid of Science : at ever\-
step we need her help — at our peril do we neglect
her wise counsel. She is Athene to the modern
Ulysses. When we enter the world, Science, in the
person of a medical practitioner, stands by to help
our arrival, and when we seem likelv to leave it he
is also there, in case he may possibly be able to keep
death away, or at least to help us in our last
moments. One ma}- go a step further and sa}-, that
if the laws of heredity were considered in the making
of matrimonial alliances, the health of the races
could be vastl}- improved, and much quite unneces-
sary suffering avoided. The time will come when
the science of Eugenics will take its proper place.
In the following pages, the writer begs humbl\- to

offer a few thoughts and suggestioHG;, to those who
will accept them, in the hope that chsy may be of
some service in a good cause. They are offered
more especiall}- to women — and doubtless the
readers of "Knowledge" are not all men — because
they refer largeh' to domestic matters, and, in the
house, woman is rightl}- supreme. She it is who is
responsible for order, cleanliness, comfort and the
suppl}- of food, light, air, and other things so truly
\ital to a proper health}- existence. There is hardly
an}- Hmit to her power in this domain; in her hands
lie the man"s peace and perhaps his verv life.

The first thing to consider is the house we live in,
and its environment. Nobod\- would w-illingly
choose an unhealthy place to live in, but supposing
that circumstances compel us to dwell in such a
district, we can at least see to it that our homes are
not insanitar}-. It is a good plan, in these cases, to
call in the aid of a professional expert, a sanitary
engineer or an architect. All who study these
n-iatters are aware of the fact that houses have been
built in situations where good health is hardly
possible. excei)t perhaps to a few- exceptionally strong
men and w(in-ien, places where damp prevails,
bringing with it lung troubles, rheumatism and a
lowered vitalit}-. In these places the death-rate is a
high one. For example, the situations of our two
chief Universities are bad — they would never have
been chosen b}- their pious founders had they known
something of the Science of Sanitation. It is to
be hoped that, in the good da}-s to come, the building
of dwelling houses on such sites will be stricth-
forbidden, and on those which may be moderately
unhealth}-, onl}- such houses should be allowed as are
built on arches, as recommended b\- the late
Dr. B. W. Richardson. This simple plan would
keep out damp to a large extent. It is sad to think
how many ^-aluable lives are lost, or at least partl\-
ruined. b}- neglect of these simple precautions, w liich
even a slight knowledge of science would suggest.
The writer has frequently seen country houses
surrounded b}- so many trees at a short distance as
to render them decidedly dark and unhealthy. Now
darkness in a house is a thing to be carefull}-
avoided. It is bad for the mind, because darkness is
depressing, and all depressing influences should be
avoided. It is bad hygienically, because evil germs
flourish in darkness, w-hile sunlight kills them.

Labour-saving appliances should be welcome in
these days, when good servants are not easy to
obtain (and are inclined to leave us after a year or
two). But there is one plan which the present
writer has often strongly advocated which, perhaps,
more than any other, would save labour, and that is
the provision of hot and cold water in every bedroom,
together with a waste pipe of proper width to take
away water which has been used, and other things.
This idea is not new. for it is being carried out in

69

90

KNOWLEDGE.

March, 1911.

some of the best and most up-to-date hotels, where
labour-saving is most important.

Doubtless guilders might object to the extra
expense, but as soon as the public demand such a
change it will be made. The only dela\' « ill be in
educating people to make the demand. Linoleum
might be used to a greater extent: most houses have
too many carpets, curtains and other hangings which
collect dust. On entering the house dirtv boots
bringing in mud might be changed for slippers.

The writer does not propose in these articles to
discuss the action lor maction) of corporate bodies,
a subject on which much might be said, but
it may suffice to point out the importance of
scientific knowledge to our local rulers. The more
they know of science, the fewer mistakes will they
make. Li spite of frequent warnings in the dailv
press, few people realize the dangers lurking in w ater
and milk, two of the prime necessaries oi life. The
public are in the habit of drinking water an\-where
and everywhere, without making anv enquiries as to
its purity and origin. A very good rule would be to
refuse to drink the water provided in hotels,
restaurants, or lodgings unless guaranteed to be
effectively filtered. There are good filters to be
obtained which will effectually stop all bacteria, if
kept clean and in good working order, such as the
"Pasteur" (which has been subjected by expert
bacteriologists to severe tests). Perhaps a safer plan
would be to boil all the drinking water, and charge it
with carbonic acid in large gasogenes made for the
purpose. This would make it pleasant and sparkling.
When travelling abroad, it is still more important to
avoid the drinking water, and to drink onh- w ine or
beer, or mineral waters of guaranteed qualitv. With
regard to milk, it may be safely said that the danger
is still greater : and one is glad to observe that more
attention is now paid to this subject, both b\- the
general public and by sanitary authorities, for
it is a most serious question. Tuberculosis in
children is frequently due to milk from a tuber-
culous co\\-. Diphtheria, scarlet fever, typhoid, mav
often be traced to a similar source. Consequenth-
it is most important that both dairymen and
farmers should take every reasonable precaution
to keep the milk clean and pure, for it is a
most favourable soil for harmful bacteria. Also
milk, when it reaches the house, should be kept in a
cool place, away from the sun, and it is a good plan
to cover the basin containing it with muslin (fixed
on a wooden hoop), to keep out flies and dust.
Dairymen mostly adopt this practice now, and
housekeepers should follow their example. Most
farmers are not sufficiently careful about the con-
dition of the cow-house and its surroundings. Any
sort of refuse carelessly left near these places ma_\'
be a real source of danger, on account of the flies
that breed on refuse heaps. Milkers must keep
their hands clean, and milk-pails must be scalded
with pure water. Sir James Crichton-Browne and
others have spoken plainly to the public on the
danger of flies, and it is greatly to be hoped that

these warnings w ill be heeded. Some of the London
streets might be washed and brushed very much
more than they are. Where there is much traffic,
one often sees horse manure lying about in large
quantities. Flies are attracted to it, and when
dried by the sun and air it is carried about like dust,
enters shops where food is sold, and contaminates
it. This is a matter in which doctors and public
men may do good service to their fellow-citizens, hx
writing to the newspapers and bringing pressure to
bear on local authorities. The power of the press
is enormous, and consequentlv the education of our
verv unscientific public, in these davs, is largelv in
the hands of the journalists ; on them rests a heavy
responsibility. One is glad to see a popular news-
paper, such as the Daily Mail, devoting some of its
space to matters of this kind, for in so doing it
renders the nation a service of untold value.

It cannot be denied that a great deal of food is
wasted, not by any one class of people, but in houses
of all classes. \\'aste of anv kind is unscientific,
and quite wrong economicallv. One of the triumphs
of modern science is the way in which bye-products,
or so-called " waste,"' in manufacturing processes,
have been turned to account and made a source of
increased profit. Even the refuse from our houses
can be converted into " producer gas." and supple-
gas engines for working machines, or for making
electricity. What can be accomplished on a large
scale can also be carried out on a small one, and,
probabh', more effecti\'elv. A great deal of teaching
is wanted to bring home to the minds of women the
full meaning of all this \\ aste.

It is true that much care and supervision is
needed in order to prevent waste, but the lad\' of
the house (or housekeeper, as the case may be) should
regard this as an imperative duty. \Miere coal fires
are used (and these are quite wrong scientifically,
as will be shown later) a good deal of valuable coal
is wasted b\' servants, who are too careless or in-
dolent to separate the white ashes from the unburnt
coal, and so both alike are thrown into the dust-bin,
to mix with organic refuse, such as cabbage leaves,
and so on. To anvbody who regards this question
scientifically, it is quite clear that the organic matter
and the inorganic matter should be strictly kept
apart from the beginning. In the countr\', cottagers
set a good example in this matter b\- putting coal ashes
on to flower-beds, or some other part of the garden,
and keeping the waste food-stufts to feed a pig or
chickens. Now it may be troublesome for town-folk
to make this separation, but it would be well worth
while to do it, and so to increase the national wealth
and welfare. There should be two dustbins, one for
coal ash (i.e., real ash, not lumps of coal), pieces of
china, wood, iron, paper and other such refuse ; the
other for food-stuffs. The lady of the house should
give instructions to her ser\-ants to use a sieve for
separating the coal ashes from unburnt coal, the
former to be throw n away (which seems a pity, for
the\- contain potash, soda, lime and iron silica, and
50 on. all of which can be used by plants ; in country

March, 1911.

KNOWLEDGE.

91

houses these should be put on one side for tlie
garden). The latter should be used for making up
the fire. The other bin may be used for organic
refuse such as cabbage leaves and stalks, lettuce
leaves, potato peelings and pieces of unused vege-
tables (tea leaves are often kept for use in sweeping
floors), bones, after being used for soups, bits of
meat. Bread and toast should never be thrown
awav, as thev often are, even in the streets of the
poor. All these things are to be regarded as valuable
bye-products of the house. Some means ought to
be devised for regularly collecting this matter from
house to house ; attempts in this direction are being
made here and there by the Salvation Army and
certain Sisters of Mercy. \\'e presume that soup is
made of this material, but a far better plan would be
to use it for pig-feeding, in which way it would be
more completely used and converted into bacon
(which, at present, commands a high price).

The keeping of pigs by country labourers, farmers
and others would thus be encouraged. The local
authorities in towns, who at present take away all
the house refuse, would be extremely glad to see
such a change as this, for their carts would onl\- be
required to take away the inorganic matter, and thus
much trouble and expense would be avoided, and
that would mean a saving in rates (which in most
places are rapidl\- rising). On the other hand,
municipal piggeries might be worth considering.

Ladies might well devote more attention to tlie
subject of food and diet. Our health depends
partlv on the food we eat. and the way it is
kept and prepared. It may safely be stated
that the hygiene of the larder and scullery in
most houses is somewhat neglected. Meat guards
might be used much more extensively. Rats and
mice should be ruthlessly exterminated, as well as
cockroaches and flies. Tinned meats should be
avoided, especially tinned lobsters, oysters, shrimp
paste, and so on. Even tinned fruits are not quite
safe. Meats are now often done up in glasses, but
air occasionalh' finds its way into these, causing
decomposition. Ladies who do not study the
hygiene of food would be surprised if they knew of
the dangers that lurk in tinned foods. A good plan
would be to give a general order to the cook that
no such preparations be allowed to enter the
house. Raw oysters are by no means safe — they
should be cooked, and so should escallops and mussels;
the latter are very wholesome and nourishing.
Wholemeal bread is far preferable to the ordinary
white kind, which unfortunatelv lacks some of the
most important constituents of the wheat grains.

Steam cookers both for meat and vegetables should
be used ; in this way valuable salts and juices are
retained, which bv ordinary methods are lost.

The adulteration of food is a subject on which
much instruction is wanted. More public analysts
and public inspectors are greatly needed. Magistrates
should inflict severe sentences in those cases where
the evil-doers are brought to justice. In all our large

towns a great deal of diseased meat is sold to the
poor, especially in the form of sausages. Vegetarians
avoid these dangers, and they set a good example; but
those who do not wish to abandon a diet of flesh
might well take less of it, and pay more attention to
fruits, vegetables, milk and cheese, which are quite
sufficient to keep us in health. We should then
hear less about ptomaine poisoning, which is
frequenth' connected with the eatiuL' ■ ' k^pies.
Fruits might be used by all classes a gr^ .,. i more.
Every countrv in the world can send its fruits to
Great Britain and Ireland free of anj' tax. This is
a great national blessing, and one which is hardly
appreciated as it ought to be. Young people might
be encouraged by their parents to eat apples, oranges,
grapes, nuts, figs, raisins, dates, plums, currants, and
so on, and at the same time to consume less of pastry,
sweets, pickles and sauces. Parents ma}- reph' that
many fruits are expensive. To this we may say,
apples and oranges can be obtained cheaply by
buving in large quantities, especialh' from the stores.
The very finest apples, for example, can be purchased
at about \\A. each by buying a large box containing
about one hundred and twenty. The same with
oranges. The fruit ma\" easilv be stored on wooden
shelves in a wine cellar, and the riper ones picked
out for present consumption, leaving the rest to
ripen graduallv for a month or two. They do far
more good to the \'0ung people than luedicines.
Their use tends to keep down doctor's bills.
Unfortunately, the less educated portion of the
public still puts great faith in patent medicines and
patent foods, and their credulity is incomprehensible ;
Iving advertisements, and the promises held out
therein, are accepted with a faith that is simjily
amazing. Nothing but education can stop this
growing evil, for no Government has the courage to
warn foolish people in such matters ! Much might
be said about the excessi\'e use of stimulants,
narcotics and drugs, but it is impossible to deal
adequateh' with the subject here. Suffice it to sa}-,
that for most people the less alcohol they consume
the better. Man)- old people have attributed their
long lives to total abstinence. Even the doctors are
much less in favour of alcohol than in former times.
But with regard to tea and coffee much might be
said ; onl\- we fear the ladies will not thank us for
saving that the excessi\'e use of tea (and coffee) by
all classes is really a grave danger! It is taken far
too strong and too frequently, and it should be
poured off into another vessel after standing three
or four minutes. Medical men are beginning
to realize the magnitude of this evil. On all sides we
hear of people suffering from " nerves,"' and yet they
continue drinking large quantities of tea. When to
these habits the}- add want of exercise, excessive
eating (often of over-rich food, highly spiced with
sauces), and somewhat idle habits, what wonder
is it that they become depressed, morbid and
unhappy ? When the mind is left uncultivated by the
verv best literature and art, the effects are still worse.

( To he cuntiiiiicd I,

BIRD LIFE ON THE CAERNARVON COAST.

MARITIME HABITS OF THE LAPWING,

RESEMBLING THOSE OF THE RINGED PLOVER.

By A. R. HOR\\OOI)
(Leicester Museum I.

When staying for a few weeks on the Caernarvonshire
coast at Criccieth, and engaged in the study of the
habits of the different shore-birds and those
frequenting the mouths of estuaries, I came across
the nest of a Lapwing iVaiielltis viil)Jaris) containing
five eggs, which were generally unlike the ordinary
type of plover's egg, in being both shorter and
broader. All the eggs were similar in shape, and the
coloration and markings were normal, but of course
the number (five) was unusual.

Likewise the nest was quite characteristic, though
more carefully constructed than is often the case in
inland stations, consisting of more ample material,
being composed of dried bents. It was placed at the
edge of the coarse grasses. Fesfiica. Agropyroii, and
so on. fringing the sandy beach. This was not more
than a dozen \'ards from high-water mark. Between
the line of \egetation and the sea there \\ere patches
of shingle. Amongst the pelibles forming the
shingle, the Lesser Tern breeds ; and among the
fine and sandv stretches removed some distance
from the beat of the surf tlie Ringed Plo\'er nest?.
whilst lower ciown still, in coarser sand and shell
fragments, quite close to the w ater"s edge, nests of the
Oyster Catcher could be found. Indeed these three
species (all of different genera) form a more or less
constant avian association characteristic of low-lying
littoral flats, especially along the western coasts of
the British Isles.

When discovered, the Lapwing's eggs were warm,
indicating that the bird had but just left the nest.
Here it might be urged that the eggs were warm
owing to the heat of the sun, and that the Lapwing
is in the habit of leaving her eggs for the sun to
hatch, but this would not obtain in this instance, as
the day was dull, if not chill}-, and, moreover, we do
not credit this belief. No bird at least had risen up
from this bit of coast, upon which I had been
reconnoitring for some time, having beached the
boat by which I had approached it. And for a
considerable period I had been experimenting in
the search for nests of the Ringed Plover, Lesser
Tern, and Oyster Catcher, a good lesson in bird
habits.

Now it is well known that the Ringed Plover does
not get up and fly away at once, or circle round and
round an intruder upon the approach of a human
being to the vicinity of its nest. But. on the other
hand, it simvih' leaves the nest unobserved lif

possible), effecting this b\- running in and out of the
piled-up masses of parti-coloured shingle which in
plumage it closeh' resembles. Then, having removed
to some distance, it mav be noticed perched upon
one of the rolled pebbles which strew the beach in
great profusion. This manoeuvre may be followed
easily and closely b\- one conversant with the habits
of these birds, and is most marked, contrasting as it
does in so noticeable a manner with the habits of
the Lesser Tern.

Likewise, inland, the habit of the Lapwing when
its nest is approached bv a person — even some
distance awa\', it ma\' be. from the actual where-
abouts of the nest — is totalK' dift'erent. For on first
obser\'ing the intruder it quietlv runs unseen lor
some little distance, then as quickly and stealthil)
takes wing, and, circling at first round and ri)und
the intruder, it repeatedh' tries to inveigle him
further and further awa\' from its nest b\" sweeping
backwards and forwards at a point and in a direction
as far as possible removed from the nest : and now ,
appearing above the top of some hedge close by, it
undoubtedly endeavours, bv its anxious noise and
vigorous flights to and fro, to trv and deco\- the
eneni}" aw a\'.

Not so, however, when nesting along the sea-coast,
for here it has undoubtedly habits similar to those of
its somewhat near relative, the Ringed Plover ; and,
instead of getting up some distance from the nest, it
runs along, remaining, like the Ringed Plo\'er, at a
distance amongst the shingle until the danger is past.
This, moreover, is easily accomplished amongst the
bushv grasses at the edge of which it nests. Though
several nests were found in the same locality under
similar conditions, no birds were seen.

Somewhat exercised in mind as to how to account
for this evident change of habit of the Lapwing when
nesting on the sea-coast, as compared with its well-
known and curious behaviour w hen breeding inland,
and nesting on pasture or ploughed land, and not
know ing whether or not mv experience was unique,
upon my return to Shropshire, where I was then
living, I mentioned this interesting habit of the
Lapwing to Mr. H. E. Forrest, of Shrewsbury, who
was then, as now, particularly interested in the
fauna of North \\'ales (of which his recent work is
)ierhaps a summary). I was naturally surprised but
delighted to find that he was able to bear out my
experience, wIkii I related the circumstance to

92

March. 1911.

KNOWLEDGE.

93

him, though he had not. until I pointed out the
resemblance in habit between the Lapwing and the
Ringed Plover, noticed that this was the case. Mr.
Forrest wrote me as follows: "I was struck hv \-our
remarks as to the behaviour of Peewits nesting bv
the sea. Though I hardl}- noticed it at the time, I

should say, is of long standing. It is a curious fact
that the Ringed Plover's tactics are identical along
the sea-coast. Is this mere coincidence, or were
the habits of the Lapwing originally like those of
the Ringed Plo\-er, and has it modified its breeding
habits when nesting inland ? Its migratorv habits

Ff-otu n /'//,

P~.ivh:i: /■!• /(•. .1. (,". .!/,.<,,•,

Lapwing. Ringed Pluver. Oyster Tern and Little Tern, nesting together.

now remember that the\' leave the nest ijiiite
unobserved, and do not tly around in the wa\' we
always see them inland."

It seems probable, from the uniform shape of the
five eggs found, that the Lapwing nests habitualh" in
the same situation at the locality named, and that
the habit it has acquired, or exhibits, perhaps we

and generally conspicuous appearance rather suggest
that once it was generally a frequenter of marshy
tracts or areas not given over to cultivation, and
indeed we must remember that it is onl\- of com-
paratively recent \'ears that cultivation has been
general in the way that it is now carried on. At
least the case is interestintr.

ANNOUNCEMENT.S.

THK PHYSICAL SCJCIETV OF LCJNDON.— We are
informed that owing to an alteration in the publications,
papers read before the Physical Society of London in future
will appear in general only in the Proceedings of the
Society and not in the Philosophical Magazine. The
Proceedings and other publications are now obtainable
by the public from the publishers to the Society, The
Electrician Printing and Publishing Company, Ltd.. 1, 2 and
3, Salisbury Court, Fleet Street, London, E.C.

THE BRITISH ASSOCIATION.— For the meeting of the
British Association for the .Advancement of Science, which is
to tal<e place this year at Portsmouth, on August 30th, and

following days, under the presidency of Professor Sir William
Ramsay, K.C.B., F.R.S., the following presidents have been
appointed to the various sections : Mathematical and Physical
Science, Professor H. H. Turner. D.Sc, F.R.S. ; Chemistry,
Professor J. Walker, D.Sc, F.R.S. ; Geology, A. Harker,
M.A., F.R.S. ; .Zoology, Professor D'Arcy W. Thompson, C.B. ;
Geography, Col. C. F. Close, R.E., C.M.G.; Economic Science
and Statistics. Hon. W. Pember Reeves ; Engineering, Professor
J. H. Biles, LL.D. : Anthropology, Dr. W. H. R. Rivers,
F.R.S.; Physiology. Professor J. S. Macdonald ; Botany,
Professor F. E. Weiss, D.Sc, with W. Bateson. F.R.S., as
chairman of the sub-section of Agriculture ; Educational
Science, Right Rev. J. E. C. Welldon, D.D.

NOTES UPON THE EUNDAMENTAE SYSTEM

OF STARS.

Bv F. A. BELLAMY. Hox. M.A.. F.K.A.S.

Of all the branches into which astronomical work
may be divided there is none of greater importance,
none to which more time has been devoted at the
observatories during the past two hundred and fift\'
\ears, and none that has proved so useful in our
dailv life, as meridional or star-catalogue work.
Some hundreds of star-catalogues e.xist, small or
great, and the aim of all has been to re-obser\'e the
brighter stars and obtain improved positions, and to
observe and determine the positions of other and
fainter stars ; the object being to fix or ascertain a
large number of points of reference in the skw much
as geographers do uiion the earth.

The object of these notes is to draw attention to
perhaps the most important piece of work ever
undertaken in this branch, and to place before our
readers a general summar\- of the proceedings which
led to its being started, and of the present condition
or progress already made.

Some remarks will be made upon the scheme
[jroposed, the pecuniar)' and other help received b}'
the Dudley Observatory, the erection of a southern
obser\'ator\-, the inauguration of the work there,
also attention will be called to future proposals and
ultimate aims; and, finalh'. a translation from the
Spanish of an important paper b\" Professor R. H.
Tucker, dealing with the actual details of the work
and its progress at San Liii/, in Argentina, up to last
Julv, will be appended.

The success of the great scheme depends upon
three sources: Professor Boss, who has initiated,
planned, and is natural!}' at the head of the work;
Professor R. H. Tucker, the most eminent meridian
worker, who has charge of the observational part :
and the Trustees of the Carnegie Institution of
Washington, who have provided the mone\'.

The headquarters of the work will be at the
Dudle\' Observator\', whose director is Professor
Boss ; the thousands of stars selected for observation
were first observed there, then the same meridian
instrument was taken to the southern obser\'ator\-
at San Luiz, and when the instrument has been
returned to Albany, the stars at first observed there
will be re-observed. There are various excellent
reasons why this should be done.

The Dudley Observator\-, near Albany, U.S.A.,
%\as founded in 1S51, by subscription, principally
aided by the generous donation of Mrs. B. Dudley —
hence its name. It was organised in 1856, and placed
under the direction of Dr. B. A. Gould. Until
1877 it was chiefly a nieteorological observator\',
but in 1878 a section of the Astronomische Gesell-
schaft scheme for the re-observation of all the
Bonn Durchmusterung stars as bright as the ninth

magnitude, and a considerable selection of others
a few tenths of a magnitude fainter, was under-
taken at the Observatorv ; the work of re-observing
8,241 stars between +5" 10' was commenced on
.\ugust 19th, 1878, and completed on August 5th,
188.Z; each star was observed twice or more times.
Professor Boss was engaged on the Zone observa-
tions and reductions throughout ; the assistants.
O. H. Landreth, T. I). Palmer, and R. H. Tucker
were helping for one, three and four years
respectively. Of Mr. Tucker, who was in charge of
the whole work during Professor Boss's absence in
Chili to observe the Transit of \'enus. in December,
1882, the Director has acknowledged that " the
recortl of observation and cominitation bears,
throughout, high testimony to the character of
his efficienc\' and zeal." This catalogue of 8,241
stars was published in 1890 and was one of the
first two published in connection with that great
and important scheme. It was accomplished by
means of the Olcott Meridian Circle — so named
from a generous donor of funds — constructed by
Pistor & Martins of Berlin, in 1856, and is of
eight inches aperture and ten feet focal length.

The position of the Observator\' there was
4'' 54'" 59^-2 W. of Greenwich and 42" 39' 49"- 5
north latitude; it was one hundred and se\'ent}' feet
abo\e the sea and situated on the northern side of
the city of Alban_\' in the valley of the Hudson river.
Ow ing to the smoke and disturbance from engines
and trains from the railway and from the frequence
of local mist and fog, good work was interfered with,
so much so that it seemed advisable, if not imperative,
that the observatory be refounded on a new site;
the mone\' was forthcoming — as is usual for
astronomy in the U.S.A. — and about 1893 the
observatory was rebuilt on its present site, not
very far from its original locality. Besides the
Olcott Circle its other chief instrunient is an
equatorial telescope of twelve-and-a-quarter inches
aperture by Brashear, \\'arner & Swassey. The
exigencies of the meridian work have prevented the
equatorial being much used. It is this Olcott Circle
that has been temporarily moved to San Luiz.

Since the Observatory has been under the direction
of Professor Lewis Boss, the chief work has been
meridian observations, researches ujion proper
motions, and motion of the solar s\'stem. The most
recent work has been the observation and preparation
of a catalogue of positions and proper motions of all
stars to the seventh magnitude, in connection with
the department of Meridian Astrometry of the
Carnegie Institution of \\'ashington, which Institu-
tion has ajiproprialed to the Dudley Observatory,

94

March. 1911.

KNOWLEDGE.

95

under grant No. 100, /LOGO for: — (1) The com-
pletion and publication of a catalogue of about
10.000 stars. 8.000 being between declination —20° to
— 37°, to the 7'5 magnitude : these observations were
made between 1896 and 1901: (2) For the homo-
geneous determination of star positions and motions,
computed and discussed from all available observa-
tions and star catalogues, to the sixth and in some
cases to the 7'5 magnitude, with an accuracv of the
highest possible order. This Preliminarv General
Catalogue, formed from \arious sources, has no\\"
been published: it contains the positions of 6,188
stars reduced to the epoch 1900'0 and includes
results which are primarily designed to furnish
a large number of systematically and accurately
observed motions of stars. The intention was to
include all stars that seemed to show a proper
motion of 10" a century, derived from observations
made at various observatories. In Januar\-. 1902.
Professor Boss again made application to the
Trustees of the Carnegie Institution for aid in a
general investigation of both the nature and amount
of the motions of the stars. Specific things
proposed to be investigated were Ui) the direc-
tion and velocitv of the solar motion in space
to be determined with far more accuracv than at
present known ; (b) to investigate the subject of
" star-swarms," — swarms of stars moving in a
common direction like meteors — a new subject, to
which Professor Boss has been specially attracted :
(c) to determine with accuracv the relative distance
of various orders of stars ; id) to determine the
constant of precession more accuratelv than is now
known ; and to examine other questions as the\- arise.
Professor Boss considered that, as the basis of these
investigations, the motions of the stars must first be
accurately known, and that this would be both the
greater and the most laborious part of the work.
It is with this general investigation and the specific
in\-estigation {a), that Professor Boss and his staff
have been progressing to the extent to be indicated
later.

The fact of so much having been alread\" accom-
plished served to prove bevond doubt to Professor
Boss that the real value of his results to that period,
about 1904, and of the final discussion, will depend
upon the systematic accurac\- of these determinations
of motion, and upon having a good determination of
motion for each star. Both these requirements
called for further special observations, the great need
in this direction being a new determination of the
positions of the standard stars, distributed from the
north to the south pole of the skv. Professor Boss'
plan proposed to the Carnegie Institution was further
supported by those results. The Dudley Observatory
Meridian Circle was then being altered to meet his
views with regard to such standard work. Aided by
a grant, the first series of re-observation of the
selected standard stars or points of ultimate refer-
ence, would be completed at Albany within about
two years ; after that he proposed to dismount the
instrument and re-erect it upon a suitable site in the

Southern Hemisphere. The places he had selected as
eminently suitable were San Luiz, in .\rgentina,
specialh- recommended by Mr. JJavis, the chief of
the meteorological service, as possessing an excellent
and stead}' climate ; another was Bloemfontein, in
South Africa, highly recommended by Sir D, Gill,
and places in Australia were also suggested. The
idea in selecting a southern station was to observe
stars at .\lbany from the north pole to as far south
as possible, and then to use the southern observatory
for observing stars from the Albany zenith to the
south pole, and so interweave the two series that
the elimination of systematic errors of observation
might be effected by making them work in opposite
directions in the two positions of the instrument.
As a necessar\- addition to this proposal it was further
urged that special re-observations be made of those
stars, mostly south stars, which had been neglected
during the past twenty to thirty years ; the accuracv
of the places of these particular stars is much desired
in order to obtain improved knowledge of their
proper motions, and so help to bring up the quality
of their places to approximate that of the standard
stars. Professor Boss said that in one-fourth of the
southern skv, that near the southern pole, only thirt\-
per centum of the stars to the seventh magnitude
had been accurateh- observed since 1880, and scarcely
anv since 1894 : the need of their re-observation was,
therefore, ver\' great and urgent.

In connection with the Carnegie Institution's
desire for the establishment of a southern observa-
torv it was proposed b\- Professor Boss, and warmh-
supported bv eminent astronomers, that his particular
scheme of research work, essentially referred to in
(ci) — the re-observation and determination of standard
positions of a large number of stars from the north
to the south poles of the skv — was specially that kind
of work for which a portion of the funds of that
Institution could be most appropriately utilized,
especialK' as the qualifications, time, and energies
of several astronomers were now awailable for
carrying out such a grand scheme. In making this
application to the Institution, Professor Boss said he
\\ould use the same instrument as employed at
Albany, which he considered to be one of the finest
meridian instruments in the world for such work,
and one in which the investigation of the division-
errors of its circles has been accomplished with
the highest degree of accuracy, by the combined
labours of four observers lasting more than a year.
He proposed to take personal charge of and responsi-
bility for the whole of the investigations both for the
northern and for the proposed southern observatory;
and intended to go to the Southern Hemisiihere to
organize the work, to remain there for a time in order
to ensure its smooth, speedy, and accurate running,
and, towards the end of the southern series of
observations, to re-visit that observatory to satisfy
himself and colleagues that no point of importance
liad been neglected. In making his application for a
grant to carry out his plans of 1902, in their most
complete and satisfactorv manner, he specially drew

96

KNOWLEDGE.

March, 1911.

attention to. and emphasized, the fact that this
observational portion and its reduction to standard
points of reference, was both the most costly and the
most laborious" of the four items for investigation
proposed for the Institutior.'s kindlv interest and
pecuniary support.

The Board of Trustees of the Carnegie Institution
agreed to aid Professor Boss, and, under grant No.
479, £5,000 was appropriated for the use of the
Department of Meridian .Astrometry, to be directed
by Professor Boss at the Dudley Observatory.
Albany, New York, for " stiufy of iiiotion and
sfnictiirc of the stellar system of tlie Xorthern and
Souther II Hem isph eres . ' '

Work ujion this larger General Catalogue of about
25,000 stars, was commenced at Alban\" at the earliest
moment in 1907, October 7th, and by the end of
1908, August 15th, or after ten months' work.
10,421 meridian observations were obtained \\ith the
Olcott Circle. Thc\" were chiefly made by the two
assistants, Mr. A. J. Roy and Mr. W. B. Varnum,
whose zeal, loyalty, and efficiencw as Professor Boss
specially testifies, is \\'orthy of all praise. Eight others
have also assisted in the work at Albany. These
observations were made upon a fundamental s>-s-
tem, and are mostly of standard stars between 83"'
north zenith distance and 40" of south declination.
All the stars visible from the Alban\- zenith to
this south declination can also be observed at the
finally-adopted site of the southern observatory
at San Luiz, latitude — 33" 18' and longitude 66""3
or 4'' 25'" 25"" W. of Greenwich. So soon as
the favourable conditions of the climate were
ascertained, and it had been decided that San
Luiz, in .\rgentina, should be the site for the
southern observatory, progress was made with the
preparations for the establishment of the observa-
tory during 1907 and 1908. San Luiz is a town of
about ten thousand inhabitants, and is situated on
the Trans-Andean Railway, about five hundred miles
inland or west of Buenos Aires, and at an altitude
of two thousand five hundred feet above sea level.
The site is not near enough to the Andes to get
influenced by the intense and oppressive heat waves
of the Andean plains.

The U.S. Department of State, through the
courteous and cordial interest of the Secretary of
State, Mr. E. Root, was specialh" helpful in arrang-
ing matters with the Argentine minister. Senor

Don E. Portela, who interceded and induced the
Argentine Government to facilitate the choice of a
site, for various permissions, and for other privileges.

By the valuable influence, interest, and courtesy
of Mr. W. G. Davis, Director of the Meteorological
Department in Argentina, Dr. L. S. Rowe, Mr. De la
Plata. Mr. Naon, and Mr. Ezcurres, Ministers of
Foreign Affairs, of Justice, of Pulilic Instruction,
and of Agriculture respectively, they were saved
much trouble and expense in the entry of the
instruments, in their free conveyance to San
Luiz, in free tickets for the observers, and in the
free use of a site on national propert\- of the
Escuela Regional (San Luiz). which is under the
direction of Dr. C. L. Xewton.

So the Argentine authorities — especiall\- those at
San Luiz — having entered thus heartily into the
matter, it was possible for Professor Boss, with
Professor R. H. Tucker and Mr. W. B. Varnum, to sail
in the SS. Velasquez, on August 20th, 1908; they
arri\'ed at Buenos Aires on September 13th, and at San
Luiz on September 20th, where they were met by a
party of official representatives of the Provincial
Govermnent of San Luiz, consisting of Senores
Gazari, Ouiroga and Romanella, and bj' many
prominent citizens of San Luiz. Professor Boss and
his colleagues at once proceeded to choose the actual
site at San Luiz, to select the quarters for the
observatory staff, offices, and so on, and to make
general arrangements for the woik. Certain instru-
ments and portions of some of the constructive
materials were taken out there by these astronomers.
As soon as the ground could be prepared, and the
construction of the observatory had been planned and
started, Professor Boss returned to Buenos Aires
on October 7th. leaving Professor Tucker and
Mr. X'arninn to take charge and superintend the
erection.

On October 10th, Professor Boss sailed in the
SS. Wiasi/uez on his return to New York, On the
sixth da)' out the ship ran at full speed upon the
rocky coast of San Sebastian Island ; the night was
very dark, with rain and fog. The ship and its
cargo became a total wreck, but after some dangers
and hardships, all the passengers, crew, and most of
their luggage were saved, and the\" proceeded to
Santos, Brazil, from which jiort Professor Boss
again started, in the S.S. Titian, for New York, on
No\-ember 1 1th.

f To he eontinued I.

RKLSSNER'S FIBRE.

At a recent meeting of the Linnean Society of
London, Professor Dendy and Mr. G. E. Nicholls
exhibited a series of lantern slides illustrating the
structure and relation of the sub-commissural organ
which has a sensory function in brains of various
vertebrate types as well as of Reissner's fibre
which runs from the sense organ down the spinal
cord. The slides were described by Professor

Dend\-, while Mr. Nicholls gave a brief account
of some experiments which he had made, which
so far seemed to support the view that the
organs in question constitute an apparatus for
automatically regulating the flexure of the long
axis of the body. Reissner's filire does not
apparently exist in man, though some traces of
the sub-commissural organ occur in the embryo.

THE SPARROW" HAWK (Accipitcr nisiis).

I II iistiiit(.cl from Pli<)t<);^r,iplis

ISv ARTHUR BROOK.

Nest and Eggs.

\iiiiiii; ill tlif Nest.

A nearly-fledged Bird.

The Hen on the Nest.

97

NESTING

SITES '

EOR BIRDS. "^

The boxes at the top of
the page are on the same plan
as those which have been nsed
with great success in the Brent
N'alley Bird Sanctuar\-. but
some improvements ha\e been
made in the way in which the
hd opens and is fixed in place.

The boxes seen in the middle of the
page are hollowed out from natural logs
of the Birch, the tops can be removed
so that they may be cleaned out or the
contents examined from time to time.

The others shown at the bottom of
the page are also made from natural
logs, but in this case the centre is
removed from the side instead of from
the end. and after being hollowed out
a second and a third time the piece is
replaced once more in the log from
which it can be pulled out like a drawer.

98

THE ENCOURAGEMENT OF INSECT FATING BIRDS.

Although here and there in this countrN' those
who are fond of birds have furnished them with
nesting sites, whicli is an important point in these
days when it is not eas\' f(>r many species that build

find accommodation, ^•et

reneral

m holes to

attempt has been made as in some other countries
definiteh' to encourage insect - eating birds,

which are specially use-
ful to those who are en-
gaged in growing crops.

Figure 1.

The parts of a box made from a log so arranged
that the top lifts off.

The Brent \'alley Bird Sanctuary Committee
have sho\\n what can be done in the way of
protecting birds on the borders of London,
and with a view to making the mo\'ement in
favour of attracting birds more general, they have
introduced and are showing at various exhibitions

<.)f nesting sites with

The nesting sites made from
used with great effect in the Sanct
that in gardens and near
houses it might be advis-
able to use materials
which are more natural
and less suggestive of
a trap. The ordinary
boxes made from lo.tjs

details of their construction.

boards have been

•. but it seems

Figure 2.

The parts of a nesting site in which the centre
of the log can be drawn oat.

of which the tops come off. can easily be erected on
posts, and are suitable for wrens and tits when the\-
have a small opening, and for robins when the
aperture is a little bigger. The latter birds some-
times prefer a liox with an open front, and this is the
case with fl\catchers. \'arious boxes have been

Figure 3. Figure 4.

Two simple forms of open nesting bo.xes for birds which do not care to build in complete darkness,

but which like protection from the rain.

a number of new designs for nesting boxes.
The Chairman of the Committee has contributed
an article on the subject to The Country Hume
for March, and here and on the opposite page we
give illustrations of some of the more important kinds

designed for their benefit (see Figures 3 and 4), and a
moctitication of Figure 2 of which the upper half of
the front of the movable piece has been cut right away.
All particulars can be obtained from the Secretary of
the Selborne Societv, at 42, Bloomsbury Square, W.C.

99

THE FACE OF THE SKY FOR MARCH.

Bv \V. SHACKLETOX, F.R..A.S., A.R.C.S.

The Sux. — On the 1st the Sun rises at 6.49 and sets at 5.37;
on the 31st he rises at 5.42 and sets at 6.27. The Sun enters
the sign of Aries at 6 p.m. on the 21st, when Sprin.s; com-
mences. Small groups of spots may usually be observed on
the Sun's disc, but there has been a considerable falling off in
solar activity, both as observed visually and spectroscopically :
at the time of writing one small spot is visible. The positions
of the Sun's axis, centre of disc, and heliographic longitude
are given below : —

Venus :

Date.

.Axis inclined
from N. pi>iiit.

Centre of l)i>c
S. of

Heliographic
Longitude of ,

Sun's Equator.

Centre of Disc.

.Mar.

-,

21"

48' W

t 14'

224'

24'

7 ••■

22°

58'VV

f 15'

.58°

3^'

12 .

23"

59' W

7° .3'

92°

3K'

17 ...

-•4^

49'W

r 7'

2fa°

44'

"

22 ..

25°

29' VV

6" 58'

y-o°

49'

,,

27 ...

25"

59' \V

6= 46'

254=

jj

Apl.

I

26°

iS'W

6' 31'

i8S°

56'

fa .

26'

26 AN

fa- 13'

[2 2^'

58'

The Zodiacal light may be seen in the West, shortly after
sunset. After the middle of the month is the best time for
observation, as the Moon will not have risen, and the tapering
glow may be seen for 30 or 40 degrees along the ecliptic.

The Moon : —

Date.

Pha.se.s.

H.

M.

Mar. 7 ...

., 14 ■■
„ 23 ...

■ ■ 30 .
Apl. 6 .

.Mar. 6 ...

., 21 ..

Apl. 2 ..

I

(I
•

Fir<^t Quarter

Full Moon

Last Quarter ..
New Moon
First Quarter .

1 1

1 1

0

0

5

2 p.m.

59 P-m-
26 a.m.
38 p.m.
55 a.m.

Perigee...

Apogee

Perigee ..

4
I
8

30 p.m.
6 p. m.
12 a m.

OCCULT.^TIONS. — The following are the principal occulta-
tions visible from Greenwich : —

Date.

St.'ir'.s

_ij

Disappearance.

Reappearance.

Angle

.\ngle

Mean

from N.

Mean from N.

7c.

Time.

point.
E.

Time. , point.

' E.

p.m.

a.m.

Mar. 6

A^ Tauri

4-5

M..57

71"

0 47

p.m.

270"

,. 7

/: I auri

s-^

8.S2

88"

9-57

260"

, to

oil Cancri

6-1

5.58

32"

6-7

343"

10

cj- Cancri

0'2

5.46

■05"

6.i;8

272"

THE PLANETS.

Mercury

—

Date.

Right .Ascension.

Declination.

.Mar. I .

',! 21 ...
,. 31 ■

.Apl. 10 . ,

!.. m.

21 50

22 55

0 5

1 16

2 20

S IS" 22'
9° 8'

''' "" 53'
\ 8" 50'
N 16" iS'

Date.

R

ght Ascension.

h.

ni.

Mar. I ...

0

ID

11

0

55

21 ...

I

40

;t

Apl. 10 ..

3

15

Declination.

,*.;

0"

3

N

J

8'

lO"

8'

14^

44'

N

1 8-'

45'

Venus is an evening star, and may be seen immediately after
sunset, looking \V., not very hi.gh abo\ e the horizon. Through-
out the month the planet sets
about 2i hours after the Sun.

In the telescope the planet
appears gibbous, about 0-9 of
the disc being illuminated.

On March 2nd, the Moon
appears near the planet, V'enus
being 2° 20' to the North, but on
April 1st. the two appear in still
closer proximity as shown below.
Venus at 5.45 p.m. being only
14' to the North. The Moon
will be only two days old, but
if the weather is favourable it should be easy to see both
the planet and Moon, quite early on in the twilight.

M.\RS : —

Date.

Right .Ascension.

Declination.

Mai. 1

,. I i ...

., 21

,. 31 ■■■

.Apl. 10 ...

h. m.
iq 30
20 2

20 33

21 3
21 33

S 22° 34'
21^' 24'

19° 53'
18° 3'

S r5-' 55

Mars is visible for a short time in the early mornings, rising
about 4.30 a.m., near the middle of the month. The planet is
an inconspicuous object in Sagittarius, and is ill-suited for
observing telescopically, as the apparent diameter is about
5". The Martian equinox occurs on March 7th, when Spring
commences in the Southern Hemisphere.

Jupiter : —

Date.

RiL;ht .Ascension.

Declination.

Mar. I ...

h. m.

14 50

S 14" 5S'

,, II .
„ 21
,, 31 ...
Apl. 10 ..

14 4q
14 4S
14 45
14 41

14" 54'

14" 44'

14° 29'

,S 14° It'

Mercury is in superior conjunction with the Sun on the 20th,
and is thus unobscrvable throughout the month.

Jupiter rises in the E.S.E. at 11.30 p.m. on the 1st and at
9.25 p.m. on the 31st; is the most conspicuous object in the
late evening sky looking East. The planet is describing a
retrograde path in Libra about 1° N. of a- Librae. "The
.ittcndant bright moons can be seen in very small telescopes
or even in a pair of binoculars magnifying 6 or 8 times,
whilst the belts are also visible in small telescopes of about
two inches aperture using a magnifying power of about 50.
The equatorial diameter of the pl.tnet on the 19th is 41"-5.

100

M.\RCH, 1911.

KNOWLEDGE.

101

whilst the polar diameter is 2"' 7 smaller; this polar Hatteniiifj
is readily observed in telescopes powerful enontjh to see the
belts.

In larger telescopes, markings on the belts may be observed;
these rotate with the planet and recur in the same position
every 9*' 55" which is the planet's rotation period.

The following table gives the satellite phenomena \ isible in

this country before midnight :-

-

5

'

0

c

0

P

■» 1 P.M.V
y; a. H. M.

V

1

S P.M.'s.

S H. M.

d

0

tr.

.=

P.M.\.

II. M.

Mar.

Mar.

Mar.

8

I. ,Sh. K. II ,7

2^

1.

Ec. I). 10 34

ji

1.

Sh. I

0 34

i6

I. Oc. k. II 40

24

1.

Tr. E. 10 40

1.

Tr. 1.

21

II. Tr. I. II --.o

30

11.

Oc. R. 10 56

3"

1.

Sh. K.

II 4n

'*0c. D." ilenotes the fii.sappearaiice of the SalelHle liehind the disc, ami
"Oc. R." its reappearance: " Tr. I." the ingress of a transit across the disc, and
"Tr. E." its egress ; " Sh. I." the ingress of a transit of the shadow across the disc
and "Sh. E." its egress; " Ec. D." denotes disappearance of Satellitt: Ijy Eclipse_

Saturx : —

Date.

Right Ascension.

Declination.

Mar. I ...

., 16 ...

Apl. I ..

ll. 111.

2 5
2 1 1
2 iS

X ID'' 16'

10" 4q'

N 11" 2S'

Saturn is only observable for a short time each evening
during the month, as he sets at 10.28 p.m. on the first and at
8.45 on the 31st. The planet appears as a fairly bright star
looking nearly due West as soon as it is dark. Observed in
the telescope, the rin.g appears wide open, as we are looking on
the Southern surface at an angle of 1S\ The apparent
diameter of the outer major and minor axes of the ring are
39" and 12" respectively, whilst the diameter of the ball is 15".

The Moon appears r.ear the planet on the evenings of the
4th and the 31st, whilst Venus appears in proximitv on the
29th.

L'R.ANUS: —

Dale.

Right Ascension.

Declination.

Mar. I ...
Apl. 1 ...

h. 111. 5.

19 59 36

20 4 34

S 21'- 7 1 3"
S 20'- 53' 4S"

Uranus is visible in the early morning, rising about 4.15 a.m.
near the middle of the month.

Neptune ; —

Date.

Right AsceiLsion.

Declination.

Mar. I ..
Apl. I ...

ll. 111. .<;.
7 - 1 56
7 -0 55

N 21" 2S' 45"
N 2 1 •' 3 1 ' 41"

Neptune is situated in Gemini about fhree-and-a-half
degrees S.E. of the star S Geminoruni.

Near the middle of the month the planet is on the meridian
about 7.45 p.m., and sets .about 3.45 a.m. The planet is
diflicnlt to identify among the numerous small stars appearing
in the same field of view, and as he is practically stationary
this month he cannot readily be detected by his relati\ e
motion. Moreover, it requires a high power (about 300) and
.good definition to distinguish his disc.

Meteor Showers: —

Date.

Radiant.

Near to

Charactej i^tics

R.A.

Dec.

h. m.

Mai. 1-4 114

„ 14 ... 16 40

24 ... 10 44

+ 4
+ 54-'
+ 58"

T I.eoiii>
fi Draconis
/3 Ursae.Maj

Slow : bright.

Swift.

Swift.

Minima of .Algol occur on the llth at 10.21 p.m., and on
the 14th ,it 7.10 p.m. Its period is 2^ 20'' 49'", by which other
iiiininia may lie deduced.

Double Stars. — 7 Leonis. X.'' 14'", N. 20" 22', mags. 2, 4;
separation 3"-S. In steady air. the prime requisite for double
star observations, this double m.ay be well seen in a 3-in.
telescope with an eyepiece magnifying about 30 to the inch of
aperture, but on most nights one with a power of 40 is better.
The brighter component is of a bright orange tint, w hilst the
fainter is more yellow.

1 Leonis XI." 19"", N. 11 5'. mags. 4, 7*; separation 2"-2.
A pretty double of different-coloured stars, the brighter being
yellow, the other blue. This object requires a favourable
night and a fairly high power on small telescopes.

a Leonis iRcf^nlits) has a small attendant about 180"
distant, magnitude 8-5, and easily seen in a 3-inch telescope.

a Canuin \'enat (Cor Carolil XII.'' 52"', N. 38= 49', mags.
2-5. 6-5, separation 20". Easy double; can be seen with
moderately low powers, even in 2-in. telescopes.

CORRESPONDENCE.

COLOURS OX THK ECLIPSED MOON.

Tv titc Edit,,

)f " Knowledge."

Sirs, — I think I remember a recent question in " Know-
ledge " to this effect : " What would be the distance of
the red light from the sun refracted through the earth's
atmosphere, regarding this as a lens stopped down by a large
central circular disc," and I think this had reference to the
colours on the surface of the moon in eclipse. Now the
action is quite unlike that of any lens because the density of
the air diminishes from the surface upwards. Regarding the
sun as a point of light, the focus for red rays passing close to
the surface of the earth would fall at a point somewhat
nearer than the moon's distance, and the difference of position
for any other coloured light would be very small, but the light
which passed through the outermost layer of the atmosphere
would fall only just inside the vertex of the earth's geometrical

conical shadow nearly a million miles awa\-. and at every
point between these extreme distances there would be a focus
of some infinitesimal fraction of the light ; moreover, the sun is
not a point and the question is still more vague. The light
which passes through the earth's atmosphere would cover a
surface which, at the distance of the moon, would be very
much larger than the moon's disc ; the distribution of the light
over this surface would not be uniform, and would be very
slightly different for different colours, but this could not possibly
produce any recognisable colourdifference ; the colours observed
are due to a cause quite distinct from refraction. The green
colour often noticed at the edge of the shadow before and
after totality is no doubt due to the familiar subjective
complementary colour-effect of the reddish light in the shadow,
and the coppery colour in the shadow is due to the same cause
which gives us a blue sky and a red rising and setting sun,
namely, that light of short wave-length is much more reflected

102

KNOWLEDGE.

March, 1911.

and scattered by small particles in the air — or according to
Lord Rayleigh, by the molecules of the air itself — than the red
rays with greater wave-length : and the light which reaches the
eclipsed moon has passed through a depth of air about twice
as great as that through which the light from a setting sun has
passed.

The very great differences in the brightness of the eclipsed
moon on different occasions is very curious, and though clouds
over large surfaces on the earth might well cause considerable
differences in the light, it seems hardly sufficient to account
for it entirely. I H r

.A.RTli'ICI.\L MOCK SL'XS.
To the Editors of " Knowledge."

Sirs. — .-^t the end of November I had a view of four mock
suns, and glimpses of five others, all, however, produced by a
chance arrangement of windows. 1 was seated in a train
tra\elling west along the north shore of the Lake of Geneva :
it was between 2. JO and 3 p.m.. and the low sun shone straight
into the carriage.

There were three panes of glass between me and the outer
air — viz.: (a) the glass window of the carriage; (61 the glass
window of the corridor, distant about two-and-a-half feet
from dr) : and. between these (cl the window of the carriage
door, which, being open and folded back, was about an inch
distant from [a). On either side of the sun, and distant about
five degrees, there appeared fainter, but still very bright, sun-
images. Beyond each of these again, at the same distance,
were faint sun-images. When the carriage was slightly tilted
on a curve, fainter images were seen above each of these five
suns, ten suns in all. The phenomenon was not visible from
the corridor, and was pretty clearly caused by a reflection
between the near panes ((7) and (c). How far is this analogous

to the mock suns of Polar explorers ■ , ,, .. r-r- t-i>i-

^ AGNLS FK\.

THK ETERNAL RETURN.

To flic Editors of " Knovvlkdgh."

Sirs. — In reply to your correspondent. Mr. H. D. Barclay.
re the theory of Nietzche. I would suggest that much depends
upon the meaning attached to the words "identical individual."
( )ur identity consists of the consciousness of the continuation
of our psychic reality, notwithstanding repeated entire material
changes and replacings of our bodily organism. The inde-
structibility of the material constituting the organism is a
possible conception, as also its adaptability to new combina-
tions: but to assume that a re-combination of the precisely
same elements will constitute the same being, is to assume
that the identical psychical entity is not only dependent
upon, but is ahsolutelv produced by, that particular
combination.

This is to grant eternity to matter, but to make the actual
existence of mental phenomena subject to creation and
destruction. .Again, many misleading words .are used in
reference to force. To speak of the " sum total of force " is
to give it "reality," to constitute it a tangible entity, having
dimensions and duration, a power real and potent to move
inert matter. But we know of no such force. "Matter and its
activities" is the limit of physical science, force is the name
of those activities. To give it occupation in space is to create
it matter; "to pervade infinite space" is to exclude the
possibility of other existence.

Mr. Barclay, I venture to think, is right in affirming that
absolute vacant space seems unthinkable, though this may be
so "in the absolute." Vacant space is not only thinkable, but
an essential concomitant to material existence.

May we have better elucidations of this most interesting

subject from more cap.able pens ?

FRED OILMAN.

.S()L.\R I)I,STrRr..ANCES DlIRIi\(i J.XNUARY, 1911.
By FRANK C. DENNETT.

Thk great tailing ott in the number of outbreaks upon the
solar surface was very marked during January. With the
exception of the five days, the 4th, 5th, 17th, 21st and the
22nd. the sun has been examined every day. Upon the 19th,
20th, 25th, 27th and the 2Sth no trace of disturbance, bright
or dark, could be found. On ten other dates faculae alone
were to be seen. The longitude of the Central Meridian at
noon on January the 1st was 294" 30'.

No. 1. — \ spot first seen near the east limb on January the
3rd. There appeared to be two umbrae on the 7th, the larger
being again cut across by a bright bridge ; two pores were
situated just behind it. One pore still there on the 8th, and
the umbra bridged. On the 10th the bridged umbra seemed
of a violet hue, and the filamented penumbra appeared to
brighten inwards. The bright fringe, especially on equatorial
side, still seen, as well as the bridging, on the 13th and the
14th, when the spot was evidently dwindling. On the 15th.
when last seen, still bridged, the umbra seemed to be edged
with brightness, but a penumbral wing stretched south-east.
The greatest diameter of the spot was 15,000 miles. As it

neared the western limb it became surrounded by faculae.

.\ group of faculae. A, like a companion outbreak to No. 1,
seen on the 14th.

B and C. faculic ridges seen on the 14th-15th round the
eastern limb, the latter seen again the 2 5th-26th, when
approaching the western limb.

D. a small bright taenia near the western limb on the 25th.

Near the eastern limb on the 25th a bright ridge, E, recorded.

A small faculic knot in a disturbed area, F, seen on the 31st.

This great falling oft' in the number of outbreaks seems to
indicate that we are approaching the time of solar minimum.
As one cycle ends the spots are as a whole nearer to the
equator. The new cycle is usually indicated by the outbreak
of spots far away from the equator, so that it is necessary to
watch the outer boundaries of the spot-zones. It seems
probable that the signs of returning activity may be noted in
the northern zone.

The chart is constructed from the combined observations of
Messrs. J. McHarg, A. A. Buss, E. E. Peacock, W. Strachan,
and F. C. Dennett.

DAY OF lANUARY.

^'

22 ^1

20

19

?

'("

'1^

1%

K

13

1

II

10

C

?

7

6

5

4 3

. 5

3a

Z9

1. 23.

< '

J7

1

et

2,5

'♦

T.

■ V

"ST

30

6l;

1

'n

"c

"\E

B

»

oV

0
F

A

^i.

^0

M

r.cD

k

0 10 20 50 40 50 60

90 100 110 \}0 150 140 150 160 irO ISO 190 :00 ?I0 2J0 230 J40 250 260 270 280 2=10 .300 310 320 iW W> -"SO 360

QUERIES AND ANSWERS.

Readers arc invited to scinl iii (Jiicstioiis ami to answer the Queries icliieli are printed on this paf<e.

QUESTIONS.

Numbers 16, 17 and IS (December number, page 4611,
21 (January number, page 39), 26 and 27 (February number,
page 49). still remain unanswered.

28. P.\LL.A.S .\ND d .A-OU-^RII.— On September 22nd last,
at transit time, (a moderately good night, and Pallas being then
of 9-1 magnitude), the Planetoid was quite mysterionsly
missing to the writer in the immediate neighbourhood of
d .\quarii. Owing to bad weather and moonlight it had last
been observed only on the 13th. and was again recovered on
the 24th. As it had obviously closely approached d Aquarii
would some one of your astronomical readers care to very
kindly give me its position-angle and distance from the named
star at transit on 22nd September, or, failing that, either the
apparent place for the date of the star, or a 1910 mean -place ?

I should also feel very grateful for particulars of the magni-
(■ude, distance and position-angle of the small companion of d.

Asteroid.

29. CONSTITUTION OF THE ATMOSPHERE IN
WINTER. — .\s deciduous trees and plants do not elaborate
O, nor consume CO.> during the winter, have any experiments
shown that there is a deficiency of O, or a preponderance of
COj during this season ? ,,.11

30. FINDING THE TIME BY THE HEA\-ENLV
BODIES. — I have been much interested in the recent
correspondence on finding the time by night through obser-
vation of the stars.

Might I ask whether any of your readers can go further and
inform me on the following problems connected with the time
by day ?

(1) How can the time of the day be ascertained by

measuring the ratio of the length of a stick to that
of its shadow ? As an example, imagine this ratio
to be one-half on May 1st, what is the time ?

(2) .At what times in the year will the length of a stick be

the same as that of its shadow at noon ?

In both instances I assume the latitude of London.

(3) Can the latitude of a place be determined by comparing

the ratio between the length of a stick and that of its

shadow at noon ? ,^ ^ „„„._„,

Interested.

31. WIRELESS TELEGRAPHY AND THE WEATHER.
— I have heard it stated that wireless telegraphy may be, to
a certain extent, responsible fur changes in weather. Can
any scientific reason be given for this if it be true ?

JoHX Glas. SA^■DE^rA^•.

REPLIES.

10. WATER AND ITS OWN LEVEL.— Are not the
difficulties of G. G. B. and Mr. A. Mercer referable simply to
their neglect to define to themselves the meaning they attach
to the expression " its own level " ? The latter correspondent's
suggestion is that the surface of a small area of water may
possibly be ftat, whereas the truth is that, eliminating all
extraneous forces (such as centrifugal force, solar and lunar
attraction, winds, and — in minute wet surfaces — globular and
capillary attraction), no water-surface, however small, can
possibly be flat. In other words it can never be tangential to
any spherical surface, but must be itself an actual part of a
spherical surface, and of a curvature appropriate to its radial
distance from the Earth's centre. Conseciuently, that which
the surface of any body of water — if disturbed — does again

seek is "' its appropriate spherical curvature " ; and if the word
'' level " be assumed necessarily to mean a plane surface then
the whole expression " Water finds its own level " must be
considered not only unscientific but directly untrue.

If the above statement of theory be accepted the following
occur to me as some of the more curious of the necessary
results : —

If the rotation and revolution of the Earth were suddenly
stopped (again we must eliminate external gravitational forces,
as also the moment of inertia), the equatorial oceans would
immediately flow away northwards and southwards, in an
attempt to reduce the spheroidal wet surface of our globe to
that of a true sphere.

.Again, under existing circumstances, the surface of the
Dead Sea is no less than one thousand two hundred and
ninety-two feet below that of the neighbouring Mediterranean.
Consequently, being part of a sphere of lesser radius, any
circular acre (say) of the former sea will have a wholly
difterent surface-curvature from that of a circular acre of the
Mediterranean, and — sequentially — a lesser right horizontal
diameter.

Much more markedly will a given area of ocean in equatorial
regions differ from the same in polar regions.

More strikingly still follows this fact, that any particular
portion of the ocean-surface must have different curvatures,
even at high-water and low-water respecti\ely ; and
consequently that the tables for calculating horizon-dip and
distance given in such books as "'Chambers' Tables" and
" Molesworth's Formulae " can only be averages or approxi-
mations, since they can only strictl\- be true for one latitude
or one state of the tide.

Lastly, one has, of course, to admit that the surface of a
stationary cup of tea varies momentarily, owing to the lunar
and solar tides caused in it. But what seems to me to require,
perhaps, even a larger degree of imagination, is to realize that
the surface of the liquid must undergo a continuous alteration
of curvature even as one raises the cup from the table to

lips.

W. E. Yerward- James.

13. THE FINDING OF THE TIME AT NIGHT.— To
find the time at night without instruments or notes of any kind,
it is necessary to acquire the faculty of estimating, by eye, the
distance in time of any star from the meridian.

The imaginary arc representing the latter can be readily
conceived by reference to the Pole Star. Having determined
the first-named element the remainder is a simple question of
Right .Ascensions (R..A.).

Commit to memory R.A. of a very few conspicuous stars
and learn to recognise them at sight.

The R.A. of the Sun is still easier, it being only necessary to
recollect that it starts from O'' O" at the vernal equinox,
March 22ud. and increases two hours per month till the annual
round is complete at twenty-foiu' hours.

Proceed as follows : —

R..A. of star + or — time from meridian = R..A. of Latter.

R.A. of meridian 4- or — R.A. of Sun = time.

Example, January 5th, 1911.

Sirius in S.E. quarter, apparently 3'' 30"' E. of meridian.

R..A. of Sirius ...
Deduct ...

40"
3" 30"

R..-\. of meridian 3''
R.A. of Sun deduct

10"'+ 24"

19"

10"
0"

Time = S" 10'" p.m.

Edmun'd Rourke. R.K.

103

104

KNOWLEDGE.

March. UHl.

13. THE FINDING (.)1' THi: TIME .\T NIGHT.—
In the note by K. H. M. K. in the January number, in the
diagram of the dial a IV was misprinted for \'l. and for the
benefit of our readers who may be wishful to use it we insert
an amended illustration.

Polaris and /J Ursae minoris.

1 Jan. 1 July
1 Feb. 1 Aug.
1 Mar. 1 Sept.

VIII

\T

IIII

1 Apr. 1 Oct.

1 Mav 1 Nov.

1 1 Jun. 1 Dec.

II

XII

X

14. WHICH IS FASTEST— SIGHT OR HEARING?—

This (luestion is somewhat indefinite. In any practical case

c.i>., the sight and sound of an electric spark, the relative

\elocities of light and sound make it certain that the retina

will be aftected earlier than the ear drum, but it does not

necessarily follow that the consciousness of the light will

precede that of the sound, though it will certainly be so if the

spark is distant by more than a very few inches. If the

question is which can produce the quickest physical response,

it is practical and interesting, and can be made the subject of

experiment : in this case, the relative intensities of the light and

the sound are an important factor, and results with different

indi\ iduals varv considerablv. , ,, ,~

J. H. (j.

22. RADIUM. — The ratio given on page 4'! of Railinni to
Uranium should read 3->S x 10~'.

2.T. THli TIDES. — Mr. Hardcastle in a reply to a <iiiei\'
of mine has, unaxoidably. as I quite see, from the wording of
the question, misapprehended uiy object. The question was
suggested by the pages in Darwin's "' Tides," pages 240-242,
to which he refers me. and I purposely did not mention
Darwin or carry the question a stage further ou, because I
wanted to elicit an independent answer and, if possible, one
independent of the mathematical fictiou of considering free
wave and forced wave motions in a single wave as separate
entities. A word about this "' fiction "' later.

Adopting this fiction, it seems to me that a mental picture
of the way in which friction comes in and its direction, is much
more easily formed (the free wave tendency being continuously
destroyed by the friction) tlian if the wave forui is considered
as simply due at each moment to the combined action of lunar
force and gravity together. Now I imagine that Darwin
deliberately elected to avoid the fiction as possibly liable to
produce misconceptions in anyone new to the subject and
probably without mathematical knowledge. With the attempt
I feel every sympathy, but it creates, I think, more difficulties
than it avoids. There seeiu to me points in his presentment
of the subject which to a novice will appear shadowy or even
false. Moreover, I am doubtful whether he has really avoided
the fiction, and he has uiade his argument more difficult to
follow by unconsciously omitting a step (or half-step; the
principle has been explained earlier). At one point a
student will almost invariably ask, "How can a change in
the depth of the ocean suddenly reverse the action of the
friction?" and I think the answer would implicitly involve
the use of the tabooed fiction. To take only one point,
which point, however, forms the basis of the whole
argument, on page 241. " When, as in reality, the
lit|uid is subject to friction, it gets belated in its rhythmical
rise and fall, and the protuberance is carried onwards by the
rotation of the planet beyond its proper place." Now the
reader will very likely argue that friction would cause moving
particles to come to rest sooner, and therefore the rise and
f.ill would be accelerated, and the tidal prominence would fall
behind instead of in front of the moon, and I certainly think
that failure to see furtlier into the matter would not indicate
want of intelligence. Perhaps this may seem hypercritical,
and it is impossible to detune strictly what constitutes a
/)o/i;(/<n- explanation ; in general terms I should define it as
one which gave the reader a clear mental picture of what was
going on, without suppressing difficulties in the principles
applied. With regard to the latter point I need not say about
a book so widely known, how singularly free in general it is
from this weakness, and perhaps this is the only case
(probably the most difficult of those set for explanation),
where I should feel inclined to criticise the trcatuient as not
(|uite satisfactory.

With reg.ud to the "fiction." it is in reality no greater
than that of identifying a force with two components into
which it may be resolved, .and is in fact, under more complex
conditions, identical with it ; but I certainly think that a
student beginning the study of dynamics should be eucouraged
to regard the kinematical parallelogram law, when applied to
dyuamical problems, in the light of an hypothesis, to be
N'erified by finding that in e\ery sort of combination it leads
to consistent results and is alwavs confirmed b\- experiment.

J. H. G.

THE ANCE.STRV ()!■ JJIJAIESTIC CATTLE.

At a meeting of the Zoiilogical Society of London, held on
February 7th, Professor J. Cossar Ewart. F.R.S., gave an
account of some skulls of oxen from the Roman station at
Newstead, Melrose. The evidence which he had obtained
was against the descent of all European cattle from the Urus
i/ios priiiiigcnius) as well as of that of all European, Indian,
and African breeds from the Asiatic Urus (B. iiomadiciis).
His conclusions are as follows: —

1. That the Celtic Shorthorn (Bos loiii^ifroiis) is probably
more intimately related to the Zebu of India (Bo.s
iiidicKs) than t(.) the European Urus iBos /)/•/;;; /,i;c;n//i- 1.

That long premaxillae are usually correlated with an
occiput of the Bos priinigeinus type, while short
premaxillae are usually correlated with an occiput of
the Bos aaitifrons type.

That polled black Gallowa\' cattle and polled white
"wild" Cadzow cattle are intimately related to the
Urus, that flat-polled Aberdeen-Angus cattle probably
include amongst their ancestors an ancient Oriental
race now represented by, amongst others, a Syrian
breed with rudimentary horns, and that round-polled
cattle may belong to a still more ancient Oriental race
descended from Bos aciitifrons of the Punjab Siwaliks.

NOTES

ASTRONOMY

By A. C. D. Crommelix. D.Sc.

NO\"A LACERTAE. — The visible existence of Nova
Lacertae, before its outburst, noted as possible by Mr.
Bellamy last month, has now been fully verified. Professor
Wolf has measured plates taken in 1904 which give the
position (referred to the equinox of 1900) Right Ascension
22" 31"" 44"-99 North Declination, 52° ll' 55"-9. His plates
of the present year give Right Ascension O^-IO greater,
and Declination 0"-l greater. Professor Barnard has also
identified the object on plates of his. taUen in 1S93. 1907 and

1909. He has also measured these plates, finding the position
practically identical with that of the present year, thus leaving
no doubt of the identity of the object, and showing that its
proper motion is small, which we expect to be the case with
Novae, from the fact that they always appear in or near the
Milky Way, and are. therefore, very remote. The magnitude
before the outburst was twelve-and-a-half according to
Wolf, fourteen according to Barnard. It would not.
therefore, be visible on plates taken with a short exposure,
which probably explains its absence on the plates taken
at Harvard on November 19th last, and on earlier dates.
This is, I believe, the first occasion on which a Nova
has been certainly identified with a visible pre-existent
object: of course, the probability of doing so increases as the
storehouse of plates grows larger. But this is not the only
reason, for plates of the Nova Persei region were in existence.
and failed to reveal any trace of it. It is evident that that
outbreak was on a grander scale than the present one, for it
sprang up from the fifteenth magnitude !or fainter) to the first,
while this has only risen from the fourteenth to the fifth. It
will be interesting to see whether it declines to its former
magnitude, or remains permanently brighter. Professor
Barnard notes a peculiarity which it shares with Nova
Geminorum, viz.. that it has two distinct and sharp foci,
one at the ordinary focus, the other eight millimetres further
out. and due to the great brilliance of the crimson H (alpha)
line of hydrogen. The Nova has been steadily declining
since the outburst ; its light fell off during December from
the fifth to the seventh magnitvide, and by the end of January
it was about eight-and-a-half. Its circumpolar position will
enable it to be continuously kept in view during the decline
of its light.

THE SPECTRUM OF MARS.— Astronomers will remember
Professor Campbell's expedition to the top of Mount Whitney,
in the endeavour to obtain evidence of the presence or otherwise
of water-vapour in the atmosphere ot Mars. He has now
approached the problem in another manner. It is many years
since the shift of lines in the solar spectrum due to rotation
was used to distioguish solar lines from those that had their
origin in our atmosphere. Great dispersion was necessary,
owing to the slowness of the sun's rotation. In the case of
Mars, an equal dispersion is unattainable, owing to the
faintness of the spectrum, but the relative velocity is much
higher. Professor Campbell and Dr. Albrecht, took a series
of plates with a specially designed grating-spectroscope in
January and February, 1910, using plates rendered sensitive to
the red-end, where the water-vapour band is situated. After
careful examination of the plates they state that the amount of
water-vapour in the planet's atmosphere on February 2nd.

1910. was certainly less than one-fifth of that in the air above
Mount Hamilton at the time. The amount of oxygen in
Mars' atmosphere was also relatively small. These results
are only what we should expect, for it is obvious, both from
the planet's small mass, and from the great distinctness with
which the markings are seen, that its atmosphere is very much
Hirer than our own. Those who deny the existence of water-
vapour in its atmosphere are driven to adopt the conclusion
that the polar caps, and the occasional presence of cloud and
mist, are due to some other substance, such as carbon dioxide.

HALLEY'S COMET is still under observation, and is
being assiduously followed by Professor Barnard with the fortv-
inch Verkes" Refractor. It is now of the fourteenth magnitude,
round, 32" in diameter, slightly condensed, but without a
visible nucleus. It is considerably further from the Sun than
when first photographed in August, 1909, and yet is two
magnitudes brighter, showing that the physical brightening at
perihelion persists for some time. Professor Bani;-"' ''nt;
hopes of keeping it in view till the end of the year ; it ■.
be far outside the orbit of Jupiter, which it will cross i;, .>(,i„
next. It will remain invisible for seventy-four years, and will
probably be detected in August. 1985. passing perihelion about
February, 1986.

D'ARREST'S COMET was still in view at the end of
January, being seen by M. Gonnessiat at Algiers on January
22nd. when it was of magnitude fourteen-and-a-half. The
Paris Observatory has recently lost by death M. G. Leveau,
whose name is especially associated with this comet, from the
laborious care with which he has followed its movements ever
since 1864; the large perturbations by Jupiter render the work
difficult, but nevertheless his predictions have been extremely
e.xact, extending even down to the present return. He also
constructed tables of the minor planet Vesta, by which its
motion can be calculated with greater con\enience and
accuracy than by the method formerly employed.

BOT.AXV.

By Professor F. Cavers, D.Sc. F.L.S.

IRON BACTERIA.— Molisch has recently published one
of his excellent monographs (Fischer. Jena ; M. 5), the latest
production of his prolific pen being an important summary of
his own work, continued for eighteen years, as well as that of
other investigators, on this interesting group of bacteria. Since
the iron bacteria are of practical as well as scientific interest,
this monograph ought to be translated into English, in order
to attract wider attention among workers in hydraulic and
sanitary engineering, as well as in biological science. To the
six already-known species of iron bacteria, Molisch adds three
more, of which one grows in the stems and lea\es of aquatic
plants. He finds that these bacteria can grow quite well in
absence of iron, and that they can make use of manganese
instead of iron. The iron dissolved in the water is, according
to Molisch. merely deposited in the slimy sheaths of the
bacterial filaments in the form of carbonate of iron, which
becomes oxidised to ferric oxide, and this is apparently not
used by the bacteria in their vital processes but simply acts
as a protection to the protoplasm — in much the same way as
the silica deposits in diatoms and the epidermal cells of
grasses, and so on.

The iron bacteria occur in most bogs, chalybeate springs,
stagnant waters, and sometimes in iron water-pipes — in the
latter case often plugging up the pipes, besides fouling the
water itself; so far, no species have been found in sea- water.
These bacteria may be removed by filtration through sand or
coke, or by chemical treatment, and in either case Molisch
finds that the real cause of the disappearance of the bacteria
is the loss of soluble organic substances which are removed
by these processes, the absence of the iron itself being a
matter of indifference. Various other organisms — certain
.Algae. Flagellates, and Infusoria — are capable of fixing iron ;
some of these can also fix manganese, and their mode of action
appears to be the same as that of the iron bacteria. Molisch
also discusses the formation of bog iron, in which the iron
bacteria often play an important part : the formation of rust
in iron water-pipes, which is probably due primarily to the
action of the water itself acting on bare iron surfaces, though
here again the iron bacteria may flourish if organic substances
are present in addition to soluble iron oxide ; and the thera-
peutic use of chalybeate waters, which are often quite useless
for medicinal purposes on account of the precipitation of the
iron as insoluble ferric hydroxide.

105

106

KNOWLEDGE.

March. 1911.

NITROGENOUS SALTS IN SKAW.ATER.— Gebbing
{Iiitcniaf. Rcviic d.gcs. Hydrubiol. ittid Hydrogr., 19101 has
collected the results of the German South Polar Expedition with
reference to the^iitrogen-content of sea-water, comparing these
results with others previously obtained. Although chemical
in character, Gebbing's paper is of great interest in connection
with the distribution and periodicity of the plankton or surface-
living vegetation of the sea. The chief results are the
following. The content of the ocean in ammonium salts is
fairly constant, the average value being 0-05 milligrams per
litre. The distribution of the nitrates and nitrites is, however,
very variable, the highest proportion of these salts in the surface
water being found in the Antarctic Ocean, while it dwindles
towards the Equator from 0-5 milligrams to 0-1 milligrams
per litre. In the North Atlantic and in the North Sea there is
marked poverty in these salts, as compared with the Southern
Hemisphere, there being practically no increase on passing
northwards from the Equator. The scanty plankton of tropical
seas is probably due to the fact that the higher temperature
favours the growth of denitrifying bacteria, which attack
nitrates and nitrites, setting free nitrogen. At the Equator,
also, there is a much more rapid falling-off in nitrogen-content
in passing below the surface, and this may obviously be
attributed to the greater vertical circulation of the water in the
Tropics. Gebbing's interesting memoir is an important
contribution to biology as well as to chemistry and oceano-
graphy, and helps in clearing up various problems in the
distribution of the floating vegetable population of the sea.
which is largely used as food by the animal plankton as well as
by the larger denizens of the ocean,

CYCAD ROOT-TUBERCLES,— The remarkable coralloid
roots of Cycas have long been known to harbour colonies of
the Blue-green Alga Nostoc or Aiiahacna, which usually
form a definite layer in the cortex of these roots. In addition
to the Nostoc, bacteria occur in these roots, evidently causing
the formation of the tubercles and living in symbiosis with the
Alga. :\n interesting pap.:r on this symbiosis was read b\-
Professor Bottomley at the Sheffield Meeting of the British
Association (see Botany Notes in " Knowledge." October,
1910) ; the presence of the bacteria was noted by Schneider
in 1894 [Bot. Gaz.). Now, Zach iOesten: Hot. Zeitschr.,
19101 has found that in addition to the Nostoc and the
bacteria, these Cycad roots contain a fungus which attacks
the cortex cells and causes degeneration of the nuclei, loss of
starch and production of calcium oxalate in the infected cells.
No fungus filaments occur, however, in the Nostoc zone, and
Zach found that the fungus has nothing to do with the
causation of the tubers, but li\es in the roots simply as parasite,

RECENT WORK ON THE LOWER FUNGI.— Among
many interesting papers on the lower Fungi, there are some
which serve to link up the Yeasts to the more typical lower
.■\sconiycetes. The Yeasts have long been regarded as
degenerate Ascomycetes, their peculiar features — such as the
budding process of multiplication and the general absence of
sexual fusion — being correlated with their mode of life in
sugar solutions, which they decompose with the formation of
alcohol and carbon dioxide. The work of Hansen and others
has shown that not all Yeast species cause alcoholic fermenta-
tion, and that some species produce a definite, though simple,
mycelium or filamentous plant-body, while the spores of some
species have a peculiar hemispherical or hat-like form, which
agrees exactly with the shape of the spores in Eiidomyccs.
Barker's interesting discovery of the conjugating Y'easts, in
which the cells fuse in pairs before producing spores, may be
regarded as an indication of a simple sexual process similar
to that observed in such simple Ascomycetes as Erciiiascus
and Gymiioasciis.

Guilliermond {Rev. gen. Bot., 1909) has investigated
the following forms of lower Ascomycetes: — Eranascus.
Endomyces, Saccliaroiuycopsis. In Ereniasciis the cells
of the mycelium are at first multinucleate, but later become
uninucleate, and the asci arise in most cases from two fused
cells, but sometimes without fusion (parthenogenesis). In
fusion, a nucleus from each of the two cells migrates into tlu'

young ascus, the two nuclei fuse, and the fusion-nucleus
di% ides until the eight spore-nuclei are formed. In Eitdomyces
fibiiUger the mycelium, when in sugary liquids, forms buds
exactly like those of Yeast, and multiplies rapidly in this way.
In a paper which appeared simultaneously with that of
Guilliermond. Dombrowski [Coiiiptcs reiidits dii lab. dc
Carlsbcrg, 1909) showed that these Yeast-like cells of E.
fibnUgcr can produce conidia. differing from the sprouting
Yeast-like cells themselves in being able to resist heating to
55' C, a temperature which destroys the budding cells,
Guilliermond found that, as a rule, the asci arise singly as
branches from the ordinary mycelium, showing no trace of a
fertilisation process, and producing only four spores. In some
cases, however, anastomoses occur between the ascus
mother-cell and the neighbouring mycelium cell, or between
an ascus mother-cell and a Yeast-like cell, and this he thinks
points to degeneration of a former fertilisation. In Eiidviuyccs
mngnnsii the asci may either arise parthenogenetically, or
after conjugation of two mycelial branches differing in size,
four spores being formed ; in this species no Yeast-like budding
occurs, though resting cells are formed, InSaccharoinycopsIs,
there is no trace of fertilisation : the ascus contains four
spores; according to the culture conditions the plant
produces either a mycelium or Yeast-like cells, and the genus
is closely related to Eiidomyccs. being distinguished from
the Yeasts tSacchari)iuycctes) by the double wall of the
spore. Guilliermond concludes with a discussion of the
systematic arrangement and inter-relationships of the lower
Ascomycetes. pointing out that in Erciiiascus the only method
of reproduction is the formation of an ascus from two fused
cells, while in Eiidomyccs the asci may be formed either by
fertilisation or by parthenogenes. is and in addition to asco-
spores the plant reproduces itself by Yeast-like budding and by
conidia. The genus Eiidomyccs forms a transition from
Erciiiascus to the Yeasts, a form like E. fibuUgcr connecting
Ercinasciis to the ordinary Yeasts [Saccliaroiiiyces) and the
Conjug'ating Yeast (.^vgos(icc/;(7/'o/)/_vct's), while E. magtiiisii
leads to the Splitting Yeast iScliizosaccharomyccs).

Guillicrniond's important results are confirmed by a paper by
Lewis I Maine Agric. E.xp. Sta., Bulletin 178) on a new species
of Endomyccs discovered by him on decaying apples. In
this fungus — Endomyccs malt — the asci arise by partheno-
genesis on short lateral branches of the mycelium and produce
four spores, while conidia are also produced, but no Yeast-
like budding occurs and the Fungus cannot ferment sugar,
though Endomyccs magnusii can do this.

Westling (Svciisk bot. Tidskr., 1909) has described a new
genus. Byssochlamys, which he regards as forming a
connecting link between Endomyccs and Gymiioasciis. This
Fungus was found on plants that had been preserved in
alcohol, and it could not only exist but actually flourish in
strong alcohol (90%), which kills even the spores of most
other F~ungi ! This new Fungus proved even more long-
suffei'ing under adverse conditions than the ubiquitous and
highly-resistant Blue Mould {Peiiicilliiim ), and grew well at
37° C, ousting Pcnicilliiiin from a culture heated to this
temperature. Byssochlaiiiys reproduces itself by means of
ascospores. conidia, and thick-walled resting cells (chlamy-
dospores) ; the asci have eight spores and arise laterally from
a spirally coiled ascogonium, which is usually fertilised by a
male filament (antheridium) but is sometimes parthenogenetic.

HELIOTROPISM. — Some of the more recent work on
heliotropism was summarised in these columns a short time
ago. An interesting paper by Figdor {Ann. jard. bot.
Buitciizorg) shows that not only do foliage leaves perceive
the stimulus of one-sided light but that this stimulus is
transmitted backwards to the stem. Figdor experimented with
the leaves of Begonia, arranging his apparatus so that onl\-
the leaf-blade was exposed to the light, and found that not
onlv the leaf-stalk but the stem below the leaf showed strong
curvature towards the light. Figdor had previously shown,
also in experiments with Begonia, that the stem itself can
perceive and respond by curvature to the stimulus of light
falling upon it from one side, but his recent result is of
great importance in showing that in Dicotyledons, as well as in

March, 1911.

KNOWLEDGE.

107

Monocotyledons (e.g. grass seedlings), the stimulus can be
transmitted from the receptive surface of the leaf to the lower
parts of the plant.

MALE NUCLEI IX FLOWERING PLANTS.— Some
years ago, Nawaschin observed that when the pollen-tube of
an Angiosperm — he worked with Liliiiin niurtagaii and
Frifillaria tcncUa — reaches the embryo-sac, both of the
male or generative nuclei enter the sac, one fusing with the
egg and the other with the central nucleus (variously called
the "'secondary" or "definitive" or "fused polar" nucleus),
the embryo arising as the result of the former fusion,
and the endosperm as the result of the latter. This
remarkable discovery, which was made almost simultaneously
by Guignard. and has since then been confirmed in a
large number of Monocotyledons and Dicotyledons from
the lowest to the highest families, also led to the observation
that the male nuclei are elongated and worm-like, or even
spirally coiled, like the body of the motile male cells of lower
plants, and Nawaschin suggested that these nuclei might have
the power of independent locomotion. Most later writers have
rejected this view and considered that these nuclei are carried
along passively by streaming of the protoplasm in the embryo-
sac, but Nawaschin has recently (Oesterr. hot. Zcifsclir.,
1909; Ann. jard. hot. Buitcnzorg. 1910) obtained evidence,
almost amounting to positive proof, that the two sperms
actually move towards the two nuclei with which they fuse,
and that when spirally coiled like a cork-screw they rotate
during their passage through the embryo-sac, and thus burrow
through the protoplasm on their way to the egg and the polar
nuclei.

CHEMISTRY.

By C. .AiNSWORTH Mitchell. B..A. (O.xon.), F".I.C.

TEIRODON POISON.— Various species of Tctrodomn'
are common in the seas of Japan, and are extensively used as
food, after removal of the ovaries, in which is secreted the
characteristic poison of the fish. This toxic substance, which
is not present in the flesh, has been investigated by Mr. X.
Tahara iBioclieni. Zcits., 1910, xxx, 2551, who isolated it by
grinding up the ovaries of the fish with water, concentrating
the liquid, and precipitating albuminous substances and
phosphates. On now adding ammonia to the filtrate the
poison was precipitated in an impure condition, and was
subsequentlypurifiedby repeated treatment with lead acetate and
ammonia, and extraction with alcohol, in which it was partially
soluble. As thus purified tetrodon poison was a white powder,
which absorbed moisture on exposure to the air. It was nearly
insoluble in most organic solvents, and was only sparingly
soluble in water. Its reaction was neutral, and it is therefore
suggested that it should be termed tctrodoto.xine. instead of
tetrodonic acid, as heretofore. Apparently it was neither an
alkaloid nor a protein, but formed precipitates with the
hydroxides of heavy metals, and on treatment with dilute
hydrochloric acid was decomposed, with the formation of a
basic substance and a crystalline body containing no nitrogen.
The preliminary analyses indicated that tetrodotoxine had a
composition agreeing with the formula Ci.;HxiNOi,:. and this is
provisionally assigned to it. Physiological experiments proved
that the toxine was very active.

FILAMENTS FOR ELECTRIC LAMPS.— The modern
methods of preparing the filaments for incandescent electric
lamps are particularly ingenious, and illustrate the ways in
which chemical processes may be used to overcome apparently
insuperable difficulties. The carbon filaments are now almost
universally made by a method similar to that used in the
manufacture of artificial silk. A solution of nitrocellulose
(collodion cotton) in acetic acid is rapidly pressed through a
small opening, and the resulting filaments are twisted into the
required shape round carbon blocks, which are placed in
bo.xes of fire-proof clay and heated in a furnace until the
filaments are carbonized. They are then heated, by means of
an electric current, in an atmosphere of benzine, so as to
remove the last traces of volatile substances. It is essential
that the carbonised filament should be homogeneous through-

out, and that, as far as possible, it sho-ild have been converted
into the graphic form of carbon, which is not decomposed so
rapidly by the current, and thus reUrds blackening of the
glass.

The amount of electricity consumed i/ .■ carbon lamps has
led to the extensive use of lamps containing ;r;etallic filaments,
and an interesting survey of the diffeient processes that are
being used for the production of these is given by Mr. H.
Baumhauer in the Zeit. angcw. Cliem. (1910. xxiii., 2065).
The only metal of sufficiently high melting-point that has been
found suitable for the direct production of filaments from the
pure metal is tantalimi. and tantalum lamps have now been
sold for some years.

It was shown by Weiss [Zcit. aiiorg. Cheni., 1909, Ixv.,
288) that titanium and zirconium melted at too low temperatures
to be available for the purpose, while he was unable to melt
tungsten, the estimated melting-point of which is 2800°C.
Owing to this, it has not been found possible to prepare
filaments of tungsten directly from the metal, but the problem
has been solved in other ways. Thus, in one type of lamp no
longer on the market, tungsten filaments were prepared by
coating carbon filaments with a deposit of sublimed tungsten
chloride, and then heating them in a current of hydrogen to
reduce the tungsten compound to the metallic form, and expel
the carbon. Owing to the low resistance offered by the
filaments this process was abandoned, and at the present time
tungsten filaments are made by mixing tungsten oxide with an
excess of zinc dust and heating the mixture in a loosely-
covered iron vessel until the reaction takes place. The zinc is
then dissolved from the mass by means of hydrochloric acid,
and the reduced metallic tungsten is left in the form of a black
powder. This is made into a paste with caramel or gum
tragacanth, and is forced through minute openings, so as to
form filaments, which may be dried and heated in a current of
hydrogen to expel the carbonaceous agglutinating material.

.•\ still more recent method of manufacturing tungsten
filaments is by means of a colloidal solution of tungsten
obtained by alternately treating the metal with acid and
alkaline reagents, so as to obtain a flocculent gelatinous mass.
This is separated from water by squeezing it in silk, and is
then ready to be made into filaments without the necessity
of adding any binding substance. This process is used in the
manufacture of the "Sirius" and "Colloid" lamps, while in
the case of other tungsten lamps a binding material is also
employed.

Attempts to use other metals of high melting-point, such as
osmium and zirconium, have not proved nearly so successful
as the methods in which tungsten is used alone, and processes
of adding metals to the carbon filaments in the ordinary lamps
have also proved unsatisfactory. Thus, according to Mr.
Baumhauer, a lamp recently put upon the market contained
carbon filaments coated with zirconium, but although at first
there was greater emission of light and smaller consumption of
electricity, the life of the filament was considerably shortened,
and the consumption of electricity soon rose to that of an
ordinary carbon lamp.

GEOLOGY.

Bv Russell F. Gwinnell, B.Sc. A.R.C.S.. F.G.S.

THE ORIGIN AND PEOPLING OF THE DEEP SEA.

— Under this title a translation of a paper by Professor
Johannes Walther appears in the American Journal of
Science for January. Comparing land and water. Dr.
Walther points out that while temperature decreases with
height and depth respectively, in the ocean great depths,
and hence low temperatures, preponderate. Half the Earth's
surface is deep sea, with an average depth of four thousand
metres and a maximum of from eight to ten kilometres. The
inhabitants of this great area are considered with especial
reference to the light which they throw on the origin of the deep
sea. The characteristics of abyssal depths are: — (1) a uniformly
low temperature; (2) quiet water, with no noticeable movement;
(3) no light, and as a consequence no green-plant life. Hence
all light-hungry and plant-eating animals, and all which need
moving and warm water, are absent ; nevertheless, life is

103

KNOWLEDGE.

March, 1911.

abundant in the abysses. Where sunlight and green plants
are wanting no organic life can be maintained ; the fauna of
the deep sea is dependent upon the stream of cold south polar
water pouring oxygen and food into its abyssal depths. TIic
origin of this fauna nuisf. then, he sought in sunlit areas
rich in plants. When did the peophng of the abysses take
place ? The significant fact appears that no single Palaeozoic
animal is found in the present deep sea, although a number of
shallow-sea and other genera survi\e from the Palaeozoic Era
(e.g. Lingula, Mytilus, Pleurotomaria. Nautilus, Serpula, Astro-
pecten, the littoral Liinulus and the fluviatile Ceratodus,
besides soft-bodied animals which could not be preserved
fossil). Animals nowh\ ing below two thousand metres date only
from the Trias, the resemblance to Jurassic and Cretaceous
faunas being particularly close ; among the Echinoderms, for
example, are found Pentacrinus, Asterias, Echinus, etc.
Evidently, then, the peopling of the deep sea is traceable.
at the earliest, to the Triassic Period.

Now we know that the elevation of mountain-chains is
counterbalanced by the formation of extensive depressions ;
also that at no other period did such enormous mountain
folding occur as took place between Carboniferous and
Triassic times, when the Hercynian movements in Europe
occurred, the Appalachians were formed in America, the
Sudanese mountains were originated in Africa, and other
folding took place in Asia and elsewhere. /;; the deep ocean
abysses Dr. Walther sees the complementary depressions
to these mountain chains.

Thus general biological grounds, the stratigraphical position
of the present deep sea fauna, as well as tectonic investigation,
force us to the conclusion that the deep sea as a life-region is
not a characteristic of the Earth in its oldest periods, and
that its origin is found in the time when in all parts of the
present continents began tectonic folding movements which so
decidedly changed the relief of the Earth's surface.

THE GREAT NEW ZEALAND ERCPTION.— In the
January number of the Geographicitl Journal Professor
James Park describes the volcanic outburst of Mount Tarawera.
which took place in 1885. and which utterly destroyed the
celebrated pink and white terraces of Rotomahana. The
subsequent changes due to waning vulcanicity and to
denudation are also dealt with. Mount Tarawera — three
thousand six hundred feet high — rises abruptly from the lofty
rhyolitic plateau of Rotomahana. in the North Island of New
Zealand. During a space of about three hours the mountain
was gradually rent across from north to south by a great fissure,
nearly nine miles long, averaging two hundred \-ards wide and
from one hundred to three hundred yards deep. The \ulcanism
was of a. rare or new type; for whereas fissure eruptions are
distinguished by quiet emission of lava-floods, in this case the
ejecta were almost entirely fragmental, consisting of dust,
lapilli, bombs, and so on, derived from an augite-andesite
magma, intermixed with some rhyolitic ash. These materials
were spread over an area of nearly six thousand square miles,
in a sheet varying up to fifty feet in thickness, and dust fell on
vessels one hundred and fifty miles away. This great ash
sheet has since become covered with dense jungle, and has been
deeply scored by rain into narrow gutters and ridges. The
sections thus exposed are seen to consist of grey dust and
black ash, so well stratified as to be easily mistaken for a
subaqueous tuff.

During the course of the fissuring Lake Rotomahana was
encountered, and as a result a shattering explosion converted
the lake-bed into an active volcano o\er a mile in width. .A
native village on its shores was simply blown out of existence,
all the inhabitants being instantly killed. Several other
villages were overwhelmed with dust, not a soul surviving.
For a few months violent hydrothermal activity was displayed,
a pillar of steam rising to over fifteen thousand feet ; it then
waned and ceased, and the lake-bed filled up again with water.
About 1897, geysirs again began to play and the world-famed
Waimangu geysir was in action until two or three years ago.
Though this has now ceased, solfataric action is still very
conspicuous on the lake-shores. At Echo crater the forma-
tion of iron pyrites can now be seen in progress ; the crater-

floor is covered with a thin sihceous crust, through which
boiling water and steam escape. Interaction takes place
between the hot ascending mineralised waters, and the HoS
with which the steam is charged, and as a result FeSo is
deposited, first as a black and then a bright yellow film on all
the loose stones lying around.

Though of an abnormal type, the 1886 eruption was merely
one of a long succession of volcanic phenomena which have
been in progress since Pliocene times along the great tectonic
fracture known as the Whakatane fault — along which are
situated many other volcanoes, active, dormant and extinct.

GEOTECTONIC SYMMETRY.— Last November there
appeared in these columns a note dealing with the " Canadian
Shield." a great mass of gneiss and schist forming one of the
■' corner stones '" of the earth. In the American Journal of
Science for December R. Ruedeman points out the strikingly
symmetrical arrangement of the large area of Palaeozoic
rocks, which extends southwards from this Canadian
" protaxis," or shield of pre- Palaeozoic rocks. This area, the
'■ Palaeozoic Platform" of North America, is roughly bounded
on the west by a line connecting the head of Lake Superior
with the Ozarks, and on the east by a line enclosing the
.^dirondacks and Appalachians. It corresponds in its relation
to the Canadian shield with that of the Russian platform to
the Baltic shield. It is bounded on the west by the trans-
continental depression occupied by Cretaceous and Tertiary
rocks.

On either side of the Canadian shield there stand out,
like a corner-stone, a pre-Cambrian area (" Isle Wisconsin "
and " Isle Adirondack"), in quite symmetrical positions.
From each of these extensions there runs outward, along
the margin of the shield, a deep depression, the Lake
Superior basin and the St. Lawrence basin, respectively.
From these same corner-stones there extend southwards a
pair of arms, as it were, each consisting of a broad belt of
pre-Cambrian and early Palaeozoic rocks, nearly the full
length of the Continent. In both cases this elevated tract of
old rocks terminates to the south in a pre-Cambrian mass,
and these two masses — " Isle Ozark," on the west, and " Isle
Appalachia," on the east — are symmetrically situated.

Thus is enclosed a great median basin (that of the Great
Lakes and Ohio) which is itself symmetrically sub-divided by
the Cincinnati geanticline. This broad anticline, striking
north and south, separates two sub-basins of younger
Palaeozoic strata, situated in symmetrical east and west
positions : it dies away to the north, being replaced by the
Michigan basin. In this basin we may, perhaps, see a result
of a longitudinal oscillation of the axis of the Cincinnati
geanticline, for it also lies symmetrically to the whole arrange-
ment, constituting, with the Cincinnati uplift, the axis of
symmetry of the whole " Palaeozoic Platform."

One serious disturbance of symmetry has occurred, due to
Atlantic pressure exerted from the south-east ; this has
pushed the eastern arm inwards, thus giving rise to the
Appalachian basin-folds. Even here, however, the belt of old
rocks is recognizable, running south and south-west from New
York as far as Alabama.

MKTI-OROLOCA'.

By John A. Curtis. F.R.Met.Soc.

The weather of the week ended January 21st was, generally
speaking, dry but dull, with a good deal of fog. Temperature
was above the average in Scotland and in Ireland N., but
below it elsewhere. The highest readings were 53 at
Killarney and Scilly on the 16th, while the lowest readings
were 21' at Swarraton on the 15th, and at Durham on the
21st. In Scotland N. and the English Ch.annel. the lowest
readings were 35', but in all the other districts frost was
recorded, from 28° downwards. The lowest readings on the
grass were 15° at Crathes and Llangammarch Wells, and 16°
at Durham and Kew. Rainfall was deficient in all parts and
in most districts markedly so ; at many stations no rain was
reported during the week. In Scotland N., however, there
were stations where rain fell each day, though not to excess.

March, 1911.

KNOWLEDGE.

109

The amount of bright sunshine did not vary much from the
average except in Scotland E. and England N.E., where it was
nearly twice as much as usual. Crathes reported 27-1 hours
or 54 per cent. At Westminster the duration was only 0-2
hours for the week. The temperature of the sea-water
varied from 38' at Cromarty to 48^ at Plymouth and Seilby.

The weeli ended January 28th was warm,
and at each of the stations included in the
\Veel<ly \\'eather Report the mean was in
excess of the average. Maxima of 50' or
upwards were reported from all districts,
the highest being 59° at Killarney on the
25th. The lowest of the minima were
25° at Shields and 26' at Kilkenny and
Hereford. On the grass readings down
to 20' at Tunbridge Wells and 21" at
Dublin (Trinity College) were reported.
Rainfall was scanty in most districts, very
much so in some. In the Midlands the
total Idistrict) fall was only 0-04 inch, as
compared with an average of 0-50 inch.
.\t several stations the week was rainless.
In Scotland the fall was heavier, though
still below the average. Bright sunshine was
also below the average, except in Ireland S.
and England S.E. In Scotland E. the
deficiency was large, and in this district the
highest amount at any station was only
3-S hours (7%) at Nairn. The sunniest
station was Dublin, with 18-7 hours {32%).
.\t Westminster the amount was 5 • 3 hours
(9%). The sea temperature round our
coasts ranged from 36° at Cromarty, to 49' at Scilly.

The week ended February 4th contrasted strongly with
that which had preceded it, being
much colder and with much more
sunshine. Except in Scotland N.,
the temperature was below the average
in all districts, and in England S.E. the
mean value was only 34" -7, as com-
pared with 41" -4 in the previous week.
The highest reading reported during the
week was 51' at Colmonell, Killarney
and \'alencia. In the Midlands and
England N.W., the maxinmm did not
exceed 46 . The minima fell to 11" at
Balmoral and to 13" at Llangammarch
Wells, while the thermometer, exposed
on the grass registered as low as 1' at
Llangammarch and 6' at Birmingham.
Rainfall was scanty ; indeed over a
large part of the Kingdom the week
was rainless, but sunshine was abim-
dant for the time of year, and was in
excess of the average in all districts.
The highest amounts for the week
were 35-6 hours (57%) recorded at
Hastings, and 35-4 hours (55".) at
St. Heliers. Jersey. At Westminster
the total duration was 12-2 hours
(20%). The temperature of the sea-water
it may be added ranged from 36" at Eastbourne to 48' at Scilly.

The week ended February 11th was cool, cloudy and very
dry. Temperature was slightly above the average in Scotland
N., but below it in all other districts. The highest reading
was 53' at Killarney on the 11th, but as a rule the ma.xima
were below 50' ; in England N.E. and E. the highest was only
45'. The lowest reading was 11' at Balmoral, also on the
11th. At quite a number of stations the maximum and the
minimum were both recorded on the same day. The lowest
reading recorded on the grass was 8' at Balmoral. Rainfall
was below the average e\er\'where. and in the English Channel
less than one-twentieth of the normal amount was reported.
Even in Scotland N. the total collected was only one-sixth
of the average. Sunshine was deficient generally, though in
Scotland N. and in Ireland it was slightly in excess. Valencia,

Figure 1.
A single Rotifer, feeding.

in Co. Kerry, reported the largest amount, 21-0 hours (33%)
and Deerness, in Orkney, had the next highest amount with
18-6 hours (32%). Westminster reported 5 ■ 9 hours (9%). The
sea temperature varied from 36" at Cromarty to 47' at Scilly.

INVESTIGATION OF THE UPPER AIR.— On January
17th, a balloon from Pyrton Hill reached
,in altitude of fifteen thousand metres, at
which height the temperature registered was
J 10° absolute scale. At thirteen thousand
metres, however, the temperature v.as only
202' absolute, or— 96' F., which is the
lowest temperature recorded in the British
Isles up to the present time.

The record of a kite ascent at Pyrton
Hill, on January 26th, showed a sharp
inversion of temperature at a height of nine
hundred metres, and while at five hundred
metres the humidity was 100 per cent.
I saturation), at a thousand metres it was
only 30 per cent. The cloud level was not
reached on this day at a thousand metres.

MICROSCOPY.

By A. W. Shepp.\rd, F.R.M.S.,

K-itli tin' assistance of the following
niicroscopists : —

Akihlr C. Bankield : jAMts Bl rton ; The Rev.
E. \V. BowELL, M.A. ; Charles H. Caffyn ; .\rthur
Earland, F.R. M.S. ; Richard T. Lewis, F.R.M.S. ;
Chas. F. Rousselet, F.R.M.S.; D. J. Scoureield,
F.Z.S., F.R.M.S. ; C. D. Soar, F.R.M.S.

RED -SNOW. — Red-Snow, Gory-Dew, Bloody-Rain, and
such-like names show that phenomena of this class appeal to
the popular imagination. When some
rapidly-increasing organism suddenly
produces a blood-red pool on the
ground, the simple-minded observer
ma\' readily suppose that it has come
down as rain, and in superstitious
countries and times there is fine scope
for connecting the appearance with
tragic or momentous events, the ven-
geance of heaven, and what not.

Even the scientific naturalist feels

his imagination excited as he reads of

'Crimson Cliffs"

commonly credited
of red-snow, in the

Figure 2.
luster of Antarctic Red Rotifers.
(Pliilodina grcgariaJ

Sir John Ross's
extending for miles.
De Saussure is
with the discovery

course of his pioneer journeyings among
the .Alps, in the eighteenth century, but
according to Schmarda (1845) the
phenomenon was known to the ancients,
and is mentioned by Aristotle (Hist.
.Animal, v., 12). In the nineteenth
century there were numerous records
of red-snow, and there is now quite an
extensive literature of the subject. Ross
appears to have been the first to find
red-snow in the Polar regions, and he
brought samples of it from the Crimson Chffs of Greenland.
De Candolle (1824) compared the .Arctic and Alpine red-
snows, and declared them to be identical.

Red-snow has been found all over the world in suitable
localities, but it does not appear to be of general occurrence
in snowy regions. Darwin saw it in the Cordillera, but
Hooker never saw it, either on his Antarctic voyage or in the
Himalayas. Friends whom I have asked about it saw
none on the snowy mountains of Norway and Switzerland.
According to some accounts it appears to be most plentiful in
the North Polar region, where it is reported from Spitsbergen.
Scandinavia, Siberia, and so on. It is recorded also for the
.Alps. Pyrenees, Carpathians and Ural Mountains, the Sierra
Nevada in CaUfornia, Chili and Ecuador, in South America,
and so on.

110

KNOWLEDGE.

March, 1911.

In the .\nlarctic, red-snow appears to be less coniinon than
in the North Polar region. The Shackleton Expedition did
not find any for certain, but some members saw snow dis-
coloured with what they supposed to be a red Rotifer common
there. Bruce's E.\pedition found a little of it, but the only
record I know is in Charcot's preliminary report of his last
Expedition (1910). The naturalist of that expedition, M.
Gain, informs me in a letter that they found both red and
green snow, the former in considerable quantity, the latter
forming extensive meadows (" prairies ").

What is red-snow ? As to the colour of it, is it so very
bright ? Perhaps we who have not seen it expect too much !
Some describe it as blood-red or crimson ; others say it is a
dull purple: Darwin noticed the footprints of his mules stained
a pale red, and the snow was only coloured where it had
thawed rapidly or had been crushed. Sir Philip Brocklehurst,
who saw our only supposed red-snow, tells me it was a very
dingy yellow.

Red-snow has been almost universally attributed to a
supposed Alga, best known as Protococciis nivalis, though
it has borne many names, and is now officially recognized as
Spliacrclla nii'alis. It is described as consisting of spherical
cells, about a one-thousandth part of an inch in diameter,
with a thickish cell-wall, and the protoplasmic contents

Figure 3.

Spliacrclli! iiii'dlis. two clusters and two free swimming

cells, the latter are marl;rd 4.

permeated with chlorophyll, which is, however, completely
masked by the red pigment haematochrome. In the growing
season the cells enlarge and divide, usually into four daughter-
cells, which then separate, take an oval form, and swim about
by means of two fiagella, which are extensions of the proto-
plasm projected through the envelope.

It has been so little suspected that any organism but
Protococcus nivalis could produce red-snow, that one may
suppose it has sometimes been recorded as that species,
without careful examination. Such was the view of Vogt,
who accompanied Agassiz on his Alpine journeys.

Shuttleworth, in 1839, first suggested that other species
might participate in making the red-snow.

Vogt (1840) made the remarkable discovery that his samples
of red-snow contained a Bdelloid rotifer in abundance. He
found associated with the rotifer some smooth and some
warted globules, which he satisfied himself were its eggs, and
he rather hurriedly concludes that there is probably no
Protococcus nivalis in existence, the name having been
given to rotifer eggs ! Those globules of Vogt's are unlike
any known eggs of Bdellnids. and I am sure he was wrong
about them.

Vogt is not the only authority for the pi-eseuce of rotifers in
red-snow. Lagerheim, in 1892, found a Bdelloid in red-snow
in Ecuador. He identified it as related to Pliilodina roseola,
which is the same species as Vogt supposed his animal to be.

Now, although the Shackleton Expedition found no indubit-
able red-snow, we found abundance of red rotifers, which
increased with prodigious rapidity and formed conspicuous
blood-red stains on stones at the margins of lakes. I named it
Philodina grcgaria.

Vogt gives a very good figure of his supposed Pliilnduia
roseola, and the spurs are of such a form that Ehrenberg
doubted the identification. These spurs are very similar
to those of P. grcgaria. The similar habitat gives colour
to the suggestion that they are identical. The ."Mpine rotifer,
living on the surface of snow, must become active at just

about the melting-point temperature. — /-".^^rc'^'ifr/if lives frozen
in ice for years, and resumes activity whenever the ice melts.

It is now admitted that, while Sphaerclla nivalis may be
the connnonest cause of red-snow% animals of various kinds
may take part in producing the phenomenon. M. Gain, of the
Charcot Expedition, makes the latest addition to the list, as he
tells me he found reddish mites fairly plentiful in the Antarctic
red-snow. There is probably a considerable fauna of red-snow.

What is the significance of the red colour of so many
animals which li\'e on the surface of snow ? Has it a
physiological function in relation to light, enabling the animal
to absorb the rays, w-hich will just make life possible in that
inhospitable situation ? It is noticeable that the red colour
of the rotifers, both .Alpine and Polar, is confined to the
stomach.

There is a tendency, even in science, to reason from
insufficient data to erroneous conclusions — "jumping to a
conclusion," as it is termed in unscientific language. Let us
take warning from some of the facts connected with red-snow.
Vogt affords us an example of the danger, in his observations on
the supposed eggs of the rotifer of red-snow. He watched
till he observed a rotifer " deposit " one of the globules. If
this were sufficient evidence, we could soon find such
marvellous instances of alternation of generations as would
rival the fabled origin of the Barnacle Goose. Had Vogt
begun at the other end and waited for an egg to hatch, he
would, perhaps, have reached another conclusion.

Red organisms are common enough apart from red-snow,
and there is no need to assume that all the red organisms
found in that situation have their red colour in virtue of the
association. Vogt includes among his animals of the red-
snow a Water- Bear with two claws, which he refers to as
Arctiscon and Macrobiotns, but the number of claws and
the red colour make it pretty certain that it was a larval
Echiniscns. Ehrenberg got several kinds of Echiniscns
high up (11,138 feet) on Monte Rosa. It seems a reasonable
supposition that the colour of these animals has a special
relation to a life among snow, but so far from this being the
case, it is the normal colour in this extensive genus, in
species living in all sorts of situations. One of the brightest
red species inhabits .Australia, where red-snow is little likely
to occur.

Ehrenberg found on Monte Rosa, along with ihu Echi)iisci,
a bright red rotifer, which he named Callidina scarlatina.
It was found dried up, like pink dust, and, I believe, scattered
over the snow. But Callidina scarlatina is not specially
addicted to a life on the snow or even on mountain-tops. If
Mr. Bryce's identification is right, it is a familiar species among
hepatics growing on trees, in shady glens and similar places.

As to Sphaerclla nivalis itself, the Alga of red-snow, I
find upon enquiry that it is a flagellate Infusorian, related to
that very energetic plant-animal, the Globe-animalcule. Volvo.x.
claimed alike by zoologists and botanists. If the flagellates
are conceded to zoology, then all the organisms of the red-
snow are animals. , ,.,m,,, .. r-ucr- -c-vc
James Murray, F.R.S.E., F.Z.S.

MICRO-SLIDES ILLUSTRATING MITOSIS.— Every

student of Cytology appreciates the difficulties attending the
preparation of slides illustrating the phenomena of nuclear
division. We have received from Mr. C. Baker, 244, High
Holborn, a sample slide showing mitosis in all phases, as
exhibited in the growing point of the root of Liliuni. His list
of slides also includes the root-tip of hyacinth and onion,
and the testes of the newt showing the developing spermatozoa.
We have received a selection of slides from Mr. H.
(iunnery, Acomb, York. He has specially devoted himself to
the preparation of slides illustrating the phases of development
in the embryo-sac and pollen mother-cells of Liliuni spp.
The slides we have examined are very good indeed. Special
mention may be made of one, showing the embryo-sac
containing two daughter-nuclei resulting from the first division
of the nucleus of the megaspore. Mr. Gunnery has also sent
for examination sets of botanical .slides, designed to meet the
requirements of the Intermediate Science and Board of
I-Mucation Examinations. All the types are well illustrated in
these sets, which are very reasonable in price.

March. 1911.

KNOWLEDGE.

Ill

E. LEIT/ (LONDON) .A. N I) K. WINKEL
IGOTTINGEN).— We have received from E. Leitz
(London), Catalogues Nos. 7 and 8, devoted to photomicro-
graphic apparatus, and projection apparatus and drawing
appliances involving the principle of projection. These
catalogues give details of new apparatus specially designed to
meet the most recent requirements. In this connection
attention may be drawn to the photomicrographic apparatus
as suggested by Professor Hermann for taking photographs
of insects. .A.s an appendi.x to the list No. 7 there are two
plates of reproductions of actual photographs taken with the
objectives and apparatus of E. Leitz.

Messrs. H. F. Angus & Co.. 83, Wigmore Street, W., have sent
us their new list of microscopes and accessory apparatus, by
K. W'inkel. Gcittingen, for whom they are acting as agents in
the L'nited Kingdom. The optical instruments of this firm
deserve to become better known amongst English workers,
and we can cordially recommend the intending purchaser of
a microscope to consider this list before coming to a decision.
The apparatus listed ranges from the simplest demonstration
instrument to that suited for the most exacting research.

KOV.AL MICROSCOPICAL SOCIETY. January ISth.
1911. — Professor J. Arthur Thomson, F.R.S.E., President,
in the chair. — Mr. T. Chalkley Palmer made some remarks
upon a slide of Sitrirclla clegaiis, stained to show the
protoplasm which extended in unbroken continuity throughout
the tubes of the keels, where, by its streaming, it acted
through minute clefts upon the surroundings and moved the
diatom to and fro. The special point was that the mount
showed R. Lauterborn to be mistaken in assuming that
the streaming substance in the keels was gallerte or jelly. —
Professor J. Arthur Thomson, the retiring President, took as
the subject of his address " The Determination of Sex."
He discussed, historicallj- and critically, five theories or sets
of suggestions.

(1) It has been suggested that environmental conditions
operating on the sexually-undetermined, developing offspring-
organism, may, at least, share in determining the sex. The
evidence in support of this has in great part crumbled before
criticism, and before the counter-evidence of cytologists and
Mendelians. But when we think of the gamut of life, we feel
it to be rash to exclude even this possibility.

(2) It has been suggested that the sex is quite unpredestined
in the germ-cells before fertilisation, and that it is then settled
by the relative condition of the gametes (as affected by age,
vigtiur, and so on), or by a balancing of the inherited tendencies
which these gametes bear, neither ovum nor spermatozoon
being necessarily decisive. The evidence in support of this is
very far from satisfactory. Yet in view of some sets of experi-
ments, of R. Hertw-ig, in particular it seems rash to foreclose
the question.

(3) It has been suggested that the sex is predestined at a
very early stage by the constitution of the germ-cells as such,
there being female-producing and male-producing germ-cells,
predetermined from the begimiing and arising independently
of environmental influence. The evidence in support of this is
\ery strong, both on experimental and on cytological grounds.

(4) It has been suggested that maleness and femaleness are
Mendelian characters, and one form of this very attractive
theory is that femaleness is dominant over maleness, and that
females are heterozygous as regards sex, and males homo-
zygous as regards sex. But there are grave difficulties as well
as very striking corroborations.

(5) It has been suggested that environmental and functional
influences, operating through the parent, (or, in short, the
parent's acquired peculiarities), may alter the proportion of
effective female-producing and male-producing germ-cells.
See, for instance, Russo's experiments on rabbits. This
possibility remains tenable.

(6) It is suggested that there is no sex-determinant at all in
the usual sense, but that what determines the sex of the off-
spring is a metabolism-rhythm, a relation between anabolism
and katabolism. or a relation between the nucleoplasm and the
cytoplasm. Many sets of facts converge in the inference that
each sex-cell or gamete has a complete equipment of both

mascuhue and feminine characters — of which there are doubt-
less chromosomic determinants. It may be that the liberating
stimulus which calls the masculine or the feminine set into
expression or development is afforded by the metabolism-
rhythm set up in the cytoplasmic field of operations. It may
be that this metabolism-relation — between nucleoplasm and
cytoplasm, doubtless, and likewise between anabolism and
katabolism — leads first and necessarily to tlie establishment
of ovaries or of spermaries, and secondly, either directly, or
through the gonads with their internal secretions, to the
expression of the contrasted masculine or feminine characters.

(71 This interesting problem still implies a study of un-
certainties. But some progress has been made in the last
quarter of a century, and especially of late. Three general
impressions stand out clearly: (1) That the main steps of
progress have rewarded the cooperation of several distinct
methods; (2) That the variety of organisms is so great that
we should be very slow to argue dogmatically that what holds
good in one set must hold good all round; and (3) That what
is especially necessary on the part of biologists (according to
their opportunities) is a thatigc Skcpsis, — until we arrive at
secure conclusions.

This being the .Annual Meeting of the Society, the following
Fellows were elected as Officers and Council for the ensuing
year : —

President, H. G. Plimmer, F.R.S. — Vice-presidents. A. N.
Disney, R. G. Hebb, E. Heron-.AUen, J. Arthur Thomson. —
Treasurer, Wynne E. Baxter. — Secretaries, J. W. H. Eyre,
F. Shillington Scales. — Members of the Council, F. W. W.
Baker. J. E. Barnard. F. J. Cheshire. C. L. Curties, C. F.
Hill, J. Hopkinson. P. E. Radley, J. Rheinberg, C. F.
Ronsselet. D. J. Scourfield, E. J. Spitta, Sir .Almroth E.
Wright. — Librai'ian. P. E. Radley. — Curator of Instruments,
C. F. Rousselet. — Curator of Slides, F. Shillington Scales.

ALGA FROM THE SEYCHELLES ISLANDS.— A friend
at the Quekett Microscopical Club recently gave me some
specimens of an Alga from the Seychelles. Definite informa-
tion was not procurable as to its e.xact habitat, but it was
believed to be marine and to occur on rocks on the sea shore.
Examination under the microscope leaves little doubt that it
should be classed with the Lyngbyeae. It does not appear to
correspond exactly with a recorded British species and
certainly not with any from fresh water. It consists of
unbranched filaments of considerable length ; these are

A...

composed of a somewhat thick-walled and strong sheath-like
tube, inside which are discs of protoplasm, normally packed
closely together ; they are without individual cell walls and
are. in the specimens given to me (preserved in formalin), of a
pale olive green, and are somewhat granular in appearance.
Figure 4, A. In what seems to be the young but mature
condition these fill the tube, but later they show a tendency
to cling together in rouleaux of six or more. Probably these
are " hormogones," the non-sexual reproductive bodies of
*he order. They would emerge from the tube, and being
disseminated in the water, develop into new filaments. The
discs are lenticular, somewhat thicker in the centre than
towards the periphery (Figure B, face view). When packed

112

KNOWLEDGE.

March, 1911.

closely together in the sheath this is not evident owing to their

compression, but when relie\ed from the pressure, and a few

only adhering together, they form short cylinders, with

rounded ends or almost circular collections (Figures C, D).

In the older specimens the wall of the filament is greatly

thickened and shows a distinct lamellose structure, the outer

layers frequently split off, and where injured by sharp bending

become broken, ragged and almost fibrous in character. In

these cases the protoplasm is reduced in amount, loses its

bright colour, becoming brownish, and mostly collects into the

masses already described, as at D. The plant differs from the

more common species of British Lyngbyeae in two respects.

It is much larger than the majority; at E is represented

on the same scale Lyngbya iniiiitiaia Kutz, a rather

small but plentiful species ; the filaments in this case are 4m

in diameter ; while those from the Seychelles are from

30 to 35m, without the sheath. Dr. Cooke gives 25-30m

without sheath for L. acstuarii, a large British species

found in brackish and salt water, but 7-10m is the average

diameter of the greater number. Also the protoplasmic discs

are very much thinner than is usual in our own familiar

species ; here they average only about 2m at the edge, and

sometimes in young specimens less, looking under moderate

magnification like discs of paper filling the thick walled tube.

The literature available on these lowly members of the

\egetable kingdom is very scanty, and scattered through

pamphlets and proceedings of various societies. If any reader

of " Knowledge " can add information to what I have

supplied, it would, no doubt, be welcome to many interested

in the studv of the lower .^Igae.

J. b.

yUEKETT MICROSCOPICAL CLUB.— January _:4th.
1911, Professor E. A. Minchin, M.A., President, in the chair.
Through the courtesy of Mr. E. M. Nelson, a note on the
" Amician test " (see " Knowledge," 1910, page 325), by Mr.
F. J. Keeley, of Philadelphia, was read. Mr. Keeley possesses
a balsam-mounted slide, labelled "XaviciiUi Atnicii, Florence,
Italy. P'rom Professor Ainici to C. .V. Spencer." It is a
fresh-water gathering and contains, besides a large proportion
of typical A', rlioinboidcs, a few \'al\es under 50m in length
which form a class by themselves on account of their extreme
delicacy and transparency. 1 he author gives measurements
of twenty valves and the number of transverse striae
per -01 millimetre in five typical specimens. From these
particulars, Mr. Nelson considers the identitv- of the .Amician
test with the "English A', rlioinboidcs" finall\- determined. —
Mr. C. F. Rousselet, F.R. M.S., described and exhibited prepara-
tions and drawings of three new species of Rotifera. These
are Anuracopsis navicida, BracJiionus sataniciis and
Brachionus havanaensis. These will be fully described and
figured in the next issue of the Club's Journal. — Mr. R. T.
Lewis, F'.R.M.S., read a paper " On the larvae of Mantispa."
He referred to the great apparent similarity between mature
specimens of the Mantidae family and those of the
sub-family Mantispidae. The wing structure, however,
places the Mantis family amongst the Orthoptera and
the Mantispidae with Neuroptera. The Mantidae construct
a curious capsule or ootheca in which the eggs are
laid in symmetrical rows and are entirely covered in from
\iew, while the eggs of Mantispa are laid singly, each mounted
on a slender stalk. On first emerging from the egg the young
Mantis closely resembles the adult except as to size, colour,
and the absence of wings. In Mantispa, the larva on emerging
bears not the slightest resemblance to the perfect insect (a full
description with drawings and exhibition of specimens was
given). On leaving the egg the larva bores its way into
the ovisac of a spider and feeds upon the eggs, or young,
until it has changed its skin a second time. The legs then
disappear, the head is reduced in size and loses its antennae,
and the larva becomes a helpless fleshy grub, which presently
spins a cocoon. Emerging from this it passes through two
more moults and becomes a full-grown neuropterous
Mantispa.

Mr. H. Ciunnerx-, of .Acomb, York, sent for exhibition a
number of preparations, chiefly botanical, some especially fine
of nuclear di\ision in Lilinm. These were shown under a

number of microscopes kindly lent by Mr. C. Baker. Mr.
Gunnery also sent a mimber of lantern slides, mostly photo-
micrographs. These were projected on to the screen. The
thanks of the meeting were accorded to Mr. Gunnery and to
Mr. Baker.

ORNITHOLOGY.

By Hl-gh Bovm Watt, M.B.CJ.C.

SPEED OF FLIGHT OF BIRDS ON MIGRATION.—
Giitke in his well-known work on " Heligoland as an
C)rnithological Observatory" (1895). has a chapter on the
velocity of flight of passing birds, in which some estimates of
so high a value were given as to cause not a little surprise.
The speed of Hooded Crows was stated to be one hundred
and eight geographical miles per hour, and that of the Northern
Bluethroat as one hundred and eighty: and Plovers, Curlews,
and Godwits, were noted in numbers as crossing the island,
over a measured distance, at a rate of nearly four miles in one
minute.

A series of observations made in the autunm of 1909, under
the direction of Dr. J. Thienemann, at the Migration Observa-
tory at Rossittcn (East Prussia), give very different results
from Gatke. At Rossitten allowances were made for the
factors influencing the birds (such as wind), and the following
figures arc the average results for the species named, calculated
to English miles. (See British Birds, January, 1911,
page 260.) They are here placed in order, from the lowest
speed upwards : —

Sparrow- Hav.'k ... 25t miles Brambling ... 52i miles

Lesser Black- Siskin ... ... 34 ij- „

backed Gull ... 31 ,, Linnet ... ... 34 J ,,

Great Black-liacked Peregrine Falcon... 37

Gnll 3U .. Crossbill 37?, ,.

Hooded Crow ... 31f „ Jackdaw 38J

Rook iZi „ Starling 46;\ „

Chaffinch iZ'i „

There are curious contrasts in these figures, and it seems
clear that no fixed conclusions can be drawn until many
further observations have been made and coordinated.

UNTOWARD FATE OF AN EGG OF THE GREAT
AL'K [.Ale a iinpcnnis). — Mr. E. Bidwell, in the current
number of the Ibis (January 1911, page 184), tells a curious
story of disregard of an ornithological treasure in the form of
an egg of this extinct species. For about twenty years Mr.
Bidwell has known of the existence of an egg in a small
museum at Dinan, France. In September last, along with
Mr. Henry Stevens, he visited the place with the intention of
photographing the egg. The Castle (lately a prison) was
found to have been made into a museum, but not many
natural history specimens were exhibited, and the curator
knew nothing of any Great Auk's egg being in the collection.
The birds and other animals had been considered not worth
moving, and on the pre\'ious afternoon had all been stored in
an attic, at the Hotel de Ville. There, on the floor, amidst a
jumble of stuff'ed birds, the remains of the Great Auk's egg
were found. Mr. Stevens photographed the two largest
fragments, and his photographs were shown by Mr. Bidwell,
at a recent meeting of the British Ornithologists' Club. The
price of a good specimen of this egg at present is about £250.

THE CENTRAL NEW GUINEA ORNITHOLOGICAL
EXPEDITION.— The British Ornithologists' Union expedition
has suffered a further loss by the compulsory retiral. through
ill-health, of Mr. Walter Goodfellow, from the leadership.
Capt. C. G. Rawling, surveyor to the party, has been
appointed to take command. The arduous character of the
undertaking rec"i\-es further emphasis from the last report
published (Ibis, January 1911, page 186). The camp and
surrounding country had been completely flooded by the River
Mimeka, and when the floods subsided the whole camp became
a bog. Headquarters were then remo\ed to the Waitakwa
River for a further advance.

IRISH BIRDS— NEW RACES OR FORMS.— Visitors to
the Natural History Museum, South Kensington, at present.

March. 1911.

KNOWLEDGE.

113

will see amongst the British Birds, specimens of Coal-Tits
with freshly-written labels bearing the name Irish Coal-Tit
[Pants liihcrnicns). Mr. W. R. Ogilvie-Grant has recently
described this bird as a new species and thns named it
(Bulletin British Ornithologists' Clith, Vol. XXVII, pages
36 and 37), on the strength of certain differences from the
British Coal-Tit. It wonld seem, however, that the new form
has yet to make good its claim to specific rank, sound critics
being inclined to regard it rather as a geographical form.

This makes the third Irish bird which has recently been
described and named as distinct from recognised species. The
other two are the Irish Dipper named Cinclns ciiicliis
hibernicHs. by Dr. Ernest Hartert, and the Irish Jay named
Garriiliis glaiulariiis hihcniiciis. hv the same writer and
Mr. H. F. Witherby.

HOW MAW KINDS OF BRITISH BIRDS ARE

THERE? — The latest anthorhative "List of British Birds"

is by Mr. W. R. Ogilvie-Grant (1910) and ennmerates four

hundred and forty-two species. An analysis of the grouping

adopted by the writer (which is the same as that used in

the Natural History Museum, South Kensington), gives the

lollowing instructive figures : —

133 species are resident and breed. ) in-u j-
- -, • , . . =183 breedmg

32 species are regular summer visi- I- . "

tors, and breed I

55 species are regular autumn, winter or spring

\isitors ; not breeding.

9 species are occasional visitors ; used to breed.

192 species are occasional visitors; never known to

breed. To this number the American Pipit,

mentioned in the last number of " Knowledge "

(page 76) falls to be added.

1 species is e.xtinct (Cireat Ank).

Total 442 species admitted nnciucstionably.

3 varieties are named in the List, but not numbered.
35 species, of which thehistorj'is doubtful, are named

in the List within brackets, and are not numbered.

4S0 birds in all are thus found named in this List.

In the scientific names throughout this List, binomials
only are used, the author having, with sound judgment, not
adopted the new trinomials which are being used now by
various writers.

NOTES FOR CORRESPOXDKXTS.— D.N. H.,Chesham.
— Owls are not uncommon at Hampstead, and recently I
have heard two kinds calling. On 1st May, 1910, I saw a
"Brown" Owl (probably Syrniu}!! aliico), seated high up in
an ash tree in Piatt's Lane, mobbed by two noisy Mistle-
thrushes and a Blackbird, which it treated with unmoved
contempt. The Barn-Owl (Strix fianuiica) is known to nest
each season, and the Long-eared Owl {Asis otns) has nested
in Ken Wood.

The M.ARSH-TiT [Pants paliistris. or, if a trinomial is
used, P. p. drcsscri) is not rare in Bucks, and nests, but it
may be local in its distribution, as it is in other districts. If
the bird you saw was feeding it may have been taking small
molluscs, as it is almost omnivorous.

Two forms of " Marsh " Tit are now recognised in this
country. The new one is named the British Willow-Tit
[Parus klcinschiiiiilti or P. atricapillns klcinschniidti'i.
and has been recorded from so many places that a careful
examination of all " Marsh " Tits met with should be made by
observers. For description, see Witherby's " British Birds,"
Vol, I., pages 23, 44, and 214 (1907), and'Vol. IV., pages 146
and 284 (1910-11).

PHOTOGRAPHY.

By C. E. Kenneth Mees. D.Sc.

STANDARD LIGHT SOURCES.— Inasmuch as photo-
graphic investigations are mainly concerned with the
measurement of the effects of light, it is naturally of great
importance that a standard source of light of known strength
and constancy should be readily available. Unfortunately,

neither the production nor the measurement of light are
susceptible of the very accurate control possible to other
sources of energy, the accuracy of measurement being limited
by the difl'erence in intensity which can just be perceived bv
the eye when two adjacent patches are illuminated ; while the
production of a standard light depends at present on a set
of definitions of a standard lamp, which has resulted in the
introduction of a large number of different standards more
or less harmonized by photometric comparisons.

There is, indeed, no international standard of light in the
sense in which the " volt " and " ampere " form electrical
standards : although the British standard which is know-n as
the '" candle," and in practice is the light of a Pentane lamp,
which has been adopted by most countries, the chief exceptions
being Germany and Austria, of which the standard is the
" hefner," the light of an Amyl-acetate lamp, of which the
intensity is nine-tenths that of the standard candle.

Attempts have been made to introduce as international
standards the light given by platinum at its melting-point,
or by platinum foil heated by a standard current. But the
practical difficulties attending the use of these methods seem
to have prevented their general employment.

F"or photographic purposes, what is required is an accurate
secondary standard, but the difficulties here are even greater
than in visual work because lamps of different kinds and of the
same visual intensity, do not produce at all the same effect
upon a photographic plate, owing to differences in the spectral
quality of the light produced.

The light by which photographic plates are generally used
is da\light, and this differs so greatly in composition from
artificial light sources that comparisons of plates made by
artificial light sources maybe most misleading when the plates
are used bv daylight, especially in the case of orthochromatic
or panchromatic plates. This difficulty may be overcome by
special methods of screening the light, and wdiat is required
for photographic investigation is, therefore, a method of
producing light sources of constant intensity, which can be
referred to some priinary standard. The intensity of these
light sources should be between one and four candles and
they should be capable of burning for at least fifteen minutes
without attention and without a variation greater than one
per cent.

When the subject was discussed at the last International
Congress of Photography the general opinion of the speakers
seemed to be that the choice for such a secondary standard
lay between acetylene burners and small metal filament
electric lamps : the former being largely used in France and
England, while in Germany the electrical standard is more
favoured. An acetylene burner giving a single cylindrical jet
of flame, from which a small portion is selected by means of a
hood having a horizontal slit, will easily give an accuracy of
one per cent, and has many advantages ; notably, that it will
burn for a long time without any attention, pro\ ided that the
pressure in the generator is constant. The chief disadvantage
of acetylene standards is that for accuracy they require very
large generators and they are consequently rather expensive to
instal, while it is impossible to render them portable.

-An examination of small four-volt metallic filament lamps
has shown that they will be constant to one per cent, if the
voltage is maintained constant to a one-hundredth of a volt
which can be done with comparative ease by means of a
potentiometer, and as different lamps can be arranged with
scries resistances to give the same candle pow-er for the same
impressed electro-motive force, it should be possible to
prepare an electric secondary standard without great difficult)'.

The chief objections to these small lamps as standards — the
rapidity with which they age — is of little importance in photo-
graphic work, where the total duration of exposures in a day's
work wonld be exceedingly small.

It may be remarked that there seems to be an increasing
tendency to use small metallic filament lamps, run oft" accumu-
lators, as standards, especially in simple photometers of the
portable tj'pe, and that in many cases these lamps are simply
assumed to be constant without any control whatever. They
are, in fact, very far from constant, not only gi\ing a different
intensity after the accunn:lator is charged, or when it is nearly

lU

KNOWLEDGE.

March. 1911.

exhausted, but decreasiug rapidly from the time when the
accumulator is switched on for live or ten minutes. Lamps
used in this way may easily give rise to errors of ten per cent,
or more, an amount which cannot often be considered
negligible. The question as to the " primary " standard to
be adopted for photographic purposes is still quite undecided,
and is, probably, the most important problem to be considered
by the next International Congress of Ph<itography.

THE THEORY OE THE IRIS DIAFHR.^GM.— Mr.
C. E. Lan-Da\is recently read before the Optical Society a
paper in which he worked out the geometrical theory of the
iris diaphragm, showing the conditions which will produce
the maximum aperture, both for complete closing and for
closing to a known aperture. The aims in designing an iris
diaphragm are to obtain : —

The greatest apei'ture consistent with the smallest opening,

A long scale with equal division,

Light weight.

Ease in working,

Ereedom from faihue, and

Reasonable cost.
The factors which can be varied are the position of the
pin in the fixed plate, the position of the pin in the slotted
plate, width of the leaf, the length of the leaf, the nnuiher of
the leaves, and the angle of the slots. For the greatest
possible aperture the pins should be placed at the opposite
extremities of the leaves, and twenty-five leaves are required.
The maximum aperture obtainable is eighty-two per cent, of
the total diameter of the iris, and no increase in the number
of leaves will give a greater opening. If, however, the
smallest apertures are not required, the number of leaves may
be reduced or a greater aperture obtained.

The length of the scale is governed by the position of the
pin. while by altering the angle of the slot, the division of the
scale can be made more or less even without altering the
total length of the scale ; but the angle of the slot can only
depart slightly from the radial direction without introducing
uncert.iinty in setting.

THE EXHIBITION OE THI-: ROYAL PHOTO-
GRAPHIC SOCIETY.— The Royal Photographic Society
will hold its Annual Exhibition during the month of May,
at Prince's Skating Club, Knightsbridge.

In addition to the usual Pictorial Section. Section 2 will be
devoted to photographs selected for their technical excellence :
Section 3 to colour photographs, including transparencies by
the screen-plate processes; Section 4 to Natural History
photographs ; and Section 5 to Scientilic photographs.

As Sections 4 and 5 are of special interest to the readers
of this column it may be desirable to give the names of the
members of the selecting committees of these Sections, who
will both select the pictures to be hung and award medals.
The judges for Section 4 dealing with Natural History will
be Messrs. W. Earren, F. Martin-Duncan, O. G. Pike and
Dr. Erancis Ward ; while those for Section 5, which consists
of photographs showing the application of photography to
scientific objects, such as photo-micrographs, spectra, astro-
nomical phott)graphs, and radiograms, will be Dr, W". Deane
Butcher (X-ray work), Messrs. Chapman Jones. J. W.
Ogilvy (photo-micrography), W. Shackleton (astronomy),
Major-General Waterhouse, and the writer.

Pictures must be sent in by Monday, April i4th. Entry
Eorms and Regulations can be obtained from the Secretary,
35, Russell Square, W'.C.

PHYSICS.

By A. C, G. Egerton, B.Sc.

GENERAL. — There is so much that is of very great
interest in the physical papers that have recently been
published that it is quite diihcult to choose those which are of
the greatest general interest and demonstrate the advance
that is being made in the various branches of physics. Lord
Rayleigh has been investigating the perception of colour. Sir
J. J. Thomson is [jerfecting a means of analysing the nature
of a highly rarefied gas which he came upon in his studies of

positi\i' rays. Sir William Ramsay and Dr. R. W. Gray have
accomplished a wonderful feat in weighing the emanation of
radium. These are a few instances of the great activity that
prevails in every branch of physics.

NATURE OF THE X-RAYS.— There is considerable
controversy at the present time about the nature of X-rays.
Professor Bragg advocates the view that the X-ray and the
7-ray emitted by radioactive substances, consist of an electron
bearing with it a circumscribed positive electrification
sufficient to neutralise the negative charge — this has been
termed a " neutral pair." The older view, which originated
with Sir George Stokes, was that the X-ray was an ether pulse
travelling outwards and with ever-extending front. On this
idea, as the distance from the source increased, so the energy
at any point on the front of this spasmodic wave decreased.
The X-rays and 7-rays give rise to secondary rays when they
fall upon substances ; and these rays consist of 1^ particles.
/i particles are electrons such as radium ejects ; they are
precisely similar, though more rapidly moving, to the kathode
rays obtained when the electric discharge is passed through
vacuum tubes. Now it is found that the X-rays and especially
7-rays are able to liberate these secondary rays and to ionise
the gas through which they pass at considerable distances
from the source. This fact is difficult to explain on the pulse
theory, but it is what would be expected if the X or 7-ray is a
discrete particle moving at a great speed, comparable with
that of light.

Professor Bragg discussed this most interesting question in
his lecture on the kinetic theory of a fourth state of matter at
the Royal Institution, on January 27th. He pointed out a
similarity between the molecular kinetic theory, which deals
with the collisions and motion of molecules, and the motion of
the radiations from the radioactive elements — a./i. 7 rays — and
of X-rays. There are strikingdift'erences and striking similarities.
Molecules, when they collide with each other, do not inter-
penetrate, but rebound when their spheres of influence touch.
The a particle or other ray is able, in virtue of its small size
and extreme velocity, to penetrate the atom it meets. The
effect of the penetrated atom on the a or ^* particle is such that
knowledge of the internal arrangement of the centre of force
inside the atom may be obtained.

The resemblance between the motion of molecules and that
of these rays is not only that they both move in straight lines
and are darting about to and fro with great speed and are
undergoing frequent encounters, but also it appears that in
each case the sum of the energies of the colliding particles is
the same before and after impact. An a particle, for instance,
collides with an atom — the particle is moving with such
velocity that although the atom abstracts part of the energy of
the particle, yet the a particle (whether it be the same or
another) emerges in the same direction, and with a kinetic
energy equal to that of the original particle, less the energy
absorbed by the atom. The latter quantity is proportional to
the square root of the atomic weight — a remarkable fact,
l-^ventuallv the a particle is so slowed down by collisions that
it is easily deflected from its course on an encounter with an
atom and moves in a more random fashion, splitting up the
molecules of the gas it encounters into electrically charged
" ions."'

It appears that the secondary rays produced by X-rays are
formed according to the same law of equal energy before and
after impact, and it would follow, thus, that their nature is
probably discrete ; and further, since they are undcflected by
magnetic and electric fields, that they are neutral particles.

But ultra-violet light has the pow-er of setting free fi particles
from metals on which it impinges, and it has long been
considered to consist of waves of short length.

Professor Bragg's theory cannot yet be considered to be
(luite complete.

THE ULTRA-VIOLET RAYS.— Professor R. W. Wood
has come across a curious phenomenon which he has recently
described in the Philosophical Magazine. He finds that if
a condenser spark is passed between aluminium terminals and
the direct light is shaded from the recipient of the light,

March. 1911.

KNOWLEDGE.

115

whether it be the eye or a quartz photographic leus, that a
violet glow is visible in the air in the neighbourhood. It
appears that this glow cannot be accounted for by either
fluorescence of the gas in which the spark occurs, or by the
scattering of the light by dust or moisture particles. The
phenomenon is very curious.

The ultra-violet rays are obtained in profusion from the
mercury arc, pro\ided the walls of the tube are of Jena
■' Uviol " glass or quartz : in fact, the rays from these lamps,
unless cut off by glass, by which they are absorbed, are most
injurious to the eyes. It appears that one single wave-length
of the light is capable of penetrating the cornea of the eye and
of doing the mischief.

MM. Urbain, Seal and Feige have devised a mercury lamp
which gives a pure white light. Taking advantage of the high
melting-point of tungsten they have employed an arc between
mercury as kathode and tungsten as the positive pole of the
arc. The arc is maintained in a vacuum, and the tungsten
is only slightly separated from the surface of the mercury.
The tungsten gets white hot. while the usual good efficiency
of the mercurj- vapour lamp is attained.

AFTERGLOW IX \ACLLM TUBES.— The Hon. R.J.
Strutt has been investigating with great skill the glow obtained
in "vacuum" tubes containing air, which sometimes occurs
after the electric discharge is turned off. He removed the
air from the neighbourhood of the discharge, and passed it
into a tube, where he could observe the glow and examine the
conditions which prevented or improved it. He found that
those substances which destroy ozone prevented the production
of the glow, and. further, that it was necessary to send a
discharge through the air before the glow would appear, even
if ozone had been added. In this way he has shown that the
effect is due to both ozone and nitric o.xide. and is merely a
luminescence due to chemical combination, presumably of the
nature of the glow obtained on the oxidation of phosphorus.

Mr. Strutt has found more recently that similar most striking
glow phenomena are obtained with nitrogen, a blue glow-
being obtained in the presence of iodine, while metals exposed
to this nitrogen give out their line spectra.

THE ANNUAL GENERAL MEETING OF THE

PHYSICAL see I ET v.— Professor Callendar, F.R.S., at the
.Annual General Meeting of the Physical Society, on Friday,
February 10th, read a most interesting address on the
" Caloric Theory of Heat." He dealt with the much-over-
looked and misrepresented work of Sadi Carnot. Carnot
began his investigations with the purpose of finding what
advantage would be gained by using working fluids other than
steam in engines. He was led to the consideration of an
ideal heat engine, and showed that if no direct transference of
heat occurred between bodies at different temperatures, the
transformations of heat and motive power were reversible in
such a " cycle." He found that the efficiency of such an
engine (or the ratio of the moti\e power to the quantify of
heat which produced it) was the maximum possible, and was
independent of the working fluids used. By applying the
Caloric Theory of heat, Carnot was able to deduce all the
relations between heat and work in reversible processes, and
to forestall the subsequent determinations of the mechanical
equivalent of heat, by utilising the somewhat rough experi-
mental data which were at his disposal.

The idea of Caloric is similar to the idea of quantity of
electricity ; if all electrical calculations had to be made from
considerations of electrical energy, instead of picturing a
quantity of electricity passing from one potential to another,
there would be much complication. In the same way, a
conception of (juantity of caloric passing from one tempera-
ture to another, besides that of the energy equivalent to such
an operation, would be valuable in simplifying the underlying
notions of that somewhat abstruse subject, thermodynamics.
Caloric is only another name for Rankine's " Thermodynamic
Function," or Clausius' "Entropy." It would be well to
point out that the " Calorie " is a measure of thermal energy,
which must not be confused with the '" Carnot." or unit of
quantity of caloric.

Professor Callendar's study of Carnot's work will make it
possible to give the student a less abstract conception of heat.

The addresses of the officers of the Society, previous to the
reading of the President's address, testified to the flourishing
condition of the Society and to its great activity, while it was
hoped that many would be led to share its Tiiary advantages
and become members.

ZOOLOGY.

By Professor J. Arthur Thomson'.

RIGHT AND LEFT-HANDEDNESS.— After all the

discussion on this subject it is rather surprising to hear an
anatomist of the rank of Karl von Bardeleben saying that
our ignorance on the matter is shameful. We cannot state
percentages for different races : we have done little in ' the
wav of distinguishing different degrees of left-handedness ;
and we do not know how it is that right-handedness has
become so predominant in mankind. Perhaps, one sometimes
thinks, each species has its particular asymmetry, just as many
great types have. The gibbon and orang are right-handed ;
the gorilla and chimpanzee are left-handed. To point to
asymmetry in the brain, e.g., the stronger backward protrusion
of the left cerebral hemisphere, except in typical left-handed
people, shifts the problem without solving it. Professor von
Bardeleben gives the interesting piece of information that
there were last year 119101 in the German army ten thousand
three hundred and twenty-two left-handed men. Only 3'88 per
cent., however '.

FERTILE HYBRIDS BETWEEN BISON AND
DOMESTICATED CATTLE.— E. Iwanoff refers to the
estate of F. E. Falz-Fein, " Askania Nova," where a
number of half-breeds ha\-e been produced by crossing
Bison ainericanus with domestic cows and with the
European Bison {Bison bonasits or eiiropaeiis). Others
have been produced — " Three-quarters American Bison and
one-quarter domestic Bos taurus, and one-quarter American
Bison and three-quarters Bos taurus." The fertility of the
half-breed bison females has been proved. They produce
offspring to both .\merican bison and European bison. The
male half-breds have sexual instincts, but there is no proof of
fertility. But the male of three-quarters bison blood seems to
be fertile with the domestic cow\

OVIPAROUS AND VIVIPAROUS.— It is said that some
snakes, such as the grass snake, normally oviparous, may
become viviparous in the comfortable conditions of captivity.
That is to say tfor the old terms are as bad as they are
difficult to dislodge), the eggs may hatch inside the body
instead of outside. E. Roubaud has recently reported an
interesting parallel case in insects, namely one of the flies,
Musca corvina Fabr. In tropical .\frica this fly is constantly
viviparous all the year round, and at inter\als of four days or
so. It can continue this reproductive regime as long as the
average temperature is not less than 30 C. Now the interest-
ing point is. that according to Portchinsky. the fly is always
oviparous in the north of Russia, laying twenty-four eggs,
while in the Crimea it produces a large larva viviparously at
the end of spring and in summer. The author calls this
" seasonal and climatic poecilogony."

BRAIN OF A SILVER-FISH.— Comparatively little has
been done in the way of comparing the brains of different
kinds of insects. One, therefore, welcomes the study which
Otto Bottger has made of the brain of the little wingless
insect, Lepisiua saccharoides, not uncommon in houses,
and popularly known as the " silver-fish." It is something of
an achievement to be able to present a picture of the minute
structure of the brain of such a tiny creature, and it is
interesting to notice the investigator's general result — that the
brain of this type is in many ways quite peculiar. Indeed it
shows parts which have not been seen as yet in any other
insect.

LARVAL MANTIDS MIMICKING ANTS. — From a
pale emerald-green, walnut-sized nest, sent to the Zoological

116

KNOWLEDGE.

March. 1911.

Society from the Gold Coast, there emerged a crowd of youn.t;
mantids. about four milUuietres in length, which. ""uhen crawling
about the case, looked exactly like a crowd of black ants, their
rapid darts and -pauses recalling irresistibly the busy method
of progression so characteristic of these Hymenoptera." Mr.
R. I. Pocock. the Superintendent of the Gardens, observed them
carefully, and noticed that it was only when in motion that
they resembled ants. When at rest they were seen in their
true colours — as Mantises. "raising the fore part of the body
and head, folding up their fore-legs, and every now and then
swaying gently from side to side, as if rocked by the wind.
While thus employed they were seen to be procryptically
coloured.'" That is to say, they were inconspicuous. Mr.
Pocock has analysed the resemblance to an ant. and finds that it
is p.artly due to the blackness of the underside of the abdomen,
and partly to the habit the moving insect has of curling the
posterior half of the abdomen up like a scorpion's tail. This
altered the proportions and shape, and in a curious way a
white spot on the prothorax simulated an ant's waist. When
the young insects attained a length of se\en millimetres they
lost their ant-like look. Mr. Pocock also directs attention to the
conspicuous larva of a Ceylonese leaf-insect, closely resembling
a distasteful beetle I Lycostoiuus gcsfroiK which is also
mimicked by two bugs and a motli.

COPEPODS .\XD ALCYONAKI.AXS. — Colonies of
Alcyonarians often harbour small parasitic Copepods. which
are known as Lamippids. They are very distinctive little
creatures, characteristic in their buccal armature at one end,
and in their caudal fork at the other. They have been recentlv
studied systematically by A. de Zulueta. and the result shows.

what is so often true of parasites, that each species of Lamippc
has its particular host. Some hosts may harbour two or
three species, but no species occurs on two different hosts. It
is impossible not to wonder whether in these cases, and for
others like them — Xematode worms, for instance — there may
not be "modification species." whose characters are directly due
to their immediate environment. It would be interesting to trans-
plant some young Lamippids from one Alcyonarian to another.

SIMULACRA VITAE.— If a weak solution of gelatine is
spread on a slide and tiny drops of ferrocyanide of potassium
are put on at intervals of five millimetres by means of
a pipette, beautiful simulacra of nucleated cells are produced.
If fragments of calcium chloride are dropped into sixty grains
of silicate of potassium at thirty-three degrees, sixty grains of
saturated solution of carbonate of soda, thirty grains of
saturated di-basic phosphate of soda, and distilled water up
to a litre, then beautiful phantasms arise — " osmotic growths "
— like mushrooms and moulds and corals and shells.
Professor Stephane Leduc has given much time to these
interesting and fascinating simulacra vitae. and discusses
their importance in a recent book (" Theorie Physico-
Chimique de la Vie." Poinat, Paris, 1910). There are. of
course, osmotic phenomena in organisms, and the more they
are studied the better, but it appears to us to be giving an
entirely false simplicity to the facts to declare that biology
is a subdivision of the physico-chemistry of fluids. This is
a survival of the discredited materialistic superstition, and
to credit the artificial osmotic growths with nutrition,
assimilation, irritability, and a power of development, is a
bad instance of an assertion that outstrips its evidence.

THE LEONID FIREBALL OF NOVEMBER i6th, 1910.
Bv W. F. DENNING. F.R.A.S.

The Moon being full at the epoch of the Leonid shower in
1910, it appears to have been but slightly observed. .A very
brilliant member of the stream was, however, seen by various
persons who were watching the total lunar eclipse on the night
of November 16th.

Mr. J. Cranston, of Giffnock, near Glasgow, saw the meteor
at 12" 27". It fell from a few degrees to the right of Algol,
almost vertically downwards, bursting in Andromeda. The
direction was from between Capella and L'rsa Major. It left
a tail visible for se\era! minutes. The length of path was
about 26 , and when bursting the meteor appeared to equal
the size of the moon.

Mr. W. B. Ogilvie, at Greenock, N.B., gives the time as
12*' 26". He saw an intensely luminous streak stretching
from above the stars, 35, 39, 41 Arietis towards Capella. The
streak was broken and the brighter portion lay west of
Capella. It was visible to the unaided eye for five minutes.

Miss Helen M. Metcalfe recorded the meteor at Kildare, and
Miss Rose Atkinson from Pitlochry, while correspondents to
the English Mcchtjiiic also described its appearance.

There is no question but that the meteor was a brilliant
Leonid passing over Scotland and the north coast of Ireland.
Its height was from ninety-one to forty-five miles. The radiant
point was near 150°-|- 23° in the well-known "Sickle of Leo."

At and near Glasgow the fireball presented a splendid
appearance, and the intense light accompanying its sudden
outburst astonished many persons. The apparition of this
fine Leonid is interesting as proving that the shower returned
in 1910, though possibly under a feeble aspect. Thirty-
three years ago, viz., in 1877, November 10th to 13th. I
recognised it, but it was very feeble.

Tempel's parent comet of the Leonids is now not %ery far
removed from its aphelion outside the orbit of L'ranus. Such
meteors of this stream as are noticed during the few forth-
coming years will, therefore, be at nearly the opposite part of
the orbit to the comet. It is known, how-ever, that the stream
is an annually visible one, and that the meteors are distributed
right around the ellipse, though only feebly so in certain
sections of it.

Mr. J. McHarg. of Lisburn, near Belfast, reports that at
midnight (Dublin time) he observed a bright flash, and looking
towards the stars of Ursa Major he remarked a short, broken
meteor-streak, about 1° above the stars S and 7. The direction
of this streak was from the radiant of the Leonids, and a
small Leonid shooting star passed through Ursa Major at the
time the streak from the fireball was suspended there. It
remained three minutes, the portion near the star S Ursae
Majoris mo\ing downwards to below 5, while the westerly
section formed a small patch of nebulosity, and continued
stationary about 1 above 7.

The position of the streak was evidently influenced by air
currents of different velocities and directions in the upper
regions of the atmosphere. The singular streak left for three
hours by a fireball on February 22nd, 1909, exhibited similar
phenomena ; while the ends appear to have retained nearly
the same position for the long time, the central parts drifted
N.W. at the velocity of ninety or one hundred miles per hour.

Mr. C. L. Brook, of Meltham. near Huddersfield. obtained
an excellent view of the fireball, and as he is an experienced
and accurate meteoric observer his record is of special value.
He places the beginning of the luminous course in the region
of a Draconis and the whole path as from 205° + 60° to
295°+3S°. The meteor burst at 293"-4-44= 20' and a small
section of the streak remained visible without drifting much
for five minutes. The meteor ended with a minor explosion
before it reached v Cygni.

In deducing the height and length of path of the object, I
have had to revise some of the observations. I think the
best real path obtainable is that the meteor passed over the
sea near Berwick, to nearly above Edinburgh and Glasgow,
and westwards over Kintyre, ending north of Rathlin Island
off" the north coast of Ireland. Several of the observers
place the end further west, while Mr. Brook's record indicates
that it began earlier in its flight and decidedly east of Berwick.
However, a length of flight of one hundred and sixty-five
miles and a velocity of thirty miles per second satisfies the
observations and cannot well be far from the actual course.

Figure 1.

(Note. — The line A. B. may just as appropriately be drawn below the circle, or cutting through it.
It is here made tangential merely to simplify the measurements to which reference is made.)

A SIMPLE METHOD OF CONSTRUCTING A
HORIZONTAL SUN-DIAL.

Bv CH.\RLES E. BEXH.VM.

reful

into

equal

Strike out a circle on a piece of paper. The size
is not important, but as some guide it may be
mentioned that it will be found that the height of
the gnomon of the dial will be a little less than the
radius of this circle.

Divide the circle very
parts, and at right
angles to one of these
radii draw a horizontal
line (AB, Figure 1)
tangential to the cir-
cumference. Cut the
paper along this line,
and produce the 11
nearest radii to the
cut edge as show n.

On a larger piece

Figure 2.

of paper draw two lines at right angles in the form
of a T, and to the top line of this T apply the
cut edge, so that its central line touches the centre
of the top of the T- Mark off on the top line of
the T all the points where the produced radii meet
the cut edge.

Draw two lines meeting at an angle equal to the
latitude of the place for which the dial is to be
constructed, and form a right-angled triangle
(ABC, Figure 2) with this angle for its acute
angle C, and with the length of the side AB
exactly one radius of your circle. Mark a point
on the upright line of the T exactly the length
of BC from the top. Rule lines through all
the points on the top line of the T to this point
on the other line, and produce them on through the

point. TliL-se will be the hour lines of the dial plate
and must be numbered — 12 for the central one,
with 11, 10, 9, and so on, in order on the left, and
1. 2, 3, and so on, in order on the right. A line
parallel with the top of the T will form the hour
line for the two sixes. Of course it is not necessary
to number the hours further than S in the evening
or before 4 in the morniu!

required the original circle mus

If half hours are
be divided into 48
instead of 24 : if quarters, 96 parts.

The gnomon must be a triangle of metal corres-
ponding with the triangle of Figure 2, the base being
BC. the point B at the head of the T and the point
C where the hour lines intersect.

This simple method of dialling will incidentally
suggest the curious form necessary for a dial at the
latitude of the equator — 0 degrees.

In this case, the angle at C being 0 degrees, the
line AC, instead of sloping downwards, would have
to be parallel with the dial face, so that a rectangle
would take the place of the triangle for the gnomon.
The hour lines, having no point to converge to,
would also run parallel w ith the top of the gnomon,
and the dial would take the form show n in Figure 3.

Figure .;.

Form of Horizontal Dial adapted to the latitude of
the Equator.

117

THE CENTENARY OF URBAIN JEAN JOSEPH

LE VERRIER.

Hv F. A. KMLLAMY. Hon. M.A.. F.K.A.S.

On March 11 th. 1911. the centenary of the birth of
this most eminent astronomer of the last century
will be celebrated. A few words u[)i)n this man
may not be amiss to the present generation, seeing
the time that has elapsed since his death. He
was a student at the Ecole Polytechnii]iic at
Paris when from twenty to twent\--two }-ears of age.
His earh' work was in the domains of chemistry and
engineering : but his first astronomical paper was
not communicated to the Academ\- of Sciences until
1839, on the important subject of the Secular
Variations of the Elements of the Orbits of the
Seven Major Planets. Further researches upon the
same subject were made in the next \ear or so : the
papers are printed in the Coiiiniissaiicc dcs Tciiipf;
for 184,5 and 1S44. These memoirs seemed to have
excited his energies; for, from 184,5 until 1877, he
produced an incessant stream of highly-important
researches, entailing prodigious labour upon the
Theory of Mercury. 184,5 (revised in 1859) : the
Theory of Uranus. — the three famous memoirs
were presented to the .\cadem\- in 1.S45 and
1846 (reinvestigatcti in 18/4): Thenrx of the
(Earth) Sun. in 1853 and 1S5S: Theor\- of \'enus.
1861 : Theor\- of Mars, INfil : Theor\- of Jupiter
and Saturn, in 187Jand 1873; and the Tlieor\- of
Xeptune, 1875 and 1877 ; these memoirs and the
tables based upon them are to be found in the
AiiiujIl-s lie r Ohscrvafoirc c/l- Paris, tome I\'-XI\',
and form an imperishable monument to him ; the
movements and positions of these bodies given in the
nautical almanacs of various nations ha\ e for many
years depended upon these tables. C)t all these
separate in\'estigations, those relating to Uranus stand
out most prominenth' before the world, whether it
be considered astronomicalh' or generalh-. Bou\'ard's
tables of Uranus, printed about 1821. \\ere generalh'
used : and it was the increasing difference between
those calculated places and the observations which
caused Le Verrier, it is said by Arago's request,
to commence his researches which ultimateh' led to
the discoverx' of a new and more remote niaj(.)r
planet, Neptune, in the September of 184(:). (These
memoirs were published in the Cuniuiissaiicc dcs
Temps for 1849.) The subject of the visual
discovery In Dr. |. (i. Galle was recently referred
to by the writer, in "KNOWLEDGE" for last August
and September, wherein it was shown that the
receipt, by Galle, of a letter from Le \'errier in
September, 1846, asking him to look for a planet in
a particular region, which he indicated closely, (ialle
was soon able, on September 23rd. 1846, by the aid
of one of Bremiker's star maps, assisted b)- d'Arrest's
suggestion and help, some say, to detect an object
which had a disk and which proved to be the new-
body sought for by Le Verrier : Le Verrier's letter
of October 1st, tlianking Calle. is delightful to read.
This triunuirate, Hreniiker. Le \'errier. and Galle.

all assisted in the discover\- : and the following facts
are worth\- of attention being drawn to them.
Bremiker, the star-map maker, was born in 1804.
and died almost suddenh- on March 26th, 1877,
a generation ago. (Parenthetically, it ma\- he added
that Heis, also a star-map maker was born in
1806 and died on June 3()th. 1877, also suddenly).
Le Verrier, born on March 11th. 1811, died e.xactly
thirty-one years after Galle had visually discovered
the planet Neptune, September 23rd, 1877. Galle.
born a year later than Le \'errier. on June 9th, 1812,
lived for sixt}'-four years, or nearly two generations of
astronomers, after the discover\- of Neptune, and for
a generation after Bremiker and Le \'errier.
Bremiker and Galle were both elected Associates
of the Royal .Astronomical Societ\- on the same day,
May 12th'. 1848.

In addition to these immense and laborious
investigations Le Verrier's attention was particularly
attracted to the study of the orbits of comets,
especially those of Lexell (though discovered by
Messier). Faye, and De A'ico (the memoir on Lexell's
Comet is considered a classic work) ; he gave much
time to these calculations and achieved what others
had hitherto failed to accomplish.

For his grand work he was twice awarded the gold
medal of the Royal Astronomical Societ\' : ujjon the
first occasion it was in 1868 for his researches on
Mercur\-, \'enus. Earth, and Mars: and in 1876. the
year before his death, when his eminent colleague in
similar work on the planet Uranus, Professor J. C
.\dams, gave a fine address in presenting the medal
for researches on the next four major jjlanets. It
is a strange fact, looking down the list of medallists
from 1846-1876, that neither the theoretical nor the
visual discoverer of a new major planet should be
thought worthw by the members who formed the
R.A.S. Councils during that period, of the award : it
is ex'en more strange when one sees the comparatively
trivialoralmostforgotten work for which some obtained
the medal. Was it jealous\' ? Certainly in 1848
they obtained a clean slate by giving testimonials
freely, but the merits of the others pale before the
immensely superior claim of Le \'errier : it w as
small honour to him to see his name in that 1848
list, and wh\' were not Galle's and Adams" included ?

Le \'errier was appointed Director of the National
Observatory, at Paris, in 1853, when Arago died, but
left in 1870, owing to difficulties with his colleagues
there : he, however, was re-appointed in 1872, and
remained Director until his death in 1877. His
health was poor for some months before his death,
but he was cheered greath' by Galliot's assistance in
getting the computations and in printing the tables
of Neptune completed shortly before his death. He
was a Grand Officer of the Legion of Honour, and
so had a semi-militar\' fimeral to the cemetery of
Mont Parnasse. Paris.

1)S

REVIEWS.

ARCHAEOLOGY.

ASTRONOMY.

British Cosfmiic lUiriiig Xinctecnth Centuries. — By Mrs. Researclies on Tlie Chemical Origin of Various Lines in
Charles H. .Ashdown. 376 pages. 459 engravings. Solar and Stellar Spectra. — By Fr.^nk E. Ba.xaxdall,
119 plates. gi-in.Xfi^.in. A.R.C.Sc. 77 pages. " 12-in. X 9i-in.

(T. C. and E. C. Jack. Price IS 6 net. I

side

An

We do not pay enough attention in tliis country to tliat
of archaeology which deals with the
development of the industries of the people,
especially as these are concerned with the
details of everyday domestic life. It is
true that considerable interest is taken in
the history of dress, and this, perhaps, for
special reasons, but we still have no folk
nu:seum in which we can refer to the actual
clothes themselves. The task of getting a
proper series together becomes increasingly
difficult as the \'ears go by. When, even-
tually, a serious attempt is made to repair
the deficiency in our national collections
we shall, no doubt, liave to depend a
great deal on careful reconstructions such
as Mrs. Ashdown has made for the purpose
of producing the coloured illustrations
which embellish her book. As these have
been taken, with the help of photography,
from real people — and we cannot imagine
that the features of English men and women have changed
greatly in a few hundred years — we get from the pictures a
better idea as to the
effect of the costumes
than is possible in any
other way.

It is very interesting
to the student of the
past to study old cos-
tumes that survive at
the present day — say,
like those of the Sister
of Mercy and the
Blue - coat Boy, and
see from what chap-
ter of history they are
taken.

The exaggerations in
dress that are so
common throughout history
olden times cannot seem to us to be any
pictures of those of the present will
appear to our descendants. When the
clothes are seen on li\ing persons their
ridiculousness is not always quite so
obvious as it is in the illustrations of a
book or it is possible that the Goddess
of Fashion would not have quite so many
worshippers.

Clothes proper are not the onl\-
things which are presented to us by
Mrs. Ashdown. and the method of
riding by ladies which we have chosen
for illustration is a good instance.
Women of the lower orders, and
ladies when hunting or in a hurry.
rode astride, but the side saddle was
used from Anglo-Saxon times onwards by
the quality.

Anglo-Saxon lady ridin
a side saddle.

A lady riding astride when hunting in the reign of Richard II

are amusing to us. but those of
more idiotic than

Ladies using the side saddle
(14th Centurv).

(Wyman iS; Sons, for the Solar Physics Committee. Price 4 6.)

.A. collection of six papers, the first giving the results of a
comparative study of the spectra of the
sun and lower type stars, in relation to the
sunspot spectrum. During the seven years
the work has been in progress, several
papers bearing on the subject have been
published from Mount Wilson Observatorv
and are referred to, and the results com-
pared with those obtained at Kensington.
The stars compared with the sun are
Capella and Arcturus. The former yields
a spectrum very like the general solar
spectrum, but the latter is found to be
very similar to sunspot spectra. The
elements which appear to have the largest
share in producing the distinctive spectrum
are vanadium and titanium. The conclusion
is drawn that there are probably nearly
similar conditions either as to temperature
or electrical excitation in sunspots and stars
of the Arcturian class. Further it is
considered that the Sunspots and Arcturus are lower in
temperature than the general photosphere and Capella.

Part II. gives the results of an investigation of the
spectrum of e Ursae Majoris, a star of Sirian type,
but having certain peculiarities. One result is that
the lines of proto-chroinium are found more pro-
nounced than in the
spectrum of any other
known star.

Part III. deals with
the presence of nitrogen
lines in stellar spectra,
detailing the relative in-
tensities of the stronger
lines in the stars ft 7
V. f. t. and I Orionis
It is noticeable that
in spectra of stars of a
higher class than i, or
a lower than ,i. no nitrogen lines are found.

Part IV. consists of lists of enhanced lines in the spectra of
some metals not published previously.

Part V. gives tables of wavelengths of
known lines of use in studying the radial
velocity of stars.

Part \T. brings together in order of wave-
length a number of pronounced lines, met
with in various celestial spectra, but, so far,
not identified with any known terrestrial
substance. The contribution is distinctly
a useful one : the last' part very specially
may be helpful to the laboratory worker —
a list of eighty-two lines to be watched for.
Helium is now a well-known gas, yet for
many years it was only known as a bright
line in the solar chromosphere, very
occasionally recorded dark on the disc.
What may not these eighty-two lines, as
vet unknown, mean ? F. C. D.

TIu'sc illiistratitins are reproduced hy the courtesy of Messrs. T. C. and E. C. Jacl;.

119

120

KNOWLEDGE.

March. 1911.

iXortoit'.f Stiir Atlas and Telescopic Handbook. — By

ARTHt'K P. NoRTO.\. B.A. 20 pages. 16 maps.

lli-in.XSj-in.

(.Gall and Inglis. Price 5 - net.)

This is a star atlas on good paper of convenient size and
weight. The author has evidently taken great care and spent
much time in attaining the production of a useful atlas suitable
to possessors of telescopes of moderate size. A map of the
moon is given as a frontispiece, and x'arious information
relating to the relative magnitudes of stars, terms and abbre-
viations used in astronomy, notes on star nomenclature, sun.
moon, planets, stars, nebulae, comets, and meteors : care
and use of the telescope, hints on observing, and Arabic
names, are given on the first nineteen pages; then follow
si.xteen maps, or rather eight double maps, for the northern
sUy is given on the right-hand side, and the southern skv is
continued on the left-hand side. On the back of each map is
abundant information concerning tlie principal double stars,
variable stars, clusters and nebulae. There is also, at the
beginning, a replete index of contents and. at the end, an inde.N
to the constellations with the dates of culmination for 9 p.m.
and midnight. The obvious faults are three : ia) the maps
err by containing too much information in gi\ing star catalogue
references, no doubt convenient for day use, but tending tn
render the stars on the maps less conspicuous in a dim light at
night ; ib) giving the maps for epoch 1920-0 is needless for
such small scale maps ; much better have made the epoch
1900-0, they would then have agreed with the International
Survey maps and catalogues, and still have been sufficiently
accurate for general use for many years to come; (c) binding
the equatorial portion of each map in the back of the atlas is a
serious inconvenience and loss of an important part of the sky ;
a different form of binding, an unprinted space in the fold of
each double map, or the mounting of the maps on guards would
have prevented this loss. F. A. B.

BIOLOGY.

Si(rvival and Reproduction — .4 Xac Biological Outlook. —

By Hermann Reinheimer. 410 pages. Si-in. x 5i-in.

(John M. Watkins. Price 7/6 net.)

This book is a continuation of " Nature and Evolution," in
which the writer claims to have propounded a broader and
more apposite theory than that of " natural selection " to
explain evolution, and in the introduction we are given ninety-
eight points and propositions which are contained in the
previous volume. Mr. Reinheimer, so far as we are able to
make out, seems to have set up in his mind some sort of rules
of behaviour to which he considers that creatures should
conform. For instance, after comparing beetles with the less
numerous lepidoptera, he says : — " Now the construction that I
wish to place on these facts is to the effect that as soon
as the law of animal alimentation is seriously infringed
— as soon as animals habitu.'ite themselves to feed on animal
instead of vegetable matter — multiplication of individuals and
frequently of groups termed species proceeds at a dangerous
and chaotic rate (pathologically). in\-olving violent clashes and
struggles between organisms w-hich are of their own making." If
this be true we should not expect a declining birth-rate among
meat-eating people. In another place he presents the case of
cannibalism among whelk embryos as a " striking picture of
parasitic retribiUion." and with this we are asked to compare
"the rectitude of life" in the higher organisms.

Many interesting biological facts are mentioned in the book,
but we are not convinced by the arguments.

BOTANY.

Alpine F/oK-cr.s- and Rock diirilens. — Described by Walter

P. Wright, with notes on ".Alpine Plants at Home," by

William Gka\i;son. 292 pages. 4 coloured plates.

15 figures. 9|-in. X 6j-in.

(Headley Brothers. Price 12 6 net. I

Garden lovers w-ill welcome another helpful volume from

the pen of Mr. Walter P. Wright. Of late years Alpine

plants have greatly gained in popularity, probably owing in
no small degree to increased facilities for travel, and con-
sequent interest in mountain flora. A rock garden has many
obvious advantages, not the least being that the space required
need not necessarily be extensive, and hence, given the
reijuisite knowledge, it is quite possible to possess a successful
and \ery interesting rock garden even in the suburbs.

.Apart from the wealth of information contained in this
book, its great charm lies in the beautiful coloured photo-
graphs of rock plants in their native haunts, which occur
e%ery few pages, the brilliant colouring of the flowers on the
brow n mounts making the volume exceedingly attractive.

GEOLOGY.

Siiiitlisoniiin Miscelliincoits Collections. Vol. 5j. No. 6. —

Cambrian Geology and Palaeontology. Olenellus and

other Genera of the Mesonacidac. — Bv C. D. Wai.cott.

Pages 231-422. 22 plates.

No. 7. I're-Canibrian Rocks of the Boic River Willey.
Alberta. Canada.— IW C. D. \\'alcott. Pages 423-431.

J plates.

Vol. ri7. No. 1. — Ciunbi-iiHi Geology and Palaeontology. II.

.Abrupt .Appearance of the Cambrian Fauna on the Xorth

.Autencan Continent. — By C. D. Walcott. Pages 1-16.

1 Map.' 6J-hi.xgj-in.

(Washington: Smithsonian Institution, 1910.)

These three publications are in continuation of the lifelong
work of Dr. C. D. Walcott on Cambrian and Prc-Cambrian
geology and palaeontology. The first is a complete mono-
graph on Olenellus and its allies. Under the family
Mesonacidae are included the genera Xcvadia. Mesonacis.
Elliptocepliala. Callavia, Holniia. Wanneria, Pacden-
mias. Olenellus. Peachella. and Olenelloides. with thirty-
three sjiecies at present known. Nevadia is the most primitive
foriu : from it spring two lines of descint. one through
Callavia. Holmia. and Wanneria. probably- leading on to
the Middle Cambrian Paradoxides ; the other through
Mesonacis. Elliptocepliala. Paedetiniias and Olenellus,
becoming extinct in Lower Cambrian times with the degenerate
form Olenelloides. .All known species of the Mesonacidae
are confined to the Lower Cambrian. This fine monograph
is illustrated by twenty-t-wo excellent plates, containing tw-o
hundred and fifty-eight figures.

In publication No. 7, Dr. Walcott describes his field work
on the Pre-Cambrian of the Bow Valley. .Alberta. These
rocks are unaltered sediments lying unconformably beneath the
Cambrian, and. as far as known, are unfossiliferous. The
formation names Hector and Corral Creek (in descending
order), are proposed for them, and they are correlated with
the Camp Creek and Kintla-Sheppard series of Montana.
South-Western -Alberta, and South-Eastern British Columbia.

The fascinating topic of the abrupt appearance of indications
of life in the Cambrian period is discussed in the last publi-
cation under review. This paper is Dr. Walcott's contribution
to the debate on " The abrupt appearance of the Cambrian
Fauna," at the eleventh International Geological Congress, at
Stockholm, this year. Brook's views as to the origin of life in
the open ocean are adopted. This pelagic life is believed to
have become adapted to littoral and shore conditions during
the period of .Algonkian continental elevation, which w-as of
sufficient duration to permit of the development of the types
now found in the basal Cambrian rocks. The sediments and
fossils of the Lipalian era (i.e., the period between the forma-
tion of the Algonkian continents and the earliest encroachments
of the Lower Cambrian sea), are absent from our present land
areas, the continents having been high above sea level during
the development of the Pre-Cambrian fauna. The Lipalian
sediments are probably still buried beneath the oceans. This
theory depends primarily on the absence of a marine fauna in
the known .Algonkian rocks, most of w-hich. such as those of
the Cordilleran geosyncline, are believed to have been deposited
in fresh or brackish waters. It appears to depend also on a
rigid acceptance of the theory of the permanence of ocean
basins and continental areas.

Makih, 1911.

KNOWLEDGE.

121

.4 Textbook of Geology. — By P. Lakh. M..\.. F.G.S.. and
K. H. Rastai.l, M.A.'. F.G^S. 494 pages. 134 figures.
32 pl.ites. 5A-in.XS^-in.
(Edward .■\niold. Price 16 ■ net. I

Geological students have long needed a textbook to bridge
the gap between the elementary manuals and such detailed
works as Sir A. Geikie's great treatise. They have their need
satisfied in the book under review, which meets a distinctly
"felt want." In its five hundred pages the student will find
most geological topics dealt with in clear concise paragraphs
informed with the latest results of research. The book is
divided into two parts ; the first, dealing with physical geology,
has been written by Mr. Rastall ; the second, on stratigraphical
geology, by Mr. Lake. The treatment adopted, as acknow-
ledged in the Editor's preface, is frankly Lyellian. In
accordance with this method, petrology and palaeontology are
necessarily dealt with only to such an extent as is required to
appreciate their place in geological science. Their modern
development is regarded as altogether too extensive to be
included in a work on the principles of geology.

We have nothing but praise for that portion of the book
which deals with physical geology. The arrangement and
selection of material is good. Some of the latest results of
research on British rivers, and on North .American glaciers, to
mention only two subjects out of many, are here rendered in an
easily accessible forms, for the first time in an English text book.
The whole section gives evidence of very careful and extensi\e
reading on the part of the author. Similar praise must be
accorded to the stratigraphical part of the book, which is headed
by a good chapter on the often-neglected principles of strati-
graphy. A. welcome feature to British geologists is the
incorporation of the latest results of stratigraphical work in
Wales, Cornwall and elsewhere. Only British stratigraphy is
dealt with, as the scope of the book does not permit the
consideration of foreign deposits. The work is in general so
thoroughly done that it is surprising to find no account of the
recent material development of our knowledge of the great
Dalradian series of the Scottish Highlands by the Geological
Survey officers and others. The plateau lavas of the Carbon-
iferous in Scotland, except in the Garleton Hills, are mostly
very basic olivine basalts, not andesites. as stated on page 371.
In spite of minor defects, we have in this section the best,
fullest and most modern account of British stratigraphy. The
text is illustrated by many excellent plates and informative
diagrams. There are two misprints in a single paragraph on
page xii., and a transposition of lines on page 140, but these
are the only blemishes we have been able to discover in a well-
printed book. The authors are to be congratulated on this
excellent and important summary of geological science, which
should be in the hands of all geologists.

MEDICINE.

Induced CeJl-rcproductioii and Cancer. — By Hugh

Campbell Ross. M.R.C.S.,L.K.C.F. _'91 pages. 125 plates.

9i-in. X6-in.

(John Murray. Price 12 - net.)

In this large and interestingly-written book the author
describes researches which he has recently carried out by a
special and, for the most part, original method, upon the white
blood corpuscles. .A small quantity of blood is spread out on
the surface of a film of jelly, containing stains and other
substances dissolved in it, and the whole is then covered with
a cover-slip and examined. The stain is slowly taken up by the
leucocytes and lymphocytes and various changes are observed
to take place in these cells, depending on the nature of the
dissolved substances. What the writer describes as division
of the white blood corpuscles can be watched on the stage of
the microscope. In the case of the lymphocytes it is quite
possible that these changes may at times constitute a true
physiological dixision: but it would appear probable that the
leucocytes never really divide, as they are fully formed and
specialised cells, and that what the author has observed are
really degenerative changes taking place in cells that are
slowly dying. .-\t any rate, as the writer very justly points

out. no one has previously observed the division of the ordinary
polymorphonuclear leucocyte, though this has been searched
for during half a century. Among other substances, extracts
of decomposing animal tissues have the power of inducing the
above changes in the white blood cells, ar.d the suggestion is
\ery reasonably brought forward that the presence of these
substances may be the deterniining factor of the cell prolifera-
tion that takes place in a healing wound. The last few
chapters are devoted to some theoretical considerations
regarding the cause and cure of cancer.

The book is well written and well illustrated iiy micro-
photographs. Some of the observations described in it have
already appeared in the journals, but do not appear to have
been well received by pathologists generally.

METEOROLOGY.

Sontliern Hemisphere Surface-Air Circulation. — By

WlLl.L\M J. S. LocKVER. M..\. (Cantab.), Ph.D. (Giittingen),

F.R..-\.S. 110 pages. 15 plates 12-in. X9i-in.

( Wyman & Sons, for the Solar Physics Committee. Price 6/-.)

-■^ most interesting and instructive study of air movements
in the southern hemisphere during the winter — .-^pril to
September — months. There appear to be a series of anti-
cyclones, or high pressure swirls or eddies, travelling constantly
eastward. The areas of these vary somewhat, being larger in
winter, and smaller in summer. The centres in winter
travel nearly alon.g parallel 34 south, the circulation of the
eddy being in the direction S.E.N. W. They appear to
tra\el over land at the mean rate of about 1 L • 5 daily
in longitude, but over the oceans at about 9 '-2, giving a
mean rate of 10' -7 per da\- around the earth, completing
the circuit in 33-6 days. The path of these systems is
instructive. They seem to follow almost truly along the
line of latitude across the wide expanse of the Pacific
Ocean, then, when met by the Andes chain near the
west coast of South .America, they turn very abruptly south,
and after breaking through the mountains curve north again,
and travel direct over the .Atlantic, but follow the coast-line
south of Africa. Thence direct across the Indian Ocean and
.Australia. .Again, over the South Pole there is another anti-
cyclonic region, not indeed having the pole quite central, but
crushed down, as it were, directly below South .America.
Between the anti-cyclonic systems there travel in the same
direction, but rotating S.W.N.E., a series of low pressure
eddies or cyclones. The path of these is near latitude 60
south. For the " reason why " of these movements we
cannot do better than ad\ise those interested to study the
memoir. The results are obtained from the observations
made at about fifty stations, supplemented by the work at
eight stations occupied by Antarctic expeditions. In going
through the volume it seemed unfortunate that there could be
no report from Tristan Da' Cunha, which would be like a
connecting link between America and Africa.

PHYSIOLOGICAL CHEMISTRY.

Practical Physiological Chemistry. — By R. H. .Aders
Plummer, D.Sc. 270 pages. 10-in. x 6i-in.

(Longmans, Green and Co. Price 6 - net.)

Physiological Chemistry, it will be remembered, deals with
the composition and properties of those carbon compounds
which are constituents of living matter, and are concerned in
\ital processes. The Chemistry of the chief organic con-
stituents of the human body and its secretions, and of the
principal food-stuffs, are dealt with, from the practical stand-
point, in the work before us. The present volume was, in
fact, as we are reminded in the preface, originally compiled as
a handbook for the practical work hi Physiological Chemistry
at University College, London. The text is conveniently
arranged in paragraphs with headlines, while the descriptive
matter is printed in large, and the practical work in smaller,
type, and the author's name is a sufficient guarantee that
every statement therein contained is in accordance w'ith the
most recent researches ui this rapidly extending science.

122

KXOWLKDr.i:.

March. IQll.

A good many excellent illustrations of the microscopic
appearance of crystals of various organic substances are
reproduced in the volume, and a coloured plate of the spectra
of haemoglobin and allied compounds forms a useful frontis-
piece. A list of reagents of use in Physiological Chemistry,
with the exact strength and mode of preparation of each, is
given in the appendix, and there is also an excellent index.
The volume is destined to become the standard class-book of
Practical Physiological Chemistry.

PHYSIOLOGY.

Preliminary Physiology. — By William Xarkamork. F.L.S.

220 pages. 7i-in. X 5-in.

iMethuen lS: Co. Price 3 6.)

Nowadays every elementary teacher of e\ery elementary
subject regards it his duty or his privilege to bring out an
elementary text-book in which to display his elementary
knowledge of that subject. Such a book we have now before
us. The elementary error that " at the moment of swallowing

. . . the epiglottis closes over the glottis." is repeated
throughout its pages and even figured. Again, on Page 72 we
read that. " Many of the white corpuscles contain more than
one nucleus," the truth being that, while all the white cor-
puscles are uninucleate, most have a more or less branched
nucleus, which might appear multiple to the casual observer.
In the preface we read that. " The illustrations for the book
have been prepared especially to help the teaching in the te.xt."
In this they succeed admirably, for many of them are equally
inaccurate. The diagram of the nose on Page 172 gives one
an entirely false idea of its bony structure, and the imagina-
tive picture of the epiglottis neatly closing over the glottis,
shown on Page 97, has already been referred to.

The one redeeming feature of the book is the series of
micro-photos of animal tissues beautifully reproduced in the
form of plates. Some of these, notably those representing the
minute structure of skin, bone and muscle, are really excellent
and worthy of a place among better surroundings. There are
so many admirable text-books of elementary physiology, that
we find it impossible to recommend the example now before
us.
The Physiology of Rcproili(cfioii. — Bv Franxis H. .\.

Marshall. 706 pages. 154 illustrations. 9-in. X6-in.
(Longmans, Green & Co. Price 21 - net.l

This book is a carefully-written and most exhaustive treatise,
dealing with the times at and periods during which various

animals breed, and the changes that take place in the repro-
ductive organs, including those of the female when pregnant.
Comparisons are drawn between man and other animals,
and the birth-rate is discussed. An interesting chapter deals
with the factors that determine sex, and the book concludes
with a consideration of the phases in the life of the individual.

Of Distinguished Animals. — By H. Perry Robinson.

234 pages. 56 illustrations. 75-in. X 5|-in.

iWiUiam Heinemann. Price. 6 - net.l

Portions of this most interesting volume appeared in the

Tii)ics during 1909. under the title of " Studies in the

Zoological Gardens." Those who enjoyed the articles then

will welcome their publication in book form, more especially

with the addition of the very excellent photographs taken in

Regent's Park. All lovers of animals will read with great

pleasure the racily-told anecdotes concerning the wild creatures,

while the amount of information given anent them will cause

future visits to the Zoo to be more enjoyable than ever.

Reptiles of the World. — By Raymond L. DIT^L\RS.

373 pages. 89 plates, gj-in. X 6rf-in.

(Sir Isaac Pitman & Sons. Ltd. Price 20 - net.)

In this book, which is at once remarkable for the value and
beauty of the illustrations, the classification of Dr. Boulenger
has been generally adopted, and from it it is possible to get an
excellent idea of recent reptiles. Various families are con-
sidered and tables are given of the genera, with the number of
species known. Habits are touched upon and some details
are included as to methods of feeding the animals. Besides
the excellent pictures of the complete animals various parts
are illustrated, such as the spurs of the Indian Python, w-hich are
the external portions of the well-formed hind legs possessed by
members of the family Boidae. .Another most striking illus-
tration is of the head of the Pit \'iper la New World
rattlesnake) showing the fangs.

The .Airy Way. — By Geokgi: A. B. Dewar. 253 pages.
7^ -in. X 5-in.
iChatto ^: Windus. Price 6 - net.l
This book is a series of essays, written in Mr. Dewar's well-
known manner, which deal principally with flight ; and such
various creatures as butterflies, birds and bats are discussed
because they are all endowed with wings. There is. however,
much dealing with rural life and natural history, which goes
to make an interesting volume.

NOTICES.

LESSONS IN NATURE STUDY.— A great deal of good
might be done if schools would take advantage of the
specimens of a seasonable character, accompanied by outline
notes, which Mr. J. F. Rayner. of the Botanical Garden and
Laboratory. Highfield, Southampton, is now sending out for
the use of schools and teachers generally.

FORTHCOMING BOOKS.— Messrs. Bailliere, Tindall and
Cox announce that they are publishing immediately the
following books : — " Atlas of First .Aid." by B. Myers ;
"Military Sanitation," by E. B. Knox: "Micro-organisms,"
by M. Herzog.

The English translation of Professor Henri Bergson's most
important work, Creative Evolution, will be published on
March 3rd, by Messrs. Macmillan & Co. The book is
arranged in four chapters, with the following headings : I. The
Evolution of Life — Mechanism and Teleology. II. The
Divergent Directions of the Evolution of Life — Torpor, Intelli-
gence, Instinct. III. On the meaning of Life — the Order of
Nature and the Form of Intelligence. W . The Cinemato-
graphical Mechanism of Thought and the Mechanistic
Illusion — A Glance at the History of Systems — Real.
Becoming, and False Evolutionism. The translator. Dr.
Arthur Mitchell, refers to the help he received through the
friendly interest and assistance of Professor William James,
who. had he lived to see the completion of the English edition.
had intended himself to introduce the work to English readers

in a prefatory note. The author has himself carefully revised
the whole work.

SPECTRCJSCOPIC APPARATUS.— We have received
the revised and enlarged edition of Messrs. .Adam Hilger and
Co.'s general catalogue, in which there are illustrated and
described a large series of spectrometers, spectrographs,
polarimeters, and refractometers. to.gether with the accessories
that are required, and a list isgi\en of the special sensitive plates
mamifactured for spectrographic work by Messrs. Wratten
and Wainwright. .\ sectional list has also been issued by the
same firm, dealing with Echelon diffraction gratings and
Lummer-Gehrcke parallel plates.

.\ NIAV TYPE OF PHtJTOMETER.- Messrs. R. & J. Beck
have brought out an instrument iThcHolophaneLumeterl which
they claiui to be the first made for measuring the intensitv of
light as seen by the e\-e and not emitted from a light source.
It is a small portable instrument, containing an illuminated
disc with an aperture in the centre through which the object
to be examined is looked at. The illumination of the disc is
then adjusted until it is the same as that of the object to be
tested when the brightness of the latter can be immediatelv
read oft" on a scale of candle-feet. There are man)- uses to
which such a photometer may be put — for instance, it can
be used to ascertain whether the light on a book is sufficient
to read by without straining the eyes.

Knowledofe.

With which is incorporated Hardwicke's Science Gossip, and the lUustrated Scientific News.

A Monthly Record of Science.

Conducted by \\"ilfred Mark Wel.b. F.L.S., and E. S. Grew, M,A.

APRIL, 1 y 1 1 .

SOIL BACTERIA AND CROP PRODUCTION.

Bv H. B. HUTCHINSON. D.Sc.

During the last thirty years the methods of
estimating soil fertility have undergone considerable
change. The crude chemical method of determining
total soil constituents has given place to one more
nearly appro.ximating that of the plant itself, and the
value of the results so
obtained has been con-
siderabh' enhanced by
the consideration of
the mechanical com-
position of any given
soil.

Within the same
period the old concep-
tion of the soil as being
merely a store - house
of plant food has given
way and soil is now-
regarded rather as a
medium in w h i c h
myriads of micro-
organisms e.xist and
e.xert their influence.
The dissolution of
plant and animal re-
mains and the con-
sequent production of
substances capable of
subserving plant gro^\■th
bacteria. Smce nitrogen i
soil constituent, it is not

Figure 1.

Wheat Growing in Partially-sterilized Soils.

Left to Right: Untreated, Tolnened. and Heated Soil.

is the work of soil

is the most valual)lc

surprising that thi'

organisms responsible for various reduction anti
oxidation changes such as amiuonilication. nitri-
fication, nitrogen-fixation, and so on. have received
most attention, while those inducing cellulose fenuen-
tation and changes in sulphur and iron cornpounds
have been less studied.

Although the activities of this micro-flora result
in the production of plant food, it would be fallacious
to assume that this represents in any adequate
measure the total changes occurring in the soil.
Decomposition of highly-organised nitrogenous

bodies mav be accom-
plished, nitrates formed,
-_. and nitrogen iua\- be
fixed, but a portion of
this elaborated material
may be lost again by
the action of other
organisms. S\-mbio-
sis and antagonism
between soil organisms
have been obser\-ed in
man\- instances, and
recent investiga-
tions indicate in a
striking manner the
far-reaching effect of
another factor inimical
to bacterial growth.

The extent to w hich
this factor exerts an
influence is shown by
results obtained from
experiments on the
partial sterilisation of soils. Numerous workers
ha\-e shown that if a soil is subjected to the action
I if lu-at or of mild antiseptics, an increase in the
fertilit\- of that soil ensues. In the former case high
temperatures (95" to 100° C.) were adopted, and no
doubt led to a certain amount of chemical decom-
position of some of the soil constituents. Direct
chemical action, however, is insufficient to account
for the increase in fertilitv.

123

124

KNOWLEDGE.

Aprh-, 1911.

The use of volatile antiseptics seems to have been
first introduced by Oberlin for the destruction of the
phylloxera disease of the \-ine. The fa\-ourable
results obtained bv the use of carbon disulphide led
to trials with other crops \\ itli equally good results.
()b\ioush-. the benefit could not be due to any
diminution of plant diseases, Init to a stimulation of
processes concerned in the nutrition of the plant, or
of those occurring in the soil itself. Koch regarded
this increased fertility as being due to a stimulation

\'arious crops were grown in these soils — buckwheat.
r\-e, mustard and wheat — and the results obtainetl
with r\e ma\- be taken as tx'iiical. Table .\ gives
various data as to the weights produced, while
Figure 1 is from a photograph of some young wheat
plants growing in the respective soils.

The use of partially sterilised soils for plant
experiments has two distinct effects: there occurs a
striking increase in the weight of crop, varying from
twent\' to over two hundreil per cent. and. further,

Soil.

Weight of
Green Crup.

Weiijht of Div Maitcr.

Percentage Composition of Dry Matter.

In Grams.

Relative Wei{;hts.

N.

1'2 O,

K, O.

Untreated ...

Heated

Tdliiened ...

10J-')5
162 -10
120-07

J7-14
59 • 30
44-76

100
160
120

- 698

1-147

-742

•59
-64

-54

1-05
l-2cS
1-01

Table A.

of the plant hv small (]uaiitities of the antiseptic
remaining behind in the soil after treatment, while
Hiltner and Stormer attributed it to the destruction
of nitrate-decomposing bacteria, and to a subsequent
growth of humus decomposers — the various species
of Stre[)tothrix. Further it was sujiposed to be due
in part to an increased growth of those bacteria
which produce nitrates or assimilate atmospheric
nitrogen.

For some time this problem has been studied b}'

there is almost invariabh' an increase in the nitrogen
content of such cro()s. Other experiments have shown
tliat the latter is due to an assimilation of nitrogen as
ammonia instead of as nitrates as is normally the case;
mild antiseptics and moderate heat are sufficient
to destroy the nitrifying organism. In order to
follow the various chemical and bacterial changes,
samples of the respective soils were stored in
sterilised bottles and analvsed at certain intervals.
Chemical analyses revealed the fact that a rapid

Trealnienl of Soil.

Total Nitrogen as Ammonia and Nitrate.
I'arls of Nitrogen per Million.

Bacteria per Gram of Soil.
In Millions.

At Ijeginning.

After 23 Days.

Gain.

At beginning.

After 25 D.ays.

Gain.

Untreated IJ-.S 17-7

Heated (98^ C.) 19-5 55-8

ToUiencd 17-0 J9-S

1 1

3-9
36-3
22 -S

6-76

-000007
2-84

9-81

5-23

40-62

3-05

5 - 23

37-78

TAIU.E B.

Dr. E.J. Kussell and the Author, and the probahilit)-
of the existence of an altogether different factor has
been indicated. Our initial experiments were
designed to show the actual increase in fertility as
measured 1)\- plant growth. Samples of soil were
carefulK' sie\ed and filled into glazed pots, which
were then di\ided into three sets. One set remained
untreated, a second set was heated to 100" C. for
three hours, while a third was partially sterilised by
the addition of four per cent, toluene and afterwards
freed from this substance by exposure to the air.

decomposition of the nitrogenous constituents of the
treated boils, witii amnicniia ]iroduction. was taking
place, while the untreated soil slowl_\- produced
nitrates. Bacteriological anah'ses demonstrated an
initial drop in the number of organisms present, with
a subsequent rapid increase, until at the end of a few
weeks the tolueiied soils contained ii\e to eight times
the number of bacteria as the untreated soils. Thi'se
changes are shown in Table I!.

The connection between bacterial activity and the
production ot [ihiiit food is obvious from the above

April. 1911.

KNOWLEDGE.

125

results, and the assumption that increased fertiHt\'
was due to a bacterial rather than a chemical cause,
appeared justified. Such being the case, a closer
study of the bacterial flora of the various soils was
undertaken and an attempt
was made to account for the
enormously increased num-
bers. Definite quantities of
the soils were introduced into
solutions containing peptone,
urea. ha\-dust. and so on, and
the amount of ammonia pro-
duced after certain intervals
was estimated. In almost ever\-
case it was found that the
cultures containing toluened
soil were more capable of
decomposing the substances
supplied. This result could
be induced ui i bv a greater
virulence of the toluened soil
bacteria, or (hj the presence
of some inhibiting factor in
the untreated soil. Experi-
ments where toluened soil
was inoculated with bacteria
from untreated soil gave,
however, a more vigorous
decomposition, and a higher bacterial content than
a toluened soil alone, thus showing the superioritv
of normal soil bacteria over those persisting after

Figure 2.
Gelatine Plates showing relative numbers of Bacteria

in Untreated. Toluened. and Heated Soils.
Bottom. Left-Hand: Untreated Soil. Top: Heated

Soil. Bottom, Right-Hand : Toluened Soil.

When, for instance, toluened soil was mixed with
five per cent, of untreated soil there ensued an initial
increase in bacterial growth and arn:"c -lia production,
but these changes were retarded ir. :h; course of a
few weeks. (Sji Table C.)

It is apparent from the
above, that, while consider-
able bacterial growth has pro-
ceeded in three out of the
five soils, it has remained
stationary in the untreated
soil and toluened soil with
five per cent, untreated soil.
This condition, however, onlv
begins to be evident some
weeks after the beginning
of the experiment. In fact,
during the period up to the
thirtv-eighth day. the toluened
soil receiving untreated soil
possessed the highest bacterial
content. In brief, the limiting
factor appeared to be of a
biological nature, possessing
the following properties : —
{a) destroyed by heat and
volatile antiseptics, (b) in-
capable of passing through
filter paper, (c) contained in small quantities of soil.
((/) cajiable of growth, and of reducing the numbers
of bacteria. It appeared to exert a limiting effect either

Treatment of Soil.

Bacteria per gram of Soil.

Total Gain in Nitrogen

as .Ammonia and
Nitrates after 57 D.-iys.

After 38 Days.

After 6r Days.

Gain.

1. — Untreated Soil ...

7.500,000

9,500,000

2,000,000

2-5

2. — Toluened Soil

31.800.000

60.100,000

28,300,000

24-3

J. — Toluened Soil + sterilised extract of
untreated Soil

31.600,000

67.000,000

35,600,000

23-4

4. — Toluened Soil + non-sterilised cxtr ict
of untreated Soil

45.200,000

166,600,000

141.400,000

43-7

, 5. — Toluened Soil -|- 5% untreated Soil ...

1

46,900,000

48,000,000

1,100,000

20-3

T.\BLE C.

treatment with the antiseptic. This point having
been cleared, it became necessarv to search for
a limiting factor in normal soils. It was not
possible to demonstrate the presence of injurious
bacteria nor that of any toxic body. On the contrary,
an extract from untreated soil, that is, liable to
contain any soluble toxin or toxic organisms,
produced a vigorous decomposition, but similar
experiments where toluened soil was inoculated
with small quantities of untreated soil, showed the
limiting factor to be transmissible in soil itself.

by competition for nitrogenous foodstuffs, or by des-
tro\ing the bacteria in the soil. .\ search was then
made for organisms larger than bacteria, and. by the aid
of special media, protozoa were found in the untreated,
but not in the treated soils. The influence of soil pro-
tozoa upon bacterial change was demonstrated by
adding cultures of these organisms to flasks containing
extracts of untreated and toluened soils and peptone
solution, and estimating the amount of ammonia pro-
duced after a given period. In this manner we were
able to depress the acti\it\' of the toluened soil bacteria

126

KNOWLEDGE.

April. \9\\.

to a point ht-low that of thu untn-'atcd
Many different species of soil proto;^o

lieen isolatecj. chief amonj;

which ma\- be mentioned

P 1 e u r o t r i c h a . C o 1 p o d a .

\'orticelhds. Amoebae, and

Monads. A large number of

soils ha\-e been examined,

and these organisms would

appear to be of uni\ersal

occurrence : tlu ir nuniber

varies \\ith different soils.

and at different de[iths of

the same soil.

A study of their beha\'iour

towards \'arious ph}'sical

and chemical agents has sug-
gested fresh lines for investi-
gation in connection \\itli

soil tcrtilit}-. Experiments

ha\e shown the thermal

death-point of protozoa to

lie between 4J" and 4<S" f.

and it has been found that if

a soil be heated to 50" C.

instead of fOO" C, as for-
merly, a change occurs

similar to that i>roduced b\

toluene. The relatit)ns of

protozoa to intense col<l

or thorough desiccation are

still being in\-estigated. It

is commonh- belie\'ed b\

practical agriculturists that

a sharp hard frost conduces

to increased crop j)roduction

soil bacteria,
a have alread\-

Figure J.

■ri)iii a Plmtii-Micrograph I Plcinutricha, one of the
Protozoa occurring in Soil I.

and in the light of the aboN'e results it would appear
to lie justilied. as extreme cold for a short period

is sufficient to kill main'
protozoa. The Indian prac-
tice of cultiwating and
pulverising the soil during
the hot tlr\- season would
appear to rest upon a similar
foundation.

In this countr\- where
extremes of cold, heat, or
dryness scarcely ever prevail
for any considerable period,
any effectual method of
partially sterilising the soil
would necessitate the use of
cheap antiseptics or the
ajiplication of tempera-
tures easily obtained in
market gardens and glass
houses.

\Miate\'er success mav be
gained in the adoption of
the methods of partial
sterilisation on a large scale,
it becomes evident from the
above results, that a fresli
factor must be recognised in
the estimation of soil fertilit\-.
In the meantime much work
remains to be done in the
study of the relations ex-
isting between bacteria and
protozoa and the conditions

govermn£
the soil.

tht

.rrowth m

M I'Ti: oRK" A,S r KOXOM \-

1!\- W. I-. DENNING, F.R.A.S.

Tm. claims of meteoric astronomy as an attractive field of
ohscrvation, and as a subject of investigation likely to expand
our l<no\vledge, are great — yet it must be cunfesscd tliat it is
not studied as it should be.

A large amount of useful worl< was accomplished by the
British Association Committee on luminous meteors, between
1848 and fSSO, and certain individuals ha\c contributed a
considerable amount of data to this department, but much more
remains to be done. The southern skv is still practically
unexplored.

Meteors not only iieiineate our solar system but probably
circulate far outside that and may indeed pervade tlie whole
universe of stars. If the latter are suns with planetary
satellites then fragmentary atoms probablv abound, some
in the form of cometary swarms, others in more tenuous
streams. In fact, \vhere\cr iilanelary systt'Uis exist we
may take it that meteoric particles, forming as it were
the dusi of such systems, are also puscnl in con-
siderable numbers. And across the wide ami incompre-
hensible .abyss separating one sun from another nu'teors mav
roam in hyperbolic or p.arabolic orbits. The lar-reaching
rel.ations of these objects, their vast numbc i>, ,uid conietarv

associations rende.- them of extreme interest and importance.
We must learn more' of the phenomena which they present in
our terrestrial skies, so that we may judge of their character
and behaviour in the remoter regions of space.

For the present it seems that the photography of meteors
has failed to supply us with an effective and accurate means
of recording their flights on ordinary nights of the year. We
must continue therefore to follow the old and rough method of
registering paths and determining radiants. When we con-
sider. howe\er, that radiation forms an area not a point, and
that eye-estimates of the directions of flight may, after
sufficient practice, be made with a precision almost equal to
photographic trials, the latter has really only a slight advantage.

The chief periodical showers of the j-ear have been watched
for many years, and a large amount of e\idence concerning
their displays has been accumulated. Still the materials
existing are far from being of the character or extent recpiircd.
We w.int nirire data as regards the long duration of showers
.ind as to their stationary or shifting positions of radiation.
The r.idiant points of the principal streams should be
determined on ten or more nights near the date of maxi-
nnnn in cases where the showers are active so long as that.

RECENT INVESTIGATIONS ON AURORA

BOREALIS.

By OUK r.KRLIX CORRESPONDENT.

According to a hypothesis suggested by Professor hypothesis. He also worked out a new inetiiod of

Birkeland of Christiana University, auroras are due aurora investigation bv photographic records,
to cathode rays given out from the sun, and which In view of the inadequate luminous intensity and

on their way through the cosmic space would great mobility of auroras, it had so far been cOn-

converge towards the magnetic poles of the earth, sidered impossible to fix the phenomenon photo-

FlGURE 1.

Figure _'.

The Aurora Borealis.

thus producing a bright fluorescence in the
surrounding air.

In fact, when arranging below a Crooke's bulb a
ver\' strong magnet, the cathode ra\s are seen to
converge towards this, like light ravs converging
towards the focus of a lens. This phenomenon
Professor Birkeland denotes bv the name of " suction
effect" of the magnetic pole.

\\'hen a discharge bulb with a minute "magnetic
earth " suspended in its interior is lined with a
layer of platinum-barium c\anide. any spot struck
by the cathode ravs becomes distincth' visible.

By varying this experiment, there are obtained
the most manifold fluorescent forms reminding in all
details of auroras. In order to test his theory,
Birkeland also undertook three vo\ages of discover\-
to polar regions, from which he brought home man\-
valuable data on the aurora borealis and the
concomitant magnetic disturbances.

His colleague, Prof essor CarlStormer.of Christiana,
in a memoir recently submitted to the Fourth
International Congress of Mathematicians, then
established a theor}- of the phenomenon, showing all
its details to be perfectly accounted for on the above

graphicallv. Professor Stormer, however, realized
that bv choosing a proper combination of objectives
and photographic plates, sufficient sensitiveness
could be insured. B\- means of a cinematographic
objective one inch in diameter and two inches in
focal distance and violet-labelled Lumiere plates, he
then succeeded, on a voyage to Bossekop (Finmarken),
in Februarv and March 1910. in obtaining four
hundred satisfactorv aurora photographs out of a
total of eight hundred, with exposures var\-ing
between a fraction of a second and twenty
seconds, according to the luminous intensity of
the phenomenon.

One of the most valuable uses these photographs
can be put to, is measuring the altitude of auroras
and ascertaining their accurate position in the cosmic
space. To this effect the position of the aurora in
regard to the surrounding stars should be compared
on two photographs taken simultaneously from two
stations connected by telephone. A systematical
application of this method (a report on which was
recenth- presented to the French Academy of
Sciences) will doubtless gi\-e the most \-aluable
results.

127

SCIENCE IN EVERY-DAY LIFE.

]?v Rev. H. N. HUTCHINSON, B.A„ I'.G.S., F.Z.S.

In the opinion of the present writer, one of the
first things to be done by women of the upjier
and middle classes, is to abolisli the pri\ate
kitchen. Such a [ilan would sa\'e space in the
house: a sittint^-room for domestics is hi^hl\-
desirable, and the kitchen could be ma(k- nito
such a room. It would save a \'ast amount of
trouble. anxiet\" and worry. In every street there
should be a large kitchen and confectioner's shop.
The lad\' of the house could, each da\'. order her
meals bv telephone, and the food could be sent out
in wooden boxes for each meal, just as dinners and
suppers are ])rovided b\- the college kitchens of
Oxford or Cambridge. The w riter has advocated this
plan for thirt\- \'ears: but the habits of a nation are
not easih- changed. The waste in\-olved in private
kitchens is enormous. Food would be of the best
under this plan, and it would afford a much greater
range of choice. Companies could be started to
suppl\- this great want, and contracts might be
made quarterh" or yearh". Let the ladies seriously
consider this proposal, for it is certainly within their
power to devise wa\'s of carr\'ing it out.

The danger of fire is considerable, and yet few
householders take an\- [irecautions to diminish the
risk. There is no need to go to an\' great expense; for
hand fire extinguishers can now be obtained at
reasonable prices. Two or three fire-buckets might
be placed on a landin;;. A Ik ise-pi])i.' from the bath-
room might be etf"ecti\e at the beginning of a fire.
In tall London houses, a good ])lan is to pro\ide one
of the top bedrooms with a long rope, so that the
inmates could let themselves down to tlie ground.
.\ stout hook should be fixed just abo\e the window.

Young people are inclined to be careless al)Out
their clothing, and in this matter parents should see
to it that their sons and daughters do not risk their
lives bv wearing thin garments in the spring time,
or in the cool evenings of Ma\- and June. By such
simple precautions much lung disease, rlicuniatism.
and so on, might be axoideii. It neeti hartih' be
said that certain fashions, i.e.. high-heeled boots, are
scientifically wrong and absurd. But probably no
considerations of this kind \vill have the slightest
influence in modif\'ing a foolish fashion, unolving
serious danger to the human bodw We therefore
pass on to the subject of " air." People talk much
about ventilation, especialK- in public rooms and
places of entertainment, but at the same time such
people often pay little attention to the \'entilation of
their houses or flats, or it may be lodgings. In all
our big towns thousands of people live much of their
lives in stuffy little rooms, where they cannot possiblv
get all the air they need to keep in health and
to digest their food. Of late }ears there has
been marked improvement in tliis matter, owing

to the greater use of electricitx' for lighting pur-
poses. But one still sees many rooms (often
of but small size) lighted bv gas. Now this is
really a grave e\il. and the cause of an immense
amount of ill-health and suffering. Those who
li\e in such rooms are simph' breathing poisoned
air, all the time that the gas is burning ! What it
means those who have learned a little chemistry can
readilv comprehend. Lach gas-burner is pouring
into the room a constant stream of carbonic acid
and sulphur dioxide, two poisonous gases. Fortu-
nately a little air enters from under the door, drawn
liy the heat of the fire, otherwise the inmates of the
room would be suffocated. Such a use of gas ought
to be strictly forbidden. B\' a sim[)le plan, which
the writer has often advocated, this gra\e evil can be
a\'oided. An\- plumber or builder could easilv devise
a method of drawing away all gaseous products of
decomposition. One plan would be to have the
lights in the ceiling, but enclosed, as is often
seen in railwa\' carriages. Another wa\' would be
to provide a fairl\- large glass or metal funnel to
hang o\er each gas bracket — to the top of this funnel
a pipe could be fixed of sufficient diameter to take
away all the foul air, either into the chimney or
through a hole in the ^\■all. Central chandeliers might
b:- taken awa\' altogether, and their place supplied by
the Ceiling light, as described aboN'e. A third
de\ ice wiuihl be small brackets on the walls, each
enclosed m an artistic glass case, with pipes to
conduct the bad air to the chimnex'. or through the
walls to the outside. In this simple manner the au^
of our rooms might be kept just as pure and
h\sh as in cases where electricity is the light-
ing agent. Xo matches need be used, for ever\-
biu'iier woidd be [Provided with a b\'-pass, for
lighting and tor turning down, and, of course, incan-
descent mantles should be adopted on account ot
the increased light the\- afford. Builders of small
houses shoukl be compelled b\" law to provide for
some such plan. or. at least, gas-fitters should be
forbidden to fit gas-burners in such a way that the
products of combustion cannot be led away from the
rooms. If householders would adopt this sim[)Ie
plan the\ would not only get their rooms lighted
cheaplw but the\- would help to make it more largely
used, and so. before long, obtain a considerable reduc-
tion in the price thereof; also explosions would be
almost impossible.

With regard to the heating of houses we are
workiuij on wrong lines. The usual method is
unsatisfactorx in every sense {except artistically) and
quite unscientific. So here is a matter in which
teforin is greath' needed. The use of coal in fire-
places not onl\- cau.ses smoke with all its grave evils.

but iinohx's a waste that is truK piodigious

W(

U.s

APRir.. 1911.

KNOWLEDGE.

129

must consider not onl\' the uaste of useful carbon
and so of heat — that is bad enough, especially in its
indirect results — but we have to consider the loss of
those extremely valuable bye-products that might be
obtained if the same fuel were heated in retorts and
made to yield up its gas. The wealth of England
is partlv due to its splendid coal-fields. Coal being
part of the national wealth, it should be the aim of
all good citizens to prevent the waste of it. But as
things are we allow a large part of our wealth to
escape up the chimney. This is bad science and
worse political economy ; it means we are spending
capital as well as income : but unless the women will
approach the subject in a different spirit there is not
much prospect of reform.

To make the matter clear, it will be necessar\' to
explain very briefly what happens in the manufacture
of coal-gas. Coal is heated in closed vessels called
retorts and the gases driven off led awa\- into
gasometers, and thence to the mains that supply our
houses. Now the three chief residual products of
this process are : coke, an ammoniacal liquor, and
coal-tar. The coke is principally used in manu-
factures : its value depends on the kind of coal from
which it is got : some kinds yield a coke of great
value commerciallv, the gas companies deriving a
large income from its sale. To some slight extent it
is used in domestic grates, especialK" in kitchen
ranges. But the second product. amiu(.)niacal liquor,
is still more important. .\ ton of cannel coal will
}-ield eighteen to twenty pounds of ammonia un the
form of sulphate), ordinar\- coal \-ields about sixteen
pounds. The chief use of the sulphate of ammonia
is as a fertiliser of soils, and for this purjiosc it
realizes good prices. The third b\e-product is tar
liquor. This substance yields, by distillation, a wide
range of products of great and increasing industrial
value. In the process some highh- volatile pro-
ducts are given off — consisting principalh- of benzol
and afterwards a large amount of light nil called
" naphtha " (a mixture of h\-dro-carbons). .\t this
point the residue in the retort is callei.1 " arti-
ficial asphalte," and as such has a commercial
value. But if the heat is forced and distilla-
tion continued a large amount of hea\y oil is
obtained, and the mass left in the still is hard pitch.
The heav\- oils are a mixture of naphthalin. phenol
(carbolic acid), cresol (cresylic acid), and anthracene
and so on. The benzol obtained in the first stage of
distillation is the basis of aniline and its warious d\es.
Naphtha is used as a sohent and in other wa\'s.
Carbolic acid is largely used as a disinfectant and
also is the basis of many valuable dyes. Anthracene
is the basis of a very valuable dye called " artificial
alizarin "" and most of the abo\e substances have
other applications of minor importance. The
following figures, kindly supplied by the secretar\-
of the Gas Light and Coke Company, mav be quoted
here. For the year ending June 30th, 1910. this
company purchased coal to the \alue of £1.052.000.
The revenue from coke was £"536,000. Sulphate of
ammonia and cyanogen products vielded £1X4.000.

From the latter are obtained sodium cvanide, largely-
used in gold mining, Prussian h\jz, and so on, used
for other chemical processes. Ti.i ether bye-products
e.g., tar, pitch, creosote, benzol :.nd anthracene
brought in a revenue of £"95,000. I': v.jll thus be
seen that the total revenue from bye-products
amounted to the large sum of £"815,000; i.e., over
three-quarters of the value of the coal usovi.

The abo\e \er\- brief account suffices to prove that
several inqiortant industries depend upon gas-making.
Consequently the more gas is used for " domestic "
heating, cooking and lighting, as well as providing
motive-power by working gas engines, the more men
and women will find employment in these industries,
thus at the same time earning a li\ing h)r themselves,
and increasing the natural wealth of the country.

In the last ten years or more, enormous improve-
ments have been made in the domestic fire grate : it is
now not only more artistic, but much more effective
ami economical, and thus a further step has been
gained in diminishing smoke production in large
towns. Many attempts have been made to construct
a smokeless domestic grate, but this is almost
impossible ; for when once the hea\'\- carbonaceous
smoke has been produced, it is ver\' difficult to burn
away the carbon particles completely, on account of
the large volume of nitrogen present with the oxs'gen
in the air passing up the chimney. Sn that the
best method ot preventing smoke is to jiiit on the
coal in \er\' small (]uantitii-'S. Another good [)lan is
to liurn wood or coke with the coal. The use of
anthracite coal would result in a smokeless and very
hot combustion, but it is difficult to light and also
requires a special stove. Consequently the initial
cost largeh- stands in the way of the general use of
anthracite for domestic use, and also it is obvious
that any great demand for such coal would create so
great a rise in prices as to render its use prohibitive,
the suppl\- being limited. The use of half-baked
coal is not a new idea, but since " Coalite "" was put
on the market attention has once more been turned
to this method. The "Coalite"' process has one
ad\-antage, viz.. that tlie fuel is of greater unifortuitw
and the A'ield of tar is doubled, instead of being
decreased. In the opinion of a leading chemist,
" Coalite "" will be the ideal fuel for home use, but to
the present writer it seems that the onh' satisfactory
solution of the problem lies in the abolition of coal-
fires, their place to be taken chiell\' by gas-fires and
gas-stoves. This is. undoubtedly, the proper scientific
w'a\' of solving the smoke problem, and of preventing
the waste of precious coal. Not that it is the only
solution, for in larger houses, hotels, public buildings,
colleges, and such places, hot water heating is almost
a necessity. The furnace in those cases might be
constructed to use gas instead of coal. Electric
radiators might with ad\'antage be used in small
rooms, and for warming odd corners. At present,
however, they are expensive. For some years past,
as all Londoners thankfulh- recognise, London fogs
ha\'e been much fewer and tar less dense than was
formerly the case, and it is generally recognised that

130

KNOWLEDGE.

April, 1911.

this welcome improvement is chicll}' due to the more
general use of gas-stoves and gas-fires. Having used
gas-stoves forjnanv \"ears. the writer has no hesita-
tion in recommending them. If properly fixed up
b\- a competent fitter, there is an entire absence of
smell in the room. At the back is a tfue-pipe to
carry a\\a\- the gaseous products of combustion.
This should be fairly long — say. three feet at least —
and carefulh- fixed on the stove in such a way as to
avoid any leaky joints. Tliis is most imj)ortant. It
is best to fill up all the space between the stove
and the surrounding fireplace. Ladies appear to
have a prejudice against the gas-sto\-e. which is a
pit\-. The\' must, however, admit that an immense
amount of labour is sa\'ed In- their use, and that
dust is entirely a\'oided. There is this further
advantage (especiallv in bedrooms), that a gas-
stove can be regulated to a nicet\'. and turned off
when no longer required.

Professor N'ivian 15. Lewes, lecturing on Decem-
ber 8th of last \ear before the Ro\-al Institution,
said : "' The principal cause of the cloud which
hangs over our big towns, cutting off the direct
ra\'S of the sun and ruining health, \'aries with
the localitw In the South of England it is
the domestic grate, using bituminous fuel, which
is responsible for the major portion of this pollution
of the atmosphere ; whilst further north, in the
great manufacturing centres, it is the factory shafts
which emit the \y<i\\ of black smoke that aids in
shortening life and killing vegetation, and which
begrimes and finalb' helps to destro\' our public
buildings." "

One fre(juentl\- hears London ladies complaining
of the dust and dirt that blackens windows, ceilings,
pictures, hangings, clothes, and so on, l?ut it is in
their own hands that the remed\' lies. Let them
abolish coal-fires !

SOL.AR nisriRIlANCES Dl'RlXC !• F.l'.Rr.XRV, 191 1.

r.v FKAXK c. dexxi-:tt.

.Although meteorological conditions ha\e boon very nn-
favourable daring February, it has been possible to obtain a
fairly regular record. Somewhat greater activity has been
noted. The surface appeared to be quite free from disturbance
upon February 2nd, 3rd and 25th, and none was seen on the
Sth and 23rd. Only faculae were visible on the 1st. 22nd and
24th. On February the 1st, at noon, the longitude of the
Central Meridian was 246' 18'.

No. 2. — First seen on February the 10th as a fair-sized spot
a few degrees from the eastern limb, solitarv. with faculae
around, but mostly to the east. Upon the 11th ami 12th it
contained three or four umbrae : the diameter was 14.000 miles.
From the 13th until the 15th the spot seemed shrinldng. and
its umbra crossed by a bridge, with three tiny pores close
north to east on the 14 — 15th. The dwindling spotlet was last
seen as a pore on the 20th.

No 2a. — .\ pore amid the faculae about 52.000 miles to the
rear of No. 2 upon the 11th. Three or four pores upon the 12th,
and next day a curve of pores like part of an elliptical ring, and
containing one of a larger size. On the 14th. this group
presented a somewhat peculiar appearance — a double umbra
partly surrounded by pcninnbra. and further east, a group of
umbrae almost like a capital F, and two or three pores. On
the 15th the rear spot was 9,000 miles in diameter, with a
bridged miibra and a curve of pores from east to south, whilst
ahead four pores outlined the form of a lozenge, and three

others remained to the north-east. On the 17th the spot had
shrunken to a pore, whilst larger spotlets had developed ahead ;
making the total length about 66,000 miles. Only one or two
pores continued until the 19th and 20th, when last seen. The
group was close to the faculic area C. in the chart for January.

No. 3. — On the 11th a group of pores 40,000 miles in length.
A double pore acted as leader, having three tiny pores forming
a triangle in the rear. On the 12th two pores only, in a faculic
setting, which formed pretty curves. Not seen again. It was
closely south-east of the place of No 1.

No. 4. — .At 9.30 a.m. on the 20th two pores were easily seen
and measured, both on longitude 7 , and some 11,000 miles
apart. By 2 p.m. both had disappeared.

No. 5. — -A single spot amid faculae. first seen near the
eastern limb on the 26th. On the 2Sth there were two spots,
and a few pores. The western spot contained four umbrae
on March 1st, and during the day pores began showing farther
east; on the 2nd the length of the outbreak was 57,000 miles.
Only a few pores remained on the 5th, when last seen, but
faculic disturbances marked the area as it drew near the limb
on Sth and 9th,

On the 24th, on the south-western limb, in latitude 36^,
there was a splendid prominence form some 110,000 miles in
height.

The chart is cimstructed from the observations of Messrs.
J. McHarg. A. A. Kuss, E. E. Peacock, and the writer.

D.w OF ff:bruary.

ii 1£

17 , 1^ ,?■ . It- . 1^, |^ . 1.1 . ip ?

7 f •; f 3

y ^6 ^5 ^4 2,5 22 21 1,0

B

oW

N.

0 10 ZO 30 40 50 60 70

90 100 110 120 130 140 150 160 170

190 200 30 220 230 2M 250 260 270

290 300 310 J20 m HO 350 360

■■■ Sec .Xtttiiir, \ol. .S5, page 290. December 2ilth. l')|0.

NOTES UPON THE FUNDAMENTAL SYSTEM

OE STARS.

By F. A. BliLLAMY. Hox. M.A., F.R.A.S.

Owing to the unfortunate dela_v, mentioned in the
last number of " Knowledge," Professor Boss"
arranged second visit to San Luiz, with the other
members of the observing staff, Mr. A. J. Roy, Mr.
Sanford, Mr. Zimmer, Mr. Fair. Mr. Gibble and Mr.
Delavan, and witli the instruments, was postponed to
Januar\-, 1909, b\' which time it was expected tiiat the
observatory buildings would be read\- for the instru-
ments. Among the instruments were the Olcott
meridian-circle, clock, chronographs, photometer, antl
other necessary apparatus. Immediately on arrival
at San Luiz the various instruments were erected, and
preliminary work was started. When the necessary
adjustments were effected the actual programme
of work, carefully arranged at Alban\-, was begun by
the obser\'ers, and will be continued until completion;
the \\hoIe work of observation was then expected to
take about three years from the time of commence-
ment (April, 1909). Professor R. H. Tucker will
be left in entire charge of the obser\att)ry and work.
This astronomer, who is probabh- the most skilled
observer in meridional astronom\-, is the assistant in
charge of the meridian-circle at the Lick Observator}',
and has been granted leave of absence from there
for the express purpose of assisting in this
important investigation. Professor Tucker was an
assistant at the Albany Observatory thirt}- years
ago ; he was also the chief assistant for many
years at the national observatory at Cordoba.
Argentina, later on joining the staff at the Lick
Observatory, where he has been for ten \-ears
engaged in important meridian work. Mr. Rov
and Mr. Varnum are the two senior assistants at
Albany, and are experienced observers with the par-
ticular instrument which is being used at San Luiz ;
moreover, it was thev who largely contributed to
the Albany observations of 1907-8 ; so we mas-
hope for excellent and homogeneous results.

Owing to the extreineh' dr\- climate of San Luiz,
the vegetation is scanty, except in places where resort
is had to irrigation. The plot upon which the
observatory stands is under irrigation and is covered
with a luxuriant growth of nlfalfa^ : the effect of this
is of great importance, as it protects the soil and
reduces the variations of radiation to a minimum, a
most essential point to be considered in astronomical
observations at low altitudes. The soil, under the
rich surface la}'er of vegetable mould, is a sandy
loam from three to five feet in thickness: under this is

a layer of gravel of similar thickness, and below that
a dry and hardened chn- : this is considered to offer
an ideal foundation for the piers of a meridian-circle.
Within a week the true meridian was settled, plans
were made ft)r foundations, and the site was soon
covered with bricks and mortar. The transit room,
22-ft. X 23-ft., is of brick, with a wooden roof; the
office rooms, of one story, are of brickwith agalvanized
iron roof ; the exterior dimensions are about SO-ft. by
60-ft., the central portion being arranged on the usual
Spanish method with an interior court, or patio. The
first stone was laid on October 5th, with a little
ceremony, in the presence of officials and friends.

Having gi\-en a brief and general account of the
causes which niaile this great piece of astronomical
work necessary, and Imw it became possible to
accomplish it. we will complete this article b}-
giving a translation, containing more details,
of a paper in Spanish read b\- Professor Tucker,
before the American International Scientific
Congress, held at Buenos Aires, Argentina, printed
at the expense of the Department of Meridional
Astrometr\- of the Carnegie Institution of Washing-
ton. U.S.A. American astronomers are greath'
indebted to the munificent generosity of Mr.
Carnegie for providing the mone\-, without which
this, Pasadena, and other astronomical researches
could not be made, or, at least, could not be carried
ciut so speedih' or eftectix'ely.

The Fundamentai. System of Stars. +

There are two great and permanent problems in
astronom}-. One concerns the positions of the
bodies visible in the Uni\erse. and the other relates
to the form, history, and constitution of those bodies.
Of the second problem, the chemical constitution
and the history of the evolution of the stars, the
sun, planets, nebulae, and comets, are keeping the
great telescopes, the photographic [ilates. and the
spectroscopes, and other instruments well employed
for their investigation : these instruments are of
modern form.

For the first problem the Meridian Circle,
though much older, has until now been the most
perfect and most used instrument, though of less
power, for the determination of the positions of these
bodies. For the regular observations of transits of the
stars, an instrument of this form has been erected
in every case in the great observatories of the world.

This is a species of lucerne.
i El Sistciiui Fmuhjincntnl dc las EstrcUas. para

H. Tucker, Observatorio dc San L\iiz,
F. A. Bellamy.

lylO, June 30th; translated

131

132

KNOWLEDGE.

April, 1911.

The determination of the positions of the stars is
the basis of all that we know of the movements of
the sun. moon, planets, and, in fact, of the earth.

To fix the position of the system of the sun and
our famil\- of planets among the stars it is necessary
to know, with everv exactitude, the positions of the
stars which ser\-e as landmarks or guide posts in our
journev. Not onl\' is it necessar\" to know the
positions now. in the \ear in which we li\e. hut to
compare them w ith the observations of former years
from the earliest times of exact astronomical research.
All the stars move: there is no exception according
to the laws of our science ; the difficuhy is to
distinguish between all these movements and the
proper motion of the solar system. It is necessarv'
to studv the movements in all parts of the sk\-. and
observe many stars in every part, in order to resolve
the problem of tlie movement of the solar system.
There is not a single place on the earth where all
stars ma\- not be observed with the necessary
accurac}'. At one observatory on the equator of our
earth one could observe nearly all the stars ; but here
difficulties would arise owing to the small altitude of
the poles, and one could not make exact obser\'a-
tions under such conditions.

For a complete system of stars it is necessary to
have at least two places for observation, one in the
Northern hemisphere and one in the South. There
will be many stars which it will be possible to observe
in both places, and those observations will serve to
bind or connect the results, and for comparing the
conditions and results of a system which shall include
all the sky. Already man}- thousands of observations
of stars exist in the southern as well as in the northern
sky ; those observations were made in the earh' da\s
when the first obser\-atories were erected in the south.
But errors of various kinds appear in all the observa-
tions. Some are explained by errors of the instrument,
some by errors in the positions of the fundamental
stars, others by the methods used in the calculations,
others by the methods of observation. In general,
these are a class of s\'steniatic errors jieculiar to
an instrument, tf> a star catalogue, or to an epoch:
it is necessary to investigate all their sources.

The observations of the northern sky include
similar kinds of systematic error as well : but the
observations are much older, and there has been
much more time for the study of the errors of method,
and for comparing the results w ith the fundamental
methods in use.

Each time that one empln\s these methods, it is
possible to adjust or correct the observations to the
same epoch, and likewise we are able to improve the
results of the old observations. There is nothing
new in that process ; it has been used at various
times for connecting the results of all observatories
in the world, both in the north and south hemis-
pheres. But, in general, the zone of stars which
can be observed in both hemispheres has served to
adjust or connect the s\stem of the north w ith the
system of the south. It is difficult to extend the
range so as to embrace the positions from this zone.

w ithout deviation, from one pole to the other. Other
difficulties exist and arise when \'arious instruments
are used, and when different methods of observation
and calculation are employed in obtaining the data
used in such a comparison.

Now we have a more complete plan for adjusting
or connecting the observations of both hemisiiheres.
1)\- a fundamental method, and we hope that the
results of this plan will scrNe to impro\e the
positions of the stars in all the sk^■. It will be the
foundation from which to compute new positions
for our epoch, and the base for studying the old
positions.

The Plan.

The plan includes : —

(i7) The obser\'ations, witli one iiis/riiniciit. ot
all the principal stars in the sk\- :

(b) the use of a fundamental method to fix

afresh the positions of those which ser\-e
for the basis of the calculations :

(c) the investigation of the results of all obser-

\ations by a uniform method ;
((/) the comparison with the results of old

observations by the use of these new

positions ;
(c) and the binding together into one system

all observations from pole to pole.

One Instrument T(.) be Used.

This is the plan which forms a part ot the work of
the San Luiz Observatory in .Argentina. It is the
first occasion on which one has used a single instru-
ment for observations of this class of work in both
hemispheres. The observations for this extensive
plan were commenced in the city of Albany, U.S.A..
some years before taking the instrument to San
Luiz. and. after the conclusion of the obser\ation of
the more southern sky, the same instrument will be
mounted, at another time, in its old {>lace (at Albany)
in order to complete the rest of the observations.
The obser\-ations of the south will be made, therefore,
in the middle of those in the north, so far as relates
to the mean epochs. With the results of these
obser\'ations made upon this plan, it will be possible
to correct some of the systematic errors of the old
catalogues : as also to form a new basis for a
complete s\'stem of positions of the principal stars,
and a connecting link for other stars which one may
include in the same system.

With this object, it is necessary to form a plan of
work which will be general and comprehensive,
avoiding, as far as possible, the effects of s\ stematic
errors in the observations and in the calculations.

It is also necessary to study all the errors of the
instrument and apply the proper corrections. Of
these the most important are, the division errors or
graduation of the circles, errors or inequalities in the
form of the axes or pivots of the instrument, and the
flexure of the telescope. There are also the
corrections of the position of the instrument as in
other classes of meridian ojiservations. Besides the.se.

April, 1911.

KNOWLEDGE.

133

it is necessary to investigate tlie personal errors ;
one that depends upon the magnitude of the various
stars, and the other which de[)ends upon the direction
of movement of the stars in the lield of view in the
telescope. These errors are to be studied for e\'ery
one of the observers of the commission.

FUNDAMKNTAL METHOD.

Of great importance is the use of the fundamental
method, in the determination of the meridian line
and for the correction of the astronomical clock.
In the usual method the principal stars have served
for these objects. One used one of the equatorial
stars for determining the correction of the clock,
and two of the circumpolar stars served for fixing the
azimuth of the instrument or direction of the
meridian. But in this simple use of the positions of
the stars the errors of the positions adopted come
into the calculations.

In the fundamental method, however, one does not
adopt the positions of the stars, though they are better
determined. In all there are some systematic errors :
the errors of the obser\-ations. and the proper motions
of the stars, during the years since they w ere revised.
come in.

Each time that there is a new revision it is
probable that the data is more exact. The object of
the revision is to adjust all parts of the area of
positions in such a way that no differences have
entered into the results of the observations when
thev are made in the various regions of the sky,
though it is necessary to use the positions of the
stars in opposite parts. In the measurement of
small arcs there are no great difficulties, tlie errors
are unimportant : but in the fundamental method
it is necessar\- to measure great arcs, even a complete
circumference. In general the errors w ill be greater,
and onl\- by much attention to the observations and
calculations can we avoid the increase of these
indeterminable differences.

This is the first time that the fundamental method
has been employed, to its fullest extent, in a South
American observatory. In the fundamental method
the direction of the meridian will be fixed by the
transits of the same stars made above and below the
pole. In this case the error of position adopted will
have no increasing influence in the computations.

Instrumental Corrections.

The latitude will be determined b\- the same
circumpolar stars. Other stars which come above
and below the pole will serve for a fundamental
determination of refraction. For this purpose the
stars more distant from the pole, which transit at a
small altitude, are selected. It is necessary to study
the refraction at each place, especially when the
observatory is at a considerable altitude above the
level of the sea. For this study we have the com-
bination of the observations at Albany with those at
San Luiz. At one place it will be possible to
observe the stars which pass in the zenith of the
other, and verify, or ascertain, the effects of atmos-

pheric refraction. We use t'le same instrument
with the same circle-division errors, and the tube will
be subjected to the same effects cf flexure when we
measure it in the two places. When we possess the
results of the measures extending from the north to
the south pole in a complete s\'stem, we shall be
certain that the\' will be independent of the
errors of the positions adopted for the stars
(ibserxed. The errors of observations in the zenith
will be minute : and it will be possible to correct
the observations of the circumpolar stars, bv means
of the new refraction, in such a manner that those
w ill be more accurate. Also, we shall have a system
of fundamental stars in all parts of the sk\- for adjust-
ing the various jjarts. These fundamental stars
will be observed in conjunction witli the zenith
and circumpolar stars.

Basis of Right Ascensions.

The elimination of the systematic errors in the
right ascensions is another problem. .^ fundamental
svstem should be based upon the position of the sun,
finalh' : but there is no necessity to observe the
transits of the sun in connection with all the
observations. It is possible to fix the positions of
the stars with that of the sun b}- means of the
oliservations which have been made, and the observa-
tions which mav be made, without adopting the
position of any star whose position is well deter-
mined. Observations of the declination of the sun,
combined with the observations of the stars, in anv
eiioch, will serve to determine the difference of right
ascension of these.

We adopt a system of right ascensions as the
basis and with this proceed to the determination
of the systematic corrections in the various parts.
These corrections have a periodic character ; so that,
when thev occur opposite star groups, with a
difference of tweh'e hours in right ascension, the
sum of the corrections will be almost equal, with
contrary or opposite effect. From this periodic error
the results, when the correction of the clock is
determined by the observations of the stars in two
groups, at an interval of twelve hours, can be freed
of the periodic effect, if mit completeh-. at least in a
great measure.

b"or the change or rate in the correction of the
clock, one uses the stars in the same group each day.
Between the stars of the same group there is little
variation, the positions will be \'ery exact and greatly
improved, but all those of a group can have the same
systematic error.

For verif\'ing the true meridian-line one can
observe by day and by night an electric light, well
fixed in the meridian, as an artificial star at a
distance of one hundred meters to the north. The
position of this light has been determined by observa-
tions of circumpolar stars, and one will pursue
the determinations of this until the end of the work.

For ascertaining the amount of flexure of the tube
of the instrument, one will make observations of the
stars by the two methods, by direct and reflected

134

KNOWLEDGE.

April. 1911.

view, using a trough of mercun- for the reflected
image. The use of this method is of great import-
ance in the drscussion of fundamental observations.
For this class of observations calm nights are
requisite, or those with extremelv little wind.

Old and New Work.

These remarks aim at explaining the reason of the
plan of the fundamental work, the studv of all the
instrumental and personal errors, the determination
of the position of the instrument without using an
adopted position of any star, and the determination
of the correction and the change or rate of the clock's
error by groups of stars in opposite parts of the skv.

This method entails more work, in order to
measure from one star to another, than the method
mostly in use. It is necessarv to continue the
observations at least for thirt\-six hours, in order to
include three groups of stars. The calculations are
very heavv.

The corrections oi the position of the instrument
in a long period ma\- alter sensibh", and it is
necessary to study well the progress of all errors.
The arcs between the stars are large and the errors
of the observations are relativeh' increased. Finallv,
it is necessary to observe in the da\- time when the
brighter stars only are within the limits of vision.

For these reasons, and because one can observe
the small or fainter stars onlv at night, the method
mostl\- used is to fix. by differential means, the
positions of these fainter objects with reference to
the principal stars in their vicinitx".

Inthis manner we have had the principal catalogues.
which have been made by degrees, from one part of
the sky to the other, just as one has fixed the points
on the earth by the difference of longitude between
each point and another point about the first or
primary. All the longitudes have a single base at
last : though all the differences have not been directlv
measured from the base, it is adopted as the origin
of the system of longitudes.

The errors of the differential method can be small
in exact observations, yet they have some systematic
corrections which increase from one epoch to another.

Now and then it is necessar\' to revise the scheme,
compare the fundamental data, and rectify all the
area, with results of great precision and with more
complete calculations. In this way the results of the
old observations are improved, and these then enter
into the modern calculations with less svstematic
error. Astronomers whom we succeed used those
results in the calculations of the movements of the
stars and in the movement of the solar system.

Fundamental Method Extended.

The stars which we observe bv the tundamental
method are now reckoned among those that are better
known or determined in the sky. In the first class
are included the stars used in this method for clock
corrections. The positions of those in the first class.
when once well revised are used for fixing the positions
of the second class, which is of greater extent.

containing the principal stars of all parts of the sky.
A third class, in our plan, includes a great number of
stars, until now of less value in fundamental work,
all well fixed or connected b\ simultaneous observa-
tions. In these classes we shall have altogether
1600 fundamental stars.

By means of the positions of the fundamental stars,
one calculates the positions of all the other stars which
one observes on this plan. We include the greater
part of the stars which have been observed before the
epoch 1S75'0. The positions of these stars serve
to compute man\' proper motions, and for fixing the
direction and quantitv of the motion of the solar
system. We estimate that we shall obser\e on our
plan 15.000 stars in all.

They are of all degrees of brightness from the first
magnitude, besides those more difficult to observe
w ith a telescope of this power. Observations of all
are to be found in the catalogues of the past forty
years and in the older ones. So, as the old catalogues
ser\-e as a basis for the present work, so also will
the observations on our jilan similarh' ser\e for
future calculations.

C"LnL\TE AND WoRK.

The development of this project has given good
results in the observations obtained since the
commencement of our scheme of work. In the first
complete \"ear we have made more than sixtv-two
thousand observations. This number has never been
reached, for this class of observations, by an\' other
observatorw .\s the greater part of the work has
alreadv been concluded, the task will be easier now.

For the most part the climate of San Luiz has
been good. In the first vear we had three hundred
nights during which one could observe for some hours
at least. More than two hundred nights were clear
during all hours. Under the usual condition of the
sky we could generally reckon upon seventy per cent,
of the time for suitable astronomical observations.

A series or c\"cle of fundamental observations is
one-hundred-and-twenty hours, as a general rule, but
the observations are continued without intermission.
One makes six observations successively of a group
of stars and six observations of another group at a
distance of twelve hours from the first. These groups
are usualh" made in the evening and early dawn.
The same observer continues during some hours
at night in order to include the stars which passed
in those hours. Other observers follow during the
last part of the night for fixing other stars with the
principal stars. They are occupied from twelve to
ten and six hours for the observations during the
twentv-four hours.

The commission has consisted of ten persons for
four months only: during the greater part of the
work we had six or eight. W^e are occupied with
the computations as well, but these will require
manv \'ears before being accomplished, and the
results of the preliminarv calculations are sent to
North .America, where the\" will be concluded at the
Alban\- Observatorw

Aprh,, 1911.

KNOWLEDGE.

135

The Erection of the Ohservatokv at
Sax Lriz.

The construction and the installation of the
obser\ator\- has been rapid and without any mis-
fortunes. In September of 1908 we commenced the
construction of the building of the observatory in
the grounds of the State school. The National
Go\ernment gave facilities for acquiring the area
necessarv for the observatory and for a house. Five
months later all was established ready for the
installation of the instruments, and for lodging the
members of the commission.

After the preliminarv examination and the deter-
mination of some instrumental corrections, we
commenced the obser\ations for the scheme in the
month of April, 1909.

It is the first occasion upon which an instrument
of this class has been erected upon artificial stone,
made with Portland cement, grit, sand, or fine gra\-el.
and strengthened with iron.

The two large piers which support the axes
of the instrument are joined into one base extended
two or three meters, and this base, of two meters in

depth, is fixed with the foundaticn, which is extended
beyond the base of the piers ; thersfcre, all is as one
block by this modern method of ccns'cruction. The
height of the pillars, with the b^ise, extends to five
meters above the foundation, which is of sand and
other materials.

There are also two piers of the same construction
for auxiliary instruments in the largi room, and
another pillar at a distance of one hundred meters,
for indicating the meridian mark.

The two astronomical clocks are installed within
a small room constructed for the work rooms ; each
clock is arranged on an artificial pillar of the same
concrete material.

This is the histor}" of the Observatory of San
Luiz. No one here speaks of a work being in pro-
gress; it is an act almost completed.

Up to the present we have verified more than
sevent\"-five thousand observations ; according to
this, five thousand per month since the beginning
of our project.

As all has gone off well until this day, we may hope
that the work will be completed within a year from
the date of 1910. June 30th.

QUERIES AND ANS\VER.S.

Readers arc invited to scud in Questions and to ansK'cr the Queries zi'liicli are printed on tliis page.

(JL'ESTIOXS.

32. THE GENUS LIXARIA.— Is it possible to obtain a
complete list of the species and varieties of the genus Linaria ;

if so where, and at what price ?

G. K. W.

33. "HALLEV'S COMET."— In the March issue of
" Know'Ledge " it is stated that Halley's Comet is still
visible ; and of about the 14th magnitude.

Can any of your readers inform me whether the distance of
the comet from the Sun can be found by calculation at any
particular time, and also whether its speed can be determined ?

As an example, how far will it be from the Sun, and how

man.\- miles will it move a day, two years after passing

perihelion, that is, on April 19th, 1912 ? ,

'^ , , f , Interested.

34. ORIEXTATIOX OF THE GREAT PYRAMID.— In

the articles on " The Great Pyramid " contributed by Proctor
to " Knowledge " Vol. I., he lays great stress on its careful
orientation, and devotes considerable space to the method of
obtaining a true north-and-south line by means of the
descending passage pointing to a Draconis and the ascending
passage equally inclined towards the south ; but he makes no
mention of the means of obtaining a true east-and-west line
which must also have been necessary for the construction,
perhaps because there is nothing to show what method was
actually used. Could a true east-and-west line be laid out by
observing a suitable star near the eastern horizon shortly after
sunset, and the same star near the western horizon shortly
before sunrise ? If so, between what latitudes is this method
available, and what considerations must be taken into account
in selecting a suitable star ? What other methods, astronomical
or otherwise, are likely to have been available to the Pyramid
builders ?

REPLIES.

24. DREAMS. — Much observation leads me to believe that
a large majority, at the very least, of dreams are instantaneous,
occupying only an infinitesimal part of the moment of returning
consciousness from sleep, and that a noise which wakes a

sleeper is itself the cause of the dream which fits it. That,
in fact, the dream is an instantaneous " snap-shot " of a
commingling of subconscious impressions with those due to
external objectives. We must, most of us, be aware how
frequently a mere dozy shutting down of the eyelids is pro-
ductive of a \ery definite panorama of the mind.

While in dreamland I may say that I doubt strongly the
occurrence of the repetition of the same dream in successive
slumbers, except as an exceedingly rare event. I believe that
the dream itself furnishes the thought of the supposed first
dream. Has anyone ever made a note of a dream, and then
referred to it when the repetition is believed to take place ?

L. J.

30. FINDING THE TIME BY THE HEAVENLY
BODIES. — For (II The determination of the time would
depend on the solution of a spherical triangle connecting the
hour angle, i.e., the time, with 5, a and ^, the declination and
altitude of the sun, and the latitude of the place, a being the
angle which has for its tangent the ratio of the lengths of the
stick and its shadow. The result might appear rather complex
to anyone unfamiliar with spherical trigonometry, and some
calculation with trigonometrical tables would be required to
obtain numerical results.

The solutions of (2) and (3) are very simple. (21 requiring no
calculation, and (3) only the determination of a single angle
from the known value of its tangent. Generally if X is the
latitude of any place, and i and 5 the altitude and declination
of the Sun at noon on any date, then 90' — X = ct — 5 is always
true.

For (2) X = 52 ; a -45; therefore 5 = 7°. The dechnation
of the Sun will be very nearly 7' at noon in London on April
7th and September 5th.

For (3) a will be the angle which has for its tangent the
ratio of the length of the stick to the length of its shadow, and
the latitude of the place will be 90'— a + 5.

The declination of the Sun can. of course, be obtained for
any date from the Nautical Almanac ; the sign before S must
be reversed if the Sun has South declination. J. H. G.

FINGER PRINTS: A CHAPTER IN THE HISTORY OF
THEIR USE FOR PERSONAL IDENTIFICATION.

Bv HENRY FAULDS.

The famous Tichborne case gave a great impulse
to the studv of identification as a question in juris-
prudence. I ^\■as leaving this countr\- for Japan in
1873 and the vast crowd around the old Court at
Westminster impressed me greath" with the import-
ance of the subject. Craniologv seemed to man\" to
have had its da}', and the complexities of constantly
varying methods had
induced almost complete
scepticism. If a race
could not be distin-
guished on anatomical
grounds, how could we
ever hope to identify a
single member of the
human family on the
basis of anatomy with
confidence and precision .•'
It had been decreed.
II cm iiic contra dice ut c.
except \'ircho\\ — an
important exception —
that all the soft tissues,
hair, skin, and the like,
were now useless for
such a purpose. I had
studied photographs
most carefulh', but found
them to be traitorous,
the same people l>eing
made to look (]uite
different in a changed
light, by another mode of
developing, with the vary-
ing ps\chological moods
of the sitter. They
were useful but not
precise. .\fter certain
illnesses, too, the living face was fount
as in typhoid fever, and more temporarily m ague.
The tragic effects of small-pox are well known to
novel readers. Our police in England used not long
ago to keep an indexed record of tattoo-marked
persons who had once been convicted. I doubt it
the^• ever had a case like that of a Japanese once
employed by me in their collection. (See plate.)
This man's case was unique, I think, his whole skin

win a tine estate, lUit no one can produce to order
the simplest finger-print pattern in living tissue.
It niav be destroyed, whereas, on the other hand
a complex tattoo pattern can be created but can
hardlv be destroved. It would be quite impossible
by an\- known means to destro}' one like that
now figured. Sir Ed\\ai<l Henry says of finger-

jiatterns that they are
out of all proportion
more numerous than such
measurable features as
tattoo marks, but I think
he cannot have contem-
plated such cases as that
ist described.
Along the great popu-
( lus beach of the Bay
Yedo, where the hos-
pital was which I had
lartre of, were man\-

FiGU

Enlarged Finger Print

to change,

surface being one finelv-w rought pattern, not
intricate but reall\- beautiful. Now such

onh'
case

might be copied, at

trouble and expense, to

others had an almost
unbroken historv coming
down to our own day.
Amid the oldest heaps I
often found fragments
of sun-baked pottery,
on which finger-marks
lad been impressed when
the cla\- was soft. These
seemed to have been
made b\' children, per-
haps 3'oung girls, whose
ancient fingers had
Sweat Pores. dinted the edges of

the soft ware as pie-
moulded b\- the thumb of baker
L. Similar articles were then
(1878) made and sold as to\'S. and I purchased
main- of them in the bazaars of Tokyo. Ancient
ware, baked in the sun but ne\-er fired, and
marked with finger furrows is in high repute for the
ceremonial tea-drinking of Japan, but it is quite
incorrect to sa\', as has been said and written, that
no other is ever used in those depressing festivities.
Sometimes the furrows or ridges of those ancient
linger-marks came out sharp and clear, but much
oftener the\' were blurred or smudged by mo\ement

RE 1.
shouin,

crusts are still
or pastr\'-cook

136

April, 1911.

KNOWLEDGE.

137

c

D

0

during the act of impressing. In the modern
ho\\e\'er, the imprints were better impressed
and were olniouslx intended for ornament.
Had earl\- men some faint knowledge of
the ornamental qualities of hnger-patterns ?
One fancies one can detect some glimmer-
ings of that conception in crude savage
designs, but I must not dilate on that
tempting theme here. Endow ed. or afflicted,
with nnopir e\es I was led very early to
notice how . in the modern ware, one peculiar
pattern of lineations would reappear with
great persistency, as if the same artist had
again left her sign-mark on her work.

I examined directh' many thousands of
lixing fingers, then passed on to consider
impresses on puttw bees - wax, sealing-
wax, clay, and other substances, taken from
ni\' own fingers, those of students under
m\- can.', and medical
men, native and foreign,
and out - patients who
might \'isit the hospital.
These were at first \er\'
roughh' classified and
anah"sed. I am (]uite
sure that at this point
the conception of a wide
and general method of
identification flashed upon
me with suddenness.
Almost immediateh- fol-
lowed a most depressing
sense of moral responsi-
bilit\' and danger. What
if someone were wrongly
identified and made even
to suffer innocenth'
through a defective
method ? It seemed to
me that a great deal had
to be done before publicK-
proposing the adoption
of such a scheme. Till
then we had used wax
and other plastic sub-
stances (and on the
whole paraffin was found
to be best), but now I
remembered lessons on
botany I received in .\nderson's College,
Glasgow, as a lad attending business. The
course — an evening course — cost two shillings
and sixpence for the session. We used to
print the leaves got in Saturday afternoon
excursions with an oily mixture of burnt cork.
Using good printing ink in Japan, then, we
got large numbers of clear and excellent finger
impressions. Their variet\- was wonderful,
and we could study details with much greater
ease and delicacy than in relievo impressions.
From that stage onward I made stead\' obser-
vations, seeking speciallj- to determine whether

Figure 2.

Rugae or ridges on
the under surface
of the prehensile
tail of Atclcs atcr
(Spider Monkey).

^

(g

Y !

toys, [latterns characteristic of one indi\-idual ever varied
from time to time, either in general arrange-
ment or in linear detail. At this time I had
noticed that the pigment in human freckles
and in the skin affection calico. Ic-j.codenna
(supposed by some to be the "white leprosy "
of the Hebrews) migrated, as mv teacher,
Lord Lister, had shown to be the fact with
the pigment on a frog's foot. The mode I
took to test whether the ridges ever shifted
their situation or changed their form was h\
shaving away their elevations or rubbing them
down with various powders to smoothness,
having first taken careful imprints of the pat-
terns. After the skin grew up again fresh im-
prints were taken and compared with the old
ones. These were scrutinised ver\- carefulh-
for changes, but in many hundreds of cases,
tested tlius three or four times, not one soli-
tary exampleof a variation
in pattern was detected.

The patterns always
came up with perfect fidel-
it\- to the old standard.
.\rrangements were made
for a still more extensive
test extending also over a
greaterperiod. but exhaus-
ting illness from climate
and o\erwork caused m\-
return to England, and
broke foratime the thread
of m\- inxestigations. I
returned to Japan after a
rest, but had again to come
back to England in 1886.
The firm con\iction. how -
e\er, was established in
my mind, which nothing
has occurred to change,
that skin furrows for the
purposes of identification
are invariable throughout
adult life. Observations
of select cases from that
period— thirty-two \ears
ago — till now have been
made from time to time
onl}- to confirm m\- early
results. Figure 1 is one
of my earliest prints. In fourteen years it had
not changed in the living person. From time
to time I have watched cases of fever, and ha\e
draw n medical attention to the subject, think-
ing the great activity of the skin shown b\-
peeling ordesquamat ion might be accompanieil
w ith some changes of pattern, but no case has
yet been observed by m\-self or recorded b\-
others so far as known to me. The subject of
classification now presented itself. Those w ho
talk gliblv about comparing a single "' thumb
print " — the favourite digit — with, say. four
millions of single finger prints, do not seem, as a rule.

Figure 3. Skin Lineations (diagrammatic).

Figure 4,

Smudge from
Finger,

th

e

138

KNOWLEDGE.

April, 1911.

to perceive the difficult\'. The supposed numbers of
the Russian armv were often discussed in Japanese
journahsm in the seventies, and it seemed that a
good system should be able to face such numbers.
Five years of earlv life had been spent in learning a
trade — that of Paislev shawl manufacture — which
almost vanished before the end of mv time. It
seemed to have been an utterly wasted time, leading
to nothing and helping no one ; but it had drummed
into m\- dull head how to deal with patterns. What
I intend to con\-ey by a pattern in finger jirints may
best be understood by looking at a few enlarged
diagrams of the central or most characteristic portion
of the riiiiae. or skin-ridges, with their complementarv
furrows or .s///c/, which are found running over the
sole of the foot {planta). the palm of the hand ivola).
and front or palmar surface of the fingers. Indeed,
the\' are e\en found in the prehensile tail of the
spider-monkey, as in the diagram. (See figure 2 —
spider-monkey's tail.) Near the middle of the last
joint of each finger there are usiialh" lineations in the
skin of much complexit\', which form the basis of
identification bv finger prints. (See figure 3).

Without going into details, which would rci]uire a
wealth of illustrative figures and would probabh"
interest but a few, my s\stem proceeds on the con-
ception that an elementary pattern is like a character
in a foreign fount of tvpe. So the classification is
that of a syllabic dictionarv, each s\llable standing
for a single finger-pattern as a Chinese character is
printed in manv dictionaries, and as Japanese is now
printed. Each vow el ma\' be a sxllable in this sense,
but no consonant stands alone, and the vowels
associated with consonants always preserve their
original pattern significance. The consonants go in
related pairs, as t, d : p, b : f , v : s, z : 1, r : m, n ;
k, g. The elements that compose patterns of any
comple.xity are similarly related in pairs, and thus
the association of sound and sense soon becomes
complete in the mind of the dactvlographer. But
the syllable, after all. only denotes a class which
ma}" contain several — usually not a great many —
individuals, all differing in minute details. With
my system the whole strain of the original trans-
lation into the finger-i)rint vocabular\'. which is
never great, lies upon the shoulders of one or
perhaps two experts, but all the rest of the work
can be done bv an\- school-bov who can turn up a
word in a dictionary. To give an example offered
to the \\'ar Office Committee bv me when being
examined as a witness ; the expert, reading off a new-
set of say five finger-prints in one hand which has
come in, calls for all old records filed past containing
Abracadabra (a fanciful word of five syllables).
That word in s\llabic form might read

A-bra-ca-da-bra . or
Ab-rac-ad-ab-ra . or
Ab—ra-cad~a—bra, and so on.

Under an}- of these forms there might be several
people indicated. Vnn it would be found that onl}-

one. if an\-. would correspond exactl\- with the
person to be identified. .\t all events, that is the
helief, not easil}- to be shaken, of some hundreds of
experts working for now- about a decade, in different
countries. This means quite an extraordinary
securit\-. bevond an\thing hitherto conceived, in
regard to personal identification, but its efficiency
does not depend on aii\- one method of classification.

Having got a trustworth}- method of arranging the
records, I now had n-iade copperplate forms to receive
impressions of the fingers in consecutive or serial
order of both hands, with spaces for a lock of hair,
information as to race, sex, and so on, that some
ethnographical purpose might be served as well.
.\t the close of 1879. and in January, 1880,
I wrote out a hundred or so of circulars en-
closing a number of mv copperplate forms with
outline hands to receive imprints. One copy
made b}- me on 30th Januar}-. 1880. reads thus: —

■" Dear Sir. — I am at present engaged in a comparative study of
the nigac, or skin furrows, of the hands of diflerent races and
would esteem it as a great favour if you should obtain for me
nature-prints from the palmar surface of the fingers of any of
the (blank) race in your vicinity, in accordance with the
enclosed forms. The points of special interest are marked
(red cross) and no others need specially be attended to. Each
point must be printed by itself separately. Printer's ink put
on very thinly and evenly, so as not to obliterate the furrows
of the skin, is best. It can easily be removed bv benzine or
turpentine. In place of that, burnt cork mixed with i^ery
little oil will do very well. One or two trials had better be
made before printing on the forms. If printing should be
found too difficult, sketches of leading lines at the points
indicated would still be of very great value, taking care that
the directions corresponded with the furrows, and not in
reverse, as when a simple impression is taken. If any one
finger, and so on, comes out badly a piece of paper can be
printed and pasted on at the proper place. I enclose as a
specimen a fiUed-up form. [The fingers printed in the proper
spaces and the important " points " each marked with a red
cross.] As novel and valuable ethnological results are
expected from this enquiry, I trust this may form a sufincient
excuse for asking you to take so much trouble. Please return
any forms which may be filled up to the above address.

" I am, &c.,

'■ H. F-i^ULDS."

The response was quite disappointing. Some
thought it was an advocate of palmistry looking for
cats" paws : most took no notice whatever. I tried
in the same wa}- to get imprints from lemuroids,
apes and anthropoids. On the 15th T'ebruar}- of
the same \-ear (1880), I wrote to Charles Darwin,
sending specimens of prints and an outline of my
first results, and requesting him to aid me in obtain-
ing access to imprints from lemurs, monkevs and
anthropoids, as I had found them to show- lineation
patterns which I hoped might be serviceable for the
elucidation of man's lineage. I had failed to find
an\- trace of previous notices of the subject in
anatomical or recent biological works. The few
earl\- notices which have }et been found I hope
to deal with pretts- fullv on .some other occasion.
The great naturalist's reply, two }-ears before his
death, was as follows : —

Knowledgh. Volume XXXIV (lyil).

To face page 138.

The back view of a Japanese labourer most elaborately tattooed in colon

April. 1911.

KNOWLEDGE.

139

Via Brindisi. Down,

April 7th. ISSO. Bhckenham, Kent.

Railway Station,
Orpington, S.E.R.
Dear Sir, — The subject to which you refer in your letter
of February 15th, seems to me a curious one which may turn
out interesting ; but I am sorry to say that I am most
unfortunately situated for oft'ering you any assistance. I live
in the country and from weak health seldom see anyone.
I will, howe\er. forward your letter to Mr. F. Galton. who is
the most likely man that I can think of to take up the subject
to make further enquiries.

Wishing you success,

I remain, dear Sir,

■^'ours faithfully.

(Signed! CH.\RLKS DARWIN.

The original of the above holograph letter, w ith
envelope addressed by Mr. Darwin and duly post-
marked, along with the proof sheet of the first
copperplate form made for me in Japan, is now in
the Library of the Royal Facult\' of Physicians and
Surgeons. Glasgow. On October 28th, in Xcitiirc
appeared a contribution b\' me, '' On the Skin-
furrows of the Hand."' %\hich was printed in the
Index Metiiciis of the United States as the hrst
recorded contribution on that subject. .At the
International Medical Congress about ten months
afterwards. Dr. Billings, then editor of the
Index, said in a speech — " Just as each indi-
vidual is in some respects peculiar and unique,
so that even the minute ridges and furrows
at the end of his forefingers differ from those
of all other forefingers, and it is sufficient to
identify," and so on (Report in The Times, August
5th, 1881). M\' proposal was certainK' the first
[jublic suggestion to establish a scientific method of
identification on the basis of finger - prints. Sir
William Herschel wrote soon afterwards to Xatiire,
admitting my priority of publication, but stating that
he had used a method of finger-prints in India before
this. There is no dispute bet\\een Sir William
Herschel and myself, as each had reached his own
conclusions quite independently. This little personal
matter was discussed in Xatiire (October, 1894) and
in Gegeiihaiier's Jahrbiich for 1905. in which the
date of my first contribution is considered the
starting-point of recent study of the subject. The
copious literature which soon sprung up was of
every kind, with some appalling journalistic varieties
in America. In 1881, Monsieur Bertillon, of Paris,
brought out his delicate anthropometric system,
to which the independent finger-print method from
England was superadded. It therefore began to
appear to the official, and even to the infallible
encyclopaedic mind, that finger-prints were merel\-
an element in the French system of identification,
or Bertillonage. The finger-print method alone was
used in a United States expedition in 1882, and it
was tried in San Francisco, as afterwards in South
.Africa, to identify the fluctuating population of
Chinamen. In the year after my final return to
England greatly renewed interest was aroused in the
subject. Herbert Spencer tried to explain the origin of
theridges in an article in The Xinefeeiith Century, ^lav.

1886. Sir Francis Galton, to whom Charles Darwin
wrote to me in 1880 that he would refer the matter,
began the study, as he states on j)age 2 of " Finger
Prints," in 1888. In that same 3ear, Inspector
Tunbridge from Scotland Yard v,r„-, ofliciall_\-
appointed to in\estigate nu- propc.sals. No report
has ever been made public, but Mr. Tunbridge told
me that he feared the method was too fine to work, and
said that nothing could be done at least without fresh
legislation. Some years afterwards he was appointed
to New Zealand, where he was the means of inducing
the prison authorities and police to appl\- the
method, which has been no\\' in successful operation
all over .Australasia for some years ; so Mr.
Tunbridge wrote to me in 1907.

In 1894, a committee appointed b\- Mr. Asquith
met and finally, after some rambling conclusions,
adopted Bertillonage with finger-prints as some help,
the former being used as the basis of classification.
The proposal was absurd, and it was soon found, as
might have been foreseen, that finger-print patterns
yield a far firmer and more searching basis of
classification in themselves than the other method,
and need no auxiliary crutches.

In 1897, the two associated methods began to be
applied in British India: while in civil cases there, as
in attestations, pension claims, and so on. the finger-
print method was used by itself.

In 1901. the ten-finger methodin serial order, exactly
as originalh' advocated by me in 1880, was finalh"
adopted in England, after other trials, and has
met with an immediate and triumphant success in
giving rapid and easy identifications of recidivists or
old professional criminals, often living under aliases.
Monsieur Bertillon. who at first did not use finger-
prints at all, wrote to me officially that since 1894 the
two methods had been jointly used in Paris, and that
greater securit\' was now felt in identif\ing. In
1902, finger-prints took the place of bodily measure-
ments in Austria-Hungary, being easier of application,
and less likely to give varying results. Two years
afterwards Spain followed suit, our Inspector Arrow-
taking some charge. The method had been worked
before that period in Buenos Ayres with success. .A
private service for identification by the finger-print
method was. I believe, instituted in Belgium by
Dr. de Laveleve. but I have heard no report of
results.

It is a curious fact, luit true beyond question, that
the effectiveness of the method has proved to be the
chief obstacle to its more extensive application. In
short its miraculous effect in tearing the mask from
old criminals wh.o try to veil their identity by an
alias, has created a horror of it amongst the class
from which man\- recruits used to be drawn for
Arm\' and Navy.

In conclusion, I should like to point out that
there are five distinct ways in which Dact\-lograph\-,
or the scientific study of finger furrows, may be
serviceable : —

(1) In relation to tlie problem of himian lineage.
Much tentati\e work has been now done in this field

140

KNOWLEDGE.

April, 1911.

bv many workers, and a scientific pathway begins to
open up before us.

(2l In eluc-idatint,^ the relations of front and liind
limbs: Professor Bowditch. of Harvard, wrote to me
that he had earl\" begun an enquiry into this subject.
It promises to yield results of interest, but more
workers are required.

(3) In identif\ang for life insurance, pensions,
passports, affidavits, cheques, signing deeds, and so
on. Again, in identif\'ing the dead b\- former
records, after battle, flood, fire or earthcpiake.

(4) In identif\'ing old convicted criminals who
have assumed other names.

(5) In testing e\idence of bodily presence at a
scene of crime by bloody finger-marks, sweaty or
greasv smears on glass windows, wine glasses, lamps.
or cash boxes and the like, or indented impressions

on putty, wax, paraffin and so on. Faint impresses
can be revived ; invisible ones quite clearl_\- brought
out b\- chemical means : imprints in relievo may be
photographed and made clearh' intelligible to a jury.
(See figure 5 — a smudge from a finger.)

The last, and I think b\- far the least, of these
once potential, now actual, utilities has taken the
deepest hold of the popular imagination, and has
seemed, to me at least, to threaten some danger to
the innocent bv its often ignorant and unscientific
application. The method is not " mathematical " as
certain officials are ne\-er tired of repeating, but
demands common sense and the use of their own
eyesight and mother wit b\' the plain men in the
jur\- box. It is essentialh- English, and ever\- accused
person in the dock is as able as a judge, or counsel,
or official witness, to test its validity.

W () U N D S IN TREES.

Some interesting illustrations are given in the
March number of The Cmintiy Home of wounds in
trees that have successfully closed o\er. and others
which will never properh' heal, ^^'e are enabled to
reproduce some of the pictures here, b'igure 1
shows a well-healed wound. In I'igure 2, the
process of healing having been slow, the exposed
wood has rotted awa\- and, there being nothing
to keep the healing tissues in their proper place,
\he\ are turning inward, with the result that if the
wound is left to itself it will never heal. Figure 3
depicts a branch on which a snag has been left,
and, so long as it remains, it will pre\ent the

edges of the healing tissue from meetmi

The

article emphasises the need for more attention
to be paid to trees, on account of the danger
caused by their unexpected fall. Mention is also
made of the \\ork of the tree doctors, whose
advertisements are seen in the columns of

American news-
papers. Their
services would
be useful at a
time when the
trees are lopped
in the first in-
stance, and also
to repair the
damage caused
b }• ignorant
labourers, who
are o n 1 \' too
commonh- em-
ployed to cut
trees, regardless
of the fact that
the\' are living
creatures.

A wound
not heal.

The Cftuntry llonw.

that will

By the courtesy o/ I'hi- Count7y Home.

FiGURi-: 1. A wL'll-lR-uk'd wuiind.

By the courtesy of The Country Home.

FiGUKi-: J. A snag which pix-\cnts healing.

CORRESPONDENCE.

ORIGIN OF THE FINGER PRINT METHOD.
To the Editors of " Knowledge."

Sirs, — Kindly correct an error in your February number.
Page 45, about Fingerprints. You quote Sir Francis Galton
as saying in his Reminiscences " that Sir William Herschel
in India had experimented with them since 1887." I do not
know where you got this date from, but Galton never gave it.
.\s a matter of fact before I left India in 1878 I had been
experimenting for twenty years (Galton says " many years "I,
and had successfully established, not only the individuality,
but the practical persistence of the pattern, as an unfailing
method of identification, before any one else had entertained
the idea. When I left India the system was in public use
with the knowledge of the Heads of the Registration Depart-
ment, and of Gaols, as well as for Pensioners, and in my own
Court, and was matter of common knowledge in Bengal. The
<jOvernment of Bengal had known of it from me many years
before 1878, as a means of preventing forgery during the
Indigo disputes in 1861 and 1862.

I trust you will do me the justice to insert this letter in your
next number.

I am engaged at present in arranging my records for
publication in facsimile by the Clarendon Press.

W. J. HERSCHEL.

.\ METEOR.
To the Editors of " Knowledge."

Sirs. — A beautiful meteor was seen here (Sunderland.
February 16th I about 5.33 p.m. The head was almost as
bright as \'enus, but larger in appearance. It left a trail of
light behind it which appeared to be reddish in hue : it was
\isible several seconds.

I am not an astronomer, but think that the note would
be of interest to vour readers.

F. H. S.

THE SUN'S RE\"()LL"T10N.

To the Editors of " Knowledge."

Sirs, — As a student of .-Vstrological lore. I sometimes draw
a figure for my birthday anniversary. But I find the time for
the sun's return to its place at birth varies from year to year.
For instance, at the time of my birth the sun was in Pisces
24-41, which occurred at 10 a.m. on March 15th, the year of
Hiy birth. But in 1910 the sun came to that point sixteen hours
later, or at about 4 a.m. on the 16th. and this year later still, \iz..
about 9.30 a.m. on the 16th. Can any of your readers kindly
explain how it is that the sun does not return to the same
point in the Zodiac at the same time everv vear ?

H. A. B.

IS SPACE INFINITE?

To the Editors of " Knowledge."

Sirs, — The following extracts from Professor Pickering's
Article in Popular Astronomy of August last are of special
interest in connection with Mr. Barclay's letter on the subject
of the "Eternal Return." The suggestion that space is curved
may be welcomed by many of your readers as an alternative
theory to that of Laplace and others who ha%e assumed that
space and time are necessarily infinite.

H. PERIAM HAWKINS.

"Everyone who considers the question of proceeding indefinitely
along a straight line must feel the impossibility of coming to a point
where there is no space beyond him, and j'et at the same time he must
feel that infinite space is itself an impossibility. To avoid this difficulty
it has been suggested that space is curved, with a definite radius and
direction of curvature at every point. In other words we should accept
the idea that plane triangles and rectangular co-ordinates are merely a
close approximation to fact, but that all figures are really constructed in
spherical co-ordinates.

"Now it is a properly of infinite space, of any number of dimensions,
that if it be properly curved, and inserted in space of one higher dimen-
sion, it will become finite. Thus if infinite space of one dimension,
represented by a straight line, be properly curved and inserted in a plane
it 'vill become the periphery of an ellipse ; if uniformly curved it will
become that of a circle. Similarly, if space of two dimensions, repre-
sented by a plane, be properly curved and inserted in tliree-dimensional
space, it will become the surface of an ellipsoid. Similarly, if ordinary
or three-dimensional space be properly curved, and inserted in space of
four dimensions, it will become finite in volume, and represent what would
correspond to the surface of a fourth-dimensional .solid. Thus, if we
.should go far enough east, we should reach the west, if far enough north
we should reach the south, and if far enough into the zenith we should
re.ach the nadir."

" If it is difficult for us to imagine infinite space, it is still more so to
comprehend infinite time. As we go back eternally through the ages
how is it possible for there to be still an infinity of time before that ?
Vet we cannot conceive of an actual day or instant before which time
did not exist. In graphical solutions time is represented by a straight
line, and may be compared to space of one dimension. But suppose
that time, too, is curved, and has another dimension that we have not yet
detected. Time then may be represented by an ellipse or a circle, and if
we go back far enough into yesterday, we shall arrive at to-morrow.
Of course, we s/iould not live our lives over a^ain, because matter in the
ineantitne would have changed, and when the present day again arrives,
it will be upon a very different universe. Both infinity of time and a
return of time seem to us now impossible. If the latter is the more
difficult to comprehend, may it not be simply because it has not occurred
to us before ? "

THE NEW MAP OF THE MOON.

To the Editors of " Knowledge."

Sirs, — Our nearest companion in space has. ever since the
invention of the telescope, attracted a good deal of attention.
Many have been the attempts to map its surface. Perhaps
the first re.ally useful map was that of Beer and Madler. thirty-
seven-and-a-quarter inches in diameter, published in 1834. those
previouslyissued by Hevel and Tobias Mayerbeing much behind
in detail, as also were those of Russell and Blunt. Lohrman's
work was on the same scale as Beer and Miidler's. but. owing
to the failure of his vision, was not completed until produced
under the editorship of Schmidt, some thirty years ago. In
1876. Xeison issued a useful book on the Moon, containing a
capital map two feet in diameter. But in 1878, Schmidt's great
map, six feet in diameter, was published, the labour of thirty-five
years. Since these maps were issued a new era has dawned
in selenography ; the telescopist is reinforced by photography.
The latter, whilst it misses the sharpness of telescopic vision,
puts detail in its accurate place. The new map has been
constructed from combined telescopic and photographic obser-
vations, on a scale of se\enty-seven inches to the moon's diameter,
by Mr. Walter Goodacre, the director of the Lunar Section of the
British Astronomical .Association. It has taken seven years
to accomplish this noble work. Its accuracy may be judged
when it is considered that it is based " mainly on 1,443
measured points on the lunar surface, made by Mr. S. A.
Saunder, ^I..A.. F.R.A.S..and pubhshed in the Memoirs of the
Ro^-al Astronomical Society, Volume LVII." The sketches
of many of the best observers, including the late Major P. B.
Molesworth and Mr. Gopdacre, have been used in the con-
struction. This monumental work, which has been exhibited

141

42

KNOWLEDGE.

Apkll. ion.

both before the Royal Astronomical Society and the British THE MOON AND THE WEATHER.

Astronomical Association, is now being reduced to a scale of To the Editors of " Knowledge."

sixty inches, and divided into twenty-five sections. Each Sirs, — May I make a few notes on letters in vour

section is twefve inches sqnare. with an overlap of half correspondence columns of July and September of last year, as

an inch, maliing the actual size thirteen inches. The map a contribution towards discussion concerning the influence of

is nndonbtedlv the best one yet issued, and should prove the moon on the weather.

MAP OF THE MOON.

SECTION VII.

■•'O"'-- N D^J^v^, b> WaLTER GoODACRE. eras 1110

Figure 1. .A reduced facsimile of one of the sections of a New Map of the Moon.

a real incentive to the study of selenograpli\-. The fact
that the moon's surface has been mapped far more accurately
than has much of our own world does not alter the other fact,
that there is very much more to learn concerning it. Mr.
Goodacre has kindly given permission for the reprodnction of
one section (see Figure 1), and this shows how well he has
accomplished his work. It is being produced by subscription
at the really too low price of 22s. 6d.. about a quarter the
price of Schmidt's. It is to be hoped tliat the number of
subscribers may verv soon be found to permit of the publica-
tion being completed. I'RANK C. DENNETT.

Mr. Strickland, in July — page 269 — says: " Nasmyth believes
it to be demonstrated that as a rule the sky is clearer at full
moon than at the quarters." (If fewer clouds, then less rain ;
what do the rain-gauges say to this?) "Effect of moon is
strongest in Winter in England." (Are tides highest in Winter?)
"Equatorial regions .are. par excellence, solar regions and
lunar influence is reduced to a niiniuunn." (What about height
of tides there coniiiared with temperate regions?)

Rem.irks on height of tide in Bay of Fundy, and in
Mediterranean. — The almost absence of tide in the Mediter-
ranean, is dependent u|i.in the small inlet from the Atlantic,

April. 1911.

KNOWLEDGE.

143

;uid the high tides in other localized places upon the special
configuration of the coast — the narrowing of the waterway,
as also in the Severn and the Wye in England.

If the moon raises tides in the ocean, a much higher tide
should she raise in the lighter air ; if so, does her attraction
counteract the effect of the increased weight of air on the
barometer ?

.'^t the commencement of his letter Mr. Strickland says: "I
hold that the negative they (the official meteorologists) think
they have proved, is not proven." (Do not their statements
rest on facts observed at Greenwich ?)

In your September number, — page 372 — Mr. Ditcham writes
to show that the high tides in the Fraser River bring up
warmer water from the sea, and so warm the climate, but is
not that almost as indirect a result as it would be if they
brought up a log of wood which
he cut into firewood and warmed
his house with ? Or again, if
the liver were dammed back,
the warming effect of the moon
would be prevented to those
above the dam. I li\e on the
watershed between the Thames
and the Channel where there
are no tidal streams, and can
find no sign of the moon"s in-
fluence on our weather.

There is also a letter from
Mr. Ditcham. in your February
number of this year, the figures
of which, I am sorry to sa\', I
cannot understand, whether they
give the height of tides, or some
barometric weights, I do not
know, nor can I see any con-
nection between the figures and
the dates. L. J.

rODUK.A. SC.\LES.

To the
Editors of " K.xowi.EDGE."

Sirs, — Mr. Plaskitt. in his
courteous reply to my letter,
has almost entirely ignored the
point I tried to drive home, that
the available aperture of any
wide apertured micro-objective
is limited to the back lens
being three-quarters filled with
white light only. That I filled
up the whole of mine with such
light, 1 ne\er asserted. Indeed.
1 could not have done so had I
tried, my condenser being a dry

one. For all that, I could always break down the iin.age in my
-objective, of 1-40, upon any object mounted in balsam, by
using the largest stop of the condenser. What I did claim,
howe%er, and do claim now, was that I worked the objecti\e
with the largest aperture it would stand — rather a different
matter.

Upon the points he has raised, save one, 1 have nothing to
fight ; the laws of refraction are fixed. It is only upon the
application we differ. Neither is it necessary on my part to
try the experiments he suggests in the last paragraphs of his
letter, for already I agree.

This question of full versus available aperture is a very old
one with me — twenty years old, in fact. On referring to the
back numbers of the journal of the Ouekett Club, I find that
Mr. Ingpen raised exactly the same point in 1S91, in connection
with some objects exhibited by myself. He said that he
" wanted to employ the greatest powers of the objective to
be obtained between 1 and 1 • 4, and did not see how they
could be made use of upon a dry object,"' — at the same time
advocating the use of a dense medium.

To this, Mr. E. M. Nelson replied that he " found, on the

"Ml^!

Figure 2.

Part of a Podura Scale, showing a portion of the right hand

side of the Scale reproduced in " Knowledge," Volume

XXXIll. p.age 535, Figure 2, enlarged 2i times to show

intermediate lines.

other hand, if the object was drj- on the cover glass, it would
bear the test better than if in a mediur;i. So long as it was in
optical contact with the front of the lens they could get in all the

spectra Photographs of objects mounted in the

denser medium looked all smeared over." He had never seen
a decent critical im.age produced from anything in a dense
medium. He did not know the reason, unless it might be
that the treatment undergone by such might have the effect of
spoiling them.

This appears to be a question of theory versus practice, and
reminds me of the German Professor who forbade his students
to adopt a certain formula, because, though it worked out well
enough in practice, in theory it was all wrong. In the present
instance the theory was that an oil-immersion objective must
have an oil-inmiersion condenser of the same aperture, to

develop it. Workers bought the
oil-immersion condensers and
then innocently stopped them
down until they got the working
image, thinking all the while
that they were utilising the full
aperture of the lens. My chal-
lenge to them was to produce
something under an oil-innner-
sicm condenser I could not show-
equally well with a dry one ; a
challenge ne\er taken up. This,
howe\'er. is \'ery old historj' now.
I shall be only too pleased
for the Editors to send Mr.
Plaskitt my address, and equally
pleased to receive the enlarged
prints promised. I know how-
easy it is to miss little points in
a small print which are perfectly
obvious when they are further
magnified. May I suggest, liow-
e\er, that with the Editors'
permission, Mr. Plaskitt sends
one enlargement to be repro-
duced for the benefit of the
readers of " Knowledge." I
am sending one with this letter
hoping for that permission,
because, I take it. the truth is
what we both want. If this be
granted, that is, the Editors'
consent, the one of his to go
best with mine would be the
one with the oblique lighting
across the scale.

Yet, even then, the credi-
bility of appearances will still
remain an outstanding question.
I. at least, am not prepared
to state with certainty what the secondary lines denote, and I
do not suppose Mr. Plaskitt is more positive. We can only
judge of the relative truth by the method of production.
Leaving my own opinion out of the question altogether, the
weighty authority of Mr. E. M. Nelson and the late Dr.
Dallinger cannot be ignored, who both advocate the central
cone of illumination, as opposed to oblique light. The last, in
his presidential address to the Ouekett Club, in 1891,
speaking of the new apochromatism, says : '' It gives certainty
and precision to all work done .... but w-e must
be careful not to re-introduce the ghostly element by false
interpretation. I am increasingly convinced of the possible
danger of employing shafts of oblique light only in one azimuth.
The peril of misinterpret.ation is enormous."

Again, of the new apochromatic of 1-60 N..-\., it is claimed
that '■ it is a triumph of the optical firm w-hich produced it.
. . . . But I would hasten to say, that I would not
trust a single result produced by its means, when oblique

light in one azimuth is employed It is fatal to its

truth. We can absolutely .get almost any desired result with
it. It is a very optical Witch of Endor for calling up ghosts

144

KNOWLEDGE.

Apkii. 1911.

and ghostly visions." Surely here is evidence enough, and
as for this one lens, all the result of direct experiment.

Mr. Plaskitt c_ontends that if when using an oil-immersion of
1 -40 with the full aperture, that is. with the back lens filled
with white light, I then stopped it down until only three-
(juarters was full, I should be getting mncli nearer • 75 than
1 -40. an aperture not so much as a good dry quarter as to
resolving power. Well, that is a matter easily settled. I still
have the scale from which the photograph with my
apochromatic was taken, and shall be most happy to wait
upon him with it. if his home is in London. If he can then.
with a dry glass, produce the same appearances upon it. 1 u ill
concede his point. This, at least, would be a short way out
of the discussion. -j. -,- c;-\iitH

THE ETKRXAL RETURN.
To the Editors of "Knowledge."

Sirs, — Mr. H. D. Barcla\', in the February issue of
" Knowledge." raises the oft-recurring and apparently
insoluble question of Eternal Return, but the precise difficult\'
he is in is not altogether clear.

That time and space are infinite will admit of little doubt ;
that the sum total of forces in the Universe is also infinite
is, though open to question, probably also true. The
fact of their being constant need not necessarily impair
their infinity. (Can infinity itself not be constant ?) Their
sum total may be constant, but their component parts are
subject to perpetual changing and interchanging. It is
this continual changing and lack of equilibrium that is of
the very essence of force. Pre-suppose equilibrium, and
our conception of force is gone. We might, indeed, say
that this lack of equilibrium is a permanent and essential
factor in the Universe. It is, as it were, the attribute of force
or energv itself, and, in this sense, is infinite and eternal.

The argument, as stated by Mr. Barclay, pre-supposes this
permanence : — " If these forces could ever attain a position of
balance it would have already happened, as an infinity of
time has passed." Not having happened, it follows that this
condition of out-of-balancc is infinite, and force, therefore, is
also infinite.

It is curious to note th.it Dr. Le Bon is brought in as a
supporter — indeed as one of the discoverers — of the eternal
return hypothesis, but on what ground it is difficult to
understand; for, in Dr. Le Bon's view, matter is constantly
" dis,sociating " and slowly but surely returning to the ether
from which it was originally derived. Once it has all returned,
there is an end of matter and energy alike. This is a subject I
happen to have alluded to in the January issue of the
Westminster Reviexc, and if Mr. Barclay will refer to
it he will see that Dr. Le Bon's teaching (if I read him

aright I is not that of "eternal return" but of "no return."
It is true that here and there he lets fall a phrase which
betrays a doubt on the subject: but in spite of these lapses it
is clear that his doctrine of dissociation is closely bound
up with the doctrine of "no return." — matter and
energy are constantly being dissipated, and apparently are
lost for all time. It is not an inspiring doctrine,
and seems purely gratuitous : for there is nothing in his
experiments that necess.arily leads to any such inference,
while the operations of Nature in general point altogether the
other way. Nothing is clearer than that Nature, within the
bounds of our experience, works, both on a large and on a
small scale, in cycles of some sort. Almost all her operations
are rhythmic. There is a constant ebb and flow : an evolution
and a devolution. If this is the case in regard to phenomen.a
within our limited experience, is it not a reasonable inference
that this evolution and de\olution extends far outside our
experience and beyond our conception ? — that it is, in fact,
infinite and universal.

The following quotations fr(.)ui Dr. Le Bon's "The Evolution
of Matter" (Book VI. Chapter VIII. I sufficiently indicate his
\ lews on the subject : — " We now know that matter vanishes
slowly, and consequently is not destined to last for ever." . . .
" What is the fate of the atom of electricity after the dis-
sociation of matter ? Is it eternal while matter is not ? "
. . . . " Once it [the electric atom] has radiated away
all its energy, it vanishes into the ether and is no more."

. . . " This last, therefore, represents the final nirvana
to which all things return after a more or less ephemeral
existence."

One saving clause (in the same chapter) is as follows : —
■' Nothing leads to the belief that they [i.e., things in general]
had a real beginning or that they can have an end."

Thus we see that Dr. Le Bon's teaching is unmistakably in
the direction of the final destruction of matter and energy,
although the last quotation I have given betrays something of
an open mind on the subject, — a subconscious admission though
it possibly may be.

.As often as we recur to this problem we are inevitably met
with this consideration : that, from the nature of the case, the
finite cannot grasp the infinite ; and whatever our speculations
may be, we must, of necessity, always labour under this
disability. .As Wallace has said : " Of infinity, in any of its
aspects, we can really know nothing, but that it exists and is
inconceivable."

This, however, is no reason for withholding our speculations,
so long as they have a substantial basis of fact ; for it is only
by pressing them forward that we can ever hope to in any
degree qualify our present limitations. ... ,- rTcu-viiv

NOTICI'.S.

THE ZOOLOGICAL SOCIETY, ADDITIONS TO THE
MEN.AGERIE. — Daring the month of February no less than
one hundred and twenty-three additions to the Zoological
Society's menagerie were registered. Among them are the
following animals which are new to the collection: — .A Dwarf
Mongoose ( Helogale varia), from Mombasa, presented by
the Rev. W. Douglas Braginton, on Feb. 27th ; a Black-footed
Polecat (Putoriiis iiigripes), from North America, received in
exchange on Mar. 16th; two Dybowski's Deer (Cervns
hortiiloriiiu ), from Manchuria, presented by Sir Edmund
Loder, Bart., F.Z.S., on Feb. 23rd; and an .Aldunati's Finch
(Phrygiliis aldnnatiil, from Chili, presented by Miss Phillis
True, on Feb. lith.

ROYAL INSTITUTION.— The following are the Lecture
.Arrangements at the Royal Institution after Easter: —
Mr. J. E. C. Bodley, Three Lectures on (1) Cardinal Manning;
(2) The Decay of Idealism in France, and of Tradition in
England; (3) "The Institute of France; Professor Frederick W.
Mott, Two Lectures on the Brain and the Hand; Professor
W. W. Watts, Two Lectures on (1) The Ancient Volcano of
Charnwood Forest (Leicestershire); (2) Charnwood Forest
and its Fossil Landscape ; Professor R. W. Wood, of the

Johns Hopkins University, Three Lectures on the Optical
Properties of Metallic Vapours (Illustrated) ; Dr. W. N. Shaw,
Two Lectures on .Air and the Flying Machine: (1) The
Structure of the Atmosphere and the Texture of .Air Currents ;
(2) Conditions of Safety for Floaters and Fliers; Mr. T.
Tliorne-Baker, Two Lectures on (1) Changes effected by
Light ; (2) Practical Progress in Wireless Telegraphy
(Illustrated) ; Professor Selwyn Image, Three Lectures on
(1) John Ruskin; or. the Seer and Art; (2) William Morris;
or. the Craftsman and Art ; (3) Walter Pater ; or, the
Connoisseur and .Art; Mr. W. P. Pycraft, Two Lectures
on Phases of Bird Life: (1) Flight; (2) Migration; and
Mr. W. L. Courtney, Two Lectures on Types of Greek
Women ; Xausicaa and the Homeric Women ; Sappho and
the Aeolian Poets ; .Aspasia and Pericles. The Friday
Evening Meetings will be resumed on April 2Sth, when a
Discourse will be given by Professor W. M. Flinders Petrie
on The Revolutions of Civilization. Succeeding Discourses
will probably be given by Professor Martin O. Foster,
Professor William Stirling, Professor R. W. Wood, Professor
Gilbert Murray, Commendatore G. Marconi, Professor Svante
.Arrhenius. and other gentlemen.

THE FACE OF THE SKY FOR APRIL.

Bv W. SHACKLETON, F.R.A.S., A.R.C.S.

The Sun. — On the 1st the Sun rises at 5.39, and sets at 6.29;
on the 30th he rises at 4.37, and sets at 7,17. The equation of
time is negligible on the 16th and 17th, hence these are
convenient days for the adjustment of sundials, as only the
longitude correction is needed. Sun-spots may usually be
seen on the solar disc, but they are small, and not numerous.
The positions of the Sun's axis, equator, and heliographic
longitude of the centre of disc are shown in the following
table : —

Venus :-

Date.

Axis inclined
from N. ptiint.

Centre of Disc

S. of
Sun's Equator.

Heliographic

Longitude of

Centre of Disc.

.\pl. I ...

26° l8'W

e 31'

188° 56'

,, 6 ...

26' 26' W

6" 13'

122" 58'

,, II ...

26° 23'W

s° 52'

56° 58'

„ i6 ...

26° lo'W

5' 29'

350° 56'

., 21 ...

25° 45'W

5' 3'

284' 54'

,, 26 ...

25° 9'W

4^ 3.^'

218" 51'

Mav I

24° 22 'W

4- 0'

152" 46'

6 ...

1

23^ 24'W

3 35'

86' 41'

On April 28th, a total eclipse of the Sun takes place. It is
invisible in this country ; the path of totality lies almost
entirely over the Pacific Ocean, no large piece of land falling
in the shadow, A party of observers left England in F"ebruary
for Vav-au, one of the islands in the Tonga or Friendly Group,
in Mid- Pacific, where totality lasts for about three-and-a-half
minutes.

The Moon : —

Date.

Phases.

H.

M,

Apl. 6 ...

„ 13 ...

., 21 ...

,, 28 ..
May 5 ...

I

•

1)

First Quarter

Full Moon

Last Quarter

New Moon

First Quarter

5

2

6

10

I

55 a-"-'-
37 P-m-
36 p.m.
25 p.m.
14 p.m.

Apl. 2 ..
., 18 ...
.. 30 ...

Perigee

Apogee ...
Perigee .

8
6
9

12 a m.

42 a.m.

0 a.m.

OCCULT.^TIONS. — No bright stars
midnight either in April or May.

are occulted before

THE PLANETS.

Mercury : —

Date.

Right Ascension.

Declinaiioii.

Apl. I ...
,, II ...

21
M.ay I
,, ' II ...

b. m.

1 24

2 25
2 58
2 55
2 35

N 9° 25'
16" 52'

19" 55'

18' 11'

N if 48'

Mercury is an evening star throughout April. The planet is
at greatest Easterly elongation from the Sun of 19' 42' on the
15th. when he sets W.N.W, about 8.55 p,m. This elongation
is a favourable one on account of the high declination, and
there should be no difficulty in seeing the planet from the
15th to the 25th, as he sets about two hours after the Sun.

On May 5th, Mercury is in inferior conjunction with the
Sun,

Date.

Right Ascension.

Declination.

h. ni.

Apl. I ..

2 3'

N 1 5'' 10'

II ..

3 19

19" 7'

., 21 ...

4 9

22° 15'

Mav I ..

5 0

24° 25'

II ..

1

5 51

N 25" 29'

Venus is a brilliant object in the evening sUy, lo(>l<ing
W.N.W. after sunset.

The planet is well placed for observation, appearing fairly
high above the horizon at sunset, and not setting till 9,20 p.m.
on April 1st, and 10.50 p,m, on May 1st,

As seen through the telescope the planet appears gibbous,
0-8 of the disc being illuminated, whilst the apparent diameter
of the disc is 13". On account of her brightness the planet is
fairly easy to pick up with the naked eye before it is dark,
and this is the best time for making observations with the
telescope, for Venus is a severe test for the achromatic
qualities of any refractor if observed on the dark background
of the sky ; seen in a lighter sky the outstanding colour, in the
telescope, due to want of perfect achromatism, is not so
obtrusive, and a better view of the planet is obtained. The
Moon will appear near the planet on April 1st, being only
0" 14' to the South as illustrated in the March issue, whilst on
May 1st the Moon will be li to the North.

^^\RS : —

Date.

Right .\scension.

Declination.

h. m.

Apl. I ...

21 6

S 17" 51'

II ...

21 3&

I5'-' 42'

., 21 ..

22 5

13" 19'

Mav I ...

22 34

10 45'

,, II -..

23 2

S 8" 3'

Mars is a morning star rising E,S,E, about 3.30 a.m., near
the middle of the month. He is situated first in Capricorn, then
in Aquarius, The planet is unfavourably placed for observa-
tion and since his apparent diameter is only 5" telescopic
observations are difficult except in large instruments.

Jupiter : —

Date.

Right .Ascension.

Declin.ation.

h. ni.

1 Apl. I ..

14 44

S 14° 28'

' .. II ...

14 40

14-^ 9'

i ,, 21 ...

14 30

13° 47'

Mav I ...

■4 31

'3° 23'

., II ...

14 26

S 13° 0'

Jupiter is a brilliant object in the late evening sky looking
South-East, The planet is in opposition to the Sun on May
1st, hence about this date he appears South at midnight. On
April 1st the planet rises at 9.20 p.m., and on May 1st at
7 p.m., and is visible throughout the night. The equatorial
diameter on the 15th is 43" -6, whilst the polar diameter is
2" -8 smaller; this polar flattening is a conspicuous feature of
Jupiter, and is readily obse-'vable in small telescopes; also the

145

146

KNOWLEDGE.

attendant bright moons and belt inarUinKs mi the phinefs disc
form interesting objects of observation. The smallest tele-
scope magnifying about 40 times, shows the planet of the same
apparent diameter as the Moon seen with the naked eye. and
the surface markings may readily be observed.

The following table gives the satellite phenomena visible
before midnight : —

0" Capricorni : he is in quadrature on the
the stationary point on the 4th May.

April. 1011.

20th April and at

A

^■

o

2

J

H

6

=

OJ

D

o

■r.

a.

P.M.-s.

H. M.

d

a!

P.M.'s.

H. M.

0

'T.

S

P.M.'s.

H. M.

Apl.

,\pl.

Apl.

TIT.

■|r.

E. Q 53

15

1.

tc.

D. 10 42

=3

1.

Sh.

E II 57

7
8

T

Sh.

1. II 27

16

I.

,Sh.

K. 10 ^

24

1.

Oc.

R. Q 22

I

Or

R. II 28

16

1.

■IV.

E. 10 22

2g

111.

Kc.

I). 8 27

III

Sh.

T. 10 15

22

II.

Sh.

T. Q ?3

2Q

III.

Kc.

R. 0 49

IT

III.

Sh.

E. II 56

22

II

IV.

I. in I

30

I.

Sh.

I. II 3Q

IT.

Sh.

E. g 3g

23

1.

Sh.

I- « 45

30

1.

I'r.

I. 11 40

■5

II.

Ir.

E. 10 iS

21

1.

IV.

I. 9 56

Neptune:

—

Date.

Right Ascension.

Declination.

Apl. I ...
May I ...

ll. ni. s.
7 20 55
7 22 5

N 21° 31' 41"
N 21" 30' 19"

Neptune is on the meridian at 6.45 p.m. on April 1st and at
4.47 p.m. on May 1st, and sets at 2.46 a.m. and 0.49 a.m.
on these dates. The planet is situated in Gemini about
il degrees S.E. of the star 5 Geminorum.

Meteor Showers: —

" Oc. D." denotes the r^is.^ppea^.-lllce of the Saleilile behind the disc, an<I
''Oc. R." its re.ippearance ; " Tr. 1." the ingress of a transit across the disc, and
"Tr. E." Its ei^ress ; " Sh. I." the ingress of a transit of the shadow across thf disc,
and ".Sh. E." its egress ; "' Ec. D." denotes disappearance nf Satellite liy Eclipse,
and " Ec. R." its reappearance

Saturn : —

Date.

.■\pl. I

Mav I

Right Ascension.

2 IS

Declination.

11° 2.S'

12" b'
12" 43'

Date.

Rad

ant.

Name.

t'haiactetistics.

R.A.

Dec.

Apr. 17-May I
,, 20-21..-
20 22 .
30

h. 111.

16 0

17 24
l,S 4
1 9 24

+ 47'
+ 36"

+59°

T IlercuUds
TT Herculids
Lyrid Showei
0 Draconids

Small ; short.
Swift; hi. white
Swift.
Rather slow. j

Saturn is observable for a few ex'enings during the early
part of the month, when he appears in the W., between Venus
and the horizon. During the greater part of the month the
planet appears in too bright a portion of the sky to be observed.
On Mav Ist the planet is in conjunction with the Sun and
hence will be unobser\able for some weeks tdllnwiiig.

UraN'US: —

Dale.

Right

.■\sceiision.

Declinatii

m.

Apl. 1 ...
May I ...

h.
20
20

111. s.

4 34
6 29

S 20" 53'
S 20- 49'

4S"

7"

Uranus is visible in the mornings, rising at 3. IS on April 1st
and 1.21 on May 1st. The planet is situated about 2 S.E. of

Algol mav be observed at minimum on the 3rd at 8.52 p.m.
and on the 23i-d at 10.35 p.m. Its period is 2" 20'' 49"",
fiiim which nthcr niiniiii.i ni.i\' lie drdiicrd.

Telescopic Objects: —

Double Stars.— 7 Virginis, .XIl,'' 37'", S. 0 54', mags.
3, 3 ; separation, 6"-0. Binary system; both components are
yellow, though one is of a deeper hue than the other. An
eyepiece of magnifying power of 30 or 40 is required on a 3-in.
to effect separation.

IT Boiitis, XIV.'' 36"', N. 16" 53', mags. 4, 6; separation 6".
Requires a power of about 40.

f Boiitis, XIV." 41"". N. 27'' 30', mags. 3, 6i ; separation
2" -6. Very pretty double, with good colour contrast, the
brighter component being yellow, the other blue-green.

t Boiitis. XIV," 47'". N. 19° 31', mags. 5, 7; sep.aration
2" -4. Binary; one component being orange, the other purple.

Clusters.— M 3 (Canei> Ycnatici) XIII." 38"', N. 28° 48'.
This object, though really a globular cluster of myriads of
small stars, appears more like a nebula in small telescopes.
It is situated between Cor Caroli and Arcturus, but rather
nearer the latter.

NOTICES.

PLASKITT'S SIMPLEX CALCULATOR.— We have
received from Mr. F. W. K. Flaskitt, F.R.M.S., a copy oi a
series of tables, printed on a handy card, for finding the day of
the week of any particular date. The tables are easy to work
with, the amount of calculation is small, and so far as the
results have been tested they have always been correct.
The price is 6jd. post free, from the .'Vuthor :it 12, Woodbeech
Street, E.C.

APPARATUS FOR USE IN PLANT PHYSIOLOGY.—
Our botanical readers will be interested to know that Messrs.
Bausch and Lomb are now able to supply sixteen important
pieces of apparatus from among those which have been
designed by Professor Ganong. of Smith College. To a new
catalogue of these. Professor Ganong contributes an intro-
duction, in which he says that it diverts time and energy from
the phenomena of the plant to centre them on a somewhat
slovenly kind of mechanics, and a wholly wrong ideal is
inculcated of the nature of scientific work which is based on
precision, logic and quantation. What is there peculiar in
plant physiology, he asks, that in it alone of all the sciences it is
better to do imperfect work with self-made tools than to exact
work with good tools made expressly for the purpose.

The apparatus includes a clinostat, a photosynthometer,

light screens, potometers, and smaller but c(]uallv useful
contrivances.

The list can be obtained on application to Messrs. Bausch
and Loinb's London address, 19, Thavies Inn, Holborn
Circus, E.C.

MESSRS. NEWTON & CO.'S NEW CATALOGUE.—
We have received a copy of Messrs. Newton & Co.'s new
catalogue of X-Ray and Electro- Medical Apparatus which
runs into 167 pages. By an ingenious arrangement it is
possible to turn at once to any section of the catalogue,
w-hether it be that concerned with X-Ray work, or apparatus
dealing with medical electrical currents, light, or high
frequency.

THE MICROSCOPE AND SOME HINTS ON HOW
TO USE IT.— Mr. E. Leit/i has issued a useful little
pamphlet under the title given in our side-heading. It should
be especially useful to beginners, as it describes the parts of a
microscope in detail and explains the terms such as aperture,
resolving power and so on, which are applied to it. There
are paragraphs on such topics as focussing, and the making of
measurements imder the microscope, while three pages are
devoted to general hints as to the treatment and care of
the instrmiK-nt.

NOTES.

ASTRONOMY.

By A. C. D. Crommelin, D.Sc.

DIAMETERS OF STARS.— The question of the diameters
of the stars is at once a most interesting and a most difficult one.
Both the late Mr. R. A. Proctor and Major Macmahon have
suggested using occultations of stars by the Moon for this
purpose, the former by putting the star image into rapid
rotation and noting the arc over which fading extended, the
latter by trying to record the disappearance on a photograph of
large scale. However, it is improbable that either of these
schemes is workable, and they would be limited to stars near
the Ecliptic. M. Charles Nordniann has attacked the problem
in another manner, {Coinptcs RcndKs dc VAcadcniw, 1911,
January 9th. I It is clear that the problem would be soluble if
we knew the distance of a star, its brightness compared with
the Sun's at an equal distance and the ratio of its surface
brightness to that of the Sun. The first datum is known with
tolerable accuracy for the nearer stars ; the second follows
from it; the third is the most difficult, but M. Nordmann has
given a formula for the " intrinsic effective brightness " based
on a study of the relative intensity of different positions of the
visible spectrum. (Thus it is generally admitted that the stars
with the Sirian type of spectrum have a greater surface
bj-illiance than those with the solar type, and still more than
those of a decided red colour). This is obviously the most
open to doubt of the assumptions, but we may take M.
Nordmann's list as giving at least a rough idea of the
dimensions of some of our stellar neighbours. He takes the
Sun's stellar magnitude as —26-83, which is the result of
recent Harvard measures and is in good accord with the
mean of the best previous results.

.Star.

Mag.

Assumed

Effective

Diameter

Parallax.

Temperature.

(Sliivs = i)

Sirius

-1-58

0-"37

12,200° (Cent.)

M3

Proczon

0-48

0-"30

6,810° „

1-35

.■\ldebaran ...

1-06

0-"15

3,500" ,,

13-50

Capella

0-21

0-"12

4,720 „

8-26

Vega

0-14

0-"12

12,200^ „

1-57

7 Cygni

2-32

0-"10

5,620° „

0-92

"■ Persei

1-90

0 • "08

8,300' „

1-83

Polaris

2- 12

0-"07

8,200° .,

1-93

^ .•\ndromedae

2-37

0-"07

3,700° „

13-0

/i Persei (.-Vlgol)

2-10

0-"05

13,800= ,.

1-29

It will be seen that Aldebaran and ji Andromedae are the
giants of the list, the result for the former being entitled to
more weight owing to the greater parallax. The above value
would make the apparent diameter of Aldebaran 0"- 01 8, which,
as M. Nordmann points out, would require an aperture of twenty
feet for its direct measurement, .\ direct occultation of this star
by the Moon would occupy one-thirtieth of a second, which might
be increased two or three times or even more, in an oblique
occultation. It will be seen that, according to the figures,
Aldebaran surpasses our Sun in size more than our Sun does
Jupiter. The likelihood that Sirius does not greatly surpass
the sun in size, in spite of its great brilliance, was already
inferred from the fact that its mass is only double his, so the
new value is quite reasonable. Arcturus. not included in this
list, is another great sun ; Miss Agnes Gierke said of it : —
" Perhaps the most stupendous orb within our imperfect
cognisance."

THE SYSTEM OF ALG( )L.— Algol, the last star on the list,
was the first to have its diameter measured by Vogel using the
spectroscopic method to find the rate of motion ; assuming the
densities of Algol and the companion to be equal, he found

1,051.000 miles for the diameter, or 1 • 2 of the -uui as a result,
independent of the parallax, and curiously close to that
independently found by M. Nordmann. A new and beautiful
investigation of this system has recently been published by
Mr. Joel Stebbins, of the University of Illinois, {Astrnphys
Joiini., October, 1910). He uses a selenium photometer
attached to a twelve-inch refractor. An out-of-focus image of
the star, seven millimetres in diameter, is thrown for ten
seconds on a selenium plate, which is in an electric circuit
forming one. arm of a Wheatstone bridge ; the galvanometer
deflection is measured, and corresponding readings taken on
a Persei and S Persei for comparison. The method is far more
sensitive than that of visual comparisons, and reveals (what
had long been \dsually sought in \'ain) a secondary minimum
when the companion is occulted by Algol, the depression
being 0-06 magnitude. He infers that, taking the parallax
0"-05, the side of the companion nearest .Algol gives six times
the light of the Sun, and the other side three times. The
difference is inferred from the fact that a continuous increase
in light is noted from principal minimum to secondary minimum,
and the probable explanation is the tremendous radiation
from Algol to which it is subjected. ( )n different assumptions
as to the distribution of density in the system, the estimates of
the diameter of Algol range from 0-81 to 1 -45 of the Sun. the
companion being one-seventh larger than the primary, and
the eclipses partial ; the apparent ellipse being about 8 open.
On all the hypotheses the surf.ace brilliancy of .■\lgol is much
greater and its density much less than those of the Sun.

Mr. Stebbins is to be congratulated on his successful appli-
cation of the selenium cell, which will doubtless in the future
be largely employed for measuring small light changes. The
idea is not new, but previous attempts have not met with
equal success. One necessary precaution is to enclose the cell
in an ice-box, its sensitiveness being greatly increased.

THE EIGHTH SATELLITE OF JUPITER.— This tiny
body will be out of reach at Greenwich for some years, while
Jupiter is south of the Equator: it is therefore a matter of
satisfaction that it was photographed during February with
the large reflector at Helwan in Egypt. The positions are
within some 20" of these predicted. The error can be
removed by increasing the adopted period (738-9 days) by
a quarter of a day, and making a very slight increase in the
eccentricity. This satellite will ultimately give a very accurate
mass of Jupiter, but it nuist be observed o\'er a larger arc
before it can be fully utilised for this purpose.

ADOPTION OF WESTERN E U R O P I-: A N
(GREENWICH) TIME IX FRANCE. — This adoption
took effect on March lOth, the date of the meeting of
the Royal Astronomical Society, who passed a resolution
authorising their President to despatch a telegram of
congratulation to the President of the French Republic. An
important advance is thus made towards the attainment of the
ideal universal time, the minutes to be the same everywhere,
while the hours change in each zone of 15° of longitude.

BOTANY.

By Professor F. Cavers, D.Sc, F.L.S.

SOME RECENT WORK ON GEOTROPISM.— Giltay
(Zeitschr. f. Botanik. 1910) has recently discussed and
criticised various methods of experimentation on the problems
of geotropism, and has called attention to a point which is often
overlooked by students of Vegetable Physiology, namely, that
we have never proved that gravitation is the only stimulus
in\-olved in the turning of the primary root towards the centre
of the earth. Long ago. Knight (1806) showed that as the
centrifugal force was increased on a centrifuge with a vertical
axis, the root and stem assumed a more nearly horizontal

147

14S

KNOWLEDGE.

April, 1911.

position, but he did not show any relation between the position
of stem and root and the resultant of the two forces involved —
gravity and centrifugal force ; that is. Knight showed that at
least in part the* so-called geotropic stimuhis is the gra\ity
stimuhis. but he did not show that the gravity stimulus is the
only stimulus involved. Giltay devised a special centrifuge in
order to test whether the position taicen up by the root and stem
is in reality the resultant of the two forces, andfound that this is
the case, with slight deviations that could be accounted for bv
variations in the speed of rotation and the variation of the roots
themselves. Hence it may be assumed that the geotropic
stimulus is identical in Nature with the gravity stimulus and
with that of centrifugal force.

Since ISSO, when the Darwins published (" Power of Move-
ment in Plants"') the results of their experiments on the
behaviour of decapitated roots, there has been a good deal
of controversy regarding the perceptive region of the root.
Czapek (Jahrb. xciss. Bot., 1895) caused the root-tip of seed-
lings to grow into a boot-shaped glass cap, and showed that
when the terminal portion (1.5 millimetres long) of the capped
root was placed horizontally, the portion outside of the " boot "
curved so as to bring the root-tip into the position of equili-
brium— the vertical position. On the other hand, if the seed-
ling was fixed so that the tip was vertical and the rest of the
root horizontal, no curvature took place, the root simply con-
tinuing to grow without changing the position of the tip or of
the elongating zone. These results were interpreted to mean
that only the apical one or two millimetres of the root was
sensitive to gravitation, and it was generally thought that
the matter had been finally settled. The simple experiment
of cutting off two millimetres of the root tip, though it
destroyed the sensitiveness of the root, had been objected
to on the ground that the wounding might have also
destroyed the sensitiveness of the elongating zone behind
the wound, but Czapek's ingenious experiment was regarded
as final, though Jost and a few other writers have steadily
maintained that the question is still open. Newconibe
[Bcili. Dot. Ccntralb., Band xxlv.. Abt. ;.), after
upholding these objections and pointing out that " neither
Czapek's nor any other method so far employed has or can
prove the restriction of the perceptive region to the apical two
millimetres of the root," proceeds to show (1) that all the
phenomena observed accord equally well with the view
that sensitiveness extends through the entire growing zone,
but becomes diminished from the apex backwards, or
the view that sensitiveness is uniform through the growing
zone, but the tendency to automatic curvature — autotropism —
is stronger in the hinder than in the apical region ; (2) experi-
ments on the centrifuge with decapitated roots show that
geotropic sensitiveness is present more than four millimetres
distant from the tip. It must be admitted, of course, that in
a question of this kind the same results may be interpreted in
diametrically opposite ways by different observers, but it
would certainly appear that we should keep an open mind on
the matter. Newcombe's paper is of importance as a
reminder that even the most fundamental questions relating
to reflex actions in plants are by no means settled yet, and
that much further work is necessary before it will be possible
to obtain a clear picture of what happens in the growing tip of
a root when it emerges from the seed and grows down into the
soil.

Another aspect of geotropism has just been re-in\estigated
by Nienburg {Flora, Band 102, 1911) in connection with the
movements of twining stems. Nienburg's work, like that of
Newcombe on the root, was done largely with centrifugal
apparatus, and he also has obtained results at \-ariance with
those of pre\'ious investigators. In 1881, it was shown by
Schwendener that the rotating movements of twiners like Hop
or Convolvulus, are not made by the stem when the plant is
kept revolving on a klinostat, and later it was suggested by
Noll that twining stems make a peculiar response to the
stimulus of gravitation, in that growth is promoted on
one flank, instead of on the upper side as in a root,
or the lower side as in an ordinary stem. This response
was termed " lateral geotropism," its result being a
revolving motion of the shoot apex. The clasping of supports

by tendrils, like those of Peas or Vines, is, of course, an
entirely different phenomenon, due to contact irritability.
From his experiments. Nienburg concludes that all the facts
observed in the growth of twining plants can be explained as
due to the combined action of autonomous rotation (nutation)
and ordinary negative geotropism. and that neither Noll's
experiments nor those of later writers have established the
existence of any such thing as " lateral geotropism." However,
it would appear that here again we ha\e an as yet unsettled
question, and one which requires further investigation
with the aid of klinostat, centrifuge, and other methods of
experimentation.

The curious "peg" or "heel" that grows out from the
seedling of Cucumber, Marrow, and other Cucurbitaceae, and
which holds down the seed-coat and helps the yoimg shoot to
escape, has been recently investigated carefully by Crocker,
Knight, and Roberts {Bof. Gaz., November, 1910). Accord-
ing to Francis Darwin, Cucurbit seedlings allowed to germinate
on a slowly-rotating klinostat produce pegs completely
surrounding the young shoot, and therefore appearing like a
collar, and he concluded that gravity determines the lateral
development of the peg, and that therefore this experiment
shows that gravity is continually effective on the klinostat and
is simply equalised in its action on the several flanks of the
rotated object : he also used the peg as a support for the
memory theory of plant response, assuming that its develop-
ment and position are directly determined by gravity. Crocker,
Knight, and Roberts, as the result of many experiments,
conclude that there is no evidence that gravity acts as a direct
stimulus to the lateral development of the peg, or that it leads
to increase in size of the peg ; that if the young shoot
(hypocotyl) is prevented from arching, the peg develops
equally all round ; that the lateral development of the peg is
simply brought about by the arching of the hypocotyl, the
most effective factor in this arching being the contact of the
seed-coat.

CITRIC FEKMl'NTATION.— Since Wehmer in 1893
described the process of citric fermentation and showed that it
is due to a mould-like fungus, Ciiromyccs. several workers
have dealt with the subject, and Wehmer has recently given
a critical summary of their papers and of his own further
researches on citric acid fermentation, and the Citromycctes
\Zcitschr. f. Bot., Heft 2, 1911). The process is evidently
in the main one of oxidation of sugar — especially of malt, cane,
and grape sugars — and under favourable circumstances as
much as fifty per cent, of the sugar may be converted into
citric acid. The three sugars named yield the largest pro-
portion of the acid when acted on by the fungus, but a fair
yield is obtained from glycerine (nearly thirty per cent.), and
much smaller quantities or merely traces from various sugars,
inulin, alcohols. Up to the present it is doubtful whether the
action is caused by an enzyme produced by the fungus, for
negative results have been obtained with expressed sap and
with killed fungus. Many interesting questions I'egarding the
mode of action of the citric acid fungus arise from recent
investigations. It has been suggested that since acid is
formed, though sparingly, in the absence of free oxygen, the
first step in the action must be the splitting of the sugar
into carbon dioxide and alcohol — as in alcoholic fermentation.
The alcohol would then be oxidised with the production of
citric acid, this second action or citric fermentation proper
corresponding with the analogous processes of lactic and acetic
fermentation.

R1:CI-:NT work on the GNFTALES.— The remark-
able group Gnetales includes the three genera Gnctiiin,
Ephedra and Welicitschia. which differ from all other Gymno-
sperms in having compound inflorescences, a long micropylar
tube, and true vessels, and which make a further approach to the
Angiosperms in the fact that except in Ephedra the archegonia
are reduced to isolated cells. Various writers have suggested
that the Gnetales form a transitional group between Gymno-
sperms and Angiosperms, though it seems more likely that they
had a common ancestry with the Angiosperms, and developed
parallel with them. Porsch (Ber. deutsch. bot. Ges., 1910)

Aprh, 1911.

KNOWLEDGE.

149

has shewn that Ephedra cainpylopoda. found in the south of
Europe, is not only adapted for msect-pollination, but is
regularly \isited by insects. In his intei-esting memoir on
this the first established case of insect pollination among the
Gymnospernis. Forsch shows that the yellowish-red colour of the
inflorescences attracts insects, which feed on the sticky pollen,
and that nectar is provided in the form of drops which ooze
from the micropj-le. The insect-visitors included thirteen
species of Hymenoptera and Diptera, which were found to
carry the pollen on the underside of their bodies. Since
secretion of sugary liquid occurs in the flowers of Gncttiin
and Wcht'itschia, it is very likely that these genera also
are insect-polhnated, though, until now, it has been supposed
that the function of the liquid which oozes from the
micropyle, is simply that of catching pollen blown by the
wind, in much the same way as in the female cones of pines.
Pearson {Phil. Trans. Roy. Soc, 1909) had already suggested
that the flowers of Wclicifschia are insect-pollinated, and in
this plant there are glandular outgrowths below the anthers
which doubtless act as honey-glands. Pearson has also
described, though not fully, the development of the ovule of
this remarkable genus. The endosperm begins, as usual, in
Gymnospernis. with free nuclear division, forming an embryo-
.sac with appro.ximately one thousand and twenty-four free
nuclei, representing ten successive divisions. These nuclei
are distributed through the sac, so that when cell-walls are
formed the sac is divided into multinucleate cells ; those in
the micropylar (upper) region contain fewer nuclei than the
others, and they become the nuclei of free eg.gs. The cells of
the lower three-fourths of the endosperm contain many nuclei,
and these fuse and form a uninucleate tissue — the primary
endosperm, which continues to grow both before and after
fertilisation. The multinucleate cells of the micropylar region
send out tubes into the overlying nucellar tissue, into which
the free nuclei pass, and these prothallial tubes meet the
pollen-tubes in the lower half of the nucellar cap.

CHEMISTRY.

By C. .AiNswoRTH Mitchell. R..\. (C_).\on.). F.I.C.

COMBUSTION OF G.'\SES WITHOUT FLAME.— .\
new property of copper is described by M. J. Meunier in the
Coinptcs Rcndiis (1911, clii. 194). On heating a wire of pure
copper in the luminous flame of a Bunsen burner until all sur-
face oxide has been reduced to metallic copper, and then
admitting air the wire will begin to glow. On now lowering
the hot copper into the tube of the burner, the steady glow
will continue without igniting the mixture of air and gas in the
tube. The maximum intensity of glow is obtained when the
proportion of gas in the mixture is about 30 per cent. During
this slow combustion the copper is rendered exceedingly brittle
and may readily be reduced to a powder of crystalline
appearance.

CELTIUM: A NEW ELEMENT.— M. G. Urbain des-
cribes in the Comptcs Rcndits (1911, clii. 141). a new element
for which he suggests the name Ccltinin and the symbol Ct.
It was found accompanying the elements lutecium and
scandium in gadolinite earth, and was isolated from the mother
liquor obtained in the separation of lutecium. In its .general
properties it is intermediate between these two metals, and
differs from both in its magnetic permeability and in its
spectrum. Its chloride is more volatile than that of lutecium,
but less volatile than that of scandium, while its hydroxide is
a stronger base than scandium hydroxide, but is weaker than
lutecium hydroxide. Its atomic weight has not yet been
determined.

HELIUM IN THE AIR OF VESUVIUS.— In the only
recently published proceedings of Section II of the Seventh
International Congress of Applied Chemistry of 1909 (pages
83-86). Mr. A. Piutti gives an account of his investigation
of different incrustations from Vesuvius which at various
periods he has tested for helium. In each case the substance
was heated and the gas emitted was absorbed by cooled
charcoal. A specimen of sanidinite from Vesuvius yielded

0-106 c.c. of gas per granmie. Its radio-activity was found
to be principally due to the presence of zircon crystals, and
these, like the gas, contained helium.

In like manner a specimen of pink tourmaline, which yielded
0-511 c.c. of gas per gramme was found to contain helium, and
this element was also identified in the air of Naples as well as
of \'esuvius.

Its presence was also proved in the zircons from many other
localities, and in the case of large tourmalines from
Madagascar the green outer portion was more radioactive and
contained more heHum than the inner light pink part. In
general, though not invariably so, the proportion of helium
corresponded with the degree of radio-activity.

SPONTANEOUS IGNITION OF COAL.— The results
of a bacteriological investigation of the spontaneous com-
bustion of coal, by Mr. E. Galle, an outline of which is
given in the Cheiii. Zcntralhl. (1911, I. 48), have suggested
several interesting conclusions. Cultivations were made both
in the presence and absence of air, and seven species of
bacteria were isolated from coal. Of these, four species
{B. nacraceus, B. siibtilis. B. mcscntcricus. and
B. pseudosuhtiUs\ were found to be capable, when grown
on suitable nutrient media in the presence of coal dust, of
producing combustible mixtures of gas containing from 5-4 to
27-3 per cent, of carbon dioxide, and 71-5 to 84-8 per cent,
of methane, together with traces (less than three per cent.) of
carbon monoxide, oxygen, and hea\-y hydrocarbons. Onlv
B. nacraceus and B. pseudosuhtilis produced these latter
gases. The conditions under which these mixtures of com-
bustible gases were produced were perfectly comparable with
those that would occur in nature, and there is therefore every
reason for assuming the possibility of their production by
bacteria in coal measures.

Hence, while the spontaneous ignition of coal cannot be
.attributed exclusively to bacteriological activity, it is not
improbable that bacteria may be an important factor in its
occurrence.

FIRE-PROOF AND SUBMARINE PAINTS.— .An
abstract of a paper read before the Seventh International
Congress of Applied Chemistry of 1909, by M. Coflignier, is
published in the Jonrn. Soc. Cheni. Ind. (1911, xxx., 223).
In fire-proof paints the principle adopted is to incorporate
with the other ingredients of the paint an ammonium salt, which
under the influence of heat, will give oft' ammonia, and so
produce an atmosphere unfavourable for combustion. The
solubility of most ammonium salts renders them unsuitable for
this purpose, but good results have been obtained by mixing
the pigment with insoluble ammonium magnesium phosphate
and a special medium consisting of linoleate of lead in oil of
turpentine.

In 1895. a special submarine paint was prepared by
Holzapfel, the object being first coated with an anti-corrosive
deposit, and then with a second layer containing toxic
substances. Owing to the reactions which occurred between
the two layers, however, the paints were liable to crack, and
would not last for more than about six months.

Recently this drawback has been remedied by the production
of a paint in which the outer coating consists of an amalgam
of copper incorporated with an earthy pigment and a water-
proof medium.

.As soon as marine organisms attack this coat the amalgam
is exposed, and voltaic currents are produced which set free
poisonous compounds of copper and mercury and destroy the
intruders. Thus the action is only brought about in places
where it is necessary, and the life of the paint is doubled.

GEOLOGY.

By Russell F. Gwinnell, B.Sc, A.R.C.S., F.G.S.

THE GEOLOGICAL SURVEY OF SCOTLAND.— Three

colour-printed sheets of the one-inch map of Scotland have
recently been issued, together with memoirs on the same districts.
Two of these (Edinburgh and Haddington) are new editions ;
the third is the long-exptcted Glenelg sheet, which includes

150

KNOWLEDGE.

Aprii., 1911.

the eastern half of the Isle of Skye. This Glenelj,' sheet, in
particular, is a splendid example of colour-printing. Nearly
sixty different ghades of colour (including hatched and
stippled patterns) are used, and a lartjc number of dykes and
sills are mapped, so that altogether the map is very complicated :
but nevertheless the use of colour-printing has made it
possible to issue the sheet at the low price of half-a-crown.
The issue of this sheet and memoir is opportune, as the
Geologists' Association (of London) will be visiting the district
this coming summer, under the guidance of one of the Survey
officers, Mr. .\lfred Harker. M.A., F.R.S., whose work on the
Tertiary Igneous Rocks of Skye is so justly celebrated.

The ancient Lewisian and Moine rocks of the Glenelg area
are dealt with in detail in the memoir and some interesting
lithological types described, such as the brilliantly-coloured
eclogites and garnet-amphibolites, with a garnet-fuchsite rock
(containing the vivid green chrome-mica, fuchsite). Lewisian
limestones occur containing various silicates, especially
diopside, which sometimes forms masses up to several yards
across, also abundant forsterite crystals and great poikilitic
plates of phlogopite enclosing grains of calcite. As to the
puzzling Moine schists some evidence appears to indicate
that these were laid down iiiiconforiuably on the Lewisian
gneiss, and, while no definite conclusion is reached, various
facts suggest that they may be altered representatives of
Torridonian sediments.

A large relief-model of Central Skye has been constructed,
which brings in most of the western half of this Glenelg sheet.
There are copies of this model at the Survey Museum (Jennyn
Street), at tlie Science Museum (South Kensington), at the
coming Coronation Exhibition, and elsewhere.

The memoir on " The Geology of the Neighbourhood of
Edinburgh " was first published in 1S61. The new edition, the
second, forms a valuable guide to this interesting district. The
main geological interest lies, perhaps, in the igneous rocks, and
the petrography of these forms an important part of the
volume. Noteworthy are the numerous highly-alkaline types,
often containing analcite, as, for example, the associated
Essexites, Tesehenitesand Picrites, as well as Mugearite. This
last peculiar type, first described by Harker from the Tertiary
Series in Skye, and recorded in this memoir from the
Carboniferous of Edinburgh, has also been found in the
neighbourhood of Glasgow, while within the last few weeks
Mr. H. H. Thomas has proved its occurrence in the
Ordovician volcanic series of Skomer Island. Pembrokeshire
(Abstract of the Proceedings of the Geological Society.
February 1st, 1911). The main peculiarity of this type lies
in the paragenesis of olivine with such alkaline felspars as
oligoclase and even orthoclase.

The structure and age of the old volcano of .Arthur's Seat.
Edinburgh, has long been a subject of contention. On the
one hand MacLaren, over seventy years ago, maintained that
it represented two entirely distinct series of volcanic outbursts,
separated by a vast interval of time, the older being of Lower
Carboniferous age. This interval was marked by the
deposition, subsequent upheaval and removal by denudation
of at least three thousand feet of Carboniferous strata. In the
first edition of the present memoir, Geikie followed this view
and considered the supposed younger volcanic series to be
probably of Tertiary age, but later he referred them to the
Mesozoic, and then to the Permian. Professor Judd. in 1875.
advocated the theory that the supposed second series of
volcanic outbursts had no existence, but that all the rocks are
the result of a single and almost continuous series of eruptions
confined to the Lower Carboniferous period. The evidence
obtained during the recent revision of Arthur's Seat by the
Geological Survey has confirmed Professor Judd's contention.

ORIGINAL GNEISSOSE BANDING.— The term
" gneiss " covers a multitude of rocks, which differ vastly
not only in composition, but in mode of origin. Their only
community lies in the possession of that foliated character
known as the gneissose structure. Some have been derived
from sedimentary rocks (the paragnciss of Rosenbusch,
epigneiss of Reusch and mctagneiss of Lepsius) ; others are
of igneous origin iorthogneiss of Rosenbusch), while in others

Hhi2 protogneiss of Lepsius) some see the primary crust of tlie
earth. Vet another type, the adergnciss of Sederholm, is both
igneous and sedimentary in origin, the foliation being the
result of the injection of many veins of pegmatite into a
sedimentary rock, so that the sediment becomes thoroughly
permeated by igneous material. This type is described among
the Lewisian rocks of tlie Glenelg area in the memoir already
referred to in these columns.

But confining our attention to orthogneisses only, we find
several distinct types, of which the most usual has — at any
rate in the past — been regarded as due to regional meta-
morphism. Professor G. H. \Villiams was one of the early
exponents of the school which laid great stress on this mode
of origin. .Another possible means of producing foliation in
igneous rocks (of plutonic type) is by successive intrusions of
magma of different composition into the same consolidation
site. Thus Harker accounts for the coarser banding of tlie
peridotites of Rum in the Inner Hebrides. There remain two
very similar methods, the intrusion of one molten mass already
heterogeneous and the simultaneous intrusion of two different
magmas. The finer banding of the Rum peridotites and the
foliation of gabbro in the Cnillin Hills, Skye. have been
explained in this manner, as well as a perfect banding in the
dioritic complex of the Island of Orno. near Stockholm.

The foliation in the Cortlandt Series — an igneous complex
ranging from granite through syenite, monzonite, diorite,
gabbro and norite to p^'roxenite and peridotite, occurring
about thirty-five miles north of New York City — has been
dealt with by several authorities. Professor J. D. Dana
regarded the rocks as worked-o%er sediments, \'olcanic ashes or
tuffs which, on being subjected to intense local inetamorphism,
lost most of their bedded structure and became pseudo-massi\ e;
later he treated them no longer as paragneisses but as of
igneous origin (orthogneisses), and Dr. G. H. Williams, in 1S86.
regarded the foliation as due to regional metamorphism. In
Tlie American Journal of Science for February, 1911,
G. S. Rogers demonstrates the origin of these rocks (where
norite and pyroxenite form alternate layers of constant grain)
to be by " magmatic differentiation. " as in the cases of the
Rum peridotites and the Skye gabbros.

Up to the present this original gneissoid banding has not
been recognized in many localities ; it may, however, prove
illuminating (especialh' if found to be more common than is at
present thought) in connection with some of the puzzling
structures of the ancient and obscure igneous gneisses.

THE HARDNESS OF MINERALS.— In spite of all
criticisms Mohs' scale of hardness still holds its place as the
standard of reference in Mineralogy. Breithaupt interpolated
two extra minerals between numbers 2 and 3 and 5 and 6
respectively, converting Mohs' scale of ten minerals into a scale
of twehe, in the attempt to make the intervals between
successive numbers more uniform. By various methods of
estimating "absolute hardness," Pfaft', Jaggar and others,
shewed that the intervals are far from uniform, and thus the
series of figures representing absolute hardness form a
progression which does not approximate either to arithmetical
or geometrical progression. But most noteworthy are Rosiwal's
figures, obtained in 1892, which show that Topaz (number 8
in Mohs' scale, where 1, the softest, is Talc, and 10, the
hardest, is Diamond) is softer than Quartz (number 7). Thus
in detail inversion of the correct order is indicated.

Rosiwal obtained his figures by using a standard abrasive
to grind the mineral surface, and determining the loss of
weight suffered by the mineral when a given weight of the
abrasive was used up. In The American Journal of Science,
February, 1911, H. Z. Kip describes how he obtained a
similar result by a different method, which depends on the
force required to produce abrasion on the mineral, by a
diamond-point sclerometer.

■■ Pfaff, Jaggar and others who .arrive at the opposite con-
clusion, have failed to eliminate the factor of density in
carrying out their tests. In other words, while regarding
hardness as resistance to abrasion, they have sought to
determine its value on the theory that it was to be measured
in terms of resistance to excavation."

Ai'lui.. 1911.

KNOWLEDGE.

151

METEOROLOGY.

B.v JoHX A. Curtis, F.R.Met.Soc.

IHl-: WEATHER of the week ending Febrnary Itith
as detailed in the Weekly Wcatlier Report issned
by the meteorological office, was very warm for the
time of year, with heavy rain in Scotland and Ireland
and the Northern Counties of England, and moderate
to scanty sunshine. The excess of temperature \aried
from 5" -6 in Scotland E., to 0"-6 in the English
Channel. The maxima were above 50' at nearly every
station, and reached 59' at Aberdeen on the 16th, and at
Bawtry on the ISth. At Guernsey, however, the highest
reading was only 51 . The nights were cold, and the
minimum fell to 18° at Balmoral on the 12th, and to 21" at
Cirencester and Swarraton on the same day. On the grass
the temperature fell to 10 ' at Llangammarch Wells, and to
12" at Newton Rigg.

Rainfall was frequent and heavy in the North. .At
Glencarron it rained every day, and the total for the week
was 6-94 inches; at Fort William 5-39 inches were collected.
At Westminster the total was only 0-25 inch in three days.

Sunshine varied a good deal in different parts. At Newquay
the total duration was only 7-0 hours, as compared with an
average of 19-4 hours, while at Eastbourne it was 29-7 hours,
or 11-3 hours above the average.

The mean temperature of the sea w-ater varied from 47° -5
at Scilly to 38°- 1 at Cromarty.

The weather of the week ended February 25th was very
changeable. There was a good deal of rain, but bright
intervals were common. Snow was plentiful in parts of
Scotland, where also thunderstorms were experienced.
.Aurora was seen on several nights during the week.

Temperature was still unusually high in all parts. The
highest reading was 59' at Dublin on the 21st, but readings
of 58° were reported at several stations from Leith to Fulbeck
(Lincoln) and Birr Castle. The lowest readings reported were
21 ' at Sunburgh Head and Balmoral. At Guernsey, however,
while the maximum did not exceed 52', the mininuun did not
fall below 40°, a range of 12", as compared with a range of 28°
at Sunburgh Head (49° to 21'). The lowest readings on the
grass were 15' at Llangammarch Wells and 16 at Crathes.

Rainfall was in excess in all Districts except the English
Channel, where it was just below the normal. In some places
very heavy amounts were collected — thus at Glencarron the
total was 5-01 inches, and at Fort William 5-60 inches.
Including the amounts collected in the previous week the
totals at these two stations for the fortnight were 11-95 inches
and 10-99 inches respectively, or 8-39 inches and 7-45
inches, above the averages for the same period. In spite of
the generally heavy rain sunshine was abundant in all districts.
Dublin was the sunniest station with 36-9 hours (53%) but
many stations reported upwards of 45%, Ventnor 47% and
Torquay 48%. In Westminster the total duration was 24-5
hours or 35%. The temperature of the sea water \ariedfrom
49° -47° at Scilly to 39" -34= at Cromarty.

The week ended March 4th proved to be unsettled, with
frequent rains. Aurora was seen in Scotland on the night of
February 28th. Temperature continued above the average in
all districts, the excess amounting to as much as 6" -7 in the
Midlands, where 60 ' was reported as the maximum at Raunds,
on March 2nd ; 60° was also reported at Westminster on the
same day. The maximum for the week at Jersey was 53° on
the 3rd, on which day Strathpeffer reported 54°. The lowest
minimum was 22° at Balmoral on the 27th. In Ireland and in
the South of England no frost was experienced during the
week. On the grass minima down to 19 were observed.

Rainfall was also in excess, except in England N.E. In
England N.W. and S.W. the total for the week was double
the average, but individual heavy falls were rare. Sunshine
varied in different districts. In Scotland E. it was 11 hours
(16%) in excess of the average, while in the Channel Islands
it was 5 hours (6°;,) in defect. Crathes I'eported the most
sunshine, 36-7 hours or 51%. .4t Westminster the duration
was 18-3 hours, 25%. The temperature of the sea water
varied from 51° at Seafield to 33° at Wick.

The weekended March 11th, was cooler and drier than those
that had preceded it. Temperature was, however, still above
the average in many places, though not to any great extent.
In the South it was slightly in defect. The maximum for the
week was 57° at Killarney, on the 8th, but at no other station
in the British Isles was a reading higher than 52° reported.
In many places the maximum was below 50\ Frost was
experienced in all Districts except the English Channel, the
lowest readings being 24° at Balmoral, and 25° at
Fort Augustus and Llangammarch Wells. On the grass the
temperature fell to 13° at Llanganunarch, and to 20° at Kew
and Tunbridge Wells.

Rainfall was variable. It was heavy in Scotland N. and in
the South of England and Ireland, but not far from the
normal in other parts, generally slightly below.

Sunshine as a rule was above the average, and the District
percentages ranged from 46% in Scotland E. to 24% in the
Midland Counties. The sunniest station was Gordon Castle,
40-5 hours or 53%. Westminster reported 10-4 hours or
13%.

The mean sea temperature was 47-4 at Scilly and 38° -5 at
Cromarty.

UPPER AIR RESULTS.— On February 14th, a kite at
Pyrton Hill, when three thousand six hundred feet above the
ground, entered a current of air, which, though moving in
nearly the same direction, was 9° F. warmer and much drier,
and had a velocity of 50% greater than that immediately
beneath it.

On the 16th, at Brighton, a kite sent up by Mr. S. H. R.
Salmon entered the clouds at only three hundred feet above
the ground, and became unmanageable owing to the great
increase in wind velocity.

ANCIENT RAINGAUGES.— It has generally been
accepted that the first raingauge of which we have record was
made by an Italian, Benedetto Castelli, a contemporary of
Galileo, in 1639, but Dr. Y. Wada, the Director of the Korean
Meteorological Observatory at Chemulpo, has given in the
"Scientific Memoirs of the Korean Meteorological Observatory,"
Vol. I., an interesting account of the installation of a number
of raingauges and the organization of a system of rainfall
observation in the year A.D. 1442, or one hundred and ninety-
seven years before Castelli. The account, which has been
unearthed from the Korean historical records, tells how " King
Sejo caused an instrument of bronze to be constructed to
measure the rain. This is a vase fifteen inches deep and
seven inches in diameter, placed on a pillar. The instrument
has been placed at the Observatory, and each time rain falls
the Officials of the Observatory measure the height with a
measure and make it known to the King. These instruments
were distributed to the Provinces and Cantons, and the results
of the observations were sent to the Court."

MICROSCOPY.

By A. W. Sheppard, F.R.M.S.,
icitli the assistance of the folloicung iiticroscopists : —

AlClHLK C. P.ANKIKLU. ARTHUR EaRLAND, F.R.M.S.

[AMES r.uRTON. RicHARu T. Lewis. F.R.M.S.

The Rev. E. \V. B.iwELl,, M.A. Chas. F. Rol'SSELet, F.R.M.S,

Charles H. Caffvn. D. I. Scolrkield, F.Z.S., F.R.M.S.

C. D. Soar, F.R.M.,S.

TRANSMISSION OF FLAGELL.-\TES IN FRESH-
WATER FISHES.— At the meeting of the Royal Society
held on February 23rd, Miss M. Robinson, M.A., read a
paper on the above subject, of which the following is an
abstract.

The goldfish in a pond at Elstree have for some years shown
an infection of trypanosomes in their blood. Quite recently
tr\-panoplasma has also appeared. Upon investigation it was
found that the leech Hemiclcpsis iiiarginata occurred in the
pond and effected the transmission of the parasites.

A large number of these leeches were obtained from the
Grand Junction Canal reservoir, which is only a short distance
from the pond. The young of these were hatched out in
captivity, and it was ascertained that the flagellates are not

152

KNOWLEDGE.

Apru,, 1911.

passed from parent to offspring. The parent leeches were
invariably infected with tr\-panosonies derived from the fish in
the reser\oir, wtrich frequentl\' showed these parasites in their
blood.

The trypanosomes of perch, bream and goldfish were fonnd
to complete their cycle in Hciiiiclcpsis. and conld be
transmitted to clean goldfish by means of leeches. The
specimens used in these experiments were always j'oung
laboratory-hatched Hciiiiclcpsis. The trypanosomes of pike
and rudd also complete their cycle in this leech, but the
opportunity of passing these two forms into goldfish did not
present itself. The cycles of the trypanosomes derived from
these different sources are apparently identical. Thr main
features are as follows : —

The trypanosomes taken into the crop of the leech along
with the blood multiply very rapidly, undergoing a marked
change of form. After some days slender forms begin to
arise. These increase in number, and at the end of digestion,
some time after the blood has quite disappeared, they come
forward and lie in the proboscis-sheath in very large numbers.
The form found in the sheath is a very slender, long creature
of quite definite type : division has never been obser\ ed in
this phase.

When the leech feeds once more, these individuals are
inoculated into the fish. The proboscis-sheath is always
cleared of trypanosomes by one feed. After a clean feed the
slender inoculative type of trypanosome disappears from the
crop of an infected leech, and the infection is carried on b\-
short, broad forms. Conjugation has never been observed.

If water is added to the blood of fish containing trypano-
somes. the flagellates divide after a number of hours, probably
in response to lowering of osmotic pressure in the fluid in
which they find themselves.

KOVAL MICROSCOPICAL SOCIETY.— Februarv 13th.
lyll, Mr. H. G. PHmmer. F.R.S., President, in the chair.
— Messrs. E. Heron - Allen and Arthur Earland read a
paper illustrated by a series of lantern slides on new or rare
species of Foraminifera found in the shore-sands of Selsey
Bill, Sussex. The authors called attention to the identity of
the fossil Foraminifera of the Bracklesham Beds with the
living species found in Australian shore-sands. Recent
specimens of Bolivina diirrandii Millett and PnJvinuliita
vcnniciilata Brady, were shewn, the only other known records
being as regards the former from the Malay Archipelago, and
as regards the latter from tropical and sub-tropical seas. In
addition to these, Milioliiia suborhiciihiris. M. rotunda,
Tcxtuhtria inconspicna. var jugosa, Bolivina turtnosa,
Uvigcriiia aspcnila, and Sagraina diinorplia, were recorded
as new to Britain. Schlnmberayer's unique genus and species,
Hindci-ina briigesii, was recorded from the Eocene clays.
Also the first fossil records of Biilimina snbtercs and
Discorbitia polystoinclloidcs. Tlie new species recorded
were Piilviniilina haliotidca H. .\. and E., and Xonionina
quadriloculafa, H.A. and E. Specimens of these were
exhibited under microscopes during the meeting.

Mr. Lees Curties described a new dark-ground illuminator
which he had made to the instructions of .Mr. l-~. AL Nelson,
and which was so constructed as to work with slips ranging
from 0-8 to 1-2 millimetres in thickness, and which gave a
perfectly dark field with a Zeiss apochromatic four millimetres
lens of 0-95 N.A. The illuminator was provided with a fixed
central stop, and also with a slot for utilising the apparatus as
an oblique illuminator. A small dot placed on the front lens
served for the purpose of centring the condenser to the
optical axis.

SOME WORKS REFERRING TO RED-SNOW.— Mr.
James Murray has kindly prepared the following short
bibliography on the subject of his paper (see " Knowledge."
page 109) ; it will be of use to those readers who are desirous
of carrying fuither the subject of " Red-Snow " and its
occurrence.

Agardh. — Systcina Algariiin. \S1\.
.'\ristoteles. — Historia An iiiuiliiiin. V. \Z.

Charcot. — Rapports prcHininaircs siir Ics Travaiix executes
dans i'Aiitarctiqiic. .^cad. des Sci. Page 76. Paris,
1910.

Chladni.— Fi-xtT Mcfeorc. Pages 359-390. 1S19.

Darwin, C. — Journal of Researches. Page 311. London,
1845.

Ehrenberg, C. G. — .Mikr. Lebcn d. Alpeii n. Gletscher d.
Schweiz. Ber. X'erh. K. Akad. Berl. 1849.

Hooker, J. D. — Himalayan Journals.

Kerner and OUver. — TIic Xatiiral History o/ Plants. WA.
I. Pages 38. 54_'. Vol.11. Pages 627-631. etc. 1895.

Lagerheim. G. de. — Die Sclineetiora des Pichincha. Bcr.
" dcutsch. Bot. Ges. X. Pages 517-534. 1892.

Murray. J. — .Antarctic Rotifera : Brit. .Antarct. Exped..

1907-9. Sci. Reports. Vol 1. Page 41. 1910.
Ross. Sir John. — Voyafie of Discovery, for the purpose of

exploring Baffin's Bay. 1819.
Schmarda, L. — Klcine Beitrdge ziir Xaturgeschichte der

Infusoricn. Wien. 1846.
Shutllcwortli. R. J. — I. a inatiire coloraiite de la Seige

Rouge. Bibl. L'iii\. de Geneve. T Is. Pa,L;e 383.

1840.
Vogt, C. — Xotiee siir les .-\ni nuilciiles de la Xeige Rouge.

Bibl. Univ. de (iencve. Pages 80-86, April. 1841.

(JUEKETT MICROSCOPICAL CLUB.— Febnwry 28th,
1911. — Mr. D. J. Scourfield, V.Z.S.. F.R.M.S.. Vice-President,
haxing taken the chair, the President delivered his annual
address dealing this year with " Some Problems of F^ volution
in the Simplest Forms of Life."

Taking, first, the visible world of living creatures, no deep
reflection or analysis is required to grasp the fact that it does
not constitute a chaos of isolated and unconnected forms, but
is capable of being classified into greater or lesser categories.
The first and most obvious division is into animals and plants.

But between the categories of greatest and least extent there
are a number of intervening divisions, with regard to which
the scientific and the non-scientific public are hopelessly at
variance. The same is inevitably true in any branch of
knowledge dealing with a variety of concrete objects, simply
because the mind devoted to the study of any particular
set of things, animate or inanimate, soon becomes perforce
acquainted with so many more than ever come within the ken
of the casual observer, that in order to arrange them in an
orderly and intelligible system of classification, it is necessary
to draw distinctions and institute comparisons which are never
dreamt of in the philosophy of the mind occupied with other
pursuits.

Professor Minchin tlicn proceeded to review various systems
of classification popularly recognised, as, for instance, the
separation of \ertebrates into two main groups, one with
paired limbs, as in fishes, and the other in which the paired
limbs are pentadactyle in type. Then, again, animals may be
divided by their habitat into terrestrial, aquatic and aerial.
But to all these systems we at once find exceptions. Many
perfectly logical classifications are possible, but only one that
is perfectly natural, and that one, very often, is not perfectly
logical. It is now abundantly clear that natural groups can
seldom, if ever, be defined by precise and rigorous verbal
definitions. All that can be done is to construct for each
group a more or less ideal and imaginary type of organism,
possessing certain characters, none of which must be regarded
as fixed or invariable. If we must have verbal definitions of
groups, then logic requires the insertion of the word
"typically" before each character ascribed to them.

In dealing with the Protista, the President considered
that there are two well-marked types recognisable in these
organisms, one more primitive and older in evolution, the other
higher, and leading on to the ordinary plants and animals.
The difference between these two types depends on the con-
dition under which that peculiar substance occurs for which
we may use, in quite a general sense, the term chromatin. In
every cell of animal or plant,' and probably in e\erj- Protist

April, 1911.

KNOWLEDGE.

153

organism, there is found a certain amount of a substance
remarkable for its affinity for certain colouring matters, and
still more remarkable for the part it plays in all vital processes.
From the first of these characteristics the name chromatin has
been given to it. It is a substance, or combination of
substances, of a very high degree of chemical complexity,
perhaps more complex than any other substance, but it is by
no means of uniform chemical composition. The term
chromatin implies, in short, a biological or physiological, but
not a chemical, unity.

In the lower type of Prutist organisation, which is exem-
plified by the ordinary Bacteria, the chromatin is present in the
form of scattered granules — "chromidia." In the second type
a certain amount of the chromatin may still be present in the
scattered chromidial condition ; but the greater part, and in most
cases all of the chromatin, is aggregated into a compact mass,
the nucleus, and. apart from this nucleus, the remainder of the
living body is made up of a distinct protoplasmic zone — the
cytoplasm, scarcely recognisable in the bacterial type. With
difterentiation of nucleus and cytoplasm, the organism becomes
a "cell." This type will be termed the "cellular grade."
Reference was then made to
the existence in all forms of

higher life of sex and sexual N^

differentiation, and even in
the Protista we find sexual
phenomena to be of uni-
versal occurrence in the
cellular grade, but quite
absent in the organisms of
the bacterial grade. Much
has been written, and many
theories put forward, to '^»v^

explain the origin and sig-
nificance of sex. Professor
Minchin dealt briefly with

only one, that put forward by Doflein. and founded
by him on those enunciated previously by Hertwig
and Schaudinn. This theory is, shortly, as follows : — Living
cells are regarded as consisting of two groups of vitally active
substances, the one regulating motor, the other trophic,
functions. In cell-reproduction by fission, these substances
are never distributed with mathematical equality amongst the
descendants ; hence continued reproduction of this kind brings
about accumulations of different properties in certain
individuals, with, as a consequence, impaired vital activity and
reproductive power. Individuals are produced, some of which
are richer in stored-up nutriment (female), others in motile
substance (male). Since these two kinds of individuals contain
aggregations of substances which have intense nmtual chemical
reactions, they exert an attraction one towards the other ; the
two individuals tend to unite, and by their union cell-equilibrium
is restored and vital powers renewed. Hence syngamy is
regarded as a necessity for the life-cycle, due primarily to the
imperfections of cell-division and to the consequent loss of
equilibrium in the cell-constituents. On this view, the general
absence of sex phenomena in the lowest grade, and its existence
in the higher, is readily intelligible. In the bacterial grade, the
body, usually very minute, is of extremely simple structure.
In such organisms, inequalities of cell-division, if they occur,
can be adjusted easily by the rearrangement of the chromatin
substance. On the other hand, with the evolution of the
cellular grade, the body is differentiated into at least two parts,
nucleus and cytoplasm, and becomes of increasingly complex
structure. Consequently, an exact quantitative and ijualitative
partition of the body during cell-division is of extremely im-
probable occurrence — at least, until the mechanism of cell-
division has reached its greatest perfection. The fact that in
the Infusoria, the most complex in structure of all the Protista,
syngamy is a frequent event and easy to observe, fits in also
with the view that sex phenomena are in relation to complica-
tion of cell structure ; and, conversely, the fact that in
Protozoa of simple structure, such as the Flagellata, syngamy
is rarer, and appears only to occur at long intervals in the Ufe-
cycle, also receives a simple explanation. From all these facts

Figure 1.
and

and considerations, it appears extremely probable that sex and
syngamy were "invented" when the cellular grade was evolved
from the b.acterial grade of structure. This, again, the speaker
said, is related to another very important property of living
things — the more or less easy divisibility into groups which we
now term species. No one now considers a species as a fixed
and immutable entity. Nevertheless, the fact remains that
the tendency of living things to separate themselves into species
more or less distinct is one of the most constant and universal
pecularities of the organic world.

From these consider.ations it is evident that the passage
from the bacterial to the cellular grade was, perhaps, the most
important advance in the evolution of living beings. The
acquisition of the cellular type of structure was the starting-
point for the evolution, not only of the higher groups of the
Protista, but. through them, of the whole visible everyday world
of animals and plants, in all of which the cell is the unit of
structure, and which consists primarily of aggregates of cells.
Further.with the cellular type of structure were initiated, in the
speaker's opinion, two of the most universal and characteristic
peculiarities of living beings — namely, the phenomena of sex

and the tendency to form

species.

AN INTERESTING
MICRO -OBJECT FROM
A SINGULAR SOURCE.
— The fungus known popu-
larly as the truffle, and used
as a flavouring, affords some
interesting and instructi%e
microscopical objects. At
the same time it is not
exactly easy to obtain,
and it occurred to me
to resort to the " truffle
liver sausage," so nuich in evidence at the foreign
" dclikatessen " shops, frequently found in some parts of
London. The result was perfectly satisfactory ; a thin
slice of the delicacy yielding ample material for examina-
tion, and for mounting hundreds of slides had such been
desired.

Several different species of the famil\' Tiibcraceae do duty
as " truffles " in the popular sense, nor do the\' differ much
from one another in character. As their name implies, they
bear an outward resemblance to a tuber, such as a small
potato or artichoke. Inside they are composed of liyphae —
the much-branched and anastomosing tubular threads — which
make up the greater part of all fungi. These are packed closely
together, but numerous spaces and channels are found in which
on the ends of the hyphae are developed the asci, or spore sacs.
In most members of this family these are more or less spherical
and contain typically four spores. In my specimen the bundles
of hyphae are of a grayish tint, while the intervals with the
numerous sacs containing brown, almost black, spores show as
a darker mottling on the ground mass as represented in Figure
la, which is a portion only slightly m.agnified (about X 5).
There may be from one to four spores in an ascus and they
are not formed simultaneously (Goebel), so that under the
microscope, while one may be fully developed, others show
earlier stages. The outer coat of the mature spore is thick and
strongly cuticularized and is ornamented throughout the family
with projections of various kinds. In the present species the
large and handsome spores are covered with sharp spikes and
points, Figure lb. A second thinner coat within is easily made
out with careful focussing. The young spores have less colour,
and according to age the characteristic markings of the outer
coat are not so fully developed. As in most of the very large
class of ascomycetous fungi, the asci are elongated tabular
sacs, while the typical number of spores in them is eight,
— though exceptions are not few — the family brought under
notice forms an interesting variety for comparison ; while also
many of its life processes, such as to some extent its method of
growth from the spores and details of the formation of its
fructifications, are still unkriown. J. B.

154

KNOWLEDGE.

April, 1911.

ORNITHOLOGY.

By Hugh Bovd Watt. M.B.O.U.

TH1-: BRITISH ORNITHOLOGISTS' UNION
EXPEDITION TO CENTRAL NEW GUINEA.— The
two members of this party invalided home, — Messrs. W.
Goodfellovv and G. C. Shortridsje — have recently safely
reached London, and the last-named has bronght with him a
large zoological collection, including about eleven hundred
birds. One Paradise-bird is stated to be certainly new to
science, and <^here are fine examples in the collection of the
scarlet and yellow Paradise-bird (Xatitlioiiiclas circlcns),
new to the National collection at South Kensington : the
female of the species was hitherto unUnovvn. King-birds,
rifle-birds, and manucodes are well represented; cat-birds,
grackles and starlings of se\'eral species are numerous, and
parrots of all si^es, from pygmy parrots to great black
cockatoos; also kingfishers, rollers and pittas. The cuckoos
include a rare and curious species {Microdyiiainis parva)
resembling a honey-guide. There are, further, many different
species of pigeons and fruit-pigeons, .and numerous smaller
birds, which are expected to yield the most interesting forms
of all, when they have been studied by the authorities. —
{Country Life, 4th March. 1911. page 291.)

In Ethnology the important discovery has been made by
this expedition of a community of primitive people, wearing
no clothes, having still in use the implements and weapons of
the Stone Age, and unable to count beyond three. These
people occur up the Miniika Ki\ er. in the hitherto unknown
interior of Dutch New (juinea. Lantern slides from these
were shown at the March meeting of the British Ornithologists'
Club.

WA'II'KFOWL IN THE ZOOLOGICAL GARDENS,
London. — .Amongst recent improvements at the "Zoo" is
a new lake for waterfowl, the stock of which is heavier now
than it has been for a long period. It is hoped that one result
may be a very full list of birds breeding this season.

The geese include examples of the Orinoco, upland,
ruddy-headed, emperor, cereopsis. snow (blue and white),
black-headed, bar-headed, Hutchins, and spur- winged. On
the water may be found the conmion, ruddy and Argentine
flamingoes, mandarin, sunnner and Bahama ducks, spoonbills,
.American and Chiloe widgeon, China pintail, cinnamon, blue-
wing, green-wing, Japanese, chestnut-breasted, Andaman.
Brazilian, Chilian, and versicolour teal, rosy-bills, red-crested
pochards, white-eyes and maned geese. In the sea-lion's
pond is a recently arri\ed king penguin, about three feet in
height.— 1 77it' Field, 25th February, 1911, page 384.)

CROSSBILLS IN THE BRITISH ISLES.— An account
of the exceptionally wide-spread visitation occurring in
1909-10, and the phenomenal nesting which followed, is
promised by Mr. H. F. Witherby, of Hritisli Birds, and the
subject was illustrated by exhibits made at a recent meeting of
the British Ornithologists' Club. Nests and eggs were shown,
most of the eggs being those of the Continental crossbill,
obtained last season in different parts of England and Ireland.
Eggs were also exhibited from the Continent, as well as those
of the resident Scottish race of this bird and of the parrot
crossbill, for comparison. The nests showed much divergence
in make and material. The Rev. F. C. R. Jourdain pointed out
that the material for study had hitherto been scanty, and that
there was no authentic record of a case of nesting in the same
locality in England for two consecutive seasons.

THE WOOD-PIGEON PEST.— The number of resident
birds of this species in Wilts, Hants, and other Southern
Counties this winter has been enormousl)- swollen by arrivals
from other quarters. Many of these are smaller in size, and
recognisable as innnigrants from Scandinavia. The birds
were abnormally prevalent and persistent, doing havoc to
clovers and catch-crops, which are specially cultivated in the
counties named for ewes and lambs in the spring months. .A
flock-master at Cholderton. near Andovcr, with four thousand
.acres of ground, estimated th.at .some six tlioiisand to seven
thousand pigeons frecjuented it. In Wiltshire alone the

damage done by the middle of February was said to mount
up to about ;i 30,000. Ordinary methods of scaring and
trapping having proved quite insufficient, a vigorous shooting
campaign was organised. One, two, or three days in each
week have been given to shooting the birds in each neigh-
bourhood simultaneously, as far as possible, following them to
their roosting-places. .A Government Inquiry is being asked
to investigate the extraordinary increase in the species, and
how to deal with this plague to agriculturists.

A GOOD LOCAL LIST.— " The Birds of East Renfrew-
shire," by Mr. John Robertson {Glasgow Naturalist,
February. 1911, pages 41-59; 207. Bath Street, Glasgow. 1,3),
is one of those somewhat notable little works which show how
rich a result follows continuous and careful observation, even
in a not too favourable locality. The district covered is a
limited inland one, encroached upon further and further each
year, by the southern suburbs of Glasgow. Yet Mr. Robertson
records one hundred and fifty - one species, eighty -three of
which ha%e bred. The number of kinds of ducks and waders
which occur, season after season, is remarkable.

THE LATE PROFESSOR ALFRED NEWTON.— Those
who only knew this great English ornithologist by his own
writings and the eulogistic accounts which have been given
of him in scientific and ornithological publications will turn,
with great interest to an article in the March number of
the Coriihill (pages 334-349), by Mr. .Arthur C. Benson, who
was a contemporary of the Professor at Magdalene, Cambridge,
from 1904 to 1907. Mr. Benson's chapter is, of course, not
ornithology, but is an intimate and personal narrative, revealing
a character of a type probably not anticipated by those who
had not personal acquaintance with the man. From this
personal point of view, Mr. Benson's own feelings are thus
expressed; — "I began by fearing him. I went on to admire
him, and I ended by lining him."

■• PHOTOGRAPHY FOR BIRD - LOVERS."— Messrs.
Witherby & Co. have in the press .n illustrated volume
entitled " Photography for Bird - Lovers," by Mr. Bentley
Beetham, a well-known and successful bird photographer.
The book is an essentially practical guide to the pursuit of
bird-photography in all its branches, and Mr. Beetham gives
ungrudgingly- from the store of knowledge gained by his own
personal experience in the field.

PHOTOGRAPHY.

By C. E. Kenneth Mees, D.Sc, F.C.S., F.R.P.S.

THE RELATION BETWEEN THE COLOUR OF
SIL\'ER IMAGES, AND THE SIZE OFTHE PARTICLES
WHICH COMPOSE THEM. — In a former number of
" Knowledge " (December, 1910), I referred to the investiga-
tion of this subject by Schaum and Schloemann, in which
they came to the conclusion that the colours were due to
optical resonance.

At the Royal Photographic Society, on March 7th, Mr.
Chapman Jones ga\e an account of an in\estigation undertaken
by him with a view to the examination of the accuracy of
Zsigmondy's view that it was not possible to deduce the size
of the particles from the colour of a colloidal solution, and
that the colour was dependent to a considerable extent upon
the separation between the particles.

.As the subject of this investigation, bromide of silver,
chloride of silver and phosphate of silver lantern plates were
used, developed by means of developers containing ammonium
carbonate and ammonium bromide, so as to produce carmine
and yellow tones ; while in one series of experiments the
phosphate plates were printed out.

Mr. Chapman Jones adopted a most ingenious method of
measuring the size of the particles. If a silver image be
treated with mercuric chloride and. after washing, developed
with ferrous o.xalate, it adds mercury in the proportion of one
atom of mercury to one atom of silver. A second intensifica-
tion produces an image consisting of one atom of silver and
three atoms of mercury ; a third, one atom of silver and se\en

Al'KIL, 1911.

KNOWLEDGE.

155

atoms of mercury ; so that the particles grow rapidly in size,
and from the known specific gravities of the various amalgams
the increase in the diameter of the particles can be calculated.
Eight such intensifications produce an enlargement of over
seven diameters, and even particles which were at first com-
pletely ultra-microscopic may be thus rendered measureable.

The method appears to be capable of giving results of
considerable accuracy, probably of the order of five per cent,
and the results obtained were satisfactory concordant.
They showed that in films, where the particles were
too small to produce any visible colour, only a faint
blue opalescence being visible, the diameter of the particles
ranged from -10 to -12 microns. If the films were yellow
the diameter was -13 to •14 microns; -15 to -17 gave
orange or brown films, and in one case pink, while -17 to -18
gave purple tones, diameters above -IS corresponding to
brown-blacks and greys.

These diameters are somewhat less than those found by
Schaum and Schloemann for their grains.

The refractive index of gelatine was measured by a number
of methods, the most successful being the finding of a liquid
mixture of known refractive index in which the edge of the
film disappeared ; the result obtained was 1 • 53. Now it will
be seen that the diameters given for the various particles
nearly correspond to the half wave-lengths in gelatine of the
light whose absorption would produce the colour stated, thus
the wave-length of the limit of the visible spectrum. -4 microns
in air, will become -26 microns in gelatine, the half of which,
•13, corresponds well with the diameter of the particles which
commenced to show a yellow colour.

Mr. Chapman Jones gave some remarkable instances of the
accuracy of the relation found between the colour of the
deposit and the size of the particles ; he had examined
images of mixed colours and had always found that such
images contained particles of at least two different diameters,
corresponding with the different colours.

He had also found that where the particles were of the same
size, but were dispersed to different extents, the colours were
the same, thus showing that Zsigmondy's suggestion that the
colour depends on the dispersion of the particles cannot be
substantiated for silver particles in gelatine films.

These results obtained by Mr. Chapman Jones are entirely
different from those of Schaum and Schloemann, who experi-
mented with a chlor'de emulsion developed with various
developers, and also with gelatine films containing silver
nitrate printed out, and who investigated the subject by means
of the ultra-microscope.

The conclusions to which these workers came were : —

(1) In coloured images obtained under their conditions the
ground was coloured and the particles of considerable size,
and black, in opposition to the results of Kirchner and
Zsigmondy, who found that in gold gelatine preparations the
ground was colourless and the particles strongly coloured.

(21 The colour was unaltered by diluting a coloured film
with gelatine and re-coating and drying. The colour was also
little altered "by intensification, bright red becoming dark red,
bright green, dark green, yellow passing through orange to red,
and blue becoming deep violet. The colour was also little
altered by reduction, simply becoming less saturated.

(3) The colour is associated with the thickness of the layer
of grains, as was found by Kirchner for Lippmann films,
rather than with the size of the particles.

It is to be hoped that Mr. Chapman Jones' valuable paper
"ill lead to further work upon the subject, which may result
in a reconciliation of these apparently conflicting results.

THE EFFECT OF COLOUR FILTERS UPON THE
DEFINITION OF A LENS.— If colour filters be used with
a lens, it is clear that considerable attention should be paid to
the optical accuracy of those filters, so that they do not intro-
duce aberrations which may aflect the definition of the image.
Apart from the accuracy of the glass itself, distortion may be
produced in colour filters in the course of their manufacture
in several ways.

In the first place, if the filters are prepared by coating
coloured gelatine upon the glass, then when this gelatine dries

it will contract and bend the glass ; also, when the filter is
cemented with Canada Balsam, too rapid drying or drying at
uneven temperatures will distort the filter ; while, finally, if
pressure is exercised upon a thin filter in its cell, the filter may
easily be permanently strained. If these strains were
symmetrical they would be of small importance, as they would
simply produce a lens of slight positive or negative power, and
so, to a small extent, change the focal length of the lens with
which they are used. But generally they are either in one
direction only, or are much greater in one direction than in
the other, and so produce a cylindrical lens, which introduces
astigmatism. The effect of such aberration naturally becomes
much greater as lenses of longer focal length are used, the
effect varying as the square of the focal length of the lens, so
that a filter which would be perfectly satisfactory on a hand
camera lens of six inches focus, would be with a telephoto
combination quite useless. With medium and high power
telephoto lenses only filters of the highest optical accuracy
can be used.

This point must be carefully borne in mind, in view of the
recent introduction of what may be termed semi-telephoto
lenses, such as the Busch Bis-Telar, which naturally require
that a filter should be far more accurate than would be
assumed to be necessary for its diameter.

The aberrations of filters can be minimised by making them
of as thick glass as possible, having regard to its optical
accur.acy. and for filters of the very highest quality it is usual
for the two glasses to be about five millimetres in thickness.

PHY.SIC.S.

By A. C. G. Egertox, B.Sc.

GENERAL. — Among the events of the last month, mention
should be made that the electromotive force of the Weston
Normal Cell, made up according to specification, has been
accurately found to be 1^0183 international volts at 20"C. ;
standard cells will in future be compared with such Weston
Normal Cells at the National Physical Laboratory. The
Weston cell consists of an H -shaped vessel, the one limb of
which contains mercury and mercurous sulphate, the other
containing cadmium and cadmium sulphate. Its electro-
motive force is very nearly independent of temperatiu'e over
the usual range of working temperatures. The E.M.F. of the
Clark Cell varies with temperature, while its E.M.F. is greater
than the Weston cell, the former having a zinc negative pole
instead of cadmium.

Professor Perrin gave a most lucid exposition of his investi-
gations on Brownian Movement at the Royal Institution on
February 24th. During his lecture he showed, by means of
cinematograph photographs, the movement that colloid
particles undergo when an emulsion of gum and water is pre-
pared and examined under the microscope : their rotation,
their collision, their random path, and their attraction and
repulsion from electrified surfaces were beautifully illustrated.
By an able investigation of the motion of these minute colloid
particles and assuming the motion of molecules to be of the
same character. Professor Perrin has succeeded in calculating
in several ways the number of molecules per cubic centimetre
and mass of the atom of hydrogen, the numbers agreeing well
with those determined by other methods, such as the period of
change of radium, the charge carried by the atom of hydrogen,
the polarization of light and consequent blueness of the sky,
and the values obtained by measuring the viscosity of gases for
the average distance traversed bj- the molecules between
collisions or their " Mean Free Path." The number of
molecules per cubic centimetre is nearly twenty-eight trillions.

THE VISCOSITY OF GASES.— In the Proceedings of
the Royal Society there have appeared lately several interest-
ing communications by Dr. A. O. Rankine. There is much
that is pleasing about a simple apparatus : the viscosity of gases
has hitherto been a somewhat troublesome co-efficient to
determine, but Dr. Rankine is able to find the viscosity of
Xenon, which can only be obtained in small quantity, with com-
parative ease, by means of his apparatus. The apparatus

156

KNOWLEDGE.

Al'Rii.. 1911.

consists of an elongated ring of glass tubing with a branch tube
and tap sealed into the smaller sides of the ring ; one of the
two longer straight tubes is capillary. A mercury pellet in
falling down the tube of larger bore pushes the gas in front of
it through the tube of narrow bore. The time of fall is
proportional to the viscosity of the gas : the more viscous the
less easily can it pass along the capillary bore, and the longer
the time of fall of the mercury pellet. The great advantage of
the apparatus is that only small quantities of the gas under obser-
vation are needed. Dr. Rankine has observed the viscosity at
different temperatures, and in this way has obtained measure-
ments which enable him to calculate the relative attraction
constants, radii and volumes of the molecules of the various
gases. The gases of the argon group — helium, neon, krypton,
xenon show interesting relationships respecting such constants.

THE DENSITY OF R.ADIUM EM.W'.ATION.— Just
as in the series of compounds of carbon and hydrogen -there
is a group of hydro-carbons which are "saturated" and cannot
combine with other atoms without replacement of those
already combined in the molecule, so in the " Periodic
Classification of the Elements " there is a group of elements
whose atoms are unable to combine with other atoms, or
which have zero \alency. These elements are the rare gases
above mentioned.

There is room for one or two elements more in the group
according as to how the natural periodic classification of the
elements is interpreted. The atomic weight of the one would
be about one hundred and seventy-si.x. of the other about
two hundred and twenty-two. Radium emanation or Niton,
as Sir William Ramsay suggests should be its name, is the
first break-down product of the radium atom, and is a gas
behaving in every way as if it should belong to the argon
group, and fit into one of these vacant places. From density
determinations and observations of the boiling-point and
critical point of this highly radio-active gas, it appeared that
its density was such that its atomic weight should be one
hundred and seventy-six. But since only one a particle or
helium atom is expelled during the decay of radium into
radium emanation, it was more probable that the density
should be one hundred and eleven, or atomic weight, two
hundred and twenty-two, unless the disintegration theory
which explains the numerous transformations of radio-active
substances was in fault. It was very important then to settle
the point and determine the density of radium emanation.

The difficulty of such a determination would seem almost
insuperable, for — to put it succinctly — it would require
;f 15,000 worth of radium to get half a cubic millimetre of
the emanation. Sir William Ramsay and Dr. R. W. Gray
have, however, tackled the problem successfully. They
have been able to construct a balance weighing to less than
one-hundred-thousandth of a milligram, so as to be able to
weigh with sufficient accuracy one-tenth of a cubic millimetre
of the emanation.

It required several years of experimenting to design a balance
of such sensitiveness. Dr. Brill, working under Sir William
Ramsay, had improved the Nernst balance. This works by
the torsion of a quartz fibre, one end of the beam acting as a
counterpoise and pointer, but the deflection due to torsion of
the fibre is not directly proportional to the weight. Dr. Brill's
work suggested the employment of quartz knife edges and very
light beams, which idea Dr. Gwyer improved and introduced
a system of weighing which Dr. Steele, in Australia, indepen-
dently arrived at. Sir William Ramsay and Dr. Gray were
able to slightly improve Dr. Steele's balance and modify it for
their purpose. A short description of the balance in a few
lines is unworthy of such a beautiful instrument. It consists
in the main of a fine silica rod beam resting on a specially-
ground and very small quartz knife edge ; from the ends of the
beam is hung, by means of silica fibres, the substance to be
weighed, silica counterpoises and a small siHca bulb containing
air. By altering the pressure inside the balance case, a small
change in buoyancy of the air in the bulb is caused, so by
finding the change in weight produced by a given change in
pressure very fine adjustments of weight can be made ; a
mirror is attached to the beam of the balance, and the altera-

tion in pressure necessary to bring back to zero the spot of
light reliected from the mirror on to the scale, gives a measure
of the alteration in weight.

The emanation was collected and sealed in a very fine tube
which was counterpoised, then broken so as not to lose any
particles of glass, the balance case evacuated so as to expel
the emanation and replace it with air. then counterpoised
again and the change in pressure noted.

Numerous corrections had to be made: the weight of the
air entering the density bulb, after breaking it to let out the
emanation ; the change in the buoyancy due to the fact that
the density bulb is glass and the counterpoise silica ; the
volume of the emanation that penetrates into the glass walls
owing to its high activity, were among these corrections. The
\()lume of the emanation was determined and the amount of
its decrease before the actual determination by its change in
activity.

The density came out to be two hundred and twenty-three
as a mean of five experiments.

The results then confirm the disintegration theory of
radioactive transformations which demands that since the
atomic weight of radium is 226-5 that of the emanation
should be 222-5. Further than this, they demonstrate
the manipulative genius of Sir William Ramsay, and the
success of these delicate experiments in the face of such huge
difficulties reflects great credit on his collaborator.

MESOTHORIU.M.— .\s an illustration of the disintegration
theory, the products of change of thorium might be mentioned.
Thorium first breaks down into mesothorium I., which in eight
years has half broken down into mesothorium II.. which again
is half gone in nine hours, changing into radiothorium and
throwing off /3 and 7 rays; radiothorium then throws off an a
particle (an electrically-charged helium atom) and becomes
thorium X. Thorium X breaks down into thorium emanation,
w hich is a gas ha\-ing a half life period of only seventy-seven
seconds, and breaks down with loss of an a particle into
thorium A which is followed by other products B.C. and D.,
the final product being as yet unknown. Owing to the fact
that considerable quantities of thoria are used in commerce
for the manufacture of incandescent gas mantles, it has lately
been possible to extract appreciable amounts of mesothorium
and radiothorium.

The monazite sand is treated in some way devised by Dr.
Hahu, so as to separate the mesothorium and so on from the
thorium, and such preparations have lately been put on the
market by the firm of Kncifler & Co.. and will doubtless be
used largely for medical purposes.

Professor Soddy has found that mesothorium and radium
are identical in chemical properties — a very remarkable fact.
He points out, too, that thorium, ionium, radiothorium form
one group of radioactive elements, and mesothorium, radium,
thorium X form a second group which are chemically identical
and inseparable elements, although their atomic weights differ
by two units in each case ; while the last member of the first
group and the first member of the last group (radiothorium
and mesothorium) possess the same atomic weight and yet
are chemicalh- different.

THE NATIONAL PHYSICAL LABORATORY.— The
annual meeting of the General Board at the Laboratory,
Bushey House, Teddington, was held on Friday, March 17th,
and in the afternoon a number of guests had the privilege of
going over the Laboratory. They were received in the
building containing the National Experimental Tank by Sir
•■Xrchibald Geikie. who is the Chairman of the General Board.
.Ml the departments w-ere thrown open and members of the
staff were at hand to explain all the w-ork which is carried out.

THE ROYAL AUTOMOBILE CLUB'S SUGGESTED
LABOR.-^TORY. — We learn from the Secretary of the Royal
.Automobile Club that the Expert and Technical Committee
has been asked to consider the expediency of establishing a
central research laboratory for the scientific investigation of
motor car problems and to report .-is to the equipment and
maintenance to such a laboratory.

April. 1911.

kxowl1':dge.

157

ZOOLOGY.

By Proi-hssor J. Arthur Thomson.

THE BIOLOGICAL HOROSCOPE.— Professor D. H.
Tennent, of Bryn Mawr, has been very successful in crossing
sea-urchins of different genera, Toxopiieitstes and Hippoiiuc.
The To.\opneustes influence dominates in sea-water of a
higher OH ion concentration, and the Hipponoe influence
dominates in sea-water of a lower OH concentration. It is
suggested that this variation in the sea-water, brought about
artificially in the laboratory, may correspond to normal
seasonal changes. If so, it throws light on the difference
previously observed between the winter embryos and the
summer embryos of the cross between Spliaerccliiniis and
Stroll jiylocetitrotiis. Thus something depends on the season
of birth, and thus we come back to the horoscope and
astrology — in new guise, of course.

SPARROWS AND POULTRY. — The poultry -raising
industry in many parts of the United States is seriously
menaced by "blackhead" and similar diseases due to parasitic
Protozoa known as Coccidia. Philip H. Hadley has found
that these parasites are abundant in the intestinal tract of the
English Sparrow, which he therefore blames for the diffusion
of the disease. The parasite occurs also in some other wild
birds, such as the American "robin" iMcriila inigratorinK
and severe coccidiosis has been observed in the quail {Col nuts
virginianiis) and the grouse [Boiiaso uinbcllatus). Thus
wild game birds as well as poultry (fowls, turkeys, ducks, geese,
pigeons, pheasants, guinea-hens) are seriously threatened.

LEPTOMONAD IN EUPHORBIA.— Not long ago Lafont
made the remarkable discovery that the late.x of Euphorbia

pilulifcra in Mauritius contained as a parasite a species of
Lcptonionas, that is to say, a kind of parasite characteristic
of animals, and next door to Trypanosomes which cause
sleeping sickness and the like. This very interesting dis-
covery has been confirmed by G. Bouet and E. Rouband in
regard to other species of Euphorbia. They find the infection
local, temporary, and without obvious pathological effects.
They were led to regard a small Hemipterous insect, D/c7(c/j<.'s
hiiiiiilis, as the infecting agent, but fresh experiments by
Lafont, in the case of Euphorbia pilulifcra, point to another
bug, Xysiiis fupliorbiac. as the culprit.

CILIARY AND MUSCULAR MOVEMENTS.— Looking
down from the rocks into the water in the summer seaSon
one often sees a jellyfish and a Ctenophore moving together,
both very beautifully, but in very different ways ; for the
jellyfish is moving mainly by muscular contraction and the
Ctenophore by cilia. It has been shown by A. G. Mayer,
in a series of interesting papers, that these two kinds of
movement have a converse relation to one another. Thus
sodium is the most potent check to ciliary activity and the
most powerful neuro-muscular stimulant. Magnesium is most
potent in maintaining ciliary movement and the most powerful
inhibitor of neuro-nniscular movements. Among reagents of
this sort whatever stimulates cilia depresses muscular activity,
and whatever inhibits muscular movement stimulates cilia.
In nature the more highly specialised cilia, such as those of
the Ctenophore's combs, which are under the control of the
neuro-muscular system, stop whenever the muscles contract
and beat only when the muscles are relaxed. " The dis-
covery of this converse relation makes very apparent the
incompleteness of all existing explanations of the cause of
animal movements."

REVIEWS.

CHEMISTRY.

Xcw Rcdiictiiui Mcfhoits III \'(>lii iiicfnc Analyses. — By I'..
Knecht, Ph.D.. EM. C. and E\a Hibbert. lOS + x. pages.

(Longmans. Price 3 - net. I

This little volume gives, in an accessible form, the numerous
papers published by the authors in different journals upon the
use of titanous chloride in volumetric analyses. Solutions of
this salt can now be readily obtained in a fairly pure condition
and its very powerful reducing properties render it particularly
suitable for use in the volumetric estimation of all kinds of
compound. Full descriptions of the methods of using it are
given here, and in the case of some of these estimations there
had previously been no reliable process of determining the
substance in question. In particular, the application of this
compound to the quantitative estimation of various dyestuffs
will be found especially useful. The book will prove a
valuable addition to the librarv of c%erv laboratory.

BIOLOCiY.

r/(c' Origin of Species by Means of Natural Selection

(Popular impression of the copyright edition). — By Charles

Darwix. 432 pages. 7T-in.X5-in.

(John Murray. Price 1 - net.)

" The Origin of Species " has now passed out of copyright,
but the edition which it is now open to anyone to print is the
unrevised one which was superseded by the present one. Mr.
Murray is to be congratulated on bringing out the popular
impression at a price which is within the reach of everyone.

BOTANY.

Life Histories of Ediiiiliar I'lants. — By Jc.iHN J. Ward,

E.E.S. 204 pages. iS6 plates. S-in. X5-iu.

(Cassell & Company. Price 3/6.)

This popular edition will give Mr. Ward's delightful essays
on the familiar plants a wider circle of readers and will help
on the great movement that is proceeding, whereby the public
generally is being interested in the world of life around it.

Open Air Studies in Botany. — Second edition. By Robert

Lloyu Praeger, B.A. 266 pages. 58 illustrations.

8-in.X 5t-in.

(Charles Griffin & Company. Price 6/- net.)

We are pleased to see that a second edition of Mr. Praeger's
book has been called for as it is not occupied with the
dry-as-dust Botany, but with sketches of British wild flowers
in their homes among the shingle, by the river, in the meadow,
among the corn and along the fragrant hedgerow. Those who
know Mr. R. Welch's photographs will know that the plates
well illustrate the plant associations and habitats with which
they deal.

Aids to Bacteriology. — Second edition. By C. G. IvIoor,

M.A., and WiLLL\M Partridgi;. 240 pages. (6i-in. X4-in.)

(Baillierc. Tindall & Cox. Price 3'6 net.)

This book is a second edition of a little work dealing briefly
with a great number of points coming under the heading of
Bacteriology. In the Introduction general matters ai'e con-
sidered and the various bacteria of disease, methods of
examining them, forms producing fermentation, and the
bacteriology of every-day life are briefly touched upon.

ELECTROGRAPHS.

r.y A. \\". CLAYI)i:X. M.A..

Priiulpal of t/ic h'dYiil Albert Mciimriiil i'iiivcri;ity Colhiic. lixcfcr.

Se\"1-:kai. years a,t;o. when eN|iL'nniciitin,i; with an
early form of Tesla apparatus suppheil to the
College by Mr. Apps, I hit ujion a phenomenon
which deserx'es to be better known. At that time
I belie\'ed the results were novel, but when I came
to describe them I found that similar observations
had been made hv Mr. 1'. ]. Smith at Trinit\-

I'lr.i'Ri; 1.

EK-ctrograph of a kaj,'L' coin (blaned iniagul rrstint,' upon
two small iiifdals.

College, O.xford, and described b\- him (.)n June 24th.
1892, to the Physical Society under the title
" Inductoscript." His method was to place a coin
or medal upon a photographic plate which rested on
a conductor, and then connect the coin and conductor
with the poles of an " Inductorium "' or Transformer
for a time varj-ing from five seconds to fifty seconds.
On development the details of the face of the coin in
contact with the film were revealed. His paper
appears in X'nluiiie XI of the Proceedings of the
Physical Society, but unfortunateh" it is not
illustrated by any reproductions of the photographs.

Seven years later, struck In- the beaut\- of the
discharge from the Tesla transbjrmer, it occurred to
me that if a number of metal bodies were to be
placed upon a sensitive plate it should be possible to
get some sort of reproduction of the surrounding
discharges.

If, for instance, a brass sheet is laid on the
working bench, then a plate of glass, and a coin or
group of coins upon the glass, on connecting one of
the coins with one terminal of the transformer and
the brass plate to the other terminal the coins are
seen to be surrounded by beautiful radiating coronae
caused by the discharge, I therefore substituted
a jihotographic j)late, film side uppermost, tor the
glass and let the discharge [kiss for a second or two.
On developing, I was surprised to see that not only

were tlie details of the radiating discharge far more
perfecth' rendered than I had e.xpected, but the
modelling of the A\hole face of the coin in contact
with the film was sharph' revealed.

In order to get the detail it was necessary to have
the coin actualh' resting on the film. In some cases
it was lifted up a short distance, and the mere
tliicknessof a threepenny bit was found to be enough
to si)oil and blur the image. See Figure 1, in which
the central large coin rests upon the little medals.

Mr. Smith attributed his photographs to the
electric current, or at least the electrification of the
rtlin. but in the case of my observations it is not easy
to sa\' whether the action on the film was due to the
discharge or to the light ol the discharge. A coin
under the conditions of the e.xperiment. that is to
saw in contact with one terminal of a Tesla
transformer, is luminous all over, and the longest
ra\s spring from the sharpest convexities, such as the
the edges of the milled ritu, in accordance with the
general rule as to the distribution of a charge on
conductor,

I am inclined to think that this distribution of
the discharge is the real explanation of the phenom-
enon, though the effect on the silver salt may just as
well be electric as strictK' photographic.

FiGCRK -'.

The effect of the sparUs connecting coins and in the
square hole of the Japanese example.

Howe\er this may be, the experiments are very
easy to make, verv beautiful to see, and yield results
of considerable interest. Note, for instance, the
sharp, slender sjjarks which connect the various
coins, the corona of ratliating siiarks surrounding
i-ach coin, and tlie wa\- in which these coronae
decline to join. This last featiu'e is especially well
shown in the scpiare hole in the Jaj^anese coin shown
ni one picture (F'igure '2), and in the discharge

158

Al'RIL, 1911.

KNOWLEDGE.

159

surrounding the coin common
cross in another (see Figure 3).

to the arms of the

Fig I' UK J.
Coins arran.!;ed in the foi in of a cross.

One specially interesting photograpli (l-"igure 4) is
perhaps that which shows a single coin and seven
small dots. This was taken h\ connecting oni>
terminal witii the coin, then placing some small
shot on the plate (the dots) at different distances,
and hnall}' connecting the other terminal with a ring
of brass wire about six inches in diameter and
concentric with the coin. The discharge was passed
for one second and the plate then developed.

The corona riunul the coin at once calls to mind
the solar corona, and the luminosities attached to
the shot suggest comets' tails. Each shot has two
fans of light, a broad one pointing away from
the centre, which is larger as the shot is nearer.
and a narrower sheaf connecting the shot with
the coin, which dies out with increase of distance
much more rapidly than what ma}- be called the
outer tail.

Without trying to found any argument as to the
nature of comets" tails and the light sometimes seen
pointing from a nucleus towards the sun, the
pictures are certainly very suggestive, and the actual
discharge as seen by the e}-e is much more strongly so.

However, space in these pages is valuable, and
enough has been said. The phenomena are in the
main only what the known facts of the brush
discharge would suggest, except that I feel sure no
one would hiwe supposed that it would be possible
to reproduce such detail without the use of any lens
or camera.

Inductoscripts, electrographs. or mere contact
photographs, whiche\-er they may he, I tliink they
are interesting enougli and curious enough to be
made more common kn(.iwledge.

The apparatus I used w as an induction coil giving a
six-inch spark. \>\' which two medium-sized Leyden
jars were charged. The discharge from these was
then sent through the primary of a small oil-insulated
transformer, and the length of the spark gaj) adjusted
until the wires from the terminals of the transformer
were as luminous as it seemed jjossible to make
ihem.

The coil, jars, and spark gap were covered Iw a
kirge cardboard box so that the photograjihic plate
was not logged b\' stra\' light, but was exposetl ouK^
to the action to be exaniinecL

Fiouui; 4.
Seven shot surrounding a coin.

THE PROBLEM OF THE ROTATION OF VENUS AND

THE INFERENCE TO BE DRAWN FROM THE PROBABLE

ATMOSPHERIC CONDITION OF THE PLANET.

Bv B. G. HARRISON. l-.R.A.S.

In connection with the problems of tidal friction
and planetar\- e\-oliition the question of the rotation
of \'enus is of the utmost importance. Unfortu-
nateh- its period is still a matter of considerable
uncertainty, but is t;enerall\- considered to occup\-
either about twenty-four hours, or else to be efjual
to the planet's orbital revolution of two hundred and
twenty-five days. Although most astronomers favour
the latter alternative, there are serious objections to
either, and it is (]uite possible there may be another
solution to the question. There now seems little
doubt that Mercury alwa\-s turns the same face to the
Sun, but the case is not nearly so certain with regard
to \'enus, either from a dynamical or obserxatorial
point of vie\\'.

Indeed, all the early astronomers assigned U> the
planet a period of about twenty-four hours, but their
data seem to ha\'e been somewhat insufficient, owing
perhaps, to the time of (Ia\- at which their observa-
tions were carried out. The most faxouralile time
is between sunrise and sunset, as tlie planet is then
high in the heavens and its glare is not so pronounced,
on account of the brightness of the sky, while it is
also possible to observe any peculiar features that
are presented for several consecutive hours. Until
recently, however, all observations were carried t)ut
either shortly before sunrise iir just after sunset, and
consequently at much the same time each daw so
that if any markings were noticed on the planet in
the same position on successive da\-s, it ma}- have
been attributed to a revolution having been completed
in the interval.

Until the observations of Schiaparelli. in bsyj, the
idea of a period of two hundred and t\\ent\-Hve da\s
does not seem to have been seriously considered, but
since then many eminent astronomers, including
Professor Lowell, have come to the same conclusion.

If it could be established that Venus were cloud-
covered, it would render this latter altinnative \ery
improbable. For if the planet always turned the
same face to the Sun, unless its thermal conductivitv
is infinitely greater than tliat of the Earth, the
temperature on the dark side \\(_iuld be certainh- low
enough to cause precipitation of the moisture
contained in the hot winds blowing from the
sunward side. There would be a rapid and constant
circulation of air owing to the difference between the
temperatures of the two hemispheres, and evapor-
ation and condensation would be continuous. As
the supply of water could not be replenished from
the dark surface owing to its conversion into ice,
all water \\ould long ago have ceased to exist in

li(]uid form, which would entail a conse(]uent absence
of cloud from the planet's atmosphere.

It is, of course, possible that the surface of \'enus
still has a certain amount of intrinsic warmth, and in
that case the dark side ma\' be in a similar condition to
the De\'onian and Carboniferous jieriods here, as the
clouds \\ould.to a great extent, jnevent the accessor
escape of heat. Now, if we accept this as an
argument in favour of a da\' equal in length to two
hundred and twenty-five of t)urs, we must also bear
in mind the considerable difference in the relative
ages of the planets which the supposition would
necessarily involve. As the densit}' of \'enus is onU-
• N3 and its mass • 75 of that of the Earth, the former
would not onl\- ha\e generated less heat by con-
traction, luit would also radiate it more rapidly and
must, therefore, liaxe been evolved much more
recently to be still in a more primitive condition
than the Earth. The mimnunn period of terrestrial
rotation is unknown, but was possib]\' fix'e hours.
It. however, we assume that tlie Earth and X'enus
each had an original rotational \elocit\' proportional
to their masses, and that that of the former has
been diminished to its present speed by lunar and
solar friction, it is obx'ious that the more recent the
formation of X'euus is considered to be, the less
likely is it that it should have alread}' reached its
maximum rotational period owing to secular tidal
action.

There is no doubt that a dense envelope of some
sort surrounds the planet. The appearance of a
luminous ring and the " black drop '" observed at
recent transits, are alone conclusi\e proof of this,
while the irregular and graduated appearance of the
terminator also furnishes us with further evidence of
its presence. Then, again, the extraordinaril)- high
albedo of \'enus almost prohibits the assumption
that it is the actual surface we see. Moreover, the
dark markings which ha\e been frequently observed
scarceh' exhibit the permanency one would expect in
the case of furrows on the face of the planet, and it
is quite possible they may be caused h\' con\ection
currents effecting openings in the clouds. In any
case, it is diificuh to understand how it w<iuld be
possible to see an\- detail on the surface itself when
one considers this is probably surrounded by a
mirror which reflects 92 per cent, of the light
re;cei\'ed. It is this \'er\ high reflecti\'e index which
presents some difficult\' to the theor\- of a i loudy
atmosphere. Until recently cloud was considered to
be the highest reflecti\'e surface of a planet. Now
as its albedo is only 72 it seems scarceh' enough to

100

April 1911.

K\o^^•L^D^,E.

161

account for the brilliancv of \'e!iiis and this point
has been brought forward as an objection to the
cloud theory. Since it was necessan,- to give some
ahernative explanation, it has been suggested that
the light is reflected from minute particles of dust
suspended in the atmosphere, but this idea does not
appear altogether satisfactory and it is possible to
find another reason for the unusual brilliancy of the
planet. The mean temperature of the air on \'enus
must be considerably higher than that of the
terrestrial atmosphere, and should be taken into
consideration. This would necessarily involve the
attainment of a higher altitude and diminished
pressure for the formation of clouds, which would,
therefore, be probably thinner than ours, and would
be covered by a film of cirrus extending almost
to the limits of the atmosphere. It is well
known that an attenuated substance is capable of
reflecting more light than when condensed, and the
rarefied condition of the clouds might thus account
for the abnormal albedo of the planet. The peculiar
appearance of the terminator, caused by the
prolongation and occasional detachment of the cusps,
can also be most easily explained hv the theorv of
cloud reflection.

.\nother peculiarit\' has been noticed more than
once when \'enus has been examined under suitable
conditions. The dark portion of the sphere has
been found to emit a faint luminosit\' similar to that
observed on the new moon. We know this latter
spectacle to be caused by the reflection of light from
the earth on the dark portion of the lunar surface.
In the case of \'enus. there is no one bodv capable
of transmitting the necessar}- illumination, and its
cause has always been rather a mvstery to astro-
nomers. Now this phenomenon, which for want of
a better name may be termed '' starshine," has been
advanced as an argument in favour of a rotation of two
hundred and twenty-five davs. It has been pointed
out earlier in this article that under these conditions
if there were water on the planet it must all have
been deposited on the dark side in the form of ice :
and it is suggested b\" supporters of this rotational
theory that the ghostlv appearance sometimes
observed is caused by the light from the Earth
and stars mirrored on the ice. .\ moment's con-
sideration will, however, show the impossibilitv of this
idea. It is generally admitted that the whole sphere
is surrounded by a dense atmosphere, and this would
be quite sufficient to prevent the greater portion of
starlight from reaching the surface, even in the
absence of clouds. A\'hen one considers that the
sunward side, where no ice can exist, is capable of
transmitting over 90 per cent, of the light received,
it is hardly necessarv to invent an ice mirror to
account for the " starshine "" on the dark portion
of the planet.

The evidence of the spectroscope shows that water
vapour is probably present on \'enus and thus this
instrument adds its testimon\- to the likelihood of a
cloud-laden atmosphere. At the same time the spec-
troscope gives no evidence of rapid axial rotation.

It is well known that a rotating body, which emits or
reflects light, displaces the lines of the spectrum.
This gives the latter a twisted appearance, owing to
one limb of the sphere approachiiig the observer,
whilst the other recedes, and thus altering the relative
wave-lengths of the light. The amount of this alter-
ation for a given speed of rotation is well known, and
as it is i)ossible to obtain by these means the angular
velocities of the Sun, or any body whose diameter is
known, and compare them with the results obtained
by visual observation, the accuracy of this method
has been indisputablv proved. Naturally, the lower
the velocity happens to be, the greater is the difficulty
experienced in its measurement by these means, but
in the case of a body having a diameter of seven
thousand seven hundred miles, any motion involving
a rotational period of less than two months might be
detected.

As the spectroscope has failed to show any shift
in the spectral lines, this presents an almost insuper-
able obstacle to a period anything like so short as
twentv-four hours. We have also seen that a
rotation, which would cause the planet to turn the
same face always to the Sun, is incompatible with the
presence of water. We are thus led to conclude
that the planet's da\' is between two months and
two hundred and twenty-five of our days in
length.

This is rendered more probable since the slow
axial rotation which this hypothesis necessarily
involves would be almost impossible to detect from
observation. Schiaparelli himself admitted that the
planet's da\" m.ight be any period between six and
nine months in length, and it was, therefore, con-
cluded somewhat prematureh- that if \'enus had
no visible rotation it had already reached the stage
when the same face was always turned to the Sun.
If this has happened there must have been an inter-
mediate stage when the planet's day was shorter
than its \ear, but still not short enough to enable us
to detect anv motion, niid there is no evidence to
shoic that this sta}>e has yet been passed. \\'ith
the exception of Mercurv all the other principal
planets appear to have rotations of twenty-four
hours or under, and if their periods are eventualh-
lengthened until they are synchronous with their
respective orbital revolutions, the time required for
this process will be extended as their velocities
decrease, owing to the consequent reduction of tidal
friction. This friction w ill also be further diminished
since time will cause an increasing rigidity of each
planet on account of its gradual loss of heat, and in
the case of the inner planets through the escape of
water vapour by molecular activity. Consequently,
the final stage of rotational independence will be
prolonged for a considerable period before it is
completely controlled by the sun, and this renders it
likelv that \'enus still has a somewhat shorter day
than its \"ear. Moreover, the only friction capable
of acting on \'enus is that generated by the solar
tides, and although, as their capacity for retardation
varies inversely as the sixth power of the distance.

162

KNOWLEDGE.

Aprii.. 1911.

these are seven-and-a-half times more effective than
those on the Earth, the rotation of the former planet
has never been checked b\- lunar action, which in
our own case may have been an exceedini;l\-
powerful factor in the earlier stages of evolution. It
therefore does not seem improbable even from a
phvsical standpoint that the length of the Cytherean
dav is shorter than it? year, and this supjiosition
would meet most of the difficulties we should other-

wise ha\-e to contend with. There is also, of course,
the possiliilitx- of the planet hax'ing a slow retro-
grade motion, although this is \'ery unlikely on
purel\- d\-namical grt)unds.

.\ltogether the importance of this rotational ques-
tion can scarcely be over-estimated, and the necessity
of obtaining further information on a subject about
which so much uncertainty exists, opens u\) an
admirable field of research for amateurs.

REVIEWS.

PHVSICO-CHEMISTKV.

Thcoric Physico-Cltiniiqiic dc la ]'ic cf Generations
Spoiitiini-cs. — By Stephank Lhdlc iProfesseur a I'ecole de
^Icdecine de XantesI, Paris. 204 pages. 57 illustrations.

(A. Poiiiat. Price 5 francs.)
This little book gives an excellent summary of some of the
most important physico-chemical processes that take place in

the presence of certain poisons, but whereas colloidal platinum
may be rendered active over and over again, an enzyme such
as diastase is destroyed by a moderate degree of heat, and its
activity can never be restored. In fact, it might almost be
possible to form an enzymic definition of life. \\'hen once an
enzyme has been produced without the aid of a living
organism the possibility of proving spontaneous generation
will be nearer than it is at present.

AfrJi::,s >J tic Ri^u'itl^iii Kay.

l-ic.LKi, 1. Dsuiotic drowtli^

living organisms, and in particular of osmosis. The author
shows by a series of extremely interesting photographs
(of which one is reproduced in Figure II, that it is
possible by introducing mixtures of certain salts into
solutions of other salts to produce, by osmotic pressure, forms
analogous to those of plants and the shells of aijuatic animals.
These forms may be used as illustrations of the mechanism
by which the forms of living organisms were possibly produced,
but, in our judgement, it is straining analogy of form too far to
regard them as evidence of spontaneous generation. The author
does not succeed in bridging the gulf between the force that
causes a crystal to form in a certain way and the force that
we know as "life." He refers also to the analogy between
Bredig's so-called "inorganic ferments" and enzymes such as
pepsin and diastase. In both cases the action is inhibited by

PHYSICS.

Radinin : Its Pliysics and Therapeutics. — By Dawson

Turner, M.D., F.R.C.P. S6 + x. pages.

(Bailliere, Loudon, 1911. Price 5 - net.)

In this book. Dr. Turner has summarised in a concise yet

readable form the various researches published in scattered

scientific journals upon the physical phenomena of radium.

He has also given a description of the uses to which radium

has been put as a curative agent, illustrated by outlines of the

cases and photographs, which are obviously more intended for

the medical than for the general reader. It is in fact with the

therapeutic part of the subject that the book mainly deals, and

it appears to us to be admirably suited as a guide to medical

men who desire a handy manual upon radium.

Knowledofe.

With which is incorporated Hardwicke's Science Gossip, and the Illustrated Scientific News.

A Monthly Record of Science.

Conducted by WiUrvd Mark Webb, F.L.S., and E. S. Grew, M.A.

M A Y, 19 11

PLANT HAIRS.

Bv K. E. ST VAX.

IXTKOIU'CTIOX.

ji'ST as there is a reason for "all thiii^i
the sun." so there is a reason \\h\ plant
pdssess hairs on some of
their man}' origans. Thev
are placed where we find
them for a definite purpose,
and tiny as the\- are. these
delicate hairs — these pur-
poses are wonderfully
carried out ! Do not the
hairs on nettles. which
are long, sharp - pointed,
and full of a burning,
acrid secretion that "stings"'
when pierced into one's
fiesh, help to keep at ba\'
browsing animals, insects,
and an\-one who tries to
do damage to the plants ?
Does not the dense, webby
growth of hairs found on
the mulleins and numer-
"us other plants cause an
unpleasant sense of choking
to anything that tries to
eat them, and so acts as a
deterrent as would a piece
of flannel ? Again, the pre-
sence of hairs is a guard
against the attacks of aphis
and other blights of a
similar natiue. and is also a protection agai
excess oi drought, or the too hercel\- burni
of the sun. Plants found in very hot

situations are often clad in a thick felt-like dress,

under so that the>- may check too rapid e\-aporation of

should the moisture drunk in by their roots, and so liye

and thri^•e in safety.
Agauist an\' excess of damp
and cold a hairy dress is
equally protective, and thus
we find hairy plants are
common in very cold locali-
ties as well as in very hot
ones, at yery liigh as well
as in low altitudes. So,
too, do hairs help a plant
to climb and cling ; to suck
up food (as root-hairs), to
disseminate its fruits and
seeds, to protect its delicate
and essential organs (yiz.. sta-
mens and pistils), to guard
the pores in leaves, and in
many other ways to act as
most necessary organs essen-
tial to the life of the plant.
In forming the delicate silky
fringes on leaves and stems;
the beautiful silvery or col-
oured hairy appendages on
flowers : and the " felt,"'
"web" and woolly coverings
of man\- a plant's surface,
Nature made structures of
infinite loveliness and
outline. We may see them,
ng rays en iiius.'ie. an\- da}-, and admire the softness
burning and richness of their make, but it needs the

Figure 1.

Forked Hairs from the Cor
\'egetable Marrow

la of the

list an\'

^tranifcness

if

163

164

KNOWLEDGE.

May. 1911.

mti Trst

\\ I Htlu'
UIKIII

It.

microscope to show us the true knehness of each

individual kind of hair. For there are very

many different kinds, and each, in its \va\-,

holds some, cliarm : some. too.

show choice colours, others

emit pleasant or disagreeable

odours ; some produce oily or

viscid exudations, whilst others

form secretions with peculiar

properties, such as hitter. (Priiu-

ula sinensis). lemon\'. saltish,

sugar\- and burning (stinging

nettle). Some we find are very

smooth-coated, others \er\- rough,

whilst — internally — one hair may

be built up of a number of separate

cells, and another may consist

of merelv one, long and narrow

or broad and rounded as the

case may be.

If we look at an\' two hairs.
either is different from the other :
no twt) are ever quite alike, and
herein lies the absence of all
monotony. Each is an object of
itself : something trul\- marvellous,
the closest scnitin\' w u (-an bestow

Amongst the man\- different
kinds met with, the following
are the principal :— 1 1) Forked,
(_') Hooked, (3) Glandular, (4)
Branched. (5) Stinging, (6) Stel-
late, (71 Peltate, (8) Jointed,
though, perhaps, those known
as Root-hairs should be con-
sidered chief of all, since the\-
are, truly, the means hv which
a plant derives its food from
the soil in which it grows, and
is able to perform its life's func-
tions. They are the most useful,
though their li\'es arc \-erv brief,
and, at the same time, some of
the most simple in form that
can be met with an\where.

I. — Forked and Hooked
Hairs.

Forked, or. as the\" are also
called, barbed hairs are often
extremely curious as well as
beautiful in form and are \er\"
frequently met with on plant
surfaces. Their distinctive feature
is, that the hair pedicel, or stem,

terminates in two or more prongs which are some-
times thick and rounded at the tips, but mcjst
often ver}- sharp-pointed : sometimes, too. the\-
are quite erect in position, whilst at others they
become curved.

Some quaint examples nia\' be seen in the
accompanying illustrations. Figure 1 shows forked

FiGl'KE 2.

Forked Hairs from ihu Skin
ol the Gardi-ii .Auhrclur.

d those that.

Fork.

hairs found on the blossom of vegetable-marrow.
It ma\- be noticed that the hair consists of a
number of thick cells placed one on top of the
other till quite a long pedicel is
formed, and then that the pedicel
di\-ides off into twd thick
branches, or prongs. In the
smaller hair illustrated, it will
be seen that the [)rongs are
being formed.

Figure 3 represents barlied
hairs that abound on the leaves
of our Wild Rough Hawk-bit.
Each prong will be seen to be
very sharp-pointed. Figure 2
is a specially prett\- example of
a three-pronged hair from the
stem of Aubretia. a plant so
fa\oured in our rock-gardens
and rock edges of borders.
The \\a\- ill which the sharp
prongs spread out from the tip
of a somewhat short, thick stem,
is ver\- suggestive of a fork.
Hooked liairs are also known as curved or
iw-likc. and are found largel\- on climbing plants
whilst not being in the true
sense climbers. straggle up
hedgewa\s, and in and out
of the Luidergrowth of copses.
The\- are \er\ useful to such
plants, for the\' act as small
.L^r.ippling irons and readih' catch
oil to an\' foreign suppoits.

Figure 4 shows cur\-ed hairs
found on the leaf of the garden
scarlet-runner bean. They are
lieautiful little structures and
most usctul as climbing supports,
tiny though they are. Figure 6
represents the saw - like hairs
h)und on e\er\- surface, stem, leaf
and Hower of wild Cleavers; a
plant that grows in rank luxuri-
ance in most of our hedges
and copses ; a " weed "' that
often causes great annoj'ance by
the persistent wa\' in which it
clings to one's own clothing
when wandering along the
countrxside. Strange, indeed, are
the hooked hairs met with on
^\ild Hop (see Figure 5). another
climbing plant of English hedge-
rows. On stem and leaf these
curious hairs abound, and one needs only to see
their formidable appearance to understand why
it is that in wet weather (when the hairs are
specialh- stiff), if hop - picking, or wandering
carelessly between the hanging sprats in a hop-
garden, one's skin becomes so terribl}' torn: the
hooked hairs are rea]l\- able to tear and cause great

Figure 3.

d Hairs from the Leaf of
KouKh Hawk-bit.

mav. I'm.

KNOWLEDGE.

165

soreness to liands and face. Each hair is bulbous, awn. This aw n show s two distinct forms of hairs : —

or swollen at the base, and gives off one or two (1) beautiful slender, long silky ones, that easily catch

apex : when two are present the wind, that wafts the fruit about. (2) glandular

the w hole structure ones that are extremeh- sticky : these help the wee

has the appearance fruit to adhere to anything with ^\hich it mav

curved arms at its

Figure 4.

Hookud Hairs from the Stem of
the Scarlet Runner Bean.

of a bull's head.
.Many hooked hairs
are \'er\- rough to
the touch, t h e i r
upper cells show-
ing excrescences
of various kinds :
these are also
useful adjuncts to
the plant for
climbing purposes.

II. — Glaxdii.ar
Plant Haiks.

,\mongst

FiGURi; 5.

Hooked Hairs from tlit
Wild Hop,

this
class of hairs —
one of the most numerous of all — are found
structures of the most varying t\-pes.

.\ typical glandular hair consists of a more or less
swollen base, a pedicel that is
either long or short, and, at
the tip of this, a head — or cap —
that assumes in different plant
species a great variety of
shapes. In some plants it is
o\'al (White Campion), in others
triangular iS[)eed\\ ell), and very
frequently indeed it is circular.
In this cap. or head, are secreted
oils, irritant juices (Primula
ohaiiiicd). resins, gums, and
peptonising digestive fluids, as
the case mav be. to whose

presence are due the var\-ing colours, odours and
flavours met with amongst plant -hairs. These
properties are useful in attracting or warding off
welcome or unwelcome insect \-isitors. in catching
and digesting insects (as do the tentacular hairs on
Wild Sundew and other insectivorous plants that
live on the food trapped and digested b_\- their
hairs), also in protecting \-oung buds whilst
developing.

The hairs that play such an important part in
doing this latter work are peculiar glandular ones
called coUeters that are present on leaf-buds, and,
after rapidly maturing, usualh' die away as soon
as the bud reallv begins to open. The\' secrete
a watery gum mucilage, together with drops of resin
or balsam, which become laid over the surface of the
bud, thus forming a protection for the delicate struc-
ture the}- guard. In Ribes. Salvia and Honeysuckle,
gum is largeh' present in the colleters. Many
plants show more than one kind of liair on the same
structure, each kind ha\ing its own si)ecial function
to perform. Thus the Marsh Avens produces a
tin\- fruit (achene) that is provided with a feathery

come mto contact.

Beautiful beyond all description are the glandular
hairs on the Sundew, nor can anyone who has ever
seen a mass of these plants, growing on a large area
of bog-land, ever forget the sight of the reddish-
hued hairs glistening and sparkling in the sunlight like
vast m\riads of diamonds. Each hair tip (when in
a state of quiescence) shows a bead of silvery,
shining secretion, and the effect of this, as a
sunbeam streams across it. is one of infinite charm.
In the accompanying illustrations are some glandular
hairs often met with. Figure 10 shows triangular-
headed hairs from the leaf of A triplex patiila — a com-
mon "weed." Figure 11 is a very much magnified
hair from the cahx of Purple Dead Nettle, show -
ing the inan\' cells and circular tip with which
the hair is built up. P'igure 9 are quaint hairs
from the sepals of Sweet Pea. These hairs are
extremeh- bulbous at the base, but very long and
slender above, and they bear no "cap" at the tip
of the pedicel. In the swollen
base, full of glands, the secre-

Figure 8,

St

well worth

Stem of tliL

tions are formed,
showing hairs from the stem of
London Pride, is
studxing, for the microscope
can hardly show- any hair groups
n-iore loveh' than those found
on this plant. One mav liken
them to rows of long, slender,
silver\--hued, stemmed goblets,
springing from a slightly spread-
ing stand, and ending iti a
circular bow-1 filled with a rich
rubv-coloured wine. The whole plant is covered with
these exquisite little forms. In Figure 7 are seen the
curious hairs from the leaf of \\'hite Bryony: note
the curious glandular tips composed of man}- cells.
Figure 12, too, is very remarkable. The leaves of
Arctofis are covered \\ith a thick "felt." and under
a microscope we find that this is made up of a mass
of slender intertwining thread-like hairs, whose bases

Figure 6.
Hooked Hairs from the Stem of Cleavers.

One kind of hair is

circular and glandular

and the other, long and brick-like.

The tips

differ.

below-

of each give off a

and out, interweaves, and forms the "felt" we see

and admire so much even with the naked eye.

ver\- long thread that turns in

Glandular Haiks.

FlGl'KH 7.
'roiu the Leaf ot White Bryony.

Figure 8.
From the Stem of London Pride.

FlGiKE n.

From the calyx of tlic
Purple Dead Nettle.

FlGUUK 12.
I'nini tlu' " fi'lt " of the Leaf of Arcfotis hrcvistuiiixi.

(To be continiicd.)

EUTECTICS.

i;y J. L. W. RHODES, Assoc. Ixst. M.E.

It has long been known that most alloys melt cufccfic jioint and the allo\- the eutectic allo\-.

at lower temperatures than their constituent The question now arises as to why this alio}-

metals. should possess such peculiar properties. Is it a

Thus solder containing 32 per cent, of lead chemical compound, since it possesses definite com-

and 68 per cent, of tin melts at a lower position and melting-point ? To this we can say no

temperature than either tin or lead ; and fusible at once, for every chemical and electrical test shews

allo}-s consisting of lead. tin. bismuth, and that the eutectic contains free lead, free tin, and

sometimes cadmium, melt readih' in hot water. nothing else. To soh'e the difficult\- the microscope

FiGUKE 1.
Micropegmatite in dioritic granophyre.

Figure 2.
Perthite parallel to basal plane.

Figure 3.
Perthite parallel to clinopinacoid.

The same princijile has been found to apply
to salts: thus fusion mixture consisting of sodium
and potassium carbonates in molecular proportions
melts much more readilv than either of them. The
use of fluxes in metallurg\- frequently furnishes
another instance, so that we ma\' regard the fusion
of alumina in presence of crxiilite as due to a similar
lowering of melting-point.

Let us now take up the study of the tin-lead
alloys and plot out the melting points against the
percentage of tin. We find our curve consists of
two branches with a cusp shown at A in Figure 4.
The increase in the percentage of tin continuously
lowers the melting-point until A is reached at 180" C
and 68 per cent, of tin after which the melting-point
rises continuously. This point is called the

is brought into use. It is at once seen that of all
the allo\-s the eutectic is the onl}- one that is
homogeneous: all the others consist of more or less
perfect crystals imbedded in a fine grained matrix
identical with the eutectic.

It is now easier to understand the phenomenon.

Taking an a\\o\ fairly rich in lead, X in Figure 4,
we see that as the temperature falls no crystallisa-
tion occurs till we reach a point Y on the curve
when pure lead separates out and the temperature
falls along the line YA. When .\ is reached all the
lead o\-er and above eutectic proportions has
crystallised out and the tin and lead remaining
crystallise simultaneoush'. .A eutectic point is there-
fore the point at which two substances crystallise
simultaneoush'. Now if this occurs, obviously each

167

168

KNOWLEDGE.

May, 1911.

substance xsill interfere with each other's crystalH-
sation, so that we shall get a mass in which the
component crystals are very intimately intergrow n.

Let us now turn from allo\s to the applications
of this theor5' to the crvstallisation of rocks.

Few rocks have been svnthesised, but nian\- rock-
forming minerals have been crystallised from slags,
and Vogt has successfulh" tackled the determination
of some of their eutectics. Thus he has found that
68 parts of augite to 32 of oli\inc
form a eutectic, and so do 70
parts of plagioclase felspar toiO ot
olivine. .\nd this has been
proved to hold in the igneous '-;
rocks, for Harker has she\\n that t
in allivalite (a rock composed of
olivine and the lime-bearing
plagioclase vanorthite) the anor-
thite al\\a\"scrystallised first when
constituting more than 70 per
cent, of the rock, otherwise the
olivine crystallised first.

In LS88, Teall suggested that
the curious intergrowth of quartz
and felspar known as micropeg-
matite was a eutectic, and \'ogt
shewed from a chemical analysis
that the ratios of quartz to
felspar in micropegmatite was
26 to 74.

Hitherto we have been restrict-
ing ourselves to substances which
do not shew any crsstallographic
relationship. W'e must now
examine the melting-point curves
of isomorphous mixtures an<
touch upon the in\'estigations o
Bakhuis Koozeboom. He found
that the curves fell into five
groups, of which oid\' two neec
at present be examined. Taking
the enstatite-hypersthene series
of isomorphous metasilicates,
where crx'stals of ever\' possible
composition can be obtained,
he found that instead of one
he obtained two curves, the
freezing-point cur\e or liqiiidtis,
and the melting-point cur\e
or solidiis. Thus a liquid of
the conqiosition A gi\'es rise
to crystals of the composition
B, since crystals of the com-
position A would have melted
ature. This curve (shewn in Fig
his Type L Instances, however.

FiCl'KI, 0. 1-

XOlJZOtH

at

this temper-
re 5) constitutes
are frequent of
imperfect isomorphism in w hich one constituent. X.
will only hold a certain amount of the other, Y, just
as ether and water will only mix in certain
proportions. This imperfect isomorphism gives
rise to Type IV, shewn in Figure 6, where the upper
curve, the liqiiidus, is seen to have a eutectic point

formed not of the substances Init of the mixed
crxstals A and 15. each of which contains both
constituents. This has a very interesting application
in the case of perthite, a peculiar intergrowth of
orthoclase and plagioclase. Orthoclase may contain
uj) to a certain percentage of albite, being then
known as soda orthoclase, whilst albite may likewise
contain a limited amount of orthoclase. This is
because ortlioclase being monoclinic and plagioclase
triclinic, perfect isomorphism is
impossible; nc\-ertheless the re-
3»6'- lationship is both chemicall_\" and
crvstallographically so close that
small amounts of one can form
mixed crvstals with the other.

The importance of eutectics
in rock formation is ver}- great
and the conditions are often
very complicated, there being
frequently several successive
eutectics between different pairs
of minerals. A condensed
account of the crystallisation of
a granophyre ma\- give some idea
of the role of the eutectic. The
rock to be described consists of
f e r ro m ag n esi a n m e t as i 1 i c a t e s
which crvstallise out as augite,
alumino-alkali anhydrosilicates
wliich form felspar, and quartz.
The augite first separates out in
well-formed crystals ; then the
felspar builds large more or less
perfect crxstals termed pheno-
crx'sts, until the eutectic compos-
ition is reached, when the
fels()ar and quartz remaining
solidif\- as luicropegmatite, \\hose
felspar is in optical continuity
w ith the phenocrysts.

Besides these micropegmatitic
or granophyric rocks, there are
manv whose ground-mass is too
fine to be resolved b\' the micro-
scope, but has been shewn chemi-
cally to be nearly eutectic in
composition. S[)herulites of
niiiuite radiating fibres are found
ni them, and these have been
shewn in some cases to consist
of micropegmatite. Hence this
grouiid-niass has been supposed
to represent the eutectic on a
scale, and is termed amphi-eutectic.

Type I\',

cr\'[itocrystalline

that is, almost eutectic.

It only remains to add that a classification of
rocks has been seriously proposed on the nature of
their eutectics. Its advocates regard the eutectic as
the dominant feature of the rock. It is being
\-igorously opposed by the school of petrologists who
place chemical composition first; but time alone can
decide between them.

*«.- ..« ^-

IJA ^•M^'^^W

I-v i:n(i permission of

— ^h.^ys. -^\T '-^.% ■"n-^^.^.-isa.^

tiic Dirc':tor of the National Physical Laboratory.

FiGt'RE 1, Tho Mxperiiuental IJ.isin and Carriage for towing Models,

THE NATIONAL EXPERLMENTAL TANK.

WORK AT THE NATIONAL PHYSICAL LABORATORY.

Bv E. S. GREW

At last the National Experimental Tank, which models represent. The National Experimental Tank
public subscription and private benefaction have set is intended for much more recondite experiments

up within the precincts of the National Phwsical
Laboratorv, Bushy
Park, is completed : its
equipment is undergoing
test : and \\ ithin a \-er\"
short time the ship-
building i n d u s t r \- of
Great Britain will be
served bv an instrument
of precision unsurpassed
in anv other country.
Speaking roughly, one
may say that an experi-
mental tank is designed to
test the resistance which
is offered bv the hulls of
ships to passage through
the water. The desired
knowledge is obtained
bv tow ing wax models of
hulls of given shape and
dimensions through
the water of the tank,

and (after their resistance to towing has been ascer
tained bv the most refined methods of measurement

than are indicated in

the foregomg sentence ;
but the uses of such
experiments — which
are constantly- being
made in the experimental
tanks of the German
shipbuilders, as well as
in the tank belonging
to Messrs. Dennv, of
Dumbarton, and in the
naval yards of the great

Powers — ma\- be readil\-
made clear.

Let us consider, for
example, some of the
problems which confront
the designer of a tor-
pedo-boat destroyer.
He has first of all to
derive a high speed from
his craft. But he can-
not put in as much
engine power as he
pleases, because that plan may result in an undue
weakening of the hull, or in sinking the hull too
by converting the results thus arrived at into terms low in the water, or in depriving the vessel of the

Hy khtd pt-rttthsijn o/ the Diuxtof o/ the A^ationa! Phys'ual Laboat.^'y,

Figure 2.

Small Tank to be used for experiments with the water flowing
past the Model, the latter being held in a tixed position.

of the larger hulls of iron, wood or steel which the necessar\- room for armament

accommodati

169

170

KNOWLF.DGE.

May. Mil.

Therefore his designs are hmited in various
directions, and it is onh- b\- sliglit alterations in
the shape or in the flotation Hnes of the hull
that he can expect to lessen its resistance to the
water through which it is to he dri\en. The effect
of these alterations can be tried, of course, hv
building a large number of \essels : but evidenth-
the cheaper way, if it is equalh- trustworth)', will

shape and resistance, a considerable effect on the
vessel's speed. One ma\- think of the resistance
offered hv a ship's hull against its forward move-
ment through tlu' water as being composed of
a frictional resistance and a wave- and eddv-
making rc-sistance. The first kind of resistance
is brought about hv the friction of the immersed
surface of the ship's hull w ith the water ; the

/Vy i^i/iif pei-iitissiott of

/'/:ysic'al Lahoratoiy.

Figure 3. Model-niaUing Appar.atus.

l)e to experiment with \arious types of models,
which being made (for example) of wax. can actuall}'
be altered to different shapes.

The larger the vessel of which the most desirable
shape has to be ascertained, the more numerous the
difficulties. All sorts of new factors of resistance to
passage through the water are introduced. The hull
of an ocean liner, or an ocean tramp, or a cruiser,
is not smooth. It is studded with bilge-keels, pitted
with shaft-escapes, and has other openings and
projections in its sunken sides. The rudder, as it
moves, causes resistance: and the rudder has to be
protected. The propellers also exercise, by their

second b\- the formation of waves at the bows
and of waves and eddies around the stern.

These coefficients can be found empirically by the
aid of the wax models. The frictional resistance
depends on the size and nature of the immersed
surface, on tin- dcnsit\- ot the water, and on
the speed at which the ship or its model is
dri\en or towed. As the frictional coefficients
for the different kinds of surfaces of ship and
model are known — they varj- not only with
the nature but the lengths of the immersed
surfaces — the fric-tional resistance may be ascer-
tained matluinatuiilK' without difficultv. If the

NFav, IQll.

KNOWLEDGE.

171

/■r kiiui />i-ymiss/on o/

Figure 4. General View of the Experimental TanK

■ The Daiiy Grafikh.

By kind pernnssioii of

Figure 5. A Wax Model of a Hn

172

KNOWLEDGE.

May. 1911

total resistance of the model has been found by
towing experiments the \\a\e- and eddy-making
resistance, -which is not mathematicalh' ascertainable,
can be found bv subtracting the frictioiial resist-
ance from the* total resistance.

Newton's law of mechanical similarities, first
applied b\- Froude in the calculation of the resist-
ance of ships, and therefore called " Froude's Law,"
enunciates the theorem that if two geometricalh-
similar ship bodies are mosing at corresponding
speeds through the water, the wave- and eddy-
making resistances of these bodies are proportional
to the third powers of their linear measurements
or disjilacements.

.Vs soon as the wave- and eddy-making resistance
of the model has been found by experiments it
need only be multiplied by a'^ — the third power of
the proportional displacement of ship and model —
in order to obtain the corresponding resistance of
the ship. If the frictional resistance of the ship is
added to this resistance the total resistance of the
the ship can be found hv a simple mathematical
formula.

It will bo readilv understood that in experiments
of the nature indicated the most important instru-
ment (if precision is the towing carriage, the
mechanism which registers the resistance to towing
set up by the wax models. The carriage at
Teddington spans the \\ hole w idth of the tank and is
borne on four wheels. thirt\-six inches in diameter,
which travel on rails built on the sides of the tank.
It is made entirely of steel and the illustration
(see Figure 1) gives a better idea of it than an\-
description. Its dimensions are thirty-two feet six
inches by thirt\-four feet six inches and its weight
including all motors and electrical equipment,
but excluding the model dynamometer and other
apparatus, amounts to fourteen-and-a-half tons. The
carriage is driven hv four motors and can be run at
more than four hundred registered speeds, towing
the models at rates varying from one foot to fifteen
feet a second. The dynamometer and towing
apparatus are made to follow the methods evolved
by Froude, at Haslar. and allow tlie model some
small amount of movement while being towed. It
is not possible in the space at our disposal to
describe the electrical measuring apparatus. It must
suffice to sa\' that this apparatus, (so sensiti\'e that
if the length or breadth of the wax model were
altered bv a thousandth part, the resultant alteration
of its resistance would be registered by the dials on
the towing carriage) is fitted with several drums. The
records taken on the main drum consist of time,
distance and resistance. The first of these is given
by an electric clock, which makes and breaks
contact ever\- half second. The distance towed
is measured by a trigger, fitted to the fore girder,
striking against points twenty feet apart, fixed to
the rail sleepers at the side of the tank. This trigger
is caused to swing and so complete an electro-
magnetic circuit. Records of the trim of the model
can be taken, when required, on separate drums.

There are two tanks at Teddington. The Great
Tank (see Figure 4) is of dimensions as follows : —

Length 549-ft. over all.

Breadth 30-t't. on water line.

Depth of water.... IJ-ft. i-in. alont; the middle line.

In the tank walls an oljservation window has been
fitted on either side, about mid-length of the tank.
An arc lamp is to be fitted on one side of the tank
to illuminate the water through the window, so as to
enable a passing model to be obser\-ed under water,
and any phenomena to be photographi^'d.

A smaller tank (see Figure 2). sixt\--four-and-a-half
feet in length, and of five feet width, has been made
for the purpose of in\'estigations with running water.
Experiments can be made in this tank imder two sets
of conditions — either in the still water and the model
being towed : or with the model held on a dvna-
mometer arm and the water made to flow past at
an}- \elocity. For the second of these purposes a
rotary pump has been fitted at one end of the tank,
and provision has been made for reducing eddies.
This pump will give a velocity of about three
iniles an hour to the water, and the ^•elocit\• can be
regulated as desired. Special apparatus has been

designed for castnij.

the wax models — in lengths

varying up to twenty-five feet — and for making
them exactly to scale. The initial programme of
experiments is as follows : —

A standard model will be made to the same lines
as that used at the Haslar Experiment Works, and
the results of the experiments with this model will
be compared with those at Haslar.

Further experiments will be made with (sav three)
models of widely different t\'pes alread\- tried at
Haslar, to ensure the general accurac\- of the
a[i()aratus and methods adopted.

On the satisfactory com[)letion of this work, and
with a view to a series of experiments on mercantile
forms, a preliminary set of experiments will be made
on some typical forms of passenger-cargo and cargo
N'essels having as w ide a variation of block coefficient
and form as possible.

In conjunction with the foregoing, some experi-
ments will be made to test the effect produced on the
diverging system of waves by varying the bow form.
These experiments will start on the lines suggested
by Lord Raxleigh {Phil, .l/.r.t/., September, 1909).

.\s further work to be undertaken at an earh- date,
the Committee have appro\-ed the suggestion to
explore thoroughly the wake in the afterpart of
several typical models. Experiments would be
made to gi\-e the direction of flow, the pressure, and
the velocity head in the streams.

It has also been agreed that it is desirable to
repeat, and, if possible, extend, Mr. W. Froude's
experiments on friction : it is hoped to make
observations on planks up to at least one hundred
feet in length.

ON THE PROPER MOTIONS OF THE FIXED STARS.

Bv W. r)OI?i:KrK, Pir.I).. f.r.a.s.. m.r.i.a.

Halley found that some of the briglitest fixed stars
had changed their places since they had been observed
by the ancient Greeks, and such changes are so
obvious as to be recognised on ancient coins. Sir
\\'illiam Herschel. in 178 J, arrived at the conclusion
that a relative motion of the Sun among the fixed
stars in the direction of a point situated near X
Herculis would account for the greater part of these
proper motions : the motion of the sun towards the
" apex " must cause the fixed stars in half the sk\- to
apparenth" move awav from that point, and in the
other lialf of the sk\- to move towards the
diametrically opposite point, the '" anti-apex."' Since
then a great manv astronomers have determined the
situation of the " apex," but the results do not agree
very well, especially as regards the declination.
Bessel investigated the matter and declared him-
self dissatisfied with the evidence. When the
direction of the proper motion of a fixed star
has been ascertained, a great circle laid through
the positions of the star observed at two epochs is
thereby determined, and if the great circles belonging
to different stars intersect in a point (the apex), it is
easy to see that the poles of these great circles must
lie on another great circle, of which the apex is the
pole. Bessel found that the poles do not lie on or
near a great circle but are scattered over the skw
Kobold, the editor of the Astroiiomischc Xciclirichfen,
who some vears ago took up Bessel's in\'estigations.
proceeds as follows. He imagines the celestial
sphere inscribed in a cube which touches the
S{)here at the two poles and at four points
on the equator. He supposes the eye of the
observer situated in the centre of the sphere, and
any great circle on the sphere is then projected as
a straight line on one or more of the faces of the
cube. Kobold had already used maps made on this
principle in determining radiants of shooting stars,
and the writer had subsequently, in Hongkong, used
similar maps for the same purpose. Kobold projected
the poles of a great number of proper motions on
such maps. Those that correspond to proper
motions intersecting in the apex should lie on a
straight line corresponding to the great circle of
which the apex is the pole, but that is not clearly
shown on the maps.

Kapte}-n, who has the merit of ha\'ing originated
man}- hypotheses that appear destined to aid greatly
in the astronomy of fixed stars, solves the difficulty by
accounting for a great number of proper motions on
the supposition that there are two distinct apices
both close to the galax)-. It had, indeed, in course
of years, become the general impression that the
galaxy is made up not of isolated heavenly bodies
but of a conglomerate of clusters of stars and

nebulae. There was, therefore, nothing extra-
ordinary in the circumstance that the stars
belonging to two clusters did not move in the same
direction. Kapteyn's hypothesis has been examined
at the Greenw ich Observator}- and confirmed there
by the independent evidence of proper motions,
other than those used by Kapteyn. It has been
confirmed also at the Cape of Good Hope. It has
been to some extent confirmed by s[iectroscopic
evidence at the Cape Observatory and at tlie Lick
Observatorw

The speed in miles with which a star is moving
towards or away from the earth can be measured in
the spectrum, the wave-length of the lines being
respectively shortened or lengthened, and it is found
that the stars on opposite sides of the sk\- indicate a
general drift or even two drifts, but the objects used
should be evenlv distributed over the \\hole sk\'. and
the spectra of only few faint stars are known with
sufficient accuracy- for this purpose.

Meantime other radiants have been found. Boss,
editor of the 4s//-o/;o/n/c(T/ Jo»/7k7/, has shown that
the Hvades form a great cluster moving in parallel
lines towards a certain radiant point. .\nother
apparently- (but perhaps only apparentl}-) much larger
cluster, which has been investigated at the Potsdam
Observator\-, contains the stars in the Great Bear,
Sirius and other bright stars.

As mentioned above, the spectroscope enables
astronomers to measure tiie motion of a heavenh-
body in the line of sight in miles per hour. The
proper motion, expressed in seconds of arc, shows
how much it is moving in the line perpendicular to
the line of sight. When the direction of motion in
space is known, then the parallax is at once obtained
from these two quantities, and that direction is given
by the radiant. Parallaxes of fixed stars are more
accurately determined in this wa\' than b\' an\- other
method. Numerous results have been obtained.
Thev show- that the magnitude of a star forms no
guide to its distance from us. Stars of different
intrinsic brightness are mixed in space. Therefore,
it would be no wonder if some of the small telesco[)ic
stars should turn out to be comparatively near the solar
system. Proper motions have hitherto been deter-
mined bv comparing positions recentl\- determined by
the meridian circle with older results. Burnham, at
the Yerkes Observatory, has of late years determined
a number of proper motions by aid of micrometric
measures compared with previous measures made
by Struve, Sir Robert Ball and others. In those
cases where his results differ from the result of
meridian work, the difference is probably caused
bv hitherto unsuspected proper motions of faint stars,
which it will be possible to determine by future

174

KNOWLEDGE.

May. mil.

micrometric measures compared with l>urnham's
observations. At Heidelberg proper motions of faint
stars are discovered b_\' simph' looking in a stereoscope
at photographic plates of the same part of the sky
taken several years apart. Turner has discovered
large proper motions of stars as faint as the eleventh
magnitude marked on photographic plates, and
states that stars with proper motions greater than
15" per centuPi- are scattered with no sensible
reference to the galaxy.

It may be asked what becomes of Herschel's
explanation of the apex caused by the Sun's proper
motion when there are not one but many apices.
It should be kept in mind that all nnjtion is relative,
and it is quite legitimate to attriiiute the apex of the
cluster that contains the largest number of stars to the
proper motion of the Sun. Boss has lateh' discussed
about six thousand proper motions, and he deter-
mines the apex without taking into account the
existence of different s\-stems, and also without
excluding an\- objects.

It appears that all the la. Hants so far fdund lie
near the galaxy, and it is much easier to determine
additional radiants on tin- supposition tliat the\- all
lie near the galaxy, than if the\ were scattered o\er
the sky. If the pole of the galaw is projected on
Kohold's maps, and also the straight line (or rather
lines) corresponding to the great circle of the galax\-.
any straight line from the projected pole to an\- point
on the projected galaxy represents a great circle
perpendicular upon the galaw. and the piojected
poles of proper motions that lie near this line
indicate stars the radiant of whose proper iiiotions
is the pole of the galactic meridian in i|uestion. 1)\-
investigating the proper motions all round the sk\- in
this manner it should be easy to discover all the
radiants that lie near the galaxw

Kapteyn, on the supposition that there are onl\-
two radiants, explains these as being caused bv stars
moving in two diametricall\- opposite directions, and
the fact that they do not appear to be diametrically
opjiosite he explains by combining the proper motion

of the Sun with each of them. In this wa\' the
direction of the Sun"s proper motion is determined,
but it is seen that the Sun belongs to neither of the
clusters. However, there are probabh- more than
two star streams, and there is so far no reason to
suppose that thev mo\e in exactly opposite directions.

It is conceivable that two globular clusters might
attract each other, approach, and pass through to
the opposite side. When the\' had reached the
same di.stance apart on the other side, thev would
stop and their motion would be re\-ersed. The
period of the swing of such a pendulum would
exceed millions of \'ears. But when the enormous
distances between the stars are taken into account
and their relativeh" insignificant sizes, the forces are
found too insignificant to account for existing proper
motions. The energy of runawa}' stars cannot be
derived from attractions between fixed stars or
clusters: it ma\- be due to explosions.

As all observations of heavenb' bodies are made
hv comparison with [Positions of fixed stars, the
accurate determination of the proper motions of the
latter mav be said to be in some sense the most
important object of astronomical observation.
Several astronomers, especialh' Porter in Cincinnati,
have devoted their energies to the disco\-er\- and
determination ot proper motions. An niteniatinnal
coriperation between observatories in all parts ot the
World is being arranged to make a determination
with the utmost accuracy of the positions of a ver\'
great luimber of fixed stars evenly distributed over
the sk\' to ser\e as standards for determining the
positions of faint stars recorded on photographic
plates. But howe\er perfectb' the catalogue
embodxin:; the results of such cooperation ma\'
reflect the ai tual situation in the sk\' of the stars
it contains, it must in a tew \ears become ([uite
inaccurate as the stars change their places, and for
the determination of these changes the catalogue
must rely on observations made in the past, so that
the old observations, far from being superseded, gain
in imiMirtance : and the older the^• are. the more
imriortant it liecomes to take them into consideration.

CORRESPONDENCE.

THE FLIGHT OF BHiDS.

To the Editors of " Knowledge."

Sirs, — The representation by Gatke and others of the
prodigious rapidity of the flight of migrating birds does not
appear to rest on observations bringing conviction. I suggest
that some knowledge on the subject might be obtained. An
amazing number of birds are killed by dashing against
the lighted lanterns of lighthouses. Therefore, I should
suppose that, if on a " fly-line " near the shore there were
placed a dark screen, twenty feet square, and in the middle
thereof there were an aperture of, say, six feet diameter,
covered with such material as that which equestrians jump
through at a circus, and that it were very strongly lighted
from the land side, immigrant birds travelling in the dark
would make for it, and dash right through the flimsy
material. They should then come in sight of another similar
screen three hundred yards away, in the middle of which
should be a disc of strong glass very brightly hglited from

behind. .At this the birds would dash as they do at the
lantern of the lighthouse, and would fall dead — to be
identified and registered by an attendant naturalist. The time
of the first screen being broken by a bird and its death at the
second should be taken by stop-watches. Between the screens
a man should have a camera with which to cinematograph the
approaching bird. There should be a contrivance for
immediatelv replacing the broken flimsy in the first screen.

The birds on reaching the coast might, perhaps, have slowed
down through fatigue, but the bright lights might stimulate
them to renewed exertion.

Years ago, crossing the Channel from France, I observed a
small bird accompanying the steamer for a mile or so. I
could not say pari passu, for it frequently spurted, going
with apparent ease ahead of us and then dropping behind.
The speed of that bird during that flight, till it disappeared,
could hardly have exceeded ten miles an hour.

Some migrants fly high : but the light of a bright screen
might bring some of them down to its level. FRANCIS KAM,

HINTS ON THE PREPARATION OF SKELETONS

OF VERTEBRATES.

i;y J. A. i;ulli;kook.

For the serious study of Comparative Anatom}'
there is nothing better than the preparation of
typical skeletons of the classes and orders of Verte-
brates. It is axiomatic that Morphology cannot lie
learned from te.xt-books alone.

Moreover, though museum preparations are useful
complements to practical study, they cannot super-
sede it. Much can, and must, be learned from the
museum, because the material cannot be observed
elsewhere ; but such study is onl\' superstructure, the
foundation must be laid in the laborator\' or home.

The fascination of preparing and mounting
skeletons of various animals, for study or exhibition,
does not seem to be appreciated h\ either the
student or the amateur naturalist.

Yet, of all practical methods of obtaining correct
and precise information concerning animal structures,
this is certainly the best and probabh' the most
interesting — that is if it is carried out intelligently.

It is possible to prepare a skeleton and yet have
learned very little, or nothing at all. about the real
nature of the animal or its anatom\-.

The work should be done systematicalh' and in
definite order, and never without the aid of gotid
diagrams, or, failing these, a lucid and exact descrip-
tion. To be of any value, the skeleton must be
prepared for use and constant examination, not
merely as a specimen of neat and clever handicraft.

Although this article is intended primarily f(_)r
students, I hope to make it appeal also to the
amateur naturalist, who has, jierhaps, hut little time
and limited means to bestow upon his hobbies.

Now, just in these two particulars, this work is
valuable. It is true that the preparation of a
skeleton takes a great deal of time ; but on the other
hand, the work ma\- be done at odd moments. In
point of fact one is almost sure to spoil a specimen
by working at it too long at a time : the work
requires patience and plenty of it, and will not be
hurried. A long sitting, therefore, is not onl\-
unnecessary but really disadvantageous. As to
expense, all the necessarv instruments and reagents
may be purchased for a few shillings, and the
material, with few exceptions, may be collected by
the enterprising worker at the cost of a little energy
and toil. Indeed, this is one of the charms of the
work, that it entails a stud\- of natural histor\' in

almost exer)' aspect. It is far better to go into the
countr_\- and gather the material hrst liand, so
learning something of the habits and the haunts of
animals, than to reh" on the li\e-stock dealer.
For the convenience of the reader, I have appended
to this article a list of the necessary apparatus and
reagents, with their apjiroximate cost, and a list of
animals which are easiK" obtained and are of most
value for dissection.

Before, however, one can hope to make a satis-
factory preparation, one must spoil some material
and make several practice attempts, both at preparing
and mounting. For these practice attempts, many
advocate using frogs. I, m\'self, prefer the toad.
It is almost as easy to obtain and it has the advantage
that the bones are larger. I have illustrated this
article with the photographs of some skeletons,
including that of the toad ( Biifo vulgaris!. I will
describe first the preparation and mounting of the
latter skeleton, and this will apply to all vertebrate
animals (except fishes) up to the size of a mole or rat.
Larger animals should be mounted articulate or, better
still, put into boxes partitioned for the different skeletal
regions. Thev can be mounted on black boards l)y
using wire, but there is no advantage, and the
specimen then takes up a great deal of space. As
to the preparation of fishes' skeletons, the\' are
imsuitable to any but the advanced student, and will
not be described in this paper.

Now, there are two things, one or both ot \\hich
the beginner is always tempted to do ; either to
burv or to boil the animal, hoping to pick out the
bones clean and just ready to dry and mount. I
never knew of a realh' good specimen being procured
by either of these methods. Moreover, by doing
either, nothing whatever is learned of the soft parts,
and all the meaning of the marks on the bones and
their var\-ing shapes is lost.

The allium! should always be dissected first and
then uiaeerated.

A good description and diagrams are essential.
There are in most places libraries which contain
some books on Comparative Anatomy. It is not
absolutely necessary to have a picture or description
of the animal or its skeleton as a whole, though it
saves trouble, and few text books have such des-
criptions of man\- animals. It is best, therefore, to

175

176

KNOWLEDGE.

May, 1911.

fall back on such books as " .Mi\ai"t's Lessons in
Elementary Anatomy," which contain good diagrams
and lucid desgriptions of the \-arious regions — if not
actually of every animal, at least of so many types
that almost any skeleton ma\' be prepared from
them. I have appended a list of books which will
be of use and easil\- obtained.

To start with the dissection. This is an art
which cannot be taught : it can onh' be learned b\'
patient and plodding labour. The toad should be
dissected carefulh' and thoroughly, with the aid of a
book. .\11 the structures and organs should be
noted, and drawings made at the different stages of
the dissection, especially of the muscles and liga-
ments. When satisfied that the soft parts have
been properly studied, as much of the flesh as
possible is cut from the bones, and the ligaments
are carefully examined.

The body must now be macerated. This process
consists of soaking the bmh- ui water for an
indefinite period. For this i)urpose zinc tanks are
useful (never iron or tin), of the following dimen-
sions : 1-in. long. 3-in. wide, 1^-in. deep, for small

animals: and 6-in. long. 4-in. wide, and i^-in. deep
for larger animals : these shoukl alwa\'S have tight-
fitting lids. A useful substitute. howe\er. is a pie
dish or other shallow earthenware vessel, covered
with a sheet of glass. It is often advisable to
macerate the bod\' in sections, taking care always
to keep together the bones of similar regions.
Esjjeciaily is this method useful with larger animals,
as in this case the quantit\- of flesh one is obliged to
lea\'e on the bones after dissection is often con-
siderable, and b)- putting them into separate tanks
one obtains a larger mass of water to each bone,
and so expedites the process of rotting. The hands
and feet should ahvays be cut off at the joints, and
each macerated separateh' in a small earthenware
or glass jar. While it is macerating, the specimen
needs frequent attention. The vessel should alw■a^•s
be kept covered when one is not actually working on
it, and the specimen must never be allowed to dry uj).

As soon as the bone is loose and all flesh on it is
soft, it is taken out and put aside in fresh water or
preservative (weak spirit or formaldeh\de solution)
after it has been carefully cleaned. I do not advocate
retaining the ligaments. These should be studied in
the fresh condition, unless the object of the
preparation be essentialK- to display them. Should
one wish to keep them, the macerating si)ecimon
will need careful watching, and it must be taken out
of the tank immediateh- when an\- ligaments show-
signs of coming away from the bones. Should anv
flesh still be adherent, it should be scraped oft'
gently with a scalpel. LSut for the preparation in
question, viz. : the toad, the ligaments are not
required. When macerating do not remo\-e too much
of the debris at first, as bv so doing the bacterial
action is liable to lie retarded. After decom-
position has thoi-oughl\- conuueiiced it isad\isable to
take out some of the rubbish from time to time.
For this purpose an old table fork is ver\' useful.

.\s one takes out the bones they must be cleaned.
This is a \er\' tiresome and delicate process.
E.xcept for large bones the knife should not be
used. A camel-hair brush, an oil-painter's flat
bristle brush with the bristles cut down to about a
quarter of an inch : a couple of needles mounted in
handles : a pair of fine forceps ; and a pair
of fine-pointed scissors, cur\'ed on the flat, are
the necessar\- instruments. An\- stubborn fibres
of ligament should be cut off close with the point of
the scissors ; the flesh and debris are brushed off with
the hard brush, and the bone is finished l)y brushing
with the soft brush. The brush should always be
used in one direction onl\-, not to and fro. The
bones should ah\a^•s be held in the forceps — never
in the fingers, and the w hole cleaning should be done
as far as possible under water. A piece of ground
glass, made to fit the bottom of the cleaning vessel
and with its smooth surface blackened w ith jiaint, so
that the colour shows dull through the ground
surface, is very useful as the bones show up clearly
upon it when one is cleaning them. If after cleaning,
some pieces of flesh still adhere tightly to the bones,
tlie\- must be macerated further.

It sometimes happens that the ligaments will not
\ ield to maceration : especially is this the case with
the hands and feet of all vertebrates and the
vertebrae of Ophidia. In this case boiling becomes
necessarw The bones should be boiled in a small
enamelled saucepan, the smaller the better. Before
putting thi-m into the saucepan, a few drops of strong
solution of caustic potash ma\- be added to the
water ; ver\- little should be usetl and the potash
should never be added in solid form, because it
takes some time for it to diffuse and the specimen
is liable to injur\' through coming in contact
with a \er\- strong solution. The liquid potash
should be added to the water, droj) by drop,
and the whole well stirred before putting in the
bones.

The ligaments will often soften b\- just bringing
them to the boil, and the specimen must ne\-er be
boiled for more than a quarter of an hour. It is not
ad\'isable to boil the bones clean ; they should be
cleaned, in the manner mentioned above, after
boiling.

The next process after cleaning is bleaching.
\Mien all the bones are clean they should be washed
free from any preservative — if such has been used —
with distilled water. They are then placed in a
glass vessel in a 1 in 20 solution of hydrogen
pero.xide. The strength is made by mixing the
strong solution ordinarily sold, with 19 parts water.
This does not of course represent 1 part H, O2 in 20
of water. The vessel containing the bleaching bones
shLiuld always be kept co\-ered with a sheet of glass
so that no oxygen is lost. Never use chloride of
lime for bleaching as 't injures the bones and
destro\'s the markings.

The vessel should be broael and shallow so as to
obtain the greater surface area, and it should be
[jlaced on a white surface so that the light is rellected

May, 1911.

KNOWLEDGE.

177

fairlv equally on to all parts of the bones. The bones
are whitened more quickh' b\' adding a few drops

Figure 1. A Skeleton of a Toad 'B;(/o rw/garis/.

of caustic potash to the peroxide solution, but this
should onlv be done with the larger bones, as the
small ones absorb a good deal of the caustic and
rapidlv turn \ellow after mounting. In any case
very little potash must be used or else tubercles
and other markings will be obliterated. Hydrogen
peroxide is harmless, but caustic potash is not. The
bones should all be placed in the same strength of
bleaching solution and remain in it for the same
length of time, i.e., until all are whitened. But it is
advisable still, and indeed throughout, to keep the
hands and feet separate from the rest, each being
prepared in a separate dish.

After bleaching, the bones should be washed care-
fully again in distilled %\ ater; anv debris still adherent
maj" be taken off w ith a soft brush and the bones
thoroughly dried. For this purpose a few racks are
required. For larger bones these are best made

of what is known as expanded metal, i.e.. iron sheet
stamped through with slits and then drawn out into
diamond-shaped net-work. Squares of this material
are nailed on at the sides to wooden blocks, this
form of rack allowing the air to circulate freel\- all
round the bone. The iron should be covered with
-ome hard enamel to prevent the bones being
injured by rust. For small bones, a porous earthen-
ware plate such as is used by chemists for drying
crystals, is best, although blotting paper will
serve the purpose. The bones should be picked out
cine by one — not shot out promiscuously — and left to
dry for at least twenty-four hours. Should any
debris resembling bones remain in the solution, a
slight pinch with the forceps \v\\\ always indicate
their true character.

There now oiih' remains the mountihs- This

FiGUKt -..

A Skeleton of a Love Bird ( Androglussiiia agaponiis).

1?8

KNOWLEDGE

May, 1911.

sliould he done as far as possible at one sitting. The
bones should be taken and arranged on a card.

O

or, better still, on the blackened glass sheet, in their
respective natural positions, the different regions
being spaced distinctly. The skeleton should be
mounted in a similar fashion on stiff" card which has
first been carefully blackened with a dull pigment
(such as ivorv black) as seen in the illustrations, and
thoroughly dried. A good method is to paint red lines
around or between the different regions. I would
advocate mounting all one's skeletons on the same
plan, and I think that the best is that shown in the
accom[>an\ing figures (1 and 2). It is mapped out
thus: —

Lower Jaw

and
Hyoideal

Face

and
Cranium.

Hand. I'ore limb. Pectoral Girdle. Fore limb.

Hand.

C
e
r

V

i
c
a
1

t
o

S
a
c
r
a

V
e
r
t
e
b
r
a
e

C

a

F Hind limb. Hip u Girdk-. Hind limb. F

o d o

o a o

1

V
e

r
1
c
b
r
a

The bones on cither side are to be plared show iiig
inferior and superior surfaces respectiveh-, so as to dis-
play the various markings, and so on. The mounting

is done with a fine camel-hau- brush dipped in
benzol solution of Canada balsam. This should not
be too stiff or a skin will form before the bone can
set : nor must it be too thin, or it will soak into the
bone and discolour it. In mounting the bone, it is
held in position abo\e the card by the forceps, and
the brush is drawn over the card so that it leaves a
film of balsam as near the shape and dimensions of
the bone as possible, on which the latter is then
dropped. (_)nlv sufficient balsam should be used
to ensure the bone remaining on the card,
and care should be taken not to soil the forceps
with the mucilage, or the marks of the bones may be
masked. The specimen is now placed in a box into
which the card fits exactly, and is kept in a horizontal
position. The preparation is now complete save for
the dr\'ing of the balsam, which takes a week or
two.

Regarding the jireparation of skeletons of larger
animals, little need be added to what has already
been said. The bodies may, however, be boiled
with less risk, and both in cleaning and bleaching,
caustic potash may be used at discretion. A tooth
brush and nail brush are necessary for cleaning, and
the knife may be used more free!}-.

The mounting, however, of larger preparations
differs considerablv from that ahead}' described.

The bones, except the vertebrae, hands and feet,
should be left loose. Those of the hands and feet
should lie mounted on black cards, unless they are
large, when they should be bored and strung on
catgut in their proper positions. The best instru-
ment for boring is a "fiddle drill" such as is used
1)\- jewellers. The skeleton should be kept in a
box and di\iileil up into regions as before, each
region being placed in a separate partition for easy
reference.

For larger animals, it is useful to keej) twn skulls,
one articulate and one disarticulated. To dis-
articulate the skull, it is first cleaned, and all the
brain matter removed with a scoop. The cranium
is then filled through the Foramen Magnum with
raw rice or dried peas, according to the size of the
foramina in the skull, and the Foramen Magnum
plugged tightly with a cork. The whole is then
placed in cold water in a saucepan and boiled until
the grain, by swelling, has forced the bones apart at
the sutures. The bones are then taken out, washed
and bleached.

It is sometimes useful to keej) cartilaginous
structures. To retain these in their original shape
is difficult, in fact, almost impossible. The most
satisfactory method of preparing them is to dissect
them : clean : place in good methylated spirit for
twehe hours : soak in moderately thick solution of
Canada balsam for at least three days : and then
allow them to drv hard.

1 \\:i\v purposely refrained from any description
of the methods of articulating skeletons. This work
would require an article to itself, and is unsuitable
to the beginner.

May. 1911.

KNOWLEDGE.

List of Animals sitfable for Skflktoxs.

Raiia tcmponiria (frog) ...
Riifo vulgaris itoad) ...
Triton crisfatns (crested newt) ...
Laccrtti I'ifipcim (^'rass lizard) ...
Tropidonotiis iiatrix (common

snake) ...
Sfiirniis vulgaris (starling)
Mits dccuinanns (rat)
Talpa ciiropca (mole)
Erinacfiis curopciis (hedgehog) ...
Canis faiuiliaris (dog) ...
Felis cioiiicsficus (cat) ...
Sciuriis vulgaris (sf|uirrel)
Ccrcopifhccus callitrichus (green

monkey)

Batrachian.

do.
Tailed Batrachian.
Lacertilia.

Ophidia.
.•\ves.
Rodentia.
Insectivora.

do.
Carnivora.

do.
Frugivora.

Anthropoid monkeys.

List of Books.

Lessons in Elementarv .'\natoniy
Osteology of Mammalia
Comparative Anatomy
Practical Zoology ...
Manual of Zoology ...
Te.\t-book of Zoology
The Cambridge Natural History

St. George Mivart. M.D.

W. H. Flower. F.R.S.

W'eidersheim.

T. J. and \\'. N. Parker.

H. A. Nicholson.

T.J.Parker&W.Haswcll

List of necessary Appar.vtu^
AND Reagents,

Fiddle drill and drills

Dissecting forceps ...

Fine forceps

Double-spooned brain scoop

Two needles in handles

Dissecting scissors ...

Fine-pointed scissors cur\cd on the flat .

Two scalpels

Glass jars

Porcelain developing dish (] -plate)

Glass covers...

Glass dishes with covers ...

Drying racks

do. plate...
Watch glasses
Blackened glass
Zinc tanks ...
Hydrogen peroxide (20 Vols.)
Potassium hydroxide (sticks)
Methylated spirit
Carbolic acid (crystals)
Formaldehyde solution (40 %)
Canada balsam (in benzol)

179

Instri'ments

3s. 6d.
U. 6d.

''xl.

yd.

each.

IS.

Is.
3d.
Is.
Is.

Is.
Id,
Is.
Id,

rxl

6d.

fid. each.

each .

d. each,
each.

and .

to 2s
2d. each.
Is.

Id. each.
4d.

Qd. to 2s. each.
2d. per oz.
Is. per lb.
4d. per pint.
2d. per oz.
4d. per oz.
4d. per oz.

SOLAR DLSTURBANCE.S DURING M.ARCH, 191 1.
By FRANK C. DENNETT.

There was a slight increase of activity upon the Sun's
surface duriug March, and the repetition of outbreaks upon, or
close to, the site of pre\'ious disturbances was very marked.
The disc appeared free from disturbance on March 6th, 15th,
and 17th, and only faculae were observed on lith, I4th, ISth.
19th. 20th, 2Ist, 22nd, 26th, and 27th. The longitude of the
central meridian at noon on March 1st, was 237' 34'.

No. 3 remaining visible until March 5th is shown on the
chart.

No. 6. — A group of pores, a leader with some tiny com-
panions in front, with a larger pore bringing up the rear.
The group was 39,000 miles in length, and remained visible
from the 2nd until the 5th, and on the 7th two black pores
were seen close to the same place.

No. 7. — .A pore amid faculic S(n'roundings only seen on
March 5th.

No. 8. — A small spot came round the eastern limb, and
continued visible from the Sth until the I2th.

No. 9. — .\ pair of pores about 37,000 miles apart, in a very
bright faculic disturbance, marking the site of No. 6, seen on
the 10th and 1 1th of March.

No. 10. — .\ solitary pore seen only on the I6th.

No. II. — .-Xnother single pore with faculae around it, seen
only on March 24th and 25th.

No. 12. — After the disappearance of No. 5. The site was
marked by a fine faculic disturbance as it approached the
limb on the 9th and 10th. It was found on the 26th to have
come round the eastern limb, and on the 28th a group of four
black pores had made their appearance in the group. On the
3 1st there was a considerable spot as leader, and another as
trailer, with some pores between them. On April 1st, the
leader was preceded by a tiny pore, and the whole of the
group following the leader was made up of pores, the rear
ones partially outlining an ellipse. On the 4th there was seen
to be a black hydrogen flocculus close to a pore, east of the
leader, and the pore seemed to increase in size. When just
within the limb on the 6th, the leader, which alone remained
visible, appeared to be increasing in size. The leading spot
attained a diameter of 15.000 miles, and the group a length
of 83.000 miles.

The chart is constructed from the combined observations of
Messrs. J. McHarg, A. \. Buss, E. E. Peacock and the writer.

DAY OF .ALARCH.

S

I? le )/ 16 1,5 14 1^, 1^ I,) ip 9 ? T t ^. <, ?l. Z,^l> l,p.\p 2j 26 gS 2f 23 ^g. ^1 ^0

a ,0

T~r

B

¥

IFCD

u

0 10 20 30 40 50 60 70 80 90 100 110 120 )30 (40 ISO 160 l/"0

260 270 280 290 300 310 320 J30 340 350 360

THE FACE OF THE SKY FOR MAY.

Bv W. SH.VCKLETON. .\.R.C.S., F.R.A.S.

The Sr\. — ( )ii the 1st. the Sun rises at 4.35 and sets at 7.19 ;
on the 31st he rises at 3.51 and sets at 8.3. Sun-spots and
faculae may usually be seen on the solar disc, but spots are
small and not numerous. The positions of the Sun's axis,
equator, and heliographic longitude of the centre, of the disc
are shown in the following table: —

V'enus:-

Date.

.^xis inclined
from N. point.

Centre of Disc

S. of
Sun's Equator.

Meliogiaphic

Longitude of

Centre of Disc.

Mav I

24" 22 '\V

4° 6'

152° 46-

,, 0 ...

23° 24'\V

f 35'

86° 4 1 '

., II ..

22° i6'\V

3° 2'

20° 34'

,, i6 ..

20° 58 '\V

2° 29'

314° 26'

,. 21 ...

19° 29'\V

1° 54'

248° 18'

,, 2(] ...

17° S2'W

1° 19'

182° 9'

., 31 ...

16° 5'W

0° 43'

115" 59'

June 5 ...

14-^ n'W

0° 0'

40 49'

The Moon :-

Date.

Phases.

H. M.

May 5 ...

„ 13 ...

,, 21 ...

,, 28 ...
June 3 ...

1) First (Quarter ..

0 Full .M.Min

(I Last <Jnarter ...

• N.« Moon

]: f irst 'J'uirier ..

I 14 p.m.
t) 10 a.m.
9 23 a.m.
6 24 a.m.
10 4 p.m.

Mav 15 ...

,,' 28 ...

June II ...

Apogee ...
Perigee ..
Apogee

6 48 p m.

5 24 p.m.

10 42 p.m.

There is a Penuinbral Eclipse of the Moon on the morning of
the 13th. but since the Moon sets before the middle of the
eclipse and only passes through the penumbra very little can
be seen. The following are the particulars; —

May 13th.
First contact with the Penumbra i^ 46" a.m.

Middle of the ecHpse 5" 57'" .i.m.

Last contact with the Penumbra «'' 7™ a.m.

The first contact occurs at 65° from the North point of the
Moon's limb towards the East. The Moon sets at Greenwich
at 4'' -7"" a.m.

Occui.T.ATlONS.— No naked eye stars are occulted and
visible froin this countrv during the month.

THE PLANETS.

Mercury :

Dale.

Right Ascension.

Declinalion.

May I ..

,, II ...

21

li. 111.
2 55
2 35
2 31

N 18° 11'

13' 48'
11° 26'

June 1 ...
„ II ...

2 57

3 44

13° 6'

N 17- n'

On May 5th, Mercury is in inferior conjunction with the
Sun and therefore unobscrvable. Towards the end of the
month the planet is a morning star in .\ries rising at 3.11 a.m.
on the 31st. On June 1st the planet is at greatest westerly
elongation from the Sun of 24 30'. The planet is in con-
junction with Saturn on the 29th May, at 3 a.m.

Date.

Right .-Vscension.

Declination.

h. m.

Mav I ...

5 0

N 24' 25'

II ...

5 5'

25° 29'

21 ...

6 42

25° 21'

June I

7 30

24° o'

,, II ...

8 ^i

N 21° 42'

Venus is a brilliant object in the evening sky, looking N.W".
by W. immediately after sunset.

The planet is well placed for observation, appearing high
above the horizon at sunset, and not setting till 11.15 p.m. on
May 14th, and 11.22 on May 31st.

.\s the distance from the Earth diminishes, the apparent
diameter of the planet increases, and is now about 16"; later
in the year, when the planet appears still brighter, the diameter
increases to over 40"

The planet can readily be seen with the naked eye long
before it is dark, and a telescope of only 1-inch aperture is
sufficient optical aid to find it in broad daylight when directed
to the correct position in the sky,

.■Vs seen in the telescope, the planet appears gibbous, 0-7 of
the disc being illuminated ; broad daylight is the best time for
observing, and with magnifying powers of 150 to 250 on 4-inch
or 5-inch telescopes shadings may be seen on the planet's disc
on the terminator side, the limb appearing intensely brilliant.
The Moon appears near the planet on May 1st, and on the
30th. conjunction takes place with .Neptune.

M.\KS : —

Date.

Right Ascension.

Declination.

May I ...

,, II ...

., 21 ...
June I ...

.. u ...

h. n,.

22 34
-5 2

23 29
23 59

0 26

S 10° 45'

8° 3

5° 16'

S 2° 10'

N 0° 38'

Mars is a morning star, rising E, by S.. about 2.20 a.m..
near the middle of the month. The apparent diameter of the
planet is only 6"- 5. This is too small for useful observations
to be made ; towards the end of the year, however, the planet
is in opposition, and the apparent diameter will then be three
times the above amount.

Jupiter : —

Date.

Right Ascension.

Declination.

li. ni.

Mav I ...

14 31

S Ij 3 J

,, II ...

14 26

13° 0'

,, 21 ...

14 21

12° 39'

lune I ..

14 17

12° 19'

II ...

14 14

s 12° -■

Jupiter is in opposition to the Sun on May 1st, and hence at
this time he appears on the meridian at midnight, and, more-
over, he then appears at his brightest.

180

May. 1911.

KNOWLEDGE.

181

The planet is a very conspicuous object in the e\ening,
looking S.E.. rather low down; on May 1st he rises at 7.2 p.m..
and throughout the month he has risen in the E.S.E. before
the Sun has set.

The planet is describing a retrograde path near the star
X Virginus.

On account of the belt markings on the disc, and his bright
satellites, this is the easiest and most interesting planet to
observe in small telescopes. The polar flattening is .also a
noticeable feature, since the equatorial diameter is 44" and the
polar diameter 2"-S smaller.

The Great Red Spot has been difficult to observe during the
past few years, but the period deduced from observations ot
the spot give the planet's rotation as 9*^ 55"" 38*.

The rapidly moving satellites present a diversity of con-
figurations in the same evening ; the following table gives
their principal phenomena observable before midnight.

Uranus :

c

u

O

i P.M.'s.

V

0

E

0

r.M.-,.

"5

0

0

H.M.V

d

X

CU H. .M.

C

X

-

M. M.

H

■r.

-

H. M.

May

;

I.
11.

Oc. 1). 8 55
E;. R. 9 14

May

16
16

Tr.

Sh.

I- 9 35
I- 9 57

May
24
24

III.
II.

Sh.
Tr.

I. 10 7
E. 10 ;8

I

1.

Oc. R. II 5

16

Tr.

E. 11 46

24

Ec.

R. II 15

1.
II.

Sh. E. 8 20
Oc. D. 8 55

17
17

'!:

Sh.
Ec.

E. 9 10
R. 9 21

24
24

11.

III.

Sh.
Sh.

E. II 44
E. II 45

1.

Oc. D. lo 38

2>

Tr.

I. II 20

31

Oc.

I). 10 18

s

]l.

Ec. R. 11 51

23

Sh.

I. II 51

31

11.

Ir.

I. 10 20

0

I.

Tr. E. 10 I

24

II.

Sh.

I. 9 8

31

111.

Ir.

1. II 26

9

I.

.Sh. E. 10 14

24

111.

Ir.

E. 9 21

31

11.

Sh.

I. II 42

"

11.

Oc.D. II II

" Oc. D." denotes the disappearance of the Satellite behind the dibc, and
■ Oc. R." its reappearance ; '*Tr. I." the ingress of a transit across the disc, and
** Tr. E." its egress ; "' Sh. I." the ingress of a transit of the shadow across the disc,
and "Sh. E." its egress; " Ec. D." denotes disappearance of Satellite Iiy Eclipse,
and " Ec R." its reappearance.

Saturn : —

Date.

Righl Ascension.

Declination.

May I ...

.: 17 ...

June 2 ...

ll. ni.

2 32
2 40
2 4ti

\ 12" 43'

13" 21'

N 13° 55'

Saturn is in conjunction with the Sun on May 1st, and
therefore unobservable during the early part of the month.
Towards the end of the month the planet is a morning star,
rising in the E.N.E. at 3.34 a.m., on May 21st.

Dale.

Right Ascension.

Declination.

May I ...
June I ...

ll. m. s.
20 6 29
20 5 M

S 20'' 49' 7"
.S 20^" 53' 49"

Uranus rises about midnight on the 20th May, and
about 11,18 p.m. on June 1st. The planet is Uiifavourably
placed for observation as he is low down in the sky : he is
describing a retrograde path in Capricornus about 2 S.E. of
cf Capricorni,

Neptune : —

Date.

Righl Ascension.

Declination.

May I ...
June I ...

h. in. s.
7 22 5
7 25 1 5

N 21° 30' 19"

N 2U' 24' 49"

Neptune is observable in the N.W, portion of the evening
sky, not far from Venus, and is in conjunction with that planet
on the 30th. The planet sets at 11.50 p.m. on the 15th.

The planet is difficult to identify among the numerous small
stars appearing in the same field of view, as it requires a high
power (about 300) and good definition to distinguish his disc ;
he can, however, be detected by his relative motion if
observation be made on successive nights.

Meteor Showers : —

The principal shower during May is the Aqiiarids. This
may be looked for between May 1 to ft : the radiant being in
R.A. 22" 32" Dec. S. 2 . near the star v Aijuarii.

Telescopic Objects: —

Double St.\rs.— a Librae, Xl\"." 46'". S. 15 40', m.igs. 3,
6 : separation 230" ; very wide pair.

ff Coronae, XVI.'' ll", N. 34' 8', mags. 6, 6i ; separation
5"-0; binarv.

a Herculis, XVII." lo'". N. 14 30', mags. 2.1, 6: separation
4"- 8. Very pretty double, with good contrast of colours, the
brighter component being orange, the other blue.

S Herculis, XVII.'' 11"". N. 24 57'. mags. 3. 8: separa
tion 14".

Clusters. — M13 (cluster in Hercules) is situated about
one-third the distance from -q to s' Herctilis, and is just visible
to the naked eye. It is a globular cluster, and with a three or
four inch telescope the outlying parts of the cluster can be
resolved into a conglomeration of stars.

QUERIES AXD .ANSWERS.

Readers arc invited to send in Questions and to ansu-er the Queries which arc printed on here.

QUESTIONS.

35. MOVEMENT OF A TAUT WIRE.— \\'hen a taut

wire, say a mile long, has a weight at one end and one pulls it

a foot towards one at the other, does the distal end of the wire

move at the same time .as the proximal in one's hand, or is its

movement later ? t- r>

Fr.\ncls R.\m.

36. METEORS. — It is stated in most buoks on .\strononiy
that meteors are ignited by friction with our atmosphere at a
height of seventy miles sometimes. As the density at
this height does not amount to nearly the millionth of that at
sea level, can any of your readers explain how falling bodies

could be ignited by such a rarefied atmnsphere,
that they move at the rate of forty-fi\e mile
maximuiTi speed for meteors ?

even assummg
i a second, the

' Puzzled."

37. ROTATION OF STUFFED BIRDS .\TTACHED
TO WIRES.— The little birds, which are suspended by wires
in a case in the hall of the Natural History Museum, may be
observed very slowly to rotate, the tips of their wings describing
a quadrant of a circle, or more : and so they have done, I can
aver, for the last twenty years. What is the cause of the
movement? Fr.^ncis R.^m.

182

KNOWLEDGE.

Mav. 1911.

38. THE EFFECT OF GR1:AT ALTFIUDES ON
THF..ARS. — Is it true that persons ascending mountains
experience, on reaching great altitudes, bleeding of the ears ?

If so, would not this bleeding be beneficial to persons
suffering from any congestion of the ears ■

Thirdly, could an atmospheric condition similar to that
which obtains at great altitudes be produced on the sea-level
by any scientific process ? p t,

i9. ANTI-CVCLONE.— I should be much obliged by your
favouring me with an explanation of the term " .Anti-Cyclone."
I have always understood it meant the opposite of Cyclone,
viz., a perfect calm. This I have had disputed, and that the
storms we have lately had from the Easterly have been caused
by an '" .\nti-Cyclone." Now, if .Anti-Cyclone and Cyclone
both mean storms. w-h\- the prefix ".Anti"? Some of the
books I have, merely, give "Cyclone," but do not mention
" Anti-Cyclone." or if the term is referred to, it is only in a
very \'ague wa\', and the language is by no means plain or

e^P'''"'^*'"'-^'- Wm. S. Jeffery,

40. WATER-FINDING.— The other day. Mr. Pogson, a
well-known water-diviner of Madras, located as many as six
subterranean springs in a garden in Cuddalore, India, Wells
were sunk at all the six spots, and. strangely enough, water
was found in all of them at very nearly the same depth, and
in approximately the quantity calculated by the diviner.

Like all other water-finders, Mr. Pogson locates water by
means of an ordinary rod — either of wood or of metal —
which, without any volitional effort on his part, spontaneously
rotates in his hand when he stands above a bed of water
underground, or points vertically downward if he happens to
be over a spring of small dimensions, I should be very
much obliged if a scientific explanation can be gi\en of this
wonderful phenomenon.

It mav be well here to point out that Mr. Pogson is also
endowed with magnetic susceptibility, by which he can tell
wliich pole of a bar magnet is turned to him. Hallcy's comet,
he sa\-s, affected him before and after its perihelion passage,
exactly like the North and South poles of a magnet.

T. K. Joseph.

REPLIES.

10. WATER AND ITS OWN LEVEL.— The real mean-
ing of the common expression that water finds its own level is
identical with that of Mr. Yerward James (" Knowledge,"
March. IQll, page 103) that it seeks its " Appropriate Spherical
Cur\ature." What he says about the variation in the surface
of a cup of tea when lifted may be true, but there are so many
influences in operation that it might take a little time for the
fluid to adjust itself, the motion of lifting having some action
besides the effects due to inertia, capillarity and friction. So
the centre of gravity of the earth is affected by any displace-
ment of particles on the surface of the earth, such, for instance,
as when a boy throws a stone, or when a crane lifts a mass of
rock, or when a ship takes a cargo of coal from one place to
another.

As regards experimental proof of the convexity of the surface
of water, reference should be made to the experiment tried on
the Bedford Level Canal, a straight piece of water six miles
long. This e.xperiment w-as fully reported in The Field
newspaper, March and .April, 1870, and might be considered
proof conclusive of the con\exity of the surface of water.

Lumen Marti.wum.

30. FINDING THE TIME, BY DAY.— (11 Local apparent
time can be roughly found when the ratio of the length of an
upright stick to the length of its shadow is known, by using
the following method : —

Taking the data given by " Interested," and the angles to
the nearest degree of arc, we have latitude = 52° and Sun's
declination on the given day=15' North. Call the length of
the stick unity: then in the right-angled triangle whose
perpendicular and base is the length of the stick and shadow
respectively, we must find the angle .ABC. In the given case
(shadowtwice the length of thestickl tan "' J =27" = angle CAB

which is the altitude of the Sun above the horizon at the time
the measurements are taken. It will now be necessary to find
the uorthmost angle of a spherical triangle on the celestial
sphere, three sides of it being given, viz. (90° — Sun's altitude)
or Sun's zenith distance, the Sun's angular distance from the
north pole of the heavens, and the colatitude of the place.
Using the formula

' — 'cos s, sin (s — a)

sin ^-y ^

cos 1. sin p,

where P is the angle required (being the Sun's angular distance
from the meridi.an and therefore equal to the time), a the
altitude of the Sun, / the latitude of the place, p the Sun's
polar distance, and s half the sum of the three last mentioned
quantities, the times deduced are either 7'' 44™ a.m. or 4'' lb""
p.m., the shadow in this particular case having the same
length twice during the day. This process, by the way, is

2e.,vtf^

pie. n V

similar to that used to find time at sea except that .i sextant is
used to measure the altitude of the Sun instead of the ratio of
the length of a stick to its shadow.

(2) In the latitude of London the length of a perpendicular
stick is equal to the length of its shadow at noon at about 9th
April and 5th September of each year. The reason is
apparent from a study of the figure. With the sun on the
meridian and with the stick and its shadow of equal lengths we
have, by elementary geometry, the angle .ABC = 45', which
must be the altitude of the Sun at noon. Now the colatitude
of London is about 38 (see Figure D so that the Sun will
require to have a northerly declination of 7' to make its
meridian altitude = 45 and the Sun's declination has such a
value on the dates mentioned.

(3) The latitude of any place can be found, if the ratio of
the length of the stick to its shadow at noon is known (the
Sun's declination being also known approximately), for by the
first answer the altitude of the Sun can be found from the
given data, and by the figure it is seen that the latitude when
the Sun is north of the celestial equator is equal to its zenith
distance {i.e.. its altitude subtracted from 90^) added to the
northerly declination, and when south, the latitude is equal to
the Sun's zenith distance minus the southerly declination.

Xote. — In the figure the length of the stick is drawn out of
all proportion to the other lines. The stick, if drawn to scale,
would require to be represented by an infinitesimal line on an
infinitely small earth situated at the centre of the celestial
sphere, half of which is shown. ^^^^_ ^ ^^^^^^_

30. To find the time of the day by comparing tlie ratio
between the length of a stick and that of its shadow involves
the solution of a spherical triangle.

The fornmla for determining the hour angle is as follows: —
sin — = A^/ f cos H0 + -^ + °) sin i (0 -f A - "^ \
^ ^ \ cos <p sin A )

where 0 is the latitude, A the polar distance of the Sun. or
90 - declination, a the altitude, and /; the hour angle.

May. 1911.

KNOWLEDGE.

183

If the ratio of the length of a stick to that of its shadow-
is i, the tangent of the angle of elevation is -5. and a = 26 34'.
Now, on Mav 1st the Snn's declination is 14' 49' N.. or
A = 90 - 14° 49' = 75' 11 '.

h'lGUKE 1.

0, the Latitnde of London is 51° 31' iiearl\
Making these snbstitntions we find that

2

■5436

— = 32° 56' nearlv.
2

/( = 65° 52'
= 65- -866
Hence, the number of honrs before or after the Sini has
crossed the Meridian is

65-866 „ , ,„
— - _ 4-39

or 4". 23"\
Hence the time is about 7.37 a.m. or 4.23 p.m.

The Sun will attain nearly the same declination on
August 13th, so that the same ratio between the length of a
stick and that of its shadow would hold at the above times on
this date.

To solve the second part of the (|uestion, finding the dates
when the length of a stick and th.it of its shadow are eipial at
noon in Latitude London, we have the well known equation

Colat. + Dec. = Meridian Altitude.

Where Colat. = 90 - Lat. = 90 - 51 31'
= 38° 29'

In this case M.A. = 45°, since the tangent of the angle of
elevation is 1.

Hence Dec. = 45' - 38' 29' North.
= 6° 31' N.

The Sun attains this Declination about April 7th and
September 7th. On these two dates, therefore, the length of
the shadow will be equal to that of the stick at nomi. in
Latitude of London.

To find the Latitude, assuming we know the ratio between
the length of a stick and that of its shadow at noon on
April 20th.

Suppose a stick 7-ft. 1-in. high cast a shadow (i-ft. long at

noon.

85
If a be the angle of elevation, tan a = - —

72

= 1-1805. .■. a = 49= 44'

Now. on .April 20th, the Declination of the Sun is IL 13' N.
Colat. + Dec = Meridian Altitude.
.-. Colat. = 49° 44' - !!' 13'
= 38= 31
Hence Latitude is 90° - 38° 31'

= 51 29
or, about the Latitude of London.

On August 24th, the Sun attains nearly the sauie declination,
so that this ratio would hold on that date also. It should be
noted that the time found in the first part of the question will
be apparent time. The mean time, or clock time, is found
from it by the equation. Mean Time — Apparent Time =
Equation of Time. As, however, the equation of time is never
more than sixteen minutes, there is no considerable error in
taking the two as coinciding. On none of the dates given
above does the equation of time amount to five mimites.

IRhV.I M. D.winsnN.

30. In answer to (Question 30, of "Interested" (March issue of
2 " Knowledge ■'), may I suggest

^ I the following aspossiblesolutions

to the queries therein mentioned?
(1) How can the time of day
be ascertained by measuring the
ratio of the length of a stick
to that of its sh.'idow on a given
date ?

In Figure 1, OT represents
the stick. O A the length of
the shadow of the stick cast by the Sun, OZ the zenith.
Then

tan-' OA
OT
In Figure 2, E H W is the horizon, l:
equator, P the celestial pole, / the zenith.

S Z = Sun's zenith distance (found
by means of the stick).

ZF = Colatitude -= (90' - 51° 30')
= 38° 30'. (If London is the place
of observation).

S P = Sun's North Polar distance
= 90° — Sun's Decl. (found from
almanac on given date).

< S Z M = Sun's Azimuth, i.e..
Sun's angular distance from Meridian
measured from the north point,
through E S H W".

Then from Spherical tri
Sin^PZ ^ Sin SZP
SP

Figure 1.

Sun':

zenith distance at instant of
observation.

Sin SZ

Sin

^leSZ P.
Sin S P Z

Figure 3.

Sin SZP
Sin S P

and this gives the Sun's Eastern

or Western hour angle according

as the observation is before or

after noon. If the observation is

before noon, 12 — Sun's hour angle

gives the approximate time. If

after noon the time is gi\'en by

Sun's hour angle alone.

(2) .At what times in the year will

same as that of its shadow at noon ?

the length of stick be the
(Latitude of London.)

When the length of shadow equals length of stick the Sun's
zenith distance is then 45° and 51" 30' - 45°, gives the Sun's
declination at the required times .'. Sun's Declination = 6" 30 .

I'rom the almanac we find that the Sun's declination has
this value on the 7th April, and the 7th September.

(3) Can the latitude of a place be determined by comparing
the ratio between the length of a stick and that of its shadow
at noon ?

Sun's zenith distance at noon

length of shadow
length of stick

Sun's Declination - < O O S, (E Q W represents the equator!
(P the pole) and < OOZ = Latitude required.

Latitude=< SOQ+<SOZ. L. O. G. P.

-= tan

<zos

A

NEW LICHEN, GONGYLIA VIRIDIS A.L.Sm.
IN SURREY AND ESSEX.

r5v ROBERT PAULSON,

.R.M.S.

A Ni-:w liclK-n ^Towinj,' on the sandy bank of a foot-
path in the neighbourhood of Horsle\', Surrey, and
named by Miss A. Lorrain Smith. Gonfiylia viridis.
was first collected by Mr. B. W. [. Starling, in
Februar\', 1910. Since
that date it has been
recorded hv Mr. Percv
Thompson from three
separate localities of
Epping Forest, all in
the vicinitN' of Loughton

It
re-

^athered
spot in

and Theydon Bois
has again, quite
centl\'. been
from another
Surrey, by Mr. .Starling.
The finding of this
lichen in Epping Forest
was not a result of the
discovery in Surre\-, as
it was sent for identi-
fication with other
material that hail been
collected, both at the
Esse.x Field Club Lichen
and Moss Fora\' held in
November last and at
periods previous to that
date. It was, most
probably, first collected
in the Forest in April.
1910.

There is little matter
for surprise that this
plant has hitherto been
overlooked, for its thin,
green, crustaceous
thallus grows upon the
ground and takes, as it
spreads over the surface,
all the irregularities of
the soil. To an\one
standing erect it appears
as a green discoloration
of the ground similar to
that given by algae in
damp places. It might
easily be passed over,
when not fertile, as the
immature thallus of
Boeomyces roseiis. The

sand\- bank at

Horsle\'

has a southern aspect, so that the plant is fullv
exposed to the sun, there being little or no shade
there. In Epping Forest this lichen occurs on
sandy soil around gravel pits, and in one case it is
on the perpendicular face of the digging, but all the
Forest localities are more or less shady, thus shovvini'

that an exposed sunn\' situation is not essential, as
might have been inferred if the Surre\- plant alone
had been found.

The genus Goimyliu belongs to the \'errucariaceae

and has representatives
in North and Central
Europe: it is now, for
the first time, included
in the flora of Great
ISritain. The accom-
jiaining photograph b\-
Mr. A. W. Dennis shows
the chief characters of
this plant, viz. : the
thin thallus, exhibiting
all the roughness of
the ground, and the
numerous g 1 o bo s e ,
shining, black fruits,
pcrithccia. with a de-
pression at the toj) of
each. Microscopic ex-
amination is necessary
to make out other
miportant characters of
this species. The size
and shape of the spores
must be known for the
[)urposes of exact deter-
mination. The fertile
period is apparent!}- at
Its best during the earh-
months of the \ear.

Interesting questions
arise respecting the
present distribution of
this plant, such as : How
wide a range has it in
the southern counties ?
Does it extend farther
north than Essex 'f It
should be looked for on
sandy banks and mounds,
both in sunn\' and more
or less shad\- spots.
Ejiping Forest would
a[)pear to most lichenists
as a very unlikeh- locality
for a new plant.

The diagnosis of
Goni^y/ia viridis appeared for the first time in the
Joiinuil of Botany, \'olume 49, Februar\-, 1911,
and it was discovered just in time to be included in
the second volume of the Monograph of British
Lichens which has been prepared by Miss A.
Lorrain Smith, F.L.S., and printed, 1911, b\- order
of the Trustees of the British Museum.

h' A.

1. Goii^ylia lurulis A.L.Sm.

M.'iynitieLi lwi_-iil\ -l!\e tiilits.

//'. Pciiuis.

184

NOTES.

ASTRONOMY.

By A. C. D. Crommelin, D.Sc.

THE CiKO-COMPASS. — This instrument was described
at the recent meetings of both the Royal Astronomical Society
and the British Astronomical Association. It may claim a
distinct astronomical interest from the close relationship that
has always existed between Astronomy and Navigation, and
also because it points to the astronomical instead of the
magnetic north, its driving force being entirely non-magnetic,
and arising from the earth's rotation. The benefit from the
navigational point of view is fairly obvious, for not only is the
magnetic deviation different for every point, but even at the
same point it undergoes a slow secular change, so that the values
marked on the charts need to be continually revised ; there is
the further obviation of all magnetic difficulties arising from
the iron in the ship. This trouble had been partially corrected
bv Airy by the use of compensation magnets, but there was
still a residual effect due to the change in the ship's magnetism
when she changed her course, and so on. The driving force in the
new compass is sufficiently powerful to enable a gearing-up
arrangement to be used, an inner card giving angular deviations
thirty-six times those of the outer one, or an entire revolution for
10', so that a change of course of a small fraction of a degree is
rendered manifest ; further, the readings of a single compass
(which in the case of warships can be placed in a secure
position below the water-line) can be electrically reproduced
on dials in various parts of the ship. There is a very ingenious
arrangement for damping the oscillations from true north by the
changing effect of an air jet escaping from the box containing the
gyroscope. A diagram was shown in which t'ne compass was
pointing some 50° from north w-hen the gyroscope was started.
It only took a few minutes to find the meridian within a few
degrees ; swings continually diminishing in amplitude took place
till after four hours they became insensible. The gyroscope
should be started a few hours before the commencement of a
vovage. It is turned by an electromotor ; hence a current of
electricity is required, but this is now available on all large
ships.

It is of interest to compare this instrument with that devised
bv Foucault to demonstrate the earth's rotation. This was in
addition to his well-known pendulum experiment, which was
repeated at the Pantheon a few years ago. His gyroscope had
freedom in all three axes, and thus, as Proctor pointed out in
"Old and New .Astronomy" page 236, it behaved "like an
independent planetary body with its own proper polar axis
directed constantly to the same point of the celestial sphere."
The gyro-compass has not so much freedom, being suspended
pendulum-wise by means of a float in a mercury trough. The
idea of giving it complete freedom was considered, but
abandoned, as it was found to be almost impossible to obtain
such perfect balance about each axis that it could be depended
upon to keep its direction in space for any length of time.
Foucault's principle was practically used by Professor Piazzi
Smyth on his voyage to Tenerift'e, described in " Teneriffe, an
Astronomer's Experiment." .A telescope was mounted on
board ship attached to a Foucault gyroscope, and it was found
that celestial objects were kept for some time in the field, in
spite of the rotation of the earth and the rolling of the ship.
Unfortunately the flywheel was unequal to the strain, and gave
way before long, but sufficient was done to illustrate the
principle.

THE APPLICATION OF PHOTOGRAPHY TO
FUNDAMENTAL ASTRONOMY.— Since the introduction
of astronomical photography, many minds have been at work
in the endeavour to apply the new' method to astronomy of
position. Of course the difficulty is that either the plates
cover only a very small region of the sky, or they are of
too small a scale to give accurate positions. Hitherto most
of the methods suggested to give results over more extended

regions have made use of the existing Tr -..Uiit-Circle, simply
substituting photography for visual work at some of the
stages. Professor Turner proposed some new methods in
a paper read before the Royal .\stronomical Society in March,
which gave rise to an interesting discussion. His proposals do
not aim at the independent formation of an entirely new
catalogue of stars, but ( II to obtain dift'erential places of further
faint stars with the aid of the existing places of the brighter
stars in the same zone, and 12) to detect systematic errors
in the existing catalogues, such as the large error of a periodic
kind that formerly affected the Greenwich clock stars, and
which ajiparently has not even now been wholly removed.
For the first problem he suggests the use of a coelostat reflect-
ing a region of the sky into a fixed horizontal telescope,
.^t the same time a small beam of light from a fixed source is
made to fall on the coelostat and thence on the plate. This
beam can be occulted by the clock pendulum at each
swing, and thus serves as a time record. An exposure is
gi\en sufficient to record stars dow-n to the tenth magnitude or
so. After ten minutes (say) the coelostat is moved back to the
first position and the process repeated. This can be done as
often as desired till there are pictures of (say) twenty regions
on the plate, all of the same declination, and differing in
Right .A.scension by known amounts. There will in the end
be enough known stars on the plate to obtain good dift'erential
positions of all the stars on it. And it is claimed that the
labour and expense would be far smaller than if all were
observed with the transit-circle.

For the second problem he suggests the use of two horizontal
telescopes at right angles, both facing a fixed mirror. Two
fiducial marks in the two telescopes, exactly 90" apart, are
found by simultaneous observations of the marks and their
reflections in the successive faces of a silvered cube, in the
place subsequently occupied by the mirror. Simultaneous
photographs of two regions in the sky 90' apart are then taken,
the following being done by moving the plates, not the mirror.
The correction for refraction is discussed, and shown to be
nearl}' constant if the altitude of the two regions is the same.
It is pointed out that for observatories in high latitudes the
most suitable study would be the observation of regions of the
same declination, 90 apart in Right Ascension, while for
equatorial ones, stars near the equator and poles might
usefully be compared, thus checking our system of fundamental
declinations.

Professor Turner has obtained a Government grant for
prosecuting experiments of the kind here briefly indicated, and
the results will be awaited with interest.

MARS. — Professor Lowell writes to me pointing out that he
had previously used the method of shift due to motion in the
line of sight, in the endeavour to separate the lines of Martian
and terrestrial water-vapour in the spectrum of Mars ividc
" Knowledge" for February). Like Professor Campbell, he
did not succeed in getting definite results from the method, and
found the comparison of the Martian spectrum with that of
the moon more suitable.

A series of glass positives of this planet, taken by Professor
Barnard with the great Yerkes Refractor, were exhibited at the
R.A.S.. and are reproduced (necessarily with some loss of
detail.) in the Monthly Notices for March. These photographs
are on a larger scale than those taken at Flagstaff, and are, I
think, superior to these in the dehneation of the dusky regions
(the so-called Seas) of which the outlines are very sharply
shown, also the various depths of shading in different parts.
They do not, however, show as many canaliform markings as
the Flagstaft" ones, though a few are indubitably shown. The
extreme narrowness of these markings makes them very
liable to be affected by bad definition, and that at Yerkes is
said to be inferior to that at Flagstaff, which was carefully
selected for this very purpose, and is at an altitude of seven
thousand feet, surrounded by a desert.

185

18f)

KNOWLEDGE.

May, 1911.

BOTANY.

By Professor 1'. Cavers. D.Sc. F.L.S.

".SOIL WAX" .AND SOIL FKRTILITV.— In the first
of a series of papers entitled " Contributions to our Knowledge
of Soil Fertility" (Proc. Linn. Soc, A'. S. Wales. 1910).
Grei.s;- Smith gives an interesting account of observations on
the action of wax-solvents and the presence of thermolabile
bacterioto.xins in soil. Water extracts from soil a substance
which is toxic to bacteria, the toxicity of the extract being made
evident by the retardation of growth, or even the destruction
of the bacteria. The toxin is destroyed by heat, by sunlight,
and by storage ; it slowly disappears from air-dried soil, and
rapidly decays in aqueous solution ; it is not destroyed by
salts such as sodium chloride or potassium sulphate. Soils
vary in the amount of toxin they contain, good soils containing
less, poor soils more. The particles of soil are covered or
" waterproofed " by soil-wax, or " agricere," and various wax
solvents such as volatile disinfectants increase the fertility of
the soil by removing this " waterproofing," when the nutrient
substances in the soil are more easily dissolved by soil-water
and attacked by bacteria.

From the results of Greig-Smith's worl<, it is clear that the
problems of soil fertility are very far from being solved yet.
Doubtless further research will throw light upon such questions
as the origin of the toxins and of the soil-wax. whether or not
the protozoa occnrrin.g in soils have any real importance in
soil fertility, and so on.

GK.AFT HYBRIDS AND C H I M A FKAS.— Some
remarkable discoveries have been made during the last few-
years as the result of research on "graft hybrids" and
allied forms.

Until 1907, only three so-called graft hybrids were known.
The most familiar is Adam's Laburnum iLabuniuni Adaiiii).
obtained in 1825 by M. Adam, a F'rench horticulturist. Adam
grafted Cytisiis piirpnrcus. a small tufted species, on the
connnon Laburnum, and obtained a shoot with intermediate
characters, which was readilj' propagated by grafting and
by cuttings, and has long been in cultivation. .A second
remarkable form is " Crataegomespilus," supposed to be a
graft hybrid between the hawthorn Crataegus nioiiogyna a.nd
the medlar Mespihis gennaiiica : the original tree is said to
exist still in Lorraine. The third case is that of the Bizzaria
orange, believed to have arisen through the inter-grafting of
Citrus Atirantium and Citrus inedica.

In 1907. Winkler (Be;-. deutscU. hot. Gcs., Band 25)
grafted a scion of Solanuiu uigrKiii (the common weed,
black nightshade) on S. Lycvpersicuiii (tomato), and after
growth was resumed, a transverse cut was made across both
stock and scion, in the hope that adventitious shoots would
grow from the cut surface along the line of contact of stock
and scion. Such shoots did actually appear, and in one case
the new shoot involved tissues of both stock and scion,
but this was clearly not a graft hybrid — one side of the
shoot was Solauutu nigruiii and the other was Solanuni
Lycopersicuni .' To this peculiar structure, Winkler gave
the name "Chimaera"; so sharply marked was the line
between nightshade and tomato that some leaves were partly
of one species and partly of the other.

In 1908 (Ibid., Band 26) Winkler obtained an apparently
true graft hybrid, which he named Solauutu tuhingcnse.
Out of about two hundred and seventy grafts between
tomato and nightshade, there arose over three thousand
shoots, among which there were five chimaeras and the
supposed graft hybrid Solanuni tubingense ; the latter,
while intermediate in character, is rather closer to the
nightshade than to the tomato.

In 1909 Winkler iZcitschr. fiir Bot.), obtained several
further " graft hybrids " by using the same methods. To
the four varieties of these forms he gave the names Solanuni
DarK'inianuni, S. Gaertnerianuni, S. proteus, and .S.
Koelreutcrianuni ; the first two resemble the nightshade

more than the tomato, the last two arc closer to the tomato.
Some of the new forms appeared as branches from chimaeras;
some of them arose several times in the cultures. In a more
recent paper iZeitschr. fiir Bot. 1910), Winkler has reported
the results of a study of the progeny of these new forms, with
some interesting details. The vegetable shoots seem able to
fuse and merge readily in \arious ways, yet the tomato and
nightshade cannot be hybridised sexually. The " graft
hybrids " without exception revert to the nearer parent, the
seedlings of ,S. tubingense, S. Dam-inianuni. and S.
Gaertnerianuni being always S. nigrum, while the seedlings
of S. proteus and S. Koclreuterianuni always are S.
Lycopersicuni. The new forms may be hybridised sexually
with the nearest parent form, the progeny being pure night-
shade or tomato as the case may be. Moreover, reversion in
the vegetative shoots is always to the nearer parent form. It
is to be noted that the behaviour of the new Solanuni forms
is exactly like that oi Laburnum Adanii. which often shows
vegetative reversion to one of the parent forms, and whose
seeds give rise not to L. Adanii but to L. vulgare.

Before proceeding to consider the interpretations of these
very remarkable results, we may briefly summarise some still
more extraordinary discoveries made by Erwin Baur, In
Baur's first paper iZeit. Abstr. Vercrbuiigslehre. Band 1,
1909) he described the minute structure of geraniums with
white-edged leaves (gardeners' " albo-marginate varieties"),
and found that the green cells and the colourless cells are
each descended from others of their kind, the external
portions (comprising two or three rows of cells) being colour-
less and the internal portions green, and the limits between
them very sharp. Since the sexual cells are derived from the
external white layers, the seedlings give pure white forms.
White branches give only white forms vegetatively, and green
branches green forms only. If a pure white and a pure green
be hybridised sexually, there arise green-white mosaic forms
in addition to pure white and pure green forms. If in the
miisaic forms the growing-point is situated on the line between
the white and green portions, there results a chimaera. such
as Winkler obtained so often in Solaiiiiiii. In a cross section
of the stem the two components appear as sectors, hence Baur
calls such forms sectorial chimaeras. For the condition
found in an ordinary Pelargonium with white-edged leaves,
Baur proposed the term periclinal chimaera. one of the
components investing the other ; the growin.g-point is peri-
clinally divided into white and green cells, the white being
outermost, so that the entire plant consists of a body of green
geranium invested by a mantle, two or three cells deep, of
white geranium !

In a recent paper, Baur (Bio/. Ccntralbl., Band JO, 1910)
notes his discovery that " Crataegomespilus " is a periclinal
chimaera, consisting of a Crataegus body with a Mespihis
investing layer either one cell in thickness (epidermis) or two
cells deep. Baur solves the riddle of Laburnum .Adanii,
finding that it also is a periclinal chimaera, with an epidermis
of Cytisiis purpureiis covering a body of Laburnum
vulgare : seedlings, are always the latter, simply because the
hypodermal layer, which produces the sexual cells, is of that
species ! When the outer layer consists of two or more
layers of cells, the seedlings are of the peripheral species,
as in Pelargonium.

Baur's astonishing discovery was almost anticipated in
1S95, by Macfarlane (7";-<7/(s. Royal Soc. Ediiibiirgli. \'ol. J7),
who made a careful anatomical study of Laburnum .Adami
and in his figures showed clearly that this form agrees with
Cytisiis purpureiis as to its epidermis and with Laburnum
vulgare as to its internal tissues, Macfarlane, however, did
not appreciate the meaning and importance of his own
observations. In one of his latest papers, Winkler has
re-investigated his Solanuni forms in the light of Baur's
epoch-making work, and finds that for the greater part they
are, as Baur had suggested, periclinal chimaeras. Winkler
supposes that what have been taken to be graft hybrids may
be actual graft hybrids, resulting from fusion of the cells of
different species ; or they may have a hybrid nature owing to
the migration between stock and scion of various substances

^fAv, 1911.

KNOWLEDGE.

1S7

as atropin or nicotin in Solanaceae ; or again they may be
chimaeras — sectorial, periclinal, or some other Icind. Carefnl
study shows that Solan u in tul)in}>ciisc, S. protetis, S,
KoelrcutcriaiiHDi. and S. Gacrtncrianitm are pericUnal
chimaeras. Of these forms, S. tiihiiigctise has a nightshade
bod}' and a tomato epidermis; S. Koclreiiteriaiiiim has the
reverse relation of the two components ; S. protcus has a
tomato periphery of two layers of cells, while S. Gacrtiieritm tini
apparently has the reverse relation. Winkler thinks, however,
that in S. Daruiiiiaiiiim he has a true graft hybrid produced
by fusion of the vegetative cells of the nightshade and tomato.
If this proves to be correct, it will be the first experimentally
produced graft hybrid, and the only instance of such a form
so far obtained.

The wonderful discoveries of Winkler and Baur, which do
not appear as yet to have attracted attention in this country,
break new ground and open up a new field of experimental
biology. To both writers belongs equally the credit due to
the pioneer in a new branch of investigation. The bearing of
these discoveries upon theories of inheritance, and in particular
upon the function of the nucleus in heredity, brings us to the
cytological aspect of graft hybrids and chimaeras. In 1905
and 1907, Strasburger {Jahrb. fiir xciss. Bot., Band 42, Band
44) investigated Laburnum Adanii from this point of view.
If this form is really a hybrid — owing its origin to fusion of
the nuclei of Laburnum vulgare and Cytisus piirpurcus —
then its nuclei should contain a number of chromosomes
equalling the sum of the numbers characteristic of the
two parent species. This is not the case, however, and
Strasburger regarded this fact as evidence against the hybrid
character of the graft. He also investigated forms obtained
by grafting tomato and nightshade, and found that there was
no migration of nuclei and no fusion of the nuclei of stock and
scion ; hence he concluded that Winkler's graft hybrids are
merely chimaeras, calling them " hyperchimaeras " — forms in
which the elements of the two parent forms are more or less
intermingled but without any real nuclear fusion. Strasburger
therefore denies emphatically the reality of graft hybrids, but
as we have seen, Baur's results are of vastly greater import-
ance than these cytological observations, and they enable us to
place upon Winkler's work an interpretation different entirely
from those made by either Winkler himself or Strasburger.

Strasburger goes on to consider the case of parasitism
between Angiosperms ; for instance, between mistletoe and its
host plants, where there is an intimate relation between the
two plants, but no mingling of nuclei. In grafting, a bud
from the point of union might possibly give rise to a shoot
bearing a flower in which an anther might be from the scion
and an ovary might be from the stock ; close fertilisation
might then give rise to a true hybrid, but, Strasburger argues,
hyperchimaeras would be more likely to produce flowers the
seeds of which would give rise to pure plants of either the
scion or the stock. The fact that pollen from his graft
hybrids would cause fertilisation in tomato or nightshade,
while neither of these plants can be crossed with the other, is
regarded by Winkler as proof of true hybrid character ; but
Strasburger thinks that the pollen was probably pure,
consequently fertilisation was to have been expected, but that
only nightshade or tomato would result.

Winkler himself, in his account of the generation obtained
from the seed of his hybrids, gives some results as to the
chromosome numbers. In tomato the A' (sexual) and 2X
(somatic) numbers are 12 and 24, while in nightshade they are
36 and 72. He suggests that the difference in chromosome
numbers may prevent the crossing of the two species, though
noting the fact that Rosenberg crossed two species of Drosera
with 10 and 20 chromosomes in the sexual nuclei and obtained
a hybrid with 30 chromosomes as the 2A' number. If the
Solan uni hybrids are due to fusion of somatic nuclei, they
should have 72 + 24, or 96 chromosomes, unless the fusion
should be followed by reduction, in which case the number
would be 48. Winkler found the A' number to be 36 in
S. tubingcnse. S. Darwinianum. and S. Gaertncrianuni,
and found 12 in S. protcus and S. Koclrcutcrianum. the

first three of these reverting in their pollen formation to night-
shade and the other two reverting to romato. Winkler suggests
that the graft hybrids more closely resembling nightshade are
from nightshade cells, and that those resembling tomato are
from cells of that parent, the nuclei being like those of one
parent or the other, but the protoplasm being mingled with
that of neighbouring cells. This theory, implying that the
protoplasm has great influence, obviously interferes with the
now generally accepted view that the nucleus is the sole
bearer of hereditary characters — but, as already stated, Baur's
results probably make both Winkler's and Strasburger's
explanations unnecessary.

Much further work is required both on the experimental
production of graft hybrids and chimaeras, and the histological
and cytological characters of these forms. In his most recent
account of the cytology of the Solanum forms, Winkler (BtT.
dcutsch. bot. Gcs., 1910) states that S. tubingensc. S.
protcus. S. Koelrcuterianuni. and S. Gaertncrianuni are
periclinal hybrids; but that S. Darwinianum, at least in the
subepidermal layer of the stem apex, is a fusion hybrid. The
germ cells of S. Darwinianum have 48 chromosomes, and
since the parents (tomato and nightshade) have 12 and 36
chromosomes as the A numbers, \\'inkler infers that the
subepidermal layer from which the pollen is derived must
have 4S chromosomes ; he supposes that a nightshade cell
with 24 chromosomes has fused with a tomato cell with 72,
gi\ing a nucleus with 96. and that in the progeny of this
nucleus the number is reduced by halving.

CHEMISTRY.

By C. AiNSWORTH Mitchell, B.A. (Oxon.l, F.I.C.

SPONTANEOUS COMBUSTION OF COAL. — The
various factors that tend to bring about the spontaneous
combustion of coal have been made the subject of an
experimental investigation by Messrs. Parr and Kressman,
who have published their results in the Journ. hid. Eng.
Chcm., 1911, III, 151. They show that oxidation processes
begin as soon as the coal is taken from the mine, and that
when the temperature produced by external factors reaches
a certain point, autoxidation sets in and results in the
ultimate destruction of the coal. The average temperature
for autoxidation lies between 200° and 275° C, according to
the state of division of the coal, while ignition takes place at
about 350' C.

The factors contributing to raise the temperature of the
coal to the stage of autoxidation include : — (a) External
sources of heat, such as sunlight, or impact due to the
method of unloading; (b) Fineness of division; (c) Readily
oxidisable compounds of a bituminous nature; id) Iron pyrites,
the presence of as little of which as five per cent, may raise
the temperature by about 70' C. ; (e) Moisture, which
promotes the oxidation of the pyrites ; (/) Oxidation of carbon
and hydrogen, which takes place at temperatures above 120° to
140' C. ; (g) The fourth or autogenous stage of oxidation.

Any measures to prevent spontaneous combustion must be
based upon a consideration of these facts. -All external
sources of heat must be eliminated as far as possible, and all
dust or finely divided material separated. Complete dryness
in storage will pre\-ent oxidation of iron pyrites, which is a
fruitful source of danger in coal from the mid-American fields.
No system of sorting at the mine can eliminate all risk from
this source. Drenching the coal with water may increase the
chances of oxidation where the sulphur is distributed through-
out the whole mass, while complete submersion of the coal
will probably not prove practicable. Preliminary heating
might be used to bring about the initial stages of oxidation,
and thus eliminate some of the factors which would
subsequently supply the necessary heat for destructive
oxidation processes. Treatment with chemical agents does
not hold out much chance of success, but a system of circulat-
ing a cooling li(]uid through pipes distributed throughout the

ISS

KNOWLEDGE.

May. 1911.

mass appears more promising. On the other hand, the forma-
tion of air passages, which is frequently advocated as a
remedy, seems likely to do as much harm as good, since the
heat of the oxidation promoted by the access of fresh oxygen
may more than counter-balance the heat carried away by
the air currents.

THE BL.\CK GLAZING ON GRECIAN POTTERY.
— Many of the specimens of early Greek and Italian pottery
have been coated with a fine black glazing upon a terra cotta
ground, but the means employed to obtain this has long been
a lost secret. According to M. A. Verneuil, who has recently
published the results of his experiments upon the subject
iConipffs Rcndtis. 1911. CLII. 380), the pottery has
apparently been fired in an oxidising furnace : but the only
way in which he was able to produce a similar black enamel,
was by heating a flux containing magnetic oxide of iron in a
reducing furnace. A mixture of iron filings, sodium carbonate
and the powdered calcareous clay of the pottery itself yielded
a flux, which when heated in an oxidising furnace produced a
black glaze, which resembled the ancient black lustre in
showing a greenish sheen in reflected light, but was not equal
to it in depth of tone.

INFLrEXCH OF CIlKdMUM COMPOUNDS ON
PL.4NTS. — .-Xn account of the experiments of Dr. P. Koenig,
upon the influence of certain chromium salts upon plant life is
given in the Clieiii. Zcntralblatt (1911. I, 498). From these
it appears that when applied in very small quantities chromium
compounds, and especially ehronious acetate, have a stimulat-
ing influence upon the germination and growth of plants, but
that in large quantities their action is very toxic, and has a
particularly injurious effect upon the roots. Solutions of
chromates are the most poisonous, but their action may be
minimised by adding an equivalent amount of lime to the
liquid, or by the addition of salts of metals, such as silver or
lead, which form insoluble chromates. In the case of plants,
such as lupins, however, to which lime is injurious, the
presence of the chromium intensifies the effect of the lime.

The degree of toxic action also varies with the composition
of the plant, and the nature of the soil. Thus plants which
contain much silica oft'er the greatest resistance to the action
of chromates. while vegetation in a sandy soil is much more
affected than that growing in loam, probably on account of the
greater proportion in the latter of substances capable of
combining with the chromate.

The amount of chromium taken up by the plant differs in
the case of different compounds, and it is remarkable that
alkali bichromates, which are the most toxic of the chromates,
give up least chromium to plants. There is also a greater
accumulation of chromium in the roots than in the other parts
of the plant.

As the results of these experiments would indicate, a
solution of potassium bichromate has proved very effective as
a weed killer.

C'.HoLouV.

By Russell V. GwiwEr.L, B.Sc, .V.R.C.S., F.G.S.

CLIMATE AND PHYSICAL CONDITIONS IN PRE-
CAMBRIAN TIMES. — In the January — February number
of the Journal of Geology, the oldest known rocks in
Canada .are dealt with by A. P. Coleman. Constituting
the Keewatin Series in the west and the Grenville and
Hastings Series in the east these pre-Huronian rocks
stretch for one thousand miles across the country. The
Huronian or Algonkian rocks, both sedimentary and
eruptive, are already admitted to have been formed like rocks
of later times. We find evidence in these early times of
climates not unlike those of later ages, when wind and
weather, flowing rivers, and beating waves and even great ice
sheets did their regular work. In northern Ontario glaciers

formed boulder-clay in latitude 46" showing no hint of the
action of primeval heat such as the usually accepted \ersion
of the Nebular Hypothesis demands.

But there is much less certaint\' regarding pre-Huronian
times. The world was already very old before the Huronian
ice-sheets began their work. Many geologists have been
inclined to see in the underlying " basal complex " portions of
the earth's original crust, of plutonic rocks and crystalline
schists consolidated from the cooling globe, which was still
too hot to permit the condensation of water, so that no rivers
or oceans were possible. The conviction, however, is growing
in the minds of many geologists that, although the Huronian
basal conglomerate means a break in time, it does not mean
a break in the continuity of marine and terrestrial processes,
but that the affairs of the world were conducted in the same
way before this great inter\al as after it.

The author then shows that these pre-Huronian rocks
include large amounts of sedimentary materials — limestones,
dolomites, slates, gneisses having the composition of clayey
sandstones, and so on. In the east the seas were clearer and
deeper and limestones predominated, while in the west volcanic
activity was very pronounced producing thousands of feet of
ashes. and so on. There must have been great land-surfaces from
which rivers flowed bringing down sand and clay. The sea
contained plants to furnish the carbon (often reaching several
per cent, in slates, gneisses and limestones! while the lime-
stones hint at calcareous algae or animals having hard parts.

Similar sediments penetrated by granites and gneisses
occur in the Lewisian of Scotland and in the Ladogian of
Finland, and so on.

It is thus evident that the Keewatin and Grenville Series
of .America, like the oldest rocks of Europe, do not take us
back to the commencement of geological time, since they
include clastic sediments which imply the weathering and
erosion nf previous rocks before they were spread out on the
sea bottom. "We have extended our outlook much farther
into the past, but there is still an impenetrable background
beyond. V\'e shall perhaps never be able to say ' m the
beginning ' ; but we may safely say that there is no hint of a
molten earth in process of cooling down. If the earth was
ever hot it had so far cooled down before the oldest known
rocks were formed as to allow air and water and life to do
their work in the world very much as they do now. If the
earth ever passed through a period of great heat it was at
a time too remote in the past to leave a geological record or to
have any special interest for the geologist."

THE GEOLOGISTS' ASSOCIATION.— The Geologists'
.Association celebrated the fiftieth anniversary of its founda-
tion by the publication of a useful work entitled " Geology in
the Field : the Jubilee Volume of the Geologists' .Association."
This book, edited by Messrs. Monckton and Herries, has
within the last few months been completed by the issue of
Part \'.

The places visited during the fifty years' existence of the
Association were arranged in groups or districts, and a number
of geologists, selected for their special knowledge of the
localities, were asked to contribute descriptive articles on the
respective districts, using the previously issued reports of the
excursions as a basis. The scope of the work is confined,
however, to England and Wales.

Hardly is this book completed before the work of the
Geologists' Association comes once more before the general
public. For, on behalf of the Association, Dr. J. W. Evans
is arranging a series of exhibits in the Science Section of the
Coronation Exhibition at Shepherd's Bush. These exhibits,
intended to illustrate the work of the Geologists' Association,
consist of maps and relief-models of districts visited and
geological specimens collected by members from these districts.
By the time these notes are published, the exhibition will
probably be open,

A NEW INDUSTRY IN THE HEBRIDES,— The finding
of iron ore in Raasay, one of the islands of the Inner Hebrides

May. IQll.

KNOWLEDGE.

189

lying in The Minch. between Skye and the Torridon district of
the Ross-shire mainland, was announced late in the past year.
The discovery was really made eighteen years ago by Mr.
H. B. Woodward, F.K.S., in the course of his work on the
Geological Survey, but the deposit has been recently
investigated from a commercial point of view, and as a result
the great firm of ironmasters and colliery owners, Messrs.
^\'m. Baird & Co., Ltd.. of the Glasgow Coalfield, have bought
the island. The deposit is situated at the junction of the
Upper and Middle Lias, thus corresponding approximately
with the position of the Cleveland ironstone. It is a
ferruginous limestone forming a good basic ore. The deposit
is from six to seventeen feet in thickness and probably many
millions of tons will be available. Though it is not likely
that blast furnaces will be erected on the island, for the ore
will merely be calcined and then shipped to the South, still
the opening up of mining operations in this quiet and remote
spot will greatly alter the character of this district of grouse
moor and deer forest.

This will not, however, be the only mineral industry carried
on in that part of the Western Isles, for at two places on the
adjacent coast of Skye, quarrying has been in operation on a
comparatively small scale. The deposits of diatomite. a lake
deposit consisting of the siliceous tests of minute plants, have
been worked for many years in a wild, desert region north of
Portree, and the calcined product shipped away for use in a
multitude of industries — the manufacture of fireproof partitions,
ot tooth powder, of dynamite, of disinfectants, and so on. A
beautiful white marble, somewhat like the Carrara stone, and
produced by the metamorphic action of granite on Cambrian
limestone, has been ijuarried intermittently near Broadford, and
within the last four or five years systematic operations have
been carried on, a mineral railway is now being constructed,
and an export trade is being opened up.

THE P.ASS.AGE OF LIGHT THROUGH CRVST.ALS.
— The issue of Dr. Tutton's popular account of the fascinating
phenomena of crystallography ("'Crystals." International
Scientific Series, 1911), recalls his evening discourses before
the British .Association in Winnipeg, and the Royal Institution
in London.

I had the good fortune to be present at the Royal Institu-
tion lecture, and shall never forget the wonderful experiments
then performed. The most "showy" demonstration was an
illustration of the fact that the light reaching the eye from a
crystal is of two kinds, namely, white light reflected from
the exterior faces and coloured light which has penetrated the
crystal substance and emei'ges refracted and dispersed as
spectra. Two powerful beams of light from a pair of widely
separated electric lanterns were concentrated on a cluster
of magnificent large diamonds arranged in the shape of a
crown. The effect was not only to produce a bla^e of colour
about the diamonds themselves, but also to project upon the
ceiling of the lecture theatre numerous images in white light
of the poles of the electric arc, derived by reflection,
interspersed with coloured spectra derived from the rays
which had penetrated the diamonds and had suffered refrac-
tion and internal reflection.

The " Mitscherlich experiment." with gypsum, was also per-
formed by Dr. Tutton. In this, a suitably-cut section of the
mineral is shown with convergent polarised light, the resulting
interference figure being projected on to a screen. .\t the
ordinary temperature, the mineral is biaxial with a wide optic
axial angle. .As the crystal is heated gently this angle
decreases, then closes up altogether (so that the mineral
becomes uniaxial) and finally opens out again in a plane at
right angles to the original optic axial plane. On allowing the
crystal section to cool again the phenomena are repeated in
the reverse order. No other mineral exhibits this phenomenon
of crossed-axial-plane dispersion, by change of temperature
alone, quite so well as gypsum. When one appreciated the
significance of the interference figure as projected on the
lecture-screen, admiration was called forth as there appeared
first the usual lemniscates and rings around the two optic axes

at the right and left margins of the field; then the axes
approached one another and united ia the centre of the field,
the dark hyperbolic brushes combining to produce a
rectangular cross, and the rings and i'liiniscates becoming
circles: then the dark cross opened era .jsr.in into brushes,
but in the vertical direction, and the circl. s elongated out into
ellipses and lemniscates again. Dr. Tutton's book deals with
many other interesting crystallographic topics, such as the
significance of isomorphism and dimorphisiu, the phenomena
of " right- and left-handedness " in crystals, those peculiar
optically-active liquids described as " li(|uid-crystais " and so
on.

METEOROLOGY.

By John A. Curtis, F.R.Mf.t.Soc.

The weather of the week ended March 18th, as epitomised
in the Weekly Weather Report issued by the Meteorological
Office, was generally cold, wet and dull, with snow at many
stations. Temperature was below the average in all districts.

Readings above 50' were reported only at Tottenham,
.Armagh, Killarney, and in the English Channel, the highest
being 54 at Killarney and at Guernsey. The lowest miuinuuu
was 22 at Llangammarch Wells on the 1 7th, but readings below
freezing-point were observed in all districts. The minimum
on the grass was as low as 11" at Llangammarch Wells, and 18"
at Plymouth. Rainfall was in excess, except in the North and
West of Scotland, England N.W., and in Ireland; in some
places the amounts collected were from three to four times as
great as usual. The highest total reported was 1-93 inches ;it
Hillington. Norfolk. Sunshine was in excess in Scotland and
Ireland, but was generally in defect elsewhere. The sunniest
station was Castlebay. Harra Island, with 51-9 hours (65%),
while Deerness, still further to the North, but to the East, had
only Z-i hours (3%), Glasgow reported 28-7 hours (36%),
while Eastbourne had only 17-9 hours (22%). The total
duration of sunshine at Westminster was 9-1 hours (11%).
The temperature of the sea-water varied from 48° at Seafield,
to 37° at Cromarty. .A thunderstorm was reported at
Rothamsted and Raunds on the 13th: at the latter station it
was accompanied by a violent snowstorm and great darkness.

The week ended March 25th was cool and unsettled, with
snow in many places, and with thunderstorms in the S.E. and
S. Temperature was above the average in England S.E. and
in the English Channel, but was below the average elsewhere.
The highest readings recorded were 63" at Tottenham on
the 22nd, and 62° at Margate and at Guernsey. The lowest
of the minima were 22^ at Fort .Augustus and at Balmoral.
On the grass the minimum fell to 18^ at Balmoral and to 19°
at Llanganunarch Wells. Rainfall was light as a rule, and in
Scotland W. and Ireland N. the week was rainless. In
Scotland N. the total district value was only 0-03 inch, or 1-00
inch below the average for the week ; in England N.W. the
amount was 0-04 inch, or 0-49 inch less than usual. Bright
sunshine varied much in different localities, but was generally
below the normal. Castlebay was again the sunniest station,
with 54- 7 hours (65%), Worthing coming next with 50-9 hours
(61%). Sheffield had only 9-0 hours (11%): Westminster
reported 19-9 hours (24%). The mean temperature of the sea
ranged from 37-5 at Cromarty to 47" -0 at Newquay.

The week ended April 1st. was dry, though cool and cloudy,
but heavy rain commenced in the S.E. of England late on
Saturday. Temperature was in excess in Scotland N. and
England N.W., but was in defect in all other districts.
The highest maximum reported was 63° at Arlington, N.
De\on, on the the 30th, but in most of the districts the
thermometer did not rise as high as 60°, and in England N.E.
the maximum was only 51°, and at individual stations it was as
low as 45". The lowest readings for the week were 22" at
Balmoral, and at Markree Castle, and 23° at Cromer. The
minimum on the grass was 15° at Markree Castle.

Rainfall was below the average everywhere except in England

190

KNOWLEDGE.

May, 1911.

S.E., and the English Channel. \t several of the stations the
week was rainless. The amounts collected were as a rule
small, but at Tunbridge Wells 1 • 22 inches was collected in three
days. Sunshine was greatly in defect, except in Scotland N.,
and in England N.W., where it was slightly in excess. In
England E. the district value was 12 hours (14%) as com-
pared with an a\erage of 34 hours (39%). The sunniest
stations were Stornoway and Douglas, each with 39 • 6 hours
(45%), while Guernsey reported 17-2 hours (20%), and
Eastbourne only 11-7 hours (13%). At Westminster the
total duration was 10-8 hours (12%). The mean temperature
of the sea-water ranged from 38° -6 at Cromarty to 47° -4
at Newquay.

The weel< ended April 8th was very cold indeed, with but
little sunshine. Much snow was experienced in the southern
and eastern parts of England. Temperature was below the
average everywhere. In England S.E.the mean was 36" -9, or
8° -3 below the normal, a lower mean temperature than had
been recorded in this district, in the corresponding week, for
thirty-four years. Only in Ireland and the English Channel
was the district mean as high as 40"'. The highest maximum
(59°) was noted at Killarney, on the 2nd, and temperatures
of 58° were also reported from Cullompton and Wick. The
lowest readings came as a rule on the 5th, on which day a
temperature of 17' was recorded at West Linton. Frost
was reported at every station except Llandudno and
Donaghadee. The lowest reading on the grass was 14°
at Armagh and Markree. The total Rainfall was below
the average in all districts except the English Channel,
where it was just above the normal. At several stations the
week was rainless, and in Scotland N, the total fall was only
.about one-twentieth of the average amount. Sunshine was
deficient except in Scotland W. and England N.W. The
sunniest stations were Valentia 54-7 hours (61%) and
Falmouth 45-7 hours (51%). Westminster reported 26-0
hours (29%) and Birmingham only 10-3 hours (ll?/o). The
temperature of the sea-water varied from 37" at Scarborough
to 50° at Scilly.

During the week ended April 15th, the weather was very
fine in most parts of these Islands, but with a good deal of
cloud in the North, Temperature was below the average
except in England N.E., and in Scotland, During the first days
of the week the maxima were very low generally, but a warm
spell set in, and towards the close of the week temperatures of
65" and 66° were recorded. The highest maximum was 68° at
Killarney on the 13th, but readings of 60° and upwards were
reported from each district except Scotland W., and the
English Channel, In the Channel Islands the maximum
did not exceed 58", and at Scilly it was only 55°, Frost
was recorded in each district except the English Channel,
and at Raunds and Llangammarch Wells the thermo-
meter fell to 23° ; at the latter station the thermometer
on the grass went down to 15°. Rainfall was in defect in all
parts, and many stations, including all those in England S.W.,
were rainless. Sunshine was below the average in Scotland
and in England N.E., but above it elsewhere. Falmouth
reported the greatest amount, 68-2 hours (73 %), and Fort
Augustus the least, 14-1 hours (15%). At Westminster the
total duration was 34-7 hours (37%). The temperature of
the sea- water varied from 39° at Cromarty to 53° at Teelin.

WEATHER INSURANCE.— An interesting application of
Meteorological Statistics for the purposes of Insurance is
announced by the Excess Insurance Co., Ltd., which offers
for a suitable premium to issue a " Pluvius Policy " under
which an agreed amount of money will be paid to any holiday-
maker, or other person, who experiences in any one week, over
a specified period, more than two days of rain, amounting in
each day to over 0-20 of an inch. The policy will in every
case specify the place, the record of rainfall at which is to
govern liability, together with an indication of the authority
keeping the record. In most cases the authority will be the
Town Clerk, or some observer recognized by the Meteoro-
logical Office, The rates are so arranged that a payment of
£l per week as premium will provide for £8 " compen-

sation " should the rainfall amounts exceed 0-20 inch on more
than two days during the week.

Policies must be taken out seven days before the period to
be covered commences.

There are other forms of policy provided for. with \arying
rates, both of premium and of amount payable, but the under-
lying principle is the same in each.

An obvious objection to the scheme is that it provides
" compensation " for loss or damage when no loss or damage
has, in fact, been sustained ; for, although a person whose
holiday is interfered with by rainy weather may have to spend
money in other and unexpected directions, and so suffer
pecuniary loss owing to the rainfall, there is nothing in the
scheme as announced to hinder anyone remaining, for instance,
in London and claiming "compensation" for rainy days in
Plymouth or Scarborough. In this way "insurance" may
conceivably degenerate into gambling and prove harmful.

MICROSCOPY.

By A. W. Sheppard, F.R.M.S.,

wit It the assistance of the fulloK'iiif> iiiicroscopists : —

Arihur C. Bankiei-d. Arthur Eari.and, F.R.M.S.

James P.urton. Richard T. Lewis, F.R.M.S.

The Rev. E. W. Bowell, M.A. Chas. F. Rolsselet, F.R.M.S,

Charles H. Caffvn. D. I. Scolrfield, F.Z..S., F.R.M.S.

C. D. Soar, F.R.SI.S.

LUMINOUS BACTERIA. — No phenomenon in nature is
so striking as the production of light by living organisms ;
considered either from the scientific or the popular point of
view it commands attention. The difiiculty experienced in
accounting for it is indicated by the fact that Darwin deals
with it under the heading of " Special Difficulties of the
Theory of Natural Selection."

Light production occurs principally among marine animals,
but in these there are special organs involved. In the case of
bacteria which are light-producing, it is difficult to suppose
that special organs exist, they being minute uni-cellular
bodies, consisting essentially of a mass of protoplasm enclosed
in a cell wall; hence the possibility of a special light-produc-
ing organ is almost excluded. Light-production in living
animals is essentially different from that of inert chemicals or
of the phosphorescence produced by electrical means.
Phosphorescent chemicals in all cases have the power of
absorbing light and of re-emitting it either of the same, or of
a somewhat greater wave-length. Bacteria emit light which
is produced entirely by themselves, altogether independently
of anv extraneous light source ; in fact, they grow and produce
light better if kept entirely in the dark. In general, light can
only be produced by raising the temperature of a suitable
substance until it becomes luminous. It therefore follows
that a great deal of the energy so converted is lost as heat ; in
fact, to such an extent is this the case that an ordinary electric
lamp, even of the highest efficiency, does not give out in the
form of light more than about five per cent, of the energy
expended in raising the temperature of the filament. Bacteria
produce light which is unaccompanied by any heat radiations,
and so far as the investigations of the writer have yet
proceeded, there is no evidence that any in\isible radiations are
produced by them at all. Their efficiency as light-producers is,
therefore, extremely high, and were it possible to carry out on
a commercial scale the process of light-production as it occurs
in bacteria a tremendous step forward would be taken.

Essentially, the process is an oxidation one, as in addition
to a nutritive material on which the bacteria may grow and
reproduce, a supply of oxygen is necessary. The natural
habitat of these organisms seems to be almost exclusively
.sea- water, or at least water such as is found in estnaries
where an appreciable quantity of saline matter is present.
They will grow and exhibit their light-producing properties on
an ordinary peptone-beefbroth gelatin medium, but they do

May, 1911.

KNOWLEDGE.

191

FiGURr

A flask photographed by the Ught
of the bacteria within.

uot all emit the greatest possible amount of light unless an
increased quantity of saUne matter is present. It was

recognized that prob-
ably in sea - water
would be found the
necessary constituents
for an artificial medium,
and after a series of
f.\periments that which
best suits them is found
to be an ordinary gelatin
one to which has been
added 2- 75 per cent, of
sodium chloride. ■ 75 per
cent, of potassium chlo-
ride, and -25 per cent,
of magnesium chloride.
It is important that
the medium should be
neutral, or very slightly
alkaline: an acid
medium is entirely un-
suitable fortheir growth.
The most easily procured organism of this group is the
Photobacterium phosphorcsccns. It may be obtained
from a dead herring or mackerel. The
fish should not be washed in fresh water
after being caught. It should be placed
in a closed receptacle, such as a large-
sized Petri dish, for about twenty-four
hours at approximately 20' C. At the
end of this period there will probably be
some spots which phosphoresce brightly.
Plate cultures may be made from these
spots, and in three to four days at
ordinary room temperature the plates,
on examination in the dark, will probably
show some luminous colonies. Sub-
cultures may be made from these, and
the organisms may be kept going in
artificial cultivations on the medium
mentioned for several weeks without
difficulty. Fish-broth or peptone-beef-
broth may be substituted for a solid
gelatin medium. It is necessary, how-
ever, if brightly luminous fluid cultures
are required, to resort to some
method of aeration, a supply of free
oxygen being essential. In any case,
when making fluid cultures, the media
should be thoroughly well shaken up to
ensure that as much oxygen as possible is
present in solution before the organisms
are inoculated into it. If the maximum amount of luminosity
is aimed at. oxvgen may be allowed to bubble slowly through
the medium directly any luminosit}' appears, and although
^— the period over which

J the light production

V occurs is thereby re-

duced, the luminosity
is extremely brilliant
while it lasts.

Figure 1 shows a
flask of these organisms
photographed by means
of their own light, which
will gi\e some idea of
the brilliancy to be
obtained under these
conditions.

Figure 2 is a
photograph of Lord
Lister, illuminated by
means of growths on
solid media. On each
side will be seen

Figure 3.

Colonies of bacteria on a Petri dish
photographed by their own light.

FlGlRE 4.

Pliotobacte rill til balticum grown

in fish-broth.

tubes containing the organisms and several of them
were placed underneath throwing the light upwards.

Figure 3 is an ^^m-^

ordinary Petri dish with
luminous colonies on it.
These again were photo-
graphed entirely by their
own light, the colonies
standing out brilliantly
on a dark back-ground.
The exposure in photo-
graphing these organ-
isms is always some-
what prolonged;
although their visual
luminosity is high yet
their photographic
action is not rapid, as
the light emitted does
not lie in that portion
of the spectrum which
is photographically
most active. There is
the further difticulty that the light happens to lie in a region
of the spectrum to which photographic plates are particu-
larly insensitive, so that due allowance
must be made for these two factors
if any attempt is made to obtain a
photograph of these organisms by their
own light.

Some twenty-five varieties of these
organisms have been described, and it
is also stated that other bacteria such
as the Cholera vibrio, are known to
produce light under certain conditions.
Of these twenty-five described species
it is more than likely that some are not
really entitled to be regarded as distinct.
A broad classification of them may be
made by separating those that grow at
low, and those that grow at a higher
temperature. There are two or three
species found in Northern latitudes that
thrive and produce light at 0°C.,
whereas there are certain other varie-
ties which grow in Southern latitudes,
particularly in the Indian Ocean, that will
go on producing light at a temperature
of from 30"C to 35"C. The writer has
had through his hands at various times
some fourteen varieties, as well as one
which there is reason to think is a new
species, originally identified at the Marine
Biological Laboratory, Plymouth. Morphologically the
organisms vary widely: the common species Photobacterium
phosphorescens already mentioned, is a short thick rod,
which when grown on
a medium containing
more than three per
cent, of saline matter
assumes a much
shorter, thicker appear-
ance, and is almost
coccoid in form. Nearly
all \arieties change ?
considerably in form
when artificially culti-
vated for long periods,
so that it is often
difficult to identify :i
particular species by
its microscopic appear-
ance. Owing also to the
amount of saline matter
necessary in the med-
ium, the organisms

Figure 2.

A picture of Lord Lister illuminated

bv bacteria.

Figure 5.

Photobacterium balticum grown
in peptone-beef- broth.

192

KNOWLEDGE.

May. 1911.

often develop vacuoles, and assume varied shapes. They
all stain easily by most of the well-known bacteriological
staining methods, and in most, if not all cases, a flagelluni
or fiagella may be demonstrated.

Figures 4 and 5 show the marked differences that occur
in some species under different methods of cultivation
(Pliotobacteriiim bttlticniuK Figure 4 is grown on a
fluid fish-broth medium. Figure 5 is grown on peptoue-
beef-broth containing the maximum amount of saline matter
that the organism will tolerate. In each case fiagella are
clearly shown.

The question whether the organism itself produces light as a
direct metabolic process, or whether it is an extra-cellular
bacterial product that is light-producing, is still an undeter-
mined point ; but all the evidence goes to show that the light
production is undoubtedly associated with the life-history of
the organism. By no experimental means has it as yet been
possible to isolate the light-producing material from the
actively-li\ing cell.

These organisms may be recommended to the amateur
microscopist as a most fascinating field of research, in which
there are still many problems to be solved ; they present no
great cultural difficulties, nor do they re(juire the resomxes of a
bacteriological laboratory in which to carry them out.

J. Edwi.v B.\rnakd. F.K.M.S.

KO\AL MICKt>SCOPIC.-\L SOCIETY.— March 15th.
1911. Mr. H. G. Plimtner, F.K.S.. president, in the chair.
Dr. Ralph Vincent gave a lantern demonstration on " Some
Photomicrographs illustrating the morphology of the organisms
concerned in the production of acute intestinal toxaemia in
infants." These included Bacillus sKbtilis. B. iiicsciifcriciis.
'■ No.7,"B. iiiescntcriciis viilgatiis. and B.protciis vulgaris.
The photographs showed the organisujs stained, unstained and
during life. Photographs were also shown of Streptococcus
lactictts. Bacillus acidi lactici and B. huli^aricus.

Mr. F. \V. Watson Baker contributed a paper on "".\nomalies
in Objective Screw Threads."

Mr. E. M. Nelson described a new piece of apparatus con-
sisting of an objective mount fitted with an iris diaphragm, in
which the iris was just clear of the back lens, and its mo\'e-
meut was controlled by a collar adjustment. This piece of
apparatus would no doubt be of great value to workers who
employ dark -ground illumination for viewing bacteria, and so on,
as in many instances, owing to defects in the illuminator, it was
not possible to obtain a dark field when the objective had a
wide an.gle. This fault was remedied by stopping down the
aperture of the objective by means of the diaphragm. Mr.
Nelson also described some new objectives and eye-pieces
made by R. W'inkel, of Giittingen, and contributed a short
historical and descriptive resume of the "Variable Microscope."

Mr. J. Murray brought forward a Report on the Rotifers
collected by the British .-Vntarctic Expedition of 1909.
Forty-six Bdelloids were collected, bringing the AustraUan
list up to fifty-four species. There were seven new
species, and ei.ght others occurred as distinct varieties.
The new species were Plulodina australis. Callidina
arinillafa. C. lepida, C. longistyla. C. scrrulata, C.
iiiirahilis and Habrotrocha straiigulata. The most
aberrant form was C. iiiirabilis. which had peculiar
fleshy processes on the trunk. The rotifera fauna of the
Australian Alps resembled that of Britain. The arid low-
lands were very unproductive. Three-fourths of the species,
and all the new species, occurred in the Blue Mountains.
at moderate elevations. Eight species of non-Bdelloid rotifera
were also noted from the water supply and ponds in Sydnev.

THE PREVENTION OF FADING OF ANILINE
STAINED MICROSCOPIC PREPAR.ATIONS.— Incommon
with many microscopists I ha\e found that films of blood,
bacteria, and so on. when stained with almost any of the
aniline dyes, fade after a time when mounted in Canada
Balsam. This is especially the case with methylene green,
thionin, methylene blue, or methylene blue and eosin, either

separately or combined as Jenner's stain, and all the modifica-
tions of Rouuinowskv's \aluable stain, e.g.. Giemsa, Leishmann,
^^"right.

There is no doubt but that the cause of fading in balsam-
mounted preparations, judging from my own experience and
from the expression of the opinion of numerous authorities on
the subject, is acidity whether present at the time of mounting,
or developing subsequently from oxidation of the mounting
medium.

I will not enter into details of my experiments or the state-
ment of the authorities as to the facts which lead me to the
above conclusion. They have been described in full elsewhere.
Lancet. 1911, Vol. I, page 876.

It may. I think, be stated that practically all substances of
the nature of balsams, oleo-resins or cedar oil will sooner or
later oxidise and become acid and, therefore, are liable to cause
fading of the aniline stains.

It is not possible to obtain .a neutral Canada Balsam that
will remain neutral.

.■\fter numerous trials. I have found that I'araftinuin
liquiduin is a neutral medium w^hich does not undergo
oxidation and. therefore, does not become acid.

I have used a pure form of liquid paraffin, namely
Burroughs and W'ellcome's " Parolein " and so far have found
the results admirable. It is more trouble to mount in than a
balsam, and the preparations require to be ringed or
cemented round with some cement which is also neutral.
The following is the method I use for mounting films of blood
or bacteria which are spread and stained on the slide.

.•\ perfectly cleaned cover-glass is held in a pair of forceps
over the flame of a spirit lamp for a second or two to drive off
any moisture on the glass, and is then laid on a clean sheet of
notepaper. .A very small drop of Parolein is placed on the
centre of the cover-glass, and the slide with the blood film,
after being shghtly wanned over the flame, just enough to be
sure that the glass is perfectly free from moisture, is gently
let down on to the cover-glass. In a second the oil has run
nearly to the margins by capillarity, and a little pressure on
the cover-glass will send it completely to the margins. If the
amount of oil is just sufficient to reach the margin of the
cover-glass so much the better. If there is too much oil,
the preparation is placed under a piece of blotting
paper and the excess of oil pressed out as much as possible.
One soon learns how much oil is required to make a clean
preparation. .A not uncommon thing is to find that the cover-
glass rocks, that the oil has only covered about three parts of
the square or circle. This is almost always due to the presence
of a minute particle of dust between the cover-glass .and slide,
and is to be prevented by seeing that the co\er-glass is quite
clean and free from dust before placing the oil on it, and by
just dusting gently the film surface on the shde. But usually
it is easily remedied by running in a \ery small drop of
Parolein at the margin of the coverglass.

To fix the cover-glass in position it is necessary to ring it
round with some cement. The cement must be neutral or
there will be fading, and the cement must withstand the action
of the immersion cedar oil. I first ring round the preparation
with .-Vpathy's Cium Syrup made as follows: Picked gum
arable, cane sugar not candied, distilled water, of each, 50
grammes. Dissolve over a water bath and add 0-05 grammes
of thymol. I test the reaction with litmus paper, and if acid
I add a few drops of a solution of Sodii carbonas. If the
cover-glass is round the cement can easily be applied on a
turntable : if square, which I prefer, one paints it round with
a \ery small brush. This sets in about fifteen to thirty
minutes in a w-arra Toom. When dry I apply o\er it a coat of
Bell's cement, which also dries quickly.

I should be glad to hear of any better cement, but wh.atever
be its nature it must be neutral in reaction.

As regards the optical characters of Parolein, the refraction
index is 1 -471. That of solid Canada Balsam 1 -538, that of
balsam in xylol a little lower, say 1 • 530. The refraction
index of bacteria is s;iid, according to .A. Fischer, to be 1-55.

May, 1011.

KNOWLEDGi:.

193

Now the index of visibility or power of seeing an unstained,
and presumably a stained, structure is greater when the
medium has a very low or a \'ery high refraction index.

Bacteria would be invisible in a medium having a refraction
index of 1-55, in Canada Balsam they would be seen, in
Parolein they would be seen much better, and this theoretical
statement is borne out by experience. V'ery delicate structures
like the flagella of bacteria are better seen in Parolein than in
Canada Balsam.

Mr. E. M. Nelson and Mr. Merlin both state that the
delicate structures, in some bacterial films I sent them, "are
strong and sharp ; in fact, stronger and sharper than in balsam.''

I am not prepared to state that there is no better mounting
medium than Parolein : I should only be too glad to hear of one
that offers a reasonable chance of permanency and which has
as good optical (jualities. All I can say is that at present
every slide that has a place in my cabinet will be mounted in
Parolein ; Canada Balsam has ser\'ed me very badly.

Alfred C. Coles, M.D., D.Sc, F.R.S. (Edin.i.

M.R.C.P. iLond.l.

THE MICROLOGIST.—We have received from the
publishers, Messrs. Flatters, Milborne tt McKechnie, Ltd., of
Manchester, Part 4 of their quarterly journal. TIic Micrologist.
In this part full details are given for the preparation of slides
illustrating the Marine Protozoa, chiefly the Radiolaria — such
types as Sphacrozoum, Anlacantlia and My.xosphaera being
dealt with ; in the latter case the method of infiltrating and
cutting sections of the colony being described. The Amoeba,
its life-history, structure, cultivation and the preparation
of microscopical mounts, is dealt with by Mr. Gordon
McKechnie. It would be an advantage if some indication
were made as to what other organisms can be treated in the
same manner as that described for Amoeba : for instance,
would the same treatment suit Paraiiiocciunt, Stcntor, and
so on ? Included in this number are formulae for stains
and mounting media, which cannot fail to be of use to
the working microscopist. Plate IV illustrates the objects
dealt with and of the slides sent out with this number we
have received two — Amoeba and Sphacrozoum — the latter
making a very pretty object with a low-power and dark-
ground illumination.

QUEKETT MICROSCOPICAL CLUB.— March 28th,
1911. Professor E. A. Minchin. M..A., President, in the chair.
The death of Mr. \V. M. Bywater, F.R.M.S.. on March 1st.
was announced. He was one of the fovmders of the Club, and
its first secretary. — Mr. A. C. Banfield exhibited and described
a new quartz mercury \'apour lamp, manufactured by the Brush
Electrical Company. The cjuartz tube used in the new form
is about four inches in length. The lamp is extremely rich in
ultra-violet rays, and will sterilize a Petri-dish cultivation in
less than one miimte. The peculiar mercury spectrum gives a
unique opportunity of easily obtaining strictly monochromatic
light in large ijuantity. with a choice of several wave-lengths,
that at X 5461 being the most powerful source of monochromatic
light at present available. — Mr. E. M. Nelson. F.R.M.S.,
described the best method of obtaining dark-ground illumina-
tion. Place the buU's-ej-e at right angles to the edge of the
flame. Adjust its height so that the horizontal optical axis of
the bull's-eye cuts the brightest part of the edge of the flame.
Focus the bull's-eye so that a sharp image of the flame
is thrown upon a wall, distant, say. five feet. Place the
lamp, without altering these adjustments, on the left-hand side
of the microscope, and ten to twelve inches from the mirror ;
remove substage condenser and objective, and place a low-
power eyepiece in position. Incline the plane mirror and
adjust the height of the lamp so that the bright part of the
flame falls centrally upon it. Then incline the mirror so that
the full beam is reflected up the microscope tube. From
a distance of six or eight inches look at the bright spot of light
at the eye-lens. This should be an evenly-illuminated bright
disc. Replace condenser and objective, centre and focus
substage i[i usual manner and proceed with the work in hand.

selecting a suitable black stop, one not too large, and a dark
field of maximum brightness for that set of apparatus will
have been obtained. To obtain tn- darkest possible ground
many objectives require the tubs-i^iigth to be increased,
sometimes considerably. Mr. C. Ls2j dirties exhibited, at
Mr. Nelson's request, the lamp and condenser described. —
Mr. A. A. C. Eliot Merhn. F.R.M.S., disca^,sed "Some New
Diatomic Structure discovered with a nev/ Zeiss apochromat."
— Mr. James Murray, F.R.S.E., F.Z.S., read a paper, "Water
Bears or Tardigrada." As the name Tardigiada is already
appropriated by vertebrates the group is now classified as
order Arctiscoida, family Xenomorphidae. The paper
describes four new genera and their relationships, concluding
with a synopsis of the ten genera and one hundred and
twenty species at present admitted. — Mr. M. Ainslie exhibited
and described a " finder " for the microscope, useful with
powers up to about one-sixth of an inch. It consists of a
hinged and pointed arm clamped to one corner of the stage.
When it is wished to record the position of an observed object,
the point is inked and allowed to make a mark on the label to
the left of the object. It is intended for use with either a
mechanical stage or sliding bar.

ORNITHOLOGY.

By Hugh Boyd W.att, M.B.O.U.

BIRDS FROM NEW GUINEA.— The newly arrived
collection referred to in the last number of " Knowledge "
was shown in the Board Room of the Natural History
Museum. South Kensington, on the 5th April, and The Times
of the following day gives a brief report on it. The collection
includes eleven species and several dozen specimens of Birds
of Paradise and their congeners of the crow and starling
group. There are nine examples of the magnificent flame-
coloured Bird of Paradise {Xanthoinelas ardciis) hitherto
represented in Europe by only two specimens in Holland and
an imperfect skin in Genoa. Amongst the larger birds is an
ibis (much like the sacred ibis), and, in addition to the more
distinctively tropical kinds mentioned last month, one or two
sheldrakes and ducks. A familiar British bird occurs in the
form of a young male common cuckoo taken in December
last, presumably on migration from northern regions to
AustraUa. The collection is very rich in the groups of smaller
birds. The genera best represented are sunbirds, flower-
peckers, honey-eaters, and flycatchers, also cuckoo-shrikes,
ground-thrushes and bee-eaters. The material will enable
the distribution of many species to be worked out better than
hitherto ; and results of even more importance are anticipated
from the regions of the great snow mountains which the
expedition hopes to attain, and where the avi-fauna is far less
known than in that part of Dutch New Guinea from which the
collection now under re\^iew has come.

A BLACK EGG.— In Tlie Field of 25th March last, an egg
uniformly black in colour is figured, sent by a correspondent
from his duck-house, where ordinary wild ducks and others
called by him "East Indians" are kept together. The last-
named are described as black, with bottle-green on the wings
and hackles, and are probably the Cayuga duck, which comes
from South America. It is explained that eggs of this
melanistic variety of duck sometimes partake of the colour of
the plumage, but the black colouring does not penetrate the
shell, being due to an oily pigment which can be rubbed oft'.
After successive layings the colour fades and eventually
disappears.

A NOVEL BAIT FOR WOOD-PIGEONS.— Intoxicants
have recently been recommended and tried as an assistance
in getting rid of the wood-pigeon pest. Mr. J. L. Courthope,
M.P., suggests that corn be soaked in spirit and distributed in
the feeding places of the birds, which will eat the grain,
become intoxicated, and then be easily caught and killed. We
believe that gin has been used in some such way in Herts,
with efl'ectivc results.

194

KNOWLEDGE.

May, 1011.

BIRDS IN LONDON AND THEREABOUTS.— Mr. A.
Holte Macpherson contributes his welcome annual " Notes on
London Birds" tlQlOt to Tlic Sclbonie Magazine for April
(pages 96-971. These notes have now continued for twenty-
one years without a break, and are of much value as giving
personal observations, mostly in the West-end parks. The
literature of London birds is an extensive one. but it is to be
hoped that Mr. Macpherson may be induced to publish a
review or survey of his obser\ations in a more permanent
form. Instructive comparisons would not be a-wanting in it.
In the course of 1910, a great crested grebe was seen on the
Serpentine on 29th January, and another on the Round Fond.
Kensington Gardens, on 11th July. Mr. Macpherson had only
once seen this fine species in London previously, and points
out that it is remarkable how it has increased near that city
during the last few years. Virginia Water and Richmond
Park are nam«d as haunts of the bird, to which we would add
Ruislip Reservoir. Greater London holds within its area the
" Brent Valley Bird Sanctuary," an account of which is pub-
lished in a small work under this title by Mr. Wilfred Mark
Webb. Honorary Secretary of the Selborne Society, of which
a third and revised edition, profusely illustrated, has just been
issued (The Selborne Society, 42, Bloomsbury Square, London.
W.C., 34 pages, price 6d., or in paper boards, !■), The
Sanctuary has been maintained now for about six years with
results which redound to the praise of the Committee who so
vigilantly look after it, and are gratifying to all who care for
our native birds. Nesting boxes, made on the spot, have
been used since 190S as a method of attracting birds and
have proved iiuite successful, being largely used. Within this
limited area of nineteen acres, possessing no outstanding
natural advantages, thirty-six species (almost entirely smaller
woodland birds) have now nested, and eighty-six species in
all, including occasional visitors, have been observed in or
close to the place.

A MIGRATION "RUSH."— The Irish newspapers report
that a migratory movement of an extended character was
observed on 29th-31st March, conspicuously in South-east
Ireland. The weather conditions were still and dark, the
moon being in her dark phase, and at the same time fog
prevailed. These conditions are conducive to migrants
showing themselves. The migrating flights seem to have
been attracted by the lights of the towns, just as they often
are by lighthouses. In New Ross a swarm of starlings
descended on the town about ten o'clock and the streets
were littered with them. House-windows were broken and
numbers of birds entered the houses. In Kilkenny many
hundreds of birds fell dead in the market-place and else-
where. In Carlow the destruction which befel the birds is
said to have been caused by them coming into contact with
telegraph and other wires. Immense flocks of Curlew passed
over this town on the night of 29th March, in a N.E. direction,
being recognised by their shrill whistling.

The other kinds of birds named in the reports are thrushes,
blackbirds, redwings, and sparrows, but, no doubt, many
species were unrecognised. Amongst them probably occurred
some of our first summer visitants for this season.

CROSSBILLS IN THE BRITISH ISLES.— An account
of the irruption of crossbills which took place in 1909, is given
in the April number of British Birds (Vol. IV. pages 326-331).
First observed at Fair Isle, on 23rd June. 1909, the arrivals
continued until about 10th August. The birds appeared
rather later in southern districts than in the north, and by the
latter part of July their numbers were decreasing in Scotland.
In England they were much in evidence during July and
increased until well into August. During the winter they
were recorded from all the English counties except
Cumberland, Notts, Huntingdon, Cambridge, Dorset, Devon
and Cornuall ; and in Wales from Denbigh, Merioneth,
Montgomery and Brecon. It is remarked that records are far
more numerous from the country lying to the south and east
of a line drawn from the Wash to Portland Bill, the sandv
soils occurring therein being much planted with pine trees.
These trees pro%ide natural food supply for the birds.

Nesting was recorded as early as 12th January. 1910, near
Thetford, Norfolk (three nestlings), and the latest records are
25th May, from Sussex and Kent. .All the nests known were
in Scots pine, except two in spruce and two in larch. Only a
small proportion of the visitants nested, the following counties
yielding records, viz: — Kent. Sussex, Surrey. Hants, Berks,
Essex (two), Suffolk, Norfolk, Somerset (one), Gloucester, and
Stafts (one), also probably Lincoln and Bedford.

The departure of the birds began in the winter of 1909-10,
and this movement was at its maximum from February to
June, with a few records for later dates. The visitation thus
extended over a period of rather more than twelve months.

It should be added that the bird spoken of is now designated
by modern ornithologists as I.o.xia ciirvi rostra ciirvirostra
— the Common Crossbill.

Mr. H. F. Witherby follows the paper above summari/:ed by
an article (pp. 332-334) on its status as a British bird, of which
the following is an abbreviated summarj', viz.: —

England and Wales. — An early autumn inunigrant
(mid-June to August), irregular in most districts. Periodically
(every three to ten years) arrives in great numbers, and
becomes much more generally distributed, frequenth' staying
over the following spring and into summer. .Authentic records
of nesting are so few and far between that the bird cannot be
classed as a resident, but only as a migrant, breeding
sporadically (nesting counties are named by Mr. Witherby).
Crossbills have been found this spring (1911) to be breeding in
localities in which they bred last year, the first time they are
known to have nested in two successive years in the same
district.

Scotland. — Immigrant as in England, but not so regular.
Breeds sporadically and rarely in Southern Scotland (counties
named).

Ireland. — Now resident but not indigenous. Apparently
only migrates to Ireland in years of " irruptions." Following
that of 1SS7-S became established as a breeding bird.

The Scottish Crossbill, Loxia ciirvirostra scotica Hart,
which is confined as a breeding bird to Scotland, is
resident in Northern Scotland, where it breeds in certain
localities (named). Has occurred sporadically in winter in
\ery small numbers in Southern Scotland (counties named).

PHOTOGRArHY.

By C. E. Kenneth Mees, D.Sc, F.C.S., F.R.P.S.

THE MEASUREMENT OF S U R F ACE
BRIGHTNESS. — Under this title a paper was read at the
Royal Photographic Society, on March 28th, 1911, by
Messrs. J. S. Dow and V. H. Mackinney, describing a small
portable photometer under the name of the " Holophane
Lumeter." which is intended for the measurement of the
intensity of the light reflected from various objects.

In the instrument, the surface whose brightness is to be
measured is observed through an aperture in a white opaque
surface, the discs surrounding the aperture being illuminated
by means of an opal glass behind which is an Osram lamp,
run off an accumulator. The area of the opal glass can be
restricted to any required extent by means of black sectors,
and the intensity of the illumination read to one per cent, by
means of scales, the maximum opening representing an
intensity of one foot candle.

The accuracy claimed for the instrument is about five per
cent., which will clearly be sufficient for most practical
purposes.

By means of two supplementary black glasses the light
from the external surface can be cut down to one-tenth or
one-hundredth of its original amount, and the maximum
intensity measurable can thus be made ten or one hundred
foot candles.

This range seems to me insufficient, and it would probablv
be better to add other densities to extend the scale to one
thousand and ten thousand foot candles.

May, 1911.

KNOWLEDGE.

195

The instrument, in use. appears to be very convenient, the
greatest difficulty in photoi^raphic use, however, being due to
the colour effect of daylight, which makes matching distinctly
difficult. It is possible that this might be completely avoided
by the aid of an orange screen to tint the daylight beam,
but such a screen would require careful adjustment.

There are numerous directions in which such an instrument
can be of use in photography ; in the first place, it is obviously
of importance to know the range of contrast which exists in
photographic subjects, and this is a point on which hitherto
experiments ha\e been difficult to make, and on which \iews
of considerable diversity have been expressed.

Messrs. Hurter and Driffield measured the maximum

t

Figure 1.

difference of intensity in landscape subjects by taking a
photograph of a scene in which was included a square of
white cardboard in sunlight and a piece of black velvet in
shadow ; the plate was developed together with another plate
from the same box which had been exposed behind a sector
wheel to a candle, and the densities of the patches representing
the white cardboard and the black velvet were measured and
compared with the densities of the known exposures on the
other plate. As a result the white cardboard in sunlight was
found to reflect thirty times as much light as the black velvet
in shadow.

In their paper, Messrs. Dow and Mackinney mentioned that
the maximum range of intensity which they had measured in
a subject between the brightest white magnesia and the
darkest dead black which they had been able to obtain w-as as
thirty to one : so that apparently the result obtained by Messrs.
Hurter and Driffield for the maximum range in ordinary
photographic work may be considered as confirmed.

Some measurements made by means of a similar, but much
less convenient, portable photometer two or three years ago.
gave the writer only one to four as the range of intensity in a
street scene on a dull day. so that probably the range in most
landscape photographs is of the order of one to eight or
one to sixteen, a range which is capable of being represented
within the " period of correct exposure " of a plate.

.\nother use for the instrument, suggested by the authors

of the paper, was the finding o» exposures, and although
several speakers in the subsequent discussion considered that
the variation in the actinic value of daylight would make the
instrument of but little value in this direction, it seems to me
that in some branches of photography it should prove of very
great value indeed.

While it is im-
probable that such an
apparatus, which is
necessarily of some
size, will displace the
handy and simple
sensitive paper actino-
meter for landscape
work, yet in the
technical studio it has
many advantages. In
copying prints by day-
light in this climate
difficulty is often in-
troduced by the rapid
variation of the light
while working ; even
if the first exposure
pro\ e quite correct on
development, the light
may change sufficiently
to spoil it before a
second exposure is
made.

The use of an
actinometer in such
work is almost im-
possible because of
the time required for
the exposure of the
actinometer paper, but
the ■■ Lumeter,"' which
enables a measure-
ment to be taken in a
few seconds, would
probably save man\-
plates. In black and
white work, again,
where what is required
is the maximum ex-
posure which can be
given without pro-
ducing any deposit in
the parts of the plate

representing the blacks in the original [all that jwould rbe
required to render the calculation of the exposure absolutely
mechanical would be to find out what exposure to one foot
candle for a given plate and stop would just fail to produce
an impression upon the plate, and then make a measurement
of the light reflected from the blacks of each subject.

In enlarging, also, a measurement of the light falling upon
the enlarging easel through the densest parts of the negative
should, after one or two preliminary trials, enable the correct
exposure to be calculated with considerable ease.

A HYDROSTATIC APPARATUS ILLUSTRATING
THE LAW OF DEVELOPMENT.— The development of a
photographic plate proceeds according to the equation which
represents what in chemistry is called a mono-molecular
reaction of the first order, although development is. of course,
a heterogeneous reaction, of which the surface of the silver
bromide is the \ariable. The law of de\elopment is
very simple, and is, that the rate of development at an\- time
is equal to a constant to the difterence between the ultimate
density that can be obtained if the development be indefinitely
prolonged and that which already exists, that is: Rate =
Constant iDco— D).

In order to make this plain a little piece of apparatus can
be made which supplies an almost perfect analogy. It consists

Figure 2.

196

KNOWLEDGE.

M \v. I'Ml.

of a glass cylinder, to the bottom of which is attached a piece
of glass capillary tubing, and then a piece of thin glass tubing.
bent so as to be vertical like the cylinder (Figure 1).

A coloured solution
is put into the cvlinder,
and then by turning on
the tap it passes
through the capillary
and rises in the vertical
tube until the level is
the same as that of
the liquid in the
cylinder. The rate of
rise in the vertical tube
IS rapid at first, and
then becomes slower
.ind slower until the
level is attained.

A measurement of
the time taken to rise
one centimetre, when
the difference between
the level in the tube and
that in the cylinder
was twehe centimetres,
gave fifteen seconds.
When the difference of
level was six centi-
metres the time was
thirty seconds, and
when the difference of
le\el was three centi-
metres the time taken
was sixty seconds ; so
that if H is the height
in the cylinder, and h
the height in the tube :
]\ate of rise is pro-
portional to H — h,
or : Kate = Constant

IH-h).
We see that for this
.apparatus H exactly
I finesponds with D oo,
the ultimate density of
a plate, and h corres-
])iinds with D, the
density already at-
tained.

Just as the constant

for the glass apparatus

depends on the size of

the capillary, so the

constant for development depends on the rate of penetration

of the developer and the products of the reaction through the

film, or the diffusion.

In general, however, when we deal with the development of
a plate, we ha\e to deal, not with one exposure, but with many
different degrees of exposure received on different parts of the
plates and giving rise to different ultimate densities in these
parts.

In order to see the effect of this we may construct another
simple apparatus (Figure 21 consisting essentially of three
separate apparatuses similar to that described above, three
identical tubes being arranged in front and connecting by means
of identical capillary tubes with three cylinders at the back but,
these cylinders are arranged so that the heights are variable,
and three different heights, HI, H2 and HJ, are given to the
three tubes. Now if we start this apparatus we shall find that
h2 rises faster than hi, and hi faster than h2. In fact, while
at first the levels in all three tubes were equal, after they have
risen the levels are very different, the level of h2 being above
that of hi, and h3 higher still. Figure 3 shows the apparatus
after the levels have risen.

Transferring this to a plate with three different exposures

IKt

cap.able of giving ultimate densities Dl, D2 and D3. we see
that it will mean that while at first they are all e(|ual. as
development proceeds the contrast between dl,d2 and do will
iticrease until finally an ultimate contrast will be reached,
dependent on the value of 1)3.

In order to measure the contrast between the levels in our
three tubes the most obvious thing to do is to draw a line
through the three points. The slope of this line will then be
a measure of the contrast, and clearly the rate of increase of
slope will be proportional to the difference between the
ultimate steepness attainable and the steepness already
attained.

PHYSICS.

P.y A. C. G. Kgkrtox, B.Sc.

RAYS OF POSITIVE ELECTRICITY'.— Professor Sir
J. J. Thomson gave a lecture on a " New Method of Chemical
Analysis," on Friday, 7th April, at the Royal Institution.

If an electric discharge is passed through a large vacuum
tube whose cathode is a tube of fine bore, positively charged
particles stream back from the cathode mo\ing in the opposite
direction to the cathode rays. Sir J.J. Thomson has made a
thorough investigation of these rays, which were called by
Goldstein, their discoverer, "' Kanalstrahlen." The apparatus
employed to study these rays, consists essentially of two glass
vessels connected by a narrow tube : the cathode is a fine bore
metal tube provided with an ebonite plug which fits the tube
connecting the two vessels. The one vessel is the discharge
tube, the other the observation tube ; the anode is situated
at the side of the discharge tube. The discharge tube is made
very large, so that a high potential discharge can be passed
through the tube at very low gas pressures without danger of
puncturing the glass tube. Cathode rays stream away from
the cathode into the discharge tube. " Kanalstrahlen " stream
through the fine tube, which constitutes a portion of the
cathode, back into the observation vessel. Here they ha\'e
to pass through a powerful magnetic field and electric field, so
arranged that the magnetic field deflects them vertically, and
the electric field horizontally. They impinge after undergoing
this deflection on to a photographic plate or a willemite screen ;
the former is affected by the rays and registers their position
and intensity, the latter by the phosphorescence set up gives a
visible impression of their deflection.

The deflection of the rays is such that they may be divided
into two classes — primary and secondary rays. The primary
rays give short parabolic arcs having their heads in the same
vertical line, which shows that the minimum electrostatic
deflection undergone by the particles is the same whatever the
nature ot the gas. This means that the maximum potential
difference through which the particles have fallen is the same,
or that they take their origin close to the cathode. The
secondary rays are produced by the primary rays in their
passage through the gas in the observation tube, and their
position of formation can be found by altering the distance
through which the primary rays are under the influence of the
magnetic and electric fields. Sir J.J. Thomson has found in
this way that the secondary rays are due to dissociation of
systems in the undeflected Kanalstrahlen, due to collision with
negatively electrified corpuscles, giving rise to a negatively
electrified and a positively electrified portion. The reverse
can also take place within certain velocity limits, namely the
collision of a positive ray with a negative corpuscle and
consequent production of an tmcharged particle. The study
of the shape of the curves produced by the action of the
particles on the photographic plate shows that either of these
two actions may occur.

Sir J. J. Thomson, in his lecture at the Royal Institution,
pointed out how the results of this investigation may be
applied to develop a new method of chemical analysis, which
is applicable to minute quantities of vaporisable substances,
and which, without the necessity of using pure materials, will
give directly the atomic weights of the substances under
investigation. For the relative positions of the ends of the
small parabolic arcs due to the primary rays are proportional

May, 1911.

KNOWLllDGE.

197

to the masses of the particles constituting the rays. Further-
more, the velocity of the rays is so great that the production
of particles not completely stable under ordinary circum-
stances are enregistered on the plate.

Professor Sir J. J. Thomson has been able to obtain
evidence of the momentary existence of CHi, CH>, and CHi.
Furthermore one gas does not necessarily give rise to only one
type of ray, but one parabolic arc may be due to the atom
with two positive charges (^o /• another to the atoin with a
negative charge (5) or a positive charge (q), another to the
molecule (o.,), another to a more complicated molecule (o,)-
or more complicated still (cjj). It appears that a negatively
ch;irged molecule is not obtainable easily, because in the
molecule the electrons are more firmly bound and held together
by their nnitual influence, whereas in the atom they are freer ;
consequently, when a collision occurs with a negative corpuscle,
the latter may attach itself to the atom but not so easily to the
molecule. Sir Joseph Thomson illustrated this point in his
lecture by recourse to a simple experiment with magnets.
Compass needles were balanced on points on a card, suspended
from the roof, which hung close to a magnet. When the
compass needles were free to move, the whole card was
attracted by the magnet : when the compass needles were
removed and laid at random on the card, the latter was not
attracted to the same extent.

This new method of analysis, by means of high vacuum
discharges, will be excessively valuable in investigating the
charges which more complicated atoms undergo and will
no doubt lead to many new discoveries and unlock the
secrets of the atom. Strange lines appear in these spectra
which are not readily explainable.

{c.}>. 65 possible """h, )

ACTIVE NITROGEN.— Professor R.J. Strutt delivered the
Bakerian Lecture on April 6th to the Royal Society. The
subject of his lecture was the afterglow from the passage of
the electric discharge through nitrogen. We mentioned it in
the Physics Notes for February. If pure nitrogen be passed
through a discharge tube continuously at a low pressure by
suction with a Grede pump, on leaving the discharge tube, it
glows with a yellow light and is highly active. It combines
with iodine causing the latter to glow brilliant blue, gives a
compound with phosphorus — that which is no doubt produced
during the exhaustion of Sir OUver Lodge's high tension
valves by means of phosphorus — and causes the metals,
when warmed sufficiently to give off vapour, to emit light
giving their characteristic line spectra. Professor Strutt
illustrated this point in a most beautiful manner by showing
the green glow emitted by a small piece of thallium placed in
the tube through which the active nitrogen passed. Professor
Strutt considers the nitrogen to be in the atomic form.

SEISMOLOGY.

By Charles Davison, Sc.D., F.G.S.

THE RECENT ERUPTION OF TAAL VOLCANO
IN THE PHILIPPINE ISLANDS.— In the island of Luzon,
nearly forty miles south of Manila, lies lake Bombon. Near
the centre of this lake, from Volcano Island, there rises Taal
\'olcano. which, by its eruption last January 30th, caused so
nmch damage to the surrounding villages. The crater walls
vary in height. At no point are they lower than four hundred
and ninety-two feet, at the highest they rise to nine hundred
and ninety-six feet.

When the United States Government took over the Philippine
Islands at the close of the last century, they acquired the
services of a Jesuit priest, the Rev. M. Saderra Maso, who for
many years had studied and published valuable reports on the
earthquakes and volcanoes of that unstable group of islands.
Being appointed an assistant-director of the U.S. Weather
Bureau. Father Saderra Maso has continued his useful
work, one of the latest results of which is the investigation
of the recent eruption of Taal Volcano. Of his interesting

report on this eruption a summary ii given in the present note.
During the night of January 27th-2Sfn, the volcano issued the
first warnings of the coming eruptio:"-. Instead of the usual
clouds of white steam, great puffs of biack smoke were emitted
from the main crater, accompanied by rumbling sounds and
tremors. On January 28th and 29th, explosions and earthquakes
became more frequent and stronger, until at about 2.20 a.m.,
on January 30th, they culminated in a tremendous explosion,
the sound of which is said to have been heard at a distance of
two hundred and fifty miles. .A huge black cloud rose from

-f

>s<r

''"^^~' \f)

+/^

L

^ ^

A K E J

V <

^ /

2

T^V "^1/^

^

\ ; rCRATTER ^ \

1

WoLC^NjJ /

•V

U-^ f

-f /b
1 1

O M B O N i

FiciRi: 1.

the crater, lit up by flashes of lightning, vivid sparks and
bursting globes of fire. .A heavy fall of boiling mud followed
the explosion, and destroyed all the vegetation and the flimsy
houses on Volcano Island and along the western and north-
western shores of the lake to a distance of ten miles from the
crater, and caused the death of between one thousand two
hundred and fifty and one thousand three hundred of their
inhabitants. On the accompanying sketch-map. reproduced
from Father Saderra Maso's report, the black dots indicate
the towns and villages that were obliterated, and the small
crosses those that were damaged.

After the eruption, there was a rush of air towards the
volcano, which was noticeable for many miles around.
Barometers registered a rapid fall of atmospheric pressure,
which at Batangas (seventeen miles from the volcano)
amounted to about one-twelfth of an inch, and at Manila
(thirty-nine miles) to one-twenty-fiffh of an inch.

The distribution of the volcanic mud was governed by the
direction of the prevailing wind, which was from the south-
east. On Volcano Island and the western and north-western
shores of the lake, the mud formed a layer from two to three
feet in thickness. With increasing distance, its thickness
gradually diminished, until beyond a distance of fifteen miles
only grey gritty dust was deposited. The finer dust was, of
course, carried still farther, and, on the morning after the
eruption, some fell at Manila. On the south-eastern shore
of the lake no mud was to be seen, and only a little was
deposited on the eastern and north-eastern shores.

.Vfter the great eruption of January 30th, no other outlim>-t
of anv importance took place, and the earth(]uake-shocks soon
diminished both in frequency and strength until they prac-
tically ceased on February 7th.

Along the shores of the lake, the damage was increased by

198

KNOWLEDGE.

May. 1911.

the waves produced in the lake, which reached a height of ten
feet. Here and farther inland, some injury was caused by
earthquakes, more by the continual shaking than by the actual
strength of any shock, for none of them attained a destructive
degree of intensity. At the observatorv of Manila, nearly one
thousand shocks were recorded between the evening of
January 27th and February 7th, none of which in that city
reached an intensity greater than the fourth degree of the
Rossi- Forel scale of intensity. In other words, the strongest
were capable of m.iking doors, windows, fireirons, etc., rattle ;
they produced a trembling sensation like that felt on a station
platform when an express train passes. Other shocks, of the
third degree, were just sufficiently strong to be felt by human
beings. The great majority of the shocks were of the second
and first degrees of intensity ; they were microseismic move-
ments requiring rather delicate instruments for their detection.
The following table, founded on that given in Father Saderra
Maso's report, shows the number of shocks of each degree
registered at Manila from 11.6 p.m. on January 27th to
Februarv 7th.

Intensity (Rossi-Forel Scale).

4

3

2

1

Januarv 27

28

29

30

31

February 1

2

" 3

4

5

6

„ 7

10

9

.S

16

12

4

"o
1

2

21

9

10

16

11

3

2

2

1

3

31

28

16

28

18

9

7

3

3

1

...

21
135
67
62
139
89
61
46
il
23
14
11

It will be noticed that the shocks were most frequent on the
day following the beginning of the eruption and on that after
the great explosion. .\s this occurred at 2.20 a.m. on January
30th, it is evident that the explosion caused a temporary relief
of the internal strains, such as might well gi\'e rise to the old
view according to which volcanic eruptions were the safety-
valves that shielded us from earthtjuakes,

ZOOLOGY.

By Proi-essor J. .Arthur Thomson, M..A..

BIRD - M.ARKIXC,. — The .Aberdeen University Bird-
Migration Inquiry, of which Mr, A. Landsborough Thomson
is the Secretary, aims at collecting more definite information
on the subject of the Migration of Birds by means of the
method of placing rings on the feet of a large number of
birds in the hope of hearing of the subsecjuent nunements of
some proportion of them. To this end the rmgs .u'c inscribed

with the address " .Aberdeen University," and a number lor
number and letter combination) different in each case. The
rings are placed on young birds found in the nest, or on any
old ones that can be captured without injury. The rings are
of aluminium and extremely light, and do not inconvenience
the birds in any way. The marking work is chiefly carried on
in Scotland, notably in .Aberdeenshire, but is not confined
thereto. The Inquiry has the support of Mr. J. A. Harvie-
Brown. Mr. W'm. Eagle Clarke. Mr. W'm. Evans, and other
well-known Scottish ornithologists, and similar In<iuiries exist
in England and abroad.

The coi)peration of all who take any interest in Natural
History questions is earnestly solicited in order to secure the
best results : —

1. It is particul.irK- requested that all «ho nia>- hhoot.
capture, or kill, or e\en hear of any of our marked birds should
let us know of the occurrence. .As accurate particulars of
date and locality as possible are desired, but, above all, the
number (or number and letters) on the ring. Indeed, except
where it has been possible to reliberate the bird uninjured, the
ring itself should always be sent ; or the ring and foot, or even
the whole bird. We always refund postage if asked to do so.

2. Cooperation is invited in the actual work of marking,
of any who are specially interested, and have some knowledge
of birds, and also time and opportunity for the work. The
necessary rings, schedules, and postage stamps, are supplied
by us without charge, and we undertake to let the marker
know of each case of a bird marked by him being recovered,
and to let him have copies of printed reports so far as
possible.

The following results obtained at an early stage of the
work will ser\e to indicate what is to be expected from it ;
these are merely a few records which happen to be of con-
siderable individual interest : —

A Widgeon duckling [Marcca pen dope), one of fi\i;' marked
in June, 1909, on Loch Brora, Sutherland, Scotland,
was taken in a duck-decoy in Province Groniugen,
north-eastern Holland, on 3rd September. 1909. This
bird was thus only three months old when it was found
more than 500 miles from its birth-place. .A second
member of the brood was shot on the Trent, near
Retford. Lincolnshire. England, in January, 1911,
lia\ing wiirn the ring for a year and a half,

.An adult Swallow \Hinindu nistica) caught and marked
at a farm near Tunbridge Wells, Kent, England, in
June, 1909. was re-caught at the same farm in
June, 1910.

Five Lapwings iVanelliis vulgaris) marked as chicks in
the North-east of Scotland, in the summer of 1910,
were shot respectively in Counties Tipperary,
Roscommon, Cork, and Limerick, Ireland, and in
Southern Portugal, during the winter 1910-11,

,A Song-Thrush iTiirdiis nii(siciis), one of a brood marked
as chicks in the nest at Skene, .Aberdeenshire, in early
June, 1910, was shot near Leiria, Portugal, in early
November of the same year. The localities are about
one thousand two hundred and fifty miles apart.

DISCS FOR SOL.XR PR( )J I':CTION,
By JOHN McH.VRG, M,A.

In the series of maps for solar projection of which an example
is printed on the following page, the graduation to intervals of
10 in latitude and longitude is only carried to the fortieth
parallel of latitude. For convenience in estimating the
diameters of sunspots, a portion of tlTE central meridian is
divided into degrees, one of .which is equal to seven thousand
five hundred and fifty-four miles. The heliographical latitude
of the centre and the position-angle of the solar axis are
considered positive, the former when the North Pole is tilted
toward the observer, and the latter when it is inclined from
the north point toward the east ; this happens on the dates
when the directing lines at the right-hand side of the map are
above the equator. It will be observed that with the exception
gf a brief period about the time of the solstices, the above

quantities have the same sign throughout the rest of the year.
The solar image, when projected on the disc by a refractor
provided with an astronomical eyepiece, suffers reversal from
left to right, after the fashion of images in a plane mirror or
that of the sun in a diagonal. The correct position-angle of
the disc may be easily obtained by stretching a hair tightly
across the field of the eyepiece a little beyond its focal plane.
This is then turned till the image of a spot runs along the hair,
or in its absence by depressing the image till a mere thread of
light remains above the crossvvire. The coincidence of
ecfuators of image and disc is then secured by causing the
appropriate directing line on the disc for the date to coincide
with the image of the crosswirc, intermediate positions to those
gi\en being supplied by estimation or measurement.

\'. Latitude of Centre + 4°

199

REVIEWS.

AEK(_).\AL'TICS.

l-:iciiuiitiiry Acroiiiiutics. — By A. P. Thukstox. 1^6 pages.
126 illustrations. Sl-in. X 5J-iii.

iWhittaker ^: Co. Price 3 6.)

Auvtliiuy from the pen of Mr. Thurston, the able associate
of Sir Hiram MaNini in his later experimental work, nmst of
necessity be of interest, and the book having the above title
bears this out. The book abounds with up-to-date e.xperi-
mental results and diagrams relative to curved surfaces.
Although a few of them are chiefly of academic interest most
are of a highly practical value.

Another interesting feature is the large number of reproduc-
tions from photographs of artificial stream lines formed from
cloud vapour of ammonium chloride. The author introduces
some new work on stability although he would appear to have
overlooked one important aspect of the problem. We all
thank Mr. Thurston, and congratulate him on giving us this

book.

T. W. K. C.

suggest that this book was principally intended, it still leaves
much to be desired, hardly half-a-dozen pages being devoted
to constructive detail. On page S4 the author rightly alludes
to the fine construction of the Antoinctfc Monoplanes but
refers to the figure on the opposite page which is of a Wright
Biplane, the very antithesis of construction. We had hoped
to see this error in the first edition corrected in the second.
Perhaps the translators will see to this in the next edition. In
other respects they have done their work very well indeed.

The book is written in plain language, clearly printed on
good paper, and sold at a popular price. It will, we are sure, be
widely read. -i- ,.• ■- ,-

'' Biri!,niii!il as the Basis of Aviation:'— By Otto
Lll,lENTH.4L. With a biographical introduction and addendum
bv GUST.WK LlLlEXTH.\L. Translated from the second
edition by A. W. Isenth.\l, A.M. I.E., F.R.P.S. With a
portrait. 142 pages. 94 illustrations, and 8 litho plates.
Qi-in. X 6J-in.

(Longmans. Green & Co. Price 9 - net.)

The Theory and Practice of Model Aeroplaning. — By

\'. E. Johnson. M..A. 14S pages. 61 illustrations.

7i-in. X 5-in.

(E. & F. N. Spon. Price 3 6 net.)

There is nothing but praise to dispose upon this little book.
The author has modestly dedicated it to those interested in
the minor branch of model aeroplaning, but there is no student
in anv branch of aeronautical engineering who will not learn
something from this book. E'rom end to end it is full of
reliable information. Great pains have been exercised to
exclude not only misleading but doubtful matter, and there is
a complete absence of all " padding."

.Although written in simple language and without a mass of
mathematical formulae, it is yet the most truly scientific work
on model aeroplaning that has yet appeared, and one that all
taking interest in this subject must obtain. -.. ,,, j. p

l^rinciples of Aeroplane Constrnetiou. — By Rankin
Kennhdv, C.E. 137 pages. 50 illustr.itions. SJ-in. X SJ-in.

(J. & A. Churchill. Price 5 - net.)

A considerable amount of this book might \sitli advantage
have been omitted, being based on a somewhat doubtful mass
of mathematical work and out of date methods.

This criticism does not apply throughout, for in the second
half the author discusses the propeller and especially the
Helicoptere in a very lucid manner, disposing of some of
the fallacies concerning the latter, with some well-timed
remarks. On the whole this book. I think, might be described
as ■■ not sufficiently up to date." .|. ^^. j^ ^

Hou- to liiiilil an Aeroplane. 2nd edition. By KoHERT
Petit. IKS pages. 93 illustrations. fSJ-in.x 5.]-in.

(Williams & Norgate. Price 2 6 net.)

Thin book has reached its second eclilinn. Ihr translators
have taken the opportunity to correct several errors which
crept into the first edition and it now forms a very concise
little book dealing with aeronautical design. Considered from
the point of view of the " builder," for whom the title would

.At the present time, when so much interest is taken in
.Aviation, the publication of a second edition of Lilienthal's
well-known book on " Birdflight " is very appropriate. The
translator claims, we think with justice, that Lilienthal was the
Father of gliding experiments. He is almost the Father of the
aeroplane, since it is quite evident that the experiments upon
gliding led to the practical development of the aeroplane. We
believe we are correct in saying that it was in experimenting
with a power-driven glider that Lilienthal, unfortunately, lost
his life. The translator has done his work very well. It is
diflicult to find any of those slips in translation that are
sometimes only too much in evidence, particularly when the
original is in German. The idioms in German and French
are often very difficult indeed to give the English equivalent of;
and the translator too often gives a literal interpretation, which
is oftentimes almost nonsense. In the present instance, the
translator understands his subject thoroughly : he is an
enthusiast also, and we believe he has given us what the
master wrote.

The appearance of Lilienthal's book also, is of peculiar
interest just now, when the Ornithopter, which should be a
direct copy of bird wings, and so on, has so far not been
able to obtain even a very small footing in the aviation
world. The practical construction of Ornithopters has been
announced, and the usual claims made for them, which
according to Lilienthal's investigations should be maintained ;
but they ;ippear to get no farther. Lilienthal made a very
careful study of birds at first hand ; and the book before
us is full of very useful inform.ition, indeed, upon the mechan-
ism of birds' wings, how the bird uses them ; and in particular,
the action of the wings of sea birds. He appears to have
made a very exhaustive study, not only of the birds that
we find flying over our fields, but also of those sea birds — the
albatross, the sea gull, the stormy petrel, and others — whose
flight is apparently so different to that of the land birds.
Sea birds are able to rise vertically from the ground, accord-
ing to Lilienthal, and to maintain flight against the wind,
without any exertion whatever. He evidently looked forward
to the day when man would be able to do the same. It is,
perhaps, interesting to note tliat the development of the
aeroplane, so far from being in the direction of reduced
power, is going lu-adlong to the opposite extreme. The early
.aeropkuies were c<|uipped with engines of 25 H.P. : those a
little Later at 35 H.P., and the figure has steadily increased,
till the m.icliines which have done the best work in a certain
sense, during the last few months, have been equipped in

200

May. 1911.

KNOWLEDGE.

201

engines of 100 H.F. : and aviators and engineers who are
catering for a\iators' wants are scheming to produce engines
of larger and larger horse-power. Aviators are impressed
with the well-known law, that the pressure supporting an\'
given surface varies directh' as the square of the velocity of
the machine through the air, or what amounts to the same
thing, of the air past the machine. Unfortunately, there is
another law. viz.. that the power required varies as the cube
of the velocity. Lilienthal believed in reducing the power,
and we believe that a careful study of the experiments he
made, and of the laws which he worked out, will lead to a
reduction of power, and to a real advance in aeroplanes, on
the lines upon which he worked.

Inventors of aeroplanes appear to have availed themselves
to a considerable extent of the facts which his experiments
brought out, but to have parted company with him at a certain
point. Possibly in a little while the course may be reversed.

We heartily recommend the book to anyone who wishes to
get a sound knowledge of the principles of bird flight, and of
the classical experiments that Lilienthal made. ^ .- ...

.A.STKONOMV.

Ainiiiiiii\s Astrdiioiiiiijucs pour I'll! ct 1912 de I'Observa-

toire Royal de Belgiquc public par les soins de G. Lecoin'TI:.

liirecteur Scientifique du Service .A.stronomique. lyil — 299

pages: 1912 — 167 pages l7-in. x 5-iu.i

These well-known .Annuaires, which ha\e been published
each year since 1S34 without interruption, give in an accessible
form practically all the astronomical data required by amateur
astronomers together with considerable meteorological and
magnetic data often required by practical astronomers.

There is no work in English which corresponds to these
.\nnuaires, but most astronomers have felt the need of such
handbooks which give in a concise form, without the
academical detail of the Nautical .Almanac, the chief
observable phenomena.

Each edition contains a useful map of the world illustrating
the time zones and showing which coimtries have adopted the
standard time system.

The Annuaire for 1912 is specially interesting as it
summarizes the observations made upon Halley's comet from
the date of its re-discovery in 1910 and four plates illustrate the
comet's changes during the period it was under obser\ ation. .'\
further plate shows a star chart with the path of the comet at the
time of inferior conjunction and now that the elements of the
comet are so well known it may be possible to at least trace
the comet photographically through a much longer period than
has ever been done before.

The Annuaires are fairly comprehensive and e.xplanatory
and can be recommended as a useful " companion " to
practical observers. ... j.

BOTAXY.

1 1 I Tlic Livcricurts, British and Forci<^:t. — By Si R Ed\v.\rd
Fkv. 74 pages. 47 illustrations. 7|--in X 5-in.

D.win W'lLso.N.

Willidiii Tlioinsoii — Lord I\ch-iii. — By
56 pages. S'-in. X j.j-in.

(Glasgow : John Smith & Son. Price 2 - net. cloth ;
1 - net, paper.)

Reviewing books would be a very pleasant pastime, if they
were all so fascinating as this one. It is thoroughly enjoyable
— delightfully original. Much sound philosophy and a true
glimpse of a great man of true scientific spirit is included in
fifty-six pages of real literature abounding with amusement.
Read how Lord Kelvin was the " righteous soul in harmony with
things in general." There is a chapter which ends " failing to
realise the deep and irresistible power of capillary (and other l
attractions " ! 'I'here is no doubt as to the deep attractiveness
of the book. . ^ ^

A. C. E.

(Witherby & Company. Price

r.et.

211 pages.

(21 Mosses and Liverworts. — By T. H. Russi;i.i
10 plates. Si-in. X 5.*-in.

(Sampson Low & Company. Price 45 net.)

These two books are alike in many respects. Both attempt
to deal in a more or less " popular " style with a remarkable
group of plants, which has, by many botanists, been regarded
as occupying a central position in the vegetable kingdom, and
forming a transition from the green algae on one hand and the
great fern and flowering plant alliance of the vascular plants
on the other. This group, the bryophyta, has, until recentlv,
been divided by general consent into two classes — the Liver-
worts and the Mosses — though there are signs that this twofold
division is breaking up and will be replaced by a more scientific
system of classification based upon the results of recent work
on the morphology and development of these interesting plants.

(1) Sir Edward Fry's little book is chiefly a mixture of
borrowings from ancient and modern authors, and cannot be
said to present anything like an accurate view of the structure,
biology, classification and relationships of the Liverworts.
The extremely small portions of the book that appear to be
based upon the author's own studies are chiefly remarkable
for eccentric spellings, such as " antherizoids " and " amphi-
gastra." strange interpretations of the functions of wrongly
described structures, and some of the worst drawings in
a badly-illustrated book.

However, it is just possible that some amateur naturalists
into whose hands this book may fall will find in it something
to stimulate curiosity concerning the much-neglected Liver-
worts, and to impel them to obtain a more reliable guide to
the study of these plants. For the structure and development
of these plants, it is quite evident that we have as yet no
" popular '■ work that can be recommended to the general
reader, though the botanical student will find practically all
he requires in the works of Campbell and Goebel. It is only
fair to mention that Sir E. Fry gives the names of these works
in the last few pages of his little book. .\s little books of this
kind appear to find a sale, we must admit that with all their
faults they may serve a useful purpose.

(21 Mr. Russell's more comprehensive and ambitious work
has quickly passed into a second edition — a fact which testi-
fies rather to the growth of interest in the Mosses and Liver-
worts than to the merits of this particular book. Certainly
this book will aid the beginner to recognise some of the
commoner British species belonging to these groups, though
the author is obviously uuich less familiar with the Liverworts
than with the Mosses. The book is written in a bright and
interesting style, and the author has wisely refrained from
nmch generalisation and discussion on the morphology,
biology, and classification of these plants. Some of the
illustrations are fairly good, but perhaps the best feature of
the book is the chapter of nearly forty pages on the
collection and preservation (including microscopic mounting)
of specimens.

It may appear somewhat harsh to criticise adversely such
books as Sir E. Fry's and Mr. Russell's, since the avowed
object of the author in each case is merely that of arousing
interest in the plants dealt with and pointing the way to more
advanced and systematic study with the aid of larger works.
If the writers of such books would simpK' confine themsehes
to what they are more or less familiar with — rthe general
characters of the commoner species and their habitats, and
methods of collection and preservation — they would entirely
disarm the criticism which, as it is, they provoke by their ill-
informed and totally unnecessary treatment of the scientific
aspects of the subject. If it is considered necessary to touch
upon these topics, it would be much better to give a series of

^02

KNOWLEDGE.

May, 1911.

(juotations from i-eliable books or papers by scientific writers,
or to invite the coiiperation of a scientific naturalist — or at the
very least to submit their manuscript to an expert for revision.
If either of these courses were adopted, somethinj? might be
done to remeSy the slipshod and inaccurate character of
■' popular" books on Botany and Nature Stud\-.

F.C.

CHEMISTRY,

nactcriologiciil and Ensyiiic Cliciiiistry. — By G.J. Fowi.hr,
D,Sc,, F,I,C, 328 pa.!,'es. J2 illustrations, 75-in. < D-in.

(Edward .Arnold. Price 7 6 net.)

Just as the border line between physics .ind cheniistrv
is rapidly breaking down, so, too, in another direction, is
the division that formerly separated chemistry from biology.
Not only has chemistry made clear many previously obscure
physiological processes, but the principles of the new branch
of the science have found technical applications in many
directions. In fact, so important has biological chemistry
now become that the Institute of Chemistry has established a
special examination in the subject, and one of the objects with
which this book was written was to provide a general
introduction to the numerous books which must be studied
by those reading for this examin,ation. For this purpose the
book will be found admirably suited, and, in addition to this,
it is so simply and clearly written that it may be read with
interest by the general reader.

After a good description of the characteristics of chemical
action in li\'ing bodies, and the methods used in bacterio-
logical work, it gives a clear outline of the principles of
organic chemistry : and this is followed by an account of the
specific actions of various en^ymes and bacteria, together with
a description of their application in various industrial pro-
cesses, such as the fermentation of indigo, the purification of
sewage, and in agriculture.

It is to be regretted that while in some of these descrip-
tions the author has availed himself of the scientific assistance
of specialists in different branches, he has neglected to do so
in others, the result being that his accounts of technical
processes are of very unequal value. Thus, some of his
statements about the manufacture of vinegar are inaccurate,
and others only partially true, while the process described
as that in general use is one that has been obsolete for very
many years.

It is stated (page 149) that, according to Pasteur, the oxida-
tion of the completed acetic acid to carbon dioxide and water
is effected by other organisms, such as yeasts, and so on. Now, it
IS a fact that the acetic bacteria themselves oxidise the acetic
acid as soon as they have exhausted the alcohol ; and a refer-
ence to the original treatise of Pasteur shows that he wrote
the very opposite to what is stated by the author, viz. — "' When
vinegar loses its acidity this is solely due to a slow combustion
process which is brought about by Mycodcnna aceti."

.Another inaccuracy occurs in the description of the fat-
splitting enzymes, where it is stated that mutton and beef fats
are compounds of glycerine and stearic acid. Both of these
substances are undoubtedly present in the fats, but the
commercial beef " stearine " is far from agreeing in composi-
tion with the chemical compound " stearin," for it contains
palmitic, oleic and other fatty acids — in some cases in greater
proportion than stearic acid.

But these errors are trifling in comparison with the general
excellence of the book, and the author may be congratulated
upon having maintained interest in his subject without sacri-
fice of its scientific value. ,, , ,,

L . A. M .

Alchemy : Ancient iiiul Modern. — By H. Stanley

Redgrove, B.Sc. (Londl. 141 pages. 16 illustrations.

8'(-in. X 5J-in.

(William Rider & Son. Price 4 6 net. I

Most of the modern books upon Alchemy suft'er from the
drawback of having been written without due appreciation of

the scientific basis underlying many of the old theories, or, on
the other hand, with an exaggerated importance attached to
what was obviously meant as mystical symbolism.

The author of the present book, however, is not only a man
of scientific attainments, but is, as his writing shows, strongly
in sympathy with the mystical trend of the alchemists, and the
result is an exceedingly interesting study of their doctrines.

In no other book with which we are acquainted is the
striking manner in which modern chemical thought tends to
approximate the philosophical views of the alchemist so clearly
brought out. .As the author show^s, the alchemists first formed
their theories, and then tried to find for them experimental
support, whereas in modern chemistry experimental investiga-
tion has gradually led to the formulation of theories, which, on
the physical side, are little distinguishable from those of
alchemy. Thus the notion of one primordial form of matter,
upon which was based the alchemists' hopes of transforming
baser metals into gold, has been rendered more than probable
by recent researches in radio-activity. In the earlier part of
the book, a good outline is given of the views of the alchemists
upon matter and their mystical application to the moral world,
and this is followed by brief historical sketches of the leading
alchemists, which are well illustrated by reproductions of old
engravings. It was perhaps ine\ itable, that this biographical
part of the book should lack the interest of the philosophical
portion. The last chapter, in which are contrasted the
ancient and modern \iews upon the transformation of the
elements, is particularly interesting.

The author's general attitude towards the (juestion of the
transformation of metals into gold in the past, is that of
the agnostic, but most readers will be inclined to think that
his agnosticism leans to the side of credulit\- in attaching
much weight to the testimonv of Helvetius.

C. A. M.

PHYSICS.

TIic Cyniscope. — By V. E.
24 illustrations.

Johnson. M..A. 52 pages.
7f-in. X 5-in.

(F. & F. Spon. Price 1 6 net.)

The book is an experimental guide to the interesting
phenomena connected w-ith gyroscopes. It gives instruction
how to make gyroscopes and experiment on them to the best
advantage, in order to show their properties. It leads up to
the construction of a mono-rail car, balanced by one or two
gyroscopes. The author has left theory alone, wisely in a
short book of this kind. But those who wish to know some-
thing of the phenomena connected with rotating masses, will
do well to execute some of the experiments described; while
others no doubt would be much interested by merely carrying
out the experiments as a pastime. -An explanation on page 4i
would be improved by substituting " and " for " in the latter " ;
as it stands the explanation appears incorrect. a p p

.4/( lilenientary Text-book of Physics. General Physics. —

B\- K. W. Stewart, D,Sc, 414 pages. 187 illustrations,

7.5-in. X 5-in.

(Charles Gritfin & Co. Price 4 6 net.)

Dr. Stewart's text-books are the essence of clearness and
lucidity of explanation. This is the first volume of the series
of Physical Text-books, and deals with physical measurements,
dynamics, statics, hydrostatics and the properties of matter.
The text-book contains just the necessary amount of detail
to give the student a thorough grounding in the subject.
Chapters as, for example, that on the balance, or that on the
determination of density, are exceptionally clear on subjects
that many elementary text-books skimp over.

The general arrangement of the book is very excellent.
The student indulges in units and measurements of the
fundamental units till Chapter V., then velocity, acceleration,
and circular motion are dealt with. It is pleasing to find the
latter subject treated in its proper place and with due regard to
its practical importance. Succeeding chapters deal with force,
work and energy in a very clear manner. Then comes statics,

M\v I'in.

KXOWLEDGl-:

203

with a cliapter on the balance, followed by hydrostatics,
properties of matter, determination of densities, and finally the
main properties of matter in the jjascons state. The book ends
with a valuable np-to-date chapter on pnmps. A f F

I'liysicdl MLUisiirciiiciifs. — B\- A.W. Dvvv .and .\. W. K\vi-:i.i .
25S pa;;es. 7iS illnstrations. .Sl-in. X 5'-in.

IJ. S.S; A. Chnrchill. Price 7 6 net. I

The bool< will be a great help alike to those taught and to
the teacher. In the first case the book is not too long, not too
minute in detail, but the descriptions are concise and to the
point. In the second case the book covers a fairly wide field,
so that it aids the teacher in selecting e.xperimental studies for
any particular class of students, .\nother valuable feature is
its numerous references both to practical treatises such as
Kohlrausch's " Physical Measurements." and also to smaller
class text books.

In the introduction, which .gives general advice as to the
taking of observations, their possible and probable errors, and
the plotting of curves, occurs this sentence: — '' Much time in
the laboratory will be wasted unless some preparation be made
before coming to the laboratory .... this may usually
be done at home in a few minutes, whereas it might require an
hour or more in a labor.itorx- where a number of people are
moving around." This is very true. The man who is
researching would not come to the laboratory and spend half-
au-hour picking up the thread of the previous day's work ; he
comes generally' with a fi.xed intention of trying some particular
experiment which he has carefully planned out. So, too, it
should not be that the student should have to spend much
time reading through the directions for carrying out an experi-
ment during his attendance at the laboratory, only to carry
them out like a cook following a recipe. A little previous
study, a preliminary lecture, and a little personal instruction,
is more desirable ; then the experiments will be carried out
intelligently, and without the necessity of elaborate descriptions
of the mode of procedure.

One would like to have seen a more complete account of the
use of a cathetometer. of specific gravity measurements, and of

thermometer corrections : points of which it is most desirable

that a student who subsequently r(S<arches should have a

practical knowledge. , _ „

A. C . K.

ORNITHOLOGY.

Britain's ISii-ils ttiid tlicir W'sts. By A. Lan'usboroi'gh

Thomson-, with an introduction by J. Arthtr Thomson.

340 pages. 132 plates. lOi-in. X 7' iii.

iW. & R. Chambers. Limited. Price 21 ■ net.)

This book, which is illustrated by Mr. Rankine's coloured
drawings, is a careful compilation of the most important and
interesting details with regard to British-breeding birds, in
which the writer has incorporated unpublished records of his
own and of many competent observers whom he counts amongst
his friends. The text is written in language which is easily
understood, and the system and nomenclature adopted are
those followed in the second edition of Howard Saunders'
" Manual of British Birds."

.As regards the colouration of the birds and the eggs, the
plates will prove very useful. In some of them. hovve\er. one
particular flower, which is characteristic presumably of the
habitat of the bird, has been dragged into the picture and
emphasised in such a way that it detracts somewh.it from the
intention of the drawing.

Professor Arthur Thomson contributes an introduction in
which he treats birds from a biological point of view,
emphasising the interest to be gained from their study, but
saying that while the living bird attracts most minds, and
provides a man with enough to kee|) him busy all his life, half
the wonder will be missed if there is not also some analysis of
structure. He touches on the behaviour, migration, .and
development and evolution, as well as the practical importance
of birds, and concludes with a plea for the efforts which are
beiu,g made towards bird protection, partly by legislation,
partly by the education of public opinion {e.g., as regards the
use of feathers in decoration, other than those from domesti-
cated birds, like the ostrich, and from birds shot for food)
and partly by the establishment of bird sanctuaries, some of
which have already been attended with remarkable success;
for when a bird has been exterminated, its loss is irreparable.

W.M.W.

NOTICES.

A Ni:\V ITKLD GLASS.— We liave received from Messrs.
C. P. Goerz's Optical Works. Limited, a list of their Trieder
Binoculars, among which a new introduction, the- " Neo-
Trieder," calls for attention, as it has several special features,
among which are its excellent definition, its increased field of
view, which means, of course, that more of the field looked at
is seen, while there is enhanced stereoscopic effect and greater
illuminatiou and brightness of the picture consetpient upon the
emplo\-ment of larger object glasses.

SCILXTIITC PHOTOGRAPHIC PLATES.— There nmst
be many who are seeking for photographic plates for various
scientific purposes, and to these we commend the descriptive
list of those issued by Messrs. Wratten and Wainwright. of
Croydon. A great deal of useful information is incorporated,
and reference is given to special booklet which this firm has
prepared, dealing- with particular scientific work.

A CINEMATOGRAPHIC HANU-CAMERA. — The
.Aeroscope, of which details have reached us is practically
a hand-camera loaded with four hundred and fifty feet of film
and worked by means of a small air engine. It is brought out
by the .Aeroscope Company, IS. Charing Cross Road. W.C.

PRESERVATION OF THE EVE-SIGHT.— The receipt
of a siuall booklet entitled " Eye-Sight Preserved." containing
many useful hints, reminds us that Mr. Aitchison, who is
responsible for it, is always ready to test eye-sight and give
ad\ ice without charging any fee.

NEW .\PP.\ R.VTl'S. — .Among the new instruments which
Messrs. Zeiss have recently put upon the market are telescopic
spectacles which ha\e been introduced for the benefit of
per.sons suffering from extreme myopia. .Another is the
cardioid ultra-microscope, devised by Ilr. Siedentopf. which is
adapted for the examination of colloid solutions, diluted
precipitates, and the observation of micro-chemical and photo-
chemical reactions. We may mention also the new oral
illuminator for the use of dental surgeons and the new method
of illuminating operating theatres in hospitals with a search-
light and distributing mirrors.

ASTRONOMICAL LECTURE.— Mr. Frank C. Dennett
informs us that he still has a few dates vacant for the
delivery of his lecture on " The Sun, its Structure and
Influence." illustrated by an unique set of lantern slides. Mr.
Dennett's address is 6, Eleanor Road. Hackney, N.

THE BRITISH ASSOCIATION.— A preliminary pro-
gramme has been issued for this year's meeting of the
British Association, which, as .already announced, is to take
place at Portsmouth, on .August 30th and following days.

The opening meeting will be held in the Town Hall
on Wednesday evening, .August 30th. when Sir William
Ramsav. K.C.B.. will assume the presidency and deliver his
inaugural address. In the same hall the first evening
discourse will be delivered on Friday evening. September 1st,
by Dr. Leonard Hill, on "The Physiology of Submarine
Work," and the second, on Monday evening, September 4th.
bv Professor A. C. Seward, on " Links with the past in the
P'lant World."

A BIRD'S-EYE VIEW OF THE HISTORY OF ASTRONOMY

W". ALI-Ri;i) I'AKK.

toK it is in\' o])iiiion that the occasions h\' whicli
men liave acquired a knowledge of celestial
phenomena are no less admirable than the discoveries
themselves." Thus wrote Kepler in niemi)ral)le
words at the beginning of the seventeenth centurw
and few will deny that the history of the oldest and
grandest of the sciences possesses a fascination far
transcending that of many another record of human
acti\ity. In no other sphere of knowledge is the
gradual unfolding of human genius so palpahh'
shown as in this slow endeavour throughout the
centuries to unravel the m\steries of the stars, for
the movement of the mind has been constantK'
onward, and the problems of astronomv ha\e e\er
called its highest energies into requisition.

To chronicle, as conciseh' as mav be, the salient
features in the more modern aspect of this upward

struggle, is the object of the folk

Ta

which purports to present in its \ertical columns a

chronometrical. and in its horizontal columns a

contemporar\- miniature histor\' of astronom\-.

embracin

instrumental details of an\

the chief biographical, theoretical, and
•en period. In order
to bring the whole within reasonable dimensions the
vertical spaces have been arranged in periods of
fifty years, beginning with A.D. 1500. the ejioch
immediately succeeding the Re\i\al of Science in
Europe, thus the various landmarks in the evolution
of modern astronomy appear in close perspective,
showing, in a more graphic manner than is otherwise
jjossible. how completeh' each stage in the progress
of the science has depended on those that preceded,
besides affording a comprehensive mental picture
of this later development as a whole. The method
adopted not only imparts a sense of proportion to
the conception of history which can never be gained
from a mere perusal of abstract dates or a studv of
isolated periods, but also jjermits of the sejiarate
study of the contained matter in a specific way, for
the descending columns give a compressed histor\- of
an\- particular siihjecf. while the horizontal columns
treat of any particular />t7/o(/.

Before, howe\er. entering upon a detailed stud\-
of the Table itself, it w ill be well to premise, in as
brief a manner as possible, an e[)itomized account
of the leading discoveries which were made during
the whole of the pre-Copernican period.
PRIMITIVE .ASTRONOMY.

.Astronomy was cultivated from the earliest times in Egvi'T,
India, and China. The path of the sun and moon amongst
the stars forming the Zodiac and the primary divisions of
the year and month were determined, the motions of the five
planets, Mercury. Venus, Mars, Jupiter, and Saturn
studied, and the Obliquity of the Ecliptic measured by
the nations of antiquity, the most systematic astronomical
observations being those of

THE CH.ALDEANS
who map out the Constellations about 2000 B.C., and who
discover that the Phenomena of Eclipses repeat themselves
in the Saros Period, or cycle of eighteen years. The next
great advance is made by

TH1-: GRICEKS.

B.C. 635 Thalks of Mii.i;tus holds the earth to be a sphere,
and predicts a solar eclipse. (The Gnomon is in
use, and Sundials are constructed.)

., 5S2 Pythagoras, according to his disciple Phii.oi.aus
(B.C. 4001, speculates upon the motion of the
earth.

.. 40') EUDOXUS OF Cnidus expressesthe planetary motions
by the aid of geometry, and sets up the hypothesis
of Moving Spheres, afterwards extended by
Callippus (B.C. 3301.

.. 395 Hkraclidfs OF Pontus is the first to teach the
doctrine of the Earth's Diurnal Rotation.

., 300 Aris tillus and TniocHARis deteruiine the relative
positions of the principal stars of the Zodiac, thus
preparing the way for Hipparchus.

.. 2S0 .Aristarchus OF Samos is the first to propound
the Heliocentric System, lEmployinent of the
.Armillary Sphere.)

.. 2.50 .Al'ol.l.ONlus OF Pkrca devises the system of
Eccentrics and Epicycles.
IfiO Hii'i'ARCHUS. the greatest astronomer of antiquity,
establishes the science on a firm footing by his
catalogue of 1,080 stars, and his discovery of the
Precession of the Eqnino.xes, as well as by his
precise observational methods ensuring accurate
results. (Employment of the Astrolabe}.
.\.I). 130 Ptolemy of Alexandria elaborates in his
" .Almagest " the Epicycles and Deferents of
his predecessors, thus discarding the juster helio-
centric views of .Aristarchns. The Ptolemaic.
or Geocentric. System is doiniuant for fourteen
centuries.

.After this time the .Alexandrian school of
astronomy declines until after the Moham-
medan Conquest in 642. the next advances
being made by

TH1-: AKABS.

iS13 -Almamon founds a school of astronomy at B(r;i;(/(;(/.
and has Ptolemy's ".Alma'^est " translated into
Arabic.

., cS50 .Alba tegnius. the most celebrated astronomer of
the .Arabs, makes accurate observations, and
compiles valuable .Astronomical Tables.

.. 903 .Al-Sufi revises the .Alexandrian list of stars.

.. 1000 .Abui. Wefa discovers the Moon's Variation.

.. 1433 L'lugh Begh establishes a well-equipped Observa-
tory at Samarcand, and compiles a \ahiable
Star Catalogue.

-After this time Eastern astronomy comes to an
end, but Western Europe continues the cultivation
of the science introduced liy the .Arabs into Spain,
the first advances being made b\-

THI-: MOORS.

., 103S .Alhazen discovers the Laxc of Refraction.
.. lOSO .Arzachel. of Toledo, publishes his Toletan
Tables, and repeats the observations of .Albategnius

with greater accuracy.
., 1230 The .Arabic version of Ptolemx's ".Almagest " is

translated into Latin, and about
.. 1270 .A(j()Nso X. of Castile produces at Toledo the

.Alphonsine Tables, compiled by the best

mathematicians of the Moorish universities.

The impulse thus given to a.stronomy by the two latter
events draws the attention of Western learning to the science,
and John HfJi.vwooD's (Sacrobosco) publication of a
Treatise on the Sphere about 1230, and Nicolaus von
Cusa's speculations on the Planetary System about 1440.
prepare the way for the advent of CoPERNICUS.

204

Knowledge, VOLUME XXKIV iJ9ll).

1 ,1 fiue pa^e 204.

CHRONOMETRICAL CHART OF THE DE^i

Period.

A.D.

1500

Time of—
Heno- VIII.
Edward VI.

1550.

(Mary,
Elizabeth.)

1600.

'James 1.
Charles I.
Commonwealth.)

1650.

(Charles II.
James II.
William III.
and Mary.)

1700.

I.Anne,
George 1.
George 1 1. 1

1750.

'George 111.)

1800.

(George I\'.
William I\'.
Victoria.)

1850.

(Victoria.

1900.

'Victoria,
Edward VII.
George V.)

BlOGR.^PHIC.A.L.

Copernicus. 1473-1543

(Works in Polish Prussia).
TvcHO Brahe, 1546-1601

(Denmark and Bohemia).

Galileo. 1564-1642 (Italy).
Kepler, 1571-1630

(Bohemia and Germany)
ScHEiNEK, 1575-1650 (Germany).

Hevelius. 1611-16SS (Germany).
HORROX. 1619-1641 (England).
HuYGENS, 1629-1695 (Holland).
Newton, 1642-1727 (England).
Flamsteed, 1646-1719 (England).

Halley, 1656-1741 (England).
Bradley, 1693-1762 (England!

Wm. Herschel. 1738-1822

(England).
Laplace, 1749-1827 (France).

Bessel, 1784-1846 (Germany).
Frauenhofer. 1787-1826 (Germany).
JNO. Herschel, 1792-1871

(England and S. .Africa/.

Theoretical.

Le Verrier, 1811-1877 (France).
Adams, 1819-1892 (England).
Schiaparelli, 1835-1910 (Italy).
Secchi, 1S1S-187S (Italy).
HuGGlN'S, 1824-1910 (Engl.uull.
Janssen, 1824-1907 (France).
LocKYER. 1836- (England).

VOGEL, 1842-1907 (Germany).
E.G. Pickering, 1846- (America).

Gill, 1843- (England and S. .-Xfrica)

Young, 1834-1908 (America).
Campbell, 1852- (.America).

Hale, 1868- (.America).

The Geocentric Syste.m of Ptolciiiy. dominant for fourteen centuries, is brought to
renewed prominence by Piirbach (d. 1461) and Rcgioinontanns )d. 1476). but the
Heliocentric System is definitely revived by Copernicus in 1543.

Tycho, by collecting a vast mass of valuable observations, prepares the way for the
theories of Kepler, who introduces the Dynamic Conception into A.stronomy by
his Three Laws of the planetary motions, which form the connecting link between
the theories of Copernicus and the discoveries of Neictoii.

Galileo, by his telescopic discovery in 1610 of Jupiter's Satellites and the Phases
of Venus, firmly estabhshes the Copernican doctrine, and lays th(! foundation of
Observ.ational Astronomy.

Scheiner, from the observation of Sunspots, discovered in 1610 by Fabricius and
Galileo, determines the Sun's rotation. Horrox predicts on dynamical principles,
and is the first to observe (with Crabtree) a Transit of Venus in 1639.

Riccioli. Hevelius and GriinnUli lay the foundation of SELENOGRAPin by constructing

lun.ar charts.
Hnygeiis discovers the true nature of Saturn's King in 1659.
Newton, by the publication of the " Principia" in 1687, establislies the L'miication

OF Celestial and Terrestrial Science, and shows Kepler's Laics to proceed

from the action of Gravitation.
Flamsteed, whose lunar observations aid Newton's calculations, forms the First

Modern Star Catalogue.

Halley predicts on Newtonian Principles the Return of the Comet of 1682, makes
the first determination of Stellar proper Motion, and the first Southern Star '
Catalogue.

Bradley discovers the Aberration of Light and the Nutation of the Earth's
-Axis, thus laying the foundation of accurate stellar astronomy.

Wm. Herschel. by his discover)' of Binary Stellar Systems, shows Newton's
Laws to extend tln'oughout the universe. He discovers Ukanus in 1781. and by
his telescopic researches becomes the pioneer of Descriptive Astronomy.

Laplace summarizes Astronomical Mathematics in his "Mecanique Celeste," 1799, and
publishes the Nebular Hypothesis, 1796.

Bessel first Measures the Distance of a Star by determining the Parallax of
Si.xty-one Cygiii, and furthers accurate Astronomy by his Star Catalogue, 1818,
founded on Bradley's observations. Jno- Herschel extends his father's Survey
OF THE Heavens to the S. Hemisphere. .Adams and Le Verrier give to
gravitational .-Vstronomy its crowning distinction by the Theoretical Discovery
OF Neptune in 1846.

Draper, Bond, Dc la Rue and Rutherford U840-1864) are pioneers in Celesti.\L
Photography.

The Science of Astro-Physics is established on the interpretation b\- Knxlilioff of the
Frauenhofer-lines in the Solar Spectrum, 1859. Secchi forms the first
classification of Stellar Spectra in 1863. Huggins inaugurates Spectroscopic
Photography in 1863 and discovers CiASEOus Nebulae in 1864.

Janssen, Lockyer. Young, Hale and Deslaudres advance Solar Physics.

Schiaparelli demonstrates the Connection between Comets and Meteors, 1866, and
discovers the Martian "Canals," 1877. Vogel publishes the First Spectroscopic
Star Catalogue in 1883. Gill and Moucliez inaugurate the International
Photographic Chart of the Heavens in 1887. Pickering, Vogel and Campbell
demonstrate Spectroscopicallv the existence of Binary Stellar Systems.

Vogel at Potsdam. Lockyer at London, and Hale at Mount Wilson, affiliate the
work of the .Astronomical Observatory with that of the Chemical Laboratory in their
Study of the Physical Elements of Stellar Evolution.

VELOPMENT OF ASTRONOMY.

Bv \\'. ALFKKl) PARR

Instrumental.

The instruments known to the Ancients ic.g.. The Gnomon. .\rmii;.larv Sphere.

.■\STROLABE, QUADRANT and SextaN'T) continue in use.
Bernard Walther Id. 1504) introduces the use of Clocks in astronomical observations.

Tycho equips his Obserwatory L'kaniborg with greatly-enlarged and accurately-
divided Quadrants and Sextants, and invents the method of sub-di\iding the
degrees on the arc of an instrument by transversals.

Hans Lippcrslicy invents the Refracting Telescope in 1608. and Gir/)7c'o, construct-
ing one in 1609 for himself, magnifying thirty-two times, applies the instrument to
Astronomv, while Kepler improves it in theory.

Heveliiis is the last to make observations without Telescopic Sights, but Gascoigitc
invents the t'lLAR Micrometer about 1640, and Picard definitely inaugurates the
adoption of the Telescope in Conjunction with the Quadrant.

Htiygeiis adapts the Pendulum to Astronomical Clocks in 1656. and invents the
Compound Eyepiece, while both he and Hevelius improve definition by employing
Tubeless ("Aerial") Refractors over one hundred feet long.

Gregory proposes a form of Reflecting Telescope in 1663. but Neicton constructs
the first in 1668.

Rociner invents the Transit Instrument and Eouatorial, about 1690.

Paris Observatory erected 1671 ; Greenwich Observatory, 1675.

Griilii/iii. lUrd. Cory and Raiusdcii
Quadrants about this period.

the most celebrated constructors of Mural

Dolloiid in\ents the Achromatic Refractor, 1758 (suggested by Hull, 17331.
Giiiiiand improves the manufacture of Optical Glass, 1799, enabling Fntiuiiliutcr to

construct Large Refractors.
Win. Herschel advances the construction of Reflectors and erects his Forty-Foot

Telescope in 1789.

Frauenhofer applies the Spectroscope to Astronomy 1815, adapts Clock-work
Motion to refractors 1824, and erects the First Heliometer 1829.

Reiehenbach. Repsold and Troughtun effect Improvements in Instrument-making
early in this century.

Lord Ross erects his great Six-Foot Reflector at Parsonstown, 1845.

The first regular observatories of the S. Hemisphere (Paramatta. 1821 ; Cape. 1829) arc
founded.

The first regular application of Photography to Astronomy is made with the Keu-
Photoheliograph in 1859, but the greatest advances are made after the adoption
by Muggins in 1876, of the Gelatine Dry Plate.

The Astro-Physical Observatories of Potsdam and Meudon, founded 1874 and 1886.

The First Great Refractor {Neicall. twenty-five inches), erected 1870: Lick,
Thirty-Six Inches, 1888; Yerkes, Forty i'nchics, 1897.

The Equatorial Coude erected at Paris, 1882.

Chandler introduces the Almucantar in 1884. ;

Hale devises the Spectroheliograph in 1889.

Turner introduces in 1895 the Coelostat, being a modification of the Siderostat.

The Mount Wilson Solar Observ.atory is established in 1905, and equipped with
horizontal and vertical Coelostat Telescopes, Spectrographs, and Spectro-
heliogkaphs, besides the Chemical and Physical Apparatus of the
Laboratory.

General.

DiuMug this ccnturx- .\stronomy is
still under the Influence of
Greek Tradition, and is at
first solely Geometrical,
treating of the motions of the
heavenlv bodies.

Rise of the Dynamic Conception
in .Astronomy, which after
Galileo is Physical, and
afteriVctc-^o;; Gra\ttational,
treating of the appearance
and nuitual attraction of the
hea\'enly bodies.

Rise of Descriptive Astronomy
and CoSMOGON^■ with Wni.
Ucrsehel and Laplaee.

Rise of Chemical .\stronomy,
after Frauenhofer, treating of
the composition of the heavenlj'
bodies. Astronomy now
gradually widens its sphere
and establishes a UNIFICATION
OF THE Sciences, by extend-
ing terrestrial and planetary
gravitation to stellar systems,
and by showing the essential
identity of cosmical matter
throughout the visible universe.

Knowledofe.

With which is incorporated Hardwickc's Science Gossip, and the Ilkistrated Scientific News.

A Monthly Record of Science.

Conducted bv Wilfred Mark Webb, F.L.S., and E. S. Grew, M..\.

JUNE, 1 'J 11 .

A SCIENTIFIC USE FOR THE STEREOSCOPE.

By A. H. STUAKT, B.Sc, F.R.A.S.

Students whose geometrical studies have been these the latter are undoubtedly the easiest to make

confined to the geometry of two dimensions and the cheapest to produce.

frequently find considerable difficult\- when problems The most elementary knowledge of jierspective is

in three dimensions are presented to them. Ordinary all that is required to make stereosco})ic drawings of

Figure 1.

drawings afford very little help and there remain all the usual problems in solid geoinetry. Figure 1
onlv two methods b\- which assistance may be shows a simple method of drawing a cube in
offered, viz., models and stereoscopic drawings. Of perspective. A figure is. drawn for each eye, the

205

206

KNOWLEDGE.

June, 1911.

vanishing point of the figure for the right eye heing
separated from that of the figure for the left eye by
a distance about etiual to that between the two

figures ma\-

be dt

■d hv the exercise of a ver\-

httle ingenuity.

of a tlieorem in
; this drawing in

Fitu-RH 2.

eves. (In aduUs this is
about J inches, while in
boys of about fifteen
years of age I have found
the average to be about
2-5 inches). For all
practical purposes the
front face of the cube
ma\- be represented by
a perfect square. The
figure also shows the
method of obtaining the
axis of the cube. It
must be remembered
that the geometric
centre of a face is not
necessarily the stereo-
scopic centre. If the
point of intersectitm of Figike 3.

the diagonals is taken,
no mistake can be

made. Similarly, to obtain the middle point of an
edge, draw a line parallel to an edge which is
at right angles to the former through the point of
intersection of the diagonals. This will cut the
edge at the required point. Thus, in Figure 1. .\
and B are the stereoscopic centres of the edges on
which the\- stand.

I have found it convenient to make the drawing
first on a large piece of drawing paper and then
prick through the necessary parts on to the paper
which is to form the finished slide. This not onlv
has the advantage of not showing the construction
lines in the stereoscope, but a large number of figures
of different subjects ma\' often be pricked off the
same drawing. From the cube a vast number of

Figure 2 represents the figure
Euclid. Book XI. By examinin;
the stereoscope the figure stands out in relief in a
most striking manner, and brings home to the mind
of the student the whole meaning of the theorem at
once. The construction of these figures bv the
student is quite an education in itself, in addition to
pro\iding him with figures equal to models in every
wa\'.

Nor does the mathematical student monopolize
the benefits to be derived from the use of the
stereoscope. Figure 3 shows how an ill-formed
crvstal of the octahedral system is derived from
the perfect octahedr(.)n : a matter which is by
no means clear to e\erv student of chemistry.
.\gain. Figure 4 shows the graphical formula of
one of the opticallv active forms of tartaric acid.

I'or ob\ious reasons, if
only one of the figures

figure requires letterinjj
should be lettered.

I ha\e found stereo-
scopic drawings of geo-
metrical solids very
useful in demonstrating
to phvsics students the
theory of stereoscopic
vision. It is perfectly
obvious to them that
the two drawings of
the solid are not alike,
and \et, when their
images are superimposed
b\' the lenses of the
stereoscope, they give
the idea of relief as
plainh" as the solid
itself would do.

COOH

OH

COOH

FiGLKE 4.

DISCS I'OR SOLAR PK( )| IXTION.

We give here three more of the Maps for Solar Projection belonging to the series described in

KnowleDGK" for May. prepared by Mr. John McHarg, which can be used from June 1st tc

une 2/th.

I. Latitude of Centre 0^

207

II. Latitude of Centre + 1 .

208

III. L.ititudf of Centre ±

209

THE AUSTRIAN RESEARCH X'ESSEL ADRL\;'

Bv DR. ALFRED GRADEXW ITZ.

Thi-: research vessel of the Association for the
Advancement of Scientific In^•estigation in the
Adriatic, was built on the D'Este shipvards hv the
Stabilimento Tecnico of Trieste. Though being of
rather modest dimensions, she is most sea-worthv
and. on account of her excellent appointments,
can he considered a model of her kind. The

for covering the rooms located in the hull are only
•70 metres in height, which greatly reduces the
side-pressure of the wind. Ample space is provided
on the plane deck plates, for installing all kinds of
apparatus and doing scientific work. These
structures are fitted sideways with c]uadrangular
skylights and protectiw gratings as well as with

Figure 1. The Laboratory on board the

Adna,

" Adria "' is mainh- intended for the oceanographical
and biological in\estigation of the .\driatic. working
in conjunction with the Austrian Zoological Station
at Trieste.

The chief measurements of the ship are as follows :
Length over all ... ... 20-5 metres.

Maximum width ... ... 4

Height -'-4 „

Draught ... ... ... 1-5 ,,

Capacity ... ... ... 45 tons.

The hull is made of wood, the frame and kuel
being of oak. and the inside and outside planking of
pitch-pine. A skin of copper plate protects the hull
below water against the attack of ship worms.

The various teak wood structures erected on deck

hinged hatch lids. The deck is encircled by an iron
railing, the lower apertures of which are closed b_\-
netting : the upper bars are fitted w ith pulle}s for
lowering oceanographic instruments. The front part
ot the bow (as far as the mast) is set apart for
fishing operations and. therefore, is equipped with the
most warious outfits, comprising a winch for the
rapid hoisting of instruments and nets able to raise
a weight of several hundredweight from the bottom
to the surface of the sea. While being generally-
operated bv electricitx', this winch can as well be
worked hv hand. On its axle are mounted four
drums actuated separately and which are designed
for plain ropes, cables, piano wires and anchor
chains respecti\'el\'. The rope carrying a net or

210

JL-NE, 1911.

KNOWLEDGE.

211

heavv instruments travels from the winch over a
fixed to the mast, thus facihtating the

crane

The Resear

FlGURL, -.
\'essel ■■ Adria '' under weigh.

transi)ort of even the heaviest net bags over a
shallow trouj;h made from water-tight linen and
on which the catch is
searched and sorted.
Close to the mast there
is further a conduit for
discharging sea-water so
that the whole catch can
at an\- moment be im-
mersed in water.

Behind the mast are
arranged the structures
forming the roofs of the
laborator\- located below
deck, the combined saloon
and bedroom, and finallw
the engine room The
rudder, which is actuated
with extreme ease through
a worm engaging directly
with its shaft, is located
astern, ^\■ith a view to utilising as much space as
possible for fishing operations, as well as on account
of the greater simplicity and safety.

Of special importance are the sea-water tanks for
receiving any marine animals and plants caught by
the net. As these manifold organisms should be taken
home alive, the " Adria '" is equipped with what
could fitly be called a complete aquarium, comprising
three wooden cases lined inside with sheet metal and
which contain three to four removable sheet metal
aquarium tanks serving at the same time for the
transport of marine animals from the ship to the
shore. The wooden cases which. A\hen closed, can
be used as benches, are provided w ith conduits for
sea water and compressed air, enabling an\' animals
and algae to be kept in circulating or \entilated
water. In the hind part of the vessel is installed
a large tank likewise containing circulating sea
water and compressed air and which takes up
nearly the whole width of the ship. This is

FiGURH 3.
An Oceano,i;raphical SpeciaHst at work

intended for receiving big fish and marine animals.
The supply of sea-water to the aquarium tanks is
effected during the time the ship engine is at work,
that is, throughout the course of the \'essel, by a pump
coupled to the propeller shaft, while an electrically-
operated centrifugal pump is resorted to during
intervals in its operation. The compnssed air is
generated b\- a compressor connected to the ship
motor which allows air to be compressed in cylindrical
iron vessels to four atmospheres, reduced by a throttle
\alve to one-twentieth of an atmosphere. The com-
pressed air also servesto actuate the whistle of the ship.
The compass, a fresh-wnter tank and an ice tank
are likewise located astern.

On each side of the \'essel is suspended from a
crane a launch four metres in length. These
launches, one of which is equipped with a gasoline
motor of two-and-a-half horse power, are intended
for landing at and exploring such parts of the coast
as are not accessible to the " Adria."

As regards next the arrangements provided below
deck, the copper tank containing the fuel (gasoline,
petroleum or alcohol) is located in the very front

of the fore-ship, being
separated by a fire-proof
metal partition from the
bedroom of the crew.
This tank has a capacity
of about nine hundred
kilogrammes. which
enal)les the \-essel con-
tinually to sail about
fitt\- hours, covering a
distance of about four
hundred and fifty knots.
As the motor is mostly
stopped b\- night, a new-
fill of fuel generally is
required only every five
days.

The bedroom of the
crew also contains anchor
chains, tows, tent co\-ers, nets, and flags. A
special room is provided for photographic work.

The Plankton

Figure 4.
Nets being

hoisted astern.

212

KNOWLEDGE.

June, 1911.

The Laboratory (see Fissure 1). like the adjoining
saloon, is dominated b\- a roof structure and deri\-es
its light parth' from the side-windows of the latter
and partly from four circular hatchways in the ship's
walls. On its longitudinal sides are arranged lockers
•90 metre in height for stowing away instruments,
on the top of which ample room is pro\ided tor
performing all sorts of operations and installing
scientific apparatus. The laboratory further comjirises
a compressed-air conduit w ith six discharges, allow-
ing small aquarium tanks to be thoroughly aerated.
Two additional berths can be made up on the
instrument lockers in cases of emergency. As the
ship engine works with remarkable smoothness.
microscopes of modest magnifying power can very
well be used in a quiet sea. which is the more
advantageous as the plankton of the sea should be
examined while still ali\e. at least for its main
characteristics. The Laboratory is. of course,
equipped with all sorts of oceanographic and other
instruments.

In the middle of the ship, vi/., in the part taken
up on steamers bv the engine and boiler, is located
a spacious, well-aerated and lighted saloon, which
serves as dining as well as bedroom, .\longside its
longitudinal walls are installed four lierths with
chests of drawers and on its transversal walls
four wardrobes, one of wlmh has been converted
into a pantrv. contaiinng an ample suiijih" of
crocker\-.

The engine plant is located in the hind part of
the vessel. The engine is a sevent\-fi\'e horse-
power motor, constructed b\' the W'oh'erine
Works, at Grand Rapids, Michigan, imparting
to the ship a speed of nine knots, which,
thanks to the excellent design of its carburettor,
can be operated at will with gasoline, petroleum,
or alcohol. This motor is of a ver\- substantial

construction and remarkably simple manipu-
lation and superintendence, being started merely by
a pressure on the le\er of the electrical ignition,
in order afterwards to go on working quite
automaticalh', needing inspection only from time to
time. This engine has repeatedly stood severe tests
in a rough sea with excellent results. In order to
afford greater stabilit\- in a gale and heavy seas, the
vessel has been equippe<l with a triangular sail and
a jib.

This engine is coupled to the air compressor
supphing air for aerating the a(]uarium tanks and
operating the ship's whistle. In the same part of the
vessel is located the electric plant which comprises a
two horse-power gasoline motor coupled to a dynamo,
generating electric current at sixty-five volts tension
for operating the w inches and lighting the vessel. It
issupi)lementedbvan accumulator batteryof thirty-six
cells, resorted to in cases of emergency and when the
d\-namo is stopped. Scientific work can thus be con-
tinued even by night, allowing, e.f^.. the air bubbles
from liottles immersed in the sea to be watched with
a \-iew to ascertaining the course of water currents.
The installation of a search-light will likewise be of
much importance for biological and oceanographic
pur[)oses. Finall\-. there is a possibility of ojierating
directh' from the d\'namo or accumulator batter\-.
a sea-water pump for keeping up the water circula-
tion in the aijuarium tanks.

.\djoining the engine room is the shiji's kitchen
wliich. in spite of its (liniiiuiti\-e dimensions, perfectly
suffices for its task. It is equijiped with an
econoniiser sto\'e for coal firing and all necessary
kitchen utensils.

.\[iart from its use as a research vessel the '■.\dria"
is alst) to ser\e for instructional purposes, in
connection with periodical journeys of scientific
disco\er\' for the lienefit of undergraduate students.

SCIENCE .\T TfiE CORONATION KXllIi'.lTlON.

For a third time a science section has been arranged at
the Shepherd's Bnsh Exhibition, and this year the Committee,
of which Sir .Alexander Pedler, F.R.S., is Chairman, lias
bronght together a number of very interesting exhibits. We
hope to deal with some of these in detail, but at the moment
we may point out that a feature of the Astronomical division
is a series of transparencies, while there are collections of
sundials and astrolabes, as well as some remarkable models
sent by Greenwich Observatory. The Meteorological Office
illustrates its useful work and there are some instruments on
view. Anthropology is represented by measuring instruments,
old and new ; by a series of casts of the oldest known skulls ;
and by Dr. Gray's Perseveration apparatus, described by him
in "Knowledge " for December. 1910. It is kept in a small
bureau in the right hand corner I going from Uxbridge Road),
of the first building devoted to science, and visitors may be tested
upon application. Fifty years' work of the Geologists' Associa-
tion is represented by collections made upon the well-known
excursions of the society, and there is a good series of fossils
showing changes in structure of the teeth of Ccratodns. The
fossil eggs of fishes are noteworthy, and the specimens of the
spines of sea urchins which, though alike externally, show
internal structure \\ liich is characteristic of tlie \arions species.

The apparatus employed for investigations on the rusting of
iron is a special exhibit in the Chemical division in which also
coloured compounds, new drugs, and the making of Vanadium
steel are illustrated. Physics is necessarily chiefly represented
by apparatus. The Biological exhibits are not extensive but
call for special attention. The London School of Tropical
Medicine sends a detailed exhibit including a prehistoric skull
showing that trepanning was practised long ago. University
College, Bristol, exhibits some excellent models showing electric
installations in connection with the growing of crops in field
and in greenhouse. The Selborne Society makes a display of
the English nesting boxes recently introduced with much
success. The .Agricultural exhibits illustrate the work of the
Board of .Agriculture in the way of distributing maps, of
fisheries, and the study of plant diseases as well as of
forestry. The Earthcjuake-recording instruments shown have
been of practical \alue in connection with railway work
and the Isalancing of engines. The Royal Geographical
Society sends facsimiles of the maps of celebrated explorers
and one or two relics. Oeeanogr.aphy occupies itself
with subin.u-ino cables, and in this division is shown
a nunilnr of photomicrographs of minute forms of
ni.ninc life, such as were found at very great depths.

CONCERNING DIMENSIONS GENERALEY, AND THE
EFFECTS OF THE FOURTH DIMENSION

IN PARTICUEAR.

r.v A. L. AXXISON.

The word dimension is tlic ,L;encral term used to
indicate extension in space, whilst spare itself is
nothin.i; more than the abstract idea of infinite ex-
tension \n all known directions.

There are said to be three dimensions, namel\-,
those of length, breadth and thickness, and all our
conceptions of shape and size are formed relatively
to one or more of these three, which seem quite
adequate for the expression of our ideas. The exist-
ence of others must, therefore, seem extremeh'
problematical, and if at times a guess is hazarded as
to the fourth dimension, its nature is assumed to be
quite different from that of the other three : so much
so, indeed, that in some instances it is held to consist
of time itself.

Now it is one purpose of this article to show that
from certain facts which we shall proceed to
examine, the existence of an infinite number of
dimensions may justifiably be deduced. It will be
shown that these dimensions are of the same nature
as the three with which we are familiar, and that our
ignorance of their existence is due to some personal
limitation whereby we are unable to form any mental
image of the shape and size of a bodv, beyond that
small portion of it which is bounded b\- a surface
extending onl\- in the first three dimensions, the
others, therefore, seeming to be nothing more than
purely abstract ideas derived from mathematical
expressions.

Notwithstanding this, however, we shall also be
able to show that some of the effects of the fourth
dimension are of such a nature as to be appreciable
in spite of our limitations ; and the latter part of this
article relates to the nature of these effects antl under
what conditions they can be produced.

The basis of our argument depends on the
relation between algebraical equations of two and
three variables and geometrical figures of two and
three dimensions. It is known, for instance, that the
locus of a point moving according to the equation
x'^+y'^^r^> is the circumference of a circle, or in
other words the equation is the " law of the circle "' :
and similarly x'^+y'^+z^ = r'^ is that of the sphere;
but there are an infinite number of equations of this
type, each containing one more variable than the
preceding one ; and arguing by analogy from the
first two, the next one x^+y^+z^+u''^=r'' is the law
of a four-dimensioned figure : x'" + \--|-/'" + u'- + v" = r',

of a five-dimensioned one, and generall}" x" + >'H

(>; terms in all)=r" of an >j dimensioned one, where
rj may be anv number between 2 and c^.

The fact that we are unable to form an\' mental

image of such figures cannot be ascribed to the
equations themselves, which obviously contain no
reason either wh\' they should or should not be
capable of graphical representation. Prima ftjcic,
if some equations can be so treated, the remainder
should equall}- admit of such treatment, and our
inability to accomplish this must obviously be due
to the absence of an\- mental picture that will satisfx'
the requirements of the equations.

Now the pictures that we can conceive consist of
nothing more than the figures formed b\- enclosing a
portion of space, either by a line or lines (plane
figures) or hv a surface or surfaces (solid figures) ;
the line and the surface are the materials with which
we construct these figures. We cannot, however,
construct a four-dimensioned figure of any kind,
although we have the necessary material, namely,
what for want of a better name must be designated
the volume.

The inabilit\' of our imagination in this respect
must be due to some limitation in our powers of
perception, for it is from the impressions of external
objects, as seen by the e\-es, that we form our
mental images of figures, regular or irregular.

Now it will be shown that our eyes cannot
appreciate an\- figure with more than three dimen-
sions. It might be argued from this, that it does not
follow that there are such figures to be seen, but
from an examination which we shall make of the
undoubted fact that all visible bodies b\' which we
are surrounded are at least three-dimensioned, the
existence of these more complex figures can be
inferred.

By the term "body" employed above, is meant
something that has an independent existence and
is, therefore, an object as distinguished from an
attribute.

All bodies, as we shall see, are defined by their
apparent size and shape and are, therefore, figures of
some kind, regular or irregular ; but on the other
hand all figures are not bodies, for every two-
dimensioned figure is onh' found as a bounding
surface of a three-dimensioned one, and by itself
is quite as abstract as colour, taste, and all other
attributes.

So far as we know, however, the three-dimen-
sioned bodies appear to be self-contained and
independent of any higher dimensioned body; they
do not seem to exist merely as the sections of
four-dimensioned figures.

It will be shown that this can be accounted for
by the limitation of our powers of observation, and

ns

214

KNOWLEDGE.

JrxK. l')ll.

that there is no cause \vh\- four and other dimen-
sioned figures should not exist : from this it follows
that the only figures which are not the sections
of higher dimensioned ones must be those possess-
ing an infinite number of dimensions : in other
words, these last mentioned figures are the only ones
that can have "an individual existence.

The first point for us to determine is the
possession bv ever\' visible body of at least three
dimensions : we shall then proceed to shov\- that
the\' must be inferred to possess an infinite number
of such dimensions: and finalh" to examine the
effects produced by certain four-dimensioned figures,
firstly when mo\ing in the direction of the axis of
the fourth dimension and secondlv when expanding
and contracting in the three-dimensions with which
we are familiar.

Now all visible bodies must necessaril\- have
dimension of some kind.

The impressions of things external to our mind
are received and transmitted to it by means of the
senses and their organs : and we must consequenth-
remain utterly ignorant cif anything that does not
appeal to at least one of our senses.

We find that all sense impressions conveved to us
have their origin in objects that jiossess extension in
space. Colour, scent, light, sound, taste, heat and
cold, all are in\"ariabl\' found to proceed from such a
body : and conversely there is no visible bod\- that
has not extension in space, a possession which is
indeed its primar\- attribute, all others such as
colour, taste, and so forth lieing of serondar\-
importance.

When we proceed to consider those things that
ha\e dimension, we find that some onl\- of them
have an independent existence and therefore comph-
with our definition of a body. Others, which are
figures only, and nothing more, do not exist apart
but are only attributes of a bod\'. Thus we find
that a solid such as a cube is an actual object, but a
surface such as the square merelv forms part of the
solid : we do not find one existing alone, absoluteh'
dispossessed of thickness.

The straight line is nothing more than part of the
boundary of a plane figure : and so far is it from
possessing an independent objective existence that it
is even unimaginable : for geometrical purposes we
have to allow it some degree of thickness, although
we thereb}' convert it into a plane surface.

The solid, then, is a bod\-, because in addition to
its length and breadth it possesses thickness : whilst
lines, having merelv one dimension, can only serve
for the construction of a plane figure, and the plane
figure by itself, having only two dimensions, is no
more an object than the line : it is an abstraction that
serves as an attribute of a three-dimensioned hod\".

Now all visible bodies are found to have three
dimensions; there is no l)ody, either artificial or
natural, that has not length, breadth and thickness.
Our next step is to enquire wh\- this is so. On the
one hand it ma\' be because there are no one or two

dimensioned bodies; and, on the other, because we
ourselves, on account of some inherent limitations in
our power of sight, are unable to perceive them.
This last hypothesis, however, is obviouslv untrue,
for not only do we see that part of a bod\- which
possesses only length and breadth, that is to say its
surface, but that is all we can see.

It is. therefore, obvious that we could detect the
presence of any plane surface, such as a square, if
such a figure ever had an independent existence.

Let us imagine a square of this nature to come
within the sphere of our observation. What charac-
teristic impression would it produce on us?

Well, suppose that we first of all observed it when
looking in a direction at right angles to the plane in
which it lies: it would then appear as a square.
Now let us mo\'e as though we were about to pass
b\- its upstanding edge on one side, in order to attain
a position at its rear. With our eyes directed on it
the square would apparently' diminish in width, but
not in height, becoming narrower and narrower,
until nothing but a small strip remained; and even
this would finally disappear when one reached the
edge of the figure: the square would be completeh'
invisible, since it has no thickness. Then, as we
passed be\-ond its edge and towards the rear, the
surface would reappear, and increase in apparent
width, until it regained its full size and shape.

Now such a phenomenon as this has never been
seen, and it therefore follows that there are no
bodies with onl\' two dimensions : and further that
there cannot be an\' with simpK' one. for if there
were, a two-duuensioned bod\' could be constructed
therefrom.

In the course n\ the foregoing arguments it was
remarked that we could only percei\e the surface of
a bodv : and that, therefore, if we looked at a plane
surface, we only observed its length and breadth,
the thickness remaining unperceived and unde-
termined. Our next point of inquiry will endeavour
to explain why we only see the plane, and how it
is that we can ascertain the existence of the third
dimension.

The e\'e is. of course, the organ of sight ; it
comprises a lens and a screen called the retina.
This screen consists of a surface, and is analogous
to the sheet on which magic lantern pictures are
displa\'ed, the eye lens being equivalent to the
compound lens of the lantern.

Now. it is impossible to produce anything but a
flat picture on the lantern sheet ; the image of a
globe, for instance, cannot be projected so as to
possess length, breadth, and thickness ; the length
and breadth can be displayed, because the screen
itself is a plane surface, but the thickness can only
be simulated b\' a skilful distribution of light and
shade.

Similarh' the image impressed on the retina is
essentialK' two-dimensioned ; and for this reason we
are frequenth" led to mistake a round body for a flat
one ; the moon, for instance, alwa\s appears to be
fiat,

Jl-NK. 1011

KNOWLEDGE.

215

The image produced by the eye being invariably a
plane figure, we should be unable to determine
whether a bodv were two or three dimensioned if
neither \\e nor the body sur\'eyed could move
relativeh- to one another.

As it is we are enabled to survey a sphere, a cube,
a tree, a house, or an\- other object from innumerable
points of view w ithin our three-dimensioned space
and thus to inspect its surface or surfaces and satisf\-
ourseh'es that it is indeed a solid ; our opinion is
formed from the multitudinous images impressed on
the retina of the eye as we move about from point to
point or awail <uirselves of the motion of the body
which serves to displa\- its various parts before our-
selves, the observers.

Now just as we mistake solid figures for plane
ones, so in a like manner when we survey a four,
five or infinitelv dimensioned figure we should
imagine it to be three-dimensioned ; for it would
completely satisfv the investigations we could make,
bv looking at it from all [jossible points of view
within our three-dimensioned space : of course, its
shape as regards the fourth and higher dimensions
would remain inscrutable to us, so that we could not
possibK- foretell their existence or non-existence : Init
thev might be there all the same, for we could
prove nothing to the contrary

Xow proceeding briefl\" to summarise the con-
clusions attained we ma\' state that : —

(1) Algebraical equations of one. two and three
variables can be graphically represented : and certain
of these equations with two or three variables
are the laws of certain plane and solid figures.
In particular x'^ -(- y ■^ = r'^ represents a circle and
\'-{-\'~-{-z^^=r'^ represents a sphere. If in the
last-mentioned equation we put z = o. we obtain the
first equation which can be shown graphicalh' to
represent a section of the sphere.

There are an infinite number of equations in
this series, and it we take the next higlier one
x''^-|-y^ + z"+u''^ = r" and put u = o, we obtain the
equation of the sphere: in other words the sphere
is a section of this four-dimensioned figure : we do
not, however, mean to impK' that it cannot also be
the section of other four-dimensioned figures, since
obviouslv it can be, preciseK' in the same wa\' that a
circle might be the section of a c\linder. cone, or
other solid.

The four-dimensioned figure is the section of a
five-dimensioned one, and this progression is
continued to infinitx', the infinitely dimensioneif
figure being the onlv one that is not a section of a
higher dimensioned figure. In spite, however, of
the necessary existence of these complex figures we
are not acquainted with anv of them from the four-
dimensioned one upwards.

(2) All our ideas of figures cannot be more than
three-dimensioned because of the limitations in our
powers of observation.

(3) There are no one or two-dimensioned bodies :
all bodies appear to be three-dimensioned, and two-
dimensioned figures are onl\- found in realitv as

sections of these bodies. This is in accordance with
the algebraical equations from which it can be
deduced that the straight line is the section of a
circle or other two-dimensioned figure, and the
latter a section of a three-dimensioned figure such as
the sphere.

(4) That the sphere is apparent!}- not a section of
a four-dimensioned figure, but appears to belong to
that highest t}-pe of figure which extends in all
possible dimensions (supposed to be three in
number*, is a fact that is not in accordance with
what we should expect from the algebraical
etiuations : but it can be brought into agreement
therewith by allowing for our undoubted inability
to appreciate more than three dimensions, together
with the certainty that any four or higher
dimensioned figures would appear three-dimensioned
to ourselves.

(5) Paragraphs 3 and 4 explain wh}- all visible
bodies appear to possess three dimensions and
neither more nor less, and since there are no one
or two dimensioned bodies, there is no justifiable
reason wh\' there should be an\' three. foLn\ or
finitely dimensioned ones ; on the other hand, all
bodies must be infinitelv dimensioned, although we,
by reason of our personal limiiations cannot perceive
more than three of these dimensions.

(6l Olniously space itself, the ether and other
bodies, must also be infinitely dimensioned.

Now from any body such as one w liose algebraical
equation is x" + \'-+ . . . (=o terms in alll:=r-, we can
take a section. ol>taining thus a figure whose equation
is x-+y-4- . . . (oo— 1 terms in all)=r-, and then a
section of this, and so on until we obtain the four-
dimensioned figure \-+\-^ + z-+u- = r-, the sphere
x^+y-+z- = r- and the circle x-+y- = r-. Con-
versely, starting with the circle, we can sa\- it is the
section of a sphere, a cone, a cvlinder, or some
other solid figure : and similarh- the sphere is the
section of a four-dimensioned figure which mav
belong to the spherical t\"pe, the conical t\pe, the
cylindrical type, or some other.

Our purpose now is to take the sjihere. cone, and
c}'linder and show how they would appear if we
were onl\- two-dimensioned, and how we could
distinguish one from the other : and then, arguing
bv analogy to show how the four-dimensioned
figures of the spherical, conical, and cylindrical
t\-pes would similarh- appear to us with our three-
dimensioned faculties, and how the effects produced
bv them would be characteristic and distinguishable
from one another.

The simplest way to proceed is to hypothecate
the existence of a two-dimensioned being, one who
can onlv percei\-e length and breadth and is
absoluteh- ignorant of the existence of thickness :
his observations must be confined to w-hat takes
place on a plane surface which, consisting of infinite
length and breadth, will be to him what space
is to us.

The onl\- figures of whose existence he can
possibly be aware must be two-dimensioned ones,

216

KXOWLEDCxE.

Junk. 1911.

and these only if they lie in his plane of observation.
Such figures would be presented when a solid was
intersected by the plane surface. Now we can
imagine a solid to move downwards towards the
surface from above and to pass completel\- through
it. Before and after the passage of the solid, no
part of it would be seen b\- the being, but during the
event, he would observe a series of sections, each
consisting of a plane figure.

Now these sections, of course. W(.)uld be definiteh-
correlated to one another, since one and all belong
to the same bodv. and from their change or
constancy in size and shape, it would be possible for
the being to determine the nature of the solid figure.
Thus from the fact that he saw a circle of unvarying
diameter, he could hvpothecate the existence of a
cylinder : and similarly, if the circle were one that
appeared to increase or decrease in diameter, it could
be ascribed to the existence of a right circular
cone, sphere, or some other solid figure whose cross
section was a circle.

Furthermore, the particular kind of solid could be
deduced, for the\" wciuld each produce a different and
characteristic change in the size of the circle. A
sphere, for instance, would produce a circle at first no
larger than a point, but which would increase
gradually until it became a great circle of the sphere
and then decrease again to a point. A right circular
cone, assuming it to approach apex first, and parallel
with the axis of the third dimension, would also
first produce a circle no larger than a point : this
^\■ould also gradually grow, but it would not subse-
quentJN' decrease like that produced b\- the sphere.
Furthermore, provided that both cone and sphere
moved downwards with uniform velocitw there would
also be this difference — that any point on the circular
section of the cone would mo\-e radialh- outwards
with a uniform velocit\', whilst an\' point on the
similar section of the sphere would move outwards
with variable velocity : and its acceleration w ould be
just as characteristic of the sphere as the uniform
velocity was of the cone. Any other figure would
produce a characteristic acceleration.

Now just as the sphere and cone moving down-
wards along the axis of the third dimension pre-
sented the phenomenon of a plane: figure (the circle)
growing equally in the two dimensions of the plane,
so would the spherical figure of tlie fourth dimension
(equation x''^+y-+z'^+u"=r^), and the cone-like figure
of the same degree, each moving downwards
along the axis of the fourth dimension with a uniform
velocity, present to us the phenomenon of a solid
figure (the sphere) growing equally in the three
dimensions of space : in the first instance with
characteristic acceleration, and in the second with
uniform velocity; and just as it is possible to
account for any imaginable change in the size and
shape of a plane figure b_\' the hypothesis that it
forms part of a solid figure moving downwards along
the axis of the third dimension, so similarh- is it
possible to explain any increase or decrease in the
length, breadth and thickness of a solid figure h\' the

hvpothesis that it forms part of a four-dimensioned
figure moving downwards along the axis of the
fourth dimension.

It is likewise [)ossible to explain the propagation
of ether and other vibrations, originating from a
point, in the same way ; for we know that such
vibrations, starting from the point, advance at a
uniform rate in all directions, so that the wave front
of each \'ihration consists of a sphere constantl}-
growing outwards at a uniform velocitv, the precise
phenomena that would be produced bv a downward
movement along the fourth dimension of some four-
dimensioned cone-like figure.

There is this objection, however, to such a theor\-,
that if ether is infinitely dimensioned, there is no
reason wh\- the \'ihrations should not extend equally
in all of them, so that the shape of each wave front
would be represented by the formula x-+y^+ . . . (oo
terms in all) = r"-^, and it is impossible to presuppose
this figure to be the section of any other figure or
for it to be caused bv motion along a dimension not
included in the equation, for all the dimensions are
included therein.

There is. however, another point of view from
which to regard the propagation of these vibrations.

It is known that before the discharge of an electric
spark, the ether in the neighbourhood is in a state of
tension; it might be regarded as being attracted
towards the point where the electrical charge is
collected.

Now suppose for the moment that we regard the
ether as only three-dimensioned, and ourselves to be
only capable of appreciating two dimensions; and let
the charged point lie in the plane of our obser\-ation.
The ether will Ix' attracted to the point from all
directions, and wc may imagine the space about the
point divided up int(.) an infinite number of con-
tiguous cones of ether, all with their apices at the
charged point; in the normal state of affairs, with
no electrical charge in the neighbourhood, these
cones would become cylindrical tubes, and the conical
shajje is therefore always an unstable one, tending to
re\ert to the cvlindrical form as soon as the point is
discharged. It is obvious that in undergoing this
change of form on the discharge taking jjlace, all we
should appreciate would be an ether disturbance
travelling outwards from the point in the form of an
e\er-increasing circle; for we could only observe the
lateral expansion of the cone whose axis was perpen-
dicular to our plane of observation; all the other cones
in their expansion would immediately extend above
or below our plane, and thus become unobservable.

Now similarly, since we observe an electrical dis-
turbance to travel outwards in an ever-growing
sphere, we may imagine the ether in the neighbour-
hood of the charged point to be composed of a series
of four-dimensioned, cone-like figures ; or assuming
that the disturbance travels outwards in as many
dimensions as possible, to be composed of infinitel\'
dimensioned cone-like figures, each of which has for
cross section a figure whose equation is x-+y-+ . . .
(oo — 1 terms in all)=r-,

AN INEXPENSIVE APPARATUS FOR THE SYSTEMATIC
SEPARATION OF SEDIMENTS BY MEANS OF HEA\'Y

SOLUTIONS.

Hv CHARLES R. MAPP. F.R.M.S.

Figure 1.

Heavy solutions, such as those of Klein, Sonstadt,
Rohrbach, or Braun, offer a read\- and fairly satis-
factory means of separating sediments, sands, and

comminuted rocks into
groups varying in specific
gravity, and thus materially
assist the laboratory ex-
amination of such material
for the identification and
estimation of the com-
ponent minerals either
qualitati\el\- or quantita-
tivelv. In using them,
however, numerous small
difficulties present them-
selves, and the process
becomes both lengthy and
tedious unless carried out
in definite steps, which, hv
repeated use, become ciuite
mechanical.

Having recenth" had
occasion to so examine
numerous specimens of
Liassic and Keuper rocks, a simple piece of apparatus
which could be made easil}- and at small cost
became desirable. Unforeseen defects occurred
frequenth'. which rendered modifications necessary,
but the apparatus described below will be found to
work satisfactorih- for ordinary purposes. It is
a modified form of one described by Dr. J. W.
Evans (see Geol. Mag. 1891, page 67).

It can be made readily with a gla
spring clip

tubing. Figure 1 represents a section of the complete
apparatus. The funnel is cut off about half an
inch below the shoulder, and to the cut end is
attached a piece of rubber tubing about one inch
long. A spring clip like those employed with
burettes, either of Mohr's or Hofmann's pattern,
is fixed on this indiarubber tubing. The remaining
portion consists of a piece of glass tubing, having
the same, or nearly the same, bore as the stem of the
funnel, with a short length of rubber tubing at each
end. The construction is better seen in Figures
2 and 3. The lower end is provided w ith indiarubber
tubing of such a size that it forms a fairly tight fit
when pressed down into the funnel stem, while it is

funne

a thistle funnel, and glass and rubber

of smaller bore than the glass tubing. Since it has
to be stretched to fit on to the glass tube, the portion
which projects over the glass, and which should be
about half an inch long will form a truncated cone,
which will securely close the entrance to the stem
of the funnel when pressed down with a rotating
motion. At the upper extremity there are two
separate pieces of glass, which are used at different
stages in the manipulation. In the diagram
X is a piece of glass rod, or of glass tub-
which can readily be inserted
mto the short length of rubber tubing to render
that end air-tight. In Figure 3, Y is the head of
a thistle funnel, which can be similarly inserted.
Now as to the method employed in fractionating

(Figure 2)
ing closed at each end,
length

the
rins

ediments. The funnel can be fixed on the
^ of a retort stand or other convenient
support. The heavy solution of the particular
specific gra\it\ to be used is now poured in
carefully, to within a reasonable distance of the
top of the funnel. It will be found to be a good
plan to place the bottle under the funnel, and after
cautiously opening the clip slightly, to let a small
quantity of the liquid flow out, both to remove any
air bubbles and to ensure that the whole surface of
the rubber tubing is wetted.

The sediment or grains of matter to be separated,
which should previously have been washed and
dried, or treated in any way chemically, are now
poured on to the surface of
the liquid. The stopper
with the part X in the
upper end, may next be
used to stir the sediment
thoroughly into the liquid.
The object in having the
upper end closed by X
is to keep the stopper full
of air, and so prevent any
of the liquid entering it by
capillary attraction, in
which case grains are in-

the
the

variably taken up by
liquid, interfering with
success of the separation
at a later stage. The stopper
and the liquid is allowed to
hours. If tht_> hea\'\- liquid used

I-'IGLRK

■ ICL'RE

is now laid aside,
settle for several
is hygroscopic, the

217

218

KNOWLEDGE.

Junk, 1911.

funiifl sliould be covered by a piece of clean paper.
The heavy mineral ,t;rains should now collect in the
portion between the clip and the neck of the funnel.
When no further movement can be detected the
stopper is plunged beIo\\ the surface of the li(iuid.
and moved carefully to and fro several times, to rid
it of any grains which ha\e been carried down on
its low er extremity, and then inserted in the neck of
the funnel with a rotary motion which fixes
it firmly in the neck. The plug X is
removed and the thistle funnel liead "\'
inserted in its place. A second fniiiiel
with a folded filter pajier in it is placctl m
the neck of the solution bottle which i>
placed beneath the apparatus.

The clip is next opened (juickly. and
the li([uid from the portion below the
stopper flows out carrying with it the
heavy grains. More fresh li(]uiil is now
poured into the thistle funnel which fiows
down anil washes an\- adhering grains
out. The clip is then closed again.
The filtered liquid fiows back into the bottle
and can be used again, while the grainj
are retained on the filter i)aper (funnel A)
Figure 4.

The stopper is now removed, and put ,■

aside to be w^ashed. A third funnel with
filter paper is also placed in the neck of the bottle
which is again (placed below the apparatus. The
clip is opened again and all the li(|uid fiows out
carrying with it the b^i^btcr portion of the grains.
.\n additional arnimiit n| Hcpiid iioincd
in the separating tunnel will also How
out and carry witli it an\- remaining
grains which have adhered to the funnel
or tubes. The liquid will filter into the
bottle, while the grains will be retain(_'(
on this second paper (funnel B). All
that now remains to be done, i)reparator\-
to mounting for examination, is to wash
the grains thoroughl}-. The liquids used
being fairly expensive, it is also desirable
to perform this washing economicalh'.
The tollowing suggestions are offered
with a \-iew to collecting the washings
from the various funnels, papers, and Figure 5.

grains, for ct)ncentration. If all the
are so retained in a stock bottle and
call}- treated suitablw great saving is
since the resulting concentrated solution ma\' be
used for fresh separations.

There will thus be three funnels to be washed : —
(1) the separating funnel : (2) funnel A with the
heavy grains; (J) fuimel 15 with the lighter grains.

It is suggested that a retort stand with three
narrow rings, or any stand with three sui)ports
capabk' of holding the three funnels in such a
positinii that they are \eiticall\- over each other, be
used, b'igure 4 gives a diagrammatical represen-
tation of the arrangement.

In the top ring is the separating funnel, with
the sjiring clip removed and the stopper resting in it.

In the middle rint

tunnel B

rh has the filter
paper holding the lighter grains. The lowest ring
supports funnel .\ which has the heav\- grains on
the filter paper. It is advocated that these funnels
be arianged in this order for the following reason.
.\ny grains, which will belong to the lighter portion
of the separation, which ha\e not been
washed down ivnm the separating funnel,
NN ill tall down to funnel 1! \\ith the
washing \\;ilcr, and so join tlii' pro-
per set ol ,i;rains. It fininel A were
[)laced in the middle there would be
a danger of these grains getting into
the wrong set.

-V fine spray ot distilh.d water is directed
nil to the surface of the top funnel from
a wash bottle, and this water, after
cleaning that funnel, passes down through
r> and .\. finally enterini; the stock
buttle of washings placed underneath.
I'ue or six such washings should suffice
to clean the grains and a[)paratus.

The filter [japers bearing the grains
ma\' next be dried in a steam oven, or
'"' in any dry place free from dust.

The chief defect in this apparatus, which is
common to all similar ones, is that the separation is
not entirel\' reliable, owing to surface tension and
similar small attractions which are ine\itabl\' present
in the liipiid. h'igure 5 shows the
chief regions where these operate. In
the shaded portions the grains are
under slight attractions, due to the
above-mentioned causes: consequently
heavy grains which get into these mar-
ginal parts, ma\' iKit sink properly.

At X and \' particularlw there is a
tendenc}' tor the grains to climb up
the sides of the funnel, al)o\e the
mean le\el of the lii]uid, where the

ass

lopmj:

,da

w aslnngs
periodi-
effected,

meniscus touches the
sides. Great care and perse\erance
are necessary to overcome this and
other ine\'itable difficulties.

ISy keeping three sets ot this apparatus in use on
one stand tor liijuids of different densities, the grains
may be sorted into four sets.

Using litjuids of Specific Gravit}-, 2-7, 2-9, and
3-1, the following sets ma\- be obtained : —

(1) Specific Gra\it\' less than _'•/.

(2) Specific Gnwity between 2-7 and 2-').
(.5) Specific Gravity between 2-'' and .)•!.
(4) Specific Gravitv greater than .>• 1.

B\' increasing the
grains ma\- further be
restricted sets.

nuinlier ot
clitferentiatinl

quids, the
into more

THE MNEGAR INDUSTRY.

Bv C. AIXSWOKTH MITCHELL. B.A. (Oxoni. F.LC.

Notwithstanding the fact that the manufacture to three hours, the whole of the starch in the grain

of vinegar is one of the oldest industries in this has been converted into sugar b}- the enzyme,

country, and that in London alone there is an output diastase, present in the germ of the malt,

of several million gallons a vear, it is surprising how When this conversion is complete the icorf, as the

little is know n In- the outside world of the way in infusion is now termed, is drawn off, and, without

which it is made. being boiled with hops, as in the case of beer, is

This is largely the result of the policy of secrecv transferred to a fermenting tun, and treated with a

with which each firm of vinegar - makers
jealousK' guarded its methods during the
last century : although, as thev were work-
ing upon practically identical lines. the\' had
little to conceal from one another.

To such a pitch was this craze for secrecy
carried that some of the firms made use of
thermometers with marks upon them instead
of a scale, while others went e\en further,
and deceived their workmen bv the use of
thermometers in which the scales were of
set purpose graduated incorrecth".

suitable \'east.

In some \inegar works the wort is
obtained hv means of the conversion pro-
cess, instead of by mashing. In this process
the grain, usually rice or maize, without
malt, is treated with dilute mineral acid,
such as sulphuric acid, in a closed vessel
termed the converter. Under suitable con-
ditions the acid hydroh'ses the starch in a
manner analogous to that of the diastase of
malt, and produces a saccharine solution,
which, after neutralisation of the residual

Figure 1.
In ail the British factories, which in the B. Kiitziiigiaiiuiu. acid with calcium carbonate and separation
year 1840 numbered forty-eight, the methods

(Hansen).

Figure 2.

B. accti.
(Hansen.)

of working had been handed down within
the works themselves, and few attempts
were made to reduce to a minimum the
chemical and mechanical losses inevitable ^
during the manufacture. ^

During the last quarter of a century,
however, there has been a great improve-
ment in this direction, and many of the
factories now have up-to-date apparatus
and are under scientific direction, though
numerous examples of the primitive works,
universal fifty vears ago. still sur\ive.

There has been little alteration in the
general principles of manufacture in an\-
of the works, the process still
following the three stages of pre-
paring a saccharine infusion of a
cereal, of fermenting the sugar in
this into alcohol, and of trans-
forming the alcohol into acetic acid
by the action of bacteria.

Although wine vinegar is made to ^3^j__- s.o=c=t3-
a small extent in this country-, the o=cOc^ooO=>- ^'^=..s§^-==Cj
product chieflv sold is derived from
malt, or from a mixture of malt
with grain or sugar, and would
therefore be more correctly described
by the now obsolete term alegar.

The first stage of its manufacture
is very similar to the mashing
process in a brewer\". The malt, or

of the resulting insoluble calcium sulphate,
is readv for fermentation.

Bv whichever method obtained, the w cirt
is now pitched w ith yeast, and is aerated
and kept at the best temperature to
convert as much as possible of the sugar
into alcohol. Upon the successful
working of this stage of the process
^ largely depends the subsequent strength
of the vinegar, since all saccharine
matter i including dextrins) which has
escaped the action of the yeast, will
also remain unaffected by the acetic
bacteria. The fermented wort (now
termed ^j/e), which usually contains about
six or seven per cent, of alcohol, is

-'O.-.

;7c.JS??o:,^~^^^

now ready for the third stage — the
conversion of this alcohol into acetic
acid. This is brought about by the
action of specific bacteria, termed
acetic bacteria, which convey oxy-
sjen from the air to the alcohol, and
transform it into acetic acid. The
reaction that takes place in the
process is usually represented by
the formula —

Figure 3.

B. pastoriaimin.
(Hansen).

C.,H,0 + O.,
.\lcohol Oxygen

CoH.O, + HoO
Acetic Acid Water

Species of Acetic Bacteria multiplied
by 1000.

though, in practice, many other com-
pounds are formed, in addition to
aldeh\de. w hich is probably invariabh"
mixture of malt and grain, is first crushed between produced as an intermediate stage in the oxidation-
rollers and heated in a mash-tun with water at a C.,HgO -f- O = C.jH^O + HoO
gradually increasing temperature, until, after two Alcohol Oxygen .\ldehyde Water

219

220

KNOWLEDGE.

June, 1911.

The exact part playt-d by the bacteria in this
process is still obscure, and it has not yet been
ascertained whether the bacteria consume the
alcohol and excrete it as aldehvde and acetic acid.
or whether they contain an enz\ inc. the function of
which is to act, as platinum black can do (possibly

Figure 4.
Vinegar Fields in the year ISOO. Drawing off the Vint

bv setting up suitable vibrations in the alcohol), as a
carrier between the o.xygen and the alcohol.

The isolation of the enzyme, zyiiuisc. from \east.
and the proof that even in the form of a dr\- powder

dcdhol, led to repeated

it could ferment sugar int

efforts to isolate an analogous oxidising enz\me from

acetic bacteria : but, as yet, all such attempts to

express from the ruptured cells a liquid which after

filtration should produce the effect of the living

bacteria, have ended in failure. Several species of

acetic bacteria have been isolated.

differing from one another in their

form, in tlie temperatures at whicli

the\- work best, and in the nature

of the products that they yielti.

()f these the best known are thr

three species first studied in 1894

by Hansen and shown in the

accompan\ing illustrations. (Ser

Figures 1 . 2 and .S.)

All are cliaracterised by thi
different in\-olution forms which
thev assume when culti\ated upon
a suitable medium, under different
conditions. In each case when
grown iip(.>n the surface of a
nutrient liijuid, such as wort, at
a temperature of about .54" C.
(9.5" P.), the\' form pellicles upon
the surface, but the skin thus
produced differs m apjiearance.
that of B. act'ti being moist.
smooth, and >lini\'. while that ol
B. pastoriainim is dr\", and has a
corrugated surface.

In the case of B. Kiitziu^uimini
the cells are. as a rule, isolated, and the forma-
tion of chains rarel\- occiu's. whereas the occur-
rence of separate cells is the exception in the
case of the other two species. The cells of
B. dCL'ti are narrower than those of the others,
and nut infrequentK' show a form reseml)ling a

figure-of-eight, as was first noticed Iw' Pasteur.
The pellicle or skin formed by all these bacteria is
\\ hat is termed a zoogloeal form, and consists of the
cells united together into a tnass by the swelling and
fusion together of the outside cellular membranes.
PopularK- it is known as motlier-of-viiie}iai\ and
its excessive development in the
worts is an indication that in-
sufficient air is being supplied to
the bacteria.

The apparatus in which origin-
all}- this acetic fermentation was
effected consisted of nothing more
than barrels filled with wood shav-
ings, through which the wt.irt. after
being mixed with a little finished
vinegar containing the acetic bac-
teria, was allowed to trickle.
Hundreds of these casks were
ranged abo\(.' [)ipes communicating
with the gyle store vats, and were filled by means
of a flexible hose connected with the pipe. Each
day the bungs were uncovered, if the weather was
fine, in order to admit a 'fresh supply of air to the
interior of the cask, this process being continued for
many weeks until the acetification was complete.

The accompan\-ing illustration (see Figure 4)
represents a portion of the largest of these vinegar

fields (those of Messrs. Beaufoy & Co.) at
beginning of the nineteenth century.

the

\ " Sendiii.n-oiit " W.irehouse.

Ill, I klv 5.
Beaufov's Vinos

;r Warehouse in the ve.ir IHOO.

.\s these fields necessarily covered a very large
area the}- were obviously little suited for places where
land was valuable, .\part from that, fielding, as it
was termed, was a ver\- slow process of acetification,

and involved heavy wastage.

Hence, when.

1823, Schiitzenbach devised

JUNi:. 1011.

KNOWLEDGE.

221

more rapid method of acetification, his apparatus
was speedih- adopted in Europe, and more slowly in
this country.

The acetitiers emplo\-ed in w liat was then termed
the quick process consisted of large vats holding
from two thousand to three thousand gallnns each.
About two-thirds of the way down they were
provided with a perforated false bottom, and the
whole of the space above was filled with beech
shavings, while holes for the admission of air were
made in the side of the vat, just above the false
bottom, and smaller holes for its escape in the top.

The g\"le was constantly pumped over from the
bottom of the vat to the top. and trickling down
through the shavings met with a current of air,
which was drawn into the vat, under the influence
of the heat promoted by the reaction. About three
weeks were required for the complete conversion
of the alcohol into acetic acid.

The acetifying apparatus used at the present da\',
is essentialh- the same as that of Schiitzenbach, the
chief differences being in the nature of the packing
material placed in the vat, and in the method of
distributing the g\-le over the surface at the top, so
as to insure its reaching all parts of the aerating
medium.

In most acetifiers a sparger is used for sprinkling
the li(]uid over the material, and basket work is
commonl}" emplo\-ed in place of wood shavings.
The principle of the sparger is shown in P'igure 6,
which represents a section of the upper portion of
an acetifier.

The liquid is pumped from the bottom of the \at
and discharged into the funnel at the top, this
funnel being boxed in to prevent loss by evaporation.
Thence it flows down through the tube G. into the
sparger R, which revolves smoothly upon a pivot S.
In the arms of the sparger are a number of small
holes through which the liquid passes, and thus
causes the sparger to re\dl\e steadily and to sprinkle
uniformh- the whole of the surface of the basket
work, which is also shown in the figure.

A thermometer inserted through a hole in the
side of the acetifier shows the temperature within
the apparatus, and affords an indication whether the
acetification is following a normal course.

No more striking illustration of the manner in
which scientific text-books will copy errors from one
another can be found than in the assertions that are
put forward as to the temperatures at which acetic
bacteria thrive the best.

This is commonly given as about 90'' to 95 F..
and according to Brannt, " the formation of \'inegar
ceases entirely at 104" F." Yet the writer has
frequentK' seen the thermometers record a tem-
perature of 110- F., and there is no doubt that in
this country, at all events, the bacteria are most
active at a temperature of about 105 F. Possibly,
this may be the result of ada[)tation to the sur-
rounding conditions, since in Continental vinegar
works the temperature of the acetifiers seldom
exceeds 95° F.

The conditions for successful working are, firstly
a regular and uniform supply of air, and secondly
the right temperature. If too much air is
admitted the bacteria w ill oxidise part of the acetic
acid the\- have produced and a weak vinegar will
result. If too little air is available the acetification
proceeds ver\- slowly, the bacteria fonii themselves
into the zoogloeal condition mentioned above, and
the acetifier becomes clogged with slimy masses
which still further stop the passage of the air, so
that it forms currents in one portion instead of
effecting uniform aeration.

However carefulh' the process may be carried out,
the reaction never proceeds quantitatively in practice,
and the loss of acidit\', due to evaporation of the
alcohol and irregular aeration resulting in the
destruction of acetic acid, usually ranges from ten
to twenty per cent., and may, in very faulty apparatus,
reach as much as thirt\' per cent.

Most of the modern patents have had for their
object the remed\ing of these defects. Thus, in
some types of acetifiers, the air issuing from the
apparatus is carried back again into the vat, the idea
being, that the volatile constituents of the vinegar
w ill thus be prevented from escaping.

In others, attempts have been made to accelerate
the speed of oxidation, and thus reduce the period of
loss, by the introduction of ozonised air, but these do
not appear to have met with much success.

The key to the problem appears to be the provision
of a sufficiently large aerating medium through which
the air can circulate with absolute uniformity, and
experiments on a large scale, made by the present
w riter, have show n that so long as these conditions
can be maintained, the conversion of alcohol into
acetic acid proceeds almost in accordance with the
theoretical requirement.

After the vinegar leaves the acetifiers it is stored
ioT some time to form the ethers to which it owes its
aroma, and is then clarified by filtration through
large vats containing a suitable filtering medium, such
as fine sand. Finally it is diluted to the required
strengths, and is sent out to the trade.

From the davs i)f Charles II. to the reign of
William I\'. vinegar was under the control of the
Excise, and paid duty in accordance with its acetic
strength, \\hich was determined b\- the Excise
Officers by means of a special hydrometer, the vine-
gar being first neutralised b\" the addition of pure
calcium carbonate. Not until the year 1836 did
\inegar cease to be tested by the Excise Officials.

As it leaves the filtering vats, vinegar has an
acetic strength of 6 per cent., and upwards, and is
termed '' 24 \'inegar." Originally this name indicated
that one fluid ounce required 24 grains of sodium
carbonate to neutralise its acidity, but in the trade
the name is now applied to vinegars containing
5 • 5 }>er cent, of acetic acid and upwards. In like
manner, the lower strengths of vinegar are known
as ■• 16," " 18," " 20," and " 22," the lowest of these
containing 4- 1 per cent, of acid.

There is no legal standard as to the permissible

KNOWLEDGE.

Jl-ne, 1911.

dilution of vinegar, and a cheap vinegar containing
3-5 per cent, of acetic acid is often sold under the
name of " Diamond." .\ recommendation was
recently made. ho\\ever. in a report to the Local
Government Board that vinegar containing less
than 4 per cent, of acetic acid should not he sold,
and tlu're is 'a general tendency on
vinegar manufacturers to accept
this standard, which has been
upheld in undefended cases in
the ])olice courts.

With regard to what should
be the composition of the other
constituents in vinegar, there
is no agreement either among
manufacturers themseh-es or
among scientific authorities.
Should malt vinegar be brewed
entirely from malted barle\-. or
is any sort of malted grain
])crmissible ? According to the
ohl Pharmacopoeia malt vinegar
was to be brewed from a
mixture of malted and unmalted
grain, and if this is accepted.

rice must be regarded as quite as admissible as
barlew .Again, maize is largeh- used bv vinegar
makers, but the opinions of authorities differ upon
the [joint whether glucose derived from maize is
I)ermissil)le.

.-Ml these variations in the materials used
affect the hnal composition of the solid matter
in the vinegar, and prevent the analyst from

drawing deductions as to the origin of the (iroduct.
Thus a vinegar made entireh- from malt will
contain a considerable proportion of phosphates and
nitrogenous substances, whereas in a rice \'inegar the
amounts of these constituents will be verv much
less, and. in the absence of special knowledge to the
the part of contrar}', such a \'inegar might verv well be certified

as containing added acetic acid.
The so-called "wood vinegar,"
which consists of acetic acid
obtained by the destructive
distillation of wood and coloured
with caramel, is a perfectlv
wholesome article, and no ob-
jection need be taken to its
sale under its own name. The
legitimate vinegar maker has,
however, to meet the competi-
tion ()f the " vinegar faker,"
will I with the aid of no other
plant than a barrel of acetic
acid and a keg of caramel, is
able to put uj)on the market
a product which he sells at a
cheap price under such titles as
" Double refined malt vinegar." The occasional prose-
cution of the retailers of these concoctions does little
to check the evil, for the "manufacturer" promptly
leaves his "works." usualh' a back vard. and cannot
be found. It is not long, howexer. before he
re-apjiears under another name, and continues to
meet the popular demand for "pure malt vinegar"
at a price at which it Cduld not possibly be made.

Figure (?.
Section of Upper I'art of a Modern .\cetifier.

NOTICE.S.

.\ Xi:\V l'110Xl>GK.\I'H.— M. Lifschit^. ayoting Knssian
scientific man now working in Paris, has invented a phonograph
which uses photography for recording the \ibrations of human
voice.

He began his experiments in Russia but has continued them
in M. Dastre's laboratory at the Sorbonne, and there a
demonstration has been given before a small gathering of the
friends of science with a rough model constructed by the
inventor and M. Victor Henry.

The sonorous vibrations of the voice striUing a membrane
are thrown in the form of luminous images by a small mirror
upon a sensitive photographic film travelling at a high speed
as a band, and describe a curve upon it. Where the light
acts on it. the film is rendered hard and insoUiblc. The
other parts remain soft, and may be washed away.

For reproducing the voice the band passes before a " fente "
behind which is a chest of compressed air. .As the hollows of
the curve move rapidly before the " fente " the air as it
escapes reproduces the vibrations which caused them — in
other words it reproduces the vibrations of the human voice.

The word " curve " is used here in its scientific sense.
There are. in fact, "' makes " and '" breaks." Theoretically, the
membrane which actuates the mirror may be dispensed with.

M. Dastre is convinced that the new phonograph when
properly constructed, will give results far above those yielded
by mechanical phonographs of the lidison type.

Photographing vibrations is not new. What is new is the
combination of principles and the method of reproducing the
results of the photography. ., .- ..

STUNVHLKST COLLEGE UBSEKN ATOKV. — The
Report of the Director, Rev. W. Sidgreaves, S.J., F'.R.-A.S.,
for 1910. just to hand, shows a good record of work. It was
found that " the year's mean barometric pressure was a little
below the average, and of the month means only those of
March, September and October were above their respective
averages. These also were the drier months, the only ones in
which the rainfall was below the monthly average. But the
duration of sunshine was less than the average in September
and October. The highest reading of the barometer occurred
in March, and the lowest in F'ebruarj'. The former was a fine
dry month, the latter remark.able for its number of rainy days,
the greatest number recorded for F'ebruary in sixty-three years."
During the same period no January has shown so great
a rainfall as this, 8-043 inches, nor so great a fall in one day
as on the 15th. when 2-07 inches were recorded. Of the one
hundred and sixty-six days on which the Sun w-as observed
the disc was free from — presumably dark — spots on no less
than forty, and drawings were made on the remaining one
hundred and twenty-six. The mean daily area covered by
spots II being equivalent to 5n\,f)th of the visible surface! fell
from 3-8 in 1909 to 1-S in 1910. It is, however, remarkable
that the daily declination range of the magnetic needle
increased from 13-5 in 1909 to 14-5 in 1910. During the
year no %ery great magnetic disturbances were recorded,
though January 25th, March 27th, 2Sth and 30th, April 1st
and 27th. June 8th, 19th and 20th, .August 9th, 21st. 22nd and
28th, September 29th, October 4th, 6th, 12th and 27th, and
December 2Sth, are all recorded as great. ,. .- ,^

THE FACE OF THE SKY FOR JUNE.

Bv W. SHACKLETON, A.R.C.S., F.R.A.S.

The Sun. — On the 1st the Sun rises at 3.51 and sets at 8.4 ;
on the 30th he rises at 3.4S and sets at 8.18. Summer com-
mences on the 22nd. when the Sun enters the sign of Cancer
at 1.35 p.m.; this is the longest day, the Sun being 16" 34™
above the horizon. The equation of time is negligible on the
15th; hence this is a convenient day for adjusting sundials, as
only the correction for longitude is needed. Sunspots and
prominences are not very numerous; at the time of writing no
spots are visible. The positions of the Sun's axis, equator, and
heliographic longitude of the centre of the solar disc are
shown in the following table. An example of a disc suitable
for solar projection was shown on page 200 of the May issue.

Venus :

Date.

Axis inclined
from N. point.

Centre of Disc

S. or X, of
Sun's Equator.

Heliographic

Longitude of

Centre of Disc.

May JI

16"

s'n-

0° 43'S

•15° 59'

June 3 ...

14

u'W

0° 6'S

49" 40'

,, lo ...

12°

ti'W

0° 30' X

343° 3S'

„ 15 •

10'

5'W

I" 6'i\

277" 2S'

,, 20 ...

7"

55'W

1° 41'N

211° 16'

„ 25 ...

3

40' VV

2° !6'N

145° 5'

„ 30 ■■

J

25 'W

2° 50 'N

7S° 55'

luly 5 ...

i"

S'W

f 23 'N

12° 44'

The Moon :-

Date.

Phases.

11. M.

June 3 ...

,, II ...

,, 19 ...

,, 26 ...
July 3 ...

)) First Quarter ...

0 p-ull Moon

(I Last Quarter

• New Moon

D First Quarter

10 4 p.m.

9 51 P-"i-

8 51 p.m.
I 20 p.m.

9 20 a.m.

Jun-j II ...
,. 26 ...

Apogee

Perigee ..

10 42 p.m.
3 6 a m.

1

OcciLT.\TlONS. — The only naked eye star occulted before
midnight is the fifth magnitude star 22 Scorpii ; disappearance
takes place on the 10th at 9. 38 p.m. at an angle of 90 from
the N. point of the Moon, and reappearance at 10.55 p.m. at
an angle of 312".

THE PLANETS.

Mercury

Date.

Right Ascension.

Declination.

h. m.

June I

2 57

N 13" 6'

,, 11 ...

3 44

17° II'

2 !

4 54

21" 49'

July I ...

6 24

24' 21'

„ II ...

7 56

N 22° 37'

Mercury is a morning star in Taurus during the early part
of the month. On the 1st the planet rises in the E.N.E. at
3.10 a.m. ; on this date Mercury is at greatest westerly
elongation of 24° 30', from the Sun, but the elongation is ail
unfavourable one on account of the planet only rising 40
minutes in advance of the Sun.

Date.

Right Ascension,

Declination.

li, ni.

June I ...

7 36

N 24° 0'

II ...

S 23

2I-' 42'

., 21 ...

9 7

■8' 35'

July I ..

9 47

14" 52'

II

10 22

N 10° 46' .

Venus is a brilliant object in the evening sky looking W'.X.W.
immediately after Sunset.

The planet is extremely well placed for observation,
appearing high above the horizon at Sunset and not setting till
11.20 p.m. on the 1st and 10.37 p.m. on the 30th. Moreover,
the planet can readily be seen long before it is dark and even
in broad daylight a small pair of opera glasses is sufficient
optical aid to render it visible if directed to the correct
position in the sky. The best time for observing is whilst the
background of the sky is still light, for the brightness of the
planet is so intense that it requires an uncommonly good
telescope to observe when dark, partly because the planet is
then lower in the sky and partly on account of the luminosity
of the planet being strong enough to reveal any lack of
achromatism in the telescope ; thus in poor instruments a blue
halo frequently appears to surround the image. With magni-
fying powers of 150 to 250, dark shadings may be seen on
the planet's disc towards the terminator, the limb appearing
intensely brilliant. As seen in the telescope the planet appears
slightly gibbous 0'6 of the disc being illuminated, whilst the
diameter of the disc is about 20". The Moon appears near
the planet on the evening of the 29th.

M.\RS : —

Date.

Right Ascension.

Declination.

June I ...

,, II ...

., 21 ..
Tuly I ...

,, II ...

h. m.

2 J 59
0 26

0 52

1 IS
I 44

.S 2^' 10'

N 0° 38'

3" 23'

6" i'

N S' 29'

Mars is a morning star in Pisces, rising nearly due E. early
in the month, and later a little N, of E, On June 1st, the
planet rises about 1.30 a.m., and on July 1st. about ten minutes

I'u;i'Ki'; I.
Ccmjunclion of Mar.s and the Moon, June 21,

after midnight. The planet is increasing in brightness the
apparent diameter being now nearly 8". On the morning of

223

224

KNOWLEDGE.

June, 1911.

:he 21st. at 1 a.m. the Moon is in conjunction with the planet,
Mars being only 0' 12' to the nofth isec I^iKure 1).

Jupiter: —

Saturn

Date.

Kii;ht .Ascen.sion.

Declination.

June 1 ..

., II ...

,, 21 ...
July I ...

,, II ...

' h. 111.

14 i:
14 14

14 -
14 II
14 12

.S 12° 19'
12" 7'
1 1 " 59'
1 1 ° sS'

S 12° ~i'

Jupiter is a brilliant object in the evenini; sky looking South,
and is in the very best position for observation. Near the
middle of the month the planet is on the meridian at 8.45 p.m.,
but observations m.ay commence as soon as it is dark, since he
is above the horizon at Sunset.

The planet is describing a retrograde path near a V'irginis
and is at the stationary point on July 3rd.

The most noticeable features as seen in the telescope are
the moons, the dark belts, and the polar flattening ; this latter
is shown by the equatorial diameter being 41"- 6 and the polar
diameter 2"- 7 less. If sufficient magnifying power be used
with a telescope of about four inches aperture, markings and
also the " Great Red Spot " on the belts may be observed,
from which the period of rotation may be deduced. This is
only Q'" 53'". which explains the cause of the obl.iteness of the
planet.

The following table gives the satellite phenomena visible
before midnight : —

V

c

= P.M.'s.

SI H. ,M.

1

,1

Phenomenon.

2

1

CO

d
c

c

i

S P.M.'.s.

!X H. M.

[lint

June

June

I

Tr. E. Q 44

Q

11.

Ec. R. II 3S

33

I.

Oc. 1 ). 10 8

I

Sh. K. 10 2S

11

111.

Ec. R. 9 38

24

I.

Tr. E. 9 36

8

Tr. I. q 20

15

1.

Tr. I. II 8

24

1.

Sh. E, 10 41

8

Sh. I. 10 10

16

11.

Oc. D. g 42

25

II.

Sh. E. II 19

8

Tr. K. II 31

It)

1.

Ec. R. 1 1 26

Ill

Oc. 1 1. II 42

9

Ec. R. 9 32

iS

111.

Oc. R. 9 42

"Oc. D." denotes the disappearance of the Satellite behind the disc, and
" Oc. R-"_its reappearance: " Tr. I." the ingress of a transit across the disc, and
" Tr. E." its egress ; " Sh. I." the ingress of a transit of the shadow across the disc,
and "Sh. E." its egress; " Ec. D." denotes disappearance of Satellite by Eclipse,
and " Ec. R." its reappearance.

The configurations of the satellites as seen in an inverting
telescope and observing at 11 p.m. are as follows: —

Da)-.

West.

East.

Day.

West. East.

I

4321 O

16

43 0 92 91

2

34 O 21

17

431 0 2

3

31 0 4 2

iS

42 IJ 3 I

4

2 O 314

iq

241 (_^ 3

5

■; 0 34

20

I > 4123

6

0 1234

21

I I-'' 5 4

7

1034

22

23 0 14

8

32 0 4

23

32 0 4 •!

9

3 0 14 •z

24

31 0 24

10

3' 0 24

25

23 0 I 4

1 1

2 0 J I

26

21 0 34

12

U 0 3

27

0 ■; 43

'3

4 0 123

28

'4 0 5

14

41 0 I

29

423 0 I

15

423 0 I

30

4321 0

The circle (O) represents Jupiter; O signifies that the
Satellite is on the disc ; • signifies that the Satellite is
behind the disc, or in the shadow. The numbers are the
numbers of the Satellites.

Date.

Right Ascension.

Declination.

June I ..

., 16 ..

July 1 ..

11. 111.
2 47

2 54

3 0

>•■ 13° .S3'

H" 22'

N 14° 47'

Saturn is a morning star in Aries, rising E.N.E., about
3 a.m.. on the 1st June, and at 1.7 a.m. on the 30th. In con-
sequence of the planet being in a bright portion of the sky he
is, for all practical purposes, unobservable.

Ur.ANUS : —

Dale.

Right .Ascension.

Declination.

luiic I ...
July I ..

ll. 111. s.

20 5 14
20 I 28

S 20" 53' 49"
S 2P' 5' if

Uranus rises in the S.E. at 11.20 p.m. on the 1st, and at
9.23 p.m. on the 30th. The planet is unfavourably placed for
observation, as he is low down in the sky ; he is describing a
retrograde, or westerly, path, about 2° S.E. of f Capricorni ;
he can just be discerned with the naked eye on a very clear
night, but is easily visible through a pair of opera glasses.

Neptuxe : —

Date.

Right Ascension.

Declination.

June I
July I ...

ll. 111. s.

7 25 15
7 29 35

N 21° 24' 49"
N 21" 16' 20"

Neptune is practically unobservable as he sets at 11 p.m.,
on the 1st and at 9 p.m. on the 30th.

Meteor Showers: —

Date.

Radiant.

Name.

Characteristics.

R.A.

Dec.

June-July ...
June 13

h. 111.
16 48
20 40

— 21"
+61-

a Scorpiids
a Cepheids

t

Fireballs.
Streaks, swift.

Mira lo Cetit is due at maximum on the 30th. but obser-
vations should be made before and after this date as the
period is somewhat variable. The magnitude at maximum is
usually about 3'0 but this, too, is variable. The spectrum at
maximum is a mixed one exhibiting both bright and dark lines.

Telescopic Objects : —

Double St.\rs, &c. — 7 Virginis .\II." 37'", S. 0" 54', mags.
3, 3, separation 6"-0. Fine doable for small telescopes with a
magnification of about 80.

/i Scorpii, XVI." 0'", S. 19 34', m.ags. 27, 5'2 ; separation
13".l.

e Lyrae, XVIII.'' 41'". N. 39° if, known as the "double-
double " star, can just be separated by the naked eye, but with
a pair of opera glasses it is readily divided into two components,
fi and f-i, mags. 4'4 and 4"8. Using a 3-in. telescope and a
power of about 120, each of these stars can again be divided
into pairs, 3"'2 and 2"'6 apart respectively, each component
being about magnitude 5'5.

M 57 (Lyra), the "ring" nebula. This nebula is the only
annular nebula accessible to telescopes of about 3-in. aperture,
and even tiien requires good seeing. It is easily found, being
situated about 3 of the distance from /^ to 7 Lyrae. The
usual appearance in a 3-in. telescope is that of a rather large

June, 1911.

KNOWLEDGE.

225

nebulous star, but it bears magnification well, and its annular
character can easily be made out with a moderately high
power.

M SO (Scorpio). A compact globular cluster half way
between a and li Scorpii ; looks Ukc a nebula iu small
telescopes.

QUERIES AND ANSWERS.

Rcailcrs arc invited to send in Questions and to answer the Queries which arc printed here.

UU ESTIONS.

41. THE EFFECT OF RIGID RAILS ON THE
SPEED OF A TRAIN. — A pendulum shows that, as one
walks towards it, one makes a dimple in the ground.

1 ha\e often observed the dimple which is made by a
running locomotive.

As the engine is continually climbing out of consecutive
dimples, a question arises — is the speed of a train lessened
thereby, and would the train travel faster if the rails were
absolutely rigid ? Francis Ram.

42. THE CARRI()N CROW.— Can any of your readers
inform me whether a clutch of nine crow's eggs has been
recorded ? I found a nest in the Hrent Valley this Spring
containing eight greenish-brown eggs and one greenish-grey.
The eight were at the bottom of the nest, and the other on
top of the others. Geoffrey Ker Webb.

43. .\STRONOMY. — Of what value is " Urania's Mirror,
or a View of the Heavens" (published by Sleighl, consisting
of 32 coloured plates, engraved by Sid. Hall, sculptor '-

A. M. F.
REPLIES.

31. It has never come to my ears nor eyes that wireless
telegraphy did or would have anything to do with changes in
the weather, but to me it seems feasible and likely.

The entire universe is built upon \ibrations, and electrical
forces and storms are no exception. If it is true that wireless
telegraphy may, in a measure, influence weather conditions, it
is because of the vibrations of the electric and air waves it
sends forth from the central station. Of course, the greater
the electricitv generated the greater the change in the weather.
I can go no further and state why these vibrations should
cause any change in the weather, hut will give a few examples
we have all seen or heard,

A heavy peal of thunder during an electrical storm — one
that jars the house and shakes the windows — is. in almost all
cases, followed by a heavy downpour of rain. The terrible
convulsions of the atmosphere during tornadoes, frequent in
the southern states of the United States and the hurricanes of
the West Indies, are invariably followed by torrential rains.
Whirlwinds coming out of a clear sky are immediately followed
by clouds and storminess. The fair weather preceding an
earthquake is quickly changed, after the vibrations and tremors
of the earth, into cold, cloudy and rainy conditions. After all
great battles, where heavy cannonading has been going on for
any length of time, rain is sure to fall with the gathering of
clouds soon after. Even during the .American Independence
celebration, rain generally falls at night in the places where
the most fireworks have been set off, no matter how clear the
weather had been during the day. Allow me to go one step
farther and say that all the planets, as electric dynamos, are
sending forth vibrations throughout space which causes the
ocean tides and the varying storm and weather conditions
upon ours and other whirling globes, ^ j^^ Pritchard,

39. ANTICYCLONE.— It is ijuite true that an anticyclone
is not always the opposite of a cyclone as regards the actual
strength of the wind, but there are certain properties of these
systems which make them diametrically opposed. (1) The
wind circulation is anti-clockwise in a cyclone, but clockwise
in an anticyclone, (21 Pressure is highest at the centre of an
anticyclone, but lowest at the centre of a cyclone; and, there-
fore (31 the wind circulates spirally outwards iu an anticyclone,
but spirally inwards in the case of a cyclone. (4) Comparatively

speaking the calmest area of an anticyclone is at its centre,
whereas the windiest area of a cyclone is at its centre. Thus the
term "' anticyclone " does not always infer quiet weather.
There is sometimes a difficulty in that there is no hard and fast
boundary between the edge of an anticyclone and that of a
cyclone ; one canrtot always say how much of the wind's strength
is due to one system or the other. Thus the term " anti " is
justified in four respects, not to mention the fact that an
anticyclone usually drifts or remains stationary, whereas a
cyclone generally has a much faster motion in a certain

'^'^^'^''°"- ' C, H. E. R[(M.ATH.

40. WATER- FIN DING. —No scientific explanation is
yet attainable. The supposition of those who have most
thoroughly studied the phenomena is that some people can
sub-consciously perceive underground water, and so on. by a
kind of sixth sense, and that the sub-consciousness signals its
discovery by twitching the muscles and thus moving the rod.
The only scientific treatment of the subject at any length is
in Professor W. F. Barrett's reports in the " Proceedings " of
the Society for Psychical Research, Vols. 13 and 15. A
condensation is given in his pamphlet " On the Hi'story and
Mystery of the so-called Dowsing or Divining Rod," obtainable
for Is., from the Secretary. Society for Psychical Research.
20. Hanover Square, London, W,

J, Arthi'r H[li.,

5S. H.ALLEY'S COMET. — "Interested" asks a question
with reference to the determination of the distance of Halley's
Comet from the Sun, and also its velocity, at any time, say
two >ears after passing Perihelion, .April 19th, 1912.

The following easy method can be used, when the pertur-
bations of the planets are not taken into consideration.

Let the figure represent the path of the Comet in its orbit,
where A.-^' is the axis major of the ellipse described, S the Sun
in one of the foci of the ellipse, C the centre, and M the
Comet two years after passing perihelion. Of course A will
represent perihelion point.

We assume the following data in connection with Halley
Comet : —

... 76

Periodic time
Perihelion distance
Eccentricity ...
Aphelion distance

35

37 years.

5889 Astronomical Units.

967

411 .Astronomical Units

the radius \ector is called the

The angle ASM described b\-
" True Anomaly," and is generally denoted by v ; the angle
described by the radius vector on the assumption that it
moves uniformly, is called the " Mean .Anomaly " : it is usual
to denote it by M. Now, if we suppose a circle circumscribed

226

KNOWLEDGE.

Junk, 1911.

round the ellipse, and we draw through M an ordinate meeting

this circle in M'. the angle ASM' is called the "Eccentric

.Anomaly." denoted by u.

From the properties of an ellipse the equation

M = u — e sin u is easily deduced, where e is the eccentricity.

V, ,, ^60° ' , „

.Now Ml = j^.^-j X 2 = 9 25 40

.•. 9° 25' 40" = u - -967 X 57 -3 sin u.

The factor 57°- J is introduced, since this is the number of
degrees in one radian.

This e(|uation can be solved appro.ximately by a Graphic
Method; the one used is the well-known method by drawing
a Curve of Lines. .As a first approximation u comes out
about 55 \

To find its e.xact value, let u be actually 55^ + (*". where 0 is
small.

.-. 9° 25' 40" = 55° + W° - -967 X 57;3 sin (55° + tf°).
Now sin 155 +<'"! = sin 55° cos e° + cos 55" sin 0°

= sin 55^ + ~^fTJ~ '^"^ ^^°'
since cos " = 1 nearly, and » =
as 0 is very small.
We.therefore, obtain 45 ' 34' 20" + fl° =

■967 X 57-3 ( ■,S1915 +

or 0° + 45-57222 =-- 45-387 + -55467 «°
•44533 tf° = - ■lcS5
.-. y° = - .4157° = _ 24' 26"
Hence, value of u is 55" — 24' 26"
= 54° 35' 34".

The True Anomaly v is given by the formula

tan i v=a/ y^? tan h u
^ 1 — e

= 7-72 tan 27' 17' 47"

= 7-72X -51606 = 3-9814

:.h v = 75' 54'

or v = 151° 48' .-ipproximately.

e

57-3

■57358
57-3

If n be the distance of the Comet from the sun, r is given
by the formula r = a (1— e cos u), where a is the semi a.xis
major, or 18 astronomical units

.•. r=lS (1 — ■967 cos 54° 35' 34"l
= 18 (1-- 56028)
= 7-91496

Its distance from the sun would, therefore, be about eight
times the distance between the sun and the earth. It would
be, at this time, between the orbits of Jupiter and Saturn.

The formula to determine the velocity at any point in the
orbit distant r from the sun is

V " — ^

r a

where m is a constant, and a the sun's axis major. Substitut-
ing 7-91 for r. and 18 for a. we find

V-=-1979 n
.•.V=-445 s 7

The constant m can be found from a consideration of the
motion of the earth in its orbit. .Since the comet describes
an ellipse around the sim, p- will be the same for the earth and
the comet. Using the eijnation

.„_2"_M_

V —

r a

for the earth, and remembering that r = a very nearly, since
the eccentricity of the earth's orbit is only nV, we have

a

Now. the \elncity of the earth around the sun is about
eighteen and a quarter miles a second, and a=l astronomical
unit, therefore M = (lS-25)^or \ M = 18-25. Substituting in
the expression \'= ■ 445 \ m. we have V= ^445 X 18-25 = 8^ 12
miles per second.

The perturbations produced by the planets will slightly alter
some of the elements, but the above results ma\- be taken as
approximately correct. ,|.,_^., ^,^ Davidsox.

POST.AL REFORM.

The cost of postage presses very heavily upon magazines
which cannot be registered as newspapers, and it seems
rather hard that a newspaper weighing several pounds can
be transmitted through the post for a half-penny, when
scientific journals and the transactions of societies, which
tend to the spread of knowledge, and the advancement of
science, may cost six, or eight, or ten times as much. We
have therefore nuich pleasure in printing the resolutions
which were passed unanimously at a large and influential
meeting, convened by Mr. Edward Owen Greening, on
.April 6th, at the offices of the Horticultural .and Agricul-
tural .Association, and we are sanguine that at last some real
good may be done.

1. "That this representative gathering of proprietors,
publishers, and editors of magazines and trade journals
earnestly protests against the present unfair, unequal, and
excessive postal rates upon periodicals published at intervals
longer than a week, the British Post Office arrangements being
more oppressive than those of any other ci\ilised countries in
postal charges on this important kind of literature. The
present postal treatment, by restricting circulationof magazines,
depresses the remuneration of authors and artists, renders it
difficult for British publishers to compete with those of other
countries ; enhances prices to the public, and reduces the
benefits which can be given to readers of such periodicals
which are largely instructors in matters of science, art, manu-
factures, commerce, philanthropy, and religion."

2. " That in view of the huge surplus profits on postages
amounting to five millions sterling per annum, and averaging

over 26 per cent, on the business, we cannot accept the
declaration of the postal authorities that they are unable to
afford reform. We deprecate postal forecasts of possible
losses on reductions, as these gloomy anticipations are always
falsified in results. We claim that postal revenues are
properly applicable to postal purposes, and should be used to
reform evils, remove anomalies, and redress grievances of the
public which uses the Post and the employes who serve it.
We regard the abstraction of postal revenuesby the Exchequer
as a virtual act of confiscation, degrading the Post Office from
its proper position into a tax-collecting department of the
Government. We demand that fair treatment shall be given
to us. equal to that enjoyed by publishers in America, Canada,
and so on, before the postal surpluses to which we contribute
arc alienated by the Exchequer."

3. " That we, now present, pledge ourselves to form an
organis.ation to press for the neces.sary postal reforms, and to
supply resources for an effective movement.

" That we appeal to all magazine proprietors and editors
regularly to devote space in their columns to public enlighten-
ment on the questions at issue. That we appeal to our
colleagues of the daily and weekly journals for their good
help. That we seek the aid of friends of the Press in the
Legislature to organise active Parliamentary action."

4. " That a General Committee be elected with powers to add
to their number, to appoint an Executive and officei's : to
increase adherents to the cause by canvass and otherwise
conduct our nii)\ i-nn-iit to a successful issue."

THE BRINE SHRIMP.

Bv W. T. CALMAX. D.Sc.

The pretty little Crustacean known as the Brine
Shrimp was first discovered about the middle of the
eighteenth centur\at L\"mington. in Hampshire. In
those da\s, and for something like a century after-
wards, the manufacture of salt from sea water was

carried on there and at
other places on our coasts,
the hrst stage of the pro-
cess being the concentration
of the sea-water by exposing
it to evaporation by the
heat of the sun in large
shallow ponds. The con-
centrated brine was then
into open vats known

run

to
b\-

Figure 1.

The Brine Shrimp.

Artciiiiii salina.
Female, from below.

The line indicites actual length.
(.\fter G. O. Sars).

as " salterns." previous
being further evaporated
artificial heat, and
it was in these
vats that the Brine
Shrimps, or " brine-
\\orms" as thev were
called, appeared in
such numbers as
to give the brine
a reddish tinge.
Thev were believed
to be of service in
clearing the liquid from im-
purities, and the workmen
were in the habit of trans-
ferring some of them from
one " saltern " to another,
when they did not make their appearance naturallw
to ensure their presence when the brine had
reached the proper degree of concentration. Brine
Shrimps ha\e since been found in many parts
of the world in natural or artificial brine-pools
and lagoons and in salt lakes, and, although
a number of species have been described, there
is reason to believe that they are all forms of
a single variable and cosmopolitan species, Arteinia
salina, which ranges from Greenland to Australia,
and from the Great Salt Lake of Utah to Central
Asia.

The Brine Shrimp belongs to the sub-class
Branchiopoda, which includes the most primiti\e
of existing Crustacea, and it is closely allied to
the " Fairv Shrimp," Chirocephaliis diaphaiiits.
recentlv described in the pages of "Knowledge"
(July, igiO), by Mr. G. W. Pyman.

The body of Arteinia is usually about half-an-inch
in length. Like that of Cliiroceplialiis it is worm-
like and completely divided into segments, without
a protecting shield or carapace, such as is found in
most other Crustacea. The first eleven segments
behind the head each carry a pair of flattened fin-like

Figure 2.

Nauplius larva,
just hatched,
highly magnified.

feet, bv the rhythmical movements of which the
animal swims. The hinder part of the body forms
a slender tail and is without appendages. The head
bears a pair of compound eyes set on movable stalks
and a third eye, very small and of simple structure,
in the middle line in front : the three e3-es are
coloured with dark reddish-brown pigment. There
are two pairs of feelers, the first pair, or antennules,
slender and thread-like, the second, or antennae,
short and stumpy in the female, but \er\- large in
the male, and forming a pair of curiously-shaped
claspers for seizing the female. The female, when
fullv mature, carries her eggs in a sac-like receptacle
on the under-side of the body at the base of the tail.
The animals are generally of a pale reddish colour,
owing, as Sir Rav Lankester first showed, to the
presence in the body fluids of haemoglobin, the

substance which gives its colour to the

blood of \'ertebrates but is not often found

in Invertebrate animals.
The Brine Shrimp

Branchiopoda. usually

wards, and it feeds

on minute floating

organisms and parti

like most of the
swims back down-

cles of organic matter

(Afler G. O. S.-irb).

which are drawn in

towards the mouth by
the movements of the feet.
The phenomena of re-
production are of particular
interest. Like many, but
not all. of the Branchiopoda
the Brine Shrimp repro-
duces extensively by par-
thenogenesis, that is to
say, the females lay eggs
w hich are capable of devel-
opment without being ferti-
lised. In some localities,
in fact, it appears that
males are never found,
the colonies consisting
entirelv of females. In
other localities the two
sexes occur in nearly
equal numbers, and repro-
duction takes place by
fertilised eggs. There
is some evidence to show that there may be two
races of Brine Shrimps, the one e.xclusively
parthenogenetic, the other sexual, but it is by no
means clearlv ascertained what the exact relations
between the two forms are.

The eggs are globular in shape, about one-
hundredth of an inch in diameter, and when
deposited are enclosed in a tough shell which

Figure 3.

The Brine Shrimp,

Art cm ia salina,

Male, from above.

(After G. O. Sar>).

227

228

KNOWLEDGE.

June. loil.

enables them to survive being dried. In this
condition the eggs may be carried long distances in
mud. adhering to the feet of wading birds, or may
be blown about by the wind, and the distribution of
the species from one localit\' to others is thus
rendered possible. Sometimes, however, the Brine
Shrimp is viviparous, the eggs hatching while
still within the brood-sac. and before the shell has
been completely formed. In either case, the \-oung
appear first in the form of tiny si.x-legged lar\ae
with an oval unsegmented bod\- and a single eve.
This type of larva, known as a imiiplitis, is found in
many other groups of Crustacea, such as Copepods.
Barnacles, and some of the true Prawns, which
in the adult state are very different from the Brine
Shrimp. In the course of development the bod\-
elongates and becomes di\'ided into segments, the
eleven pairs of swimming feet successively appear,
the stalked eyes grow out at the sides of the head,
the three pairs of nauplius limbs lose their
swimming branches and become the antennules,
antennae, and mandibles, and the animal graduallv
acquires the form and structure of the adult.

The great variability of the Brine Shrimp, alreadv
alluded to, seems to be correlated with the \ar\ing
chemical composition antl concentration of the
solutions in which it li\es. It lias been found in
water containing no less than _'7 per cent, nf
dissolved salts, while on the other band it sometimes,
though rarely, occurs in water that is quite fresh.
In Central Asia, Brine Shrimps ha\-e been found
living in lakes containing so much sodium carbonate
that the water had a distinctly "soapy" feel. A
Russian naturalist, Schmankewitsch, showed, many
years ago, that it was possible, by breeding Artemia
in solutions of varying concentration, to produce
changes of form, especially in the end-lobes of the tail.
Some of the characters thus produced had pre\-iouslv
been regarded as distinctive of separate species, but
there is no ground for the statement sometimes made
that the e.xperiments resulted in changing one species
into another. They simiily showed that the species

had been mistakenly separated on variable and
untrustworthy characters. The statement that some
of the specimens assumed the characters of the
allied but (juite distinct genus Branchipiis has since
been shown to be erroneous.

The manufacture of salt from sea-water in the
way described above has long since ceased in this
countr}-, though it is still carried on on the shores of
the Mediterrannean, and it is probably many years
since the Brine Shrimp became extinct as a member
of the British fauna. An accidental observation
recently made at the Natural History Museum
shows, however, that it is probabK' a ver\- simple
matter for anyone to obtain a supply of living
specimens. A solution of " Tidman's Sea Salt."
which had been set aside and forgotten, was found
after some weeks to have about a dozen full-grown
Brine Shrimps activel}- swimming about in it. All
of these were females and carried egg-pouches full
o( eggs, which were deposited shortly afterwards and
in a few days the larvae of a second generation were
hatched from them. .\ fresh packet of the salt was
then experimented with. About eight ounces were
dissolved in five pints of tap water, and microscopic
examination of the sediment showed that it
contamed numerous eggs. In about four da\'s a
swarm of nauplius larvae issued from these, and
in the course of a fortnight thev were well on
the way to assume the adult form, although still
\ery small.

It is impossible, without further trial, to say
whether eggs capable of development are always
present in Tidman's Sea Salt. The\' cannot retain
their vitality indefinitelw and, in fact, a \'ery old
sample of the salt found among the Museum stores
proved to be barren of lite. It need hardh' be said
that salt which in the course of manufacture has
been exposed to artificial heat, would contain no
living eggs. In repl\- to an inquir\- on this point
Messrs. Tidman & Son kindly stated that their
Sea Salt is manufactured abroad from sea-water
evaporated b\- the sun"s heat.

NOTICE.

THE SOUTH AFRICAN JOURNAL Ol- SCIENCE.

— In the April issue of tlie Soiifli African Juiirnal of
Science appear notes on Croialaria Burkcana and other
leguminous plants causing disease in stock. Beasts eating
Crotalaria develop laminitis within a few days, their hoofs
grow long and, unless attended to, the beasts get so stiff in the
joints that they lie down and are unable to rise again. Goats
seem to be immune and it is curious to note that the same
fact is recorded in the case of Cytisus proliferus m the
Canary Islands. This Cro?a/rt)-((7 is recorded from the Trans-
vaal, Orange Free State, the Cape Province and Natal and
there is one record from Zululand. It is most common on sandy
soils and it is found that even if it exists in the unbroUen veld
in such small quantity as to be harmless, as soon as the land
is cultivated and maize or kaflir corn planted, the Crotalaria
makes its appearance along with them. The plant is said
to be most poisonous when the pods, called 1>\ the Boers
" Klappers," have developed. In the Eastern and Central
United StateaCrotalaria sagitfalis or " Kattle-box" produces
a stock disease called " Crotalisni " or "Missouri bottom
disease," which is more frciiaentl\- fatal than tliat induced

by the South African lliirl;cana. Other species oi Crotalaria
in Australia arc known to be injurious to stock. The notes
also record the effect of Lcssertia, Melolohinni and Cytisns,
in Africa ; Swainsona galeiiifolia (Darling pea or indigo) in
Australia; Astragalus, Oxytropis and Sophora, in America.
In the same number Ur. P. D. Hahn describes a geyser in
Rhodesia, the only one that has been discovered in that
country. The geyser is situated near Fulunka's Kraal,
about two miles south of the Zambesi River and forty miles
below the confluence of the Gwai River. It issues from a
round hole, about two inches in diameter, in solid sandstone
and throws up a continuous stream of water eight feet high.
The temperature of the water is slightly below boiling point ;
the force with which the water is expelled is not great, as the
geyser can be easily plugged with a stick, while a ten pound
stone placed over the aperture will stop the play of water.
Analysis shows the silica content of the water to be 13-65
grains per gallon. The water of ordinary springs, either deep-
seated or surface, rarely contains so much as one grain of
silica per gallon, while the Iceland geysers show from eleven
to thirt\'-fi\e grains.

NOTES,

ASTRONOMY.

By A. C. D. Crommelin, D.Sc, R.A.

ENCKE'S COMET. — Dr. O. Backlnnd has recently
published some further researches on this comet. The
observations of each return since 1891 have been compared
with theory. The dates of perihelion (all expressed in Berlin
mean thne") are:— 1S95. February 4-785; 1898, May 26-898;
1901, September 15-501; 1905, January 11-916; 1908, April
30-946; 1911, August 19-0656. The mean daily motions at
these returns is 1070" plus the following: — 3"-934, 4"- 157,
3" -625, 5" -084, 5" -848, 5" -668. The other predicted elements
for 1911 are:— Node, 334° 29' 32"; Omega. 184' 39 '29" ; i, 12°
34' 32"; e, 0-845723. The most interesting feature of this
comet is the acceleration of its mean motion. Dr. BacUlund
finds evidence that this suddenly changed its amount in 1858,
1868, 1895 (beginning), and perhaps 1904 (end). Several of
these dates are near sunspot nia.ximum, and it is suggested that
the cause is to be sought in some solar disturbance.

The comet was extremely faint at its last return, in 1908,
and was only obtained (by photography) at the Cape Observa-
tory. It is not thought that this means any permanent loss of
light, as it had often before been very faint when in a similar
position with regard to the Earth. It is brightest at winter
returns, of which the next will occur at the end of 1914; at
these times it is quite a conspicvious telescopic object, and is
sometimes visible to the naked eye. Before its periodicity
was known it was independently discovered at three consecu-
tive winter returns — those of 1786, 1795, 1805 — which shows
that it nuist have been a fairly conspicuous object. The
following is an ephemeris for the present year, for Berlin
noon : —

R.A. N.Dec. R.A. Dec.

July

Aug

1 .

. 4 16 17

28°

14'

5 .

. 4 35 26

28°

54'

9 .

. 4 56 15

29°

26'

13 .

. 5 18 50

29°

46'

17 .

. 5 43 18

29°

52'

21 .

. 6 9 40

29°

38'

25 .

. 6 37 54

29°

1'

29 .

. 7 7 52

27°

54'

2

. 7 39 20

26'

14'

Aug. 6... S 12 3 23° 55'

„ 24. ..10 44 31 5° 46'N.

„ 2S...11 16 6 1° 2'N.

Sept. 1...11 46 24 3 28' S.

,. 5. ..12 15 45 7 ' 41'

„ 9. ..12 44 22 11° 32'

„ 13. ..13 12 17 14= 59'

.. 17. ..13 39 27 18° 2'

,, 21. ..14 5 44 20' 38' S.

If seen at all in luuope it will be in July. It will then be
about one hundred and fifty million miles from the Earth.

HALLHVS COMET.— This is still being diligently
followed at the Yerkes Observatory. Popular Astroiioiiiy
for May contains a reproduction of a photograph taken by
Mr. F. Slocum with the two foot reflector, with one hour's
exposure. The comet appears quite distinctly as a short
trail. It was then one hundred and ten million miles further
from the sun than on September 11th, 1909, and yet \ery
much brighter, showing that the physical brightening at
perihelion persists for a long time. It will be followed at
least up to conjunction with the sun, and possibly recovered in
the autumn after that. Professor Barnard writes that he got
good measures on April 16th, 23rd and 25th; an observation
on May 2nd was doubtful owing to moonlight. The comet
was of magnitude 15 in .\pril, but is rapidlv getting fainter; its
diameter is about 10". On April 23rd at 14" 45"' 48"
Greenwich mean time, its right ascension was 9" 53™ 27°- 28,
South declination 7° 48' 23" -9. This was more than a year
after perihelion passage.

A query that appeared in " Knowledge" for April, page
135, asks how the distance of this comet from the sun and its

speed can be calculated at any time. There are probably a
sufficient number interested in this problem to justify its
discussion here. I deal with it only on the assumption of
elliptical motion, as the discussion of perturbations would
need too much space, t denotes the interval in days since the
perihelion passage of 1910, April 19-68. u is an auxiliary
angle known as the "eccentric anomaly." We must find it by
trial from the equation

?X0--012967 = H°-55°-4216 sin n

For example put ^ = 731 days, which brings us to 1912, April
19-68. The left hand side =9°-478. Trying in succession
40°, 50\ 57° for ;(, the right hand side becomes 4' -37, 7°-54,
10"- 52. Interpolating and making a few more trials we
obtain the correct value of ;(, viz.. 54° -721.

Next we find r, the distance from the Sun, bv the equation
r = 17-945 (1 - 0-96729 cos u).
Substituting 54'-721 for u, this becomes 7-9197, the unit being
the Earth's distance from the Sun. To bring to miles we
muhiply by 92,820,000.

The velocity expressed in units of the Earth's mean velocity is

V-

- -055726.

To reduce it to [uiles per second we multiply by 18-47.
In the present case we get 18-47 \ -252534 - -055726
log. 18-47 = 1-2665
log.- 196808 = 9-29404
half this = 9 - 64702
log. miles per second = 0-9135

Miles per second = 8-194.

M.^SSES OF STARS. — Professor Lowell has an article in
Piypnlnr Astronomy for May, on the masses of binary stars.
Grouping the results according to parallax, he finds the
resulting mass steadily increases with the distance. This is
discussed, and shown to indicate the unreliability of the
smaller parallaxes, r'-f of a second being determined as the
smallest that can be trusted. The following are the final
figures :

Limits of p:u-allax.

Above 0" - 4

0"-2 to0"-4

0-1 toO-2

0-067 to 0-1

0-033 to 0-067

0-017 to 0-033

0-007 to 0-017

This shows that for the best determined parallaxes the mass
of each component is very near that of the Sun. We have
good reason for thinking that there are stars (such as Aldebaran
and Arcturus) whose mass vastly exceeds the Sun's, but these
are probably exceptional. Professor Lowell altogether dis-
cusses twenty-six pairs, and his result tends to the conclusion
that the masses of the stars vary much less widely than their
lustre.

BOTANY.

By Professor F. Cavers, D.Sc, F.L.S.

FORMALDEHYDE AS FOOD FOR GREEN PLANTS.
— It has long been known that the first product in the making
of organic food by green plants, from the carbon dioxide and
water absorbed by their leaves and roots respectively, is
formaldehyde (CHjO), the starting-point for the formation
of carbohydrates and of higher compounds. Various experi-
menters have endea\oured to show that plants can utilise
formaldehyde as food material when presented to them, in

Mass of binarv (Sun = l).
1-93
1-77
1-33
1-43
1-95
3-46
33-43

229

230

KNOWLKDGi:.

June. \9\i.

the absence of a supply of carbon dioxide, but success has
only been obtained with simple freshwater Algae like
Spifogyra. Twenty years ago. Bokorny showed that though
formaldehyde is poisonous, even in ver\- dilute solutions, >et
a substance called oxyniethyl sodium sulphonate (easily broken
up into fornialdehj'de and sodium sulphitel can be used in
culture solutions, in the proportion of 1 per cent., without
injury to Spiro^yra.

Grafe [Bcr. d. deiitsch. hot. Gcs.. 1911) has now
experimented with the French Bean, and finds that seedlings
of this plant can make use of the vapour of formaldehyde.
He allowed the seedlings to germinate, removed their
cotyledons (containing reserve food), and placed them in
vessels exposed to light. In some cases, the seedlings
were supplied with air deprived of carbon dioxide, but con-
taining formaldehyde vapour. 1 he results showed that the
plants made use of the formaldehyde vapour, producing
abundant sugar in their leaves, and increased greatly in dry
weight, as compared with the control or comparison plants
not supplied with formaldehyde. Apparently, however, the
formaldehyde prevented the formation of starch from the
sugar.

A NEW FUNGUS IN THE BEET ROOT. — In the
course of his work on the disease of Sugar Beet caused by
Nematodes (round-worms), Nemec found a Fungus, belonging
to the Chytridiaceae, in the cortex of the lateral roots. He has
now {Ber. d. deutsch. hot. Ges.. 1911). given an account of
the structure and life history of this Fungus — a new genus
and species called Sorolpidiuin Bcfac. It belongs to the
Chytridium family, and therefore to the lowest forms of F^nngi.
1 1 appears in the cortex cells as a nucleated mass of protoplasm,
which grow s larger at the expense of the cell and finally nearly
fills it. Then the Fungus cell acquires a cell-wall, and its
contents divide into several uni-nucleate portions or sporangia.
Each sporangium then produces two. three, or four zoospores,
which escape, swim about, and infect other cells. In several
respects. Sorolpidimn resembles the Plasmodiophoraceae — the
group to which belongs the Fungus causing finger-and-toe
disease of the turnip. Nemec considers it as a link between
this group and the Chytridiaceae, and as indicating the close
relationship of the two groups.

LIFE HISTORY ol' ZANARDINIA. — The genera
Cntleria and Ziuiardiiiia. forming the small family
Cutleriaceae, are of great interest, because they form a
transition from the lower Brown Algae, in which the sexual
cells, if formed, are nearly or quite alike in size, to the higher
Brown Algae iDictyota and Fucks series) in which the female
cell is an oosphere, much larger than the male cell, and
differing from it in not being motile.

The life history of Cntleria has already been worked out in
some detail by various botanists, including Falkenberg.
Sauvageau and Church. The sexual and asexual plants are
very different, the former being an erect ribbon-like and much-
divided structure, while the latter is a flat creeping disc of
roughly circular outline. Before the connection between the
two forms was discovered, the asexual form was called
Aghjozoiiia, and was regarded as an entirely different plant.
Careful investigation has shown that Cntleria may be
regarded as consisting potentially of a basal disc, producing
spores, and an erect branching portion producing sexual cells.
The two portions require quite different conditions in order to
develop fully. In the Mediterranean, the Aglaozonia form
occurs in summer, and the Cntleria form in winter. In
England the reverse holds good. In the north, the Cntleria
form becomes more and more scarce, and the plant is repre-
sented by only the Aglaozonia form on the Scandinavian
coast. Conversely, in the south the Aglaozonia form becomes
rarer, and at Naples it is unknown, only the Cntleria form
being found there.

The life history of Cntleria is a good illustration of the
influence of external conditions on the course of development
of the reproductive cells. Normally, the fertilised Cntleria egg
produces an Aglaozonia plant, but this stage may be omitted,
and a Cntleria plant arise directlx'. The zoiispoies produced

by the Aglaozonia normally produce a Cntleria plant, and
this usually produces Aglaozonia discs from its base; the
Cntleria plant may undergo arrest of growth, leaving the
Aglaozonia to continue the life history. Northern conditions
favour the predominance of the asexual or Aglaozonia form,
while southern conditions favour that of the sexual or
Cntleria form.

Vamanouchi Uiot. Magazine. Tokyo. 1911) has worked out
the development of Zanardinia. which is allied to Cntleria.
but has a disc-like thallus only. The nuclear divisions of the
ordinary cells of the disc-like asexual plant show forty-four
cliromosomes ; the division of a zoospore mother-cell shows
reduction, so that the zoospore has twenty-two chromosomes.
The zoospore produces a disc-like sexual plant with twenty-
two chromosomes in the nuclei of its cells ; the fertilised egg
cell has forty-four chromosomes, and this number is present
in the asexual thallus to which it gives rise.

In Zanardinia. therefore, there is a regular alternation of
generations, exactly as in Dictyota. Polysiphonia and so on.
characterised by (1) different number of chromosomes in the
sexual and the asexual plants (2) one plant being asexual and the
other sexual. The asexual and sexual plants are exactly similar
in structure, apart irom the difference in the nuclei, just as is
the case in Dictyota and Polysiphonia.

MAI/E SUGAR.— Doby [Cheni. Zeitnng. 1910. page
1330) has investigated the different forms of Maize which are
grown in Europe, with a \iew to their productiveness in the
manufacture of sugar, cellulose and alcohol. Owing to its
intolerance of frost, or even of cold nights. M.iize is hardly
grown in England, except as green fodder, its stems being
sweet, owing to the presence of cane sugar. Even in the warmer
parts of Germany the amount of sugar in Maize is not so high
as in .America, but the culture of Maize nevertheless pays
well. The largest amount of sug.ar is obtained on removing
the young cob before the seeds have been allowed to ripen.
When the cob is removed the amount of sugar passing up the
stem increases until it reaches a maximum, when it diminishes
again owing to respiration taking place in the still growing
stem. The stems. leaves, and even the axis of the cob. afford
excellent material for the manufacture of paper; the unripe
cobs, as well as the green stems, can be used in the manu-
facture of alcohol.

THE NUCLEOPROTEINS.— A large amount of work
has been done in recent years, on the nucleoproteins of both
plants and animals. Much of this has been collected by
Brugsch and Schittenhelm in their text-book. "Die Nucleinstoft"-
wcchsel und seine Storungen " (1910). Plimmer ijonrnal
Chein. Soc vols. 93, 94) has indicated accurate methods for
the determination of the nucleoproteins according to the
quantity of phosphoric acid and the purin bases, which are the
results of the splitting of the nucleoproteins by hydrolysis.

The nucleoproteins differ from other proteins in consisting
of a protein combined with nucleic acid, the latter containing
phosphorus, and in their resistance to the action of enzymes
which readily decompose the primary proteins into peptones
and simpler nitrogenous substances. Being essential con-
stituents of the nuclei of plants and animals, they play
an important part in the physiology of the cell, for the
existence and development of which they are essential. The
embryonic and glandular cells of animals are rich in nuclear
material, and contain relatively large quantities of nucleo-
proteins. The same is the case with the embryonic cells of
plants, not only in embryos, but also in the embryonic
tissues and growing points of the stem. It is clear
that formation of nucleoprotein material must take place
during growth of the active tissues of plants, since increase in
amount of nuclear material precedes the division of the
nucleus.

Zaleski iBcc. d. dentscli. bot. (Jes.. 1911) has investigated,
by anal\sis. the changes in amoimt of nucleoproteins during
growth of certain plants, e.g., bean stems. lea\es, roots, onion
bulbs, seedlings. His results indicate that during growth

June, 1911.

KNOWLEDGE.

231

there is a steady increase in the amount of nucleoprotein
present in the plant. He deprecates the attempt made by
some writers to attribute to the nucleoproteins the qualities
of "life-bearers," "inheritance-bearers," and so on, and
points out that protoplasm is an e.\ceedingly complex
structure, made up of many protein substances, though
its complete chemical structure is quite unknown.

FURZE THORNS.— In 1893, Lothelier described experi-
ments on the influence of humidity and light on the
development of the leaves and branches of various spiny
plants (Furze, Barberry, and so on). He claimed that branches
of Furze, which under normal conditions are developed .as
thorns, tend to lose their spiny character and to produce
leafy branches. The results obtained by Lothelier were
criticised later by Goebel, who contended that the leafy
shoots obtained by Lotlielier were simply " reversionary
shoots," which can be produced at any time from ordinary
Furze branches when the plant is pruned. 2eidler {Flora,
1911) has made a series of careful experiments with
Furze plants raised from seed, and his results may be
thus summarised. ( 1 1 Spine formation is hindered in moist
atmosphere, also in feeble light — in total darkness seedlings as
well as older plants of Furze very quickly perish. 121 Typical
more or less flattened foliage-leaves, without spines, are
formed on the basal portions of the shoots, when plants are
grown in damp air, but these are only formed at the beginning
of each season's growth, and, moreover, they may occur on
plants grown under normal conditions, so that each year's
growth can easily be recognised on a plant. (3) Lothelier's
results were due to the fact that he did not use entire plants,
but cut portions, and besides he made no control experiments
which would have shown that leafy shoots may arise in cut
Furze stems grown under normal conditions.

FUNGUS IN LIVERWORTS.— Garjeanne, who has
already contributed greatly to our knowledge of the biology of
the " fungus servant " or mycorhiza present in various Liver-
worts, has recently {Flora. 1911) made an extensive re-investi-
gation of the subject. He shows that the infection of the
rhizoids 1" root-hairs ") of leafy Liverworts is a widely-spread
phenomenon, that different kinds of Fungi may enter into
partnership with the Liverworts in this way. that some of these
Fungi belong to the genus Miicor (to which belongs the
common Black Mould found on bread, and so on). In most
cases, the particular Fungus, on being isolated and cultivated,
proved to be Miicor rhizophihis. a new species, with small
gonidangia on a slightly-branched gonidiophore. It has a
greatly developed mycelium, with numerous transverse walls,
and produces several additional forms of spore besides the
gonidia.

THE EVOLUTION OF THE FLOWER.— H. F.
Wernham has commenced to publish, in the Ncu- Phytologist
(Vol. 10, No. 3. March, 1911), what promises to be one of the
most interesting of the various series of papers which have
appeared from time to time — in addition to the valuable
original memoirs and summaries of recent botanical research
— in this the youngest of British botanical journals, which has
already taken its place among the leading scientific periodicals
of the day. The author concludes his introductory article
with the following summary. (1) The fundamental guiding
principles in the progressive evolutionary history of the
Dicotyledonous flower are two in number, namely (i) economy
in production of the several items comprising reproductive
organs; (ii) progressive adaptation to the reception of insect
visitors. (2) The second of these principles compensates the
first for the decreased chance of pollination which the latter
involves. (3) There are also certain tendencies which subserve
these two main principles, the most widespread being (i)
progressively increasing conspicuonsness attained either {a) by
enlargement of the individual flower or, as is by far the more
general case {b) by excessive branching of the floral axes to
produce aggregation of the flowers into dense inflorescences ;
(ii) devices of floral structure or habit which ha\e obvious
relation to insect visits, the chief of these being zygomorphy,
which may occur either in solitary or loosely aggregated
flowers, but is illustrated more generally by the outer florets of

a close inflorescence ; (iii) fusion of parts, more particularly to
form tubes, the most important type of fusion being sympetaly
— the formation of a gamopetalous corolla. (4) The " primitive
flower " or prototype will be, of course, one in which the
working of these principles is realised the least. There will be
economy in production ; the parts will be, therefore, produced
in indefinite numbers, and there will be no gre:i: specialisation
for the reception of insect visitors — no aggregation, chorisis,
zygomorphy. or fusion of parts. An analogy to such a proto-
type is not wanting in the Gymnosperms. for we find it in cer-
tain members of the Bennettitales, and reflected in the typical
flowers of certain Ranalian orders, e.g., the Magnoliaceae.

CHEMISTRY.

By C. AiNswoRTH Mitchell, B.A. (Oxon.), F.I.C.

MUTTON BIRD OIL. — Numerous sea birds, including
the petrels and fulmars, contain a very high proportion of oil,
and for this reason are greatly valued by the natives upon the
Scottish Coasts, who obtain from them " oil for their lamps,
down for their beds, a delicacy for their table, a balm for their
wounds, and a medicine for their distemper." In the Island of
St. Kilda it is only legal to kill the fulmars during one week in
the year, but during that week from eighteen thousand to
twenty thousand birds are destroyed. So rich in oil are these
birds, that by passing a wick through their bodies they may
be used as lamps.

Hitherto the nature of the oil in these birds has not been
investigated, but in a recent issue of the Joiini. Soc. Cliein.
hid. (1911, XXX, 405), there is an interesting account by Mr.
Hewgill Smith of the characteristics of the oil of the Antarctic
petrel, the mutton bird {Aestralata lessoni), which during
the breeding season, is slaughtered in large quantities upon the
coasts of Tasmania and New Zealand. The " oil " of this
bird, which has now become a comniercial product, is carried
in the stomach, whence it can be ejected through the nostrils
as a means of defence against its enemies.

This oil, which is found in the stomach of the dead bird, is a
pale yellow or bright red liquid with a faint fishy odour.
When cooled to 0° C. it solidifies to a transparent mass. The
specimen examined by Mr. Smith had a specific gravity of
0-8819 to 0-8S58 at 15^ C. and absorbed 71 per cent, of
iodine. It contained a high proportion (36-9 per cent.) of
unsaponifiable alcohols, and, unlike the majority of animal fats
and oils, contained no glycerine. In its general composition
and properties it closely resembled .\rctic sperm oil and, like
that oil, did not thicken when exposed to the air. It would
thus be useful as a lubricant, if it could be obtained in
sufficient quantity, which is, however, unlikely. The body fat
of the bird was of quite a different character from this oil, being
a soft brownish solid with a specific gravity of 0-9351 to
0-9380, an iodine absorption value of 89- 1, and containing only
1 - 76 to 2 per cent, of unsaponifiable matter. This appeared
to be an ordinary fat, whereas the " oil " might be classed
with sperm oil among the liquid waxes. It has been suggested
that the mutton bird uses the oil for feeding its young.

THE DETECTION OF COCAINE.— A test for cocaine
has been based upon the fact that it combines with potassium
permanganate to form pink crystals in the form of nearly
square plates. This test has been studied by Mr. E. H.
Hankin (Analyst, 1911, XXXVI. 1), who renders it much more
sensitive by allowing a strong solution of permanganate to
evaporate on a glass shde. and then adding a drop of a
solution of alum containing the cocaine, and watching the
crystallisation under the microscope. The use of the alum is
to retard the action of the permanganate, and in this way it is
possible to distinguish between cocaine and certain other allied
anaesthetic compounds. As an illustration of the delicacy of
the test. Mr. Hankin cites an instance where a man suspected
of illicit dealing in cocaine had received timely warning of
the visit of the police. No cocaine was found, but various
pieces of paper, in which it was supposed that the drug had
been wrapped were subjected to the permanganate test, and
in the case of ten out of eleven pieces the characteristic
cocaine crystals were seen to develop. In another case a

232

KNOWLEDGE.

June, Mil.

.^tain upon a telegraph form, which was supposed to ha%'e been
produced by the saliva of a person who had taken cocaine
was examined in the same way, and here, too, an unmistakable
reaction was obtained.

ACTION OF STEAM UPON CARBON AND LIMK,—
The possible mode of formation of marsh gas and other
natural gases rich in methane is suggested by the results of
experiments made by M. L, \Mgnon (Comptcs Rcndiis. 1911,
CLII, 871) upon the action of steam upon a mixture of carbon
and lime. It was found that the steam was decomposed more
rapidly and at a lower temperature bj- a mixture of car-
bonaceous substances and lime than by the carbon alone.
Thus when the steam was conducted through the mixture
contained in a porcelain tube heated to about 600' to 800' C,
the resulting gas was found to contain hydrogen, methane,
carbon monoxide, oxygen, and nitrogen, the proportions
depending upon various factors such as the quantity of
steam present, and the duration of contact between the
excess of steam and the methane formed, more or less
decomposition taking place in accordance with the equaticm —

CH4 + HoO = CO + 3H,
Thus tw-enty-eight per cent, of methane was produced by the
passage of five grammes of steam during thirty-five minutes,
whereas only about eight per cent, was obtained after the
passage of fifteen grammes of steam during two hours. By
regenerating the lime from the calcium carbonate produced it
was found possible to transform the whole of the organic
substances present into hydrocarbons in the following manner

2C + CaO + 2H,0 = CaCO^ + CH4
and CaCO, = CaO + CO.

or combining the two equations —

2C + 2HoO = CO, + CH4
Since the methane requires a lower temperature for its
formation than that of the decomposition of the calcium
carbonate, the two gases may be collected separately.

It is suggested that these experiments also throw light upon
the formation of petroleum deposits. When animal and
vegetable remains are left in contact with water in the
presence of calcareous deposits, hydrocarbons are produced,
and it is quite possible that these, under the influence of
various physical conditions of pressure, and so on, have been
transformed into petroleum compounds.

GEOLOGY,

By Russell F. Gwixxell, B.Sc, A.R.C.S., F.G.S.

CARBON IN COLD ORE.— The well-known auriferous
conglomerates of the Witwatersrand, known as " banket,"
consist of beds of coarse well-rolled quartz pebbles,
together with smaller pebbles, the whole being cemented
into a compact rock by means of secondary silica.
They are obviously shore deposits, and are of very great —
perhaps pre-Cambrian-age. The gold occurs in the matrix
and not in the pebbles themselves. Pyrites is conimonlv
present, and also in places, carbonaceous or graphitic matter.
As the origin of the gold appears to be intimately related to
that of the other "impurities," it is a matter of considerable
interest to determine the source of the carbon. This latter has
been regarded as organic matter which directly precipitated
the gold from solution, although this seems hardly likely in
face of the fact th.at there is neither gold nor carbon in the
finer sediments which are associated with the b.anket. For a
fine sediment is naturally expected to yield organic matter in
greater abundance than does a coarse conglomerate. Writing
in the Transactions of the Geological Society of Soiitli
Africa (Vol, ,\III., 1910), on "The Mode of Occurrence and
Genesis of the Carbon in the Rand Bankets," Mr, C, Baring
Horwood shows that from its mode of occurrence the carbon
is of later date than the bankets, and is of inorganic origin.
Gold can be found not only as a film on the particles of carbon,
but also actually embedded in the latter. The carbon occurs
frequently in small irregular spheroids sometimes actually

replacing the quartz, and it is almost invariably closely
associated with pyrites when the latter is present. Further-
more, it occurs chiefly along and on both faces of partings in
the banket and along planes obli(jue to the bedding. These
facts cannot well be accounted for by any theory of organic
origin. Indeed the mode of occurrence of the carbon strongly
recalls the crystals of tourmaline of pneumatolytic origin, found
on the surface of joint planes in the red granite of the Bushveld.
The author's researches lead to the conclusion that the carbon
is of deep-seated origin and owes its presence in the bankets
to associated igneous magma, probably through the agency of
pneumatolysis. Other authors have ascribed an inorganic
origin to certain petroleums, and have included both graphite
and diamond as the end products of the petroleum series.
Now, great diabase dykes penetrate the Rand country, and to
these one would naturally look for the source of the carbon
(and incidentally of the gold). Analyses shew that carbon is
distributed evenly throughout the igneous rock, which would
hardly be the case if it were derived from organic fragments
caught up and enclosed in the molten magma at the time of
its intrusion. The fact that gold is not found, as is the carbon,
distributed about equally in dyke-rock and in banket is easily
accounted for by its relatively greater solubility. On this
account, subse(iuent leaching-out of the gold has removed it
from the dyke-rock. Summarily, the study of the carbon in
those mines of the Rand where it is most typically developed
certainly shows that its occurrence is closely associated with
that of the pyrites and gold, and indicates a close relationship
between its presence and that of neighbouring igneous rocks
which contain carbon. The occurrence of the carbon in tiny
spheroids scattered through the matrix of the bankets points
to deposition from gaseous or very mobile liquid hydrocarbons,
before the final cementation and induration of the bankets by
the deposition of secondary silica. Taken in conjunction with
the known facts of its occurrence in other parts of the world,
it is reasonable to attribute its origin to magmatic vapours
or solutions derived from the neighbouring basic igneous
intrusions before their final consolidation.

LABRAHOK, A LAND OF PROMISE.— In the
Oeograpliical Journal for April, Dr. Wilfred T. Grenfell
sings the praises of Labrador after an acquaintance with it
of twenty years. The country has been greatly neglected up
to the present time and little knowledge exists of its resources
beyond its coastal portion. Vet the author is confident that
Labrador can and will carry, in the days to come, a population
as easily as Norway does to-day. It is a better country by
far than Iceland, and until the wizard hand of man was
turned to New Mexico, Arizona or even to parts of Egypt
and West Australia it was able to offer as good attractions to
settlement as any of them, " If ever a race shall rise to
people her glorious fjords and inlets, and to wrest her
undoubted wealth from her forests and mines, she will, like all
northern countries, evolve a people endowed with those
sterling physical qualities that characterised the Vikings of
old." The agricultural outlook of Labrador is not hopeful
owing to the fact that the super-incumbent rocks have been
removed by glaciation from the .Archaean floor, which is thus
laid bare over much of the country. On the other hand this
fact need not injure the prospects of the development of
mineral resources. While very little serious geological work
has been done, the deductions of the few prospectors who
have visited the country show every possibility of valuable
mineral deposits. The inland resources are almost unknown,
but near the coast several deposits of economic value have
been found, and in some cases worked ; among these are
alluvial gold, antimony, mica, copper, iron pyrites and garnet.
Coal which may be a continuation of the seams of Cape Breton,
has been partially prospected. Finally, the beautiful
plagioclase felspar Labradorite, which derives its name from
the country and which exhibits an iridescent play of colours,
has been worked in an island near Nain, which consists
almost entirely of this mineral.

AN IGNEOUS COMPLE.X AND ITS ORIGIN.- A
number of instances are now known of igneous rock-masses

June. 1911.

KNOWLEDGE.

233

within which are found a series of different rock-types
arranged in a concentric manner. In some of these cases,
on the ground of field evidence, the occurrence has been
considered as a laccolith within which subsequent differen-
tiation has produced the concentric complex ; in others they
have been held to be stocks, or volcanic necks, in which
differentiation has occurred, sometimes with subsequent move-
ment of the differentiated bodies of magma. In the .4)Hc';-/t(r«
Journal of Science for .April. L. V. Pirsson and W. North
Kice describe a case which appears to be a laccolith, intruded
■between a granitic bathylith and a cover of mica schist.
This is Tripyramid Mountain in Xew- Hampshire, a roughlv
oval mass, rising about two thousand feet above the floor of
the neighbouring valleys, .\roand an inner core of syenite
occurs a medium grained inomonite which is succeeded
below and outwardly by coarse-grained gabhro. Lampro-
phyre dykes (regarded as complementary to the syenite-aplite)
are situated in the peripheral gabbro and in the granite
against which the comple.x abuts. .\11 the rock-types in the
complex possess a parting or sheet-jointing parallel to a dome-
surface, but there is a sharp transition-line between the
different types and only slight endomorphic evidence of
contact. As to the mode of origin of the comple.x, the
authors do not consider the case as similar to that of
Magnet Cove, Arkansas, which Marker has explained as being
due to the doming and erosion of superposed sheets, succes-
sively injected. The common jointing is not in favour of this,
nor the relative textures of the rock types, for this view would
make the gabbro, which is the coarsest grained variety, the
uppermost sheet. The suggestion that zonal arrangement of
different rock-types in an intrusion may be due to absorption
and assimilation of surrounding country-rock is equallv
inapplicable in the present case. For while the country
rocks (granite and mica schist) are decidedly acid in character,
the border facies of the complex is the basic gabbro, the
intrusion becoming more acid towards the centre.

While the concentric arrangement of the complex natur.illy
suggests a differentiation of a body of magma in place, the
abrupt transition of one type into another, and the occurrence
of syenite dykes in the monzonite. and probably of monzonite
dykes in the gabbro. negative this conclusion, the dykes
suggesting a series of successive intrusions. .Apparently what
best explains the phenomena at Tripyramid Mountain is a
process of intermediate nature, in which both differentiation
and repeated intrusions, separated by only short intervals,
took place.

METEOROLOGY.

By JOH.N A. Curtis. F.R.Met.Soc.

The Weekly Weather Reports issued by the Meteorological
Office show that during the week ended .April 22nd the air
temperature was in excess of the average in all districts, by as
much as 4" -9 in England, N.E. and E. The extreme maxima
varied from 59° in Scotland X. lat Strathpeffer) to 69' in Eng-
land E. (at Cambridge), while the minimum fell to 27° at West
Linton and to 28° in the Shetlands and at Wick. Even as far
South as Swarraton in Hampshire a temperature of 30° was
reported. In the English Channel the lowest reading was 40 .
On the ground much lower temperatures were, as usual,
experienced, and at Crathes the reading was as low as 20°, at
Balmoral Zi°.

Rainfall was in defect in the East and South of England,
but elsewhere was in excess. In Scotland N. the amount
collected was three times as much as usual, and in Ireland it
was twice as much. In England E. and S.E., however, the
fall was very slight and at many stations the week was
rainless. As a rule sunshine was less than usual. The
sunniest places were Felixstowe (60-6 hours, 63%) and
(iuernsey (61-9 hours, 55%), while Valencia had only 5-7
hours (6%). At Westminster the total duration of sunshine
was 39-7 hours (41'7„).

The mean temperature of the sea water round the coasts
varied from 49° -9 at Seafield to 40' -2 at Cromarty.

The week ended April 29th, was warm but cloudy and

unsettled, with thunderstorms and hail. The temperature was
above the average in all districts, the greatest excess being in
England E., where it was 4°- 6 higher than usual. The highest
maximum, however, was 2^' lower than that of the previous
week, being 67° (at Cirencester) on the 23rd, as against 69°
(at Cambridge) on the 22nd. The lowest readings were 28'
at Balmoral and 30° at Nairn, but at no other stations in the
United Kingdom did the air temperature fall below the
freezing point. On the ground the temperature fell to 23" at
Crathes, and to 25" at Balmoral.

Rainfall was in excess in all parts. .At several stations
rain was measured on e\-ery day. .At Donaghadee, on the
29th, there was a heavy thunderstorm wdth rain and hail, the
total precipitation for the day being 1-12 inches.

Sunshine was everywhere deficient, and in some places less
than half the usual amount was recorded. Toniuay reported
the largest aggregate, 48-5 hours (49";,). At Westminster the
total was 35-3 hours (35%).

The mean temperature of the sea water ranged from 40 • 7
at Cromarty to 50' -8 at Seafield.

The week ended May 6th was unsettled at first but the
weather improved later.

Temperature was low in most places, although the defect
was nowhere very great. The highest reading reported was
56° at .Alnwick Castle and at Raunds. Frost w-as experienced
in several places, the lowest readings being 28° at West
Linton, and 29° at Fort Augustus. The grass thermometer
went down to 23" at Crathes, and to 24' at Burnley.

Rainfall was again in excess, except in England N.E. and E.,
where it was slightly in defect, and in the Midlands, where it
was almost normal. In Scotland and in Ireland the rainfall was
very heavy, and at Fort William the total for the week was as
much as 3-27 inches, and at Killarney 2-34 inches.

Sunshine was above the a\erage in England E. and S.E.,
and in the Midlands, though below it elsewhere, except in
Scotland N.. where, in spite of the fact that the rainfall was
nearly twice as much as usual, the sunshine was 5 hours (5%)
in excess of the normal. Brighton reported the longest
duration of sunshine, 58-4 hours (57%) : at Westminster,
the amount was 45-5 hours (45%).

The temperature of the sea water varied from 43° at
Pennan Bay and Burnmouth to 54° at Seafield.

The week ended May 13th was fine at first, but became
changeable and thundery. Temperature was high throughout,
being in excess of the average in all districts. In Scotland
W. it was 6°-2 above the normal. Maxima above 70° were
recorded in all parts, the highest being 76 at Colmonell and
Greenwich. No frost was experienced, the lowest of the
minima being 5i°, which was reported from Geldeston Bawtrey
and Marlborough. The lowest temperatures on the grass were
27" at Kew and at Rauceby, and 28° at Greenwich. Tunbridge
Wells and Wisley.

Rainfall varied a good deal in different parts of the country.
It was a little above the average in Scotland, and in Ireland
N., but was below elsewhere, and in some places very greatly
below. In the Midlands it was only one-third, and in the
English Channel, less than one-seventh of the usual amount.
Some heavy falls were however experienced, especially during
the thunderstorm on the 13th, when the rain collected at
York and at Rothamsted measured 1 • 2 inches, at Killarney
1-4 inches, and at Newton Rigg and Burnley 1-7 inches.

Sunshine was generally above the average. England S.E.
was the sunniest district, with 68 hours (65%), or 21 hours
above the normal. Of the individual stations. Felixstowe
reported the largest aggregate 89-7 hours (85%), and Hastings
the next Largest, 82-7 hours (79%). .At Harrogate the total
duration was only 32 • 1 hours (30%). At Westminster the total
was 52-5 hours (50%i).

The temperature of the sea water was higher on all coasts
than during the corresponding week of 1910. The individual
readings varied from 44' at Burnmouth. to 60° at Seafield.

A balloon carrying a Meteorograph was liberated at
Manchester at 5.50 p.m. on March 1st and was found at Little
Downham, near Littleport, Cambridgeshire, having tra\elled
one lumdred and twenty-four miles in a south-easterlv direction

234

KNOWLEDGE.

June. 1911.

The instrumental record showed that the balloon had
reached an altitude of 19-1 kilometres or sixty-two thousand
feet. The lowest temperature recorded was 214°- 5 (absolute
scale) at a height of thirty-three thousand feet. The
temperature then increased to 224^-5 at thirty-nine thousand
feet, but fell again to 21S°-0 at the maxinumi height.

By

MICROSCOPY.

A. W. Shepp.-\rd, F.R.M.S.,

with the assistitiicc of tlic folloic'ing inicroscopists :-

AUIML'R C. HANFItMJ-

Thk Rkv. E. W". tJ<.)\i'KLL. M..\.

jAMtb BlRTON.

Charles H. Cakfvn.

C. D. Soar, F.R.M.S.

.■\RTHLR EaRLAMi. E.R.M.S.

Richard T. I.hwt!,. F.R.M.S.
Chas. F. Rolssklkt, F.R.M.S
D. J.ScoiRHELD. F.Z.S., F.R.M.S.

Figure 1.
Nc!iiJi(7iiia tn\niiiii!aris. Female, ventral surface.

NOTE ON A \VAT1:K-MITE NEW To BRITAIN
iXEUMANIA TRIANGULARIS PIEKSK',).— In 1908
both sexes of the above mite were taken from a fresh-
water pool in the locality of Stourbridge, Worcestershire.

The female is 1-42 millimetres long, of a pale yellow colour.
Epimeral plates are finely granulated, the fourth pair having
a well-marked hook-shaped process at their lower extremity.
The genital plates are green in colour, with thirty to thirty-
five acetabula on each, .\bove each plate are three small hair
pores arranged somewhat like the apices of a triangle in outline,
together with a prominent gland. Legs are yellowish-green
in colour and all supplied with strong spines or swimming
hairs, the second and fourth pairs having in addition a number
of feathered or serrated hairs presenting a pretty effect under
dark ground illumination.

The male is smaller than the female, 1-12 millimetres long, of
a light .almost transparent yellow colour. The Malpighian \ essel
is very distinct. Genital plates are circular in outline, of a pale
green colour, with about twenty-five acetabula on each half and
several fine hairs at top and bottom. Two prominent glands
on each side of median line, one towards margin of body.
Several species of this genus are described by Mr, C, D. Soar in
Scicticc Gossip, Vol. \'II. p. 19 under the generic name

Cochlcoplionis.

G. P. Deklev,

UN THE 1D1:NTITV OF HABROTROCHA BIDHXS
(GOSSE), — If the recognition of this handsome and graceful
Bdelloid depended solely upon the original description
("Catalogue of Rotifera found in Britain," P, H, Gosse, Ann.
and Mag. Nat. Hist., 1.S51I, it could only be regarded as
hopeless, for the few characters then stated liave proved to
be common to many distinct forms,-- Fortunately, however,
Gosse found opportunity in "The Rotifera" (Hudson and
Gosse, 18S6), to provide a fuller description accompanied by

figures which, if wanting in detail, give a fair idea of the
general style of an animal which seems to be somewhat of a
rarity. In about twenty years' experience I have only met with
it on two occasions, vi^. : in ground moss kindly collected for
me by Mr. D. J. Scourfield near Bury St. Edmunds, and from
roof moss which I obtained from an accessible roof-gutter
near Mundesley,

But before finding, in 1908, the particular form which I am
confident is that seen by Gosse, I had repeatedly compared
with his description other two-toothed blind Philodinidae,
always with unsatisfactory result. That others may avoid
the like tedious proceeding, it may be useful to point out the
more distinctive details suppHcd by Gosse, and to give some
additional characteristics which will further establish a very
interesting species.

The corona and the body outline of my specimens were
generally in agreement with Gosse's figures, and they also
possessed the wild manners, the small two-toothed rami, and
(occasionally) the angular lateral prominence which he
described. But the most unusual detail, and. therefore, the
best for purposes of identification, was the constantly
recurring display of the central toe. short and acute, between
the spurs, as shown by Gosse in his figure of the imperfectly
retracted position, a pose of the toe and spurs characteristic
also of Habrotrocha tripiis (Murray I. but elsewhere unknown
among blind three-toed Philodinidae. Gosse describes the
foot as having a small stiff point behind and two soft

Figure 1,
Head with corona (dorsal view).

ce

Figure 2.

Extremity of foot
(ventral view).

5_ l/V\'^

/

CE

Figure 3.

Anal segment

and foot
(dorsal view).

cylindrical lateral protrusible toes, truncate at the extremities.
I do not seem to have seen the truncate ends of the lateral
toes, but the central toe was frequently visible as a small stiff
point behind,

Gosse's description of the stomach is also noteworthy. In
one of his specimens it ;ippeared to be composed of a number
of spherical cells, but in others was of a minutely granular
texture. These varying appearances of the stomach are quite
usual with several species of the "pellet-making" Philodinidae
and depend upon the quantity of digestive fluid between the
two membranes of the stomach wall. When the fluid is scanty
the food-pellets within the stomach cavity are plainly visible,
■and have the appearance of spherical cells. When the fluid is
abundant, its finely-granular consistence is sufficiently opaque
to completely hide the actual contents of the stomach, I
believe, therefore, that Gosse's description of the stomach
indicates that his species was a pellet-maker and in this
respect .also my specimens agreed with his, Habrotrocha

June, 1911.

KNOWLEDGE.

235

hidciis is, in fact, the largest pellet-making species yet found,
my exatnples attaining a length of 460 m, when apparently
fully grown. But apart from its great size, it may be
recognised by the slenderness of the anal segment, and by the
length of the foot, the post-anal segment being about twice
as long as its average width, and also by a pecuHar ridge-like
structure crossing the trochal discs. When feeding the foot
was generally extended, sometimes showing the central toe
(c.t. Figures 2 and 3), sometimes not. The rather short spurs
(s.s.) were held nearly parallel to the body axis. The lateral
toes \l.t.) were invaginated as usual.

A diagrammatic view of the head with corona displayed is
given in Figure 1, the cilia of both principal and secondary
wreaths, which are quite normal, being omitted for greater
clearness. The moderately wide trochal discs are supported
on two strong pedicels. Near the centre of each disc the
trochal seta-pencil rises from a small prominence from which
a low ridge (r. r.) continues to and over the inner margin of
the disc, the ridge from either disc dipping to meet that from
the other. As these ridges arise at the nerve centre of the
discs, I surmise that they protect nerve branches passing
towards the median line. I have not seen them so well
developed in any other Bdelloid and rarely even rudimentary.
Between their junction and the moderately high upper lip
(i(./.) is visible a fleshy nexus in.) connecting the pedicels
and extending nearly up to the level of the discs.

In all my specimens, the food- pellets were of unusually small
size. The characteristic wildness of the animal is greatly
modified if it be kept for a week or so in a small trough or cell.
Examples thus confined produced eggs of oval form, but
proportionally longer than customary among Bdelloids. The
embryo developed very rapidly, and the young rotifer emerged
in about six days, about half the usual period.

David Brvck.

ON FLUID MOUNTING.— There is no question that
with very many classes of objects fluid mounting is the best,
as the preparation is shown without pressure or distortion, and
the natural arrangement of the parts gives a true idea of its
real nature. Many of us, however, bar fluid slides altogether
owing to their usual habit of leaking after a short period, and
it is to obviate this fault that the present note is given. The
first essential of a cemented joint is usually as close a joint as
possible with a mininnnn quantity of the adhesive. This, as
is ordinarily tried with marine glue, gi\es a perfectly sound
joint of the ring to the slide, but owing to the unequal expansion
and contraction with temperature changes of the fluid mountant
as compared with the glass, the rigid setting sooner or later
gives way and the slide is ruined. What is really re(|uired is
a cement sufficiently hard to be adhesive, rigid enough to bear
handling, yet elastic to stand the trifling differences of volume
required with temperature variation. Hence a sufficient
quantity of an elastic cement must be used to accommodate
by its own variability the necessary changes. Such a cement
can be made as follows : — A penny tube of cycle rubber
solution, which is rubber in naphtha, is emptied into a four-
ounce bottle and double its volume of old gold size added,
shaking till thoroughly mixed. This must now be placed on a
water bath or anywhere to be heated not beyond one hundred
and fifty degrees in order to drive off the naphtha and .any
volatile constituent of the gold size. Whilst this is being done,
prepare a thick solution of shellac in absolute alcohol (not
methylated spirit) and add, when the other solution is naphtha-
free, twice its volume of shellac solution as thick as treacle. Stir
whilst hot and filter through fine nuislin before cooling. It can
be thinned as desired with absolute alcohol. The reason why
methylated spirit cannot be used is that the denaturant which
evaporates with the spirit may evaporate inwards and be
condensed in the fluid mountant, and I have seen many slides
spoiled by a milky fog caused by the condensed denaturant,
which is not transparent w hen mixed with water any more
than methylated spirit is. The quantity required is not large,
so absolute alcohol is not prohibitive.

Use the mountant as thickly as it can be worked to flow and
make a heavy ring on the slide. Of course, it is preferable to
do a fair quantity at one time. This sets in about fifteen

minutes and dries reasonably hard in a day. This ensures
perfect contact of the cement to glass slip. To cement the
rings I take a scraping of soap from the piece in use, and
spread it on the turntabf? centre. A ring flatted on coarse emery
cloth if metal, or coarse saiidpaper if vulcanite, can be pressed
on to the soap and adjusted centrally with sufficient firmness
to be cemented all round, leaving a more le\ el ring than can
be otherwise obtained. The next day, or later, a thin ring of
cement can be put on the slip and the ring adjusted in place.
When hardened you will have perfect .contact of cement and
glass, with perfect contact of cement and ring, with an elastic
layer of cement in between, which is capable of absorbing
any small variation under the exercise of pressure. .A. ring
fixed in this manner is likely to remain permanent if the further
mounting operations are properly performed.

C. E. Heath, F.R.M.S.

MICRO -FUNGUS FROM THE JAPAN - BRITISH
EXHIBITION. — A friend who visited the .\ino village in
the Japan-British Exhibition last year at Shepherd's Bush,
happened to pull out a straw from one of the native huts.
He found it was rice straw and had been brought from Japan
specially for the construction of the huts. Some minute dark
spots on a leaf proved on examination under the microscope
to be patches of a fungus. It is one of the Puccinias, a genus

Figure 1.

Figure 2.

of which there are very many species, growing on various
plants and widely distributed. Dr. Cooke records no less
than seventy-eight for Britain alone, " Microscopic Fungi "
p.p. 202-212. The well-known " Mildew " on wheat is one
of them, P. grant inis, and the example found on the rice straw
closely resembles it, though probably, as living on another host,
it would be considered a separate species. The patches (sori)
are found on both sides of the leaf in this case, and are made
up of very numerous double spores, attached to stalks often of
considerable length. Figure 1. The mature spore has a thick
outer coat of a rich brown colour, and a thinner one within.
.\i the apex an opening through the thick coat can be seen,
and the lower spore has a similar opening — usually rather
difficult to make out — on one side just below the cross wall.
Figure 2. Through these openings, on germination taking
place, a tube is protruded, the further end of which divides
into three or four cells each bearing a very small spore on the
end of a short branch. Figure 2. It is these extremely minute
secondary spores which propagate the fungus. In many
species they do not reproduce a Puccinia such as they arise
from, but another form known as " cluster cups," an elegant
little fungus well known to microscopists. This may be pro-
duced on the same or on a different species of host plant, witfi
many variations in the details, for the life history in most cases
is very complicated. Immense loss is caused to farmers and
horticulturists, as the fungi weaken and even destroy the plants
on which they grow. . „

THE SCALES OF LEPIDOPTERA.— Some time ago I
recei\'ed from a correspondent in South Africa some curious
pupae which he had found suspended by threads from one of
the branches of a bush. They were sent in spirit which did
not seem to have injuriously affected either their form or
colour. On examination they were seen to be in different
stages of development, the imago in one being apparently on
the point of emergence. Upon carefully removing the
enclosing membrane from this, I extracted a butterfly which

236

KNOWLEDGE.

June, IQll.

appeared to be perfectly mature, except that the wings were
shorter than the body, as is usual when the insect first bursts
from the pupa case. It had often been a matter of conjecture
how it was that when the wings of a butterfly were fully
expanded a few hours after emergence, the scales were all
perfectly formed and covered the entire wing surface by over-
lapping at their lower edges like tiles when laid on the roof of
a house. It did not seem possible that if the scales were
fully formed an5 covered the wings in the same manner when
only one third of their ultimate length, they could also cover
the expanded wing so completely as we find to be the case in
the mature insect. On setting the specimen referred to, and
placing it under the microscope, the mystery was at once
sohed by finding that the scales were all there and in perfect
condition, but instead of lying fiat they were standing on end
attached to the membrane of the wing in the usual manner,
but so close together that the coloured pattern formed by them
could be distinctly made out. In this position, — just as
roofing tiles take up less room when standing close together on
edge, — the scales then occupied a niinimum amount of space,
and it seemed clear that as the membrane expanded it would
draw their stalks farther apart, and at the same time cause
them to lie down, and in this way cover a greatly increased

^^"^^^ . . R. T. Lewis. F.K.M.S.

THE ROYAL MICROSCOPICAL SOCIETY.— April
19th. H. G. Plimnier. Esq., F.R.S., President, in the chair.
Mr. E. J. Spitta gave a demonstration of low-power photo-
micrography with special reference to colouring methods,
in which he showed some fifty coloured slides which had
been coloured by an artist friend by a completely new method.

Mr. Spitta also communicated a report on Grayson's
Rulings presented by Mr. Conrad Beck to the Royal Micro-
scopical Society, which embodied the results of many thousand
observations.

Mr. E. J. Shepherd read a paper on "The Re-appearance
of the Nucleolus in Mitosis," which formed an addendum to
his previous paper, communicated in April, 1909, on "The
Disappearance of the Nucleolus in Mitosis." In the present
connnanication he said that with a view to ascertaining how
and when the nucleolus makes its re-appearance, the diaster
stage is the one which calls for most careful study and
observation. At or about the time of the formation of the
dispirem, and before the diasters have lost their characteristic
shape, a looping in the chromatin is observed — the number of
loops varying in each daughter nucleus. It is in these loops
that the nucleoli will appear, but it must not be inferred that
a nucleolus will appear in each loop, as there are frequently
more loops than nucleoli. The latter make their appear-
ance when the division of the cell is well marked, and
when the interzonal fibres have generally disappeared.
From the results of his research, he was of opinion that the
nucleolus is a product of the chromatin injected into the loops
by a process which can best be described as a "streaming in "
process. A full account of the technique of the staining and
methods adopted, and so on, which have led to the above
conclusion, will be found in the Jniinia! of the Royal
Microscopical Society.

Mr. J. Murray communicated the second portion of a report
from the Shackleton Antarctic Expedition of 1909, on the
Canadian Rotifera. Forty-two species (all Bdelloids) were
collected among mosses. They included five new species —
Calliditia aspcnila, C. canadensis, Mniobia obtiisicornis,
M. inonfiiiiu. Habrotrocha inaculata. There were also a
number of peculiar varieties of other species. C. aspentla
has since been found in Ireland by the Clare Island Survey.
Twenty-seven Bdelloids were previously recorded for the
United States. Six of these occurred in their collections, so
that the number of Bdelloids now known in North .America
stands at sixty-three species, but a number of these are of
doubtful value. .Among the rarer Canadian species were
I'liilodina austral is (.•\ustralia and Canada), Callidina
speciosii (British Guiana and Canadal. C. zickendrahti
(Russia and Canada).

.A description of a new piece of apparatus for photomicro-
graphy, with the microscope in the inclined position by Sefior
Domingo de Oureta, was read by the Secretary.

OUEKETT MICR(JSCOPICAL CLUB. — April _',Sth.
1911. Professor E. A. Minchin, M.A.. F.R.S., President, in
the chair. Dr. .\. C. Coles, of Bournemouth, sent a note
describing the advantages of Parolein as a mounting medium.
Its refractive index is 1-471, as against 1 -530 for balsam in
xylol. It is absolutely neutral, and. so far as is known at
present, is entirely without action on any dyes. It is rather
more trouble to use than a balsam, as, being a liquid, the
preparations require to be ringed with some cement which is
also neutral. (A detailed account of the methods employed
by the author will be found in The Lancet for April 1st,
1911.) A number of bacterial preparations mounted in
parolein were exhibited under microscopes lent by Messrs.
H. F. Angus & Co.

The President exhibilinl and described: (1) Cysticercoid
of the rat-tapeworm Hynienolcpis diminnta from the
body-cavity of the rat-flea, Ceratopliylliis fasciatns, with
head invaginated. (2) The same, with head extended.
(3) Another species of cysticercoid, probably H. miiriiia. also
from the body-cavity of the rat-flea. (4) Ventral nervous
system of C. fasciatits. (5) Salivary gland and duct of
C. fasciatns. These preparations were displayed under
microscopes, also kindly lent by Messrs. H. F. .Angus & Co.

The Honorary Treasurer. Mr. F". J. Perks, read "Some Notes
upon Seeds as Micro-Objects " contributed by Mr. N. F,. Brown.
It was reconnnended that the specimens be mounted in cells, dry,
on clear glass slips, not on a dark ground, and fixed in position
with seccotine or gum. For illuminating, a spot lens and
concave mirror below the stage, together with a stand
condenser to give top light, were used. Added beauty is
obtained if coloured gelatine, say red, is placed below the
spot-lens, and a green gelatine held over the stand-condenser.
Some of the more beautiful varieties w-ere then described,
among which may be mentioned Pterospernia andrunicdea,
Paiiloxoiia iniperialis. Philydrnni lanuginosnm, Nemesia
StriDuosa, Elioinirus elegans, and Sesantum capense.

Mr. D. J. Scourfield. F.Z.S., F.R.M.S., made some remarks
on " The LIse of the Centrifuge in Pond-Life Work." He had
recently been experimenting with a hand-driven form running
at about seven thousand revolutions per minute. The tubes
held only about one-and-a -half c.c. instead of the usual fifteen c.c.
It was found that if plain water be taken from any pond in a tube
without a net. and centrifuged, there are obtained numbers of
very minute flagellates, very small heliozoa, diatoms and
desmids, and a great variety of immature forms. The size of
these organisms was of the order of the one-thousandth of an
inch (25m). There was a considerable field for work on what
had been christened the " centrifuged plankton." He had
observed quite a number of forms new to him. but could not
yet say if they were really new. Certainly some of them had
never been named.

ORNITHOLOGY.

By Hugh Boyd Watt, M.B.(.).U.

JUDGMENTS ON THE KOOK. — Mr. Walter E.
CoUinge has recently been investigating the feeding habits of
the rook, and gives his finding in his First Report on
Economic Biology (Birmingham, Midland Educational Coy.,
1911. Price 2, 6 net.) He is strongly of opinion that we have
too many rooks, as they are distinctly destructive to cereal
and root crops, game, and so on, and that they should be
systematically reduced in number and held in check. This
verdict is supported by the results obtained from examination
of the stomach contents of eight hundred and thirty rooks
shot throughout the year 1908-9. in England and Wales, and
(to continue using Mr. Collinge's own words) showing: —

(1) That 67-5 per cent, of the food of the rook consists of

grain ; if to this we add that of roots and fruits, the
percentage is raised to 71 per cent.

(2) The animal food-content was only about 29 per cent., of

which quite one-third must be reckoned against the rook.

June, 1911.

KNOWLEDGE.

237

(3) There is ample evidence to show that, with the present

large nnnibers of rool<s. a grain diet is preferred.

(4) So far as the evidence of this enquiry shows, the rook is

not a particularly beneficial bird to the agricul-
turist, although its usefulness might be consideralily
increased were it fewer in numbers.

This is even more condemnatory of the rook than the figures
which are given in the Transactions of the Highland and
Agricultural Society for 1896, as the result of investigations
made by Sir John Gihnourin Fifeshire. Daring one year, about
thirty rooks were shot and examined each month — three
hundred and fifty-five birds in all — and it was found that
eighty-one per cent, of their food was cereal grain and husk,
with insect and grub : also that grain and husk were at least
as frequently met with as insects and grubs. It is stated that
grain and husk is above everything the food of the rook, and
that a general crusade throughout the countrv should be
waged against rooks and rookeries.

On the other side Mr. Robert Newstead's opinion is that the
rook is, on the whole, decidedly beneficial, though quite
omnivorous and a great destroyer of grain. {The Food of
some British Birds, 1908.)

The rook is scheduled, along with the starling and chaffinch,
as the subject of the first enquiry by the Economic Orni-
thological Committee of the British Association as to the food
of birds, and, from this, further reliable data and facts maybe
e.\pected to be forthcoming ere long.

DECREASE IN THE CORN-CRAKE OR LAND-
RAIL iCREX PRATEXSIS).— In recent numbers of The
Zoologist, correspondents have been giving instances of
changes or fluctuations in the numbers and distribution of
some of our commoner birds. To the present writer the most
interesting case is that of the Corn-crake. Within the last
few years he has had some opportunity of comparing, by field
observations, the bird-life of the Home Counties with that of
the West of Scotland, and. as regards the Corn-crake (a most
familiar species in the last-named district), he has only once
heard it in the course of many outings each season in
Middlese.v, Herts and Bucks. That was on 5th June. 1910,
near Great Missenden. Bucks. This is so greatly at variance
with the statements made in local bird-books, that some
explanation or fresh examination seemed necessary. This has
been forthcoming in some details from the various contributors
to Tlic Zoologist, who unite in agreeing that ihis bird, once
abundant and common, must now be considered scarce over a
wide area including Berks and the Thames Valley, Oxford-
shire, Bedfordshire, Staffordshire, Surrey and Hants. It is, in
one way, consolatory to the present writer to find Mr. O. V.
Aplin, author of "The Birds of Oxfordshire," (18891, saying
that he heard the Corn-crake at Bloxham, in 1910, but had
not done so since 1904.

The scarcity is attributed to destruction of the birds and
their nests by mowing-machines, by birds being killed by flying
into telegraph and telephone wires, by unseason.able summers
and by wetter meadows along the Thames and its tributaries.
But the question may well be asked why the species holds its
own in the West of Scotland, where such conditions are quite
as prevalent as elsewhere in the country.

THE RED GROUSE ON THE CONTINENT.— This
typical British species Lagopus scoticus seems now
to have obtained a secure footing on the Hohe Venn,
an elevated region of moorland situated along the
Germano-Belgian frontier. South of Spa. The first
introductions were made in 1893, but were unsuccessful.
In August, 1894, fifty pairs were imported, and by the
following autumn they had spread all over the locality
named. In 1901, it was estimated that there were one
thousand birds in the two " Kreise " of Malmedy and
Montjoin. Professor W. Somerville, who gives this informa-
tion in Tlie Ihis (April, 1911, page 368), flushed a strong
covey in a short walk over the moor in September last.

A NEW BRITISH BIRD.— Fair Isle has again yielded an
addition to our avi-fauna, Mr. Wm. Eagle Clarke reporting in

the current number of the Annals of Scottish Natural
History (page 70) that an example of Blyth's Reed-Warhler
iAcrocephahis (?;(;);t'Hior!(;») was obtained there in September,
1910. This species resembles the Reed-Warbler, and Marsh-
Warbler closely in colouration, and very careful comparison is
required to distinguish these three forms. It is eastern in
range and is not known to have occurred pr iously west of
St. Petersburg.

WHITE STORK BREEDING IN THE - ZOt),"
LONDON. — A pair of White Storks (Cicouia alba), which
were placed in the sea-gulls' aviary about a year ago, built a
nest there on the ground, laid three eggs, and after twenty-
eight days' incubation, hatched one egg on the 1st May. The
young bird seemed doing well some days thereafter, and it is
hoped may be successfully reared, as this is the first time this
species has bred in the Zoo.

COLLI-CTING AND PROTECTING BIRDS OF
PARADISE. — A great collector describes in the current
number of The Ibis (.April, 1911, pages 350-367) sixteen new
species and sub-species of Birds of Paradise published since
1898. and also gives a complete revised list of all the known
birds of this group. This makes a considerable addition to
our knowledge, the information being given for high scientific
purposes and for the advancement of knowledge. Trinomials
are largely used, and such names occur as Lycocorax
pyrrhopterus pyrrhopterus (Bp.).

.■\ bird "collected," either scientifically or unscientifically, is
accounted for in a final and effective method, although its
remains may be treasured in a museum, and it is something of
a coincidence that the same number of Tlie Ibis (page 403)
contains a plea for preserving Paradise-Birds "from the utter
extinction which will certainly befall them unless some steps
are taken to guard them from destruction." This remark is
made in commending the action of Sir William Ingram, who
has acquired the island of Little Tobago, West Indies, for the
purpose of an experiment in acclimatizing Paradise- Birds.
This is an uninhabited island, except for the keeper who has
been placed upon it to look after the forty-eight living
examples of Paradisea apoda, brought from the Am Islands
and set free on Little Tobago. We trust that the experiment
will command success and shall look forward to hearing of
satisfactory results.

THE BRITISH ORNITHOLOGISTS' UNION
EXPEDITION TO THE SNOW MOUNTAINS OF

NEW GUINEA. — The members of this expedition are now
all returning home, and were to sail from Singapore on 5th
May. Insurmountable difficulties have prevented complete
success attending their efforts, but they attained the top of the
first great mountain-range near the snows ; and considerable
collections of birds, mammals, and other objects, have been
made, which are expected to yield valuable scientific results.
A number of letters from the leader, Capt. Rawling. appear in
Country Life (iOth May, pages 719-23).

PHOTOGRAPHY.

By C. E. Kenneth Mees, D.Sc, F.C.S., F.R.P.S.

THE ROYAL PHOTOGRAPHIC SOCIETY'S
EXHIBITION. — The Fifty-sixth .Annual Exhibition of the
Royal Photographic Society was opened on May 9th, at
Prince's Skating Club. Knightsbridge, W.

The Exhibition of pictures was of considerable interest, the
general collection being augmented by a special loan collection
of photographs of His Majesty, King Edward VII. a number
being lent by Her Majesty Queen Alexandra.

The Pictorial Section was generally considered to be a
satisfactory and representati\e display, and an interesting new
experiment was the Section for General Photography, in which
the pictures were selected for their technical merit.

While some very fine work was shown in this Section,
notably Dr. Thurstan Holland's photograph of the Bernese
Oberland. one cannot help feeling th.at far more first-class

13H

KNOWLEDGE.

June. 1911.

technical work is available than was shown, and that when the
Section has become more familiar to Exhibitors much better
results may be expected.

In Section 3, devoted to Colour- Photography, many
transparencies of scientific interest were shown. Professor
Waymouth Reid showed a splendid collection of Autochromes.
including a very large and fine polarised light figure of the
mineral Barytes.- Other polarisation colour-slides were shown
by Professor Pope. J. G. Bradbury and A. W. Harris.

There is no doubt that for the demonstration of polarised
effects the .Autochrome plate will prove most suitable, and
should in the end win an important place for itself in the class
teaching of Mineralogy.

Of Botanical work also there were many fine examples:
the Alpine flowers of Mr. Somerville Hastings being
conspicuous.

Dr. Drake Brockman showed a number of moths and
butterflies, while Mr. Martin Duncan, Mr. J.I. Pigg and Mr.
P. C. Dalliriger, as well as Prof. Waymouth Reid, showed
photomicrographs in colour.

As a whole the Colour Section must be considered excellent
in quality, and thoroughly representative of the valuable work
that can be done on screenplates.

Of Natural History Photography the present writer is
scarcely competent to speak, but to an outsider the Section
seemed a good one. and many interesting photographs were
shown.

Technicall}', Mr. H. C. Knowles' photograph of the (jreat
American Egret, reproduced in the Exhibition Catalogue, is
excellent work, while the Yawning J.aguar of Mr. H. Irving,
strikes a rather unusual note. Mr. C. J. King contributes a
series of patient studies of Peregrine Falcons, and indeed the
Section is unusually rich in series of photographs illustrating
the life-history of birds and beasts, in which perhaps the chief
scientific value of Natural History photography is to be found-
An excellent example was the series of twelve prints illustra.
ting the life-history of the Nightjar during the nesting period,
by Mr. William Farren. Mr. Pike's photograph of the
Gannet going down wind will appeal to most photographers
and makes one inclined to suggest that it might be an
improvement to this Section, even at the cost of enlarging the
Catalogue, if fuller particulars of the way in which the
photographs were taken were given.

Section 5, which is devoted to Scientific Photography and
Reproduction Processes, was particularly strong this year, both
the Photoniicrographic and X-Ray sections being very represen-
tative. The Astronomical section, containing a large number
of very high-class transparencies, is liable to be somewhat
ignored by the general public. It would perhaps be better if
astronomical workers were to prepare prints from their negatives
for such an Exhibition, even though transparencies show more
detail and better render gradation. Transparencies are very
difficult to hang and light satisfactorily in an Exhibition, and
are therefore liable to be separated from the rest of the
scientific section, and to suffer in consequence.

The first eight frames of the Scientific Section were a collec-
tion of examples of new methods of process reproduction shown
by the London County Council School of Photo-Engraving and
Litho.graphy ; they comprised frames showing the new Rotary
photogravure as applied to newspaper illustration, and also
the improvements in relief methods which the introduction of
intaglio processes has stimulated. There was also an excellent
frame showing Rotary photogravure in colour, and another
showing Photolithograpiiy in colour from half-tone transfers
printed by the oflf-set process.

Immediately after these the photomicrographic section
commenced with a splendid series of high-power photo-
micrographs of diatoms by Dr. T. W. Butcher, which have
received a well-deserved medal. Conspicuous in this section
also were the pathological photomicrographs of Mr. Richard
Mnir. and the bacteria and trypanosomes of Dr. Duncan J.
Reid, an interesting frame. No. 633. by the latter giving full
particulars of the photographic conditions under which a
number of varying objects were taken. A careful studv of

this frame could not f.iil to be of use to any worker in this
subject.

Mr. C. R. Darling showed a series of photographs of drop
formation, the drops consisting of aniline oil suspended in
water.

One of the best photographs, technically, in the whole
Exhibition was Jlr. H. N. Newton's photograph of a dissected
human heart. No. 653, which showed the ventricles and valves
with strengthening cords. .\ large number of photographs of
osmotic growths was shown by Dr. Stephane Leduc. and
others were contributed by Dr. J. Gray Duncanson.

The Radiographic Section vied with that dealing with
Photomicrography in being fully representati\e and of the
highest order. The medal was given to Dr. Thurstan Holland
for his numerous photographs, and was no doubt awarded as
much for the general excellent work which Dr. Holland has done
in perfecting X-Ray technique as for the special photographs
shown at this Exhibition. As Dr. Holland also received a
medal for his photograph in Section 2, he is in the unusual
position of receiving two medals in the same Exhibition.

Other excellent radiographs were shown by Dr. Robert Knox,
whose technical skill closely approaches that of Dr. Holland's,
and by Dr. G. H. Rodman ; while two photographs of the
highest class were sent by Dr. G. T. Haenisch.

The Astronomical Section of the Exhibition was mainly
represented by the many transparencies shown by the Lowell
Obser\atory and b\- Dr. Max \\'olf of Heidelberg. Dr. Wolf
showed a collection of no less than 50 lantern slides, while
Lowell Observatory sent a series of photographs of Saturn
and Jupiter, and of Comet a 1910 and of Halley's Comet, the
spectrum of Halley's Comet being also shown.

In Spectroscopy, Professor 2eeman received a medal for his
absorption lines of Sodium in a magnetic field, the resolution
being very clearly shown. The definition which can be
obtained in Spectroscopy under the best conditions was well
shown by Mr. Stanley in his enlarged photographs of the iron
and aluminium arc spectra.

Many other interesting photographs were shown, but one
cannot help feeling that an Exhibition such as this might be
made much more fully representatix'e of the application of
photography to science, if scientific workers generally would
take more interest in it and endeavour to make use of the
opportunity of la\-ing their results before the general public.

PHYSICS.

By A. C. G. Egerton, B.Sc.

OPTICAL PROPERTIES OF VAPOURS.— Professor
R. W. Wood has recently delivered three lectures at the
Royal Institution, on the optical properties of vapours. These
lectures were illustrated by experiments, illustrating most
beautifully the various phenomena referred to by the lecturer,
who is a master of the art of designing experiments and whose
ingenuity is unbounded.

His first lecture dealt with the absorption of light by
vapours. Many substances have a definite colour in the
gaseous state ; nitrogen peroxide is brown, iodine vapour
violet, chlorine green, nitrosodimethylaniline green — a few of
many examples. If light, after passing through such gases, is
analysed bj- a spectroscope, the spectrum will be crossed by
dark lines and in some cases by dark bands. The light of
these wave-lengths corresponding to the dark lines and bands
has been absorbed by the vapour. In the same way the light
from the photosphere of the sun is absorbed by the layers of
vapour round the sun constituting its atmosphere : dark lines
then make their appearance in the sun's spectrum correspond-
ing to the elements in the state of vapour in the sun. At the
time of an eclipse, when the moon hides the sun's disc-like
form, the spectrum of the corona is often found to contain
bright lines in the neighbourhood of prominent absorption
bands in the solar spectrum, those about the yellow sodium
lines being peculiarly prominent. It was not easy to explain
how the " reversing " layer, or the layer of gas responsible for
the absorption of the light from the photosphere should be
hot enough to emit light of its own. This particular bright

Junk. 1911.

KNOWLEDGE.

239

line spectrum has been termed the '" flash " spectrum.
Before bein? able to give the true explanation of the flash
spectrum, it is necessary to explain what is meant by
dispersion.

If white light be passed through a glass prism, it is not only
bent and deviated by an amount proportional to the
"refractive index" of the glass, but it is also split up into a
spectrum, the red light being less deviated than the violet;
this is termed the "dispersion" of the light. Now light is
refracted more by a dense glass prism than by a light crown
glass prism of the same angle, but it does not necessarily
follow that the dispersion is proportional to the " refractive "
power {i.e., to the refractive index! of the glass. It is this
that makes it possible to construct achromatic prisms and
lenses : the dispersion of one prism can be counteracted by
that of a dense flint glass prism though the deviation or
refraction of the beam of light is still obtained. Newton
arrived at the conclusion that dispersion was proportional to
refraction; this was erroneous. If the refractive indices be
plotted against the wave-lengths of the light passed through
various substances, it is not always found that the substances
of high mean refractive index give great dispersive powers, or
steep curves, when plotted as mentioned.

Kundt found in examining the absorption spectra and
dispersion curves of many dyes, that such highly coloured
substances which show strong absorption bands, give what
has been termed " anomalous dispersion " in the neighbour-
hood of these bands. Instead of increasing as the wave-length
decreases, the refractive index increases very rapidly on the
red side of the absorption band and decreases towards the
blue side of the band. " Normal " dispersion is merely a
p.irticular case of the general phenomena of dispersion ; the
band near which the dispersion is " anomalous " lying, for
transparent colourless substances, in the ultra violet invisible
region of the spectrum.

Returning now to the sun and considering its " flash "
spectrum, it follows that the refractive index in the neighbour-
hood of an absorption band, due to some vapour or other, will
increase very rapidly : it will be very small except close to the
absorption band, hence light nearly corresponding in wave-
length to the absorption band will alone be sorted out and
bent sufficiently for it to reach the earth, when the moon has
blocked out all direct light from the photosphere. This
beautiful explanation is due to W. H. Juhus, but Professor
Wood has been able to reproduce the phenomenon experi-
mentally, thus confirming the correctness of the theory.

It will be well first to describe Professor Wood's method of
illustrating the anomalous dispersion of sodium vapour. A
long glass tube with pieces of sodium strewn on the bottom is
fitted w'ith plate glass ends and exhausted. It is then heated
by carefully adjusted Bunsen burners. The upper surface of
the tube being cool, the density of the vapour decreases as its
distance from the heated sodium. It then forms what is
equivalent to a prism of sodium vapour. Light from an arc
lamp passed through a slit and then through the sodium prism
is absorbed by the vapour which, by the way, when dense, has
a blue violet colour ; particularly absorbed are those wave-
lengths corresponding to the yellow " D " lines. There are
also absorption bands in the green and red. Now, in the
neighbourhood of the " D " absorption bands, the vapour will
have an abnormally high refractive index for w-a\'es slightly
longer than those which it absorbs and an abnormally low
refractive index for waves slightly shorter than those which it
absorbs. Thus yellow light passing through the sodium
vapour prism will be very highly dispersed, the wave-lengths
on either side of the absorption bands being most widely
separated. If the light be now observed in a spectroscope with
the refracting edges of the prisms at right angles to the
edge of the sodium prism, the light in the neighbourhood of
the " D " absorption lines will curve up on the one side of the
band and down on the other side owing to the great dispersion
of the sodium vapour for light of wave-lengths in this
neighbourhood. Professor W'ood was able to project the
artificial " flash " spectrum of sodium on the screen. Light
from an arc is projected through a narrow horizontal slit
along the lower edge of a metal plate heated by a Bunsen fed

with sodium which colours the flame \-ellow. The light on
lea\ing the plate is almost completely screened off, passed
through a prism and projected on the screen. The metal
plate lowers the temperature of the flame and the sodium
vapour no longer emits light in its neighbourhood. The light
passing through this layer of sodium vapour is anomalously
dispersed in the yellow region. The rays on eii'.ier side of the
absorption bands are refracted differently, the vine ray being
bent upw-ards and the other down. The screen being adjusted
to cut oft' the direct light from the arc, the yellow light bent
upwards suddenly "flashes" out on the screen. This then
illustrates what is occurring in the sun's atmosphere.

The second lecture dealt with the emission of light by vapours.
X'apours can be made to emit light by the passage of electricity
through them when the electrons in the ions are greatly
disturbed and set in vibration. The disturbance in this case
is eftected by many causes ; it is better then to look for a less
complicated method of setting the electrons in vibration in
order to discover something about the structure of the atom.
Those vapours which absorb light and hence have a definite
colour can be made to emit light by heating them. Professor
Wood showed how- iodine dropped into a quartz bulb heated
to a high temperature, is \aporised and glows^the vapour
appearing " red-hot." White light passed obliquely
through a steel tube in which sodium is vaporised
causes the sodium to fluoresce or emit light of
a green colour by stimulation. In the same way light
passed through a bulb containing iodine vapour at a very
low pressure causes the vapour to fluoresce with an olive green
hue. The presence of a small quantity of helium changes
this hue to a reddish tint, while other gases destroy the
fluorescence in proportion partly to their molecular weight
and partly to their electro-negative character ; a very
small quantity of chlorine destroys the fluorescence altogether.
Mercury vapour will fluoresce at much higher pressure ;
Professor Wood illustr.ated this point by projecting light from
a magnesium spark on a quartz bulb in which mercurv was
boiled : the mercury vapour, when all the air had been expelled
from the flask, lit up with a blue colour. Iodine when heated
emits light of the same wave-length as it absorbs : the electrons
in the molecule are set in vibration by the process of heating
the vapour and give out particular wave lengths of light, just
in the same way as these waves are absorbed on passing
through the vapour, their energy being absorbed by setting in
motion those electrons which vibrate with the same period of
vibration. White light passed through such a vapour,
provided the pressure is not great enough to prevent the
free vibration of the electrons by the collision of the mole-
cules, will give rise to fluorescence. If instead of employing
white light, light of a particular wave-length be employed, then
this light will aft'ect only certain electrons which vibrate with
the same period, and these in turn being grouped with only a
few other electrons in the molecule will set in vibration only
a few other electrons possessing different periods of vibration ;
only a few lines then appear in the spectrum of the light from
iodine vapour set resonating by the light from the mercury
arc. Professor Wood has studied these resonance spectra
most elaborately and amassed much interesting material from
which to obtain a glinipse of the atomic structure.

The third lecture dealt with the eft'ect of magnetism on the
optical properties of vapour. Light from an arc lamp was
passed through a well-evacuated tube containing sodium
vapour placed across the poles of an electromagnet; the light
before it entered the tube was polarised by a Nicol prism and
only permitted to vibrate in one plane. On emerging from
the tube, the light was passed through a second Nicol prism,
so that the prism either permitted the polarized light to pass
or, by setting it at right angles to the plane of vibration of the
waves, it could prevent the light from reaching the screen. An
ordinary glass prism refracted the emerging light on to a
screen and formed a spectrum on the screen. The second
Nicol was so arranged that it almost extinguished the spectrum.
The magnetic field was switched on and immediately the sodium
yellow lines could be easily seen on the screen. In this experi-
ment the magnetic field rotates the plane of polarization
round through a right angle or some multiple thereof, thus

240

KNOWLEDGE.

June. 1911.

permitting the light to get through the second prism. The
rotation is only produced where the refractive index of the
vapour is very high, namely in the neighbourhood of the
sodium flames. If the sodium vapour be very dense, the
beam of yellow light will be twisted round and round many
times. The light examined in the spectroscope is shown to
consist of a number of light and dark spaces on each side of
the " D " lines. 'each line representing a rotation of the beam
through 180'. In some cases the direction of the rotation of
the plane of polarization is opposite to that of other wave-
lengths, which Professor Wood has shown by means of a most
ingenious double quarts prism of right and left handed
rotation. The rotation of the plane of polarization of the light
in the neighbourhood of the absorption bands of iodine was
shown : the little monochromatic elements in the spectrum are
selected out and give a line spectrum. Professor Wood
referred finally to the reflecting power of vapours which if the
absorbing power is great sho\ild also be. great. He has been
successful in obtaining reflection from mercury vapour under
high pressure in quartz vessels when illuminated by ultra-
violet light.

ZOOLOGY.

Hv Professor J. .Xrthur Thomson. M.A.

ARTIFICIAL PAKTHKNOGKNESIS.— It is now reported
that the eggs of frogs and toads may be got to develop wdthout
fertilisation. Bataillou takes a piece of a string ot toad's
spawn with as little jelly as possible, puts it in a dry dish,
bathes it with a little blood, and makes minute punctures in
the eggs. They segment " magnificently," and the frog's blood
works as well as the toad's, and better than the spermatozoa
of the frog I Dehorne has made a careful study of a frog
larva parthenogenetically produced which lived for eight days.
The cells of its body had. as theory would lead one to expect,
only six chromosomes in their nuclei. — half the normal number.

.\ CL'KIOL'S HABIT. — Erik Rergstrom calls attention to
a puzzling piece of behaviour which he has noticed in
reindeers at the time of antler-growth. With some difliculty
they frequently bring the tip of the antler into contact with
the hoof-gland, and the result is that the tip is smeared with
the viscid secretion. Hut why ?

KINGS ON FRESHWATER MUSSELS.— There is some
peculiar satisfaction in observing the organic registration of
growth-periods, — so familiar in the rings of wood on the sawn
tree-stem. It is strikiiig. too, to read back to a peculiar line
where there seems to have been no summer wood formed, and
to find, on consulting the meteorological calendar, that this
corresponds to what was called '' the black year," when there
was no summer. So from the scales of a fish, or from its
otoliths, or even from some of its bones, one may read its age
with security, corroborating one index by another. According
to Malloch one can tell from the salmon's scales whether it has
spawned or not. and more besides. A case that has always
interested us. becau,se of the great variety in the succession,
is that of the rings on freshwater mussels, but we are not
aware of precise observations on the subject. In a recent
paper Israel points out that two rings are sometimes laid down
in one year.

FLIES .AND ERGOT. — We have heard much in recent
years of the part that flies play in disseminating disease-germs
— typhus-bacilli, sleeping sickness Trypanosomes, and many
others. It is interesting to notice that L. Mercier has found
that a common summer fly. Sciara tkomac, carries about the
spores of Claviccps which causes ergot on rye-grass. The
conidia of the Claviccps were abundant in the food-canal of
the flv and did not seem to be affected. There were also
others on the setae of the body. The flies frequent rve-grass,
but experimental proof that they infect healthy plants with
Claviccps has not yet been furnished.

SPIDERS AND MOSOUITOES. — N. Leon gives an
accoimt of the formidable numbers of Mostjuitoes in Roumania
along the shores of the Danube. E%ery here and there, in
some tracts, one sees the canopied al fresco beds where the
fishermen sleep, or try to sleep. Equally characteristic is the
astonishing abundance of spiders' webs which sometimes
cover the trees with a thick veil. These are of no slight
importance in imposing some check on the multiplication of
the mosquitoes. As things are, the plague is sometimes
terrif\ing. but it would be much worse without the spiders.

HVDRACTINIA AND HllKMlT CKAH.— Prof. Seitaro
Goto, of Tokyo, describes two species of Hydractiiiia which
occur in Japanese waters in association with a hermit crab
(Etipagunis coiistaiisK and form shells of their own entirely
composed of a chitinous framework. In most specimens there
is apparently no basis of gastropod shell, as is the casein most
other known species of Hydractiiiia. The skeleton of one of
the species (//. spiralis sp. n.) is totally devoid of spines, and
its substance is very thin and papery, while that of the other
IH. soilalis Stimpson) is richly armed with large spines, which
arc conical when small, but irregular in shape and branching
when large. The skeletons of this species are rather common
and are sold in a dry state under the name " Igaguri-gai," or
" Chestnut-burr shell."

SPECIFICITY.— The late Mr. George Sim. of Aberdeen,
author of " The Vertebrate F~auna of Dee," was wont to say
that he could identify any British fish from a square inch of
its skin. In other words, the scales of each species have
distinctive peculiarities. They show specificity. And the
more we know of the members of well-defined species the
more we become convinced of the unity of the organism.
Distinctiveness penetrates into every hole and corner. A
striking illustration has recently been given by W. J. Loginoff,
who shows that the ciliated cells hning the windpipe of horse,
ox, sheep, and so on, are so distinctive in each case that it is
not very difficult to tell from a preparation what animal it
came from.

By Wii.i'RED Mark Wehh. F.L.S.

THE FAIRY SHRIMP.— It is interesting to record that
Mr. B. J. Hunter has recently found examples of the F'airy
Shrimp in ponds near Pewsey in Wiltshire. Commenting on
the fact mentioned by Mr. Pyman (" Knowledge," Volume

XXXIII, page 251) that the styles projecting from the telson of
the female were usually broken, Mr. Hunter says that he
noticed "a small animal that seemed to have a bivalve shell,
which propelled itself rapidly through the water by means of
its feet, attached itself to these styles and ate them, the
shrimp appearing not to notice it until it had reached quite a
distance when, by means of a powerful jerk, it was thrown off."

FLEAS AND PLAGUE.— In " Knowledge," Volume

XXXIV, page 12, Mr. Grew, in deahng with the question as
to whether there was much likelihood of fleas carrying plague
in Europe, gave the generally accepted opinion that the
luiropean rat flea. Ccratophyllus fasciatiis, will not feed
on man except when starving. Quite recently a number of
experiments have been made at the Lister Institute of
Preventive Medicine by L")r. Harriette Chick and Dr. C. J.
Martin, which have been published in The Journal of Hygiene
for .^pril Sth, and Dr. Chick has kindly sent us a reprint
from which we learn that Ccratophyllus fasciatus, when
hungry, will attach itself to man with great readiness. A
hundred and sixty-one experiments were made, of which we
describe one. A rat was removed from a flea-breeding cage,
and four days later the hand and arm of a number of persons
were placed in the cage at difl'erent times during the day for
two minutes. In one instance as man\- as eighteen fleas
jumped upon the arm, many of which could be felt at once to
bite vigorously.

REVIEWS.

ASTRONOMY.

The XigJif-SL-ics of a Year.Sy J. H. Elgie. 260 pages.
113 illustrations. Sj-in. X 5i-in.

(Leeds; Chorley & Pickersgill. Price 6 • net.)

The author adopts the course of noting down in a simple
manner what he saw when viewing the sUy at night, free from
clouds, several times each month : it thus assumes the nature
of a diary or journal, and is divided into the twelve months.

It is solely intended for those who are content to learn the
positions and something of the stars in their courses ; there-
fore, for a non-telescopic observer. The author adopts this
journal form as the best way to meet the requirements of that
large class of intending observers who are said to find the
usual star-maps and books too full and bewildering in the
number of stars dealt with. He prefers to give in the text
diagrams of portions of the constellations and usually limits
himself to the first, second, and third magnitude stars : in this
way the most prominent and well-known configurations are
represented.

Throughout the book the author, who has evidently a poetic
fancy, has enlivened his bare bones of astronomical observa-
tions with historical facts, with opinions of various writers,
and with frequent dives among the poets, from Chaucer's
time. Though we are not enamoured with poetic effusions,
being accustomed to the more solid branch of astronomy
dealing with observations of facts and with figures, to those
who like poetry and poetic imagination the book should
at once appeal ; they should not fail to obtain a copy and
verify for themselves all that is stated therein, and, in learning
the stars, they may contemplate upon them as suits the human
mind.

The table of contents gives in detail the subjects referred to
each month and a list of diagrams is similarly given. .A full
index of eighteen pages is at the end of the book, which is well
printed in type of good size. ., , „

Rciiiarkahlc Eclipacs. — By W. T. Lynn. (Eleventh edition).

3.S pages. 1 plate. 6T-in. X 4T-in,

Rcnutrl^dhlc Comets. — By W. T. Lynn, (h'ifteenth edition).

4,S pages. 2 plates.

(S. Bagster & Sons. Price 6d. each, limp cloth.)

There is always a freshness in the successive editions of

these valuable, useful, and popular little books : not mere

reprints of former editions. For beginners in Astronomy they

serve both as introductions to the subject and as historical

accounts. The one referring to the eclipses is quite a marvel

of compact'.'iess, embracing a period of eclipses for three

thousand years (B.C. 1063 to .\.D. 1999), and every page is

crammed with interesting scientific and historical facts. The

first two pages, explaining the nature of an eclipse, might, with

advantage, be extended to three or even four, and a diagram

inserted. Tables of contents are given at the end. The little

book relating to comets meets with our approval in a similar

manner. It, however, mainly deals with the more prominent

comets of the past three hundred years; the ancient records

are less precise and cannot be verified so well as eclipses by

ante-dated calculations. Two useful books by a trusted

author. The title of these little books might be. with

advantage, printed on the back: an unlabelled book on a

bookshelf is a nuisance. ,, , ,,

r. A. b.

The Stars from "S'ear to War. — Edited by Mrs. H. P.

Hawkins. Fourth edition. 1 1 pages. 13 maps. (Price 1 •).
Tlie Star .Almanac for 1911. — Same editor. Second edition.

Large illustrated sheet. (Price fid.)
The Star Caleiular for 191 1 . — Same editor. Card planisphere.
(Price 1/-.)
(Simpkin. Marshall. Hamilton, Kent & Co., and others.)
These three publications are of considerable utility to all sky-
watchers at night. There is an abu;idance of information for

all enthusiastic beginners in Astronomy, and the star-maps
will certainly serve them when their knowledge has emerged
beyond that of a no\ice. These books might well be within
most country households — and the stars are observed far too
little by those living away from towns, with brightly lit and
dusty atmosphere — whether the squire's, the parson's, the
schoolmaster's, or governess's. If they were in the hands of
school-teachers and those with the educational care of children,
much simple astronomy might be imparted to those entrusted
to them.

The prices at which these publications are offered, bring
them within the reach of all : the typographical reproduction
is excellent.

F, A. B.

CHEMISTRY.

The Sniil^lc Carhnhydrates ami Gl iicosules. — liy E.
Fkaxki.anu Armsirong, D.Sc, Ph. P. 112 pages.
10}-in.X6-in.

(Longmans. Green & Co. Price 3 6 net.)

Even in physiological chemistry the process of specialisation
has proceeded so far that no worker may hope to keep fully in
touch with more than one or two branches of his subject. It
was, therefore, a happy idea of the editors of this series of
small handbooks upon biochemistry to issue concise mono-
graphs dealing with separate classes of physiological compounds,
so arranged that they would be useful for purposes of
reference, and capable of being brought up-to-date from time
to time, without the necessity of issuing a new edition of the
whole series. Various companions of this book, dealing wrth
proteins, fats, enzymes and so on. have already been noticed
in these columns, and the present monograph, which is
devoted to the simple sugars and glucosides, follows the same
general plan. Dextrose (glucose) is taken as the type of these
sugars, since, as the author points out. it is probably the first
sugar formed synthetically by the plant by way of formal-
dehyde from the carbon dioxide in the air, and is also the
form in which a large proportion of the carbohydrates in the
food of animals is absorbed into the system. The chapter
discussing the relationship between the chemical configuration
of the sugar molecule and its biochemical properties is
particularly interesting. -As in the case of the other mono-
graphs of the series there is an excellent bibliography and a
good index, and every chemist who is interested directly or
indirectly in the subject of the sugars will find this book of the
greatest use. .- , , ,

Elementary Chemical Theory. — By J. M. Waii>[0K1,. M..\.
(Oxon). 275 pages. 16 illustrations, "-l-in. x 5-in.

(Methuen & Co. Price 3 6.)

If we were asked to recommend a guide to the elements of
chemical theory suitable for students at an early period of
their work, we could suggest nothing better than this book.
It is clearly and simply written, and the author's experience as
a teacher of beginners has enabled him to anticipate and
answer the chief difficulties that will arise. It deals at
sufficient length \\ ith most of the subjects usually found in the
larger works upon the theory of Chemistry, and has an
excellent chapter upon radio-activity and its bearing upon the
possible constitution of the elements. Perhaps, in a future
edition, it may be found possible to devote more attention to
the " phase rule," and the principles of thermo-chemistry.

.although the author anticipates ine\ itable criticism upon
his use of the hydrogen standard for the atomic weights, and
gives good reasons for its retention, we still think that an early
adoption of the oxygen standard would be the better course.
For since the use of H = 1 has been discarded in the annual
tables of International Atomic Weights, all scientific work is
now based upon the standard of 0 = 16. Hence to accustom
students to the use of values which in practice they « ill ha\e

241

242

KNOWLEDGE.

June, 1911.

to unlearn, seems a greater evil than the difficulty of making
the fact clear that the value 16 is only an arbitrary standard,
and the possibility that some students may acquire for a time
the notion that atomic weights are necessarily whole numbers.
By the way. why was a table of atomic weights of 1905 chosen
for the appendi.x ? The current table contains several more
elements and gives \alues differing in many respects from those
in a table that h&s been out of date for five vears.

C. A. M.

A Concise History of Chemistry. By T. P. Hiluitch.

B.Sc. A.I.C. 263 pages. 16 illustrations. 75-in.X5-in.

(Methuen & Co. Price 2 6.1

It is no easy task to survey, within the limits of one small
volume, the entire history of chemistry, from the days of
alchemy to the present time, and in this case the difficulty was
increased by the fact that the book was also designed to meet
the requirements of certain examinations in the subject of
historical chemistry. A book upon these lines runs the risk
of being little more than a skeleton of facts, names and dates.
The author, however, has escaped this pitfall, and has given
us a most readable outline without sacrificing the necessary
compression, and has enabled ns to follow easily the
development of the main theories of modern chemistry.
There is also an e.xcellent account of the history of the different
elements and their chief compounds, and the book concludes
with biographical notes of many of the great chemists, tables
summarising the sequence of discoveries and theories, and a
good name and subject index.

The chief fault in the book is the complete omission of anv
reference to many important branches of the science, such as
biological chemistry, and the scanty treatment of other
subjects. For instance, in the section dealing with technical
chemistry the subject of oils and fats is mentioned, but there
is no reference to any worker of later date than Chevreul ;
while in the account of the progress of experimental methods
there is no mention of the now classical iodine absorption
method of von Hiibl.

The selection of the names included in the biographical
notes appears somewhat capricious. Thus the names of
Odling and of Newlands are omitted, while the names of many
whose contributions to chemistry have been of much less
weight are included. Doubtless these omissions will be
remedied in the next edition.

C.A. M.

All liifnuliictioii to Cliciiiiciil Theory. — Second edition.
By .\, Scott, D,Sc., F,K.S. 272 pages, iS|-in, x Dj-in,

(Adam and Charles Black. Price 5 - net.)

Slowly, out of a confused mass of p.iintully accuumlated
detail, there has been evolved a philosophy of chemistry which
has shown that there was a certain law and order connecting
the apparently isolated facts. Several large works upon the
subject have appeared from the pens of such masters as
Mendeleef and Ostwald. and the present handbook,
which has deservedly reached its second edition, forms an
excellent introduction to these. It takes a brief survey over
the whole ground upon which the theory of chemistry has
been raised, and is so fully and clearly written as to be easily
followed by any student who has acquired some knowledge of
the facts of the science. Among the subjects treated .at
considerable length in the difierent chapters are the determina-
tion of atomic weights, classification of the elements, carbon
compounds, the principles of thermal chemistry, and solution
and electrolysis, and these are illustrated by numerical
examples wherever necessary.

The author's aim has been to deal only with points concern-
ing which there is little or no dispute, and as far as possible to
exclude speculative matter; but we venture to think that
there has been a somewhat too rigid .adherence to this rule in
a book, one of the objects of which should be to stimulate the
imagination of the reader. Thus the subject of radio-activity
is practically ignored, although it is in this direction that most
progress in the immediate future may be expected. In the

few remarks upon radium (page 70) some doubt is implied as
to whether that substance is really an element ; but since this
view is opposed to the now generally accepted opinion — an
opinion based upon the properties of radium and its salts, its
position in the periodic system, and its characteristic spectrum
— it would have been of interest to have learned the reasons
for this doubt.

The book is clearl>- printed in large type, and has a good
index, but its use as a handbook would ha\e been enormously
increased by references to the original papers and by the

addition of a classified bibliograpliy.

M.VTHKMATICS.

C. A. M.

.4 First liooh of Geometry. — By J. \'. H. Coat);s, B.Sc.
142 pages. 1 27 illustrations. 7-in. X 4vin.

(Macniillan & Co. Price 1,6.)

This book seems to have been compiled in compliance with
the recommendations recently issued by the Board of Educa-
tion, on the teaching of Elementary Geometry. Naturally
there is nothing new except in the arrangement of the subject
matter, and in some pleasing pictures of a small boy in

knickerbockers engaged in " field work." ,,, ,^ ,,

W , IJ, r..

Elements of .\na\ytieal Geometry. — By G. A. (ilHbON,

M.A., LL.n!, and P. Pixkerton, M.A., D.Sc. 475 pages.

149 illustrations. 7i-in. x5-in.

(Macniillan lS: Co. Price 7 6.1
This biiok contains a great deal of matter not usually
included in elementary treatises on Cartesian Geometry.
Much space is allotted to the plotting of curves, and not only
curves of the second degree, but some of what are usually
classed as Higher Plane Curves are discussed as fully as
elementary methods permit. Geometrical treatment after the
manner of Euclid is freely adopted, so that the chapters on
Conic Sections are a combination of analytical and geometri-
cal methods. There was no real justification for the separation
of the two in older books, and this one seems to include all the
essential parts of what we used to learn as Geometrical
Conies, We hoped to have found the notation of the Calculus
introduced somewhere in the book. Surely it must be
possible to combine the elements of Differential Calculus with
the elements of .Analytical Geometry in a way that is less
tedious and yet not unsound. Here the authors, instead of
making the beginner's yoke lighter, have added to it, and the
bei^inuings of the Calculus seem further off than ever. But a
student who has worked through this book will be thoroughly
prep.ared for it when at length it does come.

\V. D. E.

IIX'HNCJLOGV.

Journal of the Mnnieipal Sehool of Teelinology, Man-

chester.—Xo]. III. 1910. Edited by J. Baknes, M.A., B.Sc.

392 pages. 130 illustrations. 9T-in. X 7i-in.

(The Education Committee.)

This journal forms a record of original investigations under-
taken by members of the Teaching Staff and Students of the
School in the Session 1909. In most cases the papers have
been reprinted from the journals and publications of learned
societies.

Although the application of science to industry is the object
of the instruction given in the school, the researches contri-
buted by the %arious dcpartu\ents are not entirely techno-
logical ; theoretical investigations have not been shirked, but
indeed form quite a large part of some of the papers.

Mechanical Engineering is represented by three important
investigations : — Professor J, T. Nicholson's masterly research
of " Heat Transmission in Steam Boilers," .i further
paper on the same lines by Mr, H. P, Jordan, and an
exhaustive account of some experimental work on "Twist
Drills." Well-illustrated dissertations on " Single-Phase
Traction." " \'ai^aboud Currents," " Elash-Over Voltages,"

243

KNOWLEDGE.

June. 1911.

and some notes on the " Elimination of Sparking " are con-
tributed by the staff and students of the Electrical Engineering
Department.

.•\n important contribution to the subject of \'entilation is
made by Professor J. Radcliffe.

A number of new methods in Volumetric Analysis are
described, also a modification of the Beclcmann apparatus by
Dr. Knecht. The dyeing industry receives a large share of
attention, especially in its application to cotton fabrics,
while even the colouring matter in niunnny cloths has been
investigated I

Weaving, of which we should have expected to hear much,
has only one short paper devoted to it. This, a twelve page
monograph on " The Effect of Twist upon Yarns," consists
mainly of a detailed description of three plates depicting
" single " and " double '" yarns in various stages of twist.

The report to the Government on the Hand Loom Industry
in Bombay is also included in the \olume.

The journal is printed in the Printing Crafts Department of
the School, on which it reflects some credit.

P. K.

CORRESPONDENCE.

H.ALLEY'S COMET.
To flic Editors of " Knowledge."' '

Sirs, — I shall be glad if any one of your readers or
contributors of astronomical articles will please explain to
me, through " Knowledge." why the tail of Halley's Comet
was shown divided into one on the east before dawn, another
on the west after dusk, instead of one on the north and
another on the south, when our globe entered into the tail
of the comet in the morning of the 19th May, 1910. Is the
cau.se of the division of the tail the magnetic repulsion of
the earth ?

I should also like to know whether the tail of Halley's
Comet actually touched the atmosphere of the earth or not?

K. G. CHANDR.^.

THE ETERNAL RETURN.
To flic Editors of " Knowledge."

Sirs, — I should like to say a few words on the above
subject. I have dealt with the matter from the theological
point of view in two letters which have recently appeared in
the \c'iC Age criticising some articles on " Theology " by
" M.B. Oxon."

First, it is necessary to realise that one's know-ledge of the
■' external w-orld " and the phenomena which occur there is
primarily obtained by sensations, these sensations necessarily
depending upon the nature of the corresponding sense organs.
Most of us think principally in visual impressions Iretinal
images) ; and since the shape of these images depends upon
the structure of the eye, it is open to question to what extent
the relation of the images in the mind is a true representation
of the '■ external " phenomena.

Space, time, force, motion are so intimately associated with
" consciousness " that there is a good deal of reason for
asking whether they really exist apart from consciousness. I
often wish scientific people felt more than they appear to
do, that whatever line of investigation into the underlying
processes of nature is taken, the rock-bottom arrived at is
the consciousness of the investigator. One may reduce the
whole cosmos, including humanity, to motion and force — but
these are effects in consciousness.

It is very gratifying to see the notion of space of more than
three dimensions entertained by Professor Pickering, If only
the conception were more readily entertained by astronomers,
physicists and biologists, many astounding results might follow.

The possibility that the bodies of the solar system are
something more than spheres, as a sphere or cylinder is
something more than a circle — the possibility that organisms
(including man) are something more than three-dimensional
entities — opens up a province of speculation which might not
be devoid of practical results. However, since dimension
depends upon consciousness, one has to be careful in talking
of dimensions of which the human mind is not " consciously "

^°""'='°""- J. JOHN ELLIOTT,

COSMIC CHANGES.
To file Editors of " Knowledge."

Sirs, — In the recent work of Dr. .Alfred Russel Wallace,
" The World of Life," the following statement occurs
" , . . . there have been cosmic changes due to the varying
eccentricity of the earth's orbit and the precession of the
equinoxes, leading to alternations of hot. short summers with
long, cold winters, and the reverse ; culminating at very
distant intervals in warm and equable climates over the
whole land surface of the globe ; at other shorter and rarer
periods in more or less severe " ice ages," like that in which
the whole north temperate zone was plunged during the
Pleistocene period, , , ,"

Can any of your readers give a proof of the cosmic changes
due to varying eccentricity and precession of the equinoxes ?

•AN.XIOIS."

IS SPACE INFINITE?

To the Editors of " Knowledge,"

Sirs, — Surely it is easier to conceive of infinity than of
finity ? In considering this ijuestion one must assmiie that one
has the power of illimitable flight ; one must deal with the
question on a practical basis. Your correspondent talks about
curved space. Now, however slight is the curve, some sort of
limit is suggested of which we are on one side. What is on
the other ? Either absolutely nothing, i.e.. infinity or something,
in which case we should have to start afresh. To my mind
the very fact of talking of finity, tacitly admits infinity. Directly
one talks about a boundary, the "other side" must always be
considered.

It is also interesting to speculate about time, such as we
know it. Suppose that all our systems by which we measure
time were taken away, and that man lived on the surface of a
dark earth, let us suppose, absolutely the only sphere in
existence, — would time still be considered to exist ? It would
exist, and yet it is strange to think upon. CHER

SCIENTIFIC NOTES.
To the Editors of " Knowledge."

Sirs, — In reading a paper by William R. Kenwick on
" Insects Destructive to Books" reprinted from The American
Journal of Pharmacy, I came across the following which is
well worth attention : — " Too little attention has been given to
the manuscript notes of scientific workers, often only a line or
two of their observations upon the small forms of life. The
average scientific man, thinking it too trivial to notice, often
passes over the very observation which is the key to the puzzle
that he has been spending years in trying to sol\e."

It cannot be emphasized too strongly that real advance in
knowledge, in any branch of science, is only to be made by
the worker who pays attention to the minute details, and who
regards nothing as too trifling to be worthy of record.

FRANK C. DENNETT.

WILLIAM HERSCHEL : HIS TELESCOPES

AND WORK.

Bv \V. F. DENNING. F.K..\.S.

William Herschel completed his first telescope in March.
1774, and made his last observation in June, 1S21. What a
period of activity those forty-seven years included! His
sister Carolina assisted him in his observations, while his
brother Alexander helped hiui in constructing telescopes.

When Herschel came upon the scene and recognised the
requirements of practical astronomy the heavens had not been
explored — Nebulae and double stars existed in myriads but
only in a few special instances had they been suitably
recorded. He resolved to search the firmament, to reap the
harvest of wonders it presented, and to properly arrange and
classify them for the advantage of ages to come. So he
swept the sky year after year with a skill unmatched, an
energy indomitable, and a success beyond anticipation. He
was a star indeed risen amid the dawn of a new astronomy.
He sounded the depths of space and brought to light great
numbers of interesting objects never previously discerned by
human eyes. When his work was done the hea\ens had
given up many of its secrets.

He had advanced our knowledge, in a marvellously com-
prehensive manner, of the great expanse around ns, and
posterity w'ill honour his name as that of a great pioneer in
the field of methodical ob.servation.

Yet he was not backed up by any national institution,
endowment, or observatory. He was a comparatively poor
man, but with a genius within him which conceived a noble
work, and mechanical abilities which enabled him to fashion
with his own hands the telescopes he required. True his
Sovereign encouraged and pecuniarily assisted him after he had
gained renown. But without any help from George III. his
great career was assured — Herscliel would have been Herschel
still I

The quality of Herschel's telescopes has been sometimes
discussed, and the subject is interesting, though differences of
opinion must necessarily exist. We can hardly think that
telescopes made more than a century ago could equal the best
appliances of our own day. We must have learnt something,
and approached a little nearer perfection during the last
hundred years. Old mirrors carefully tested alongside
Calver's and ^^"ith's best work might be expected to suffer in
the comparison : at any rate that seems to be the reasonable
inference.

But we may depend upon it that Herschel's mirrors were
as good as they could be made in his day. and that they
were very excellent in certain cases is sufficiently evident
from his own allusions, and from the high powers he
occasionally utilized so successfully.

It may in some degree elucidate the question if a few
quotations are made from Herschel's writings. .And in gi\ing
this evidence relatively to his telescopes I should like to
mention that my intention is merely to mention facts on both
sides of the case, and give no expression of opinion. .'Xt this
distance of time it would be in bad taste, and certainly unjust,
to disparage the instruments with which such splendid results
were achieved. No doubt Herschel's powers were such that
he could have made discoveries with relatively inferior
instruments, but we have his word for it tliat liis telescopes
were of far different character from that.

On April 12th, 1805, he speaks of viewing "Saturn with
a power of five hundred and seventy on a seven-feet mirror

of six and three-tenths inches aperture and extraordinary
distinctness."

Referring to the seventh satellite of Saturn, he says he
" saw it very well in the twenty-feet reflector, to which the
extjuisite figure of the speculum not a little contributes." —
.•\ugust 2Sth, 1789.

On October 24th, 17Q1. with a " seven-feet reflector, having
a new machine-polished, most excellent speculum, I see that
the division in the ring of Saturn and the open space between
the ring and body are ecjually dark."

.\n impression has prevailed that the forty-feet telescope
rather disappointed expectation, and that its defining powers
were certainly not on a par with its light-grasping capacity ;
at any rate Herschel generally used the twenty-feet and seven-
feet instruments. Burnham's opinion is that some of the
instruments utilized by the old observers of double stars could
not compare favourably with modern refractors, and particu-
larly with telescopes made by the Clarks. " Even when the
earlier observers had powerful instruments in point of light-
gathering power, as in the case of the Herschels, there can be
no doubt that they were far inferior in definition."

In the Phil. Trans, for 1795 he gives ns an idea of the
number of instruments made, and says : — " When I resided at
Bath I had long been acquainted with the theory of optics and
mechanics, and wanted only that experience which is so
necessary in the practical part of these sciences. This I
acquired by degrees at that place . . . My way of doing
these instruments at that time, when the direct method
of giving the figure of any of the conic sections to specula was
still unknown to me, was to have many mirrors of each sort
cast and to finish them all as well as I could ; then to select by
trial the best of them, which I preserved ; the rest I put by to be
repolished. In this manner I made not less than two hundred
seven-feet, one hundred and fifty ten-feet, and about eighty
twenty-feet mirrors, not to mention those of the Gregorian
form."

High magnifying powers involve a severe test of the perform-
ance of telescopes. In proof of the quality of his mirrors we
may quote him as saying " In beautiful nights when the
outsides of our telescopes are dripping with moisture dis-
charged from the atmosphere there are now and then
favourable hoars in which it is hardly possible to put a limit
to magnifying power."

But these superlative hours were all too few-, alas, for he
mentions he " had recourse to his journals to find how many
favourable hours we may annually hope for in this climate.
It is to be noticed that the nights nuist be very clear, the
moon absent, no twilight, no haziness, no violent wind, and no
sudden change of temperature, and it appears that a year
which will afford ninety or at most one hundred hours is to
be called a very productive one."

Herschel's favourite working instrument seems to have
been a seven-feet of six and three-tenths inches aperture.
Speaking of observations of Saturn he mentions that "all that
magnifying can do may be done as well with the seven-feet as
with any larger instrument."

The great forty-feet telescope was not used very frequently
by Herschel, as its manipulation occupied valuable time and
required assistance. It has been stated that this large
instrument was discarded in consequence of its bad perform-
ance and cumbersomeness, but this is scarcely justified.

244

Junk. 1911.

KNOWLEDGE.

245

Herschel himself states " A forty-feet telescope should only be
used for examining objects that other instruments will not
reach." "The opportunities of using the forty-feet are
rendered very scarce." On August 28th. 1789, he says
" Having brought the forty-feet to the parallel of Saturn.
1 discovered a sixth satellite of that planet, and also saw the
spots upon Saturn better than 1 had ever seen them before, so
that I may date the finishing of the forty-feet telescope from
that time."

This is great praise for the big instrument, but Dr. Dick in
describing the details of its construction and worl<, as published
in the Phil. Trans., says: " It was not to be expected that a
speculum of such large dimensions could have a perfect
figure imparted to its surface nor that the curve, whatever it
might be, would remain identically the same in changes of
temperature ; therefore we are not surprised when we are
told that the magnifying powers used with this telescope
seldom exceeded two hundred ; the cjuantity of light collected
by so large a surface being the principal aim of the maker."
The Practical Astronomer, Page 304.

No doubt Herschel's object was chiefly to get as much light
as possible out of his instruments, as he was constantly
searching for faint nebulae, minute satellites and so on.
Thus we often find him adopting contrivances, and using
expedients to obtain the maximum " penetrating power."

Possessing optical and mechanical sicill only matched by-
unwearying energy, Herschel must have succeeded in pro-

ducing some thoroughly good instruments, though it should
never be forgotten that his splendid ob.scrvational work more
indicates the measure of the man than the particular kind or
quality of his glasses.

We, at the present day, cannot fairly judge as to the degree
of perfection he attained, but it certainly ni'ist have been
considerable. Critics may possibly find fault with a few details
recorded in his papers, in the volumes of the Phil. Trans.,
such as the supposed discovery of the ring around Uranus, but
when we consider the enormous amount of work he accom-
plished, sometimes in indifferent air, or amid trying circum-
stances, he must have been more than mortal could he have
invariably avoided mistakes.

Herschel's papers number sixt>'-nine, and they are practically
inaccessible to the general astronomical pulilic, in the volumes
of the Phil. Trans. Will these important memoirs ever be
reprinted in book form ?

Every year brings us some new astronomical works, but
they are neither so welcome nor so valuable as a volume of
Herschel's writings would prove. And this has been a
desideratum for more than a century 1 Had Herschel's
collected papers been available for convenient reference what
immense trouble would have been avoided, and how many
misunderstandings prevented ! Some descendant of the
illustrious astronomer should present the scientific world with
a handy volume of his results described in his own language.

SOL.AR DISTL'RB.VNCES UURIXG APRIL, 191 1.
Bv FRANK C. DENNETT.

There has been a continuance of the somewhat increased
activity upon the solar disc. On three days, April 18th, 19th
and 20th, no disturbance, bright or dark was visible ; and upon
the 16th and 17th only bright, or faculic disturbances were
seen. At noon on April 1st the longitude of the central
meridian was 188° ib' .

No. 12 on the March list continued upon the disc until .Vpril
6th, and therefore re-appears upon the present chart.

No 13. — Near the eastern limb, on the 1st. there appeared a
moderate spot, but when farther on the disc it was seen to
consist of three spotlets and three pores in slightly divergent
lines. The middle, largest spot had the inner edge of its
penumbra fringed brightly. The members decreased from
the 6th until the 8th when only penumbraless pores were
visible having a faculic lip. The length of the group was
44,000 miles. The region was faculic until the limb was
reached.

No. 14. — A spotlet. only seen upon the 2nd.

No. 15. — A pore, only visible upon the 4th. approximately
in the position shown.

No. 16. — A solitary spot, 10,000 miles in diameter, crossed
tte disc between the 3rd and 15th. The inner edge of its
penumbra was fringed bright upon the Sth. 10th and 12th.
whilst the umbra was crossed by a bridge upon 12th and 13th.

.No. 17. — A spot, 14,000 miles in diameter, visible from April
22nd until May 3rd. The penumbra brightened inwards upon
the 24th, 26th, 27th, 30th, and May 1st, and the umbra was
crossed by a bridge on the 24th, and from the 27th until the
30th. On the 2Sth and 29th the southern half of the umbra
appeared to be less dark than the northern.

No. 17(7. — \ fine spot 15,000 miles across, visible from
.4pril 22nd until May 5th. The brightening inwards of the
penumbra was noted on the same days as No. 17, and also
on the 26th. The umbra was ci"ossed by a bridge w-hich
became very narrow. .\ faculic chain, convex northward,
joined Nos. 17 and 17a, in which evanescent pores appeared
on the 28th and 29th.

No. 176. — A spotlet seen from the 22nd until May 2nd.
There was a bright inner fringe to the penumbra on the 24th.
On the 27th the umbra became elongated and on the 28th and
29th broken. Pores showed round it on the 27th, 28th, 29th,
and on May 1st.

No. 17c. — Two spotlets upon the 24th. one remaining until
the 26th.

No IS. — A small group of pores only seen upon the 30th.

The chart is constructed from the combined observations
of Messrs. J. McHarg. A. A. Buss, E. E. Peacock, and E. C.
Dennett.

DAY OF APRIL.

If

If

}

12

11

1

0

?

?

S

5

«

5, P

2 i

9 1

28

V

^«

^f

^*

->

!

'^

21

2t

9

IS

17

(3

30

Ifi

18

vi

12

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Eq

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20

30

N

'e'

30

N

13

(5

/4

FCO

1

0 2

0 3

0 4

0 5

0 6

0 7

0 8

0 9

0 l(

3 1

0 1

'0 1

0 1

0 1

0 1

0 1

•0 1

)0 ]

K 2

M 2

0 2

20 2

30 2

^ 2

SO 2

50 2

'0 2

30 2

90 3

00 5

0 3

?0 5

50 3

,0 3

iO i

)0

NOTICES.

LEWIS'S CIRCULATING SCIENTIFIC
LIBRARY.— We have received from Mr. H. K.
Lewis, of Gower Street. London, a sup[)lementar\-
catalogue, covering works added to the hbrarv during
the years 1908 and 1909. The catalogue is published
at si.xpence, ' and contains a classified index of
subjects with the authors who have written upon
them, as well as an alphabetical list of titles. We
have on pre\'ious occasions called tlu' attention of
our readers to the completeness of this librarw and
the inducements it offers to students of science.

be produc(-'d Iw them in rooms, while the other shows
how electric it\- can be pressed into domestic service.
Our illustration shows one of the demonstration
rooms. Beginning on the extreme left we find that
the first ceiling light illustrates the method of down-
ward reflecting b}' means of an opaque reflector. The
second shows one in which there is a white silk
shade beneath the lanii> to diffuse the light below and
produce upward reflection. The fourth, with the
bell-shaped shade, illustrates a method of concentrat-
ing all the light and reHecting it downwards. The

1 >riiii initiation Roimi at the Westminster IHectric Supply Corperation.

Mr. Lewis has asked us to mention that bis premises
^\•ill in future be closed at 6.30 p.m., instead of
7 p.m., during the months of June, July and August,

A NEW DISCOVERY.— Smoked glasses, it has
been shown, onlv cut off a part of the ultra-violet
ra\s, which are those which have an irritating effect
on the eyes of man}- people ; they also are harmful
as they make the retina more and more sensitive to
light. A new glass which has been called "Spectres "
has been introduced by Messrs. W. Watson & Sons,
of High Holborn, which cuts off the ultra-violet rays
and yet allows all the remainder to pass freely. It
has a pale green tint but it is the chemical con-
stituents upon which its p(;culiar properties depend,
and eye-glasses made from it have not the disfiguring
effect of the ordinary smoked ones.

ILLUMINATION.— A very interesting exhibi-
tion is now open at the offices of the Westminster
Electric Supply Cor[)oration, Limited, in Ecclestone
Place, Belgravia. One part of it deals with \arious
systems of electric lighting and the effects which can

hith shows upward reflection anel slight downward
diffusion by means of an opal shade. The seventh
gives diffused light by means of holoj)hane glass.
The effects of lighting by means of tnetai filament
lamps hidden behind the cornice are also well seen.
The candle lamps are used for reflecting from the
walls, and the brackets below them are intended for
downward lighting.

On the other side of the exhibition we have an
elaborate display of the apparatus which is being
perfected in connection with cooking b\- electricity,
and an experienced cook is in charge to demonstrate
its use. Amongst the exhibits are ranges, ovens,
grills, breakfast cookers, kettles and apparatus for
giving continuous hot water supply at very small
cost. There are also methods of introducing warm
fresh air. for keeping towel rails sufficienth' hot to
air the towels, and motors for working sewing
machines and floor polishers as well as soldering
irons, hair driers, and curling tongs which are
themselves heated Iw tlie current as the\- are used.

J46

Knowledofe.

With which is incorporated Harduiclce's Science Gossip, and the Illustrated Scientific Xews.

A Monthly Record of Science.

Conducted by Wilfred Mark Webb, F.L.S., and E. S. Grew, M.A.

J L' L Y , 19 11.

PLAXT HAIRS.

By K. i:. STVAN.

(Cuntinucd truiii Page 766.)

III. — Branched and StiX(;iN(; Hairs. ornamented with munerous lateral brandies, which

(eft Thi-: term "compound" is applied to branched are long and very slender, giving the appearance of a
hairs, their distinctive feature being that the\- gi\'e person holding up many arms. .Again, in the Deadly

Figure 1.
Hair from the leaf of Garden Rihcs.

Figure 2.

Hair from the corolla tube of
Deadly Nightshade.

Figure 3.

Hair from the leaf of the Chili
Nettle iLoasaK

off lateral branches from the main pedicel instead of
from the tip, as do forked hairs.

Among the branched hairs are all kinds of most
extraordinary-looking structures, and man\" of very
great loveliness.

If we examine a hair fnmi the leaf-shcatli of
garden Rihes (see Figure 1) we lind that the main
pedicel is more or less thick all its length, and
distincth" swollen at the base, glandular-tijjped. and

Nightshade (see Figure 2), a most strange form of
branched hair may be found, consisting of a number
of thick, clumsy-looking cells, fitting into each other
at all sorts of awkward angles, which create an
impression of a hand with fingers pointed out
and dow n. or of some species of thickly-formed coral
from a foreign sea. Every part of this plant — the
stem, leaf-surfaces, veins, flower stems, calyx and
corolla surfaces, coroiia tube, stamens and stigma —

247

248

KNOWLEDGE.

JUI.V. 1911.

show these marvellous little hairs, and they are
indeed " things " worth looking at \ery carefully.

Figure 3 depicts
two hairs from
the leaf of the
Chili Nettle.
On this j)lant
t w o distinct
forms of hairs
are found: (1)
these branched
ones and (2)

'^^^

l-IGURE 5.
hair Iroin the Itaf

Figure 4.

Hair from leaf of Mouse-ear
Haukweed.

others of (juite different
form, that sting. No one
can deny that the branched
hairs are very formidable
looking structures, with their
barbs, or tinw sharp-pointed
branches springing out at
all angles from the surface
of the chief pedicel, which
is swollen at the base. A Slin,

hair like this reminds one
rather of the teeth of the swonl-lish. l-'igure 4,
illustrating a hair from the leaf of the wild Mouse-
ear Hawkweed, shows another branched hair, some-
what similar to that of the Chili Nettle {Loasa). but
different in that its apex divides off into two wee
brandies, and its lateral ones are thicker and less
tooth-like.

Perhaps Sfiiii^iii}> Hairs should be included amongst
the glandular, since the\- secrete a peculiar acrid
burning fluid, but they are so interesting that this
fact seems to warrant their being considered bv
themselves.

Two species of stinging plants have been chosen
by way of illustration (1) the Chili Nettle ^see Figure
b). (2) tile Common Stinging Nettle (see Figure 5)

Our own .Still
name from the

"Urticii" lieing derived from ina
individual hair of this plant shiiws a
bulbous base composed of a large number of elastic
cells, a long pedicel, and an oval, slighth' enlarged,
sharp-pointed "cap" at tlir tip. TJie cells at the
hair-base contain the gland that secretes the acrid
Huid. By means of a duct that runs up the pedicel,
this fluid is conducted to the tip of the hair, and, if
till- point of the delicate cap be luoken or pressed

against unwarily, the sharp point pierces the flesh
and the secreted fluid is injected. If, however, the
hair be damaged bclaic the cap. no uncomfortable
feeling is experienced because the stinging fluid docs
not then become injected into one's skin.

Our own English species of Stinging Nettles
are unpleasant enough to handle roughh'. but
some e)f the foreign species, especialK' i'rficu
buccifeiii and C Halcrica are most formidalile
plants. In some of the East Indian species thev are
truly dangerous for, after the first pricking sensa-
tion has passed aw aw it is often followed bv that
of hot irons being rulibed
on the flesh, and the pain
increases to such an extent
that, after hours and some-
times days, the patient is
seized with s\'inptonis like
those following influenza and
lock- jaw, whilst sometimes
death results — especialK' when
the stinging has been caused
b\" one species of nettle from
Java. Our own species never
prove in an\' wa\' dangerous,
merely discomforting at the
time and sometimes for several
hours afterwards. Another
plant — Malpighia iireiis — has
dangerous stinging append-
ages, and thev are met with
^i __ also in some species of Rhus.
An indi\'idual hair ol the
Chili Nettle (Loiisa) is
.f Willi Xrttl.-. luilbous at the base and

there secretes
its acrid fluitl
w h i c h r u n s
up the pedicel
duct to tile hail-
tip. In this
case. howe\'er,
unlike our own
nettle, the tip
is not swiillen
into a distinct

ing Nettle iUrtica) receives its
Inirnin.i,' iiroperty it possesses,
I burn. An
\'er\- enlar.t;ed

" cap

1) u t

is ver\' s

larp-

pointed, li

ke a

curved needK'.

These h

1 i r s

grow in

thick

masses, a

Ion g

with those

that

are branched, on

the lea\es

and

stems of

the

plant. In

l.,,tli

cases the

hail s

are p r o b

abJN'

defensive.

,Slint;iug

liair from tlie ieaf
Cliili Nettle.

THE GOLDSCHMIDT REACTION.

Bv H. STANLEY RKDGROVI-:. r>.Sc. (Lond.). F.C.S.

1. Scip;ntific Aspects of the Goldschmiht
Reaction.

It was ill 1N9S that Dr. Hans Goldschniiilt
announced that he had succeeded in reducing the
o.xides of many metals very conveniently by the aid
of aluminium^ That aluminium should pr<)\e a
most powerful reducing agent, readih' reacting with
the oxides of other metals with the [)roduction of
much heat, is a result that might ver\- well be
expected from the fact that aluminium has a greater
heat of combustion, and therefore possesses a greater
affinit\" for oxygen than the
majority of other metals.
But like certain other sub-
stances which, capable of
reacting e xotherm ically
(i.e., with the e^•olution of
heat) with one another.
will not do so until a cer-
tain amount of energy has
been supplied to them from
without, aluminium and
metallic oxides will react
with one another only at
high temperatures. Earlier
attempts, however, to
bring about the reduction
of metallic oxides In'
aluminium, by heating
mixtures of these in-
gredients, proved \'ery
unsatisfactory; for
either no reaction took
place, not sufficient heat

rr T

^yyyyyyM'/y:i^y/y/)'y>%y///^^^

to start it being sup-
plied, or else it occurred
with explosive \iolence.
Dr. Goldschmidt over-
came the difficult\ by an ingenious device.

FicruH 1.
\pparLitus employed by Weston and Fllis for carryin
"therniitic " reactions ;/; vacuo.

He found

The external heating necessary to start the reaction
may in some cases be supplied by means of a strip
(if binning magnesium ; or better, a fuse composed
ri- of aluminium powder and liarium

peroxide (which can be ignited by a
flaming vesta) may be employed.

I'rom the chemical standpoint the
reaction is one of the simplest, thus,
in the case of iron oxide it may be
represented by the following equa-
tion,—

FeoOa + 2 Al = AloO, + -' Fe,
— and similar equations can be con-
structed to represent the reactions in
the case of other metallic oxides. The
heat generated in the reaction between
aluminium and iron oxide is sufficient
to fuse both the alumina and the
metallic iron produced, the whole
contents of the crucible in which the
reaction is carried out becoming fluid.
The metal, owing to its density,
sinks to the bottom. The temperature
reached is second only to that of the
electric furnace, being estimated to be
about 3.000"C. The reaction can
be \er\- readily carried out, no
il)liaratus be\'ond a crucible of
h i g h 1 \' refractory
material being required.
Care, however, should
be taken to protect the
crucible in case it
should be cracked b\-
the heat of the reaction,
and its molten contents
run out.

That substances

out

apparenth' so inert as aluminium and iron oxide

that intimate mixtures of metallic oxides and powdered should be capable, once interaction between

or granulated aluminium, if heated strongly at one them has been started, of producing suffi-

point, react with the production of intense heat, the cient heat, not only to continue their own com-

temperature produced being far greater than that bustion, but to liquefy iron and even more difficultly

required to initiate the reaction. Consequently the fusible metals, may seem an extraordinary fact. But

reaction spreads throughout the whole mass, as a it is (juite analogous to the behaviour of a rock nicely

matter of fact doing so ver\- rapidly, the time of balanced at the top of a hill. Leave it alone, and

reaction, which is about half to one minute in the what could seem more destitute of energy : give it

case of iron oxide and aluminium, not appreciably but a gentle push — and who shall stay its course ?

depending upon the cpiantitv of material employed. r>y using other oxides in place of iron oxide

' H. Goldschmidt: " Ueber ein neues Verfahren /ur Darstellung von Mctallen und Legirungen niittelst .-Muniiniunis" .Aniujlcii

dcr Chcinic, (1898), Vol. 301., pp. 19 et seq.. and H. Goldschmidt and C. Vautin : " .'\luminiuin as a Heating and Reducing

Agent" Journal of the Society of Chcimcal Industry, (1898), Vol. 17, pp. 543, 649.

249

250

KNOWLEDGE.

JlI,Y. 1911.

Goldschmidt was able to prepare many other metals
(in a fused condition). Moreover, [providing that the
oxide was present in slight excess of the amount
chemically equivalent to the quantity of aluminium
emplo\ed. the corresponding metal was obtained in
a state of exceptional puritv. free from carbon. By
using mixtures of oxides. allo\'s of desired composition
were similarlv obtained. It seems, indeed, that
practicalh- all metallic oxides will react in this
manner with aluminium. In some cases. t'.,i,'..
titanium and vanadium, in which pure metals are not
obtained, the product is sufficiently pure for the
preparation of the chlorides. Even calcium oxide
(lime) is not entirely proof against the activity of
aluminium, though the reaction between these two
bodies can onlv be brought about when they are
heated together in a furnace, and is then by no
means complete. It seems, therefore, to differ from
the reactions between aluminium and other metallic
oxides in being endothermic (i.e., heat-absorbing),
and it mav be concluded that calcium has a greater
heat of combustion than aluminium (measured, of
course, with respect to the same quantity of
oxN'gen).* Magnesia, however, is quite imattack-
able b\' this most active element. With alumina
itself, aluminium \'ields a blackish-grey [)roduct.
[)robabl\" containing a sub-oxide.

Aluminium reacts in a similar manner with the
sulphides of the metals. Thus, with galena (lead
sulphide) the ])roducts are lead and aluminium
sulphide, as shown b\' the following eijuation. —

3PbS-K2Al = .\l.,S.,+3Pb.
This reaction ma)- be employed for the preparation
of aluminium sulphide t which cannot be obtained in
the wet wav, since it is decomposed b\' water, giving
aluminium hydroxide and sulphuretted hydrogen)
which is obtained pin^e if the ahuninum is present
in slight excess."'' This excess of aluminium also
serves to free the lead from aii\' metallic impuri-
ties, for \\hilst aluminium will not allo\- with lead.
it readiK' allovs with man\- other metals. If
aluminium were cheaper, the method might be
used commercially for the extraction of traces of
the precious metals from lead ores.

.Muminium will also react with certain non-
metallic oxides {e.g. boron trioxide and silica). In
the former case the product of the reaction
contains ahuninium lioride and aluminium nitride

(the nitrogen coming from the air) as well as
alumina and free boron.; In the latter case
impure silicon is obtained as a crvstalline substance
containing aluminium. Aluminium will also react
with charcoal : in this reaction the air seems to pla\-
an important part, the product containing aluminium
oxide and nitride, as well as aluminium carbide
(Al^C:,) together with unchanged aluminium and
carbon.!;

Since Goldschmidt's discovery. man\' other re-
actions, similar to those between aluminium and
metallic oxides, in which substances other than
aluminium are emploved, have been described. Dr.
F. M. Perkin, for example, has succeeded in bringing
about the reduction of metallic oxides and certain
other substances (e.g., galena and borax) by
means of metallic calcium. Dr. Goldschmidt has
also carried out experiments with this metal : he finds
that it reacts with oxides in a most violent manner,
but a regulus of metal is not formed ow ing to the
limited fusibility of the calcium oxide produced. He
finds, also. that, whilst silicon alone vields unsatis-
factory results, a mixture of calcium and silicon reacts
with metallic oxides in a satisfactorv manner. gi\ing
a fusible slag of calcium silicate.*^

Another substance. heha\ing in a similar manner.
is calcium hydride (CaHo). Dr. F. M. Perkin finds
that a mixture of this substance and cupric oxide
tin the proportion of two molecules of the oxide to
one of the h\'dride) can be readily ignited : volumes
of steam are evolved and copper is produced, but the
temperature is insufficient to melt the whole of the
copper. .A mixture of antimony sulphide and calcium
hydride is also \'er\' eas\' to ignite. .\s the reaction
proceeds, the mixture swells up in a manner similar
to that in which mercurv thiocvanate C Pharaoh's
serpents") behaves when heated.**

Messrs. F. E.Weston and H. R. Ellis have carried
out a series of experiments on " thermitic reactions '"
(as these reactions are called) /// vacuo. Their final
form of apparatus is shown in Figure 1. They found
considerable difficult\ in igniting the mixtures
experimented upon, but this was probably due to the
difficultvof producing a sufficientl}' high temperature
//; vacuo. They succeeded, however, in obtaining
reaction in vacuo between magnesium and sodium
peroxide and between aluminium and sodium per-
oxide h\ ignition with a platinum wire electricall}-

* F. E. Weston and H. R. Ellis: "The Heats of Combustion of Aluminium. Calcium and Magnesium." Transactions of the

Faraday Society, (lOOS). \'ol. IV.. pp. loO ct scij.
I In this reaction the mixture may be heated in a crucible furnace with the cover off: but the aluminium should not be too

finely powdered, as otherwise the heat generated may be sufficient to volatilise the lead. gi\ing rise to an explosion.
; F. i:. Weston and H. R. Ellis: " Note on the Action of Aluminium Powder on Silica and Boric .Anhydride," Transactions

of flic Faraday Society, 11907). Vol. III., pp. 170 et seq.
} F. !•:. Weslun and H. K. ICUis : " The Interaction of Aluminium Powder and Carbon," Tr,insactions of the Faraday

Society, (1908), Vol. I\\. pp. 60 et seq.
ii F. .\I. Perkin: " Reduction of Oxides, Sulphides. lS:c., by Metallic C:dciuiu." Transactions of the Faraday Society 11907).

\'ol. III., pp. 115 et seq.
• English P:itents, 7SH. Jan. lUh. I'JOO.
•■•" F. M. Perldn and L. PnUl : " Reducing Action of Metallic Calcium and Calcium Hydride upon Metallic Oxides. Sulphides and
Halogen Salts." Transactions of the Faraday Society (19071, Vol. HI., pp. 179 et seq.

Jui.v, 1911

K^

JUW

heated : and b\' the

use

of

the 1;

itt

.T

mix

ture

as a

fuse the\'

succeeded

in

obt;

ininR

re

ac

tinn

//; I

aciin

between a

luminium ;

md

u-oi

(ixidi.

I

1 air

one

drop

Figure i.

Titanium " tliennit " in foundry worl<.
iHcatinfj "thermit" tin nver the ladle before in^;ertion.l

of water added to a mixture of ahnniniuni and
sodium peroxide causes it to react : but //; vacuo tiie\'
found it to cause merely a sHght effervescence.*

II. — Tfxhnological Aspects of thk G()I,d-
scHMiDT Reaction.'

The technolo.i;ical importance of Goldschmidt's
reaction can hardly be over-estimated. The whole
subject is as yet in its infancy, but already it ma}- be
said to constitute a new branch of technologw to
which the name of " Aluinino-thermics " has been
given.

In the first place, the reaction serves for the
preparation of a number of pure metals and allo}-s
of considerable value in the iron and steel and allied
industries. Of the former of these we mav mention
chromium (98-99% pure), manganese (96°;,). and
molxbdenum (98-99%). Chromium is used in the
manufacture of high-speed tool steel, as well as
armour [ilate : manganese is also used in the
manufacture of very hard steel. Amongst the allo\-s
we may mention chromium-manganese, manganese-
titanium, ferro-titanium. ferro-\anadium and ferro-
boron. CLT"' P '!

251

"Thermit"; containing a small amount of titanium
oxide is used in foundry %\ork. The mixture, jilaced
in a tin fastened to an iron rod (see Figure 2), is
plunged into the molten iron as s<xm as it is run from
the furnace into the ladle, and held at the bottom until
the reaction is over. The slag rises to the top and can
be removed. It is found that this treatment tends
to prevent blowholes and to give clean, dense
castings, the effect of the titanium being to increase
the fluidity of the metal and produce a finer grain ;
moreover, the sulphur content is decreased.

In the slag from the reaction of chromium
'" thermit," minute rubies are found, ruby being
nothing but crystallised alumina coloured with
chromium : but they are too small to be of any
commercial value. A use, howe\er, for the slag has
been found. Dr. Buchner has discovered tliat, owing
to its comparati\-e freedom from metallic impurities
and absolutely anhydrous condition, it is preferable
t(> natural corundum (which it resembles) in the
manufacture of pottery, for which purpose it is
mixed with cla}- and burned, and is especialh- useful
tor making chemical apparatus which ma^• be
subjected to great changes in tiiuperature without
f r.irtiirni'' .

I'IGURE 3.

Aliimino-therniic repair to the stern frame of the
s. s. "Sexilla" after t\vel\e months.

■■■ F. E. Weston and H. R. Ellis; "Thermic Reactions in Vacuo." Trntisactions of flic Faraday Society, (1910), Vol. VI.

i The writer's heartiest thanks are due to "Thermit. Limited" for their kindness in supplying him with full

information concerning the technological applications of Goldschmidt's Reaction, for opportunity to examine their

apparatus and methods, and for the loan of the blocks of several illustrations in the present article.

, '■ Thermit " is the registered name given to a mixture of aluminium and iron oxide.

KNOWLEDGE.

Jri.v. 1911.

■■ Thermit " is also employed technologically as a butt-welding of iron pipes. The ends of the
heating agent. As Dr. Goldschmidt has pointed out,* pipes to be welded together are surrounded bv
in ■■ thermit" we have a new sort of fire differing a suitable luould. into which the products of the
in certain respects from all
other fires. In the first
place, in the combustion
of "thermit "' neither is air
consumed nor is anv gas
evolved, as in the case of
the combustion of such
substances as wood, coal,
coal-gas or petrol. The
second difference is in the
heat densitv. The actual
amount of heat obtainable
from a given weight of
"thermit" is realh" much
less than that obtainable b\
the combustion of the same
weight of anthracite: but in
the former case the \\hole
of this heat is, so to
speak, obtained at once,
the reaction between large
quantities of iron oxide
and aluminium, as we
ha\e already indicated,
occupying a \ery short
period of time : indeed, b\-
the combustion of "ther-
mit " a heat density is
pr(_)duced unattainable
otherwise. It is these

peculiarities m its behaviour which determine the to heat the lines to welding point, but the liquid
apphcaliihtx- of the " thermit " fire. Where a steel produced is emploved to form a bulb of metal
continuous heating effect rather than density of heat is holding the two lines together, thereby strengthening

the joint. An

Figure 4.
Aluiiiino-therniic weldint; of train rails.

■■ thermit '" reaction are
poured. Welding tempera-
ture being reached, the
ends of the pipes are
pressed together bv means
of screws arranged in
position beforehand. Of
course, if the liquid iron
jiroduced in the reaction
were allowed to come into
contact with the pipes.
the\" would be burnt
through, but it is found,
as a matter of fact, that
the highh-refractory alu-
mina slag, which issues
from the crucible first on
pouring out its contents
after the reaction, solidifies
on the surfaces of the
pipes, thus forming a
protective coating which is
impenetrable b\' the molten
metal.

In a method of welding
which has been chiefl\-
applied in the welding of
tram lines, not onl\- is the
heat deri\-ed from the
"thermit" re-action utilised

the essential de-
sideratum, "ther-
mit" would be
useless: thus it is
not suitable as a
source of heat for
locomotive pur-
poses or for cooking
generally. But
where great density
of heat is required,
" thermit " is pre-
ferable to other
forms of fire, be-
cause by its aid one
can so readily pro-
duce an enormou>
tem{)erature at a
moment's notice.

One of its chief
applications as a
h e a t i n

dv

!S

agent
in t h e

-Aliunino-thennic welding

Figure 5.
)f ''third" rails iParis, Metropolitan Raihvayl.

illustration of the
method in use is
shown in Figure 4.
The " thermit " is
ignited in a crucible
with a hole in the
bottom fitted with
a device for tap-
ping. The moulds
around the rails
are constructed in
such a manner
that the "thermit"
steel, which fir^t
issues fro m t h e
crucible when it is
tapped after the
re-action is o\-er,
r u n s to the
bottom, forming a
metal bulb over
the joint to al)out

H. Goldschmidt: " .Alumino-Thennics.- Transactions of the American Elcctruchcinical Society 119041. \'ol. \'I,

Part II, pp. S5 et seq.

July, 1911.

KNOWLEDGE.

253

half way up the rail or more. The metal, of course,
must not he allowed to come in contact with the top
of the rail. The molten alumina, which tlt)\\s out of
the crucihle after the liquid metal, completely covers
the top of the joint, and welding temperature
being reached, the rails are pressed together by
screws placed in position beforehand."

It is interesting to know that tests carried out on
rails thus welded have proved very satisfactory. The
following are given b\' the Manchester Corporation
Tramwaxs (November 29th. 1906).

BiiNPiNG Tests,

Loads
Span. E].istic Liinit

Rending
Moment.

tion of the welded edges of the rails to the high
temperature of the " thermit " reaction products has
no injurious effect upon the hardness of the rail.

.\ somewhat similar method to the above is
employed in welding third rails on ■,-iectric railways
(see Figure 5).

The liquid steel produced b\- the " thermit "'
reaction mav be employed in all sorts of repairs to
iron and steel articles : and not only is it applicable
to small articles but to work on the largest scale.
Indeed, bv the ignition of a couple of hundred-
weights of " thermit " one may produce in a few-
moments a hundredweight of super-heated mild
steel, a quantity producible in so short a period of
time by no other means. In repair work it is often
found advantageous to add a certain proportion of
steel punchings to the "' thermit " : this reduces the
quantity required and renders the reaction less violent.
As an illustration of the applicability of " thermit "'
to marine repairs we reproduce a photograph
(Figure 3) of a repair to a fracture (20-in. by 8-in.)
in the stern frame of s. s. "Sevilla"" of the Hamburg-
American Line, taken after twelve months use.

[We are indebted to Messrs. Thermit. Limited,
for the loan of Figures 2 to 5. — Eds.]

■'■ English Patents, No. 10,859, May 25th, 1901. (Dr. H.ms Goldschmidt : '■ .V new and improved process for welding metals.")
t These tests were made by measuring the lengths of indentations made by a hardened steel die with a curved edge struck to a

radius of one inch, and ha\ ing a cutting edge whose angle was 50°.

Solid Rail

... Ill Feet ...

2,S.200 ... 70,500

Fishplate Jointed

i:i\\ ... 10 1(1.001) ... 25.000

Thermit Jointed K

ail ... 10 ,. ... 25,000 ... 62.500

Solid R.ail

5 74,000 ... 92,500

Thermit Jointed R

■lil ... 6 42.000 ... 63.000

Harpness Tests'.

Load on Die

Welded Rail.

in Tons.

Length of Indentation Produced.

.-Vway from Joint.

Close to Joint.

0-25

... 6-26 Inch

0-26 Inch

0-50

... 0-32 „

0-32 ..

0-75

... 0-37 .,

0-36 .,

It is clear from

the hardness test

that the subjec-

UNIQUE AMERICAN STEAM

By FRANK C. PERKINS.

• R CAR.

During the past decade the steam motor car has been
developed to a high state of perfection in Europe, and has
entered the field of urban and inter-urban service with the
gasoline motor car, in com-
petition with electrically
operated motor cars. In the
United States, however, little
has been done in this line
until recently.

The accompanying illus-
tration shows a new and
unique car as utilised for
passenger service, provided
with a baggage compartment
and seats for thirty -eight
passengers.

.Although this steam motor
car was not designed for
freight service, its capacity
for hauling trailers or freight
cars in an emergency has been
demonstrated by hauling a
train of freight cars, weighing
fifty-two thousand pounds.

The car has a total length of
thirty-seven feet three inches
with a width of nine feet two
inches, and it weighs complete,
without passengers, sixty-six

thousand pounds. There is

included in this weight, six
thousand six hundred pounds
for water and oil, the latter
being utilized as a fuel instead of coa

Figure 1.

An Unique .American Steam Motor Car.

It is maintained that
this American steam motor car is capable of developing a

speed of forty miles per hour on a level track and is designed
for hauling not more than two trail cars or two express or
freight cars under normal conditions, although in emergency

longer trains can be handled.
It may be stated that the
engines are hung to the motor
trunk but the car body carries
the w-ater tube boiler which
supplies steam to the driving
cylinders at a pressure of 200
pounds per square inch.

The engines develop one
hundred and twenty-fi\e
horse-power and are capable
of driving the car at a speed of
forty miles per hour, with two
hundred pounds steam pres-
sure and on a level track. It is
maintained that the use of
crude oil for making steam is
most convenient in operation
and cleanly, there being no
dust nor dirt as when coal is
used and the combustion in
the fire box is complete.

While the primary object
aimed at. it is said, in the
development of this design
was to provide a self-con-
tained steam motor car for
passenger service, still con-
siderable freight and express
may be handled when neces-
sary, and a number of trailers may be hauled during heavy
passenger service on extra occasions when required.

Figure 1.
(rold Medal of the Rnval Astronnniical Society of London.

THE POLITICAL IMPORTANCE OF ASTRONOMY

AS A PEACE PROMOTER.

isx iki-:ne e. toye \\ak\i:k.

Member of flic British Asfroiioiitieal Associntiuii and nf the Soeiete Astn>iti)iniqiie de France.

There have been numerous conferences recently
to consider how best to promote international
arbitration and peace.

The study of geography and history on a wider
scale has been suggested,
but the vast and living
power of astronomy in
this matter has, as far as I
can learn, been practically
overlooked. It is to this
subject, therefore, that I
wish to draw specia
attention in this article.

Astronomy is pre-emin-
ently a living thing, ever
growing, changing, ami
advancing — requirin.i;
uniti-d and universal study.
More and more as time
goes on we find a tendency
towards cooperation
amongst astronomers
througiiout the whole
world. Racial and party
differences are at least
buried, if not wholly for-
gotten, in the study of a
science which deals with
other w orlds and universes.

Fig I- RE 1.
Bronze Comet Medal of the United States of Aineric.i.

and draws our thoughts from all that is earthl\-, to

consider that which is heavenh".

From its \ery nature, and the conditions necessar\-

for its fa\-ourable study, it is peculiarly fitted to play

a most potent part in the
promotion of universal
peace. Religion and
commerce are generally
acknowledged to be the
two greatest civilizers of
the world, but experi-
ence has shown that, in
the [)resent state of the
world's evolution, neither
has quite succeeded in
banishing war,

I do not for a moment
claim that w here they have
failed, astronomv would
succeed, but I maintain
that the latter must be-
come a great bond of union
between those \-ery
nations at present divided
b\- both religion and com-
mercial interests. This is
largeh' due to the fact
that astronomv can ne\er
become a means of mone\--

254

Jrr.v. 1911.

making or an object of greed.
No one %\ill ever be able to
claim the stars as an exclusive
possession. On the other
hand there is no tendency
towards socialism, for does
not "one star differ from
another star in glory " ? and
do not all the planets obey
their ruler, the Sun ?

Should not all who '■ con-
sider the heavens '" learn that
in them is universal peace
as a result of universal law
and order ?

There is nothing that binds
races or nationalities together,
promotes comprehension, and
fosters friendh' rivalry, like
having a common object of

KNOWLEDGE.

Figure J.

Janssen Medal of the Societe Astronomiciue

de France.

255

individual we honour the
nation to which he belongs,
and promote a kindly feeling
between the winner and donor
of the gift.

Other nations win our
medals and rewards, and we,
in our turn, receive theirs, the
onh- qualification necessary
being sterling worth.

Then, in the matter of
icork, heart\' and effective
cooperation is no longer
a dream but a reality,
amongst the students of the
heavenly science, for it is
an actual fact that in the
pursuit of astronomical
research and observation,
all nations, peo[5les, and

interest which appeals only
to the highest emotions with-
out exciting the baser passions
of mankind — and such, un-
doubtedlv. is astronom\-.

I do not think it is
generallv known that all
astronomical honours and
rewards are distributee
according to merit, irrespec-
tive of nationality. For
example, the Gold Medal of
the Royal Astronomical
Society is given to astro-
nomers of all nations and
creeds, and tongues, so long
as their merit is established
by the work they have done.
.\nd in thus honouring the

Figure 4.

One of the Medals

of the Societe

Astronoiuique de

I'rance.

Figure 5.
The Valz Medal of Paris.

languages are united.

Eclipse expeditions are
ever a means of fostering
amity between astronomers
(if different nationalities, par-
ticularly when the eclipse
happens to be visible from
some desert island where the
yarious members of the party
are throw n much together !

There is an International
Congress on the " Map of
the Sky." held at Paris.
This congress is composed
of seventy leading astro-
nomers, representing twenty-
two countries, scattered all
over the globe. These
"peace-promoters'" meet to

256

KNOWLEDGE.

Jn.v, 1911

To ([uotc the same ssveet singer (Mr. S. R. Lysaght)
" We are faithless of life, and
in creeds our unfaith do we
hide: the world that our faith
should unite with our creeds
we divide."'

It saw {)olitieal war, each

T7^ ~"^"',"^« party fighting for power and

/ ■ *i', "^1 proclaiming an immediate

-V- T-. ■ ■

"■^.M Uto[)ia if they gam it; and the

report the progress made in the preparation of an Paul ! . . . I of Apollos ! . . . I of Cephas '. " and

enormous photographic atlas of the hea\'ens. which onh' a small minorit\- who actually " li\e "' Christ.

was begun in 1887 and will not he finished tor

another ten years. On this

map o\'er forty million stars

will be marked, and when

complete it ^\ill represent the

combined work of astronomers

of nations otherwise divided

b\- race, creed, and commercia

interests.

Comets are ever a means
of promoting peace among'-t
widely separated nationalities.
A good example is furnished by
the "hairy star" discovered by
Mr. Morehouse, of America.
This comet in its Course passed
almost from the North to the
South Pole, and e.xhibited man\'
variations in form am
brilliancv. It was seen and
photographed b\- astronomers
at nearh' all the observatories
in the world and thus a com-
plete record of the histor\- of

this beautiful object was obtained Iw the united
efforts of the students of the heavenly science.

In its journey past this "little sun-lighted wanderer
in the depths of the Infinite" — as one of our greatest
living poets terms the Earth : — it saw many sad
sights. Fierce rivalry and doctrinal quarrelling
the \'arious sects, each cr\-ing " I am of

Figure 6.

Commemorative Medal of the Societe
.^stronnmique de I'rance.

universal struggle, and keen
competition of commerce ; yet
quiet, and apart from all the
turmoil of life, it found a
de\oted band of astronomers
whom no differences of creed,
nationality or interest could
deter from cooperation in
studying its gauzy, fairy-like
self!

Surely, then, if we teach the

nations even the elementary

truths of this great science and

gi\e them a common and united

interest in the starry realms, we lift their thoughts

hea\enward and appeal to those higher emotions in

the human soul, which e\er make iov peace. Let all,

then, who love science unite in striving to teach

its man\- lessons to the inhabitants of Earth, so

that in the fulness of time those that are "afar

oft" may draw near in unity, peace and concord.

SPRING AND .SUMMER .SHOOTING STARS.
Bv W. 1". DENNING. F.R.A.S.

I OBSfiRVED seventy-eight meteors in May, during watches
extending over twenty-two-and'a-half hours in the aggregate.

Very fortunately, this year one of the meteors was
seen by Mr. Fiamrnetta Wilson, at Reigate, and by myself
at Bristol, on May 24th. Details are given at the end
of this note, and I also give the real path of a bright long
meteor, recorded by the same observers from the radiant at
350°-f-37' on May 29th. This shower is a remarkable one
from the exceptional swiftness of its meteors in September.
The radiant being a long way from the earth's apex in that
month, we should expect onh' slow flights from it, but I have
recorded them as i^ery swift.

May meteors are very rarely abundant, but I found them
unduly plentiful on the 24th this year. Clouds \'eiled the stars
in the early evening, but a west wind cleared the sky at about
10.15 p.m., and the stars afterwards shone with a splendour
not often equalled at this time of the year. I saw eighteen
shooting stars in one-and-a-quarter hours.

July may be regarded as the advent of the meteoric
observer's prolific season. This month always exhibits a great
increase in the frecjuency of meteoric phenomena. At the
middle of the month the earth may be said to emerge from
the region of scarcity which she has been traversing since the
middle of December to enter a space far more richly
occupied with these tiny planetoids which illumine our
skies in the form of shooting stars. The first fortnight of
July usn.T-lly gives few meteors, but Perseids acti\'el\- durin.n

the last week. .4n observer may sometimes count twenty
or twenty-fi\-e meteors per hour and more than three times
the number ordinarily visible in the spring months of the year.
It is to be hoped that, as the heavens will now for some time
present such an abundance of meteors, many observers will
specially watch for them and record details of all the brighter
objects. It is important this work should be performed for
the purpose of securing duplicate observations, of the same
objects, at two stations. Without these data it is often difficult
to ascribe the correct radiant points and the real paths cannot
be determined.

Real Paths of 1

'wo Meteors Obse

RVED AT Reigate

AND Bristol.

Date

Mav 24

May 29

G.M.T

10" 38'"

10" 42'"

Radiant

243+34

350=" + 37°

Mag. of Meteor

3-2

3 - 1

Height at First

72 Miles

74 Miles

Height at End

53 „

57 „

Length of Flight

20 .,

yi „

Velocity per Second.

35 „

30 „

Position over —

Beginning

1 6 Miles N. of 1
1 Southampton j
1 4 Miles N.E. of 1

E.

of Northampton

Ending

I Netley \

Salisbury

N.ime of Meteor

i Coronid

I .'\ndro[uedid

AN ANTEDILUVIAN ZOOLOGICAL GARDEN.

Bv DK. ALFRED GRAUEXWITZ.

Though no human fanc\' could imagine the infinite
variety of forms embodied in the representatives of
the animal and vegetable kingdoms — either of which
is known to number hundreds of thousands of
different Sfiecies — an even superficial glance at the

I'liU'RL 1. Sfi_iiiisiin n(s .\-<>,u\rd bv Cci'iiti>s,Tii rii\.

fossil remains of extinct organisms shows that
Nature in the "course of bygone ages has brought
forth many startling forms to which
no analogy is to be found in our
present vegetation or fauna.

Carl Hagenbeck. the founder of
the famous animal park at Stellin-
gen, near Hamburg, where even
the most savage beasts are kept in
a state of apparent freedom, has
installed in his Garden of Eden a
series of wonderfully life-like repre-
sentations of the most striking
monsters that inhabited our earth
in prehistoric times, thus creating
what mav be called an Antediluvian
Zoological Garden. These weird
giants, who millions of years ago
ruled this world of ours, can be
seen in surroundings corresponding
to their verv modes of life, thus
producing a perfect illustration of
what the earth looked like in their
days. In fact, an hour spent in
that strangest of all sceneries brings

us back as in a dream to a world which the

science of palaeontology allows us to reconstitute in

its very details.

In that long-distant past the struggle for life among

the animal dwellers on earth must have been much
more acute than even now. A per-
petual \\ar was waged betw een those
monsters, startling alike by their
form and enornious size. The mani-
fold natural weapons which Nature
had lavished upon them proved no
sufficient protection in the course
of time, the more so as the chang-
ing climatic conditions sealed their
final doom to extinction. Apart
from such features as are entailed
by the peculiar conditions of their
antediluvian world, these animals
certainly ha\e much in common
with existing species, their remote
descendants, and strikingK- illus-
trate the slow evolution from one
class to another, with man^■ inter-
mediate stages between reptile
and bird, fish and mammal, and
so on.

These a n t e d i 1 u \' i a n cement

models, made in artistic perfection

b\- the well-known animal sculptor, Mr. J. Pallen-

berg, have been arranged in an impressive group

Figure 2. AUoSiitints feeding; on the remains of a Brontusaiinib

257

258

KNOWLEDGE.

Jui.v. 1911.

round the shores of a beautiful httle lake encom-
passed by abundant \'egetation. Most of them
are seen standing b\' the water's edge amidst the
shrubs and trees, while huge crocodiles and weird
creatures emerge from
the lake itself. Scenes
of battle between these
monsters of bvgone ages
lend additional realism
to their apjiearance.

Ever\- care was taken
to investigate most con-
scientiousK' all the bone
finds and fossil iiuprints
housed in. the foremost
museums of the world,
especially the American
j\I u s e u m of N a t u r a 1
Historw Each model
was submitted to the
leading authorities in the
science of palaeontolog\-
who, w herever necessarw
suggested such altera-
tions as might produce
a perfect agreement w ith
scientific data.

A fascinating scene of
battle offers itself to the
observer's e\e as he
reaches the bridge
crossing the lake (see
Figure 1). A monster
called C c ru t osd II r ii s
which could tie described as a crocodile with huge
kangaroo-like hind-legs and tail, is seen assailing
another beast of the reptile class, the Stc;^osaiii iis

which, though protected b\
or spines up to a \ard
of its l)ack. antl In
likeK t(j have been too cl

double row of plates
11 length down the centre
spikes upon its tail, is
clums\- in the long run to
resist the attacks of its
more agile, though con-
siderably smaller, eneni)-.
A short wa\' off is seen
an even much lartrer

g\a.nt.Ci\\\e<iBroiit()saiinis

^^^r (see Figure 2) wno lias

^^m. already succumbed in the

4^p^ struggle for life.

"'^^ An Allosaiinis. like-

wise a huge lizard of the
same faniih- of monsters,
is gluttonously dex'ouring
the remains of his luck-
less herbivorous fellow,
who apiparently was quite
untitted for an\' serious
struggle. The trium-
phant dinosaur with its
huge head and large
pointed teeth — as evi-
denced by the circum-
stances under which its
remains ha\e been found
— was one of the rulers
of those times, and
thanks to its enornious
I ore -claws, so well
iidapted for lacerating, its
powerful long hind-legs,
so admirabh- suited for jumping, was excellently fitted
to pla\' a domineering part. The dinosaurs, generalh'
sjieaking, constituted a family of land-dwelling

Figure 4. Diplndocus cnnw^ici.

Jl-lv, 1911.

KNOWLEDGE.

259

reptiles with an astounding abundance of forms
which are the more remarkable as the structure of
their skeletons giv-es evidence of a continuous
transition to the bird class of animals.

One of the largest among these monsters, beside
which the surrounding trees look small indeed, is a
giant Iguanodon (see Figure 3), the head of which
towers some twenty-five feet above the ground.
This weird creature habitually walked on its bird-like
hind legs as proved by the enormous foot-prints up

possessed a tropical climate and included e.xtensive
lakes of salt water, the sedimentary remains of
which form the "bad lands" of our day. The
Diplociociis. sixty-six feet in length, at the Stellingen
Park, has been reconstituted from the most complete
and not from the largest bone finds of its kind.
This mammoth lizard possessed a tail even longer
than the Iguanodon. while the hind-legs were not
much longer than the fore-legs, thus enabling the
beast to use all four limbs for walking about. The

FlGL'KE 5.

Rhinoceros Saurians.

to thirt\' inches in length and forty-five feet apart
which have been found in the weald of Sussex.
The erect position and bird-like gait of this beast
was assisted by the extreme bulk of its tail : the
neck w as relativelv long, the arms short and the first
and fifth fingers stood out nearl\- at a right angle to
the three middle fingers. However, the head was
surprisingly small and this limited provision of brain
ob\-iousl\' failed to protect the Iguanodon in its
struggle for life.

Another dinosaur species, the Diplodocus (see
Figure 4) bears a certain resemblance to the former,
but is of even hugcr dimensions. This animal
lived in W\oming. Montana. Colorado, New
Mexico and the Dakotas, which countries then

enormous length of the neck and remarkable
smallness of the head are equally striking.

Between the place where the Iguanodon stands,
and that reserved for its fellow, the Diplodocus,
visitors can watch a charming id\li of ten million
vears ago (see Figure 5). A family of " rhinoceros
Saurians" (Tricerafops) has come to the lake, and
the father lustily disports himself in the water from
which only his head and shoulders are seen to
emerge, while the mother with her little one still
lingers at the water's edge. Apart from the thick lizard
tail, characterising them as reptiles, these strange
animals strikingly remind us in general appear-
ance of the rhinoceros of our day. The Tricerafops
had three liorns, a beak like a bird of prey,

260

KNOWLEDGE.

July, 1911.

and a broad-toothed frill surrounding its neck.
An even more ancient group of fossil lizards com-
prises the Plesiosijtinis (see Figure 6). which could be

with their broad snouts and some RIiamphorhyiiLinif:
\\ ith long rat-like tails. On a mighty rock towards
which the Diplodocus is taking its course there are
represented two giant flying dragons in a lazy creep-
ing position and with striking life-likeness (see Figure
7). These Pteranodons, as t\\e\ are called in science,
were huge, short-tailed flving lizards endowed w ith a
long marabou beak and a narro\\ crest of nearh'
equal length at the back of their head.

Simultaneoush' with the now extinct animal
families, there lived many other species which are
more or less closely related to the reptiles of the
present daw Some specimens of these are the big
and small crested lizards < Diinctmdon ■dndXaosaiinis )
represented in Figure 9. While resembling in their
outward appearance an alligator endowed with an
especially large and broad snout, the\- were character-
ised by a high crest a\ ith rigid spikes running alongside
their back.

Two real crocodiles from the Cretaceous and
Jurassic formations, which are mainl\- distinguished
trom present-da\- rejiresentatives of the same family
by their clums\' build, are shown half hidden in the
water (see Figure 9). On the turf are seen creeping two
huge turtles characterised by a cartilaginous formation
on the tail and head, and especiall\" by two large
horn -like excrescences near the ear.

In addition to antediluvian rejitiles, there are

I'lcsiosaiini.s.

described as an c-normous seal with long, thickened
tail, remarkably lotig neck and a tiny head. It was
a marine reptile with limbs reminiscent of whale fins,
with fi\-e toes and no claws. A somewhat related
famil)- comprises the fish-like Ichthyosauria which
among the reptiles of their age occupied a similar
position to the whales among present-da}- mammals.
Their neck was short and stumpy, their snout
remarkably large, the tail lengthy and vigorous, and
the limbs as short as whale fins. Such an Ichthyo-
saiinis is seen (see Figure 5), in the lake to emerge
from the water with the swift and elegant motion of
a first-class swimmer, allowing the head, the front
half of the back and the rear fin to be seen.

Like these whale-shaped reptiles, the fossil flving
lizards or Pterosauria have left no representative
among the reptiles of our day. In fact, the onlv

analogy in our present-day fauna could be found w ith ' ^^

the bat family of the mammal class. However,
while the flying membrane of bats extends between
the second, third, fourth and fifth fingers and the
body, that of the Pterosauria reached from the
strikingly developed last (fourth) finger to the body.
The first three fingers were short and fitted \\ith
claws. A number of these strange beasts are seen in
the Stellingen Park, squatted at the water's edge,
crawling on the rocky shore, or resting on its stone

' ciosiiiiriis

slabs. These bird-lizards comprise a few /l

found some fossil animals belonging to other classes.
Quite a number of primitive birds (Archaeopteryx)
(see Figure 8), which are still closeh' related to the

July, 1911.

KNOWLEDGE.

261

reptile class, are seen roosting here and there on the
rocks and at the water's edge. The birds are
characterised by a long tail, consisting of vertebrae,
to which the large steering
feathers are fastened in a
ro\s' on either side. The
wing comprises three well-
developed fingers, while
some real bevelled teeth
are still found at the edges
of the jaws. Kciiiains and
imprints of Arclujcoptcryx
ha\'e been unearthed at
Solenhof, Germany, in
the lithographic slate of
the Jura formation. From
the middle of the lake is
seen to emerge the mighty
head of a batrachian.
called M d sto do n sa ii r it ,s ,
which was a member of
a famih' common to the
coal and trias formations.
While the largest amphibia
of our da\' hardh' reach
o n e - a n d - a - h a 1 f m e t e r s
length, these antediluvian

ancestors of theirs comprised some species, whose
skull alone measured one-and-a-half meters in
lenijth.

Another amphibian is the Pai'eiosaurus,
about two meters in
length, seen half-hidden in
the shrub, which can be
described as a giant toad
endowed with a short, blunt
tail, and a head relatively
narrower and less flattened
than that of present-day
toads, the skin showing
striking remains of bony
armour plates.

Even a fossil insect, viz..

a giant dra.

;on-

rds

■7

fly of up-

feet wing

represented at

en Park (see

of
expanse, is
the Stellinj.
Figure 9).

Elaborate plans have been
made for extending this
antediluvian "Zoo" by the
addition of a number of new
specimens belonging to all
the known extinct animal
taniilies.

<!»r ■

m^^.

r ^:^^\

Figure 9. A collectiuu uf .\iitediluviaii Reptiles,

RADIO-ACTIVE RECOIL.

I'.v WALTER MAK()\M:k. M.A.. D.Sc

It is well known that when a shot is fired from a
cannon, the latter attempts to move backwards and
is said to recoil. Furthermore, if the cannon is free
to move, then its velocity is such as to make the
momentum of the cannon equal to that of the
shot which causes it to recoil. The momentum
of a body is a quantit}' which juay be taken as
giving a measure of the (]uantit\' of motion
in a s\'Stem and is measured hv the product of
the mass and velocity of the body considered.

The question whether the ordinary laws
of dynamics apply to the case of atoms
as well as to that of molecular masses has
frequently been discussed, but till recently
it has been be\ond the possibility of direct
experiment to test the point. By the
recent discoveries in radio-activit\' the
motion of streams of atoms, and in some
cases of single atoms, can be observed

^

FiGU

RE 1.

and studied
afforded of
in motion,
radio-active
changes in
cerned, and

and

the possibility has thus been
the dynamics of atoms
It is now generallv accepted that
processes are the manifestations of
the constitution of the atoms con-
are of a more subtle nature than

chemical changes, in which atoms of various kinds
react on each other without affecting the internal
structure of the atoms themselves. Thus to take as
an example the case of the best known
radio-active substance — radium, discovered
by Mme Curie. It is now certain that
this element, which is similar to barium
in its chemical behaviour, is slowly but
constantly ejecting positiveh- charged
atoms known as n particles which have
been shown by Rutherford and others
to be nothing other than charged atoms

helium. This can be proved by collecting the
« particles, which can be detected in many ways and
then subjecting them to spectroscopic analysis. The
remainder of the atom from which the helium has
been expelled constitutes a new element also dis-
playing radio-active properties, which happens to be a
gas, and is called the emanation — a name which has
persistedsince the time of its discovery, when its nature
was not yet fully understood. The emanation, w hose
chemical and ph\-sical projierties are entirely distinct
from those of the radium which produced it, in turn
gives off a particles, and disintegrates into a new-
product which has been called radium A. The only
essential difference between this change and that
undergone by the radium exists in the difterence in
the speed of the disintegration. Whereas radium
takes tlK)usnnds of \ears to change into the

emanation and helium, the emanation is much more

unstable, and disappears in the course of a few weeks.

A similar process occurs with radium .\, which in

turn gives rise to a series of successive radio-active

products, known as radium B, radium C, and

so on. It should here be mentioned that all

radio-acti\e {processes are not exactly of the nature

just described: for in some cases the disintegration

is associated merel\' with the expulsion of an

electron — that minute negatively charged particle

- first detected by J. J. Thomson. It will.

however, be sufficient for present jnu-poses

to confine attention to those transforma-

t| tions in which the radio-active change is

— ' associated with the expulsion of an a

particle, which we have seen is a charged

atom of helium.

The change of radium .\ into radium B,

mentioned above, presents a particularly

convenient case for stud\ing the phenomena of

atomic recoil: for radium A has a very short " life."

and quickly disappears with the production of radium

I), an (1 particle being ejected during the process. The

details of the method of obtaining pure radium .\

from the emanation need not be considered here :

suffice it to sa\ tliat if a plate is exposed to

the emanation for a short time, as the kathode

in an electric field, it becomes coated with a

strongly-acti\e film of radium A. If the

plate is removed from the emanation and

left for some minutes, most of the radium

.A w ill have turned into radium B in position

and after about a quarter of an hour prac-

ticalh' no atoms of radium A will be left.

It is to be noticed tliat the radium B formed

remains on the plate. The thing is different

of when the experiment is carried out //; vacuo, for

according to the laws of probabilit}' half of the

number of a particles ejected will be shot out from

the radium A atoms awa\' from the plate and half

towards it. Thus in half the disintegrations of the

radium A when an « particle is shot into the plate,

the residual atoms of radium B possess momentum in

directions away from the plate and will be detached

unless there is some force preventing them from

leaving. When the experiment is performed under

ordinar\- conditions at atmospheric pressure, the atoms

radium 15 are prevented from tra\'elling more than of

a fraction of a millimeter before colliding with

molecules of air h\ which the\' are stopped : they

then mostly diffiise liack to the plate from which

they came. On the other hand, //; vacuo there is

nothing to stoj) the motion oi the' atoms of radium B,

and the\- continue on their course until tln'\-

262

July, 1911.

KNOWLEDGE.

263

encounter some obstacle such as a second plate
which may be placed at any convenient distance to
catch them. The plate receiving the recoil may
subsequently be removed and actuall\' found to be
coated with a deposit of radium B by testing in the
usual manner with an electroscope.

The same thing mav be accomplished in a some-
what different wa\-. as was first shown b}' Hahn,
b\- working at atmospheric pressure with an
electric field as shown in the accompanving diagram
(Figure 1).

The positiveK' charged plate A. coated with radium
A. is placed below the plate B which is negatively
charged and insulated from the plate A. After a
suitable exposure the plate B is remo\ed and found
to be coated with radium B.

Whichever mode of experimenting is adopted, it
will be seen that the method of recoil affords a con-
venient means of separating a radio-acti\e product
from the parent substance from which it is formed,
and this is perhaps the most important practical use
to which these phenomena have been put. Indeed
the method has alreadv rendered great service in
this direction, and its application has resulted in the
discover\- of new radio-active products.

To take two examples of particular interest which
were first investigated bv Hahn. It is well known
that thorium possesses radio-active properties similar
to those of radium, and gives rise to a number of disin-
tegration products. In particular, at one stage of the
transformations a gaseous emanation is formed, which
was known to produce successivelv three radio-active
substances — thorium .\. thorium B, and thorium C.
It was, however, unknown what became of the last
of these products after disintegration. By using the
method of recoil, it was shown that a previously
undiscoxered product was formed which was called
thorium U. A similar case is that of radium C.
which produces a series of slowly-decaying radio-
active products. Bv exposing a plate to the recoil of
radium C, a new substance has been isolated, which
has been called radium C, to distinguish it from
radium C. from which it is produced. The nature
of the recoil has quite recently been studied by
Fajans, and it would seem that, from the results so
far obtained, an entireh" new t\pe of radio-active
process is invoh'ed : but it is, perhaps, somewhat
earlv to speak with absolute certainty on the matter
as yet.

To turn again to the question of the dynamics of
the atom, which we have seen can be studied in the
case of radio-active recoil, and which has been
subjected to experimental test hv Russ. E\ans, and
the author. It has been mentioned that when the
radio-active atom breaks up with the expulsion
of an a particle, the residual atom recoils in
such a wav that its momentum is the same
as that of the a particle. Now a charged
particle in motion has been shown to act in manj-
ways as an electric current, and will therefore be
acted on by a magnetic field, just as is the case with
a wire carrying an electric current. Moreo\er. if

the particle is caused to move through a strong
electric field applied at right angles to the direction
in which it is travelling, it will be deflected from its
course. This has been shown to be the case with
(I particles, and the same should be the case with a
■■ recoil-stream " if this should prove to be charged.

Now the magnetic deflection depends upon the
momentum of the particles, and therefore the
deflection of the n particle and recoiling atom in a
magnetic field of given strength should be the same
if thev carr}- the same charges. On the other hand,
the electric deflection of the recoiling atoms should
be greater than for the a rays, since this deflection
can be shown to depend on the energy of the
particles. These matters have been put to the
test of experiment in the case of the recoil of
radium B from radium A. and the magnetic and
electric deflections obser\ed show that the recoil-
stream carries with it an electric charge. It is,
however, remarkable that the deflections are such
as to indicate that the charge on the a rays
and recoil-stream is of the same sign — namely,
positive. This fact gives rise to some interesting
considerations as to what happens with the negative
charge when the atom of radium .-\ breaks up, but
the point has not yet been definitely settled.

The magnetic deflection of the recoil-stream can
be observed in different wa\s. of which perhaps the
most interesting is to allow a narrow stream of
radium B particles to pass /;; vacuo through a
magnetic field and fall upon a brass surface. After
some minutes the field is reversed and the brass
subsequently removed and placed in contact with a
photographic plate. The radio-active matter on
the brass, photographs itself, giving two bands
as shown in Figure 2. the distance between the
bands representing twice the deflection suffered
by the stream in passing through the field. .\n
examination of the photograph shows that the
deflection is onl\- half that experienced b\- the a
particles under similar conditions. From the law of
momentum it may be inferred that the charge
carried b\' the recoiling atom is half that on an a
particle, or the atomic charge of electricity, since the
It particle is known to be associated with twice that
charge. The electric deflection of the recoil-stream
has been measured in a somewhat similar manner,
though not yet with the same accuracy. But though
the precise manner of obtaining this information
cannot be entered into, the results suffice to make
certain important deductions regarding the mass of
the atom of radium B — or. in other words, of its
atomic weight. The result of the calculation is to
show that the atomic weight of radium B is in the
neighbourhood of two hundred, a result which
had alreadv been predicted from radio-active theory
as follows : — The atomic weight of radium has
Iieen measured by several in\estigators, and
found to be two hundred and twenty-six. Now
radium gives rise to the emanation with the loss
of one atom of helium, whose atomic weight is four.
Thus the emanation should have an atomic weight of

264

KNOWLEDGE.

July, 1911.

two hundred and t\vent\'-t\\o. and since tliis in turn
produces radium A and radium B successiveh', with
the loss of an a particle in each case, the atomic
weight of radium B should be two hundred and four-
teen. The method of recoil thus gi\(-'s an important
conhrmation of this theoretical deduction.

An account has been given of some new branches
in radio-activity w hich have already been opened to
investigation by the method of recoil. It seems not
unlikel}- that man\' hitherto unsolved problems
may recei\-e explanation when attacked b\- this
recentlv-discovered method.

OX DRAWING ELLll^SES.

liv \V. B. GIBBS. F.K.A.S.

In the numlier of the Joiinuil of the British
A.stniiioiniLiil Association, for .Ma\', 1910. Mr.
Hardcastle has given an interesting accoimt of
a method of forming the boundaries of an elliptic
area bv folding down segments of a paper circle
according to the following rules : —

The paper circle is to be about six inches in
diameter, the centre S is to be marked and also
some other point H, which it is convenient to
choose about two inches from the centre. On the
circumference a number of points are to be marked.
I myself find about thirty are desirable. K (Figure 1).
will serve as an example of one of these points. The
paper is then to be folded so as to bring K to H. and
the crease is to be marked clearly. Then the paper
is to be opened and the next jioint on the circum-
ference is to be brought to H. ami tiiis new crease to
be j^ressed clearly, and so on for the whole number
of points. Then it will be found that a neat smooth
area is left forming an ellipse al)out .S and H, each
crease being a tangent to the curve.

Now I find that this elliptical area can be made
much more distinct, if. when the segments are folded
down, thev be shaded on the outer side with a lead
pencil and then this shading well rubbed with the
finger. Figure 2 shows an example of a shaded
segment. When all the segments have been so
treated and the paper is turned up, there will be seen
on the lower side a clear elliptic area as shown in
Figure 3, the tangent crease lines being also ver\-
plain.

Mr. Hardcastle"s paper is well worth reading in
its entiret}-. He gives a geometrical proof 'that the
area is bounded by an elliptic curve, and also shows
that it is not only interesting geometrically but that
it can be used for dynamical purposes.

It is easily seen that ellipses of any degree of
eccentricity can be drawn in this way. for from
the properties of the ellipse .\S = .\'H = .\'K there-
fore .■\.\ is always equal to SK. or the major axis of
the ellipse is equal to the radius we have chosen for
our paper circle, while the minor axis continuall\-
decreases as H approaches K, vanishing absolutelv
when H coincides with K, the ellipse then becoming
a straight line : but if H approaches S then the minor
axis gradually increases, and ultimatel}', when H
coincides with S, becomes equal to the major axis,

and the ellipse becomes a circle whose radius is equal
to one-half the radius of the original paper circle.
If the radius of the original be 3 inches
Then AS = J -inch
and the minor axis =^ l|-inches
from formulae gi\en in all treatises on conic sections.
In order to draw elliptic orbits b\- this method, I
subjoin the accompan\'ing table giving the eccen-
tricities of the orbits w hich correspond to those values
of SH which lie between two and three inches,
proceedmg b\" thirt\'-seconds of inches. This will
be available for all comets which mo\e in closed
orbits. Taking, for example, Encke's comet, the
eccentricit\' of which is •8476, we see at once we
must take SH between 2g| inches and 2^\^ inches,
because -8476 lies between -84,^75 and -8541, the
nearest numbers given in the table.

^ii;ure 4 I

give a representation of this orbit.

iJisliiiice between

H and S

ill fractions

of an

inch .^nd Ec

:entricily

corresponding tl

iciiiial!..

or t-.

2

2

-666

2:h '.'.'■

2-0J125

67708

2tV, ...

2-0625

6875

2^i ...

2-09375

69791

2i

2-125

708

2^,'^ ...

2-15625

71875

2t',i ...

2-1S75

7291

2;,^v ...

2-21S75

73958

2i ...

2-25

75

2:f^ ...

2-28125

76041

2Ti! ■■•

2-3125

7708

2U ...

2-34375

78125

2ii

2-375

791

m '.'.'.

2-40625

80208

2r\, ...

2-4375

8125

2^ ...

2-46S75

8229

2.^

2-5

833

2}l ...

2-53125

84375

2r'r. ...

2-5625

8541

2^!; ...

2-59375

8646

2s ...

2-625

875

2U ...

2-65625

8854

2H ...

2-6875

8958

2M -

2-71875

90625

2il ...

2-75

9166

2U ...

2-78125

9271

2U ■••

2-8125

9375

2U ...

2-84375

9479

2i

2-875

9583

2M ••■

2-90625 -

96875

21S ...

2-9375

9791

2U ...

2-96875 -

9896

J

3 1

Figure 1.

FiGUKL

FiGLRK

IGURE 4.

265

ox LOADED TELEPHONE CABLES.

By I)K. J. A. FL1:MI\G. F.K.S.
Professor of Electrica! Eiiiiiiccrun; in L'liivjrsity College. London.

W HEN the telephone was first invented and bu.L;;in
to be used, more than thirty years ago, anticipations
were indulged that it would be possible to transmit
the songs of an operatic prima donna or the speeches
of a public orator by submarine cable between
Europe and America. But a very little experience
showed that severe limitations existed to the trans-
mission of telephonic speech through a cable. The
reason for this is the electrostatic capacitv of the
cable. A copper wire surrounded by gutta-percha or
indiarubber, and buried in the sea or soil, forms
a virtual Leaden jar of large capacity The electri-
cal capacity of an ordinary Leyden jar. such as is
used in wireless telegraphy. ma\- be about one-five-
hundredth of a microfarad. The capacit\- of one
mile of submarine cable ma\- be one-third of a
microfarad, or nearly one hundred and se\ent\- times
as much. Hence e\'en twenty or thirt\- miles of
submarine cable has a \-ery considerable capacity :
and the capacity of an Atlantic cable is about eight
hundred microfarads, or about the same as the
capacity of the whole earth considered as a sphere
free in space. The effect of this capacitv is tliat if
we attempt to send an electric current through the
cable it has (so to speak) to be filled up with
electricity- before an\- current begins to flow out
at the distant end. Moreover, if we make sudden
changes in the strength of the current at the sending
end, these changes are not reproduced instantlv at
the other end, or in the same degree. The mathe-
matical theor\- shows that the speed with which
these current changes travel along the cable depends
upon their frequency. Also, the degree to which the
amplitude of these changes decreases, or attenuates.
depends upon their frequency, and upon the constants
or structure of the cable. Current changes of high
frequency attenuate luore rapidly and travel faster
than those of low frequence

Now when an articulate word is spoken to the
diaphragm of a telephone transmitter, the rapid
changes of air pressure which constitute' sound,
compress the diaphragm and produce corresponding
changes of resistance in the carbon granules of the
microphone. These again cause variations of like
nature in the electric current entering the cable.
These current variations are a more or less complete
copy of the air pressure changes. If the cable could
transmit these current changes unaltered to the
telephone receiver at the other end, speech would be
perfectly reproduced. The wave-form, or mode of
current variation, which corresponds to articulate
speech, is very complicated, but it ma\- be resolved
into the sum of a number of vibrations of different
frequency and amplitude. The effect of the electrical
capacity of the cable, as alreadv mentioned, is to

cause an attenuation, or weakening, in the amplitude
of the current vibrations as they are transmitted
along the cable, and this attenuation affects the
higher or shrill notes more than the lower or deep
notes. Also the higher notes travel faster than the
lower ones. It w ill easih' be seen that the result of
this inequalitv is that the wave-form of the current is
distorted by transmission. The different constituent
notes or harmonic vibrations arrive at the far end of
the cable unequalh" degraded, or attenuated, and
shifted in phase relativelv with each other, the high
\ibrations having outrun the lower ones.

If this distortion has not proceeded be}-ond a
certain limit, the ear of the listener is able to guess,
from the sound heard, the meaning of the word, just
as in the case of bad or ordinar\' handwriting we are
able to guess from the general shape of the written
word what it means although the individual letters
are badly formed or distorted. If. however, the
distortion has proceeded bevond a certain point, then
the ear is unable to attach a meaning to the sound
heard, .\part. therefore, from anv imperfection in
the actual telephonic instruments, or in the speech
oi hearnig of the two comruunicants, we have a limit
to the telephonic transmission of speech, imposed
bv the distortional qualities of the cable itself.
•Vccordinglv, it was soon found that the limiting
distance of speech through an ordinary submarine
telegraph cable might be taken as twenty miles or
so. depending on the size of the core. In the case
of land, or overhead, lines, this limiting distance is
verv luuch larger. The cajiacitv of an overhead line
per mile is not a one-hundredth or one two-hundredth
of that of a submarine cable, and therefore
telephonic speech is possible through several
hundred miles of ordinarv overhead wire.

The question of the improvement of telephony b_\-
underground and underwater cables soon began to be
discussed, and foremost amongst those \vhose writings
assisted in laying the true scientific foundation was
Mr. Oliver Heaviside. He showed that the true
antidote to the capacity effects of the cable was to
add to it inductance. This term may be defined, for
the ordinarv reader, as follows: — A coil of wire,
especiallv a coil of manv turns, possesses a property
in virtue of w liich a current started in the wire tends
to run on, anil also the starting of a current takes
time. Inductance, electrically speaking, corresponds
to inertia in the case of ordinary matter. Generally
speaking, we mav say that the presence of inductance
hinders rapid changes of currents in a line, just as
inertia in machinery hinders ver\- rapid changes of
speed in moving parts. For this reason non-mathe-
matical electricians of the old school had arrived at
the idea that inductance in a telephone line should be

266

Jur.v, 1011.

KNOWLEDGE.

267

reduced as much as possible. On tlu' ci;>ntrar\-, Mr.
Heaviside showed that what most telephone lines
required was not less, but more, inductance, to make
them less distortional. In short, inductance is capable
of neutralizini:; ca[)acit\' in cables. The reason for tiiis
is that capacity in cables acts as if it were a sort of
vacuum, into which electricity tries to rush just as air
rushes into a gaseous vacuum. On the other hand.
inductance opposes the m<i\-ement of electricit\' and
hence inductance in series witli capacit\- can be made.

FlGlIRE 1.

Mode of inserting tlie loading coils in tlie two sides of a
teleplione cable.

b\' suitable adjustments, to neutralize each other.
The suggestion was therefore made as far back as
1887 that to effect an improvement in the qualities of
the line it was necessary to add inductance to it. .Ml
problems in engineering are, however, ultimateK'
questions of cost and detail, and until it had been
practically shown that tliis addition of inductance
was both economical and aci\'antageous, telephonic
engineers were liardh- justified in embarking on
expensive constructions. In 1899 and 1900. however.
Professor Pupin, in the United States, published the
results of some remarkable investigations on this
subject. He showed that if coils of \\ire (called
loading coils, see Figure 1) ha\ing high inductance
were inserted in the run of a telephone cable
at equal distances, and so close that nine or
ten of the coils were covered bv or included in
one wave of the current, the result was as if tlie
inductance were smoothly distributed over the
cable and also that provided the inductance were
large enough, a considerable impnnement in the
speech-transmittit^ qualities resulted. The phrase,
wave of current, needs a little explanation. The
characteristic of a wave motion of an\' kind,
whether in air or water, is tliat some change is
periodicalK' made in the medium, which is repeated
successively at contiguous points. If \\e have a long
cable, at one end of which some kintl of periodic or
alternating electromotive force is applied, then the
changes in potential are not rejiroduced instantly at
all points in this cable, but are propagated from point
to point in it with a certain \'elocit\'. The more
rapid these changes the faster they travel, up to
a limiting value which is equal to that of light. .Vt
certain points in the cable, separated by distances
called one wave-length, changes of (lotential of
similar type take place at the same time: tluit is to
say, the [jotential becomes zero or a ma.xiiuum at the
same instant. It is found that the mean \alue of
the frequency involved in ordinar\- speech is nearh-
eight hundred. That is, the mean pitch of the aerial
vibrations has this value.

Corresponding to this frequency in a telephonic
cable the wa\e-length nia\ be ten to twenty miles or
so. Now a telephonic or telegraphic cable has four
specific (jualities. Its conductor has a certain
resistance [ler mile reckoned in ohms, and also a
certain inductance measured in units called a henry.
.\lso it has a certain cajiacits' jier mile, and a certain
leakage per mile.

Mr. Heaviside first shnwtd tliat to make a cable
distortionless in the sense that \\'aves of all frequencies
would travel along it at the same rate, it is necessary
that the product of the resistance and of the capacity
per mile shall be equal to the product of the induc-
tance and leakage [)er mile.

In all ordinary cables the capacit\- is too great to
fulfil this condition, and hence we have to increase
the inductance to approximate to the distortionless
condition.

Pupin showetl that we can add this inductance in
lumps, so to speak, provided we insert these lumps
of inductance at such inter\-als that there are nine
or ten rn\h per wa\'e-length at a frequenc\- of eight
hundreil. A telephone cable so constructed, with
inductance coils inserted in it ever\- mile or so. is
called a locuk'd cable, and loaded cables have of late
years played an important part in im))ro\Mng tele-
phonic communication. .After the publication of
Pupin's researches attempts were made to put them
to practical test in long overhead telephone lines,
both in the United States and in Germany. The
results wen.' ver\' encouraging, and the attention of
t(.>leph(inic engineers was closeh' directed to the

<if,^^^.^^

-dS-A -»

,^'

mi '

Figure 2.

A loading coil for loaded telephone cables as used by the
National Telephone Company.

subject. It is a comparativeh- easy matter to insert
such inductance coils in an overhead line, because
thev can be attached to the telegraph posts, a coil
being inserted in the line circuit every mile or so.

The coils used consist of iron rings built up of
fine iron wire wliich are wound over with man\-

26S

KNOWLEDGE.

JlLV. 1911.

easily
underground

turns of silk-covered copper wire like a trausfurnier
(see Figure 2). These loading coils are enclosed in
iron cases and fixed on the
posts. It is easy to construct
such a coil to have an induct-
ance of about (I'l heiirw and a
resistance of onh- ten to fifteen
ohms.

Loading coils can also be
inserted in the run of
telephone cables,
and such loaded circuits have
been much employed of late
years In' the National Telephone
Companx' (see Figure 3). A
more interesting and recent ap-
plication is in the case of sub-
marine telephone cables. So
inferior is even a length of
twenty miles or so of submarine
cable to an equal or even much
greater length of aerial line in
the transmission of telephonic
speech, that the great obstacle
in conducting telephonic com-
munication with Ireland oi the Continent has al\\a\s
been the interposition of the t\\cnt\- to eight\" miles
of submarine cable necessar\- to cross the English or
Irish Channel. The problem of loading a submarine
cable was. however, one of peculiar difficult^ In an\-
case the la\ing of an unloaded submarine cable

rather reluctant to embark on the enterprise of la\ing a

suhmarine cable

having heavy protuberances in it
every mile or so. Hence as a
first step attempts were made
at continuous loadin
inductance of
increased hv

6- The
a cable can be
windine o\'er it

\ brick pit for coiitaiuint,' the loadin,;^
coils inserted in telephonic cables.

many lavers of fine iron wire
separated, however, from the
copper b\' an insulation. The
effect of this is to increase the
magnetic field surrounding the
conductor when a current flows
throui^h it. .Such a continuousU'
loaded cablf will be thicker
and heavier than an ordinary
unloaded cable, but the risks
in laying it are not thereby
seriously increased. Several
continuoush' - loaded telephone
cables were laid in Denmark.
There are howe\'er. difficulties
in the wa\- of foretelling the
actual performance of such a
class of cable, which do not
exist in the case of cables loaded in the Pupin
manner. The first cable of this last type laid under
water was that put down a few \'ears ago in Lake
Constance. The length of this cable is nine miles
and it consists o( a paper-insulateci lead-co\ered cable,
having loading coils inserted in it at intervals. The

FiGliRB 4. — Section of cable containing loadin;,; coils, complete with sheathing wires

Figure 5.- — .Arrangement of coils in cable.

JUTE SERVlNGlZ UAVERS) JUTE PACKING

S'e'fabout) ■*-

Figure 6. — Method of sheathing over coils.

25 0 -

involvesengineeringdifficultiesof a considerable kind, performance of this cable was such as to encourage
Even when the advantages of inserting the loading further developments, and a year or so back, when the
coils had been well ascertained, cable engineers were authorities of the British Postal Telegraph service

July, 1911.

KNOWLEDGE.

269

began to consider tlie hix'ing of a new telephone cable
across the Enghsh Channel, the question of a
loaded cable was seriously considered. After man\
experiments and measurements, a type of Pupin-
loaded cable was evolved which \vas made and laid
for the Post Office by Messrs. Siemens Brothers, in
1910. This Anglo-French loaded telephone cable was
described to the Institution of Electrical Engineers
recentl}' in a paper by Major O'Meara, C.M.G..
the Engineer-in-Chief_|()f the P>ritish Postal Telegrai)h
Department.

senting the British and Prencli Telegraph Ser\-ices,
between May 15th and May ISth, 1910. Some
special precautions had to be taken in handling the
thickened-u[) portions f)f the cable containing the
loading coils (see Figure 7). The operations were,
however, successfully carried out, and London and
Paris are now connected by a new telephone cable of
superior type containing two complete circuits. The
attenuation constant of the new cable or ratio in which
the current is enfeebled in passing along the cable was
t(jund to be close to the predicted value, and the

FiGURH 7.

Passing over the sheave a loading coil in the Anglo-French telephone (1910) cable laid across the English Ch.inncl.

The cable contains four-stranded copper con-
ductors insulated with gutta percha in the usual waw
and every nautical mile, coils are inserted which con-
sist of silk-covered wire wound over an iron core so
as to form an inductance coil \\liicli is inserted in the
run of the cable (see Figure 5). The gutta percha
insulation and the steel wire armouring are, of course,
continued over the coil, and the result is to produce
an enlargement or protuberance on the cable ever\-
mile.

The cable was laid with great skill by the manu-
facturers at the bottom of the English Channel
between Abbots Cliff, near Doser. and Ca[)e Grisnez,
in France.

The cable was laid h\' the cable ship " Farada\-"
by the experienced operators of Messrs. Siemens
Brothers, and under the inspection of officials repre-

speaking qualities of the cable also fully realised
expectations. }W the employment of extra thick
conductors in the land lines at each end, and
w hen the added distances do not exceed seventeen
hundred miles, Major O'Meara states in his paper
that well maintained conversations bv telephone
could be conducted between London and Astrakhan
on the Caspian Sea. This important achievement
has been watched with great interest by practical
telephone engineers on both sides of the .Atlantic.
The great improvement in the distances over which
it is possible to speak telephonically through cables
when loaded in the Pupin manner is a great testi-
mony to the value of correct scientific theory in
guiding })ractice. The old rule-of-thumb methods
are abolished, tekqihonic engineers are everywhere
engaged in studying the improved methods of

270

KNOWLEDGE.

Jui-v. 1911.

predicting the effect upon tlie speaking qualities
which of certain constructions in telephonic cables
have been based upon the researches of Heaviside
and Pupin, and chieflv reduced to simplicit\' In the
work of Dr. Kennelly, of Harvard University. U.S.A.
The writer of this article delivered last \'ear to
a large class of practical telephone engineers a course

of Post-Graduate Lectures on this subject on behalf
of the Universit\' of London, and these Lectures have
just been published b\- Messrs. Constable & Co.,
in a book entitled "The Propagation of Electric
Currents in Telephone and Telegraph Cables " in
wliich a full discussion of the scientific questions
in\-ol\ed in loaded telephone cables is given.

CORRESPONDENCE.

THE FOURTH DIMI-XSION.
To flic Editors of " Knowledgk."

Sirs, — I much appreciate the article of Mr. .\nnison on the
Fourth Dimension : I regard it as peculiarly fortunate that I
happened to refer to the subject in my letter on The Eternal
Return. Just recently I devoted a fair amount of thought to
the subject of meta-space. approaching it from the geometrical
side. The principal difficulty is, I thinU. that of determining
what analogies are justifiable. For instance, it may be
argued : .^ line can revolve about a point in two-dimensional
space (2 D. space), and a plane can revolve about a line in 3 D.
space ; therefore, a volume can revolve about a plane in 4 D.
space. This seems straightforward, but actually we need to
examine more closely the meaning of the word " revolve."
Suppose we say that " to revohe round " means " to move
continuously at constant normal distance from." Then we
must be careful when talking about a body revolving about a
line. A body moving in a circle should not be said to move
at constant normal distance from a straight line, but from a
curved line — any other coplanar, concentric circle, in fact.

Thus, instead of expecting a Euclidean plane to be a
fulcrum and axis in 4 D. space, we should regard a sphere and
" meta-cylinder " as such.

Now, of course, it is possible to obtain rotation " about a
sphere " in 3 D. space, except that, practically, it is difficult to
devise suitable mechanism. However, my own incomplete
geometrical investigations have shown that, even in 3 D. space,
very curious projected motions arise from a point revolving
" spherically." For instance, suppose we have a ball revolv-
ing about an axis lusing common parlance), and that this axis
is revolving about a line bisecting it at right angles, the two
component angular velocities being the same ; then differently
situated points move in differently shaped loci " in space."
Each " pole " for instance, has the following locus.

Front elevation. — A figure of eight.

Plan. — Two coincident circles, of diameter equal to half
that of sphere.

Side elevation. — Two coincident half-sine-curves.

This may seem irrelevant to the subject of the fourth
dimension, but actually it is not. When one realises the
vast number of 3 D. motions which, either by projection or
section, are similar in 2 D. space, one realises the magnitude
of the task of trying to identify 4 D. figures and motions by
their 3 D. ni.anifestations.

I hope this letter is not unduly long, but I should just like
to say this: As I hinted in the last sentence of my former
letter, we must not lose sight of psychological considerations in
these matters. However. I think that something profitable
might arise from cogitation along the following lines. Instead
of utilising the analogy of 2 D. beings who " sense " 3 D. objects
by their sections in a 2D. world, we should rather deal with
3 D. beings whose " introspectible consciousness" (forgive the
term I) is limited to two dimensions whilst they actually live
and move m three. The analogy must not be pushed too far,
but think of men, who. whilst living and acting (to a limited
extent) in a 3 D. world, sense objects (including one another)
by means of shadows cast on a wall ; also remember how easy
it is for visual space and " loco-motor " space to be dissociated,

as, for instance, when shaving or arranging one's hair, one
thinks of the visual operation as occurring " in the mirror."
Unfortunately, there is a lack of written matter on the fourth
dimension: although I may be allowed to mention Mr. C. H.
Hinton's " Fourth Dimension " (Sonnenschein).

J. JOHN ELLIOTT.

THE SELENIUM PHOTOMETER.
To the Editors of " Knowledge."

Sirs, — I desire to make a few remarks with reference to
your note on the application of the Selenium Photometer to
the measurement of starlight.

First, let me protest against the use of the term Selenium
" cell " to the selenium resistances, which are commonly
employed in photo-electricity. In 1895 I used. at the Daramona
Observatory. Westmeath, a selenium cell, properly so called,
for comparing the lights of stars (see the Proceedings of the
Royal Society Volumes LVIII and LIX). This cell contained
a liquid : and in the cell the light of a star generated an electro-
motive force, the cell being thus quite distinct from the
ordinary selenium resistance, in which increased conductivity
is produced by light. In the Proceedings of the Royal
Society, Volume LXXXL 1908, I described a form of selenium
resistance, called a selenium bridge, which is suitable for star
measurement : and I also pointed out a fallacy involved in the
usual employment of selenium for comparing two lights. I am
afraid that no notice has been taken of this fallacy. In the last-
named paper are given the results of exposing a selenium
bridge to the infra-red, red, yellow, blue, and ultra-blue parts
of the spectrum of one and the same source of light. The
effects of red and blue are enormously different, the red pro-
ducing much greater effect. Hence it will be seen that if we
compare the light of Sirius or Vega with that of Aldebaran or
Betelgeuse. we are not doing justice to the former stars if we
merely allow the total light of the star to fall on the selenium,
and measure it by the electrical effect produced. We should
proceed quite differently. We should split up the various
lights into their spectra, and compare two stars, colour by
colour.

This, of course, requires large telescopes, of which this
country possesses none available ; but in America the thing
could be done properly.

I send you a copy of my 1908 paper, from which you will see
how necessary it is to use spectra when comparing two stars,
and how suitable the selenium bridge is to the purpose. The
bridge is so narrow — as narrow as the thinnest flake of mica —
that the light in any line of a spectrum can be measured.

Another thing of vital importance is to keep aqueous vapour
from the surface of the bridge, or other form of selenium
resistance ; otherwise we get spurious conductivity. I rather
think that this fact has not been attended to in America ; but
I have actually constructed iin electric liygroinetcr depending
on the presence of vapour on the bridge.

I have been hoping to use the selenium bridge here in the
Radcliffe Observatory, for spectrum comparison of stars ; but
the telescope available is only one of small aperture, and other
work has prevented observations.

GEORCH-: M. MINCHIN.

A NOTABLE RECORD.
CAPTURE OE A NEW SPECIES OE MYMAR.

I'.v 1-Ri:i) KNOCK, F.E.S., F.L.S., I'.K.M.S.

Last Ju1\- (1910), it was my pleasure to record in
the pages of " Knowledc;!-:," the interesting fact
that I bred that wonderful insect, Myniar puhlteUiis,
the Battledore Wing ¥\y, on June 14th. when a
male and female emerged from their host egg.
During the past winter, I made collections of various
stems of plants, in and upon \\ hich I found numbers
of eggs, cunningly hidden away, in the pleated leaves
of grasses, or embedded
in the stems in such a
manner that the utmost
care is needed to detect
them and preserve them
from drying up or
becoming mouldy. Great
ingenuity is displayed by
the parent in distributing
them either singh' or in
groups of three or four, so
that the minute operculum
shall be just flush with
the outer covering. Some-
times a single hole is made
about a sixty-fourth of an
inch in diameter, and
through this minute
opening, seven or eight
eggs are laid in such a
manner that the head
end la mere point), starts
from this hole. It is such
eggs that the Myniaridac
search for with unw earying
care, running up and dow n
the stems, keejiing uji an
incessant drumming with
their clubbed antennae —
the under-side near the
tip being covered with
most delicate sensory hairs
— until, by their marvel-
lous sense of touch or
hearing, an egg of the
right species of host — (not
any other), is located. The
tip of the ovipositor is then brought into position
until it is at right angles with the stem, and the
boring through the egg-shell commences, the tiny
mechanic bringing its muscular power to bear upon
the microscopic " broach "' which gradually goes
deeper and deeper and then with a bump goes right

through, sometimes

The germ

of the host's egg-

Myiiiar

Figure 1.
rcgalis, new species (enlarged

up to the bas(
transmitted, sealing the doom
the fluids of which go to the nourishment of the
ovivorous larva. I ha\-e repeatedly obser\-ed the
oviposition of many of the Myniaridac.

The intense heat of June has brought out Myinar
piilchclliis in confinement four days earlier than
in 191(J. Of some S[)ecies we have but single

specimens — and have yet
to obtain more data before
we can state the time of
'■ their appearance. One of

these is Walker's genus
L/;«i7c/.s — of which but five
specimens are known. Mr.
W'aterhouse has taken a
male and female : my
nephew. Mr. [ohn Knock
a female, and I have one,
a male. Limacis is, we
find, one of the earliest
ti) appear — in May. On
I one 3rd. I had a long
da\'s sweeping for it at
Burnham Beeches, but
without success. I only
captured a dozen very
common species, and I
confess to feeling a little
disheartened: for five hours
sweeping and examining
the contents of one's net
with a magnifier is very
trying and fatiguing work.
I had almost decided to
})ack up m\- kit, when I
noticed a likely stretch
of grass, which I swept.
On examining the
sweepings of grass seeds,
and bits of sharp tipped
rushes I was \ery pleased
to see the familiar form
of Mymar running and
skipping about in its own
peculiar manner — running along with its battle-
dore wings arched over its back, then after a
sudden pause — and a jump — somewhere, the search
begins again, until at last a phial is placed over
it, and safely corked. This was my thirteenth
phial, and I "wended my way to the motor-'bus

271

272

KNOWLEDGE.

Jri.v. 1911.

FlGL'RK 2.

Myiiiiir piihlulhin (nialfl iiilart;ed 30 diameters.

FiGUKE i.
Myiiitir rcgdlis (male) new species, enlarged JO diameters.

Jn.v. IQll.

KNOWLEDGE.

273

for Slough, little dreaming that in that phial
No 13, \\"as the most wonderful capture made for
man\- \-ears. On reaching home, I killed my twehe
captures, then <W3'/;(c7r, and was proceeding to brush and
clean it — its battledore wings were in a perfect tangle
requiring care to undo — when I was much troubled
h\ a minute piece of fluff or dust, w hich I could not
remove, so placed the Mynmr under the microscope,
when I was astonished beyond description, for I
looked for an ordinary Myiiiar piilcJicniis with its
abnormalh' short under-wings, instead of which, the
fluff I had tried to remove was an cloiv^atcd posterior
wing, with cilia of six hairs, and I realized that I
had captured a brand new species of Myiiiar \ As
soon as I had mounted it in balsam I telegraphed to
Mr. C. O. W'aterhousc : — '" Cai)tured new species of
Mvnntr. with battledore shaped under-wings."' This
brought us together, and we gloated over the

distinguished visitor. I suggested that we should
christen it Myiinir rci^alls. in honour of His Most
Gracious Majesty, King George V .

On Thursda}-. June 8th, Mr. C. O. Waterhouse
and I had a day at Burnham, and after five hours
sweeping in a bnjiiing sun, I was fortunate
in obtaining another male, so confirming the
genuineness of the species, which not onh- differs
from piilchelliis in its posterior \\ings, but the cilia
around the anterior pair are composed of some sixt\-
long hairs against thirty-five in pukhelliis. In other
respects, the colour and markings are similar.
.\nother long day in search of the unknown female
was not by any means a successful one: in fact, this
Myiiiar is but the one twenty-fifth of an inch in
length, and searching for such a creature on a wide
expanse of wood and common requires a large amount
of patient labour.

SOL.VR l)I.STl'RI5ANCES DURING MAY, iqii.
By FK.WK C. DENNETT.

0\ ten days durins May, namely the 10th to ISth, inclusive, and
the 24th, only facalic disturbances were visible on the disc, dark
spots being seen on the remaining twenty-one. The longitude
of the central meridian at noon on May 1st, was 152 46'.

Nos. 17, 17(7 and 176, continued upon the disc until May
3rd, 5th and 2nd respectively-, and so appear again upon the
accompanying chart.

No. 19. — A pore amid a faculic disturbance within the
eastern limb on the 2nd. and remaining until the 5th. the taenia
being still visible as it neared the western limb on the 14th.

No. 20. — Broke out as a pair of pores 22,000 miles apart, on
the 4th. Next day the following one had increased to a
spotlet, and on the 6th it had developed to an elongated ellipse,
with a major a.\is 48.000 miles in length. It attained its
maximum length of 74,000 miles on the 7th. The dwindling
group reached the western limb on the 9th. Some of the
members on the 6th appeared as slits in the photosphere.

No. 21. — On May 4th. a pore very similar to No. 19,
appeared in a faculic disturbance a little north-east of that
disturbance. Next day two pores were seen with others
ranged behind them like the border of an ellipse, with a length
of 48.000 miles. Much change took place in the appearance
of the group, which was last seen as six pores outlining an
oval area 26,000 miles in greatest diameter, on the 9th.

No. 22. — A pair of pores 19.000 miles apart, with tiny dots
between them, only seen upon the yth.

No. 23. — A spot seen on the 19th close within the eastern
limb. On the 21st it appeared to have a bridge across the
umbra, and also to be situated near the head of a considerable
faculic disturbance. Only two close umbrae were visible
amid taeniae on the 22nd, but when last seen on the 23rd,
there were three pores forming a triangle, the longest side
being 33,000 miles. The area still showed faculic disturbance
as it approached the western limb on May 31st.

No. 24. — Bright faculic ridges were visible on the morning
of the 25th near the eastern limb, a little north, containing a
tiny pore. Other pores showed later and a spot over 7,500
miles in diameter developed during the afternoon. The latter
expanded until 14,000 miles across. The umbra was pene-
trated by a bright projection from the south, from the 28th until
the 30th. The pernunbra brightened at its inner border from
May 30th until last seen on June 5th. It was followed from
the 24th until the 31st, by a group of pores extending back
63,000 miles, and some were seen on the 1st and 3rd, close up
to the large spot. During its visibility it had a forward motion
on the Sun's surface amounting to fully 5° or 37,000 miles.

Bright faculic disturbances were visible within the eastern
limb on the 16th, in the positions shown dotted on the chart,
about longitudes 240° and 255°.

Our chart is constructed from the combined measures,
drawings, and descriptions of Messrs. J. McHarg, A. A. Buss,
E. E. Peacock, and F. C. Dennett, working respectively at
Lisburn, Chorlton-cum- Hardy, Bath and Hackney.

DAY OF MAY, ign.

'?

}■

1,0

?

5

->

V

-, P

3,

30 2

t^

',Ft

?'

?''

rs

^

4

23

?2

^

^0

'P

If

7

'f>

Ir

i»

1?

iO
20
10

1?

2.1 ;

19

2

E

?0

i

17

50
20
10

nl

23

•

"■ '

>

/

oy

20

o

JO

!N

i

«

rCD

N

0 10 20 30 -lO SO 60 70 80 90 100 llO 120 130 l«l 150 IM 170 180 190 200 30 J?0 2X 2«0 250 260 270 280 290 300 310 320 550 MO 350 360

THE FACE OF THE SKY FOR JULY

P.v W. SH.\(KLHTOX. F.K..\.S.. .V.R.C.S.

The Sun. — On the Ist the Sun rises at 3.48 and sets at
tS.lS: on the 31st he rises at 4.22 and sets at 7.50. On the
3rd at 6 a.m. the earth is at its greatest distance froiii the
Sun. the solar parallax then reaching its mininiuin \alue
of 8" -66.

Sun spots may occasionally be observed on the solar disc in
spite of the declining solar activity : at the time of writing no
spots were visible.

The positions of the Sun's axis, equator, and the helio-
graphic longitude of the centre of the disc, are shown in the
following table : —

D

ite.

.\xis inclined
from N. point.

Centre of Df^ic

N. of Sun's

Equator.

Heliogiaphic
Longitude of

Centre of Disc.

June

3° ...

3° 25' W

2° so'

/•^° 55'

lulv

.T ••■

1° N'W

J -J

12' 44'

lo ...

1= 9T.

3° 53'

300° 33'

15 ■

3° 24'K

4° 23'

240" 23'

20 ...

5' 37 '1-^

4" 51'

174° 13'

23 ...

f 46'K

5° 17'

ioS° 5'

30 ...

9" 5 2' I'-

K 41'

41° 56'

.Aug.

4

ll' 52' K

b- 2'

335° 49'

Thk Moon :-

Date.

Phases.

H.

M.

July 3 ...

,. I. ...

., 19 ...

., 25 ...
.\ug. I ...

D
0

(I
•

First (Quarter ...

Full Moon

Last (Quarter ...
New Moon
First Quarter ...

9
0

5

8

1 1

20 a.m.
53 p.m.
31 a.m.
12 p.m.
29 p. 111.

lulv 9 ...

Apofiee

Perigee .

10

42 a.m.
36 a m.

OccuLT.ATlONS. — No occultatious of naked eye stars are
visible in this country during the present month or early
August. „

THE PLANETS.

Mercury : —

Date.

Right Ascension.

Declination.

ll. m.

lulv I ..

6 24

N 24^ 21'

11 ...

7 V>

22° 37'

21

9 14

17" 36'

,, 3t ...

10 14

ir 19'

.Aug 10 ...

10 59

N 5- 8'

Mercury is in superior conjunction with the Sun on the 4th.
After the 20th the planet sets about an hour after the ,Sun in
the W.N.W., thus for all practical purposes he is unobservable,
being in too bright a portion of the sky after Sunset.

■V'ENUS: —

Date.

fulv

Aug

I
1 1
21

31
10

Right .Ascension.

ll.
o
10
10
1 1
II

54
20

39

Declination.

\

14

52'

10

46'

fa"

3"'

N

2"

iS'

S

i"

32'

\'enus continues to be a conspicuous object in the evening
sky looking \V. immediately after Sunset. The planet is
increasing in Ijrilliancy, and reaches her " greatest brilliancy "
on .■\ugiist loth, whilst on July 7th she is at greatest easterly
elongation of 45° 29' from the Sun. At the beginning of July
the planet sets about 10.30 p.m., and at the end of the month,
about 9 p.m.

The planet is so bright that most persons are able to see it
long before it is dark, and this is the best time for observing
with a telescope. The planet may readily be seen, even in
broad daylight if slight optical aid, such as a pair of opera
glasses, be employed and directed to the correct position in
the sky. With the help of nothing but a pair of opera gl.asses
and a celestial globe, I was able to find the planet in the
early afternoon, and after finding it with the glasses it was
fairly easy to see the planet with the naked eye, when shielded
from direct sunlight. During July, the planet is on the meridian
about 3 p.m.; 3.13 on the 1st and 2.48 on the 31st, and as
the brightness is increasing, it should be fairly easy to
discern in the afternoon. As seen in the telescope, the
planet appears like a half moon at the beginning of July,
but the phase rapidly changes, so that at the end of the
month the form is crescent, 0-3 of the disc being illuminated,
the apparent diameter increasing from IT to iT in the same
period. The Moon appears near the planet on the evening of
the 2Sth.

M.\RS : —

Date.

Right .A.scension.

Declination.

h. ni.

Tulv 1 ...

I IS

X b^ r

,, II ...

I 44

8' 29'

,, 21

2 9

10" 47

„ 31 ••■
Aug. 10 ...

2 34

2 5^

12" 53'
\ 14" 44'

Mars rises about ten minutes after midnight on the 1st and
at 10.50 p.m. on the 31st. The planet is situated in Pisces
and appears about half a degree S. of 0 Piscium on the 10th ;
he is rather an inconspicuous object, but as the opposition of
November approaches, he will become more interesting. The
planet is increasing in brightness, the apparent diameter on
July 1st being S"-0 and on August 1st, 9"- 3.

The latitude of the centre of the disc is about — 19°; thus the
southern polar cap is visible, and it is approaching summer in
the southern hemisphere of the planet, the summer solstice
occurring on August 1st.

Jupiter: —

Date. 1 Right .Ascension.

Declination.

July I ...
.. ir ...

,'. 31 -
Aug. 10 ...

ll. m.
14 II
14 12

14 '3
14 16
14 19

.S 11° 58'
12° 3'
12° 13'
12" 29'

S 12° 50'

274

Jl-ly, 1911.

KNOWLEDGE.

275

Jupiter appears as a brilliant star looking S.S.W". at sunset.
The planet sets at 0.42 a.m. on the 1st. and at 10.40 p.m. on
the 31st.

For small telescopes this is the easiest and most interesting
planet to observe, on account of his brightness, numerous
moons, the markings on the disc and polar flattening. A
telescope mai^nifying about fifty times shows the planet of the
same apparent diameter as the moon seen with the naked eve ;
with this magnification and an aperture of two inches, the belts
may be seen, but the moons, when not too near the planet,
may be seen in any good pair of field glasses.

The equatorial diameter of the planet on the 25th is 37",
whilst the polar diameter is 2" -4 smaller: this polar flattening
is readily observed in telescopes powerful enough to see the
belts. If sufficient magnification be used, the Great Red Spot
on the belts may be seen, and the period of rotation deduced.
This is verv short, and accounts for the oblateness, being
only 9'^ 55".

The following table gives the Satellite phenomena : —

4)

c

I P.M.'s.
a. H. M.

1

"y

0

f P.M.'s.

^ H. .M.

0

Q

■1

0
5

1 P.M.-,.

— II. M.

July

I

I.

Sh. I. lo 24

July
6

II.

Sh. I. 10 3

July
24

I.

Tr. I. Q 22

I

I

Tr. E. II 27

S

I.

Tr. I. 11 7

24

III.

Ec. U. 9 :;2

2

1.
II.

Ec. R. 9 44
SH. 1. 11 17

16

111.

I.

Tr. E. 10 45
Oc. D. 10 Q

Aue.

1.

Ec. R. 9 57

2

11.

Tr. E. II 36

17

1.

Tr. E. 0 4-

1.

I.

Sh. E, 9 "4

Sh. I. S 57

"Oc. D." denotes the disappearance of the Satellite behind the disc, and
" Oc. R." its reappearance; "Tr. I." the ingress of a transit across the disc, and
"Tr. E." its egress ; " Sh. I." the ingress of a transit of the shadow across the disc,
and ".Sh. E." its egress; "Ec. D." denotes disappearance of Satellite by Eclipse,
and *' Ec. R." its reappearance.

The configurations of the Satellites as seen in an in\erting
telescope, and observing at 9.30 p.m.. are as follows : —

Day.

West.

East.

Day.

We-l.

Ei.si.

I

43 0

2

17

42 0

3

2

43 0

• I

18

4 0

I 3 92

3

421 C

3

19

41 0

23

4

4 0

213

20

42 ■

3'

5

41 0

23

21

4321 .

6

243 0

I

22

34 0

12

7

321 C

4

23

314 0

2

S

i

124

24

2 0

■4 •;

9

3 -

^4 •!

25

2 C

34 •■

lO

21 ^

34

26

I c

234

II

0

!34 •-'

27

2 C

314

12

I 0

234

28

>■ 0

4

ij

2 0

14

29

3 0

'i 4

14

321 0

4

30

31 0

24

15

34 0

12

3'

2 0

? 4

16

43' 0

2

The circle (C represents Jupiter : 0 signifies that the
Satellite is on the disc ; • signifies that the Satellite is behind
the disc or in the shadow. The nuuibers are the numbers of
the Satellites.

S.-\TURN :

Date.

Right Ascension.

Declination.

lulv I ...

., i6
.Aug. I .

ll. 111.
; o
3 6
3 lo

X 14'-' 47'

15'^ 6'

X 15^^ 21'

Saturn rises E.N.E. on Jtily 1st at 1 a.m., and on .A.ugust
1st at 11.5 p.m. The planet is situated in Aries, and will be
more favourably placed for observation during the next few
months than he has been for many years past.

The ring, as seen in the telescope, appears well open, the
apparent diameter of the outer major axis being 40". and of
the outer minor axis 15"; the southern surface of the ring is
visible, and inclined to our line of vision at an angle of 22°.

Uranus : —

Dan-.

kiglit

Ascension.

Declination.

lulv I ...
Aug. I ...

h.

20

iq

111. s.

1 28

jG 21

S 21^' 5' ii

S 21° 20' 15"

Uranus rises in the S.E. at 9.20 p.m. on July 1st and at
7.12 p.m. on August 1st. The planet is in opposition to the
Sun on the 21st. hence about this date he appears due South
at midnight ; he is describing a retrograde or westerly path,
about 2^ S.E. of <r Capricorni and can just be discerned with
the naked eye on a very clear night. The planet's remarkable
spectrum of broad dark bands is well worth the attention of
observers, even though they possess only small instruments.

Neptune: —

Date.

Right Ascension.

Declination.

[ulv I ...
Aug. I ...

ll. 111. s.

7 20 3?
7 34 23

X 21'^ 16' 20"
X 21" 6' 2"

Xeptune is Hot observable this month, being in conjimction
with the Sun on the 14th.

Meteor Shower. — The most notable shower in July is
that of the S Acjuarids. which occurs on the 28th. The radiant
is situated in R.A. ZZ'^ 36"', Dec. S. 11". and the meteors are
slow, with long tails.

The Perseid shower also commences about the 10th. the
radiant being initially near o Cassiopeiae.

Mira lo Cetil was due at maximum on June 30th, but as
the exact date is somewhat uncertain, observations of magni-
tude should be made for some time after this date. The mean
period is about 331 days. The star is also remarkable for
its spectrum, which may be well observed in a three-inch
telescope, using a Maclean or Zollner spectroscopic eyepiece ;
the spectrum consists of broad dark bands, in which bright
lines, due to hydrogen, occur.

TELESCOPIC Objects (Double Stars, &c.l : — 5 Serpentis.
XV." 13"", X. 2° 13'. mags. 5-1, 10; separation 10".

(i Serpentis. W." 41"'. N. 15° 44', mags. 3-8, 10; separation,
31".

f> Serpentis. XVIII." 51'", X. 4= 4'. mags. 4-0. 4-2; separa-
tion. 21"- 6. Both are yellow, the primary being paler than
the smaller star.

t Cephei XXII.'' 1'", X. 64' S'. mags. 4-7. 7 ; separation,
6".

0 Cephei XXII.'' 26". X. 57° 57'. mags. 4-2. 7; separation.
40". .A pretty pair for small telescopes, stars respecti%ely
yellow and blue. It is also a typical short period variable
star, not of the Algol type, the period being 5'' 9''. with a sharp
rise from minimum to maximum in 1'' 9|''.

Cluster in Libra. M 5. A compact cluster situated about
one-third of a degree North of the double star 5 Serpentis ; it
appears like a large nebulous .star when viewed with a pair of
opera glasses.

Cluster in Serpens, N.G.C. 6633 ; about one-third of the
way from 0 Serpentis to a Ophiuchi. The cluster is visible to
the naked eve.

NOTES.

ASTRONOMY.

Hy A. C. I). Ckommelin, D.Sc, H.A.

THE SUN'S DISTANCP: DETEKMINia) 1 K( )M
EROS. — Last year Mr. A. R. Hinks published the result of a
very e.xhaustive discussion of the Sun's distance from the
observations of Eros at the time of its near approach in 1000-
1901. His final value for the Sun's parallax is S"-806.
Taking the Earth's equatorial diameter as 7925-45 miles, the
Sun's distance is 92.831,000 miles, with a probable error of
some jO.OOO miles. This result is very close to that previously
deduced by Harkness from a Least-Square adjustment of all
available material, and also to Gill's result from the minor
planets Iris, Victoria and Sappho. It is expected that Eros
will in the course of years afford a much more accurate
determination than any yet made, by the very large
perturbations which the earth causes in its motion. Careful
observation of these will give the ratio of the Earth's mass to
that of the Sun. from which the distance of the latter readilv
follows. These perturbations can be expressed as a series of
regular waves, or Sine-curves, of various periods. The
largest wave has a period of 40-6 years, the amplitude of the
Cosine part of it being — 703", and the argument seven times
Eros' Mean Longitude — four times that of Earth. There is
another large term with amplitude 259" and multipliers of the
longitudes 37 and 21; period 82-6 years. A more accurate
knowledge of the period of Eros is required before this last
term and others of longer period can be accurately calculated.
Forty-six revolutions are so nearly etiual to eighty-one years
that it is still uncertain in which direction they differ. The
shift in the planet's place due to these terms is increased by
the eccentricity of the orbit, and by the fact that the planet
is at times so near the earth that the heliocentric shift is
increased sixfold. A total range of some 3° may thus arise,
and as the range due to parallax is only 2' at most, it will be
seen how much the method of perturbations will eventually
surpass the other. It will probably not attain its full accuracy
till two or three times the forty-year period ha\e elapsed.
But it is likely that before the Transit of Venus in 2004 the
Sun's distance will be so well known that observations of
the Transit will be useless for this purpose, and will simply
be employed for correcting the elements of Venus' orbit. I
have taken the above figures from a paper by Heinrich
Samter in Astr. Nach., No. 4498.

NEW DETICKMI NATION OF THE MOON'S
DISTANCE.— During the last six years the small- bright
crater Mosting A has been regularly olsserved on the meridian
both at Greenwich and the Cape. It is much easier to bisect
the crater with a micrometer wire than to place it tangential
to the Moon's limb, which is often serrated by mountains.
About a hundred nights are available on which the crater was
observed at both stations, and comparison of these has given
a new determination of the Moon's distance. The chief
source of uncertainty in the result is the fact that the shape
of the earth is not yet known with great precision. The
distance was accordingly computed on two assumptions of
the shape, \'u., compression L293i and 1/300; these about
cover the present uncertainty. On the 'Tfirst assumption
Hansen's parallax (which is 57' 2"-23) needs a correction of
plus 0"-50, and on the second of plus 0"-12. On the former
assumption the Moon's distance comes out 238,817 miles.
Another way of finding the distance is based on the observed
period and the force of gravity at the Earth's surface. This
method also gives results that vary, though to a less extent.

with the Earth's figure. The deduced corrections to Hansen's
parallax are 0"-45 and 0"-36 on the above assumptions.
Hence to make the two methods agree we must take the
compression as 1 , 294A. This applies to the mean meridian
of Greenwich and the Cape, for it is cjuite possible that
it is sensibly different for different meridians. Sir David
Gill has for many years been endeavouring to have
South Africa geodetically connected with Europe, and
only a few links are now needed to complete
this great work, which would give a measured meridian
extending from the North Cape to South Africa, and would
give the compression of this meridian very accurately. It
seems to nie that it would be advisable for equatorial observa-
tories to measure the moon's distance by the diurnal method
(comparing observations made east and west of the meridian
at the same station). The equatorial parallax of the moon
would thus be given, free from uncertainty arising from the
figure of the earth, and it would in addition be possible to test
whether the equator has any ellipticity by comparing the
results obtained at different equatorial stations. The measures
might be made photographically, for Professor Pickering and
Mr. H. N. Russell have lately shown that good photographs
of the moon for position can be obtained by giving the
surrounding stars a time exposure, the moon being screened
by a disc except for a fraction of a second, the time of which
may be automatically recorded. This plan is analogous to
that used for many >-ears at Greenwich for photographing
Neptune and its satellite, and double stars that differ much in
brightness.

BOTANY.

P>y Professor F. Cavers, D.Sc. F.L.S.

THi; llloLOGV OF LICHENS.— A vast amount of con-
troversy has centred around the relationship between the two
components of the thallus, or plant body, of the Lichens. .A
recent short paper by Tobler {Ber. liciitscli. hot. Gt's., 1911)
serves as a reminder that the question is by no means settled,
and the following notes may be of interest to the student of
plant life who knows something of the general characters of
these curious organisms.

The Lichens form a quite exceptional group of plants, with
various peculiar features. A Lichen is a couipoimd plant,
consisting of a Fungus individual and numerous .^Iga
individuals. The Fungus, composed of branching and inter-
lacing threads, has grown around the Algae, enclosing them in
a sort of nest, in a manner which has often been compared to
the enmeshing of a fly by a spider. The result is that the
Lichen can grow in places which would be unsuitable for the
independent existence of either the Fungus or the .Algae of
which it is composed. Algae grow in water or in moist
places, and very few can live without a regular and abundant
supply of moisture, while (apart from the leathery bracket-like
forms) Fungi are very sensitive to cold and drought. Vet
the Lichens thrive in the bleakest positions and in the most
severe climates, as on bare mountain rocks where they may
get no water for weeks on end, or may be soaked with rain
and mist for equally long periods, and where they are exposed
to great extremes of heat and cold.

In a typical Lichen the Fungus provides the organs of
fixation ; protects the Alga cells from drought and other
injurious infiuences; absorbs water with dissolved salts,
and air witli carbon dioxide; and it alone produces the
spore fruits. The Alga, on the other hand, manufactures
organic food, with the help of light, from carbon dioxide .and

276

JlLV. 1911.

KNOWLEDGE.

277

water and salts, and it shares with the Fungus in producing
the asexual brood bodies or soredia.

Both the Fungus and the Algae which make up a
Lichen can. under suitable conditions, be induced to grow
independently, though in the Lichen body itself they are
mutually dependent upon each other. The isolated Alga
cells grow and multiply when suppUed with water, a few
simple salts, and air containing carbon dioxide. The Lichen
spores will germinate in a culture solution containing organic
substances (sugar, and so on) and produce a small thallus
which contains, of course, no Alga cells.

The reproduction of a Lichen is somewhat complicated, for
we have to consider the processes of multiplication carried on
by (1) the Alga cells, (2) the Fungus, (3) the Lichen as a
whole. ( 1 1 The .^Iga cells increase in number by growing
and dividing as if they were living independently, but do not
bring about the reproduction of the Lichen as a whole. (2) In
spore formation the Fungus alone is concerned, the spores
being formed in special sac-like threads (ascil which develop
from the Fungus web. The spores on being carried by the
wind to a suitable place, germinate and, if the right .^Iga is at
hand, the Fungus threads surround them and a Lichen thallus
is woven. By sowing Lichen spores on plates on which
minute Algae are growing, we can readily observe the
production of a Lichen. In Nature, the .-Vlgae usually present
in Lichens are widespread, so that the formation of a young
Lichen thallus depends largely on the existence of suitable
general conditions for growth. (3i Many Lichens are largely
propagated by means of small brood-bodies (sorediai. budded
off by the thallus. Each soredium consists of a few Alga
cells, or only one. surrounded by a web of Fungus threads.
Sometimes these soredia are produced in definite clumps, but
more often they form a powdery layer sprinkled o\er the
thallus.

It must be remembered that the view of the symbiosis, or
mutually beneficial partnership, relation between Fungus and
Alga applies strictly only to the Lichens that grow on bare
rocks and stones. In fact, even in these cases the Fungus pro-
ceeding from the germinating Lichen spore must be supplied
with some organic substances derived from decaying plant or
animal remains on the rock or stone. The Lichens that grow
on ordinary soil, and on trunks of trees, resemble ordinary
Fungi in being saprophytic — that is, they live at the expense
of decaying organic matter, so far as the Fungus constituent
is concerned. Moreover. man\- Lichens that grow on leaves
in the Tropics, as well as some that grow on trunks, are more
or less distinctly parasitic, drawing part, at least, of their
nourishment from the living cells with which they are in
contact by their underside or by their fixing and absorbing
organs (rhizines).

.\s a matter of fact, \arious writers ha\e maintained that
the relation between the I'ungus and the Alga in a Lichen is
simply one of parasitism on the part of the Fungus. In some
cases, the Fungus threads have been seen to penetrate the Alga
cells instead of merely spinning an enclosing web around them,
and the presence of dead Alga cells in various Lichens has
suggested the view that the Fungus kills the Alga by means
of ferments. Possibly the Fungus makes use of the .\lga for
some time after its spores have germinated, and then proceeds
to live in the same way as an ordinary saprophytic Fungus
when on a substratum rich in organic matter. This view is
supported by the fact that Fungi which normally form part of
a Lichen have been found growing independently, and there
seems little doubt that in most Lichens the Fungus is capable
of absorbing organic food from the substratum and is not
dependent upon that which is manufactured by the Algae.

From the structure of the Lichen thallus it is clear that the
Alga cells are placed in somewhat unfa\ourable conditions for
the making of food by carbon assimilation. They are not at
all well situated with reference to light and air, being covered b>'
the thick dense cortical tissue which often contains various
pigments and is thus darkened, while the compactness of the
overlying tissue makes difficult the access of atmospheric air
to the green cells. The latter difficulty is in many cases
obviated by the presence of special canals and slit-like rifts in

the cortex. In some of the Parinclia species, which have been
carefully examined by Rosendahl ^Nova Acta Leop.-Carol.
Acad., 1907) the cortex, elsewhere thick and consisting of dense
tissue, shows at places a loose texture corresponding to the
lenticels in the cork of tree stems, while in those species which
have a thin and delicate cortex these lenticels do not occur.
That lack of light and air tend to restrict the grow^th of the
.Algae is further shown by the fact that the usually continuous
.\lga layer is often interrupted below the fruits of the Lichen,
and also below the places occupied by parasitic Fungi which
are sometimes found growing on the surface of the Lichen
thallus.

An interesting line of research in the physiology of Lichens
is opened up by the striking results obtained by Treboux and
other workers, with reference to the nutrition of the simpler
Green Algae. It has been shown that many of these
unicellular Algae can utilize organic acids (acetic, lactic,
oxalic, and so on), as a source of carbon, light being
unnecessary for the process, and that among the simple forms
tPleurococciis and others), which can obtain food in this way,
the common Algae found in Lichens are included. These
Algae, w^hen supplied with organic acid solutions, can grow
and develop in complete darkness. Lindau iLichcnologischc
Uiitcraiichitngeii. 1S95), noticed in a Lichen iPyrcitiila
nitida^ that not only the Fungus threads but also those of the
Alga, penetrated the b.irk of the tree on w^hich the Lichen was
growing, although the Alga (in this case a filamentous one
belonging to the genus Trciitcpohlia^ is only loosely bound
up with the Fungus threads.

Tobler suggests that the Alga in a Lichen may utilise as
its source of carbon organic acids which are formed as bye-
products in the nutrition of the Fungus. It has long been
known that oxalate of Ume frequently occurs in crystalline
masses and incrustations on the threads of the Fungus in
Lichens, as well as on the threads of ordinary Fungi. In
Lichens, the oxalate is never found associated with the .-Vlga
cells. Oxalate is also produced abundantly in cultures of
isolated Lichen Fungi, even in cases where the Lichen itself
is free from it. From his culture experiments, using the
common yellow Lichen, Parinclia parictina. Tobler finds
that (1) calcium oxalate is freely produced by the Lichen
Fungus grow^n on gelatine ; (2) on the other hand, developing
Lichen plants on the same substratum, arising from the
.addition of the Algae to the Fungus, produce no o.xalate ; (3)
fully de\eloped plants of this Lichen, growling on bark, contain
no oxalate ; (41 in fluid cultures, containing no source of
carbon excepting the carbon dioxide of the atmosphere, the
Alga cells remain green and grow in the normal manner ;
(5) if the Lichen Fungus is also present in the culture the
.\lgae become colourless, but continue to grow luxuriantly.

Many other facts support the view that the .\lga in a Lichen
may use the oxalic acid, and possibly other organic acids,
produced by the Fungus. For instance, Rosendahl showed
that in the brown Paruielias, thinness of the cortex and
presence of oxalate of lime go hand in hand — evidently in
such cases the .\lga receives sufficient light to enable it to
make food by photosynthesis, hence it does not use up the
oxalate.

EVOLUTION' OF THE FLOWER.— Wernham. in his
second article on Floral Evolution, in the Xexc Pliytologist,
(see ■' Knowledge " for June, 19111, deals with the Lower
Dicotyledons (Archichlamydeae) in some detail, with
special reference to their phylogenetic relations to the Higher
Dicotyledons (Sympetalae or Gamopetalae). It is remark-
able that whereas the flowers of barely twenty per cent, of
the former have the stamens equal to or less than the corolla
segments, this character is found in nearly ninety-five per cent,
of the species of Sympetalae. Again, only about eighteen per
cent, of the .\rchichlamydeae have a pistil composed of two
syncarpous carpels, while in the Sympetalae fully seventy-five
per cent, of the species have a bicarpellary pistil. The conclusion
to be drawn is that the progressive tendency to economy of
production, observable at work in the Archichlamydeae. has
reached a high degree of realization in the Sympetalae, in

KNOWLEDGE.

July, 1911.

which also we find higher adaptation to insect visits. In the
Sympetalae, ^ygoniorphy occurs in nearly lifty per cent, of
the species, as against barely fifteen per cent, in the case of
.■\rchichlainydeae. .■\ggregation into dense inflorescences is
the chief feature of the Compositae. an order which comprises
over twenty-seven per cent, of the total number of Sympetalae,
and. indeed, over ten per cent, of the sum total of flowering
plant species.

The author then gives a summary of the various cohorts and
orders of Archichlamydeao. tracing the evolutionarv tendencies
through this series. Taking first the essential organs — the
androecium and the pistil — the general tendency to econonw
in production of parts is emphasized, and the question is raised,
■■ To what extent has the working of the principle of economy
been accompanied by the compensatory tendency of progressive
adaptation to insect visits ? " In this connection attention is
called to the absence in Archichlamydeae of a strong tendency
io floral angregation. such as we find realized and e.xpressed
in the Compositae among the Sympetalae. Dense
inflorescences occur in isolated cases throughout the Low^er
Dicotyledons, but aggregation does not characterize any
relatively large group except one, the Umbelliflorae. in whicla
the inflorescence unit is typically a close umbel. The general
tendency to zygoiuorphy goes hand in hand with progressive
aggregation, the outer florets tending to bilateral synnnetry
and especially to increased development of the corolla on the
outer side. In the Lower Dicotyledons, however, the
zygomorphy of relatively large and solitary flowers occurs
only in isolated cases here and there, but does not form a
critical character of any great group comparable with the
Personales and Lamiales in the Sympetalae. .Again, fusion
plays a very inconspicuous part among the Lower
Dicotyledons : a corolla tube is, of course, absent, though
some specialised " apetalous " groups (e.g., Proteales) have
flowers with a typically gamophyllous perianth. In the
Geraniales and the Papilionaceae, however, a tube is formed
by the cohesion of the filaments of the stamens. But a far
more extensive tube-forming tendency in the .-Xrchichlamydeae
is that produced by means of the progressive hollowing of the
flower receptacle.

In the higher families of .Archichlamydeae, from the
Buttercup cohort (RanalesI upwards, we find various stages
of pcrigyny. leading to cpigyny. The inferior position of the
ovary may. however, have been produced in descent in other
ways than by a gradualU- increasing degree of perig\ny,
though this method alone has left any continuous trace among
existing plants. Whatever the evolutionary methods of its
production may have been, the inferior position of the ovary
conduces to economy in production, since in this way
receptacular tissue can be pressed into the service of ovule
protection and fruit formation. At any rate, it is certain that
these floral types, such as the Compositae. which are
admittedly in the \an of evolutionary .advance, invariably
have an inferior ovary, w^hile no epigynons flower can be
called unquestionably primitive.

In attempting to find some phxletic connection between the
.Archichlamydeae and the Sympetalae. one can hardly suppose
that the cohesion of the petals, which is the sole .essential
difterence between the two groups, followed upon one line of
evolution, nor that sympetaly originated at one point only of
any particular line. That is. there is a prima facie presump-
tion that the Sympetalae are polyphyletic in origin, yet even if
the series is composite it is also synthetic, in so far that its
component members may be connected on the lines of certain
well-marked progressive tendencies to biological advance.
These tendencies do not difier fundamentally in any way from
the tendencies seen at work in the .Archichlamydeae. but they
do differ in degree, as might be expected from the relatively
high biological organisation of the group. The tendency to
reduction of parts has already reached an advanced stage of
realisation, and it plays a secondary role in the Sympetalae. in
which the prominent factor is that of progressive .adaptation
to insect visits.

In the Sympetalae. tlie (endency to economy in production
is expressed by («! reduction of stamens to a number less
than that of the corolla segments, following upon zygomorphy :

<h) progressive reduction of the calyx to a pappus or to zero;
k") reduction of the carpels to two. the loculi to one. and the
ovules to one.

The tendency in Sympetalae to progressive adaptation to
insect visits is shown in (al the general introduction to
zygomorphy in Tubiflorae on the one hand and in .Aggregatae
and Campanulatae on the other, representing the two types of
zygomorphy shown in .Archichlamydeae; (b) the pollen
presentation mechanism, a general feature of the Campanulatae
and especially of the Compositae order.

CHEMISTRY.

By C. .AiNSWORTH Mitchell. B..A. lOxon.), F.I.C.

MF.ASLKEMEXT OF POLLUTION OF THE AT.MOS-
PHFKF. — Hitherto, the only chemical means of determining
the degree of pollution of the atmosphere has been to estimate
the proportion of carbon dioxide, and draw a deduction from
the amount by which it exceeded the normal quantity. This
method could only be regarded as giving approximate values,
since carbon dioxide is one of the products of combustion as
well as of respiration, and its estimation aftbrded an indication
of the degree of ventilation rather than that of the vitiation of
the air, which is due to the condensation of animal products
of excretion.

.An ingenious method of measuring these condensed products
has been devised by MM, Henriet and Bouyssy [Coiuptcs
Rendiis. 1911, CLIL, IISOI. It is based upon the fact that
pure air always possesses oxidising properties, whereas
excretory products are all reducing substances, and thus an
estimation of the reducing property of a measured volume of
the air is strictly proportional to the degree of pollution. The
foreign bodies of organic origin to which pollution is due,
are condensable simultaneously with the moisture in the
atmosphere, and the method, therefore, consists of three
steps: — (1) Condensation of a gi\en volume of water from the
atmosphere by means of a freezing mixture; (21 Calculation
of the quantitN' of air corresponding to the amount of water
condensed: and 13) Estimation of the amount of potassium
permanganate solution reduced by the organic impurities in an
aliiiuot part of the condensed moisture. The results are
calculated into the corresponding quantity of oxygen, and
expressed in milligrannnes per one hundred cubic metres of air.

By this method the relatively pure air in the Montsouris
Park, in Paris, gave a value of one, whereas the air in the
vicinity of the H6tel-de-Ville had a value of ten. .A room in
which several rabbits and monkeys had been kept gave the
value thirteen, and the same figure was obtained with the air
in a printing works. The figure fourteen was given by the air
in a badly-ventilated office, and seventeen by that in a dark
passage, while a dressmakers' work-room in which twenty
people had been working all day with the windows closed gave
the extremely high value of twenty-one. It seems probable
that this method will prove a very valuable aid to the hygienic
investigation of the air in closed places, such as submarine
vessels.

BACTERIOLOGICAL STUDY OF HONEY.— An
interesting investigation of the species of bacteria present
within the cells of the honeycomb derived from different
parts of France, has been published by MM. Sartory and E.
Moreau \.\niiales des Falsifications. 191 1. I\', 259). .Among
the bacteria of common occurrence in the air. w-hich had been
introduced by the bees into the cells, were the following
species: — B. siibfilis. B. nicgateriiini, Sarciiia Intea, B.
aeropliiliis. and Sfaphylococcits pyogenes. There were
also several mould-fungi and yeasts, including Peniciiliuni
glaiicuni, Saccharoinyccs ccrevisiae. Mucor raceinosiis and
.Aspergillics gracilis. .Among the bacteria was a golden
yellow species, which secreted a bright yellow pigment soluble
in absolute alcohol. It had a strong liquefying action upon
gelatin, and differed in its biochemical characteristics from
several very similar yellow bacteria. It appeared to be
intermediate in its properties between the Bacillus liitcKs of

jL'i,v, ion.

KNOWLEDGE.

279

A NEW RADIUM PREP ARA TION.— An extremely
active preparation of radium is now produced at the Neulen-
bacii radimn works, by means of a combined acid and alkaline
fusion process, wliich extracts the radium directly from the
minerals in the form of a crude sulphate. According to
A. Fischer Xhcin. ZcntralhJatt, 1911, I., 1190) it is possible
by this means to treat ten thousand kilogrammes of pitchblende
residues and obtain crude radium chloride from them within
six weeks, while ores containing ten per cent, and less of
uranium oxide, which hitherto could not be economically
worked up, may now be used in the preparation of radium
compounds. Preparations of radium showing an acti\ity of
upwards of three hundred thousand units (Machel per 10 c.c.
are now produced at these works. Experiments h.'ue shown
that radium enters the human system chiefly by inhalation
and not through the pores of the skin.

ARSENIC IN SEA-WEEDS.— It was shown by Gautier
some years ago that arsenic was a normal constituent of
certain marine algae, and this has recently been confirmed bv
MM. Tassilly and Leroide [Bull. Soc. Chiin., 1911, IX., 63).
There are numerous secret medicinal preparations made from
algae, including some of the anti-fat remedies, and experiments
have shown that the whole of the arsenic will pass into these
products. In addition to this, a small proportion of arsenic
may be derived from impurities in the other ingredients of
these remedies. The proportion of ar.senic in marine algae
and mosses of the same species varies but slightly, though
there are considerable differences in the case of different
species. The following results, expressed in milligrammes per
hundred grammes of the algae, containing twenty to thirty
per cent, of water, are typical of those obtained ; — Choiidrus
crispiis, 0-070; Fiicus vcsiciilusus, 0-010; Corsican moss,
0-025; Lainiiiaria digitaia, 0-05Q; L. saccharina, 0-010 ;
and L.ricxicaiiHs. 0-010.

GEOLOGY.

By Russell F. Gwinnell, B.Sc, A.R.C.S., F.G.S.

A GIGANTIC GEMSTONE.— A remarl<able crystal of the
precious beryl (a mineral which is known as emerald or as
aquamarine, according to the particular shade of colour which
it exhibits) was recently described in a paper read before the
New York Academy of Sciences. This crystal, the largest
beryl ever found, was disco\ered by a Turkish miner in a
pegmatite vein in the State of Minas Geraes, Brazil.

The crystalline form was the usual hexagonal prism
terminated at both ends by the basal plane. .'\lthough
measuring 48-5 centimetres in length, the crystal was so
transparent that it could be seen through from end to end
when viewed through the basal termination. Its width was
from forty to forty-two centimetres, and its weight 110-5
kilograms, or well over two hundredweight. It is estimated
that the crystal would furnish at least two hundred thousand
carats of aquamarine gems of various sizes, when cut.
Twenty-five thousand dollars is said to have been paid to
the finder for the stone.

For comparison with this gemstone, it may be interesting to
recall the figures for some celebrated diamonds. The
Koh-i-Nur, when brought from India, weighed one hundred
and eighty-six carats (about one and a quarter ounces) and now,
after recutting, weighs one hundred and six carats. Brazil pro-
duced the Star of the South, weighing two hundred and fifty-
four carats when cut, but while holding the record for beryls,
Brazil is easily surpassed by South Africa in diamonds.
Thus the Stewart weighed two hundred and eighty-eight carats
and the Porter Rhodes no less than four hundred and fifty
seven carats (about three ounces) when found. But all previous
records were beaten when, in the newly-discovered Premier
mine in the Transvaal, the Ciillinan diamond was found in
the yellow ground, in 1905. More than three times the size of
any known diamond, this stone weighed three thousand and
twenty-five and three-quarter carats, or one-and-a-third pounds,
and was clear and water-white throughout. The largest of its

surfaces appeared to be a cleavage plane, so that it might be
only a fragment of a nuich larger stone. Purchased by the
Transvaal Government in 1907, the CiilUnan was presented
to King Edward VII. It was cut, in Amsterdam, into nine
large stones and a number of smaller brilliants.

THE GREAT PROVINCES OR BRANCHES OF
IGNEOUS ROCKS.— The old system of grouping the whole
assemblage of igneous rocks along one line of variation, from
acid through intermediate to basic, is gradually giving
wav to a more complex, but apparently more natural, system.
In "The Natural History of Igneous Rocks" Harker states
that we shall make a decidedly closer approach to the facts if
we assume, not one, but two main lines of variations. Each
line may be conceived as spanning the interval between the
basic and acid extremes, the two diverging most widely near
the middle of their course. These great provinces or branches
are spoken of as the " Atlantic " or " alkalic " group and the
" Pacific " or " sub-alkalic " group. These two great branches
of igneous rocks have a well-marked areal distribution, and
define two petrographical regions of the first order of
magnitude, which stand in relation to the grandest tectonic
features of the globe.

Although in the main the .Atlantic tvpe of rocks occur
towards the Atlantic sea-boards both in the American
continent and the Eurasian continent, and the Pacific type
towards the Pacific sea-board, yet many exceptions occur.
Moreover, in a country like Patagonia, where the Pacific and
.■\tlantic Oceans come near together the types are curiously
interwoven, as in the case cited below.

In a recent paper, also dealt with below, there is established
a third "natural family" of igneous rocks, the spilitic suite,
which is clearly distinguished from the Atlantic and Pacific
suites.

In the American Journal of Science for May, Professor
L.V. Pirsson refers to" Geologisch-petrographische Studien in
der Patagonischen Cordillera ; von P. D. (Juensel."

TraveUing from Cape Horn northwards along the chains of
the southern .\ndes the author throws much light on the
geology of this little-known region.

A feature of interest to petrographers is the occurrence, at a
number of places, of alkalic rocks. These consist of intrusive
masses of essexite in stocks, exposed domes, and so on. These
rocks are composed of purple pleochroic titaniferous augite,
brown barkevikite, labradorite and analcite, the latter regarded
as secondary, perhaps after nepheline. They are accompanied
by a series of dykes of bostonite and camptonite with essexite
porphyry, and the author parallels the occurrences with those
of Southern Norway, made classic by the researches of
Briigger. In other places aegirine-granite-porphyry is found
with the essexite. The occurrence of these alkalic types in
the sub-alkalic province of the Andes is interesting.

In the Geological Magazine for May and for June, 1911,
Messrs. Dewey and Elett deal with " British Pillow-Lavas
and the Rocks associated with them." These pillow-lavas are
a group of basic igneous rocks, occurring only as submarine
flows and very frequently exhibiting " pillow-structure." The
term " spilite " is used to designate these lavas, which are
found among Carboniferous, Devonian and Ordovician rocks
in Devon and Cornwall. A great variety of types are comprised
in the family, and they range from ultra-basic picrite to such
acid extremes as quartz-keratophyre, soda-felsite and albite
granite. The essential characteristics of the family are the
abundance of soda-felspar and the remarkable frequency with
which they have been albitised. The albitisation is not due
to weathering or to shearing, but it may be grouped as a post-
volcanic or juvenile change, produced soon after solidification
of the rock. Like the .\tlantic and Pacific igneous suites the
spilite group has an intimate connexion with certain types of
geological conditions. They are essentially rocks of districts
that have undergone a long continued and gentle subsidence,
with few or slight upward movements and no important folding.

280

KNOWLEDGE.

Jl'LV, 1911

METEOROLOGY.

By John A. Curtis. F.K.Mf.t.Soc.

The weather of the week ended May iOth, as presented in the
Weekly Weather Report of the Meteorological Office, was
rainy at first, but became dry, though mostly dull.

Temperature was above the normal in all districts, the
greatest excess being in the Midland counties, where the mean
was 5-6 above the average. The highest readings recorded
were 73" at Norwich, and 71 at Kaunds and at Southampton.
In Ireland, X. the ma.ximum did not exceed 66'. The lowest
of the minima were 3i at West Linton on the 17th. and d-i' at
Balmoral on the 15th. Slight frost was recorded on the grass
at several stations, the lowest reading being 29° at Markree
Castle. Co. Sligo.

Rainfall was in excess in Scotland, E. and England. E., but
was in defect elsewhere, very greatly so in various parts, many
stations being rainless for the week. Sunshine was above the
average in Scotland, W. and Ireland, N. and was normal in
Ireland. S. In all other districts it was in defect. The least sunny
district was the Midland Counties with a total duration of
only 19 hours 117%! while the most sunny was Scotland, W,
with 56 hours (50%). The sunniest station was Castlebav,
Isle of Barra, which reported 70 hours of sunshine (61%).

The mean temperature of the sea-water round the coast
ranged from 55"-4 at Teelin and Seafield to 45"-8 at Scar-
borough, Thunderstorms were reported at several stations,
and during the early part of the week there was mucli mist or
fog on the coast.

The week ended May 27th was unsettled, with thunderstorms
and very heavy rains during the latter part. Temperature
was again above the normal in all districts, that with the
greatest excess being England, N.E., where the mean was 5"- 7
above the average. The highest reading reported was 81" at
Shaftesbury on the 27th. In Ireland. N.. the maxinunn was
only 66°, At Greenwich it was 7S\ The lowest minima for
the week were 29° at Balmoral and 30° at Llangammarch
Wells. On the grass the minimum fell to 24° at Llangam-
march, and to 25" at Crathes and at Greenwich.

In spite of very heavy local falls, the week's rain-fall was
below the average in all districts, and at many stations the
week was rainless. In England, E,, the total for the week
was only 0-01 inch as compared with an average of 0-44
inch. The thunderstorm rains towards the end of the week
were very heavy and caused Hoods in many places. .'\t Great
Billing, Northants, as much as 2-0 inches fell in one day, and
at Bere Alston, Devon, 2-5 inches was collected in one-and-a-
half hours.

Bright sunshine was in excess in most districts, but in
England, S.E.. and Ireland, X., it was normal ; while in Ireland,
S., it was slightly below The sunniest district was the English
Channel with a total duration of 73 hours (68%) while the
sunniest station was St. Mary's, Scilly, with 83-3 hours (76%).
At Westminster the total duration was 42 • 2 hours (38%). The
temperature of the sea-water ranged from 44 at Scarborough
to 58° at Scilly and Seafield.

During the week ended June 3rd. the weather was fine and
bright, but with many thunderstorms.

Temperature continued much above the average, and the
mean values in most cases were higher than any recorded
iri the corresponding week during the last thirty years. The
highest reading was 83° which was recorded at Fort William,
Balmoral and Aspatria. At several other stations readings of
80° or upwards were reported. The lowest of the minima
were 34° at Markree Castle on the 2Sth, and 35° at Balmoral on
the 29th, the same dav as that on which the maximum reached
83°,

On the grass, frost was experienced in Scotland, E., and
Ireland, N., the lowest reading being 28' at Markree Castle.
Rainfall was deficient nearly everywhere, and at quite a
number of stations the week was rainless. Some very heavy
thunderstorm rains were, however, reported, 0-92 inch at
Rothamsted, 1-00 inch at Greenwich, and 2-86 inches at

Epsom. Of this latter amount 2-44 inches fell between
5.20 p.m. and 6.10 p.m.. on May 31st.

Sunshine was above the average at each of the reporting
stations. The sunniest district was England, N.W., where the
mean was 90 hours (79%), while the sunniest st.ations were
Newton Kigg, near Penrith, 97-4 hours (84%), Stornowav
96-8 hours (80%) and Rhyl 96 -7 hours (85%). At Westminster
the total duration was 73-9 hours (66%). The temperature of
the sea-water was higher than usual, except on the South-
West coast of England. The individual readings ranged
from 47 at .Aberdeen to 62° at Seafield.

The weather during the week ended June 10th continued
very fine generally, though thunderstorms occurred in many
parts.

Temperature was still much above the average, an excess
being reported from every station. England, S.W.,was thedistrict
with the highest mean temperature, 61 • 8, as compared with the
average for the same district during twenty-fi%e years of 55° -8,
The highest of the maxima were 84'' at Fulbeck, Lincolnshire,
and Greenwich, with 83° at Tottenham, Westminster and other
places. The lowest of the minima were 34° at Llangammarch
Wells, and 35 at Newton Rigg. Blackpool and Glencarron.
In nearly every case the lowest reading was recorded on June
10th. In the Channel Islands the minimum did not fall
below 52°. Frost was still experienced on the ground, readings
as low as 25° being reported at Llangammarch and Burnley,
with 27° at Southport and Wisley. Rainfall was in defect in
all districts except the English Channel, where the excess
was due to a thunderstorm r.ain on June 8th, which
in Guernsey yielded between 1-1 inches and 1-7 inches. In
\ery many places (eighty-one stations out of a total of
one hundred and seven stations) the week was rainless.
Bright sunshine was in excess in all districts, especially
in the South of England and the West of Scotland, where
the mean total for. the district amounted to 86 hours.
The stations reporting the greatest duration were Brighton
99-8 hours (88 %) and Pembroke, 98-5 hours (86 %l, .\t
several other stations totals e.xceeding 90 hours were recorded :
Tenby 95-5 hours (84 %,), Douglas 94-4 hours (81 %), and
Worthing and Eastbourne 93-5 hours (83%). At Westminster
the total was 76-4 hours (68 %).

The sea temperature was much higher than in the corres-
ponding week of last year, and ranged from 49 ' at Lerwick to
67° at Seafield.

MICROSCOPY.

By A. W. Sheppard. E.R.M.S..

witli the assistance nf the folloicing inicroscopists : —

.\tMHLR C. Banfield, .\rthlr Eari^anh. F.R.M.S,

The Rev. E. \V. Bowf.ln, M..\. Richard T. Lewis. F.R.M.S.

James Ki'Rton. Chas. F. Roi-sselet, F.R.M.S

Charles H. Caffvn. D. J. Scolrfield, F.Z..S., K.R..\I..S.

C. D. Soar, F.L..S., F.R.M.S.

CYTOLOGY OF THE BACTERIA.— In the current
number of the Quarterly Journal of Microscopical Science,
Vol. 56, pages 395-506, appears an important paper on the
above subject by C. Clifford Dobell. The author's main
object has been to decide the question, whether or not the
bacteria are nucleate cells. In making the investigations
detailed in the paper the author selected certain large bacteria
found in the intestines of some animals : they belong to four
different groups, namely, cocci, bacilli, spirilla and the
so-called " fusiform bacteria." The method of preparation
described as the " drop " method, is said to be applicable also to
small infusoria and other protists. A drop of the material
to be examined is taken up on a platinum loop and placed on
a slip, by its side is placed another drop of one per cent.
Osmicacid or formol (forty per cent, solution of formaldehyde).
These two drops are intimately mixed and spread in a thin
film. When dry, no heat being applied for that purpose, the
film is treated with absolute alcohol — this is necessary in the
case where formol is employed as formaldehyde fixes proto-
plasmic structures without precipitating thcni in an insoluble
form,

July. 1911.

KNOWLEDGE.

281

From the facts detailed in the paper the author deduces the
following chief conclusions : —

All bacteria which have been adequately investigated are —
like all other Protista — nucleate cells. The form of the
nucleus is variable, not only in different bacteria, but also at
different periods in the life-cycle of the same species.

The nucleus may be in the form of a discrete system of
granules Ichromidia) : a filament of variable configuration; in
the form of one or more relatively large aggregated masses of
nuclear substance ; of a system of irregularly branched or bent
short strands, rods or networks: andprobablyalsoin the vesicular
form characteristic of the nuclei of many animals, plants and
protists. There is no evidence that enucleate bacteria exist.
Finally, in addition to these purely morphological conclusions
concerning the nucleus, the author thinks it is highly probable
that the bacteria are in no way a group of simple organisms,
but rather one displaying a high degree of morphological
differentiation, coupled, in many cases, with a life-cycle of
considerable complexity.

THE GENUS POLYTREMA iFOR.\MlXIFER.-\i.—
At the meeting of the Linnean Society, held on May
4th, Professor Sydney J. Hickson. F.R.S., communicated
a revision of the above genus. The discovery of some very
large specimens of Foraminifera belonging to the species
described by Carter as Polytrciiur cylindricuiit in the material
collected by Professor Stanley Gardiner in the Indian Ocean,
led the author to make a careful examination of this and of
other species attributed to the genus Polytrenia. The result
of this examination was to prove that the specimens usually
labelled Polytrciuci in collections may belong to three ([uite
distinct genera.

Polytrenia cylindriciiin of Carter is the type of a genus
for which the generic name Sporadotreiiia is proposed.
The specimen described by Carpenter under the name
Polytrenia rubra Lamk.. and many others that are labelled
Polytrema ininiaccuin Pallas, in collections, belong to
another genus for which the generic name Ho»;o/rc'/»(r is pro-
posed. The specimens described by Merkel. Lister and others
under the name Polytrenia niiniacciiin belong to a genus
distinct from the other tw^o. and for this it is proposed that the
generic name Polytrenia be retained.

A description of the principal characters separating the three
genera is given in the paper.

.\s regards the geographical distribution of the three genera,
it may be observed that Sporadotreina has only been found
in the Indian Ocean and on the Macclesfield f5ank in the
China Sea. that Polytrenia and Honiotrenia appear to have
a much wider distribution in temperate and tropical seas, but
atpresent the author has not seen any specimens of Polytrenia
from the shores of the American continent, nor has he seen
any specimens of the genus Honiotrenia from the Mediter-
ranean Sea.

COCCIDIOSIS IN GROUSE.— In an interesting paper
contributed to the current number of Science Progress.
Vol. \'.. pages 565-583. on the diseases of Grouse, Professor
.\rthur E. Shipley, F.R.S.. describes the complex life history of
Eiineria \Coccidiuin) avium, one of the seven distinct
unicellular or protozoan parasites which live either in the
intestines or in the blood of the grouse.

The chief source of contamination on the moors is the
droppings of other diseased grouse. The droppings contain
thousands of cysts (oocysts) or spores of the parasite and
these spores, with their hard coats, are extremely resistant
and can endure for very long periods w-ithout the death of
their contents, which gradually divide to form four smaller
spores (sporocysts) inside. The spores are scattered over the
moors by the action of the wind and rain and. alighting on
the heather or in the tarns of the moors, are taken up by the
grouse in their food or drink. When the cysts are swallowed.
they enter the gizzard of the bird and pass unchanged into
the first part of the intestine, called the duodenum. Here the
pancreatic juice is poured into the intestine, to aid in digestion.
and under its influence the cyst-wall is softened and dissohed.
and the four small spores (contained within the ripened spore

or oocyst) are set at liberty. Each small spore contains two
active motile sporozoites. which emerge from the softened
spore-case and proceed to penetrate the epitheliimi of the
duodenum. The young parasites ultimately cause the
destruction of the lining of the first part of the small intestine
— the region where, normally, the most active digestive pro-
cesses occur. The Coccidiiini parasities multiply in the
duodenal epithelium and then invade the caeca or "blind-guts,"
with disastrous results.

Sooner or later a limit is reached, on the one hand, to the
power of the grouse chick to provide nourishment for the
parasites, and on the other to the multiplicative capacity
of the parasites themselves. The Coccidiiini then begins to
reproduce sexually. Many small male parasites are produced,
together with larger food-containing female Coccidia. The
male and female parasites conjugate and then encyst, bursting
through into the cavity of the gut and giving rise to the spores
found in the caecal droppings on the moors.

PROTOZOA OF THE SOIL.— At the meeting of the
Royal Society held June 1st, 1911, a paper was read by T.
Goodey forming a contribution to our knowledge of the
protozoa of the soil.

It gives an account of work carried out on the soil protozoa
which .are considered to be chiefly instrumental in limiting the
activity of bacteria in the soil and thus in helping to render
the soil comparatively infertile. Methods of obtaining
protozoa in cultures of soil are described, and a list of the
different species found so far is given. An experimental
method for quickly finding the earliest ciliated protozoa
occurring in a soil culture is described, in which use is made
of the galvanot.actic response which many of the protozoa show
when stimulated by means of a continuous electric current.
By means of this method, active ciliated protozoa have been
found in from lA hours to 4 hours.

Experiments on the length of time required for a ciliated
protozoon Colpoda citcitlliis to develop from its resting cysts
ha\'e also been conducted in similar media and at the same
temperature as used in the soil cultures. It has been found
that the times required for development in both soil and cyst
cultures are comparable, and that the first Colpoda ciiciiltiis
to occur in soil cultures are almost identical in appearance
with those which emerge from resting cysts.

The conclusion drawn from the experiments is that the
ciliated protozoa are only present in the soil in the encysted
condition, and do not. therefore, function as the factor limiting
bacterial activity in the soil.

The protozoa of the soil are referred to in a paper by Dr.
H. B. Hutchinson (see "Knowledge" N.S. Vol. VIII,
pages 123-126.

(JUEKETT MICROSCOPICAL CLUB.— May 23rd,
igfl. Dr. E. J. Spitta, F.R.A.S., F.R.M.S.. vice-president, in
the chair. Mr. C. D. Soar. F.L.S.. F.R.M.S., read a paper
on "The work of the late Saville-Kent on British Hydrach-
nids." Together with Mr. Williamson, of Edinburgh, the
author is preparing a monograph of British Hydrachnids. and
had obtained from the British Museum (Natural History)
Authorities permission to examine all the slides, notes and
drawings which Mr, Saville Kent had brought together. The
collection was begun in 1S67. Mr. Soar found it possible to
identify forty species from the mounted preparations, and a
further ten from various notes and drawings. A detailed
list of the species identified is added to the paper.

A paper by Mr. E. M. Nelson. F.R.M.S., on " Methods of
Illumination" was read by the honorary secretary. Mirror
illumination was first dealt with. The proper way to centre a
concave mirror is : — First focus the object, then, looking at
the eye-lens, by moving the mirror, bring the image of the light
source central in the Ramsden disc. It is better to have centred
illumination even at the expense of an incompletely lighted
field. The use of ground glass then received attention, and
surprise was expressed at the appreciative remarks made by
Dr. Carpenter and Lewis Wright in their well-known books,
when discussing the use of this medium. After exhaustive
trials of ground-glass, and particularly in relation to its effect

2S2

KNOWLEDGE.

July. 1911.

on the image. Mr. Nelson summed up the result by one word
— " Fog." — The simplest condenser, even a single lens so used,
gave a better image than could be obtained with ground-glass.

Sir D. Brewster, in 1S36, was the first to employ colour
screens in microscopy. Mr. Nelson recommended the use of
a screen composed of a piece of peacock-green glass combined
with a very light blue for visual daylight work, and for lamp-
light a piece of thicker peacock-green glass combined with a
blue glass of the tint of the blue cornflower. Reference was
also made to the various forms of Gifford's screen and to that
used by Dr, Miethe.

One other form of illumination dealt with by Mr. Nelson is
that of using part of the spectrum. A prismatic spectrum is
brighter than that given by a diffraction grating, although on
the other hand, the dispersion obtained with a fourteen
thousand line grating between E and G in the first order is
more than double that of an ordinary flint-glass prism.

The Chairman in asking the meeting to pass a very hearty
vote of thanks to Mr. Nelson, made some very appreciative
remarks on the " M " series of screens issued by Messrs.
Wratten and Wainwright. He considered them almost
indispensable to the careful worker, as they afforded full
control of the colour of the lighting and consequently of the
amount of contrast obtained with all classes of coloured
objects.

THE ROYAL MICROSCOPICAL SOCIETY. — Mav
17th, 1911. H. G. Plinuner. Esq., F.R.S., President, in the
chair. Mr. J. E. Barnard made a connnunication on a
method of disintegrating bacteria and other organic cells.
The author first mentioned that bacterial to.xins were of two
kinds, extra-cellular and intra-cellular. The former were
excreted into the medium, e.g., beef broth, in which the
organism was cultivated, so that by a process of filtration the
organism could be removed and the toxin was obtained in the
filtrate, but the majority of pathogenic micro-organisms did
not excrete their toxins, at least to any great extent, and the
toxins were retained within and formed integral parts of the
cells of the organisms.

One method of obtaining these toxins was to mechanicallv
disintegrate the bacterial cell, so that the cell contents were
expressed, and the apparatus described accomplished this.

It consisted essentially of a containing vessel in which, by a
suitable rotation of steel balls, the organisms were crushed.

The principal conditions to be fulfilled in such an appliance
were : —

(1) ."Vpproxiuiately e\ery cell should be brought under the
grinding action.

(2) Little or no rise of temperature should take place.

(3) The disintegration should be carried out in a vessel
which was sealed so that, when dealing with pathogenic
organisms, none could escape at any stage of the process.

These conditions were, in the main, complied with in the
apparatus described. Experiments indicated that by this
method the cell juices were obtained unaltered, and so were
suitable for investigation on the chemical composition and
properties of the bacterial proteins and other cell constituents.
Also that, after the grinding process had been carried on for a
sufficient time, practically no cells remained which could be
properly stained by any recognised bacteriological method, and
which, therefore, conld be regarded as whole cells containing a
normal quantity of cell juice.

Mr. James Murray presented a third portion of his report
on the Rotifera observed by the Shackleton Polar Expedition
of 1909, dealing with the new species, and so on, from the
Pacific Islands. He said that in Fiji fifteen Bdelloid Rotifera
were collected, in Hawaii twenty-four, ten species being
common to the two groups of islands.

In Fiji two new species were dislingnished. Callidina
pacifica and Hahruiroclia nodosa, the latter previously
known, as a variety, in India, and elsewhere.

In Hawaii there were no peculiar species, but some very
distinct varieties.

In the various Pacific Islands there have been recorded
thirty-one species of Bdelloids.

The attention of the Fellows of the Society was then directed
to the collection of specimens of Pond Life, which had been
arranged for the evening.

OKXITHOLOGY.

By High Boyd \\.\tt. M.B.O.U.

THE DISTRIBUTION OF THE NIGHTINGALE IN
GREAT BRITAIN DURING THE BREEDING SEASON.
— Discussion of this subject is revived by an article contributed
to the June number of British Birds (Vol. V., No. 1, pages
2-211. by Mr. N. F. Ticehurst and the Rev. F. C. R. Jourdain.
The chief value of the paper lies in the carefully worked
out details given under those counties in which the distribu-
tion of the species is local, or which mark the limits of its
range in England and Wales. This faunistic information is
very valuable and full, and summarises present-day knowledge
on this part of the subject, making clear the well-known and
curiously partial character of the bird's distribution. Com-
menting on the last-named point, the writers express the opinion
■■ that the real obstacles which prevent the general distribution of
this species over the greater part of England and Wales are
the ranges of elevated land, which it instinctively avoids."
This seems adequate only in so far as it is limiting and
negative in character, and the condition laid down is in no
way peculiar to the Nightingale. Height of land is a factor
which affects the distribution of species generally, but many
other considerations come in. That the Nightingale is not
found on elevated land, and that its distribution is restricted
or limited by such elevations, may account for its absence
there ; but this reason seems an incomplete explanation of
its presence in its frequented haunts and known stations, and
not in contiguous places where the conditions are apparently
similar. It would seem that Professor Newton's judgment must
still stand. \iz. : — " No reasonable mode of accounting for the
partial distribution of the Nightingale has hitherto been
propounded " \" Dictionary of Birds." 1903-6, pages 339-3401.

THE BIRDS OF ST. ALBANS.— This famous old
city, like the county in which it is situated, has rather a
meagre avi-fauna, due, chiefly, to the absence of maritime
conditions. Nor does there seem to be any great fly-line of
migrants across the county from which records might be
gathered. Hertfordshire birds number about two hundred
and ten species in all, and the St. Albans list includes one
hundred and twenty-eight of these. Mr. W. Bickerton gives a
good account and classification 'for the city and a radius
of five miles around) in a work entitled "St. .-Mbans and
its Neighbourhood" (1911), published by the Hertfordshire
Natural History Society, in connection with the .\nnual
Congress of the South-Eastern Union of Scientific Societies
recently held in that city. Mr. Bickerton's article (pages
240-243) lays a sound basis for further observations and
bird-study in the district.

ACCOUNTING FOR THE ROOK.— The thinning-out
of the Rook, recommended by some authorities, is not neglected
in some districts. For instance. Mr. C. C. Ellison,
Bracebridge, Lincoln, writes to The Field that one day's
shooting each year for thirty years on the same estate has
produced 20,793 Rooks. The biggest bag was 1,220 to seven
rifles : the best was 1,210 to two rifles only. Mr. Ellison adds
that there are probably not half the Rooks in the country now
that there were in 1H80.

TH£ BOYD ALEXANDER COLLECTIONS.— The
great collections formed by the late Mr. Boyd Alexander on
his .African expeditions, and bequeathed by him to the Natural
History Museum, South Kensington, have now been h.anded
over to that institution by his executor. Mr. Robert .\lexander.
They comprise nearly four thousand bird-skins of .African
species, and include the type-specimens of no fewer than eighty
species.

JlT.V, 1911.

KNOWLEDGE.

283

ANTARCTIC BIRDS.— The Scottish National Exhibition,
now open at Glasgow, contains a section illustrating the
Antarctic Expedition of the " Scotia." There is a good display
of the birds and seals of the .Antarctic, shown in artistic
representations of their natural surroundings. One of the cases
represents a scene in the South Orkneys, and conveys a \'ivid
impression of Antarctic bird life. Five species of penguins,
with eggs and young, are represented. Notably there are
three Emperor penguins, standing in solitary state on an ice
floe, one of them trumpeting a love-song to his mate. .Among
the smaller birds, the most prominent are black-throated or
adelia penguins. A pair are seen hurrying back to their nests
after ha\ing had an excursion to sea in search of food. .An
anxious mother is seen feeding her young, while another pair
sit expectant alongside an unhatched egg. There are also the
gentoo penguins, with red-marked bills and white-striped
heads : the macaroni penguin of the golden crest, and the
ringed penguin.

Twelve other species of .Antarctic birds are represented.
These include the blue-eyed shag, in its nest of seaweed ; the
Dominican gull, resembling the black-back gull of our own
waters ; and the fierce skuas fighting over the body of a
penguin. The only land bird of the .Antarctic, white and in
form like a chicken, is also shown. Then there are the petrels.
— the giant petrel, sitting on its nest of stones ; the silver
petrel, the .Antarctic petrel, the blue petrel, and the snowy
petrel, whose presence is indicative of the ice pack. There is
a fine specimen of the mottled black and white Cape pigeon,
whose eggs the " Scotia " naturalists were the first to discover,
although the bird has been known for at least three hundred
years.

PHOTOGR.M'HY.

Hy C. E. Kenneth Mees. D.Sc, F.C.S., F.R.P.S.

THE FOGGING POWER OF DEVELOPERS.— A paper
on this subject appears in the June number of the
Pliotojiraphic Journal. It is. of course, well known that
developers differ in the amount of fog which they produce on
unexposed plates, but this appears to be the first systematic
attempt to compare the fogging power of different developers
and to distinguish the conditions which tend to produce fog in
development. In order to compare the fogging power of
different developing solutions, it is necessary to measure the
amount of fog which they will produce in the time necessary
to produce a given degree of contrast.

In the development of an exposed plate, the rate at whicli
density grows is usually expressed by what is called the
" velocity constant," which quantity may be denoted by the
symbol K. (See "' Knowledge """ Notes," May. 1911.) The
value of K for a given plate and developer is easily determined
and if we can find some equally simple means of determining
and expressing the rate at which fog grows in an unexposed
plate, it is obvious that a comparison of the two constants
should gi\e an idea of the fogging power of the de%elopcr
used.

For example, if the rate of growth of fog on an unexposed
plate is exactly equal to the rate at which the density grows in
exposed parts of the same plate, it is obvious that no image
can result, the fogging power being so great that we can only
obtain a uniform deposit over exposed and unexposed portions
alike. A developer giving such a result will be useless, and it
is in all cases necessary that the velocity of the fogging action
shall be less than that of development.

If we express the fogging velocity by the symbol F. just as
we express the developing velocity by the symbol K, then the
ratio of F to K can be taken as a measure of the fogging
power of the developer, and therefore we may measure F and
K separately, and then, dividing F by K, obtain a quantity
which can be used as a measure of the fogging power.

In the production of measurable degrees of fog on
unexposed plates very considerable duration of development
was necessary and, as any oxidation of the dexeloper aflccted
the results, the plates were developed in a tube which was
quite full of developer, a rubber cork fitted with a stop-cock

being pushed in until the developer spurted out from the
stop-cock, which was then closed. In order to avoid
temperature errors, the tuV>e was a vacuum-jacketed Dewar
tube.

The developer used was Hydroquiuone and Caustic .Alkali
and the results obtained showed that the fogging power of
such a developer is mainly due to two causes — oxidation
products of the developer itself, and the sodium sulphite used
as a preservative. The fogging power of non-oxidised
developers not containing sulphite was independent of the
amount of alkali present, increase of the alkali increasing the
development of both exposed and unexposed bromide in the
same proportion, leaving the ratio unaltered.

The oxidation product of the hydroquiuone developer,
quinhydrone, was found to be a powerful fogging agent in the
presence of alkali, developing exposed and unexposed bromide
at the same rate and conse(|uently developing no image on an
exposed plate. Since this compound cannot exist in the
presence of sodium sulphite ordinary photographic developers
do not give oxidation fog! But sulphite itself is a source of
fog, the amount of fog depending on the concentration of the
sulphite and rising to a maximum at a low concentration,
decreasing again as the concentration is increased.

The explanation given by the authors for the phenomena
described by them is based on a discussion of the reduction
potential of developers.

The reduction potential of a reducer, or the oxidation
potential of an oxidiser is the analogy for chemical affinitv of
electric potential in electricity.

On the other hand, the resistance potential of a chemical
substance (Cig., silver bromidel may be compared to the " back
potential " of an arc lamp. It requires a certam voltage
(about forty volts) to enable an arc with carbon poles to burn,
and if the potential of the source of electric energy is lower
than this, then the arc will not burn.

If iron poles are used in the arc a higher potential labout
sixty-five volts) is required to enable the arc to burn; so that
there is a range of voltages (from forty to sixty-five volts)
where carbon arcs can burn but iron arcs cannot.

The authors suggest that the difference between fogging
agents and developers is analogous to this difference between
the voltages, which will work arc lamps with different poles.
.A substance with a low reduction potential (e.g., neutral
hydroquiuone) cannot reduce either exposed or unexposed
silver bromide. If the reduction potential is higher then
exposed silver bromide becomes dexelopable. but the
resistance potential of unexposed silver bromide is still too
high. All substances which have reduction potentials higher
than the resistance potential of exposed silver bromide, but
lower than that of unexposed silver bromide will be developers.
If the reduction potential of a substance is higher than the
resistance potential of unexposed siher bromide (as is the case
with alkaline i|uinhydrone, for instance) then it will be a
fogging agent.

Any substance which tends to lower the resistance potential
of unexposed silver bromide will increase the fogging power of
a developer, and. since the resistance potential of a substance
depends upon its insolubility, any substance, such as sulphite,
which increases the solubility of silver bromide will increase
the fogging power of a developer, while a substance, such as
an alkaline bromide, which decreases the solubility will
decrease the fogging power.

The subject would seem to require a good deal more
investigation and probably the theory outlined abo\e will
require nuich modification, but it is s.atisfactory that some
progress is being made with a subject about which so little
has hitherto been known.

PHYSICS.

By A. C. G. Egi.rton. B.Sc.

Physicists have had the opportunity of examining tlie fruit
of each other's work during the past month. The Physical
Society has enjoyed the opportunity of visiting the National
Phvsical Laboratory : while the Conversa/iione of the Royal

284

KNOWLEDGE.

July, 1911.

Society, on May 10th. included exhibits of very great interest.
Further than this, many illustrious men from foreign countries
have honoured their scientific cousins with their presence in
this country, strengthening thereby the absolute internationality
of science. Among these one may mention Professor Svante
.\rrhenius, Professor Richards and Professor Wood. It will
be well this month to note shortly a few of the contrivances
which have thr6wn light on the subjects recently investigated.

Professor Wood, in a lecture to the Royal Institution, on
Friday, May 19th, described many experiments which he has
made on ultra-violet light. Using (juartz lenses and silvering
them with a uniform coating of silver, he has been able to
photograph objects by ultra-violet light: the silver absorbs all
the visible light. In such photographs the sky is very bright : the
ultra-violet light gets scattered by the atmosphere to a very great
degree, so much so that no shadows appear. Many quite white
bodies, such as Chinese white and most garden flowers, do not
reflect ultra-violet light, and so appear black. Professor Wood
has photographed the moon by ultra-\iolet light, and obtained
patches which show e.xceptional absorption. To exhibit this,
he had reconr.se to the ingenious method of projecting two
photographs on to a screen so that the two images were com-
pletely in register and superposed. The one photograph is
taken b\- ultra-violet light, the other by ordinary light. A red
filter is placed in front of one photograph and a green in front
of the other, so that any difference in the two is at once
detected by a preponderance of red or green light on the
screen, instead of a complete neutralisation of the two com-
plementary colours. With infra-red light there is no scattering
by the sky, which appears quite black in photographs taken
through a screen of cobalt glass and certain organic dyes
which cut off all light of shorter wave-length than A 6S00,
But the leaves of trees reflect this deep red light almost
completely. These effects were dealt with more completely by
Dr. Mees in " Knowledge " a few months back.

Professor Wood has been able to isolate short ultra-\iolet
waves from a magnesium spark by a system of quartz lenses.
The centre portion of one of the lenses is stopped out
altogether, while the distance apart of the lenses is so
arranged that the ultra-violet light alone can pass through
the outer portion of the second lens, the more refrangible
rays being stopped from passing by the centre blackened
portion of the lens. There is another way of isolating the
ultra-violet waves alone, but this latter method only obtains
the more refrangible of these rays : those which can penetrate
glass. A screen made of nitrosodimethylaniline combined
with a cobalt glass attains this object.

Messrs. Wratten and Wainwright supply such light filters.
Their list includes colour filters for many purposes, such
as the isolation of the green mercury line ; a screen which
in combination with a mercury lamp gives an absolutely
monochromatic beam. The balancing of the colours in the
tricolour screens is very perfect and they should have many
applications ; the researcher, the lecturer, the photographer
and the microscopist will find many uses for them.

Lord Rayleigh has pointed out that transparent objects are
only visible when they are illuminated unequally. Kaufmann
has devised a simple [nethod of illustrating this point. .A
funnel of white cardboard is illuminated inside by a glow lamp
and vertically up the axis of the funnel is fixed a glass rod.
Looking through a slit in the side of the funnel the rod is
invisible until it or the lamp is shifted to one side of the axis of
the funnel. A transparent object immersed in a fluid of the
same refractive index is invisible; for instance, the end of a
glass rod is invisible when dipped in Canada balsam (or. better,
in a solution of eight volumes of chloral hydrate in one volume
of glycerine) while, when withdrawn, the end appears to melt.

When using interferometers it is often very difficult to
obtain sufficient magnification of the bands of light obtained
without too great a loss of light. Lord Rayleigh some years
ago devised a most ingenious way of getting over this
difficulty. He constructed a telescope with a cylindrical lens
as an eyepiece and a lens tilted at an angle to the vertical
plane as object glass : in this way he obtained a telescope
magnifying in only one direction.

It is only possible to compare intensities of light definitely

when the light is of the same colour, i.e., of the same wave
length. The comparison of differently coloured sources
should be made by means of a spectrophotometer — a spectro-
meter with a Nicol prism which, on rotation, cuts oft" more or
less of the light of any particular wave length. The numerical
value of the total intensity of any light source may be obtained
from the monochromatic intensities by allotting to each colour
a co-efficient, and then summing up the intensities obtained
thus for all the colours. M. Thovert has recently worked
on these lines and has selected the distinct vision of form as
the basis from which to deduce the value of these co-efficients.
This method is preferable to that based on obtaining a colour
sensibility curve. In the one method a grating spectroscope
is used, and a monochromatic ray is isolated by means of a
slit, and the luminosity regulated by suitable means ; a
pattern is placed in the path of the light at the limit of
distinct vksion. and the wave lengths found for any particular
degree of illumination for which the pattern is just \isible.
The other method is dependent on finding the extreme wave
lengths visible when the light from a spectrum is shielded by
grey-tinted glass of different depths. There are many
problems of great interest in photometry of light of different
colours, the subject of colour blindness being intimately
connected with it. We must return to the question in another
issue.

The measurement of resistance of a mercury column has
been employed by T. R. Merton to calibrate capillary tubes,
always a troublesome proceeding when done by measuring
the change in length of a pellet of mercury. The ends of the
capillary tube communicate with two mercury cups which are
connected to one arm of a Wheatstone's bridge. The mean

., l + -'dr
raduis r is given by r"= 7— where 1 is the length of the

capillary, f the found resistance and d a correction for the
stream lines at the ends of the capillary, k the specific
conductivity of mercury. It has occurred to the writer that
measurements of volume in gas burettes might be made by
inserting an iron resistance wire down the burette inside so
that the mercury uncovers more or less of the wire as it is
raised or lowered, the change in resistance of the wire being
accurately measured.

Professor Theodore Richards has employed a method of
electrical contacts for measuring volumes very accurately. As
the mercury is lowered so it can be set to just make or break
an electrical contact consisting of a fine platinum point. He
has used the method to determine dift'erences in the com-
pressibilities of liquids.

Mr. E. H. Rayner has recently described an ingenious
arrangement for measuring small thicknesses and displace-
ments with far greater sensitiveness than the micrometer will
attain to. It consists of three conical feet, two in one
plane and the other half-way between them, but slightly
out of the plane, so that they rest in a hole, slot, and
plane at the corners of a very obtuse angled triangle.
The three feet are affixed at the upper end, to a lever
carrying a concave mirror focussing a spot of light
into a screen. Any slight shift of the third foot, the
one that lies slightly out of the plane, causes a slight
rotation of the lever, which is magnified considerably by the
spot of light. The author has employed the apparatus to
measure the expansion of short bars of quartz, only fifteen
centimetres long ; also uses are found for it in measuring
thicknesses of mica, paper and foil ; or, again, as an adjunct to
a chemical balance, to obtain a first approximation to the
weight. In the Latter case the three legs of the tilting table
are affixed to the end of three rods fitted at their other ends
into a block of metal. The centre rod, on being bent by
affixing a weight to it, will then tilt the table proportionally to
the weight applied and the position of the weight on the rod.

In Messrs. Paul's recent catalogue there are to be found
two instruments of considerable interest which have been
designed and placed on the market. The one is a thermoelectric
junction and unipivot galvanometer combined with a special
compensator patented by .Mr. C. R. Darling. This com-
pensator eliminates any error due to the heating of the cold
junction, ."^ny change in the temperature of the cold junction

Jc'i.v. 1911.

KNOWLEDGE.

285

is compensated for by means of a metallic thermometer which
iwists the spring of the unipivot galvanometer so as to
connteract the inaccuracy of the reading due to this change
of temperature of the cold junction. Thus the instrument
can be employed without any corrections to read conveniently
any temperature, being specially adaptable to the measurement
of low temperature, e.g.. refrigerators, and so on.

The other instrument, the " Ampall" we must leave till next
month to describe.

ZOOLOGY.

By Professor J. Arthur Thomson, M.A.

BIOLOGY OF A HAY I MUSION.— Everyone knows
that a ■■ hay infusion '" becomes a little world teeming with
animal and plant life, and that it goes through a cycle of
changes, form after form rising into dominance and then dis-
appearing. Professor L. L. Woodruff, who has made so
many interesting studies on Paraitioccitini, has begun a series
of precise studies on the biology of the hay-infusion, by
devoting himself particularly to what happens in the case of
this infusorian. " The interdependence of the organisms of a
hay infusion is so complex that, taken as a whole, it is almost
beyond the possibility of analysis, and accordingly the logical
method of approach to the subject is to study the interaction
of isolated organisms and small groups of organisms on them-
.selves and on each other." His first question was : " How is
Pitraiiioeciiini affected by different volumes of the culture
medium ? " and his answer is that the greater the \olume the
more rapid is the rate of division. He went on to enquire into
the effect of changing the culture-medium, and found evidence
that Paraiuoeciiini excretes substances which are toxic to itself
when present in its environment. These substances are more
effective when the organisms are confined in limited volumes
of culture fluid. These poisonous excretion-products play an
appreciable part in determining the period of maximum
numbers, the rate of decline, and so on. of Paraiitocciii m in
the " hay-infusions."

AN INTERESTING MARINE HELIOZOON.— Some
years ago. Sassaki described a large Heliozoon. Gyiiino-
sphacra albida. which occurred in the salt water aquarium of
the Zoological Institute at Munich. It was supposed to
have been transported from Kovigno. Maurice Caullery has
been fortunate enough to rediscover Gyiiinospliaera on
seaweed at Banyuls, and he adds some notes to Sassaki's
description. It is a large Protozbon, easily visible to the
unaided eye ; it has long pseudopodia which sometimes
anastomose ; and it may have as many as twenty or thirty
nuclei. In some cases it armours itself with numerous
borrowed spicules of sponge and Holothurian.

LUMINESCENCE OF FIRE-FLIES.— Notwithstanding
numerous investigations there seems to be still a great deal to
be discovered in connection with the luminescence of fire-flies.
F. A. McDermott and C. G. Crane have been recently studying
some of the American Lampyrids. They find practical
identity in the structure of the light-producing organs in these
beetles, which are popularly called fire-flies. The organ has
two layers, an inner one. white and opaque, which seems to
serve as a reflector, and perhaps protects the insect from its
own brightness, and an outer one, yellowish and translucent,
which is the seat of the actual photogenic process.
Physiological work led long .ago to the conclusion that the
photogenic process was of the nature of an oxidation, and this
is corroborated by the study of the structure, e.g.. by the
demonstration of the innumerable tracheae which penetrate
the organ.

RHYTHMS OF ACTIVITY AMONG TERMITES.—

It is probable that there is a rhythmic character in animal
activities to a greater extent than we as yet realise. Internal
rhythms have been established in the course of ages in
adaptation to external periodicities. But it does not, of
course, follow that there is greater activity during the day.
In a termites" nest, for instance, .Andrews and Middleton have
shown that there is about five times as much a-doing. as
expressed by the traffic in the arcades, in the greatest bustle
of night work as in the greatest ebb of noon. With great
patience they counted the comings in and goings out. " In
one case the number of termites going into the nest each hour
varied from 1,702 between 1 and 2 p.m. to 8,100 between 1 and
3 a.m., while in the same case the numbers going out of the
nest w-ere 1,194 between 12 and 1 noon, and fi,820 between
1 and 2 a.m." The curves show that the termites work at all
hours of day and night. Yet there are distinct rhythms in the
activities of the entire community.

DISSEMINATION OF DISEASE BY HOUSE-FLIES.
— The part that is played by flies in disseminating tropical
diseases is well known, and our house-fly is a typhoid distribu-
tor. In regard to another common fly. the Biting P~ly
[Stomo.vys calcitrans\, it has been recently proved by
Prof. A. Schuberg and Dr. Ph. Kuhn that if it is itself
artificially infected with deadly Trypanosomes and Spirochaets,
it can transfer these to higher animals.

SYMBIOTIC MICRO-ORGANISMS IN A CATER-
PILLAR.— In many animals there are minute inmates of the
food-canal which have a useful action on the food. There are,
for instance, some beautiful Infusorians which seem to be
always present in the horse's intestine, helping in the breaking
down of the hay and other food-stutfs. Some other animals
are known to have a friendly contingent of intestinal bacteria.
P. Portier has been working lately at the interesting caterpillar
of Xoiiagria typliae. which feeds inside the stem of bulrushes.
The digestive area is very restricted, and no ferment able to
digest cellulose could be found. But there was great
abundance of minute " pseudo-bacteria ", prob.ably small
moulds, which work at the vegetable tissue, breaking it
down. They pass through the wall of the intestine and are
engulfed bv the caterpillar's amoeboid blood corpuscles. The
case requiries further investigation, but it looks like a genuine
partnership, as if the "pseudo-bacteria" weie middle-men
between the animal and its food.

MOUNTING MINUTE ARTHROPODS.— In spite of
many recipes it is often difficult to make a satisfactory business
of mounting minute Arthropods, such as small Diptera,
Hemiptera. and Acarines. Maurice Langeron recommends
very strongly the following method. He kills the specimens in
hot alcohol, and after a few minutes transfers them to
■■ chloralphenol," either in a large drop on a slide or in a little
tube. This secures clearing and dehydration, and the
specimens can be transferred directly to balsam dissolved in
x\lol. The lluid that works so well is .Amann's chloralphenol.
It may be prepared by mixing two parts of hydrate of chloral
with one part of phenol, or by mixing equal parts of para-mono-
chlorophenol and hydrate of chloral. The mixtures are
liquefied at a gentle heat.

INCUBATION OF CYCLAS EMBRYOS.— It is well-
known that these develop in the shelter of the inner gill-plate.
The incubatory sacs have been recently studied in detail by
PoyarkofI'. who brings out the interesting point that they are
in the main due to leucocytes. In other words, they arise by
a process analogous to inflammation and the gill-lamella
requires some patching afterwards, especially as regards its
ectodermic epithelium.

44. COLOURS OF THE SPECTRUM.— Can the green
part of a spectrum be divided into yellow and blue ? If so.
how is it that the prism does not cause the vellow to fall
within the yellow limits, and the blue within the blue limits,
leaving the green position blank ? If not, can every colour

OUF.RIHS,

of a definite wave

length be called .i " Primarv colour " ?

H. T.

45. HEAT .\ND A V.\CUUM.— If heat can travel over a
vacuum, how is it that a vacuum flask prevents a liquid from
cooling r H. F.

286

KNOWLEDGE.

Jl-i.Y. 1911.

46. GLOBE LK.HTXINc;. — I stated recently in
conversation as a positive fact the existence of the
phenomenon called " Globe Lightning," and described as a
luminous ball which moves slowly and finally explodes with
violence. The assertion was warranted by te.xt-books of
Meteorology, published not very long ago, Isut in the new

edition of the " Encyclopaedia Britannica " I can find no
reference to the subject.

Can you or any of yoiu' readers kindly inform me whether
the phenomenon is now discredited and must take its place,
" ith '■ the all-dreaded thunder-stone," among the myths of
popular science ? A. V. W

REVIEWS.

BOT.AXV.

.4;; hitrodnction to \'cj>ctablc PUysiolojiy. By J.

Km.Noi.DS Greek. 470 pages. 1S2 illustrations.

9-in.X5^in.

(J. & A. Churchill. Trice 10 6 net.)

Professor Reynolds Green's book on Phvsiologv first
appeared some ten years ago, and the third edition which has
now been brought out has been altered considerably in the light
of the experience gained in the interval, while the progress of
science has rendered it necessary to re- write certain sections.
The chapter on the differentiation of plant body has been
expanded and, generally speaking, the author has set himself
throughout to combat an idea which has arisen during the last
few years that many alterations may go on in protoplasm
" without involving any interchange with its substance."

CHEMISTRY.

Science and the CniiiiiiaJ. — By C.
240 pages. Illustrated.

(Sir Isaac Pitman & Sons.

.AlXSWORTH MnCHELL.

/■!. -in. X 5-in.
Price 6/- net.)

Readers of " Knowledge " ha\e long been familiar with
Mr. Ainsworth Mitchell's writing, and know that he is an
expert on the subjects of inks and the age of handwriting.
They will thei'efore be prepared to find that Mr. Mitchell has
produced a very interesting and readable \olume, not only in
the directions indicated, but on the whole cjuestion of the
relationship of science to the criminal.

In his introduction he cites a case where the whole of the
chemical and medical evidence in connection with a poisoning
trial was, on the advice of the judge, submitted to an independ-
ent scientific authority, with the result that six reasons were
given pointing to the guilt of the accused, while eight were in
the opposite direction. Mr. Mitchell claims that there is
abundant justification for the plea that the poor prisoner
should have the same advantages as regards scientific assist-
ance as he now possesses in legal matters, and thus be placed
on an equality with the wealthy prisoner. He further adds
that it ought not to be a dififlcuit matter to draw up a list of
men of recognised standing in chemistry .and medicine who
would be willing to serve in this capacity when selected b\-
the judge in a trial.

The first part of the book deals with methods of detection,
capture and identification, and shows how science makes it
increasingly difficult for the guilty to escape. Interesting
details are given concerning trials in which scientific evidence
has proved of importance, and a chapter deals with identifica-
tion of human blood and human hair, which will prove of
interest to the biologist. The book, however, as a whole,
cannot fail to be attractive both to the scientific and to the
general reader.

The Mechanism of Life. — Bv Dr. Stephake Leduc.
1 11 pages. 64 illustrations. ')-in. x 6-in.

(Rebman Limited. Price 6 - net.)

We have already reviewed Professor Leduc's " Theorie
Physico-Chimique de la Vie et Generations Spontanees," of
which the present volume is an English Translation made by
Mr. Deane Butcher, and revised and corrected, as well as in
many places re-written, by the author himself. Mr. Deane
Butcher has from the beginning taken the very greatest
interest in Osmotic gnnvths, which he has experimented with

himself, and of them he says there is no more wonderful and
illuminating spectacle. " A crude lump of brute inanimate
matter germinating before our eyes, putting forth 'Dud and stem
and root and branch and leaf and fruit, with no stimulus from
germ or seed, without even the presence of organic matter.
For these mineral growths are not mere crystallizations, as
many suppose ; they increase by intussusception and not by
accretion. They exhibit the phenomena of circulation and
respiration, and a crude sort of reproduction by budding ; they
ha\e a period of vigorous youthful growth, of old age, of death,
and of decay." We congratulate Mr. Deane Butcher on his
successful attempt to put the question before the British
scientific public.

ENTOMCJLOGV.

Ttie Lore of the Honey liee. — By Tickner Edwards.
72 pages. 1 illustration. 7-in. x 4 {-in.

(Methueu & Company. Price 1 - net.)

To those who are interested in Natural History generally, or
in Bees in particular, this little \olume will prove most attrac-
tive. Although it contains much solid information it is j-et
written in a way that encourages one to read on. and it is
historical as well as biological and apicultural.

Our Insect I-^'riends and Foes. --By F. Martin Duncan.
296 pages. 16 plates. 74-in. X5-in.

(Methuen & Company. Price 6 -.)

The facts of natural history never become dull, and though
writer after writer brings them before us and even chooses
the same themes, they never become tiring. For each
naturalist puts them before us in his own way, dwelling on
something which has not been emphasised before, adding
sometimes to the store of knowledge and, may be, putting a
new interpretation upon old and familiar observations. Mr.
Martin Duncan is well known to many as a lecturer who puts
before others the things which interest him in a quiet but
efl'ective and convincing way. In dealing with the subject of
insects (in connection with which he has done much work),
whether it be the useful burying bettles, mimicking butterflies,
the forms which are of value in commerce, or dangerous
by transmitting diseases, he is always lucid, accurate and
entertaining.

GEOLOGY.

Geo!of>y for Engineers. — By Lieut. -Cor,. R. F.Sorseie, R.E.
423 pages. 94 illustrations. 8-in. X a'r-in.

(Charles Griffin & Co. Price 10/6 net.)

This is an ill-balanced book. The first part, dealing with
theoretical geology, is a thorough and painstaking compilation
from authorities, many of which, as can be seen from the list
of works consulted, are antiquated and now only of historical
value. Consequently, this part contains many curious slips
which would have been avoided had the author kept his
knowledge of the science up-to-date. The second part treats
of the practical application of geology to various engineering
problems, such as water supply, building materials, roads,
canals, rivers, and coast-erosion. In this the author is
evidently at home, and has produced a practical manual of
the utmost value to engineers, who have too often to regret
their small amount of geological training. This part is indeed
so good that it is a matter for regret it was not expanded so as
to fill the entire \'olume. The need for which the first part

Jri.v. lOll.

KNOWLEDGE.

287

was written could have been met by a reference to modern
elementary text-books, or by a recommendation to the student-
reader to take a class in elementary geology. Misprints
are commendably few, although we read " rainful " for
■■ rainfall "' on page 240. .\ full and accurate index is
provided. q ^^- -p

The Sticdenfs Lycll. — By E. John \V. Jldd, F.K.S.
645 pages. 736 illustrations. 8-in. XSi-in.

(John Murray. Price 7 6 net.)

We welcome the appearance of the second edition of " The
Student's Lyell" edited by Professor Judd. which the latter
has corrected and endeavoured to bring up-to-date. In
Professor J udd's words : " Now that the doctrine of Evolution —
as applying alike to the Inorganic and the Organic world — is
universally accepted, the writings of Lyell. who was truly
"the Forerunner of Darwin." actjuire a new interest and are
inxested with a permanent \'aluc. The " Origin of Species ' has
been justly asserted by Huxley to be ' the logical sequence to
the " Principles of Geology" ' ; it has therefore seemed iitting to
prefix to a new edition of the present volume a histor>- of the
events which led up to the production of Lyell's epoch-making
work."'

The Gcoloiiy of Building Stones. — By J. .\li.en Howe.
B.Sc. F.G.S. 455 pages. 46 illustrations. 72-in.x5in.

I Edward .Arnold. Price 7 6 net.!

This is the fourth volume of Arnold's Geological Series,
and. like the preceding ones, deals with a particular aspect
of economic geology, the growing importance of which is urged
in the breezy introductory chapter to this work. .\ brief
survey of the rock-forming minerals is first given. An
account of igneous rocks, sandstones, grits, limestones and
slates follows, in which, while the purely scientific side is not
forgotten, emphasis is placed on the various practical aspects
appealing to the architect and engineer. Notes on the distri-
bution of the various types are given, and. naturally, most
space is allotted to rocks occurring in the British Isles. Much
useful information, hitherto hard to get, is contained in the
chapter on the decay of building stones. The book closes
with an excellent section on the testing of building stones,
giving a resume of all known methods, and estimating their
comparative values. This is a most valuable part of the book,
for, as the author says, architects are deterred, by the fear of
risk, from using manx' good stones with which they are
unfamiliar, because no reliable tests have been made of these
materials. Some appendices contain lists of quarries, and
a bibliography. A very full index is given. The book is
illustrated w-ith several good plates and informatise maps,
and will be invaluable to the architect or engineer who cares
to apply its scientific principles to practice.

G. W. T.

MATHEMATICS.

.4 Xcw Trigonometry for Schools and Colleges. — Bv the

Rev. J. B. Lock. M.A., and J. .M. Child. B.A., B.Sc.

488 pages. ISO illustrations. 8-in. X5T-in.

(Macmillan & Co. Price 6 -.)

In opening a book bearing the names of two experienced
authors, we expected to find much that was sensible and
practically useful. In this we were not disappointed : but a
surprise was in store for us in the arrangement of the subject
matter and also in some of the matter itself. This is a very
■■ live "" book, and a student of fair ability will probably
acquire from it a sound working knowledge of Trigonometry
up to and including de Moivre and Infinite Series and Products
with very little waste of time. In particular we may call
attention to the adniira'ole diagrams, the descriptions of
instruments, the model solutions of triangles with the aid of
logarithms, the proofs .and figures for general formulae, the
treatment of interpolation, and errors of observation. In the
preface, attention is draw n to the fulness of the answers, in
which hints for solutions of the harder questions are given, as

there is no intention of issuing a ke\-. One of these hints is
"■ Use Ptolemy"s Theorem."" Ptolemy is not in the index, but
we ran him to ground on page 383. being familiar with his
haunts. Little omissions of this kind disappear in a second
edition. We cordially commend the book to the attention of
all teachers of mathematics.

MICROSCOPY.

Practical Photo-niicroi>raphy. — By J. E. Baknakd. 322
pages. 10 plates and 7y figures. Si-in. x 5i-iu.

(Edward Arnold. Price 15 - net.)

The usefulness of the microscope and the advantages of
photography being so great and so well recognised, it follows
that photo-micrography must be e<|nally important. The
thanks, therefore, of all those who are about to take up the
work are due to Mr. Barnard for affording them an opportunity
of obtaining an insight into the subject, before beginning opera-
tions, while those who have had to gain their experience for
themselves cannot fail to find some points of interest in
"" Practical Photo-micrography."' The book fulfils the promise
ot its title : for all the information is given clearly, and in such
a way that the directions and advice can easily be followed.
The microscope is briefly considered, then two chapters are
given up to the optical equipment necessary, while an account
of sources of illumination, and descriptions of the various
photo-micrographic cameras are followed by hints as to the
use and manipulation of a microscope, and after the more
purely photographic part of the subject has been considered,
some very useful appendices are added. In his introduction,
Mr. Barnard most properly advises a microscopist who is
anxious to start the work, to acquaint himselt thoroughly with
the processes of ordinary photography ; while, similarly, he urges
the photographer to master the general technicalities of
ordinary microscopic work. The book under consideration
should always be at the elbow of every worker with the
microscope.

TIDES.

Moxly's Theory of the Tides. — By J. F. Rlthven. 103
pages. IS illustrations. 9j-iu. X6-in.

I J. D. Potter. Price 2 -.1

Lieut. Ruthven worked w-ith the late Rev. J. H. S Moxly in
perfecting the theory which the latter put forward with regard
to the tides. The present book is a reprint of four chapters
dealing with the subject, to which have been added several
new ones and a number of quotations from Mr. Moxly's book
which he did not live to rewrite. In the preface Lieut.
Ruthven points out that in the theory there was an error due
to accepting the assumption of the dynamical theorists that
the only w-ay that the tangential component of tidal force could
work was b.\- means of surface currents. Closer examination
con\inced Moxly and Ruthven that it, like the normal
component, produced pressure.

TOPOGRAPHY.

The Evolution of Kingston-iipon-Hull. — By T. Sheppard.
203 pages. 29 illustrations. 9-in. X 5 J-in.

i.\. Brown (."v: Sons. Price 3 6 net.)

.At the request of the Museums and Records Conunittee of
the Hull Corporation. Mr. Thomas Sheppard has elaborated a
presidential address of his to the Hull Literary Club, and has
shown by means of plans, dating from the sixth century to the
present time, the way in which the city of Hull has gradually
come into being. He describes no less than three hundred
and ninety-seven plans, twenty-nine of which are reproduced
to form illustrations. The book should prove most useful
for reference to those interested in the history of Hull. The
remarkable feature of a plan made in the time of Elizabeth,
but evidently copied from one of much earlier date (probably
the middle of the fourteenth century) is the large amount of
space within the city walls which was devoted to gardens.
They practically surroimd the buildings on all but one side.

THE BRITISH MUSEUM (NATURAL HISTORY).

The tide of opinion against the erection of a new seience
museum between the Imperial College and the Natural
History Museum at South Kensington, continues to gather
strength. At present the plot of land bounded on the north
by Imperial Institute Road, on the south by Cromwell Road,
and lying betwefen Queen's Ciate and E.xhibition Road, is
occupied by the two great institutions just mentioned. .At the
back of the Natural History Mnseiun is the Spirit Building,
between it and the Imprri.il College are the temporary
buildings of the Science Museinn. The suggestion is that the
Spirit Building, which cost /, 30.000, shall be pulled down, that
the ground which it occupies and some on each side of it shall
be taken away from the British Museum and form the site of
a new science nniseum.

A glance at the plans issued with the Government white
paper, numbered Cd. 5650, will show at once how each of the
institutions will hamper the others. There will be absolutely
no hope for the Imperial College to spread, the Science
Museum will be in the same predicament and the Natural
History Museum which long ago ought to have been enlarged
will not only lose a part of the land definitely allocated to it.
but even the space which is left, if the Government scheme
does get carried out. will be encroached upon, because it is
proposed to erect a new spirit building along the frontage to
Queen's Gate making it for all practical purposes under
ground, and bringing the roof four feet above the level of the
pavement. The accommodation in the present building is bad
enough, but why should it be proposed that those who work at
the animals themselves, rather than their stuffed hides,
bleached bones, and mummified remains should be condenmed
to carry on their researches in a subterranean excavation.

It is no wonder that the trustees of the British Museum and
lovers of Natural History throughout the British Isles, though
quite as anxious as other scientific peojile that the new uuiseum
should be erecti-d, should wish that some other site might be
found for it.

In the case of private individuals a bargain would have to
be kept, and why should not the Government be expected to
fulfil an arrangement definitely made. There are plenty
of open spaces on the east side of Exhibition Road and. com-
paratively speaking, few houses. No doubt it would be some
hardship for private individuals to have to part with their
dwellings, but surely the development of scientific collections
belonging to the nation is as important as the making of a
railway by private persons, and it is necessary to look before-
hand, not for twenty, but for many hundreds of years.

The original memorial to the President of the Board of
liducafion with regard to the Science Museum was signed by
over one hundred scientific men. mostly chemists, physicists and
astronomers. Dr. Shipley, Master of Christ's College, Cam-
bridge, has already sent in the names of nearly a thousand
eminent men and women, who have signed a memorial express-
ing their emphatic opinion that nothing should be done which
interferes with the development of the Natural History Museum
or which limits the scope of the proposed science museum.

The Entomological Society, knowing that the Insect Depart-
ment of the Natural History Museum greatly needs more
space, has also passed a resolution of a similar character;
the South London Natural History Society and the South-
Eastern Union of Scientific Societies have done the same, as
well as the Essex Field Club, and we have received the
following resolution which has been still more recently passed
at a special Council Meeting of the Selborne Society, which
now numbers nearly three thousand members.

" That the Council of the Selborne Society learns with
grave concern, the declared intention of the Government
to alienate a part of the British Museum I Natural History! in
order to form the site of a new museum, and respectfully
urges upon the authorities that they should seek another site
for the new institution, so that both nuiseums ui.iy have room
for their due expansion."

N()T1CK.S.

THf: Nl-;w EAIK\ FLV.~As we go to press Mr. Fred
Enock telegraphs to say that he has succeeded in breeding a
female of Myinar regcxlis, the male of which he recenth-
discovered, and describes and figures on pages 271 to 273 of
the present number of " Knowi.hdgk."

XRAV APPAR.Vl T S.— The Admiralty has ordered from
Messrs. Newton and Co., of 3, I'leet Street, London, ten sets
of X-Ray apparatus for the new battleships for service afloat,
making thirty complete installations that this firm has recently
supplied to the Royal Na\-y.

INTEREST TABLES.— We ha\e received from Messrs.
Charles and ICdward Layton. Layton's, Simple Interest
Tables (price 5 - net), by .Alexander S. Sellar, which deal
with amounts ranging from £] to i,'lOO,000 for intervals of
one day up to three hundred and sixty- five days and for
intervals of one month up to twelve months.

MICRO-CINEMATOGRAPHV. — Messrs. Pathe Freres
have prepared, under the direction of Dr. J. Comandon, of
Paris, a series of cinematograph films of microscopic objects
for use by lecturers, scientific societies and in schools. At a
recent demonstration arranged for " Knowi.kdgl; " these
films were seen to be of great interest, showing, as they do,
the circulation of the blood. Brownian movements of the
platelets in the plasma, phagocytosis by the white corpuscles
or leucocytes, clearly illustrating the extrusioirand retrocession
of pseudopodia, and, most interesting of all, living trypano-
somes and spirochaetes in the blood of infected animals.
The phenomena of agglutin.-ilion of ihc spirochaetes in the
later stages of rel.ipsing fever and h.ienioh-sis of red corpuscles
were extremely well displ.ayed.

For more popular imrposes films were shown of the life-
history of flu' swallcjw-tail bnlleifly, caterpillars feeding on

wild carrot plants, their mo\ements and the extrusion of their
horn-like scent appendages, pupation, the emergence of the
imago, the drying of the wings, and then the beginning of the
acti\e life of the perfect insect among the flowers. .Another
film showed the development of the Axolotyl within the egg,
its emergence and, subsequently, its preying on tadpoles.
Students who are not aroused to enthusiasm by such exhibi-
tions must indeed be hard to please.

SUMMER FLOWER SHOW AT OLYMPIA. — The
Flower Shows of the Royal Horticultural Society are famous
throughout the world for their excellence and beauty, and they
well deserve the popularity which they enjoy. The Society fosters,
and by its Exhibitions nourishes, the love of plant life in the
hearts of English people, and its direction is sought by an ever-
growing body of people representing all classes of Society.
The increase in the number of Fellows, and the crowds
attending the Flower Shows, are putting a great strain on the
Council and Officials, who are doing all that is possible to do
to meet the demands of the times in horticulture. Therefore,
friends of the Society welcomed the proposal that the
Sunnner Show of this important year should be on a scale of
magnificence and comfort hitherto wholly unprecedented in the
Society's history, and the great Hall, " Olympia," was accord-
ingly engaged for it. The dates fixed are July 4th, 5th and 6th.
Many exhibits will, in themselves, be quite considerable
gardens. .Sunnner being at its height, the exhibits will largely
comprise open-air trees and plants, rock-gardens and water-
gardens.

On July ttli (lie Show uill be open from 12 noon to 10 p.m.;
on July 5tl] fmni 'I ii.ni. In 10 p.m.: and on the 6th from
9 a.m. to () p.m. In order that the public with narrow purses
and little spare time may take advantage of the opportunity
thus offered, the price of admission after 6 o'clock on the first
two days is to be one shilling.

288

Knowledofe.

With uhicli is incorporated Hardwicl<c's Science Gossip, and the Illustrated Scientific News.

A Monthly Record of Science.

Conducted by Wilfred Mark Webb. F.L.S., and E. S. Grew, M..\.

AUGUST, 19 11.

THE TRUE STRUCTURE OE THE DL\TOM

VAE\'E.

B

T. F. S.MITH.

It is not within the scope of this article to enter
into the biological details of Diatoms, the writer
assuming, and rightlv too, he thinks, that thev are
already known to the readers of " KNOWLEDGE."

His purpose is rather to

treat of them as test
objects: of the part they
have already played in the
development of the achro-
matic microscope : of the
part thev still should pla\"
r '^\SSm'\ '" opening up the road

r ■ i ""iv, \ towards further advance-

'<■ ': ; " 1 ment. He also wishes to

state his own \iews of
the structure of the valve,
the nature of which has
given rise to so man\-
discordant opinions.

In Ehrenberg's monu-
mental work, " Die Infu-
sionsthierchen," published
in 1Sj8, diatoms are treated
as animals, in opposition to
almost all the authorities
of that day. This can be
of but little importance to
us now.
how a

led astra\- b\- the follow-
ing up of preconceived
opinions. Of greater in-
terest, so far as diatoms are
concerned, are the superb
coloured drawintrs sriving

save in showing
great mind can be

us a clear insight of the definition of the microscope
then. He describes the various species, some as
smooth, some as striated : yet, on carefullv going
over the corresponding striated forms, under the
microscope, it will be
found that the\' can all lie
resolved b\- an inch objec-
tive of -30 X..\.

\\'hile upon the subject
of comparative capacity,
it may be of interest also
to give an example from
a slightly later date.
One species described and
figured b\' Ehrenberg as
smooth is Xai-iciihr (now
Pleiirosii^iini i liippdCiunpiis.
In 1.S41. a Mr. Harrison.
of Hull, discovered longitu-
dinal striae upon this form,
and sent specimens to the
-Microscopical Society of
London, for confirmation.
.\fter keeping them for
si.x months the\' were re-
turned to him w ith the inti-
mation that the members
could see nothing. A little
later he also discovered
transverse striae on the same
diatom valve, but found
them more difficult to ex-
hibit. These can be easih'
resolved now b\- a half-
inch objective of -50 X..\.

Figure 2.
U nder layer.

Figure 1.
Upper layer.

Two layers of a valve of Plciirosigiiia lUigiiltjtKiii. In each case entirely separated from the other and left sticking to the

Taken with a six inilliinetres objective, by Zeiss, -95 N..'\.,and enlarged twice.

cover glass and to the slip respectively

2S9

290

KNOWLEDGE.

Arc.rsT. 1911.

FiGLRE 3. The outer side of Plcitr(isij>ina
funitusKiii when the valve is sound, x 1 750.

When it \s'as recognised
that e\cr\' increase of aper-
ture in the objective revealed
"markings"' on forms deemed
smooth before, there natur-
ally arose from the students
of diatoms a demand for
more, and still more, light.
It is customar\' with biolo-
gists to sneer at such as
mere '" diatom dotters." yet
nearK' all the optical im-
provements of the microscope
have been due to their claims.
Onlv by the consequent res-
ponse of opticians could the
science of bacteriology have
become possible, which now
plays so important a part in
their (the biologists") o\\ n
laboiu's. From 1824 up to
witliin the last twent\" \ears there has been a
regular progression of the powers of the objective
culminating in the apochromatic oil iiiiincrsion
Unfortunately, at this point we seem to stick
though the cr\- is no less urgent for de\'elopment

The right interpretation of the "' markings "
turned mostlv upon whether they were raised
"beads"" upon the surface, or holes through the
substance of the valve. In the larger discoid and
other forms it was admitted that the so-called
cellules were excavations. Even here, however,
Mr. Slack, in 1873. maintained that the he.\agonal
framework enclosing the cellules was made up of
rows of beads. To the imagination of Mr. Slack,
indeed, diatom structure began, continued and
ended in beads.

The writer also must confess to a f(U"mer belief in
" beads."" In a slide of P. foniiosiiin mounted in
balsam were some isolated ones, even under the

Figure 3 A. The same \ahe as seen in
Figure 3, showing the structure imniedi-
atelv below that seen in Figure 3, X 1750.

widest aperture of an oil immersion. Now. except
one possesses tiie lively imagination of the Irishman,
who explained the making of a cannon by saying
" that they took a big long hole and poured molten
metal around it."" isolated perforations are unthink-
able. One can only explain the puzzle bv assuming
that tile structure around them, mounted in a
mediimi of the same refractive index, was con-
sequenth' invisible.

From analogy, the two or three layers of structure
in the finer valves were merelv assumed. It could
scarcely be otherwise before the ad\-ent of the oil
immersion. R\lands. in an article in Tlie Uiiaiierlv
Journal of Microscopical Science for October 1859.
on ■■ the markings of Diatomaceae,"" savs of P.
angiilatinu : " Individual specimens of this species
are far from uncommon in which the outer
' aerolated " layer is partiallv removed, leaving the
inner laver entire. Isolated portions of the outer
la\ er may he found upon the valve, but I have never

seen them separated, the
force which removes them
being apparentiv only suffi-
cient to break them up into
single ' aerolations"; the term
in this case is unfortunate,
for they are. in fact, hemi-
spherical elevations.""

Figures 1 and 2 prove
that the valves of P. angii-
lafiini can separate entirelv.
It seems strange that to
demonstrate this should be
left to the present writer,
nearly tiftv years after
the discoverv of this
form. The two pictures
will well repay studv with
a single lens,
some five or

magnitymg
six times,

^^^:55?5

i^^i!^::!!"'- •'-'-' -2^

FiGURF. 4. The inner side of Plcurosi^iiia foriiiosiim.
The ordinary appearance of a sound vaKe, X 1750.

August, 1911.

KNOWLEDGE.

291

when it will be seen how
accuratcK- the broken parts
tit into each other. One
layer was on the slip and
the other tight against the
cover glass.

He cannot claim to have
been the first, then, to
broach the subject of a
second layer in the tiner
forms. \et he thinks he
was the first to bring it
within the borders of fact,
b}- definition. The work
presented here, except in
the instances mentioned,
was all done with the two
millimetres apochromatic of
Zeiss, of 1-40 X..\. Not
that such an objective is
necessarv in order to see
the structure figured, nor
even to photograph the
same. It can all be seen
with an ordinary cheap oil
immersion of 1 -30. He has
such a lens, of Swift and
Son, costing onl_\- £5 5s.,
and it is astonishing to find
how nearl)- it works up to
the Zeiss, costing £"20. This
for the comfort of micro-
scopists with only moderate
means — by far the greater
number. Every leading
maker now produces a
similar lens at about the
same price.

The points desired to be
driven home in the present
article are that diatom
structure consists of neither
beads nor perforations, as
commonly understood. The
conventional presentment of
the Pleiirosignia everv micro-
scopist knows. The figures
given here will differ from
it in many particulars, as
one would expect to follow
from everv increase of aper-
ture in the micro-objective.
A dry lens of anv kind will
always produce the same
appearance from every unit
of a particular species : the
same can be said of an oil
immersion when the valves
are mounted in a medium,
but when mounted dry, and
an oil immersion used, it
will be found that thev

-^•^8

FiGUKE 5. The outer side of PUurosigma

formoium, showing ihe structure torn and

opticallv separated from that below, X 1750.

-V

Fini^Kii 6. 1 !. I I 111 Hgute 5,

taken witli a ai\ ^ix iiiiimiitiit;, ien^, by Zeiss;

the upper structure is invisil)le owing to a too great

depth of focus in the lens. X 720

FiGL'Ki: 7. Tlie wiiter's "running down" case, X 1750,
anil further enlargeifto 2500.

differ both visually and in
cur\e. Figures 3, ia and 4,
from two valves of P. formo-
siiiii. will illustrate this fact.
I'igure 3 shows the outer
side of the valve, 3a the
structure immediately under-
neath, and Figure 4 the
inner side from another
valve.

Now the difficult\- attend-
ing upon the working of an
oil immersion under these
conditions, is that the object
to be examined must be in
optical contact with the
cover glass. \\'hen against
the slip, or even a little way
off the cover, the lens is no
longer at its fullest available
aperture, indeed, it is but
little better, if at all. than
a drv glass. The same nia\'
be said when the object has
lUDie than one layer of
structure, no matter how
slightly the\' may be separ-
ated. There is the fatal film
(if air between to prevent
that below being seen at its
best. This is wh\' nothing
will be said here as to a
third, intermediate, structure
in the finer and thinner
diatom valves. Analog}- with
the larger and thicker forms
may seem to point in this
direction, \et it has never
been established by demon-
stration. Dr. \'an Heurck
asserts it in his more recent
work, \et gi\es no figures as
[1 roofs.

It nia\" be asked, \\h\'
not examine the objects
mounted in a medium ?
This, certainlw is hv far
the better waw when thick
enough. On the other hand
with \'er\' thin examples,
upon removing one difficultv.
one of another kind steps
in, equalh' fatal. Though
homogeneous, then. b\'
lessening the angle of refrac-
tion, due to the medium,
the depth of focus of the
objective is increased, with
the result that in such
objects as a Pleumsigma
valve, it pierces through
all the layers, confusing the

292

KNOWLEDGE.

AL'GI'ST. 1911.

image of the whole. No increase of magnifying

power will separate the la^-ers. then, though ont

may know them to be there.

The real cause of failure '^

may be explained in this way.

Suppose a sheet of trans-
parent paper with writing

upon each leaf, differing,

perhaps, in both character and

subject. Clearh'. if in close

contact nothing could he read —

separate the leaves to a proper

distance, when both writing

and meaning become plain.

The PlL'iirosi}>nia valve, mounted

in a medium, is the sheet of

transparent paper with the

leaves together: mounted dr\-,

the same sheet with the lea\'es

well separated. Figures 5 and

6 will illustrate this point,

though taken with different

lenses. Figure 5 exhibits cer-
tain structure, discovered h\-

the writer, upon the outer

side of a valve, P. formosiim.

mounted dr\-, as seen under

an oil immersion. Figure (> is

from the same vah'e, and the

same iwint, taken with Zeiss"

six millimetres aperture of -''5

N..A.., a dr\' lens. The struc-
ture seen in the first }>rint is

here totalh' in\isilile as a recognisable image, though

there are certain indications in some scattered dots.

of which no one could discover the reason if taken

1)\- themselves, without the ke\'. In both instances

the magnification is the same.

Figures 7 and 8 are further exam[)les illustrating

the same point. The
subject is what the
w riter has called his
" ru n n ing dnw ii
case." One minute
diatom vahe had
collided with aimther
and rijiped up the
ilcck. if one ma\ be
allowed to use such
a term. In Figure 7
the torn structure at
J the sides is seen
J hanging in strips: so
shallow is the focus
of the oil immer-
sion with which this
was taken. that there
are no indications
of structure under-
in the microscope the tine
It will be of interest to

note here that the two \al\es [present opposite sides

to the eve. Figure S of the same incident is taken

with the same dry lens as No. 6, but tells no story :

not due to insufficient resolving

» . power, as we shall see in an-

•••:': other print, onl\- that the

■. . ' objective has too deep a focus

to separate the layers, or even

the \alves.

We are in this jiosition.
then : we cannot work with
an oil immersion through suc-
cessi\-e lavers of structure when
there is air between — that is,
not effectively — or separate
tluni opticallv in a medium
when the focus is too deep.
This happens with all the
6[jecies of diatoms given as
examples here, except the last,
and there seems to be only
one other wa\'.

We must examine spread
slides in a dr\' mount, and
note the difference in appear-
ance and curves between the
\al\es : stud\' them separately

remembering that, under

FicuRK S. Tlie saiiR- specimen as s( i n iii
Figure 7, X 1720, taUeii with the same lens
and under the same conditions as l-'igure 6.

Figure 9. The outer side of
PI euros igm cj fonnos urn, showing
" chains " of fibrils giving rise to
the appearances seen in Figure
3, X 1750.

neath, though of coursi'
adjustment would gi\e it.

then.

iin oil immersion, only those
tight against the cover will
give the distinctive image.
Referring back to Figures i
and 4. it will be seen that in
Figure 3 onl\- along the middle
is it in sharp focus, shelving down on the upper side
into shadow. Figure 6, however, shows the distinc-
ti\'e curve of the outside of the valve still better
(though not the distinctive structure) : on that side
it is \'-shai)ed in section. In I'igure 4 of the same
diatniii. the inside, it is found to be flat across, except
m the middle, where
that and the median
line are seen bv the
shadow to be below
t h e g e n e r a 1 1 e \' e 1 .
The same difference
of cur\'e between the
two sides of the \'alve
occurs also in P. an-
giilatiiin. and seems
always to accompany
the same distincti\'e
appearance.

These details may
seem tri\ial. \'et are
necessarx in clear-
ing the wa\' to-
wards getting at the
With rei/ard to the

FiGl'RE 10. A similar specimen
to that seen in Figure 9.

ke\- to the real
outer side of P.

Figure 9 seems to

structure.
ioiDiosiini,
supph' the key to I'igure J.
The structure here is fairly sound, but in some
wa\- has been acted upon to leave it bare. It
appears to consist of a series of chains, as it were,

Al'Gl'ST. 1911.

KNOWLEDGE.

293

iars or fibrils of silex, arranged

formed of short
lengthways on the valve. The\' run in pairs, parallel
each pair having larger and narrower interspaces
between them in regular succession, and so placed
that the larger interspaces are set obliquel}- to the
corresponding interspaces between the other pairs,
both above and below. Figure 10, from another
valve, exhibits the same structure torn, and still more
plainly because the " chains " are more isolated.
Now, in explanation of the figures, his theorv is
this, that what we see in the P!ciii osi^iihi valve, when
sound, is not the structure at all. but simpK' a

same valve mounted in a medium. The valve shown
in Figure 11 has been ruptured, leaving in some parts
the outer layer well separated from the under, in
others normal, ^^'e see, then, at the lower part of
the picture the characteristic structure ; in the middle
it is no longer visible, while at the top it re-appears,
though not so well indicated. Figures 12 and 13
are taken bv the oil immersion from the same spot,
the first with the glass slightly stopped down, the
second with the widest available aperture ; leaving
the image hv itself, in the air as it were.

Now for all practical purposes Figure 12 is the

Figure 11. The outer torn ^.tuutiue

of another valve taken with the same

lens as Figures 6 and S."'

Figure 12. The -..um >[h . uu. n .i^
seen in Figure 11, taUen with a two
millimetres objective of Zeiss, slightly
stopped down. < 1750.

Figure 13. The same specimen as

seen in Figures 11 and 12, taken with

the fullest aperture available.

collection of focal images thrown from the other
layer upon the one nearest the eye, just as a picture
is throv\n from the optical lantern upon a canvas
screen. The fibrils or grating is the real structure,
of which the texture is concealed, even as that of the
canvas screen is by the picture. We shall see more
of this further on.

The next three figures, taken from the outside of
another valve, are given more to illustrate the value
of aperture than to elucidate structure. Figure 11.
photographed by the same drv lens as Nos. 6 and 8.
shows that it was not from want of aperture it failed
to exhibit the right structure. To repeat, it is
simply a matter of possessing too deep a focus to
separate the component la\ers. though a most superb
glass. No dry lens could do it when at the normal
distance apart, nor e\-en an oil immersion, with the

most effective picture, as affording opportunitx' for
comparing the relationship of the two layers ; vet
it is always well not to give the enem\- cause to
blaspheme. When these researches began, the
results were put down b\- some to moisture in
the dry mount, to oblique light, to interference
phenomena ; to everv cause, in fact, except to
a revelation of new structure. Speaking gener-
allv. [lerhaps the most irritating of all criticisms
are those which, if the\' are valid, will not only
deprive one of all claims to be looked upon as
an accurate observer, but also of common sense in
conducting his researches. Naturalh-, in very self-
defence, one was put upon his metal, and. b\'
widening the aperture to the fullest a\'ailable,
produced photographs of which this last print and
others are examples.

( To be cent i lilted., t

Here the outer structure is only seen where it has been left against

the under layer.

cover glass more than the normal distance from

THE FACE OF THE SKY FOR AUGUST.

By \\". SHACKLHTOX, F.K..\.S., .A.K.C.Sc.

The Sun. — On the 1st the Sun rises at 4.24 and sets at
7.4<S ; on the 31st he rises at 5.11 and sets at 6.51. Sun spots
are not very numerous ; small groups are occasionally visible
on the solar disc.

The positions of the Sun's axis, centre of the disc, and
heliographic longitude of the centre are given in the following
table ;—

Venus :

D.ite.

Axis inclined
from N. point.

Centre of Disc
N. of Sun'.s ■
Equator.

Heliogiaphic

Longitude of

Centre of Di.sc.

Aug. 4

11° 52' E

6= 2'

335° 49'

9 ...

13° 46' K

6 ' 2 1 '

269° 42'

,, 14 ■•

15" 34'I'-

('" 37'

203° 36'

,, 19 ..

17= i6'K

5° 51'

137° 31'

„ 24 ...

iS' 49' E

7' '

71" .-6'

,, 29 ...

20° i6'E

7" 9'

5° 23'

Sepi 3 ••

21° 34'i-:

7" '4'

299 20

,. S ...

22= 44'K

7' 15'

233" IS'

The Moon ;

Dale.

Phases.

11.

M.

Aug. I ...

D

First Quarter

1 1

29 p.m.

l<^ ..

0

Full Moon

2

55 a.m.

.. 17 ■

1.1

Last IJuarter

0

1 1 p.m.

,, 24 ..

•

New Moon

4

14 a.m.

.. 31 •■•

J

First Quarter ...

4

21 p.m.

Sepi. 8 .

C

Full Moon

3

57 P »'•

Aug. 5 ...

Apogee

2

24 p.m.

,. 21 ...

Perigee .

10

3t) a ni.

Sept. 2 ...

Apogee

7

18 a.m.

OCCULTATIONS. — The following occultations of the brighter
stars are visible from Greenwich : —

Date

Star's

Name

4J

Disappearance.

Reappearance.

Angle

Angle

Mean

from N.

Mean

from N.

-i

Time.

poinr.

Time,

point.

p.m.

Aug.

iS

i Tauri

5-0

1 I . II
a.m.

95"

11-57

235°

>j

22

X Cancri

59

2.13
p.m.

95°

p.m.

277"

Sept.

I

43 Ophiuch

5-4

7.5S

182"

S.4

191'

Mercury

THE PLANETS.

Date.

Kight Ascension.

Declination.

Ii. m.

Jtil)' 31 ■•

10 14

N 11° 19'

Aug. 10 ...

10 59

5° S'

, , 20 ...

11 27

N 0° 15'

,. 30 ...

1 1 30

S 1= 28'

Sept. 9 ...

II 3

N 2° 14'

Mercury is an evening star setting N. of W. at 8.40 p.m. on
the 1st, and nearly due W. on the 20th at 7.40 p.m. The
planet is at greatest Easterly elongation of 27' 25' on the 13th,
when he sets at 8.7 p.m. The elongation is not a favourable
one on account of the low declination of the planet.

Date.

Right .Ascension.

Declination.

h. ui.

July 31 ...

1 1 2o

N 2° 18'

Aug. 10 ...

11 39

S 1= 32'

20 ..

II 48

4° 34'

., 30 ...

11 45

6° 14'

Sept. 9 ...

II 28

S 5" 53'

'Venus continues to be a very conspicuous object in the
evening sky, looking S. of W. immediately after sunset. The
planet is at "greatest brilliancy" on August 10th. when 0-26
of the disc is illumin.ated and the apparent diameter is 38".

As seen in the telescope the planet appears crescent, like
the new moon, three or four days old, and on account of the
large apparent diameter, the crescent form is easy to see, even
in small telescopes magnifying about ten times.

Venus is a severe test for most telescopes, but observations
are somewhat easier if they are made whilst it is still broad
daylight. On the 1st, the planet is on the meridian at
2.45 p.m. and sets at S.55 p.m. ; on the 20th the planet souths
at 1.57 p.m., and sets at 7.38 p.m. During the past month,
many persons have been able to see Venus as early as 3 p.m.
with the naked eye. but there is little difficulty in picking up
the planet half-an-hnur before sunset. Towards the end of
the month the planet becomes unobservable, as she sets too
.soon after the Sun.

Mars : —

D.ue.

Kight Ascension.

Declination.

July 31 ...
Aug. 10 ...

,, 20 ...

„ 30 ■■■
Sept 9 ..

h. ni.

2 34;

3 2..

3 41

4 0

N 12^' 53'
14° 44'

16" 20'

17° 42'

N 18- 49'

Mars rises in the E.N.E. at 10.45 p.m. on the 1st, and at
9.30 p.m on the 31st. At the beginning of the month the
planet is about 1° South of cr Arietis. and at the end of the
month about 5 ' South of the Pleiades. The apparent diameter
of the disc is only 10", and the planet is not very bright or well
suited for observation in small telescopes.

The summer solstice of the Southern hemisphere of the
planet occurs on August 1st, and since it is the South polar
cap that is visible from the earth, we may e.xpect that the
snow cap will not be very conspicuous when the planet is in
a favourable position for observation at the opposition in
November.

The planet is in quadrature on the ')th.

Jupiter : —

Date.

Right Ascension.

Declination.

h. m.

.luly 31 ...

14 10

S 12° 29'

Aug. 10 ...

14 19

12° so'

,, 20 ...

14 24

13" IS'

,, 30 ...

14 29

13° 44'

Sept. 9 ...

14 3S

S 14° 15'

Jupiter is getting more to the West, but still remains a
conspicuous object in the evening sky, and is available for

294

.\i'GrsT, 1911.

KNOWLEDGE.

295

observation for a few hours after stinset, as he sots W.S.W".
at 9.28 p.m. on the 20th. On account of increased distance
from the earth, the apparent diameter is diminishing, the
equatorial diameter on the 20th being 34". whilst the polar
diameter is 2" -2 smaller.

The Moon appears near the planet on the evenings of
the 1st and 29th.

Only few satellite phenomena are observable on account of
Jupiter appearing in a bright part of the sky; these are as
follows : —

^

^

^

o

V

C

r, P.M.\.
£U H. M.

s.

■y.

S

P.M.'s.

H. M.

&

1 P.-M.V

^ H. M.

Au-

.■ius.

Aug.

I.

Sh. E. Q 14

9

[.

Sh.

I. 8 57

II

111.

Sh. E. 7 ;;

5

11.

Ec. R. 8 35

I 'J

1.

Ec.

R. S .5

iS

1.

Sh. E. 7 ii

"Oc. D." denotes the disappearance of the Satellite behind the disc, and
" Oc. R." its reappearance : " Tr. I." the ingress of a transit across the disc, and
"Tr. E." its egress ; " Sh. I." the ingress of a transit of the shadow across the disc,
and "Sh. E." its egress; 'Ec. D." denotes disappearance of Satellite by Eclipse,
and " Ec. R." its reappearance.

The configurations of the Satellites as seen in an in\erting
telescope, and observing at 8.30 p.m. are as follows : —

Day.

West.

f

Ea

t.

Day.

We-t.

En.st.

I

4

0

;

• l

17

423 •'

2

41

^

23

iS

2413 C

3

4

0

13

'9

432 0

I

4

42 ;>

C''

20

431 0

2

5

43

c

I

• 2

21

432 0

I

6

431

Q

2

22

421 0

3

7

423

C'

I

23

4 0

123

S

421

L'l

3

24

41 0

23

9

0

423

25

241 0

3

lO

c

■i34

26

* 3' 0

4
1

II

2'

0

4

27

24

12

3

e''

14

• 2

28

32 0

H

13

31

.'*;,

24

29

21 0

34

14

14

30

0

;■ 34

15

21

0

.34

31

I 0

234

16

c

1243

The circle (Q) represents Jupiter; O signifies that the
Satellite is on the disc ; • signifies that the Satellite is behind
the disc or in the shadow. The numbers are the numbers of
the Satellites.

S.\TURN : —

Date.

Right Ascension.

Declination.

Aug. 1

.', 16 ..
Sept. I ...

h. 111.
3 10
3 13
3 '4

N I i'' 21'

■ S'- 2S'
N '5" 29'

Saturn rises on the 1st at 11.5 p.m. and on the 31st at
9.15 p.m. ; each week he becomes more favourably placed for
observation. Towards the end of the month the planet may
be observed looking North of East at 10 p.m. a few degrees
above the horizon ; he appears as a bright star shining with a
leaden hue. The telescopic view of the planet is e.xtremely
fine on account of the ring encircling the planet, and a good
view may be obtained in small telescopes of about two inches
aperture, if the object glass is good and the instrument is held
steady. A magnifying power of about fifty is sufficient to
show the ring, but a greater magnification is required to see
the belts on the disc, as they are not so conspicuous as those
on Jupiter. The ring appears well open, the plane of the ring
being inclined to our line of vision at an angle of 22" ; the
southern surface is visible. The diameters of the outer major
and minor axes of the outer ring are 43" and 16" respectively,
whilst the polar diameter of the ball is 17". The planet is

stationary on September 3rd. after which his motion is
retrograde or westerly The planet is in quadrature on the
13th. The Moon appears near the planet on the morning
of the 17th.

Ur.^nus: —

Dale.

Right Ascension.

l->e(:linatii

m.

Aug. I ...
Sept. I ...

li. m. s.
1 q 56 21

iq 51 55

S 21'' 20'
S 21" 32'

I.i"
0"

Uranus though somewhat low down in the sky, is well
placed for observation during the early evening, the planet
being due South on the 15th at 10.21 p.m. He is situated
about 2' S.E. of a Capricorni. Uranus is just perceptible to
the naked eye, but can easily be seen with a pair of opera
glasses. The diameter of the disc is nearly 4", and the colour
is greenish. As seen in large telescopes the planet appears
more luminous at the centre of the disc than at the limb —
somewhat similar to Jupiter and Saturn. The planet has a
fine spectrum containing broad dark bands.

Neptune

—

Date.

Right .\scension.

Declination.

.Aug. I ..
Sept. I ...

h. 111. s.
7 34 2 J
7 3-'< 40

N 21" 6' 2"
N 20° 56' 10"

Neptune does not rise till 3 a.m. on the 1st August and
1 a.m. on September 1st; thus for all practical purposes the
planet is unobservable.

Meteors : —

Date.

Radiant.

R.A. 1 Dec.

.\ug. M-I2, .

h. 111.

1 0

N. 57"

(5reat /V!'-.r«Vi?shower : radiant
moving E.N.E. about i''

.. 13-25.

19 24

X. 60

pel day.
0 Draconids ; blight slow
meteors.

The Perseid shower lasts nearly all the month, the earth
encountering the densest portion of the swarm about the
1 1th ; the radiant then being near v Persei. The meteors are
<|uick with yellowish streaks.

Minima of .sMgol occur on the 7th at 11.40 p.m.. the 10th
at cS.30 p.m., and the 30th at 10.20 p.m. The period is
2"* 20'' 49""., from which data other minima may be calculated.

Telescopic Objects : —

Double St.\rs. — Polaris, mags 2- 1. 9-5 ; separation lS"-6.
The N'isibility of the small star is used as a test for a good
2-inch object glass.

<T Scorpii. R.A. 16''15"': S.25'23': mags. 3-0, 7- 6 : separa-
tion 20" -6.

j- Sagittae, R.A. 19" 45": N. IS' 54'; mags. 5-7, cS.S ;
separation 9"-0; colours, white and blue.

a', a- Capricorni, R.A. 20" li"; S. 12° 50': mags, a' 4-5
a" 3-8 ; naked eye double: separation 373"; very easy with
opera glasses.

7 Delphini, R.A. 20" 42'°; N. 15= 46'; mags. 4-1. 5-0;
separation 10"- 8; very pretty double for small telescopes;
colours, orange and light green.

Nebula, &c. — Dumb Bell nebula in Vulpecula, nearly 4^
due North of 7 Sagittae. Rather faint object in a 3-inch
telescope.

(MSI Cluster in Sagittarius ; large luminous field of small
stars : fine object in a pair of field glasses, .\boiit a degree
E. of the star 4 Sagittarii.

NOTES OF A NATURALIST IN THE
MEDITERRANEAN.

Bv G. P.. HONV.

I PROPOSE in this article to gi\'e a brief outliiu- ijf
bird life noticed w hile on a four-months" cruise round
the Mediterranean : particular attention bein,i; t;i\"en
to those birds which \isit Ent^land as sunnner
migrants. Little - far too little — is known of these
birds in their winter haunts, and as I Hnd that the
dates at which I saw some of them in \ariiius
places differ \er\' considerabh' from thnst,' };i\\n in
most books on the subject, thev ma\" be of interest.

I first saw swallows at Alexandria on March 5th.
(J. E. Harting gives March _'5th as the date of its
re-appearance in Egxpt. " Our Summer Migrants "
page 179). At t^prus the\' were common on March
14th. The\' arrived at Platea (S. Greece) in large
numbers on April 1st, and when I finalh' left, a
fortnight later, they were still there, but I saw no
signs of nesting. One came on board on A]>ril -Ith.
when going up the .\driatic (42" 21' N.. \(>" .id' b:..
wind W'.N.W.). ,\t Malta the\' seemed comm(.)n in
the middle of the island on .Vpril 27th. though
none appeared by \'ak-tta. One came on board on
May 1st i,j7 l.S' N., 10 55' E., wind N.W.i when
going to Gibraltar. At the latter place thev were
common on Mav ()th.

Swifts were comnidU at C\prus on Marth 14th,
and at Gibraltar on Ma\- 5th.

I saw a few House .Martins at W'niceon .\pril 4th.
One joined us when four miles from Malta, on April
19th. and there were quantities of tliem with tlie
swallows at Malta, on .\pril 27th. I did not aetualh
see one at Gibraltar, but 1 expect there nmst ha\e
been some at the beginning of Ma\'.

There were some Sand ^h^rtins at Gibi-altar (jn
January 21st, this being the onK time 1 saw an\-.

Hoopoes were common in Eg\pt at the lu^inning
of March, at Cyprus nn March 14th. and 1 saw one
at Platea on March 2-lrd.

There was one pair of Kinged Pl()\ersat Platea for
abniit a week at the end nt March, then the\' seemed
to go.

Turtle Do\es were numerous at .Mexandria (in
.March Jrd. and some of them seemed to be paired
off by that date. One came on board nn April
16th (.56^ 58' N.. 17' 50' E.. wintl \.). when going
from Platea to Malta. .\ pair boarded us on April
23rd, when about eight miles S.W. of Malta (wind
N.E. b}- E.) One joined us on Ma\- 1st (.57" IN'
N., 10° 55' E.) when going from Malta to Gibraltar
(wind X.W.).

Blackcaps and Whitethroats seemed common at
Gibraltar on January 21st. At .Malta the j)lace was
crowded with these and Wood ^^'arbI(■I■s. nn .\pril
25th. Blackcaps were again at Gil)raltar cm Ma\ oth.

Pied Flycatchers and the allied species Miiscicdpa

cilhicoHis (the latter has a complete ring of white
round its neck) were common at Malta on Aprd 25th.

A Grey-headed Yellow \\'agtail joined us on
.Vjiril 2.5rd. when about eight miles S.W. ot Malta,
but the main flocks arrived at Malta on April 25th.
as did also the Meadow Pipits iwind W.N.W.t .\
Golden ()riolewas caught at Malta on .\pril 2.Sth.
I ,i;i\e the last facts on the authorit)' of the bird
catchers at Malta ; these men had cages full of the
birds mentioned and sold large numbers for a few-
pence each.

I also saw Meadow Pipits at .Mexandria. on
Man h .Jrd. and on the same (la\- I saw numbers of
Spotted Fl\-catchers.

Black Redstarts were couiukju at Gibraltar, on
January 21st. and at Platea. on March 2r)th.

Of course the dates gi\'en above do not refer to the
dates of arrival (excejjt where so stated), but only to
those on which I hrst saw the birds at such and such
a place.

Amongst other int(.-restin,L; liirds seen I may
mention a pair of buff-backed Herons, which joined
us when going from Platea to Malta, on \\n\\ Kjth,
TIk ir was a strong w ind from the North at the time :
till' liuils seemed \er\- tired and looked as though
the\- wished to perch, but e\ery time they got far
enough up to windward the\- iell back and had to
beat Uj) again.

I never saw Blackbirtls anxwhere but at Gibral-
tar. Here thev had a different note of alarm from
the Itirds in England.

It is rather remarkable that whereas when we
\isited Malta in .\\)r\\ it was full of birds, at the end
of l'"ehiiiar\ I do not think I sa\\ any birds except
Sparrows, which b\ -the-bye are slightl\- different
from English examples, being slighter and altogether
more " gentlemanh' '" looking.

I'kicks of Ravens were more or less tame in
Cyprus, and when feeding on garbage would allow
one to approach them much nearer than would
r( loks in Englanci.

The Hocks of Kites over Cairo are really wonder-
ful. One dav I counted sixty-hve birds on the wing
at once : a few may haxe been hooded crows (for at a
great height it is hard to distinguish between them)
but the majority were certainl}- Kites. M Platea I
watched with some interest a pair of Common
Buzzards. I found their nest on March 21st, when
it had four eggs : the\- were not hatched when we
left on .April 13th.

Granada was crowded with Nightingales on March
10th. The people told me that they would all leave
in a month's time, but I think that this opinion
IS onl\- held because the birds stop singing.

296

THE NEW EAIRY FLY.

THE DISCOVERY OF THE FEMALE OF
MYMAR REG A LIS.

Bv FRED KNOCK. l'.i:.S.. F.L.S., F.R.M.S.

In the course of mv investigations into tlie life-
histories of the British Mymaridae I have found it to
be of the utmost importance and help to note the
exact locality, not onl\- of the ground, hut the actual
plant on which I have made a particular capture. I
did so on June jrd and Sth, bringing awav some of
the stem and leaves and placing them in a special
breeding box. I scarceh- need to say how frequently
I scanned these
stems with my
magnifier in the
hope of finding the
roval partner of
mx new Mymar.*
Day after day
passed, without
anvthing but tiny
midges emerging.
The longest day
passed after a
boisterous south-
AV e s t \N' i n d —
follo\N'ed by cooler
breezes — then on
the 22nd. the
Coronation da\- of

Kin.£

George

V.

and Queen Mary.
when the grand
procession had
passed, down
came the long-
wished -for rain.
Each day brought
more rain, and
Fairy Flies appre-
ciate a gentle
shower and moist
atmosphere. \\ hich
softens the hard stems through w hich the imprisoned
Mymar has to bite its way.

On June 27th, I carefully examined all
m}- breeding boxes, finding a number of various
species combing their antennae and preening
their wings. .\t last I came to my special box,
containing stems from Burnham Beeches, and
there I saw a Mvmar, which, when corked up in a

tube, I tremblingly examined with mv magnifier,
and smiled with great happiness, for it was the
ro\al consort — the female Mymar recalls with its
under-wings arching down in a graceful curve, the
tip terminating in a few long hairs.

The general colour of the body and legs is
ferruginous, with a slight darkening on the dorsal
area. The antennae are very delicate and as long

as the whole
insect, the first
and second joint
ferruginous, the
third and fourth
(the latter very
long) dark brown,
the fifth lighter,
and the sixth,
se \- e II t h and
eigh t h almost
\ell()\\. while the
ninth (the club)
is dark brow n.

After making a
detailed descrip-
tion of it, I com-
mitted it to the
killing phial, and
it is now success-
fully mounted in
that most beau-
tiful of all media
— Canada balsam.
The capture of
this most striking
species, which is
altogether new to
the scientific
world, proves that
there are yet many
there were more
of our Parasitic

Figure 1.
Mymar rcgalis. magnified 30 diameters.

good things to be taken if only
workers in the fascinating study
Hymenoptera.

During the past thirt\'-five years the writer has
captured hundreds of specimens, composing eight
new genera, running up and down the panes of glass
of a small conservatory, as well as on those of the
house.

[In " Knowledge " for July. 1911 (Volume XXXI\'. page 271), Mr. Enock described a new species of Fairy Fly under the
name of Mymar rcgalis from a specimen of the male which he obtained in Burnham Beeches. — Eds.]

297

SOME NOTES OX ACTINOSPHAERIUM EICHORXII.

By EDMOXD JOHN HUNT.

The study of the minute organisms inhabiting pond
and stream has ever proved a fascinating field of
research to the student of that world of teeming life
which the microscope has been instrumental in
bringing within the range of man's vision.

Among the numerous forms of surpassing beauty
shown b\- the microscope to be contained in a little
water obtained from the weed-covered surface of
some sequestered pool. few. perhaps, can surpass in
general interest that veritable giant among its
compeers — the Actinospluieriiini eicJinniii : and the
following brief notes, the result of close observation
and studv of that interesting organism, ma\- possibly
pro\e of some interest to many students of pond life.

Under the generic name, Actinophrys, .A.ctino-
sphaerium was formerlv ranked with the smaller
Heliozoon — Actinophrys sol — but is now dis-
tinguished as Actiiiosphacriiiin cichoniii.

Regarded as a microscopic organism, the .4l///k)-
spliaeriiitn is found to be of comparati\ely large
dimensions ; for, while the size of Acfiiiophiys sol

varies from

to

of an inch, that of

Acfiiiosp/iacriiini is about yjjn of an inch. Indeed,
so relativelv large is its size that, on holding to the
light a small aquarium containing specimens of the
organism, it ma\- frequenth' be detected with the
naked e\e, appearing as a minute spherical speck of
a greyish colour, either King in the debris at the
bottom of the bowl, or suspended among the threads
of confervae which may be floating in the water.

Although holding a lowh' position in the scale of
life, the structure of the Actiiiosphaeriitm yet shows
some advance on that of the Amoeba ; the lobose
extensions characteristic of the latter organism being
in the case of Actiiiospliacriiini differentiated into
thin ray-like pseudopodia, which, although cajiable
under certain conditions of being w ithdrawn w ithin
the body substance, are \'et, as a rule, more often
extended for the purposes of locomotion and the
capture of food.

Placed on the stage of the microscope, under a lens
of low power, the Actinosphaerium is seen, like the
Amoeba, to consist of two layers, namelv, an outer
layer or ectoplasm, which is of a comparatively firm
consistencv, and an inner layer or endoplasm.
Viewed under a lens of fairly high power, the
ectoplasm is seen to be composed of a vacuolated
substance, some of the vacuoles being of large size.

In appearance the ectoplasm somewhat resembles
the meshes of a net, the lines representing the meshes
containing minute dark coloured granules which are
in constant motion, while the interspaces appear, as
a rule, to be clear and colourless.

Treated with an alkaline reagent these vacuoles
may be seen to coalesce.

In the endoplasm the vacuoles are of smaller size

than in the ectoplasm : globules and granules of
various kinds are present, and embedded in the
protoplasmic mass may be seen numerous spherical
bodies, each containing a dark-coloured substance.
These bodies represent the nuclei with the accom-
panying nucleoli, and in some cases the\' appear to
be present in \er\' considerable numbers. .As
previoush' mentioned, the ra\-like pseudopodia.
radiating from the bod\' in all directions, show a
considerable advance in structure on those of the
Amoeba, being apparentl\' formed bv an extension of
the ectoplasm, while running down the centre of
each pseudopodium is a structure having the apjaear-
ance of a minute rod. These rods extend into the
endoplasm. and in manv cases appear to abut on the
nuclei. Whatever may be the nature of the sub-
stance of which these rods are formed, and it does
not seem to be at all clearl\- understood, there can
be no doubt as to their being characterised bv a
remarkable condition of toughness and elasticitv.

It sometimes happens that a free-swimming
infusorian has the misfortune to be caught on the
extreme end of one of the long pseudopodia, and, in
its violent struggles to free itself, will bend the
pseudopodium until the latter assumes the shape of
a bent bow. ha\ing much the appearance of a fishing
rod as seen in the hands of an angler playing a large
fish. In such a case the strain must be enormous,
and should the infusorian succeed in making its
escape, a contingency which not unfrequentlv
happens, the pseudopodium is seen to spring back
at once to its original position, apparentlv quite
uninjured by the severe struggle.

Under certain conditions, as, for instance, when
transferred from one glass cell to another, the
Actinosphaerium frecjuentlv completely withdraws its
pseudopodia within the body substance, but the\- are
soon again extended on the organism being left for a
short time undisturbed.

The pseudo[)odia are used for the purpose of
capturing food, and probably also as a means of
locomotion.

In all the specimens under observation two and
sometimes three contractile vacuoles were always
present.

These vacuoles expand very slowly, and when
fully dilated project beyond the surface of the body.
The outer walls then contract, presumably casting
out the fluid contents, although no passage through
which these latter could escape can be detected.

In "The Microscope and its Revelations" Dr.
Carpenter, in speaking of the contractile vesicle
as seen in Actinophrys sol, says that " the cavity of
this sacculus is not closed externally, but communi-
cates with the surrounding medium, not. however, by
any distinct and permanent orifice, the membraniform

298

Alir,iiST. 1911.

KNOWLEDGE.

299

Willi gHin,^
closinj;

\\a\- when the vesicle contracts, and tlun
This alternating action seems to
serve a respiratory purjiose.
the water thus taken in and
expelled being distributed
- through a ss'stem of channels
and vacuoles excavated in
the substance of the body,
some of the vacuoles which

vacuoles
are nearest the surface being

Figure 1.

observed to undergo disten
tion when the vesicle con
tracts, and to empty themselves gradually
as it refills."

When injured in an\- wa\' the recupera-
tive power of the Actinosp/uicriiiiii appears
to be very great. It sometimes happened
that on transferring a specimen from the
aquarium to the glass cell for purposes of
examination the organism would sustain
more or less damage, and on one occa-
sion so great was the injury that a con-
siderable portion of the endoplasm was
pressed out of the bod\- and could be
seen floating in the surrounding medium,
while the pseudopodia were all more or
less destroyed. Despite, however, these
apparently hopeless injuries, the work of
repair was at once commenced and so
quicklv effected that in a comparativeh'
short space of time the Actiiwspliacriimi
had made good the damage sustained,
and with extended pseudopodia was ready
to seize any prev that might happen to
cross its path.

It is generalh- stated that w hen unsuit-
able conditions arise, the Actiuosphacriuiii
becomes encvsted, remaining in this con-
dition until the provision of a more favour-
able environment enables the organism to
resume its normal state of existence.

No doubt this is sometimes the case,
\et close observation points to the fact
that under unsuitable conditions death
often supervenes, while encystment more
generally takes place prior to reproduction
by division.

Previous to death the endo[ilasm becomes greatl\-
contracted and numbers of the pseudopodia appear
to fuse, a process which gives them the appearance
of broad spikes protruding from the body. After
remaining in this condition for some time the
contents of the body break through the containing
membrane at some one point, filling the surrounding
water with globules of various sizes.

A large portion of the life of the Acfinosp/uicriiiiii
appears to be occupied with the capture of food, the
choice ranging from small particles of vegetable
matter to free-swimming infusorians, and even such
comparatively highly organised and powerful
creatures as the various species of Entomostraca.
Of these latter the smaller species are easily

captured, eaten, and digested, but with the larger
species the Acfiiiospluieriiiiii does not appear
powerful enough to deal.

The organism appeared also quite unable to cope
w ith some Paramecia when placed in the same cell ;
the infusorians by a sudden twist of the body
speedily freeing themselves from the clutches of the
pseudopodia, which latter were invariably much
damaged, and not unfn-iiucntly completely torn off
in the struggle.

Periods occur when the Actinosphacrium rests

fr

the

Figure 2.

Figure 3.

Figure 4.

abour involved in securing a sufficient food
supplv, and it is of great interest to note
that during these intervals free-swimming
infusorians appear able to come into
contact with the pseudopodia with no
danger ensuing to themselves.

When food-taking, the method adopted
bv the Actinoftpliaeriiim for capturing its
prey is of peculiar interest.

Should an infusorian or other organism
chance to come into contact with one of
the pseudopodia, it is at once captured
and firmly held ; the capture being
generallv attributed to the action of a
coating of some viscous substance. If
this be really the correct solution, it
seems clear that this substance can be
secreted only during such time as the
Actiiiosphacriiiiu is engaged in food-taking;
for, as previously mentioned, there cer-
tainlv occur periods when similar organ-
isms are able to come into contact with
the pseudopodia with perfect impunity.

In the event of the captured organism
proving to be of small size, it glides up
the pseudopodium until, on reaching the
bod}-, a portion of the ectoplasm appears,
as it were, to be rolled back, thus forming
a kind of mouth within which the strug-
gling victim is speedih" engulfed.

When, however, an Entomostracan
or other comparativeh' large organism
happens to be caught, the mode of
procedure adopted
bv the Acfiiio-
sphdcriiiii! appears

to be of a different character.

In such a case the neigh-
bouring pseudopodia are bent

over to assist in holding the

captured prey, while, by a

process of contraction, the

latter is slowly conveyed

towards the body of the

Actiiiosphaeriiim. After being

engulfed, the Entomostracan

or other organism is seen to

be enclosed in a vacuole

which soon commences a

slow circulation round the

body, a considerable time. Figure 5.

300

KNOWLEDGE.

Al'GUST. 1911.

however, elapsing befc

tlK

strut:

of the

captured animal finallv cease. In the case of an
Entomostracan. the process of digestion being
completed, the hard indigestible shell is gradually
worked along to the surface of the body and
ejected, a depression appearing in the ectoplasm
at the place where the hard substance passed out
into the surrounding medium.

The process of digestion is of a sonuw hat tardy
nature : in one case an interval of nearly t\\ enty-
four hours elapsed from the time an Entomostracan
was engulfed to the time the emjitx' shell was
ex[K'lled from the body.

Waste matter is occasionally ejected from the bod\'
of the Acfitiospliacriiiiii. Sometimes this waste
material is enclosed in a bladder-like x'acuole which,
on leaving the bod\-, appears to glide along the
pseudopodia, finallv floating off into the surrounding
water where it gradually collapses, the contents
being dissipated. Occasionall\' these bladders are
suddenh- ruptured and the contents expelled with
some considerable amount of \-iolence.

Another curious phenomenon in tlie life historv of
the Act inospliae rill III ma\- occasionalh' be witnessed
w hen two of these organisms slow 1\- approach one
another, cross their respective pseudopodia. and thus
united, glide slowly through the water. In a short
time the body substance of the tw(.) organisms may
also be seen to come into contact, ajjpearing as in
Figure 1. .\fter the lapse of about a quarter of an
hour, the two bodies apparently become completely
fused, as shown in Figure 2. their respecti\'e pseudo-
podia remaining, however, quite distinct, together
with the two centres from which they radiate, w bile
there appears to be a dividing line between the two
endoplasms. This dividing line soon, however,
disappears, the two endoplasms merge into one,
while all the pseudopodia are now seen to radiate
from a common centre, and in the course of about
an hour the two bodies have become as one, as shown
in Figure 3. The phenomena of cytotrop\-, or the
mutual attraction of two or more cells, are in all pro-
bability closely connected with conjugation, and
cytotropy, leading first to contiguity, may result in
plastogomy, or the fusion of plasms. The proto-
jilasm, however, must be in the proper plastic
condition for such a union, and some of the Heliozoa
are apparenth" alwa^'S in this condition and contact
results in fusion. In many cases, however, plasto-
gomy leads to nothing further, and no nuclear
fusion takes place.

Occasionalh' two large Actiiiospliaeriu will unite
and form a body as shown in Fig. 4, large
spherical vacuoles being visible in the bod\- substance.
.\fter remaining in this condition for some hours the
two bodies gradually round off into the form of a
perfect sphere, .\gain, it sometimes happens that the
two bodies, after remaining fused for some hours,
will separate, then appearing to ln' in the same

condition as before the fusion occurred. In other
cases, the two Actiiuisplujcria are seen to be united
by a narrow band of protoplasm as shown in Fig. 5.
In appearance this connecting band resembles an
elongated pseudopodium. the only difference being
that it is somewhat thicker, while in the centre thereof
is an expansion having all the appearance of a very
small Acfiiiospluicriiiiii. In a short time the band
connecting the organisms A and B (Fig. 5) parts,
leaving B, now rounded off into a perfect sphere,
still attached to C. Soon afterwards the band
connecting B and C is also severed, leaving B and C
floating in the water as separate organisms.

It is [Possible tluit the abo\e-mentioned phenomena
form cases of plastogom\', and are not followed by
fusion of the nuclei as in true cases of conjugation,
although the latter has apparently been clearly
established in ActiiKi/^lirys sal.

The Acfiiiospluicriiiin reproduces its kind by
means of binar\' subdivision, which is repeatedh'
performed under the protection of a cyst.

In such a case the Actinosphaeriiiiit withdraws
most of its pseudopodia. while others coalesce and
protrude from the hod\' in the form of broadish
spikes. The ectoplasm appears to be very clear and
the vacuoles of large si^^e. while the endoplasm is dark
and opaque, and the w hole bod\" shows a considerable
decrease in size. In this condition it sinks to the
bottom of the (■(.•11 an(_l. after an interval of some
twelve hours, a kind of gelatinous substance
commences to form around it. On touching this
substance with the point of a very fine needle it is
found to be of a slimw sticky nature.

The gelatinous covering graduall\- increases in
firmness, and under the protection thereof the body
substance of the Acfiiiospliaeriinu undergoes a process
of division until from ten to thirteen different parts
can be detected.

Each separate part is of a dark colour and is
surrounded b\- an outer layer of some substance of a
clear transparent nature. These \'arious parts repre-
sent the \oung Actiiiosphaeria, which, after remaining
in this condition for varying lengths of time, finally
break through the cyst and soon acquire the likeness
of the parent form. It has been stated that the
Acfiiiosphaeriiiin reproduces itself by simple fission,
the cell slowly separating into two parts, and it is
further said that, should these organisms be kept for
some time without food and then be provided with a
superabundance thereof in the shape of Stentors,
they will multiply rapidly by division.

However this may be, close observation of these
organisms has never shown the Actiiiospliaeriiini to
undergo di\ision save under the protection of a cyst,
while, furthermore, the introduction of Stentors into
the glass cell invariabh- caused the Actiiiosphaeria
under observation therein to withdraw their pseudo-
podia, being apparently quite unable to cope with
the powerful Stentors,

THE COMMON SANDPIPER (Totauus hypolaicus).

Illitstratctl from Pliotoi^raplis

Bv E. W. TAYLOR.

A i iiiriiiiiiii Sandpiper on her iicst.

1 lie eKKs <il lli<- L.'iiiiiinn S.iiidplprr

Young Sandpipers hatching.

Young Sandpipers showing their protective colouring.

301

FAMILY HAXDWRITIXG.

Bv K. H. chaxi)li:k.

The likeness which exists between the writing
of various members of the same family is often
exceedingly strong, and for the purpose of a just
comparison it is necessarv- to have the same words
\\ ritten b\' related people. The names and addresses
on envelopes are \-ery useful, though as these are

b. Brother.

Figure 1.

The words are joined in both cases and there is a great
similarity in style.

loJQ^

l^V u;valc<5

C^ o^ru^cU' ^ ^'

may show itself b\" the colour of the ej^es (a very
frequent one), shape of the nose, general outline of
face, or eccentricitv of manner, but more often it is
the tout ensemble (something that we could not put
into words and define accuratel\>. which causes old
friends of parents to exclaim, when meeting the
children after some \ears, — "Isn't he like his father?"
or, '" He is just like his father as a boy."

This brings us to another point of agreement
between handw riting and ourselves, viz.. likeness at
corresponding ages. It would be absurd to expect
a grandfather of seventv to write like his son of
forty-five, or his grandson of twenty, but there may
be made a just comparison between the grandfather's
writing at middle-age and his son's at the present
time, or between that of the son and grandson
at corresponding ages.

^ZiuyU^' ^^<y^'^

Yf^K^-7

b. Brother.

a. Sister.

I'iGfKi: 2.

The style ol this handwriting should be compared with that of the three brothers, seen in Figure 3.

written carefully when they are unknown, it would
be better to lia\e a few familiar words written
without any hesitation. The family likeness in
the illustrations which we give is apparent to
an\-one, and if we were not intimately ac(iuainted
with the handwriting of all of these it would
be eas\' in some instances to mistake one for
the other. Take higure 3 ia and /)i, two
brothers ; Figure 4 (a and b). father and son : I-'igure 6
{ii and b). two brothers: Figure 7. two sisters or
Figure 9 (n and /)) two brothers, which are hardh"
distinguishable one from the other ; and even where
the likeness does not approach almost to identitv
(as in the instances just given) there is a \-er\-
strong famil}' likeness in formation and st\le — take
Figure 2, showing brother and sister w here the st\Ie
is pronounced and very similar, or Figure 3. Figure 5
shows the round handwriting of a father and son
(if it were possible to show the signatures the like-
ness would be very much stronger) and Figure 9,
which shows a strong likeness in the angularit\' (or
acuteness) of the handwriting of three brothers.

Familv likeness in handwriting follows the same
general principles as family likeness among human
beings, which may be defined as an accumulation of
indescribabh' faint suggestions of similarit\' rather

Another point of agreement (a sub-species of
"family likeness") is what ma\- be called "peculi-
arities," and the father who has a stvle of

^TAciAi

a. Brother.

UlA.

<Q^^U^..M^

b. Brotlier.

%.

m^

-tn^^

^n

c. Brother.
FiGURK 3.
a and h are hardly distinguishable.

handwriting that shows these peculiarities will
frequently bequeath them, more or less unaltered,
to his son.

thanany strong identity; for instance, a familylikeness Bearing in mind these suggestions, that is, the

302

August, 1911.

KNOWLEDGE.

.503

/h-Tc

influence of age on hand-
writing and the meaning
of the expressions " famiK
Ukeness "" and "peculi-
aritv," we may proceed to
study some more examples.

Peculiarities are astonishingly e.\-
hihited in some of these illustrations.
Take Figure 1, which shows the rapid
writer's trick of running the words
together; the peculiar formation of the
■■ r " of "dear," and the " Ch " of
"Chandler." Figure 4 shows dr) father,
aged ahout seventw and two
sons, both of whom have inheri-
ted a peculiar capital " D,"
" H ■" and '' K." In Figure 7 the ^^
w riting is not a characteristic ~f^-*
one, but the " the "' in each
case is identical and the '■e'"s
are blind. But Figure 8 illus-
trates these features better : it
is the handwriting of a father
and son. and superficially one
would say there was no likeness between them :
but notice the capital " (" "s and " 15 '"s. the flourish
at the end of " Chandler " in the father (if) has
liecome a detached

l-.ithL'r.

te^C^^

b. Snil.

/J^nt

handwriting than boys at
. a corresponding age, which
writing does not change so
very much through life,
whereas a bo\- usually does
not begin to show his
characteristic and permanent hand-
writing until some \ears after he has
left school.

There is a common st\'le of girl's
handwriting (something like Figure 2
(<r), but rounder and less characteristic)

knc

.^^^y--^ ,t^^^

Son.

iMi.rKi. 4.

The capital Iftters " D," " H " and " K " are

pecnliar. and there is a strong Ukeness between

a and /).

dash in the son (b) \
they both put "etc."
or its ecjnivaleiit after
" Builder " (whose
" e " is a Greek one
in both cases) and
they are liable to stop
the [len at the same places
— in the word "Chandler"
the\' both leave a space
after " h " and " n," in
" I>uilder " after " 1." and
in " Belvedere" after "%■"
and " e." This last in-
stance is ver\' curious : for
there is no apparent
reason for leaving the " e '

(^^^^/i&Zif^^ti^^^^

I'.itl

>2^

/). Son

I'na'KE 5.
The roundness of the writing in both cases is striking

in the middle of the wore

all by itself when the four letters both preceding and
following it are joined together.

I have been unable to collect such striking sjieci-
mens of the hand- /

writing of women as //^^^^

IS the " High School writing."
I suppose, because High School
girls write it, and if this does
not alter later it shows that
women write less character-
isticalh- than men : anyway, I
have met with " High School
girl's writing " in a woman of
thirtv, and I believe it would
be rare to find a man whose
handwriting had not altered
between sixteen and thirt\'.
These remarks appl\- to women who write a few
famiK- letters a week, and not to women in business,
who niight write as strong or as pronoimced a

st\de of handwriting
as any man.

In F'igure 2, there
is not much to choose
between brother and
sister, and Figure 7
seems more or less
weak and rambling,
but this \er\- weakness is
alike in both.

A curious case is pre-
st'uted by Figure 4 {a)
which shows strong hand-
w riting for a man of
seventy, and whose pecu-
liarities are exhibited in
(h i.\: c) two of his sons,
but his eldest son. h'igure 5 \a) . writes totally
unlike the rest of the family, and yet he. Figure
5 Uf), has bequeathed his own handwriting to his
o\\ n eldest son. Figure 5 (/;

Jt^ a/'^r:^1^^.-i::>

^l^^cZ/.

<<^

. l-lii.thir.

That handwriting
is an acquired

/X. ^-/..

'7

^

7^. — "'

h. Krother.

j^ »--»-

of men, and it mas'

[irobably be taken as

a general _^<^

rule that

women do

not write

such char-

acte ristic

"hands" as

men (the vast majority write very much less than pear that the

besides, I fancv most girls on leaving school inherit the power of writm

Figure 6.
The two handwritings arc almost indistinguishable.

character there can
hardlv be any doubt.
We only
inherit the
p o \\ e r of
learning
to write,

mem ners

men)

write a better u.c. more formed and permanent

the
There

are, nevertheless.

though it

would ap-

a famih' ma\-

in a particidar

the questions

304

KNOWLEDGE.

August, 1911.

fi^'h^nc-, ^ '^ *'>— >A^

written mv name more than two or three times
ill his hfe. whilst the producer of /) has li\ed in
London for the past twenty-five years and has
wi'itten m\- name several thousand times.

a. Sister.

In the case of Figure j

A-c\y^

h. tMSttT.

Figure 7.

The word '" the " should be specially noticed and the hand-
writing in these two instances is also nearly identical.

of influence and imitation to be
considered.

Charles Darwin, long ago. recog-
nised that handwriting was inherited,
and this idea may be found scat-
tered through scientific literature
as an axiom for the past fifty years,
but. so far as I know, it has not
been illustrated before.

A friend, to wh<jm I mentioned
these enquiries, informed me that
he had frequently noticed that the
juniors in an office came to write
more like their chiefs as time went
on, and I have since heard the same state-
ment made by other people who had no
interest in the subject, but as I am unable
to produce any specimens it would not be
well to rel\- upon this, which appears to be
a clear case of environment and imitation
(conscious or unconscious).

On the other hand, the writer of I'igure
1 (7 lives in Wales and has probably not

17. Brother.

b. Brother.

the two brothers a
and (.■ were at school together, but /) is fifteen
^■ears older and was educated entirely differently.
yet the youngest brother a writes more like his
eldest brother h than the middle one c.

Belonging to the famih' ot I'igure 4 there are two
other brothers (besides Figure 5 mentioned above)
whose writing is quite unlike these specimens and it

<^^^ ^^y^^^

If. 1 athei-.

^^di^-^^ <i^^^^<, —

The

and

U<

c. Brother.

Figure 9.
All these specimens are angular, while a and /) are very much alike.

^/%^^a^^

h. Son.
Figure 8.

capital ""Cs" and " B"s " should be examined
the spaces left between some of the letters are
also notew'orthy.

seems more difficult to account for such
difterences than for many similarities.

These illustrations are sufficient to
prove that handwriting is hereditary
(sometimes to a remarkable extent), and
in .some instances environment can ha\'e
had verv little to do with it, but in many
cases we know so little of the infiiiences
brought to bear upon such a flexible growth
as handwriting, that it is quite possible to
underestimate the effects of en\-ironment.

A UNIQUE SUNDIAL.

Bv O. PAUL MONCKTOX.

SixcE the davs of Ahab, King of Israel, the art of
dialHng has been practised by kings and princes as
well as h\ less favoured folk : but although many
quaint dials are known to be in existence, the writer
quite recently came across a specimen which must
be unique in the annals of horology.

This dial, of which a full-size
drawing will be seen in Figure
1, 2, and 3, consists of a short
c\lindrical body, made of wood
two-and-a-half inches long by

Figure 1

The cylinder. The

dotted Hue shows

the hollowed

recess.

Figure 2.

The cylinder cap with

the gnomon lying in

the saw cut.

plate is underneath and projects at right angles to
the c\linder. The long edge of the gnomon, resting
on the flat top of the c\linder, is thus compelled to
assume a horizontal position w hen the cap is pressed
home as in Figure 3.

When not in use, the gnomon is twisted through
a right angle and rests in the saw cut. Thus the
dial can easily be carried in the pocket.

The vertical lines drawn down the cylinder corres-
pond to the months of the year, the letters of the
alphabet indicating the different months — D. for
December, and so on.

Referring now to the developed cylindri-
cal surface, in Figure 4, the vertical lines
correspond to the lines on the cylinder, the
letters at the bottoms to the months in the
year, and the point marks on certain of
the verticals, to calculated inter-
vals measuring from the top of the
c\ linder. These intervals depend
in length on the latitude of the
place for which the sundial is
designed, the time of day, and the
particular length of gnomon taken — in this
case three-quarters of an inch.

The vertical numbers, one, two, three,
four, and so on, refer to the hours of the
da\'. The cross-curves, drawn in red ink
on the original cylinder, join up corres-
ponding points on different verticals. -As

^B

\

arrow indicates the
pivot on which it turns,
the lower arrow shows
the direction of the
shadow vertically down
the cvlinder.

three-quarters of an inch in diameter,
surmounted b\- a wooden conical cap
one-and-a-half inches long b}- three-
quarters of an inch in diameter at its 1 igure 3.
thickest section. This cap fits into the This shows the gnomon
top of the c^•linder. the latter being in position. The upper
made hollow for the [)urpose.

The whole of the dial-cap and
cylinder, with the e.xception of the
gnomon, was made of a light vellow
wood. Vertical lines are scribed at
intervals down the whol'_ length of
the cylinder ; Figure 4 show s the development of
these lines as if the surface of the cylinder were
laid flat on a piece of paper.

The shank CD of the cap fits into the hollow .\B
down the centre of the cslinder. .\ saw cut has
been made half wa\' up the cap as shown in Figure
2 and a piece of tin-plate, F"igure 5, inserted
in the slot. This piece of plate constitutes the
gnomon of the dial, and is pivoted at one end
by a nail passing through one corner as indicated.
The hole is drilled in such a position that, w hen the
gnomon is in use, the long straight side of the tin-

FlGURE 4.
The development of the cylinder.

these points are mere indentations in the wood, made
with some sharp instrument, they would quickly
become obliterated by dirt or usage unless some
distinctive marking were used.

305

306

KNOWLEDGE.

August, 1911.

In order to appreciate the action of the dial,
consider the position of the earth with regard to the
sun at different periods of the year. In the height of
summer, when the sun is high over-head, if a stick of
known length lie held (_)Ut parallel with the earth's
surface — i.e.. horizontalh' — a shadow will be cast
verticallx' down the bod\- of the person holding the
stick, which will be ver\- long at mid-day, decreasing
to zero at sunrise or sunset. Also at any particular
period of the year the length of the
shadow, measured vertically, cast hv
a horizontal stick, will \ar\' with the
declination of the sun and with the

month m

a [)iece of thread is
lurpose, and spin the

time of da\- — being, in general, shorter

^

opposite the \-ertical for the da\- of th
question.

Hold the c\iin<ler \-ertica
attached to tiie cap for the

dial round until the shadow cast b\' the gnomon
down the cNJintler is \ertical. The end of the
shadow will show the time of day, the reading
being taken from that vertical most nearl\- coinciding
with the shadow, while the curves allow an accurate
interpolation to be made.

corres-
above

;i\en length
ength of the

in winter than in summer.

The gnomon of the sundial
ponds to the stick in the
illustration, and for a gnomon ol
it is a sim[)le matter to calculate tlu'
shadow which ought to be thrown on any particular
da\' of the year, at any time of the day. As it
is not possible to construct a dial with three hun-
dred and sixty-five sides, a side for each dav of
the year, a certain interval oiiK on
the cylindrical surface of the dial can
be allotted to each month.

These intervals are shown Iw the
vertical divisions and suii-di\isions on
the de\'eloped plan.

The numbers 1, 2, ,5, 4, and so on,
refer to the hours of the da)' — 1 for
one o'clock, and so on.

At 12 o'clock the sun is high oxer-
head, so that one curve represents this
hour, but as the sun's angle at 1 1 is
the same as it is at 1 o'clock, each
of the other curves can represent the
hours in pairs before and after noon.

The vertical for December indicates
that the sun rises about seven, because
onlv the curves for 7. X. 0, 10, 11 and 12 o'clock
pass through it. On the other hand the June
vertical starts with a point almost at four o'clock,
all the curves subsequent to this number being
marked upon the vertical.

Although the above description is, of necessity,
somewhat lengthy, yet the manner of reading the
dial is simplicity itself.

Take the conical top out of the cylinder and after
j)Utting the gnomon in a horizontal position replace
the cap, jamming it firmly into the top of the
cylinder so as to hold the gnomon in that posi-
tion (Figure .^), but before jamming turn the top
round so that the sharp edge of the gnomon rests

Figure 5.
riie gnomon.

FiGUR?: 6.

Angle between the two planes
HOADC and K()ALC=sun's
doclinatiiin on any day of
the year. At Midsnmnier
these two planes will coincide.

No \ery great accuracy can be ex-
pected from such a simple and cheap
instrument, but an accurac\' ecjual to
that of a small sundial might be
anticipated.

Like all sundials, this curious instru-
ment can only be used in the latitude
for which it is designed, though in such a small dial
considerable margin in this connection might be
allowed.

This particular dial is (juite modern in appear-
ance, though there is no indication of the place
of manufacture upon it. The writer was given to
understand that it was found in use
amongst the shepherds in the North of
I'rance, though the princijial dimen-
sions of the dial, including the gnomon,
are in inches, and denote in consequence
an English or American origin. It is
almost certainh' a copv of some older
f( inn.

The elementary mathematical theor\-
(■\ol\L'd is as follows (see Figure 6) : —

(1) AOI5CD is the plane of the sun
at meridian.

(2) KOAFC is the equatorial (ilane
at right angles to this plane.

t J) KOALC is any plane within 23A"
N. or S. of the meridian plane.

Then if the sun is supposed to rise at A and set at
C on an\' particular da\' of the \'ear, it will pursue
such a path as ALCKO.

Suppose P be an\' point on the same jiaths on this
day. Join PO, PB. BK and KO.

Then PKBO is a right-angled spherical triangle of
which the angles POK, KOB are known, KOB
being the sun's declination from the vertical and
POK being 90 — hour angle.

The soluticju of this triangle will lie found in any
good work on surveying, and is of the form

cos (( = cos j8 cos y,
where a ("i and y are the angles of the spherical
triangle.

DISCS FOR SOLAR PROJ I-XTION.

By JOHN McHARG, M.A.

Ox the following pages are given four more of the Maps for Solar Projection wlm h com[)lete the set. Number
V. was printed on page 199 of this volume, while Numbers I., II. and III. appeared in the June issue for
this \-ear on pages 207 to 209. It is intended to rejirint the series and issLie them as a separate publication.

I\'. Latitude of Centre + 3°

307

VI. Latitude of Cc-ntre + 5°

308

\U. Latitude of Centre + 6°.

309

VIII. Latitude uf Centre + 7°.

310

CORRESPONDENCE.

ASTRONOMICAL
7"o the Editors of

QUERIES.

■ Knowledge."

Sirs, — In the course of Astronomical study I have lately
found difficulty on three points. I am venturing to lay these
points before your readers, in the hope that a solution may be
found me through the niediuni of vour columns.

Let a denote tl

Figure I.

?nii-niajor axis, A O.
.. minor .. C O,

Ihpticity

Then R

AO

r „ ,, variable radius vector, P F,

T ,, „ complete period of revolution,

S „ ,, perimeter of the ellipse, that is, the rectified

complete path of the body,
R ,, „ arithmetic mean of the greatest and least

values of ;-,
Rf ,, „ time-average value of ;-,
Ra t, ,. angle-average ,, „
Ro M .. orbit-average „ „

BF+AF_RO+FO+AO-FO_

'' Vi''-

-"[

1 + '-^'

R..=.

R.,

de = b.

- ds = a.
S

I. — A uniformly illuminated surface, \vhate\er be its form
and whatever be the angle made by the line of sight to its
component parts, will appear uniformly illuminated where-
ever the eye be placed ; the amount of light that reaches the
eye will be proportional to, and depend only upon, the intensity
of the illumination and the solid angle subtended by the
boundaries of the surface at the eye. A familiar illustration
of this is the case of an opal gas globe illuminated by a gas
flame at its centre. The globe appears as a fiat uniformly
illuminated disc from all positions. This phenomenon is well-
known and readily explained. In the case, however, of a
surface illuminated by a point-source of light, and shining by
reflection, the intensity of illumination varies with the angle
of incidence, being, in fact, proportional to the cosine of that
angle. Considering the case of a sphere, the intensity falls off
to zero at the terminator of the illuminated portion. To an
observer, then, such a sphere does not show the same intensity

at the different portions of its surface ; and the amount of light
that reaches the eye depends not only on the solid angle the
illuminated surface subtends at the eye. but also on the
varying intensity of illumination, due to the varying angle of
incidence of the light.

Now the Nautical Almanac, in calculating the time of
greatest brilliancy of Venus, assumes that the illuminated
portion of the planet visible from the earth is of uniform
intensity, and that the brilliancy varies only with the solid
angle subtended at the earth. Godfray in his " Treatise on
Astronomy " gives the same method of calculation. Why
should an approximately accurate result be expected on such
an assumption ?

II. — What is the usual interpretation of the expression
'■ mean distance " as applied to the radius vector of a body
revolving in an elliptical orbit about its primary ?

The following interpretations occur to one, and there are
doubtless others.

(a) The arithmetic mean of the greatest and the least value
of the radius \ector, which has the value a (see Figure 1).

(6) The average value at eijual intervals of time which is
a (l+e';2l.

(c) The average value at equal increments of the angle
made by the radius vector, which is /).

id) The average value of the radius vector at equal intervals
of path of the body in its orbit, which is a.

One reads frequently of the '" mean distance " without
qualification ; its value is generally taken to be the semi-
major axis ; but the time-average value would seem to be an
important interpretation, and this is not the semi-major axis.

III. — It is recognised that the secular acceleration of the
moon's mean motion is partly accounted for by change in the
perturbation of the moon by the sun as the earth's orbit
slowly becomes less elliptical. Here is a difficulty I cannot
solve. I will endeavour to state it.

With decrease of ellipticity the time-average value of the
earth's radius vector, a d+c" 2). grows less. As the radius
\ector decreases the sun's perturbing influence on the moon
increases. With increased perturbance the moon's motion is
retarded. But the moon is known to be accelerated. There
is then some fiaw in the above reasoning which I cannot
find. I crave help from one of your astronomical readers.

Hampstead, X.W. C. O. BARTRCM.

THE FOURTH DIMENSION.
To the Editors uf " Knowledge."

Sirs, — I was very greatly interested in Mr. A. L. Annison's
paper on "The Fourth Dimension " appearing in your issue
for June, 1911. The writer, I think, very clearly shows that
there is no valid reason why the '" fourth dimension " should
not actually exist : but, it may be asked, does this amount to
a proof that the "' fourth dimension " does actually exist ?
1 hardly think that we may answer, yes ; and it is for this
reason that I venture to write to you, sirs, in order to call
attention to my own work upon the subject, because I believe
that I have been able to demonstrate, assuming the truth
(1) of the Euclidean conception of space, (2) of the principle
of the continuity of mathematical law, that the fourth and
higher dimensions do actually exist ; the existence of a third
dimension of space implying that of a fourth, and so on, to
infinity. As to the first of the above postulates (the truth of
the Euclidean conception of space), all our experience supports
it ; but at the same time, I believe the wording of my proof
might be modified so as to apply in the cases of the elliptic
and hyperbolic space-hypotheses as well as the parabolic or
Euclidean. As to the second postulate, this is altogether in
accord with all our experience, and is. therefore, rightly
employed in discovering facts which lie without the same.

A very brief statement of my proof, which was originally

311

312

KNOWLEDGE.

Al'GUST, 1911

presented at a meeting of the Polytechnic Mathematical
Society, appeared in a letter to the then editors of
" Knowledge," which appeared in " Kno\vi.kdge " for July.
1908 {\'o\. V, page 157). A fuller statement will be found in
my " Matter. Spirit and the Cosmos " (Rider. 1910). Chapter 6.
together with some speculations bearing upon the same
subject.

Thanking you in anticipation for affording this letter the
hospitality of vour columns.

H. STANLEY KEDGROVE.
The Polytechnic.

Regent Street. W.

OBSERVATION OF URANUS AND MARS.

To the Editors of " Knowledge."

Sirs. — Uranus was observed on the early morning of July
1st, being located by aid of the circles on the equatorial of my
three-inch Mogey refractor; this is the first observation of
this planet I have made this year. It was pale blue or green
in colour, quite bright, and very attractive in its field of few
other and fainter stars. It presented quite a sensible disc,
power eighty-four diameters, and appeared as it usually does,
i.e., pale and diffused, like a star slightly out of focus. It is
of about magnification six, probably some brighter, and is

easily visible in the one and one-eighth inches finder of my
three-inch telescope; as it is the only bright star in its
locality, it should be easily distinguishable even with an opera
glass. Probably Uranus would be visible to the naked eye in
clear air. especially as it is in an isolated position, to speak
relatively.

Mars was also observed on the morning of July 1st. The
disc was rather large and very reddish, powers eighty-four
and one hundred and twenty-six. and was very beautiful ;
near a small star. The South polar cap was easily observable,
eightv-four and one hundred and twenty-six diameters, in my
three-inch instrument, and was attractive, being almost circular
and very white. At and around the South polar regions,
the disc was lighter than elsewhere and seemed to shade off
gradually into the cap. At or near the equatorial regions, an
apparently large continuous marking, running horizontally,
was seen, very similar to those visible in the fall of 1909,
through my two and a half inches refractor. This marking was
dark green in colour, and extended nearly the entire distance
across the disc, and at places was observed to be somewhat
irregular in outline. The planet also seemed to be slightly
gibbous on this date. FREDERICK C. LEONARD.

LEON.\Rb Observ.\torv,
Madison P.\rk,

Chicago, U.S.A.

SOL.AR DI.SrURBA.XCES DURING JUNE, 191 1.
Bv FR.\NK C. DEXNI:TT.

The Sun has been very free from spot disturbances during
the month of June. On the eleven days June 7. 8, 10-14, 16.
18, 19 and 24. there appeared to be a complete absence of
disturbance, and probably the 25th should be added, although
no observations have come to hand for that date. Only
faculic markings were seen on the disc upon the nine days
June 6, 9, 15, 17, 20-22,27 and 28. and some of these appeared
to be temporary in character. The longitude of the central
meridian at noon on June Ist. was 102 45'.

No. 24 remained visible until June 5th. and so appears on
the present chart in its position on the 2nd.

No. 24a. — .A group of four small pores. 15,000 miles in
length on the 2nd, which in the afternoon appeared to be
de\ eloping into an elliptical outbreak, but only the leader
continued visible on the 3rd. The area was marked by
facnlae, upon the 4th and 5th. which was joined to that
surrounding No. 24.

No. 25. — A group of pores, three in number, only seen on
June 23rd.

There was a greyish pore visible on the morning of June
28th in a pale faculic cloud near longitude 57°. South latitude
6°, marked by a cross on the chart, but not seen in the
evening.

No. 26. — A spotlet. without penumbra, seen on the 29th and
30th only.

Whether studied with the telescope or spectroscope, the
amount of disturbance is very small. The spots are generally
of an evanescent character, and are mostly found recurring in
the same districts of the solar surface, as may be noted by
comparing the monthly charts together. Of the thirty-one
spot disturbances recorded dm'ing the past six months seven
were northern. Of these one was in longitude 7°, four
between 103° and 146", one close to the equator, 170°, and
one at 226'. Of the twenty-four southern ones nine are
between longtitndes 35° and 86°, two between 120" and 130°
eleven between 165" and 203". and the remaining two between
243' and 253°. The intervening areas are thus left seemingly
without disturbance, in fact, from longitude 146° right round
to 103 — 317 — in the northern hemisphere, only three tiny
outbreaks occur. The longest vacant district in the southern
hemisphere — 140° — is between 254° and 35", three smaller
ones occurring between 86° and 120^ 130° and 165°. and 203°
to 243°.

Our chart is constructed from the measures and drawings
of Messrs. J. McHarg, E. E. Peacock, and F. C. Dennett.
Absence from home has unfortunately prevented Mr. Buss
from sending in his work in time to be included this month.

DAY OF JUNE, 191 1.

3

7

6

5

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1

50 2,

P

1 '"5

7

f6

?5

^

+

^5

^e

?,'

V

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'f

(

16

7

Jr

'^

1?

1

'P

?

s

30

26

10

1?

>

nl

:

uy

-•

2ft

20

£•

a

2*.

"--

25

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B

0 10 JO 30 to so 60 70 aO 30 100 no 120 150 140 ISO 160 170 180 190 200 210 220 230 »0 250 260 270 2S0 290 300 310 J20 330 j-M JSO 360

NOTES

ASTRONOMY.

By A. C. D. Crommelin, D.Sc, B.A.

COMETS. — Two comets have been found in the last few
weeks. One is Wolf's Periodic Comet, a well-known member
of the Jupiter family, which was photographically detected by
Its original discoverer, Dr. Wolf, when only of the fifteenth
magnitude. It was extraordinarily close to the place
predicted by M. Kamensky, the error being 0^-5 in R.A., 6" in
Decl. This comet will not pass perihelion till February, 1912,
and is, therefore, still at a considerable distance from the Sun.

The other comet is an unexpected one, and promises to be
faintly visible to the naked eye. In fact, M. Belopolsky gives
its magnitude as 4-0, on July 9th, and states that it had a tail
i" in length, in direction 285 ". The comet was discovered on
July 6th, by Mr. Kiess, at the Lick Observatory, and will there-
fore bear his name. Professor Kobold, of Kiel, has deduced
these elements: Perihelion passage. 1911, June 20-64, Berlin
M.T., Omega 99° 32', Node 172° 28', Inclination 148° 39',
Perihelion distance 0-7932. The comet is now receding from
the Sun, but at the same time its position in the sky is
becoming more favourable, as it is getting 1A° further from
the Sun in angular distance each day, and is also rapidly
approaching the Earth, which it will continue to do till nearly
the end of August, when it will be distant some thirty-five
million miles, and observable for the greater part of the night.

.\n interesting feature in this orbit is its close resemblance
to that of the comet 1790 I, which was discovered by Miss
Caroline Herschel in January, 1790, but only seen on four days.
When the new comet has been observed for a month or so, it
will be possible to decide the cjuestion of identity. Even a
close resemblance of orbit is not a proof of identity, for there
are several instances of families of comets that travel in
practically the same path. The most striking instance is that
of the very brilliant comets of 1S43, 1880, 1882, 1887. There
can be little doubt of common origin in these cases.

This generation has probably seen its last of Halley's
comet. Professor Barnard followed it visually till May 2+th,
and it was photographed at the Lick Observatory till May 27th.
It was then outside Jupiter's orbit, and the total period of
observation is one and three-quarter years. Doubtless further
attempts at photography will be made when it emerges from
the sun's rays in the autumn, but their success is doubtful.

It is likely that the large number of periodic comets that
have been visible during the last two years has distracted the
attention of observers from the search for new ones. I would
suggest this as a promising field for amateurs with leisure for
sweeping ; a three-inch telescope with a low-power eyepiece is
sufficient equipment ; I think few have seriously taken up
this work without success before very long.

THE EIGHTH SATELLITE OF JUPITER.— In
addition to the photograph obtained at Helwan, Egypt, Dr. Wolf,
at Heidelberg, and Mr. Innes, at Johannesburg, have succeeded
in obtaining images of this seventeenth magnitude satellite.
This success is very satisfactory in view of the fact that it will
be unobservable at Greenwich till 1915, and gives ground for
hope that the interval will be bridged over satisfactorily.
A number of minor planets, both old and new, were recorded
on the plates. About seven hundred of these little bodies are
now definitely numbered, and hundreds more have been
observed, but their orbits are not accurately known. The
zone shows no signs of exhaustion, and the calculation of their
orbits and ephemerides is a severe tax on the Berlin
Recheninstitut.

TOTAL ECLIPSES. — The eclipse of last April was not a
complete failure as observed from Vavau and neighbouring
islands in the Pacific. Records of the general form of the
corona (approximating to the type of sunspot-minimunr) were
obtained and we may hope for a few spectroscopic results.

But evidently the great humidity of the climate was a draw-
back, as the fall of temperature caused condensation of vapour.
There is a favourable totality in October, 1912, the track
crossing Brazil, and emerging a little west of Rio. It is
expected that two parties will go from this coiintry to view it,
and doubtless other nations will be represented. In April.
1912, there will be totality for a second or two in Portugal
and N.W. Spain. It will be a particularly favourable occasion
for obtaining impressions of the reversing layer all round the
sun, and it should be possible to photograph the inner corona
with rapid plates. Great care will be required in selecting
a station, its accurate longitude and latitude must be
known, as the track of totality is less than a mile broad.
Those who desire to witness the eclipse as a spectacle without
doing serious work may go to the north-west outskirts of Paris.
There will not be absolute totality there, but I anticipate that
there will only be a few small patches of sunlight through
depressed portions of the moon's limb, not a complete ring.
This eclipse is a return after the triple Saros of that of 1858,
the last central eclipse in the British Isles. The next will be
1921 (annular, Hebrides and Shetlands) and 1927 (total
across Wales and England).

BOTANY.

By Professor F. Cavers, D.Sc, F.L.S.

ORIGIN OF CHLOROPLASTS IN SEEDLINGS.—
Two widely divergent views have been held with regard to the
origin of chloroplasts (chlorophyll grains) in seedlings.
According to one \iew. the chloroplasts originate directly
from the general protoplasm of the cell, the mature seed itself
containing no chloroplasts. Another group of investigators
maintains that the protoplasm of the cell never gives rise to
chloroplasts, but that the fertilised egg contains plastids
derived directly from the parent plant, and that during
development of the egg these multiply and thus provide every
cell of the embryo with chloroplasts.

.According to Sachs, the chloroplasts arise in the young cells
by the separation of the protoplasm into portions which
remain colourless and others which become green and sharply
defined. He held that the process takes place by very small
particles, originally of a different nature from the apparently
homogeneous protoplasm in which they are distributed,
collecting at definite places and appearing as separate masses.

Mikosch, after examining the seeds and seedlings of the
sunflower, concluded that there are no plastids in the resting
seed, but that during germination the chloroplasts arise
directly from the protoplasm of the cells, owing to condensa-
tion of the protoplasm in definite places, this condensation
being probably due to loss of water in these parts, which soon
become green. The process occurs independently of light,
and the bodies thus formed are at first rod or spindle shaped,
but later assume the typical disc shape of the chloroplasts.

Belzung, after a long investigation of the ripening seeds,
mature resting seeds, and seedlings of many plants, came to
the following conclusions : (11 the free growth of starch grains
can take place without the intervention of plastids; (2) the
chloroplasts are formed directly by dift'erentiation of the
protoplasm; (3) the chloroplasts can also be formed at the
expense of the starch grains which have their origin in the
protoplasm of the cell. According to Belzung, the young
embryo contains no chloroplasts, the starch grains formed in
it are laid down in vacuoles of the protoplasm, and the green
colour of the embryo in many plants is due to green pigment
distributed through the protoplasm. No chromatophores are
present in the embryo, consequently there are none in the
mature seed. At germination the simple starch grains of the
seed disintegrate, and numerous compound grains of transitory
starch appear in various parts of the protoplasm. Each large

313

314

KNOWLEDGE.

August. 1911.

vacuole is composed of from two to five smaller ones, in each
of which a small starch grain is formed, and as the componnd
grain thus formed disappears, the green pigment passes in and
thus a chloroplast is formed.

Meyer and Schimper, on the other hand, concluded that the
origin of chromatophores does not take place in the young cell
in any of the cases investigated by them, but that all chromat-
ophores are derived from other cells in which they previously
existed, increasing in number by division. Schimper found
chloroplasts in the embrvo-sac and the egg-cell, and concluded
that the chloroplasts thus present in the young embryo
persist in the ripening seed, but become colourless and lose
their function, again becoming green and functional when
.germination occurs.

Bredow made extensive observations on seeds, and found
that chloroplasts were always present, though often staining
very poorly and being therefore hard to detect. Bredow used
chiefly picric acid, which colours all proteid material yellow,
but stains plastids more deeply than the other cell contents.
He found that the chloroplasts of the seed increase during
germination by simple fission, and also by the division of one
chloroplast into as many as ten or twelve small ones by
numerous irregular divisions. He pointed out that the green-
ing of these numerous small bodies led the earlier observers to
conclude that the chloroplast originates directly from the
protoplasm of the cells of the seedling.

Famintzin made still more detailed obser\ations on the
origin of chloroplasts in seedlings, and especially on the manner
in which the chloroplasts, if present in the seed, increa.se by
division. Applying various microchemical reagents and stains,
and using chiefly thesunflower. Famintzin wasabletodistinguish
between the protein grains on one hand, and the chloroplasts
and other protoplasmic structures on the other. He found that
most of the chloroplasts in the resting seed lie in the film of
protoplasm which surrounds each of the protein grains. On
placing fresh sections in the light, he observed that these
small bodies on the protein grains took on a yellowish colour,
and by identifying these bodies in various stages of the seed-
ling, he concluded that the sunflower seed contains chloro-
plasts. which by simple fission produce those of the seedling.

The latest investigator of this subject is Miller iBof.
Gazette, 1911), who has just published the results of his
observations on the sunflower, applying the modern methods
of fixing, microtome section- cutting, and staining. Miller
confirms the statements of Bredow and Famintzin, who showed
that chloroplasts are present in the resting seed and gi\e rise to
those of the seedling. Instead of beginning with the young
embryo, and working onwards to the seedling, however. Miller
has adopted the better method of working back step by step
from the seedling to the seed. .According to Miller, the
chloroplasts in the early stages are present in the usual posi-
tion in the cell, namely, just within the cell wall. He found
the numerous small bodies clustered about the protein grains,
but he does not agree with Famintzin that these are the
chloroplasts.

.ALG.A.L CO.AL. — The petroleum-yielding coals known as
bog-head, cannel, and so on, have been supposed to owe their
origin to .Algae. This view, put forward by Renault. Bertrand.
Potonie. and other workers in fossil botany, has been some-
what widely accepted. The chief evidence of such an origin
is the occurrence in these coals, as well as in bituminous
schists and oil shales, of abundant spherical or oval bodies,
often arranged in layers, these bodies being interpreted as
colonial Algae. They have recently been investigated by Jeffrey
{Proc. Anier. Acad.. \'ol. XLVL, 19101, who has elaborated
a method for obtaining nvnnerous thin sections in series, the
result being that the structure, and by inference the nature, of
these bodies can be brought out with a clearness not hitherto
possible.

Jeffrey shows that these bodies are certainly not .\lgae, but
the spores of Pteridophytes and other fern-like plants, which
formed an important part of the Palaeozoic flora and which
have always been regarded as largely responsible for the

formation of ordinary coal. This conclusion destroys the
Algal theory of the origin of petroleum and similar substances,
and refers such products to the waxy and resinous spores of
Pteridophytes, which were laid down on the bottoms of the
shallow lakes of the Coal Period. These lacustrine layers,
the mother-substance of petroleum, form either cannels, bog-
heads, or bituminous shales, according to the proportion of
spores and the admixture of earthy matter. Pressure and
temperature, either separately or combined, in the presence of
permeable strata, have brought about the distillation of
petroleum from such deposits.

ALKALOIDS AS PLANT FOOD.— It has always been
supposed that the various alkaloids found in plant tissues are
purely waste products, not entering again into metabolism.
However, some recent observations by Comere [Bull. Soc. Bot.
France, Vol. LVIL. 1910) appear to show that some of the
alkaloids can be used as food materials. In fact, Comere
finds that some alkaloids can be used by plants as the sole
source of nitrogen. He worked with the freshwater Algae
i'lotliri.x and Spiro<iyra. The alkaloids used (morphine,
atropine, cocaine, quinine, and strychnine) were added
gradually as assimilated, so that the plants wei-e never
subjected to strong solutions. The plants readily assimilated
morphine and atropine, and less readily cocaine. Quinine,
however, could not be assimilated, while strychnine proved
very poisonous even in great dilution.

KESFKVF FOOD IN BORDERED PITS.— It has
become a commonplace that the most familiar plant repays
renewed investigation. A short time ago, it was found that
the so-called " scalariform tracheids " of the common male
fern and the Bracken, which ha\'e served generations of
botanical students as types of the fern alliance for dissection
and laboratory work, are in reality true vessels similar to
those in the wood of the higher plants. Recently, Lakon
[Bcr. ilciitscli. bot. Ges., 1911), has shown that the familiar
bordered pits in the tracheids of the common coniferous trees,
Scots pine and spruce fir, contain at certain stages numerous
starch grains and oil drops, and therefore evidently serve as
storehouses of food in addition to their ordinary functions in
connection with transport of water. Lakon states that while
making observations on the reserve foods in various trees, he
noticed starch and oil in the pits of the tracheids. At first he
thought that some starch and oil must ha%e simply got into
these pits by accident from the parenchyma cells of the
medullary rays, in the process of section cutting. However,
on making more careful preparations he proved that the starch
and oil actually occur in the pits, even where the tracheids are
not in contact with parenchyma cells, and he found them in
microtome sections of material embedded in paraffin — that is.
under circumstances which precluded the possibility of the
accidental passage of starch and oil into the tracheids from
the other tissues of the wood.

Having clearly established the fact itself, Lakon proceeds to
its explanation. Two alternatives are possible: — (1) the
starch and oil may have been left behind in the pits while the
tracheid was developing from a living and food-bearing cell;
(2) some of the protoplasm of the tracheid-forming cell may
have persisted in the pits, the glucose in the cell-sap being
later converted into starch and oil. Lakon inclines to the
second explanation. He finds that during the winter, when
the parenchyma cells of the rays contain only oil, the pits
of the tracheids also contain oil and not starch ; and that
in spring, when the parenchyma cells contain much starch and
little oil, the same change occurs in the pits. Since a change
of this kind could hardh' occur in the absence of living
protoplasm, it appears probable that such protoplasm is
present in the bordered pits, and Lakon was able to demon-
strate this in some cases.

Lakon states that in the literature there is only one recorded
case where protoplasm, starch and oil occur in the fully
developed conducting tissue elements of vascular plants,
namely, in the stem of various species of plantain iPlaiitago).
In the conifers investigated by Lakon, the protoplasmic

August. 1911.

KNOWLEDGE.

315

remains, with the starch grains and oil drops, may persist for
several years ; they occur only in the younger parts of the
wood, but as far inwards as the fifth or si.xth .annual ring.

AMBROSIA FUNGI. — In continuing his interesting series
of papers on Ambrosia Fungi, which have already been noted
in " Knowledge," (May, 1910), Neger adds some further
details (Ber. dcutsch. hot. Gcs., 1911). Neger applies the
term " ambrosia " to the Fungus cells which the associated
insects eat, as well as to the insects themselves. The insects,
including various beetles, mites, and so on, bore in the bark and
wood of trees, and the cavities of the galls or tunnels they
produce are lined by the Fungus layer which produces the
special spherical " ambrosia " cells, serving for the food of the
insect. This is, doubtless, a curious case of symbiosis,
or mutually beneficial partnership, the insects on one hand
being well fed by the Fungus, while the Fungus on the other
hand takes advantage of the boring of the insects to gain
entrance to the plant tissues and also gets a better supply of
air opened up for it.

In his last paper, Neger concludes that the association
between the boring beetles and the Fungus is an adaptation
on the part of the former to life in wood poor in food
substances. The ambrosia-seeking insects are much commoner
in the warm and tropical zones than in the cool temperate
regions, and they occur not only in standing trees but also in
fallen ones, which are not j-et dead. In the tropics, such
insects often cause great damage to valuable trees yielding
rubber, coftee. tea, and so on. This destructive action is not due
merely to the attacks of the insects themselves, but to the fact
that they introduce the Fungus to the conducting tissue of the
wood, and probably more harm is done by the parasites which
gain admittance in this way than by the Ambrosia Fungus on
which the insects feed.

Neger has cultivated the Fungus found associated with
various wood-boring beetles (chiefly species of Xyleboriis) in
order to obtain the spores and to determine its systematic
position. .Apparently the majority of the Ambrosia Fungi
are either identical with, or closely allied to, the simple
Ascomycetous genus Endomyccs.

CELLOSE AND CELLASE.— It has long been known
that, just as starch is converted into grape sugar (glucose) by
the action of the ferment diastase, so cellulose — the chief
component of the cell-walls of plants — is changed into glucose
by the action of the ferment cytase. If, however, the
hydrolysis of starch is incomplete, the resulting sugar is malt
sugar (maltose), and it has recently been found that the
corresponding product of incomplete hydrolysis in the case
of cellulose is a substance called cellose. Bertrand and
Holderer iBiil! Soc. Chim. France, 1910), have discovered
that cellose is converted into glucose by a special ferment,
cellase. These authors find that cellose is not acted upon by
such ferments as maltase, sucrase, and emulsin. This
discovery indicates that there are probably many more
ferments in plants than have hitherto been recognised, and
that like so many other ferment actions, the digestion of
cellulose takes place in several stages.

THE ECOLOGY OF CONIFERS.— The leaves of the
conifers show markedly " xerophilous " structure, having thick
cuticle, sunken stomata, reduced leaf-surface, poorly-developed
air spaces, and so on, — all features characteristic of plants
which grow in physically or physiologically dry places, and
which must therefore check loss of water by transpiration. It
is somewhat difficult, however, to reconcile this xerophilous
structure with the fact that conifers often grow in places where
app.arently there is an abundant water supply, and it has been
supposed that in such cases the xerophily is a character fixed
by heredity. It has been suggested that the xerophilous leaf
structure of conifers is due to the hereditary tracheidal
character of the wood — that is, the presence of narrow
trache'ids instead of wide and open vessels — and the consequent
limitation of the rate of flow of the water current. But this
explanation breaks down, for the Larch shows a rate of flow
of water equal to that seen in most dicotyledonous plants.

The assumption that a character shows hereditary fixity is
one which calls for independent evidence, quite apart from the
supposed incompatibility of structure and habitat. The
recent work of Groom {Ann. Bot., 1910) has shown that it is
fallacious to judge of the xerophily of a plant from its leaf
structure .alone, and that a factor of fundamental importance
is the total leaf area. Groom considers that the northern
evergreen conifers are " architectural xerophytes," in which
the extensive surface exposed by the evergreen leaves as a
whole renders it necessary for the individual leaves to be
xerophilous in structure. He thinks it possible that concurrent
increases in the assimilatory surface, and in the zerophilous
devices generally, increase assimilation in relation to trans-
piration ; but that in the absence of detailed statistics bearing
on the subject it is impossible to explain why the conifers
should have adopted the device of having a large aggregate
surface with a greater degree of xerophytism.

Coulter and Chamberlain (Morphology of Gymnospcrms)
adopt a similar view, implying that the plant is extremely
plastic and that in matters of adaptation it will always come
to adopt that habit and structure which give the greatest
degree of efficiency under the given environmental conditions.
Coulter and Chamberlain consider that the development of the
small and stift" needle-like leaves or the concrescent scales of
conifers from their assumed broad-leaved ancestors " cannot
be regarded as the result of a general tendency among
Gymnosperms quite unrelated to conditions of living ; the leaf
is too variable a structure and too closely related in its work
to external conditions to permit such an explanation of its
changes."

Compton (Neiv Pliytologist. March, 1911) criticises these
views, and urges that the small-leaved type is the primitive
one for conifers and is extremely stable. The primitiveness
of small leaves in conifers is bound up with Seward's well-
known theory that conifers arose from club-mosses
(Lycopodiales), but even if the ancestors of the conifers were
large-leaved plants, it must be admitted that the same type of
small-leaved conifers had persisted from later Palaeozoic times
to the present day. The variety in habitat of modern conifers
is correlated with less variety in their structure, relations of
leaves to stem, size of leaves, and so on, than in the case of
Angiosperms. The larch, with its deciduous habit and lesser
degree of structural protection against transpiration, but with
its retention of the small leaves, is a striking example of the
persistence of the typically coniferous form of leaf. The
deciduous species of swamp cypress {Ta.wdiiini) and
Glyptostrohiis also inhabit swampy places without modifica-
tion of the type of leaf form. In Pliyllocladiis the plant has
resorted to the device of producing flattened branches instead
of increasing the size of its leaves.

It would appear, therefore, that the coniferae have small
power to vary the character of their leaves. The predominant
types — the needle-like leaves of pines, firs, larch, cedar, and
so on, the lineal lanceolate leaves of yew, and so on, the scale-
like appressed and concrescent leaves of cypress, and so on, —
are all closely related to each other. The leaf development is
in all cases small compared with that of the stem — that is, the
conifers are fixedly small-leaved. This appears to be con-
nected with the absence of lateral veining of the vascular
bundles in the leaf. In most cases a single or double bundle
runs from end to end of the leaf without branching ; and even
in -Araucarias and other forms, where the leaf is broader and
many-veined, there is not found that copious lateral branching
and anastomosing of the veins which is associated with the
free branching of so many dicotyledonous leaves. The failure
of the bundles to branch is to some extent compensated
by the development of transfusion tissue — this is also found in
some fossil lycopods where the same limitation of the power
of branching prevails, along with small leaves and often
xerophilous structure.

Hence it appears that the conifers are rigidly small-leaved
forms, and that the power of freely adapting themselves to
ecological conditions is strictly limited by the lack of plasticity
in leaf structure. It is suggested that the lack of ability of
the foliar vascular system to branch with ease is one of

316

KNOWLEDGE.

August. 1911.

the causes which ha\e contributed to keeping the leaf sm.iU.
and that this faihire may possibly be associated with the
presence of transfnsion tissue, which, though valuable in itself
under the circumstances, may tend to prevent improvement in
other directions, such as that of free pinnation of the veins.

Given this cramped hereditary type of structure, ecological
adaptation appears to ha\e been the result of two processes
going on simultaneously: (1) the development of enormous
numbers of the rigidly-constructed leaves with a view to
increased assimilation and growth, and (2) the production of
xerophily in the indi\idual leaves as a compensation for the
resulting increase of surface. It thus seems clear that the
hereditary factor is of great importance in the ecological
relationships of the conifers. It is conceivable that ecological
.adaptation may be achieved as efficiently by a suitable
modification of the small-leaved type as by another kind of
modification of a broad-leaved type — in fact, more than one
kind of mechanism may be well adapted to a given set of
external conditions. The conifers, however, are predisposed
to the adoption of " architectural xerophily " as their mode of
adaptation by the persistent hereditary factor of microphylly
(possession of small leaves).

THE MAIDENH.^IR TREE [GIXKGO BILOBA).—

One of the most interesting groups of Gynmosperms is that
which is now represented only by the Maidenhair Tree. The
Ginkgotype is of special importance because its reproductive
organs show many resemblances to those of the lower
Gymnosperms (Cycads and Cordaitalesl, while its vegetative
anatomy resembles in many ways that of the Conifers, so
that it may be s.aid to form a connecting link between these
groups.

The Maidenhair Tree, as the sole survivor of a family which
was well represented in the Mesozoic Period, and perhaps
much earlier, has naturally attracted a great deal of attention
from botanists, and it is proposed here to summarise some of
the literature on Ginkgo published during the last few years,
including the most recent accounts.

Ginkgo is almost unknown in the wild state, though reported
by travellers in the forests of western and south-western
China, but it has been extensively cultivated, first in China
and Japan, and later in l-'urope — there is a fine tree in Kew
Gardens, for instance. .Apart from the strong main trunk and
wide-spreading branches, it hardly resembles in habit any of
the other Gymnosperms. while its deciduous leaves, having
a long slender stalk and a broad wedge-like blade with
repeatedly forked veins (strongly suggesting the leaves of
Maidenhair Fern), are so characteristic that they form
unusually trustworthy evidence of the existence of the
Ginkgoales when found in the fossil state. The tree reaches
a height of about one hundred feet. The branches are of
two kinds ; the long shoots bear scattered leaves, while the
short ones are dwarfed, slow-growing, and bear few leaves in
a cluster. A dwarf shoot may after several years become a
long shoot, bearing scattered leaves, and may then resume the
slow growth of the dwarf shoot ; sometimes it undergoes
branching.

The general morphology and anatomy of Ginkgo have been
described by Seward and Gowan (Ann. Bot.. 1900) and in
greater detail by Sprecher in his invaluable monograph of this
plant (Geneva, 19071. while various details have been added
by recent writers. The stem shows the general structure of a
conifer, having a narrow cortex, a thick compact zone of wood
produced by a persistent cambium layer (contrasting with
Cycads), and a relatively small pith (contrasting with Cordai-
tales) ; in thed warf shoots, however, the wood zone is narrow
and the pitch large. -As in the pines and other low conifers,
there are well-marked annual rings, and the tracheids have
opposite pits and " bars of Sanio."

Tupper iBot. Gaz., 1911) has shown that fre<iuently the
short shoots branch within the wood of the limb out of w-hich
they grow, this has recently been seen in a new Triassic
Araucarian, Woodwortliia, but in no other conifers so far as
known, and confirms the view that the araucarian conifers
are an old group and have possibly come from the same stock

as the ginkgoales. Tupper also describes crystal cells and
wood parenchyma as occurring in rows or series running
longitudinally through the root oi Ginkgo in radial planes; all
these rows are in contact with at least one of the medullary
rays, and Tupper suggests that the radial distribution of this
parenchyma, as compared with the tangential arrangement
seen in conifers, shows that Ginkgo is a primitive type.

The primary wood in the stem is endarch (with the earliest
wood vessels innermost, and the development of the wood
therefore centrifugal), but distinct mesarch structure ii.e.. part
of the wood centripetal, the rest centrifugal, therefore the
protoxylem not innermost) occurs in the bundles of the cotyle-
dons. The leaf receives a double bundle (leaf trace), as in all
the more primitive gynmosperms, each bundle forking at the
base of the blade and breaking up into the forking system of
veins, some of which show traces of centripetal wood and
therefore indistinct mesarch structure. The veins are not
joined up into a network, so that if a few veins are cut across
near the base of the leaf, long streaks of the leaf become
withered and dry. The leaves vary much in size and lobing,
showing e\ery transition from deeply lobed to almost entire,
though typically there is a notch at the middle of the blade.
The leaf structure resembles that in cycads ; the stomata are
chiefly on the underside, and between the veins the loose
mesophyll cells are elongated parallel with the leaf surface.

The plant is dioecious ; the flowers have no bracts, and they
are developed on the dwarf shoots. The male flowers or cones
consist of an axis bearing loosely arranged stamens ; each
stamen has a stalk ending in a knob which bears usually two
pendent stamens, sometimes three or four or as many as seven.
Miss Starr [Bot. Gaz.. 1910/ has shown that in the young
knob there develop, in addition to the stamens, patches of
apparently sporogenous tissue which degenerate into mucilage
cavities, suggesting that these cavities have replaced abortive
sporogenous tissue.

The stamen of Ginkgo suggests comparison with the
epaulet-like form seen in the " crossotheca " type of stamen
in the pteridosperms. It may also be compared with the
stamens of the cordaitales, the whole male dwarf shoot of
Ginkgo corresponding to the male inflorescence of cordaites,
which consists of a thick axis bearing bracts among which are
inserted the stamens, each stamen consisting of a long stalk
bearing at its tip a cluster of three to six erect pollen-sacs. If
the sterile sporophylls in the Cordaites cone were suppressed,
the general structure of the male flower of Ginkgo would
be attained, but in Ginkgo the pollen-sacs are borne in
a different way, being dependent on the lower side of the knob
or reduced blade of the stamen. In Antholttlius zeilleri,
regarded as the male cone of Baicra (a Mesozoic member of
the Ginkgoales), the stamens are repeatedly forked and bear
eight pollen-sacs, one on each of the ultimate divisions.
Whatever interpretation is placed on these diff'erent
structures, the facts point to close relationship between
ginkgoales, cordaitales and pteridosperms.

The female cones are much reduced, and are carried in
groups on dwarf shoots. Each cone consists of a long stalk
bearing at its tip two ovules, sometimes more, and below each
ovule there is a narrow cup or collar. The latter has given
rise to much discussion. Fujii and, later, Seward and Gowan,
were led by the study of numerous abnormal forms to conclude
that the stalk is a shoot bearing normally two rudimentary
carpels represented by the two collars. However, Shaw [^ew
Pliytologist. 190SI, examining the vascular structure of the
flower, found that the bundles of the collar show inverse
orientation, and suggested that the collar is no carpel but a
vestige of the cupule that surrounded the seeds of the
pteridosperm genus Lagcnostonia. If correct, this would
even more strongly point to an affinity between ginkgoales
and pteridosperms. Shaw regards the general anatomy of the
female axis and the occasional occurrence of an apical bud
between the ovules as proof that it is a shoot bearing two
lateral-stalked ovules, each ovule being attached to the axis
by a short pedicel, with the collar at the junction between
pedicel and ovule. On the other hand, the female axis has
four bundles, which would be expected in a stem bearing two

August, 1911.

KNOWLEDGE.

317

leaves I collars I at its apex, and when there are more than two
ovules on a stalk we find twice as many bundles in the stalU
as there are ovules at its apex — just as there should be if each
collar were a carpel.

The development of the microsporangium (pollen-sac) has
recently been described by Miss Starr, and it mature structure
and mode of dehiscence by Goebel. In development,
apparently a single hypodermal cell divides to form the tapetal
and sporogenous tissue, and. outside of the tapetum, the wall
of the sac (except the outermost or epidermis layer). The
wall consists of from four to seven layers of cells, the hypo-
dermal layer and the layer below it being thickened by fibres
serving for dehiscence. Goebel i Flora, 1902) has studied the
structure of the wall of the ripe pollen-sac ; apparently Ginkgo
is the only gymnosperm that has an endotheciuni, the
dehiscence layer or layers being of hypodermal origin ; the
longitudinal slits of dehiscence of the two pollen-sacs face
each other, and lie at such an angle that the pollen is readily
shed for wind dispersal.

The development of the ovule has recently been worked out
by Miss Carothers {Bot. Oaz.. 1907), who extends the earlier
accounts. The ovule resembles in general structure those of
cycads and cordaitales. having the typical three-layered
integument (outer fleshy, middle stony, inner fleshy), the
apical beak of the nucellus, and the pollen chamber : but the
set of bundles which in cycads and cordaitales traverse the
outer fleshy layer are not present in Ginkgo, only the inner
bundles in the inner fleshy layer. A single mother- cell (very
rarely two mother-cells) functions, and lies among a mass
of tissue which may or not be sporogenous, representing a
many-layered archesporium, but at any rate functions as a
tapetum nutritive tissue. In the mature mother-cell the
reduced number of chromosomes is eight ; the four spores
formed by division of the mother-cell may be in a row, or
three with the upper cell divided longitndinally. The tapetal
tissue increases in bulk by division, during the tetred division
of the mother-cell, and actively encroaches upon the surround-
ing nucellar tissue ; the tapetal zone in its turn begins to be
destroyed by the encroachment of the young gametophyte
(endosperm), which invades and destroys the tapetal tissue
and the surrounding nucellar tissue. The megaspore. which
has a well-de\ eloped membrane, enlarges greatly, and its
nucleus lies at the micropyle end.

Miss Carothers then describes the development of the
female prothallus (endosperm). The megaspore, after its
nucleus begins to divide, contains a large vacuole, hence the
nuclei formed by division are from the first arranged just
within the membrane, lying in the thin protoplasmic
lining layer. Up to the stage with sixty-four nuclei,
the free nuclear divisions are simultaneous, but later they
become irregular, until there are over two hundred and
fift}'-six nuclei ; meanwhile the whole ovule and the embryo-
sac are enlarging, and the megaspore membrane becoming
thicker. Previous to the formation of walls, a delicate but
distinct membrane appears on the outer surface of the
protoplasm of the embryo-sac, and to this membrane (not to
the megaspore membrane, as previously supposed) the first
walls of the endosperm are attached ; then by the nuclear
division and wall formation the prothallus becomes a solid
mass of tissue. Before this process is complete, the endosperm
becomes green, owing to formation of chlorophyll, as proved
by examination with the spectroscope, and the cells are soon
filled with starch grains — partly formed no doubt by the green
endosperm itself.

The germin.ation of the pollen-grains, the formation of the
remarkable ciliated motile male cells, and the act of fertilisa-
tion of the two (sometimes three) archegonia were fully
described by Hirase in 1898, and little has been added to his
account. Various more recent writers have, however, worked
out the development of the embryo. The embryo of Ginkgo
was formerly regarded as peculiar among Gymnosperms, owing
to the absence of an elongated suspensor, such as occurs in
Cycads and Conifers. In Bcnncttitcs. however, there was
no suspensor. Arnoldi (1903) showed that the elongated

pro-embryo of Ginkgo is differentiated into three regions : —
(1) a micropylar haustorial region (2) a middle suspensor
region, and (3) an apical region producing the embryo itself;
this brings Ginkgo into line with the typical embryology of
other Gymnosperms, though the suspensor remains short and
thick. Another peculiarity in the embryo of Ginkgo — the
complete filling of the fertilised egg with proembryonic tissue
— has lost significance by the discovery that the same thing
occurs in Dioon and probably some other Cycads. Lyon (1 904)
gave a very full account of the de\elopment of the embryo in
Ginkgo, greatly amplifying the descriptions given by Stras-
burger (1872) and other previous authors; in some cases
the pro-embryo apparently produces two embryos ; three
cotyledons occur not uncommonly, instead of two,

CHEMISTRY,

By C. .AiNswoRTH Mitchell. B.\. (Oxou.), F.l.C.

USE OF COPPER FOR WATER PIPES.— The owners
of a house in Paris, being anxious to instal copper pipes
instead of the usual leaden pipes for their water supply,
applied to the Prefect of the Seine for the necessary per-
mission. The c|uestion was therefore submitted to the
Municipal Laboratory in Paris, which reported unfavourably
upon the proposal, and also to the Council of Public Hygiene,
the head of which. Professor .\rmand Gautier, spoke strongly
in its favour. In his report he pointed out that lead was
really an unsuitable metal for water pipes, and that the purer
the water the more rapidly was the metal attacked. .'Although
the presence of sulphates in most drinking waters rendered
the risk of poisoning insignificant, it was probable, he pointed
out, that there would be trouble in the immediate future from
this cause in the case of the particularly soft waters which
have recently been supplied to the towns in the West of
France.

This danger would be entirely obviated by the use of copper
pipes, for although a dose of fifty to one hundred milligraunnes
of copper sulphate was poisonous, the system could soon
become acclimatised to much greater ijuantities, and, as a
matter of fact, several milligrammes were frequently absorbed
daily without any ill effect in the food which throughout
France was cooked in copper vessels. Experiments made by
M. Gautier upon himself had shown that no ill effects were
produced by acid food that had been cooked in copper utensils.
Long before the poisonous dose had been reached a liquid
contaminated with copper would have acquired a harsh
metallic taste which would put the consumer upon his guard,
and this would be the worst that could happen in the excep-
tional cases where water would attack the pipes. With leaden
pipes, however, a poisonous dose could be present in the water
without its being detected by the taste. There was, therefore,
in his opinion, only benefit to be deri\ ed from the substitution
of copper for leaden pipes for the supply of water to houses.

The report of Professor Gautier. the chief points of which
are summarised above, is published in the current issue of
Biologica (1911, VI, 79). His conchisions agree with those
of the American chemists and doctors who have advocated
the use of copper sulphate and metallic copper for the
sterilisation of drinking water. Readers of these columns
will also remember that copper sulphate is now used upon a
large scale in America for destroying the pond scum upon the
water reservoirs.

GRECIAN BLACK ENAMEL.— The rich black lustre
upon Grecian and Roman pottery has long been attributed to
the presence of manganese, but according to M. L. Franchet,
who has recently studied the question \Coniptcs Rcndiis,
1191, CLII, 1097), the proportion of manganese is altogether
insufficient to produce the effect upon the ancient vases. The
suggestion made by Verneuil that the (jreeks made use of
metallic iron obtained by the reduction of an oxide, is not
in accord with the statements of ancient writers, who assert
that natural products were employed.

Since the mineral magnetite was known to the Romans,
who obtained it from Piedmont, M. Franchet has made

31 S

KNOWLEDGE.

August, 1911.

experiments with tliat natural ferroso- ferric oxide, and. by-
fusing it in an oxidising flame witli quartz sand and sodium,
lias succeeded in reproducing the black enamel.

The richness of the lustre is probably increased by the
presence of a trace of manganese in the magnetite. A similar
enamel is found upon the Egyptian pottery, and it is probably
trom Egypt that the GreeUs derived their knowledge of the art.

PROPERTIES OF .A.LUNDUM.— .A fused form of
alumina is now extensively used under the name of
" .-Mundum " in the manufacture of crucibles and other \essels
for which a refractory material is needed. .According to
Mr. L. E. Saunders iAiiici: ElcctrocJiciii. Soc. .'\pril. 19ll),
the commercial product is usually a white crystalline
substance containing less than one per cent, of iron oxide and
other impurities. There is also a red-brown variety contain-
ing about five to six per cent, of impurities, and melting at
about 2,000 to 2.050° C. or about 50° lower than the white
alundum. The specific gravity of the latter is 3-93 to 4-00,
and its heat conductivity is from three to four times as great
as that of fire clay. It resists the action of aqueous acids
and alkalies and is only slightly attacked by fused alkali
carbonates. Crucibles of alundum may be used for melting
metals with as high a melting point as platinum, though they
are too porous to be used for melting slags. .\ cement for
lining furnaces is also prepared from alundum. and has the
advantage of not melting or combining with carbon at
temperatures below 1,950 C. Bricks of alundum have also
been used instead of silica for the roofs of electric furnaces.

THE TR.ANSFORM.ATION OF R.\DIL'M.— Professor
Rutherford, to whom w^e owe much of our knowlege of radio-
active bodies, gives a most interesting survey in the Journal
of the Society of Chemical I ndiistry i\9\\. XXX, 659), of
the principal results regarded from the chemical point of view.
'l"he three types of rays emitted by radio-active substances are
classified as a. ii, and 7 rays in accordance with their pene-
trative capacity and effect upon a magnetic field. The a rays
possess only slight penetrati\e properties, and are readily
stopped by a metal plate. They appear to consist of streams
of particles identical with the gas helium. The ji rays are
more penetrating and more easily deflected by a magnetic
field, and are supposed to be identical with electrons ; while
the 7 rays are exceedingly penetrating, are not deflected by a
magnetic field, and ha\e apparently properties analagous to
those of the Rontgen rays.

Uranium is to be regarded as the first parent of the radium
family. It is decomposed so slowly that about five thousand
years would be required for half of it to be transformed
into an element termed Uranium X, with an atomic weight of
230-5. This emits ,i rays, and is transformed into ionium,
the direct ancestor of radium. Coming to radium itself, a
continuous disruption takes place with the liberation of
a rays (helium) and the formation of a new element, the
radium emanation, which appears to be one of the inert
gases. This radium emanation, in turn, breaks up with the
expulsion of an a particle or helium atom and the formation
of a new very unstable element. Radium A, which is rapidly
transformed into another metallic element. Radium B, decom-
posing in twenty-six minutes, with the expulsion of ;i ravs, into
Radium C. The latter breaks up into Radium D, which in turn
yields ;uccessi\ely Radium E and Radium F. The element
polonium has been identified with Radium F, and there is some
evidence that the element formed in the decomposition of
polonium is lead. The atomic weights and the nature of the
radiations emitted by these successive elements are summarised
by Professor Rutherford in the following table : —

Radial ion. .Aloinic Weight.

Uranium... ... ... 2a ... ... 238-5

Uranium X ... ... .i ... ... 230-5

Ionium ... ..■. ... la ... ... 230-5

Radium ... ... ... la ... ... 226-5

Emanation ... ... la ... ... 222-5

Radium .\ ... ... la ... ... 218-5

Radium B ... ... )i ... ... 214-5

Radiatinn. Atomic Weight.

Radium C ... ... fa ... ... 214-5

Radium D -i 210-5

Radium E ,i 210-5

Radium F la 210-5

End product — 206-5

(lead?)
Many interesting details are given of the methods of
examination employed in the investigation of these bodies,
but, as Professor Rutherford points out, " the process of
transformation cannot be influenced to the slightest degree
by any chemical or physical agency. \\'e are only able to
watch these atomic processes, but cannot control them."

GEOLOGY.

By G. W. TvKRK[,i,. A.R.C.Sc. F.G.S.

THE PROBLEM OF THE SCOTTISH HIGHL.\Ni)S.
— .A. new interpretation of this classic region is put forward by
Professor J. W. Gregorv, in the Transactions of tlic Glasgo'^-
Geological Society, Vol. XIV (1910).. The most disputed
points are the age of the Ualradian System, and which is the
top or bottom of its long succession of deposits. In regard to
the first question. Professor Gregory believes the Dalradians
to rest unconformably upon the Moine Gneiss, an extensive
flaggy formation which stretches from the Central Highlands
to the Pentland Firth ; but from certain evidence in Islay, they
are probabl>- older than the Torridon Sandstone. Among the
Dalradians themselves, the Loch Lomond Gneiss is believed
to be the oldest. This is succeeded to the north by the Loch
Tay, Ben Lawers. and Blair .\tholl series, and the Schichallion
Quartzite, .AH these rest unconformably upon the Moine
Gneiss to the north and north-west, with the exception of the
Loch Lomond Gneiss, which does not appear to come into
contact with the Moine anywhere. Two further series, the
Ben Ledi and the .Aberfoyle, occur to the south of the Loch
Lomond Gneiss, and appear to rest unconformably upon that
formation. The great band of quartzite in the Central
Highlands is, under this arrangement, the j'oungest rock in
the Dalradian System, with the possible exception of the
.Aberfoyle Series. It rests unconformably upon the black
schists of the Blair .Atholl Series, and forms great cakes which
have been carved into bold mountain masses such as
Schichallion and Ben-y-ghlo. Two other horizons of quartzite
or quartz-schist occur below the Schichallion quartzite. These
separate groups have often been confounded together, and
also with some portions of the Moine Gneiss, but they can
usually be distinguished by their petrographical characters, as
well as by their stratigraphical position. Professor Gregory
concludes his paper with a series of suggestions as to useful
research by Glasgow geologists on the south-western
Highlands.

NEW MEMOIRS OF THE GEOLOGICAL SURVEY
OF SCOTL.AND — The three interesting memoirs on Edin-
burgh, East Lothian, and the Glenelg district, recently issued
by the Scottish Geological Survey, form %ery important
additions to our knowledge of Scottish geology. The first two
are new editions, but they are entirely new works, and their
superiority to the first editions, issued forty or fifty years ago,
is a measure of the advance in local geology during that period.
The Edinburgh memoir is a volume of 445 pages, and contains
numerous beautiful plates, as well as a geological map of
.Arthur's Seat, This classic hill, vvhich renders the local
geology as picturesque as Edinburgh itself, is fully described,
and the description, together with the geolo.gical map, has
been issued as a separate pamphlet at the price of sixpence.
The oil-shale field of Central Scotland comes within the area
described in this memoir. This industry has been developed
since the issue of the first edition, and the new information
made available by mining operations has rendered necessary
great changes in the geology of the region.

The East Lothian Memoir describes rocks ranging from the
Silurian of the southern uplands to the Coal measures disap-
pearing under the Firth of Forth. The district includes the

August, 1911.

KNOWLEDGE.

319

interesting area of the Garlton Hills, made up mainly of
trachytes, with some mugearites and basalts, and an occurrence
of the rare kulaite (hornblende-basalt), all lavas of Calciferous
Sandstone age.

A little-known and rather inaccessible, but beautiful, region
is described in the memoir on "The Geology of Glenelg,
Lochalsh and the south-east part of Skye." The geology is
extraordinarily complex, as the area contains the southern
ends of some of the great thrust-planes which are a feature of
the north-west of Scotland. The relation of the iMoine to the
Lewisian gneiss is well displayed. The Moine is shown to
rest unconformably on the Lewisian. with a basal conglomerate
at some localities. Variety is given to the geology of the
district by the inclusion of a portion of the Tertiary % olcanic
rocks of Skye, and of a series of highly fossiliferous Mesozoic
strata, ranging from the Trias to the Upper Cretaceous.

The maps issued with these memoirs are colour-printed, and
are the first Scottish maps to be so issued. They are a^reat
improvement on the expensive and somewhat unreliable hand-
coloured maps.

METEOROLOGY.

Ky JoH.v .A. Curtis. K.K.Mkt.Soc.

The weather of the week ended June 17th. as indicated by the
Weekly Weather Reports issued by the Meteorological Office,
was at first fair and dry in the South and West, but cool and
showery in the North and East. Towards the end of the week
rain set in very generally, and thunderstorms were experienced
in many places.

Temperature was below the average in all districts except
the English Channel, where it was 0-2 above. The greatest
difference from average was in Scotland E., where the mean
was 4 ■ 5 lower than the normal. The highest reading recorded
was 76° at Killarney on the 11th, which was S'-O lower than
the maximum of the previous week. .At many stations the
maximum did not reach 70°, and in the extreme North it was
under 60 , only 54° at Lerwick, The minima ranged down to
28" at Balmoral and 30° at Llangammarch Wells. In the
English Channel, however, the minimum did not fall below
• 46". On the grass very low readings were recorded, 19° at
Llangammarch Wells, 24° at Birmingham, and 26' at several
stations.

Rainfall was generally deficient in the eastern parts of the
country, and in Ireland N., but was in excess elsewhere,
though not to any great extent. Sunshine was above the
average in all districts and at nearly every station. The
sunniest stations were Rhyl 76-4 hours (66%!, and Jersey
70-3 hours (63''o). .At Westminster 50 -S hours (45%) were
recorded, while at Glasgow only 35-7 hours (30%) were
registered. The temperature of the sea water round the
coasts varied from 49° at Lerwick and Pennan Bay. to 62 ' at
Seafield.

The weather of the week ended June 24th, Coronation week,
was generally cool and cloudy, though in the first part of the
week there were fairly long sunny intervals. Thunderstorms
were experiencd on Sunday and Monday. Temperature was
normal in England N.W., below it in Scotland W., England
S.W. and S.E., Ireland and the English Channel, but above it
elsewhere, the variations from the normal being, however, but
slight. The highest temperatures recorded were 74° at
Greenwich on the 23rd, and 73° at Bawtry on the 22nd. .At
many stations the maximum was below 70°; the lowest readings
were nowhere so low as in the previous week, and no reading
below 40' was recorded. In London the minimum was 52°.
and no ground frost was reported.

Rainfall was in excess everywhere and some very heavy
falls were reported. .At Shields and at Alnwick Castle the
amounts exceeded 4-0 inches, which is more than eight times
the usual quantity. -At Westminster the total was 1-12 inches
on five days. At Bath, though rain fell on each day of the
week, the total collected was only 0-58 inches.

The district values of bright sunshine ranged from twenty-
six hours (22%) in England N.W., to forty-four hours (39%)
in the English Channel, Strangely enough, the two sunniest

places were at the extreme North and South of our Islands,
Stornowav reporting 49-1 hours (39%) and Guernsey having
49-6 hours (44%). At Stonyhurst only 11-2 hours (10%)
were recorded. The temperature of the sea water varied
from 48° at Berwick to 62' at Margate.

The week ended July 1st, was unsettled and rainy, with
occasional thunder and lightning. Temperature was below
the normal in all districts, by as much as 4" -4 in Scotland. W.
The highest reading reported was 73° at York, Clacton, Raunds,
Yarmouth and Tottenham. In Jersey, howe\'er, the maxinniin
was only 63". The lowest readings were 37" at Kilmarnock
and 39° at Cally and at West Linton. In Westminster the
extremes were 72' and 50'. C;n the ground the temperature
fell to 27° at Llangammarch Wells, and to 31° at .Armagh.
Rainfall varied a good deal, but the departures from the mean
were nowhere so severe as in the previous week. In Scotland
N., the fall was about half as much again as usual, but in
Ireland it was only one half the usual amount. Bright
sunshine was in defect in all districts, the deficiency reaching
20% in the English Channel. Falmouth had the highest
record for the week, 45-6 hours (40?/ol, while at Weymouth
43-5 hours (39%) were recorded. Westminster had 26-6
hours ^25%). The temperature of the sea water varied from
49° at Ballintrae to 63° at the Shipwash light vessel off the
East Coast.

The week ended July Sth, began with unsettled rainy weather
over Scotland and Ireland N., but with very fine weather in
all other parts. By the end of the week the fine weather had
extended to the Northern districts also. The average tempera-
ture was above the normal in most districts, though not
markedly so. The individual readings, however, were
exceptional and exceeded 80° in all parts except Scotland N.
and W., and Ireland N. The highest readings recorded were
90-" at Cullompton in North Devon, on the Sth, and 88° at
Greenwich, Oxford, Raunds and Wisley. The minima were
as low as 36° at Balmoral, and 37 ' at West Linton and Fort
.Augustus, but as a rule the lowest readings ranged between
40° and 50°, and were in some cases over 50°. Slight frost on
the grass was experienced at Crathes (30°t and at Llangam-
march Wells (29°). but in most places the grass minimum was
above 35°. Rainfall was slightly abo\e the average in
Scotland N., but was in defect in all other parts of the
country. At many stations no rain was experienced through-
out the week. .At Westminster the total was 0-01 inch,
while at Greenwich there was no rain. Bright sunshine was
in excess in all districts except Ireland N.. where it was very
slightly in defect. The English Channel was the sunniest
district with 93 hours (83%), but the most sunny station was
Hastings, 97-5 hours (86%), In contrast whh this was the
North-west of Scotland, where Glasgow reported 27-5 hours
(23%), and Fort .Augustus only 20-9 hours 117%). The tem-
perature of the sea water ranged from 48° at Lerwick to 65°
at Margate and Eastbourne.

The week ended July 15th was exceptionally fine and dry
throughout. Temperature was above the average in all
districts, by as much as6°-0 in Ireland, S. The highest read-
ings were 89° at Crieff, and 88° at Balmoral, Cullompton and
in Ireland. S. The minima varied greatly. In the English
Channel the lowest reading was 5-f- at Scilly, giving a range of
temperature for the week at this station of 21°, while at West
Linton the minimum was 35° and the range for the week 49°.
.At Durham. .Alnwick and Llangammarch readings of 36° were
recorded. On the grass still lower temperatures were observed,
the lowest being 23° at Llangannnarch and 29° at Crathes.

The rainfall w^as unusually slight : indeed over the greater
part of the kingdom the week was rainless. The largest
amounts reported were 0-35 inches at Gordon Castle, and
0-38 at Glencarron. Bright sunshine was greatly in excess
in all districts, and at many stations it was double the usual
amount. The sunniest stations were Newton Rigg, 100-4
hours (86%), Aspatria 100-2 hours (86%), and Bournemouth
99-9 hours (89%). .At many other stations the total duration
of sunshine exceeded 90 hours. Over the country generally
the week was the finest experienced since the general establish-
ment of sunshine recorders, in 1881.

320

KNOWLEDGE.

August, 1911.

The temperature of the sea was higher than in the corres-
ponding week of 1910, and the individual readings varied from
52° in Scotland to 67" at Margate, and 70' at Seafield.

During a kite ascent from Pyrton Hill on June 14th. the
sky was o\ercast, but though the kite ascended to a height of
over four thousand feet, the clouds were not reached. On
this occasion the direction of the wind was found to be the
same throughout, but its \elocity steadily increased with the
altitude. The humidity of the air also increased with the
height from 70% at the ground to 95"o at four thousand feet,

MICROSCOPY,

By A. \X. SHEPP.iRD. F.K.M.S..

witli tlic assistance of flic foUoiciiiii tiiicroscopists : —

.Arthur C. Banfield. Arthur Earland. F.R.iM.S.

The Rev. E. \V. Bowell. iM..A. Richard T. Lewis. F.R.M.S.

Ja.mes Burton. Chas, V. Rolsselet. P^.R.M.S

Charles H. Cakfyn. D. J. Scourfield, F.Z.S., F.R.M.S.

C. D. Soar, F.I...S., F.R.M..S.

HVDRACAKINA OF CLARE ISLAND.— The Royal
Irish Academy has just published part 39i of the Clare Island
survey. This paper, to any one interested in the Hydracarina
of the British area, will prove most valuable. The results of
the survey will be published from time to time, as the different
experts who have undertaken to work at their own particular
group finish their reports. These reports will not only
contain the flora and fauna of the island, but the history and
geology of the district, and will be published in sixty-seven
parts, four' only of which are ready, Mr, J, N, Halbert, of
the National Museum, Dublin, undertook, and has finished, the
Hydracarina, and he has done it well. It is. I think, the best
paper yet published on the water mites of the British area,
both as regards the te.\t and the figures. Mr, Halbert has
added four new species to science : Eylais rclicta,
Frontipoda Carpeiiferi, Atractldcs brcvirostris and
L'tiionicola riiuilaris. Besides the above he has also added
twelve species previously recorded on the continent only,
-Altogether, Mr, Halbert records eighty species, representing
thirty-one genera, which, with the sixteen additional ones now
added by Mr, Halbert, gives us two hundred and thirty species
of Hydracarina, representing sixty-one genera, for the British
area, Hydrysphantcs placationis K, Thou, which Mr.
Halbert asterisks as a new record, has been already recorded
by Mr, W, Evans in 1909, for Scotland. See Proceedings
of the Royal Physical Society of Edinburgh, \'ol. XVH,
page 42.

There is one mite Mr. Halbert mentions «hich I am not
sure is correctly named on pa,ge 37 ; he mentions Arrhenurus
triciispidator, O. F, Miill,, Achill Island. June. "The mite
recorded here is the A. bicuspidator (Koenike) 12. and other
references." Now Koenike, in 12, Acarina Milben Brauer,
Die Siisswasscrfauna Deiitschlands, Heft, XII, 13-191,
Figure 1, 277. 1909, gives both .4. tricuspidator Miill. and
.-1. bicuspidator Berlese, and there is no mistaking the two
mites. The petiole of Miiller's Figure Plate iii. Figure 2, in
his Hydrachnae, 1781, is certainly rounded on the extreme
posterior margin, but in Berlese's -4. bicuspidator the margin
of the petiole is curved inwards. I have both mites myself.
What I take to be the real .4, tricuspidator Miill, was
recorded by Dr. George, for Britain, in 1901, as ,4. niaxiinns
Piersig, Science Gossip, 1901, page 230.

One of the most interesting finds is Frontipoda
carpentcri Halb, as previous to this we only knew one
species of this genus, F. niusculus Miill. Another is the
addition to the genus Atractides. Mr. Halbert gives a very
useful synoptical table for the determination of species.
There are three plates of well-drawn and well-produced
figures, giving the absolutely essential details for identification
of the species. Take it all round it is a most interesting
addition to the l^ibliographv of fresh-water mites,

Chas, D, Soar, F.L.S., F.R.M.S.

HYDRCRUS FOETIDUS VILL.— Recently I had the
good fortune to come across the above, and as it is in sexeral
respects a singular and interesting plant, it may be worth

while bringing it forward in a short note. The first point
about it is that it is decidedly rare in this country. Professor
West says, "It is of very rare occurrence in the British
Islands, being known only from Yorkshire and Scotland," But
" it is common in central Europe and in the Arctic regions
when the snows melt in spring," I found it in great abund-
ance in a coinparati\ely quiet backwater, in a rapid stream of
ice-cold water rnnuing down towards the Mer de Glace, at
Chamonix. It was attached to the rocks and stones, and was
plentiful on a rock forming the edge of a small cascade. To
the naked eye it looks like a dull-coloured moss, or
one of the filamentous algae ; the filaments attached at
the base, floating free and swaying in the stream. Its
specific name foctidus is appropriate, as it has a most
unpleasant smell, resembling that of stale fish. The
" Micrographic Dictionary" styles it "a genus of Confervoid
algae " but at the same time points out its obviously
true relationship, which is with the very simplest of
the algae, the Palmellaceae, Probably there is not more
than one species. Professor West calls it Hy drums foetid us ;
Cooke, H. penicellatus, and mentions a variety. The fila-
ments vary in size from quite small ones, up to a length of
several inches. They are of considerable thickness, and
simple at the base, while above they are densely branched, the
branches often thickly covered with minute outgrowths and
fibres, giving the whole a very moss-like appearance. Dr.
Cooke has a drawing — " British Freshwater Algae," Plate 10
Figure 4 — which exaggerates this a good deal, unless his
illustration was taken from another variety. One would
naturally expect the stem and branches to consist of cells with
definite walls like other plants, but they do not. The whole is
formed of a more or less tough gelatinous sticky substance,
without any apparent structure under the microscope, and in Ihis
are embedded numerous minute olive-green bodies. They are
packed closely and are somewhat globose in the branches, with a
tendency to become mis-shapen and angular owing to pressure,
while in the stem they become oval and elongated, or even
comma-shaped, and are arranged partially in lines. They do
not seem to have a definite wall ; Dr. Cooke says it is difficult
to distinguish one ; Professor West says there is none. It is
of course, these very small bodies that give rise to the
gelatinous moss-like structure, and except for the peculiar
form — a chance resemblance to that of a much more highly-
developed organism — the relationship to such plants as
Tetraspora. Sphaerocystis andPalniodictyon, which we find
constantly in our own waters, would be evident. Professor
West tells us " the entire structure behaves almost as a
multicellular plant, growth in length being entirely dependent
on single apical cells." He classes it with the Phaeophyceae,
but its affinities seem to me much more with the simple
genera named above, than with the highly-developed and
specialised brown sea-w-eeds. Reproduction takes place by
means of peculiar-shaped zoogonidia, developed from the
colom'ed bodies in the branches. The filamentous form and
minute branches and fibres are probably only an adaptation to
the circumstances under which the plant exists. Were it not
attached firmly to the rocks and stones, and of a form which
gives only slight resistance to the stream, it would soon be
washed away in the rapid torrents in which it dwells. Cold
and violent mountain streams are not favourable dwelling
places for most Algae ; it is hardly worth while looking for
them there, and this e.xample is remarkable on that account as

well as for its singular structure.

J. B.

THE MICROLOGIST.— We have received from .Messrs.
Flatters. Milborne and McKechnie, Ltd., the July number
(Part v.), of their little iiuarterly journal. Tlie Micrologist.
As usual it is well illustrated, there being twehe text figures
and three plates of figures reproduced in half tone. The first
article is by Mr. Gordon A. McKechnie, and is devoted to the
Porifera (spongesl. A short account is given of their structure,
classification and life-history, which is followed by details for
the preparation of slides illustrating the histology of the
different types. The slides, six in number, sent out with this
part all illustrate sponge structure. Transverse sections of
Grantia conipressa, Euspongiii officinalis. Hiilichcinilnu

Al'GUST, 1911.

KNOWLEDGE.

321

panacea. Gcodia gigas. Spoiigilla laciisfris. and the entire
sponge (young) of Lcitcosolcnia hotryoidcs : this last slide
shows the budding of a sponge. The section of Granfia
coinpycssa exhibits the collar-cells [choanocytcs) ; the fresh-
water sponge (S. lacitstris) shows the "gemmules," vide
page 59. The three plates referred to above illustrate Mr.
Abraham Flatters' paper, which is devoted to the preparation
of slides illustrating the histologv of the wheat plant.

THE DWARF PLANKTON.— In connection with the
short report in " Knowledge" (June, page 236) of my paper
on '■ The Use of the Centrifuge in Pond-Life Work," read
before the Quekett Microscopical Club in April last, I should
like to call attention to a little pamphlet recently published
by Professor H. Lohmann. of Kiel, entitled, " L'eber das
N'annoplankton und die zentrifugierung kleinster Wasserproben
y.nv Gewinnung desselben in lebendem zustande " iW.
Klinkhardt, Leipzig, M. 1'50). The term Nannoplankton
(I'dj'i'os = dwarf) has been coined by Lohmann for the
e.xtremely minute forms of life existing in water, the
forms, in fact, which pass easily through the meshes
of the finest silk gauze, and his paper is in the main a
summary of the additional knowledge which has been gained
about these organisms by the use of the centrifuge. The
application of this instrument to the special purpose of
collecting these very minute organisms is due to Lohmann,
who was led to the conclusion that something supplemental to
nets, or even filter papers was wanted as a means of collecting
the smaller constituents of the plankton, by observing
the rich and varied accumulations of tiny protists
obtained by the extraordinarily line filtering apparatus
of some marine animals such as the Appendicularia.
The method of centrifuging water in order to con-
centrate the contained " Nannoplankton " is undoubtedly
a very powerful new means of research, and it can no longer
be ignored by those interested in the life of our seas and
fresh-waters. Very small quantities of water are sufficient as
a rule (1 often work with tubes holding onl\- one-and-a-half
cubic centimetres! and the bulk of the forms present are
deposited in one or two minutes if the centrifuge be run at a
fairly high speed, say two thousand to six thousand revolutions
per minute. Practically no damage is done to the organisms
during the process of centrifuging, and if examined immediately
after, they will be found to be alive, so that even the most
sensitive and fragile of the naked forms can be recognised.
This, it need hardly be pointed out, is an utter impossibility
with collections made by any straining method yet invented.
The Nannoplankton is composed of bacteria, protophytes
(schizophyceae, desmids, diatoms, chlorophyceae, phyto-
flagellates), and protozoa (rhizopods and zooflagellates).
the bulk being usually formed by the phytotlagellates.
The comparative volume of the Nannoplankton is small,
but as Lohmann points out this does not prove that it is
of no importance in the economy of the sea and fresh-waters.
" The degree of importance in this respect depends essentially
on the rapidity of the multiplication and the duration of life-
time, as well as on the nutritive character of the organisms
themselves. In this latter direction the Nannoplankton
surpasses perhaps all the other Plankton and in the former
respect it equals the other Protists at least. Should one wish
to estimate the importance of the three chief groups of
Plankton only according to their average life-time, one must
place on a par one volume of Bacteria to about six volumes of
Protists and to about three hundred volumes of Metazoa."
For those who cannot read German there is an English
summary appended to the paper, which is also accompanied
by five plates of Nannoplankton organisms, drawn to scale, in
frames representing a single opening in the silk gauze used for
the finest Plankton nets.

D. J. ScouRFiELD, F.Z.S., F.R.M.S.

QUEKETT MICROSCOPICAL CLUB.— June 27th. 1911,
Mr. C. F. Rousselet, F.R.M.S., Vice-President, in the chair.
Mr. J. W. Ogilvy exhibited for Messrs. Leitz a recent
invention, on the principle of the dark-ground illuminator, for
rendering visible the particles in smoke and gases, and in

liquids. Messrs. Watson exhibited a series of seven prepara-
tions, illustrating the development of the chick. The stages
were twenty-four, thirty-two. forty, forty-eight, sixty, seventy-
two and ninety-six hours of incubation.

A paper by Dr. E. Penard. on " Some Rhizopods from
Sierra Leone " was read by Mr. Earland. The material
examined was collected from a " slow, large river, containing
weeds." Fourteen species had been found, of which three
were new. and four at least might be considered as special
forms or varieties. The genera represented were : —
Ceiitropyxis, two species; Difflugia. five species (two new) ;
Englypha. two species ; Lcsqucrcntia, three species (one
newl ; and Pontigtilatia, two species. The author expressed
his indebtedness to Mr. G. H. Wailes for the material received
and hoped that time and opportunity would be found for
further investigations.

Mr. T. A. O'Donohoe read a note on " Dimorphism in the
Spermatozoa of the Flea and the Blow Fly." Only about
70% of the specimens examined had the two forms noted, the
minority having only the smaller form. The spermatozoa of
the flea are very large compared with those of man, whose
spermatozoa have an average length of about 0 • 06 millimetres.
In the flea the larger form is 0-7 to 0-45 millimetres long,
and the smaller form about half these lengths. Both are
similar in structure and stain well with dilute carbol-fuchsin
or gentian-violet. The two forms found in the Blow Fly are
smaller than those of the flea. They do not differ much from
each other in length, but one is very much thicker than the
other. Photomicrographs of the specimens described were
projected on the screen.

A paper by Mr. E. M. Nelson, F.R.M.S., on " Normal and
Abnormal Vision in Microscopic work," was read by the
Assistant Honorary Secretary. The experiments described
showed the effects of long and short sight upon the magnifying
power of the microscope. The differences are most marked
with low powers. The author's sight being presbyopic,
biconvex glasses are required to make it normal. When
ineasm'ing the pow-er of a microscope by means of a camera
lucida, it is therefore necessary to use spectacles, otherwise,
while the image of the micrometer in the microscope is sharp,
that of the exterior scale, at ten inches distance, would be
invisible to him. Experiment 1. — The power of a '" loup "
(focus about 1-6 inch) was measured, the spectacle lens being
below the camera. The power was 6. Experiment 2. — As
before, but with the spectacle lens above the camera ; the
power was 7. Experiment 3. — .A double pair of spectacles of
equal power were used ; the presbyopic eye was therefore made
myopic. A conca\e lens, which precisely neutralised one of
the spectacles lenses, was placed below the camera. The
■' loup " now ga\'e power 8. Experiment 2 shows the power'
of the " loup " with normal sight. The experiments on being
repeated with a compound microscope giving six diameters
showed similar results. It is generally understood that
persons with short sight have wonderful pow-ers of seeing
minute objects, but few realize that anyone with three
dioptres of myopia can with a six-power " loup " see as much
as one having three dioptres of presbyopia with an eight-
power " loup." Further experiments were also described.

ROYAL MICROSCOPICAL SOCIETY.- June 2Sth— Mr.
H. L. Plimmer, F.R.S.. President, in the chair. — Mr. Strachan :
The structure of scales from Thcnuobia doinestica Packard.
The author showed that the longitudinal striae which appeared
to project at the free margin of the scale were in reality the
walls of a set of longitudinal tubes, and when pressure was
applied to the scales the tubes might be made to collapse and
disappear, and in some instances, when heat was applied, both
fluid and air bubbles were observed to traverse the tubes.
These tubes were on the convex side of the scales. Radial
striae also crossed the longitudinal striae at various angles,
and the author illustrated his paper by an ingenious model
composed of two sets of parallel thin glass tubes in close
contact, almost filled with fluid and sealed at the ends, one set
containing oil of turpentine, the other ethyl alcohol. One set
of tubes was fixed ; the other set, placed in contact with them,
could be rotated over a considerable angle. By illuminating

322

KNOWLEDGE.

August, 1911.

this model obliquely and varying the angle at which the tubes
crossed, all the appearances of beaded, exclamation and
cuneate markings observed in the natural scales could be
exactly reproduced. — Mr. Murray: Further report on the
rotifera collected by the ShacUleton Antarctic Expedition of
1909. Rotifera of Nezc Zealand. There were collected
forty-one species of Bdelloids, and twenty-six species of other
orders. Three new species were described — CaUidina
iiiicrocornis, Rotifer ciirtipes and R. inoiitaiuis. A species
of Pedalion (not ideutilicdl occurred as a plankton animal in
a great lake tWakatipuL The Bdelloid fauna of New Zealand
appeared to be poor, considering the variety of conditions
found in different regions. Rotifera of S. Africa. During a
short stay at Cape Town nine Bdelloids were collected on the
lower part of Table Mountain. There was one new species.
Dissotroclta pcctinata. related to D. spinosa. This small
collection was noticeable for the absence of any of the species
characteristic of tropical and subtropical Africa, many of
which occurred in other parts of Cape Colony.

Mr. Conrad Beck gave a demonstration of the method of
determining in wave-lengths the divisions of a stage-
micrometer by means of an interferometer.

He said the interferometer consists of a series of mirrors
which receive a beam of light from a radiant somxe, and divide
it into two beams of light, which are afterwards re-combined
and viewed by a telescope. All the portions of the instrument
are fixed, except one reflecting mirror, which reflects one-half
of the divided beam of light. This can be set in such a
position that the two half-beams of light, during their period
of division and before they re-combined into one, ha\e
travelled exactly the same distance. .A movement of the
reflecting mirror can then be made, so that one half -beam of light
has travelled half a wave-length farther than the other ; and
when that is the case, interference will take place, and the
light will be extinguished. As the mirror is moved farther, the
light will again appear, until the path is one-and-a-half
wave-lengths different, when a second interference is produced :
this goes on at each successive motion of the mirror through the
same distance, and the wave-lengths are counted.

As a matter of practice, it will be seen, on looking through
the telescope, that the effect is not a complete change from
brightness to darkness, because this only takes place in the
exact centre of the field, and a series of bright and dark
bands are seen in the field, which travel from right to left,
and are counted as they cross the centre of the field against a
line in the telescope.

The apparatus was shown with a Bunsen burner and a
sodium flame as being a sufficiently monochromatic light
for demonstration ; but as the sodium light is not a purely
monochromatic light, but consists of two lines which are not
in themselves quite monochromatic, sodium does not form a
very good source for the illumination. Either cadmium,
mercury or hydrogen, used in connexion with a prism which
shall direct one only of the chief lines into the instrument, is
the best for the purpose.

The micrometer is held on a bracket which projects out
from the carriage on which the moving mirror is l^xed in such
a manner that, although it is \ iewcd by the microscope, it is
not in contact with it, and no friction is caused which could
interfere with its motion.

Mr. Conrad Beck exhibited a new portable microscope
suggested by Mr. Murray. He said that this instrument had
been designed to meet the wishes of Mr. James Murray, the
well-known explorer, who was anxious to have a microscope
extremely small and portable, and which could be used in the
field. Being away from the comforts of civilization, in
tropical forests, he would be debarred from the luxury of
chairs and tables, and the microscope was therefore so
designed that it had one leg. which could be strapped to a
walking-stick, which had been driven into the ground, and the
observer could sit with the stick projecting from the ground
between his legs, and the microscope could be inclined
by means of the usual joint to a convenient position.
The instrument was on the model of the Star Microscope,
with an aluminium stage, and all the superfluous metal
removed to make it extra light. It had a sliding coarse-

adjustment, a micrometer-screw fine-adjustment, and a small
substage condenser, with iris diaphragm. It was provided
with two loose legs, which screwed into the single leg-base,
making it into a tripod for use on a table in the usual way,
when such a support was available on the return from an
expedition. I'or the study of pond-life on the spot this instru-
ment was especially desirable, as the naturalist on the walking-
ing-stick-stand principle might spend many profitable hours in
pleasant weather in conducting his microscopical examination
at the side of the pond, or on the country-side in the open air.
Mr. Murray remarked that as the journey he was about to
undertake had to be made without the assistance of carriers,
it became important to reduce the weight to the utmost,
because every ounce put into instruments to be taken must
be deducted from the amount of food which could be carried.
Therefore, remembering his previous experience with the Star
Microscope on his journeys, he asked Mr. Beck if he could
improve upon that instrument in the matter of weight. The
present microscope was the result. It was true that the
necessity for unscrewing the legs of the tripod introduced a
structural weakness, but the instrument was intended to be
primarily used on a walking stick. Its use in the ordinary
way. on a table, was a secondary matter. It was not antici-
pated that one would be able, as Mr. Beck had said, to sit
comfortably and work with the microscope ; that was usually
impossible in the Amazonian forest. It was proposed to have
the walking-stick sufficiently long to enable the observer to
work standing. Quite possibly the conditions would prevent
work, but it was hoped sometimes to rig up a net to keep out
insects and allow a little work to be done. Mr. Beck had not
stated what the weight of the microscope was. Complete in its
case, as fitted for use on the table, it weighed two pounds.
But even that was far too much to take on such a journev ; for,
as he had said, only so much could be taken, and the heavier
the instruments, the less the quantity of food which could be
carried. Therefore, when the difficult journey began, the
case of the microscope would be left behind, the two supple-
mentary legs would be unscrewed, and the microscope folded
up and wrapped in a spare shirt. The weight, without the
case, was only one pound.

HOrRVDIi-M GRAXUL.ATVM iL.I— The water at the
Welsh Harp reservoir, Hendon, is very low, and it may be of
interest to some to know that large stretches of mud are at
present — July 20th — in many places covered with the singular
little plant Botrydinin grainilatnni. It is not so plentiful
as it was last year, vide Journal of the Ouckett Micro-
scopical Club, Ser. 2, Vol. XL, No. 68, page 209, probably
because, with the drought and great heat, the mud is dried too
quickly for the plant to develop. Botrydiiini does not seem
\ery common in the London district, but here it covers an
immense area.

J. B.

ORNITHOLOGY.

By Hugh Boyh Watt. M.B.O.U.

DISTRIBL' rioN OF TH1-: NKiHTlNGALE IN
GREAT BRITAIN— FIRST OCCURRENCE IN SCOT-
L.-\ND. — Connnenting on the note in our last number (page
282) a correspondent writes as follows: — "It appears to me
that the whole body of evidence collected by Messrs. Ticehnrst
and Jourdain wants to be rearranged with respect to its salient
features; restated to show the value or valuelessness of its
component parts ; and, generally, to be dealt with in as broad,
critical, and philosophical a spirit as can be brought to bear
upon it. I am pleased that the information has been brought
together; more than that I cannot say. unless that I am
dissatisfied with the want of any adecjuate examination of it
by the authors of the paper."

Our correspondent (who writes from Scotland) further
remarks that the physical difticulty of extension was overcome
when the Nightingale had reached the valleys of the Dee,
Weaver, and Mersey in Cheshire, and that there was
consequently nothing physical to prevent extension into
Lancashire ; also that if the species had been in Yorkshire

August, IQll.

KNOWLEDGE.

323

and Lincolnshire for a century there was nothing to hinder it
following the coast line to Scotland.

These observations have received immediate point by tlie
publication in the new lumiber of the Annals of Scottish
Xiitiiral History l.\o. 79. July. 1911, page 1321 of a short
paper by Misses E. \'. Baxter and L. J. Rintoul announcing
that thev had secured a single specimen of the Nightingale on
the Isle of May, Firth of Forth, on 9th May, 1911. This is an
addition to the avi-fauna of Scotland, and to the rarities and
valuable records which careful and continuous watching of
the Isle of May has yielded to the writers .above-named.
Following recent nomenclature they call the bird the Southern
Nightingale [Liiscinia mcgarhynchos nicgarliynclios =
Daiilicis tiiscinia of Saunders and other authors!.

^Our readers are invited to send in any observations that
they may be able to make upon the distribution of the
Nightingale.]

XKE BLACK GAME VERMIN ?— The answer to this
question, like many others, depends largely upon the point of
view and upon personal predilections, and sportsmen may
probably not agree with the judgment given in the recently
pubhshed " Forest Survey of Glen Mor " (1911), by Lord Lovat
and Captain Stirling of Keir. This work contains recom-
mendations for the treatment of grouse and low game
shooting from the point of view of the forester and timber-
grower, and makes the proposal to reduce Black Game from
the status of game birds to that of forest vermin. With this
finding, all who have had experience of the depredations of the
species will, we believe, be found ready to agree, with but
little reluctance.

BIRDS BREEDING IN THE LONDON ZOOLOGICAL
G.ARDENS. — This has been a good season and about one
hundred and fifty had already bred by the beginning of July,
although, for foreign species, the season was not more than
half over then. The expectations and prospects were that this
number would be considerably augmented. The Wigeon does
not commonly breed in confinement, but of this nati%e British
species there were fifteen well-grown ducklings, and another
brood was looked for. Amongst the young Gulls were three
interesting hybrids, the produce of the Lesser Black- B;icked
and the Common Gull.

ABUNDANCE OF THE COMMON SWIFT
iCYPSELL'S APUS). — It is far from easy to compare the
numbers of any of our commonly seen birds, season with
season, with any approach to accuracy. In any summer the
Common Swift is an abundant bird in the neighbourhood of
London, but this year it seems to be present in larger numbers
than usual, judging by the swarms which are now disporting
themselves in the district on the Middlesex and Hertfordshire
borders. In the neighbourhood of Bushey, for instance, a
glance around any morning or evening shows some dozens
within sight in the air. To attempt to estimate the numbers
would be futile ; but it may be worth remarking that, one day
in the month of May three years ago, 190S, the writer spent a
considerable time in attempting to count the numbers of a large
gathering of Swifts, hawking over the surface of the Brent
Reservoir, Middlesex, and approximately set them down as
some seven hundred or eight hundred birds,

BIRDS IN THE ELEVENTH EDITION OF THE
'•ENCYCLOPAEDIA BRITANNICA" 119111.— This work
contains reprints of the series of articles contributed by the
late Professor A. Newton to the ninth edition with some
small alterations. These articles are assuredly classics
in ornithological literature, but it is to be regretted that the
new edition does not contain the supplementary matter ^^■hich
Professor Newton himself included in republishing them in his
great " Dictionary of Birds" (1S93-6). This leaves the last-
named work, and not the new edition of the '" Encyclopaedia"
as the final and more complete authority on the birds included.
The " Encyclopaedia," however, contains fresh ornithological
writings in such articles as those on the general subject
" Bird," and on " Egg," " Feather." and so on.

PHOT(3GRAPiIY.

By C. E. Kenneth Mees, D.Sc.

TRI-COLOK PRINTING INKS.— To the Process Photo-
gram for July, Mr. A. J. Bull contributes an excellent article
on the rendering of greens in three-colour work, in which he
directs attention to the fact that the difficulties mot in repro-
ducing greens by the three-colour process, are mainly due to
the fact that even the best blue inks used for that process
have but a low reflecting power for green light. In a totally
different article, that by Sir Harry Johnston on the art of
painting, in the Westminster Gazette, we find another
indictment of three-colour printing inks from the point of
view of the artist. He writes : — " Fortunately for painters, a
stereotyped reproduction in colour is hampered at the present
day by the miserable quality of the inks and pigments used by
all colour printers (except here and there in Germany, Austria,
and France)." This would seem to imply that Sir Harry
Johnston considers that the printers are to blame for the poor
quality of the inks and pigments that they select, but it would
be interesting to know on what grounds he makes exception in
favour of certain printers in Germany, .\ustria, and France.
It may be true that there are printers in those countries who
produce better results than those produced in England or the
United States, — the present w-riter does not possess the
necessary knowledge to gi\e an opinion upon the subject, but
he doubts very gravely whether, if the results produced are
superior, the effect is to be ascribed to the use of better inks.
Colour-printing inks are chiefly made in large quantities by
big firms, and any ink that is on the market can be obtained
by any printer who desires it. nor does the price of an ink
necessarily increase with its suitability for three-colour work.

The real difficulty in the obtaining of more suitable inks for
the three-colour process lies in the wide separation between
the user of the inks and the original producer of the colour.
The user of the ink is the printer, but the colour is largely
chosen for him by the photo-engraver who makes the blocks,
and he, in his turn, is limited by the inks that he can obtain
from the maker, who is again limited by the lakes which the
dye works can supply. It is not to be expected that these
various commercial undertakings will all fully understand the
theory of the three-colour process, the only one of them who
actually requires the knowledge in e\ery-day work being the
block-maker, and hence, while most photo-engravers now
understand what inks they require, ink makers, as a rule, will
tell you frankly that they supply any colour of ink for which
they can obtain satisfactory lakes, and leave the choice of the
inks to the engraver. A visit some years ago to a great dye
works containing a section devoted to the preparation of lakes
for thiee-colour printing opened the writer's eyes to the fact
that the scientific chemists in charge of that section, had not
the least knowledge of the theory of the three-colour process,
and had not taken any steps to attempt to obtain permanent
colours of the right shade, the colours which the firm
reconmiended for the production of three-colour printing inks
being entirely unsuited to the purpose, and being selected
simply for their printing qualities, with \'ery little reference to
theoretical requirements as to colour. It is not too much to
say that there are no inks in existence which are both permanent
and of the right shade for three-colour printing, and the reason
for this is undoubtedly that the dye works have not yet produced
permanent lakes of the right shade. There is, of course, no
difficulty with the yellow ink, but the red ink always reflects
far too little blue, while the blue ink reflects only a small pro-
portion of the required amount of green. There are dyes
which are nearly of the right shade : some of the acid rhoda-
mines, for instance, are nearly the right shade of magenta, and
fast green blue shade, or patent blue would make a satisfactory
blue ink, but apparently the lakes which can be produced from
these dyes are not fast to light, so that for improvement in
colour-printing, as in so many other things, we must look to the
scientific chemist at the base rather than to the ink-maker or
printer who are dependent upon him for their materials.

THE DEVELOPMENT OF QUANTITIES
OF N E G A r I \' E S . — When a large number of exposed

324

KNOWLEDGE.

August, 1911.

plates have accumulated one's thoughts turn to methods of
handling a larger number of plates at the same time than
would usually be eniployed and the ease with which several
plates can be developed in a tank is certainly one reason
for the popularity of tanl< development. Tank development,
however, introduces a number of possible difficulties which are
less likely to occur during development in a dish. In the first
place a tank should be selected which can be reversed or shaken
so that circulation of the developer can be assured, because
otherwise there is considerable danger of accumulations of
oxydised developer which may produce most unexpected marks
upon the plate. A photograph of a church tower against the
sky, for instance, which is left quiescent in a tank with the sky
downwards may show upon the prints a white mark extending
up into the sky from the tower. This is owing to the fact that
the developer on the face of the plate immediately over the
tower does no work, and consequently remains fresher than
the developer covering the rest of the sky, and this fresh
developer slouly streaming o\'er the sky immediately below
the tower produces a streak of greater density in the negative,
which appears light in the print.

If a very dilute developer is used for prolonged development,
generally known as " stand " development, marks of obscure
origin are often met with and such a developer may gi\e rise to
a considerable amount of general fog. The reason for this
fogging by dilute developers has not hitherto been understood,
but some recent observations would appear to show that in some
cases, at any rate, it is due to the lowering of the sulphite concen-
tration in the developer, and may be removed by addition of
sulphite when the developer is diluted. .\ difficulty with
many developers when used for stand development, is that it
is impossible to calculate the time of development from the
dilution, because the reducer is oxidised by the air dissolved
in the water used. The dilution of one part of a metol
developer, for instance, with nine parts of water, will not give
a developer requiring ten times as long for development as the
original solution, but a longer period will be required, the
extension depending upon the air content of the water used
for dilution. A reducer, which appears to be almost entirely
free from this defect, and which, therefore, must be little
amenable to aerial oxidation, is glycin, which is pcculiarlv
suitable for timed development with weak solutions.

PHYSICS.

FRESH SUPPORT FOR PROFESSOR BICKEKTON'S
THEORY. — The conclusions of Professor Kapteyn's recent
address to the Dutch Science Congress, based on his own and
other observations, furnish a most remarkable case of the
fulfilment of physical deductions and predictions.

For over thirty years Professor Bickerton, of New Zealand,
has with increasing emphasis been making cosmic dynamical
deductions and publishing papers and books, showing that
every characteristic of our Galaxy can be most easily
e.xplained by assuming that it is made up of two cosmic
systems, of different orders of development. Ages ago these
two systems interpenetrated one another, coalesced, and
swung off the double spiral of stars called the Milky Way.
The idea was very clearly shown in a paper in the Pit Ho-
sophical Magazine for .August. 1900. Kapteyn's conclusions
are as follows : —

" The Stellar system was not originally a single system in
which the two known drifts or currents have developed ; but
the present system is the result of the encounter of two systems
which originally were entirely independent of each other."

" The primordial matter is now more abundant in the drift
of less star-density, and is almost entirely absent from the
opposite drift which is richer in stars."

Kapteyn's system of much primordial matter is Professor
Bickerton's cosmic system of the first order, which on
dynamical grounds he shows must grow up in the empty parts
of space. One of these primordial systems has interpene-
trated with one of a higher order. Such impacts, to quote
Professor Bickerton's paper in the Pliilosupliical Magazine,
will produce a cosmic system of a third order, of which our
Galactic .system is a type.

For some years back, in Australasia, there has been growing
up a belief that this new cosmogony is true, as it has anticipated
in a remarkable way so many subsequent discoveries. This
belief has culminated in the New Zealand Government sending
Professor Bickerton to England to present it as a working
hypothesis to guide astronomical research.

In our next number Professor Bickerton will tell the story
of Nova Persei, the new star of the new century, that in less
than two days grew from invisibility, to be actually the
brightest star in the Northern Hemisphere. Had the flash of
this temporary star been seen at the same distance as our Sun.
this huge celestial light would have been ten thousand times
as bright a blaze as the Sun itself. Professor Bickerton says
that all new stars are the explosively hot third bodies, torn
from grazing suns. The surprising number of phenomena that
were scientifically deduced, as possessed by this vast cosmic
spark, a score of years before Nova Persei appeared, and the
complete way .all have been demonstrated by astronomers,
reads more like a fairy tale than a statement of sober fact.

SEISMOLOGY.

A SEISMOGRAPH ATA LONDON ICNHUJITION.— At
the Coronation PIxhibition. Shepherds Bush, there is this year
one very interesting sight — a seismograph actually at work.
The exhibitor is Mr. J. J. Shaw, of West Bromwich, and he
believes that this is the first time that a seismograph has ever
been publicly exhibited under working conditions. He has
been fortunate in that, during June, two large earthquakes
occurred and were recorded by his instrument.

Mr. Shaw's instrument differs in several details from Pro-
fessor Milne's well known pattern which has been adopted as
the standard form by the Seismological Section of the British
.Association. The two horizontal pendulums are suspended
from separate brick columns and actuate multipl>-ing levers
which by means of glass needles record the movements on a
smoked paper roll carried on a revolving drum. These
two records are marked side by side with the time record
between them. This is, for popular demonstration purposes,
a method superior to that adopted by Professor Milne, whose
instruments give photographic records which require to be
developed before they become visible.

A record on the Seismograph, at the exhibition, of an earth-
quake in Mexico on June 5th, is only the second that has been
made on any instrument in London.

ZOOLOGY.

THE FLYING APPARATUS OF THE BLOWFLY.—
Dr. Wolfgang Ritter describes in Smithsonian Miscellaneous
Collections, Volume 56, No. 12, his researches upon the
flight of an insect. He finds that the downward movement of
the wings is caused by the contraction of two powerful dorsal
muscles, and he has repeated an old experiment illustrating
this. From a recently-killed fly, whose wings are raised, the
abdomen and head are removed and the thorax grasped with
a broad pair of forceps, so that one part of the latter is at its
anterior, and the other at its posterior end. On compressing
the forceps the thorax is shortened just as it is when the dorsal
nmscle contracts and the wings descend. The dorsi-ventral
muscles act as antagonists to the dorsal, and by compressing
the thorax in a vertical direction, raise the wings. A direct
muscle brings the wings back from the position of flight to
that of rest. Other direct muscles, which probably act as
steerers, draw the wings respectively forward and backward
and depress various portions of it.

THE SPIRIT BUILDINGS Al lUL BRITISH
MUSEUM (Natural History). — It has been announced that
an amicable settlement has been arrived at between the
Trustees of the British Museum and the Office of Works with
regard to the site for the Science Museum, for which the
ground now occupied by the Spirit Building, with its important
collections of zoological specimens in alcohol, was demanded.
No further official information is forthcoming, but it is said
that the arrangements that have been made will obviate the
necessity of pulling down the building in ijuestion.

FLIGHTLESS BIRDS.

MATTHEW D.WENPOKT HILL. ^LA.. F.Z.S.

The powt-r of fli,t;lit is uiidoulitcdly one of the most
marked characteristics of hirds. Yet we ktiow that
time and again birds belonging to widely different
orders have lost it, accompanied to a greater or less
extent by atrophy of the wings and pectoral arch.
It is interesting to consider, as far as possible, what

^■'

Figure 1.

Hcspcrornis rcgalis Marsh (restored) from the

Cretaceous of North America.

changes in environment ma\- have brought about
such striking modifications, .\lthough the absence
of enemies, and abundance of food close at hand
mav suggest reasons for the loss of flight in such
birds as the Kiw i and Owl Parrot of New Zealand,
yet it is probable that here, as elsewhere, the law of
correlation of structures, about which at present we
know so little, has played a part in the transforma-
tion, coupled with a change in the habits and
circumstances of the ancestors of flightless birds.
For there can be little doubt that the reptilian

cannot be regarded as being in the direct line of

forerunners of birds generally were terrestrial, and
probabh' arboreal, animals, not aquatic, as some
writers have suggested. In an_\' case the pterodactyles

r.fT

-b

descent of birds.

Archaeopteryx Iith(i:^i\iphiijii. the most ancient, as
well as the most primitive bird. " created," as
Huxlev said, " to prove the truth of the theory of
evolution," had well-developed fore-limbs, even if
the\' were not ver\' ser\'iceable wings, and hence, we
may assume that in all cases flightless birds have
descended from flx'ing ancestors. Bearing this in
mind, it is certainlv remarkable that one of the most
ancient known birds. Hcspcrornis (see Figure 1).
fiiund in the Cretaceous shales of Kansas, had lost
the power of flight completely. In fact the wing-
bones were absent, and the breast-bones and pectoral
arch much reduced. The bird was a gigantic diver,

Figure 2.

Phororliacus loH}>issinins Ameghino (restored) from
the Santa Criu Bed (? Mioceue) Patagonia.

.525

326

KNOWLEDGE.

August. 1911.

FiGUKE 3.

Acpyornia iiuj.xiiniis Geoffroy (restored) from the
Pleistocene of Madagascar.

allied to the grebes of tn-d:i\'. so well adapted to an
aquatic habitat that it i>r(>bably rarel\-, if ever,
walked on land. The set-back of the legs, and the
large knee-cap and enemial crest seem to have
rendered an erect position impossible. The mouth
was well provided with teeth, set like a lizard's in
a groove, not in distinct sockets. The remains of
other Mesozoic birds have been found which, barring
the possession of teeth, are not very different from
modern forms, e.g., Ictliynniis allied to the gulls.

Unfortunateh- for the palaeontologist the bones of
birds are rarely found fossilized. Their lightness
prevents them in a great measure from sinking, and
thus being covered up b\- some sedimentary deposit.
a necessary step in the process of fossilization.
Hence it is not hard to understand win-, with the
important e.xception nf Archaeopfcryx. as \ct no
remains of an^■ intermediate forms between reptiles
and birds have come to light.

In the Santa Cruz lied (? Miocene) of South
America we find the remains of another giant
flightless bird Plwrorliacos. allied probabK- to the
Secretary Bird of South Africa. The reason for

the large size of many flightless birds is not hard
to see. .\mong the extinct pterodact}des, as well
as in birds, there is a strict limit to size when the
body has to be raised into the air. Muscular tissue
and general vertebrate anatom\' being what it is. \\e
may safelv assume that no animal much larger than
a swan ever tfew through the atmosphere of our
planet. But as soon as the necessity for tlight is
removed, so likewise is the embargo on any increase
in size, and natural selection has a free hand. Size,
strength, and fleetness of foot have often to make
up for loss of flight. A few generations, probably,
were sufficient to ]>roduce a marked increase in
weight and stature in a bird that had ceased
to fly. To return to P/iororhacos. The bird had
certainly a larger and more massive head and beak
than any other \et discovered, and it is not im-
probable that it resembled P'igure 2. It is portra\ed
killing a lizard, but there can be little doubt that
it would have made short work of anv living snake
if its habits and mode of attack were the same as
those of its smaller modern relati\'e.

Figures j and 4 are those of Acpyornis and

Figure 4.

hiiKirnis inii.\:iiiiiis (Jweii (restoredl from the Sand-hills
of New Zealand.

August, 1911.

KNOWLEDGE.

327

Diiioniis (the Moa). The first of these — the
eggs and remains of which have been found in
Madagascar — is generalh' believed to be tlie
original of the '" Roc." and certainly lived down
almost to historic times. It was a flightless,
ostrich-like bird that laid one enormous egg at a
time. Specimens ha\e been found measuring
IJ inches bv 9-5 inches. In this connection it is

interesting to note that the Apteryx, a modern
flightless bird of New Zealand, about the size of a
fowl, lavs, likewise, an egg entirely out of proportion

to its bulk, being very nearl\- as

big as that of

a swan. Doubtless in fl\ing birds the eggs are
necessarily prevented from becoming ver\- large,
to ensure that the bird does not become too heavy,
but in those that are flightless there is no such need.

I To he coiitiiiiiCii.)

thp: time of niGii water.

By J. A. HAKDCWSTLE.

.\t this time of the year so many people enjoy the sands and
the bathing at the seaside, that the time of High and Low-
Water is a subject of considerable importance, and the wise
man will consult a local tide-table if he wishes to choose the
best date for his visit or indeed the best seaside resort for his
purpose. The Norfolk coast has long enjoyed a great popu-
larity, yet it is more than probable that no one has noticed one
great advantage that it possesses, a feature, the loss of which
would be more detrimental than the disappearance of the
much-vaunted sands. It consists in the particular value for
that coast of what is technically called the "establishment,"
a list of which <iuantities is given in Wliitakcr's Almanac
page 68. The value for Cromer is five hours — meaning that
High Water occurs there five hours after High Water at
London Bridge.

It is common knowledge that each day the tides occur fifty
minutes later, and consequently, in the course of fourteen days
they go all round the clock, and the moon also passes from new
to full and full to new in fourteen days. Consecjuently if High
Water occurs at noon on the day of new moon it will occur at
noon also on the day of full, and in fact all the Spring Tides
will be high at noon. It is also well known that the tides
proceed round the coast and on any one day High Water
occurs at a different moment at different ports. Thus, for
instance. Spring Tides are high at Aberdeen at 2 o'clock, at
Cromer at S o'clock, at Brighton at 12; these hours may be
taken as both morning and afternoon since there are practically
twelve hours between any two high tides.

I can well remember my disappointment as a child at
hearing again and again of wonderful high tides beating on
the sea-wall at Cromer, but they always happened when I was
in bed because the Cromer Spring high tides occur at
8 o'clock ; but then on the other hand the Spring low water
laid bare the best sands and sometimes even showed us the
old Church Rock, and these low waters always occurred in
the middle of the day. This then is the first point of advan-
tage conferred by the " establishment " ; the lowest tides and
the best sands happen in the middle of the day. Now at
Kamsgate the "establishment" differs from that of Cromer
by seven hours and so the Spring flood-tide is in the middle of
the day and the best of the sands are bare at 7 a.m. and 7 p.m.,
which is far less convenient.

It will, however, be urged that the loss of that particular
low tide to the visitor who stays a fortnight is not serious. A
week later Cromer will be having low water at 7 or 8 o'clock
and Ramsgate at about noon, and though those will indeed be
Neap Tides, the difference scarcely matters much.

But that rejoinder betrays ignorance of one of the most
interesting features in the run of the tides, which is called
their priming and lagging.

The following Table gives the times of High Water at

Cromer for September and October. 1911 : the first column
being drawn up on the assumption of a uniform interval of
fifty minutes from day to day, the second gives the actual time
of High Water — while the tliird gives the actual intervals.

1 01

Tide

Table for

At uniform

Cromer.

At true

lyix.

intervals.

intervals.

Sept.

21

5.46 a.m.

5.46 a.rr

1.

„

22

New Moon

6.36

6.34

48

C

23

7.26

7.13

39

c

24

Springs

8.16

7.48

35

c

25

9.6

8.22

34

c

26

9.56

8.57

35

c

27

10.46

9.28

31

c

28

11.36

9.58

30

c

29

12.26

10.32

34

30

1st Or,

1.16

11.12

40

Oct.

1

2.6

12.6

54

I

■7

Neaps

2.56

1.19

73

I

3

3.46

2.58

99

I

4

4.36

4.23

85

'I

5

5.26

5.21

58

6

6.16

5.59

38

7

7.6

6.35

36

c

1,

8

7.56

7.7

il

c

9

8.46

7.39

32

c

10

9.36

8.15

36

c

11

10.26

8.50

45

c

Let us suppose that the most convenient hour for the
summer visitor to ha\e low water is between 12 and 4, while
the most inconvenient is between 6 and 10. Our Table gives
High Water so we must state it thus : —

Convenient days High Water from 6 to 10.
Inconvenient days High Water from 12 to 4.

I have marked with a C and an I these days respectively — and
one sees at once that there are seven convenient days and
only three inconvenient days, while five days are inditTerent,
After fifteen days everything repeats itself. The reason is
apparent by reference to the third column. Spring tides
occur two days after new and full moon, for certain reasons
that need not now concern us, and for three or four days before
and after the Springs the tidal intervals are very short ; the
tides are said to be priming. On the other hand at Neaps
the tides lag and the intervals are long.

If, therefore, the "establishment" is such that Spring tides
occur at a favourable hour in the day — you will get perhaps
seven very favourable days to three unfavourable — or roughly
speaking it is two to one in favour of the tripper finding the
sands convenient for him at Cromer. At Brighton it is precisely
the opposite, seven unfavourable to three favourable days.

REVIEXWS.

ARCHAEOLOGY.

The I'trsf tit (iiir Duors : Or The Old in the Xcic arninid lis.

B\- W'am'kk W. Skeat. M.A. I'KS pages. 52 illustrations.

4viii. X 7-in.

(Macinillan & Co. Price 16.)

The second title of this book gives perhaps the better idea
of its contents for they deal with the story of our food, our dress
and of our home. To a great extent the origin and use of the
names comes in for attention, but those who like to trace the
history of the things around them from the small vestiges and
peculiarities which survive, will be charmed with the book.

We learn the meaning of the dairy where bread was
originally kneaded : a hamper was once a basket to hold a
particular kind of drinking cup : the hearse took its name from
a framework of spikes like a harrow on which to stick candles,
and for that reason was given the same name as a harrow.
Even in connection with the story of our home, trade signs are
considered, while the subject of clothes is one that is always
attractive.

HACTERIOLOGV.

Aids to Bcictcriology. — By C. (i. M(ini;. M.A. 240 pa.ges.
4f-in. X 6rl-in.

(Haillicre, Tindall ^: Cox. Price 3 0 net.)

This little book, of whicli we welcome a second edition,
contains many useful hints both for those who are not
familiar with bacteriology and those who are working at
the science and want to find, easily, details as to methods of
preparation, staining, collection of samples, and the general
points to be borne in mind with regard to various diseases
wliiili .ire due to bacteria.

kioloca:

TIic Biolofiy of the Seasons. — By J. Arthiir Thomson.
J84 pages. 12 coloured illustrations. 5.j-in. X 8i-in.

(.\iidreu Melrose. Price ID () net.)

Professor Thomson's book is full of interest, because, not
only does he give us facts and put them before us in his own
way, but because he discusses theories and reminds us that
there are still differences of opinion in many liiological matters.
As the name implies, the treatment in the book is
seasonal, following that natural but informal sequence, which
is one of the great advantages of what is known as nature
study, which is scientific but not science. As may be
expected, birds come in for a good share of attention, the
meaning of their song for instance is discussed and the
question whether they learn to buikl their nests or instinctively
construct them is considered.

We may mention also the chapter on the migration of eels,
and most particularly that dealing with adolescence. The
book is illustrated by a number of reproductions of coloured
sketches, which are certainly a change from the photographs
from which most popular books are now illustrated, but they
are mounted on paper which is so dark that it detracts from
their effect.

We should like to see " The Biology of the Seasons " very
widely read.

BOTANY.

I^ife Histories of h'aniiluir I'hiiits. — ISy Joii\ J. Ward.
204 pages. 120 illustrations. .=i-in. x 7| -in.

ICassell 6c Co. Price .! 6.)

Iti natural history familiarity is far from breeding contempt,
and there is so much to learn about e\en the commonest

creatures, that it \Miuld lie strange if Mr. Ward's book had
not proved successful, as the call for a popular edition shows
it to have been. The photographs are exceedingly good, and
reproduced plainly and simply without any of the fiunnnery or
inartistic combinations which occur in many nature books.

CHICMISTK^'.

Clieiiustry tor Mat neiitation. — Bv (".. H. Baii.kv.

D..Sc. Ph.'n.'and H. W. Bausor. M.A. 54.S pages. 110

illustrations. 7-in.X5-in.

(University Tutorial Press. Price 5 (>.)
This book, as its title suggests, is intended to help students
across the pitfalls of the Matriculation Examination of the
Uni\'ersity of London. It is divided into four sections,
\'\/..: — I. dealing with the general principles of Chemistry;
II, with the non-metals ; III, with the more connnon metals and
including a chapter on electrolysis: ,iiid 1\', with chemical
calculations.

Since the pass-list is the ultimate aim of the book, its
contents are of necessity rigorously compressed and all
extraneous matter is excluded, but the experiments are so well
chosen as to remedy to a large extent the usual bad effects of
such compression. The ground required for the examination
is certainly most efficiently covered, and even students who
are not working under the shadow of examination will find the
book of use to crystallise their knowledge. CAM

Tlie Clieiinst ly and Testing of Cement. — By C. H.
Di-scH, n.S> . 2o7 + X. pages, 'j plates. 5n-in. X SA-in.

(I'dw.ird Arnold. Price 10 6 net.)

Dr. Desch's book is of interest to the scientific chemist
mainly, owing to its able discussion of the chemistry of the
setting of cement.

In confining himself to the scientific side of the question,
Dr. Desch, in his book on " The Chemistry and Testing of
Cement," has filled an hitherto conspicuous gap in the ranks
of modern cement literature. There are many excellent works
dealing with the practical aspect of the industry, but none of
these deal iii an exhaustive manner with the questions so
efficiently discussed by Dr. Desch.

The author has gathered the results of researches dating
from the time of Le Chaletier to the present day, and presented
them to his readers in a concise and masterly fashion. The
subject is thus shewn to be a fascinating one, and there are
still many opportunities for further research. The work under
review indicates the lines along which future work must
proceed.

On experimental grounds the author finds himself unable
to accept the crystalline theory of setting advanced by
Le Chatelier. This theory supposes the setting of the cement
to be due to the interlocking of crystals of hydrated silicates
of calcium. Dr. Desch considers the experimental evidence
in support of this view to be insufficient. Microscopical
examination of a hardened cement, according to the author's
own researches, does not reveal the presence of a sufficient
proportion of crx'stalline constituent. By far the larger pro-
portion of the constituents appear to be amorphous. From
this. Dr. Desch is led to support the views of W. Michaelis,
who su.ggested, so far back as 1893, that "the calcareous
hydraulic cements owe their hardening mainly to the forma-
tion of colloidal calcium hydro-silicate."

Dr. Desch says: "The theory (of Michaelis) so well
explains the phenomena observed, and is in such good
accordance with the results of microscopical investigation of
cements during and after setting, that it must be held to
contain at least a greater part of the truth."

The hardening of cement Dr. Desch considers to be due to
the loss of water experienced by the colloidal bodies formed.

Many interesting experimental data are given.

328

August, 1911.

KNOWLEDGE.

329

The mechanical and physical properties, their determination,
and the mechanical analysis of cement, also receive careful
attention.

The book may be represented as containins,' the most
modern accepted views of the chemistry of cement, and is a
highly important and successful addition to existing literature
on the subject. It should find a place in the library of every
scientific chemist.

\V. A. B. W.

Modern I mbistnal Cliciinstry. — From the German of H.

Blucher. translated by J. P. Millin-gtox, M.A. 779 pages.

' 6i-in. X9i-in.

(The Gresham Publishing Company. Price 30 - net.)

This volume is really a chemical dictionary. Reference to
a number of the items considered in its pages shows that the
information contained in it is full, considering the amount of
space there is to spare, and we have no hesitation in saying
that it will prove most useful, not only to chemists but also to
the mass of educated persons who often wish to know more
about some substance or process of which they hear or read.

simple language just the information required by those
interested in weather observation, and by following the
instructions given anyone will be able to bring his local
record into line witli others and thus greatly increase its
value.

The volume includes a set of Meteorological Tables, together
with a particularly useful glossary of Meteorological terms.

MICROLOGY.

Animal Micralogy. — By Michael F. Guver. Ph.D.
240 pages. 71 illustrations. 6-in.X9-in.

(Cambridge University Press. Price 7, ■ net.)

Brief, practical and definite descriptions of the most
important modern methods of microscopic technique have
been prepared by Dr. Guyer and combined with a simple
account of the microscope and a consideration of standard
reagents, to form a useful book for those who are taking up
microscopical research. Methods of preparing material and of
examining particular kinds of creatures are also explained.

MATHEMATICS.

Orders of Infinity : the Infinitdrcalciil of Paul dii Bois-

Reymond. — By G. H. Hardy, M.A., F.R.S. 62 pages.

Sf-in. X5s-in.

(Cambridge University Press. Price 2 6 net.)

This work forms No. 12 of the valuable series of short
mathematical tracts entitled " The Cambridge Tracts in
Mathematics and Mathematical Ph\'sics." published under the
general editorship of Messrs. J. G. Leathem. M.A., and E. T.
Whittaker, M.A., F.R.S.

As Mr. Hardy remarks in his preface, " with the pasticular
system of notation that Du Bois- Reymond invented, it is, no
doubt, quite possible to dispense ; but it can hardly be denied
that the notation is exceedingly useful, being clear, concise,
and expressive in a high degree " ; and mathematicians in this
country will, no doubt, be grateful to Mr. Hardy for
presenting them with Du Bois-Reymond's valuable ideas in an
English dress. Du Bois- Reymond, unfortunately, is at times
highly obscure, and many of his proofs can hardly be regarded
as conclusive. Mathematicians have further to thank Mr,
Hardy for largely remedying these defects, and for bringing
the " Infinitarcalciil " up-to-date. It is rather a pity that lack
of space has prevented him from discussing the various points
that arise in the book rather more fully than is done ; and it
would certainly have been an addition welcomed by readers
whose mathematical abilities are not of quite the highest
quality had the general proofs been more freely illustrated with
specific examples.

There is an interesting paragraph on pages 25-2(i dealing
with the attempts (which do not appear to ha\e been
altogether successful) to represent orders of infinity by means
of symbols. The writer is inclined to consider this subject, in
its present condition, as being merely of the nature of a
mathematical curiosity : we venture to suggest, however, that
with further research it may prove to be of no little
importance.

An appendix containing a bibliography of the subject, as

w-ell as another containing some numerical calculations (made

by Mr. Jackson, scholar of Trinity College) bearing on the

subject of the work, add to the value and interest of the

book. ,, ,, „

H. S. Redgrove.

METEOROLOGY.

Hints to Meteorological Observers. — By W. Marriott,
F,R.Met,Soc. 75 pages. 25 illustrations. 9s-in. X 6-in.

(Edward Stanford. Price 1,6.)

We are glad to see that a seventh edition of this very useful
little manual has been called for, and this fact is perhaps the
best testimony to its worth. Mr. Marriott gives in clear and

NATURE STUDY.

Nature's Pageant. — By Margaret Cameron, LL..A.
120 pages. Numerous illustrations. 6i-in. X Sj-in.

(Blackie & Son. Price 1/-.)

This book, which is intended for very young children,
carries out the nature study idea in so far as it deals with the
seasons. It is, however, open to the objection that in it the
animals are endowed with speech, and though fairy tales as
fairy tales are interesting and stimulate imagination, much of
the false sentiment of modern times is due to dealing with
animals as if they had exactlv our thoughts and feelings.

PSYCHOLOGY.

.4/; Introduction to E.xperinicntal Psychology. By

Charles S. Myers. \LD.,Sc.D. 156 pages. 20 illustrations.

6j-in. X 5-in.

(Cambridge University Press. Price Is. net.)

On the scientific merit of Dr. Myers' little book the verdict
of expert opinion will be favourable. The topics for treatment
are well selected ; the treatment itself is careful, lucid and
effective. Those who are not experts will probably turn to this
brief introduction to ascertain w'hat are the claims of those who
advocate the application of the methods of experiment in
psychology, and how far there is some promise of these claims
being made good. We fear their off-hand verdict may not be
so favourable. They will turn, perhaps, to the chapter on
memory, and they will find that the experimental work deals
with the associative linking and subsequent revival of pairs or
groups of nonsense syllables. They will wonder why such
emphasis is laid on the nonsensical, and ask, perchance,
whether this, then, is the new psychology. All suggestion
of meaning seems to be regarded as a disturbing factor, which
only ceases to give trouble " as the subject becomes more
expert." They should remember, howe\-er, that what we glibly
talk of as memory is a pretty complex business, and that the
only chance of dealing scientifically with such a complex is to
follow up in detail the several threads which are subtly inter-
woven. They should remember, too, that, in the course of
experimental work, the mere fact of endeavouring resolutely to
exclude meaning is a means to the realisation of how readily
some significance is apt to be suggested. Dr. Myers might,
perhaps, have insisted on the value of the experimental method
in stimulating that introspection to which the novice in
psychology is comparatively unaccustomed. The current
perusal of such a book in a spare hour will not enable the
reader to do justice to its merits, or to grasp how much real
psychological value there is in experimental work. „ .

330

KNOWLEDGE.

AUGl'ST, 1911.

TOPOGK.AFHV.

Burma: A Handbook
Political Information.-

of Practical. Commercial and
-Bv Sir George Scott. K.C.I.E.

520 pages. Numerous illustrations. D:|r-in.X 7J-in.

(Alexander Morint,'. Price 10 (< net.)

Sirr George Scott's readable account of Burma is well
known, and in noticing the second, new and revised edition,
we may say that Natural Histor\- and Geology are considered
in some detail, while the hints to visitors or new residents
make the book more valuable.

Piiuis (if ."^hwic:). \'oliimc I. — By C. George Richards.

153 pages. 262 illustrations. 13i-in. X 9j-in.

(H. P.. Shrimpton. Price 42 - net.)

During his wanderings amongst the ruins of Me.xico, Mr.
Constantine George Richards has collected a fine series of
photographs, and to form the first volume of his book which
is now before us, he has put together two hundred and
sixty-two collotype reproductions of his pictures. In his
introduction he says that there is nothing scientific, literary, or
new in his work, but those who are privileged to see it will be
ready to assure him of the value of his records of the ruins of
the times before the Spanish Conquest.

OUERIE.S.

Readers are invited to send in Onestions and to ansu-er tlie Oi(eries xcliicli are printed lure.

46. BIBLE ASTRONOMY.— What would be the effect on
our planet and other of this system if the sun and moon were
to'stand still as stated in the book of Joshua in the Bible ?

J. W. A.

47. GR.WITV. — I heard it stated in a sermon, preached in
a village church a few Sundays ago, that the reason we do
not tumble off the earth is because it is surrounded by the
atmosphere, which keeps us from flying off into space. No
allusion whate\-er was made to gravity. Talking it over with
a friend afterwards, she informed me that gravity was now
rather discredited by scientific men, and that, if the atmosphere
was not the sole cause of our remaining on the earth. ,it all
events it had a good deal to do with it.

This is such a very novel theory to me that I venture to
write and ask you if there is any truth in it ?

IGNORAMUS.

48. THE COOLINCi OF HOT WATER.— There is a
popular belief that boiling water freezes faster than cold :
apparently it is also held that it cools more rapidly when the
thermometer does not fall to 32" F., for I have heard of very
hot water being put ready overnight for a bath in Jamaica in
the belief that this would furnish the coolest morning tub.
That the belief is false in most cases I have convinced myself
by a " fool's experiment " : on a night of hard frost I put out
water at boiling point, water that had boiled for some time,
and cool water, in similar vessels, with the result that might
have been expected : the cold water was ice some hours
before the others. But can you or any of j'our readers tell
me what gives rise to such a singular and unexpected fallacy ?
.Are there any conditions under which boiling water could
freeze more rapidly than water at any lower temperature ?

A. F.

NOTICES.

THE HOME OF GILBERT WHITE.— In The Country
Home for July there is a thoroughly-well illustrated article
on "The Wakes at Selborne," by Miss .Aimy .\stbury. We
believe that pictures of many of the rooms have never been
published before, and we are able, by the courtesy of Tlic
Country Home, to print below, one of the rooms in which
Gilbert White wrote " The Natural History of Selborne."

WHO'S WHO IN SCIENCE.— Messrs. J. & A. Churchill
are preparing a new annual book of reference which will
contain the names, appointments and achievements of the
foremost scientific men in the world. Schedules are now
being sent out and the cooperation of all those interested in
science is invited. The forms should be returned, as soon as
possible, to 7. Great .Marlborough Street, London, W.

The room m which Gilbert White wrote " Tiie X.itur.il History nl Sriliorne" and in which he afterwards died.

Knowledge.

With uhich is incorporated Hardwicke's Science Gossip, and the Ilhistrated Scientific News.

A Monthly Record of Science.

Conducted by Wilfred Mark Webb, F.L.S., and E. S. Grew, M.A.
SEPTKNn^KK, 1911.

THE TRUE STRUCTURE OF THE DLATOM

VALVE.

By T. F. SMITH.

(Coiitiiiuai from page 293.)

Figure 14 is from the inner side of another valve,
the first ever seen and taken, showing the fracture
through undoubted perforations. The strongest
argument hitherto for " beads " in the liner forms

aKva\'S ran between them,

was that the fracture
as the weakest part.
Mr. E. M. Nelson,
at the discussion in
the Ouekett Club,
gave this testimony :
"The difficu]t\' has
al\\a\'S been felt that
in foniiosiiiii the\"
had never been abh'
to see the holes : but
no\\' it was show n
that there was. ini-
doubtedly. a per^
forated membrane :
the\' could take it
and see for them-
selves that it was a
perfectly plain thing;
indeed, if this was
not real, then he
could onh' sa}" that
all other things were
hocus pocus. With
their very best lenses
thev had tried to find

out about fonnosiim. Mr. Smitli had found this
fracture, had shown it to him, and that at any rate
the fracture did run through the holes." This

Figure 14. The inner side of P/c';(;-osi^/)!rt fonnosmn

showing the fractures through the holes, the first ever

seen under these conditions, X 1750.

here not in any spirit of self-
glorification" on the part of the present writer; but
rather that so valuable a testimony should be
added to strengthen his own.

Particular attention is also directed to this print,

as it exhibits a
«te^ structure of squares

instead of the cus-
tomar\" round beads.
This is in accordance
with the theory of
Dr. .\bbe. expressed
in his paper on the
relationship of aper-
ture to power. He
shows there that all
the optical details of
an object developed
w ith insufficient aper-
ture to resohe them
properlv, whether
square, 1 oze n ge-
shape, or triangular,
are depicted either
oval or round.
Figure 4, from the
same side, where the
valve has not been
acted upon, may
seem to contradict
this view . The present writer, however, has already
given his opinion that these appearances do not
denote structure, but are only a collection of focal

331

332

KNOWLEDGE.

September, 1911.

Figure 15. Inciiuiur sidu ul I'lcurosigma fonuosiiiu

where the valve has been acted upon in parts, leaving

bare the fibrils or grating, X 1750.

images thrown from

the other side of the

vahe, as on a screen.

The structure does

not seem to differ

much in cliaracter

from that of the

outside, except in . •

being more robust. -

See Figure 15 for i

this, taken also from ,

the inner side.

Comparing the

o()tical results from

the same diatom, in

the photographs

taken both b\' the

oil immersion and

the dry lens, is there

any reason for r-,^.,,,,. ic tt * i

. ■, . , Figure 16. Fragments ot

doubtmg the utter one showing the outer and

futilitS' of attempting

to elucidate further the structure of P. fttninisiim
with an objective of only 1 -0 N.A.? Yet the Tnjus-
dcfiuiis of flic Royal Microscopical Socicfy show that
this feat has been attempted by one of its Fellows
within the last two or three years. The chief,
the almost sole, advantage of the oil immersion
apochromatic lens is that bv its refinements
of correction it can stand more light, and have
more of the available aperture utilised. The
almost possible limit of resohing power was
reached by the old glasses with an aperture pushed
to l-5(). It was proposed to carry resolution still
further by an objective of only 1 •(), with a top-stop
as an accessory. The results are recorded and
figured in the Traiisacfioiis — let the readers of
" Knowledgk "■ compare them.

torn structure to confirm the practical identit\- of the
two. In P. fonnosiim we can obtain it in long chains,
as it were, here we shall find only links. Yet to those
who know a chain when thev see it, identical links
should be sufficient for evidence. Indeed, from the
\arious processes to which the valves are subjected
It is only to be e.xpected that the more fragile forms
will get the most damage, and the\- do. The
jihotographs of this species have been enlarged
twice, for the better comparison : figure 16 shows
the fragments of two valves, each with the opposite
face outwards, forming a striking contrast. The
torn structure seen just abo\e the median line is
from the outer side, and exhibits similar fibrils, with
the same arrangement as in P. formosuin — more
especially seen at the left-hand bottom corner of the
picture, where it is marked with a X — exhibits the
same focal itnages, projected from the other side of
the valve. Above this again it will be seen that
we get the normal aiipearance of the o//^er side when

sound, and, in the
uppermost division in
strong contrast the
characteristic hexa-
gonal structure of the
inner side. Figure
17 is another ex-
ample from the outer
side of still more
torn structure;
-\ further, it is put here
also to i)oint a moral,
if not to adorn a tale:
for there is a tale.

Throughout the
greater part of the
period over which
the history of the
achromatic micro-
scope extends, this
species has been
emplo}'ed as a

\

'>«

the \ai\e ot P. angiilcitiiin,
one the inner side, X 3500.

When we come to P. an^iilatiiiii we are dealing
with structure of just double the fineness, where it
is not so easy to get such striking examples of the

Figure 17. The outer side of the same, X 2500.

September, 1911.

KNOWLEDGE.

355

general test object, to illustrate different observers"
theories. It has also been used to measure the
advances, or the supposed advances, in the revealing
of structure. Sometimes it has served as a proof
that it can offer no evidence of the real structure at
all — Dr. Abbe to wit. In the September number
of Harper's Magazine, for 19(17, there is an article
on photo-micrograph\- with the ultra-violet ra\'s,
under which it is claimed that the resoh'ing power
of the microscope has been recently doubled. The
customary P. angulatiiin is ushered in to make valid
this claim. B\- an ingenious and. I am afraid, a
somewhat disingenuous arrangement, two photo-
micrographs of this diatom are placed side by side,
one taken under the ordinary
illumination and the other
under the ultra-\'iolet light, to
prove it.

Now, somebod\'. somewhere,
must ha\-e been taken in at
the same time, for this sup-
posed new structure was seen,
and photographed, by the
present writer twent\' \ears
pre\'iousl\-. It had not then,
and has not now. any special
significance for him, except in
illustrating his theory of focal
images. Neither is it a severe
test of the resolving [)()wer of
the microscope : an\' oil im-
mersion of 1-JO will suffice.
The statement is from
Germany, which produces some
of the best micro-objectives in

the world, and is also the home of some of the
worst micrograph\'.

Of course, one does not wish to imply that the
resolving power of the microscope cannot be
increased, or even doubled, by the use of the ultra-
violet light, onlv that the e.xample given does not
prove it. As far as memory serx-es, the method
stated as being employed did not give much promise
of future great discoveries. The object was not
seen at all, sureh- fatal to accurate and refined
definition. To know one's subject thoroughly it is
necessary to work out the details under the
microscope while sitting down, in order to recognise
what to go for, before attaching it to the camera.
More practical, the late Dr. Dallinger advocated
increasing the resolving power b\' the judicious use
of coloured screens. "^'et. after ex[jeriments, he
recognised that the objectives should be corrected
throughout for an\- particular ray.

Now. turning tt> the inner side of the valve,
enlarged as before, for better comparison, I'^igure 18
should give us the ke}- to the much-discussed
hexagonal structure. It offers, however, this charac-
teristic difference from the corresponding side of
P. formosum, that the fibrils or short bars of silex

Figure 18. The inner
X 3770, showing

instead of being placed lengthways are set obliquely
across the valve. It will be seen also that the zig-
zag arrangement of the isolated strip, if joined to the
broken edges bordering the clear spaces on each side,
would require no crossbars to complete the so-called
hexagons. .Another peculiarit}" is that this seems to
be real structure in which there are no focal images
to obscure it. The analogw in fact, would be more
with the hexagonal middle structure of the large
discoid and other forms.

There still remains the question of the intercostals,
which Mr. E. M. Nelson maintains are the products
of the second order of spectra only. If these are
not real entities, then why are the\- produced trom
this one side of the valve
alone ? The structure on both
sides is of equal fineness :
given the same conditions of
aperture and lighting, should
there not be produced the
same results ? However, per-
haps it is not well to express
too pronounced an opinion on
such a matter, ^^"e are dealing
here with appearances so
minute that six dots are
arranged around one that once
taxed the whole powers of the
microscope to define.

I'igure 19 is from a valve
of P. haJticiim. still showing
fibrils and also indications of
the structure underneath. The
appearances here have been
put down to moisture in
dr\- mount : but. as it happened, Mr.
E. M. Nelson exhibited the same diatom under
the celebrated new objective of 1-6J N..\., pres-
ented to the Royal Microscopical Society by
Zeiss. The object then was of a necessity
mounted in a dense medium, yet in all respects
it offered the same details as are figured here.
So much for moisture in the mount. It will be
seen that the fibrils differ to a certain extent
from the preceding examples. They appear in
this print as extended bars, with swellings at
regular intervals, seemingly, when together, gix'ing
the semblance to beads or squares according to the
aperture employed. This difference can be ascribed
to one of two causes. It mav arise from the true
fashion of the structure in itself, or from imperfect
resolution. Some countenance is given to this last
view bv referring back to F"igure 11*, taken with the
dry lens, where it will be seen the fibrils come out
almost straight, though b\- no means so when under
the wider aperture of an oil immersion. E\-ery
earnest student of Nature knows that often we arrive
at a point where we stand groping helplessl}' outside
the boundarv of knowledge. We mav hazard a guess
as to the right wa\' in ; but there our efforts must end.

side of P. angulatiiiii
the isolated sUp.

the

"See "Knowledge" for August, 1911, page 293.

iU

KNOWLEDGE.

September, 1911.

KlGURE IQ. p. haUicuiii showiiiL; the fibrils
and thr double structure of the vah e. X 1750.

All the work fit^urcd here
hitherto was done upon
diatoms mounted drw Later
the writer was able to com-
plete his evidence, of a unity
of structure, upon other
d i a t o m s m o u n t e d i n a
medium. I"i,L;ures 20 and
2] exhihit the same struc-
ture of tilirils upon a small
CosciiKuiiscus so mounted,
and luMui; of sufficient
thickness to allow the separ-
ate layers to be distinguisluil
by an oil immersion. Li
one [jrint the picture is much
more crowded than apjieared
under the microscope, where
the fine adjustment could be
used. Onl\- those who prac-
tice photo-micrography can
appreciate the difference be-
tween seeing things in the microscope, and putting
the same features \i\i<iK- upon a plate. X'isually
the fibrils were unravelled, la\er after la\er, as one
might unravel some woven matirial. b'igure 21,
taken at a slightly different level, shows two fibrils
projecting into space, well separated from evervthing
at the sides, above and below. E\'i(lentl\- tlie fibrils
seen in the two prints, and not Mr. .Slack's beads,
form the sides of the he.xagoiis of the middle la\'er
of this diatom.

It is not assumed here that all diatom structure
must be made up of similar fibrils. It is alwa\s
dangerous to generalise from too little data. On the
other hand the evidence is positive that much of the
structure is, and there seems nothing to preclude the
remainder from being formed of the same kinds of
units. How these fibrils are deposited upon the
true membrane of the lining vegetable cell is
another matter.

i^t^'iti-

I'lGCRE 20. .A small Co^^cuiotiisciis \al\e

mounted in balsam, showing the same kind

of fibrils forming the hexagons, X 1750.

This article would not be complete without
reference to Dr. Henry \'an Heurck's more recent
work upon diatom structure, with the new a[)Ochro-
matic objective of 1-63 N..\. Plate 11 of the last
edition of Carpenter was prepared by Dr. \'an
Heurck especialh' for that work. The description
reads: — "Thisiilate has a two-fold purpose. It is
designed, first, to justif\' the opinions held b\' Dr.
\'an Heurck u[)on the structure of the vah'es of
diatoms, and also to show how the usual micro-
scopical tests [iresent themselves when examined w ith
the new objecti\e . . . lately constructed by the firm
of Zeiss."

The editor (Dr. Dallinger) thus describes Dr.
\'an Heurck's views. " He concludes that diatom
valves consist of two membranes or thin films and an
intermediate laver, the latter being pierced with
openings. The outer membrane is delicate and may
be easilv destro\'ed b\' acids, friction, and the
several processes of cleaning.
When the openings or aper-
tures of this interior portion
are arranged in alternate
rows, thev assume the hex-
agonal form: when in straight
rows then the openings are
square or oblong."

Dr. Dallinger continues:

It is, howe\'er, due to Mr.

T. !•". Smith, who worked at

this subject for years, to say

that he long maintained this

\iew In Plate 1,

I'igure 1, we ha\e a photo-
graph of his, showing the
inside of a valve of P.
iiui^iildtuin magnified one
thousand se\en hundred and
fifty diameters, and exhibit-
ing the " postage stamp "
while in I'iijure 2,

fracture

■'^m^^i^^

■IGIIKK

21. The same taken at a little
different level, X 1750.

September, 1911

KNOWLEDGE.

333

in the same plate, we have the outside of P.
diifiulatiiiu, showing a different structure; and Mr.
Smith has abundant evidence of the existence of
what he has so long maintained.

'■ By using the new lens of the great aperture of
1-63, Dr. Van Heurck has produced some remark-
able photo-micrographs, which rather confirm these
general inferences than present any new data of
knowledge concerning the diatoms.'"

As it happens. Figure 6 of the plate of Dr. \'an
Heurck shows an isolated strip almost identical with

that given here in Figure 18, even to the breaking
across in one particular spot. It should be interesting
to compare the two, not onl\- the strip, but also the
edges of the fractured valve bordering the blank
spaces on each side the strip. Figure 5, of the
same plate, exhibits the hexagons magnified
ten thousand diameters, which Sir (then Mr.)
I'rank Crisp, described, on its introduction to the
Royal Microscopical Societ}-, as a remarkable
photo-micrograph. It proved subsequently to
be onlv an enlargement from the original negative.

Note.— In the first part of the atticle, on page 289, Figures 1 and 2 were inadvertently interchanged, and on page 291,

■■720" should read 1720.

CORRESPONDENCE.

OBSERVATION OF URANUS AND VESTA.
To the Editors of '" Knowledge."

Sirs, — Mr. Leonard speaks of Uranus being probably
visible to the naked eye, and in this connection I may say that
the planet is often distinctly visible without telescopic aid.
Many years ago, while pursuing meteoric observation, it was
my habit to obtain nightly glimpses of Uranus and I found it
quite possible to trace, even with unaided vision, the displace-
ment in the position of the object relatively to small stars
near. In fact I considered it an attainable feat for the
ancients to have discovered the planet with the unassisted eye
had they watched the zodiacal stars with great diligence and
compared exact positions. Indeed Vesta, as well as Uranus,
might have been recognised in this manner.

\V. F. DENNING.

THE DISTRIBUTION OF THE NIGHTINGALE.
To the Editors of "Knowledge."

Sirs, — As in the August " Knowledge " you invite
observations on the distribution of the Nightingale, I take
the liberty of sending the following : —

In the map given in "British Birds," it is shown as
numerous, or fairly so. over the greater portion of this
county. Now in the Devizes and Pewsey Vale district it is
extremely rare. My father has been in this part of the
county for thirty- five years, and the first instance of its
occurring here he has heard of was on May 3rd, 1910, when
one came to our garden and stayed for two d.ays and a night
(i.e., it was on migration).

Round Salisbury and in South Wilts generally it is a

common bird.

G. B. HONV.

THE TRUE STRUCTURE OF THE DIATOM VALVE.
To tlie Editors of " Knowledge."

Sirs, — With reference to Mr. T. F. Smith's article on the
above, it would seem a word or two is needed. At the outset
let me heartily congratulate him upon his most excellent
photographs of the valve. From one or other of them
absolutely the whole structure is laid b.are. but what at the
same time is truly astounding is the fact, that having this
actuallv before him he needs misinterpret it and head off upon
a " new structure discovery " ending up with " chains of
fibrils formed of short bars of silex arranged lengthwise
which run in pairs parallel, and each pair having larger
and narrower interspaces between, in regular succession, and
so on." All of which is totally beside the mark and quite
misleading to amateur microscopists.

These "chains of fibrils" in Pleurosigina, as well as

Mr. Smith's "pins" in Podtira scales, are as spurious to the
true structure as the Man in the Moon. One is aware that
kaleidoscopically they may be observed and even photo-
graphed, but taking his own example of sheets of transparent
paper with markings thereon placed behind one another,
although he has separated the sheets, in one photograph or
the other, he ends with placing three together (at least) under
a peculiar illumination and gives this as the true structure.
It is disappointing that with such excellent photographs the
time and patience should be expended in finally misreading
their purport and sallying forth into print to further mislead
mayhap other amateur microscopists. As I have only seen
the first portion of Mr. Smith's article published, I am
anxious to see what further discoveries he has in store for us.

F. J. W. PLASKITT.

Sirs. — By your courtesy I have received a proof of Mr.
F. J. W. Plaskitt's letter printed above, which gives me the
opportunity of replying, without the delay of another month.
For his kind reference to the excellence of my photographs I
thank him, at the same time taking exception to his strictures
on some of my work. He says, for instance: These " chains
of fibrils" in Pleiirosignia, as well as Mr. Smith's "pins" in
Pod lira scales, are as spurious to the true structure as the
" Man in the Moon." By " spurious," I suppose he means due
to diffraction effects. If so, why do they leave off' in certain
places, while at the same time there is an extended structure
immediately underneath ? Not only that, the structure I
exhibit is irregular, while diffraction effects are not. DiftVaction
effects result also from a narrow cone of illumination, while I
always work with a wide one of strictly central light.

Mr. Plaskitt says that in one or other of my photographs :
" absolutely the whole structure is laid bare " — then — " but
what at the same time is truly astonishing is the fact, that
having this actually before him he needs misinterpret it and
head oft' upon a new structure discovery " and so on.
Further ; " He ends with placing three together (at least) " —
does Mr. Plaskitt mean three layers of structure, or three
photographs ? — " under a peculiar illumination and gives this
as the true structure."

Unfortunately he does not give the numbers of the figures to
be praised, and otherwise, for guidance, leaving me quite in
the dark as to the work for which I am to be blessed and for
which to be banned. As the other part of my article appears
in this number of " Knowledge," I suppose he will now
have further exceptions to take; will Mr. Plaskitt kindly
supply the references I ask for, when I shall be pleased to
do my best towards meeting his points. I have never run
away from a discussion yet, but I naturally want to know
what I am fighting.

T. F. SMITH.

MOUNTAIN BUILDING AND ORE DEPOSITION.

By J. E. \V. RHODES, Assoc. Inst. M.E.

Of all ph3-sical features, mountains are among the
most familiar but yet the least known. Few are
ignorant of the romantic legends that cluster round
them, of the poets \\ho have sung of them, of the
nations who ha\'e defended them ; and to the
student of Histor\- the\' have e\-er had a fascination.

Figure

FlGUkH

>Si.-.l-

as the walls that have kept
race from race, and some-
times guided the destinies of
nations, .\gain, in the hard
world of to-da\' the\' are still
there, the natural frontiers of
the soldier, and the onl\-
parth' subdued obstacles of
the engineer. Yet after all
this is only a superficial \-ie\\
— the\' are something more
than view points, and if we
enquire into their structure we
shall find that every crag has
its meaning in the long stor\'
that is now revealed to us.

The first characteristic of
a mountain that we notice is
its height above its surround-
ings, not merely height, but
relative height. An uplan<l
plateau is not a mountain,
however high it be, but all
the characteristics of a true
mountain range ma\' be shewn
by a low ridge. Thus the
Malverns rise to little more

than one thousand feet, yet in structure thev are
true mountains. Of almost equal importance is
ruggedness, which is intimately associated with the
first characteristic ; for it expresses the steepness
of the mountain, that is to say, the height divided
by the horizontal extent.

Let us analyse these facts. Elevation requires
upheaval, and so a mountain chain must have been
at some time upheaved. Impressed by this truth
the earlier observers neglected all others and
attributed not merely the height but even the
details of the form of the mountain to this

cause. \"on Buch, for instance, easih' explained
the perched blocks of the Alps in this way.
\\'hen the mountain chain was thrown up, the
motion was so violent that rocks were detached,
and thrown up into the air, subsequently com-
ing to rest on the sides of the mountain.

But detailed study soon shewed that
things were not so simple. No violent
catastrophe ever threw up a comiileted
mountain chain and left it perfect. The
moulding of its form was the work of
ages and of more than one cause. And
its complicated topography is but the
expression of its no more simple archi-
Its hard and enduring rocks
have been bent, broken, and
contorted by great earth move-
ments ere the long course
of denudation sculptured its
present form.

So the primar\- origin
of mountains is in move-
ments of the earth's crust,
and it becomes of im-
portance to us to know
in what ways the earth's
crust can move, and what
effects each kind of mo\e-
uu-nt may have. Earth move-
ments are of two kinds, vi;^..

Figure J.

Figure 4.

1. \"ertical. up-and-down, or plateau building.

2. Horizontal, tangential, or mountain building.

The plateau building movements are the result of
the sinking or rising of one area relati\"ely to another.
The\- take place owing to the weight of the strata
which tend to sink in blocks into the still fluid
portion of the earth's interior, which, being molten,
is probably lighter than it, and gives rise to more or
less vertical faults or dislocations which bound the
blocks. Thus the great basaltic plateaux of the
Western Isles of Scotland have been let down b\-

336

September, 1911.

KNOWLEDGE.

337

great faults between niucli more ancient rocks. In
the deep fissures and cracks produced by this
motion huge floods of basaltic lava have welled up
while the sinking blocks of the crust sank into their
place. The type of structure thus produced is

shown in Figure 1. .. _

The mountain-building /'

movements are probably ;

caused by the gradual
contraction of the earth
as it cools in the long
course of ages. The
molten interior contracts
faster than the solid crust,
which is kept at a more
constant temperature on
account of radiation,
atmospheric circulation,
and the heat received

from the sun. From time to time, to be strictK'
accurate, at all times, the outer crust is being
drawn inwards by gravit\'. One effect of this ten-
dency has already been noticed, viz., the vertical

Figure 5

movement is to originate a series of folds such
as are shown in Figure 2, dipping in the direc-
tion of the movement and striking across the
countrv, in a direction at right angles to it. As the
mo\ement intensifies the limbs of the folds become

steeper and steeper, the
more brittle strata snap at
the crests of the folds as
in the great anticlinal fault
which marks the Pennine
Chain in Lancashire and
Yorkshire (see Figure 5).
At last the folds them-
seh-es become folded,
that is to say, their axes
bend o\-er and isoclinal
folds are produced in
which both limibs dip in
the same direction, and
the whole system of folds and faults is arched
and crumpled up. as shown in Figure 4. In
this intense crushing the limbs of folds are often
so compressed as to squeeze the core of the fold

tU^.sb

Figure 6.

slijiping downwards of some areas of the earth's

crust relativeh' to others, or plateau formation. But

since a small sphere has necessarilv a smaller area

than a larger one, it follows that the bodil\- sinking

of one portion of

the earth's crust Cambrian itra^a

squeezes together "-""'^'s"

other parts, and

this movement or

pushing aside of

parts of the crust

is horizontal or

tangential. The

pressure of this

movement is so

enormous and irresistible that the solid rocks of the

crust are folded, crumpled, and piled on top of each

other in their endeavour to occupy a less horizontal

space. It is to the piled-up masses of strata raised

in this way that we properly give the names of

mountains, and the detailed stud\' of the way in

which their component beds have moved is of

peculiar interest.

The effects produced vary according to the nature
of the strata. Igneous rocks and quartzites are
very brittle and have a great tendency to break
when folded, but soft shales can be very highly
crumpled without fractures. \\'ith the less brittle
rocks the first effect of a horizontal earth

I'IGURE 7.

bodil\- into the crest gi\ing rise to fan structure
(see Figure 5), and the component grains of the
rocks themselves are broken and drawn into
parallelism with the strike of the folds.

The extreme
brittleness of
many rocks gives
rise to another set
of features, and
since both brittle
and more or less
flexible rocks are
usually found
close together
these effects are
the recent re-
been shewn that

usually added. According to
searches of Mr. Cadell. it has
when horizontal pressure is applied to a brittle mass,
the parts nearest the pressure instead of folding,
break off and slide upwards on somewhat inclined
planes. .\s the block slides up the pressure is
brought to bear on the next portion of the mass and
another fracture or, as it is termed, minor thrust, is
produced. In this wa}- a series of thrusts is formed
dipping towards the applied pressure. At last the
huge mass of strata piled up between the pressure
and the undisturbed rocks is dri\'en forward bodily
along a genth'-inclined plane till it rests on undis-
turbed rocks. The part overlying this plane often

338

KNOWLEDGE.

September. 1911.

crumples up on account of the extreme friction, or is
crushed into powder. This major thrust, as it is
called, allows the movement to affect the hitherto
undisturbed rocks below, which in their turn become
thrust. This is illustrated in Figure 6 and Figure 7.
the latter shewing how the most ancient rocks in the
Scottish Highlands have yielded to these movements.
The chief earth mo\ements that ha\-e affected great
Britain and \\'estern Europe ma\' be gathered into
four great periods : —

1. The Pre-Cambrian. which for our present pur-
pose is unimportant and will not be dealt with.

Figure 8.

2. The Post-Silurian or Caledonian, which folded
the ancient rocks of North Wales, the Lake District,
Southern Uplands and Highlands of Scotland, and
whose folds generally strike W.S.W. to E.N.E.. so
that the movement must have come from the S.S.E.

3. The Post-Carboniferous, or Hercynian. which
folded the Coal Measures and included two separate
movements, one of which produced most marked
effects in the South and the other in the North of
England. The Armorican movement came from the
South and crumpled the strata in the South and
West of England into a range of mountains forming
part of the great Armorican-\'ariscan chain, which
then almost ranged across Europe. Though its
effects are concealed from view in Eastern England
by a mantle of newer rocks, it is well shewn in
Devon, Cornwall and S. \\'ales.

The other Post-Carboniferous movement is called
the Hercynian movement, and uplifted the Pennine
Chain, forming great folds running North and
South in the North of England.

4. The fourth great series of movements raised the
chalk and converted it into land. These movements
continued until the middle of the Tertiary period,
and in Britain, especially in the Western Isles of
Scotland, were of a plateau-building t)-pe. In
Switzerland, however, great mountain building
stresses were set up and resulted in the formation
of the Alps.

It must not be imagined, how e\'er, that the highest
peaks of any mountain range have received most
uplift, and that the valleys necessarily lie in the
troughs of the folds. Such is far from the case, for
the uplift has always been so slow that the wasting
action of air and water has had enormous effects,
and the effects of the earth movements are only
indirectly responsible for the scenery. The eleva-
ticm of the .\lps as a whole is due to earth move-
ment ; its individual peaks and vallej'S are due to the
relative hardnesses of the diverse rocks of which
they are composed.

In the stud\' of mountain chains two things have
long been noticed and as will now be seen have more
than a practical interest. They are the abundance
of mineral veins and of granitic and other igneous
rocks. .\s has been mentioned before, igneous rocks
also characterise plateaux, but they occur in a
markedh- different manner. If we examine the
British metalliferous areas we shall find that they
have all suffered from the mountain-building move-
ments of the Caledonian and Hercynian, the great
plateau regions of N.E. Ireland and the ^^'estern
Isles of Scotland being devoid of mineral veins. It
is also remarkable that most of the veins occupy
fissures which appear to be due to the Hercynian and
Armorican movements : onlv in a few parts do they
appear to be Caledonian. To explain these
phenomena it will be necessary to take a glance at
the modern theories of the relationship of igneous
rocks and mineral veins.

According to modern theories, beneath the solid
crust of the earth lies a magma composed of fused
rocks. Chemically it is composed, in the neighbour-
hood of the crust at anv rate, of silicates and
sulphides, which at the enormous temperature and
pressure which there obtain are probably mixed
together, although anv lowering of temperature and
pressure would cause them to separate into two
layers.

The enormous i)ressure of the overlving rock tends
to make this magma rise up through any cracks that
may be present in the crust and dissolve large
cavities in it. B\- so doing it draws nearer the
surface and the sulphides and silicates separate into
la}-ers, the silicates at the top and the sulphides at
the bottom. The fractures of the rocks caused by
the great earth movements afford a ready means of
escape, and in man\' cases the powerful uplifting

>'\

^^\T^mi \ "y^'

nfA

^\^^y>^

h-^S^J/F^

W(

'am

^W^

^

Figure 9.

action of the ascending rock has important effects.
Thus a body of molten rock ascending a fissure may
meet an impervious bed of rock and spread out as a
sheet or sill, or arch up the strata to form a laccolite
or occupy the core of a fold to form a phacolite.
(See Figures 8 and 9.)

Since the silicate or rock-forming magma floats on
the top we naturalK' expect that the formation of
igneous rocks will precede the production of mineral
veins, and when we come to examine the actual
distribution of the ores we find that this is always
the case. The tin veins of Cornwall are later than
the granite, although certainly originally derived
from the same magma, whilst the sulphide ores of
copper in the same district are later still. In the
same way the phosphate (apatite)) deposits of
Norwa)' represent the last stages in the consolida-

September, 1911.

KNOWLEDGE.

339

tion of the great masses of gabbro, and wherever the
gabbro is pierced bv the veins a very pecuHar altera-
tion is produced in the gabbro which shows that it
has been affected by heated waters containing Chlo-
rine, a characteristic constituent of the ore apatite.
We have thus traced mountain building, the
formation of igneous rocks, and the production of
mineral \eins, back to the same source — the great
crustal movements caused bv the contraction of the
cooling earth. Despite their enormous effects, these

movements are so slow that the}- would escape
notice altogether but for those surface symptoms,
earthquakes and volcanoes, which remind us that
there are jolts in the evenness of an otherwise
imperceptible movement. Movements that have
begun long before historical times are still un-
finished. The Himalayas are even no-w being folded
over towards the great plain of India, and the far
more ancient Highlands of Scotland are still moving
feeblv along the old faults.

QUERIES.

Readers are invited to send in Onestions and to ansic-er the Queries ichich are printed here.

REPLIES.

46. BIBLE .A.STRONOMY. — I do not know in what spirit
J.W.A. has written this query. The sudden standing still of
any of the heavenly bodies (apart from collision) is obviously
of the nature of a miracle, i.e., the operation of some special
agency over and above the ordinary known forces. We clearly
do not know its mode of action, so cannot introduce it into
our mathematical analysis. But it would obviously be futile to
leave out of account the action of this transcendent power,
and yet to expect to obtain the true " effect on our planet and
others of the system," on the assumption that only the known
forces were acting. This is, however, the inconsistent assump-
tion that J.W.A. appears to contemplate. Many think that the
poetical and somewhat indefinite terms of the narrative can be
sufficiently explained without assuming an actual change in
the motions of the heavenly bodies. For example, he will find
in Mr. E. W. Maunder's "The Astronomy of the Bible," the
suggestion that the miracle was really the giving of unusual
strength and endurance to the pursuing army, so that they
made an afternoon march which would normally be deemed
impossible, and inferred that the day had been lengthened.

A. C. D. Crommelin.

47. GR.W'lT'i'. — I think it is sufficient to simply say that it
is gravitv, and not the atmosphere, which prevents our falling

°fft*^^^^^'h- A. C. D. Crommelin-.

47. GRA\'ITV. — The statement made by your correspon-
dent's friend. " That gravity is now rather discredited by
scientific men " is quite incorrect.

The theory that '" We do not tumble off the earth because it
is surrounded by the atmosphere" is .absurd on the face of it.
seeing that the air, like every other substance, has weight and
actually tends to buoy us up. Humphrev Wilson.

QUESTIONS.

49. POLAR PHENOMENA.— I am thankful to the Rev.
Mr. Davidson for enlightening me. in the February number of
your journal, on some points of Polar Phenomena which had
troubled me for some time past. May I take the liberty of
troubling Mr. Davidson again, or any of your readers who may
take interest in the matter, to enlighten me on the following
points also.

1. An Indian author in his calendar for S6i- of latitude gives
twenty-four to twenty-three days as the period of continuous
long dawn, seventeen to eighteen days as the period of alter-
nation of twilight and sun, and one hundred and sixty-nine to
one hundred and seventy-one days as the period of continuous
long day. Are these figures strictly correct, or may I assume
that in actual observation they may vary slightly ? I want a

latitude which would give twenty-four days for the long dawn,
sixteen days for the period of alternation and one hundred and
seventy-one days for the long day. Will 86^° suffice for my
purpose or shall I have to assume it to lie between 864° and
87°— say, at 86^° ?

2. What is the exact manner in which the sun's disc is
rendered visible during the sixteen days-long period of alter-
nation ? I am told that the period of alternation begins when
the South declination is 4° 20', and ends when the North
declination is 4° 20'. Shall I be wrong in imagining that the
phenomena of sunrise during the alternation period occur as
follows ? On the first day the sunshine will last for about
one-and-a-half hours only, and the maximum portion of the
sun's disc visible that day (at noon) will be about one-sixteenth
of the whole. On the second day about a two-sixteenths portion
of the disc will rise into %iew, and the day will last for nearly
three hours. On the third day three-sixteenths, on the fourth
four-sixteenths and so on, till at noon on the sixteenth day,
the whole disc will have emerged into view, standing just
above the line of the horizon. Of course, the stay of the sun
above the horizon will not be in the e.xact arithmetical pro-
gression as I have stated above, but practically the progres-
sion may be assumed to be so, as the daily variation will be
slight. I wish to know if the phenomena occur as assumed
above, or whether the complete disc of the sun will be visible
at noon, for some days during this period of sixteen days.

3. If the first day of this alternation period falls on the
eighth day of the dark half of a certain month, will not
the Vernal equinoctial colure occur on the new moon day
following or on the first day of the bright half of the next
month ? And also, may not such colure be assumed to occur
at the very beginnings of a new (lunar) constellation ? A certain
Vedic passage says that the new year's day falls on the eighth
day of the dark half of the month connected with the constella-
tion Magha. which has been identified with Regulus (129').
Assuming this day to be the first day of the sixteen days-long
alternation period, shall I be right in taking the equinoctial
colure to occur in (Delta) Leonis (139^ 5S') ?

I shall thank any one of your readers if they will kindly
enlighten me on the above-mentioned points.

Baroda.

R.K.P.

50. RADIO-ACTIVITY.— Would any of your readers
inform me concerning the following questions for which I have
not been able as yet to find an answer.

(1) Is it definitely proved that the a particles of a radio-
active body are helium ? Is this transformation ?

(2) What is the exact nature of X rays ? are they identical
with and the same as the y rays of radio-active bodies ?

(3) What is the cause of the glow of the glowworm ?

H. Sinclair Tait.

A NEW TABLE FOR PRACTICAL MICROSCOPY.

Bv The Rf.v. F. C. LAMISERT. .M.A.. l-.K.l'.S.

Sooner or later everN- user of a microscope ex-
periences the inconvenience of the usual height
(30 inches) of a writing table when it is required
for a microscope witii the tube in a vertical position.
One feels the need either of a lower table, or an extra-

1-IGURE 1.

high seated chair. To meet
this difficulty, some time ago
I designed a table and had
it made by a local cabinet
maker. One or two subse-
quent and trifling alterations
have yielded me a perfectK-
satisfactorv piece of furni-
ture, which I propose to
illustrate now somewhat
fully, b\- means of photo-
graphs, so that an\- working
carpenter should be able
to repeat the apparatus
in design, and modify its
dimensions to suit the needs
of his employer, bv com-
paring the various illustra-
tions one with another.

The photograjihs had to
be taken somewhat hur-
riedly in a quite small room,
camera without a swing back.

llGURE

sized Smith-Premier t\'pewriter which is here
stored out of the w a\- w hen not in use. .\bove this is
apparenth' a handleless drawer, hereinafter explained.
On our right is a knob by which one pulls out a flat
slide which gives extra table room. Below this are
two drawers, the upper, two and a quarter inches,
the lower four and a half inches deep inside. The
upper holds slips, dissecting tools and so on. The
lower is nested with card divisions for bottles.
Below, on the right, is a cupboard sixteen and a half
inches high — amph' tall enough to take any <irdinary
full-sized microscope case. .\t the back of this
cupboard are two narrow shelves for sundries, larger
bottles and so on. One of m\' difficulties was in
obtaining sufficienth' small and low castors, of which
six are needed.

Figure 2 shows the end flap raised and draw-
slide partly pulled forward.

Figure :> shows that the table top is cut and
joined b\' " counter hinges." The left-hand part
is folded flat over the right-hand portion of the

table top. This folded-over
l)art forms an excellent rest
for bottles and sundries. To
our left is seen a box-like
recess.

In Figure 4 \se see that
the front side of this box-
hke arrangement has been
rcmo\ed and is laid on the
table top. Behind one end is
put a post card to act as back-
ground, and show the tongued
end of this piece. We here
also see the groove into which
tliis tongued end slides.

In Figure 5 we see the
microscope resting on the
flat top above the typewriter
shelf, four inches lower than
the writing table top — i.e..
twent\-six inches from the

and with a hand
These limitations
will account for an obvious but slight distortion
effect, which gives the table a tilted forward and
enlarged top appearance. Some apologies are

needed for the dust sheet background. Figure 1
shows a full face view of the table when in use for
writing, and so on. Hei^'ht from floor to top, including
castors, thirty inches, length thirty-six inches, width
twenty-four inches. The end flap shown hanging
down on our right gives another eight inches length
when it is raised on its side folding bracket. An
ordinar}- half sheet blotting pad on the top gives one
an idea of scale size. In the knee-hole part to the
left is a shelf just wide enough to take a full-

I-'ic.fRi;

340

Septemukr, 1911.

KNOWLEDGE.

341

ground. This I find quite high enough for vertical

tube work. Indeed, perhaps twenty-five inches

would be a more generally convenient height for

an ordinary chair and sitter.

This sliding part stows con- '

veniently out of the way ;

along the edge of the recess.

The open cupboard shows

the microscope case also out

of one's wav.

Before winding up, per-
haps I ina\' mention two
very simple contri\-ances.
which I ha\e long used
with great convenience.

Figure 6 shows a straight
bit of wood about a foot
long, two inches wide and
one inch thick. In it are a
number of circular holes
large enough to take the

(c)
id)

Another glass rod with knob end for applying

a larger drop.
A handled shar[)-pointed knife.

(e) A curved needle for
' tearing out tissues.

(/) A double-edged spear

knife.
To save repetition the
parts in all the figures are
uniformly lettered.
A Typewriter shelf.
H and C left and right hand

portions of hinged top.
D Draw slide.
E Hinged flap snpported by

hinged side bracket.
V Sliding front of depressed

table top.
G and H Tongue and groove of F
J Objective holder.
K Upper drawer.
L Lower drawer.
iM Cupboard.

Figure 5.

immersion oil bottle,

and a number of brass

cases of objectives. A

strip of card glued on

the bottom of the wood

prevents the things

slipping about when it

is moved. It is kept

out of the way and \et

convenientlyathandin

the recess (Figure 3).
Figure 7. .\ stiff

card shallow box-lid

in which are cut a

number of nicks for

holding tools and pre-
venting them rolling about.

special favourites : —

(a) Forceps with slide clam
(/)) Glass rod with drawn
tiny knob for appl
when dissecting.

Figure 7.
Here arc half-a-dozen

out slender point and
ving reagents locally

Figure 6.

The lower le\el top
arrangement on which
the microscope rests
(Figure 5), also serves
admirabl}' to hold my
tvpewriter at a con-
venient height. The
folded over part B
( Figure 3) is then very
convenient for writing,
corrections, and so on.
The back ends and
door are all panelled:
the back and ends
have also styles (Fig-
ure 2). The work
throughout is in solid oak and darkened by ammonia
fuming. The carpenter's cost, not including castors,
locks and keys, and brass handles, was four guineas.
Doubtless, he would repeat at or about the same
price. The workmanship is excellent. I send the
carpenter's address to the Editor.

CLUSTERS AND NEBULAE.

Bv F. W. HENKEL, B.A., F.R.A.S.

Moke than two thousand years ago the Greek
philosophers, Democritus and Anaxagoras assured
theircountrvmen that the luminous circle of the Milky
^^'a^■ consisted of nothing but dense masses of
stars too small and too close together to be seen
separately. The former, sometimes known as the
"Laughing Philosopher"" of Greece, also entertained
some equally remarkable vie\\s on other subjects :
the atomic theory, the nature of the sun and stars,
and so on, many of which have been \-eritied by
later investigation. In addition to the Milky Way
itself there are to be found, scattered all over the
sky, luminous patches of cloud-like material, stellar
groups or " nebulae," as some of them are called.
Many of these are known to consist, like the Milky
Way itself, of numbers of stars too near together to
be separately visible to the unaided eye except in a
few cases. The well-known Pleiades group in
Taurus is an example. There are to be seen by
the eye from seven to twelve stars close together,
the number varying according to the keenness of
sight of the observer and the state of the sky. With
the help of the smallest telescope this number is
increased to about one hundred, whilst the large
telescopes and photographic ap[)liances of modern
astronomy have enabled us to detect the presence
of a vet greater number of stars as well as streaks
and wisps of nebulosity surrounding and enveloping
most of the region. The Hyades cluster is situated
close bv in the sky, and not far off is the "Praesepe"'
in Cancer, which seen as a cloudy patch, becomes
resolved into a swarm of stars, whence the name
Praesepe (Beehive).

Other well-known clusters are those known as
13 M Herculis, not very far from the " apex "" of the
Sun's wa\-. often considered the finest in the
Northern Hemisphere, the cluster surrounding
the star (o Centauri (see plate), the group in
the "sword handle"' of Perseus, the beautiful
cluster M Canum Venaticorum (the Hunting
Dogs), the cluster M 14 Ophiuchi. and so on.
Some of these clusters are shown to be such
by the help of very moderate telescopes, though they
are better seen with larger instruments, others
require more powerful optical aid, whilst yet others
have never been resolved into stars, though on
other grounds we have reasons for suspecting their
" resolvabilitv." as distinct from what are now
known as '" true "" nebulae. Since, as we have said,
most clusters, if visible at all to the unaided eye,
appear to it as cloud-like mist\- objects or "nebulae,"
and are resolved into separate stars by a greater or
less application of telescopic power, it was at one
time thought that all such objects were of a similar
nature, the difference between different clusters arising

from the var\ing si/e of their members ortheirdiffering
distances from our system. ^^' henever a new or more
powerful telescope was applied numbers of these
nebulae or cloud-like objects (Latin— «»/je.s, a cloud)
were " resolved "" into separate stars, though some,
such as the nebula of Orion and the great nebula of
Andromeda, showed no signs of such resolvability.
However, the great reflector of Lord Rosse being
applied to the former, it was reported that this
instrument had at last resolved the nebula, but this
was a mistake, for as we shall see, no telescope ever
can or will resolve it, since it is not composed of stars,
but is of an entirely distinct and different nature.
Fiftv or sixty years ago, however, this idea of the re-
solvabilitv of all nebulae into clusters was generally
entertained. It was thought that they were remote
clusters or " island universes,"" lying far beyond the
SN'stem to which our own Sun belongs (the great
Milky Wa\', or Galaxv), so inconceivably remote that
light, though travelling at the enormous speed of
over 186,000 miles per second, requires many
thousands of 3-ears to reach us from them, and many
mav have ceased to exist ages ago, and yet it \s ill be
many ages hence before we become aware of their
extinction. The work of Herschel and later investi-
gators, showing the intimate connection between the
distribution of the clusters and nebulae and the
position of the Milky Way generally, has thrown
doubt upon the validity of such views, though many
popular writers have made these ideas generally
known to the non-scientific public.

The memorable and systematic exploration of the
heavens, with instruments constructed by himself
and of far greater power than any previously used
bv astronomers, has immortalized the name of Sir
\Villiam Herschel, and it is this, perhaps, more
than the discovery of a new planet in the Solar
system, which was his greatest contribution to our
Science. Previously to his day the number of
clusters and nebulae known did not exceed about
one hundred and fifty or so, many of which were
detected by the famous French astronomer Messier,*
known as the " comet ferret " from his diligent
search for those bodies, whose ill-defined and often
mist\- appearance is not unlike that of a nebula, and
indeed a comet has been not inaptly termed " a
wandering nebula " for more than one reason. Sir
John Herschel extended his father's work into the
Southern hemisphere, staying for several years at
Feldhausen, near Cape Town, and completely sur-
veying the whole sky. In 1864, he published a
catalogue of five thousand and seventy - nine
nebulae and clusters, a great part of which had
not been previoush" located hv other observers.
A supplement containing afiout a thousand more

The letter M before the name of a nebula or cluster indicates that it is one uiiich was included in iMessier's catalogue.

i-{2

From a Photograph bv Curtis.

By /.If courtesy of Professor S,\

The Cluster w Centauri.

343

344

KNOWLEDGE.

September, 1911.

of these objects was published by Dr. Dreyer after
the death of Sir John HerscheL and additional lists
containing objects discovered by photograpliy and
in other ways have, perhaps, brought up the number
to double that contained in Herschel"s catalogue.
The most remarkable discovery in stellar, or perhaps
\\e had better say sidereal, astronomy during the last
half-century is that of the existence of vast numbers
of spiral or " whirlpool "* nebulae. Only a \'ery few
of these objects had been previously known, the
first having been detected by Lord Kosse, about
1840, with the help of his great reflector, which
showed the spiral form of the great nebula in Canum
Venaticorum and others previously regarded as ring
formed or annular.

Sir \\'illiam Herschel divided these objects into —
(1) Clusters of stars in which the stars are easily
distinguishable : these are again subdivided into
^/o6/(/t7r and irregularclusters. (2) Resolvable nebulae
or such as excite the suspicion that the_\- consist
of stars, and which any increase of optical power
may be expected to resolve into distinct stars.
(3) Nebulae, properly so called, in which there is no
appearance whatever of resolvabilit}' ; these again
were subdivided into subordinate classes according to
their brightness and size, and so on. (4) Planetary
Nebulae, (5) Stellar Nebulae, and (6) Nebulous
stars.

Long previousK' to Herschel's dux. Hallex' and
other earlier discoverers of nebulae had followed the
speculations of some philosophical w ritcrs in postu-
lating the existence of a primitive elementary form
of luminous sidereal matter, (Halle\-. Philosophical
Transactions. \'ol. X.\L\. page J90. ct sci/.K but
it was mainl\- as a result of his extensive observa-
tions that Sir William Herschel himself was led to
consider the consequences of a gradual subsidence
and condensation of such matter into more or less
regular spherical or spheroidal forms denser tow ards
the centre than at the circumference. Laplace's
well-known nebular hypothesis, worked up hv him
from the previous suggestions of Kant. \\'right.
Swedenborg, and others, also brought into [iromi-
nence this idea of " nebulous matter " nt a nature
distinct from ordinary solid or fluid substance such
as we are familiar with on our planet.

The application of the spectroscope to Astronom\-.
about the year 1860, threw a flood of light upon
subjects which had been thought to be bevond the
powder of the mind of man to discover, such as the
chemical nature and ph}-sical condition of the
heavenh' bodies and enabled us to draw the real
distinction between true nebulae and ap[)arent
nebulae, or remote and condensed clusters. Newton
in his " Optics " relates that he once decided to "trx
the celebrated experiment of the colours." Admitting
sunlight through a small opening into a darkened
room, if allowed to fall normalh' on a white screen it
produces a round white spot, which is an image of the
sun. If now we introduce a prism or triangular piece
of glass, with its edge downwards, in the path of the
beam, the latter will be deflected upwards, and the

image on the screen will be no longer white
but coloured, a man\- hued band, showing the
" colours of the rainbow." The i)rism. in fact, will
have effected an analysis of the light. White light
(sunlight) is composed of a mixture of different
colours, and these on passing through the prism are
deviated to a greater or less degree, the violet ra}-s
most refracted and the red least so. By employing
a \'er\- narrow slit cUid a number of prisms (or a
diftVaction gratmg) a pure spectrum or coloured band
of considerable length, in which the colours are well
separated, is obtained. By such means Wollaston,
and after him Frauenhofer, showed that the
■■ spectrum " gi\^en by sunlight is not quite con-
tinuous, but crossed b\' a number of fine dark lines
or \-acant spaces, if the slit is illuminated by a
gas flame or lamp such lines are not seen, but a
continuous spectrum is obtained, giving the colours
red, orange, vellow, green, blue (indigo) and x'iolet,
the so-called seven colours of the rainbow. Thus
the dark lines are not characteristic of light in
general, but only of sunlight. By special means
it was shown that the brighter stars, too, gave spectra
containing svstems of dark lines somewhat similar
to those given bv sunlight, but with differences for
different stars.

Passing over various stages in which the meaning
of these lines, known universalh" as the Erauenhofer
lines, was gradually unfolded, we come to the work
of Kirchhoff and Bunsen. They showed that a con-
tinuous spectrum is given by every incandescent body
whose molecules are so entangled as to be unable to
\ibrate freely ; in other words, by solids, liquids and
gases under high pressure. A gaseous substance,
under low pressure, gives a discontinuous spectrum,
containing only a few briglnt lines, and these lines
are characteristic for each elementary substance, and
also for some compounds. \ gaseous substance,
when cooler, absorbs from white light passing
through it, precisely those rays which itself emits
when hot. Thus the spectrum of white light,
after passing through sodium \apour. exhibits
two distinctive dark lines in the yellow, whilst
inciuulescent sodium emits a yellow light, which,
when examined by the spectroscope, is found
to be of just that refrangibilit>-. Thus it was
discovered that somewhere between the Sun's
luminous surface and the earth, there are a number
of vajiours of well-known elements, which form
the ■■ dark " Frauenhofer lines. Applying the
spectroscope to the nebulae and clusters, a matter of
some difficulty owing to the faintness of their light,
the late Sir William Huggins. aptly named by
Proctor the " Herschel of Spectroscopy," found that
man\- of the former bodies gave spectra consisting
of five or six bright lines, indicating the presence of
hydrogen, magnesium, and nebulium (?) under low-
pressure, in a state of great rarefaction.

.Some, such as the great nebula of .Andromeda,
give a continuous spectrum unmarked by lines or
bands whether bright or dark. It is possible these
ma\' consist of more condensed gases, but this is by

September, 1911.

KNOWLEDGE.

345

no means certain. Clusters and resoh'able nebulae
give spectra similar to those given by the stars
showing their starlike nature, whilst the irresolvable
nebulae, as we have just said, give either bright
lines or continuous characterless spectra. Thus a
real distinction of a physical nature may be drawn
between the different classes of these objects. (Dr.
Path, however, is of opinion that, notwithstanding
what has been just stated. '" no spiral nebula has a
realK' continuous spectrum." that the continuous
spectrum of the Andromeda nebula, or at least
that of its central portions, is given b}- " an
unresolved star cluster consisting of stars mainly
of the solar type.") Of late years photograph}- has
been successfullv applied to spectroscopic purposes
and spectrograms of many of the brighter stars and
clusters, and nebulae, have been obtained. .Amongst
remarkable clusters and groups of stars with com-
munity of proper motion, which seem to be con-
nected, in some as \et unknown wa'-, b\" a force
acting far more powerfully and at greater distances
than gravitation, in addition to the Pleiades which
we ha\e already discussed (see also a paper by the
present writer in " Knowledge" for July, 1907).
ma\" be mentioned the " tive stars " in Ursa Major,
which were pointed out by the late Mr. Proctor about
fort\- \"ears ago, as well as by Flammarion and others"
and also the Taurus cluster investigated by Professor
Lewis Boss. Drs. Ludendorff and Hertzsprung ha\e
shown that Sirius, the brightest star in our sky, is
a member of a famih' which includes (besides the
five stars, /3, y, o, e and <,' Ursae Majoris), also /3
Aurigae, 37 Ursae Majoris, o Leonis and a Coronae
Borealis. These ten stars appear to drift together,
Iving approximately in one plane and nearly in a
right line. In the Asfroiwniical Journal, Number
604, Professor Lewis Boss has discussed a moving
cluster in Taurus, consisting of man\- of the Hyades.
For more than twenty-five years he has been investi-
gating their motions and found these '" nearly
identical," at least fortv whose directions of motion
converge towards a common though \erv distant
point, " at which their apparent velocities will
enable them to arrive almost simultaneoush' after
the lapse of some sixty-five million years ! " At
present this " cluster " is spread over a total area
of 15° but is somewhat condensed towards the
centre.

It has been estimated that the average velocit\' of
the entire cluster is about forty-six kilometres (sa\'
under thirty milesi per second, and the '"average"
parallax 0"-025 (Kiistner) giving a corresponding
distance from our system of eight hundred billions
of miles, thirty times that of the nearest star, .\lpha
Centauri. As a result of Professor Boss's work in
another direction, Mr. Eddington. of Greenwich, has
given an account of a " Moving Cluster of Stars of
the Orion Type in Perseus." Sixteen stars, Iving
between R.A."3" IP" and 5'' 15'" Dec. +42" to +58".

share very nearly the same motion, both as regards
magnitude and direction, and thus form a group
similar in character to those above mentioned. Their
magnitudes range from 2-9 (e Persei) to 6-4,
and the mean " i)ro[)er motion " is about 4" per
centurw

On clusters of stars in general, and especialh" on
the regular globular clusters it may not be without
interest to notice the remarks of the late Sir John
Herschel. who was the highest authorit}' on such
matters, and who had himself observed more of these
objects than any other astronomer of his day. " We
can hardl}- look upon such a group ... as not
forming a system of a peculiar and definite character.
Their round figure clearh' indicates the existence of
some general bond of union in the nature of an
attractive force : and in manv of them there is an
evident acceleration in the rate of condensation as w'e
approach the centre, which is not referable to a
merely uniform distribution of equi-distant stars
through a globular space, but marks an intrinsic
density in their state of aggregation, greater in the
centre than at the surface of the mass." The
stability of such a s\-stem " without a rotator\-
motion and centrifugal force," is scarcely con-
ceivable, but if we suppose a globular space
filled with equal, and very numerous stars,
attracting one another according to the gravi-
tation law, an}- one of these will be urged b\'
a resultant force directed towards the centre of the
sphere and proportional to its distance therefrom
(law of direct distance, Newton). Under such a
resultant force each individual star would describe a
jierfect ellipse about the centre of the s\-stem,
no matter in what plane it might lie. or in what
direction it might be moving. Thus it would not
be necessar}- that the cluster should rotate as
a mass around a single axis. Each ellipse
described by the separate members would remain
unchanged in form and dimensions, and all
would be described in one common period, so that
at the end of each such period every member of the
system would be in exacth' the same position with
regard to ever}' other, and would run the same round
for an indefinite succession of ages. Such a system,
whose members were sufficientl\- distant from one
another so that their orbits did not intersect, might
exist and realise a state of abstract and ideal harmony,
transcending even the harmonious and stable con-
ditions of our own Solar system, w ithout any pre-
ponderating "'Central Sun." However, it is pirobable
that such a condition of affairs is but rare in the
sidereal spaces ; though man}- almost perfecth-
globular clusters are known, others are of a more or
less oval outline, and }-et others of irregular figure.
These latter are also less definite in outline, so that
it is not always eas}' to sa}- w-here they terminate,
and the\" are not often condensed towards a
centre. B}- far the greater proportion are situated

■■' This community of proper motion was named by Proctor " stardrift." The stars appear not only to be moving
together, but their chemical constitution as revealed by the spectroscope is similar.

346

KNOWLEDGE.

September, 1911.

in or near the Milk\ W'av. a fact which led Sir \\'.
Herschel, quite earlv in his career, to infer the
existence of a ckistering power, akin to gravitation,
which is gradually breaking up the Galaxy, and
has already given that "great arch of light, the
aspect of a series of clusters rather than that of a
uniform band of milk\- light." Professor See. in his
great work " Researches on the Evolution of Stellar
Sx'stems "■ (\'ol. ID. has however, pointed out the
important effect of the uni\'ersally diffused cosmical
dust, which acts everywhere as a resisting medium,
so that " the Milk^ \\'a\' may have been alw ays more
or less aggregated into clusters, which have simply
grown denser or become more dispersed with the
flight of ages." If these clusters arose from the
condensation of nebulous material, and this diffused

" cosmical dust " acts everywhere, it follows
ncii'ssarih- that all clusters will, in course of time,
become more dense and more nearly globular, unless
the aggregations thus going on are dispersed by the
action of external forces due to other clusters.
Space will not permit our pursuing this interesting
subject further, but it must be fairly exndent that the
study of the nature and conditions of formation,
growtli and deca\- of these objects is one of the
grandest with which the human mind can be
emplo\'ed. \\"e owe much to the patient labours of
■■ self den\ing men of science " but more lies for the
future to unravel, and as there appears to be neither
end nor beginning to the Universe of God, so also
must we believe that its complete comprehension
w ill for ever transcend the finite mind of man.

SOLAR DISTURBAXXES DURING JULY, iqii.

By FRANK C. DENNETT.

There has been a very slight increase m the amount of solar
disturbance during July, but on four days (6th, 11th, 25th and
26th) no trace of activity was visible, bright nor dark, and on
sixteen days (5th, 7th— 10th, 17th— 24th, 27th. 2Sth and Jlst)
only taeniae could be seen. The longitude of the central
meridian at noon on July 1st was 65 41'.

No. 27. — When first seen on the afternoon of J ul\' 1st it was
a single pore, but next day there were three forming a long
triangle 25.000 miles in length. It was not seen on the 3rd.
but a pore showed on the 4th.

No. 28. — A solitary spotlet only seen on the 2nd and 3rd.
No. 28a. — A group of four pores 23,000 miles in length,
forming two pairs, only seen on the 4th.

No. 29. — Two spotlets, the western largest and accompanied
by two pores, were visilj e on the 12th. During the next day
considerable Iteration took place in the group, by the afternoon
the rear spot had enlarged considerably and thrown forward a
sort of tail which broke into a line of small umbrae, having in
front of them a small triangle of pores. On the 14th the rear
spot was about 5,000 miles in diameter, with a curve of pores on
the northern side and line of pores in front, having a total length
of 52,000 miles. On the 15th its length was unchanged but
its members were shrinking, and on the 16th onlv the hinder-

most spot was seen cut in halves by a bridge, with a tiny
pore to the south. Not seen after, except its faculic remains
near the western limb on the 19th, 20th and 21st.

No. 30. — A group of three pores, one very tiny, 18.000 miles in
length, on the afternoon of the 29th, but on the 30th only two
minute pores seen close together, and not seen after.

No. 31. — A pore visible on the northern border of a bright
faculic disturbance on the 30th. but not observed after.

On the afternoon of July 8th. a very pretty prominence
eruption was witnessed, though on a very small scale. In
adjusting the position circle of the spectroscope, a bright little
bead was noticed only S' west of the north pole. Within a
very few minutes it threw up a fine needle of light which
slightly expanded, then bent over polewards and began
drifting off as clouds. The positions of the other prominences
around the limb were measured, then on returning to the same
point only a little bead of light remained. The position of the
bead was measured at 5.45 p.m.. and the observation was
completed at 6.10, so that the eruption could only have
occupied a few minutes.

Our chart is constructed from the combined observations of
Messrs. John McHarg, E. E. Peacock, and V. C. Deiniett.

DAY OF JULY, 19 ii.

^ A SI 3, pO g p9 I, f8 "p ?6 25 if. 2^ Sf 2,\ 2,0 19 16 1^ Ij5 15 l-t Ip I? rl 10 9 B 7 ^

t7

30

E"

W

ISJi.

.0 so <.l) 50 60 70 80 90 100 110 120 150 l«) ISO 160 170 180 M 2O0 ,'10 220 ZX 2+0 250 !6C 270 280 290 500 JIO 320 3J0 3*0 350 «0

NOTES.

ASTRONOMY.

By A. C. D. Crommelin. B.A.. D.Sc, F.K.A.S.

BOTAXV

Bv Prokessor F. Cavers. D.Sc F.L.S.

Being at the seaside and away from all sources of
astronomical information or reference my notes this month
are very brief.

EN'CKE'S COMET was found on the last day of July, by
M. Gonnessiat, at Algiers. Owing to its unfavourable position
there were some apprehensions that it might escape detection
at this return, and thereby break a remarkable record of
visibility at every return since 1819. Perihelion is passed
about August 20th. After the observations of this return
have been discussed, it will be possible to discriminate between
Professor Backlund's two hypotheses to explain its recent
movements, viz. : II) that it suffered a sudden change in its
rate of acceleration about 1905, (2) that the mass of Mercury
which he had previously derived is sensibly in error. Encke's
comet affords the best way of determining the mass of
Mercury, since the two bodies are periodically very near
together. None of the planets are sufficiently perturbed by
Mercury to give its mass with any accuracy.

BROOKS' COMET.— After last month's notes were
written, the veteran comet discoverer, Mr. \V. Brooks, of
Geneva, U.S.A., discovered a faint comet, which is likely to
brighten into naked eye visibility before next November, when
it makes a fairly near approach to the earth. The earth,
about September 3rd, will pass through the point occupied by
Kiess' comet four weeks earlier. There is a possibility of a
meteor shower at that date, if the comet has a meteoric
appendage following in its wake, as some comets are knoun to
have.

SOLUTIONS TO MR. BARTRUM'S QUERIES (page
311). — The answer to the first query. ;v the iUuniination of
Venus, is that his law of illumination, varying as the cosine of
the angle of incidence, only holds for smooth spheres, which
the planets are not. Even tiny inequalities on the surface, far
too small to be discerned from other planets, suffice to give
an altogether different law of illumination.

The most casual glance at the Moon suffices to show that
the illumination at the terminator is very different from zero,
which it would be on his hypothesis. The actual law is doubt-
less a very complicated one. but empirical formulae have been
given for representing observed facts with fair approximation.
The formula used in the Xautical Almanac for finding when
Venus is brightest is avowedly only a rough approximation, and
does not profess to accurately represent the facts of nature.
It is only used because the phenomenon is not considered a
sufficiently important one to call for a refined investigation ;
indeed it would be practically impossible to determine
by observation the average slope of the small inequalities on
its surface, which would be one of the necessary data of an
accurate solution. Re his second query, the phrase " mean
distance," if used without further qualification, is always
taken to mean the semi-major axis of the elliptical orbit.
If any one desires to use the phrase in one of the other
meanings which he indicates, it is necessary to specially state
the fact.

I prefer to postpone his third query till next month. I
think I see the fallacy involved, but it is easy to make mistakes
in such problems. In any case, he has succeeded in finding a
neat little astronomical catch.

PRE-GLACIAL FLORA OF BRITAIN.— In a recent
paper on the plant remains found in the Pre-glacial deposits of
Norfolk and Suffolk. Clement Reid ijoiini. Linn. Soc.) gives
a list, with notes, of the Fre-glacial species of British flowering
plants now known, numbering one hundred and fifty. The
plants described grew in the small stream channels of a large
river, probably the Rhine, and in the adjoining wet meadows
or in moist woods close at hand. The flora of Norfolk and
Suftblk as a whole has altered very little in the many thousands
of years since these beds were formed, although it was driven
out by the cold of the Glacial Period and returned later.
A certam number of exotic species are recorded, however,
these including three species of Ranunculus, a. water lily, the
water-nut iTrapa uatansK the spruce fir iPicea c.xcclsa),
and Naias niitior. The southern element in the Cromer
flora is therefore greater than was formerly supposed, and it
apparently includes several extinct species. These pre-
glacial plants suggest climatic conditions almost identical with
those now existing, but slightly warmer — a difference doubtless
owing to the fact that Britain was then united with the
Continent.

THE FUNCTIONS OF LATEX.— In a very large
number of flowering plants, there are special sacs and tubes
containing the juice called latex, which is conmionly milk-like
in appearance {e.g. in dandelion, spurge, sow-thistle), but may
be colourless, or red. or orange in colour. Latex contains a
great variety of substances (e.g. proteins, starch, rubber,
alkaloids), and its uses to the plant have been much discussed.
Some writers state that latex is mainly, if not entirely,
composed of waste substances, which do not enter again into
the metabolism of the plant, though useful in guarding against
the attacks of animals, on account of the bitter and poisonous
substances they contain. Others contend that latex is largely
made up of reserve food materials, which are e\C3tually used
up in the nutrition of the plant.

The most recent contribution to the controversy is a paper
by Bernard (Annales dit jard. hot. dc Buitenzorg. 19101, in
which some interesting new facts are gi\-en. This writer
supports the view that latex functions largely as a depository
of reserve food materials. He finds that the fruits of various
latex-containing and rubber-yielding plants have abundant
thick latex when young, whereas the ripe fruits contain very
scanty and thin latex. This he regards as proof that the
substances present in latex are used up in the formation of the
fruits and seeds, after being converted into other food
materials. He also shows that when spurges are cultivated in
air deprived of carbon dioxide, so that they cannot manufacture
carbohydrate foods from external sources, the starch grains in
the latex are corroded and are apparently changed into sugar
for the nutrition of the plant.

.ACIDITY OF BOGS. — ,As is well known, the peat-moss
[Sphagnum I rarely grows on limestone soils. Some years ago,
it was shown by Paul that calcium carbonate is very injurious
to Sphagnum, even in small quantities. He grew various
species in water containing lime and found that the plants
soon perished. He found that not all salts of lime have an
equally injurious effect, and that alkaline salts of potassium
and sodium are as deleterious as those of lime. Various other
writers have found that peat-mosses give an acid reaction ;
hence it has been suggested that the injurious effects of lime

347

348

KNOWLEDGE.

September. 1911.

may be due to the neutralising of the acidity of the moss ;
that forms growing on high moors contain more acid than
those found on low heaths, and that the former are more
sensitive to lime; that on high moors there is less mineral
food available for the Sphagna in the substratum, and that
the amount of acidity and the sensitiveness to its neutralisation
decrease as the amount of available mineral food increases :
also that high moor Sphagna usually absorb more water than
those growing on low heaths.

Baumann and Gully iMitt. d. K. Bayr. Moorkiiltiirsiiafalt.
19101 have confirmed Paul's statement that lising Spliagniiiu
plants give the same free acid reaction as does peat derived
from the dead remains o{ Spliagiiiiiii. They also show that
living or dried Spliagniaii plants dissolve calcium phosphate
in the same way as peat. From numerous experiments, they
conclude that the acidity of peat and of Sphagnuiii is due to
the presence of colloidal substances of acid character in the
cell-walls.

Czapek showed, some years ago. that Spluiginiiii con-
tains various interesting chemical substances. ()ne of
these, " sphagnol." is injurious to Bacteria and thus acts as an
antiseptic, preserving the dead Spliaginiiii tissue from
destruction and helping in the formation of peat. The walls
of the clear water-holding cells of the leaves also yield on
treatment with alkah large quantities of jelly-like substance,
probably identical with Baumann's "Sphagnum colloids."

SENSITIVE STIGMAS.— As is well knowu, the flowers of
various species of Miinuliis (monkey-flower, musk) have a
stigma with two flat diverging lobes, which when irritated
shut together so that one stigmatic (inner) surface meets and
presses against the other. The inner surface is the sensitive
part, a touch on the outside of the lobes producing no eft'ect.
The closing movement is instantaneous ; after from five to
eight minutes the lobes begin to diverge again, and in ten to
fifteen minutes have regained the position of rest.

These movements, which occur in some other plants, e.g.
species of Torcnia and Martynia. were first described about
a century ago, but the only detailed account, until quite
recently, was that given in 1902 by Bruk, According to Bruk,
in Mini 111 us the lobes remain closed only it the stimulus has
been caused by placing on them specific pollen {i.e.. pollen
from the same flower or from a flower of the same species),
and soon open and remain open if foreign pollen (i.e. pollen
from a different species of plant) is used. He also stated that
in Torcnia fournicri the lobes will open again and remain
open if pollen from the two shorter stamens of the same
flower has been placed on them ; this point is referred to
below.

Oliver, in 1887, showed that the stimulus is transmitted
from one lobe to the other ; if one lobe is prevented from
moving leg. by cementing it to the corolla), a touch on its
inner face still provokes movement in the other lobe. He
also showed that the transmission takes place through the
ground tissue of the lobes, probably by means of intercellular
protoplasmic connexions, since transmission occurs when the
vascular bundle is cut through.

Lutz has made a thorough investigation of irritable stigmas
iZeitschrift fiir Botanik, 1911). The ground tissue of each
stigma lobe is sharply divided into two zones, the inner zone
foruiing the conducting tissue (down which the pollen tubes
pass) and the outer consisting of compact parenchyma; the
epidermis of the outer side is strongly cutinised and has no
papillae, that of the inner side has very thin cuticle and is
produced into long hairs which receive the stimulus of contact.
The movement of the lobes is brought about by a sudden
lowering of the osmotic pressure, and diminution in volume of
the whole ground tissue. The diminution in volume is not
uniform, but very different on opposite faces of the stigm.a
lobes, being in fact about twice as great on the inner face as
on the outer face. By artificially withdrawing water by
osmosis there can be produced a closing together of the lobes
similar to that resulting from stimulation.

Lutz carefully investigated the results of pollinating the
stigma of Mimuhis cardinalis. and so on, with pollen of the
same species and also with foreign pollen. He tried the effect
of placing pollen in different quantities on the inner surface
of the stigma lobes — on one small area, on about half of the
inner surface, on the entire inner surface. If little pollen is
used, whether of the same species or not, the lobes at once close,
then open again in about ten minutes. With more pollen,
enough to cover about half the inner face of the stigma lobe,
the lobes open again after about ten minutes ; but if the pollen
used is of the same species, a second closing movement begins
after from two to three hours and lasts for about twenty
minutes. If, however, the pollen is carefully placed on the
stigma to avoid mechanical shock, the second closing movement
occurs as usual after between two and three hours, although
the first (contact irritability) movement is not made. When a
large amount of pollen is used, the whole inner face of the
stigma being covered, the first instantaneous movement occurs
as usual, owing to the mechanical shock stimulus in applying
the pollen, but the lobes remain closed, never diverging again.
If the stigma is loaded with foreign pollen, it closes at once
as usual, and remains closed for two or three hours, but then
opens again.

In these interesting experiments with small, medium, and
large quantities of pollen, Lutz worked chiefly with Miinulus
cardinalis. and used in each case (1) pollen from long
stamens of same species, (2) pollen from short stamens of
same species, and (3) pollen from various foreign species —
Snapdragon. Plantain, and others. His results show that the
permanent closure or the reopening of the stigma lobes is
determined in the first instance by the quantity of the pollen
applied — a large quantity causes permanent closure, a smaller
quantity does not : and. secondly, by the origin of the pollen
used — a full load of pollen of the same species results in
prolonged closure, foreign pollen in closure for a few hours at
most. In opposition to Bruk's results, Lutz finds that in
Torcnia the anthers of the short stamens dehisce later than
those of the long stamens ; that pollen from undehisced
anthers is not capable of germinating ; and that when such
pollen is placed on the stigma, the latter opens in ten to fifteen
minutes after the usual closure.

Lutz proceeds to analyse the two closing movements which
result on the placing of suitable pollen on the stigma. The
instantaneous first movement is purely the result of the
mechanical stimulus. Bruk explained the permanent closing
of a pollinated stigma as being due in part to the pollen grains
abstracting water from the stigma tissue, and thus preventing
this tissue from returning to its original state of turgescence.
This explanation is supported by the observation of Lutz that
the stigma only remains closed when a large amount of pollen
has been placed on it. Lutz also noted that sometimes, even
with a full load of pollen, the stigma lobes after from one to
three hours opened again, doubtless recovering turgescence by
being supplied with water from the ovary and style — but this
re-opening would not. of course, interfere with fertilisation,
since the pollen had had ample time to germinate and send the
pollen-tubes into the conducting tissue.

Lutz found that not only specific and foreign pollen, but
also such substances as dry sand and powdered starch could
cause prolonged closure of the stigma lobes. On the other
hand, wet pollen caused only temporary closure (for ten to
fifteen minutest ; only dry pollen could produce prolonged
closure. The permanent closure, resulting simply from the
prevention of the automatic re-opening movement, is due to
( 1 ) the absorption of water by the pollen grains and their
germinating tubes, and (2) the chemical effects of the growing
pollen-tubes on the conducting tissue of the stigma lobes. If
either of these conditions be absent, the stigma lobes open
again after a shorter or longer time. Both conditions are
fulfilled by the germination on the stigma of the pollen of the
same species. This portion of Lutz's results may be
summarised by stating that the stigma remains closed only if
the pollen grains and the germinating pollen-tubes can, by
abstraction of water, prevent the return of the original osmotic
pressure in the stigmatic tissue, and the consequent reversal

Septembhr, 1911.

KNOWLEDGE.

349

of the primary closing movement, until a sufficient number of
pollen-tubes have penetrated the conducting tissue and so
disorganised it that re-opening of the lobes is made impossible.

The next question is, how do the entering pollen-tubes cause
this remarkable disorganisation of the stigmatic tissue ? The
entering tubes will resorb the very thin cuticle between the
stigmatic papillae, and they will, after some time, absorb
sufficient water to prevent a return to the original turgescence
in the stigmatic tissue, but the disorganisation of the stigma is
not entirely explained in this way. Evidently some chemical
substance or substances contained in the pollen grains and
tubes must diffuse into the conducting tissue, and there cause
disorganisation of the cells. Lutz tried the effect of watery
extracts of the pollen-grains. On placing a drop of this extract
on the stigma, the latter closed as the result of the mechanical
stimulus, and remained closed, also showing, after a few
minutes, a yellow discoloration, while the microscope showed
exactly the same kind of disorganisation of the conducting
tissue as is caused by the pollen tubes. The extract did not
act as a chemical closing stimulus on the stigma, however.
On putting a stigma into the extract it began to close gradually
after a few seconds, whether the stigma were irritable or not ;
this closing occurred in insensitive stigmas — old stigmas, and
stigmas made insensible by treatment with ether, for instance.
That is, the closing movement was due to chemical action
of the extract, but not to a chemical stiiinihts; the extract
injured the stigma cells but did not act as a stimulus to move-
ment. Iieyond ascertaining that the active substances
extracted from the pollen were not destroyed by heating to
100°C., Lutz made no attempt to isolate and identify them,
because exactly the same result was brought about by extract
of pollen of all kinds of other plants, and by solutions of various
organic and inorganic substances.

Clearly, then, the permanent closure of the stigma lobes in
Miiniiliis and so on, is brought about by abundant pollination
with pollen of the same species, while with foreign pollen (the
tubes of which either do not penetrate the stigma or only do
so occasionally and imperfectly) the stigmas open again after
a time. When killed pollen-grains of the same species are
applied to the stigma, the latter opens again in an hour or so ;
the dead pollen can absorb water from the stigma tissue, and
of course it still contains the chemical substances which
injure the stigma tissue, but it cannot produce pollen-tubes
which are required to conduct the chemical agent to the con-
ducting tissue.

Of what advantage to the plant are the movements of the
stigma-lobes ? t5ruk's answer was that the closing up of the
stigma-lobes is a protection against the germination of foreign
pollen. Lutz finds, however, that the pollen of some foreign
plants germinates almost as well on the stigmas of Miiindiis
and so on, as the plant's own pollen, though the foreign grains
do not seem able to send their tubes into the conducting tissue.
Hence it is not the irritability of the stigma that prevents the
growth of foreign pollen, but rather the specific chemical
characters of the pollen-grains, pollen-tubes, and conducting
tissue. Gartner suggested that the irritability of the stigmas
was necessary for the proper fertilisation of the ovules in the
ovary, but Lutz shows that fertilisation occurs even when the
stigma has become insensitive by age or rendered so artificially.
Of course, the germination of the pollen is favoured by the
closing process, which shuts the pollen grains into a moist
chamber, and Lutz concludes that this is the sole advantage
of the closing movement. When pollen is placed on the
stigma carefully, so that no movement results and the lobes
remain open, the grains germinate much more slowly than in
the normal case where the lobes become closed. Lutz watched
insects at work pollinating the flowers of Minnihts, Torcnia
sp., and others, and found that only very rarely did they place
sufficient pollen upon the stigma to make it close permanently
at once.

RECENT WORK ON E X P E R I M E N 1 A L
MORPHOLOGY.— In 190S, Goebel gave an account of the
interesting results already gained by experimental researches
on alterations in structure induced by the action of external

stimuli, or environment, and on the regeneration processes
that occur when parts are injured or removed. In this
work (" Einleitung in die experimentelle Morphologic der
Pflanzen"), Goebel emphasised the necessity of studying a
plant throughout its development as a condition for the under-
standing of its structure, pointing out examples that show
great diversity between the corresponding parts of the young
and the adult plant, and tracing these differences to causes
whose action could be tested by experiment. Such experi-
ments show that the action of the environment depends largely
upon the period of growth during which it has acted, and that
the characters of the earliest period may be retained in the
normally later stages, or may be reproduced in these stages by
the influence of an environment suitable to the earlier period.
For instance, the common harebell (the "bluebell" of
Scotland) shows rapid changes in the forms of its lea\es as the
result of changes in environment, these changes resulting from
very different causes such as diminished light, lessened supply
of water, increase in salts dissolved in water, and so on.

Goebel made the generalisation that these external influences
act indirectly by altering the amount and kind of the food
formed by the plant and needed to allow of the normal course
of development, the external form being conditioned by the
vital activity of the plant and by the food supply to each part
of it. Goebel holds that the quality of the food supply
explains the nature of the parts formed. For instance, the
formation of stolons in the enchanter's nightshade {Circaca
li(tctiana) is attributable to the amount of organised food
relatively to the inorganic ash constituents supplied to the
growing-point of the stolon, being greater than that supplied
to the leafy shoot. Again, if potato tubers are kept at a
temperature not above 7°C., few roots or leafy shoots are
formed, but new tubers develop rapidly, though remaining
small; if the parent tuber is then cultivated at about 25°C.,
leafy shoots are freely formed, the younger tubers of the new
growth often being changed into leafy shoots.

Dostal [Flora, 1911) has made a large number of
experiments with Circaca and some other plants, and the
results obtained by cultivating isolated pieces of stem, each
piece with a single leaf and bud, are of great interest. He
finds that axillary buds thus treated develop into either stolons
(underground runners) or flowering shoots, or transitions
between these two kinds of shoot, according to the position of
the leaf and bud — whether taken from the base, apex, or
middle of the plant. On the other hand, if the leaf is
detached from the piece of stem, the bud always produces a
sterile leafy shoot, no matter from what region of the stem
it has been taken. Again, if, in experiments with a leaf and
bud portion, the leaf is excluded from the light, the buds
always grow into sterile leafy shoots. Dostal also finds that
the development of a sterile leafy shoot depends upon the
food supply ; to produce a flowering shoot the proportion of
organic to inorganic food must be greater than that required
for the formation of a stolon. On the same material (food
supply) conditions depend also the various characters of the
kinds of shoot produced — their geotropic reactions (whether
the shoot will grow upwards or horizontally when laid flat),
the lengths of the internodes ("joints") of the vegetative
stems and the inflorescences, the size and form and number
of the leaves, the number of flowers, and so on.

Dostal's paper is of value as a careful and detailed working
out of the experimental morphology of a single plant, on the
lines indicated by Klebs and by Goebel. From the work of
Klebs, we know that the normal course of development in
any plant is only a special type of many developmental
possibilities ; that this normal sequence and no other is
usually met with must be attributed to a normal sequence in
the external factors. From Goebel's work, we gain further
generalisations, some of which have already been mentioned.

In dealing with the production of buds in abnormal
situations on various plants, Goebel shows that this is closely
akin to regeneration, both being specially active at the
growing-points of axes (stem or root) and of leaves ; that
adult tissue in various places may, however, revert to the

350

KNOWLEDGE.

September, 1911.

embryonic state, these areas being along the veins ; and that
the impulse to development, apart from external stimuli, is
conditioned by the presence of the necessary constituents of
the food, brought about in leaves — when the leaf-stalk is cut —
by the retention of the leaf's products within itself.

The phenomena of regeneration in plants have been much
studied, and the results obtained by experimental researches,
in which the plant is injured or has various organs removed,
depend primarily for their interpretation on the fact that the
various parts are correlated and influence each other. That
is, we may assume that every organ arising from growing cells
may develop in a variety of ways, and the direction of develop-
ment which it takes depends upon its relations to other parts.
When a stem or root is amputated, as in making cuttings, the
new organ arising may be already present as a rudiment near
the wound, or it may be formed from the healing tissue
(callus). As a rule, leaves or parts of leaves cannot be
replaced, but this does happen in some plants : as, for instance,
in Cvclitiiieii pcrsicitin, where new leaf-blades arise on the
leaf-stalk when the blade of a young leaf has been cut off,
Goebel states that in this case there is no real renovation of
the leaf-blade, but simply a continued growth of the leaf-base,
which was previously inhibited owing to correlation.

A remarkable feature in regeneration is the polarity of the
organs and of the individual cells. If the tip of a shoot is
removed, the bud nearest the wound develops : if the tip of a
root is cut oft", the nearest lateral root takes its place. A cut
willow branch, bearing buds, will, if kept in moist air, produce
at its upper end shoots only, and at its lower end roots only,
whether it is placed right way up or inverted. The branch
has an inherent polarity of its own, which was for long
regarded as fixed ; but Klebs showed that if the cork is
removed from the upper end of a cut willow branch, and this
end placed in water, roots will then develop from this end — by
allowing enough water to enter, owing to the removal of the
cork, the internal polarity of the branch is upset.

Doposcheg-Uhlar {Flora, 19111 has investigated the
regeneration and polarity in various plants, and has obtained
some remarkable results. He finds that the new shoots which
arise from a very young fern-plant, still attached to the pro-
thallus. when the growing-point of the plant is removed, strongly
resemble the young fern produced from the fertilised egg ;
there arises first a " cotyledon " independent of the growing-
point of the shoot. In some cases, moreover, the shoots
arising from cut pieces of fern rhizome (underground stem)
showed a curious leaf-like structure which protected the
young growing-point, in much the same way as the cotyledon
of the young fern plant protects the stem apex in its early
stages of growth.

Many other interesting experiments are described by
Doposcheg-Uhlar, whose paper is a model of patient and
ingenious work directed towards the establishment of new-
facts, and the solution of the many problems arising from the
stimulus given by Goebel in his invaluable Einlcitung.

It is much to be hoped that Goebel's book will be translated
into English. The earlier work on experimental morphology,
regeneration, polarity, and allied topics is well summarised in
Jost's " Plant Physiology " (Oxford Press),

SPORE DISPERSAL IX SELAGINELLA, — Various
recent contributions to our knowledge of the genus SclagiiwHa
have been noted in these columns. This time we have
to note an interesting paper by a German worker, F. W.
Neger, who has descrilsed the shedding of the spores in
Sclaginella helvetica and S, spiniilosa, in a recent number
oi Flora (N.F., Band 3. 1911).

In 1901, Goebel {Flora, Hand S8) showed that in various
species of Sclaginella examined by him the megaspores are
shed spontaneously, owing to a curious mechanism in the
structure of the sporangium wall. The structure of the
microsporangium is much simpler, the dehiscence mechanism
being less highly developed, so that the microspores, despite
their much smaller size, are scattered less widely than the

large megaspores. He also showed that the cones or
" flowers " of Sclaginella are usually protogynous, that is,
the megaspores are shed before the microspores, though the
latter germinate much more rapidly. These arrangements
tend to prevent self-fertilisation, or the fertilisation of the
eggs, produced on germination of the megaspores, by the
male gametes produced on germination of the microspores of
the same plant,

Neger has investigated the dorsiventral creeping species
S, heli'cfica, and the radially symmetrical erect species
i>', spinnlosa. On each cone there occur at the apex
microsporangia, at the middle both kinds of sporangia, and
at the base microsporangia again. The apical microsporangia
open first, then the two kinds of sporangia in the middle
region, and finally the basal microsporangia. That is. in
these two species the cones are at first protandrous, but after
the emptying of the whole of the megasporangia there are
always present undehisced microsporangia ; there are two
crops of microspores, some shed before the megaspores, and
the rest afterwards. Hence during the whole of the period
of shedding of megaspores there are ripe microspores ready
to germinate.

In S. helvetica, Neger finds that the cones as well as the
creeping vegetative shoots show dorsiventral symmetry, the
upper leaves being small and the lower ones large. This
species grows chiefly on vertical rock faces. In the middle
region of the cone, which grows upwards from the creeping
shoot, the megasporangia are chiefly found on the ventral side,
the microsporangia chiefly on the dorsal side. This arrange-
ment, which does not appear to have been previously noted,
is attributed by Neger to the better nourishment of the ventral
side owing to the larger leaves. Moreover, the ventral side is
turned towards the light, and its leaves are. therefore, in a more
favourable position for assimilation. Much more food is, of
course, required by the megaspores, the tissue of which has to
nourish the developing embryo, than by the minute microspores
which merely have to produce a few antherozoids. Since S,
helvetica grows in sheltered clefts and crannies, wind can only
play a small part in the dispersal of the spores. The dehiscence
mechanism of the niegasporangium is well developed, but this
mechanism would be of little use were the megasporangia on
the shaded dorsal side of the cone — the liberated megaspores
would then strike the vertical rock face close to the plant and
roll oft' or become entangled in the vegetative shoots. The
minute microspores, however, are easily carried away by the
lightest breeze, and the dehiscence mechanism in the micro-
sporangium wall is so feeble that the spores on being set free
hardly reach the substratum close by. In S. spinnlosa,
which forms horizontal patches with the shoots orthotropous
(erect), the cone shows no difterentiation into light and shade
sides ; the megasporangia are found all round the axis of the
cone, and the megaspores on being set free have a clear path
in all directions.

CHEMISTRY.

By C. .\iNS\voKTH Mitchell. B.A. (Oxox,), F,I.C,

BIOLOGICAL ACTION OF RADIUM.— Dr. Loewenthal
writing in ihe Zeif. aiigeicandf. Chein.. 1911, XXIV, 1130,
points out that the therapeutic action of certain mineral water
springs must be attributed, partially at all events, to their con-
taining a considerable proportion of radium. It is well known
that radium emanation has a pronounced stimulative effect
upon the enzymes (pepsin, trypsin, diastase) present in the
body, and the beneficial eftects of these springs are probably
due to this cause. Young plants and mould-fungi are also
favourably influenced by the action of a small quantity of
radium emanation, but they are injured by larger amounts.
The action of the i-adium emanation has also a marked effect
upon the white corpuscles of the blood, and it has been
proved by Gudzent that the same body increases the solubility
of sodium urate. This effect, however, is attributed to the
action of the product of decomposition of the emanation
termed " radium D." On this fact has been based a method

Septembkr. 1911.

KNOWLEDGE.

351

of treating gout by the application of radium emanation, and
it is claimed that the treatment has given good results.

RADIUM IN URANIUM ORES.— An estimation of the
amount of radium present in various uranium ores has been
made by Messrs. Marckwald and Russell iCIieni. News, 1911.
C I II . 2 77 ) . who have taken the ionising power as a measure of the
radium. Comparing the ratio of the radium to uranium
with that of Joachimsthal pitchblende (taUen as 1001. they
have obtained a value of 98-1 for thorianite, and 101.5 for
African pitchblende, but for autunite values ranging from
20-7 to 68 • 0, although the ratio of ionium to uranium was
much more uniform in this mineral. Since the life of ionium
is not less than thirty thousand years, the conclusion is drawn
that autunite must be at least one hundred thousand years
old. and that, therefore, the relatively low values for the
radium ratio are not due to the radium being of recent
formation. It seems more probable that the physical structure
of autunite is responsible for the difference, and that owing to
its possessing a much more spongy texture than pitchblende and
thorianite. the radium and lead have been partially extracted
by water from the mineral. This view is supported by the
fact that there is only a slight occlusion of helium in autunite,
and by analogous results obtained in the examination of the
mineral rutherfordite.

PROPERTIES OF METALLIC TITANIUM.— It is not
an easy matter to obtain the element titanium in a pure
condition, as is shown by the account given by Messrs.
Hunter and Jones {Rensselaer Polyt. Inst., No. 1, February
nth. 19111. of their attempts to prepare it. The products
obtained by reducing sodium, potassium, and barium titani-
tluorides with potassium in no instance contained more than
73-2 per cent, of titanium, while reduction of titanium oxide
by means of carbon invariably yielded products containing
upwards of five per cent, of carbon. Finally pure titanium
was prepared by heating together in a closed bomb a mixture
of titanium tetrachloride and metallic sodium, with the
greatest precaution to exclude all air. The reduction took
place almost instantaneously at a dull red heat, and products,
which on analysis showed from 99-9 to 100 per cent, of
titanium, were obtained.

As thus prepared titanium was a hard brittle metal
resembling polished steel in appearance. It melted between
ISOQ- and 1850' C, and had a specific gravity of 4-50. It
could readily be forged.

CHEMICALLY ACTIVE NITROGEN.— Pure nitrogen
that has been subjected to an electric discharge from a Leyden
jar undergoes a remarkable change, an account of which is
given by the Hon. R. J. Strutt. in a recent issue of the
Proceedings of the Royal Society (1911, LXXXV, 2191. The
gas after being removed from the region of the discharge
continues to glow during the process of returning to its
normal state. The glow is intensified by cold but diminished
by heat, and it is suggested that it may be due to the
dissociated atoms entering into combination again.

In this chemically active condition, nitrogen forms a
compound with ordinary yellow- phosphorus, while a large
amount of the phosphorus is transformed into the red
modification during the reaction. It also enters into combina-
tion with sodium and with mercury at relatively low
temperatures, the mercury product being an unstable explosive
body : while there is spectroscopic evidence that similar
compounds with other metals, such as cadmium and
magnesium, are produced.

When brought in contact with nitric oxide glowing nitrogen
reacts to form nitrogen peroxide, the reaction probably taking
place in accordance with the equation —

2 NO + N = NO.>+N.2
It also effects the decomposition of acetylene and of chlorine
and bromine derivatives of hydrocarbons, with the liberation
of the halogen and formation of cyanogen.

MINERAL CONSTITUENTS OF A DUSTY ATMOS-
PHERE.— A spectroscopic method of determining the nature of

the dust in the atmosphere has been devised by Professor
Hartley {Proceedings of the Royal Society, 1911, LXXXV,
A, 2711. A series of photographs of spark spectra was taken
upon one plate, and compared with a similar series taken in
an atmosphere of hydrogen, the differences showing which of
the lines were due to impurities in the metal electrodes and
which to the dust in the atmosphere.

It was found that the calcium and copper lines were intensi-
fied as the proportion of dust in the air increased, w-ith the
continuance of dry weather. With regard to the source of the
copper it is pomted out that this element is present in coal-
ash, and in the dust from the flues of chemical and gas
works, and that it is also introduced into the atmosphere by
the flashes of overhead cables : while the amount of calcium
is increased by tram and motor car traffic. In fact the
possibility of the copper or calcium in the atmosphere acting
as reagents, must be taken into account in all cases of
apparently spontaneous changes such as might have been
set up by traces of basic substances. They may also pro-
duce alterations in solutions that would not be affected by
exposure to a pure atmosphere.

GEOLOGY.

By G. W. Tyrrell. A.R.C.Sc. F.G.S.

NEW THEORIES OF \ULCANISM. — R. A. Daly
iProc. Ainer. Acad, of Arts and Sciences. Vol. XLVII.
No. 3, 1911, pp. 45-122) bases a paper on "The Nature of
\'olcanic Action" on his well-known theory of abyssal
iniection. He believes th.at the world-wide granitic terrane
underlying the interrupted sedimentary shell is itself underlain
by a shell of eruptible basalt, which is the source and " heat-
bringer " of all igneous action. He points to the fact that all
the great lava-floods of the world are of basalt, and have
welled out from great fissures which are supposed to have
tapped this basaltic substratum, although it is not supposed
that simple openings extend to this depth.

Other igneous rocks are believed to be due to the absorption
of the overlying acid shell, as abyssal injections of basalt,
caused by crustal deformation, work their way upwards by a
method known as " sloping." This involves the constant
wedging away of blocks from the roof of the resulting
batholith. and their solution in depth. The resulting mixed
magmas are called " sj-ntectics," and with or without
subsequent differentiation, are held to give rise to the known
variety of igneous rocks.

Daly holds that vulcanism is a subsidiary effect of abyssal
intrusion. He distinguishes three phases of volcanic action —
fissure eruptions, in which lava rises with great rapidity through
relatively thin cracks in the crust : eruptions through local
foundering of the roof of a batholithic intrusion ; and central
eruptions of the common cone and crater type. Fissure
eruptions are well known, and beside the recent Iceland
examples, there are numerous others belonging to past ages.
The Yellowstone Park rhyolite is beHe\ed to be an example of
the second type of volcanic action. This huge mass of lava,
cut by canyons to a depth of six hundred meters without
revealing its base, lacking horizontal division-planes indicating
successive flows, is without parallel amongst lava-flows. Daly
believes that it passes gradually downwards into a batholithic
mass of granite, and is due to the foundering of part of the
roof of this batholith, whereby the molten rock was solidified
under surface conditions.

Central eruptions are supposed to originate in a cupola-like
extension of the roof of a batholithic intrusion, where " stoping "
action would be intensified by a concentration of the hot
volatile magmatic fluids. On reaching the surface the
" cupola " would originate a volcanic focus, and a cone
would be formed. -At this stage the problem of the continu-
ance of the volcano becomes the problem of the continuance
of heat within the funnel.

352

KNOWLEDGE.

September, 1911.

There are five conceivable methods whereby heat may be
transferred from the magma to the vent : —

i. Explosive removal of material from the upper part of
the vent, followed by uprise of magma.

ii. Simple outflow of magma at the crater-lip.

iii. Thermal convection in the la\a cohimn.

iv. ■■ Two-phase convection."

\'. The uprise of super-heated juvenile gas through the
lava column.

.\t Kilauea, on the observation of which this theory is partlv
based, the first and second methods are inoperative ; the third
is known to be inefficient in heat-transfer ; but the fourth, a
process conceived to be due to the uprise of comparatively-
light, hot, gas-permeated magma in the lava-column, and its
return along the margins of the vent as comparatively heavy,
cooled, gas-free magma. — may bring a considerable quantitv
of heat to the surface. This process is believed to be the
cause of the lava-currents in the crater of Kilauea. The fifth
method may be eflicient as a heat-bringer at some vents, but
not at Kilauea.

A largely overlooked source of heat, according to Daly, is
that set free by chemical reaction between the constituents of
the hot and active magmatic fluids. Many striking figures are
given illustrating the great amount of heat evolved by the
reactions between the common elements of these fluids.

The process outlined above is known as the " gas-flu.\ing
hypothesis," and is considered analogous to that of a gas-
blowpipe.

Some explosive types, such as the Ries cauldron and
Bandaisan, are considered due to the contact of hot magmatic
material with vadose waters circulating within the rocks. The
explosions here are non-volcanic : but there may be all grada-
tions between this type, and those, such as the Hawaian
volcanos, characterised by quiet magmatic extrusion without
explosion. In ordinary volcanoes, there are great variations
in the proportions of magmatic and vadose fluids involved,
and consequently great variety in modes of eruption.

With regard to the now much-discussed r61e of steam in
volcanic action, Daly says : " Though the rise of hot magma
into rocks charged with vadose or connate water does often
cause explosion, the steam pressure produced by such vola-
tilised water can no more be regarded as the cause of vulcanism
than is the boiling of a kettle the cause of the heat in the
stove."

.4. BRUX. — Whilst Daly emphasises the adventitious nature
of the intervention of water in volcanic action, it is to Brun.
of Geneva, that we are indebted for what appears to be the
overthrow of the old axiom that paroxysmal eruption is due to
the explosive violence of steam. In the Geological Magazine
for June and July, Mr. E. B. Bailey, of the Geological Survey,
gives an illuminating review of the new book, " Recherches sur
r Exhalaison Volcanique " by this original and courageous
worker. One of the most valuable features of Brun's work is
the mass of new and exact experimental data he has accumu-
lated in respect to vulcanicity. Not only has he measured the
temperature constants of many minerals found in lavas, but
new work has been done in the methods of collection, extrac-
tion, and analysis of the various volcanic gases, both in the
field and in the laboratory. Experimental work on the
behaviour of rocks during heating has resulted in their classifi-
cation as " active " or " dead." Active rocks, typified by
recent lavas, expand and liberate gas at such a rate when
heated that the molten material fumes over the edge of the
crucible, like a miniature lava flow. Active acid rocks are
more violent than basic and give rise to veritable explosions.
Dead rocks, among which are schist, granite and gabbro, give
off gas during heating, but at a higher temperature melt quietly
without much expansion or violence. The temperature at
which gas is emitted in active rocks so rapidly as to cause
sudden expansion and explosion is called the " explosion
temperature." The maximum temperature possible at a
volcano is fi.xed by the explosion temperature of its magma.

The principal gases liberated at tne explosion temperature
are chlorine, hydrochloric acid, and oxides of carbon ; the
solids evoKed are chlorides of the alkali metals and
ammonium ; sulphur occurs but is always in small quantity.
Such water as is contained in ttie rock is always given ofl'
before the explosion temperature is reached. These con-
stituents, with the exception of carbon monoxide, are the
same as those actually emitted at volcanoes.

Brun's main thesis is that paroxysmal eruptions are an-
hydrous, and that the aqueous character of fumaroles is due
to the contact of volcanic heat with superficial waters. This
view is supported by many striking observations. It is shown,
for example, that near the crater of Vesuvius, the ashes fall
quite dry. but are extremely hygroscopic, owing to the presence
of chlorides of iron and magnesium. Morever. the ash which
falls is white ; whereas if it had been exposed to the action of
water vapour at a high temperature, it would redden immedi-
ately, owing to its content of ferrous chloride. In the crater
itself, such deliquescing salts as Fe-j CI,;, Fe Clj, Mg CU and
A\, CI,-., may be collected dry and undecomposed, whilst hot
water-vapour would immediately reduce them to oxides.

Further evidence is adduced from the study of the white
clouds which hang over volcanoes. These are generally-
regarded as water-vapour ; but Brun shows that they are
persistent, and insoluble in the atmosphere as they drift away
from the volcanic focus, and are therefore composed of solid
particles. .At Kilauea. Brun took a series of dew point read-
ings in the great white cloud as it drifted across the crater-lip.
His results show in every case a lower dewpoint for the air
within than for the air outside the cloud. The lowered dew-
point is believed to be caused by the dilution of the air with
anhydrous gases carrying hygroscopic solids in suspension.
On the contrary, a markedly elevated dewpoint was obtained
at the peripheral fumaroles, as was, indeed, to be expected.

It seems, therefore, that Brun has, at least, established the
anhydricity of volcanic exhalations ; and gre.at probability
attaches to his view that water is not the agent to which
paroxysmal eruptions must be attributed.

METEOROLOGY.

By John A. Curtis. F.K.Met.Soc.

The weather of the week ended July 22nd. as summarised
in the Weekly Weather Reports of the Meteorological Office,
was very fine over the greater part of England, but slight rain
fell in the North and West and in Ireland. In Scotland there
was frequent rain, though it was seldom heavy. Thunder-
storms were reported during the middle of the week.

Temperature was again above the average, except in
Scotland, where it was either normal or very slightly below.
Very high maxima were recorded in the South and East of
England and in the Midlands, the highest being 96° at
Greenwich, on the 22nd, with 94" at Margate and 93° at
Raunds. In Ireland the highest reading reported was 79°,
while in Scotland North and West the temperature did not
rise above 71°. .-At individual stations in Scotland and Ireland
the maximum did not reach 70°, and at Balta Sound, Shetlands,
it was only 59°.

The minima were above 40" everywhere except in Scotland,
where, at Balmoral, the temperature in the screen fell to 32°,
and on the grass to 30'. In the English Channel the minimum
was 55".

Rainfall was below the average except in Scotland N. and
E. The defect was very great in places, and the drought began
to be severely felt. In England S.E. the week was rainless.

In Scotland, however, there was much rain, the total for the
week exceeding 2-0 inches atGlencarron and Fort \\'illiam.

Bright sunshine varied a good deal. In most parts of
England it was again above the average, but in Ireland,
Scotland and the Northern parts of England it was in defect.
In Ireland N. the average dailv duration was less than three

September, 1911.

KNOWLEDGE.

353

hours, while in England S.E. it was over eleven hours. The
percentage of possible duration varied from eighteen per cent.
in Ireland N. to seventy per cent, in England S.E. and in the
English Channel.

The temperature of the sea water was generall}' high, the
means varying from 5Z -5 at Lerwick to 65°- 9 at Margate.

The weather of the week ended July 29th, was more variable
than that of the preceding week. In Ireland it was unsettled,
with frequent rain. Many thunderstorms were reported, that
in London, on the 2Sth, being very severe. Temperature was
above the average in all parts, the excess exceeding 7" in
England E. and S.E. The maxima were again unusually high,
though not c|uite equal to those of the preceding week. The
highest readings were 93" on the 29th, at Bath, 92' at
Tnnbridgc Wells, and 9P at Fulbeck. Oxford, Raunds, Cardiff
and Clifton.

The minima for the week ranged from 37' at Balmoral to
57° at Scilly. On several nights the minima over a large part
of England were as high as 60\ On the grass the readings
did not. as a rule, fall below 40 , but at Burnley. Balmoral and
Crathes, readings of 34' were observed, and at Llangammarch
the exposed thermometer registered 29' or 3° of frost.

Rainfall was much less than the average in most parts of
England, but was more than usual in Scotland N. and \\".. in
Ireland and the English Channel. In Ireland S. the total was
two and .a-half times as much as usual.

During the thunderstorm in London on the 2Sth 1 • 1 inches
of rain fell in South Kensington in fifteen minutes. On the
next day 1-21 inches fell in Dublin in forty-five minutes, and
2-14 inches at Kilkenny in two and a-half hours.

Bright sunshine was again in excess in England, but was
deficient in Scotland and Ireland N., and just normal in
Ireland S. The sunniest stations were Weymouth with 83-5
hours (77%) and Salcombe 82-6 hours (77%). On the other
hand, at Fort Augustus only 11-9 hours (10%) were recorded,
and at Nairn only 14 hours (12%).

The mean temperature of the sea water round our coasts
varied from 52' -7 at Lerwick to 67' -6 at Eastbourne.

The week ended August 5th was unsettled, but the rainfall
over England E. and S.E. was again very slight. Thunder-
storms were experienced in most parts, and in some cases
these were accompanied with very heavy showers. Tempera-
ture was above the normal in all districts, by as much as 7°- 1
in England E. The highest maxima reported were 88° at
Cambridge on the 30th July, with 87° at Cromer and Hillington,
and 86° at Greenwich. In Jersey the highest reading was 76°.
The lowest readings varied much. At West Linton the
minimum was 42°, and readings below 50° were reported at
many stations. The lowest reading reported at Jersey was 57°.
No frost on the grass was reported during the week.

Rainfall was largely in excess in most of the western districts,
but over the rest of the country it was still in defect, and in
England S.E. it was less than one-fourth the usual amount.

Sunshine was in excess in all Districts except the English
Channel where it was slightly in defect. The district values
ranged from 63 hours (59%) in England E., to 35 hours
(32%l in Ireland N. The sunniest stations were Felixstowe
72-8 hours I68%l and Clacton 71 ■ 7 hours (67%l. At West-
minster the total duration was 55-9 hours (52%l.

The temperature of the sea water varied from 53° at
Lerwick to 71° at Margate.

The week ended .August 12th. was very fine and dry. though
with slight rain in Ireland and Scotland, and some thunder-
storms. Temperature was remarkably high and in England
E. the district mean was as much as 9-2 above the average.
In most parts the hottest day was the 9th, when temperatures
higher than any previously recorded in the United Kingdom
were reported. The highest reading was 100° at Greenwich,
which is the highest reported since precise observations were
begun there in 1841. The previous highest was 97°1 in July,
1881. Other very high readings were 98° at Raunds, Epsom
and Canterbury, and 97° in London, and Hillington, Norfolk.

Dr. H. R. Mill, the head of the British Rainfall Organization,
writing in Syinons's Meteorological Magazine says that the
maximum temperature at Camden Square was 97° -1 at
2.15 p.m. on .August 9th, the previous highest, since the record
began in 1858, being 95°-2 in July, 1900. On the same day at
Mill Hill, 380 feet above sea level, while the maximum in the
Stevenson screen was 95° -8, Mrs. H. R. Mill noted the
reading of a black bulb thermometer in vacuo as 142° -4. On
July 22nd this year, however, with a screen reading of 90° -0,
the black bulb was as high as 146° -8.

The lowest readings ranged down to 41' at Wick and to
42° at Gordon Castle. In Jersey the minimum for the week
was 59°, and on several nights over a large part of England
the temperature did not fall below 60°. No ground frost was
reported, but at Crathes the exposed thermometer fell to 33°.

Rainfall was largely in defect in all districts, and over the
greatest part of England it was very slight indeed. At many
stations the week was rainless.

Sunshine exceeded the average in all districts, the values in
England S.E., being 79 hours (75%). The sunniest stations
were Felixstowe. 88-2 hours (84%1, Brighton, 86-9 hours (84%),
and Hastings, 86-2 hours (83%). The mean temperature of
the sea water ranged from 55°-0 at Lerwick to 68°-3 at
Margate.

An unmanned balloon sent up at Mungret College, Limerick,
on July 6th. reached a height of thirteen miles. The lowest
temperature met with on this ascent was —57° C, at about
seven and three-quarter miles above the ground.

MICROSCOPY.

By A. W. Shehpard, F.R.M.S.,

zaitli the assistance of the following microscopists : —

Arthur C. Bankield. .Arthur Earland, F.R.M.S.

The Rev. E. W. Bowei.l, II. A. Richard T. Lewis, F.R.M.S.

James Burton. Chas, F. Rousselet, F.R.M.S

Chari.es H. Caffvn. D. J. Scourfield, F.Z.S., F.R.M.S.

C. D. Soar, F.L.S,, F.R.M.S.

MICRO -FAUNA OF A SEWAGE FILTER BED.—
This short note is the result of isolated observations I have
made from time to time, over a number of years, as occasion or
necessity arose for paying a visit to the works where the
process of sewage purification is carried out. The large
variety of bacterial fauna present in such a nidus will not be
touched upon, but only that part of the life which can be
readily observed by the average microscopist. The bulk of
the organisms herein noted, can be examined in a cursory way
with a good pocket lens.

A sewage bed, as most of my readers are probably aware, is
a specially constructed area for dealing with liquid sewage.
The particular type to. which this note relates is circular in
plan, and is filled to a depth of about six feet, with a specially
prepared material or " media," as it is termed, which forms a
■' nidus " or breeding ground for the bacteria responsible
for the process of purification. The " media" is prepared
from what is known locally as " Blast Furnace Slag " broken
to varying degrees of fineness, ranging from a quarter of an
inch to two inches in gauge. The sewage is applied to the
surface of the bed by a travelling form of distributing
apparatus similar to an elongated water wheel, which has
a circumferential together with a rotary motion on its own
axis, and so sprinkles the sewage evenly and regularly over
the whole area of the bed.

On taking up into the hand a piece of the " media " one is
struck with the gelatinous covering, which forms as it were
a sort of blanket enveloping the whole piece under examination.
This covering consists largely of bacterial life which is outside
the scope of this note.

The first form of active life noticeable consists of a large
number of small black bodies which, on a closer inspection,
reveal themselves as a sort of " fly." They are very different

354

KNOWLEDGE.

September, 1911.

from the fly as the ordinary individual observes them, and if a
piece of " media " is taken in the hand and the " flies " shaken
off on to a piece of white paper, they will be seen to move
about by a series of sudden sharp jumps, sometimes covering
a considerable distance in comparison with their own length.
They belong to the Order CoUembola and are referred to by
microscopists in popular language as " Springtails." To give
the reader some idea of the immense number found on a bed
I have on many occasions observed an area of four to six feet
(superficial) covered to a depth of one quarter of an inch.
These insects are not confined solely to the surface of the
bed. On digging out the " niedia " they will
be found to a considerable depth, but in
much smaller numbers.

The next dwellers in this odorous habita-
tion are, strange to say, our very interesting
friends, the spiders. My friend. Mr. F. P.
Smith, some little time ago. identified a
collection for me as consisting of two species.
viz.. Porrhnmma niicroplitlialiiiii and
TiiicticKs simplex, the latter by no means
a common species. Both sexes of each were
taken. While on the subject of spiders it
may be interesting to mention that during
certain months of the year it is a common
spectacle to find in the early hours of the
morning the whole surface of the bed
covered with a network of webs. It is an
extremely pretty sight, and I have several
times endeavoured to take photographic
records, but without any satisfactory measure
of success. The spiders, like the " Springtails," appear to be
equally at home in the depths of the bed. In fact, they are
much more evenly distributed.

On the bottom of the outlet channels there is usually a layer
of finely divided mud, or "humus" as it is termed, and on
skimming this layer one can generally obtain the Desmid
Clostcrhiin ciisis, but not in very large numbers. .Amongst
the Protozoa there are specimens of Arcclla. Actinoplirys sol,
and Difflti^ia. Coming to the Infusorians there are found
Coleps, Stcntor and VorticcUa, the latter forms sometimes
being taken in large numbers. The slipper animalcule
Paramoccium, it is almost

needless to say, can always . — . — - — .
be found.

.•\mougst the Entomostraca
specimens of Cyclops are
plentiful, together with Daph-
iiia piilcx.

A few Rotifers are some-
times taken, and the same
remark applies to Voli^ox
glohafor and the freshwater
polype Hydra virUlis.

The variety of microscopic
life would probably be larger,
but owing to the method of
working, and the constantly
changing character of the
sewage, it is somewhat sur-
prising to find the variety
herein enumerated.

.A peculiarity which can perhaps be easily accounted for is that

whilst it is possible to keep specimens of the forms mentioned

in captivity for considerable periods of time, when the collection

has been taken from a freshwater pool, this is not the case with

those collected from this particular gathering ground. Vorti-

cella and the larval forms of Cyclops die very quickly unless

the collection is poured out into a shallow dish. In this way

I have kept the several forms of life in an active condition for

a considerable time. ,- ,, „

Geo. p. Deeley.

ANABAENA CIRCINALIS.— The water in one of the
ponds near Totteridge Common, visited by the Ouekett
Microscopical Club on their Saturday afternoon excursion late in
June, was of a decided green colour, almost like green pea soup.

Figure 1. Anabac/ia circiiujlis

The appearance was caused by the presence of many different
species of minute algae, most of them of an indefinite charac-
ter, such as would be classed with the Protococcaceae and
Palmellaceae,with some Scciiectcsiiins and zoospores of various
kinds. But the greatest effect was produced by a less doubtful
plant. ■ It was so plentiful that it was not necessary to con-
centrate the take with the net ; it could be obtained abundantly
for examination by merely dipping a bottle into the water. It
obviously belonged to the not very easily discriminated family
— the Nostocaceae — and was probablv Atiabacna circinalis
(Figure II. It consisted of free-swimming short filaments,
composed of roundish cells averaging about
4a' in diameter, with bluish-green coarsely
granular contents. The filaments were
twisted into helical coils of from two to
six turns, or occasionally even more, often
very symmetrically arranged. Most of the
coils had intercalated in them a rather
larger quite spherical cell with clear con-
tents— the heterocyst. Sometimes a spore
also was present : these are oval, granular
and larger than the ordinary cells, V'egeta-
ti\e cells undergoing division were not un-
common ; in this case they were larger than
usual and more or less constricted in the
middle, according to the stage the process
had reached. A singular feature was, that
the direction of the spiral in most cases
changed at the heterocyst ; this is shown in
the top and bottom examples in the figure.
When the filament was a short one, this gave
rise to a peculiar M-shaped form with turned up ends, as
shown in the extreme left hand example. This form was
very plentiful. Various species of Anahaciia are not at
all infrequent in the freshwater plankton but the present
variety is certainly not very common.

The specific determination of many of the lower algae is
very difficult with the text books at present accessible
to the ordinary microscopist, and everyone desiring to
study this interesting class must be anxiously awaiting
the appearance of Professor West's anticipated work,
with fuller details than were possible in his " British

Freshwater .Algae " published

in 1904.

J. B.

Figure 2. Hvdrnnis foctidiis \'ill.

H VDkik-US FOETIDUS
iVILL). — In the August num-
ber of " Knowledge " (page
320), a note was published
on the above, but the subject
proved too difficult for photo-
graphy ; we are, however, now
able to reproduce drawings of
the plant (Figure 2). The lower
drawing represents a small,
sparsely-branched plant ; us-
ually the branches are much
closer together and of a more
filamentous character. Above,
on the left, such a branch is
figured, and shows the small
coloured bodies embedded
in the gelatinous matrix. On the right is a small piece
of a thicker stem, showing the same bodies and their arrange-
ment in that part, where they become more elongated and less
frequent than in the thinner portions of the plant. The magni-
fications are approximately X 25, X 70, and X ISO respectively.

J.B.

ENTAMOEBA COLL— In the Annals of Tropical
Medicine and Parasitology, Vol. V., page 111, appears a
paper by Dr. H. B. Fantham, " On the amoebae parasitic in
the human intestine, with remarks on the life-cycle of
Entamoeba coli in cultures." The3amoebae begin to encyst
on the culture-media which the author has been using, in
about four days, the cyst wall of each being formed by
differentiation at the periphery of the now rounded amoeba.

September, 1911

KNOWLEDGE.

355

The cyst at first contains a centrally-placed nucleus, with a
karyosome. Inside some of the cysts division occurs, and
eight daughter forms .are produced.

The author tried the effect on Entamoeba colt of
'■ auxetics," substances such as tyrosin and leucin, occurring
naturally in the human body and capable of inducing division
in living cells. The substances are best used in a jelly with
agar, sodiuni chloride and an alkali (sodium bicarbonate),
forming a slightly alkaline culture medium. When such a
medium containing about 0-2 per cent, of tyrosin is inoculated
with cysts of Etitaniocba coli, the period of the life-cycle is
shortened and the amoebae in the culture reproduce for
several generations. The author mentions a culture which
had gone through five generations. One interesting and novel
result on tyrosin-containing media is that a complete life-
cycle of Entamoeba coli is passed through in about three
days (at 20' to 25" C.l, when all the amoebae of a given
generation have encysted. Then a large number of the cysts
produce eight daughter forms inside them, and the amoebulae
come out of the cysts and start a new generation in the same
medium. The process of binary fission which also frequently
occurs in such media involves a primitive mitosis (or
promitosis! of the nucleus, caps of chromatin derived from
the karyosome being formed at the ends of the rudimentary
spindle.

The subject of this research, Entamoeba coli, is usually
considered to be non-pathogenic : it lives in the lumen of the
large intestine and on the contents thereof; it is incapable of
penetrating the mucosa. The size is slightly variable from
12 to 25 ," in diameter.

G. Plant Deelev.

ORNITHOLOCxY.

By Hugh Boyd Watt, M.B.O.U.

A NEW BRITISH BIRD — THE ALPINE RING-
OUZEL. — The occurrence of this form of the Ring-Ouzel
(Tiirdiis torqiiatiis alpestris) is recorded for the first time
in Great Britain by Mr. M. J. Nicoll, in British Bints (V,
August. 1911. pages 72-73), on the strength of an adult male
shot at Guestling, Sussex, on 23rd May, 1911. The illustration
given shows the form to be generally whiter in appearance
than the common Ring-Ouzel. The Alpine bird has a wide
range, extending in the breeding season throughout middle and
south Europe to the Balkans,

THE IRISH COAL-TITMOUSE— (P.4/^t'.S HIBER-
XICUS). — In the current number of The Ibis (9th Series
V, July, 1911, pages 54,S-552), Mr. W. R. Ogilvie-Grant gives
what may be taken to be a definite finding on this bird (see
''Knowledge" for March, 1911), He modifies his earlier
claim for its full specific rank, and, as the British Coal-Titmouse
also occurs in Ireland, and the two forms to some extent
intergrade, he now regards the Irish bird (P. hiberniciis) as a
sub-species only, though a very distinct one.

Mr. Ogilvie-Grant makes the suggestion that some characters
of the Irish bird indicate that its origin is much more ancient
than its British representative, and that it is a pre-glacial type
which has survived in the western and southern parts of
Ireland. He points out that the form most closely allied to
the Irish bird is, in many respects, another Coal-Titmouse
iPanis ledoucii Malh.,) peculiar to Algeria and that the
Lusitanian element in the fauna of Ireland is illustrated by
this. He remarks that the distribution of the Strawberry tree
(Arbutus unedo'i, which has a wide range in the Mediterranean
region and is found in the neighbourhood of Killarney as well
as in Algeria, is most interesting, as bearing on the question of
the Irish and .Algerian Titmice, \\'hat bearing the interest
exactly has on the case of the Irish Coal-Titmouse is not
stated,

GROUSE AND DISEASE. — " No disease" is the
prevailing report from grouse moors this season, and in

addition to the healthy state of the birds their numbers in
Scotland are believed to be greater than in any past year.
This exceptionally good season coincides with the publication
of the elaborate report of the Committee on Grouse Disease,
the result of some six years investigations, under the Chair-
manship of Lord Lovat, the general (juestions being treated
bv Mr. X. S. Leslie and Dr. E. A. Wilson and the scientific bv
Dr. A. E. Shipley.

According to the experts, who have gone into the whole
matter with a thoroughness that entitles them to utter the last
authoritative word on the subject, the one disease among grouse
that spreads havoc and desolation among the birds is caused
by what Lord Lovat — turning the expert's highly technical
nomenclature into the plainest possible language — terms an
over-infection of the Strongyle worm — a worm that is found in
practically every grouse on a moor ; that is to say (to quote
Lord Lovat), "that almost every bird (grouse) contains in its
body, under normal conditions, the immediate caiise of
" grouse disease," and is to a greater or less extent an agent
for the dissemination of that scourge." This means that the
Strongyle worm will be found to-da\- in practically e%'ery one
of the unusually numerous and healthy grouse on practically
every moor in Scotland. And the Strongyle worm has always
been there, but where and w^hen the grouse — so to speak — are
stronger than the worm there is no " disease." The " disease"
breaks out when and where the worm is stronger — so to speak
— than the bird, although of course the strength of the worm
has nothing to do with its name. It follows, therefore, that in
the present year, with grouse so healthy everywhere, the con-
ditions must have been such that the birds have been able
to keep their worms under proper check, and if that be so it is
e\ident that to those in any way skilled in moorcraft — with the
Committee's two sumptuous volumes in their hands, and by a
study of the conditions — there should now be little difficulty in
so managing grounds and grouse alike that the largest possible
stocks of the healthiest possible birds should be the result. —
The Glasgo-u' Herald. 12th August, 1911.

There is every likelihood that the sport will be so managed
during the present season that 1912 should prove as healthy a
grouse year as 1911 — if the w-eather also help as it has
undoubtedly done during this and last year. .According to
Lord Lovat, in his admirable chapter on moor management in
the Committee's final report, " the immediate objective of the
moor owner (who wants good stocks of healthy grouse) stands
out clearly — to keep the Strongyle infection at its lowest, to
keep the power of resistance of the stock at its highest, and at
the same time to maintain the greatest number of birds that
the moor is capable of supplying with suitable food." To
put it briefly and in practical language, his Lordship suras up
the whole matter in these further words — " Moor management
is the science of distributing the stock of birds over the moor
so that at no period of the year can any area be so infected by
the Strongyle worm as to make it a source of danger to the
least well-nourished bird on that area,"

MARKING BIRDS AND MIGRATION.— There are

some reasons for looking with dubiety on the v.arious bird-
marking schemes now in operation. Their partial and limited
scope, and the danger of making general deductions from the
meagre returns obtained, are fair points for consideration, and
also the destruction of bird-life which may be entailed in pro-
curing these returns, although such destruction is not approved
of by the inquirers. Those who share such apprehensions are
recommended to study Mr. A. Landsborough Thomson's recent
paper on "The Possibilities of Bird-Marking, with special
reference to the Aberdeen University Bird-Migration Inquiry"
(Proceedings Royal Physical Society, Edinburgh, XVTII,
3, 1911, pages 204-218), which gives, in admirable terms, a well-
considered and reasoned statement of the subject, .Apart
from general and historical and other results, of which a good
and valuable account is given, covering Great Britain, the
Continent and the U,S..A., the paper tells of the particular
investigation now in hand at Aberdeen, This has the advan-
tage of being a piece of research work organised under a
responsible body, viz,, the Natural History Department of the

356

KNOWLEDGE.

September, 1911.

Cniversity of Aberdeen. Properly controlled methods and
results should accordingly be assured, and, while Mr. Thomson
writes as an enthusiast, he does so judiciously, and does not
overlook the difficulties nor exaggerate the possibilities of
the subject.

For some of the .Aberdeen returns already reported see
" KNOWLEDGE" for May. 1911 (page 198).

We wonder wh\- so few or no returns seem to be forthcoming
from one class of birds, viz.. the game-birds which, owing to
the numbers meeting death from the hands of man, would
seem to be liliely to yield a larger percentage of returns to
the numbers marked than any other class of birds. We
do not overlook the returns regarding Woodcock, but refer
more particularly to Grouse. Partridge and Pheasant,

ACCLIM.-^Tl/INCx PAKADISE-BIRDS.— As stated in
"Knovvlehge" for June. 1911 (page 2371. Sir William
Ingram has bought the uninhabited island of Little Tobago,
West Indies, and is attempting to acclimatize the Greater
Bird of Paradise [Paradisea apoda) there. In the
Avictiltiiral Magazine (II, 5, 1911) he reports that he has
turned out forty-eight birds and that two others were to be
sent later. The island consists of four hundred acres of
forest jungle and the birds have spread over the whole area.
They eat fruit, insects and young birds and eggs of other
species. Four are known to have died, and none ha\e yet
mated.

PHOTOGRAPHY.

By C. E. Kenneth Mees, D.Sc.

L.\TITUDE OF EXPOSURE IN LANDSCAPE
PHOTOGR.'\PHY. — It is well-known th.it in landscape
photography there is very considerable latitude in the
exposure which may be given, a range which is sometimes
ascribed to the latitude of gradation which the photographic
dry plate is capable of accurately rendering. Experimental
investigation, however, shows that the range of light intensities
which can be reproduced accurately by an ordinary photo-
graphic dry plate is only about one to twelve or one to
sixteen, that is to say, this is the range of intensities which
are included in the straight line portion of the characteristic
curve of a plate, or is the range of intensities comprised
within the period ol correct exposure of a plate.

o

6-4. fia ^6 -ii^

Intensities.

Figure 1.

The figure shows the " characteristic curve " of a plate,
that is, the relation between the light intensity acting on the

plate during exposure and the amount of metallic silver
reduced by development.

It will be seen that this curve may be divided into three
portions: — A portion. .AB. where the reducible silver increases
more rapidly than the geometrical increase of the intensities, a
portion, BC. where the increase rates are proportional, and a
portion, CD, where the increase of silver with increasing
exposure diminishes.

These three portions are known :

.4B, as the period of under-exposure,

BC, the period of correct exposure, and

CD, tiie period of o\'cr-exposure.

For the curve shown the range of intensities in the period
iif under-exposure is about one to eight, the range in the
period of correct exposure eight to one hundred and twenty-
eight, or one to sixteen.

Since one to fifteen is about an average range of intensities
for an ordinary landscape subject, it is obvious that, strictly
speaking, a plate has no latitude at all, that is, any deviation
from one fixed exposure, which we may call correct exposure,
will cause one end or other of the intensity scale to fall out of
the period of correct exposure of the plate, so that, except for
one particular exposure, an a\'erage landscape must have some
of its intensity scale rendered either within the under- or
over-exposed periods of the plate curve.

In practice a plate is not considered under exposed provided
that any deposit at all is obtained in the deepest shadows,
which implies that instead of the effective range of light
intensities starting at the beginning of the period of correct
exposure, in practical photography the range of light intensities
starts at the beginning of the period of under-exposure, and
the rule that the exposure should be given for the shadows —
the safest of all rules in landscape photography — means that
the range of intensities on the resulting negative will be repre-
sented in both the under-exposure and correct exposure
periods of the plate curve. An increase of four times this
exposure will merely serve to shift the shadow exposure from
the beginning of the under-exposure region to the beginning
of the correct exposure region of the curve, and we may there-
fore expect an apparent latitude of at least one to four in
the direction of over-exposure. If we again increase the
exposure, we may shift the upper part of the scale of gradation
into the over-exposed portion of the curve, but for some
considerable distance the effect will not be appreciable to the
eye, and it may, therefore, be taken as a practical working rule
that if a given exposure is the least which can be given to get
the deepest shadow detail represented by the smallest possible
deposit on the plate, eight times that exposure will still give a
perfectly satisfactory negative.

It is a matter of considerable interest to measure the
amount of light reflected from the shadows of landscapes by
means of such an instrument as the " Lumeter " referred to in
the May number of " Knowledge." Experiments showed
that in order to get a negative in which shadow detail was
rendered by a minimum deposit on a plate of one hundred
Watkins, it was necessary to give one-tenth of a second
exposure at FS, if the light reflected from the shadows of the
subject was of one hundred foot-candles intensity, and measure-
ment of a number of subjects showed that in bright sunlight
in the summer, the illumination in the shadows varied from
about three hundred to fifty foot-candles, according to the
depth of the shadow. The deduction drawn from such
measurements appears to lead to a complete confirmation of
the rule made by most experienced photographers, namely,
that it is difficult, with a hand camera at any rate, to over-
expose landscape subjects, and that a general rule when
dealing with a landscape in which there is a considerable
degree of contrast, is to give as much exposure as possible.
It mav be said, indeed, that one-tenth of a second at F8 will

September, 1911.

KNOWLEDGE.

357

rarely be found too long for a landscape subject with a close
foreground.

When, however, there is no close foreground in the subject
and little deep shadow, the range of contrast becomes very
much less, it is quite possible for the intensity ratio between
the darl<est and lightest parts of an open landscape to be
only one to three, and in this case it is absolutely necessary
that care should be taken to keepontheside of under-ratherthan
over-exposure, because, whereas with contrasty subjects the
aim of the photographer must be to compress his scale in order
to get it within the scale of the printing paper, with flat subjects
having little range of contrast the object of the photographer
must be to increase the contrast in order to get an effect
pleasing to the eye. even though not necessarily a perfect
rendering of the original. One effect of this desirability of
increased exposure for increased contrast is found when such
unusual subjects as tropical or alpine landscapes are photo-
graphed. In the tropics, with vertical sun and the absence of
cloud, there is very little sky light to illuminate the shadows,
and the shadows are consequently extremely deep and show
much contrast with objects illuminated by the direct rays of
the sun. This increase of contrast compensates almost com-
pletely for the greater intensity of illumination, and it is
probable that a plate in the tropics should be given quite as
much exposure for the same type of subject as would be
required in England. Such photographs of the tropics as
have come before my notice seem to bear this out very fully ;
they are nearly all under-exposed, in spite of the great
intensity of illumination available. In the same %vay, the in-
tensity of the light in the high alps is largely counter-balanced
by the increased contrast due to the lack of sky illumination
in the shadows, so that skilled alpine photographers almost
always advise that plates in the high alps should be as fully
exposed as if the camera were being used in England.

The relation between contrast and exposure does not seem
at present to have been fully worked out ; but there is no
doubt in my mind that it is a subject which will well repay
investigation, and that a discussion of practical photography,
based on a number of experiments checked by direct measure-
ment of contrast and intensity, would be of very considerable
educational value for all classes of photographers.

PLATINOTVPE PRINTING. — Of all photographic
printing processes, the Platinotype process is recognised to be
that which gives results of the greatest beauty and the most
absolute permanencj'. It is also an extremely quick process,
requiring little time for manipulation, and, provided the
exposure is correct, producing results of unvarying excellence.
Unfortunately, however, it is not a printing-out process, and it
is necessary to judge the depth of the printing from the
appearance of the faint image produced by exposure to light,
a matter which, while it presents no difficulties to the
experienced worker who is continually doing it. is not so
easily undertaken by one who only prints in Platinotype at
rare intervals, and who is likely in the meantime to lose his
sense of the necessary printing depth.

The use of mercury vapour lamps, however, both for light-
ing purposes and, as quartz lamps, for experimental work in
scientific laboratories, puts within the reach of every possessor
of such a lamp an almost perfect method of making platinotype
prints. Mercury vapour lamps are almost always regulated
either by hand resistances controlled by an ammeter or by
iron wire ballast resistances enclosed in hydrogen, and
consequently the intensity of illumination is very uniform and
the prints can be exposed entirely by time. At twelve inches
distance from a single Cooper- Hewitt tube taking three and a
half amperes, the exposure for an ordinary negative will be
about ten minutes, and a number of negatives can, of course,
be placed side by side under the long tube at one time. A
quartz lamp taking the same current at one hundred and ten
volts would require about five minutes' exposure at twelve
inches. This suggestion may be found useful by those
workers who have a, mercury vapour lamp a\'ailable.

PHYSICS.

By .\I.FRED C. G. Egerton, B.Sc.

"SPHEROIDAL STATE." — When a little water is
allowed to drop on to a hot plate of metal heated to 300°C
about, it is well known that small spherical drops are formed
which run about on the surface of the metal ; these finally
either diminish in bulk owing to formation of steam or
collapse, produce a considerable quantity of steam and spread
out on the hot surface if the latter cools to a sufficiently low
temperature. The water is said to have gone into the
■■ spheroidal state." The phenomena are well demonstrated in
a lecture by means of a silver dish perforated with a hole in
the bottom. The dish is heated by a burner, which is
removed ; a drop or two of water shaken on to the dish con-
tinues to move rapidly about on it until the metal has cooled
sufficiently when the drop resumes its ordinary condition and
can fall out through the small hole in the bottom of the dish.
The phenomena can be shown very distinctly by an
experiment of Sir James Dewar"s. A drop of liquid air is
allowed to fall on to small flat bottomed dishes containing
such liquids as sulphuric acid, ethyl alcohol, or carbon
tetrachloride. In each case the drop of liquid air assumes
the spheroidal state and moves rapidly about on the surface
of the liquid : but in the case of the more volatile liquids, such
as ethyl alcohol and carbon tetrachloride, the drop is
surrounded by a cloud of the condensed vapours of these
li(|uids and. as it mo\es about, is followed by a cloudy tail.
The drop impinging on to the walls of the vessel shoots off
again as if possessed of perfect elasticity.

When the drop of water or liquid air first touches the hot
surface there is considerable production of vapour, which acts
as a cushion and prevents the liquid from coming into actual
contact with the hot surface. The liquid is then free to
assume the spherical drop form, which is due to the attraction
of the inner molecules upon the molecules residing upon the
outer skin of the liquid ; the drop then tends to become
spherical, so as to make the ratio of the surface to the volume
as small as possible. Imagine a little water to have been
allowed to fall on a hot plate ; there will be a sudden
production of steam, the water will disrupt into several distinct
drops which, since they are not actually touching the metallic
plate, will retain a spherical form, being buoyed up from the
plate by the cushion of steam. Since the under surface of the
liquid is heated most there will be more steam formed here,
and more molecules will leave the drop at the point nearest
the plate ; there will be then a continual disturbance of the
surface tension equilibrium along the surface of the drop,
tending to cause a rotation within the drop. The vapour pro-
duced will tend to shoot out from under one side more than
another, and so cause an initial movement in some particular
direction, and give a definite direction to the rotation of the
drop, which is maintained until some other disturbing influence
is met with.

The motion of a particle of potassium or sodium when
thrown on to water is very similar to that of a liquid dropped
on to a sufficiently hot surface. The potassium causes a pro-
duction of hydrogen and also a considerable quantity of heat ;
some of the water is vaporised and no doubt the action is
carried on between the potassium and a thin jacket of steam,
the hydrogen produced acting as the supporting jacket for the
pea of potassium.

The motion of the drop, its rotation, its collapse and the
curious palpitations it undergoes when rather too much is
added to form the true spheroidal state, are very prettily
illustrated by Sir James De war's experiment. The collapse of
the drop is no doubt due to the actual contact of the drop
with the hot surface, the surface tension equilibrium being then
completely upset, causing the drop to wet the surface : a
certain amount of heat is required to vaporise the liquid and
the hot surface may be cooled locally to such an extent that
insufficient steam is produced to support the drop and isolate
it from the plate. The palpitation of a drop spread on the
surface of a liquid is due to curious complicated changes in

35S

KNOWLEDGE.

September. 1911.

the surface tension due to gradual solution or to local cooling
as the case may be. It is well shown by a drop of
orthotoluidine containing paratoluidine.

Spherical drops of a liquid are sometimes formed dming a
distillation on the surface of the liquid which is being evapor-
ated. This, however, is a different affair, the retention of the
spherical form being probably due to some difference in
composition and hence surface tension of the liquid and the
drop.

Mr. Darling's experiments which have been recently
described in " Knowledge " show most beautilully the
gradual formation of a drop, which Professor Worthington
has studied on a smaller scale photographically. Mr.
Darling has devised a method of preserving a sphere of
one liquid in another of equal density. A beaker is filled
to two-thirds of its height with water at 22" C. : one
hundred centimetres of a three per cent, solution of
common salt are discharged at the bottom of the
beaUer. making thereby the lower layers of liquid slightly
denser. .\ large tap funnel containing orthotoluidine at about
20" is inserted so that the stem of the funnel is seven centi-
metres or so from the bottom of the beaker. By slowly
opening the tap the orthotoluidine will form a sphere of quite
eight centimetres in diameter suspended within the water and
can be shaken free from the stem.

Sulphur when heated on a glass slip, gathers itself into a
flat bottomed drop and does not wet the glass, residing on it
like a drop of mercury though not quite such a spherical drop
could be formed. The drop will solidify in the same shape
as it forms as a drop, but above 256" it begins to flatten and
'■ wet " the surface of the glass. The description of these
phenomena is due to Mr. W. A. D. Kudge.

In Mr. Darling's experiments on the formation of drops, as
the large sphere of aniline hits the bottom of the beaker it
flattens out into a disc-like form with rounded edges, in fact
the aniline at the bottom of the beaker takes up a shape
something like the small drop of sulphur in Mr. Kudge's
experiment.

There are many phenomena of a curious and interesting
nature connected with surface tension which it is well to call
attention to from time to time as their explanations are as yet
incompletely worked out.

ALLOTROPV. — Many substances can exist in more than
one form ; there are at least three distinct " allotropic " forms
in which sulphur can occur, or two in which phosphorus
exists, to take well-known examples. Thus sulphur exists in a
rhombic crystalline form melting at 112-8° C, and in a
monoclinic form melting somewhat higher, and being of a
browner hue and insoluble in carbon bisulphide. Further
there are other less distinct forms, such as colloidal sulphur
formed by precipitation of sulphur from thiosulphates bv
strong acids, and so on, or plastic sulphur which is an
extensible gummy brownish-yellow mass formed by suddenly
cooling liquid sulphur, and is the latter in a supercooled state,
which changes fairly rapidly into rhombic sulphur. .\ peculiar
gummy sticky variety of plastic sulphur rather different in
many respects to the other variety can be made by suddenly
cooling liquid sulphur by pouring it into liquid air. This
variety changes very rapidly, especially on touching it, into
very yellow rhombic sulphur.

Much work on allotropy and the ei|uilibrium between the
different forms of substances under different conditions of
temperature and pressure, has been done by Professor Cohen,
of Leyden, and his collaborators. Smits has recently published
a theory to explain the phenomenon of allotropy. In the
litjuid state a substance showing allotropy consists of two
kinds of molecules ; the number of one kind existing in
presence of the other depends on the temperature, and, at any
particular temperature, there exists an equilibrium between the
two kinds. On rapid cooling, all of the one form does not
change as the temperature falls, into the simpler form which is
stable at the lower temperatures, because the equilibrium
cannot keep pace with the change in temperature ; solidification
then occurs at a temperature differing from the solidification

point of one of the molecular forms. Thus if rhombic sulphur
be melted and allowed to cool to 90° C. so that equilibrium
sets in at this temperature and then is suddenly cooled, the
resulting sulphur melts at 110-9' C or, if equilibrium occurs
at 65°C. the melting point is 111-4°C. This points to the
existence of two kinds of molecules. In the case of phosphorus
which in the pure crystalline state, melts at 44° C. + -02° C,
the melting point is considerably affected by previous heating at
different temperatures, pointing to at least two different forms
of molecules being present ; the violet form, which is stable
below 460° C can be best accounted for by a discontinuity of
the series of mixed crystals of the yellow and red forms.
-Mercury exists in only one modification, which is in agreement
with its single molecular condition adduced from other con-
siderations. Tin and many other elements exist in more than
one form. The theory explains readily the phenomena of
undercooling and superheating such as occur during rapid
cooling and heating. Having mentioned superheating it is
interesting to note that the vapour pressure curve of solid
bromine, obtained recently by Cuthbertson by optical means,
shows evidence of superheating of this solid, the vapour pres-
sure being greater than that of the liquid above the real melting
point of the solid.

LIQUID HELIUM. — Kamerlingh Onnes has been making
further experiments with liquid helium ; he finds the density
at 4-29° from the absolute zero ( — 273-12-C.) to be 0-122
and the liquid appears to possess a maximum density at 2-2°.
He has also found that mercury when exposed to a tempera-
ture of 3 absolute, such as is produced by hquid helium
boiling under reduced pressure, has an exceedingly great
electrical conductivity : ten miUion times greater than at O-C;
which is rather a surprising result, considering that from the
temperature coefficient one would expect a resistance of
40 ohms, instead of 3 X 10"'' ohms ! Other properties, such as
magnetic susceptibility, are considerably altered by these very
low temperatures, though the electrical resistance of other
metals, such as silver, lead, eureka, and so on, is not modified
to anything like the same amount as that of mercury. Further
experiments to elicit the cause of the phenomena will be
awaited with interest.

UK-iVNIUM. — The name of Becquerel has been associated
with the study of phosphorescence for generations. M. J.
Becquerel has been studying for some time the effect of low
temperatures on phosphorescence which, in general, causes an
increase in the duration of the phosphorescence. However, he
finds that the low temperature does not affect the duration of
the phosphorescence of uranium nitrate and sulphate — the
most phosphorescent of uranium salts : while the acetate,
tartate, and so on, show nuich longer persistence of phosphor-
escence at low temperatures. Uranium nitrate exhibits
marked " triboluminescence " ; if a bottle of the nitrate be
shaken in the dark, flashes of light will be seen ; this is due to
cleavage of the crystals accompanied probably by minute
electrical discharges which excite the crystals to phosphoresce.
It is a very different phenomenon to the sparks of uranium
obtained by shaking a bottle of metallic uranium. The latter
is a " pyrophoric " property ; the uranium particles which are
struck off in the shaking actually burn in the air, owing to the
avidity with which uranium combines with oxygen ; the same
phenomenon is found with cerium and iron. I have been able
to run a petrol engine using these sparks as the igniting agent
for the explosive mixture, but I do not think the method a
practical one owing to the injury to the cylinder walls. The
triboluminescence of uranium salts is a very different affair
from the pyrophoric property of the metal : the tribolumin-
escence is unaffected by an atmosphere of hydrogen, while
the pyrophory no longer occurs.

Pitchblende is the main ore from which uranium is
obtained; it is also the chief source of radium. It is
noteworthy that H. Poole has found that the evolution of heat
by a mass of pitchblende is greater than would be expected
from its radium content, and the fact that radium generates
one hundred and ten calories per hour. The difference
between the observed heat generation and the calculated

September, 1911.

KNOWLEDGE.

359

appears greater than would be accounted for by the presence
of other radio-active substances such as uranium, thorium and
actinium, and might perhaps be due to the more complete
absorption of the radium rays in the mass of the pitchblende,
than occurs when a measurement of the heat production of
pure radium is made.

ZOOLOGY.

By Professor J. Arthur Thomson. M.A.

THE AW.AKENIXG HEDGEHOG:— When a hibernating
hedgehog awal<ens it rapidly warms itself up. Whether this
comes about automatically, or whether it is due to the
awakening animal "pulling itself together" seems to be a
moot point. The fact is that the animal rapidly warms itself
up. The chemistry of this, according to Tanzo Yoshida and
Ernst Weinland, is a rapid combustion of glycogen along with
a small or moderate quantity of fat. There seems no doubt
that the important fuel that so rapidly makes the fire of life
burn up is glycogen: the fat is only subsidiary. It must be
noticed that in the hedgehog the awakening and the warming-
up are two distinct, though associated, processes ; for the
animal maybe wide awake at a lower temperature.

VARIATIONS IN FOWLS' COMBS.— Poultry-breeders
know when a hen is going to begin to lay by a rapid and
marked increase in the size of the comb. Mr. Geoffrey Smith
has shown that this correspondence is exact both in young
and adult hens. There may be an increase of 130 per cent,
within three weeks, and this does not correspond with a
general increase in weight, though the latter usually precedes
it. After the laying period, there is a decrease in the comb
The cock's comb does not exhibit these marked fluctuations.

The increase is due to a fatty infiltration of the central
connective-tissue core of the comb, and the explanation of the
infiltration is to be found in the fact that at the egg-laying
periods the blood becomes charged with fatty material which
is conveyed to the ovary for the formation of yolk, the excess
being deposited in the comb, and probably in other situations.
Mr. Geoffrey Smith compares this with what occurs in a
spider-crab parasitised by Sacciiliiia ; the Saccidiiia " forces
the crabs to elaborate yolk-material ;" this circulates in the
blood ; it should be stored in the ovaries, but there are none,
because of the inhibiting influence of the SacciiliiKj, the yolk
material : it nevertheless acts as the stimulus for the develop-
ment of the adult female secondary sexual characters.

HORNBILL'S STOMACH.— Everyone knows of the
strange bag of indigestible debris which hornbills periodically
eject, but there is a lack of precision in the statements that
have been made. An interesting recent contribution by H. C.
Curl shows that the deciduous membrane in the great
Philippine hornbill. Hydrocorax Uydrocorax, studied outside
the breeding season, is a tough, homogeneous sac formed of
colloid material secreted by the glands of the stomach wall.

MOSQUITO SUCKED BY MIDGE.— F. H. Gravely
reports finding in the Sunderbunds a small Chironomid fly
iCiilicoidcs) with its proboscis well-embedded in the abdomen
of a mosquito ^Myzontyia rossii} and evidently imbibing

nourishment from it. Probably the Culicoides sucks
mammalian blood, and was taking it second-hand from the
mosquito.

A FRESHWATER RHIZOCEPHALOX.— Dr. Nelson
Annandale, Superintendent of the Indian Museum, describes a
very interesting animal, which he calls Sesannaxcuos
Dionticola g. et sp. n. It is somewhat like the well-known
SaccuUiia that occurs beneath the abdomen in shore crabs,
and it occurred in a similar position on a fresh water crab,
Scsanna thelxiiioc. in a jungle stream in the Andamans,
seven hundred feet abo\'e sea level. This is the only known
freshwater Rhizocephalon, and only the one specimen has
been found.

CAMBRIAN SEA-CUCUMBERS. — From the Middle
Cambrian, British Columbia. Charles D. Walcott describes
the first Holothuroids found as fossils. Some isolated
calcareous plates have been previously recorded, but now we
have entire animals. — unluckily without any calcareous plates.
The most remarkable type, which the discoverer calls Etdonia.
and describes as free-swimming, has some suggestion of a
medusa about it, but Dr. Walcott has given careful con-
sideration to that possibility. Trilobites, Phyllopods. and
Medusae were found in the near vicinity. .Again, we have
striking evidence that there must have been great steps in
animal evolution in PreCambrian and early Cambrian ages.

NOTES ON THE AFRICAN FRESHWATER
MEDUSOID L/.17A'0CiV/D^.— Charles L. Boulenger has
some interesting notes on this medusoid from Lake
Tanganyika. The stinging-cells of the tentacles are not
developed in situ, but in the ectoderm of the " nettle-ring,"
a thickening along the margin of the umbrella. This ring is a
factory and a storage- place of the stinging-cells and they
migrate thence to the tentacular batteries. There is a well-
developed double nerve-ring at the base of the velum, similar
in most respects to that of Liiniiocodiuin, and of other
medusoids. Mr. Boulenger shows that the manubrium is
undoubtedly functional as a digestive organ. The develop-
ment of the medusoid buds presents se\eral interesting features,
some of which are undoubtedly primitive.

A RE.MARKABLE SPONGE.— Mr. R. Kirkpatrick. of the
British Museum, gives a full and finely illustrated account of
Mcrlia nonnani. a sponge with a siliceous and calcareous
skeleton. It w^as found by Canon Norman, and subsequently
by Mr. Kirkpatrick, in sixty to ninety fathoms, off Madeira and
Porto Santo. The sponge character of the organism has
been called in question mainly, if not wholly, on a priori
grounds, but the author has examined five hundred specimens.
Dr. Weltner supposes that the calcareous structure is that of
an unknown organism in which a siliceous sponge has settled.
" If this be so," Mr. Kirkpatrick answers. " the said organism
has preserved its incognito in a marvellous manner." But we
do not follow his reasoning when he says : " If. as I believe,
Mcrlia is a siliceous sponge which has taken to forming a
calcareous skeleton, then this sponge furnishes a good example
of the hereditary transmission of an acquired character."
Taking to forming lime is not an " acquired character " in
the technical sense ; it was probably a constitutional variation.

THE BRITISH A.SSOCIATION.

This year's meeting will open on Wednesday, August 30th. at
Portsmouth, under the presidency of Professor Sir William
Ramsay, who will give his address in the Town Hall at
8.30 p.m. The Hampshire Post estimates that between
fifteen hundred and two thousand members will be present.
On Friday, September 1st, at 8.30 p.m.. the first Evening
Discourse will be delivered by Dr. Leonard Hill. F.R.S..
on '■ The Physiology of Submarine Work." On Monday,
September 4th, at 8.30 p.m., the second Evening Dis-
course will be delivered by Professor A. C. Seward, M.A.,
F.R.S., on " Links with the Past in the Plant World."

Of recent years there has been an outcry against the
papers being made so technical that local members, who
are not specialists, cannot appreciate them. It has been
customary for Section D (Zoology I to arrange a popular
lecture, and this year two appear in the programme, namely,
one on " Fairy Flies," by Mr. Fred Enock, and the other on
" Fossil Reptiles,'' by Dr. Andrews. "Rain" will be considered
by Dr. H. R. Mill in his lecture to the operative classes, and
some very attractive excursions have been arranged to
-Arundel Castle, to the New Forest, and to the Isle of
Wight.

THE FACE OF THE SKY FOR SEPTEMBER.

Bv \V. SILVCKLETOX. F.K..\.S.. A.R.C.Sc.

The Sun. — On the 1st the Sun rises at 5.13 and sets at 6.4S ;
on the 30th he rises at 5.58 and sets at 5.43. The Sun enters
the sign of Libra on the 24th at 4 a.m.. when autumn
commences. The equation of time is negligible on the 1st
and 2nd. hence these dates are convenient for the adjustment
of sun-dials, as only the longitude correction is needed. Sun-
spots and faculae are very sparse, although occasionally a
spotlet or a few faculic markings may be seen. The positions
of the Sun's axis, centre of the disc, and heliographic longitude
of the centre are given in the following table : —

Date.

Axis inclined
from N. point.

Centre of Disc

N. of Sun's

Equator.

Heliographic

Longitude of

Centre of Disc.

.Sept. 3 ...

21° 34'K

f .4'

299° 20'

8 ...

22° 44'E

f 15'

233° iS'

,, 13 •■•

23° 44'E

7° 1 3'

167° 17'

,, iS ...

24° 37'Ii

r 8'

lOl"" 16'

,, 23 ...

25° I9'E

■ 7° I'

K '7'

„ 28 ...

25° 5i'E

6° 49'

329° 17'

Oct. 3 ■

26° 13'E

6° 35'

263° 19'

8 ...

26° 2S'E

6° 18'

197° 20'

A suitable diagram, for this period, for the projection of the
solar disc is shown on page 310 of last month's issue.

The Moon : —

Date.

Phases.

H. M.

Sept. 8 ...

„ 15 ...

,, 22 ...

„ 30 ...

Oct. 8 ...

C Full Moon

(I Last Quarter

0 New Moon

J) First Quarter

0 Full Moon

3 57 pill-
5 5' P»i-
2 37 P-m-

II 8 a.m.

4 II a.m.

Sept. 2 ...
„ 17 ...
„ 30 ...

Apogee

Perigee

Apogee

7 iS a.m.
6 0 a m.
2 30 a.m.

OccuLT.^TiONS. — The only naked eye star occulted during
the present month and visible from Greenwich, is the 5i mag-
nitude star 43 Ophiuchi. The occultation occurs on Septem-
ber 1st, disappearance being at 7.58 p.m.. and re-appearance
at 8.4 p.m.

THE PLANETS.

Mercury

—

Date.

Kight .Ascension.

Declination.

Aug. 30 ...
Sept. 9 ...

„ 19 ...

„ 29 .,.
Oct. 9 ..

li. m.
11 30

II 3

10 46

11 19

12 20

S 1° 28'

N 2'^ 14'

7° i6'

\ 6" 6'

s 0° r

Mercury is in inferior conjunction with the Sun on the 9th.
.^fter this date the planet is a morning star in Leo and is at
greatest westerly elongation of 17^" 52' on the 25th, on which
date he rises at 4 a.m., or nearly two hours in advance of the

Sun. The elongation is thus a somewhat favourable one for
seeing the planet.

Venus :^—

Date.

Right Ascension.

Declination.

.Aug. 30 ..
Sept. 9 ...

,, 19 -...

„ 29 ...
Oct, 9 ...

h. ni.

II 45
11 28

II 7

10 52
10 52

S 6° 14'

5" 53'

3" 30'

S tf-' 26'

N 1° 50'

Venus is in inferior conjunction with the Sun on September
15th, and throughout the month is unobservable, as she
appears too near the Sun.

NL\RS : —

Date.

Right .Ascension.

Declination,

Aug. 30 ...
Sept 9 ..

„ 19 ...

„ 29 ...
Oct. 9 ...

h. m,

3 41

4 "
4 16

4 28

4 36

N 17° 42'
18° 49'

19° 44'

20° 28'

N 2i>-' 3'

Mars is an evening star, rising N,E, by East at 9,30 p.m.. on
the 1st, and at S p.m. on the 30th. The planet appears
between .Aldebaran and the Pleiades, somewhat nearer the
former.

The planet is becoming more favourably placed for observa-
tion and is increasing in brightness, the apparent diameter of
the disc increasing from 11" -4 to 14"-0 during September.

As seen in the telescope the planet appears gibbous, l"-6
of the disc being unilluminated. The south polar cap is \isible
and appears fairly bright ; but other markings are difficult to
delineate in telescopes of three or four inches aperture, even
if powers of two hundred or three hundred be used,

Jupiter : —

Date.

Right .Ascension.

Declination.

h. 111.

Aug. 30 ...

14 29

S 13° 44'

Sept. 9 ■■•

14 35

14° IS'

,, 19 •••

14 42

14" 4S'

,, 29 ...

14 49

15° 23'

Oct. 9 ...

14 57

S 15° 59'

Jupiter is an evening star setting \\'.S.\\'. at 8.45 p.m., on
the 1st and at 7 p,m, on the 30th, The planet is very little
observable as he is rather low down at sunset, and is soon
lost to view in the evening ha^e.

No satellite phenomena are observable, as the planet appears
in too bright a portion of the sky when any of the transits or
eclipses occur.

The configurations of the Satellites as seen in an inverting
telescope and observing at 7 p.m. are as follows : —

360

September, 1911.

KNOWLEDGE.

361

Day.

West.

East.

Day.

West.

En St.

I

2

0

134

16

2^1 0

4

2

32

0

4 •!

17

3 0

24

3

31

0

42

IS

3 0

124

4

34

0

21

1 19

213 0

4

5

421

0

3

20

2 C\

'3

6

4

0

13 02

21

41 c

23

7

41

0

23

22

42 ^

'3

S

42

0

13

23

4213

9

4»I

C)

24

43 '

12

10

51

u

2

25

43 (-'

• i

II

34

0

1

2(1

4231 ('

12

213

0

4

27

42 (J

13

'3

0

134 92

2!S

14 U

23

14

I

u

234

2Q

0

.>

15

2

u

134 1

1

30

21 0

4

Uranus:

The circle (O' represents Jupiter; 0 signifies that the
Satellite is on the disc ; • signifies that the Satellite is behind
the disc or in the shadow. The nnmbers are the numbers of
the Satellites.

S.\TURN : —

Date.

Right Ascension.

Declination.

Sept. I ..
., 16 ...

Oct. I . .

b. m.
3 14
3 13
3 II

N 15° 20'

15" 23'

N 15" !2'

Saturn rises in the E.N.E. at 9.10 p.m. on September 1st,
and at 7.10 p.m. October 1st. The planet appears as a
conspicuous object in the evening sky looking East, and is
situated about midway between Aldebaran and a .-^rietis,
where he may be observed shining as a bright star free from
scintillation, but with a peculiar lustre which has given it the
name of the Leaden Planet. 1 he telescope view of the
planet with his rings is superb, and even when other objects
are difficult to define. Saturn exhibits crisp detail, well
repaying observation. The ring is visible in quite small tele-
scopes, such as an ordinary good deer-stalker, with a high
power eyepiece, and in a good three-inch telescope the ring is
visible with a power of about fifty, and the belts on the
planet's surface with a power of about eighty ; using higher
powers the division in the ring may be seen. The diameter of
the outer major and minor axes of the ring system are
respectively 45" and 17", so that the ring appears well open,
being inclined to our line of \ision at an angle of 22 , the
southern surface being visible.

The planet has eight satellites: of these, Titan, (mag. S-5)
can be observed with a good objective of two inches aperture,
lapetus (mag. 9-12) maybe seen at his westerly elongations
with a telescope of three inches aperture, which is also
sufficent to show Rhea (mag. 9-5) and Tethys (mag. 10) whilst
Dione (mag. 10-5) requires an aperture of four inches. The
three other satellites require larger telescopes, since their
magnitude is less than twelve.

Dale.

Right Ascension.

Declination.

Sept. I ...
Oct. I ...

h. m. s.
19 51 55
19 49 57

S 21' 32' 0"
S 21" 36' 39"

Uranus though rather low down in the sky, is fairly well
placed for observation during the early evening, and is due
South shortly after dusk. The planet is situated in Capricorn
in a part of the sky devoid of good reference stars, though
the star o- Capricorni is about 2° to the N.E. The planet
is at the stationary point on the 6th October, after which his
motion is direct or Easterly.

Uranus can just be discerned with the naked eye on clear
nights, but the slightest optical aid is sufficient to make the
planet clearly visible.

The planet is in conjunction with the moon at 4.37 p.m. on
the 4th. Uranus being 4i" to the north.

Neptune

—

Date.

Right .\scension.

Declination.

Sept. I ...
Oct. I ...

h. 111. s.
7 3*^ 40
7 41 26

N 20° 56' 10"
N 20>^ 49' 23"

Neptune does not rise till midnight on the 12th : thus for all
practical purposes the planet is unobservable.

Meteors : —

Date.

Radiant.

R.A.

Dec.

Sept. 3-S.-.
„ 5-15^

., 21-2;...

353^^

02'^

N- 39"
N- 37'

X- 43

1' .\iidroiiiedids. Very swift.
e Perseids. Swift, bright

streaks,
f-j .\urij;ids. \'eiy swift.

Minima of Algol occur on the 2nd at 7 p.m., and on the
22nd at 8.30 p.m.

1 he period is 2'' 20"^ 49'", from which other minima may be
calculated.

Telescopic Objects: —

Double St.\rs.— f Ursae Majoris XIII." 20'", N. 55" 23'.
mags. 2. 4 ; separation, 14"4.

j-Aquarii X.XII.'' 24"", S. 0' 32', mags. 4. 4; separation,
2"'9. Both components are yellowish.

(5 Cygni .XIX." 27"", N. 27° 46', mags. 3. 5 ; separation, 34".
The brighter component is yellow, the other blue ; very easy
double in small telescopes with a power of 20.

Cluster (M 11) in Aqiiila or Antinous. R.A. IS'* 46"";
Dec. S. 6° 2i'. Very pretty object for three or four-inch
telescopes : it is an easily resolvable fan-shaped cluster, with
an eighth magnitude star in apex and an open pair of the
same magnitude just outside it.

THE BRENT \'.\LLEV BIRD SANCTUARY.

A MOST successful season has been experienced in the Bird
Sanctuary, and even now there is still (.August 2Sth) a
bullfinch's nest containing eggs. It has been suggested by
Mr. Robert Read, M.B.O.U.. that it may have been built
by a pair of this year's birds, and should they prove to be
poorly coloured it will be additional evidence in favour of
the supposition being correct. The nesting boxes made from
logs similar to those illustrated and described in the .^pril
number of " Knowledge," which were tested, were with
very few exceptions tenanted, though many were put in

(juite exposed situations. A large number of these boxes
which were sold were also used to good effect in the
majority of cases, and the profits have been applied to the
upl<eep of the Sanctuary. The wood is interesting at all
times of the year, and during the past week the following
birds have been seen : Kestrels, green and greater spotted
woodpeckers, nightjar, kingfisher and turtle dove. The
Honorary Secretary of the Committee is Mrs. Wilfred
Mark Webb, and her address is "' Odstock," Hanwell,
London, W.

THE NEW ASTRONOMY.

I. THE ST()R\' OI- XO\'A 1'P':RS[:1.

Bv PKUFKSSUR A. W. 1;KK1:KT( )X.

As the twentieth century dawned, an astronomiral
event occurred that had not had its equal in the
history of celestial obser\ation for some three
hundred }-ears. A brilliant temporar\- star suddenh-
blazed out in the Northern hemisphere, and as these
evanescent flashes are called Nova or New Stars.
this star was called the New Star of the New-
Century, and because it was in the constellation of
Perseus, it was called No\-a Persei.

Nothing in the whole realm of Nature is so wonder-
ful as this event, the bursting out of a giant sun. its
then increasing with amazing rapidity, until it is
sometimes many scores of thousands of times the
brilliancy of the magnihccnt luminarv that keeps the
earth in its orbit.

.And no other celestial e\ent has so fascinated the
minds of men, and drawn them to study the heavens,
as these exploding suns. It was one of these
lirilliant portents that caused Hipparchus to draw
up his historic list of the stars. It was another that
caused Tycho Brahe to lea\e the lamps and furnaces
of his laboratory, and come out into the open to
study the celestial vault and make his wonderful
measurement of the places of the planets. It was a
temporary star that drew Galileo into that war of
words and wonder of achievement and ideas that
cost him so much, and also made him teach the
Copernican doctrine of the moving earth.

And again this year, the new star in the constella-
tion Lacerta, discovered by Mr. Espin, has caused an
immense amount of discussion not mereh' amongst
the learned societies, but even in the popular
newspapers all over the world. It is commonh-
thought that the star of Bethlehem was a new one.

Speaking of these flashing bodies the late Professor
Newcomb says: — "The so-called new stars which
blaze forth from time to time, offer to our sight the
most astounding phenomena ever presented to the
physical philosopher." Carl Snyder sa)-s : — " Could
they be closely regarded, the blazing up of these
novae would doubtless be, in mere extent, the most
impressive spectacle the realms of Nature afford."
That very able astronomer, the late Miss Agnes
Clarke sa}-s : — " What they w ere. w hat they are.
what they become, are all difficult questions to
answer. But the crux of the whole problem
concerns the manner of their vivification. A bod\-
previously inert is transformed wellnigh instan-
taneously into a radiative centre of immeasurable
intensity. How is the change effected ? "

No human being is capable of conceiving the
vastness of this phenomena. To us. the earth is an

immense body : we know it weighs more than six
thousand million of million of million of tons. Our
Sun is more than a million times the size of the
Earth, and those vast globes of fire must often be
man\- scores of thousands of times the volume of the

Sun. Yet Nc

Persei rose from invisibilit\' to its

maximum in less than fortv-eight hours, and in a
few months was again in\'isible to the naked eye.
The stupendous nature of the phenomena and their
evanescent character constitutes their chief wonder.
Newcombe speaks of their impenetrable mystery.
He says : — " The cause of these outbursts is a
question of transcendent interest, the answer to
which science has not up to the present time been
able to ofter any suggestions not open to question."
Miss Agnes Clarke says: — "That even the most
promising explanation is not mereh' unscientific, but
outrageous to common sense."

There are an immense number of explanatorx'
suggestions in various books on astronom\-. all of
which are absolutely puerile when we regard the
insufficiency of energy to explain the phenomena.
The question then occurs. Can anv solution to their
mystery be suggested ? Is there any storehouse of
energy that can be laid under contribution to supph'
fuel for so stupendous a conflagration ? And the
answer is clear and explicit. There is.

In the collisions of suns, we have a sufticienc\- of
energy to account for the whole phenomena. Hence
a detailed study of the phenomena of solar collisions
offers the most promising ground for the solution of
the mystery of these immeasurable conflagrations.

Imp.vct, a Law of Nature.

A very superficial study shows us that solar
collisions cannot be looked upon as accidental,
chance, or mere random occurrences. Mutual
attraction, and many other agencies, something like
a dozen in all, have been investigated, and the
conclusion is forced upon us that the number of
solar impacts that must be produced b}' these
many agents are hundreds of thousands of times
more numerous than mere random encounters.
The next thing that shows itself in our investi-
gations is, that not one of all these collisions that
are brought about by attraction, and so on, can be a
direct centre-to-centre impact. The bodies must
move in curved orbits, and hence the collisions so
produced must be of a tangential or grazing character.

It was also shown that the extreme velocities
produced by attraction in all cases of colliding suns
must be of the order of hundreds of miles a second.

362

SEPTEMnF.R, 1911.

KNOWLEDGE.

363

Figure 1.

A pair of Stars distorted
coining into impact.

and

That is. if trains possessed this velocity, their
coHision would have an energy hundreds of miUions
of times greater than that of colHding express trains.
It cannot be imagined that a shght graze of suns
passing one an-
other N\ith these
speeds will stoti
them. The porti(_ .1
actualh' in one
another's paths
\\ill be shorn a\\a\-,
and the torn suns
will proceed on
their journey with
orbits modified bv the
attraction of the newly-
formed third star. The
phenomena of these
torn suns may be
of the most varied
character. They ex-
plain many of the
characteristics of the
wonder stars and
double stars of the heavens. In
telling the stor\' of Nova Persei
the\' do not greath' concern us,
but must be referred to when we
study the wonderful spread of light
that flashed through the previously
existing nebula, at whose centre
Nova Persei appeared.

Figure 2.
A pair of Stars in impact.

Figure

The Theory of the Third
Body.

It is the properties of the coalesced portion torn
from the two passing suns, that correspond with, and
explain in the minutest detail, every one of the
multifarious observations that astronomers have
made of Nova Persei. The deductions that
explain these observations were published fully a
score of vears before the wondrous star appeared.

The accompanving Figures (1-5) have been photo-
graphed from diagrams made and published more
than thirty years ago. and show kinematically the
progress of an impact during its first few hours.
Eigure 4 is probabh' the most instructive of the
whole, because it shows not merely the form and
motion of the third body, but also the distribution
of the adherent heated matter, clinging to the two
retreating suns.

The most important characteristic of this third
body is its stupendous, its absolutely abnormal and
explosive energy. Ritter and myself have shown
that the energy of the critical velocity of a pair of
similar completeh" colliding gaseous suns, is exactly
one half of that necessary to produce an infinitely
diffused nebula. It must be remembered that similar
chemical elements, colliding with similar velocities,
produce the same temperature, and hence, however
small the portion torn away, if it be of the same
composition, whether small or large, it will have the

1 he Stars passing ont of impact, and
G3 the formation of a third bodv.

same temperature as though tiiere were a complete
collision. Thus, contrasting a complete collision
with a graze of one-tenth, in the one case we have
the whole matter heated to a certain temperature
and in the other case, one-tenth is heated to the
same temperature. In the third body there is one
tcntli the mass, and one tenth the heat ; hence the
temperature is the same as with complete collision.
The speed of a particle possessing sufficient power
to enable it to escape completely from a body, is
called the critical velocity. Now the critical velocity
depends to a large extent on the mass of the attract-
ing body. Thus a body ha\-ing a velocity of one-and-
a-half-miles a second could escape the moon, a
particle with a speed of seven miles a second
could escape the earth : whilst an asteroid
requires to ha\e a velocity much over three
hundred miles a second to entirely escape the
sun. Consequentl}' with two bodies of the
same temperature and different mass the
molecules may move fast enough to get entirely
free from the bodv of small mass, and be
retained by the body of large mass. The
third body is a small mass at an exceedingly
high temperature, as high as if the
whole of the two suns had collided,
and hence, if it he onl\- one-tenth
of the mass of a sun formed by
complete collision, this third star
possesses man\- times more energy
than is necessary to make it
explode.

The new star formed bv a

zing collision of suns, being ex-

Flci'Rii 4.

Showing entanglement of matter in
each bodv.

once begins to
expand at some-
thing like a
million miles an
h our. W h e n
first formed it
is a bod\' of
a s t o n i s h i n g
brilliancy, and
as this vast bon-
fire grows it
becomes more
and more bril-
liant. Themaxi-
mum of bril-
lianc\- is quickly
reached, but the
velocit\' of the
particles has
scarcely dimin-
ished at all, and
so they go diffusing in space, until the mass forms
a rare nebula ; the luminosit\' gradualh" dim-
inishing from maximum until the star becomes
in\isible to the naked e\e. The great energv
of the molecules is not equally distributed
amongst the elements, for it is a property of
molecules that when at the same temperature each

Figure 5.
Two variables and a temporary Star.

364

KNOWLEDGE.

Skpti;mi!Er. 1011.

atom possesses the same energy. An atom of lead
weighs two hundred and seven times as much as an
atom of hydrogen, and }-et when both the atoms are at
the same temperature each has the same energy : one
has great mass, the other great velocity. Immediate!}-
after the collision all the elements have the same
velocity, that is at the moment of the formation of
the third body, lead is excessively hot. and h\drogen
much cooler. As equality of temperature is gained,
the h\-drogen robs the heavier elements of their
energy, and may attain an extraordinary velocity.
The velocity of hydrogen actually recorded in the
case of Nova Persei, was fully a thousand miles
a second. In this way the light gases escape
away from the heavier
ones, and leave them
behind, the light elements
forming vast ensphering
shells constanth' expand-
ing outwards. The heavy
gases tend to form an
intensely brilliant nucleus,
that has not sufficient
energy for complete dissi-
pation. Hence there is a
limit to its expansion. But
the outward momentum
of the particles will carr\-
them beyond the limit of
equilibrium. When the\'
come to rest, gravitation
will cause the mass to
shrink again: as it
shrinks it will increase in
brillianc)- ; but again

7 9 11

I-IGURE 6.

tht

momentum

.f the

molecules will carry them past the position of
equilibrium, and this oscillation may go on for an
indefinite number of times, until an approximate
balance is obtained. This balance is not one of
rest ; for, as will be show n immediatelv. the third
body must be in a rapid state of rotation, due to the
conflicting forces of impact. Let us examine the
light curve of the third bod\- and we shall see that
the curve deduced by dynamical reasoning (see
Figure 9) is absolutely similar in every respect to
the curve drawn at South Kensington, from actual
observation of Nova Persei.

Calculation shows the imjiact, that is, the initial
explosion, takes an hour, and the body is at once
of transcendent brilliancy. It then expands with
extreme rapidity, hence the light curve to commence
with is almost vertical. It increases with great
speed for a short time, remains for a while
approximately at the same height, and then begins
to fall, falling much more slowl}- than it rose.
Presently contraction sets in, during which time
the curve rises, because, under the influence of
pressure, the light becomes more intense. Then
again expansion ensues with lessened luminosity.
to be again followed with another period of com-
pression, with increased light, .^nd so the curve
continues to oscillate for a period that is dependent

on a \-ast number of special circumstances, which
must vary with each nova. In the case of Nova
Persei the oscillations were very long sustained.

The Foinr (_)F the Third Body and its

ROT.\TIOX.

It will readily be seen that the light gases on the
outside of the two impacting suns will be the first
to meet, hence, as the material crowds in upon itself,
this light material will, when the body is first formed,
be at its centre. As we examine the effect of the
collision on each of the two suns, we see that it
must form a long valley in each ; this valley
graduall\- becoming deeper and deeper. As the two

torn suns leave each other,
the material deep down
in its mass will be dragged
along, and much of it
will be left adhering to
the end of the vast valley,
that has been cut in each
sun. As the suns leave
one another the new third
body stretches out into
the spindle form, and the
distribution of material
will now be that the
lightest elements will be at
its centre, the somewhat
-- . . heavier ones will surround
o "20 ^e^^hn these light gases, whilst

Yb K'n7rrh the heaviest portion of the
third bod\- will be at the
ends of the spindle. These
ends may consist of elements whose atomic weight
will seldom be less than fort\' or more than seventy.
The reason it will not contain very heavy elements
is because, for various reasons, it can be show n that
when there is an exceedingly deep graze the three
bodiesdo not part company, but form a rapidly rotating
mass, that is probabh' what is known as a Wolf-
Rayet star. I have named such a deep collision a
case of Whirling Coalescence. Owing to this fact
of the difference of the quantity of material meeting
on opposite sides, the third star is set rotating. The
mountainous mass of material left on each of the
torn suns also in these scarred globes produces
rotation. These complex phenomena explain man\-
characteristics of variable stars, not howe\-er of
interest in connection with Nova Persei. This
peculiar property possessed by the light gases, of
sorting themselves into concentric shells according
to their speeds, we have called Atom Sorting or
Selective Molecular Escape. The principle here
introduced was fully studied in 1878, and the late
Dr. Johnstone Stoney devoted a considerable amount
of time to showing its influence with regard to
h\drogen and other
atmosphere.

The principle is of supreme importance in
connection with tiie impact theory of cosmic
e\i)lutiiiii. and must be clearly understood. To

I? 14 ,6
Atomic Kiiictol

ight elements, m our

September. 1911.

KNOWLEDGE.

365

simplify the conception a new dynamical term is
necessar\- ; it is an expression for the amount of
energs- that is possessed b\- a unit mass of any bod\-.

The necessity for, and the

meaning of, the term is
fully discussed on pages
15. 16 and 17 of " Tlie
Birth of Worlds and
S\-stems,"" in Har[)er's
Lil)rar\- of Li\iiig
Thought. The new term
is Kinetol. The kinetol
possessed by monatomic
molecules of the different
elements when at the
same temperature, is
inversely as their atomic
weight. Thus, the kinetol
taken as unity, the kinetol of
of owgen would be

Figure 7.
Part of a spectrum of Nova
Persei taken on the 5th of
March, 1901, at South Ken-
sington, and reproduced by
kind permission of Sir Norman
Lockyer, from his paper in
the "Proceedings of the Royal
Society," Volume 68.

of hs'drogen being
helium would be one-fourth
one-sixteenth and lead one
two-hundredth-and-seventh
part. The diagram (see
Figure 6) re[)resents the
atomic kinetol of some of
the lighter elements. Popu-
larl\- speaking, kinetol is the
jiowerto escapefrom a force.

The spectra of the stars
shows that hydrogen is
altogether the most
prominent element that
exhibits itself, and con-
sequenth- h}'drogen is the
element which is most
important to stud\-.

It is probable that in
almost all grazing impacts
hydrogen will possess from
fifty to a hundred times
the kinetol necessary for
it to completeh" escape
the attraction of the third
body. The whole work
that it will do in com-
pletely escaping will not
lessen its velocit\- one
per cent. This fact
furnishes a complete ex-
planation of the phenom-
enon that has proved so
puzzling in connection
with the retention of
velocit\' as shown b\' the
spectrum of hydrogen in
Nova Persei and other
new stars.

The Series of Spectra
OF the Third Body.

deduced light curves of the third bod}' and
the observed light curve ot Nova Persei. The
contrasted series of spectra are of much greater
complexity, yet show the same actual identity
of character. On the one hand, there is not
a single observation in all the spectrograms that has
not been dynamically deduced. And, on the other
hand, although the observation of no single obser-
\ator\- seems to satisfy all the deductions made,
\et, taking the whole world, the observations leave
but little to be discovered. There are still a few-
minor deductions remaining to be confirmed by
observation. Let us examine the salient charac-
teristic of the spectra that must be produced by the
successive phenomena of the third bodw Clearly
at first a mass so hot and under such stupendous
pressure will give a continuous spectrum. Presently,
as h\drogen escapes from the interior and forms a
close atmosphere, the continuous spectrum will be
crossed with black absorption lines of hydrogen.

Figure S.
It has already been shown photographs of the Spectrum of Nova Persei, 1901, taken at Stonyhurst College Observatory,

and copied from a Plate in " Knowledge " for January, 1902.

how exactl\- similar are the

366

KNOWLEDGE.

Septkmuer. I'tll.

Soon, however, the h\-drogen escapes and becomes
free, and forms an ensphering shell many diameters
of that of the brilliant nucleus of hea\\' matter. This
brilliant gas shell, as it is expanding in all directions,
is moving at e\er\- angle to the line of sight, both
from and towards us. Hence what would, were the
gas in a fixed position, be a bright line, becomes an
exceedingly broad band, indicating at its extreme
edgesatomic \-elocities of a thousand miles awa\- from
and towards us. Hence we now have a continuous
spectrum covered with brilliant bands of the
h\drogen series. But the part of the shell of
h_\drogen that is immediateh- in front of the

atmospheric coiulitions do not seem to have been
satisfactorv at South Kensington, when these stages
of Nova Persci occurred ; but they show themselves
beautifully in the Sttmyhurst spectograms. Father
Sidgreaves,the eminent astronomer of Stonyhurst,has
stated : — " That he has no doubt at all but that Nova
Persei actually was the third body, torn from a pair of
colliding suns."' He is quite opposed to the opinion
ex))ressed b\" some astronomers in The Times, that
the phenomena of No\'a Persei might be thought to
be explained b\- the idea of a dense body passing into
a nebula. He sa\'S the light could not grow up so
suddenK. It would take an ordinarv star fully a

Time.

Figure 9. Deduced Light curve of the Third Body.

brilliant nucleus, must absorb its isochromatic ra\s
and produce re\-ersion. The hydrogen coming our
way has its wave length shortened, that is, displaced
towards the violet ; consequently each one of these
bright bands will have a dark band edging it, on the
side towards the violet. Many observatories all o\-er
the world obtained spectrograms of No\a Persei, when
it was exhibiting this spectrum. Those of South
Kensington and Stonyhurst were both singularly per-
fect, and examples are given here (see F"igures 7 and 8),
and it will be seen that observation exactly corresponds
with deduction. The next deduced change in the
spectrum of the third body will be that as the speed
of expansion of the ensphering shell does not appre-
ciabh' diminish, the ratio of the portion of the sphere
that is in front of the absorption nucleus must get to
be extremely small. Consequenth" the dark lines
edging the bright bands, although the\' will not alter
their position, w ill become exceedingl}' thin and hair
like. Later on, the tenuity of the gas shell will be
so extreme that it will possess no absorbing power
and will disappear. .\ little later on the vast
ensphering shells of hydrogen will become so rare,
that molecular encounter will diminish so much that
the lessened luminosit\ will cease to photograph
itself, and so the bright bands will die out. The

thousand years to pass from the outside to the
centre of the No\'a Persei nebula, whereas Nova
Persei rose to a maximum in less than two da\'s.
This rapidit}- of formation renders it certain that if
Nova Persei was the result of any kind of collision, it
must have been the collision of compact bodies.
There are fulh' a dozen other points of coincidence
between deduced and observed spectral phenomena,
but there are twd that are extremely interesting and
about which we must say a few words. For various
physical reasons, already hinted at, I assumed that
the ends of the s})indle would consist of elements
having atomic w eights ajjiiroximately that of iron and
titanium, and because iron was a \er\' abundant
element in nature, I thought that the spindle ends
would largeh- be made up of iron. Of course, the
speed of the iron molecules would be much less than
that of hxdrogen, but as hxdrogen was not escaping
from the ends of the siiindle, the iron would not
have its kinetol lessened, and because its light would
not pass in front of the nucleus, save under verj'
exceptional conditions, the lines of iron would not
have a shadow band on the end towards the violet,
and would be moderateh' broad. \et not as broad
as hydrogen. Figure 7 (given on page J65) shows
[lart of a South Kensington spectrogram, a set of

September. 1911.

KNOWLEDGE.

367

exactly such lines. On inquiry I ascertained from
the observers at South Kensington that man\- of
these lines certainly did come from iron, and there
were also some that came from titanium.

The observers at South Kensington noticed a
remarkable fact with regard to the broad hydrogen
lines. Thev seemed streak\- : towards the edges
there seemed to be especial bands of greater
intensity. In the theory of the third body, I have
shown there is a line along \shich, in both directions,
gas will be extruded. Axial Extrusion is the name
we have given to this phenomenon. In the stud\- of
the origin of the universe, it is assumed to account
for the origin of the white polar nebula that is dis-
tributed at each of the poles of the Milk\' \\'a\".
This principle also permits the hydrogen gas that is
compressed at the centre of the third body to be
expelled in the two directions polar to the
plane of rotation. Doubtless it is these two vast
streams of ejected hydrogen that give these two
ribbons of intensity on the broad hydrogen
bands. The obser\ers at South Kensington
also noticed minor ribbons of luminosity, and a
careful study of the form of the third body
shows other weak places, where, in a less effective

way, hydrogen may be sent out as vast streamers.
There are quite a sheaf of other points of interest
and coincidences, and some show themselves in
connection with the pre-existing more or less
annular spiral nebula that was lit up by the flash of
Nova Persei, and that showed itself progressively in
extending circumferences. Light, with its speed of
one hundred and eighty-six thousand miles a second,
for months progressively lit up the coils of that
stupendous nebula, which I believe had been left
behind in a previous impact of the same two
gigantic suns, that by recurrent impact had pro-
duced the flash of Nova Persei. Deduction suggested
also that extruded gas from the third body should
generally pass through the stage of being a planetary
nebula. And here, again, we have the same
coincidences, but our account is already too long
and we must conclude by stating that from its
extreme brilliancy and its evanescence. Nova Persei
was almost certainly formed by a very small ratio
graze of two extremeh" massive suns, whilst Nova
Aurigae was a moderately-deep graze of suns of much
smaller mass. In the next number the coincidences
of astronomical phenomena, with the deductions
relating to the two torn suns, w ill be debated.

CYTOLOGY AND EMHRYOLOGY 1\ THE EN'CYCLOPAEDl.A

BRITAXNICA.

The scientific articles in the last edition of "The Encyclo-
paedia Britannica " cannot fail to be of the greatest interest to
the readers of this journal. They are clear and concise, and
thoroughly up-to-date. That on Cytology, is of the highest
importance, for " it is to the cell that the study of every bodily
function sooner or later drives us." Space will only permit us
to refer to one of the many interesting points elucidated in
this article. \'arious views have been expressed as to which
of the complicated processes which take place during nuclear
division is fundamental and initiative. " The experiments
of T. H. Morgan and E. B. Wilson, in which numerous
centrosomes and asters are caused to appear in unfertilised
sea-urchin eggs by a brief immersion in a 13 per cent, solution
of magnesium chloride in sea-water, as also the possibility in
many cases that even in normal fertilisation the cleavage
centrosomes may arise de novo, make it no longer possible to
regard the centrosome as a permanent cell-structure." " In
the spermatogenic cells of Ascaris, A. Brauer has shown that
the chromatin granules divide while still scattered over the
nuclear reticulum and before either the formation of a spireme
thread or the division of the centrosome." Clearly then, the
formation of the achromatic spindle has for its purpose, not the
division of the chromatin, for this has already occurred, but
its distribution to the two daughter nuclei.

The article on Embryology is likewise full of interest. The
question of the determination of sex has been much debated,
but the balance of evidence, we are told, appears to favour

the view that sex is an unalterable inborn character and does
not depend on nutrition or other external condition. " Thus
those twins which are believed to come from a splitygote
are always of the same sex, members of the same litter which
have been submitted to exactly similar conditions are
of different sexes, and all attempts to determine the sex
of the offspring in the higher animals by treatment have
failed."

Various structures and organs appear during development
to disappear again without representation in the adult form,
but the writer of the article on Embryology gives Uttle (luarter
to the recapitulation theory which attempts to explain this by
asserting that the embryonic history of the individual is but a
shortened Recapitulation of the ancestral history or history of
the race. " A disappearing adult organ is not retained in a
relatively greater development by an organism in the earlier
stages of its individual growth unless it is of functional
importance to the young form." Gills, for instance, are
retained in the tadpole while they are lost in the frog,
because they are of use to the tadpole, that is, to the larval
form. Where organs are retained in a better developed state
in the embryo than in the adult, it is simply because they have
been of use to the ancestors in their larval form, though of
no use to them in the adult, and have become in this way
impressed upon their development ; and only if they ha\ e been
of value to the larval form in former generations is there any
possibility of their retention.

REVIEW'S.

CHF-MISTKV.

Tniiiiiphs and Wonders of iJoilcnt Chemistry. — By

Geoffri;v Martin, B.Sc. M.Sc. Ph.D. 358 pages.

76 illustrations. S-in. X 5:l-in.

(Sampson Low. Marston & Co. Price 7 6 net.l

No one need accnse Chemistry of being a dry subject after
reading this bool< of Dr. Martin, with its wealth of illustrative
detail and its power of stimulating the imagination of ihe
reader. Obviously it has not been written with the aim of
scoring marks in the examination schools, and the author is
therefore at liberty to dwell upon matters of interest which
would not " pay " if regarded from that utilitarian point of view.
There is nothing in the book that need be beyond the grasp of
those who have no previous knowledge of chemistry, while the
chetnist may learn much by reading the author's vivid
descriptions of the most recent chemical theories and their
industrial applications.

The book opens with a chapter upon the mystery of matter,
in which are ably summarised the principal theories as to
nature of the atoms, and this is followed by chapters dealing
with the properties of the atoms, the evolution of the elements,
and the nature of chemical reaction.

Then come separate chapters upon water, air and some of
the principal elements, including hydrogen, oxygen, nitrogen,
sulphur, carbon and phosphorus, and the book concludes with
an admirable account of fire, flame, and the principles of
spectroscopic examination. .As instances of the manner in
which the book has been brought up-to-date it may be
mentioned that the latest theories upon radio-activity are
discussed, and that there is a capital description with
illustrative photographs of the industrial methods of fixing
nitrogen from the air.

Quotations from the poets and from the whole range of
ancient and modern literature are found in plenty all through
the book, and help not a little in the author's successful
endeavour to make the science a living thing. If we may
venture upon a criticism, however, we cannot help feeling that
in many cases the author's illustrative analogies fall wide of
the mark. For example, the comparison between the combin-
ations of atoms in a chemical reaction with the coming
together of the partners in a ballroom appears forced, and
does not help to make the subject any clearer. The book is
abundantly illustrated with excellent photographs, and with
numerous sketches. It is a pity that most of the latter are
out of drawing and in a future edition the author would be
well advised to have them redrawn by an artist.

These are minor drawbacks, however, and taking the book
as a whole we can warmly recommend it either as a present
that will give pleasure to a boy or a girl, or as a reliable and
most readable source of information for everyone who is
anxious to know something of the constitution of the world in
which we li\e. ,- < m

The Plmsc Rule and its App!icatii>ns. — By .\. KindlaV,

M..-\., U.Sc. Text Books of Physical Chemistry. j56 pages,

134 illustrations. 7A-in.x5-in.

(Longmans. Green & Co. Price 6 -.)

For the information of the non-chemical reader it may be
explained that according to the phase rule of the late Professor
(iibbs, the conditions of equilibrium in a given system of
substances depend upon the relationship between the number
of phases and of components simultaneously present. For
example, ice, water and water vapour are different pliascs of

the same substance — water; and may co-exist as different
phases in a system.

When first the phase rule, which has proved so fruitful of
result in the study of solution and chemical re.iction. was
enunciated, it was expressed in such mathematical terms as to
be grasped only by those with a mathematical training, and
the author of this book is to be congratulated upon the very
lucid way in which he has presented a complex subject in a
non-mathematical shape. Every step is made abundantly
clear and each difficulty is smoothed away, and the student of
chemistry or metallurgy whose work invoh'es a knowledge of
this branch of physical chemistry cannot do better than
procure a copy of this exceedingly useful text book. It has
deservedh' reached its third edition, and has been brought
up-to-date, so as to embody the results of the most recent
researches upon such subjects as the metastability of metals.

C. A. M.
BOT.AXY.

Bntisli Plants — Their Tiii>logv and Ecologv- — By J. F.

Bevis. B..A.. B.Sc, and H. j". Jeffery, A.R.C.Sc.,' F.L.S.

334 pages. 115 illustrations. 5i-in. X Sil-in.

(.Alston Risers. Price 4 6 net.l

Botany, possibly because of its general popularity, suffers
by reason of many students restricting their attention to
morphology, and paying but little heed to the physiology of
plant life. To enable botany to take its proper place in
education it must be regarded as a branch of biological
science and the struggle between the plant and its environment
must be studied.

Messrs. Bevis and Jeffery have produced a book which
supplements the elementary text-book and the flora, and assists
the student to associate form with function and function with
environment. The first part deals with the fundament.al
external factors — water, temperature, light, air and soil ; then
follows a physiological section in which plants are considered
with regard to functional similarities. The final part is the
most suggestive, dealing as it does with plant associations
and the exolution and distribution of the British flora. A
careful study of this book will give the student a new point of
view and a new interest in solving the \arious problems
concerning the habitat of plants as well as the aggregation
of individuals into counnunities.

H. H. P.

NATCRE STUDY.

Methodical Xiitnre Stndy. — By W. J. Claxton. 195
pages. i(J plates. Numerous figures. 6i-in. X8viu.

(Blackie lS: Son. Price 6 -.)

( )ne of the objections which those who wallow in the
academical rut have to Nature Study is that it is not
systematised sufficiently to fall in with their ideas. The title
of the book under consideration should therefore please them
though too much method in Nature teaching would destroy
most of its advantages. In so far as the recurrence of the
seasons is followed, and continued observations on the
same material is advocated, Mr. Claxton's book is to be
connnended. The general treatment is a little too much like
botanical and zoological text books in places ; in others it is very
sketchy, and occasionally inaccurate. What does the author
mean by the mollusc's tongue being in a very rudimentary
state ? For it is a most effective instrument, as the gardener
only too well knows. We should like also to know why the
carnivorous slug Testacella should be " a great pest in a
garden which contains dahlias." No doubt teachers will get

368

Skptembkr, 1911.

KNOWLEDGE.

369

a good many suggestions from the book, which is ilhistrated
by numerous line drawings, and many familiar photographs
by Messrs. Charles Reid, Henry Irving and Douglas English.

\V. M W.
GEOLOGY.

-By J. P. JoHXSOx.
interleaved.

Price 8 6 net.)

The Mineral Indnstry of Rliodcsia-
90 pages. 1 plate. 9-in. X 6-in.

(Longmans, Green & Co.

This is an account of the present stage of development of
the Rhode.sian mining industry. Gold is. of course, the most
important mineral, and 609,950 ounces of the value of
;t'2, 568,200 were mined in
1910. A brief account of
all the principal producing
and developing mines in
1910is given, with notes on
the mode of occurrence of
the gold. It is every-
where found near the
contact of the basement
granite with the sedimen-
tary and other rocks into
which it intrudes. Whilst
gold is the mainstaj- of the
mining industry, many of
the other metals are be-
coming increasingly im-
portant, and the geology
indicates great future
possibilities for them.
Many n o n - m e t a 1 li c
minerals are also mined,
including diamonds and
coal. An excellent chap-
ter on hints to prospectors
concludes the book, which
should prove valuable
both to the men on
the spot, and those other-
wise interested in the rich

Tremadoc Beds near Criccieth.

Notice the curved strata and the marine denudation along
bedding and joint planes.

mineral industrv

of Rhodesia.

(;. \V. T.

Field Note Book of Geological Illustrations.— By Hilda

D. Sharpi:. 51 pages. 86 photographs and 2 maps.

9-in. X 6-in.. interleaved.

(Manchester : Flatters & Garnett. Price .5 - net.)

This book consists entirely of photographs intended to
illustrate the geological features seen by students during
excursions or when on holiday, and to assist them to recognise
in the field the facts which have been discussed in class.
Each photograph is accompanied by a short descriptive note,
and while most of them will doubtless be illustrative to the
student, there are a few, such as the " Wyche Cutting,
Malvern," which convey little or no geological information.
Some others have either been poor photographs or have
suffered in reproduction. The book is interleaved and is
provided with a number of blank pages at the end for notes
or for the insertion of photographs. G. \V. T.

Pebbles.— By E. J. Dunx. F.G.S. 198 pages. 76 plates.

9-in. X 6-in.

(Melbourne: G. Robertson & Co.)

The Director of the Geological Survey of \'ictoria has made
good use of the fund presented to him along with the
Murchison Medal by the Geological Society in producing this
interesting book. He discusses exhaustively the form,
material, shaping and transport of pebbles, and illustrates their
endless varieties in seventy-six beautiful plates containing two
hundred and fifty figures. Pebbles form an intermediate stage
between boulders riven by various agencies from their parent
rock, and the sand or mud to which they are ultimately
reduced. Their story, as told by Mr. Dunn, is a veritable
romance of science. The first seven plates illustrate the
history of pebbles as they pass from angular boulders, through

sub-.angular and rounded pebbles, to fine sand, in a most
graphic manner. A final chapter is devoted to the uses of
pebbles by man as tools, weapons, sinkers, w-eights and sacred
objects. G. W. T.

PHILOSOPHY.

Creative Evolution. — By Hexri Bergsox. Authorized

translation by .\rthiir Mitchell, Ph.D. 425 pages.

S!,'-in. X 5i-in.

(Macmillan & Co. Price 10- net. I

Professor Bergson's philosophy is well deserving of the very
widespread interest that it has aroused. One can say this

without necessarily agree-
ing with his views. For
what Bergson has to
advance are really new
ideas ; and if new ideas
are not always true ideas,
they are always valuable
as stimulants to thought.
In the present case, more-
over, it can hardly be
denied that there is a
large element of truth
in Bergson's arguments,
and that he puts forward
a new way of viewing the
problems of life and
philosophy, which in itself
is both valuable and
useful ; add to this a
style which almost per-
suades one against one's
will even where views
,,.,■... the most novel are
advanced. In parenthesis,
let us further add that
t'^e the work of translation
appears to have been
done in a most careful
and satisfactory manner. Professor Bergson himself having
re\ised the whole work.

Reality, so we understand Bergson, is Becoming. Concrete
time is the stuff of reality ; reality creates itself gradually,
fundamentally it is absolute duration. Life transcends
intellect, and thus it is only by the synthesis of intellect with
instinct, or intuition, the two end products of the evolution of
life in opposite directions, that a true philosophy of life is
forthcoming. Life is the outcome of an impetus given once
and for all ; it is free and thus creates as it evolves.
Materiality and intellectuality are the results of the inverse
movement to that which is life. Both radical mechanism and
radical finalism are erroneous, but the former more
emphatically so than the latter. Bergson's arguments are
splendid ; but we doubt whether he has really proved that
concrete time is fundamental reality, the creative force in
evolution ; and if time be not this, but merely a way we have
of regarding phenomena — in a word, a mode of consciousness
— Bergson's arguments against finalism will not stand. More-
over, it is difficult to conceive of life as the result of an impetus
given once and for all. Not only do we ask, whence derived r
but why given then and not at some other time ? Was this
the beginning of time, or if not, what sort of time preceded it ?
The difficulties are largely removed if one considers life as, in
its origin, transcending time, but in its manifestations
contemporary with infinite time.

The confines of a necessarily brief review do not permit of
even a satisfactory outline of Bergson's philosophy, so many
new ideas and ways of thinking does it contain ; still less, then,
do they permit of any adequate criticism of this system.
All we have attempted above is to present some of its salient
features. In conclusion, let us say that all those who desire
to keep abreast of modern thought will certainly read this
book, and will do so with interest .and enjoyment.

H. S. Redgrove.

NOTES UPON THE FUNDAMENTAL SYSTEM
OF STARS— Addendum.

Bv F. A. BELLAMY. M.A., L.K.A.S.

JrST as the second part of tlie article on "Notes
u[X)n the Fundamental System of Stars" was
passed for Press. I received from Professor
Boss, in response to mv request, some additional
information referring to certain details which brought
the subject of those notes quite to date. This
addendum will therefore serve both to include these,
and to make one or two corrections.

The letter "s" should have been used instead of
"z" for San Luis throughout the article: the final
"s" is sounded as the English "^."

The onlv meridian circle at the Dudley Observatory
is that known as, and inscribed on the cube "Olcott
Meridian Circle." It \\ as presented to the Observa-
tory by Mr. Thomas \\'. Olcott, President of the
Trustees at that time, and was made by Pistor and
Martins, Berlin, in 1856: it is eight inches in aperture
and one hundred and ten inches focal length, not
ten feet.

Since 1904 various grants ha\'e been made to the
Dudley Observatorv from the funds of the Carnegie
Institution of \\'ashington, and in the more recent
years a sum of four thousand pounds to seven
thousand pounds each year.

Previously to the connection with the Carnegie
Institution the Dudley Observatory had produced a
catalogue of about ten thousand stars, eight thousand
being between declinations — 20'' and — 37", to the
7-5 magnitude, and these observations were made in
the years from 1896-190L This work is in catalogue
form, but is not yet published.

While this work was in progress, and especialh" in
1901, after observations upon it had been completed.
Professor Boss undertook a comprehensive work
concerning all the stars visible to the naked eye from
the northern to the southern pole. The object of
this work was to ascertain, with the greatest possible
accuracy, the proper motions of each of these stars.
Also included in this were all stars, of whatever
magnitude, that had been accurately observed
previous to 1855. It was this work that the Carnegie
Institution of Washington began to aid in 1904.
The scheme, though an exceedingly e.xtensive and
laborious one, was regarded as preliminary to a larger
one that is naw in progress at the Department of
Meridian Astrometrv of the Carnegie Institution of
Washington. It may be remarked, as it is not
generally understood, that this and the Dudley
Observatory, Albany, N.Y., are essentially one.

The result of this preliminar\- work, just referred
to, has been published under the title of a Pre-
liminary General Catalogue, formed from various
sources. It contains the positions of six thousand
one hundred and eighty-eight stars reduced to the

epoch 1900, and it includes the results for the
primars- design of ct)mputing proper motions from a
collection, as complete as possible, of all accurately
observed star-positions made during the history of
Astronom\'. each authorit}- being systematically
corrected to make it liomogeneous with the mean
of all the most reliable observers.

On the arrival of the second expedition, in
Februar\-, 1909, the piers were ready, and the
instruments were carefully mounted, adjusted, and
the principal constants were investigated during the
month of March — naturally as the consequence of
very strenuous exertions.

There were usually two sets of observers for
each night. In each set there was the principal
observer at the telescope, and an assistant to
read the four microscopes for each star. One set
observed at intervals from about 4 to 7.30 p.m., then
continuously to about 11 p.m., and again for about
an hour near sunrise. The other set observed from
about midnight to 4.30 a.m. The observations were
pushed unremittingly in this manner until the end.
Additional assistants, Messrs. Mearns and Jenkins,
arrived in San Luis in September, 1909. There
were always seven observers, and for a short time
ten observers.

In the first twelve months from .\pril 6th, 1909,
nearh- sixt\' thousand complete meridian observations
were secured. For observations of this class, this
record has only been approximately approached at
Cordoba, Argentina, under the direction of the late
Dr. B. A. Gould, where in one year about fort\-
thousand meridian observations were obtained.

The meridian observations at San Luis were com-
pleted in January 1911, and the members of the
staff returned to the United States in February and
March. The)- secured in all about eighty-seven
thousand observations, upon about fifteen thousand
stars including all the stars south of declination
— 20" noted as of the seventh magnitude or brighter,
all of the Lacaille stars, and all the stars accurately
observed, previous to 1860, at the principal observa-
tories in the Southern Hemisphere. These stars
were each observed four or more times. About two
thousand standard stars were each obser\-ed from
eight to forty, or more times.

In addition to the great \vork which these eighty-
seven thousands of straightforward observations
entailed. \'ery extensive researches of immense
importance to accurate fundamental meridian work
were carried out to determine the general and daily
constants of the instrument, in order to facilitate
the reduction of the star-observations in an accurate
and sx'stenuitic foriu. These reductions are now in

370

Septemukk, l')n.

KNOWLEDGE.

371

progress at Albany with a large force of computers,
so that astronomers will not have to wait many
N'ears, as is usual with most meridian work, before
the catalogue is published : Professor Boss believes
in expeditious work.

In the summer of the present year it is anticiiiated
that the Olcott meridian circle will be again installed
and ready for work at the Dudley Observatory.
.\lban\-. The standard stars will be again observed
as already described, and, later on. the observation
of all the stars down to the seventh magnitude that
are north of —20" will be undertaken.

I will conclude these "Notes," by a quotation from
a letter from Professor Boss to me: — "The last obser-
vation \\as taken (at San Luis) on Jan. 30, 191L
This work has been accomplished at a rate far beyond
m\- anticipations. The great prevalence of clear
nights — two hundred and eighty per aiiniiin — the
large force of observers — seven to ten, and the resist-
less zeal of the staff are responsible for this." As an
old meridian-circle observer it is pleasant to read this
appreciation of the observer's work, which, somehow,
has usuallv escaped inclusion in the introductions to
observatory star catalogues.

THE A.STROXOMY SFXTION AT THE CORONATION EXHIBITION.

The admirable principle of dexoting a section of a large
exhibition to Science, which was first instituted at the Franco-
British Exhibition at the White City, in 1908, and repeated at
the Japan-British Exhibition last year, has received increased
development at the Coronation Exhibition this year. Much
might be said of the exhibits in the several branches of Science
there shown, but our present remarks must be confined to
those in the section devoted to .Astronomy.

These exhibits are deserving of more than a passing notice,
as they embrace some of the most recent results in astro-
nomical research. They consist generally of a collection of old
astronomical instruments, models, and photographs of celestial
phenomena.

Many of the instruments have been exhibited at previous
exhibitions — notably the very fine and varied collection of
Astrolabes, Quadrants, Nocturnals and Dials shown by Mr.
Lewis Evans. Seeing that such were the only instruments
possessed by astronomers for many centuries for determining
the positions of the heavenly bodies and for giving the time, it
is interesting to examine the differences in construction and
estimate the very limited accuracy that was possible with such
instruments. Mr. Evans shows Oriental and European
Astrolabes dating from the fourteenth to the seventeenth
centuries, and a large collection of Sun Dials and Quadrants
of the sixteenth and seventeenth centuries. In this connection
there is a very interesting exhibit from Gonville and Cains
College, Cambridge, of an astrolabe presented to the College
by John Cains, one of its founders — the case of which is richly
embossed and of peculiar beauty. Four examples are exhibited
of the Davis Quadrant or Back Staff, one of which is shown
by Mr. Lewis of the Royal Observatory, Greenwich, who has
contributed a very interesting account, with a drawing, of the
method of using it. From this we learn that the Back Staft'
was invented by Captain John Davis, in the year 1590, previous
to his sailing for the South Seas. Before that time the only
means of measuring the altitude of the sun was with a simple
quadrant, such as the very fine specimen by Magini, shown at
the Exhibition. The arc of the Davis quadrant was divided
into degrees, and had in addition a Gunter's scale for sub-
divisions. A Vernier was not applied till about 1518. Some
fifteen years later Elton, the clockmaker, added an index arm
on which he placed a level which made the observer indepen-
dent of the horizon. A further improvement was made sixty
years later by Flamsteed. who added a lens to the instrument,
and thus it was used until Hadley invented his (juadrant in 1 730.

Perhaps the most interesting exhibits in the Astronomy
Section are those contributed by the Royal Observatory,
Greenwich, which embrace two models of remarkable interest.
The first is a model of the orbit of Jupiter's Eighth Satellite,
showing the path of the satellite round Jupiter from the time
of its discovery in 1908 to the year 1916, predicted from
observations made in 1908 and 1909, by a method devised by
Dr. Cowell, the necessary calculations being made by Dr.
Crominelin. It is doubtful whether an astronomical model so
instructive as this has ever been constructed. The path of the
satellite is indicated by wires supported by pillars at every

three hours of Joxicentric Right ."Ascension. The path of the
satellite from 1909 to 1910 is shown by a different coloured
wire for each year. It will be remembered that the motion of the
satellite is retrograde — the mean sidereal period of revolution
is nearly two years — the mean distance is fourteen millions of
miles and the mean eccentricity 0-38. The result of this
great eccentricity is that the distance of the satellite from
Jupiter varies from eiglit to twenty-one million miles, and the
Greenwich description of the model states that it is possible
for the eighth satellite to be nearer to its primary than the
seventh. The model gives also the orbits of satellites thus VI.
and VII. and the five inner satellites to scale in their proper
phase. The scale of the model is eighty inches = one solar
unit, or one inch = one million and one hundred and sixty
thousand miles.

The second model referred to is that of a star cluster in
Taurus which has been shown by Professor Boss to form a
connected group of stars moving through space in the same
direction and with a common velocity. The exceptional
interest that attaches to this model warrants us in appending
the description of it given by the Royal Observatory.
" This model represents a cluster of bright stars which is com-
paratively near the earth. The group covers an area in the
sky fifteen by fifteen degrees, and is situated in the region of
the Constellation Taurus. From a study of their Proper
Motions, Professor Boss has shown that they form a connected
cluster of stars, moving with a common \elocity and in
par.allel directions. The present position of the Sun, with
regard to the cluster, is shown by the large white ball placed
at the end of the arm projecting in front of the model, the
plane of the base board being that of the Earth's Equator.
The wire along which the white ball runs represents the path
traversed by the Sun (or the parallel to that traversed by the
cluster ; for we may consider the Sun to be mo\ing past the
cluster, or the cluster past the Sun). The small column to the
left of the model indicates the position of the Sun eight
hundred thousand years ago. At the present time the dis-
tance of the Sun from the centre of the cluster is eight
hundred billion miles, or (say) eight million times the
distance of the Earth from the Sun. Relatively to the
Sun the cluster is moving at a velocity of twenty-eight and a
half miles per second, a velocity which will carry a star eight and
a-half times the distance of the Earth from the Sun in a year.
The distances of the stars in the cluster from their nearest
neighbours are much the same as the distance of the Sun from
its nearest neighbours, and all the stars in the cluster would
be included in a sphere of one hundred and thirty billion
miles radius. At present the stars are of magnitudes from
three and a half to six and a half; after sixty-five million years
the group will appear as a globular cluster about twenty
minutes of arc in diameter, consisting of stars from ninth to
twelfth magnitude. Of these forty-one stars, fourteen are
white stars, whose spectra are like that of Sirius : the spectrum
of the others show them to be in a somewhat more ad\anced
stage, but only a few of them have reached the stage at which
the Sun now is. They appear to be stars of great

372

K^•o^^'LED^IE.

September, 1911.

kiniinosity : three of them would be more than one hundred
times as bright as the Sun at its distance ; six between fifty
and one hundred times as bright : twenty-two between ten
and fifty times ; and the faintest of the forty-one stars has
five times the luminosity of the Sun. Out of the fourteen
stars in a group, which have been examined with the spectro-
scope, eight have proved to be binaries. It is probable that
quite a number ififty) of fainter stars also belong to the
cluster : but their Proper Motions are not as yet sufficiently
well determined to be certain."

It is not too much to say that considering the care and
exactitude with which they have been constructed these two
models are unique.

There are exhibited in the .Astronomy Section a large
collection of photographs and transparencies contributed by
the Observatories of Greenwich. Cambridge. Stonyhurst and
the Cape, the Royal .Astronomical Society and others.
.Among the most interesting is a very beautiful series of
transparencies contributed by M. Deslandres, from the
Meudon Observatory. These comprise some thirty spectro-
heliograms of the Sun in calcium and hydrogen light, showing
the most recent and remarkable results obtained at that
Observatory.

To understand the great advance that has been made in this
branch of solar research in the last few years, it should be
borne in mind that up to the year 1908, spectroheliograms of
the Sun's surface were obtained with instruments of such
moderate dispersion that the radiations from several layers in
the solar atmosphere were integrated. As the lower layers
are the more brilliant, the forms of the upper regions were
more or less masked. The construction of a more powerful
instrument at Meudon, has enabled M. Deslandres to satis-
factorily isolate the light of the upper atmosphere from
that of the lower strata. The results can be very well
studied in the photographs exhibited. Numerous examples
are shown taken in pure KJ light — the highest layer

in the Sun's atmosphere yet examined. These are new. and
the credit of obtaining them belongs to M. Deslandres. Com-
paring these with those taken in K2-3 light it is found they
possess characteristics which distinguish them clearly from the
lower layers. Striking examples are shown of the curious
black markings called "filaments." and the connection of these
filaments with S(jlar prominences. Equally striking is the fact
noted by M. Deslandres, that some of these filaments seem to
form a zone round the poles. The photographs taken in
hydrogen light are eijually worthy of study. They show
remarkable difl'erences, according as the}' are taken with the
centre or the borders of the Ha line.

Interesting photographs are exhibited taken uith the
'■ Spectroenregistreur des vitesses," that is, a spectro-helio-
graph of Velocities, which photographs the displacements of
the spectrum lines in the line of sight for all points on the
solar disc. The study of the results obtained with this new
method of M. Deslandres shows that vapours are rising over
the areas represented by the dark filaments, and descending
over the areas represented by the bright faculae. Space does
not allow of our giving a more detailed account of this exhibit
which is deserving of close study.

The late M. Charles Emile Stuyvaert, of the Royal Observa-
tory, Brussels, devoted the last ten years of his life to the
construction, in wax, of a model of the moon which was
almost completed at the time of his death in 1908. The model
was made on a scale of one-millionth the natural size. One
portion of it representing the Lunar craters Arzachel and
Alpetragius is shown at the exhibition, and is one of a series of
twenty-four similar models which represented the complete
hemisphere.

(jn the whole, the science of .Astronomy is fairly well
represented at the Exhibition, not only in the list of those
who have sent contributions, but from the fact that the
exhiliits may be considered in many respects as indicating
the most recent adv.inces in the science.

NUTICKS.

NOTES OF A NATURALIST IN THE MEDITER-
RANE.AN. — Mr. G. B. Hony asks us to point out that the
date which was given in .the August number for the
appearance of Nightingales at Granada as March 10th should
be May 10th.

A UNIgCE SUNDIAL.~Mr. J. A. Hardcastle writes to
say that at his request Colonel \V. (i. .Armstrong some time
ago described a similar sundial to that of which Mr. A. Paul
Monckton gave an account in the August number, in The
Journal of the British Astronomical Association, and
that Miss .Agues Fry has pointed out that there is one
depicted in Holbein's picture of "The Ambassadors" in the
National Gallery.

APPARATUS FOR ELECTRO - THERAPY AND
DIAGNOSIS. — Messrs. W. Watson and Sons' new catalogue
dealing with these subjects runs into nearly one hundred pages.
Besides containing illustrations of all the most up-to-date coils
and X-Ray tubes, screens and radiometers, it shows some
interesting pictures of an improved intensifier screen called
the '" Sunic " for X-Ray work, by which the exposures are
reduced by ninety-five per cent. The saving in the life of the
tubes quickly repays the cost of the screen. The figure
showing sciagraphs of a hand taken with an exposure of one
twentieth of a second on a plate of which half only was
covered with the screen, is very remarkable.

THE FEKY REFRACTOMETER.— We h.ise pleasure
in announcing that Messrs. Adam Hilger, Limited, have intro-
duced M. Fery's Refractometer and have issued a descriptive
pamphlet with regard to this instrument which is a direct read-
ing refractometer for taking the refractive index, for sodium
light, of oils, solutions of acids, sugar solutions, mixtures of
glycerine, alcohols and so on with water.

AN IMPROVEMENT IN THE MICROSCOPE STAND.
— Messrs. R. .S;. J. Beck have introduced an improvement in
the shape of the stands of many of their microscopes which
allows the limb of the microscope between the fine adjustment
screw and the stage, to be grasped by the whole hand so that
when the instrument is lifted none of the adjustments are
altered. The same firm has put upon the market a grinding
and polishing machine of a most compact nature for the pur-
pose of making microscopical specimens for metallurgical
work.

PRISM BINOCULARS.— Mr. E. Leitz sends usan illustrated
list of his prismatic binoculars, which includes several new
patterns. At one end of the series is an instrument giving
a magnification of four diameters, which is used in the theatre
while at the other end is a field-glass giving three times this
magnification. There is a new glass also with a magnification
of eight, which has an enlarged field of view and an improved
stereoscopic effect. The latter is obtained by increasing the
distance between the object glasses relatively to that between
the eye pieces, and this, particularly at the range at which a
student of natural history would require to use the glass,
certainly assists vision.

MICROSCOPES AND ACCESSORIklS.— Section one.
Part one, of Mr. C. Baker's catalogue deals with the microscopes
made by his well-known firm. Among special microscopes
are the inexpensive ones designed for nature students and
meat inspectors, while we may also mention the diagnostic
microscope for the use of officers in foreign medical service
for the diagnosis of malarial fever. .A very similar model has
also been designed for the use of travellers.

Parts two, three and four of the same catalogue are occupied
by dissecting instruments, stains, mounted specimens for sale
or hire and apparatus for collecting pond life.

Knowledge.

With which is incorporated Hardwiclce's Science Gossip, and the Ilhistrated Scientific News.

A Monthly Record of Science.

Conducted b\- W'llficd Mark Webb, F.L.S., and E. S. Grew, M.A.

UCTULJKR, 1911.

THE METEOROLOGY OF THE UPPER AIR.*

By J. EDMLND CLARK. 11. A., B.Sc, F.G.S., F.R.Met.Suc.
[Bciii^ the Prcsidciitujl Address, 1911. to the Croydon Xatural History ctnd Scientific Society.]

\\'HEN last year I addressed m_\- felldw nu-nibers.
who have honoured me by placing me in the chair,
which I am now vacating for one' who has long
given us able service, reference was made to the
three chief forward strides made in the realm of
Science during the opening decade of this twentieth
century. These are familiar to us as Mendelism.
Radiolog}- (if that word may be applied to express
the idea briefly), and the exploration of the Upper
Air. The first of these was then enlarged upon :
the second does not, perhaps, come so entirely into
the purview of our usual acti\'ities : and it is the
more appropriate that, as a worker in our second
section of Meteorology, I should turn to the subject
of the Upper Air. just as a consideration of
Mendelism linked itselt with our hrst Section — the
Botanical. This subject, moreover, claims an added
interest in view of the remarkable progress made
in the last two years in practical flight by man.

Although few definite generalised results had
been reached previous to the present century for
heights much exceeding one mile (two kilometres),
pioneer work of no small value dates back to the
early sixties. For moderate heights the first begin-
ning was made one hundred and fift\' vears before.
The astronomer. Professor Alexander Wilson, of

Glasgow, and one of his students, in 174'), attached
thermometers to kites strung in series. This was
three years earlier than Franklin's classic experi-
lueiit. by which he pro\ed that lightning was an
electric discharge.

From that day on, kites ha\e been one of the chief
methods for the investigation of the free air in its
lower parts, second in importance onl\- to the results
in higher parts b\- balloons. Loftv mountain stations
have also afforded many valuable facts. But it is
obvious that records so obtained are vicioush-
affected in a double manner, so far as the real state
of the free air is concerned, nameh', by the
disturbing effects of the land surface, with its own
conditions of temperature and moisture, and bv the
dislocation, through the slopes, of the normal
atmospheric flow, resulting in profound modifications
of temperature and saturation.

For practical purposes onl\- one other source of
knowledge remains, that afforded b}' clouds as to
wind direction, saturation, and whether the stratum
is above or below the freezing-point. The first
scientific work through clouds began with their
classification by Luke Howard, in 1803, which, after
remaining practical!}- unaltered for nearh- a centiir\ .
has now been re-organised rather than replaced.

Autliorities. — Besides the frequent communications during the last few years to the Royal Meteorological Society, and in
Symons's Monthly Meteorological Magazine, the writer has specially consulted the \aluable summary of our ]<novvledge
presented by Messrs. Gold and Harwood to the Winnipeg Meeting of the British .Association in 1909; Sir John Moore's
" Meteorology, Practical and Applied" (1910) ; Meteorological Office Publication No. 202 (Perturbations of the Stratosphere) ;
"Das Werter": and Mr. William Marriott's account of James Glaisher's Meteorological Work (19041. There is a
very informing article by Professor .\. Lawrence Rotch, the able director of the Blue Hill Observatory, near Boston, U.S.A.,

in Tlie Scientific .American of October 22nd. 1910.

I William Whitaker, F.R.S., F.G.S.

373

374

KXOWLMDGK.

OcTdr.EU. Uni.

The imjiortant work carried out through balloons
is of the more interest to ourselves, since for thirt\'
years the originator of scientific upper air explora-
tion In- this means. John Glaisher, lived in our
midst. True, a small beginning had alread}" been
made in 1852 b\ Mr. Welsh, of the Kew Observatory.
In 185iS, the British .\ssociation appointed a com-
mittee to investigate decrease of tem[)erature with
altitude, but it practicalK' did nothing. A new
committee, appointed in 1.S61. included Admiral
Fitzrox'. Airv, Brewster. Herschel, Tyndall and
Glaisher. After disheartening failures the generositx'
of ("oxwell came to its rescue by offering to build a
balloon for their use. Mr. Glaisher responded to
this enthusiasm hv determining himself to make
the observations. Thus began in 1iS(j2 the famous
ascents b\" which for the first time ai)pr(>ximatel\'
correct data were obtained for what we may call the
middle region of the atmosphere at present accessible
for meteorological records. In the course of three
vears a height of eleven thousand feet, or over two
miles, was exceeded on no less than eleven
occasions, including that most famous ascent from
Wolverhampton, on September 5th, 1862, to the
unprecedented height of about seven miles, when Mr.
Glaisher became unconscious and Coxwell, with
hands frozen, barel\- succeeded in pulling the valve
cord w ith his teeth. This height has probably ne\er
been surpassed b\' an\ balloonist of later \ears.
But no observations were taken above about thirty-
one thousand feet, whereas, in 1901, Berson in
Germany took records to nearly thirty-fix e thousand
five hundred feet. In this case both nun became
iniconscious, onl\- reviving when the\' had fallen
two-and-a-half miles. In 1875, two out of three
French meteorologists were suffocated at a height
considerably less.

These disconcerting consequences indicated only
too plainlv that direct observation b\' manned
balloons was only possible ui) to six, or, at most,
seven miles, and that but rarely, at immense cost.
This has led to the present development of free
balloons, or bullous sondes, a method alreadv
suggested hx Le \"errier in 1874. It had. indeed,
been (juickly acted upon, but onh' in the form of
pilot balloons, to determine wind direction and height
of clouds, and by these, from 1877 onwards, much
valuable knowledge was secured.

While balloon work was thusde\eloping, ad\ances
of eijual importance were made by means of kites.
In 18.SJ, E. D. Archibald first used piano-wire in
experiments on wind velocitw His liiram's anemo-
meter was. perhaps, the first recording instrument
employed in Upper Air research, but it only ga\e
the total from beginning to end. Two years later
began the splendid series of observations which has
made the Blue Hill, in Massachusetts, a household

word wherever meteorologx' is f(_)llowed : and here
it was. in 1890, that William A. Eddy devised a
iorxw of tailless Malaw or — as we used to call them
at school — Dutch kite, which now, as the l)o\-kite.
has superseded all others. .\t Blue Hill again, four
years later, was sent up the first continuoush'
recording instrument, and from this date progress
was rapid and wide-spreading, for, in 1898, th?
ni_'\\ K-founded International Aeronautical ("oni-
niittee was alread\' recommending similar work
U)v all stations of the first class, advice which was
adopted in France and Russia. Work in England
was initiated bv Mr. W. H. Dines, especially with
flights from tug and shore on the west coast of
Scotland in 1902, work since continued for the
Meteorological Office, in association with Inilloiis
soiulcs, first at Oxshott, since at Pyrtoii Hill, in
Oxfordshire. To him, perhaps, more than to an\-
other person, Englanil is indebted for her present
good position in this new field f)f eX[)loration.
The famous French sa\ant. howe\er, M, Teisserenc
de Bort, first achieved a height of over a mile, by a
kite flown from a Danish gunboat in the l:5altic, a
height which now has in some instances been nearly
trclilcd. It was not long before our ISritish Office
added Upper Air records to its weckK' weathe '
reports, as thev were taken at Glossop, Pyrton Hill,
Ditcham Park and Brighton. At the lirst station,
under the supervision of Manchester Uni\ersity. daily
records are made, as far as jiossible supplemented
by balloons when the wind is deficient.

I>ut kites are, of course, strictlv limited in height
of ascent, and it is with pilot balloons and ballon
sondes* that the recent extraordinar\- success in
obtaining extensive series of records at heights up to
and abo\e ten miles have been secured. Thirteen
to fourteen miles is perhaps the present thoroughly
ascertained limit.'' These ascents are made b\'
means of rubber balloons, usualh' weighing half a
pound and about half a metre across, filled with
hydrogen and used either singly (sometimes with a
parachute), or else in pairs. They are filled sufficiently
to burst at a given elevation (one only in the case of
a [)air, when the other acts as a parachute for the
combination) and carr\- special recording apparatus,
carefulh' guarded against rough shocks \\hen
striking ground again. The heights, when possible,
are determined bv one or more theodolites to check
the aneroidogram record, on which alone, more
frequentlw the observations have to depend.

Besides more sporadic work concerted observations
have, since 1901, been made on the first Tuesdax' of
each month b\- nearh' all Euro()ean countries. To
the instruments is attached a ticket w ith instructions
to the finder and the offer of a reward for its return.
As a rule more than half those sent up are so recovered,
sometimes after a flight of owv two hundred miles.

'■' A pilot balloon gives wind directions at \ar\in,i; lieights by theodolite observations ; the name, " sounding balloon " is

applied inoir iisnall\' to ballonets with recording instruments.

I Some English records ha\'e been obtained almost certainly for at least fifteen miles; but the values above twelve miles

are subject to serious possibilities of altitude error.

OCTOBliR. 1911.

KNOWLEDGE.

375

heights

Ha\ing thus indicated
the manner in which
instruments ha\'e been and
are carried to various
IS, a few details
concerning them will he
ap[)ropriate before discus-
sing tht results obtained.

Glaisher. in Coxwell's
"Mammoth."" devoted him-
self mainh- to the relation
of height with temperature,
and with h\-grometric con-
ditions, while not overlook-
ing possible chemical and
magnetic changes, cloud
forms, changes of air cur-
rents, and so on. His out-
fit included a mcrcur\'
barometer, aneroid, drv and
wet bulb and maximum and
mini m u m thermometers.
Daniells and Regnaults
hygrometers, horizontal
magnet, electrometer and
sealed exhausted tubes.
This appalling array for a
single obser\er \\as set out
upon a hoard, readv in
case of danger to be in-
stantly packed for safety.
Coxwell acted as time-
keeper as well as pilot.
Each high ascent cost £^50.
so that the number avail-
able from the British
.Association grants was
limited.

In recent \'ears. of course,
self-recording instruments
have done the work, those
intended for kites being
the more solid in form.
Yet even the complete set
now usualK' attached to
these Weighs onl\- one-and-
a-half to two-and-a-half
pounds, including a clock
with recording drum, a
large double .\neroid or
Bourdon tube barometer.
Bourdon tube thermome-
ter,* Robinson anemome-
ter, and hair h\grometer.
This and the thermometer
are cased in a polished
aluminium ventilation tube.
having a vane to keep it
end on to the wind. This
is most essential to ensure

liy ://.

Temperatures and Pressures in a block of Atmosphere

fifteen miles thick, over a portion of the British Isles,

July 27th and 29th. 1908.

Bourdon tubes are circular arcs, tlic

Uibe exhausted for barometer, and filled with
Varying pressure alters the curve.

true temperature and
humidity records. Un-
fortunately, Glaisher"s re-
sults were to some extent
vitiated from ignorance in
his time of the necessity
for this. In England, now,
the much lighter apparatus
designed by Mr. Dines is
used ; essentially a card-
board disc, revolved b\'
clockwork. On one side
of its upper face is recorded
pressure and huinidit\ :
on the other temperature
and wind speed.

Eor ballons sondes still
lighter apparatus is re-
quired. Out of England
the usual instruments
weigh about one-and-a-
quarter pounds. The Ger-
man form, perfected In-
.Assman, consists of an
endless sheet between two
drums. One of these is
turned by aneroid changes.
Two pens pressed against
the sheet are mo\'ed at
right angles to this motion
by changes of temperature
and humidit\' respectiveh',
being attached to the neces-
sary instruments. Time
may also, however, be
recorded b\- a small clock,
though this is not essential,
and the whole is encased.

In England, again, the
far lighter Dines" instru-
ment prevails, weighing
either t h r ee - a n d - a - h a 1 f
ounces or one ounce.
This, however. discards
luiiniditv records. The
aneroid is attached b\- one
face to the frame, by the
other. indirectK-, to a
parallel rod of invar, a
lever from which moves a
st\ lus across the face of
a silvered metallic strip,
which is attached to the
frame. The invar rod is
itself part of the metallic
thermometer, so that at
constant temperature its
st}-le makes a parallel
scratch, which, however,
diverges with a fall of

a suitable liquid for thermometer

376

KNOWLEDGE.

October, 1911.

temperature. The scale is such that one-tenth
inch equals lOOC. sd that TC. or -001 inch can
easily be read with a low power microscope. A
thin strip of German silver is used with the rod

^Investi^aUon cf the Upper ft ir /SOTS

D-rj^ar^ Park A
Til! c'rx't^ '■OKjr-c/ rt-t sarcrtr/ afa^iofK '^'tACf** a

Corr-tiponcl.ng dafti art •nrf>coft^ bj '*'l iarr-m

€^

As to accuracy Dines is correct for temperature
within 0-8-C against IT by the Continental records,
hut the height records are less reliable, the a\erage
pressure error being eight millimetres or one-fifth

inch, against fi\-e millimetres, or

rather under (Hie-sixth inch.
Although at three miles these
errors are only about one hundred
and fift}' yards, at nine miles the\-
increase res[)ccti\el\- to about five
hundred and fifty and four hundred
and thirt\' yards, and at twelve
miles to over one thousand one
hundred (one kilometre) and six
hundred and seventy yards.

Finally we turn to the object of
all this work and the measure of
results attained. .\s to the former
there is now added, so far as the
first two miles or so is concerned,
the additional desire of knowledge
helpful to aviation. This has
alread}' borne fruit ; for it has
been established that eddies and

uprush gusts.-

all dangers bv the fliers, -

By the iojirt^iy o/

FiGURK 5.

Uis Mnjcity's Statioficrv Ojffice.

Map of British Stations.

of invar, the latter being a non-expanding allo\-.
The two are slightly separated, and fixed at one
end. The pen lever, attached to the free ends,
multiplies the difference of expansion some tenfold. '
The whole is encased in an aluminium c\linder,
open at each e;id.

Because of this extreme lightness, English results
include a larger proportion of records up to tweKe

miles or so, which is some set off, both to the these Upper Air explorations, to which reference
omission of humidit\- records and the greater danger mav now be made,
of loss by falling into the sea. It has been, of course, long known that

-most dreaded of
-rapidly
decrease as the surface is left.

But the original incentives,
other than purel}' scientific, were
more entirely meteorological and
practical, natnely. to enable the
authorities responsible for weather
forecasts to attain a yet greater
accuracx'. So long as surface ob-
servations only were available, any
complete discussion of the causes
£5^ and modes of air movements was
/^5"\s plainly as iinpossible as it would
^^ be for a geographer thoroughh" to
survey a country without lea\ing
a railway running due north and
south. I'or just as, to him, east
and west observations are equally
as essential as north and south
for his two-dimension chart, so
also does the meteorologist require
to work in three directions for
his three-dimension chart. Already
this has been strikingly illus-
trated bv Dr. Shaw, the capable head of our
Meteorological Office, who built a most beauti-
ful and instructive model, in the form of a
triangular prism, of the atmosphere to a height of
fifteen miles above the British Isles, the angles l>ing
at Limerick, Crinan and Pyrton Hill in Oxfordshire
(see Figures 1 to 4). A casual glance reveals the chief
and least expected phenomenon brought to light by

This description follows the construction of the hghter apparatus, as used in 1910.

OCTOBKR, IQll.

KNOWLEDGE.

377

temperature decreases rapidly with height, namely,
at the rate of 1°F. for every three hundred feet.
It is now well established that, in the lower two
miles, this is frequently reversed, a fact jireviously
thought exceptional. But from this height up, as
shown by the closely-set parallel lines of the model,
there is great and constant regularit\-. Formerly, it
was supposed that this continued unbroken until the
cold of space was reached, presumably somewhere
near absolute zero, or — 273"C. No one dreamt of
an\ serious di\'ergence. When, however, the
bdlloiis sondes records began to accumulate, one
of the most obvious facts obtained was that at a
hcMght, usualh' of about si.x miles, temperature
cl'cisl'c/ t(i fall, and on the contrary tended again
to rise, and that this unlooked-for reversal, so
extraordinar\- that as yet we have for it no
certain explanation, continues as high as we
ha\e at present an^" observations, namely, at
the least up to a height of fifteen miles.

In other words, whilst
we still cannot but believe
that, outside our atmos-
phere, the cold of space
is intense beyond easy con-
ception, so far as actual
knowledge goes, it ceases
to grow colder at a height
of six miles and remains
prac t ical 1\' u nal tered
tliiDiigii, at any rate, the
succeedmg eiglit or nine
miles.

This 1 a %■ e r was first
named, verv appropriately,
the " isothermal layer,"
but. to connect it with
the regions of change
beneath, these latter have
been called the " tropo-
sphere," the upper the
" stratosjihere." The latter
lies abo\'e the highest \isible
clouds.

The average height of
the lower surface of the
stratosphere, which is. how-
ever, subject to consider-
able local perturbation,
alters both w ith the season
and latitude, being, in
Europe, least (9-1 kilo-
metres, or about tive-and-
a-half miles) in March, and
highest (11-9 kilometres or
about seven miles) in
October. The only decided
break in the curve is for
September, a kilometre
lower than August, and
one-and-a-half kilometres
below October. It is

that here also occurs, at least in the
British Isles, the chief break in the rainfall curve.
This, also, is the time when the north trade
winds are at a minimum, and there may well be
some association. The temperature is lowest in
February ( — 80°F.), highest in September ( — 60°F.).
Observations outside European latitudes are still
exceedingly rare, but some special ascents in East
Africa, over the Atlantic, and in the West Indies,
have given important evidence as to equatorial con-
ditions. Over the Atlantic the stratosphere was not
reached at fifteen kilometres, which is nearly nine
miles, or half as high again as the European average.
It was, however, revealed by two ascents made on
the Victoria Nyanza, which reached a mile and three
miles higher (ten and twelve miles). Here, in
equatorial regions, was recorded the lowest air
temperature \et obtained, 119"F. below zero
( — 84'-''C). Thus we have the interesting result
that the regular fall of temperature continues up

CURVES SHOWING CHANGE OF TEMPERATURE WITH HEIGHT ABOVE SEA- LEVEL
OBT/^NED FROM BALLON- SONDE ASCENTS 1907-8.

-40 -20 0 IQ

TEMPERATURE IN DEGREES TAHRENHEIT ,

230 Z40 2^0 ?60 270

TEMPERATURE ABSOLUTE

/Us I^Inffsty's Staiifltiery Office.

Figure 6. Relation of Temperature and Height.

300

378

KNOWLEDGE.

October. 1911.

to the base of the stratosphere, however hii^'li that

mav be.

\\ ind changes are a second most important

element in passing from the troposphere to the

stratosphere, es-
pecially as to
\elocity. \t times
this is extreme.
Thus at Ditcham.
July 2Sth, 1908, it
fell from over fortv-
hve miles an hour
to about six miles.
Three days later,
however, from over
sevent}- miles, the
drop \vas onl\- to
fifty-eight miles.
The stratosphere,
therefore, is com-
paratively a region
of calm as well as
of even tempera-
ture. This appears
to continue at least
up to fifteen miles.
r>ut at some higher
point there is a
re\erse change.
To dust from the
Krakatoa Eruption.
in 1883. was as-
>igned an initial
height of about
thirty miles. At
this height, which
is just double that

explored by recent investigations, was found over the

equator an east wind that carried the dust with a

velocit\- of some seventy to eighty miles per hour.

At a height of about hfty miles the long enduring

streak from the meteor seen on Februarv 22nd. 1908.

tra%-elled with \clocities up to and o\'er one

hundred miles an hour.

We must not forget that the assumed extent of

the Earth's atmosphere, some two hundred miles.

is at least fourfold this heit;ht. Its densitv still

A't' //;c courti'sy oj His Majesty's Stationery ( >^//<

Figure 7. Dines" Balloon
Meteorograph.

suffices to raise meteors to white heat, by friction,
up to about one hundred miles.

Observations at Potsdam indicate that, with a
mean surface velocit\- of twelve miles an hour, the
speed is seventy-five per cent, greater at a height
of five hundred feet, and a hundred per cent., or
doubled, at rather over the mile. It is trebled at
about two miles, and abo\'e three miles rises to
over fifty miles an hour. Up to fifteen hundred
feet the \'elocity almost alwa\s increases, but it
frecjuentlv falls off higher than this, especialh"
with South-east winds. The velocitv just below the
stratosphere may exceed twn hundred miles per
hour.

The interest and imj>ortance of the unexpected

Fig r RE S.

H. R. Mill, n.Sc.
Vl'me^' Box Kite.

results detailed
ing upon them
valuable discov
ence. But wh
indicate that.
Biologv. the ac
of Upper Air
decade of the
long to stand
achievements.

above must be the excuse for dwell-

at such length, so that other verv

eries must remain without refer-

at has now been said suffices to

;is in the case of Mendelism and

\ances of Meteorology in the region

exploration during the opening

twentieth century are destined

in the foremost ranks of scientific

MKTEOROLOGiCAL PHOTOGRAPHS.

The United States Weather Bureau is forming, in its hbrary at
Washington, a collection of meteorological photographs, and
will welcome additions there to from all parts of the world.
The following classes of pictures are among those desired :
1 . Views of meteorological offices, observatories and stations.
Pictures of meteorological apparatus.
Portraits of meteorologists: views of their homes and

birthplaces.
Views showing the effects of storms, inundations, freezes,

heavy snowfall and so on.
Cloud photographs.

Photographs of optical phenomena (rainbows, halos,
Brocken spectre, mirage and so on).
7. Photographs of lightning and its effects.

2.
3.

4.
6,

S. Photographs of meteorologically interesting pictures in
old books, or of early prints and paintings. 'e.g.. contempor-
ary pictures of the damage wrought bv the Great Storm of
1703, in England.)

Persons who are willing to present such pictures to the
Weather Bureau, or who will fiu'nish them in exchange for
Weather Bureau publications, are requested to address :
Chief C S. Weather Bureau.
(Library.! Washington. D. C.

It will add much to the value of these pictures if the sender
will kindly note on the back of each as much pertinent inform-
ation as practicable. On picture of classes 4-7, inclusive,
should be stated at least the date, hour, and place at which
each picture was taken, and the direction toward which the
camera was pointed.

THE NEW ASTRONOMY.

II.— DOUr. LR AND WONDER STARS.

Bv PROFESSOR .\. \V. r>ICKi:RT()X.

The Star that rules our planetary system is a their cycle, and some only a few hours. They vary
comparatively steady and commonplace luniinar)-. in all kinds of different ways, but apparently there
The Sun has its storms, but for thousands of )-ears are but few of them Init ma\- be e.xplained on the

no one knew of them. He is neither strikingly

large nor inordinantly small. Sir Da\id Gill says:

■■ Our Earth is a very insignificant [)lanet revoK'ing

round a very insignificant Sun.'" The more the

stars are studied, the more complex a ver\" large

number are found to be, and

some hundred thousand are

larger than our Sun. Scores

of thousands of them are double,

and between one and two

thousand of them are known

as Wonder-stars because the\-

exhibit fluctuations of intensit\-.

In 1596, Fabricius missed a

star that he had seen some

little time before. Then again

in a few months he was

astonished to see. it once more.

He soon found that there was

the theorv of

a rough regularit\- of

little

FlGlRE 9. Diagram showing the formation
of the orbit of a Double Star.

'rhe doited circle represents the nebula e.xpanding beyond

aphelion distance.
The two continued hyperbolas represent the path of the
two stars had there l)een no collision. The collision occur-
ring, the orbit becon.es a long ellipse, thai becomes of

less eccentricity because the nebula has e.vpanded.

The meteoric nucleus left behind by the third body will

produce a resistance at perihelion and this will tend to

make the orbits more ciicular, as shown in the diagram.

less than a vear m its waxing
and waning period. Because it
was in the Constellation of the
Whale and such an extra-
ordinary star, he called it
Mira Ceti, or the wonderful
star of the \N'hale. Although
we now know over a thousand
variable stars, this o Ceti or
the star Omicron of the Con-
stellation of the Whale, is perhaps still the most
remarkable Wonder-star of the entire hea\'ens. and
probably man\- astronomers would have to admit
that thev know as little of the cause of its re-
markable fluctuations as did its discoverer Fabricius.
Another verv remarkable variable star is named
.Algol, or the Demon star, and this has also been
known for a great many years. Mira seems to have
every kind of irregularity of variabilitv, whereas retreating stars is subject to the attraction of the
Algol is as regular as a clock, and the cause of the other torn sun, and of the new star. That is, each
variation of this star is well known. The Demon of the suns when at similar distances are subject to

an attraction of seven, whereas before the impact

principle of " partial impact "" aiui
the third body."

Lea\ing actual observation we will return to
deduction and trv to trace d}namicall\- what must
happen to the two torn suns that we have assumed
to have cut deep vallevs in one
another, and that have passed
oiu- another and are increasing
their distance in space whilst
leaving between them the e\-
l)loding star. One of the first
things we must stud\' is the
effect of the attraction of this
temporary third star upon the
two escaping suns. In the story
of Nova Persei some few of the
salient properties of this third
star were discussed. One was
that it is thermodvnamicallv un-
stable, and hence it necessarilv
explodes. Consequentlv it is
quite certain that when suns do
graze they actualh' must produce
a nova. The property we have
now to speak of is the power
of this bod\' to capture. This
property, like its thermod\namic
instability, does not seem to
be one that is easily grasped
b}' observational astronomers.
The power of the third star to capture, tends to
make the two torn suns into a pair ; that is an
orbitally connected double star. Supposing that
two equal stars have each grazed off a sixth, the new-
third body will have twice the mass lost bv either.
Each torn sun will have a mass of five-sixths of
v\hat it had before the collision, and the third star
two-sixths of one of them. Each of the two

is a double star, consisting of a dark and a luminous
body, and the \'ariation of its light is due to the
dark sun coming in front of the bright sun and
eclipsing it once in every revolution. Some of these
\ariahlu stars take more than a vear to go through

they were subject to an attraction of six. But the
third star remains at rest in space, and the two torn
suns are fl}ing from each other, so that the attraction
of the third star is eftective longer upon each of the

37'J

380

KNOWLEDGE.

October. 1911.

torn suns than they are upon one another. Conse-
quently the effective attraction is more than seven, is
realh" equivalent to about nine, that is one-and-a-
half-times as much as before the collision. If the
stars had anv proper motion before attraction
brought them together the orbit at impact would
have been a h\-perbola, generally \ery close to a
[Kirabola. After the collision the additional attraction
will in \erv manv cases convert the orbit into an
ellipse and consequently the two torn suns will
be wedded by the influence of the third body into
an orbitally connected pair, that is, into a double star
(see Figure 9). If the proper motion were large, and
the graze small, the capturing power of the third bod\-
would not suffice to wed the two stars into a binarw
The number of pairs of variable stars that are too
far se[)arated to be considered physically-connected
binaries seems to suggest that this must happen
frequentl\-. .\ list of some of these pairs of
variables tliat were found in less than a thirtieth of
the celestial vault is gi\'en on page 89 of "" The Birth
of Worlds and Systems."

It has been argued by astronomers that the orbit
of double stars that had been wedded b}' impact,
must be such as to cause the stars to collide again at
everv periastrum. This, probably, as a rule, is not
the case, but occasionalh such recurrent impacts
apjiarentlv take place. Agencies, howex'er. come into
pla\' that tend to [irevent recurrent ini[)acts: these
agencies are fullv discussed in " The Birth of
W'orlds and Systems." We will give one \'er\-
efficient agent that tends to prevent recurrent impact.
The pair of torn suns are wedded b\- the attraction
of the third bod\-, but this third body is largely
dissipated before the two stars reach their greatest
distance. Hence it is not there to attract them back
again. Consequently they do not ap[)roach so near
one another at periastrum as they would have done
had the third star remained the same mass that it
possessed when first formed. The several factors
fullv account for the low eccentricitv of manv
binaries. There is great reason to imagine that
both No\a Persei and Mr. Espin's star are cases of
recurrent imjiact. In the case of Nova Persei a
peculiar concentric-looking nebula existed before the
impact took place that produced Nova Persei itself.
As exactl}' such a nebula might have been produced
by a previous impact, this idea of recurrent impacts
seems to furnish a sufficient explanation of its exist-
ence. The accomjianying Figure 10 is one of those
taken as the nebula was progressively lit up b\- the
flash of light that was produced b\- the exploding
third star — the flash we saw and named Nova
Persei. We have every reason to suppose that
this was the case, because, as the light was pro-
gressively reflected from the whorls of the nebula,
it showed the characteristic blaze band spectrum
that was so unique a peculiarit\' of the flash period
of Nova Persei.

The reason why we may think of Nova Lacertae as
being the third body produced b\' a recurrent impact,
is that one of the two stars that came into impact in

this case appeared to have been a variable star before
the partial imjxict occurred that produced this
apparition. It may be worth\- of note that one of
the dynamical deductions as to the properties of the
third bod\- is that it passes through the stage of
being a planetarv nebula. Nova Lacertae is now said
to have become a [)lanetarv nebula.

I cannot enter into greater detail here because the
" theory of [lartial impact, and the third body " is
so wide as to reall}- constitute a new cosmogony. I
would refer students to the original papers in the
transactions of the New Zealand Institute, for the
years 1878, 1879 and 1880. These are in all the
important libraries of London.

If double stars are produced by the grazing impact
of suns, in their earl}' days the\' must have exhibited
the scars produced by the encounter and sometimes
be doubly variable : but there are many reasons why
this scarred condition should last very much longer
in some stars than in others. Consequently we should
expect to find a comparatively large number of double
stars that exhibit variability and a few that show-
double variabilit}'. There are several double stars
actually known to be thus doubly variable, quite a
large number of double stars that are single variables,
and still more double stars that are coloured, a state
which has been deduced as being a final condition of
\ariability before the torn suns have healed com-
pletely and once more become normal stars.

It would be an extremely important piece of work
were some of our amateur astronomers to find the
many \-ariable stars that are double, and especially
the man}' spectroscopic binaries that are variable and
in which the variability is not due to eclipse. Mr.
Espin and Mr. \'ictor Anestin. have already found
some most valuable and remarkable results in con-
nection with double stars, their association with the
various classes of variable stars and with density of
star distribution.

Let us now examine in some detail the condition
of these torn suns with respect to the distribution oi
the material, and the character of the motions
developed in the suns that have come into grazing
impact.

Nearh- the whole of the dynamical conclusions
regarding the grazing impact of suns were worked
out over thirty years ago, and the\' have been
subjected to endless debate and calculation on the
part of mathematicians and astronomers. If we
grant the fact that collisions must occur, as on the
grounds of the doctrine of probabilit}' seems
inevitable, we have an actual explanation of the
phenomena of temporar\-, variable and double stars,
for we cannot doubt the accuracy of the thermo-
dx'uamic deductions that are here presented.

\\'hen these basic deductions are combined with
the fact that there appears to be scarcely a single
one of all these complex deductions but has been
confirmed hv obserx-ations. we must admit that
impact, if not of the supreme importance that is
suggested b\- these researches and observations,
must be a stujiendousl}- large factor in cosmic

October. 1911.

KNOWLEDGE.

381

evolution and worthy of the most careful and
detailed study on the part of astronomers.

The diagram. Figure 11, page 382, taken from
"The Birth of Worlds and S}stems " was drawn to
show the distribution of material at the moment
when the three bodies are parting company. Assum-
ing the similar suns to be of average dimensions,
we can imagine the valleys which have been cut
along the equators of the two torn suns to be
perhaps something like a million miles in length.
The valle\- commences with a mere scraping away of
the atmosphere ; it
then becomes
deeper and deeper,
until it reaches far
down into the sun.
The material is
dragged forward,
and at the moment
of parting with the
new third star, it
is heaped up into
a huge mountain
of fire, hundreds
of thousands of
miles high. This
material being car-
ried hv momentum
in the direction
in which it has
been dragged, tends
to foil o w t h e
third star, and so
produces rotation
in the general
plane of the orbits
of the two stars. In all probability before the
impact occurred the star had a rotation of its own,
and hence, immediatelv after the impact, a tumult
of conflicting motions of the most extraordinary
character must ensue. There is first this struggle of
the two rotations, the original and the impressed
rotations, that must result in a most extraordinarily
irregular rh\thm. Then, again, we have gravitation
exerting itself, struggling to make the highly-distorted
body into a sphere. We have to remember that not
merely is there the enormous disturbance in the form
of the torn sun due to the impact itself, but there is
the disturbance due to tidal action, and although it
is possible that Chamberlain and Moulton greatly
exaggerated this action, still tidal deformation must
be of a stupendous character. Hence we have
gravity struggling to make this ill-formed mass into
a sphere. A tremendous inertia of motion will be
set up whose momentum must carry the material
past the position of equilibrium, and thus another
amazingly irregular tidal action must be at work in
each of the two torn suns.

This heated mountainous mass must produce con-
vection currents of ordinary gas and volatilized metals,
and when this is projected, as it must be, in many
cases, for hundreds of thousands of miles above the

surface of the star, in certain positions this must
produce bright line spectra. Especially will such
spectra be crossed by the bright line of hydrogen,
and this deduction has been conclusiveh' borne out.
In fact, not merely are these stars known to be thus
characterised, but hundreds of them have actually
been discovered by especial search directed to the

finding of such bright lines.

Amongst the variables

Fir.rRi: 10. The Nebula about N'ov
Observatorv bv G. W. Ric

SO discovered, some have proved to be doubly
variable double stars : that is to say. double
stars that have been so recently wedded by

attraction of the
third bod\- that
t he\' may be actually
considered to be on
their honeymoon.

It will easily be
perceived that all
the struggles of
motion and the
changes in the
margins of these
vast volcanoes must
alter in the most
extraordinary de-
gree the intensity
of luminosit\' at the
period of maximum.
It must even alter
to some extent the
time of the appar-
ent maximum itself.
It might be
thought that this
complex series of
motions, as well as
conduction and convection, would rapidly bring
about a condition of equilibrium : hence that this
inequality of heat of the rotating star would not
last long.

A detailed stud\" into all the conditions that
presented themselves was made in 1879, and it was
shown that a great number of the agencies tending
to equalit\" balanced one another and became
ineffective. Hence it appeared at that time — and
the opinion has not altered since — that approximate
equality would not be attained for many hundreds,
or in some cases thousands, of years. One of these
factors, convection, may be due to lightness, pro-
duced either bv high temperatures or by low atomic
weight, and a study of these two characteristics
will show at once that the two are tending to
counteract one another.

^^'e have already referred to the fact that atom
sorting, or molecular escape, will tend to leave
behind, in the third body, a rotating swarm of
nebulous meteoric dust. In most cases, a good deal
of this may be associated with the torn suns, and
the torn suns would also, by the extraordinary
violence of the volcanic ejection, tend to produce
vast atmospheres. It is clear these atmospheres
must tend greatly to alter the character of the

a Persei. photographed at the Verkes
hey. September 20th. 1910.

382

KNOWLEDGE.

October. 1911.

luminositv produced. One point is obvious, the
variable star is sending its vast revolving searchlight
through the whole circumference of the heavens.
\Mien it is shining away from us it will light up all
those dust particles that are on the further side, and
illumine them as the Sun does our satellite when it is
full moon. Hence we have an obvious explanation
of the phenomenon that characterises a number of
variable stars, namely, that they present a nebulous
appearance at minimum, that is. when the star is
sending the searchlight of its \'ast volcano awa\-
from us. Such, then, are some of the characteristics
of the torn suns, \\ e
also see how amazingly
impacts must differ the one
from the other : collisions
must occur between suns
of great difference of mass,
of differences oi density,
of age and hence of
luniinositN'. and then again
we have collisions from
the mere graze of the atmosphere to almost direct
impacts. We may have impacts in which the size
of the two impacting bodies are so unequal that the
one ma\- bur\- itself in the bod\- of the other, and
produce a gigantic \'olcano. such as I ha\e imagined

I ha\e
Wnrlds and

Fig I- RE 11.

I)iai,Tani showing iiiateiiH
the preceding end of valley.

gigantic \'olcano. sue
to have originated the \ariabilit\- of Mira

grazes, of course much deeper than the mere atmos-
[iherc. Nova Persei is an example of a deeper graze
although shallow. The Pilgrim star of Tycho
Hrahe was a still deeper. Nova Persei appears once
to have struck deep enough to have wedded it into a
double star. Then we pass through grazes deep
enough to produce double stars that are capable of
being separated only by powerful telescopes. With
still deeper grazes it is dynamically certain that the
collision must result in spectroscopic binaries in
which the stars revolve around one another in
periods of onl\- a few days : of such a type is .\lgol.

and the Cepheids. The
\ana lii lit\' of se\'eral of
these a[.)pears to be due
almost entirelv to mere
eclipse, the great volcanoes
that were existing at the
time they wedded have died
down : but a surprising
numlier of these stars,
both eclipsing and otherwise,
still show the blaze of the \'olcanic scar that was
l)roduced by the tremendous blow of their encounter.
Again, we go to deeper grazes and the stars scarcelv
separate, the \'ast meteoric nucleus of the third star
remains as a huge tongue of fire ioininj; the re-

dragged to

volvini? stars

th

IS 111

T\u

I'.irth

ot

the minute
|)heiioniena

discussed
Systems."

Some .scientific nun have objected to
detail in which I have describ(_>d the
deduced as following grazing
impacts. They say that we
cannot know the exact cir-
cumstances, as every con-
ceivable variet}' may occur :
but grant that we have suns
anything like approximately
equal, and of the compact-
ness that characterises most
of them, then there are six-
teen well marked characters and basic projierties that
the third bodv must exhibit as deduced dynamical
generic principles.

Obvioush- we cannot describe a tithe of all the
endless possibilities of variation, but we will just take
one kind and imagine pairs of similar suns coming
into collisions in which the imi)acts differ from a
mere graze of atmospheres down to the almost direct
collision, similar to that which in all probability
originated our solar system.

With a very shallow graze we have an evanescent
flash of light, and the formation of a pair of variables
that will continually increase their distance from one
another, due to the original proper motion not having
been wholly destroyed by the very slight attraction
of the small third body.

The pairs of variables given on page 89 of '" Birth of
Worlds and Systems," are examples of shallow

Figure 12. Diagram" showing uhy the light in
recently torn variables rises (|nicl<ly and falls slowly.

into one immense dumbbell-shaped
mass of fire. The torn suns themselves, although
one vast fier\- mass, mav still show signs of the giant
volcanoes that are still active on the surface, but
tidal action has sto[)i)ed independent rotation, and

all changes of brillianc\'
or of character are s\n-
chronous with revolution,
because revolution and
rotation have become iso-
chronous the one with the
other. The best example
of this is Beta L\rae.

When the depth of the
graze reaches to a cut of
more than a third, unless the original proper motitin
was enormous, the capturing power of the third bod\-
becomes so very great that the three stars do not
part company, but w hirl around one another as a huge
bun-shaped mass. There is every reason to suppose
that some of the Wolf-Rayet stars have originated in
this way, and their spectrograms tell us the storv
that this is the mode of their genesis. This fusion
we call cases of " whirling coalescence."

Still deeper collisions, and suns revolving slow!'.'
are produced. It would seem h\ the low angular
velocity of our Sun that this must have been its origin.
It has been suggested in m\- various books on the
subject, that planets did not originate from the bodv
of the sun. but were step-sons and daughters that
belonged to tJiie or both of the original bodies whose
coalescence made uj) the Sun.

Professor See has called his ereat book " The

From "The Riiih cif W'cjild.^ and Sv'stcms." 1>\ kind permission of Messrs. Harper and Hrothers.

OCTOBEN. 1011.

KNOWLEDGE.

383

Capture Theory " in order to emphasize this same
fact : he has independently deduced the idea that

of a httle over seven days period. We must
assume that in so close a pair, tidal action must ha\e

Time.

Figure 13. Deduced light curve of single variable in which

the impact was of recent date, hence the liglit rises iiuickly

and falls slowly.

.^nollier varialile is probably near thi^ star, or it may be one of an orbital pair : its
spectrogram should show bright hydrogen and perhaps other bright lines during

portions of each revolution : nebulosity at minimum may be expected.
The spectral lines of planetary nebula should be looked for in all spectroscopic
binaries, all variable and Wolf-Rayet stars. The pairs of variables on page Sg,
" Rirth of Worlds and Systems," should be examined both for planetary nebulae lines
:iud for nebulosity. Midway between the pairs, the meteoric residue of the third
body should he sought for.

the planets could not have ori^dnated from the Sun.
and has most conclusively demonstrated the erroneous
nature of all the old hypotheses. Thirt\' vears a,i,'o I
showed that the surface velocity of the Sun woiikl
have to he increased some fort\- thousand times its
present amount to enable matter to separate itself
and remain indei)endent of the Inuh' of the Sun.

Since I have been in
England I have devoted
man\' months to the
study of the light curves,
the spectrograms, and
other peculiarities of vari-
able stars, and there is
not one amongst the whole
that I have studied but
seems to have originated
in some form of impact.
The extremely singular
light curves and eccentric
distribution of variables
in star clusters received
fairly satisfactory explana-
tions. The eccentric light

Time.

Time.

Figure 14. Deduced light curve of a non - eclipsing
spectroscopic binary.

Associated by impact at a comparatively recent date.

Tidal action has made the time of rotation of each sun synchronous with the period

of revolution.
The volcanoes remain active in each sun. The phases of the volcanoes being
approximately half a revolution apart, the spectrosrams should intermittently show

bright hydrogen lines.
Nebulosity shi-mld be looked for with long exposure and great light gathering

power.

made rotation isorhmnous with re\'olution. It
appears that the impact occurred a sufficiently short
time ago that the N'olcanoes of impact exist in both
the stars. .Vs the pair re\'oh'e, first one of these and
then the other comes into view, giving us the well-
known curve of the Cepheids. Perhaps the most
wonderful example of the combination of many

deductions in one pair is
the doubly \- a r i a b 1 e
nebulous double star, with
an oscillatory orbit, that
we worked out in Sydney
during the time I was
there t\\ o \ears ago. This
star, also S.S. Signi, and
a number of other peculiar
\-ariables, I have described
in detail in '" The Birth of
Worlds and Systems."

In the next article, after
a few words devoted to

Figure 15. Deduced light curve of eclipsing spectroscopic star clusters and planetary

binary produced by impact of nearly a third, hence the pair nebulae, we will discuss

has just escaped whirling coalescence. jj^g phenomena that may

curves of the Cepheids The cuts in the tom suns were so deep, and the third body consequently so l.arge. be deduCed frOm the

, . r that each star has been greatly heated and so extensively bathed in the volatilized ■ f. f \\rU,t„ NAVinlof.

received most SatlSiaCtOrV shininglluid, .as to have become a luminous sun. Much of the third star will rem.aiu lUipaCL Ul Willie INCUUlclc

, . ^ . ., ■■ partly as a tongue of fire joining the two torn suns ; partly .as a nebulous and gaseous j j.u intemenetration

explanation. Eta AqUllae .atmosphere this Umer giving bright liues. Perchance the nebulosity may occasion- dUU lUe lU lei peiieu atlOll

ic r^f.rVianc the- most ally give the star a h.azy delinition, especially with long exposure. In case the ^^ y^^^ Stellar SvStCmS
IS pel uapb Ulie IIIUM i,„p,^(.t that produced this combination be of recent date, a hump of light may

t\-i-,if~nl rvf tlipcp cfni-Q Tt indicate the volcano of impact on one or both the suns, and may show on the light sUCll

INpicai Ul llicsc SLclt^. It ,^^^^^^ Possiblv the lines of a pLanetary nebula may be detected if carefully sought ^^

is a SpeCtrOSCOI>ic binar\' for by means of an analysing spectroscope. ""

as the Magellanic

Clouds or the Galax\- itself.

jvIoTK. — Association of \'aki.\hlk St.vks with Nebuloi:s M.\tter. — It is well to understand
the thermodynamic intensit\- of the volcanic ejection of solar volcanoes. Ejections from so calm a body
as our Sun 'run into velocities of hundreds of miles a second. Compare the speed of 200 miles with
half-a-mile a second, which is the velocity of our swift projectiles. (200 X 2)'^= 160,000, that is, the energy
of a Krupp shell would be 160,000 times greater than it now is, were it moving as s\\ifth- as some solar
protuberances. This then is the order of the Kinetol of projection in the torn suns.

THE ZOOLOGICAL SIDE OF COMMERCE.

HORSE-HAIR.
Bv HUBERT H. POOLE axu WILFR1:I) MARK \Vi:Br>.

Thk part
day life is
go tliroui;!

which animal [irodurts pla\- in our ever\--
very important indeed, and many of them
1 \cry elaborate processes of preparation.

I-'llU'Ri; 1.

Sorting the horsehair over suction screens.

of hairs. Indeed, there is practicalh* no member of
the class \\hich does not ])r(3duce hair at one stage
or another of its existence. That of the horse is
especialh well developed
on the neck and tail, prov-
ing ornamental in both
instances, but in the latter
also useful for brushing
away flies, which often
are a great source of
irritation.

The horse- hair used for
commercial purposes arri\'es
m hales up to half a ton
HI weight, and a hundred
and t\\ent\- pounds in
\'alue. The chief sources
of supply are Great Britain,
Nortli and South America,
.Australia, German\-, Russia
and China. The tails are
the best, because the hairs
are hard, the manes being-
soft and therefore of in-
ferior \alue. The specially
long hairs are, of course,
suitable for particular pur-
poses, but we wdl deal

The w hole subject is attrac-
ti\e. and especially so in
the cases where there is
no p o s s i 1 ) i 1 i t \' of the
creatures most tiirecth'
concerned being ruthlessh'
exterminated.

We therefore propose
to contribute a series of
articles on commercial
;^oologv to the pages of
" Kncjwledge," and while
all will be of general in-
terest, some of them will
have a special attraction for
the specialist who deals
with the groups to which
the animals in (piestion
belong.

Mammals are at one end
of the scale, and their
most characteristic exter-
nal feature is the presence

Mixini; various kinds of hair together.
3.S4

October. 1911.

KNOWLEDGE.

385

FiGL'RK i.

Tile walk in which the horsehair for stuffing purposes is twisted into ropes

first of all with those of ordinary length, which
arc to be prepared for stuffing furniture, and no
one who has not seen the process would imagine
how elaborate this is.

The hair is first sorted over suction screens (see
Figure 1), which draw out the dust and carry it

away. Colour forms the first basis of classification,
black, white and grey hair being distinguished, and
after this the hair is divided up according to its
various lengths and its quality. That w hich is to
appear black is dyed in log-wood, washed and dried,
and then, as is shown in Figure 2, the various hairs

Figure 4.
The careful untwisting of the rope after steaming and drying.

Hand cardiii

Figure 5.
the untwisted horsehair from the ropes.

October, 1911.

KNOWLEDGE.

38fi

are mixed together on the floor so as to make
stuffings of various prices. After this the material
is passed through a series of mixing machines
or mills, which are pro\ided with exhausts for
taking out an\- dust which remains.

The hand carding i-irocess is shown in

Figure 5,

Figure 6.
Horsehair ropes hangint; up to dry.

Now comes the most curious part of thi.' process.
.\ short walk is pro\'ided something similar to that
on which hempen cords are made and here the
hair is twisted up to form
ro[)es. Each pair of work-
men is followed by a tio\-
who heats up a fresh sup[:i]\'
of material and that which
is dropped, with two sticks,
thus getting it ready for the
use of the twisters. The
ropes are again twisted
ii[ioii themselves, soaked for
two hours in water, then
baked at a temperature
of upwards of A5()" V. foi
twehe hours. The damp
heat, as may be well
imagined, destrovs all bac-
terial life that might
possibh exist in the hair,
and at the same time hxes
the curl. The ropes (see
F"igure 6) are hung up to
cool for three days. The
low ([ualities are then
untwisted and carded b\'

machiner\", though this process is liable to break
the staple (see Figure 7). The good qualities are
opened out (see Figure 4) and hand carded, the
opened twists being placed on the bt-nt pins of the
carder which give somewhat, as thev are fixed
into leather that is in turn fastened to a board.

and finished horsehair is to be seen in the background.
The finer the quality the smaller the rope and tighter
its coils. The hair from English cart horses is the
best, because it is the strongest, and tor the highest
qualities long hairs are
used. The \er\' finest
grades cost up to seven
shillings per pound whole-
sale. Black hair is usualh-
somewhat stronger than
t h e w h i t e , but U u e e n
\'ictoria. who was verv
partial to horse hair mat-
tresses, always had the best
qualit\- of white hair. .\s
it takes aliout fort}' pounds
of hair to make a full
sized mattress, it will be
seen that the cost is some-
what considerable.

One man in tlie em-

plo\' of Messrs. William

List i.\: Sons, who very

kindK ga\e facilities for

this article to be written,

can b(_)ast of o\er sixty

• . years" service, while several

can claim over forty.

The men train their sons, as a long experience is

necessar\' in nearl\- all the processes.

-Messrs. List get the longest tails from China and

Untwistii:

Figure 7.
■dini; the ropes of the lower grades of hair by machinery.

Russia. These are disinfected before thev are
handled, as a precaution, and after being dipped in a
bath of soft soap and soda, are wet hackled (see
I'igure 8) to get out all the short fnr. The sorted
hairs are dr\- carded, being piled' up on a board which
is studded with long j)ins and drawn from the two

OCTOBHR, mil.

KNOWLEDGE.

387

1-"IGL'RE 8.

W't-'t hackliiiK the Iouk hairs which are not used for stuffing purposes.

Figure 9.
Drawing out the hairs and sorting them into various lengths.

3SS

KNOWLEDGE.

October, loil.

ends between an old razor and the thumb to lengths
down to five inches (see Figure 9).

White hair which is thirty inches long and upward
is used for violin bows. This is exported largeh- to
Germany by Messrs. List. Black hair, which as we
ha\'e said before is slightly stronger, is used fur tlic
bows for double basses. Shorter hair, according to
its length, is tied in bundles and sold to brush makers
or to plume makers, for whom it is dyed \-arious
colours for ornamenting helmets and the bridles
of caxalrv horses.

.\ more extensi\'e use of the long hair is tor weaving
It into seatings in which a linen warp is used, while
the hair cloth which tailors emplo\' for stiffening
garments where elasticit\' is required is made with a
warp of cotton. The widths var\- from sixteen to
thirty-four inches, and it may be pointed out that to
produce a thirt\--fouriiichcloththe hair must be thirt\ -
eight inches long. Some of the hair is of exceptional
length, and one tail in an extreme case which passed
through Messrs. List's hands measured sevent\-two

inches. The brown hair is used for fishing lines and are used for oil and cider presses and for brewers'
was much in vogue years ago for cod fishing. One

Wigs for judges and barristers are made from
w hat is known as " dead " hair which has no glint
njion it. and is specially picked out for the purpose.

The hair from the tails of cows and oxen is also
used for one or two purposes. The ends of the tails
themselves are brought oxer attached to the skins
and always show a t\\ist. This with the \er\- rarest
of exceptions is in one direction. The cow tails are
dressed whole and undyed (as are sometimes horse
tails from South America), for export to South
Africa, where the\' are used lor personal adornment
by the natises. The latter insist on the hair being
und\'ed. and the\' plait it into bracelets and o\'er
gourds used for snuff, as well as combine it with the
wire w hich is put over sjamboks and sticks. The\-
also use it for threading beads. North American
Indians use d_\-ed hair for the same purpose, and for

weavmg into their moccasms.

The cow hair is al

so cu"aw n tor wea\in

J, mto

sieve bottoms to form strainers for cooks and
gun-powder manufacturers, while horse-hair bags

advantage of the old method was that onl\- health\-
fish were caught, while now, it stands to reason,
the trawls will bring up all that come in their
wa\-, whether the\- are in good condition or not.

straining-cloths.

I^astly, goats" hair from Ohina and Tibet, being
very soft, is used for babies' l>rushes. Hut the
making of brushes generalK- is a subject which ma\'
well be dealt with in another article.

FlGUKK 10.
Specimens ut the hair lielerc .iiid alter it has been put tluoiigli tlie vanoub processes.

SOME NOTES ON PLANT PHOTOGRAPHY.

By SOMEK\"lLLI-: HASTINGS. ^F.S.
Aiitliitr of " Sniniiicr Fluiccrs of the Hif^li Alps": " Toiulstnols iit Home."

1-lGLKE 1.
To illustrate the use of the Swing-back in I'laut Photoi;iaphy

In the following pages I want to tr\' and give the
results of a fairly extensi\e experience of the photo-
graphy of plants, both in monochrome and colour
(autochrome). This has been, for the most part, out
of doors, but I have also done some indoor or studio
work. I must, from the verv first, frankly admit
that I know ver\' little of what other workers ha\e
written on the sub-
ject, what little know-
ledge I possess being
derived almost ex-
clusi\'el\' from my
own experience and
failures, so that I can
safely say that all the
suggestions herein
contained I ha\e my-
self tried and found
to be of value.

The Camera.

Let me first of all
tell you of m\- appar-
atus. I am, at the
present time, using
a (piarter and a half-
plate camera for held work and another halt-plate
camera mounted on a special stand for the studio. B\-
a simple device, the reversing back of my quarter-plate
camera can be attached to both half-plate instruments
so that I am able to use my quarter-plate slides and
changing boxes with all three cameras. These are
very ordinar\- instruments of no special make. They
give double or triple extension and have rising fronts,
though I never use this attachment. What I do
consider of importance is a swing-back giN'ing a
large range of movement in the vertical direction.
and a side swing as well : and perhaps I had better,
first of all, tr\- and explain whv these attachments
are so valuable. I use the sw ing-back in exactl\' the
opposite wav to that in w hich it is generally used, not
for reducing distortion at the expense of focus, but
for the very reverse effect. By the help of a swing-
back, any plane surface, w hatever its inclination to
the plane of the camera, can be readily focussed.
Suppose, for example, we are photographing a plant.
sav a snowdrop, as it grows in the vertical plane,
with the camera pointing obliquely down upon it.
Such an aspect has the advantage that in it we get
the ground immediatelv behind tlie plant or surround-
ing objects as a background, whereas, with the
camera on the same level, the plant stands out
against distant objects or sky, and the sense of

proportion is lost. Morever, it is much more con-
\enient to focus in this position. Suppose then that
the camera is tilted and directed obliquely down upon
the plant with a large aperture to the lens, and
we have focussed the flowers on the screen (AB)
(see Figure 1), the lower leaves and base will be hope-
lesslv out of focus. The natural tendency under these

conditions is to thitjw
backward the swing-
back so that the
focussing screen be-
comes more vertical
(AB^). But the effect
produced will be just
the reverse from that
intended, the lower
leaves will be still
more out of focus.
What we have to do
is to throw forward
the swing -back, so
that its inclination
to the Vertical is
increased (,\B'M,
that is, to bring
the upper part of
the focussing screen nearer to the object focussed.
that is to the lower lea\es. When, however, we are
looking down on a group of plants near the ground,
when, in other words, the object to be focussed is
more in the horizontal plane, the swing-back is used
in the reverse manner and the focussing screen
becomes more vertical. Not infre(}uently also, when
a row of plants is being photographed, the most
satisfactory point of view is not directly in front but
rather to the side, and in this case the side swing,
used verv much as described above, becomes
extremely useful. By lueans of an efficient swing-
back, therefore, an\- plane surface, w hatever its
position, can be focussed. and although undoubtedly
a certain amount of distortion results, as we are
photographing plants and not architecture, this can
generally be neglected. So that, to return to the
subject under discussion, in selecting your camera
be sure and see that the swing-back has an extensive
range of mo\'ement and that there is a side swing also.

Tilting Table.

.\nother necessity for satisfactory field work is a
tilting table so arranged that the whole camera slides
hackw ard and forward upon it. As I have never been
able to purchase one of these and have always
had to ha\-e it made, I mav as well describe it in

389

390

KNOWLEDGE.

OCTOlil.R, 1911.

detail. I have never found a ball and socket top to
the stand sufficiently rigid and have al\va\-s had to
use a tilting table. It is
imjiortant that this part . __
of the apparatus shall be
firm for small degrees of
tilting as well as large,
otherwise, w hen the dark
slide is introduced, the
whole- thing slips, and
the photograph obtained
is not what was intended.
To achieve this, it is essen-
tial that the locking screw
(A, Figures 2 and 3) be
as near as possible to
attachment screw (B) when

the tilting board is closed.
The tilting table should
open to a right angle
so that the camera may
look vertically down when
photographing tiny jilants.
Another essential is that
the whole camera should
slide backward and for-
ward on the tilting board.
Suppose, for e.xample, that
we are photograjjhing a
plant, say natural size,
with the camera looking
obli(|uel\' down upon it.
and have found a suitable

view on our focussing screen, and proceed to focus.
If we do this in the ordinar\- wav, bv backward
or forward move-
ment of the lens
or focussing screen,
the scale changes
at once and we
find that the flower
has enlarged itself
to, perhai)S, twice
its natural size
before it is sharplv
in focus. If. on
the other hand.
we attempt to
o1)tain correct de-
finition by moving
the camera and
its stand back-
ward and forward
along the ground
we either find that
this is exceedingl)-
difficult owing to
the sloping bank
on which the
plant grows or to
or else that, owing
camera, the point

FlGUKlC 2.
The Half-plate Field Camera.

as we advance and recede, the object falls and
rises on the focussing screen. It is much more

con\enient to focus by
sliding the whole camera
backward and forward on
the tilting board and fixing
it by a locking screw iC.
Figures 2 and 5) before
exposure. The tilting board
on which my half-plate
field camera slides has
narrow brass strips on top
which engage with similar
brass strips screwed to
the base of the camera.
There is nothing striking
about the little pieces of
apparatus w hich I ha\'e had
made to attach to the bases
of mv two field cameras,
but as a diagram mav per-
haps be of service to some
reader. I ha\e thought
best to include one with
dimensions marked upon it.
The half- plate size is here
figured and the quarter-
plate is \"ery similar, ex-
cept that the part of the
tilting board which is
nearest to the camera is
formed of an aluminium
instead of wood,
hapjiens. the camera
instead of down, it

plate
Where, as very occasionalh'
has to be directed upward

is the easiest thing
in the world to
slide theinstrument
off the tilting base
and reverse it so
that the lens points
upward, before re-
placing it.

The Stand.

There can be no
possible doubt that
the telescopic is b\-
far the most con-
venient t\'pe of
stand for work in
the field. It is easih'
carried and adjus-
ted, and one of the"
better ty[)es with
six or se\en sec-
tions to each leg
permits of the close
ajiproximation of
rocks or other ol)structions, the camera to the ground in photographing small
to the tilted position of the plants. It is rigid enough even with a half plate
of \iew entirelv changes, for camera, and is very rarely used fulK" extended.

The tilting base on whicl

FiGiKi; 3.
the Camera slides backwards and forwards.

October. 1911.

KNOWLEDGE.

391

\Miere there has heen a strong wind blow ing I have

sometimes increased the weight, and therefore the

rigidity, of my N\hole apparatus by placing a few large

stones, wherever I could find room for them on the

camera base. And sometimes

where the camera and stand are

much tilted, a few stones piled

around that leg which has a ten-

dencv to rise will make the whole

thing much firmer. If you are

likelv to use \our camera-stand

more than once, get a brass or

steel one and strenuously avoid

those made of aluminium.

The Lr-:NS.
next to the

Turnin
of the lens I can
give you my own
perience. I have

makes but have got

questiiin
again t)nl\-
imited ex-
tried most
rid of all
mv lenses, except a Zeiss Tessar,
which I use for everything.
It is a delightful lens, and of
especial value in autochrome
work. It is certainly the best I
have tried, though it is quite
likely that there are others just as
good. The right thing to do
is clearly to tr\- the lens you
have and wait to get another
till you are quite certain that your
jjresent one is deficient. I prefer
a rather short focus lens, for
then one can photograph an
object natural size \sith the
camera somewhat less than doubly
extended, and complete double
extension gives a slight magnifi-
cation. Besides, it is often easier
to pitch one's camera quite close
to a ])lant than some little distance
awa\-, particularly in rocky places.
There is no advantage in a wide
aperture lens for plant photo-
graphy. One working at V 6-5
or F 8 is quite good enough, and
I never remember photograjihing
a plant with a larger stop than
F 8. Much more often one has to stoj) down
to I*" 24 or :>2 to obtain sufficient depth of
focus. Occasionally in the field, and not infre-
quentlv in the studio, it may be desirable to
photograph a plant or flow er larger than natural size.
This can be managed with the hel|) of a triple
extension camera, but rigidity is almost invariably
lost with the greater degrees of extension, and it is
much more convenient to increase the power of the
lens by the addition of an ordinary convex objective.
I use a simple convex lens placed in front of m\-
camera lens. It is a corrected lens, being made up
of two glasses cemented together, and is really the

objective bought w ith a cheap quarter-plate camera.
With it I am able to obtain any magnification
up to six diameters. Beautiful autochromes as well
as ordinar\' photographs can thus be obtained.

Plates.

For all ordinary work plates
are much to be preferred to
films. Backed plates should
alwa\s be used, and a colour
sensitive plate is essential.
Undoubtedly the very best results
are obtained with such a plate as
the Panchromatic, but these are
perhaps a little troublesome to
develop, and quite satisfactory
pictures can be taken on any
of the ordinary colour sensitive
plates. I have used Barnet
Chromatics for several years, and
have no reason to change. There
is no point in selecting an exces-
sivel\- rapid plate, I'or blue, red
or orange flowers a colour screen
is, of course, necessary, Init it has
to be remembered that the use
of a colour screen, even of the
palest tint, doubles or quadruples
the exposure, and makes the
struggle with the worst enem\-
of the plant photographer — wind
— all the keener. Not infre-
quenth'. therefore, the colour
screen will be dispensed with,
and a fairly satisfactory result
obtained nevertheless. Occas-
ionalh- also a special point in the
picture can be emphasised, or
made to stand out more clearly
b\' intentionally over- or under-
correcting the colour values. For
mstance, the yellow stamens of
a white flower are more distinctK-

seen when
used, but a

no
vel

,'ht filter
■ floN

will

The (Trecn - winged Meadow Orchis

[Orchis Moi'io). Photographed iiatunil

siiie and magnified four diameters.

colour values are

rock if the

slighth' over-corrected. Some-
times the same result can be even
better obtained by the use of a filter of red, blue,
or green, or some other intermediate tint, or In-
making part of the exposure with one filter and
part with another. I have tried this with success,
but have generallv foundthat.it requires too much
consideration in planning and too much care in
carrying out to be of much practical use in the field.

Colour Photography.

But to obtain the very best results it is necessary
to photogra[)h plants in their natural colours.
Nothing can exceed the beauty and charm of a
flowering plant growing in its natural home and

392

KNOWLEDGE.

October. 1911.

photographed in its natural colours. Those \\ho'^m(H)t point. .\
have once started colour work will never
return to the old

willingh"

niediatch-

monoch rome.
myself. I can
speak of the

For

oiih'

autd-

chroine jirocess. but
I have found this so
perfect that I want
nothing better. .\nd
it is realh" sunpler
than iirdinarv photo-
grajdix-. .\ single
exposure is alone re-
quired and the photo-
graph can be finished
in a cpuirter of an hour.
^^■ith tile help of a
meter to calculate
the e.xact exposure I
find that I hardly
ever s[)oil an auto-
chronie plate except
as the result of some
technical error in the
arrangement of the
plants or on account
of wind.

blil.KCTIO.X (IF
Sl'HJKCT.

It is dit^cult
useful hiiUs as
tl

Tlic Wood I'iii
>hc)\v the rflcct

FiGURr; 5.

. UJiciiitliiis ^ylvcstns). To
ut a luitiiral bLickgnniiul mil
of focus.

to
to

iw an\-
the selec-
tion of the subject to photo-
graph, for different people have
\ery different ideas as to tile effect
tliey desire to obtain. With some
a pleasing and natural ()ictur(.- i-
the chief aim, but others tr\- to
combine with this a l>otaiiicali\
correct portrait of a pi uit or pail
of a plant, arranged to displax its
cliief characteristics, such as buds,
leaxcs. fruits, and so on. Generally
it iiia\ be said that the best results
will oiil\ be obtained by those who
know at least something of the
subject they are trying to photo-
graph. The individual, for instance,
howe\er i)rohcient he nia\ In- as
a photographer, who caii'fulK'
arranges buttercuj) leaves among a
grou(j of po[)pies. where the foha.i^e
appears a little deficient, will not
obtain a satisfactory picture. Not
infrequently a small group of
plants looks nicer than a siiigli'
specimen, and wherever possible, it
is wiser to select sometliing com-
pact and not very large, rather
than a straggling mass. How-
tar " faking " is permissible is a

.\ rare l-^iiigus \llydniun i iiiidccii in).

Photograplied in a hollow tree on a foggy

November day. in pouring rain, and given

15 minutes" exposure at 1'" 11.

little judicious weeding im-
aroLind the jilant to be photo-
graphed often makes it stand out
much more clearly, ami the same
result is sometimes obtained by
piishing awav and [jressing down
the other plants which surround
it. It is generall)' desirable also
to remove anv foreign jdants that
are growing among the group
selected and sometimes the careful
removal of a few dead or faded
lea\es. or e\en flowers, seems to
do good. Where we find a rather
straggling group of flowers with
considerable de[ith of focus it is.
I think, sometimes permissible to
place a stone behind tlieiii in such
a position that it cannot lie seen
ti-om the front, so as to throw
forward the flowers at the liai k
and liring them more in line wUli
llie reniainder.

Whether anxthing further is
i\er to lie thouglit of is very
uncertain. Whether, for instance,
one or two buds shoulil be added
to a plant which is well pro-
portioned and otherwise makes a
pleasing jjicture but is deficient in
tliis particular. Certainly, if Nature
IS to be assisted in an\- way, it
needs to be done most
carefulK-. Moreover,
if there is the slight-
est breeze it will
lie often found that
while the plant as
a whoK returns
to its former posi-
tion in the intervals,
the additions do
not, and a spoilt
plate results. l'"ur-
ther. where the
exposures are long,
as in colour work,
what nia\ be <le-
scrilied as " fading
to,L; " has to be reckon-
ed w ith. Where the
connection between
the brancli or flower
and its root is severed,
fading takes place
and in plants grow -
in;,; in moist places
this ina\- be so rapid
as to entireU' spoil
the picture after an
exposure of five min-
utes. 1 lad 1 not had

(ICTORHI;, 1911.

KNOWLEDGE.

393

one or two unfortunate experiences in this \va\- I
sliould not have beheved it possible.

Back(;rounps.

.\lthough I ha\"e repeatedly made the attempt. I
have never been able to produce a satisfactor\- result
by using an artihcial background. I have tried sheets
of paper of various tints, supported in various ways
or kept in movement by an assistant. Even where
the motion does not extend to the plant, as ver\'
easily happens, the result is, in mv experience, never
satisfactory. UnquestionabK- the best background
is the natural one, which, however, can be slighth-
modified where necessar\' bv the removal of anv-
tbing which will too prominenth' strike the eye, as
lor instance, a single large stone or a ver\- noticeable
plant of a different species. Plants of the same
species, perhaps a little out nf focus, seem to me
rather to improve the general effect. In colour work
special care must be taken of this point. A bright
\ellow buttercup. e\en if rather blurred in outline,
behind a group of blue forget-me-nots catches the
eye. and directs attention to itself more than to the
subject of the picture. To mv mind bv far the
best result, both pictorially and diagramaticalh', is
obtained b_\- the use of a natural background rather
out of focus. There are three points to be borne in
mind in obtaining this desired result. With the
camera looking down obliqueh' at the plant, and the
swing-back used as described in the earh" part of
this article, the background is almost certain to be
indistinct. Where the plants to be photographed
are growing amongst others, the immediateh'
surrounding \-egetation, and especiall}' that behind
them ma\' be pushed aside with the hand or even
pressed down with the foot. And lastly, b\- verv
careful focussing and the use of the largest possible
stop consistent with obtaining the required depth of
focus, an indistinct background is obtained. In
plant portraiture, no less than in human, the most
artistic results are obtained b\' a somew hat indefinite
background.

Wind.

In connection with field-work the greatest enem\"
of the plant photographer is wind. However calm
it may appear, there are \-ery few occasions, except
soon after dawn and just before sunset, when vegeta-
tion is absolutely at rest. Of course, tall flimsy
things like sedges and grasses are most affected, and
short solid things like toadstools feel it least or not
at all, but there are realh- \er\- few occasions in ordin-
ar\- field work when the wind has not to be considered.
This will be the more evident when it is remembered
that the exposures in plant photography are generally
long, as a small stop has to be used. Frequently, for
instance, I have had to give four to five minutes on
a dull da\' with the ordinary plates, and five to ten
minutes exposure is quite the rule, even at noon in
the middle of the summer, with autochromes. The
simplest method of obviating the effect of wind is to
make one's exposure a few seconds at a time while

the plants are quiet, for where Nature has not been
assisted we can safely trust our sitters to return to
exactly the same positions between the gusts. One
must not necessarih' conclude that a photograph will
be entirely useless because there has been a certain
amount of movement during some part of an
exposure. Even where failure seems assured, it is
just as well to develop, and sometimes the result will
be an agreeable surprise. As a direct shield from
the wind an umbrella or sunshade, preferabK- of a
light colour, is exceedingly useful. .A very little
ingenuity in the placing of the camera and umbrella
is sufficient to ensure that the latter does not appear
in the photograph. One or more long-suffering
friends who are capable of remaining in one position
for several minutes, particularly if wearing overcoats
or full skirts at the time, are also much to be desired.
But as these aids, however desirable, are not always
to be had, the plant photographer is advised to pro-
vide himself with what may be termed a " wind
screen." .\ simple and useful form mav be made as
follows. Obtain a piece of stout white calico, six or
eight feet long by fourteen inches wide and half-a-
dozen fifteen-inch steel knitting needles. Roughen
each knitting needle near one end b\- twisting some
thin wire around it and soldering it to the knitting
needle. Get someone to stitch four pieces of tape
each fourteen inches long at equal distances along
the strip of calico and one at each end, slip in the
knitting needles and sew them firml}- in place near
one end so that the other end projects an inch. The
apparatus is now- complete. It is arranged on three
sides of the plant w ith the camera lens looking o\er
the middle of the enclosure and the whole thing
strongh- suggests a "coco-nut shy" on a small scale.
It is wise to put the camera into position and roughly
focus the plant before putting up the enclosure.
Where a taller screen is used, it is desirable to have a
slit cut in the calico near its middle, (with some
hooks and eyes to close it if vou like), through which
the camera lens can be made to project. The onh'
objection to such a screen that I know of is that it
cuts oft" a certain amount of side light, and can hardlv
be used to completely surround the object, unless the
camera is looking down on it more or less obliqueh'.
Less light is cut off than might be expected, for the
white calico reflects a good deal and is sometimes
useful for this reason alone when there are heavv
shadows. .\ more complete enclosure can be made
by using a transparent material. Sheets of trans-
parent celluloid about thirt\-six inches by twenty
can be obtained at any large photographic dealers
for eighteenpence or thereabouts. It is easv
to cement two or more of these together with
collodion, which can be bought at any chemist's,
allowing an overlap of half-an-inch. Strips of
broad tape to enclose the steel wire standards can
easily be cemented to the celluloid sheets with
the same material. As the collodion softens the
sheets it is best to let them dry between a couple of
boards. A group of plants can be entirely surrounded
by a screen of this sort, for a very pleasing eftect is

394

KxowLi-.nr.E.

October. 1<)11.

obtained by photographing the natural background
through a celluloid sheet. Or a combination of the
calico and celluloid screens is often quite successful.
I generally carry a couple of spare sheets of celluloid
and a dozen tie-clips, and w ith these it is quite eas\-
to roof in the little enclosure, and effectiveh' prevent
any mtn'enient of any but the most fragile of
plants. In calculating the
exposiux'. it is necessar\' to
remember that an appreciable
amount of light is absorbed hv
the celluloid.

Lu;hting.

People often remark ho\\
niceh' the lighting of m\' [ihoto-
graphs is arranged. l>ut I am
hardl\- ever conscious of giving
the matter anv consideration
at all. Certainh- the calico
\\ ind screen set rather obliqueh-
does reflect up a good deal of
light. Occasionally, w here there
are \er\' deep shadows, a piece
of ne\\s[)aper King on the
ground just in tront of the
plant, but so arranged that it
does not appear in the picture,
ma}- also be useful. But
generallv speaking, seeing that
our object is to obtain as
natural - looking pictures as
[K)ssible, the less we trouble
about the lighting of our sub-
ject the closer to Nature will
our result pro\-e. Photo-
graphs should ne\'er be taken
in direct sunlight, for the dee[)
shadows are devoid of detail
and mostK' unsightK', Alwa\s
stand between the plant
and the sun or use an
umbrella.

EXPOSURR.

If you want to economise time and mone\-, buy an
exposure meter and use it. Use it at first in ever\-
case, for the difference of light value in a wood
or beneath a hedge, compared with that in an open
field is very considerable. Place the exposure meter
as near as possible to the object to be photographed,
and read off the exposure, allow ing for the size of the
stop and the variety of plate used. Multii)ly this b)-
three if you are photographing about half natural
size, by four if you are photographing, roughlw
natural size, and by six if \ou are taking tlie
plant a little bit enlarged with a much extended
camera, but without any extra front lens. The
reason for this increased exposure is that the
size of the stop, as indicated on the lens, is
only correct when distant objects are [ihoto-
graphed, and when the camera is extended as in
photographing an object about natural size and the

distance of the plate from the lens is approximately
doubled, the number representing the size of the
aperture is in realit\- double that indicated. For
instance, if wi' appear to be using F32 while jihoto-
graphing an object natural size we are in realit\-
using F64, ancf as everyone knows this aperture
will require four times the exposure of FJ2 for
the same conditions of light.
Unless the plant photographed
is absolutely free from deep
shadows, it is wise to multiph'
hv two again. There are note-
wortlu" excejitions, but it is a
general rule that most plate
makers [uit a \'ery liberal
estimate on the speed of the
[)lates the\' manufacture, and
it thirtx' per cent, or so is
deducted from the speed given,
the exposure calculated will, in
tuost cases, be the more correct.
In all cases, if we err at all, it
is better to err on the side of
over-exposure. Where the test
paper of the exposure meter
takes several minutes to change
ctilour, as in studio work, or
outside in very dull weather, it
is often convenient to expose
at the same time that the
exposure is being calculated.
I use a Wynne meter and as
soon as I have started exposing
I set it uj) so that it is receiving
the same light as my subject,
but is just outside the picture.
Using plates of speed 100 and
photographing natural size, I
find that when the test paper
has changed to the lightercolour
ni\ exposure is correct for a
16 stop (which is reallv 32 as
the camera is doublv extended),
and when the colour has changed to the deeper tint
I am all right for F52 (really 64). In autochrome
work the exposure is estimated very simply. Using
the Wynne meter, we know that the time taken for
the test paper to reach the darker tint is the correct
exposure for a landscape at Fll. For jihotographs
of objects taken approximately natural size^ we
multiph' b\- four, and if there are any shadows at
all b\- two again. Allowance for every stop other
than I'll is made according to the ordinary rules.

STrnii) Work.

In conclusion. tua\' I atid one or two hints as to
studio work. My experience in this part of the
suliject has, however, been much more limited. The
accompanying photograph of the apparatus I use
will explain itself. It consists of a base with a
slotted wooden standard soiue four feet long.
Moving up and down on the standard, but kept in

Camera.

October. 1911.

KNOWLEDGE.

395

line by pieces of wood that fit into the slot, are a half-
plate camera mounted on a bo.x. and a carrier to hold
a 12-in. bv 10-in. sheet of glass. The carrier is open in
front to avoid an\- shadows on the background placed
below, and both carrier and camera are clamped in
position on the standard hv thumb screws. The
tense copper w ires greatly increase the rigidity of the
whole thing. The apparatus is used in an ordinary
room close to the window, or preferably in a hay
w indow. porch, or greenhouse, or even outside. The
plant to he photographed rests on the glass plate,
and about three or four inches below it, to avoid
shadow s, is placed a sheet of white or grey cardboard.
A verv dark or black background is in this situation
unsatisfactor}-, for the glass plate then becomes a
looking glass and a double image of the plant is
seen in the photograph. \\'here a black background
is required the plant rests directly on a sheet
of dull black paper which is supported on the glass
plate. For colour work an interesting background
is often made bv a sheet of white cardboard w ith
one or several la\"ers of "chiffon" of different tints
laid on it. Gi\en a dozen or more pieces of
■' chiffon."" a thin silky material, dyed half a dozen
different colours, almost any tint can be built up.
If the background is some three or four inches away
it will be sufticientlv out of focus to prevent any
slight irregularities in the material appearing in the
photogra[ih. This point should be tested before

exposure by a careful inspection after the lens has
been stopped down sufficiently. Of course, it is by
no means always necessary or desirable to lay the
plant down to photograph it. Often much more
natural results are obtainable if the plant is held
erect in a vase of water, being sure that the vase does
not appear, with the background sufficiently far away
from it to be thoroughly out of focus. Even in this
position a sheet of glass immediately behind is often
of value, for it limits the depth of focus of the picture
and gives support to flimsy plants. In photograph-
ing plants we must remember that we are dealing
with li\ing things which actually move, especiallv
when an\- change takes places in the equilibrium of
their water-vascular system. Hence it is unwise to
pick flowers on a hot summer day, put them in a vase
of water and immediately give them a prolonged
exposure. Rather should they be left in water for
at least two hours so that the cells of the plant may
accustom themselves to an abundant water supplv.
.\gain, when flowers are taken out of water and put into
position to be photographed it is just as well to cover
the cut stalk, if it does not appear in the photograph,
w ith a small piece of moistened cotton-wool to prevent
"fading fog."' \\'here the light is poor both in the studio,
and the field, focussing is greatly assisted by placing
a small scrap of printed paper close to and in the
same plane as the principal object to be photographed,
of course removing it before the exposure is made.

SOLAR I)ISTURHANCP-:S DrRlXCx ATGL'-ST. 191 1
Bv FRANK C. DENNETT.

DlRlNG August the disc appeared to be quite free from
disturbance on the 1st. 4th and 26th until 31st. whilst only
faculae were seen on the 2nd, 3rd and ISth until 25th. The
longitude of the central meridian at noon on .August 1st was
15° 29'.

No. S2. — The most conspicuous outbreak of the month, first
seen within the limb on the 5th. The umbra of the large spot
was bridged on the 7th. and h.id an e.xtension eastwards, with
a small companion following. During the 8th and 9th other
spotlets formed, and changed, indicating considerable activity,
and the inner border of the penumbra of the large spot was
bright from the 7th until the 10th. Only a minute pore
remained as its solitary companion on the 11th, when the spot
had dwindled considerably. On the 13th, there were two
closely placed umbrae, and on the morning of the 14th, when
last seen, only one. The maximum diameter of the spot was
over ten thousand miles, and the length of the group over
forty thousand miles.

No. 5i. — Two pores amid brilliant faculae had come round

the limb on the 13th, the rear one being 2° farther north, and
a similar distance eastward of the leader. They died away
on the 15th.

No. 34. — A pair of pores three degrees apart had broken
out on the 15th. next day the rear one had closed up. but the
area appeared disturbed, and on the 17th, when last seen, the
pore appeared cut in half by a bridge.

No. 35. — A solitary pore only seen on the 16th. There
may be a very small error in its position. The dotted areas
upon the chart indicate the positions of faculic areas ; that
around No. 34 being observed on the 7th and Sth : that at
205° from the Sth until the 10th. The group around longitude
153° on the 13th. Not the least interesting facuUc distur"bance,
however, was a bright group on the 19th, in 60° south latitude
near longitude 67°, seen until the 23rd, though its brilliance had
decreased. The general granulation of the disc appeared
coarse over the south-eastern quadrant on the 27th.

Our chart is constructed from combined observations of
Messrs. John McHarg. E. E. Peacock, and E. C. Dennett.

ips

l;?8

?''

2,6

25

?4

2,3

2,3

DAY

V 2P 19

OF

',7

Al

;gls'i

15. It

1?

K
1

)1I
2

1,1

to

<

}

9

J

9

5

A

51 3 30

^^

1?

s

20
0

nl/

1°

10

^\

20
50

N

30

N

33

35

it

fCD

0 0 20 33 "tO 50 63 70 8J M 101 110 i20 150 140 ISO 160 170

190 XO aO 120 230 2W 250 260 270

290 300 Jio m m no jso xo

THE FACE OE THE SKY EOR OCTOBER.

Bv \V. SH.VCKLKTON. F.R..\.S.. .\.K.(".Sc.

The Sun. — On the 1st the Sun rises at 6.0 and sets at 5.40 ;
on the 31st he rises at 6.52 and sets at 4.36. Conspicuous
Sun-spots and faculae are not to be expected at this phase of
the eleven-yearly cycle, but smaller displays may occasionally
be visible. The positions of the Sun's axis, centre of the disc,
and heliographic longitude of the centre are given in the
following table :

Date.

Axis inclined

Centre of Disc
N. of Sun's

Heliographic
Longitude of

from N. point.

Equator.

Centre of Disc.

Oct. 3

26' 13T.

6" 35'

263° 19'

8 ...

26° 25' K

6° 18'

197° 20'

.. 13 ...

26° 2^'K

5° 5S'

131° 23'

,, iS ..

26° 14'E

5° 35'

6s° 26'

,. 23 ...

25° 52'E

5° 10'

359° 29'

.. 28 ...

25° 19' F.

4° J3'

293° ii'

.\nv. 2 ...

24° 33'K

4° 13'

227= 37'

7. 7 ■•■

23" 35'K

3° 41'

161° 41'

An Annular Eclipse of the Sun occurs on the 22nd, it
is invisible in this country, but visible as a partial eclipse
in India and Australia.

The Moon : —

Date.

Phases.

H. M.

Oct. S ...

„ 14 ..
,, 22 ...

„ 30 .
Nov. 6 . .

0 Full Moon

't Last Quarter

9 New Moon

]) First Quarter

0 Full Moon

4 11 a.m.
11 4(1 p.m.
t 0 a.m.
0 41 a.m.
3 4S p.m.

Oct. 12 ...
., 27 ...

Perigee .

Apogee

6 36 a m.
10 36 p.m.

OccuLT.'iTIONS. — The following table gives particulars of
the principal occultations visible from Greenwich : —

Date.

St.-ir's

3

Disappearance.

Reappearance.

An^le

Angle

Mean

from N.

Mean

from N.

S

Time.

point.

Time.

ponit.

p.m.

a.m.

Oct. 3

37 Capticorni ...

5'7

11 4S

a.m.

355°

0.16
a. III.

306°

6

^' .Atjuarii

4' 5

2.16

a. 111.

353"

2.43
a.m.

302°

6

\f/- .Aipiarii

^•0

2 49

a.m.

86°

a. 111.

—

„ 13

B.A.C 1754

5'7

I-3I

p.m.

110°

2-3>
p.m.

226°

„ 2$

B.A.C. 662S ..

5'9

6. IS

26"

7.10

305°

Mercury : —

THE PLANETS.

Date.

Right Ascension.

Declination.

Sept. 29 ...
Oct. 9 ..

„ 19 •■■

„ 29 ...

Nov. 8 ...

h. ni.

1 1 19

12 20
>3 23

14 23

15 27

N 6" 6'
S 0° 7'
S 7° 32'
S 14" 20'
S 19° 53'

Mercury is a morning star until the 23rd, when he will be
in superior conjunction with the Sun. The planet may
possibly be observable during the first week of the month,
when he rises, almost due East, more than an hour before the
Sun.

Venus : —

Date.

Right Ascension.

Declination.

li. 111.

Sept. 29 ...

10 S2

S o^' 26'-

Oct. 9 ..

10 52

N 1° 50'

„ 19 .

II s

N 2° 38'

„ 29 ...

II 28

N 2° 3'

Nov. 8 ..

II 59

N 0° 20'

Venus is a morning star throtighout the month, rising,
almost due East, at 3.10 a.m., on the 15th. The planet will
be at its greatest brilliancy on the 22nd, and its angular
distance from the Sun will continue. to increase until it reaches
greatest westerly elon.gation, on November 26th.

M.\Rs:—

Date.

Right Ascension.

Declination.

Sept. 29 .
Oct. 9 ...

,, 10 ...

,, 29 ...
Nov. S . ,

h. m.

4 28
4 36
4 --S
4 34
4 23

N 20° 28'
N 21" 3'
N 21° 30'
N 21° 49'
N 21° 58'

Mars is now approaching opposition (November 25thl, and
will be well placed for observation during the later hours of
the evening. The planet rises N.E. by E.. about eight p.m..
at the beginning, and about six p.m. towards the end, of the
month. Its apparent diameter increases during the month
from 14"- 1 tol7"-5. The planet will be easily identified if
looUed for about five degrees to the North of Aldebaran. The
South pole of the planet is turned towards the earth.

Jupiter : —

Date.

Right .Ascension.

Declination.

Sept. 29 ...
Oct. 9 ...

,, 19 ...

„ 29 ..

Nov. 8 ...

h. m.
14 49

14 57

15 5
15 14

S 15° 2%'

S 15° 59'
S 16° 3.;'
S 17° 11'
S 17° 45'

Jupiter is nominally an evening star throughout the month,
but he is very low down in the Sonth-Western sky at sunset,
and as he sets about an hour after the sun, he can only be
observed with difficulty.

The configuration of the Satellites as seen in an inverting
telescope, and observing at six p.m., are as follows : —

396

OcxniiFR. 1911.

KNOWLEDGE.

.i')7

nay.

West.

E.ast.

Da)'.

West. 1

East.

I

3

0

214

11

42 c

3 i»

2

31

1 )

24

12

41 c

23

3

32

0

4

13

4 0

•13

4

2

0

134

14

421 U

J

5

I

0

234

IS

a 0

I

b

U

2143

16

31 0

42

7

214

0

17

32 C'

14

8

43

iji

I 2«

iS

2i U

4

9

431

^^1

2

19

I 0

234

lO

432

0

I

20

0

1234

The circle (O) represents Jupiter; © signifies that the
Satellite i.s on the disc : • signifies that the Satellite is behind
the disc or in the shadow. The numbers are the numbers of
the Satellites.

S..\TURN : —

Date.

Right Ascension.

Declination.

Oct. I ...
., 16 ...
„ 31 ...

h. m.
3 II
3 S
3 3

N 15' 12'

14" 56'

N 14" 37'

Saturn may now be conveniently observed during the
evening, as he rises, in the E.N'.E., at 7.8 p.m. on the 1st, and
at 5.6 p.m. on the J 1st. The planet is a conspicuous object,
some distatice to the west of Aldebaran and Mars, and cannot
be mistal<en. The rings are well open, the outer major and
minor a.xes being respectively 47" and 17", and the inclination
of the plane of the ring to our line of vision being 21. The
Southern pole of the planet is presented towards the earth.
The planet has eight satellites : of these, Titan (magnitude S'5i
can be observed with a good objective of two inches aperture,
lapetus (magnitude 9-12) may be seen at westerly elongation
with a telescope of three inches aperture, which is also
sufficient to show Rhea (magnitude 9.51 and Tethys
(magnitude 10), whilst Dionc (magnitude 10'5) requires an
aperture of four inches.

The three other satellites require larger telescopes since
their magnitude is less than 12.

Uranus : —

Dale.

Right Ascension.

Declination.

Oct. I ...

Nov. I ...

h. m. s.
19 49 57
19 5' 10

S 2i« 36' 39"
S 21'' 32' 48"

Uranus, in Sagittarius, can only be ob,served in the early
evening during the present month, and is too low in the sky to
be well seen. The planet sets about 11.14 p.m. on the first,
and about 9.17 p.m. on the thirty-first. It can be distin-
guished from neighbouring stars by its small greenish disc of
3i" diameters, if viewed with sufficient magnifying power.
After October 6th, when the planet is stationary, the motion
will be direct, or easterly.

Neptune : —

Date.

Right Ascension.

Declination.

Oct. I ...
Nov. I ...

h. m. s.
7 41 26
7 42 15

1

N 20" 49' 23"
N 20" 47' 7"

Neptune is not yet very conveniently placed for observation,
as he does not rise before 11 p.m. at the beginning of the
month, nor before 9 p.m. at the end. The planet is located in
Gemini, nearly midway between 68 Getninorum and
■■f- Cancri. The motion is direct, or easterly, until the 28th,
when the planet is stationary.

Meteors : —

Radiant.

Date.

K.A.

Dec.

Oct. 2 ...

230°

N. 52"

Slow, bright.

4 ■■•

310°

N. 79°

Sluwish.

,, s ...

77"

N. 31-

Swift streaks.

„ 8-14 ..

45"

N. 58°

Small, short.

„ 14 ..■

133°

N. 68°

Rather swift.

,, 15 ...

3'"

X 9°

Slow.

„ 18-20...

92°

N. is"^

Swift, streaks.

„ 23 ...

100^

N. 13°

Swift, streaks.

,, 29 ...

109

X 2f

Very swift.

The principal shower is that having its radiant point near
i- Orionis, and hence known as the Orionid shower ; the
maximum display is froni the ISth to the 20th.

At.Goi,. — Observable minima of Algol occur on the 12th
at ten p.m., and on the 15th at seven p.m. The period is
2'' 20" 49".

Telescopic Objects : —

Douiii.E St.\rs.— 7 Arietis, l''48'", N. 18° 48', magnitudes
4-2, 4 • 4 ; separation 8" ■ S. Easy double, with a power of 30 ;
the first double star telescopically observed.

7 Andromedae l** 58", N. 41" 51', magnitudes 2-1, 4-9;
separation 10". The brighter component is intensely yellow,
whilst the other is greenish-blue. The fainter star is a binary,
the components of which are tiow less than half a second
apart.

Nebul.^E. — The Great Nebula in .Andromeda 3lM, easily
visible to the naked eye, and readily distinguished by the aid
of an opera glass, in the neighbourhood of ■' Andromedae.
Seen with a three- or fonr-inch telescope, it appears as an
extended oval with a bright nucleus, and has often been
mistaken for a comet. Spectroscopic observations suggest
that it is built up of a vast number of stars.

(32m) Nebtila about 2° to the South of the Great Andromeda
Nebula. It is fairly round and appears like a star out of
focus.

(18'J) lies about the same distance North of the great
Andromeda Nebula that 32M does South ; it is faint, but large
and elliptical.

Comets. — Observers who possess a pocket spectroscope,
or its equivalent, will find it of interest to examine the spectrum
of Comet Brooks, even if the telescope has only an aperture of
two or three inches. The three typical bands of cometary
spectra, in the yellow green, green, and blue, we re easily
visible under these conditions at the time of writing (September
16th). The slit should first be placed at the focus of the
telescope by observations of a bright star, the spectrum of
which should appear as a narrow streak when the adjustment
is made. The image of the comet may then be brought on
the slit with the aid of the finder.

Comet Brooks (1911 c) is visible to the naked eye as a third
magnitude star, but with a pair of binoculars the nebulosity
round the nucleus may easily be seen. The comet is moving
on the confines of Ursa Major and Botes towards Leo and
at the beginning of the month is situated about 5° S of ?; and
Ursa Majoris, the star at the tip nf the Bear's tail.

REVIEWS.

CHEMISTRY.

A't'w Ideas on Inorganic Cliciiiisfrv.—'By Dr. A. Wkr.ser.
Translated by E. P. Hedi.ev. Ph.D. 268 pases. 9-in. x 6-in.

I Longmans. Green and Co., Price 7 6 net.)

This is among tlie most valuable contributions to the science
of Chemistry which have been made of recent years. The
first edition was published in Germany in 1905, and within
three years a second edition was required. The present
booU is the translation, with some additions and corrections,
of this second edition.

It deals, in the main, with the problem of the valency of the
elements as shown in their different compounds, and while
outlining the various theories that have been put forward,
attempts to weave them into a consistent f.abric, and discusses
their relationship to the observed facts.

Although the systematic classification of inorganic com-
pounds does not as yet rest upon so stable a basis as that of
organic compounds, indications are not wanting that before
long such a scheme may be de\iscd. In fact this book goes
a long way in this direction.

Both as a critical history of the doctrines of \alency and a
guide to unexplored fields, it should meet with a welcome from
all chemists, and in particular from those whose work involves a
consider.ation of the structural constitution of inorganic com-
pounds. The book is excellently translated, though there are
a few grammatical slips, and is clearly printed and arranged ;
but although there is a full table of contents at the beginning
of the book, the absence of an index is a blemish. Its use as
a handbook to research would .also be greatly increased by
repeating the references given at the foot of each page in a
classified bibliography, CAM

Inorganic Clu'inistry..~By V. Stanley Kipping, D.Sc,

F,K.S., and W, H. Perkin, D.Sc, F,R,S, 751 pages. 120

illustrations. 7i-in. X Sl-in.

I\V. & K. Chambers. Price 7 6.)

So great is now the number of elementary text-books of
Chemistry that any fresh addition to them needs to justify its
existence by novelty of treatment or arrangement. In the
present case there is undoubtedly such justification, the
subject matter being so arranged as to avoid some of the
pitfalls in the way of the beginner.

All who have had experience in teaching will recall the
difficulty of convincing a young student of the reality of an
invisible body, and of making him grasp the fact that a salt in
solution has as real an existence as an insoluble compound.
This was summarised by Professor Vernon Harcourt in his
phrase, that "a precipitate is too often an object of super-
stitious veneration."

To obviate this difficulty the authors of this book ha%e
wisely postponed the consideration of the gaseous elements,
with which most text-books start, until such time as the
student shall have acquired a practical acquaintance with the
reaction of common salts.

The first part covers the ground needed for the London
Matriculation examination, while in the second part chemical
and physical changes are dealt with more fully, and sections
upon tlie determination of molecular weights, ionic dissociation,
spectrum analysis, and radioactivity are included.

In this part also comes the systematic account of the
elements. The interest of the student is likely to be main-
tained by the way in which metallic and non-metallic elements
have not been isolated from one another.

Throughout the book, experiment goes hand-in-hand with

theory, and although the utilitarian end of examinations is
not lost sight of, it is not unduly emphasised.

We can, therefore, heartily recommend the book to any
beginner who wishes to study Chemistry without the necessity
of following set courses of lessons,

C. A. M.

GE()(";RAPHV.

Mdilcrn Ccitfirapliy.—lh- Marion 1. Nkwbigin. D.Sc.
256 pages. 13 illustrations. 7-in. '^ 4-in.

(Williams \- Norgatc. Price 1 - net.)

This little book forms part of the Home University Library,
and is an excellent compendium of the different subjects
brought into relation mider the head of geography. The
standpoint is " frankly anthropological," geography being
considered as the study of the earth in relation to its inhabi-
tants, especially man. The chapter headings, however, raise
the doubt, at least in the mind of the reviewer, whether
geography is, after all, a unit of science like chemistry or
zoology. I'or instance, two of the chapters are geological,
others are botanical, zoiilogical or ethnographical. Is not
geography, therefore, rather the application of many sciences
to the description of the earth in relation to its inhabitants ?
Be that as it may, we have read Miss Newbigin's work with
great pleasure, and believe that it will give similar pleasure to
that section of the public which desires popular accounts by
competent specialists of the latest developments in knowledge,
A note on the literature and a good index is provided,

G, W, T.
GEOLOGY,

Characfcristics of Existing Glaciers. — By W. H. Horrs.
jOl pages. J4 plates. 140 figures. 9-in. X 6-in,

(New York: The Macmillan Co. Price 13 6 net.)

This important and authoritative work is by a distinguished
.■Vmerican glacialist whose mind has not been unduly obsessed
by the importance of the alpine type of glacier. Throughout
the book emphasis is placed on the contrast between mountain
glaciers — the alpine type — and continental glaciers, such as
those which cover Greenland and the .Antarctic Continent.
Hitherto, despite the enormous disparity in size .and shape,
the practice has been to treat these types together as if they
obeved the same laws and accomplished the same work. This
book takes the view that mountain and continental glaciers are
different in kind rather than in degree. In accordance with this
view, most space is allotted to the continental type as being by
far the largest and most important masses of ice. The ice-
caps covering small elevated areas, such as those of Iceland,
are regarded as in some measure intermediate between the
two types ; but physiographically they are allied to the
continental ice-sheets, and have few affinities with mountain
glaciers.

Professor Hobbs is a convinced upholder of the excavating
and eroding power of glaciers, in opposition to the school
which claims that glaciers exercise a more or less protective
influence on their beds. We think, however, that the author
assigns too little weight to the maturely considered views of
such authors as Bonney and Garwood as to the protective
influence of glaciers. In regard to mountain glaciation, much
importance is given to cirque-recession as one of the chief
erosional methods of small bodies of ice, in strong contrast
to continental ice-masses, whose chief method of erosion is
by abrasion of their floors.

One of the most useful features of the book is the way it
summarises and collates the ice-observations of numerous

398

OCTOltKR. 1011.

KNOWLEDGE.

399

lecent Arctic and Antarctic expeditions, down to tliose of
I'eary and Shackleton.

The book is excellently and profusely illustrated. Each
chapter is accompanied by a fnll list of references, and an
adequate index is prox'ided. We welcome it as an excellent
reference work to modern views of glaciation, the literature of
which is widely scattered, enormous in its extent, and to many
workers rather inaccessible. (i. W • T.

Tlic History o/ Geology. — By H. B. Woodward. F.R.S..

I'.G.S. History of Science Series. 154 pages. 14 plates.

6i-in. X5-in.

(Watts & Co. Price 1 - net. I

As a science, geology dates from the close of the eighteenth'
centnr\ . although many vague and curious notions as to the
constitution and structure of the earth were current before
this time. These ideas were originated by speculation about
earthquakes, volcanoes, springs, land,slips, and other natural
phenomena. Mr. Woodward goes as far back as the philo-

sophers of Greece and Rome, in his search after iiuotations
which seem to prove that the germs of some modern geological
ideas originated in very early times. .After a chapter on these
early notions, the author passes on to review the work of the
founders of modern geology, Hutton, Werner, and their con-
temporaries, whose work made possible that '" golden era" of
geology, the giants of which were Sedgwick, Murchison, Lyell.
Von Buch, and Elie de Beaumont. It is gratifying to note
the predominance of British names in the history of geology.
So much has the pioneer work of British geologists impressed
itself on the science that the common local stratigraphical
terms, such as Lias. Devonian, Silurian, and so on, coined in
this country, are now used all over the world. In regard to
petrology we miss a reference to the recent work of Whitman
Cross on the history of that branch of the science. Mr.
\\'oodward is to be congratulated on this thoroughly readable
and useful little book, which supplies an undoubted want in
the literature of geology. It is illustrated by fourteen excellent
portraits of f.amous geologists, including Miss Etheldred
Benett (1776 — 18451, the first lady to distinguish herself by a
svstematic studv of the science. G. W. T.

METEORIC PHE.\()Mi:XA Ol- SEPTEMDER 2nd, 191 1.
Bv \V. E. Dl-:X\IXr,. E.R.A.S.

Therk were some beautiful fireballs observed on September
2nd. and the date was already known as one on which these
objects are apt to appear with unusual abundance.

In the sunshine of the afternoon, at 3.45 p.m., a splendid
meteor was seen from various stations in Cornwall and Devon.
Situated beyond the Bristol Channel, it could not be well
observed from N.E. counties. Observed from Newquay, it
was described as being like an elongated or pear-shaped
electric bulb with a tail, travelling at great speed and emitting
a brilliant white light.

At Laimceston the meteor fell in the north, being directed
from the west, at an angle of about 45'.

At Redruth "a brilliant star with a tail " was observed
running to the X.X.E.

.At Polzeath it surprised some golf players, who noticed its
brilliant flash of silver light in the sky. Its direction was
from S. to \. .At Barnstaple it was alluded to as a meteor of
great lustre, travelling from S.W. to W. at fifty degrees above
horizon.

At Fowey it was seen as " a brilliant kite with sparks issuing
from the tail and travelling from X.X.W. to N.N.E."
Unfortunately these and other accounts are not sufficiently
exact — but it is hoped that descriptions will yet be forth-
coming and allow the real path of this daylight fireball to be
well determined.

On the same date, but when darkness had nearly closed in.
and the stars were shining as brightly as they well could with
the presence of a gibbous moon in the southern sky, another
grand meteor appeared, and the number of its observers
seem to have been legion. This time the locality favoured was
transferred to the North Sea and Scotland, for the meteor
took a long and rather slow flight over Berwick, Edinburgh,
and Stirling, finally disappearing over Argyle when N. of
Inverary.

The spectators of it were distributed over a wide area, for
descriptions of its aspect and position have come from Leeds,
Manchester and North Wales in the South, from Dungannon,
Tyrone in the West, and from Rothes and Rothiemay in the
North.

All classes of people saw- it, from the untutored agricultural
labourer to the cultured savant, and some of the reports are
very good, though others are not without rather serious
discordances.

The meteor was one of the finest kind, for at Edinburgh.
Glasgow and other places not very far from its track its light
burst with astonishing brilliancy over the sky and landscape,

and some people mistook it at first for a very prolonged light-
ning flash, while others thought it due to the explosion of a
monster rocket. The light of a nine-day old moon seemed
pale and insignificant beside the splendour of the meteor when
it momentarily shone at its best.

It is not feasible to refer to the individual observations.
The statements as to colour differ but the nucleus appears to
have been of an electric blue, while the tail following it was
reddish-yellow.

I have compared about fifty observations of the object, and
find that its height was from about ei.ghty-eight to tw-enty-six
miles, directed from E.S.E. to W.N.W., along a path of one
hundred and ninety-six miles, traversed at a velocity of
nineteen miles per second. It was a member of awell-known
meteoric shower in Pisces at 348° + 3'. which supplies many
beautiful fireballs during the last half of .August and first half
of September.

Some of the observers did not witness the whole of the
luminous course. Many of them only looked up to the
heavens when the meteor's startling lustre attracted their
attention, and after it had already completed a large section of
its trajectory.

The meteor was probably the most brilliant object which
passed over Scotland since the great Leonid fireball of
.\o\ember 16th, 1910, described in " Kxowledgk." for
March, 1911, page 116.

The radiant South of the Square of Pegasus, in Pisces, has
previously furnished many fine meteors, and the following is a
summary of a few of the more interesting : —

Dale. -^h^g- Radiant.

1900, Aug. 19 3X2 ... 346°+ 0°

1901, „ 21 1st ... 341°+ 5°

1899, „ 24 +: ... 345°+14°

1899, Sep. S > 2 ... 347°+ 3"

1875, ., 14 > ; ... 348°+ 0°

1901, .. 14 2 ... 345°+ 1°

1898. .. 17 1st ... 343°+ 0°

1906, „ 27 2 ... 345°+ 2°

This year I saw several small meteors early in September
from this shower, but the fireball was too far north to be
visible at Bristol.

We have had here in Bristol a magnificent summer for
observing purposes. Between July 1st and September 22nd
(eighty-four nights) there were only two nights on which the
stars were inxisible.

sweepings;

]!v l"K]:i) KNOCK, K.K.S.

ElciicliKs

FllU'Rl 1.

tcilKiconiis. lai"\al
inch loiiL'.

Ai'c.rsT 22nd. ]')1K will long be remfiiibcnil bv
Mr. Chas. O. W'atcrhouse and myself as a "' red
letter da\',"" for we had swept the grass and herbage
in and about Richmond Park .so often without
capturing an\-thing particu-
lar, though we have both
swept man\- localities in
the hope of a prize, and
we have taken several firsts,
as well as specials, offered
to all who will enter the
arena open to ever\- one so
inclined.

The day opened threaten-
ingly, the clouds looked as
though thev had a thunder-
storm in hand, but it
cleared off and bright siui-
shine appeared.

We swept our crossing
backwards and forwards for
a couple of hoiu's without
much luck, just a few ot
our favourite Cdsmocdiini
fiiiilipeniiis (femalest, tlu'
male ot which we had
searched for for man\-
vears. I captured my first
female at Woking, in KS(S5.
and have been lookin,g for
the male ever since. I
intended to go on sweeping
for another ten minutes.
Mr. ^^'aterhouse had gone
on about a mile, when, on
taking m}- seat to examine
the contents of my net. I
ran mv eyes over the grass
seeds, bits of sharp-pointed
rushes, tumbling out the
numerous s[)iders. when ni\-
eve was caught b\- the
long filiform antennae of a
Cosmocomid with hairy wings. My
readv to be popped o\-er it. when a j,
spider intervened and 1 lost sight of my <]uarry —
but found it again and succeeded in getting it
into m\' phial, and corking it up. Then I saw
that after twent}'-five years " keepin' on," I had

sta.y

,Sn of an

FlGURM 2.

Hlcnchiis fciiii iconiis ifcinale).

[)hial

was

capturt'd the male ot Cosiikkoiiui fiiiiiipcnnis !

Thinking there might be another prize in my net,

I soon had mv lens in position, when I saw a tiny

insect buzzing about m the net. 1 instantly thought

— '-Wh)-! it"s a Sfylops or
its relative Hu/ict(ipJia}iiis."
.\s soon as the cork closed
on it I confirmed this. Mv
ten minutes was now up,
but I could not lease without
telling Mr. Waterhouse. so
1 hurried across m the direc-
tion he had taken, and as
I neared the wcioil I shouted.
■■ Waterhouse. I've got it I"
■■ ^^'aterhouse, I've got it I "
At last I heard the re-
sjionse, 'Ts that \ou shout-
ing. Knock. \\'hat ha\i'
vou got?""" Then the two
old boss camp-stooled to-
gether and revelled ni ex-
amining ni\ captures.

When I reached home my
buzzing Hdlictoplm^iiiis was
dead and mounted as soon
as possible.

I had turned and killed
nn- other captures, among
which were several Frog-
hoppers, and close to one,
an egg-like bod\-. with black
e\es. just one hundred and
twentieth part of an inch
long. Thinking it an egg
containing a Mymarid, I put
it under the (]uarter-inch
lens, and inuuediatel}" recog-
nised it as the hexapod lar\-a
of one of the Strepsiptera.
and no doubt, as I at first
imagined, of Hcilktopha^tis.
But on reference to West-
ssoikTs " Modern Classification of Insects," I identi-
fied m\- capture as Hlcnchiis fciiiiicontis (Templetonl,
of which but one examjile had hitherto been recorded,
over fifty years ago.

I am now searching for missing links in the life-
histor\- of this strauije insect.

400

NOTES

A. C

ASTRONOMY.

D. CkoMMEi.iN. H.A.. D.Sc. l-'.R.A.S.

STFLLAR PARALLAXES.— r/;f Astruphysiail Joiini.il
fur July contains an interesting paper by Frank SclilesniijLT
on llie pliotographic determination of stellar parallaxes with
the Yerkes' refractor. There has been a great advance in
accnrac\- in recent years, and the probable error of deter-
mination is of the order 0"-02. One general
resnlt derived is the great distance of the
helium stars; four fourth-magnitude stars of this
type are of sensibly the same distance as the
ninth-magnitude comparison stars. The following
table gives the parallaxes deduced whore thev
exceed 0"- 1 : —

Star ,!''"''• P:irall;iv.

Struve 2398 2" -28 "-2')

Groombr 34 2"-85 "-27

BD-f56'-2783 0"-92 ... ... "-2.^

\VB V 592 Z"-25 "-19

Lai 25372 2"-ii ... ... "-15

Lai 46650 l"-40 "-15

LallFn457,145H l"-69 "-15

WB XVII 322 l"-36 "■\4

At Cassiop 3"- 75 "-11

b Aquilae 0"-96 "-10

th

On October 4th it is 10 East of Cor Cuioli (a Canuni \'en.l.

On October 12th it is near /i Comae. On this day it is in
conjunction with the Smi, 36° North of it: after this it may
be best seen in the morning, though \ isible in the evening for
a few nights longer.

ENCKE'S COMET. — M.Gonnessiat gives in Astr. Nachr.
4518, particulars of his observations of. Encke's Comet on
July 31st and August 1st. ItsVfinding was the resnlt of

parallax

nnu'li Inighter

light was rc-

kcep its image

Wlirie
than the comparison
duced by a rotating

small and measurable. This plan worked very
successfully. He estimates that tlu' niunlur
of parallaxes that can be determined per annum
this telescope is equal to the nnmber of
plates being taken
jf each star during
the vear.

uitli

Inie nights, about thirteen

on each night, and thirteen

.rfi

r^

r-"

S

t

»

\

I

■

"

A

V

■";

N

k

■'4

\

V

\

V

•

>

L

1 1

\

is

10

\

\

V

NJ

V

i

>

V,

s

-^

t

1)1)

_

_

»»

^

COMETS.— The
19116 (Kiessi and

following revised elements of Comets
191 U- (Brooks) are by Dr. Kobold :—

}■„.,.. I

s.

1911

Oct

.27

152°

44'

18"

293°

10'

6"

34

0

3"

1911

•0

9-69036

object

s U

ol

( ..,iu\. Kicss.

Tin Berlin M.T. .. 191 1, June 30- 3093 1911. Oct. 27- 762

Omega 110 ii' 50"

Node 157 26' 21"

Inclination... ... 1 18 27' 25"

Equinox 1911-0

Log q. ... ... 9-83565 ...

Both comets were evidently difficult objects to observe
accurately, as there are large discordances which, in the case
of Kiess, suggest that the orbit differs sensibly from a paraliola.
This comet is now too far South to be seen in l-^ngland. and
has also sunk to the tenth magnitude, but Brooks' will be a
conspicuous naked-eye object in the evening sky early in
October. It was half a magnitude fainter than the Andromeda
nebula on August 29th, and its intrinsic brightness is likely to
increase considerably as it approaches the Sun. so thai it may
reach the second magnitude.

ICphemeris for 1 1 p.m. : —

K.A.

N.Dec.

K.A.

N.Dec.

Oct.

1.

..14 7 2

43° 10'

3.

.13 53 35

40^' 44'

5.

.13 41 18

38° 11'

7.

.13 30 6

35° 33'

Oct.

On September 30th it is 2 Soi
continuation of the tail ol the Great Bear.

9. ..13 19

56

:,2 50'

11. ..13 10

46

30 2'

13. ..13 2

34

27° 11'

15. ..12 55

22

24° 14'

if ^ Bootis

and

forms a

FiGL'Ki; 1. Encke's Comet.

patient search, and it could only be seen on these two
mornings, and then only for a few minutes between its rising
and the dawn. On August 1st it was thought to be of
magnitude seven-and-a-half.

The predicted date of perihelion was 1911, .\ugust 19- 0656.
Berlin M.T. The observation of K.A. indicates that this
should be increased by O"- 178, that of declination by 0''- 128.
Giving the R.A. greater weight, we may take August 19-23 as
a close approximation to the actual date. The error of the
predicted value is larger than Professor Backlund expected :
he notes in Astr. Nticlii:. 4518, that it is not due either to
errors in the computed perturbations or to a wrong mass of
Mercury. Presumably, it arises from an alteration in its rate
of acceleration, which has taken place several times before.
There is a simple way of making pretty accurate forecasts of
the dates of perihelion of this comet bv taking advantage of
the fact that eighteen revolutions of the comet are nearly
equal to five of Jupiter, and consequently the perturbations
nearly repeat themselves after this interval. Table A gives
all the observed perihelion and the interval in days between
each perihelion and the one eighteen revolutions later.

These are plotted in the diagram above (Figure 1) and it
will be seen that they lie on a sinuous curve, from which the
next return (that of 1914) has been predicted. It will probably
not be much more than a day in error. The return of 1911
was predicted from the curve 0-8 days too late. The comet is
most conspicuous at winter returns. Those of 1786, 1795.

401

402

KNOWLEDGE.

Octob!;k. 1911.

1805. 1819 were all winter returns, at all of which the comet
was independently discovered, its periodicity not being detected
till after the 1819 return.

Five revolutions of Jupiter are equal to 21662-94 days.

.M.ARS. — The season for this planet is again coming on.

Phobos. Node 43 •42. 49°-70: Inclination 37--75. 36°-42:
Perimars 251" -0. 213°- 6 : ecc> 0-0205. 0-0068.

It is interesting to compare these results w-ith those deduced
by Dr. Hermann Struve in 1898. He showed that under the
joint influence of the equatorial protuberance of Mars and solar
perturbation the pole of each orbit plane would describe a

1786— Jan. 30-88

1 795— Dc

M-45

IiUtrrval.

21739''-'

21740"-(i

1805— Nov. 21-51

1819— Jan. 27-26
1822— Mav 23-97
1825— Sept. 16- 28
1829— Jan. 9-75
1832— Mav 3-99
1835— .-Vug. 26-37
1838- Dec. 19-02
1842— Apr. 12-03

9

21729"
2 1725'' -3
2 1722'' -4
21719"-2
21716"-()
21712''-4
2 1708'' -8
2 1705'' -4

Perihelion

1845— .-^ug. 9-()l
1848 — Nov. 26-09
1852— Mar.
1855— Jul V
1858- Oct.
1862- Feb.
1865— May
1868— Sept.
1871— Dec.
1875- Apr.
1878— J ulv
1881— No\.
1885— Mar.
1888— June
1891— Oct.
1 895— Feb.
1898— Mav

14-71

1-04
18-37

6-25
27-93
14-62
28-81
1 2 - 99
26-17
15-30

7 ■ 6 +
28- (JO
17-99

4-75
26-8(1

Inter\al.

2 1704'' -3
2 1704'' -8
2 1705'' -5
1 2 1 706'' - 0

Perilwli,

)ii.

1905-

-Ian.

11

88

1 908-

-Apr.

30

91

1911-

-Aug

19

20

(1914-

-Dec

5

-0)

1901— Sept. 15-47

Tahlk a.

53T

The opposition of November, though at a greater distance

than the two last, is favourable on account of the planet's

north declination. Work has already begun ; Professor

Lowell notes that successful photographs of the canals were

taken in August, and that the two canals near Syrtis Major,

announced as new at the last apparition, have again been seen.

M. Jarry Desloges notes Mare Cinnnerimn and Lacus Solis

as pale, while Trivium

Charontis. Mare Sirenuni. Right .Ascension

Titanum Sinus are dark.

He sees many canals.

broad and pale, but easy

to distinguish, in spite

of the planet's distance.

Bathys appears as in 1909.

but quite different from

its 1907 aspect. The

South Polar Cap is very

small. and apparently often

veiled by cloud or mist.

■■ Lowell Bulletin 50 "
contains a determination
of the relative brightness
of Mars' satellites. On
1909, September 16th,
both were seen with aper-
ture reduced to six inches,
and it was estimated that
as regards ease of seeing.
Phobos was intermediate
between Tethys and En-
celadus. When at the
same distance from the
limb, Phobos was con-
sidered to be one and
a-half magnitudes brighter
than Deimos ; the ratio
of diameters is deduced
as two and a-half to
fifteen to one

circle about a fi.xed point which, in the case
of Phobos, is sensibly the same as Mars'
North Pole, but in the case of Deimos is
about 1° distant from it in the direction of the
North Pole of IMars' orbit. The radii of the
circles described by the poles of Deimos and
Phobos are respectively li|° and 1", and the
amount of annual movement about 6-7 and
162'. The perimars of each orbit advances
at a rate sensibly equal to the retrogression
of its pole. The R.A. of the pole of each
orbit is Node —90", and its North Polar
distance is equal to inclination of orbit.
In the diagram P, Pj . . . Pt, D, D-j . . , Dt indicate the
apparent positions of the poles of the orbits at the epochs
1877-7, 1879-8, 1892-6, 1894-7. 1896-9, 1907-5 all reduced
to the eiiuino.x of the last date. H, .i are the fixed points of
the two orbits, according to Struve, ll', A' those revised by the
1907 obser%ation. It will be seen that the alteration is small.
The new positions should not be taken as definitive, since

theorv indicates that H' i'

D, y

N

°'''oN

^.

P. "J .-

' r '
/

P. "^4

a'

■\

iTtr

)

y

%.

^ ''■■'

4^^-^

^"

37"

3«-

l-"iGii-:i; 2.

Diagrams shciwing the positions of the poles of the orliits
of Phobos and Deimos and of the planet Mars.

one, of volumes and masses
There was some evidence of variable bright-
ness on the two sides of Mars, as in the case of Japetus.
A Washington paper has lately appeared containing a
determination of the orbits of these satellites in 1907, by
Professor H. L. Rice. The epoch is 1907. July 0-0, G.M.t!.
and the elements are referred to the earth's ecjuator. In each
element the first value belongs to Deimos, the second to

should be parallel to
II A. II is only 0°-01
Irom the North Pole of
Mars' equator, which is
on the line A it pro-
duced. The diagram also
shows N, the North Pole
of Mars deduced by Pro-
fessor Lowell from his
own observations of the
Polar caps combined with
those of S c h i a p a r e 1 1 i ,
Lohse and CeruUi, and
adopted in the Physical
I-'phemeris in the Nautical
.Almanac. N'. the position
recently given by Lowell
from his own observa-
tions alone, is also shown.
The agreement of N with
II is good in R.A., but
there is a puzzling differ-
ence of 2" in N,P.D.

I think that ultimately
the Satellite method will
pre\ail, for their appar-
ent orbits are nmch larger
than the disc of Mars, and
stellar points can be more
accurately located than a
large patch of irregular shape like the Polar cap. The fact
that the accuracy increases with the apparent size of orbit is
vividly shown by the much wider departures of the points
marked P from the Phobos circle than of those marked D
from the Deimos one. The pole of Deimos' orbit, will have
been observed for a complete revolution about 1931, and
after that the deduced position of the pole of Mars will
probably have nearly reached finality.

(JCTOBER. 1911.

KNOWLEDGE.

403

VAKI.ABLE ST.AKS.— Mr. Joel Stebbins, who lately
detected the secondary niinimuin of Algol with the selenium
photometer, has detected a small variation of light in i^
.•\urigae, a spectroscopic binary, showing that each star
partially eclipses the other in the course of a revolution. The
radius of each component is deduced as 2-6 that of the sun,
the mass of each two and one-third that of the sun. and
density one-third of his. Assuming a parallax of 0"-0J. each
component gives eighty times as much light as the sun at
the same distance, while their intrinsic surface brightness is
twelve times his. According to the diagram given, about one
(luarter of the diameter of each star is covered by the other
at mid-eclipse. Mr. Stebbins has also discovered variability
in 5 Orionis, but his discussion on this is not yet complete.
He proposes to e.xamine other spectroscopic binaries, as,
owing to their close pro.ximity. partial eclipses must occur
in a considerable proportion of them L-Xsfropliys. Joitrn.,
September).

Dr. Ejner Hertzsprung {Astr. Xaclir. 451iSl has detected a
variation in Polaris of 0- 17 magnitude in a period j-96Sl days,
the same as that of its orbital motion given by the spectroscope.
This is not, however, considered to belong to the Algol but to
the Cepheid class, the variation being due to the difi'erent
presentations of an elong.ited spheroid.

BOTANY.

By Professor F. C.weks, D.Sc, F.L.S.

BOTANY AT THE HKITISH ASSOCIATION.— The
meetings of Section K (Botany I at Portsmouth this year were
of unusual interest owing to the presence of a large contingent
of Continental and .American botanists. During the four
weeks preceding the commencement of the Portsmouth meet-
ing these distinguished visitors, along with a number of
British botanists, had made an extensive tour of this country,
specially arranged for them by the International Phyto-
geographical Excursion Committee.

.\s might have been expected in the circumstances, l-^colugy
formed an outstanding feature of the meetings, perhaps to the
exclusion of other departments of Botany, so that the papers
read were not quite so representative as usual of the science
as a whole. Two entire days were devoted to Ecology, and
several ecological papers were also given on the other days.

PRESIDENT! AL ADDRESS.— In his Presidential Address
to the Section, Professor F. E. Weiss, of Manchester Univer-
sity, devoted himself mainly to the consideration of certain
problems in Fossil Botany, not omitting that attractive phase
of the subject, the Ecology of fossil plants. He pointed out
that the possibilities of vegetable fossils preserved only as
inipressioits in the rocks had been practically exhausted in
1870, when Sachs published his fascinating History of Botany,
and dwelt upon the debt which botanists owe to the pioneers
of modern Palaeobotany — Binney, Williamson, Renault, and
others — who first show-ed that the structure of fossil plants is
in certain cases preserved in the most remarkable manner by
petrifaction and can be studied in microscopic preparations as
effectively as has been the case with recent plants since the
days of Grew and Malpighi.

After dealing with the (luestion of the homology of the well-
known Stigiuaria, and reviewing the various explanations that
have been put forward regarding the nature of the Stigmarian
axis and its appendages. Professor Weiss concluded that
various recent observations strongly support Williamson's
view that Stigniaria was a down-growing prolongation of the
stem of the Lcpitlodeitdron and Sigillaria to which it
belonged, corresponding to the lower part of the stem of the
present-day plant Isoi'tcs, the Stigmarian appendages answer-
ing to the roots given off by this portion of the plant in Isoctcs.
Apparently the one thing now lacking to complete the chain of
evidence in favour of Williamson's theory is the discovery of
tips of Stigiuaria rootlets showing structure.

Passing onto the remarkable Pteridosperms, which combine

the characters of Ferns and Cycads, Professor Weiss called
attention to the criticisms which Chodat has recently put
forward a.gainst the too wholesale acceptance of the view that
these seed-bearing, yet fern-like, plants form the " missing
link" between Ferns and Cycads. .According to Chodat the
stem of a typical Pteridosperm like Lyginudendrou presents
purely fern-like characters in its structure, contending that the
bundles of primary wood are not " mesarch," like the leaf-
bundles of C\-cads, but have only centrifugal wood ; while the
presence of secondary growth in thickness is no indication of
Cycad affinity, but is merely comparable to what is found in
various other fossil Ferns and Fern-allies. Chodat regards the
"seed" of Lyginodcndron as being merely a specialised
development of the megaspore, corresponding to the seed-like
organ found in the extinct Lycopod genus Lepidocarpon, and
considers that the origin and the biology of this kind of ""seed"
must have been \ery difterent from those of the seeds of the
Gymnosperms. In bringing forward Chodat's views, which
run counter to those generally accepted in this country,
on the nature of the Pteridosperms as the result of the brilliant
discoveries of Oliver and Scott, Professor Weiss disclaimed
any desire to urge their acceptance, but considered that
Chodat's criticisms are sufficiently weighty to demand careful
reinvestigation of the structure of some of the Pteridosperms,

Professor Weiss proceeded to make some criticisms of his
own regarding recent theories on the origin of the .^ngiospernis
from the Meso^oic group Bennettitales, pointing out that some
botanists have " exceeded the speed-limit " in too rapid
formulation and acceptance of such theories, and expressing
his desire " to walk circumspectly in the very alluring paths
by which they have sought to explore the primaeval forest,
and not to emulate those rapid but hazardous flights which
have become so fashionable of late."

In the latter part of his address, Professor Weiss dealt with
the biology and ecology of fossil plants, a wide and promising
field of research, of w hich only the fringe has yet been touched.
Since the remains of plants are sometimes continuous through
adjacent coal-balls ("calcareous nodules"! it is clear that
these concretions were mainly formed (';; situ, and that the
plant remains they contain represent samples of the vegetable
debris of which the coal-seam consists, giving us an epitome
of the vegetation existing in Palaeozoic times on the area
occupied by the coal-seam; while the Stigmarian rootlets in
the underclay help to prove that the seam usually represents
the remains of the Coal Measure forest carbonised //( situ.
This raises the question : What were the physical and climatic
conditions of these primaeval forests ? The structure of the
roots of Calamites. Lepidodendra. and so on, with their large
air-spaces, leads us to believe that, like many of their existing
relatives, these plants were rooted under water or in water-
logged soil ; while the narrowness and the xerophilous
structure of the leaves of these plants closely resembles the
modifications met with in our marsh plants. None of the
living Equisetales or Lycopodiales — the groups to which
belong the Cal.amites, Lepidodendrons. and Sigillarias of the
Coal Period — grow in salt marshes. Nor is it necessary to
invoke the salinity of the marsh to explain the good preserva-
tion of the tissues of the plant remains, in \'iew of the well-
known power of humic substances to retard decay of vegetable
tissues. Again, certain fungi found as parasites in coal
plants seem to support the fresh-water nature of the swamp,
just as the occurrence of a mycorhiza or " fungus servant "
in some coal plants seems to indicate the presence of a peaty
substratum. In some cases, millipedes and fresh-water shells
occur in the Coal Measures among the plants ; and the possible
presence of marine organisms may be accounted for by
occasional invasions of the Coal Measure swamps by the sea,
especially as these swamps may well have been estuarine or
formed near the sea.

Since so many types of vegetation are found in the Coal
Measures, it is somewhat difficult to explain the occurrence,
side by side, of land-plants and marsh-plants, though in certain
cases it is clear that the remains of land-plants were carried
into the swamp after its submergence below the sea. However,
we can at the present day trace the gradual development of a

404

KNOWLEDGE.

OCTOUER, 1911

lake type of vegetation from the reed-swamp through the
marsh type to the peat-moor type, noting how one plant
association makes place in its turn for another. Possibly the
mixture of various types of vegetation found in coal-seams
represents the transition from the open Calamitean or
Lepidodendroid swamp to a fen or marsh with plentiful
peat-formation, due to the gradual filling up of the stagnant
water with plant-remains. In this transition from acjuatic to
more terrestrial types of vegetation, the tree-like forms rooted
in the deeper water would continue to flourish, while there
would be a luxuriant undergrowth of Ferns and Pteridosperms
— this undergrowth being placed in excellent conditions owing
to the narrow-leaved nature of the canopy of trees under
which it grew, apart from the provision of a suitable sub-
stratum for its roots. This would explain the striking
difference between the narrow-leaved tall Calamites and
Lepidodendraceae, and the large-leaved Ferns and Pterido-
sperms. which spread out their foliage from short stems
under the shade of the former.

CHEMLSTRV.

By C. AixswoKTH MrrcHKi.r,. H..\. KJxox.l. F.l.C.

DISTRIBUTION OF SLciAK IN THE BEFT KOOT.
— The distribution of sugar and non-sugar substances in the
beet root has considerable importance, both from the point of
view of vegetable physiology and of sampling for connnercial
purposes. Some work has ah'eady been done in this direction,
but in the opinion of Messrs. Floderer and Herke {Zcit.
Ziickcrind. u. Laiulw., 1911. XL. J85) its accuracy is open
to question, owing to the defectise methods of dividing the
roots for the analysis. .Accordingly, they have made a fresh
investigation, using for the purpose fifty roots of uniform size,
which they divided into ten transverse sections and sub-divided
into concentric rings in the manner shown in the diagram.
The respective corresponding pieces from each of the roots
were mixed together so that in all nineteen separate lots were
obtained for the analysis.

The results showed that the sugar (sucrose) was present in
the greatest proportion in the innermost portion of the root,
those sections between the middle axis and
the part where the root began to taper
being the richest. Thus the most sugar
was found in the following sections, 14, 15,
19, 13, 12, IS. 17 and 16; and then in
decreasing quantities in 11, 6, 8, 5, 4, 3,
7. 9, 2, 10 and 1. Whence it appears that
the body of the root is richest in sugar
and the crown the poorest.

With regard to the other constituents it
was found that the total solid substances
varied but little in any part of the root,
with the result that a rise in the proportion
of sugar was accompanied by a decrease
in the amount of non-sugar substances.
In fresh beet roots the proportion of soluble
nitrogenous bodies was lower in the interior
parts, while the mineral constituents (ash)
varied inversely with the amount of sugar.
A decrease in the amounts of potash and
magnesia was observed on proceeding from
1 down to 15. where the sugar was present
in greatest proportion, after which both
substances increased with the fall in tlie
sugar. It was not possible, however, to establish any re-
lationship between the amounts of sugar and phosphoric acid.

"NON-INFLAMMABLE" 1 LANNELETTE. — Tin-
Power Laundry, of August. 1911, publishes the results of
an investigation of the alleged non-inflannnability of various
kinds of flannelette on the market, which has recently been
made in The Lancet laboratory.

In the case of some of the samples of material examined,
the claim of non-inflammability was an obvious fraud, but in

FlGLKK 1.

A diagram illus-
trating the distri-
bution of Sugar
in the Beet-root.

others the problem had been solved by loading the fabric
with mineral salts. One of the principal dangers of
flannelette is the tendenc\- of the fine loose fluff, which becomes
detached from the fibres, to flare up on contact with a flame.
This tendency has been greatly reduced in certain products
by weaving the fabrics with a much finer mesh, but it would
seem that this only affords partial protection, and the risk of
their catching fire increases after every washing.

Even in the case of materials rendered fireproof with
mineral salts, a large proportion of the ash is washed out, and
this may be sufficient to render the washed fabric unsafe.
It is interesting to note, however, that in the opinion of The
I^aiicet chemist, a definite compound appears to be formed
between the cellulose and the mineral compound — apparently
a salt of tin. This would explain the retention of a high pro-
portion of the mineral constitutents even after repeated
washings with soap and water.

The results obtained with twelve specimens of typical com-
mercial flannelette and the conclusions drawn from them, are
summarised in the following table . —

Oiii;in;iI

.Ash after

Percentage

Percentage of

I'ubiic.

.\bh.

w.-ibhiili;.

of Residual

Ash vvashecl

Conclusion.

Per cent.

Per cent.

.Ash.

out.

A

5-61

0-21

3-75

96-25

L'lisafu

B

2-41

0-18

7-50

92-50

.,

C

2-18

0-81

37-16

62-84

Doubtful 1

Dl

11-49

9-83

85-86

14-44

Safe

D2

11-69

7-66

65-53

34-47

)'

D3

12-49

9 -(JO

72-00

28-00

D4

18-73

8-86

47-30

52-70

^^

D6

20-77

17-50

84-26

15-74

»1

D7

21-35

15-15

70-20

29-80

.,

E

0-68

0-52

76-50

23-50

Fl

8-86

0-20

4-50

95-50

Unsafe

F_'

1 -87

A';7

A'/7

100-00

The reduction in inflannnability corresponded with the
increase of mineral matter, the samples " D6 " and "1)7,"
for instance, being the most resistant of all. .Although fabrics
treated with a sufficient proportion of suitable salts may thus
be rendered fireproof, yet the (juestion arises whether the
natural properties of the cotton fibre may not be impaired by
the presence of as much as a fifth part of mineral matter in the
fabric, e\en though it is in combination with the cellulose.
One point that is brought into prominence by this insestiga-
tion is the imsatisfactory state of the law. which permits
highly imflammable material to be sold at a higher price under
the description " non-inflammable," and thus lulls the pur-
chaser into a ccjndition of false security. So far from
reducing the death rate from this cause the sale of much of
the " non-inflammable " flannelette on the market appears to
ha\'e led to an increase nf fatalities.

("xEOLOGY.

By (i. W. TVRKKI.I,, A.R.C.Sc, F.G.S.

THE FLOWING WELLS OF CENTRAL
AUSTRALIA.— A paper by Professor J. W. (jregory, F.K.S..
in the July and August numbers of The Geographical Journal.
renews interest in these remarkable wells. This paper is by
way of answer to the strictures of Mr. E. Pittnian and others
on Professor Gregory's views on the subject, as expressed in
his book "The Dead Heart of Australia." In the latter he
criticised the wasteful methods of utilizing the water from
the wells, and combated the current view as to the origin of
the supply, by w-hich this wastefulness was excused. The
water ranges through an area of some five hundred and eighty
thousand square miles in Central Australia. The general
view is that it is derived from the Eastern Highlands of
Australia, and is continually replenished by percolation
into water-bearing beds, from rainfall and rivers in fb;it

OcTnHi:R. 1911

KNOWLEDGE.

405

region. The wasteful methods of use are justified ou the
.ground tliat the replenishment so greatly exceeds the flow
that the loss of water is unimportant. After a careful
examination of the available evidence, Professor Gregory
entirely rejects the view that the wells are supplied by
rainfall, and are, in fact, of the normal artesian type. He
holds that the water is derived from three main sources :
(1) plutonic wafer from the interior of the earth ; (2) residual
water enclosed in the rocks at the time of their formation :
13) rainfall which percolated into the sandstones at an earlier
geological period. If this is the case the supply is not
unlimited.' as is maintained by those who support the older
theory, and a diminution of yield is to be expected ; so much
so that in the near future pumping may have to be resorted
to in order to keep up the supply. .-Vccording to Professor
Gregory, this diminution has already begun in most parts of
yueensland. South .Australia and Xew South Wales.

The question is obviously of vast importance to Australia.
If Professor Gregorv's Views are correct, the present waste
is deplorable, and should be stopped as soon as possible.
Fortunately, if it does become necessary to resort to pumping,
the waste of water will be much lessened, and the decline of
the water-level will become correspondingly slower.

PORPHYKITIC MONCHIOUITES IX BRITAIN.—
Several very typical monchiquites have now been described
from these islands, especially from Scotland. The monchi-
quites are characterised by their abundance of ferro-magnesian
minerals, their groundmass of analcite, and fretjuently by the
presence of remarkable ocelli, composed of radially arranged
augite prisms surrounding a nucleus of analcite. .A remark-
able variety has recently been described by Professor \V. S.
Boulton, in a communication to the Geological Society, This
rock is intrusive into the Old Red Sandstone of Monmouthshire,
between Chepstow and L'sk, and contains huge phenocrysts,
attaining five or six inches in size, of augite and biotite.
Xodules of olivine-augite rock are also described. This
rock is compared with the monchiquites of Colonsay and
Argyllshire. It is remarkably similar to a dyke-rock from
Kilchattan in Colonsay, which carries enormous crystals of
hornblende, biotite and augite. This rock, described in the
Summary of Progress of the Geological Survey for 1909,
page 52, is distinguished by containing nepheline, thus belong-
ing to the rare group of nepheline-monchiqnite. The writer
of this column has discovered a third example of porphyritic
monchiquite in .Ayrshire. It occurs as part of an intricate
complex intruding the agglomerate of a volcanic rock of Late
Palaeozoic ("Permian") age, at Carskeoch Hill, near Patna.
This rock carries huge phenocrysts of red barkevicitic horn-
blende, and biotite. Purple augite and olivine occur as a
second and smaller generation of phenocrysts in the usual
monchiquitic groundmass. The rock forms part of a complex
in which, teschenite, teschenite-picrite, essexite, and a new
ijolitic rock containing much analcite, also occur. The age of
this monchiquite is definitely fixed by its mode of occurrence.
It belongs to the widespread suite of alkaline igneous rocks of
Late Palaeozoic age so abundant in the West of Scotland.
The .Argyll, Mull and Colonsay examples are believed to be of
Tertiary age, but may well be older. They have the usual
north-west trend of the Tertiary suite, and cut the east-west
dykes of quartz-dolerite which are of Late Carboniferous age.
The Monmouthshire occurrence is at least post-Old Red
Sandstone, and it is noteworthy that it is regarded either as a
d\ke with a north-westerly trend or as a volcanic plug.
Another significant point is that the only other intrusion into
the Old Red Sandstone of this district, that of Bartestree, near
Hereford, has been described by Professor S. H. Reynolds, as
teschenite, an analcite-bearing dolerite.

METEOROLOGY.

By John A. Curtis. F.R.Met.Soc.

The weather of the week ended August 19th, as set out in
the " Weekly Weather Report " issued by the Meteorological
Office, was very fine generally, though thunderstorms were

reported on the 13th and 19th. Temperature was above the
a\'erage in all districts, the departures from the mean rising to
7'-S in England, S.W. The highest readings were 92 at
Tottenham, Cambridge, Raunds and Bath, on the 13th. In
the extreme Xorth it was much cooler, and at Baltasound and
Lerwick the maximum for the week was only 60°, In the

West the heat was not excessive, the r^ • • -n at Scilly being

76, and at Falmouth 74^\ The 1o\m i ngs were 37° at

Balmoral and at West Liiiton, and J'/ <xi .\arin and Wick.
These were the only stations with minima below 40' ; at manv
stations the minimum was not below 50', and at some stations
not below 60^. The temperature on the grass fell to 32° at
Llangammarch Wells and to 35° at Crathes.

Rainfall was greatly in defect everywhere, except in London,
where it was slightly above the normal. At many stations the
week was rainless.

Bright sunshine was in excess of the average except in
Scotland, E., where it was normal. In p'ngland. X.W., it was
twice as much as usual. 72 hours (70%). while in England.
S.E., the value was still higher, 77 hours (76%). The highest
individual amounts reported were 88-9 hours (88%) at Brighton.
85-1 hours (84%) at Hastings, and 84-7 hours (84%) at
Eastbourne.

The temperature of the sea water round the costs ranged
from 54° at Lerwick to 72° at Margate.

The week ended August 26th was unsettled all over the
country. Rain fell on se\'eral days and tlnniderstorms were
experienced in almost all parts.

Temperature was still high, however, though the excess
abo\"e the average was nowhere so great as in the preceding
week. The highest readings were 85° at Wisley. and 85 at
Cambridge and Raunds. In Scotland the maximum was only
73°. while in Ireland, at Killarney, it was 74°.

The lowest readings were 35^ at Balmoral, and 36° at
Markree Castle, Co. Sligo. At Westminster the temperature
ranged between 56' and 81°. On the grass, however, frost
was observed, the readings falling to 30° .at Markree. and to
52' at Balmoral and at Llangammarch.

The rainfall varied a good deal. It was slightly above tbe
average in Scotland, X., the Midland Counties, and England,
S.E., and considerably above in England. X.E. In all other
districts it was in defect. At several stations falls exceeding
an inch in 24 hours were reported ; at Portsmouth the amount
on the 21st was 1-40 inches, 1-00 of which fell in half-an-
hour.

Bright sunshine was in defect in all the Eastern Districts,
and in excess in the Western parts. The most sunny district
was the English Channel with 48 hours (49 %) and the sunniest
stations were Guernsey 55 -7 hours (57%) and Pembroke 55-1
hours (56 %).

The niean temperature of the sea water ranged from 54 ■ 8°
at Berwick to 68-5° at Margate.

The week ended September 2nd. was fine as a whole, but
in Scotland and the Xorth of England rain fell rather
frequentl>'. Thunderstorms occurred at various stations
during the earlier part of the week. Temperature was still
high, the excess above average in England, E., amounting to
more than 5^. The highest readings were 90° at Camden
Sc|uare. Cromer and Hillington. with 89° at Greenwich,
Cambridge and Xorwich. The lowest readings were 34°
at Marlborough, and 37° at Nairn and Balmoral. On the
grass the temperature fell to 30° at Cnithes and to 28° at
Llangammarch.

Rainfall was in defect in all Districts except Scotland, N..
and Scotland, W. .At Glencarron the total fall for the week
was 3-61 inches, and at Fort Wilham 4-16 inches, which in
each case was more than twice the average.

Bright sunshine was in excess in all the Districts, the
district means \-arying from 40 hours. (40%! in Scotland, X„
to 62 hours (65 %) in the English Channel. The sunniest
station was Jersey, 69-8 hours (74%). .At Westminster the
total duration for the week was 54-9 hours (58%).

The temperature of the sea water varied from 53° at
Scarborough, to 70° at Margate.

406

KNOWLEDGE.

OcTOBru. 1911.

almost iici;lii,'ible.
in Sciitland. N."

The weather of the week ended September 9th was \er\-
fine and dry tfeneralK-, bnt with thnnderstorms on the 4th
and Sth. Temperature was again above the average, the
excess in most parts of England being large, as much as 7^' 8
in England, S.W., and 9°-3 in the English Channel. The
highest readings were again \er\- high. o\er 90 in man\'
cases, and reaching 93" at Bath and Cambridge and 94° at
Greenwich and Kannds. In the extreme North, however, the
temperature was low ; at Lerwick the maximum was onl\- 59".
The lowest readings were 31° at West Linton, .ind M" at
Balmoral. ( )u the grass the temperature was \er\ low for
the time of ye.ir, falling to 26° at Llanganmiareh. 27° at
Crathes. and 30' at Balmoral and Colmoni'll.

Rainfall was again greatly deficient in all district:
except in Scotland, N,, the total fall was
At many stations the week was rainless.

Bright sunshine was in excess except
where it was just below the normal. The district means
varied from 25 hours (26%) in Scotland. \'.. to 68 hours 173%)
in Ireland. S. The sunniest stations werre X'alencia 78-1
hours I84",>), Jersev 77 -J hours (84%) and Terdn- 74-9 hours
(81%).

The mean temperature of the sea water varied from 54° '0
at Lerwick to 68° -0 at Eastbourne,

The \\ eek ended September 16th. was cooler and less settled
than tlinsc inunediately preceding it. with thunderstorms on
tile 1 Uli and 12th. Temperature in many parts differed but
little from the average, but in the Southern districts it was
still above the normal. The highest readings were 88° at
Greenwich. 87° at Margate and Tunbridge Wells, and 86° at
Westminster. Cambridge and Geldeston. The minima fell
below the freezing point on the 16th. to 31° at Colmonell. and
to 28° at Llangammarch Wells. On the same day ii° was
recorded at Hereford, while on the 13th the minimum at
Balmoral was i2°. On the grass, temperature fell very low . to
14 .it Llangammarch, 22° .it Hereford and 27 at Colmonell.

Rainfall was considerably in excess in England, X.W., where
it was more than double the average. In Scotland. N., it was
drv. and only one-third of the usual amount was collected.

Bright sunshine exceeded the average, except in Scotland \i.
and in Ireland, the excess in England S.E. exceeding two
hours per day. The sunniest stations were Eastbourne
59-5 hours (67%), Hastings 58-8 hours, (66%), and Guernsey
58-9 hours (66%). At Westminster the total duration was
48-3 hours (54%).

The temperature of the sea water was as low ;is 49 at
Scarborough, and rose to 68" at Margate and at the Shi])-
wash Lightship.

MICROSCOPY.

By A. W. Sheppard, F.R.M.S.,
iii'itli tlic iissistiiiicc of the foUoti'ing iiiicroscopists : —

,\r1HUR C. BaN'FIELO. .\RTHUR I'^ARLAND, F.R.M.S.

The Rev. E. W. Bowei.i., M.A. Richard T. Lewis. F.R.M.S.

James Burton. Chas F. Roussei.et. F.R.M.S

Charles H. Caffvn. D. J. Scourkieli>, F.Z.S., F.R.M.S.

C. D. Soar, F.I..S.. F.R.M.S.

MACROSl'OI'UL'M (FRIES).— The large compound spores
of this fungus form handsome micro-objects, even for low
powers, and are by no means difficult to obtain, especially in
the autumn. The genus contains both saprophytic and
parasitic species, though there is much doubt as to their
exact limitations, .Some are found growing on decaying
cabbage leaves, bean pods and other vegetable refuse ; a fine
species M. sarciniila (Figure 1) is not at all uncommon on
over-ripe melons, where it appears as black velvety patches,
sometimes of considerable extent. It would be difficult,
perhaps, to decide in many cases whether the fungus is a
saprophyte or a true parasite. Another example, more
fre<)uent than welcome, is well-known to growers of tomatoes.
It occurs both on the plant and on the fruit, but chiefly on

the latter, and anyone wishing to obtain specimens for
examination should look over some poor samples, when
the parasite — as it almost certainly is in this case — will
be found as black or olive-green patches of various sizes,
usually sunk a little below the general surface. On cutting a
thin slice from the region, it will be discovered that the
underlying tissue is permeated by the somewhat coarse thread-
like mycelium of the fungus, and occasionally the spores are
developed in this situation. One species, named M. solnni.
attacks potatoes and may do much damage, particularly to
the foliage and stems, though it also attacks the tubers, and
may be transmitted, by means of the "seed" (dormant budsl
used for planting, to a subsequent crop. This is now believed
bv competent authorities to be the same species as that found
on tomatoes, M. tomato (Cooke), which appears likely, as the
hosts are so closely related. There is a great similarity
between all the species of the genus ; the vegetative body
consists of a web of mycelium ramifying in the substratum,
but usually not very large in amount ; this approaches
the smface and there throws up short, jointed, mostly simple
stems, which bear the large many septate spores. These vary
a good deal in shape and size within the same species, and

I'IGIIRK 1.

FiGliRK 2.

each division — which is in effect a distinct spore — ina\- under
favourable circumstances put out a tube (hypha) which gives
rise to a new fungus plant. An interesting experiment may
easily be made with the tomato species. If some of the spores
are placed on a fruit with uninjured cuticle, it will be found
they are unable to penetrate it ; but if a wound is made or
they are placed on a cut surface, they quickly germinate and
in a short time a fresh crop of the fungus and a plentiful
supply of spores is obtained. It is necessary to keep the host
in a suitable condition of warmth and moisture, which may be
achieved by placing it in a saucer with a little water, covered
by a tumbler, in a warm situation. The experiment illustrates
the danger of infection through abrasions of the resisting
outer surface, by what are known as " wound-parasites."
Some of the species are known to be the conidia-
bearing stage of an ascomycetous fungus. Dr. Cooke says that
such is the case with M. sarcinula, and that it is a condition
of the common little fungus Sphitcria licrbaniiii. which is
plentiful on various herbaceous plants, and looks — under
moderate magnification — like little black wine flagons.
Figure 1 is a representation of M. sarciiiitht. In Figure 2a
.are seen the spores of a species which was found growing
inside a Tangerine orange. The hyphae appeared to be unable
to emerge through the thick peel, but when a part of this
was removed, the spores were produced in great quantity. .A.t
b is figured an example of M. toiiiato. on the right hand are
shown some spores commencing to germinate. .At c part of a
spore is represented emitting a mycelium tube from nearly
every division and is taken from Professor Massee's " Text
Book of Plant Diseases." The species is M. iinhilc. which
occurs on carnations. , „

NOTE.— The figure of .-Xnabaena — " Knowledge," Sep-
tember, page 354 — was unfortunately wrongly placed. To agree
with the text it shovild be turned till the part towards the North
is at the South-east. J. B.

October, 1411.

KNOWLEDGE.

407

Figure 1. A Feacli branch

attacked by peach curl, Exoascits

dcfoniians.

l-lc.L Kl. 2. Vcilital Mcliiiii >A a

leaf of Peach infected with Exoascits

dcfonnans, X 500.

EXOASCLS DEFORMANS BERK.
(PEACH CURL).— This fungus is the
cause of a remarkable disease in Peach
trees often proving fatal to young stock.
Although the mycelium is perennial in the
branches, the disease first becomes evident
in early spring when the trees are producing
their first leaves. Many of the leaves are
at once virulently attacked and as a result
they assume the remarkably thickened and
curled appearance as seen in the first
photograph. In colour they are yellowish-
green splashed with red, probably due to
the decomposition of the chlorophyll. As
a consequence of this, photosynthesis is
inhibited, resulting in a poor development
of the plant. .After a period of vegetation
the fungus reproduces itself asexually. On
certain localised areas of the leaf minute
club-shaped bodies appear. These organs
are asci, a reproductive structure typical of
the large order of fungi — the Ascomycetes —
of which Exuasciis is the simplest represen-
tative. The contents of each ascus di\'ides
to form eight spores — ascospores, which
again undergo division resulting in the
formation of a large number of minute spores
(see photograph) which on liberation carry
on the work of destruction. Owing to the
fact that the mycelium is perennial the
disease is not easily eradicated. The usual
method adopted by the nurseryman is the
picking off and burning of all infected
leaves.

CYSTOPUS CANDIDUS PERS.
(WHITE RUST) ON CAPSELLA
BURSA PASTORIS (SHEPHERD'S
Pl'RSE). — Figure 3. Cystopus candidns
is an interesting member of the Oiimycetes,
a sub-class of the Phycomycetes or algal
fungi — a name given to the group on account
of the structure of the se.xual organs, which
are strikingly similar to those of the
Siphonae, of which N'aucheria is an
e.xcellent type. The Phycomycetes arc
considered to be derived from the Siphonae.

The white patches well seen in the
photograph are the sporangia of the fungus,
the structure of which is demonstrated in
Figure 4. The mycelium ramifies through-
out the tissues of the stem, leaf and fruit,
and eventually breaks through the epidermis
giving rise to pustules of sporangia. These
sporangia are produced in chains and on
germination give rise to numerous swarm
spores, which, given moist conditions,
rapidly infect neighbouring plants. The
sexual organs are antheridia and oiigonia
— arising icitliin the host plant. The
oiigonia are spherical swellings fonned at
the ends of the hyphae, or intercalated
throughout their length. The contents of
the oogonium become differentiated into
an oospore and peripheral periplasm. The
antheridia are tubular outgrowths, cut off
from the parent hypha by a cell wall.
.\fter fertilisation the oospore surrounds
itself with a thick wall of a brownish
colour, the surface of which is covered
with irregular warts. After a period of
rest the oospores germinate. In the hard
spore walls a fissure appears, and the
contents of the spore, surrounded bv
the inner membrane, are pressed through
the orifice. The protoplasm divides

FlGURli 3. Stems of Shepherd's

Purse attacked by white rust,

Cysfupiis caiididns.

IGUKl-J 4

IGUKl-J 4. \ I itiial secticin nt tlic
stem of Shepherd's Pur.se infected
with ('vstnbiis Ccliulidn ■ ^ ■""'

item ot Shepherd s Pur.se mtectei
witli Cystottiis ciiiultdiis, X 200.

40S

KNOWLEDGE.

October, 1911.

into a number of zoospores, which are Uberated by the
dissolution of the membrane. H. GUNNEKV.

QUARTERLY JOURXAL OF MICROSCOPICAL

SCIHXCE.~ln the August number (\'ol. V, Part 1) of the
above journal there are one or two papers which may be of
interest to our readers. The first to which we would draw
attention is the interesting paper by Dr. W. E. A^>ar. devoted
to the Spermatogenesis of Lcpidosircn paradoxa. In the
course of the research most attention was paid to the method
by which the numerical reduction of the chromosomes takes
place — owing to its importance in connecting the experimental
l^nowledge of heredity with the structure and history of the germ
cells. The sections of the testes for examination were mounted
between two cover-slips instead of between cover-slip and slide.
This allowed of the nuclei being examined and drawn from
both sides. The advantages of this method are well shown in
one of the beautiful plates illustrating this paper, where two
figures of the same section are given, but drawn from opposite
sides. The other paper we would draw attention to is by
C. H. Martin, M,A., and Muriel Robertson, M..-\., under the
title of " Further Observations on the Caecal Parasites of
Fowls, with some reference to the Rectal Fauna of other
\"ertebrates." Four new species are described and figured : —
Chiloinastix naUinaniin. Triclioiiioitas gaUinannit. T.
chcrthi. Trichoiiiastix gallinciniiii. The authors say that
until the whole life-cycle of these animals are known the break-
mg-up of the complex series of forms inhabiting the caeca of
fowls into good species is a matter of great difficulty. The
Trichomonas affinities of these forms were disregarded by
Saville Kent (Manual of Infusoria, 18S1), who named them
Trypanosoma cbcrthi. The plates illustrating this paper are
deserving'of very high praise. They show the nuclear changes
that take place during di\ision and the forni.ition and develnp-
ment of the flagella.

MICROSCOPY IX THE XICW •■ENCYCLOPAEDIA
BRITANNICA." — The article devoted to the Microscope in
previous editions of the '" Encyclopaedia Britannica " now
gives place to one by Dr. Otto Henker. The author first
deals with the different forms of the simple Microscope and
the optical theory relating to the use of a simple lens as a
magnifier. The Compound Instrument is dealt with more
fully. A short history precedes the more detailed treatment
of the physical theory of the instrument, the diffraction
problems underlying Abbe's theory of microscopic vision
being fully explained and illustrated. .\ short paragraph is
devoted to ultra-microscopy. The illuminating systems are
next treated and here mention is made of some old
methods revived for the production of dark field illumination.
Special attention is here given to Siedentopf's Cardinid
Condenser for use in this form of illumination. The
various methods of obtaining binocular vision with the
microscope are explained, and a section is devoted to
mechanical arrangements under which heading Micrometry
is dealt with. The article concludes with the methods of
testing the instrument.

A special article is devoted to Microtomy by C H. I'"owler,
Ph.D., F"',L.S., F.Z.S., and this appears to be the only one
having micro-technique for its subject. In it we have the
theory of staining and the methods adopted for cutting
sections and ribbon-sections. For Photomicrography we
have to look under Metallography, where the method of
obtaining photographs of the surface of metals is given.
This subject has assumed such importance of late years that
an article devoted to its methods would have been better than
relegating it to the heading Metallography, which, of course,
is but ope of its many applications. The preparation of
rock-sections and their examination by means of the micro-
polariscope is fully and clearly explained under the heading of
Petrology. This account of micro-techniciue, as applied to the
examination of rock-sections, is excellent, .-Xttention is drawn
to the further refinement of microscopical method, consisting
in the use of strongly convergent polarized light (konoscopic
methodsl. This is obtained by using a wide-angled achromatic
condenser above the polariser and a high-power microscopic
objective.

(3RNITHOLOGY.

By Hugh Bovu Watt, M.B.O.U.

BITTERN NESTING IN ENGLAND.~The belief
that the Bittern [Botaiirus sfcUaris). if given fair opportunity,
would resume breeding in England has, happily, been substan-
tiated this season. Miss E, L, Turner, when in Norfolk in
July, was so fortunate as to assist in finding a young bird
which she considered to be from four to five weeks old, and
the Rev. M. C. H. Bird, in the course of a joint search,
discovered the vacated nest. From its condition Miss Turner
judges that more than one inmate must have been successfully
reared. She gives a detailed account of her experiences in
Britisli Birds (September, 1911, pages 90-97), illustrated by
photographs of the young bird and the nest.

The last eggs discovered in Norfolk were at L'pton, near
Acle, in 1,S6S, and a young bird was killed at Reedham in
August, 1SS6. Since then, although Bitterns ha\e not
infrequently appeared near their old nesting-places, they have
not managed to breed. It seems not much more than a
counsel of hope to wish that this bird may now re-establish
itself as a regular nesting species, however greatly this is
desired by bird-lovers.

BIRDS NEW TO SCOTLAND IN 1910.— The excellent
and full reports on Scottish ornithology appearing annually in
the Annals of Scottisli Natural History are indicative of
the enthusiasm with which bird-study is pursued in Scotland,
and of the fresh discoveries and good results which reward the
observers. In the July number of the Annals (No. 79, pages
1J3-149) the first instalment of the Report for 1910 is given
by Misses E, V, Baxter and L. J. Rintoul, who draw attention
to the innnber of species and sub-species added to the Scottish
list during the year. These are eleven in all, and are as
follows : —

L Rock-thrush {Monticola saxitilis). One adult male:
Pcntland .Skerries ; Orkney, 17th May. Second occur-
rence of species in Britain.

2. Blyth's Reed-warbler iAcroccpluil ns di(iiuiiti>nini\.

One: F"airlsle; September. First record for Western
Europe.

3. Marsh Warbler (.4. palnstns). One; St. Kilda ;

autumn. First time in Scotland.

4. Temminck's Grasshopper, or the Lanceolated Warbler

iLocustclla lanccolata). One; Pentland Skerries;
26th (October. F'irst record for Scotland and second
for Britain.

5. American Pipit iAntlias spinolctta pcnsilvanicaK

One : St. Kilda ; autumn. New to Britain. Only two
other European records.

6. Hoary Redpoll iAcantliis horneinannii cxilipcst Fair

Isle, no data given. F'irst record for Scotland.

7. HolboU's Redpoll iA. linaria holhocllii). Occurred in

some numbers in different places in eastern Scotland.
.s. ^'ellowshank [Totanns ttavipcs). One; F'air Isle; no

data given. F'irst record for .Scotland.
The imdernanicd are continental forms of birds of which
there are British sub-species.

1. Redbreast [Eritaciis riihccnia riil)cciila). One ; Isle

of May; 2ind October.

2. Goldcrest [Regains rcgnlns rcgidnsK Seven; Isle of

May; between 10th September and 17th October.

3. Great Tit [Parns major major). One: Isle of May;

15th October, .\nother; F'air Isle; 17th No\ember.

A'o^c-. — The first Scottish records of the Continental Song-
Thrush iTnrdns philomclos pliiloniclos^ and the
northern Willow Warbler tPhylloscopns trochilas
cversmanni) came both from the Isle of Ma\'. in
the year 1909.
It will be noticed that practically all these new records are
obtained from islands, an illustration of the importance of
such outposts as bird-observatories, when watched with
vigilance, carefulness and continuity. The records of Heligo-
land bv Giitke are still unri\ ailed.

October, 1911.

KNOWLEDGE.

409

GROUSE AND DISEASE.— Supplementing the note on
page J55 ante, it should perhaps be said that Dr. Shipley, in
the Report, explains that in the course of their researches
during the inc|uiry, the investigators did not come across the
"disease," which is so firmly believed in by sportsmen and
gamekeepers. Twenty-three parasites of the grouse were
found, and Dr. Slnplc\- writes of the worm Tricliosti'ongylns
pcrgrcTcilis as follows: — "The eggs give rise to larvae in about
two da\'s. The larvae surround themsehes about the eighth
day with a capsule or cyst, and undergo a ' rest cure.' After
a period of cjuiescence they quickly change into second and
active larval forms, which are minute, transparent, and quite
invisible. These lead a perfectly free life, and in wet weather
gradually siiuirm and crawl up among the leaves and flowers
of the heather, where they remain until swallowed by the
grouse. When once inside the bird, the larvae make their way
along the alimentary track, and enter the caeca, where they
rapidly develop into adults." Dr. Shipley also presents a
word-picture of what would be seen. if. by means of a gigantic
lens, a square yard of grouse moor were magnified a hundred
times : — " The heather plants would be as tall as lofty elms,
their flowers as big as cabbages, the grouse would be si.x or
seven times the size of 'Chantecler" at the Porte St. Martin.
Creeping and wriggling up the stem and over the leaves, and
gradually yet surely making their way towards the flowers,
would be seen hundreds and thousands of silvery white worms
about the size of young earth-worms. Lying on the leaves
and on the plant generally would be seen thousands of
spherical bodies the size of grains of wheat, the cysts of the
coccidium ; and on the ground and on the plants, as large as
split peas, would be seen the tapeworm eggs patiently awaiting
the advent of their second host. It is perhaps a picture that
will not appeal to All, yet it represents what, unseen and
unsuspected, is always going on upon a grouse moor." — See
" The Grouse in Health aTid Disease ; being the final Report
of the Conunittee of Inquiry on (~irousc Disease." Two
volumes. Illustrated. London, loll.

MORE ABOUT THE CORN-CRAKE.— The distribution
of this species {Crcx pratciisis). in England continues to call
forth observations, and Mr. I-'. J. Stubbs has some apt remarks
in 7'lic Zoologist for August. 1911 (page 315). He points out
that the disappearance of the species from the south-eastern
counties of England dates from about 1850, and ascribes this
to the change in agricultural methods that was in course then.
The bird formerly bred in the corn-fields of the southern
counties, which, under the old system of broadcast sowing,
would be a real sanctuary. In a drilled cornfield this is not
so ; the nest could not be hidden and would be an easy prey
to stoats. For this reason, and as the meadows are also
unsafe and pasture fields inadequate, the bird has practicallv
vanished as a nesting species.

The curious annual fluctuations of the bird are conunented on
by Mr. Stubbs, who says that the present year nuist be
reckoned a corn-crake year in Lancashire, the species ha\'i[ig
been commoner than for many seasons.

In the recently published " Fauna of the Tweed .\rea "
(1911), Mr. A. H. Evans reports that the bird is stated to be
decreasing in some localities there, but that it is sulificiently
plentiful in most parts. It is somewhat local, and almost
absent from the coast-lands where there are few grass fields,
but is common, not only in the lower valleys, but among the
hills in " Tweed."

PHYSICS.

By Ar.i'KEi) C. G. Egekto.v, B.Sc.

INAUDlBLi: SOUNDS.— The Umit of perception of
sounds of high pitch varies with the person. In general,
persons lose their hearing for very high notes as they get
older, and it appears that slight loss of hearing in the region
of these upper frequencies begins to occur during quite an
early age. Many cannot hear the sound of the bat squeaking,
or of certain insects. Very acute sounds are audible up to

thirty-eight thousand vibrations per second. Helmholtz gave
as the lower limit, thirty \ ibrations per second, and a regular
wave train of forty vibrations per second was the lowest
musical note. Thus the ear can perceive vibrations ranging
from thirty to thirty-eight thousand per second. No doubt
higher sounds are common in nature : it is probable that
animals have different ranges of perceptin;i. Many persons
with average powers of hearing may be deaf to vibrations of
thirteen thousand per second. In this connection it is
interesting to note that old people often lack the ability to
distinguish the letter " s " distinctly ; the telephone and the
phonograph also have difficulty in transmitting that letter.
Now, the hissing sound when analysed into a wave form is a
succession of waves with very minute irregularities on the face
of the wa\es, and thus is equivalent in its facility to detection
to a sound of very high pitch. Campbell and Dye have
published, in Tlw Electrician, iin account of some work on the
detection of inaudible sounds. The electric spark gives out
waves of sound which are exceedingly short and far too high-
pitched to be audible. The means by which the frequencies
of these sound waves are measured are very simple. The
oscillatory spark is arranged at the open end of a long
horizontal glass tube along which is shaken out a little
clyopodium powder. As the sound waves progress along the
tube they set the lycopodium in motion, taking it away from
the positions of least movement (the nodes) and laying it about
where the air is in a greater state of turmoil. It is, in fact, the
" Kundt's tube " arrangement which has been used to find the
velocity of sound in various gases ; for, by measuring the
distance between the small heaps of dust produced b\- the
particular note, the wave lengths can be foiuid and hence the
velocity (for the velocity equals the product of the freijuency
of vibration and the wave length). The method has various
applications, for, from the velocity, the ratio of the amount of
heat a gas can take up when free to expand and when con-
fined can be found, and from this again whether the gas
consists of a molecule possessing internal energy besides
translation, or merely ener.gy of translation : in the latter case
the molecule consists of one atom. In this way the molecules
of argon, heliunr, krypton, xenon, neon and mercury have
been found to be monatomic. That is, the molecular weights
equal the atomic weights. Campbell and Dye measured the
distance between the striations produced in the lycopodium
dust along the tube and found that they could measure in this
way sounds of a frequency up to eight hundred thousand per
second ; their results seem to show that, since two sound
waves are given out for each oscillation, the sound vibrations
are double the frequency of the electrical oscillations.

THE AMPALL. — A few months back I mentioned this as
one of the novelties in electrical instrument design which ha\e
been elaborated by Messrs. Paul. The instrument consists of
a moving coil unipivot gahanometer connected to a pair of
contact points a definite distance apart, such that if placed on
a copper conductor of one square inch in cross section a read-
ing of one thousand t = 2 millivolts) is obtained, if one
thousand amperes are flowing through the wire. The contact
block is strapped to the conductor, the cross section of which
multiplied by the deflection of the unipivot millivoltmeter gives
the current in amperes. The instrument can be used to
measure direct currents up to any value and can be instantly
applied without breaking the circuit ; it also provides a means
of testing the conductivity of joints, fuses and so on.

The unipivot system of suspension of the gahanometer
needle is very satisfactory, as it allows of great sensitiveness
with perfect portability. The moving coil has one pivot only
in the centre of a sphere of iron. The circular coil swings
freely about this sphere without touching the magnetic system.
.A circular well aged magnet is so situated that the field is
concentrated across the gap where the sphere resides. The
pivot is situated at the geometric centre of the coil, which is
also the centre of gravity of the moving system. The arrange-
ment, residing on the one pivot and held in position only by
a hair spring, is thus capable of considerable sensitiveness :
while the protection afforded by the sphere to the coil, pivot

410

KNOWLEDGE.

OCTOBICK. 1911.

and rod bearing the pivot insures the safety of the moving
coil system against a great deal of rough usage.

THE LL'MI.NOSITV OF THE ElKEFLV.^Coblentz and
Ives have made an investigation of the light emitted by the
firefly (Photiiiiis pyralis). They find that the radiation con-
trolled by the By is all in the visible region of the spectrum —
there appears to be very little ultra-violet radiation and no
infra-red. The light is under control of the insect and does
not appear to be stimulated by pre\ious exposure to light, as
with true phosphorescent substances. It is more probable
that the light is due to oxidation of some complicated unstable
fatty substance, the decomposition of which can be accelerated
at will by the insect, perhaps by a catalytic agent.

M.\(iNETIC ALLOYS.— .^n alloy of 62-0 per cent, of
copper, 25-0 per cent, of manganese, and 12-5 per cent, of
aluminium, and also another alloy 43-4 per cent, of copper,
18-1 per cent, of manganese, and 40-0 per cent, of tin
are the two most strongly magnetic of the non-ferrous
alloys. Ross and Gray have recently studied the effect
of annealing and quenching of these alloys and of such
simpler and less magnetic alloys as copper manganese,
manganese antimony, and manganese bisnuith. They find
that cooling to a very low temperature increases their suscepti-
bility. Annealing improves their stability and quenching
reduces the hysteresis (or lag of induced magnetism after the
magnetising force). It appears to be difficult to explain why
such alloys should be magnetic, though in most cases the
magnetic properties seem to be due to the formation of solid
solutions of binary systems (such as Mn.; .AL) in the rest of the
material.

ZOOLOGY.

By Professor J. Arihl'R Thomson. M..^.

MAGNALIA NATURAE: OK. THE, CKl^ATEK
PROBLEMS OF BIOLOGY.— This was the title of the
notable address which Professor D'Arcy Wentworth
Thompson, C.B., gave as President of the Zoological Section
of the British Association. F"rom its earliest beginnings, he
said. Biology has been a great and complex and many-sided
thing. Aristotle was all that we mean by naturalist and
biologist ; he gathered up and wove into his great web the
varied lore of fishermen and bee-keeping peasants, as well as
the learning of the Hippocratic and other schools of physicians
and anatomists ; but " every here and there, in words that are
unmistakably the master's own, we hear him speak of what
are still the great problems and even the hidden mysteries of
our science," the magnalia naturae, inquiry into which is
characteristic of the spirit of our time. The old questions
of vital activity and organic form, of growth and reproduction,
of heredity and variation, and the like, are being re-discussed,
and many sciences are now being brought to the aid of
biology. Very noteworthy is the renewed interest in the
validity of the rival interpretations offered by the mechanistic
and the vitalistic schools, whose antithetic views recall those
of Democritus and Aristotle respectively. But whether we
lean to the one side or the other, we must agree in the use of
physical methods, and Professor Thompson devoted a con-
siderable part of his address to showing that these are of
service in studying form as well as function. Surface-tension,
for instance, must count for much in determining form ; it is
one of the " means of morphogenesis," to use Driesch's
phrase. After • giving interesting examples. Professor
Thompson expressed his belief that " the forces of surface-
tension, elasticity and pressure are adequate to account for a
great nuiltitude of the simpler phenomena, and the permuta-
tions and combinations thereof, that are illustrated in organic
form." . . . But " though we push such explanations to
the uttermost, and learn much in so doing, they will not touch
the heart of the great problems that lie deeper than the
physical plane. Over the ultimate problems and causes of
vitality, over what is implied in the organization of the living
organism, we shall be left wondering still."

MOMENTUM IX EVOLUTION.— Professor Arthur Oendy
made an interesting suggestion at the British Association in
regard to cases where animals or parts of animals seem to
have acquired some sort of momentum, by virtue of which
they grow far beyond the limit of utility. Is there any con-
stitutional brake on growth, and, if so, are there occasions on
which the brake may be removed with results which ultimately
prove fatal r Professor Dendy asks us to consider the internal
secretions or " hormones " which in some cases act as a
check on over-growth. If it were advantageous for a structure
to grow big. and if that structure were one which grew
abnormally big when a particular internal secretion was
absent, then natural selection would favour those individuals
in which the relevant glands were least developed or least
efficient. The glands might disappear, or might cease to pro-
duce the particular hormone in question. The organ would
go on growing larger ; it would in the course of time reach its
optimum : but the brake having been removed, further growth
would proceed irrespective of utility. And as to exaggerated
structures which never had any value as adaptations. Pro-
fessor Dendy appeals to correlation. The removal of a gland
which controlled the development of a frontal horn might be
followed by the exuberant growth of an entirely useless
excrescenci'.

ARISTOTLE'S LANTERN AS AN OKoAN OF
LOCOMOTION. — Dr. James F". Gemmill connnunicated
to the British Association a most interesting study of this
wonderful piece of mechanism which Aristotle saw over two
thousand years ago. There is a rhythmic swinging movement
of the lantern, and progression is by a series of steps or
lurches which are more or less sharply defined. In each step
the urchin is raised on the tips of the teeth and a forward
impulse is given. Ui) by strong pushing or poling on the part
of the lantern. l6) by similar but usually less effective pushing
on the part of the spines, and (cl, after a certain stage, by the
influence of gra\'ity. The lantern is then retracted and the
teeth swing forward into position for initiating a new lurch.
For ordinary locomotion over more or less horizontal surfaces
under water the lantern is not needed, but Dr. (iemmill
indicated various conditions, normal and experimental, in
which it may be employed with effect. " The locomotor
action of the lantern is a particular manifestation of a
rhythmic functional activity, which can also subserve feeding,
boring, respiration, and possibly also the maintenance of
physiological turgescence in various internal cavities."

FOOD SUPl'LY OF AOUATIC ANIMALS.— Dr. W.
J. Dakin brought forward at the British Association some
interesting corroborations of Putter's theory that sea or fresh
water is more or less a nutrient fluid, there being more organic
carbon present in solution in the water than there is in the
multitudinous plankton that swarms there. Dr. Dakin has
tried to estimate the amount of carbon and oxygen required by
certain aquatic animals per day to cover the loss due to
metabolism. On the basis of this estimate, which is probably
verv approximate, a sponge 60 grammes in weight would require
to filter several thousand times its own volume of water per hour
in order to obtain sufficient food — " an altogether unthinkable
piece of work." A big Jelly fish iRhizostoiiia) would require
over seven millions of nauplius larvae per day. " It is quite
impossible for such large cjuantities to be caught, and eiiually
strange that remains of the creatures are so rarely found if
they have been captured as food." Another striking fact, or
result of calculations at all events, is that the "producers"
(the plant-planktont. are insufiicient for the "consumers"
(the animal plankton). High alpine lakes, for instance, in
which there is an outstanding production of animal plankton,
are almost deserts as far as plant-plankton is concerned.
What do these alpine crustaceans and rotifers feed on ?
Putter's theory is the only solution of the riddle. We come
to the idea that the water in lake and sea is food as well as
drink. There is bread in the waters — according to the
ingenious showing of Dr. D.ikiii.

CORRESPONDENCE.

ASTRONOMICAL OIF.RIES.
To the Editors of " KNOwi.KnGE."

Sirs. — I. — The subject of the brightness of a surface is one
presenting various problems which it is impossible to discuss
here. Mr. Bartrum will find a few of these in Parkinson's
"Treatise on Optics," Chapters II and \. In estimating the
brightness of Venus, Godfray assumes that the illuminated
surface appears uniformly bright and of the same degree of
brightness in all aspects. .As this is not true, the results
obtained are only approximate.

It is interesting to notice, although bearing only indirectly
on the subject, that the half Moon does not give half as much
light as the full Moon. The visible surface, except at full
Moon, is darkened by shadows cast by the irregularities, and
so the amount of light is diminished.

II. — The major semi-axis is called the mean distance, and
nnist not be confounded with the average distance. This
Latter depends upon what is taken as the independent variable.

The mean distance of a planet from the Sun can be easih'
found by taking the Arithmetical Mean of the greatest and
least distances. The former is a + ae, and the latter is
a — ae : the .Arithmetical Mean of these two is a, the Major
Semi-Axis.

III. — The gradual decrease of the eccentricity of the F.arth's
orbit which has been going on for thousands of years, and
which w'ill continue for a long time yet. causes the mean
motion of the Moon to increase. It is difficult to explain this
in ordinary language, and a niathematical investigation is
necessary.

Let S denote the mass of the Sun, K his distance from the
Rai'th, and r the distance between the Earth and the Moon.
When the three bodies are in a line the disturbing component
of the Sun upon the Moon is

r 1 IT

L(R-rl- R-J
where m is a constant. This is evident, since the disturbing
effect of the Sun upon the motion of the Moon is the difference
of its acceleration upon the Earth and Moon.

Now r is verv small compared with R. so that the above
2/1 Sr

rt2R-rn
R'lR-rF-J

equation becomes D =

R'

The disturbing acceleration in any part of the orbit of the
Moon depends upon the distance of the Sun from the Earth,
varying inversely as the third power of this distance. Let us
find the average for a whole revolution of the Earth, which we
may take to be performed in a time T. say. Let D' be the

4^ Sr ri; dt

T y u ' R"
From Kepler's Law that the radius vector sweeps out equal

2 ^' dt
unit time

average disturbing effect .'. D"

areas in equal times, we obtain
h say.
.'. R- de = h d t.

area described in

.'. D'

4m Sr
Th

The polar equation of a conic
b-

the semi latus rectum

.'. D' = 4m Sra
Th b-

or

dt
R

=

dw
Rh

dti

R

L
R

=

1 +

e cos

H. whei

1
R

=

a
b-

-d+e

cos D).

gives

T (l-+e cos H) d e.

Now/ il+e cos 0) d rt = «+e sin fl = 7r, taking w and o as limits

.'. D' =

4 M Sra T
Thb'

4 M Sr TT
ThaTd-e')

It is easily pro\cd that

h" = M L C and T =

2 7rai:

VmC

where C is a constant. (See Williamson
Dynamics, Chapter VII. Equations 30 and 3
proof. I

.'. Th = 2^ail a/17=2

and

1, for

D'

\/a(l ■
2MSr

e-|

Tarlton's
a simple

a" (1 - e"l i

It is easily seen that as e decreases, the denominator
increases, and therefore D' decreases. The efficiencv of the
Sun in decreasing the attraction of the Earth for the Moon
therefore decreases, and the mean motion of the Moon
increases.

It should be said that the amount of variation calculated in
this way, about six seconds a century, does not agree with the
amount of acceleration obtained by comparing ancient with
modern eclipses. It has been supposed that the discrepancy
arose from a lengthening of the day, due to a retardation of
the E.arth's rotation from friction of the tides. The subject
is. however, too long to discuss here.

iREV.I M. DAVIDSON.

THE FOURTH DIMENSION.
To the Editors of " Knowledge. "

Sirs. — 1 was greatly interested in Mr. .A. L. .Annison's
paper on " The Fourth Dimension " which appeared in the
June number of " Knowledge," and I have been expectantly
looking for the corollary to his useful piece of analytical
reasoning : I may have missed it, but I certainly have not
noticed it.

It appears to me that the logical deduction from his series
of analogies is that the Fourth Dimension is Density (5) ; I
believe you will find that this fits in completely, and satis-
factorily answers the demands of a Fourth Dimension.

Hence all physical substances could be expressed completely
in terms of L X B X H X 6.

.As this Dimension seems to have been overlooked because
so well-known under the term of " weight," it appears to me
probable that other dimensions may perhaps be recognisable
as yet other well-known physical or chemical properties of

'"'■^^^^^- ALFRED J. .MULLINS.

COMETS 1911 a AND c.
To the Editors of " Knowledge."

Sirs. — The following obser\ations of Wolf's and Brooks'
comets, respectively 1911 a and c. were made on the evening
ot August 20th, 1911, by the aid of the forty-inch refractor of
this observatory (Verkesl.

Wolf's comet (periodic), was very apparent in the forty-inch
and was in a rich field. Small. Slight indication of a
nuclear condensation. Near a small star.

Brooks' comet was observed, first with the four-inch finder
of the great telescope. The nuclear condensation was a little
more apparent than in previous evenings, but the comet was
generally about the same. The nucleus and matter extending
in all directions from it were all that were visible at one time,
on account of the size of the field of view ; the former, how-
ever, presented a fairly large disc and was nebulous in appear-
ance. The light of the nucleus was practically white. There
were several comparatively bright stars in the same field,
which were actually visible through the head of the comet,
apparently undergoing no loss in brilliancy whatsoever. The
field itself was very luminous, and in some parts the nebulo.sity
was more apparent than in others, w'hich fact indicated the
presence of a tail extending out into space, beyond the head
of the comet. FREDERICK C. LEONARD.

411

412

KNOWLKDGE.

OCTOBKR

l')ll.

THE VELOCITY Ol" LKtHT.
To the Editors of " Knowlkhgf,."

Sirs. — A Hasli of " forUed " li^htiiinf,' is visible to the eye.
and seems to take an appreciable time to pass from the
thundercloud to the earth. As the human eye is said not to
be able to see anythinj,' that takes less than about one-tenth
of a second to pass tlie line of vision, a flash of " forked "
lixhtnint; must take more than one-tenth of a second to pass
from cloud to earth, a distance of a mile or two. « hich would
be equivalent to a velocity of about twenty miles per second.

If this be so. is there not a very great retardation in the
velocity of light, at or near the level of the earth ? If light
travel at the average rate of one hundred and eighty-six
thousand miles per second, and so great a retardation is
caused by the density of the atmosphere near the earth's
surface, may not light travel at a very much greater rate in
space than one hundred and eighty-six thousand miles per
second ?

The experiments and observations for the calculation of the

vclocit\' of li'_;ht were made at or near the surface of the earth;

.uid if the earth's atmosphere does in any way reduce the

velocit\- of light, would it not be possible and advisable to

recalculate that velocity from experiments and observations

made at observatories situated from five thousand feet to

fifteen thousand feet above sea level? ^ „ /-ttitil-

Lr. K. Li 1 rSnrt.

cll'sti:rs and nebulae.

To tin- lutitors of " Knowledge."
Sirs, — Si'ptcmhcr nimiber, page J45. 1st cohmin :

"Clusters

and groups of stars . . . which seem to be connected
by a force acting far more powerfully and at greater
distances than gravitation."

1 understand that gravitation h.d.inccs tlic members of the
Solar system uith each other, and inferred that it has a
similar effect in all other systems and on every system with
every other. Hut Mr. Henkel suggests some other force which
seems imnecessary. ^ .,

QUERIES AND ANSWERS.

Readers arc invited to send in Questions and to answer the Queries wliicli are printed here.

QUESTIONS.

51. GEOLOGY OE SOUTH DORSET.— Would one of
your readers give me U few facts about the Geology of South
Dorset — the strata, fossils and minerals. The region of
greatest interest is the Swanage neighbourhood. c tj i?

bl. GENIUS AND ISOLATION.— I have a theory th.at

social isolation in youth is one of the primary causes of

genius. Can some one quote me proverbs and facts in

the lives of such men as Shakespeare and Napoleon, tending

to demonstrate this hypothesis ? ;, ,, ,,

^>. H. K.

53. STRANG!'" STARS. — Can any of your readers give me
particulars as to the three strange stars seen last month
on the right hand of the moon \\]\v\\ nrarlv at tlu' full in
the South-East.

I am told they only appear once in one hundred years ; is
this so ?

Some reference was made to these in a Scotch paper, but I

have seen no mention in any of ours, or " Knowledge."

The stars are not now to be seen. ,,, ,,

Walter Hradshaw.

REPLIES.

45. HEAT AND VACUUM.— The loss of heat by a liquid
contained in an ordinary vessel is due mainly to conduction.
Defining heat (in the sense of a high temperature possessed
l)y a body relative to its surroundings), as a state of increased
molecular motion, cooling results from conduction by
surrounding matter. If, now. such conduction be almost
wholly prevented by a vacmmi jacket, the most potent cause
of loss is removed, and cooling proceeds by radiation. This
introduces the conception of radiant heat, which is quite
distinct. Radiant heat is a wave disturbance which is
radiated through space like light, and which produces a
condition of increased molecular motion (heat) in any absorb-
ing matter on which it falls. The spectral location of the
radiant heat rays is in the infra-red. The full efficiency of a
vacuum ve.ssel can be obtained by making the walls highly

reflecting. ,, ,,t i-,

Charles W. Raffetv.

47. GRAVITY. — It is impossible for the atmosphere of our
earth or of any of the Planets to prevent bodies flying off into
space. If the absence of an atmosphere would mean that
heavenly bodies could not retain anything on their surfaces,
we might expect pieces of the Moon to be continually breaking
off'; for it is gener.ally admitted that the Moon is practically
devoid of an atmosphere. Of course, the resistance of the
atmosphere will always diminish the velocity of a moving
body, but this cannot have any connection with the point
raised by " Ignoramus," For instance, if we could fire a
bullet from the Earth with a velocity of about seven miles
per second, it would fly off into space, the Earth losing control
over it. This is based on the assumption that thei^e is
no atmosphere to hinder its motion ; the presence of the
atmosphere, however, would necessitate a velocity of projec-
tion greater than seven miles a second, in order that the bullet
might not return. Evidently, however, " Ignoramus " is not
considering such extreme cases as this, but seems to be under
the impression that bodies would rise spontaneously in the
absence of an atmosphere, and pass oft' into space. Not only
is this a false idea, but bodies would actually weigh more if
our atmosphere disappeared. The weight of one cubic foot
of air at sea level apd at normal temperature and pressure is
•0.S07 pounds. In acc6rd,-ince with the well-known law,
that bodies innnersed in a fluid lose a weight equal to the
weight of fluid displaced, a body of volume one cubic foot
would weigh -0807 pounds less in air at sea level than in a
vacuum. Evidently, then, there would be less tendency to fly
off, generally speaking, if we had no atmosphere. The simple
experiment of placing a few bodies under the receiver of an
air pump, and then producing a vacuum, will show that there
is no tendency for these bodies to fly off.

Whatever explanations may be given of the causes of
Gravity, whether due to Etherial Tension or to any other
cause, the fact that such a force exists cannot be denied. It
surely cannot have been seriously advocated in the sermon
referred to, that the earth retained bodies on its surface by
atmospheric pressure without the force of Gravity !

Henry E. Crick.

NOTICE.

ARTIFICIAL RAIN.— In a little pamphlet under this title
Mr. Emilio Olsson describes a sprinkling apparatus for crops
which he claims will take the place of rain in times of drought,
and he gives an account also of some experiments carried out

in the way of electrifying the water used. A certificate from
two engineers that the electrifying of the water reduced the
total h.udness and that it was able to kill locusts perfectly is
included. Mr. Olsson's address is 19, Southampton Buildings.

Knowledge.

With which is incorporated Hardwiclie's Science Gossip, and the Ilkistrated Scientific News.

A Monthly Record of Science.

Conducted by \\'ilfred Mark Webb, F.L.S., and E. S. Grew. .M.A.

XO\EMBER, lyil.

THE NEW ASTRONOMY.

III.-ST.AR CLUSTERS AXD NEBULAE.

By PROFESSOR A. W. BICRICRTOX.

W'itli aiiistratioiis from photographs by G. 11'. Ritchcy.

It seems Strange that astronom\-, with all the mar\els when star clusters are seen throu,i;h i^iant telescopes,

the\' appear to eclipse evervthing else for brilliant

re\ealed b\- the modern methods, has not a greater
hold on the human mind. But doubtless the wondrous
beautv of the heavens appeals far more to a shepherd
folk, w ith their ample night leisure, their clear sky,
their serene minds, than to city peojile. The
brilliantlv lighted streets of London outshine even
Sirius or the brightest comet. I have seen the moon
herself showing over the house tops as a feeble kind of
large artificial light. In a big city, music hall stars
are far more effecti\"el\' attractive than a shining star
cluster or even the whole gala.xy of the heavens.
Astronom\- too, has become somewhat drv and arid.
Official astronomers do not care for theories, for the
linking silken cords of correllation, that will weave
together their wonderful isolated threads of facts
and convert them into the shimmering fabric of a
beautiful and consistent scheme of creation so grand
and glorious as to be capable of giving hope and
energ\- to human thought, and high purpose to human
aims. Nevertheless the neglected celestial vault is the
stage of much romance and beauty. The moon under
a telescope of moderate power is an exquisite object,
and so is the crescent of \enus. the ringed planet
Saturn, or the spiral nebulae. But perhaps, as I
said in Harper's .Ma<>aziiu', Se[)tember number,
imagination is wanted : "■ Were we to picture time as
passing so swiftly that centuries were as seconds, to
the eye of the mind we should see the star clusters
appearing as moving masses of manv-hued fireflies,
the planets as rings of silver light, and we sliould
see the whole stellar heavens astir as a swarm of
shining bees." No imagination seems to be required

magnificence.

The Wundkk and Bkautv uf Star
Clusters.

These groups of celestial gems may sparkle like
diamonds of the first water, or they may shine
with man\- a \aried tint, some blue be\'ond the
Oriental sapphire, some vivid green, or red, or purple.
Some of the groups are all white : some, as in the
constellation of the Southern Cross, are white,
interspersed with red. blue, and green stars : while
the most wonderful of all the clusters, that in the
Toucan, is of an exquisite rose tint. Then the
number of component stars is wonderful : in most
clusters they may be counted by hundreds, in some
there are manv thousand independent points of light,
everv point of light a sun perchance bearing a
planetar_\- s\-stem with it. \MTat possibilities unfold
themselves. Think of an\' one of those solar s\stems
threading its w ay through the ma^e of the other suns.
What vicissitudes it must encounter. For hundreds
of vears it might revolve amongst the densities at
the centre of the svstem : then its orbit might be
deflected and for thousands of years it might travel
towards the exterior of the cluster. With the
sudden effect of natural selection, on the satellites
of such a sun, the changes from tropic to arctic
diu-ing the great glacial epochs of the earth would
hardh" compare. Then, again, how the hea\ens must
alter in aspect within those wondrous coloured
clusters, where in one part the emerald and the

413

414

KNOWLEDGE.

November, 1911.

ruin' enhance their mutual heautw and in another
the topaz and the sapphire nutglow each other.
Imaj^ine oneself the inhabitant of a planet lit by a
ruin' sun and an emerald sun. Consider the brilliant
pictures and the shadows, every shadow dt)Lible, one
coloured red and the other green. These wonders
seem too much for full description. So I will not tr\'
to describe the effects as seen li\ the iiih;ibitaiits o(
planets uitlnii a coloured
star cluster: I leave
to the readers
" Knowledge " to

a

'ine the scener\'

It

of

im-

for

themselves.

Collisions in
Clusteks.

The great Humboldt
asked this most sug-
gestive question : " How
can these systems be
maintained — how cati
the suns, crowciing at
the interior of star
clusters, fulfil their re\'o-
lutions freely and with-
out clashing." Do they
re\'ol\'e without clashing?
The answer is: Almost
certainlv the\' occasion-
ally clash.

N o v a e s o ni e t i m e s
occur in star clusters
as do main variables.
We Ikinc alread\' proxed
that the impact of suns
absolutely must produce
new stars, and Nature
seems to offer no other
suggestion of then-
origin. E\'ery such im-
pact must strew the
space about the point
of collision w ith meteoric
and gaseous matter,
which must exercise

A tvpic-il star clustKr with a condensed centre ; a more

difliised one, tliat (jf w Centauri, was shown on page J4J ol

the September issue.

a retarding e

ffect

upon

it, and produce other
stars over the cluster.

the suns passing through

imi)acts strewing variable

l'2ver\ such collision lessens the nuitixf energy

of the (luster, and helps to weld it together,

until hiialh', after eons have passed, a \'ast nebulous

sun m.'i\' result.

Till-; Genesis oi- Clusters.

How do star clusters originate ? Possibly they
are the nuclei of vast third l>odies th.it have been
striK:k from gigantic suns, or perhaps the result
of whirling coalescence, where great angular motion
prevented condensation to a centre. We ha\'e
already seen that selective molecular escape must
rob the bodies at unstable temperatures of their

light gases, whilst a vast expanding rotating mass of
elements of greater atomic weight will be left behind,
that is a rotating meteoric swarm. Such a rotating
mass will not (|uickl\' tend to concentrate to a centre,
the angular velocit\' will keep the particles in orbits.
These orbits must be continually crossing one
another, and although the general rotation of the
mass will be m om- direction, as the swarm will be

rougliK' spherical, the
indivitlual particks w ill
be in orl)its in all
azimuths. Hence, in-
stead of concentrating
to a [ilane as they wnuld
[probably do were they
subject to ;i great
central controlling force,
the\' will tend to aggre-
gate into larger and
larger fragments, the
whole retaining some-
what of a globular form.
Small swarms of this
character would prob-
abh' give rise to some
of the comets, but it
would not be the only
method of their forma-
tion, as impact shows
us, man\' modes by
which dust swarms may
originate. \'er\' gigantic
swarms would, as the
ages rolled on by con-
tinued coalescence gradu-
allv form star clusters
in which the constituent
suns would be somewhat
similar in mass.

Impacts within star
clusters would not be so
liable to produce double
stars as under ordinary
circumstances, because in
proportion to the mass
there must be a very con-
siderable orbittil proper
motion. Hence, although we should expect a fair
number of very transitory novae and a great number
of xariables in special parts of star clusters, or in
special clusters, we should not expect a great
number of dt)nble stars. The whole subject of the
internal motions of star clusters is one worthy of
ver\' careful stud\' on the [:art of the astronomer. We
shall require to know much more than we do about
these motions, before there can be any certainty as
to the origin of clusters.

The suggestion here niadc as to their genesis has
considerable elements of probabilit}', but is certainly
not an absolutely demonstrated deduction, as is the
partial impact origin of new stars bv the formation
of the tliird bod\'. Nor does it compare in

Cluster M.i

e'anes 'Venatici.

FkU'UK 1. Spiral NfbuUi M..S1. I'rsac Majoris.
I'mbablv a case of whirling coalescence of two i;lobular nebulae of abont equal volume and mass.

415

416

KNOWLEDGE.

NOVEMUKH, 1911.

probabilit\' with the iniiiact origin of variable and
double stars : in both of which cases the evidence is
so conclusive that it is certain that a very large
number of the wonder and double stars of the
heavens did actualh- originate from the grazing
impact of suns.

Planetary Nebui.aic.

There is \'erv strong e\idence, indeed, that most,
if not the whole of the so-called planetary nebulae,
originated from the impact of suns. It is almost
certain that Herschel's wonderful suggestion as to
the physical character of these bodies is true. He
examined these circular discs of faint even light uith
great care and he tells us that only one possible
suggestion of their character offers itself. The\-
cannot really be

discs, or they would ; |

sometimes be shown
to us more or less
edge on : they can-
not be continuous
spheres of gas, or
the edges would be
much less brilliant
than the central
portions. The onlv
explanation left, in-
conceivable as it ma\'
seem, is that they
are hollow shells of
gas. How such
bodies could be
formed appeared to
him a mystery, but
it is ob\iousl\' a
clear and simple deduction,
properties of the third bod\
le of

than the critical \-elocity will be carried to enormous
distances, and will not tend to concentrate back
again, because the rotation will give them an orbital
power.

In every stage of atom sorting there will tend to
be ensphering shells, in which the lighter gases w ill
be the outer ones, and consequently many of the
planetarv nebulae wdl have a sphere in sphere
structure.

The Centre oe the Planetary Nehclae.

Thev should also often have centres consisting of

Sometimes this centre
a rare meteoric swarm, such as seems

material of greater density.

would be
to be the
nebulae.

case with
Both of

- V n c zo^/.

LKH _;. WVbl/s XfliuLu

continumis spectrum tile mete<inc miclei within
tile ensphering; shells.

:ao jot iM

I I I. I M M

4. Struve's Nebula.

DiaL'ram sliuwin^

in spectrogram that concentric layers are of difterent
elements

Struve's and Webb's planetar}-
these nebulae, as shown by
Keeler's drawings,
•» exhibit also the

-J sphere in sphere

«;. structure. (I'igures

j and 4.) Sometimes
the meteoric swarm
would be dense
enough to appear
stellar, perhajis with
a velvetv structure.
Some of the planet-
ary nebulae actually
do exhibit such a
star. In some cases
the two suns would
be entrajiped into a
double star the dis-
tance of whose
constituents from

t.

w lien we
anil appK"

app

study
tci it

the
the

The Origin

We have already

ht gases, must under man\

OE Planetary Nehijlae.

shown that the high kinetol of
the light gases, must under many and varied circum-
stances cause such elements as helium, hydrogen,
nebulium. and so on, to leave systems. We have
also seen that on the birth of the third body, the
atmospheres of the suns must be at the centre of the
mass, and as expansion occurs these light gases

gra

dualh

ike their way out. By taking energy
from heavier elements these light atoms attain an
escaping velocit\'. It is clear that this inversion of
the position of the elements could not occur
suddenly. At the birth of the third body, the light
elements do not mo\e faster than the heavier ones.
This increase of speed is obtained as the
temperatures tend to become equal, consequently
much of the later escaping hydrogen will not possess
anything like the speed that some of the light
material, better situated, will attain, and hence
some of it niav only have a \elocity approximately
that of the critical velocity. The whole third body
is rotating, and hence particles with slightly less

one another might
be \'er\' small conipared with the dimensions of
the planetar\- nebula, for some of these extraordinary
bodies have dimensions that are inconceivabl\' stu-
pendous. The orbit of the earth would be as a child's
hoop in a continent, compared with the vast dimen-
sions of some of these celestial shells of luminous gas.

I think it extremeh' probable that every planetary
nebula is gas that has been produced by an impact
of suns, gas that has sorted itself, by selective
escape, into a condition of practical stability. The
planetar\- nebulae that are known to result as the
final stage of many temporary stars need not
necessarily be permanent shells ; the speed may
be so great that the material may be carried on
into distant space, or not great enough to form
permanent gas shells. The width of the lines in
the spectrograms would tell much as to this velocity.

The same remark applies to planetary nebulae as
was made regarding star clusters. Their character
and motions should be studied in the light of the
new astron(jmy of impact, to ascertain how far they
tend to give solidity to this new theory, or to
modif\" some of its conclusions.

White Nebulae.
Covering vast regions at the two poles of

the

November, 1911.

KNOWLEDGE.

417

Galactic circle are
hundreds of thousands
of nebulae. An immense
number of them are of
an exquisite double
spiral structure. In the
next article, in describing
the origin of the Galaxy,
we shall attempt to shoN\'
that these nebulae were
extruded during the
coalescence of the twi)
cosmic s\stems w hich this
theor\- suggests went to
the formation of the
system of stars that is
commonh- known as the
Universe. It will lu'
explained that the Milky
Way is the result of
what we have called
" Whirling Coalescence,"
and that the two great
sheets of nebulous
matter that now clothe
the two poles of the
Galaxv were ejected
during the earlier periods
of coalescence by the
agencv \\e have named
" Axial extrusion." In
s t u d \- i n g . then, the
origin of these double
spiral and other white
nebulae, we have to
assume that the two
poles of the Galax\- were
at one time covered w ith
vast continuous sheets of
nebulous matter which
the action of " selective
molecular escape" had
largely robbed of its
light gases. Into such
a sheet of material, the
manv errant masses that
are sent out of systems
bv the agencies described
in "The Birth of Worlds
and Systems" would
penetrate, and would
gradually be volatilised
bv friction, and would
form cometic nebulae,
de\eloping into roughly
globular nebulous con-
densations. These
portions would be denser
than the general sheet
of nebulae. Any con-
densed masses that were
near one another would

Taiin at lV</!-i->' Obsei-;iti'ry fchuary 7—S, /Q/v.

Figure 5. Spiral Nebula, Canes Venatici.

A probable case of oblique impact between two nebulae of

extremelv diflerent volumes. A considerable. portion of the large

nebula remains at the end of the spiral.

Tai-cn al Vtrkcs Oi-s.-f^-atmy Mar fS, lolo.

Figure 6. Spiral Nebula, M.64. Comae Beren.

.A probable case of whirling coalescence of two previously

existing nebulae.

be influenced by mutual
attraction, and approach
one another. Lateral
attraction of other
nebulae would, as a rule,
prevent direct impact,
and hence the approach-
ing pair would move in
curved orbits and come
into grazing impact.
This graze may, of
course, be of any depth,
as already suggested in
the case of grazing suns.

The Effects of
Depths of Graze.

The mere margins
mav collide and, as they
do so, the impact would
greath" increase the
temperature, and hence
the luminosity, of the
colliding margin, and
then, after a long period,
a streak of light would
exist between a pair of
more or less globular
nebulae — a condition
that not i n f r e q u e n 1 1 \'
shows itself in connection
with double nebulae.
In certain positions we
should obviously ha\'e a
nebula somewhat of a
dumb-bell shape.

If the graze be deeper,
we should have a vast
spindle - shaped nebula
produced as a third
body, only, unlike that
of the suns, it would
be of extreme tenuity.
But the kinematics of
the two are the same
and hence rotation will
ensue, and a spiral begin
to show itself in the
centre of such nebulae.
We know of many ex-
amples of this, that of
Leo being very beautiful.
As time rolled on such
an incipient spiral would
complete itself, and we
should have a double
spiral structure. Such
a definite structure as
this would not be
possible in the case of
the grazing impact of
dense bodies like suns,

41S

KNOWLEDGE.

November, 1911.

because the explosion of the third body would he
of such thermodynamic intensity as to blow the s{)iral
to pieces.

Whirling Coalescence of Nebulae.
Again, imagine that the globular nebulae strike so

as to give us cases of whirlint

deeph

On the grounds of both
deduction and observa-
tion, this would seem to
be the general case of
nebular collisions. When
we look at the kinetics
of this special class of
impact, this deduction is
verv strongly supported.
Let us examine such a
case of the coalescent
collision of globular
nebulae. The pair have
penetrated deeply the one
into the other, the por-
tions outside the range
of actual collision would
be carried forward by
their own momentum,
but would be subjected
to the attraction of the
vast third body produced
by actual collision. The
capturing power of the
third bod\- would cur\e
these portions into a
double spiral. The
middle portion would,
however, be so intensely
heated that a good deal
of it would be expelled
both by selective mole-
cular escape, and by axia

coalescence.

Taki:n at IVv/i-o Ohs^t-^ratory Marc'i 0—7, IQIU.

Figure 7. Nebula, y.\'.24. Comae Beren.

Probably a high velocity case of whirling coalescence, in \ihich

the outer parts that have not come into collision still remain as

non-luminous dust, and so obstruct the light of the spiral.

extrusion. Consequent 1\

the attraction would weaken, permitting centrifugal
force to act and allowing the two great tongues of
tire to proceed outward, as two giant arms of an
immense double spiral nebula.

.\gents Modifying the Spiral.

All kinds of modifications of the form of this
double spiral may be due to differences of size, or
difference of density, of the impacting nebulae.
One or both of the two colliding masses may already

be made up of more than one centre of conden-
sation. In this N\ay the two arms may differ so
much in volume from one another, that it may
form a \'ast almost independent nebula at the end
of one of the arms : such as we see so strikingly
in the great nebula in Canes \'enatici, (Figure 5).

Li the case of pre\'ious
rotation, the original
motion would give great
irregularit\' to the arms
of the spiral, and even
tend to give it a multiple
appearance. Of this
resultant motion we have
ver\- many examples.
Hence it seems that we
have but to study the
kinetics and kinematics
of the various impacts
of nebulae, and every
element of m\ stery in
the origin of their form
and structure disappears.
When we take into
account differences of
densitv, differences of
volume, differences of
depths of encounter,
differences in the stage
of impact, there is
possibh" no single form
amongst the hundreds of
thousands of those photo-
graphed, but \\e have a
clear dynamical account
of their evolution. Thus
\\e are presented with a
set of principles that abso-
luteh- explain the origin of each and everv one of these
exquisite celestial flouers, the glowing nebulae that
we find in every stage of bloom in the celestial fields.
In our next article we shall attempt to show that
bv applying the same reasoning, as here gi\'en to
nebulae, to the impacts of svstems similar to the
great clouds of Magellan, the mvster\- surrounding
the birth of the grand Galactic svstem we call the
visible universe is in like manner completely
dissipated, and the whole C}'cle of the eternal heavens
is revealed to our mental gaze.

FOURIER'S SERIES IN THE '• ENCYCLOPAE DLA BRITANNICA."

To those with a taste for mathematics here is fine food,
Fourier's invention of the series bearing his name formed a
landmark in Mathematical Science at the beginning of last
century. He shewed by their means that it was possible
under certain circumstances to represent any discontinuous or
arbitrary valued function by an even series.

Interest is added to the study of these by knowing that they
have considerable application in physical science, especially in
the theory of heat.

The article in the Ency^clopaedia treats the subject very
ably and explicitly, and gives a few well -chosen simple
graphical examples.

Preceding the article on Fourier's Mathematical work is one
giving a short history of his political life, from which we learn
that P~ourier, in addition to belonging to the company of
illustrious men of science that France has given to the world,
also achieved unconnnon success as a politician,

T, W, K, C,

PSYCHICAL RESEARCH.

By

ARTHUR HILL.

It is related of Mmc. de Stacl that she did iidt
belie\'e in ghosts, but that she was afraid of them
all the same — " /c iic Ics crnis pjs, iiiais jc lea
cniiiis." The \\itt\' Freiichwdinan's epigram con-
tains deep psychological truth : foi- our emotions
are not ruled bv our reasoned l)elicfs. And, in
addition to its true psychology, it accurateh- des-

cribes the attitude of the average

though he

ma\' not confess it so frankl\-. Wo don't believe
in ghosts — oh, no. not realh' believe in them. But
we are at times a little — just a little — afraid of
them : sav, for instance, when going to bed at two in
the morning (at which \vmv. accorciing to Napoleon,
courage is at its lowest ebb) up the gloomy stair-
cases and in the draught\- corridors of an old and
lonely house, with the wind soughing and sobbing
and wailing in the trees outside^likc the wraith of
poor Cath\- in " Wuthering Heights." At such times,
we have inner qualms, step we never so boldlw

The recent advance in certain bN-jiaths of science,
however, seems likely to go far towards effecting
a change in popular opinion and popular feeling.
The ghosts, like evers^thing else in this extremel\"
scientific age, are now being studied and examined.
and photogiaphed and dissected (or would be. if
they had any insides to dissect), and the prospects
are that before very long, we may get so well
acquainted with these ciiiiiiiulae vafJiilae that we
shall no longer be afraid of them. Then we shall be
able to reverse the epigram : instead of disbelieving
yet fearing, we shall believe but shall not fear. This
consummation may be displeasing to the ortlu)dox
haunting ghost, whose business is dike the Fat Boy's
in "Pickwick)." to make our flesh creep: but, on the
other hand, it will meet with the approval of all
sensible and well-disposed spirits, such — for ex-
ample— as Mr. Stead's friend Julia, of whom we
have lateh' been hearing so much.

The " spirit " cjuestion, however, is the wrong end
of the subject to attack. Of course, when an appari-
tion does turn u[) it is the percipient's scientific
duty (if he can keep his wits about him sut^cientlv
to do it well) to obser\-e it, to make careful notes at
once, and to get them signed — along with a doctor's
certificate of sobriety — b\' corroborating friends.
Then, if the person represented bv the spook is after-
wards found to have died at the time of the vision,
we have good evidence for some kind of supernormal
agenc)-. Or if — as is most likely — he did not die :
if. indeed, he was in specialh- good health and
spirits at the time; if. in short, our hallucin-
ation was due to indigestion las the doctor probabh'
assured us), we naturally feel a mild regret
that the Societ\- for Ps\chical Research should

have lost a promising '" case," but, on the other
hand, we ha\-e at least retained our friend,
who — perhaps equalK' naturally — will be apt to
regard nur aforementioned regret with a feeling akin
to resentment. But, even in cases of veridical
hallucination — i.e., hallucinations which seem some-
how connected with distantly-occurring events, and
which are therefore " truth-telling " — even in these
cases, the scientific value of the phenomenon itself is
perhaps less than that of many apparently less
important happenings. For it is not the mere estab-
lishing of the actuality of an alleged i>lunomenon,
that constitutes its value to pure science. It is the
linking of it up with facts already known : the fitting
of it into the mosaic of already organized knowledge:
the bringing of it into the domain of law : — it is here
that the main business and interest of the philo-
sophical scientific man are to be found. And. in the
case of ghosts, this linking up, and fitting in. does
not seem likeh' to be an easy matter, even if the
facts are satisfactorily established.

It was therefore with deeji wisdom that Sir ()li\er
Lodge, in "■ The Survival of Man," which is the
latest important pronouncement on the subject,
decided to begin at the other end. Instead of
plunging into the description of phenomena which
puz/le us because they seem so out of relation with
our scientific know ledge, he starts by giving a lengthy
and careful description of some experiments of his
own which seem to establish the fact of thought-
transference or ■■ telepathy." In these very matter-
of-fact and unghostly experiments, the chief parts
were plaved b\' two \oung ladies who were emplo\'ed
b\- a Liverpool firm, of which Mr. Malcolm Guthrie,
I. P.. was head. (^ne of them — the receiver or
■■ percipient " — was blindfolded, though as an aid
to passi\'it\- of mind rather than as a precaution.
The other — the "agent" — concentrated her mind
on an object selected by Sir Oliver, trying to
impress the idea of it on the mind of her friend.
Care was taken, of course, that the latter was
afforded no ojiportunity of seeing the object, or
of gleaning any information of its nature by
normal means. Many of the experiments were
made w ith ordinarx' pla\ing cards ; for, In- this
means, the likelihood of chance coincidence could
be mathematically determined. In one series which
Sir Oliver quotes, the successes were ten out of
sixteen. The chance of this occurring by accident
can be shown to be less than one in ten million.

Im-oiu this we go on to telepathy at a distance.
Recent exp(^riments between Miss Miles and Miss
Ramsden. carried out in accordance with suggestions
made bv Professor Barrett, indicated clearly that

4iy

420

KNOWLEDGE.

N(>\EMBER. 1911.

some supernormal agenc\' was at work. The dis-
tance between the e.xperimenters \'aried. as one of
them was tra\'elling about : chn-ini; part of the time
it was about four hundred miles. Often, the exact
idea sent b\' the agent was received hv the per-
cipient, who sat alone, at a specified hour, waiting
]iassively for ideas to drift into her mind. .\t other
times, the message received was not that which had
been consciously sent, but nevertheless represented
something which had been occup\ing the agent's
mind during the da_v. b'roni this it appears that
the agent's subconsciousness, as well as the ordinary
conscious level of the mind. ma\- ha\e something to
do with the pmcess.

With this in mind, we go on to consider a
different class of [)henomena. I'/c.. what is called
hv spiritualists "trance - nicdiumship." and b\-
ps\'chical researchers "motor autnmatisni with
obscuration of the sujiraliminal consciousness." or
other terms to that effect.

It is a common thing for a sitter with a trance
medium to be told the most astonishin;_;l\- correct
and intimate details of his famil\- life, the names iif
his relatives, and so on, although, so far as he knows,
he is an entire stranger to the medium. The
intelligence, or control, purports to be a guardian-
angel sort of spirit, who h.ibituallv s[)eaks through
this medium, and who sa\s that he or she is getting
the information from spirits who ai'e the sitter's
deceased friends or relatives. Sometimes one of
these latter is allowed by the " guartlian-angel
sjiirit " to take personal possession of the medium's
body, and thus to sjieak directlw In such a case
the astonished sitter {i.e. if he is a no\ice) finds
himself addressed in characteristic fashion b\- some
dead person, reminded of little experiences which
the\- had shared in life, and is [>erhaps ultimateh
convinced that he is \erital)l\ in direct communion
with the tlisembodied mind of his relatixc or friend.
When the medium wakes up. she (it is usualh' a
'"she") has absolutely no knowledge of what her
vocal organs ha\'e been sa\ing.

Now how are we to set about explaimiig all this ? '--'

The first thing to make sure of is, of course, that
ordinary fraud is excluded. This is usualh' a fairly
easy matter. When the sitter can question the
" spirit" (as in these cases he always can) it is easy
enough to get satisfactory assurance that common
trickery is not the correct explanation ; for questions
can be asked concerning family matters, or mutual
ex[)eriences, of which the medium could not be
normall\- aware, even assuming the emplo\ nient of
skilful and energetic (letecti\-es. Moreo\-er. in se\eral
cases knoAu to me, the sitter gave either a false
name, or no name at all. In one of these cases, the
sitter was a friend of mine, living two hundred nules
from London, where the sittings took place, and the t\
there is no reason to suiipose that he was in the
least degree known to the medium. He was not a

spiritualist, luul no spiritualistic friends, and had
never sat with a medium before. Yet the guardian
or "guide" ga\'e m\ friend's two Christian names,
with a good deal ot true detail aliout his life, and at
the second sitting, two da\s later, he was greeted
by an intelligence purporting to be his recentlv-
deceased mother, who alhuled b\- name to all the
near survix'ing relatives, with appiopriate comment
and attitude, and ga\'e other evidence ot a
characteristic and con\'incing nature. My friend
had gone into that room a sceptic, bent on
" showing u|) " these trick\' mediums : he came out
absoluteh- convinced that he had spoken with his
deceased mother. I express no opinion, except that
some supernormal explanation seems to be required.
(I nia\- also remark that this case, considered in full
tletail. is much more evidential than this necessarily
short description can indicate. It is described in
full in m\' just-published book. " New E\'idences
in I'sschical Research." (William Rider cS; Son,
Ltd. Js. 6d.)

I-'rand being excluded, we turn to other possible
theories : and, hearing in mind the fact of thought-
transference or " telepathy " — already established
by experimental methods — we surmise that the
medium has somehow read the sitter's thoughts.
The fact that the tiance-control's remarks do not
coincide with what we were thinking of at the time,
is no obstacle, tor. as we saw in the case of Miss
Ramsden. it is not alwa\s the agent's conscious
thought that is reproduied. The medium's trance-
consciousness ma\' be able to rummage among our
memories, selecting those which stick together round
a gi\en personalitx'. .\s to the \-erisimilitude of the
characterisation, this is easih' comprehensible : for it
is a well-known and continually-observed fact that
m the hx'pnotic state man\' subjects are excellent
mimies, and hxqmosis is undoubtedly related to
" niediumistic " trance.

It follows, then, that nothing more than thought-
transferenci' need be supposed, so long as the medium
tells us nothing excejit what we already kno\\. But
what shall we sav if things are told us — things
characteristic of the soi-ilisant spirit — which have
ne\er been known to us, but which on investigation
turn out to be true ? Well, this certainly complicates
matters, but, knowing that telepathy can be effected
over great distances, as in Miss Miles' and Miss
Ramsden's experiments, we are able to suppose that
the fact in question has been somehow telepathicalh'
gleaned from some distant mind. It is. however,
clear that in making this supposition we are treating
two cases as analogous, which differ in im|iortant
features. Miss Miles and Miss Ramsden are well
known to each other, are, in fact, friends: and,
though the consciously-attempted message sometimes
failed, another (which was not " sent ") taking its
jilace, it must nevertheless be borne in mind that

■xpe

rimenters were thinking of each otl

fre(|uentl\, and that there was thus a certain rapport
between them. \Miereas. in some of these trance

Novi;mhi;r, 1911.

KNOWLEDGE

421

me^snges. the person whose mind must he supposed
to hiive suppHed the information is a person who
has never seen the medium : is not known hy the
medium: is unaware of a sitting being in progress, and
therefore is not thinking of anything of the kind: is
indeed perhaps unaware of the medium's existence,
and hostile to psvchical research and all its works.
The conditions are therefore xerv different from
those of experimental thought-transference. Still.
this latter fact having been established, and its
possible range not vet being satisfactorily defined,
we are bound by the law of parsimony to work tele-
pathy for all it is worth, before turning to other and
more far-fetched-seeming hypotheses. So long.
therefore, as anv living mind contains a fact w hich
is retailed bv a control as evidence of its identit\'. we
must suppose that it ma\" be a case of telepath\'
from that living mind.

I sav we must suppose that it may be. It docs
not b\- any means follow that it is. Some of the
cases quoted by Sir Oliver Lodge as occurring in
his own experience with Mrs. Piper, though possibh
explicable by telepath\". are nevertheless strongh'
suggestive of the action of a disembodied intelli-
gence. For example, a "spirit-communicator"" in
Mrs. Piper's trance claimed to be the deceased son
of Mr. Rich, the then Postmaster at Liverpool.
This entity wished a message to be sent to his
father, who was said to be worrving specially about
his son's death. The sitters knew Mr. Rich slightly,
but knew nothing about the matter dealt with in the
message. This latter, however, was duly delivered,
and turned out to be appropriate to. and charac-
teristic of. the deceased voung man. The excep-
tional worry or grief was due to a slight estrange-
ment, which would ha\e been only temporary. If
we are to invoke telepathy in tbis case (and it is
only one of many similar ones) we are driven to
the curious supposition that Mr. Rich subconsciously
sent a telepathic message to Mrs. Piper (whom he
did not know, and who did not know him) and that
this message was dramatized and returned. In other
words, that he sent a deceptive message to himself —
via Mrs. Piper, and bv means unknown to science —
w ithout knowing anything at all about it ! It seems
almost as easy to believe in the prima facie exjilana-
tion {i.e. genuine spirit communication) as in such
mar\'ellous telepathic exploits as this.

l)Ut is there — it may be asked — any way of
putting it to the proof ? Cannot telepathy be shut
out, somehow ? Cannot crucial tests be devised ?
On this very important point several acute brains
have been cudgelling themselves for man\- \ears.

It was at one time thought that the best test
would be the posthumous reading — through a
mediumistic communication — of a sealed letter left
in the keeping of a friend. Such a letter was left
with Sir Oliver Lodge by Mr. Myers : but the
attempt by a soi-disaiif Myers-communicator to give,
through Mrs. X'errall's automatic writing, a repro-

duction of its contents, was ;; complete failure.
It is now recognized that the test is not a good one :
for, even if it succeeded, it wouid not yield proof.
It would still be possible to suppose that the
deceased had. before dying, unconsciously " tele-
pathed" the contents of his letter to some person or
other, and that, when a medium somew here produced
the message correctly, it was through telepathy from
the subconsciousness of this hypothetical person.
Or. again, the letter, though sealed, might be read
"clairvoyantlv." Some such power is often alleged,
and there is a good deal of evidence in its support.
Further, is it not too much to expect that a spirit
will remember what the letter contains? Sir Oliver
Lodge has not prepared such a letter, for he is ipiite
sure that he would forget what he had written.
Probabh- most people will feel similar doubts about
their post-mortem recollection of such matters.

The sealed-letter test. then, is given up as unsatis-
factor\-. What shall we turn to next ?

It was thought b\- Mr. M\ers and Professor
Sidgwick that it would be rather good e\idence if
the same message could be obtained from the same
spirit through two or more mediums. Some experi-
ments in this direction were made, but apparently
without much success. After the death of these
two leaders in the research, it was natural to expect
that they would themselves try something of the
kind from "the other side."' in order to give us
evidence of their continued existence. And. as a
matter of fact, this seems to ha\e happened. The
same message, almost word for word, was received
from a Sidgwick-control through Mrs. Thompson,
in London (sitter, Mr. Piddington. Hon. Sec. of
the Societ\- for Ps\chical Research), and Miss
Rawson. in the South ot France. Hut the
telepathic difficulty again arises. The two
messages were not exactK' simultaneous. Is it not
possible that Miss Rawson's subconsciousness made
up the message (it was one giving some instructions
to Mrs. Sidgwick about the preparation of her
husband's " Life''), and then telepathed it to Mrs,
Thompson ? It is of course necessary to suppose,
also, that the subconsciousnesses of the two mediums
were in league to represent the message as coming
from Dr. Sidgwick. But if the heart of man is
deceitful above all things, and desperately wicked,
there is no knowing to what depth of sin these
newh-discovered "subliminals" mav descend. We
must hold them guilt\- until we have proved them
innocent. In this case, once more, then, telepathy
is not excluded.

At this jioint the ingenuity of the earthly investi-
gators seemed to come to a stand. There seemed no
way of getting round this omniscient and omnipotent
telepathy. It seemed impossible to devise any
experiment which should shut out with reasonable
certitude the agenc\' of minds still in the body.
Just about this time, however, a curious thing
happened.

422

KXOWLEDCxE.

NOVKMBKR, 1911.

For some years after Mr. .Myers's death in l')01.
automatic writing had been regularly produced by
several people of social and educational standing —
not professional mediums, or even siiiritualists — who
were more or less in touch with the Society for
Psychical Research, and whose script purported to
emanate parth' from the sur\iving mind of F. W. H.
M\-ers. Chief among these automatists is Mrs.
\'errall. Classical Lecturer at Newnham : others are
Mrs. Holland (an Anglo-Indian lady, who did not
know Mr. M\-ers) and Mrs. Forbes, the widow of a
well-known judge. These scripts contained much
evidential matter, but it was usually open to the
telepathic explanation, though some of it admittedly
strained that explanation rather severely. Still,
telepatln- was possibly the true theory. I^nit.
in i90(). it was discovered by Miss Johnson (the
Research Officer of the Society for Psychical
Research) that there were curious concordances in
these scripts, concordances which apparently had
been going on for some time. It was found that one
script, sa\- Mrs. X'errall's, would contain a piece of
writing which was apparently meaningless, and which
was so treated by the automatist, while another
script, sav Mrs. Holland's, written about the same
date, would contain a message equally meaningless in
itself, but which, when compared with the similar
one in Mr. X'errall's script, produced the most start-
linglv good sense. Here. then, apparently, was
found evidence of initiative "on tlie other side." for
none of the living investigators had thought of this
plan of splitting a communication up and giving it
piecemeal through different automatists. (See Pro-
ceed iims of the Societv tor Psvcliical Research, \'ols.
XXI an.l XXII).

These remarkable phenomena are. howe\cr. still
not quite ccjnclusive. Perhaps the ingenious and
sportive snbliminals of the automatistsconcerned have
arranged an elaborate system of impersonation,
telepathing these message-fragments to each other,
while the normal consciousnesses remain ignorant
of all this below-decks cross-firing. The hypothesis
cannot be entirelv put aside ; though it seems very
improbable to those who ha\'e made a careful study
of the whole mass of evidence. As Sir Oliver Lodge
has said, it is too early to formulate dogmas, or even
to express opinions (on the spiritualistic question)
except in hesitating and tentati\'e fashion. But the
evidence now certainly seems sufficient to justify the
holding of at least a working hypothesis that in these
experiments the minds of " dead "" persons are really
playing a part.

This, however, is a very different thing from an
acceptance of "spiritualism." with all its crudenesses
and follies. The spiritualists — or most of them —
accept any sort of trance-ravings or automatic
scrawlings, as genuine '" messages " from " the
beyond." Psychical research, on the other hand,
criticallv examines the content of the messages,
applving the most drastic tests before even admitting
other than known causes. If the communications

contain nothing that is not kn(.)wn to the medium,
psvchical researchers dismiss them as of no interest :
unless, indeed, there is a cross-correspondence
involved — i.e., the same message, or a related one,
being given through another medium. If the
medium's own knowledge is undeniably insufficient
to account for the facts, then telepath}' is invoked,
and is stretched to a fearsome extent, amidst the
violent diatribes of the spiritualistic jiress, which
stigmatizes the Society for Psychical Research
as a Socict\- for Suppressing Knowledge. If
telepathv begins to seem insufficient, some few-
bolder spirits of the Society (incarnate ones)
\'enture on the tentative h}-pothesis of " telepathy
from the dead : " but w ith careful hesitancy,
leaving the door open behind them in order that
the\- ma\- fiee back to the safet\' of former and more
orthodox views, if further investigation should render
the new tentative hypothesis untenable. This
perhaps undignified but certainh' wise position is
that which is at present occupied by Mrs. Sidgwick
(the ex-President of the Society), Sir (Oliver Lodge,
and other leading members of the Society for
Ps\chical Research. The present writer, who
is also a member of the Society in question,
adopts a similar attitude. Personal investiga-
tion has con\inced him of the truth of Hamlet's
well-worn remark to Horatio, and lu' is even
inclined to think that some of the evidence
justifies us in thinking that (to be Shakespearian
once more) not onl\- can we call spirits from the
vast\' deep, but that sometimes they will coiiie
(though ot tlu'ir own free will) when we do rail
for them.

It is a difficult subject, not suitable for everyone.
Emotional and unbalanced people should be warned
oft. Even religious people are doubtfully desirable :
the in\-estigation should be carried on, as far as
possible, in the pure dr\- light of science, as it has
been in the past, b\- men like Sidgwick, Gurney,
M\'ers, and Hodgson. We want no recurrence of
witchcraft and superstition, of which, perhaps — after
the materialistic extremes of nineteenth century
science — there is some danger, the pendulum of
popular opinion being apt to swing from one side
to the other. But, this said, we may follow up our
researches with an eas\' mind. \\'e are certainly on
the track of something, whether (in Professor
Barrett's phrase) it be a " new world " of being,
or not. Careful and honest and patient investiga-
tion will no doubt yield its reward : but no sudden
revelation is to be expected or desired. It ma}-
require the labours of many generations to unfold
the full significance of the discoveries which are now-
being made. For it is not onh' in the (possibly)
spiritistic direction that our pioneers are making
progress: we are also finding out much concerning
the unsuspected powers of the human mind
(telepatliN", clairvovance, and so on), while it is still
manifesting itself through a material brain in the
ordinarv earthb' life.

ON ADJUSTING AN EQUATORIAL BY MEANS OF

CIRCUMPOLARS.

Bv E. AKDRON HITTOX. M.A.

Thk a\'erage amateur astronomer usualK' suffers from
the complaint of a hoh' discontent. He gets first
of all a three-inch instrument on a tripod. He
finds that he cannot conveniently use a power of
more than one hundred and twenty, and so procures
an equatorial stand and a couple of clasps, and then,
by the aid of the usual text books, sets about its, or
rather, their, adjustment. It must be confessed that
the result is not always satisfactory, and in man\-
cases a low power eyepiece is first used as a finder,
a higher power being afterwards substituted. The
object has then disappeared from the field before the
new focus is found, and has to be "fished" for by
the Right .\scension screw. Many of the objects in
Webb cannot be seen at all with a low power, or at
least cannot be distinguished when the field is
crowded with stars, and thus much time is lost and
many objects too. Xo amateur ought to be satisfied
until he can infallibly pick up an\- object desired in
a field of fifty to the inch of aperture.

The want of a sidereal watch can be easily supplied
by obtaining a cheap Waterbury at the cost of half
a guinea. Its adjustment to sidereal time. b\" aid of
the " Sidereal time at Noon " given in Whitaker, is
the work of a few days onlv, especially where a good
clock is at hand. The first stroke of the hour from
a public clock w ill usually be the best to adjust b\-,
and if the time by the watch is put down on paper,
the rate is eas\' to determine, but patience should
be exercised, and the exact three minutes fift\'-six
seconds gain per day striven after. The subsequent
rate may usually be relied upon to within ver\- few
seconds a day.

The adjustment of the clasps to the stand and
to the telescope ma\' then be seen to. The holes in
the Declination plate should just fit the lugs of the
clasp, and if there is any play wedges of thin zinc or
tin (not wood), must be used. Two large washers
for the screws to work against should also be pro-
vided, and everything should be screwed up well and
firmh'.

If the clasps are not quite right in size, two pieces
of sheet lead of suitable thickness should be wrapped
round the telescope, and then screw on the clasps.
No \\edges of irregular size and thickness must on
any account be used. The telescope should, of
course, be clasped tightly, and no plav of an\- kind
should be even suspected.

The adjustment of the instrument ma\" then be
taken in hand, and for this the method given in
Chambers and Loomis leaves nothing to be desired,

if faithfullv and thoroughly carried out. Few, how-
ever, amongst amateurs do this, and hence a final
testing by means of circumpolar stars is desirable
and often essential.

For this purpose, either the upper or lower cul-
mination of an}- circumpolar will suffice, but u and X
Ursae minoris are far the best, and the following
method may be adopted.

A quarter of an hour or so before the actual
culmination, the Declination circle should be brought
to read the true Declination as given in the " Nautical
.\lmanac." minus the correction for refraction. The
R.A. circles should be set to the true R.A., and to
time respectively, and the screws at the bottom of
the Polar axis adjusted so as to bring the star
exactly in the centre of the field of an eyepiece of
not less than fifty to the inch of aperture, the teles-
cope being East. Every care should be taken to
perfect this adjustment and not to be content with
mere approximation only. Exactness in this point
is essential.

The telescope should then be swung over to the
Western side and the circles re-fixed anew. If the
star is too high or too low it is probably the Declin-
ation vernier that is wrong, and the star should be
again centred by the Declination slow adjustment
and the new reading taken. Half of this will be the
error of the Declination vernier, and it must be
altered accordingly. If the star is right in this
respect, but appears to the East or West of the
centre, a packing of thin metal must be put under
one of the clasps until the error is halved. This is
the commonest fault, and though it ought to have
been detected before in the observation of six-hour
stars, yet, too often, it is passed over as "near enough."
.\ very small amount of packing will suffice, and
nothing is more convenient than a sheet of thin lead
from a tea chest, to be obtained at the grocer's
for the asking, .\gain, however, we must insist
on exactness, for nothing else will suffice, .\
second, or even a third, testing will be amply
repaid. The time vernier may then be finally
adjusted in the meridian by transit of an equatorial
star, as given in the text books.

The consequence will be that powers of one hundred
and fifty or two hundred may be used, with the
assurance that the object will be in the very centre
of the field of view with ordinary care in setting the
circles. There will be no "fishing" or waiting, and
above all there will be no mistaking one object for
another, or concluding that it is beyond the power

423

424

KNOWLEDGE.

XOVEMBEK. 191 I.

of the instrument. Six-hour stars will be equalK"
easv, allowing, of course, for refraction, and the alter-
ation of eyepieces will be speedih' dispensed with.
Above all, the amount ot work done will be immensely
increased, and the comfort of an exactlv-adjusted
instrument the better appreciated.

The larger the instrument the smaller the objects
attacked, and the more necessar\- the exactness

required, since (iftentimes two or three douliles will
be found in the field, and to know one from the
other is hv no means easy. .\ little care thus
bestowed will be ampl\- rewarded, and the obser\er
will become the more satisfied with his hobby, and
instead of sclccfiiii; objects from Webb, will icork
tlimiii^h the book with ever-increasing satisfaction

and delight.

CORRESPONDENCE.

THUXDERSTOKMS IN (iAKPlSSIO.
To the Editors of " Knowledge."
Sirs. — The fnllowiiT,; imti^ ;iiid accompanying sketches

jr~?^

Figure 1.
Five long ribbons of Lightnins^.

were made at Garessio. a small town in the Ligurian Alps.
about thirty kilometres inland from .Alassio. and at an altitude
of six hundred metres above the sea.

The summer in that part of Italy has been a remarkable
one. not as has been the case in F.ngland and Northern

F^IGURE 2.

Mamillated cloud after a thunderstorm. loi:>kin,t; north.
August 29th. 1911. 1.0 p.m. Garessio, Italy.

Europe, on account of the heat and drought, for our inaximnni
temperature never exceeded 29° C. (84 ■ 1 FM, and the first
part of the summer was so exceptionally wet that crops and

flower gardens suffered greatly. The characteristic of this
summer which has made it a remarkable one was the
extraordinary pre\aleiice of thunderstorms, and the unusual
intensity of the electricity developed. There were thunder-
storms, either close at hand, or within visible and audible
distance, on twelve days in June. tweUe days in July, and
sixteen in August.

In these storms, which usually culminated between one p.m.
and four p.m., the lightning was magnificent, ribbons of fire
running across the sky for miles, accompanied by a continuous
roar of thunder. Usually the flashes leapt from one towering
cumulus to another at an enormous height, and almost always
without rain. Only on one occasion was there a little
hail. I ha\e endeavoured to sketch one remarkable flash,
because neither I nor any of those who witnessed it can
recall ever having seen a similar phenomenon. The sky
had been dotted for several hours with curious irregular-
shaped cumuli of extraordinary hardness and compactness,
e\identlv highlv charged with electricity, and ascending

W^^^jfc.

-^n*-

F^IGURE 3.

Mamillateil cloud after a thunderstorm, looking south.
.Ans;ust 29th. 1911. 1.15 p.m. Garessio. Italy.

in tall columnar masses much like the steam from a
locomotive's funnel. Suddenly one of these seemed to
become over-charged, and a violent and very rapid discharge
commenced, one flash of which I have endeavoured to depict.
(Figure 1.1 From a distinct centre of the cloud there burst
simultaneously five long ribbons of lightning, which traversed
a space of absolutely blue and cloudless sky. and ended
abruptly in the blue, as shown in the sketch. There was no
other cloud above or near the thundercloud, and the five
streams appeared all of equal length. The sun had recently
set behind the hills shown on the right, and the sky was still
luminous and blue. I have never observed such a thing before,
and should be interested to know whether it is a well-known
phenomenon — that is to say. the lightning travelling out of a
cloud into space and there terminating.

The two other sketches I send because I remember seeing
a letter and illustration some time ago in " Knowledge." re-
cording a mamillated cloud. These mamillated clouds are not

NOVKMUIiU. 1911.

KNOWLEDGE.

425

by any means uncommon amongst the Ligurian .Alps, but I
have never observed them except immediately after a thunder-
storm, and they are apparently developed in that part of the
thunder-cloud which represents the pointed end of the

Thor's .Anvil," as it is sometimes called, — the long smudge
which streams out behind at the opposite extremity to tlie
advancing cauliflower-liUe front of the cumulus.

On the occasion on which the two sketches [Figures 2 and
i] were made, the whole sky was covered with these clouds.
I took a photograph of part of it. but the result was too uniform
in tone to come out well in reproduction. In my sketches I
have slightly exaggei'ated the light and shade, but the forms
were drawn with all possible care and accuracy. The rounded
out lines of the pendant clouds appear to be due to the fact
that the clouds are descending — that they are. in fact, cumuli
upside down. After one of these storms we had the rather
rare pleasure of seeing a perfect and very beautiful lunar
rainbow (July 11th). ^^,^,^ PARKINSON (M.A.. O.xon.)

OMPOSITIOX OI- T.ACHINIDAE.
To the Editors of " Kxovvledgh."

Sirs, — I observed two of these flies the other day (July 25th,
1911) while attempting to lay eggs on the larvae of GlottiiUi
doniinica, which were feeding on the leaves (and inside
them, under the epidermis! of a species of Crinum.

One of them was feeling a larva near the head with its
front pair of legs, as it now and again extended its ovipositor
forwards under the thorax (I saw no eggs actually deposited).

The other saw the movements of a larva which was feeding
under the transparent epidermis while about two inches off,
and rapidly making its way there apparently succeeded in
laying its eggs through the epidermis of the leaf on to the
caterpillar, but of this I cannot be certain. The former larva
was crawling on a neighbouring leaf and was not under cover,
but it defended itself by swinging its tail round and
discharging some liquid at the offending irritation.

I have noticed that a Tachinid is usually recognisable by
the way in which the antennae stick out from the head during
life, but the antemiae of these two flies seemed to be in danger
of getting broken off, and they reminded me irresistibl\' of a
terrier's tail when he smells a rat !

L. Ct. GILPIN-HKOWX.

STANUAKL) TIMi: IN ToKTUd LKSE TKKRITORIES.
To the Editors of " Knowledge."

Sirs, — I beg to inform you that Standard Time will be in
use from 1912, January 1st, throughout Portuguese territories,
as follows : —

S*" 0"' E. Macao, Portuguese Timor.

5" 0" E. Portuguese India (provisionallv 5" 30'" E.I.

2" 0" E. Portuguese East Africa.

jh gm £_ Portuguese West Africa.

O'' 0" (Greenwich, or West Europe). — Portugal, St.

Thome and Principe Islands, Whydah.

l'' 0™ W. Madeira, Portuguese Guinea.

2" 0" \V. Acores, and Cape Verde Islands.

This Observatory remains entrusted with the determination
and the telegraphic transmission of Standard Time to the
whole country, to the Lisbon Time-ball, and to the Time
Stations at the Meteorological Observatory, Ponta Delgada
(St. Miguel, Acores).

I take this opportunity to state also that the most reliable
geographical latitude of this Observatory is :
Lat. N. 38° 42' 30"-5 (prime vertical, meridian, and zenith
telescope series of observations
from 1872 to the present, printed
or unprinted),
and that the name " Lisbon, Tapada " is now the most
suitable for it, like, for instance. " b'lorcnce, Arcetri," or
'■ Naples, Capodimonte."

There has been built, and has now been working for two

years a new astronomical observatory at Lourencjo Marques,

whose geographical coordinates are (transit pier) :

Lat. S. 25°58' 4"-9 + ()"-2 (Meridian observations by

Capt. Gago Coutinho.)
Long. E. 32° 35' 39" -4 + 0"-05 (Moon culminations, simulta-
neously here, and geodetic
connections with the Cape. )
Altitude (top of pier) 59 metres.

CANYOS RODRKjL'ES,

Vice-Admiral, P.N., Director.
Observatorio .Astronomico de Lisboa.

DARK-GROUND ILLUMINATION AND ULTRA-
MICROSCOPIC VISION.
To the Editors of " Kn'owi.euge."
Sirs. — In view of the great number and variety of dark-
ground illuminators and appliances for ultra-microscopic
observation which have come into existence, it is a matter for
regret that makers ha\e not always been felicitous in the
choice of descriptive terms, and it is not improbable that in
many cases this may have encouraged a pretty widely spread
tendency on the part of users of the microscope to confound
enhanced visibility with increased resoKing power, witli the
result that a considerable amount of cc^nfusion has arisen
respecting the fundamental aspect of the two modes of
observation.

Neither the method of dark -ground illumination nor the so-
called ultra-microscope can in any true sense of the term be
regarded as a means of enhancing the resolving power of the
microscope. In accordance with the undulatory theory of
light this can only be accomplished by increasing the aperture
of the optical system or by diminishing the wave length of the
light. In their fundamental physical aspects the method of
dark-ground illumination and the obser\ation with the ultra-
microscope are identical, and both ser\e to enhance the
\ isibility of an object.

.At the bottom of the secret which underlies these methods
is the simple and familiar fact that brightly illuminated objects
can be seen more distinctly on a dark back-ground than on
one which is itself bright. Two things happen when a bright
object is seen on a black ground ; objects which were visible
on a bright ground become much more distinct, and other
particles which could not be seen before will come into view.

When this principle is applied to the microscope it is found
that in the field furnished by the method of dark-ground
illumination details can be observed, especially in preparations
containing micro-organisms, which cannot be recognised under
ordinary circumstances, though dimensionally they are well
within the resolving power of the microscope. In addition,
particles become so far visible that their presence can be
percei\ed, and this despite the fact that their dimensions may
be considerably smaller than the wave length by which thev
are seen, and accordingly beyond the resolving power of the
microscope.

So long as the objects as seen in a dark field exhibit structural
details and well defined contours we are dealing with simple
dark-ground illumination. When, on the other hand, the field
is seen to contain particles in which there is not a visible trace
of detail and which accordingly present the appearance of
bright point-like discs, generally surrounded by bright and
dark rings, the case is one of ultra-microscopic observation,
and the particles whose presence is thus perceived are ultra-
microscopic.

It will thus be seen that the dift'erence lies solely in the
manner of observation and not in the nature of the apparatus.
On the other hand, ultra- microscopic observation implies
dark-ground illumination, whilst it is not every form of dark-
ground illumination that constitutes an ultra-microscope. For
this reason it is most desirable that the various appliances
should bear appellations from which it is at once apparent
that they are primarily intended for dark-ground illumination,
pure and simple, or for ultra-microscopy, as the ease mav be,
i.e., dark-ground illuminators should be named so as to
distinguish them from ultra-microscopes.

It should, howc\er, not be oxerlooked that in practice it

426

KNOWLEDGE.

November, 1911.

Irequently happens that a darU-ground ilkiiiiinator. i.e.. a
condenser primarily devised for ordinary microscopic observa-
tion in a darU field, is available for ultra-microscopic observation :
indeed, in many cases both kinds of observation are made con-
currently. The examination of a preparation of saliva
furnishes an instance of this. With our concentric condenser
(after Dr. Jentzsch of our Scientific Department) one can see
in this medium a few organisms moving across the field in
snake-like fashion, and others of a rod-like shape, whilst in
addition to these there are to be seen bright discs surrounded
by one or several bright rings and e.xecuting quivering move-
ments. The latter come into view by an ultra-microscopic
process, whilst the others are seen under simple dark-ground
illumination, though sometimes their trans\erse dimensions
are of the ultra-microscopic order.

It is to be hoped that in future, makers as well as users of
these optical instruments will endeavour to prevent a contin-
uance of the misunderstanding at present existing, by employing
the correct term, especially when referring to dark-ground
illuniinatiun of micro-organisms. ]•'. Ll-IT/.

TH1-: NKW .ASTRUNUMV.
Tu the Edtturs uf " Knowledge."

Sliss. — I was delighted to see your able statement of the
facts confirming Professor Bickerton's theory in your August
issue, and still further pleased to read his remarkable articles,
on the story of Nova Persei, and on double and wonder stars.

I ha\'e always lo\-ed astronom\', and for thirt>' \ears I ha\e
been a Fellow of the Royal Astronomical Societx', and during
all that time nothing has interested me so uuicli as this
beautiful theory of the third body.

At Professor Bickerton's lecture at the Roval Colonial
Institute. I heard Mr. Knobel. who has lieen twice President
of the Royal Astronomical Society, express his opinion so
strongly. that I was delighted. He said: " It has been an extreme
pleasure to me to listen to Professor Bickerton's eloquent
address. I have given some attention to astronomy mxself.
and I can saw that the basis of Professor Bickerton's theory
is such, that it nmst command, not only the attention and
consideration, but I tliiiik. the assent of the niajoril>- of
astronomers."

Since this lecture as I have gradually realized how iar-
reaching is the scope of the principle of the third body, w ith
its power to capture, its explosive energy, and its capacity to
sort its atoms, I have come to believe that this generalization
marks an epoch in astronomy. I heard Professor Bickerton
debate the subject, at the British Astronomical Association,
and was struck with the ease with which he confuted the
objections of able astronomers. Hence I felt assured that
the theory had come to stay, and subsequently his letters in
TIic Times confirmed this impression. I have read and re-
read his book, " The Birth of Worlds and Systems " published
in ■■ Harper's Library of Living Thought." Its study convinces
me that the theory of Professor Bickerton's, is the only one
that corresponds with the facts of observational astronomy.
With regard to novae, the question so ably discussed in the
September number of " Knowledge," I have personally
compared the light-curve, and series of spectrograms of Nova
Persei, with the complex deductions made from the dynamical
study of the third body, and they fit perfectly. I believe that
the Southern .Astronomers are right when they say that. " had
the idea been used from its inception, merely as a working
hypothesis to guide celestial observations, astronomy would
have been years ago where it is now." The Government of
New Zealand has shown its deep interest in basic science,
and deserves the gratitude of the learned societies, in sending
Professor Bickerton to explain his New Astronomy to the
scientific world. J. McCARTin'. I'.'r.A.S.

TO FIND .\P1'R( JXIM.NTI'.L'i SIDICKF.VL TIiMIC.

Tu the Hditors uf " Kxowli:dge."
Si us. — The state of the sky at a particular hour may be
approximately ascertained by the use of the simple equation

*Note. — Line I - Setles is t'assiupeia's Cliair ; line 5 — .^rgo rises

Tanantis is

l\.A. = h-h2m -(-.T. where h is the hour counting from
midnight, and m the number of the month.

This will gi\e the R.A. of the zenith, or Sidereal Time on
the 7th of the month, within a few minutes. By the daily
allowance of four uiinutes the R.A. on any other day of the
month may be determined. Thus, on the 22nd of the month
the R..\. w'ill -^h + 2m + 6.

N.B. — For greater accuracy in January and February the
dates should be the 6th and 21st, and in March, May and July
the .Sth and 23rd.

E.xaiuple: .\t noon on November 2'Hh, st-ven days after
tile 22nd; R.A. - 12 + 22 + f->h. 2.Sm.^XVI.2.s'. The correct
time, as shown b\' W'liitaker's Aliiuiiuiek is X\'1.20' 1".

.\g.iiu. if the 1\..\. of .1 particular st.ir or constellation is
known, its pci,.,ition in the sky at an>- dale .md hour may be
calculated.

Example: The R..\. of Siriu.-. is \'I.4r. To find the time
cif its southing on 15th March, seven d.ivs after the 8th.

R..\.- VI.41 -h-f 64-5h. 2.Sm.

.'. h — — 5h. 47m., which signifies ,t hours 47 minutes
befcire 24 o'clock or midnight; which will be XIX. 1,1 o'clock,
or 7.1 .! p.UL

.\gaiii, to find the date on which a given meridian will be
south .it ;i partli nl.u' hour.

Example: When will Alt.iir. R.A. XIX. 4(.. be south at
O.JO p.ni.:-

R.A. = XIX.4(i-21h. .i()m. + 2ui4-rih. Kini.

(The last figure nmst be chosen, so that the \.ilue of 2in will
be e\en.l

.'. 2m-XIX.4(.-XXVII.46= -.S,= +l(i, .'. m = 8.

The dati' will be .August 26th, four days after the 22nd. By
Whit.d;cr. R..\. at noon on .August 26th is X.14; at 0.30 p.m.
it is XIX.44.

In the .ib.sen(e of a Star .Atlas or Map. the following lines
ui.iy be useful: —

Mi;m()KL\ Techmca'
shineiii:; the pnsilioii of the prineipal stiir.s in tJie sky.

Sides. .Andromeda, et PISCFS, et Cetus, .Achernar.

Perseus. Plei:idesi|ue, .ARIES, Mira, Eridauusque,

.\in'iga, Orion, T.AURUSque, Lepusque, Columba.

lum GEMINI, Procyon, et Sirius, atipie Canopus.

CANCER, et Hydra, .Argo, cui puppim \ela seqiumtur.

Indicat Ursa Polum coeli, tergunique LEON IS.

Cauda, Canes, VIRGO, Corvus. Crux, et Centaurus.

Lrsa. Draco, .Arcturusque, Corona, et LIBR.A. Lupusque.

litanin, Heracles. Ophiuchus. SC( )RITO, et Ara.

A'ega. Caput Cygui. Volucerque Tonantis. et ARC US.

Cepheus, et Cygnus, Pavo, C.APRICCJRNUS, et Indus.

Pegasus, .Australis qnoque Piscis, AOU.ARIUS, et Grus.
These lines, taken in order, give the constellations found in
the segments of the sky contained between the R..A. meridians
XX1\' and 11, 11 and \\'. ]\' :ind \'I. and so on.

i'ri:d p. tawa )R.
Tin; I'UKKiNji: imii;nomi;non.

To the Editors of " Knowledge."
Sirs, — It is a matter of conunon observation that coloured
objects change their aspect in a remarkable manner just after
sunset. If, for instance, when twilight has set in, we look
about us in a garden containing flowers of various hues, or in
a library full of nruiy coloured books, we soon become aware
of a striking change which has taken place in the relative
brightness of the tints surrounding us. We notice that the
blues are much lighter, and the reds nmch darker than when
they are seen in ordinary daylight. So marked is this
phenomenon at times, that certain blue tints appear almost
white, while red tints, on the other hand, become so dark that
they might be mistaken for black, if, indeed, they do not
entirely pass unnoticed. The cause of this well-known effect,
which bears the name of the Bohemian physiologist Purkinje
(17S7-1S69), who first described it, generally receives its
explanation in the peculiar differential colour sensitiveness of
the eve, which loses sight of a red sooner than a green ray.

stern first ; line 7 — Cauda is the Bear's Tail : line 10
.\(juila.

A'lilucer

November, 1911.

KNOWLEDGE.

427

when adapted to twilight vision. The eye, in fact, aeeording
to this view, iiiMst be adapted to twilight, or must have the
so-called " Dark-adaptation," before the phenomenon can be
produced. The retinal apparatus of the eye undergoes a
certain change when dark -adaptation occurs, the rods of the
retina, which are distinguished from the cones by the posses-
sion of a substance peculiarly sensitive to the action of liglit
known as " visual purple," being more particularly in\ohed
in the process.

So nmch, then, for the physiulo^ical explanation of those
curious changes in the rclatise brightness of colours at dusk,
known as the " Purkinje Phenomenon," and this is, in essence,
the explanation given by Dr. Charles S. Myers in his
recent science manual ",\n Introduction to Experimental
Psychology""; but it appears to nie that there are other
factors of a purely physical character — factors which I have
so far never seen adduced — which also conspire to bring .about
the remarkable effects observed.

Every photographer must be familiar with the extraordinary
change of aspect which coloured objects suffer when seen
under the red rays of the dark room. Reds appear very
bri,'lit, and blues correspondingly dark, for he is regarding
them by what is practically monochromatic light of a red hue,
and only those objects whose surfaces are capable of reflecting
the red light waves will show brightly: all others must appear
dark in comparison. Now. when the Sun has set, we have the
reverse phenomenon, for our source of illumination is the blue
sky only. The Sun, which sends us rays of all wa\e-lengths,
being below the horizon, surrounding objects can only
be rendered \isible by the sunlight reflected from the
minute particles of the atmosphere, and these, as we
know, send us predominantly light of short wave-length,
so that we here again have a quasi-monochromatic effect.
This bluish light, therefore, will be strongly reflected by all
objects of a blue tint, rendering them brightly conspicuous,
while, conversely, all red objects will appear correspondingly
dark — we shall have, in point of f.ict, a displ.iy of the
Pmkinje Phenomenon.

While in no way venturing to impugn the validity of the
physiologic.d interpretation of the phenomenon, as first
described, it seems to nie that we possess in the purely
physical aspect of the question an equally powerful, if
generally neglected, factor contributing towards the identical
result. ' W. .\LFK1£D PARK,

n.\ki:d-i-:vi-: comp.ts.

T(i the Editors of "Knowledge."

Sirs. — The fact that four comets have been visible to the
naked eye within two months must furnish a fact of exceptional
rarity. I saw Kiess's comet on .August 3rd without telescopic
aid. Hrooks's on .August 15th. and Quenissett's on September
2Sth. .And during the past few mornings Beljawsky's comet
has been very generally seen as a conspicuous object in Leo.

Brisiol October Sth. '^^'- F- Dl^NNINHi.

ASTRONOMICAL nU L.RIES.
To the Editors of " Knowledge."

SiKS, — May I be allowed to thank Dr. Crommelin and the
Rev. M. Davidson for their lucid replies to my (juestions in
your issue of August, and to add some further remarks ?

On the first two (juestions I have nothing further to say,
except to express surprise that the Nautical Almanac should
publish the time of greatest brilliancy of Venus to the nearest
hour when such accuracy is of no significance. In this
connection I should like to refer to the ease with which the
planet was seen at Hampstead at inferior conjunction on
September 15th, when within nine degrees of the Sun himself.

With reference to my third question, dealing with the Moon's
secular acceleration, I had no intention of submitting an
astronomical catch but was in a real difficulty, though I found
the fallacy in my own argument shortly afterwards. My
solution, which agrees in its results with that of .Mr. Davidson,
is as follows ;

* Ciuiitjiidge Uni\

Taking D. the disturbing acceleration (using the same
notation as Mr. Davidson), as proportional to the reciprocal
of the third power of the earth's radius \ector.

Then the a\-erage value of D throughout a complete
revolution of the earth is

1

1- - f 'it , ,. .

D = K / - . . where K i.-, a consi.u

T J „ R'

it.

From Kepler's Law. 1

. d II
\' - — C, a constant.
dt

TT

Hence, D' -= -^ -"_
C T .

f do

From the equation to

11- I. b'

111 ( ■ 1 1 1 n c (-1 \\ — —

an cmpst, i\

a [I + e cos l>

TV

T T I -. ' K (7

Hence, D = — - ,
C /r

." / (1 + c cos"l do.

_ K

a Zw_

C

b- T

T

W

Al,o, T =- 2 f'dt =

-- -- / W dO;

C / 0

Hut (/ '^ -"- - d 0, wIk.tl- <I> is the ciiiiipkiiiciit of thr
K

eccentric angle.

.And R = <;(! + e sin ■/)!.

TT

Hence. T = ^ I''' / 0 + e

'J

sin '/'I (

_ 2 ab T

C '

Hence, D' = K -L = K

1

rt (1 — c I

From this it appears that, as e decreases and D' conse-
quently decreases, the Moon will be accelerated. Hut yet I
am not satisfied. The problem is to show that the ai'era^e
angular velocity of the Moon in her orbit increases as the
eccentricity of the Earth's orbit decreases. The above shows
that the average perturbing acceleration decreases with the
eccentricity, and we know that the angular velocity increases
with decrease of perturbing acceleration ; but I submit that
these are not sufficient to prove the proposition. It seems
possible that there may lurk here a fallacy similar to that with
which I began this correspondence.

Perhaps my meaning will be clearer if I put the matter into
symbolic form. The angular velocit>'. w, being a function of
D, we have w = '/' (D) say.

„- , ,, i d( (D)) .

W e know that ; is negative.

d D

(1)

Wc ha\e found that d ( / D dt ) is positive (21

de

But does it necessarily follow that

■■A IDI dt I is negative? (.i)

de
We still require to know the relationship a ~ >(■ IDI.

1 do not. of course, doubt the well-recognised truth of (31,
but 1 venture to think that it does not follow from (1) and (2).

C. O. HARTRU.M.
eisil)* l'i'es>, 191 1.

PLANT HAIRS.

r.y K. E. STY AX.

iCoiitiinuil fniiii Pane 24R).

IV. — {a) Sti-:i,i,atk and [h) Pf.i.tati: 1'i,a\t

Haiks.
As tliL' wiird implies, stellate hairs are raxed aiui

Stellate Hair^

•"runt \ieu . Side \'ie\v.

I-'UUKE 1.
from the Stem and in\ulucral bracts uf
Mouse-ear Hau kueed.
starlike, though the
ra\"s spread out in all
manner of strange
\\a\s (some of them
being simple, others
branched into two or
more arms) and are
\er\- irregularK placed
at the tip id the
jiedicel from which
they spring. So
strange are the\- that,
when hrst seen under
the microscoiie, one
finds it hard to realise
that such structures
are lurirs. Vet the\'
are so. and to their
presence on a plant is due
beaut\" that \se see so clearl)-
for tlie\' often grow in such
dense masses and are so soft,
\\x)f)ll\', silky or scaly that a
thick network, '"felt" or
" dow n " is formed, and this
\\o\en, silverv-white dress, on
the surface of many leaves and
other plant organs, is some-
thing really charming to
behold. The wanderer on a
lone tract of open salt marsh
stands entranced — if he be
either botanist or artist — at
the glor\- of a mass of Sea
WormvNOod, decked in sil\er\

Front \'ie\v.

1-"igci;e 2.
Stellate Hairs from the leaf oi White Aral

much 1)1 the external
with the naked eye.

sheen, glistening in the sunshine, yet equall\'
exquisite in shadow . The beauty of this plant lies
in its "felt-like"' co\ering, every particle ot which
is made up of stellate hairs ! Our garden
Lavender (see Figure 3) is covered with a
gre\ish " bloom '" b}- which means the foliage
forms such a perfect setting for the lilac of
the blossoms. Every atom of this '"blocim"" is
nothing less than mvriads of charming stellate
hairs, branched and simple, springing from
the leaf epidermis on short, rather thick
pedicels. Some of the rays are long, others
short, mid all are more or less sharp-pointed.
In the I\-y (see Figure 4) each hair has from
three, to nine rays, brancheci or not, and
distinctly broad and flat, each ray springing
from the top of a long stem. I'igure 2
showing illustrations frorn the leaf surface
of garden white arabis, brings before us some
of the quaintest stellate forms of which it is
possible to cc)ncei\e. x\ front view of such a
hair has rather the appearance of a set of
stag's antlers, \\lnlst a side view looks rather

like a tree with trunk
and branches. If the
leaf of .\rabis be
examined, its surface
will be found to be
\er\' rough : this
roughness is caused
bv the hairs upon it,
and it is easy to realise
\\h\- the leaf should
lie so scabrous when w e
tind what remarkable
hairs grow all over it.
Apparenth' in different
plant species the num-
ber of rays tin each
hair differs to some
extent, though taken as
a whole the number ranges between three and fifteen.
One large natural order of plants, the C"ompositae,

Side \'ie\v.

Stellate Hairs from the
428

Front \'ievv.
iMCl'i;!-; .1.
■ felt " on the leaf surfaces of Lavender.

November, 1911.

KNOWLEDGE.

429

possesses a number of species specialh- noted for the
■■ felt " on the under-surfaces of their leaves, stems,
and so on. If only one be selected for e.xamination,
say the pretty little Mouse-ear Hawkweed, this one
plant will afford much that will interest us, for the
starfish-like hairs which form the "" felt " are the
most fascinating' objects. Figure 1 represents some
of them from the involucral bracts of the flower-
head, but the lea\'es and stems of this plant art- also
covered with thi' same i)rett\- silver\- structures.

Front View.

Side View.

Figure 4.
late Hairs from the flower pedicels of I\\-.

and other lii\el\-

[eaves and stem of

amongst the Mallows : in the curious

and in a
1 iilants.

\ery delicate and ver\' chaste

examples may be found on the

HolK'hock

growths called '"Oak spangles" or "galls,'

great many other common garden and wi

It is difficult to say why hairs
should become " stellate," }-et one can
see that their form is well adapted
for the forming of "down" or felt-
like growths, whicli no doubt play
an important part in the protection
of plant-surfaces.

Strange as are the stellate, the
jieltate or shield-like are. perhaps, the
most curious of all the man\- different
hairs with which we meet. Their I''

appearance on a plant often causes
the surface on which the\- spring to look, and feel,
ver)- scurfy and roughh' scalw for which reason the
term " lepidote " has been given to such hairs,
the word " lepis " being another name for "scurf."

Such a hair as this grow, from the e[)idermis
of leaf, stem, and so on. in such a w'a\' tliat it is
attached to it b\- its centre, and projects on either

than this flatlN'-expanded, toothci. radiating peltate
hair, when seen under the microscojie.

Other plants show different peltate forms, such as
the Sea Bucktliorn. the paleae of many young ferns,
the Wallflower and many other cruciferous plants,
Cornel, and so on. Figure 5 illustrates one taken
from tile leaf of Wild Cornel, and this is exactly' the
same in form as a similar hair from the Wallflower
leaf. It is curious to note how masses of these low-
growing, expanded flat hairs deck the leaf-surface,
all more or less of the same size and height,
the splayed tijis almost ptiking into each other.

V. — iiri Jointed [h) Clup.i;ed Plant Hairs.
J(,)inted hairs, compared with other forms on
the whole, are by no means so common, \ct
the\- are met with in considerable numbers, and
may be very well seen on the leaves of Hedge
Woundwort and many of its allies in the large
Natural Order, Labiatae : in Common Fleabane,
Bugle, Mossy Saxifrage, Foxglove, Germander
Speedwell, on the plants from whence the
accomjianying illustrations have been taken, and
on the loose, hairy tissue on the surface of the
stigma in many of the Orchidaceae.

If a hair of this kind be examined it will be
foimd to show, at certain marked distances up its

length, peculiar swollen

joints that l(_)ok \-ery

much like a series of

knuckles, which seem

to lit into sockets, the

side

a horizontal wa\-, thus forming a kind of

shield or very flattened plate, which is membranous
in texture, built up of man\- cells, and either more or
less smooth and even round its margin, or cut up into
numbers of sharp, delicate teeth of man\- varying
lengths. It is owing to the presence of these
" plates " that man\- plants present a scaly, scurf}-
surface. One need but look at Figure 6, a hair taken
from the leaf surface of Blcafiiiiis. to understand the
reason for the leaf's lepidote appearance, nor can
one well wish to see anything more rich in form

Figure 6.

tiGURE 3.

Peltate Hair from tlie under siir-
Hair from tlie leaf of Cornel. j^ce of the loaf of Ehaf^iiiis.

latter being much more clearly noticed in some
instances than in others. The Purple Dead -nettle
(see Figure 8) shows interesting examples of good
jointed hair structures, which are extremeh- sharp-
pointed. Those on the stem of one of the common
garden species of Harpaliuni (see Figure 9) are really
(juaint-looking little things with their thickened
joints. cur\'ed. sharp tips, and remarkabh' rough
surfaces : indeed, imagination can almost liken them
to the claws of a crab ! Figure 10, representing a
hair from the stem of the Mouse-ear Chickvveed, is
one the prettiest of all. perhaps, for there is a
slenderness about it that is graceful, and the way in
which joint fits joint is beautiful. In the Pineapple
Sage (see Figure 7) are some glandular hairs, on the
\'eins of the leaves, and the pedicels of these are
distinctly pointed. When touched firmly, this plant
emits a delicious odour of pineapple (which probably

430

KNOWLEDGE.

November, 1911-

gives it its name), owing to the
secretion formed within the hairs.
Those people who have e\-er had
the handhng of Jerusalem Arti-
choke plants will know that their
leaves are extremeh" rough, but
'few of them know that this fact
is owing to the presence of count-
less m}riads of sharp-tipped,
jointed hairs that are, if any-
thing, even more rough than
those of the Harpaliiini. a plant
of the same natural order. It
needs but a microscojie to show
the bristling, scabrous upper
coats of these simple, jointed
structures, and we can then
easily understand wh\' the leaves

Figure 7.

Jointed Hair from the leaf veins of
Pineapple Sage.

Scented Geranium. It is owing
to the presence of these hairs on
this plant that we get the
delicious odour when the leaves
and stems are pressed, for the
hairs are glandular, but of so
distinct a form that they are
classed b\' themselves as the
"clubbed,"" Figure 11 clearh-
shows some from the stem of the
Geranium, and one can note the
simple {i.e.. unbranched), thick-
coated hairs, each of which is
just like a club standing up on
a curious swollen base. They
are verv pretty objects both in-
dividually and in the mass, and
perhaps the fact that they are

Figure 8. Jointed Hairs from the cal\x of Purple Dead Nettle. Figure 9. Jointed Hairs from the stem of Harpalinm.

feel so rough and unpleasant to the touch.
Clubbed hairs are \-er\- often known as
Clavate. or club-shaped, and are so marked
in their features that it is difficult to overlook
them even when they grow — as is often the
case — in compan\' with masses of ordinar\-
ong and simple, or other forms of hair\'
appendages. Some very nice examples ma\-
:ie seen in the White Campion and Pansy ;
in .\vens and the interior of Willow-galls,
and so on, but one of the best plants is the

comparati\"el\- iinccimnKm makes them all
the more interesting when we come
across them, as is often the case, uncon-
sciously: for \'ery often one kind of hair
is met with exclusively on a plant,
but at other times one nvdv suddenh'
come across another kind interspersed
just here and there, and no more. In
this uncertaint\" lies the charm of real
obser\"ation work, be it with the naked
eye or microscope.

I'IGURE 10.

Jointed Hair from the stem

of Mouse-ear Chiclvweed.

Figure 11. Chibl)ed Hairs from the stem of Scented Geranimi

Figure 12.

Jointed Hair from the edge

of Jerusalem Artichoke.

THE FACE OF THE SKY FOR NOVEMBER.

Bv W. SHACKLETON, F.R.A.S., A.R.C.S.

Thk Sux. — Oil the 1st the Sun rises at 6.54 and sets at 4.34;
on the jOth he rises at 7.4J and sets at 3.54. Siinspots and
faculae may occasionally be seen on the disc, but of late spots
ha\e been small, although faculae have been fairly conspicuous.
The equation of time is a ma.ximum on the 4th, the Sun being
16"' 21" in advance of the clock, thus making the afternoons
short and the mornings long. The positions of the .Sim's axis,
centre of the disc, and helio.graphic longitude of the centre are
gi\en in the following table : —

Mercury

THE PLANETS.

Date.

Axis inclined
from N. point.

Centre of Disc

N. of Sun's

Equator.

Heliographic

Longitude of

Centre of Disc.

Nov. 2

24° 33 '1'-

4° 13'

227° 37'

7 ■■■

23" 35'K

3" 41'

161° 41'

,, 12 ...

22'" 26' E

f 7'

95° 46'

,, 17 ...

21° S'E

2° 32'

29° 52'

22 .

19° 34' E

1° 56'

323" 5S'

„ 27 ...

17° 5i'E

1° 19'

25«° 3'

Dec. 2 ...

15" 59 L

0° 40'

192° 10'

7 ■•■

13" S7'E

0° 2'

126" 16'

The Moon :

Date.

rha.ses.

H.

M.

Nov. 6 ..

,, 13 ..

,, 20 ...

,, 29 ...
Dec 6 ...

0

•
])
0

Full Moon

Last Quarter ...
New Moon
First Quarter ...
Full Moon

3

7
8
1

2

48 p.m.
20 a.m.

49 p.m.
42 a.m.
52 a.m.

Nov. S ...

„ 24 ...

Dec. 7 ■■■

Perigee ..

Apogee

Perigee ...

6

4
1

12 p.m.

24 p.m

0 a.ni

i

There is an eclipse of the .Moon on the 6th, but as the
moon only passes through the penumbra of the earth's shadow
very little darkening will be observable; moreover, one will only
be able to observe the end of the eclipse and that under bad
conditions, as the moon will be low down. The particulars of
the eclipse are given below : —

Nov. 6
... I.31) p.m.
... 3.37 p.m.
5.34 p.m.
4.1 7 p.m.

the principal occulta-

First contact with the Penumbra
Middle of Eclipse ...
Last contact with the Fenumbra
Moon rises (at Greenwich)

OCCULTATIONS. — The following ari
tions visible from Greenwich : —

Dale.

Star's
Name

Disappearance.

Reapiiearance.

Mean

Angle
from N.

Mean

Angle
from N.

S

Time,

point.
E.

Time.

poult.

Nov. 7

32 Tauii

5'S

p.m.

7.23

14"

p.m.

7-57

299°

,, 10

47 Geminoruin...

5-6

—

-

7-36

306°

,. II

\ Cancri

5 '9

9-7

153°

9-35

219'^

„ 29

\p'^ Aquarii

4-6

9 15

So=

10. T 6

212°

Dec. 7

136 Tauri

4-6

1.46

19°

.i.m.
2. II

337°

Date.

Right Ascension.

Declinaiion.

Oct. 29 ..

Nov. 8 ...

18 ...

28 ...
Dec. S ...

h. m.

14 25

15 27
10 ;o
>7 33
18 27

S 14° 20'

S 19-' 53'
S 23° 4q'
S 25° 44'
S 25' 20'

Mercury is in the neighbourhood of the Sun at the beginning
of the month, but towards the end of the month the planet
becomes an evening star in Scorpio, setting at 4.42 p.m. on
the 27th November.

Venus: —

Date.

Oct. 29

Nov. S

„ iS

28

Dec. S

Right Ascen.sion.

h.

m.

n

28

1 1

59

12

53

n

1 1

Declinaiion.

N

2°

3

N

0°

20

.S

2"

15'

s

5"

2S

s

8"

i2'

Venus is a morning star in Virgo, and is at greatest westerly
elongation of 46° 45' from the Sun on the 26th. when she rise's
E, by S. at 3.5 a.m..

The planet appears as a very conspicuous object in the
morning sky looking east. The apparent diameter of the planet
is about 30", whilst 0-5 of the disc appears illuminated ; thus
the telescopic appearance is that of " half moon."

Mars ; —

Date.

Right Ascension.

Declinaiion.

h. m.

Oct. 29 ...

4 34

N 21° 49'

Nov. 8 ...

4 2S.

N 21" 58'

,, 18 ...

4 Q

^' 21° 53'

,. 28 ...

3 53

N 21^' 37'

Dec 8 ...

3 39

N 21° 16'

Mars is a very conspicuous object in the S.E. portion of the
evening sky. where he appears as a very bright red star a few-
degrees to the South-east of the Pleiades. The planet is
visible throughout the night, as he rises about sunset and sets
about sunrise. The planet is in opposition to the Sun on the
25th, when he appears due South at midnight. This opposition
is a very favourable one as regards the altitude of the planet,
though not so favourable as regards nearness to the earth,
compared with oppositions in 1907 and 1909. The planet's
altitude on this occasion reaches 60° when on the meridian,
whilst the apparent diameter of the disc is 18", corresponding
to a distance of about 481 million miles. Below is given a
table showing the altitude and comparative distance of several
oppositions : —

Opposition.

Declinaiion.

Allilude.

Relative Distance
from Earth.

1 505
1907
1909
I911

S 16 57'
•S 27 1'
S 4 11'
N 21' 42'

21 r

Hi'
34"
61 =

0537
0408
0-390
°'Si7

431

432

KNOWLEDGE.

November, loll.

The latitude of the planet's centre is — 10% hence the
southern hemisphere is inclined towards the earth, and is in the
best position for observation ; but little of the snow cap is
visible as it has dwindled to small dimensions in the advancing
summer of the Martian Southern Hemisphere. The dark
markings, according to Lowell, should, during the summer of
the hemisphere under observation, be increased in intensity.
In telescopes of 3 or 4 inches aperture the dusky markings on
the disc are observable when the seeing is good. The time of
rotation is 24'' 37" 23^ appro.ximating to that of the earth, so
that the same regions may be scrutinized on successive
evenings. The well-known marking of the Syrtis Major is
visible on the 12th about 10 p.m., and the Soils Lacus on the
2Sth at 9 p.m. The two small satellites, Phobos and Deimos,
are only visible in the largest telescopes.

The moon appears near the planet on the morning of the
Sth,

JUPITER: —

Date.

Right .Ascension.

Declination.

h. ni.

Oct, 29 ..

'5 14

S 17" 11'

Nov. S ...

15 23

-S 17° 45'

„ 18 ...

15 32

S iS" n,i'

„ 2S ...

15 41

.S iS" so'

Dec, 8 ...

15 50

S 19" 20'

Jupiter is in conjunction with the Sun on the ISth, after
which he becomes a morning star: during November, however,
he is practically unobservable, being lost in the Sun's rays,

Saturn : —

Date.

Right Ascension.

Declination.

Nov. I ...

., 16 ...

Dec. I ...

b. m.

3 3
2 58

2 53

N 14" 35'

14° 15'

N 13" 58'

The apparent diameters of the outer major and minor axes
of the ring system are respectively 47" and 17". and we are
looking on the Southern surface at an angle of 21°, so that the
ring appears open. The diameter of the ball is IS". The
ring is visible with a power of about 50, and the belts with a
power of iSO. The moon appears near the planet on the
evening of the 6th.

Ur.^nus : —

Saturn is a very conspicuous object in the evening sky,
rising E.N.E, immediately after sunset. The planet is about
15' to the West of Mars, and the two bright planets form a
striking pair,

Saturn is in opposition to the Sun on the lOth. and thus is
due South at midnight about this date.

The telescopic view is splendid, as the rings and belts are
readily seen even when seeing is comparatively poor. In
addition to the ring, the belts on the disc and also some of
the numerous satellites may be observed. A telescope of
three inches aperture is sufficient to show the four larger
satellites, namely, Titan, Japetns, Rhea, and Tethys, Titan
is generally to be looked for at a considerable distance from
Saturn, not only to the sides, but also apparently above and
below the planet.

The division in the ring may be seen in a good telescope of
two inches aperture; whilst the dark ring requires an aperture
of four inches, with good atmospheric conditions.

Dale.

Kigbl .A.sceiiiion.

Declination,

Nov. 1 ..
Dec I ...

b. m. s-
19 51 4
19 55 -3

S 21^ 33' 4"
.S 21" 20' 53"

Uranus is unfavourably placed for observation on account
of his low altitude. He is situated low down in the S,\\',
portion of the sky at Sunset, and sets at 8,30 p,m, on the 15th,
The planet appears in Sagittarius, in a part of the sky devoid
of good reference stars, though the star f Sagittarii is about
5° to the N.lv.

Neptune

—

Date.

Right .Ascension.

Declination.

Nov. I . .
Dec. I ...

b. m. s.
7 42 16
7 40 55

N 20° 47' 6"
N 20-' 50' S"

Neptune rises about 8.30 p.m. near the middle of the
month and crosses the meridian about 4 a.m. Thus he will
be in a better position for observation a few months later.
The planet is located in Gemini, nearly midway between
68 Geminorum and 'P' Cancri.

Meteors. — The principal meteor showers during the month
are the Leonids and Androinedids : —

Date.

Radiant.

Characteristics.

R.A.

Dec.

1

Nov. 14-16 .
„ I7-23-

b. m.
10 0

I 40

-f-22"

+ 43"

Swift, streaks.

(Great Leon iii shnver).

Very slow, trains.

(Grea/ Androiiiedid shower).

1

.Algol will be at miniinum on Nov. 1st at 11 p.m.. 4th at 8
p.m., 7th at 5 p.m., 24th at 9 p.m, and 27th at 6 p,m. The
period is 2'' 20"^ 49"' from which other minima may be deduced.

Telescopic Objects : —

Double Stars, — rj Cassiopeiae O'' 43'", N, 57° 17', mags,
32, 7i ; separation 6"-l. Binary star,

\ Arietis l" bl"', N, 23° 6', mags, 4, 8: separation 37".
Components white and blue; easy with power 20.

') Persei 2" 44'", N. 55° 2s', mags. 4, S: separation 28",
The brighter component is orange, the other blue. There are
also several other fainter stars very near.

QUERIES AND ANSWERS.

Readers arc invited tu send in Questions and to ansiver the Queries which are printed here.

QUESTIONS.

54. I have a copy of the Nautical Almanac for 1911, and
monthly compare the results given in '" The Face of the Sky ''
supplied by Mr, Shacklefon, F,R,.-\.S.. and have often wished
that I could so correct the tables as to make them applicable
to any place other than Greenwich.

Will you kindly enlighten me through your columns on the
following : —

Url What is the formulae to obtain the inclination of the

Sun's axis from the W. point ?
(/)! \\ h.it is the fonimlae to obtain the heliographic
latitude of the centre of the Sun's disc :

Xi)\i;mi!ER, 1911.

KNOWLEDGE.

433

(cl \\'hat is the formulae to obtain the lieHographic
longitude of the centre of the Sun's disc ?

Also : — Is there any way that I could apply the difference
in time between Greenwich and Sydney to the tables of the
Xaiitical Almanac, pages 513 and so on, showinj; position of
Jupiter's satellites, so that the\- would be shown as they would
appear at Sydney ?

In what publication lor iiublicationsi could I find the
formulae known as " Lcuschner's Slimt Method " of comput-
ing comet orbits ?

CKNTAUKL'S.-

ANSWERS.

44. COLOURS OF THE SPECTRUM.— The green p.art
of the spectrum cannot be divided into yellow and blue ; other-
wise, as the querist suggests, the prism would fail to produce
a green band. The only effect of using a prism to split up the
green part would be to magnify that part, as it were, by show-
ing more gradations of green.

The term " Primary Colour " does not mean " A colour
incapable of analysis into others"; the "Primary Colours"
are those sensations out of which all other colour-sensations
are built, according to Helmholt^' theory. For instance,
though yellow light may have a definile wave-length, when it
strikes the retina three distinct sets of nerves respond, in such
a proportion as to give the sensation of yellow-. Other colours
excite them simply in different proportions, and the colours
which excite only one set of nerves at a time are called the
Primaries. They are a certain red, green and blue. But,
although the sensation of yellow is made up of a mixture of
three sensations, it does not follow that yellow liglit can be

split up into three differently coloiu'ed lights.

C. N. F.

44. COLOURS OF THE SPECTRUM.— The green
region of the spectrum cannot be resolved into yellow and
blue. Every part of a continuous spectrum has its own
particular wave-length, and any very narrow portion of it may
be considered as appro.ximately monochromatic. The colours
of the spectrum, when produced under proper conditions,
(such as with a narrow slit, and so on), are pure ; and it is
important to distinguish clearly between such colours and the
subjective tints which can be producd to imitate them by the
proper blending of rays of other colours. On page ten of the
new edition of Professor R. Wood's treati.se " Phj'sical
Optics," there is the following I'eference to subjective colour :
" The colour depends upon the wa\e-length, but colour caimot
always be taken as an indication of wave-length, as ceitain
colours can be imitated by the simultaneous action upon the
retina of two trains of waves, either of which acting alone
would give rise to a totally different colour from that
perceived when both act together." [The italics are mine] .
" For example, a yellow scarcely distinguishable from the
yellow of the sodium flame, can be produced by a mixture of
red and green light in proper prc)|)ortions."

Ch.arles W. Rahi;tv.

45. HEAT AND A VACUUM.— Heat can traverse a

vacuum in the form of radiant heat, which has the property

of being reflected by polished surfaces ; thus the heat emitted

from the inner vessel in a vacuum flask is sent back by the

inner surface (polished) of the outer case; of course, some

may be again reflected, back and forward, and it is to be

remembered that at each reflection there is a slight loss ; but

at any rate, all the heat emitted is not lost, only that which is

reflected an even number of times and then absorbed. If the

space contained air, however, the conducting power of the air

layer would carry heat to the case, gi\-e it up to the case, and

so cause a continual loss, ,- ,. ,,

L . N. r .

50. (31 RADIO-ACTI\TTV.— It is generally considered
that the glow ("luminescence") of the glow-worm is due to a
process of oxidation. The light-giving organs consist of two
layers. The inner one is of an opaque whiteness, and is
possibly protective and reflecting; the outer is semi-transparent
and of a slight yellow colour.

Between the two layers is a network of very fine trachae,
which, it is presumed, supply the necessary air to the substances
the oxidation of which results in the production of light.

The light of many Lampycidae. especiall3' those out here, is
regularly intermittent, i.e., the light appears for, say, two
flashes, and then ceases for the time of four flashes of equal
duration; others are three to one : but the causal mechanism
is, I beheve, unknown. l. G. Gilpin-Brown.

50. RADIO-ACTIVITY.— (1) It is now accepted that the
a particles emitted by radio-active elements are atoms of the
gas helium. In the case of niton (radium emanation) this is
capable of spectroscopic verification.

Such processes may be regarded as spontaneous trans-
formations of substances which we ha%e every reason to
consider as elements.

(2) The X-rays and the 7 rays from radio-active substances
may be considered as closely similar types of radiation the
actual nature of which is very uncertain. Many eminent
physicists favour a pulse theory, — i.e.. one which supposes
the radiation to be composed of very thin pulse-shells in
which the wave-front is not uniform but nucleated ; and that
such pulses are due to the negative accelerations (X-rays), and
the positive accelerations (7 rays) of swiftly moving electrons.
Other investigators favour the view that both types are
corpuscular, being composed of neutral pairs, and hence
not deviated by magnetic or electrostatic fields. We may
reasonably hope for more definite knowledge in the near
future.

(3) The light of the " glow-worm " is believed to be due to
the active oxidation of a peculiar photogenic substance pro-
duced by the insect. Experiments support this theory.

Ch.arles W. Raffktv.

REVIEWS.

CHEMISTRY.

Chemistry lu the New Edition of the Encyclopaedia
Britanuica.
The requirements of an article upon a particular science in
a general encyclopaedia are. firstly, that it shall be easily
understood by an intelligent reader who is practically
unacquainted with the subject; and secondly, that it shall
contain a full bibliography to which the expert can refer for
directions where to find what he wants. The chemist, for
example, will not want to use the Enc\clopaedia as a text
book, while the average general reader will be repelled b\-
pages of mathematical formulae which are appropriate enough

in the text book. -Any attempt to satisf\- both classes of
reader will inevitably fail to satisfy either.

Judged by this criterion, the new edition of the
" Encyclopaedia Britannica," marks a great advance upon the
previous edition. As instances of the way in which the
chemical articles meet these requirements, we may cite those
upon " Elements," " Colour " and " Fluorescence," which any
educated person can follow. The general article upon
"■ Chemistry." admirabl>' written as it is, errs somewhat in the
direction of the text book.

In most instances, the subject matter has been brought well
up to date. For example, the latest details on metallography

434

KNOWLEDGE.

NOVF.MBEK, 1911.

are given, and excellent photnniicn),i;r;iplis accompany the
article on "Alloys."

It is. perhaps, in the biographical articles that the
Encyclopaedia will fill the greatest gap in the library of the
chemist. This portion of the work has been fully dealt with,
and in a manner that leaves little to be desired.

C. .\. M.

GEOLOGY.

The Coast Scenery of Nortli Devon. — By E. A. Xewell

Arber, M..-\. 261 pages. 63 plates. 11 figures. 2 maps.

9-in. X 6-in.

(J. M. Dent & Sons. Price 10 6 net.)

Mr. .\rber is a distinguished palaeobotanist. but in the
intervals of his researches has found time to write this fine
monograph on an exceedingly interesting and beautiful portion
of our coast. In an introduction the general geology of the
area is described. The country is built of highly plicated
slates, sand.stones and shales of Devonian and Carboniferous
age. Two types of cliff, the " flat-topped," and the " hog's
bacU " are distinguished. Whilst the former represents the
effect of sea-erosion on a flat tableland, the latter is far more
complex, and its origin is left in doubt. One of the special
features of the coast-line is the fine series of coastal waterfalls,
which are naturally most conspicuous when falling over the
"flat-topped" type of cliff. An excellent section on "beach-
scrambling" gives one the impression that it is a sport quite
as exciting, if not as dangerous, as mountaineering.

Part 1 describes in detail the six districts into which the
coast-line is divided. For each district full directions are
given as to suitable headquarters, ways of reaching the cliffs,
and the necessary maps. Part 2 deals with the special
features of geological interest along the coast. The somewhat
neglected subjects of the marine erosion of folded rocks, the
evolution of coastal waterfalls, and sea-dissected valleys, are
dealt with, and the author claims, and claims justly, original
value for his work. This part forms a valuable contribu-
tion to the study of scenery. Mr. .Arber shows that the
intersection of the plane of marine erosion with a m.aturely
dissected country must result in headlands and bays — the
former corresponding to the watersheds, and the latter to the
valleys — which have no relation to the differential hardness of
the rocks involved. Whilst the latter may sometimes control
the larger features of a coast, as in Pembrokeshire, more usually
it merely determines minor irregularities.

A good bibliography and index is given, and the book is

illustrated by a series of fine plates. The reader may be

perplexed by the absence in some of the plates of any means

of estimating the scale of the view shown. The author is to

be congratulated on this book, which will be useful to both

geologist and geographer. The best compliment we can pay

it is to hope that it may be the precursor and model of many

similar works. .p

( I. \\ . i ,

.me:teoroloGtY.

British Rainfall, /!?/r*.— Edited liy Hugh RniiEKT Mill.

Director of the British Rainfall Organization. 440 pages.

65 maps and illustrations. 8i-in. X 5i-in.

(E. Stanford. Price 10 -.)

The British Rainfall Organization is an organization of
voluntary and unpaid observers of Rainfall, nearly five
thousand in number, resident in all parts of the British Isles.
The work was established by the late G. J. Symons, F.R.S.,
and it is being ably carried on by his successor. Dr. Mill.

The volume for 1910 is the fiftieth of the series, and it is
interesting to note that four of the observers who contributed
to the first volume in 1861. also contribute to the volume for
1910. The volume for 1861 contained records from four
hundred and seventy-one stations, that for 1910 contains
records from four thousand eight hundred and seventy fom-
stations.

Although primarilva volume of statistics tin; book will prove
of great interest to very many who care but little for figures.

The excellent maps which illustrate the distribution of rainfall
over the United Kingdom, both in time and in space; the
observers' notes upon exceptional weather experienced by
them, and the discussion of heavy falls of rain, hail and snow,
should prove interesting to all. Dr. Mill contributes an article
upon " The Rain Gauge in Theory and Practice." which is pro-
bably the final word upon the subject.

In addition to yearly results for nearly five thousand
stations there are monthly tables for three hundred carefully
selected representative stations, .and daily values for ten
stations.

The Rainfall for 1910 varied between 19 -44 indies at Ropner
Park. Durham, and 187-06 inches at Llyn Llydaw Copper
Mill. Carnarvonshire. J. .A. C.

NATURE STUDY.

Garden and Plaviiroiind Xature Study. — By J. E.aton
Eeaskv. 184 pages. 65 illustrations. ' 5-in. X7|-in.

iSir Is.aac Pitman and Sons. Price 2/6 net.)

Mr. Feasey has already produced two volumes dealing with
school work that should be done in the open air, but in his
introduction he expresses the conviction that the work and
methods advocated in the present volume will be more valu-
.able even than the set lessons which were contained in the
others, and will surpass them from the point of view of real
education. He quite rightly emphasises the fact that Nature
Study should not deal merely with animals and plants. His
first lesson, entitled, ".A Trap to Catch a Sunbeam," is a com-
parison between two thermometers, one of which is kept under
a bell jar. The lessons on dew, shadows, and the laws of
reflection, as well as those on the weathercock and on snow,
follow out the same idea ; but " bloom," " the sleeping and
waking of plants," and on " being irrit.able " deal with the
botanical side of Nature. Many of the illustrations are good
and it is obvious that they have been made on purpose for the
book. Mr. Feasey goes into considerable detail as to how the
lessons are carried out, and we may say at once that every
teacher of Nature Study will gain something by reading this
book.

W. M. \V.

'HYSICS.

The Radiation Theory of Light and Color. — By Mrs. \.
RoGERS-MooRE. 7S pages. 21 illustrations. 9i-in.X6-in.

(U.S.A. The Stratton Press. Inc.)

.A refutation of the Composite Light Theory of Newton.
" To refute the Composite Theory, declared itself as the last
necessity, not as incentive of color expression in nature .
The radiation theory has been evolved from the single desire
to know the cause of the pink petal of a rose. . . . The
work ended with a refutation of the Composite Theory as we
have stated. . . . Let no condition of sunlight be lost
therefore ; if possible, let the observ.ations be continued for
years ; as these have been to establish the Radiation Theory
of Light and Color Formation."

Such is an extract from the Preface. It appeared promising !
Later on : " Light and Color are the result of molecular motion
of the air. . . . Light is the greatest air velocity which the
eye recognizes. . . The spectrum is not any more spectral
than any other colors and is just as natural." Finally : " It
does not seem too much to assume that light rotates and pushes
all ether and all the constituent parts of the air. In other
words : the sun creates tlie world and everything on it. But
not without a guiding hand."

I think .after these quotations from the pamphlet a review
is not of further necessitv.

A. C. E.

ORNITHOLOGY.

The Voiing Ornitliologist : .A guide to the haunts, homes
and habitf. of British Birds. — By W. Perciv.^l We.STELL,
F.L.S.. M.B.( ).U.. .\ulhnr of " The Young Naturalist," "The

November, 1911.

KNOWLEDGE.

435

\ oui)!,' Botanist." 311 pages. With a frontispiece in colour,
and sixt3'-five photographic ilhistrations. 7iin. X 5-in.

(Methuen and Co. Price 5,-.)

The title expresses tlie intention of tliis book, and tlie author
writes with abundant vi\acity and \igoiir. Young readers
will hud him to be a sympathetic and friendly adviser. For
their edification he has " mapped out " the birds described
according to their natural haunts, and this is put forward as
the chief feature of the book. There are chapters on the
birds of the garden, the country lane, the woodland, the water-
side and so on. Such a division is fairly useful, and can be
understood, but it is so far from being definite that it may be
doubted if it is of any great value. No animals are less circum-
scribed in their bounds than birds and any arbitrary division
is sure to require much explanation and qualification. Many
species vary their habitats ; this is illustrated, for instance,
by Mr. Westell placing the Common Curlew and the Whimbrel
both in the chapter on the birds of the moor and in that on
the sea-shore. Correctly so : and this double -placing might
have been extended to other birds also. The arrangement
chosen makes queer neighbours, e.g., the Woodlark is
immediately followed by the Partridge and the Quail by the
Stone Curlew.

Plenty of information and vivid descriptions are given
of the different species, and the style of writing is
certainly likely to prove more attractixe to young readers
than to others. Occasionally the author allows himself to
lapse into errors such as occur when he speaks of the
Brambling (page 16.S) as nesting in the British Isles, and the

Snow Bunting (page 224), as breeding in England; and the
statement that the Gannet breeds on '"several groups of islands
on our western shores'" (page 271) is a generalization that
requires serious qualification. On the other hand, the Fulmar
Petrel (page 286> is not now restricted to St. Kilda and the
Shetlands, having recently considerably extended its breeding
range, and the Little Bittern (page 243), like the Common
Bittern, nested in England at one time. The bird figured in
the coloured frontispiece by Mr. G. E. Lodge, as the "" Bittern
at Home"" is referred to in the text (page 242) as the Little
Bittern; but "it seems clearly to represent the Common
Bittern. The remark that one hundred and thirty Heronries
are still in existence (page 242) is not said to apply to England
only, but in Ireland more than three hundred Heronries are
known, and in Scotland about two hundred and twenty, at
present. The photographs throughout the book are ex-
cellent, more particularly when their necessarily small scale
is considered.

The first part of the work (and it perhaps ought to have been
mentioned first here) is by Mr. A. R. Horwood. of Leicester
Museum, running to seventy-eight pages, entitled. "" Hints for
the Young Ornithologist,'" on observing birds, collecting, field
work, and so on. This is an admirable and thorough
production, and the bird-boy who can assimilate these hints
and act upon them, will approach perfection. He will
demonstrate that, while the interests of the British boy (even
in bird-nesting) are of more importance than those of the
British bird, yet the bird, too, has its rights, which should be
fully respected. „ j. ti-

FLKillT .WD FLVlXCx
IN THE " ENXYCLOPAEDIA BRITAXXICA."

The article under this heading is distinctly disappointing,
and although the casual reader may find some pleasure in
studying the in\estigations of Pettigrew. De Lucy, and others
into the action of birds' wings, and so on, the modern student
would rightly expect something more up-to-date in the latest
edition of a work which claims to be abreast of the times.

Certainly there is some slight mention of the machines of
the Wright Brothers and Santos Dumont. together with photo-

graphs of the Farman. Bleriot, and Roe machines, but there
is no description of these later, nor is there one word about
the modern theory of Flying Machines, which, even after
making allowances for the exigencies of publication of a large
work, must ha\e been \ery well ad\anced at the time the
article was written.

In short, there is nothing in the article of the least possible

"se. T. W. K. C.

A METHOD (BELIEVED TO BE ORIGIXAL^ OE DI\TDIX(^z AXOxLES
OF 4-y OR LE.SS IXTO THREE EQUAL PARTS.

Bv C. S. BINGLEY. F.(.M.S.

Let B A C be the angle to be divided :

From the point A, mark or describe the arc B C

Bisect arc B C (D)

From D draw the line D A

Bisect line DA (E)
Draw lines E B : E C
Bisect lines E B ; EC
Draw lines D F ; D G
Bisect lines D F ; D (i
Draw lines EH: F! I
distances B J ; J K ; K C
the arc B C divided into
drawn from the points J
divide the angle B A C
J A K ; K A C

(F G)

(H II

Continuing to J and K : the

, will all be equal and, therefore,

three equal parts, so that lines

and K to A (J A; K A) will

into three ecjual angles, B .\ J ;

Figure 1.

[Any inaccuracy is due
to error in the drawing

NOTES

ASTRONOMY.

By A. C. D. Crommf.i.ix. B.A.. D.Sc. l-.K.A.S.

FIGUKH OF THE SUN.— B»//c/'/h Astronomiqiic for
September contains an interesting article on this subject by
Father Chevaher, S.J.. of the Zo Se Observatory.

The investigation has been carried on by photography :
only plates on which the limb is sharp have been nsed. A
great many possible sources of error, such as imperfection in
the refraction connection, deformation due to the objective,
tilt of plate, diffraction, and so on. produced by the exposing
slit, have been examined, and it is claimed that the precautions
taken have practically eliminated their effects from the
measures. The surprising result emerges that for the five
years 1905 to 1909 the polar diameter of the Sun is longer
than the equatorial one, the figures being as follows : —

Excess of Pol.ir Nunilier of

Year. Diameter. Prolinljle Ennr. Pl.'Ues.

1905 0"-07 ... 0"-05 ... IfiO

1906 0"-17 ... 0"-04 ... 27.S

1907 0"-Jl ... (f'-OJ ... 4^1

190S n"-_'9 ... ()"-()4 ... 320

1909 0"-lJ ... ()"-()2 ... 53(1

General Mean 0"-20. with Probable luror 0"-i)15.

It will be noted that in every year the Polar Diameter ex-
ceeds the Equatorial by an amount greater than the probable
error. It is also noteworthy that there is a sort of sequence in
the figures. The excess moves steadily up to a maximum in
1907, which is the year of sunspot maxinuun. and then steadily
falls off. The results for 1910 confirm the falling off; ninety-
six photographs taken in April and August give + 0"-05 ; one
hundred and two in September and October give— 0"- 05.
There is certainly room for the suggestion that the sun's figure
may change periodically in the sunspot period, which would be
a result of great interest and significance. Dr. Chas. Lane
Poor had already, in 1905. announced his suspicion of such a
variation, from measures of photographs taken by Rutherford
and Wilson. Father Chevalier is doubtful, however, whether
the same precautions were taken in that series of photographs
as in the present one, and is inclined to give it less weight.
The fact of the Polar diameter exceeding the Equatorial one
had been deduced by Dr. Auwers and MM. Schur and
,\mbronn. In fact, it appears that any long series of observa-
tions, however taken and however discussed, will yield this
unexpected result.

MR. BARTKUM'S THIRD OUERY.— (August number,
page 311). — The fallacy lies in considering the average value
of r for equal time intervals. What we want to consider is
the average value of disturbing force for cciual time intervals.
The Sun's whole action on the Aloon varies inversely as the
square of his distance, but his differential or perturbing action
varies inversely as the cube of the distance. It can be shown
that both the whole action and the differential action are
greater for a more eccentric orbit of the Earth round the Sun.
A simple geometrical proof for the whole action is given in
Proctor's "Saturn and his System," First Edition, page 167.
Consider two elliptical orbits with the same semi-major axis a.
but with different semi-minor axes b, b', b being the greater.
The periods (which depend on a) are equal. Let each planet
be at the end of its minor axis, then each is distant a from the
Sun. The areas of the orbits are as b to b'. and this is also
the ratio of the rate of description of areas, since the periods
arc e(iual. Now consider a very small interval of time from
the moment when each planet is at the end of its minor axis.
The small area swept out by each =A a' X angle swept out at
Sun. Hence the angles swept out at .Sun are .is b to b'.
Now considering either planet .it .any |)oint of its orbit, the

gravitational attraction is , and the sum of the action in time

f M
t= / ^j-dt. .Also from the equ.al description of areas

dt = k d .A, where d .\ denotes an element of area and k is a
constant. And dA = j r" dl> where dS is the small angle swept
out at the Sun in the interval dt. Hence the whole gravita-
tion.al action in time

d"

Mk^
2 .

Thus the action varies as the angle swept out. Now, return-
ing to our two planets, the gravitational actions in the small
interv.al of time considered are equal, since the distances
from the Sun are ctjual. Thus action in whole revolution

= action in small int(-r\al X r, t- But we have seen

small angle

swept out.

that the small angles swept out in the interval are as b to

b' ; hence the gravitaticJnal actions in the whole revolution are

as b' to b, or the action is greatest in the planet with smallest

b or greatest eccentricity. Hence, as the earth's orbit becomes

less eccentric, the total action of the Sun on the Moon

diminishes. The differential action diminishes also. For this

k'
— dt

k

dt_
r'"

7^

= / — d»

Ik', k" denote constants). Now in an ellipse r

hi'uce
k" e

drt =

■ k" (1+e cost))

dt)

1+e cos 0

cos H d ti.

a d-e'") a (l-e'-)

Nou'. on integrating through four

ad— e-17

right angles the second term vanishes and the total differential

action of the Sun in a year = -^-^ — .,,. .^s c diminishes this

a (1 — e"'

action also diminishes, .and tlir Moon approaches the earth

and moves faster.

COMET NOTES. — Brooks' Comet will be a morning star in
November, but not very easy to see. owing to its approach to
the-sun.

The following is an ephemeris for 11 p.m. : —

R.A.

S.Dec.

Nov.

R.A. S.Dec.

M M. S.

Nov. 16. ..13 0 17 18' 3'

„ 20. ..13 9 45 21° 28'

4. ..12 37 43 4' 57
8. ..12 43 5(> 9" 49'

., 12. ..12 51 38 14- 10'

Two other comets were discovered at the end of September
that of (Juenisset was of magnitude 7, thus being an easy
telescopic object; that of Beljawsky would have been a very
fine object on a dark sky, but it could only be seen low down
in the twilight. Neither comet will be well placed for obser-
vation in November, so we simply give elements without
ephemerides.

Ouenisset. Beljawsky.

T 1911, Nov. 12-67 (Berlin) 1911. Oct. 10-30 iBeriinl

u 123° 24' 71° 39'

<.' 35^ 37' 88 44'

c 108" 13,' 9(j° 38'

Logq. 9-8897 9-4823

The orbit of (juenisset is very like that of Comet 1790 III.,
discovered by Caroline Herschel.

TH1-: NEW FRI-.NCH TABLES OF THE MOON.— The
appearance of new lunar tables is an important epoch in exact
astronomv. It is about half a century since the appearance

436

NOVF.MBEK. 1911.

KNOWLl-.DGE.

437

of Hansen's tables, which were an immense improvement on
all that preceded them ; they were considered, in the words of
Sir John Herschel, '" As a practical completion of the Innar
theory, at least for the present age. and as establishing the
entire dominion of the Newtonian theory and its analytical
application over that refractory satellite." These high
expectations were doomed to some disappointment ; in a few-
years the errors of the new tables became serious ; an
examination of the cause was made by Professor Newcomb ;
he found that the main part of the error was due to Hansen's
Venus terms : the one of two hundred and thirty-nine years
period should be omitted altogether, and that of two hundred
and se\enty-three years seemed to need an alteration of phase.
N'ewcomb further reduced the secular acceleration from
12"- IS to 8"-42. Hansen supposed he was using the theore-
tical value, and also that indicated by ancient eclipses, but
Adams showed that the \alue really given by theory was onl\-
6". and a more careful study of the eclipses showed that the\-
were better represented by 8" or 9". Newcomb further
showed that in consequence of his changes the motion of the
moon in a century must be reduced by 29"- 17. His
correction to the two hundred and seventy-three year term
was an empirical one (this expression denotes a term derived
from observation alone, without any known basis in theory).
It had a coefficient of 15^" and a period of two hundred and
seventy-three years like the Venus term. All who have
studied the moon's motion have found the need for such a
term, though they differ about its exact size and period.
Newcomb's corrections, which were introduced in the Nautical
Almanac in 18S3. were a .great improvement on Hansen :
the objection that some people made that thej- introduced
empiricism into astronomy was not a fair one ; Hansen's
tables were themselves empirical as regards the erroneous
Venus term, which has no basis in theory ; three of New-
comb's four corrections brought Hansen nearer theory than
before, only the fourth was empirical. In recent years the
moon's place has begun to deviate considerably from Hansen
corrected by Newcomb. so the need of new tables has been
felt. The great French astronomer Delaunay was engaged on
his lunar researches at the same time as Hansen, but in a
different manner. His idea was to find al.gebraical expressions
for all the terms as functions of the elements of the solar and
lunar orbits. The advantage is that the effect of a change in
the adopted value of any element can at once be deduced,
also that the investigation serves for other satellites, provided
their eccentricities and inclinations are not too great
(they break down for the new satellites of Jupiter
and Saturn). The drawback is that the expressions
do not converge rapidly, and that even after com-
puting a very large number of terms, he had reason
to fear that those of higher orders were still sensible.
Delaunay was unhappily drowned at Cherbourg in
1872, when the theoretical work was nearly com-
pleted, but the preparation of tables scarcely begun.
These long remained in abeyance, till the Bureau
des Longitudes took up the matter, and it has now
been concluded with the help of the late Professor
Tisserand, MM. Schulhof. .Andoyer and others. It
is not a blind following of Delaunay, whether
right or wrong, but advantage has been taken of
the work of Kadau, Brown. Cowell. and others, to
correct and supplement those terms that seemed to
be defective, if necessary carrying Delaunay's de-
velopments to a further approximation ; this has
been done chiefly by M. Andoyer. The new tables
diminish Hansen's mean motion by 27" per century,
and his acceleration by 4"-4S, making it 7"- 7.
Instead of Newcomb's empirical term of two
hundred and seventy-three years, they introduce
the following two empirical terms :

of tiny planets circulating rou:.d the sun at a distance
about 0-178, period 27-3 days, almost the same as
that of the moon. If the total mass of the swarm was
one-fifteenth of that of Mercury, that is one-third of
that of the moon, there would result a term in the
moon's longitude with coefficient 12", period two hundred
and seventy years." Other positions of planets are also given
which might produce such a result. It is a striking instance of
the possible importance of small masses when their periods are
almost commensurable with other periods. It will probably be
of general interest to note the arithmetical values of the more
important terms in the new tables and the corresponding
values found by Cow-ell from an analysis of the Greenwich
observations : the latter is denoted by C. For the Evec-
tion thev use 4586"-32. C. 4586"-4; variation 2369"-95.
C. 2370"-2; Principal Elliptic Term 22639"-75. C. 22639"-.S;
.Annual Equation —658"- 92, C. —668"- 2: Parallactic inetjuality
— 125"-1(). C. — 124"-9. For a geometrical explanation of
these terms the reader is referred to Proctor's " Moon." or to
" Knowledge " for March. 1903. For the mean parallax
they use 3422" -70, agreeing well with Newcomb's gravitational
value 3422" -68 ; H.ansen's value was 3422" -24 : for the mean
semi-diameter they use 933"- 60. which is half a second less than
Hansen, and exactly agrees with Cowell's value deduced from
fifty years of Greenwich observations; Hansen's value is
evidently too great : even the new one is one second greater
than the value obtained from occultations, the difference
being due to irradiation, which causes all bright bodies to be
measured a little too large. On the whole the new tables are
a great improvement on Hansen's, and the only doubt about
their utility is due to the fact that Brown's tables are nearly
ready, and will probably be still more e.xact than these. How-
ever, there are some advantages in having two reliable tables ;
.sometimes small errors are picked up by comparing them ;
thus a small error in Newcomb's Mars tables was found by
comparison with Leverrier's tables, which are still used by the
Connaissance des Temps; I presume that it will use the new
lunar tables, starting « ith the year 1914.

ERRATA IN LAST MONTH'S NOTES.— Two points in
last month's notes need correction. The diagram showing the
change of period of Encke's comet was printed upside down.
It is now repeated correctly. Secondly, in the list of dates
of observations of the satellites of Mars, one accidentally
dropped out. The list is therefore repeated ; the dates for

+ ll"-5cos [l°-37 (t-
+ 3"-3 cos [5°-6 (t-

-1790-5)1. Period 263 years.
-1856-51]. Period 64 • 3 years.

1.

^

-^

s

i

^^

s

s

N

Iv

34

N

s.

.2 8(1

\

s

\

"^^

V

\

V

\

o .,„

I

•/■ IS

>

■6 Hi

V

.5 H

*^

v

~ l:i

\

3 HI

V

^ S

>

c

k,

.t

4

1

s

h>

y^

2

2irou

L

They make an interesting suggestion as to the
possible origin of these terms: "Consider a swarm

FiGUKH 1. l-^ncke's Comet.

438

kxowli:dge.

Novr.MISER, 1911.

Deimos are 1877-7, 1879-9, 1886-2. 1892-6. 1894-8. 1896-9.
1907-5. For Phobos 1877-7, 1879-9, 1892-6, 1894-7, 1894-8.
1896-9. 1907-5.

BOTANY.

By Professor F. Cavers, D.Sc. F.L.S.

PAPERS OX ECOLOGY.— Two of the Continental
botanists contributed papers, both on Ecology. Prof. Schroter
described in an interesting fashion " The Swiss National Park
and its Flora," giving an account of the admirable and
extensive operations of local Committees, assisted by the
Federal Government, in the useful worU of conserving the
natural features of various parts of Switzerland and protecting
the native flora from extinction. Prof. Massart described,
under the title " Phytogeography as an Experimental Science,"
various methods and results of experiments in which plants
were grown under conditions strikingly different from their
natural habitats.

Professor Cowles described his observations on advancing
sand-dunes in Michigan, which he has studied for about fifteen
years. The dunes are of gigantic size, the advancing front
having an altitude of twenty-five to sixty-five metres abo\e the
country in the path of advance. So high are the dunes and
so great their rapidity of movement, that very few of the
overtaken plants are able to survive. Curiously, the plants
able to endure partial burial by these dunes are not xerophytes.
like the pines and oaks, but swamp plants and mesophytes.
such as species of Sirlix (Willowt, Popiihis (Poplar), and
Coniiis : the shrubby plants are stimulated by the advance
of the sand to extraordinary elongation of their stems.
Survival depends upon the capacity of a plant to put forth
new roots and to elongate as rapidly as the dune advances.
In some places there are Elms thirty metres in height, above
the original countr\- level, with the tree tops projecting only
one or two metres above the sand, yet their foliage is healthy
and they flower and fruit vigorously.

Miss Sarah Baker, dealing with '" The Brown Seaweeds of a
Salt Marsh," stated that the capability of giving rise to marsh
forms seems to be shared by all the brown seaweeds inhabit-
ing the upper parts of rocky shores. Pclvctia canalicnlata,
Fiicus spiralis. Ascophyllnin nodosunu and Fiiciis
vcsicitlosiis. all show marsh varieties or species. The reason
that FitcHs serratns and F. ccmnoides have no representa-
tives in the marsh habitat is probably their intolerance of
desiccation. The physical and chemical environment factors
on the marsh being much more complex and varied than on a
rocky shore, one would expect a corresponding variation in
the structure of its plants. The most marked characteristics
of the common marsh species are a great tendency to spiral
twisting or curling of the thallus— and vegetative reproduction.
That this latter feature is not directly caused by the marsh
habitat is show^i by exceptional species where reproduction is
normal. The zoning between the brown seaweeds of a marsh
is often very striking ; but the factors governing it must be far
more complicated than those operating on the seashore.
The extensive mattings of brown seaweeds often found on
English marshes have a decidedly beneficial effect on the
Phanerogams. It seems possible that F. vuliibilis may act
as a pioneer in the establishment of salt marshes in certain
cases.

Mr. W. B. Crump contributed two interesting and detailed
papers on " The Water Content of Acidic Peats " and " The
Wilting of Moorland Plants." These two papers, somewhat
too lengthy to be reproduced here, and too condensed to be
readily summarised, represent an earnest attempt to fill a
decided gap in ecological literature and to supply exact data,
based on quantitative experimental work, regarding the water-
content, humus content, and mineral content of the soil on
moorlands, and the percentages of available soil-water for
different plants. Much work of a similar kind has been done
with arable soils, but it is important to have as much know-
ledge as possible concerning the physical and chemical

characters of economically barren soils, in order to be able to
deal better with the problems of plant distribution.

Miss Lilian Baker and Mr. B. W. Baker, contributed a paper
entitled "Types of Vegetation in the District around Maccles-
field." The area under study comprises parts of Cheshire and
Staffordshire, the four corners being roughly represented by
the towns of Northwich. Crewe, Leek, and Macclesfield. It
includes part of 111 the Cheshire Plain, largely cultivated, with
numerous parks and wooded estates, and a few sandy heaths
and "mosses": and 121 the Pennine Foothills consisting of
approximately parallel ridges intersected by the Dane valley
and other wooded ravines and covered by moors. The rain-
fall increases from the level western parts towards the hilly
east The two regions show marked geological differences ;
the plain consists of triassic rocks buried in Pleistocene times
under a thick covering of glacial deposits, while the hill region
consists of carboniferous rocks. Peat-mosses occur on the
plain in the position of former glacial lakes, but have been
largely reclaimed. The chief Associations described are (II
Moorland and Heath ; (2) Grassland, represented by heath
pastures; (3! Woodland; (4) Aquatic, and (51 Pasturage.

Prof. Oliver gave an account of " The Life History of a
Pebble Beach," and Prof. Vapp discussed " The Causes of the
Formation of Hairs and Palisade Cells in certain Plants,"
but no printed resume is available in either case ; probably
the results will be published in botanical periodicals sooner or
later, when they will be noted here. The same remark applies
to a paper read by Dr. F. J . Lewis on " The Forest Stages
represented in the Peat underlying the Moorlands of Great
Britain."

Some interesting points were raised by Mr. C. Reid, in his
paper on " The Relation of the Present Plant Population of the
British Isles to the Glacial Period." A century ago it was
generally supposed that species had originated mainly in the
districts in which they were then found ; but this presented the
obvious difficulty that the same species was not likely to have
originated at several different points, hence the anomalies of
discontinuous distribution were left unexplained, and with the
growth of the idea of evolution it was realised that faunas
and floras had a past history, even if the included species had
remained unchanged, and botanists realised that there were
many further points requiring explanation. For instance, it
was early noticed that each of our mountain tops possessed a
small outlying fragment of the arctic flora ; how, then, came
it that the same species occupied so many difterent mountains?
About sixty years ago, Edward Forbes seized the clue afforded
by the discovery of the Glacial Period, and explained the
arctic plants stranded on our mountain tops as relics of this
Period — they were left behind when the climate became too
warm for them to survive longer on the plains, and the
subsequent discovery of fossil remains of these plants scattered
over the plains, often associated with relics of arctic animals
now extinct in Britain, seemed a brilliant proof of Forbes'
view, which has been generally adopted.

But Forbes' hypothesis, granting that it explains our alpine
flora, makes more difficult, rather than easier, the explanation
of our southern flora, which occurs in a similar way. stranded
in some of the warmest low-lying parts of Britain. This
difficulty appears to have been generally overlooked. We
must start with the assumption that we have merely to account
for the incoming of our existing flora, after an eai'lier (Pre-
glaciall assemblage had been swept away as completely and
effectually as the celebrated volcanic eruption wiped out the
plants of Krakatoa. None of our flowering plants, excepting
a few arctic and alpine species, could possibly have survived
and lived through the cold of the Glacial Period. We know-
that the same temperate species that live in Britain now were
here in pre- Glacial times, hence they must have found a
refuge somewhere, but this refuge cannot have been in Britain.
During the greatest intensity of the cold all Scotland, Ireland,
and the greater part of England were buried under ice and
snow, except possibly for some high peaks on which a few-
arctic species survived; ice filled the North Sea and covered
the lowlands of England down to the mouth of the Thames,
its southern limit extending to South Wales, where tongues of

November. 1911.

KNOWLEDGE.

439

ice reached the Bristol Channel, in big glaciers like those of
the Antarctic or Greenland. The glaciation in Ireland was
even more extreme, for no part escaped — even the warmest
parts of the south-west are striated and covered by moraine
material, the ice forming bergs so large that they floated to the
Scilly Isles before melting. Obviously, no temperate plant
could survive such conditions, and even if we consider the
non -glaciated area south of the Severn and Thames, we find
evidence of such cold as precludes the possibility of warm
nooks in which the temperate flora may have survived.

If the southern plants were completely swept away by the
cold, how did they come back again, especially to islands like
Ireland and the Scilly Isles, and how did they obtain their
present singular distribution ? Before we adopt the view that
for plants to spread to islands one must have land connection
— Britain has often been connected with the Continent — one
must remember the rapidity with which the exterminated flora
of Krakatoa came back. Moreover, some peculiarities in our
flora cannot be explained by land connection ; for instance,
the Pyrenean element in our flora is practically confined to
Cornwall and the West of Ireland, but geologists nowadays
will not agree to the reconstruction of a lost Atlantis to
account for this pecuhar distribution, since no likely elevation
of the land would suffice to connect the areas mentioned.

Chance introductions of seeds during thousands of years
explain the existing peculiarities of geographical distribution
in a way that no changes of sea or land or climate will do.
Our alpine flora consists largely of survivors from a colder
period ; but the rest of our flora is constantly being added to
by chance introductions from the nearest continental shore —
hence the .Atlantic element and the Eastern element, though
not consisting to any great extent of maritime plants, are con-
fined mainly in Britain to areas within a few miles of the
coast. Seeds are evidently brought from the Continent and
scattered broadcast over certain coastal districts, and they
grow and spread where soil and climate are suitable ; but the
post-Glacial period has been so short that the process is still
incomplete, and the slow spreading inland has only as yet
extended a few miles.

-Mr. Keid concluded by stating his view that there is no such
thing as a native plant in Britain. Our flora has been swept
away like that of Krakatoa, but we have arrived at a nnich
later stage in the re-peopling of our islands. ''It seems to me
far more interesting to watch this process of introduction,
change and spreading, than to enter into speculations as to
what species shall be listed as 'natives,' 'denizens,' or
'colonists.' No such differences exist ; it is all a question of
degree. Britain for several thousand years has been receiving
colonists from all sources, and the process still goes on. The
oldest element in our flora — the alpine — occurs on nearly all
our mountains ; for it once occupied the intervening areas,
and it does not greatly depend on conditions of soil. The
limestone, aquatic, and Lusitanian flora, on the other hand,
are more recent introductions ; they can never have occupied
continuous areas, and their present distribution is full of
singular anomalies. These three elements of our flora are
steadily growing in importance, while the alpine element is
stationary or tends to die out."

PAPERS ON PALAEOBOTANV.— Palaeobotany was
well to the fore, figuring largely not only in the Presidential
.Address to the Section but also in the papers read.

In a paper entitled " A Palaeozoic Fern and its Relation-
ships " (not actually read, owing to lack of time), Dr. D. H.
Scott described a specimen of one of the simpler Palaeozoic
Ferns (Primofilices of Arber, Coenopterideae of Seward),
probably a new species of Zygoptcris [Z. Sutcliffii). The
stem of this new specimen has a five-rayed star-shaped stele,
leaf-trace bundles with axillary shoots, scale-leaves (aphlebiael,
and adventitious roots ; the characteristic internal xylem,
consisting of narrow tracheids embedded in parenchyma, is
especially well shown both in the main stem and in the
axillary stele. The leaf-trace is crescentic in section ; the
evidence of the new specimen favours the view that the large
strand given oft' from the stele is really a leaf-trace .and not

itself a branch — the branch which the leaf-trace gives off
higher up may therefore retain the name "axillary shoot"
originally given it by Stenzel ; the course of the aphlebia-
strands, given off by the leaf-traces both before and after their
separation from the stele, could be clearlv followed.

Dr. Benson described " The Structure of a New Type of
Synangium from the Calciferous Sandstor.e Beds of Pettycur,
Fife, and its Bearing on the Origin of the Seed." This
synangium, or chambered spore-case, is attributed to the
Pteridosperm Hcterangiiim gricvii, and probably represents
the pollen synangium of that plant. It differs from all
hitherto described synangia in the variety and large proportion
of its sterile tissue, which shows the sclerotic plates
characteristic of the inner cortex of Heferaiigiitin grievii.

Numerous vascular bundles with hydathodal (water-gland-
like) ends occur, and irregular longitudinal dehiscence was
brought about by the swelling of hygroscopic fibres. Another
wholly new feature is the occurrence of both central and
peripheral loculi (four central and twelve peripheral). The
loculi agree in size and form with those of the incrustation
fossil, Diplotheca stcUata (Kidston), which is identified as
the same synangium in a dehisced phase. The discovery of
the structure of this early synangium adds fresh confirmation
to the synangial theory of the seed, which may be restated as
follows : The Palaeozoic ovule of the Lagenostoma type may
be regarded as the product of the elaboration of a synangium
comparable to the above — the megaspore or embryo sac being
derived from the central group of loculi, and the canopy and
peripheral part of the ovule from the peripheral part of the
synangium with its envelope, twelve loculi, cortical tissue, and
vascular bundles.

Professor Seward read a preliminary account of his observa-
tions on a petrified Jurassic plant from Scotland, resembling
Bcniicttitcs in some respects, but showing peculiar characters
of its own, such as the presence of large quantities of fila-
mentous hairs forming a packing between the bracts of the
cone.

Mr. H. H. Thomas described some " Recent Researches of
the Jurassic Plants of Yorkshire," from which it appears
probable that some extremely interesting results may be
expected. The paper gives a summary of some results already
obtained by Nathorst, Halle and the writer. For instance,
from material collected on the Yorkshire coast, Nathorst has
recently discovered the male sporophylls of Willianisonia.
which are joined into a cup-like structure somewhat comparable
to a flower, and are covered with large sessile synangia from
which the remains of the microspores (pollen-grainsi can be
extracted by treatment with acid ; the female cone of
Willianisonia closely resembles that in Bcniicttitcs. but
the flowers were unisexual. Thomas recently found a new
Bennettitalian flower which appears to be bisexual, like the
American specimens of Bciincttitcs (Cycadcoidca) ; the
central axis bore the usual ovules and intraseminal scales, and
below this there was a whorl of five or six large free sporophylls
arranged like the petals of a hypogynous flower, each bearing
five or six large kidney-shaped sporangia. Reference was
also made to the discovery of small fruit-like bodies named by
Mr. Thomas as Cay ton ia ; they appear to contain the remains
of about ten seeds, and similar isolated seeds have been found,
some of the structure being preserved — e.g., integuments,
micropylar tubes, and nucellus. Among various interesting
Ferns there are forms allied to such modern genera as Todca.
Cyathea, and Marsilia.

In a short paper. Miss Lockhart made a "Contribution to
the Theory of the Formation of Calcareous Nodules containing
Plant Remains." Three boulders from the Calciferous Sand-
stone of Pettycur were entirely cut into thin serial sections in
the search for a minute object, and it was thus possible to
trace the position, in a block, of any particular plant.
Metaclcpsydropsis duplex and Botryopteris antiqna were
chosen, as they presented a contrast between a large and a
small plant. The clear delimitation of even the smallest frag-
ments points to mechanical fracture subsequent to inunersion,
and the parallel position of plant remains in the boulder further
indicates the agency of water currents. The results confirm

440

KNOWLEDGE.

November, 1911.

the actual site of

Dr. Gordon's views of thermal pool;
petrifaction.

PAPERS OX FLXGI AND BACTERIA.— Mr. A. S.
Home described the nuclear divisions which occur in a Fungus
parasitic on the Potato, Spoiigospora sulani, a member of
the lowly group Plasmodiophoraceae. Several other genera
of this group were also dealt with by Mr. T. G. B. Osborn in
a paper entitled, " The Life Cycle and Affinities of the
Plasmodiophoraceae." Without entering into the technical
details of nuclear division described in these papers, it may
be stated that the observations made tend to strengthen the
suggested relationship of this group to the Slime-Fungi
(My.xomycetesl and possibly also with the Chytridiaceae. In
Spoiigospora solan i. Home describes a very curious form of
nuclear division, in which four loop-like chromosomes appears
and later join end to end to form an equatorial ring around
the nucleolus ; this ring divides into two daughter rings, each
of which finally breaks up again into four chromosomes, while
the nucleolus constricts to form two daughter nucleoli.

Professor Bottomley described the structure and function
of the root-nodules of the bog myrtle (Myrica gale) which
are formed as modifications of normal lateral roots, these
branching and forming clusters covered with rootlets growing
out through the end of each nodule or branch — the branching
is due to the outgrowth of lateral roots, and not to forking
of the apex of the primary nodule, as in the nodules of Cycas,
Alder and Elacagnus. The cortex of a young nodule contains
(a) numerous cells with bacteria, and (6) cells filled with oil
drops : towards the apex of the nodule the infection threads can
be seen passing from cell to cell, and the whole nodule is covered
by two or three layers of cork cells. Pure cultures of the
bacteria show small rod-like bodies resembling Pseudoiuonas
radicicola. the organism found in all Leguminous nodules,
and giving a definite fixation of nitrogen when grown in flasks.
Voung Myrica plants grown in pots in soil deficient in nitrogen
flourished well if possessing nodules ; if without nodules on
their roots they soon died. I-'xidently the nodules of Myrica
are concerned with the assimilation of atmospheric nitrogen,
as are the root-nodules of Cycas. Alder, Elacagniis and
Podocarpns, the other known genera of plants outside of the
Leguminosae which have root-nodules.

PAPERS ON PHYSIOLOGY. — Professor Bottomley
described " Some Effects of Bacteriotoxius on the Germination
and Growth of Plants," illustrated by some remarkable photo-
graphs of comparative cultures. An aqueous extract of well
rotted manure or fertile soil, obtained by treating one hundred
grammes of manure or soil with five hundred cubic
centimetres of isotonic salt solution and filtering through
a Pukall filter, has an injurious effect on the germina-
tion of seeds and their further growth in sand, even
when supplied with normal food solution. This inhibitory
effect of the extract can be destroyed by boiling. The harm-
ful effect is due to the presence of certain bacteriotoxius,
probably of the nature of toxalbumoses, formed by the activities
of the decomposition and denitrifying bacteria in the manure
or the soil, and by heating the toxic influence is destroyed and
the substance rendered available as a nutrient.

Experiments with germinating seeds of mustard, turnip,
tares, and barley gi\e support to this theory. Seeds
germinated in pots containing sand moistened with (rt)
distilled water, (h) saline solution, (c) raw extract, Irf) boiled
extract, showed that the raw extract almost prevented
germination and the subsequent growth was very feeble,
whilst the boiled extract, although slightly retarding
germination at first, soon appeared to benefit the seedlings
which became stronger and healthier than those grown with-
out extract. The extract was also found to have a marked
influence on the growth of certain soil organisms. It
stimulated the growth of denitrifying bacteria, and inhibited
the growth of the nitrogen-fixing bacteria. Both these eftccts
were destroyed by boiling the extract.

Mr. S. Mangham, who has already done useful and interest-
ing work on the translocation of carbohydrates in plants,
described some of his observations on the presence of sugar

in the tissues of the Sea Tangle, Lain in aria. The two
species L. digitata and L. saccharina were examined for
sugars at various times of year by means of Senft's method of
forming osazones. Observations were made upon sections
cut from the stipe, the region of new growth, and from the
lamina. Crystalline osazones have been found in the cortical
cells, the sieve-tubes, and the hyphae in both species, and
particularly at the time of formation of the new lamina in
L. digitata. Some of the crystals in the latter plant very
closely resemble those yielded by maltose, but their exact
identity is at present unknown. This production of osazones
in the hyphae and in the sieve-tubes after treatment with
Senft's reagent aflVirds experimental evidence in support of the
conducting and storing function hitherto assigned to these
elements mainly on account of their structure.

Miss Eraser described in detail " The Longitudinal Fission
of the Meiotic Chromosomes in Vicia Paha."

Dr. A. .A.. Lawson, in a paper on " Nuclear Osmosis as a
Factor in Mitosis," put forward views which run counter to
some generally accepted interpretations of the phenomena of
nuclear division, and which are likely to lead to further
discussion. Dr. Lawson claims to have discovered that the
nuclear membrane does not break down or collapse at anv
period, but behaves as one would expect a permeable plasmatic
membrane to behave under varying osmotic conditions ; and that
the achromatic spindle can no longer be regarded as an active
factor in mitosis, but is simply the passive eflect or expression
of a state of tension set up in the cytoplasm and caused in the
first place by nuclear osmotic changes.

Miss L. Digby gave a preliminary account of the cytology
of the hybrid Primula Icewcnsis, its parents, and the ensuing
generation. The original P. kezcensis appeared in a pure batch
of P. floribunda seedlings at Kew in 1899, and proved to be
a cross between P. floribunda and P. vcrticillata. The
hybrid was sterile, with only thrum-eyed flowers, but some
years later a single pin-eyed flower was noticed in Veitch's
nurseries. This was promptly fertilised, good seed was set,
and the resulting plants had both pin-eyed and thrum-eyed
flowers and were fertile. Thus the whole fertile or seedling
stock of P. heu'cnsis owes its origin to the one pin-eyed flower
on the sterile or type stock of P. keiccnsis.

The parents of P. keiccnsis (sterile) have identically the
same number of chromosomes, and (as might be expected) this
number is repeated in the hybrid : P. floribunda, P. verti-
cillafa. and P. keiccnsis (sterile) all have eighteen (2x) and
nine (x) chromosomes. The surprising phenomenon occurs
in the seedling P. keiccnsis, in which there are thirty-six (2x)
and eighteen (xl chromosomes. By some means either at, or
subsequent to, the fertilisation of the pin-eyed flower on the
sterile stock the number of chromosomes has been duplicated :
this doubled number is continued throughout the generations
of the fertile P. keiccnsis, and is also characteristic of the
variety P. kewensis farinosa. This increase cannot be
accounted for by apogamy ; the divisions in the embryo sac
mother nuclei of both sterile and fertile forms are normal,
and in the one case nine (x) and in the other eighteen (x) chro-
mosomes are seen at meiosis, while in the surrounding tissue
there are correspondingly eighteen (2x) and thirty-six (2x)
chromosomes. The doubled number of chromosomes has
since re-appeared in a cross made in 1910, at Kew between
P. floribunda var. isabcllina and P. vcrticillata ; the
resulting hybrids not only resemble P. kewensis farinosa in
external features, but also possess thirty-six (2x) chromosomes.

This remarkable sudden duplication of chromosomes has
its counterpart in the Oenotheras. Oc. Laniarckiana has
fourteen (2x) and seven (x), while Oc. gigas which mutated
from Oc. Laniarckiana has twenty-eight and fourteen. Like
the fertile P. keiccnsis, Oc. gigas has again arisen from two
sources — once as a hybrid and once from a pure strain of
Oc. sublinervis. In the Oenotheras, as there is no evidence
of the addition of new unit characters, the doubling of the
chromosomes is believed to be brought about by longitudinal
fission. In the Primulas the phenomenon is apparently
associated with the change from the sterile to the fertile
condition.

XOVEMliER, 1911.

KNOWLEDGE.

441

When P. tlorihiiiula var. isabcUina. with its eighteen and
nine c.hroniusomes. is crossed with /-". kcicensis seedHng form,
with its thirty-six and eighteen, the offspring resemble the seed-
parent (P. floribitnda var. isabcUina) both in external
characters and in number of chromosomes. By some
regulating process the sum of 9 (xl + lS (x) = 18 (2x1. Again
an analog)' is found in the Oenotheras, for Oe. lata (fourteen
and seven chromosomes), crossed with Oe.gigas (twenty-eight
and fourteen chromosomes), results in a hybrid with_ twenty-
one (2x1 chromosomes; according to Geerts, at meiosis the
seven homologous chromosomes derived from either parent
become paired, while the seven supernumerary unpaired
chromosomes disintegrate, and in this way the x number of
chromosomes in the hybrid is reduced to that of the parent
w'hich possesses the lowest number.

MISCELLANEOUS I^'^PERS.— Miss Kershaw described
the ovule of Boiccnia spcctabilis, which agrees on the whole
with other genera of Cycads. The pollen chamber of
Boux'nia forms by the breaking down of a strand of
elongated cells, extending from the tip of the nucellus aliuost
to the megaspore. First a small cavity (upper chamber)
forms in the narrow apex of the nucellus, and this probably
accommodates the pollen when it enters the ovule. The
nucellar tissue below gradually breaks down, forming a larger
ca\ity (lower chamberl, into which the pollen grains pass from
the upper chamber. The upper and lower chambers
correspond in function with the lagenostome and plinth of
such fossil seeds as Coiinstoma, but are much less specialised
than the corresponding structures in the Lagenostomales.

Mr. Home discussed " The Polyphyletic Origin of Cor-
naceae," giving the results of detailed study of the flower of
several genera of this order, together with comparative studv
of the effects brought about by progressive sterilisation and
reduction in the ovary of the Caprifoliaceae, Hamamelidaceae,
and Araliaceae. In the Caprifoliaceae every intermediate
stage may be found between ovaries of the Lcycesteria type
(double rows of ovules in each chamber) and uniovular ovaries
[Vibnniinn) ; progressive reduction trends to the uniovular
condition, but each genus pursues an independent course of
development towards this condition. In the Cornaceae. the
flowers possess certain resemblances, e.g., polypetaly and
epigyny, while the ovaries or loculi in some genera are
uniovular with terminal ovules, but they possess peculiarities
in (a) structure of ovarj' (Corniis) ; (6) vascular supplv of
ovary {Garrya) ; (c) vascular supply to ovule [Grisclinia) ;
((f) form of ovule (Davidia) ; (c) structure of nucellus
{.Aitcuba^ ; and so on. It is suggested that these peculiarities
indicate different origins ; the general resemblances in
structure do not appear to be of any considerable value in
establishing close relationships in the order, but are to be
regarded as striking parallelisms brought about by the opera-
tion of similar evolutionary processes upon distantly related
forms.

During the Portsmouth meeting, a semi-popular lecture was
delivered by Dr. F. Darwin on " The Balance Sheet of a
Plant ■" ; while one of the evening discourses was given by
Professor Seward, his subject being '" Links with the Past in
the Plant World."

Two interesting Excursions were made by the Botany
Section, one to the New Forest to study especially the heath
vegetation, the other in a steam launch up Southampton
Water for the estuarine vegetation, and especially the Spartina
grasses.

CHEMISTRY.

By C. AiNswoRTH Mitchell, B.A. (Oxox.), F.I.C.

NATURAL GAS IN GALICIA.— Dr. K. Feldmann,
writing in Petroleum (1911. VI. 2232), gives an interesting
account of the steps recently taken to utilise the natural gas
emitted from the borings for petroleum oil in the Bor\'slaw-
Tustanowice oil-fields. Until about two years ago this gas
was. for the most part, allowed to escape into the air, only a
small proportion being used for heating and power purposes
upon the spot. Recently, however, a pipe-line has been

constructed for conveying the S'lperfluous gas to Drohobyc^,
a distance of o\er eight kilometres, where it is intended to
utilise it in the oil-refineries and for distribution in the town.

The gas issuing from the borings is colourless, and has a
specific gravity of about 0-75 and an average heating capacity
of about 10.S35 calories per cubic metre. Two typical
samples from different borings contairu'd S-7 and S-8 per
cent, of heavy hydrocarbons ; 86- 5 and Sj ■ 1 per cent, of light
hydrocarbons : 1-0 and 1 ■ 7 per cent, of oxygen ; and 3 • 8 and
6-4 per cent, of nitrogen (corresponding to 5 and 8 percent, of
air) respectively.

The various pipes conducting the gas from the different
borings come together at Kamilla. and it is intended to establish
a central power station at that point. Here the gas is freed from
moistm-e. and passes through an apparatus which records the
percentage of air, this precaution being taken to prevent an
explosive mixture (one containing over 10 per cent, of air)
being distributed. As the gas is poisonous a small addition of
mercaptan is also made at this stage, in order to render any
escape perceptible by its odour.

The main pipe is constructed of steel tubes which have been
tested in the works up to a pressure of ten atmospheres, and
these are coated with a layer of jute surrounded within the
trench with tar and lead. The finished pipe line is tested up
to a pressure of four atmospheres, although the maximum
pressure at which the gas is driven through it does not exceed
1 • 8 atmospheres.

BOLOGNA LUMINOUS STONES.— Lemery in his
"Treatise of Chymistry." published in 1720, in a section
upon the Boionian Stone, describes it as " a small gray stone,
weighty but soft, sulphureous, sparkling in many Places, of
the Largeness of a Walnut, whose Surface is not equal but
bunchy and protuberant and the opposite side is hollow.
Large Stones are only \aluable for their Rariety : for they are
not so good to make the Phosphorus, because commonly they
are opaceous ; the small ones are nmch better, they shine
more and ha\'e fewer Blemishes." According to Lemery the
nature of the phosphorescence was investigated by an Italian
who '■ did particularly apply himself to this Discovery, and he
made great Progress in it. But it does not appear that he did
communicate the same to any Body, so that the secret has
been buried with himself many years ago."

Since the days of Lemery the phosphorescent stones of
Bologna have frequently been examined and it has been
shown that the luminous property depends upon the presence
of sulphides.

In a recent issue of the Jouru. prakt. Cheiu. (1911.
LXXXIV. 305) an account is given of experiments made by
Messrs. V'anino and Zunibusch to ascertain the factors upon
which the luminosity depended. They found that good
specimens of the stones contained from twelve to thirty-three
per cent, of sulphur, and that the condition in which that
element was present had a pronounced effect upon the results.

Thus stones containing only monosulphides were very
deficient in luminosity, whereas in highly phosphorescent
specimens there was a considerable amount of polysulphides
(up to 2-5 per cent.) A small addition of starch increased
the luminosity, but a larger proportion than about four per
cent, had the opposite effect. The length of exposure to day-
light required to induce the maximum phosphorescence varied
with the composition of the stone, those of more complex
character requiring a longer exposure, though they also
showed a correspondingly longer period of decay.

The luminosity was not increased by confining the stone
in an atmosphere of chlorine or ammonia. It was reduced to
a marked extent by grinding the stone in a mortar, the colour
being simultaneously altered. Exposure to sunlight also
changed the colour, but it was not possible to trace any
connection between the luminosity of the stone and the speed
with which its colour altered.

CHEMISTRY AT THE BRITISH ASSOCIATION.—
The address of the President of the section. Dr. Walker,
deals with the "Theories of Solutions." which have arises
upon the foundations laid by van t'Hoft'. A masterly outline in

442

KNOWLEDGE.

Xovemb?:r, 1911.

ijiven of tlie present ideas upon the subject, and it is sliown
how certain conflicting notions may be reconciled.

Other important contributions are devoted to the
■' Absorption Spectra of Metallic Vapours." by Dr. Be\an.
""The Compressibility of Mercury," by Dr. McLewis; and
""The Use of Indicators for determining .Affinity Values," by
Dr. \'. H. \'eley. There is also an interesting paper on "The
Theory of Colloids," by Professor Freundlcr. in which lie
classifies colloidal (or glue-like) solutions into two groups. \i/..
those in which the solid body, e.g.. a colloidal metal, is in a
state of extremely fine suspension, termed " Suspension
Colloids " or "" Lyophobic Sols " ; and " Kmulsion Colloids "
or ■■ Lyophilic Sols " (including gelatin solutions and the like)
which approximate more closely to true solutions.

In a paper upon "' The Treatment of Wheaten Flour." Mr.
.A. Humphries describes the results of his investigation of the
changes produced in flour on baking. From these it appears
that a large proportion of the organic phosphorus present is
converted into an inorganic form.

ALUMINIUM NITRIDE AND ITS USES. — On
heating aluminium powder in the air it absorbs oxygen and
nitrogen in proportions depending upon the temperature
reached. Thus, at 600' C. oxygen is absorbed up to 8-S per
cent, of the weight of aluminium, but there is little or no
absorption of nitrogen ; while at SOO'C. the amount of nitrogen
absorbed is trifling. On raising the temperature to llOO'C,
rapid absorption of both oxygen and nitrogen takes place, until,
after about six hours, the metallic aluminium has been con-
verted into oxides and nitride, the absorbed nitrogen being
subset|uently displaced by oxygen, with the final production of
a hard aluminium oxide resembling alumina in properties but
containing a different proportion of oxygen.

When the aluminium is heated in an atmosphere of
nitrogen at 900°C., it absorbs 12-21 of that element, to form
a nitride, which is decomposed into an alnminimum oxide
when heated in the air at temperatures abo\ e ,sn()°C.

In the current issue of the Bull. .Assoc. Chiiii. Siicr. ct Dtst.
11911, X.XVIII, 10101, M. Kohn-Abrest recapitulates his work
on this subject, outlined above, and suggests that it may be
possible to prepare aluminium nitride on a large scale from
bauxite, or alumina, in the electric furnace. The products
would contain from ii to 34 per cent, of nitrogen, and in the
case of bauxite would cost less to make than sodium nitrate,
containing' 15-5 per cent, of nitrogen. Further experiments
are needed, however, to ascertain whether ammonia could be
produced economically on a large scale from this source : or
whether, if applied to the soil as a fertilising agent, aluminiimi
nitride, as thus prepared, would part with its nitrogen in the
form of ammonia.

GEOLOGY.

By G. W. Tyrrell, A.K.C.Sc, F.G.S.

(JU.ART/ \'i:iNS. — Whilst in manv cases undoubtedly
due to deposition from water containing silica in solution, it is
now thought that some quarts veins may ha\'e an igneous
origin. The " aqueous " veins generally have a " comb " or
other regular structure growing out from the sides of the
fissure in which they have been deposited. Quartz veins of
igneous origin have a coarse pegmatoid structure, and may
show graduations in mineralogical composition uniting them
with typical pegmatites. The latter are admittedly igneous,
and represent the final product of the slow crystallization of
the more volatile residual portions of a granitic or syenitic
magma. These mother-liquors, rich in magmatic water, were
forced into fissures of the already-solid magma, or into the
adjacent country-rock, where their extreme liquidity permitted
the formation of very large and perfect crystals of the later-
crystallized constituents of the magma, such as quartz and
orthoclase. (Juartz veins associated with granite masses may
be regarded as pegmatites eompo.sed entirely of quartz, and
there is no reason why they should not have the same origin
as the more normal pegmatites.

It is to be remarked that the distinction between '" aqueous "
and " igneous " becomes very shadowy in the case of quartz
veins. In discussing pegmatite Mr. Harker remarks: "The
magma or solution, from which the pegmatites crystallised
was igneous, in that it was the residual part of a granitic or
syenitic or other igneous magma, of which the greater part
had already crystallised under plutonic conditions. It was
.aqueous, inasmuch as it contained, perhaps very richly,
magmatic water, concentrated (with other volatile constituents)
in the residual magma by continued crystallization of
anhydrous minerals. The pegmatites themselves represent
this watery residual magma, except that the greater part of
the water and other volatile substances was expelled in the
final crystallization .... Logicallv, indeed, we might
include under the same head simple quartz veins crystallised
from solution in water (at perhaps 200'-'C), if both quartz and
water were of direct intratelluric origin, the final residuum of
an igneous rock-magma."

Some observations bearing on the origin of quartz veins
in association with a granite mass have "oeen made by
^\^ C. Simmons, in a paper on the Foxdale Granite of
the Isle of Man [Gcol. Mag., August, 1911). In both the
larger granite mass at Foxdale, and the smaller one of Eairy,
thick \eins of quartz and co.arse pegmatite occur. Sometimes
these quartz veins, then resembling dykes, are found, outside
the granite, intruded into the country rock. .Associated with
them and with the granite are characteristic dykes of micro-
granite intruded into the slates with a N.W. — S.E. trend.
The veins occur in greatest number on the south-side of the
intrusion, and attain a maxinunn thickness of eighteen feet.
In the large Foxdale Silica Ouarry several veins are to be
seen, which pass locally into a quartz-mica pegmatite. In
one case a vein has a selvage, half-an-inch thick, consisting of
a felted mass of bronzy mica ; in another the selvages, again
half-an-inch thick, are composed of a mixture of quartz and
orthoclase. The evidence seems to support the theory that
the quartz veins represent the final consolidation product of
the granite magma. The seh'ages are believed to be due to
the segregation of impurities from the molten silica solution.
There is no sign of " comb " or any other structure to
indicate that the seins are due to vapour or water deposition.

PETROI.KArHlCAL I'R'JVINCES.— In hi^ I'residential
.Address to the Geological Section of the British .Association
at Portsmouth, Mr. Harker took as his subject "" Some Aspects
of Modern Petrology." Most of the address was concerned
with what one may call " regional petrology" — the space and
time distribution of igneous rocks. This is a fascinating sub-
ject, and its study is opening up some wide problems, and
gi\ing not a few hints as to that natural classification of
igneous rocks which belongs to the future, but which at present
is merely hoped for. Petrographical provinces are, in Mr.
Harker's words, " more or less clearly defined tracts, within
which the igneous rocks, belonging to a given period of
igneous activity, present a certain community of petro-
graphical characters, traceable through all their diversity, or
at least obscured only in some of the more extreme members
of the assemblage." It is natural to attribute such a family
likeness amongst a given group of igneous rocks to a
community of origin. The simplest hypothesis is that which
holds all the varied types of a petrographical province to
have been evolved by the progressive differentiation of an
originally homogeneous parent-magma. Becker holds the
view that petrographical provinces are the expression of a
primaeval heterogeneity of the earth's crust, which has
persisted throughout geological time. This is diflicult to
reconcile with the small extent and sharp definition of
provinces like that of .Assynt or the Bohemian Mittelgebirge.
An even stronger objection is that petrographical provinces
are not permanent. In the Midland \'alley of Scotland, for
instance, a calcic petrographical province (Old Red Sand-
stone) is followed by one distinctly alkaline (Carboniferous),
extending over almost exactly the same area. Daly's theory
of the origin of alkaline rocks as due to the assimilation of
limestone by calcic magmas, is open to the same serious
objections.

XOVEMBER, 1911.

KNOWLEDGE.

443

In the land areas of the globe, calcic magmas have a
decided predominance over the alkalic. Mr. Harker makes the
interesting suggestion that this is due to the association of
alkaline rocks with areas of subsidence. In connection with
this it is remarked that the volcanic islands in the Atlantic,
from the Azores to Tristan d'Acunha (and, it might be added,
many in the Pacific) have igneous rocks of alkaline facies, and
conceivably belong to very extensive tracts of alkaline
material now submerged under the ocean.

Mr. Harker is inclined to drop those unhappy terms
" Atlantic " and " Pacific," as applied to, and synonymous
with, the alkaline and calcic branches respectively of igneous
rocks. Nevertheless the distribution of types upon which
that nomenclature rests is regarded as none the less significant.
The distribution coincides not with the Atlantic and Pacific
oceans, but with the contrasted tectonic structures which
border those oceans. Consequently it is not to be expected
that the oceanic islands of the Pacific should necessarily have
igneous rocks of calcic facies : on the contrary, the dominant
element in their tectonics, according to Suess, being of
Atlantic type, the igneous rocks should be generalh' alkaline,
as in fact they are. The observed alkalinity of the igneous
rocks of Hawaii and Tahiti, therefore, instead of constituting
an objection, as urged by some American petrologists. con-
firms the simple generalization of distribution made by Harker.
Becke and Prior.

METEOROLOGY.

By John .\. Ctrtis. F.R.Met.Soc.

The weather of the week ended September 23rd. as set out
in the Weekly Weather Reports issued by the Meteorological
Office, was at first very fine and dry, though cool, but about
the middle of the week there was a change, rain fell generally
and thunderstorms occurred. The temperature was below
the average in all districts, for the first time since the end of
June. In the North the deficit was but slight, but in the
Midlands and the South it was greater, reaching 3°-0 in
England S.E. The highest maximum was 73" at Tottenham
on the ISth, the next highest being 70°. reported at both
-Aberdeen and Guernsey, on the same day. The lowest of the
minima were 24" at West Linton, 25° at Balmoral and 29" at
Marlborough It was only at a few stations, however, that the
temperature fell below the freezing point. In \\"estminster
the minimum was 41". On the grass the temperature fell to
18° at Llangammarch and to 22° at Balmoral. Hereford and
Marlborough. Rainfall was in excess in all districts excepting
Scotland, E. and W. The excess was greatest in the South-
\\'est, where at Falmouth and other stations the total fall was
more than twice as much as usual. Sunshine was in excess in
the Central and Eastern parts of the kingdom, but w-as in
defect in the western districts. The sunniest stations were
Felixstowe and Clacton with 61 hours (71%). At Westminster
the aggregate was 47-2 hours (55%). At Aberdovey the total
was only 13-9 hours (16%). The mean temperature of the
sea water ranged from 51° -4 at Wick to 62° -9 at the Shipwash
Lightship.

During the week ended September 30th the weather was
changeable and unsettled, with frequent heavy rain. Temper-
ature was below the normal in Scotland, England. N.W.. and
in Ireland, but abo\e it elsewhere. The differences, however,
were nowhere very large. The highest of the maxima ranged
from 62" at Strathpeft'er. in Scotland. E., to 72° at Geldeston.
in England, E.. and at Greenwich. The lowest of the minima
was 28" at Balmoral, on the 25th, .and only at this station did
the shade temperature fall below the freezing point. On
the grass, however, readings were in places much lower,
down to 21° at Llangammarch, 23° at Crathes, and 24° at
Balmoral. Rainfall was variable. There were some very
heavy falls in Ireland and Wales on the 25th: 3-00-ins.
at Roches Point, 2-23-ins. at Waterford, and 1-40-ins. at
Bettws-y-coed; but in the South there were stations where the
amount for the week was only 0 -3-111. or even less. Bright
sunshine was above the average in all districts, most so in

England. S.E.. where the sunniest station. Worthing, reported
57-6 hours (69%). The temperaf: ' ' :;ea water varied
from 45° at Ballantrae to 63° a: vash Lightship.

The week ended October 7th was coid and dry, with strong
winds and gales in the early part. Temperature was low
everywhere, especially so in England. S.E., where the mean
was only 48° -0, compared with the average 52° -9. The
highest reading reported was 62° at Colmoiiell; but at the
majority of stations the maximum did not reach 60°. The
lowest readings were 2^ at Balmoral. 27° at Cally (Gatehouse),
and 29° at Mai-lborough. The lowest on the grass were 17° at
Llangammarch, 19° at Hampstead, and 20° at Balmoral.
Rainfall was slightly above the average in England, S.E., and
much above in the English Channel, where at Jersey the
amount collected was just double the average. The driest
district was Scotland. W., where Glasgow and Dumfries were
rainless. At Tunbridge Wells and at Canterbury there were
falls of over an inch on the 4th.

Sunshine was about the average, except in Scotland. \\'..
and in England. N.W., where it was in excess, and in the
English Channel where it was in defect. Douglas reported
the largest aggregate 41-0 hours 151%), while Markree Castle
reported the least, namely 14-0 hours (187°). The tem-
perature of the sea water ranged from 46° at Kirkwall and
Scarborough to 60° at the Shipwash and at Salcombe. A
pilot balloon sent up at Manchester on the 3rd August
was traced to a height of 25 kilometres, or more than
15? English miles.

The week ended October 14th was fine generally, but with
a good deal of mist and fog. Thunderstorms occurred in
several places on the 13th. Temperature did not vary greatly
from the average. There was an excess in England, E., S.E.,
and S.W., the English Channel, and Ireland. N., but a
deficit elsewhere. The highest readings were 68° at Green-
wich, Prestwich, Bettws-y-coed, and CuUompton ; the lowest
were 24° at Balmoral and 26° at Kilmarnock. Except in
England, E., and the English Channel, temperatures at or
below the freezing point were experienced in all districts.
In the English Channel the minimum was 46°. On the
grass the temperature fell to 17° at Llangammarch and to
20° at Balmoral.

Rainfall was extraordinarily low, and in seven of the twelve
districts into which the country is divided for the compilation of
meteorological statistics, the mean amount of rainfall was less
than 0 • 1 inch, and in Scotland. W.. the week was rainless. .At
manj' individual stations also, in other districts, the week was
rainless. On the other hand, at Jersey, on the 13th, 2-42
inches of rain fell in one day. Bright -sunshine was above the
average except in Scotland, N.. and in Ireland. The sunniest
district was England. N.W., with a mean of 40 hours (53%) ;
the sunniest station was Llandudno, with 51 hours (67%). The
lowest record for the week was 0-6 hours at Baltasound.
Shetlands. The temperature of the seawater ranged from 44°
at Ballantrae to 59° at Salcombe.

THE SUMMER OF 1911.— In the thu-teen weeks of
summer ended September 2nd, the weather in England. S.E.,
had been imusually warm in ten weeks, unusually dry in eight
weeks and unusually bright in nine weeks. The corresponding
numbers for the summer of 1910 were respecti\ely three,
four and one.

INTERNATIONAL INVESTIGATION OF THE
UPPER AIR. — During the period. September 11th to 16th.
simultaneous ascents of unmanned balloons were made at a
large number of stations in Europe and elsewhere. The
co-operating stations in the British Isles were Pyrton Hill,
Oxon ; Ditcham Park. Petersfield ; and Manchester, in
England ; Crinan Harbour, in Scotland : and Mungret
College, Limerick, in Ireland.

Small ballooms carrying recording instruments were dis-
patched simultaneously, and the return of the records and the
tabulation of the results is anticipated with much interest.
One balloon sent up at Limerick was found at Ballater, in
Scotland.

-(4-t

KNOWLEDGE

NoVEMIiER. mil.

MICROSCOPY.

By A. W. Sheppard. I'.K.M.S..

icith the assistance of the folluicuig iiiicroscopists : —

.\rjhurC. P.anfield. Arthl'r Eari.ano. K.R.iM..S.

The Rev. E. W. Bowei.l. M.A. RrillAui) T. Lewis. F.K.M.S

Iames BtRTON. Chas V. ROISSELET, P.R. M.S

Charles H. Caffv.v D. I. ScoiRKfElli. F.Z.S., F.K.M.S.

C. D. Soar. K.L.S.. F'.R.M.S.

.\ CASE OF DI.ATOM-WELDIXC;.-
graph illustrates the probable fusion of tu
taken place during mounting.
The slide is an old one by
Wheeler, labelled " Test Slide.
Dry, Ainphipleura pcUucida.
■iV in. obj," and it is a mixed
one. Mr. West, to whom this
photograph and others taken at a
magniticatiou of X 1000 were
submitted, is of the opinion that
the smaller valve lying alongside
the .4. pclliicida is a Navicnla
laci'issiiiiiT. and that the junction
is an accidental one. I under-
stand that in mounting test
diatoms dry, it is the custom,
after cleaning the cover glass,
to place upon it a drop of the
material with a drop of added
water, and allow evaporation to
take place slowly. The cover is
then placed on a piece ot
platinum foil or ferrotype plati
which is heated to redness, and
it is doubtless at this stage of
the process that the unnatural
union has taken place.

Obj. 2 mm. H.O.I. .Apochromat
X.A. 1-40 (Leitzl, Oc. Compens.
X IS. Achromatic Substage Con-
denser. .Auxiliary Lens icifh Ins. Screci
and Wainwright. '" M " Series. Liliput

T. W. HUTC

— The photomicro-
o diatoms that has

^

\

\

; (1) + H.l Wrattcn
.Arc lamp. .S Amps.

HER. M.B., CM.

spontaneous motion. In reprnduction zoogonidia are formed
with two cilia (I-'igure 2 cl, which swim away, but their actual
de\elopment into a fresh colony has not been observed.
Sometimes when a specimen has been kept in a collecting
bottle for a few days, it will be found that all the cells have
taken this form and settled on the side of the bottle towards
the light, leaving the structureless jelly useless for exami-
nation. It is very doubtful if there is more than one
well-established species, to which, however, a considerable
amount of \ariafion, owing to environment and age. nmst
be allowed. My example, in which the cells, from eight to

ten A< diameter — are arranged
in groups of two or four, corres-
ponds best with Tctraspora
hihrica (Roth), Dr. Cooke
gives four species, but is very
doubtful about the last of them,
and c c r t a i n 1>- the fi r s t , T.
bullosa, from the figure —
'"British Freshwater .Algae"
Plate 5, Figure 1, appears to
resemble Monostroiua rather
than Tetraspora; in the latter
genus the cells should be at
least sub - spherical except
when undergoing division.
Neither does he refer to the
" pseudocilia," which, though
they are easily overlooked and
cannot be distinguished in all
cases. West makes of dia-
gnostic importance. Who also
mentions the occurrence of
hypnospores — i.e. resting spores
— with thick brown cell-walls, but
I have not seen them. Con-
siderable importance is attached
to the plant from an evolutionar>-
point of view — West's " British
Freshwater Algae," page 24.
from m\' own specimen, b and c are from
aboxe book.

J. Burton.

~IGfKE 1.

Figure 1 a is
figures in the

St o- oo (for, O *«R«

00 c,;^ ..

»" **«&> 6 00 oat* •^1^*°

TETR.ASPORA I LINK). —At a recent excursion of the
Ouekett Club I came across Tetraspora, an alga perhaps not
very frequently met with, and most likely often overlooked
when it does occur. It was clinging to some weeds in water
about a foot deep near the edge, and appeared as a pale green
filmy looking body without any
definite outline. There was
some difficulty in collecting it —
so fragile was it. that an
incautious mo\ement with the
net at once caused a part to
disperse in the water. The
plant consists in its young
condition of a colourless gela-
tinous sac, which later extends
in various directions, becoming
lobed, torn and membranous
finally, it may reach a consider-
able size, up to several inches in
length. In this are embedded
in a single layer the cells which
are the living units of the organism. Typically they are globose,
of various sizes, according to age, and when mature divide
first into two hemispheres, which soon divide again at right
angles in the same plane. The four portions, at first somewhat
angular, subsequentlv become rounded off, but not usually
separating far from each other, cause the grouping into four,
which is the noticeable characteri.stic of the plant. The
mother cell-wall swells and becomes gelatinous thus increasing
the extent of the colony (Figure 2 al. During some period at
least of their life these cells are provided with two long
" i)seudocilia " (Figure 2 b), but the organism as a whole has no

^

'■^.^ Op*«ooOcgO«/'°0<S>!»,S

e^'

^

/!/ M (1

Figure 2.

T.-VB.\NID.AF. — The cxception.illv fine and hot weather of
the past suuuner has resulted in an unusual profusion of insect
life, and in no respect has this been so apparent as in the
case of the Tabanidae, which, especially abroad, have been so
numerous as to constitute a veritable plague. Not only have

the grey Breeze Hies been
remarkably abundant, but the
larger species of Tabanus
varying in size from one-half
inch to one inch in length,
beset the traveller wherever he
went, even on the higher slopes
of the Alpine pastures, above
the tree level to a height of
o\ er nine thousand feet. F'or
the protection of the face
and neck a light veil was
effective, but the hands and
legs were especially exposed
to attack, since these flies
could alight upon a glove or
stocking without being noticed, and could easily pierce
the skin through any tight-fitting garment. As regards the
Tabanidae, the males appear to subsist on the juices or
secretions of plants, but the females are extremely blood-
thirsty, and lose no opportunity of attacking both animals and
human beings. The mouth organs of the various species are
similar, and are of considerable interest not only to the micro-
scopist, but also to many others who, whilst suffering from the
bites, at least like to know by what means they are bitten.
The large fleshy proboscis — or labiniu — common to both
male and female, does not greatly diller in shape or structure

\OVKMHI R, 1911.

KNOWLEDGE.

445

from that of the uell-Unown Blow fly. and as this organ does
not take any active part in the process of bloodsucking, it
need not claim our attention here. The central blade of the
set of five lancets is the labnini, which in a specimen before us
measures •06-inch X -Ol-inch but tapers toward the extremity,
ending in two oval chitinous plates set obliquely on each side,
each bearing about sixteen rasp-like teeth, the central portion
between them being also finely toothed. The edges of the
labrnm are thin and sharp and furnished with delicate hairs,
whilst down the centre there is a groove, the upper end of which
is in commimication with the alimentary canal. Immediately
below this is the true tongue, or hypopharyn.x, somewhat
shorter and narrower than the labrum, slightly grooved on its
outer face, and tapered towards its rounded extremity. When
in operation this is pressed upon the inner surface of the
labrum and the grooves being then in apposition, form
a tube up which the blood is drawn. On either side
of these are the uiandihlcs, rather longer than the
labrnm and about the same width, formed of two ex-
tremely thin laminae and tapering to a lancet-shaped
point, the outer edges being smooth and sharp, whilst the
inner edges are bordered with minute teeth the forty-
thousandth of an inch in size. Outside these again are two
delicate blades which are generally regarded as the maxillae.
These are somewhat shorter than the mandibles, but are only
•004-inch wide, slightly tapering and rounded at the ends. If
these are examined with a magnifying power of, say, X150
or X 200, it will be seen that the ends are furnished with ten
to tw-elve rows of strong teeth pointing upwards, each tooth
consisting of a sharp point set in a socket of more flexible
material. A short distance from the end, where the maxilla
has widened to almost its full breadth, these large teeth give
place to a band of teeth of a smaller size, running down
either side, beginning in close rows of seven, but gradually
diminishing in number until they narrow to a single tooth,
leaving the central portion of each maxilla bare ; the inner
margin of each maxilla is smooth, but the outer edge is closeh-
fringed with long soft hairs almost throughout its entire
length. All the teeth point in the same direction, their use
being, no doubt — as in the case of the reflexed teeth on the
hypostome of a Tick — to enable the insect to maintain a firm
hold whilst sucking up the blood. The effects of the bites of
these flies vary considerably according to the state of health
of the person bitten, but the after irritation is often much
increased by portions of the mouth organs being broken off in
the puncture by a sudden attempt to crush the creature when
caught in the act. In many specimens which I have
examined, the partly damaged mandibles and maxillae seem to
confirm this suggestion. In some of the smaller species of
Tabanidae the diameter of the suctorial tube is obviously
less than that of a human blood corpuscle, and it is therefore
thought by many that the sali\a of the insect — probably
containing some form of formic acid — is injected into the
wound for the purpose of breaking down the red corpuscles to
enable their contents to be more easily absorbed ; luit in
answer to the question why are visitors so much more
persecuted than natives, it is asserted that the latter become
in a short time so inoculated with the poison as to be immune
to the usual after-effects, .is indeed is said to be the case with
bee-masters, to whom, after becoming similarly inoculated, the
sting of a bee merely means a momentary prick, ij q- r

CLARE ISLAND SUK\KV.— The results of this survey
are being published by the Koyal Irish Academy, and will
form Vol. XXXI of the Proceedings. When completed there
will be sixty-seven separate reports dealing with the flora,
fauna, geology, archaeology, and so on, of the Island and the
adjacent Mainland. We have before us Nos. 37, 51 and 52,
of these reports, dealing with the Arctiscoida — James Murray ;
Rotifcra (excluding Bdelloida) — C. F. Rousselet : Rotifera
lidelloida — James Murray. Until the commencement of the
Clare Island Survey, there appears to have been no previous
record of the occurrence of Water-bears in Ireland. Thirty-
three species were collected in the small area under examina-
tion, and it cannot be supposed that this list is fairly repre-
sentative of the whole of Ireland. When other parts of the

country are examined the list v i'l undoubtedly be considerably
increased. There are eleven species which are new
records for the British Isles, making the Britannic
list up to sixty-one specie?. An interesting feature of
the Irish list of water-bears is the occurrence of three
species which were recently discovered in Canada and which
were hitherto unknown in Europe : — Echinitscus intermedins,
Macrobiotiis occidentalis and M. virgatus. With the
Canadian Water-bears is associated in Ireland a Canadian
Bdelloid Rotifer — Callidina aspenila. These facts open
up some interesting questions in the geographical di,stribution
of fresh-water organisms. Are they cosmopolitan, given the
suitable conditions postulated by Mr. Rousselet in a recent
paper on the Geographical Distribution of the Rotifera ?

The Survey collected fifty-seven species of Bdelloids, besides
a number of very distinct varieties. As there were previous
records from Ireland of nine species, forty-eight are additions
to the Irish fauna. The study of the list in relation to the
world distribution of the species is instructive. There is not
a single species which is confined to Ireland. Xevertheless,
the Irish Bdelloid fauna exhibits much more peculiarity than
that one fact would seem to indicate. Much importance
attaches to the varieties of common species which are found,
these occuring chiefly among the spiny Bdelloids. in the
genera Dissotrocha, Pleuretra and Callidina. Mr. Murray's
reports are illustrated with his well-known skill.

A Course of eight lectures on "The Manipulation and
Theory of the Microscope" is being delivered by Mr. J. Edwin
Barnard. F.R.M.S., at King's College, Strand, The lectures
are addressed to advanced students of the University and to
others interested in the subject. .-Admission free, without
ticket. The syllabus shows that a very complete treatment
is aimed at, and the lectures cannot fail to be of very
considerable interest to students and others.

We have received Catalogue No. 2 from Messrs. H. F.
Angus & Co., Wigmore Street, W.. containing a list of second-
hand scientific apparatus and accessories. That part of the
catalogue devoted to the Microscope is divided under separate
headings, such as : Stands only, stands with objectives,
objectives and eyepieces, substage illuminators, and so on.
.\11 the instruments listed have been tested and adjusted where
necessary. It is proposed in course of time to issue a larger
list at periodical intervals.

A catalogue has also reached us from Messrs. Clarkeand Page,
Thavies Inn, E.C., of microscopical preparations, microscopes
and accessories which they supply. Their catalogue is now
issued in a much improved form to previous editions. We
w^ould dr.aw attention to Section .\ of their list of mounted
microscopical objects, a series of preparations mounted without
pressure in cells, in which a new fluid medium is used. .\11
these slides are particularly fine for dark ground illumination.
We have before us five of these preparations, of which we
would specially mention : Coralliiium nihnim,v.hh extended
polype, .\mbulacral disc and tulie of Echinus esculentus.
and the head of a Sand-wasp [Miscns sylvcstris). showing the
mouth parts. These fluid mounts are finer than any which
have hitherto come under our notice.

ORNITHOLOGY.

By Hugh Bovd Watt, M.B.O.U.

NEW NAMES FOR THE GREEN WOODPECKER.—

Amongst the vicissitudes of birds at the present time is the
peril of losing their old and honoured scientific names and of
having a fresh and unknown style conferred upon them. We
suppose that it is not within the scope of the operations of the
Society for the Protection of Birds to attempt to save the good
name of a bird, but, if it w-ere so. they might well intervene.
A new name is now proposed b.\- Dr. Ernst Hartert for the
English form of the Green Woodpecker viz. : — Picks viridis
pluvins. subsp. nov. With an unexpected regard for tradition
the justification is added, "because of the well-known ancient
superstition that its call is a sign of approaching rain." This

446

KNOWLEDGE.

NOVKMBF.R, 1911.

proposal is made in the course of a short article " On the
linglish and other Green Woodpeckers " in the current
number of British Birds (V. page 125). where the authority
above named distinguishes briefly five forms within Europe
alone. These are: —

1. Piciis viridis I'iridis L. Hirds from Scandinavia,

the greater part of Russia, and north-eastern Germany
(east Prussia).

2. Picus viridis pinctoniiu iRrehm.l Central I'uropean

birds.

3. The new name given above for English birds.

4. Picus x'iridis /ico/i((.s subsp. nov.. another new name:

given to Italian birds.

5. Picus viridis sharpci. Spanish birds.

Such is the transformation proposed in the present names of
Gcciiiiis 'ciridis (Linn.), and G. sJiarpii, Saunders, for the
Green Woodpecker.

THE GREAT BUSTARD IN NORFOLK IN 1900-1.—
The recent death of Mr. .Alexander Williams, of Jerez de la
Frontera. Spain, has given occasion to TIic Field (Kith
September. 1911) to recall his connection with the attempt to
re-introduce this species [Of is tarda) into one of its old haunts
in England. Mr. Williams collected in Spain skxteen (^reat
Bustards, and sent them to England, in the year 1900. when they
were turned out at Elveden. Suffolk, Lord \\'alsingham and
Lord Iveagh assisting in the project to re-establish the birds as
breeders. Some of the birds did manage to nest, and The
Field publishes a unique photograph of a nest in Norfolk.
The experiment was not in the end successful, the birds
surviving only for a limited period, some being killed in
a wanton manner and others straying and being lost.

The native British race became extinct probably in 183S.
when two birds were killed near Swafl'ham in Norfolk. In
eai-lier times the species occurred in the champaign parts of
Britain from East Lothian to Dorset, and being the largest in
size of our land-birds must have been a conspicuous figure.

A photograph of a recent Spanish nest can be seen in Col.
Verner's book '' My Life amongst the Wild Birds in Spain."'

ANOTHER NEW BRITISH BIRD— THE SLI-:NDER-
BILLED CURLEW. — The list of occasional bird-visitors to
the Bi'itish Isles continues steadily to receive additions, the
last reported being the Slender-billed Curlew, Xiiineiiius
tcnuirostris Vieill.. obtained towards the end of September.
1910. on Romney Marsh, near Brookland. Kent. Out of a
small flock occurring there, three were shot, one of which is
figured in British Birds for October. 1911. i\'.. page 1J4I.
with a brief account of the species by Mr. M. J. Nicoll. It
winters in the countries bordering the Mediterranean Sea and
breeds in Western Siberia. It has lieen met with rarely in
Heligoland, Germany. Holland, Belgium and northern France,
but not hitherto in Britain.

THE FULMAR'S BREEDING RANGE.— The Fulmar
Petrel (Fulinarus glacialis) is one of our native birds which,
happily, is spreading as a nesting species within the United
Kingdom. The latest new breeding localities reported are in
Ireland, on the northern coast of Mavo and on a cliff in Ulster.
(The Irish Naturalist. 1911. pages 148, 149-152, 152-154).
The original breeding station in the British Isles is St. Kilda,
and this was for long the only one place so known. Since
1878, birds have been nesting in F"oula, Shetland, and they
are now known in several localities in Shetland and also in
the Orkneys, where they first occurred as breeders in
1891. The first nests on the Scottish mainland were probably
in 1897, and some three different places there are reported to
be now frequented. Scottish islands on which the species has
within recent years commenced to nest arc Handa, Barra. the
I'l.annan Isles. Fair Isle, and North Rona. It seems justifi-
able to assume that this expansion means an actual increase
in the total numbers of the bird.

TWEED BIRDS.— The latest volume published in the fine
series of the '" Vertebrate Fauna of Scotland " is from the
pen of .Mr. .\. H. Evans, and entitled '" .\ F;iuna of Tweed "

(Edinburgh, 1911). It surveys the romantic region of the
Eastern Borders, including part of Northern Northumberland,
and the Fame Islands. The varied natural features of this
extensive district — islands, sea-shore, coast-lauds, lowlands,
valleys, glens, moors and hills up to the altitude of The
Cheviot (2676 feet) — secure an oriiis fairly representati\'e of
our native birds, ;dthough perhaps not so numerous in species,
as might be anticipated. Some two hundred and sixty-fi\e
different kinds (including eleven whose occurrence in the area
requires veinficationt are dealt with in the .\ves section of the
work (pages 52-2461. The accounts given of the (jrasshopper-
Warbler. Pied Flycatcher, Great Spotted Woodpecker. Barn
and Short-Eared Owls, Shoveler, Stock-Dove and Pallas's
Sand-Grouse may be singled out as particularly full of
information and interest.

BIRD-OF-PARADISE SINGING.— Mr. Walter Good-
fellow made the observation, when in Dutch New Guinea last
year with the British Ornithologists' Union Expedition, that
the King Bird-of-Paradise possesses a song which is sufficiently
melodious to command attention even were it to be heard
along with that of other birds recognized or classed as song-
birds. The songs of the natives of the country on the
Mimika River have a remarkable resemblance to this bird's
notes, and in\ari.ably end with the loud calls which it gives.
These may sometimes be heard from the birds kept in the
Zoological Gardens. London.

TERRESTRIAL MAGNETISM AND CARRIER-

PIGE(JNS. — In finding their way birds of passage are said
to be influenced by the magnetic meridian, and M. A.
Thauzies, a French specialist in carrier-pigeons, has given
some interesting information respecting their perception of
terrestrial-magnetic currents. -\t last year's Geneva Interna-
tional Congress of Psychologists he gave an account of his
twenty-three years experience and observation, which have
brought him to the conclusion that the sense of direction in
these birds is influenced by such currents.

.\s instances, on 22nd July. 1906, and ISth .-Vugust, 1907, the
results of numerous flights by carrier-pigeons were very bad.
Pigeon-fanciers, meteorologists and astronomers who were con-
sulted, could give no explanation. Marchaud, a specialist iu
electro-magneto research, found a solution by ascertaining
that on these two days an exceptional electric tension of the
atmosphere manifested itself in magnetic storms. Such
observations accord with the fact discovered by pigeon -
fanciers, that, with the great increase of wireless telegraphy,
much less reliance can be placed on carrier-pigeons. (See
" Sense of Direction in .Animals and the Magnetic Meridian."
bv Dr. K. Endriss, translated by L. R. S. Tonialiu. from
Dr. Jaeger's " Monatsblatt "I.

PMUTUGRAPHY.

L(_)W POWER PHOTOMICROGRAPHY F(^R
NWTURALISTS. — The ordinary photographer for the most
part is concerned with images which are very considerably less
than the objects, though at times he may do copying work up
to " same size," or life size. The photomicrographist, in turn, is
chiefly occupied with such magnifications as 50, 100, 500, or
1,000, or even 10.000 diameters in rare cases. But between
these two useful fields of work is a large region where
magnifications of 2, J, 4, and so on, up to, say, 10 diameters is
of peculiar interest to the naturaUst. In a word, what the
naturalist in the field can see with au ordinary pocket magnifier
or Coddington he would like to be able to record perm;inently
by means of photography with the minimum expenditure of
labour and outlay for special apparatus.

Having made a considerable number of experiments iu this
low magnification region I propose to set forth in detail some of
those aids which are easily home-made and have proved useful
and practical. It is here assumed that the worker pos.sesses
an ordinary field, or bellows camera, lens, and tripod, and is
familiar with the usual procedure of negative-making.

Figure 1 shows a ipiite simple and cfi'ective expedient !ny

Novi;mber. 1911.

KNOWLEDGE.

447

holdini; a camera vertically over such a small object as a
flower. This is laid on a sheet of gray non-shiny, but not very
rough, paper, and supported at a convenient height above the
floor b\- a box. pile of books, and so on. The camera is held
in the position shown by tying the tripod legs to the top rails
of two chairs. 1 he sheet of white cardboard on edge between
the box and chair is used as a reflector to prevent the object
casting too dark and detail-less shadows. This method also
serves conveniently for copying maps, plans, diagrams, and so
on, in books. The photographic reader will scarcely need to
be told that to copy "same size" the lens will have to be at
double its focal length from the ground glass, and also this
same distance from the object.

To find the lens-to-image distance for any magnification,
e.g.. 4 times, we add 1 to 4 getting 5 and multiply this by the
focal length. Thus with a ft-inch lens and J diameters
magnification the lens to image distance is 3 plus 1 times 6.
or 24 inches. While the leits to object distance is one third
of 24 or 8 inches. It will thus be seen that in this field of
work our limit of magnification depends on the relationship of
focal length of lens to camera bellows length. Thus to find
the greatest magnification with a 12-inch bellows and 4-inch

U is a loose piece which slips over the top of the upright par
E, and it forms a shelf (Figure 3). These two nioxing
pieces are made out of the wood of an old cigar box, and cigar
box nails.

i- II .L KI-. 1.

lens we divide 12 by 4 and get J. Then subtracting 1 we get
2, or the maximum magnification \\ith a 4-inch lens and
12-inch camera bellows is 2 times i.e. double life size.
Finally, requiring to know what lens will give us 10 diameters
magnification with a 24-inch camera bellows we add 1 to 10
getting 11, and then divide 24 by 11 getting 2rr, as the
maximum focal length, so that to be on the working side we
should limit our focal length to 2 inches. The above scraps
of simple arithmetic must be kept in mind whenever we are
fitting up home-made contrivances of the sort to be herein
below mentioned.

I now turn to an easily-made apparatus (Figure 21 that I
have had in use for many years with complete satisfaction.
It is especially well adapted for small objects, e.g.. shells,
fossils, seeds, and so on, which can be stuck to a card, or
small enough to rest on a quite narrow (half-inch i shelf.

F~igure 2. — A, the top of an ordinary tripod stand. The
camera screen is attached to the under-side of the triangular
top by means of a cheap steel watch chain with swivel end.
which engages with a ring passing through the pierced head of
the camera screw. This prevents the camera screw from being
lost. BB a straight grain piece of (teak) wood, say three feet
long by four inches wide by half-an-inch thick, which acts as an
extension and base board. The camera screw passes through
its usual hole in the tripod top, then through a hole in BB,
and finally enters the " bush " let into the base of the camera.
These three parts now become as one solid piece on tightening
the screw. CE is a loose piece (see Figures 3 and 4)
which slides along BB.

F'IGIIRE 2.

At F we see the plate end of the camera, but the re\ersing
back and focussing screen have been removed, so that we
may see a contrivance which enables ns to use the right and
left-hand halves of a quarter-plate for two different pictures.
This effects economy of material (cost), time, and storage
space when we are — as is often the case — concerned with
images which occupy only a small fraction of a qnarter-plate.
(The two figures 3 and 4 were thus taken side by side on one
ipiarter-platel. The contrivance consists of a piece of card-
board, blackened on both sides. It is of such a size that one
can bend and spring it into the last groove of the camera
bellows just inside the camera body. When it is pushed as
far as it will go to one side, it is just big enough to obscure
half the focussing screen, so that when pushed to the other
side it similarly obscures the other half. The procedure
is: (1) push the card to right; (2) focus on the left half of
screen ; (3) insert the plate holder, expose, close the slide and
withdraw it from the camera ; (41 push the card to the opposite
side ; (5) focus on the other half of the screen for the second
picture ; (6) insert the plate holder, expose, close and withdraw
it. and so on. We have now two image exposures on the plate-
side by side.

I'IGIIRE 3.

•'u.UKi': 4.

Figures 3 and 4 show the two sides (front and back) of the
sliding object holder. Figure 3 shows the shelf, I), slipped over
the upright part, E, and held in place by a drawing pin below
D. A small shell rests on a piece of paper to serve as a back-
ground, G. Figure 4 shows a small shell stuck to a piece of
card which is held in place by a drawing pin, H. At K we

44S

kxu\\li:dge.

November. 1911.

have a small piece of white card pinned to the edge of the
upright wood. This ser\es as a reflector and prevents the
shadows being too dark.

The special points .about this easily made piece of apparatus
are that it calls for no alteration of the camera in use. though
one may have to buy an extra long camera screw ; and it
enables one to move the object and camera together, so as to
get any kind or direction of lighting. If a passing vehicle sets
up vibration in the room where work is going on the whole
apparatus is equally affected. _
so that the definition docs not
(apparently) suffer.

Figure 5 shows an ordinary
result obtained by this contriv-
ance. Figure 6 shows us a life-
size view of two cowrie shells
stuck on a card [vide Figure 4).
Figure 5 shows us a magnified
image, enlarged about 7 dia-
meters, of one of these shells.
It may be of interest to say at
once that the negative of Figure 5
was taken not with a lens, but
with a "pinhole" (/.c. made
with a needle) in a thin piece
of sheet copper. This sheet
metal, obtainable from any metal
dealer, is about the thickness of
a thin visiting card. A circular
piece is cut as an easy fit to the
inside of the lens tube. The
glass parts of the lens are un-
screwed and laid aside. Thi^
disc of metal is pushed up insidt
the tube so as to rest against the
stop or diaphragm, and the centre
pierced with a No. 1 needle.
The hole which passes the fattest
part of this needle is about
.i'„-inch in diameter. In this case
tlie hole was about 14 inches
from the plate and about 2 inches
from the object. Although a
pinhole does not give the

definition sharpness of a lens at its best for any one plane, yet
the pinhole give us a certain evenness of soft definition which
for some objects is particularly effective. In photographic
parlance, the pinhole gives us great depth but poor definition.
.\s a matter of fact this nV-inch hole is too large for best pinhole
definition at 14 inches. .\t this distance we slionld get a
sharper effect with about ;jV-inch hole. i.e.. a No. 5 needle. The
reader, will of course, understand that a good modern 2 -inch
lens, duly stopped down to say F.44 would have given a sharper
picture over a certain depth of subject, but would have
brought into prominence the differences of definition of the
various planes in an unpleasant way. This more or less hemi"
spherical subject was chosen as typifying a markedly difficult
case as regards depth of subject, and thus showing that at
times leg. fossils showing form rather than detail) the
homely pinhole gives a more effective rendering than the
costly lens. I emphasise this point because tlie use of a pin-
hole for this class of work is practicalK- unknown to most
workers.

The following table shows one the best size of hole for
sharpest definition at various plate distances : —

Plate Distance 6 8 10 I.t 20 JO inches

Diameter of Hole ... s'„ A ;V .h. -S ■/.. •■
Number of Needle... 9 8 7 .t 2 1

The sizes of needles of various numbers vary slightly among
different makers ; but the above sizes, which are those of
Mil ward's Sharps, may be taken as generally representative.

Of course, exposures with a pinhole are much longer than
with ordinary lens apertures ; but. beyond the matter of
patience, this is of no account with non-moving objects.
.Although it is wrong in theory, yet it works out all right in
practice to base exposure on the F. value of the pinhole. Thus

Figure 5.

a hole iV"" inch diameter, at 10 inches from the plate, may
be reckoned as F.400.

To compare this with a lens working at F.32, for instance :
the squares of 52 and 400, viz., 1,024 and 160.000 are roughly
1 to IfiO. so that ten seconds with F.32 would be equivalent
to (about) twenty-seven minutes. But as a little extra
exposure is better th.ni under exposure one would in such a
case give thirty nuiiiitc;.. There is the further consideration
with pinhole expni-ures. \ i/.. that the occasional periods of

\ ibration due to passing vehicles
are usually negligibly small in
comparison to the total time nf
exposure.

F. C. Lambert.

M.A., F.K.P.S.

PHY.SICS.

Hv Alfred C. G. Egerton,
B.Sc.

ol'llTfl AI.MIA elec-
tric a. — L. Bell has published
recently in " The Proceedings of
the .American .Academy" an
investigation on glasses used as
a protection against the injurious
effect of light on the eye.
Bacteria are rapidly killed by
radiations of a smaller wave-
length than 270 A^M in the ultra-
violet, while the ultraviolet radia-
tions are absorbed by air con-
siderably if less than 230 /J-t^, and
by glass if less than 310 MM. The
symbol is an abbreviation for a
micro-millimetre or one-millionth
of a millimetre ; thus the wave-
lengths of the ultraviolet region
range from about three hundred
and sixty millionths to about one
hundred millionths of a millimetre
in length, shorter than which they
are so readily absorbed that
they have not yet been measured. All ordinary glasses absorb
the ultraviolet rays which have cell destroying power or
bactericidal effects. Common amber-coloured glass cuts oft'
all the ultraviolet region. In contra-distinction to this a yellow
filter of gelatine soaked in dimethylaniline permits some of the
longer ultraviolet waves to pass, but cuts off a large portion of
the visible region, and can, in conjunction with other screens,
cutting oft" the yellow {e.g.. cobalt glass), be used to filter
through the ultraviolet rays.

.Arc lamp workers, and those that work electric furnaces.
which, by the way. are in use now for preparing high grade
steel from rich Norwegian ores, are rarely affected by true
" ophthalmia electrica " chargeable to the ultraviolet rays, but
are very often affected by the intense luminous radiation. The
vitreous humour and crystalline lens of the eye is capable of
absorbing most of the ultraviolet radiation, but there appears
to be some particular wave-length which gets through rather
easier, and is apt to cause trouble. The remedy is to wear
glasses when dealing with arc lamps or quartz mercury vapour
lamps; while, to prevent the injurious effect of the hnninous
radiations, glasses should be slightly tinted.

It is interesting to compare the transparency of quartz,
uviol glass and an ordinary photographic lens to ultraviolet
waves. The photographic lens does not let through waves
shorter than 365 mm. while uviol glass, a glass made in the
Schott and Genossen works at Jena, allows through light of
265 /J-p- and quartz even shorter waves.

SliLENICM. — This element exists in se\eral modifications
called in the language of the chemist, allotropic forms.
There is a red amorphous form, a grey crystalline form and a
darker, almost black, form. .Ml these three forms, though

Figure 6.

XOVKMBER, 1911.

KNOWLEDGE.

440

differing in their physical properties, are one and the same
chemical substance thougli the atoms may. perhaps, be com-
pounded into different sized molecules in the various allotropic
forms. They differ in their electrical conductivity among other
physical properties. Selenium cells have been constructed
which are sensitive to light ; when exposed to light the
electrical conductivity decreases considerably. The selenium
in this sensitive state contains at least two of the allotropic
lorms. and the light changes one form into the other, the effect
being reversible when the light stimulus ceases. Metallic
selenides, in small quantity, seem to improve the sensitiveness
of the selenium. Selenium cells are constructed by com-
pounding films of selenium with mica sheets, or between wires,
or the selenium may be condensed on to a cold surface, in which
case it possesses very little inertia and attains its maximum
or minimum conducti%ity very (juicUly and without showing
inertia as in the case of ordinary fused selenium. Selenium
cells have been used as receivers for wireless telephony.
Riihmer succeeded in telephoning along a fluctuating light
beam over ten miles. A vibratin.g membrane controls the
beam of light and causes it to fluctuate in intensity according
to tlie intensity of the sound vibrations. The selenium at the
other station receives the beam of light and alters its con-
ductivity according to the intensity of the li.ght falling on it. A
telephone connected to the selenium cell is thus affected
according to the fluctuation and intensity of the current and
of the light beam and therefore of the voice transmitted.

Kontgen rays affect selenium just as light does — yellow light
is most active. Some years back I made a few experiments
on this point hoping to get a very marked effect with Rontgen
rays owing to their penetration throughout the mass of the
selenium. The change in conductivity is considerable, but no
comparisons were made of the energy in the Rontgen beam
with that in a light beam producing equal change in con-
ductivity, and so the results were only of small value. The
idea was to try other allotropic substances — such as tin,
to see if they were influenced throughout their mass, liy X rays,
whether they would possess similar properties to selenium.

Another substance of considerable interest as regards
electrical conductivity is silver sulphide which, as Faraday
suggested, possesses a negative coefficient of resistance, i.e.,
its resistance decreases as the temperature rises. \Vhen first
heated the resistance decreases rapidly ; but as it cools,
though it does not return to its original hi.gh resistance, yet the
resistance is greater than when hot ; after considerable heating
and cooling the resistance does not alter much on further
subjection to change of temperature. The author, H. V. Hayes,
of recent work on this peculiar substance, seems to infer that
the temperature coefficient of resisLiUce of silver sulphide is
not really negative, but that the apparent effect is due to
imperfect contact at the junction of the leading-in wires and
the silver sulphide.

RADIATIONS FROM LATFX OF EUl'IIORIilA
PEPLL'S. — Chapman and Petrie find that the latex of this
Australian spurge possesses the property of aft'ecting photo-
graphic plates through paper, or even through aluminium foil.
The latex seems to give off a penetrating radiation which must
be comparable in intensity with the radiation emitted by
uranium or thorium. It has been found that many substances
affect the photographic plate, the eftect in some cases being
due, perhaps, to hydrogen peroxide ; in other cases, and more
conunonly, to the production of ions in the neighbourhood of
the substance, either by radiations from the substance or by
a chemical change induced by moisture or other causes on the
substance. It has been found to be quite difficult to obtain a
paint to inscribe the numbers on the black paper in which
films are rolled owing to this phenomenon. This particular
latex, however, seems to possess the property to a remarkable
extent.

R.'^DIATIONS. — When describing in one of our recent
issues the instrument by means of which Professor Wood
was able to isolate ultra-violet waves free from \ isible rays, I
mentioned that it was also a convenient method of isolating
long heat waves. Professor Rubens has been able by means
of such a quartz lens apparatus to isolate waves one-third of

a millimetre in length Iron, the radiations emitted by an
intense mercury vapour lamp. Now visible rays at the
extreme red end of the spectrum are less than inVxr of a
millimetre in wave-length, while very short electro-magnetic
waves of only a few niillmietres in length have been produced
by Fessenden and others. The conijilctc range of ether
vibrations has thus been nearly brid.gcd experimentally. It
appears quartz is extremely transparent to these long heat
radiations. Diamoiid, selenium, amber, paraffin and vulcanite
are fairly transparent, much more so than to the one-tenth of
a millimetre waves, which can be isolated from the Auer-manlle
radiations. Such invisible radiations are detected by means
of a bolometer or radiomicrometer. The first is a small
black very thin strip of platinum or silvered platinum, which
alters its resistance when radiations are absorbed by it : two
such strips of equal resistance are placed close to each other
and an electric current is made to pass down each strip — their
resistance being the same, the current in each branch will be
the same ; if the resistance of one be altered, then the current
in one strip is greater than in the other, and so an efi'ect is
produced on a galvanometer connecting the two branches of the
circuit containing the two strips. The radiomicrometer is
an exceedingly delicate thermopile. When a junction of
cadmium-antimony and bismuth-antimony is heated an
electromotive force is set up which tends to drive a current
down a wire connected to the two. In the radiomicrometer.
a silver strip is situated between such a junction and the two
ends of a silver wire are connected to the two alloys and the
wire is looped so as to hang vertically from a quartz fibre
inside a copper tube between the poles of a permanent magnet.
When the radiations, say of a candle placed 10 metres away,
fall on the blackened strip of silver, a current passes down the
loop, and the magnetic action is such as to turn the coil, which
motion is registered by a spot of light mo\'ing over a scale.

Langley, by means of the bolometer, mapped the infra-red
spectrum of the sun to nearly a wave-length of .jju millimetre,
but below this the radiations are absorbed by the atmosphere.
He was also able to estimate from an examination of the
moon's r.adiation that the temperature on its surface was less
than O'C. Sir William Abney succeeded in photographing,
the shorter infra-red rays. Bathed plates, to photograph
objects in infra-red light, can now be bought commercially, but
they do not record a wave-length of more than rij\,T_; millimetre.
Such plates are bathed in dyes (.-Vlizarin blue. Nigrosin, diazo
black, cyanin, and so on) which absorb red rays. The energy
of these rays go to change the constitution of the sensitive
emulsion, and a photographic record is the result. Now
.■\bney conceived the idea of making silver bromide absorb red
li.ght instead of blue light as is usually the case : he succeeded
in obtaining an enmlsion of silver bromide which transmitted
blue light and absorbed red, and the plates he thus- made he
employed to photograph waves of even sJrr millimetre. P. V.
Hevan has recently investigated the absorption and dispersion
of light by alkalinietals — that is, by potassium, rubidium,
lithium, caesium and sodium. The measurements are somewhat
difficult to carry out with such metals owing to the fact that
they attack most materials with which they come in contact.
Lithium vapour even attacks steel tubes. It appears from this
work that different specialised atoms are absorbing different
spectral lines, so that a certain percentage of atoms in the
vapour may be employed in absorbing one particular wave-
length of the incident light, while another is absorbing another
wave-length. This idea is distinct from the idea that within
each atom the electronic arrangement is such that certain
groups of electrons are responsible for the absorption of the
\arious incident radiations. .An electric current passed
through such vapours of metals under diminished pressure
gives rise to a varietj' of spectra akin to flame, arc and spark
spectra according to the electric conditions. The luminosity
of the vapour of sodium will mask the spectrum of helium
when present in such tubes. The masking effect of the
spectrum of one substance on that of another is a matter of
great interest.

The salts of potassium .are radio-active ; they emit a
penetrating radiation, which appear to be of corpuscular
nature like part of the radiation (/^ rays) from radium.

450

;XO\VLEDGE.

XOVEIIBER. 1911.

Rubidium likewise emits a less penetrating radiation, but
caeciuin, which is so akin to rubidium chemically, does not
appear to do so. unless such particles arc niovini; too slowly
to be detected.

Kadio-activity has now developed to such an extent that the
knowledge of its processes leads it now to he applied to the
elucidation of many problems of a less specialised character.
Professor Rutherford has recently thrown much light on the
structure of the alom. by a theoretical investigation of the
.action of the o and ,i particles penetrating an atom, while
his theoretical deductions are well backed up by the ex-
periments of Geiger and Marsden and Crowther. Mr.
Marsden is likely to give to readers of " Knowledgk "
an account of this work, and I will therefore only indicate
the nature of Rutherford's theory. He starts by assuming
the atom to consist of a central nucleus with a charge
C(iual to the number of electrons multiplied by the charge on
each (4-65 X 10"'" electrostatic units), while there is an outer
shell carrying an equal and opposite charge. He investigates
what would happen it an a particle la positively charged atom
t>f heliumi emitted, say from Radium C. were to penetrate
such an atom, and what the chance would be for a large
deflection of such a particle. He finds that when the a particle
penetrates very close to the central nucleus, its deflection will
be very large and it may be deflected 150° or so, back towards
the direction in which it came. It appears from experiments
on the percentage of particles deflected at various angles, or
measured by the number of scintillations occurring in unit
time on a zinc sulphide screen placed to receive them, that
the number of large deflections is greater than would be given
by an atom of such a character that the large deflections
would be made up of a number of smaller deflections. This
effect no doubt does occur to some extent, and especially with
the lighter (i particles, which, although moving more rapidly,
do not possess so great energy as the a particles. Professor
Rutherford's theory of the central condensed charge in the
atom explains well the experiments on the diffuse reflexions of
a particles, on the variation in the percentage deflection at
different angles with the atomic weight of the reflecting atoms,
on the average scattering of the rays produced in penetrating
thin plates of various metals, and on the scattering of ii rays
of different velocities by atoms of different weight. The outer
charge of the atom is probably that of a number of electrons
moving as satellites to the central charge. This idea is similar
to the theoretical idea of the atom worked out by Nagaoka.
which was something of the nature of a minute planet Saturn.
It is likely that this scintillation work will give much informa-
tion on the structure of the atom. The problem is akin to
that which would present itself to a philosopher living outside
the solar system, and who wished to investigate the structure
of it by the orbit and perturbations of a comet passing through
the system. But in our case the comet or a particle is more
under control.

ZOOLOGY.

By Pkoikssok J. Arthl'K Thomson, M..\.

THE LIVING EARTH.— It has been shown by Drs.
Russell and Hutchinson, of the Rothamsted laboratory, that
soils heated or treated with certain volatile antiseptics, and
brought again under conditions favourable to plant growth,
show a great increase in fertility. The soil bacteria are
first reduced in numbers and then they increase enormously.
To this increase is due an increase in the production of
ammonia in the soil, and to this the greater fertilit\'. But
why should the decrease of bacteria be followed by their great
increase ':

To explain this it has been suggested by the authors named
that the treatment with volatile antise|)tics kills off the
protozoa of the soil, some of which feed on bacteria, and
thus limit their increase. The protozoa arc more susceptiblc-
Ihan the l)acteria to the sterilising agents. When they are
killed off the bacteria multiply without this check. But our
knowledge of the protozoa of the soil is someuh.it scanty and
vague.

\\"e welcome therefore a recent investigation by Mr. T.

Goodey. in which he names about thirty protozoa found in
cultures of soil. Ivighteen of these are ciliated infusorians.
and in regard to these Mr. Goodey comes to the interesting
and important conclusion that they exist in the soil in an
encysted, not in an active state. " In consequence, they
cannot function as the factor limiting bacterial activity in the
soil."

HOW LONG DO WHITE MICE CARRY THICIR
VOUXG? — One would have thought that a simple (juestion of
this sort admitted of ready answer. The usual statement is
that the period of gestation is twenty-one days, the same as the
period of a chick's development. But J. Erank Daniel reports
that there is great variability in the duration of the period —
in different mice and in the same mouse. I'or non suckling
mothers a definite gestation period of practically twenty days
may be stated : and this holds true irrespective of the size of
the litter. But for suckling mothers there is great variability,
from a minimum of twenty-two days to a maximum of thirty
days. .-Xnd it seiuns that the period of gestation in suckling
mothers varies directly with the number of young suckled.
The "how" of this relation, if it is a well-establislied relation,
remains uncertain.

BITEOE HEU )DERMA.— The virulence of the venom of
the Gila Monster, the poisonous lizard of Mexico and Arizona,
has been often proved in the case of small animals, but we
have little precise knowledge of the effect of the poison on
man. This gap has been filled by the careful observations of
Mile. Marie Phisalix. who was accidentally bitten while
examining the lizard's mouth. She describes the intense
pain, the swelling, the profuse perspiration, the giddiness, and
other disagreeable results of the bite. Even after a week the
fatigue, the giddiness, and the local pain had not disappeared,
but no serious consequences ensued.

SLOWING DEVELOPMENT OF HERRINGS' EGGS.
— One of the methods suggested in order to secure the intro-
duction of the herring into New Zealand waters is that of
lengthening out the period of embryonic development, so that
transportation of the eggs may perhaps be effected before
hatching occurs. Dr. H. Charles Williamson was able some
time ago to lengthen out the period of embryonic development
to fifty days. He did this by lowering the temperature, which
probably makes the formation of nuclein-compouuds slower,
and therefore retards cell-division. His further endeavours
to extend the period have not been successful. Lowering the
temperature still further slows the development so unich that
it is very apt to stop altogether.

THE HIBERNATING SNAIL. — It is interesting to
connect the internal and external periodicities, and there is
a great deal of interesting work to be done in comparing the
details of organic structure at dift'erent times of year. Taking
the common Helix poiuatia, Spiro has recently shown that
the granules and drops of fat which are abundant in the
summer in the cylindrical cells lining the alimentary canal
are all gone in winter ; that the nuclei of these cells become
poorer in chromatin : that the cilia which all the cylindrical
cells have are lost. There is another kind of cell in the lining
membrane, vase-like in shape, which secretes nmcus in
summer during digestion, but, of course, ceases to do so
when hibernation sets in. We thus get the impression of
the depth of the organism's reaction to the seasons. It is
also very interesting to find that the whole lining of the
alimentary canal is renewed in spring before the nutritive
period of the year re-commences.

H.ABITS OE SCUTIGERA.— J. Kunckel d'Herculais
has been studving the well-known long-legged centipede called
Sctitigcra colcopfrafa which is common in houses. It is
famous for the disproportionately long limbs, fifteen pairs in all,
for its compound eyes, .and for many other peculiarities, but
what Kunckel d'Herculais calls attention to is its activity
as a fly-catcher, DLiriug the day it lies quiet in crevices
about the doors and windows and flooring, .At night it goes
on the hunt and kills large numbers of flies, e.g.. Fannia
scalartH. It throws itself upon the fly, enwraps it in its

Novkmbi;r, 1911.

KNOWLEDGE.

451

postei-ior limbs, and injects the instantaneously paiulvsiiiL;
venom from the forceps. It sometimes kills thrc:e or finii'
without stoppini,' to eat. The dead liodies are masticated, lint
only the soft parts arc ingested.

.ASS()CL\TI()NS.— Professor Ch.irles Chih(.n. of Canter-
bury College, New Zealand, has recently described some
interesting examples of what he calls "commensalism," — a
term which should, we think, be restricted to cases of
mutually beneficial external partnership. One of these cases
is th.at of a crab iParaiitithrax loiigipcs). which seems to be
alnn)st invariably accompanied by specimens of Balaiiiis
dccorus growing on its carapace, the cirripedes being in some
cases so large and numerous that they exceed in size the body
of the crab itself. Here we have to deal with an " epizoic
association." probably quite unimportant in its initial stages,
but gradually, as the cirripedes grew, becoming inimical to
the welfare of the bearer.

The second case is that of a hermit-crab ilinpagurus
steu'arti). which has a straight abdomen, and inhabits tubes
formed bya Millcpora, or, in other cases,"a massive calcareous
I'oKvoon. which is very much larger than the crab, so nmch so
that it seems doubtful if the crab can drag its large, solid
dwelling-place about with it." Professor Benham has suggested
that the cylindrical cavity inhabited by the crab may be due
to the decay of a branch of seaweed around which the Millepore
or the Polyzoon grew.

Some of the associations that have been reported from time
to time are very remarkable, and Professor Chilton refers to
Dr. .Mcock's description of the intimate commensalism between
an Indian Ocean hermit-crab, (Pagtiristcs typica), and a
sea-anemone of the genus Mainillifcra. The sea-anemone
settles on the hinder part of the young hermit-crab's tail, and
the two animals grow up together in such a w-ay that the
spreading anemones " form a blanket which the hermit-crab
can either draw completely forward o\cr its head or throw
half back as it pleases."

BEE DLSE.'XSE.— We notice that Dr. H. B. Fantham and
Dr. Annie Porter have found bees and combs, from
Cambridgeshire and Hertfordshire, infected with the Micro-
sporidian (Noscnia apis) which was found by Zander in
Bavarian bees. This parasitic Protozoiin belongs to the same
genus as the organism which causes pebrine or silkworm
disease, and the authors think that it has been responsible for
a good deal of the " bee disea.se " of recent years. It causes
a sort of dry dysentery. Infection occurs by means of spores,
as was experimentally proved. Unluckily, the only certain
destructive agent is fire. It nmst be noted that according to
Dr. Maiden there is also a bacillary infection in bees, the
parasite being called BacillKS pest i form is apis.

A TELL-TALE C.4RTILAGE. — In the inner upper corner
of our eye there is a minute half-moon-shaped fold, the Plica
sail iliiimris. .m item in that museuin of relics of past .history

which we carry about with ns in our body. For it corresponds
to the third eyelid I in whole or in [)artl which is well-developed
in mo^t mauuuals and helps to clean the eye. It is vestigial
nut (inl\- in Man, but in Monkeys and in Cetaceans. Its
practic.d absence in the Cetaceans is compensated for by the
continuous washing of the eye with wati-i. and in the other
cases to some extent by the frequent inovetnents of the upper
eyelid. It seems to be a very old structure this third e\'elid,
for it is the " nictitating membrane" that is flicked across the
e\e of birds, and it is also represented in most Reptiles.
What prouipted these remarks, however, was not the Plica
seinihinans itself, but a minute cartilage which it sometimes
includes even in Man. This is a great rarity in white races,
occurring in less than one per cent. Giacomini found it in
four cases out of five hundred and forty-eight whites. But
he found it twelve times in sixteen coloured people, and
Adachi found it five times in twenty-five Japanese. Dr. Paul
Bartels has recently examined twenty-five South African natives
(eight Hereros and seventeen Hottentots) and has found the
cartilage in twelve. Now as the cartilage is found in all .'Vpes
and Monkeys it seems fair to say that, so far as the cartilage
of the third eyelid vestige goes, some races are more thero-
morphic than others. — more conservative of their historical
relics.

YE.ASTS OF INSECTS. — We are continually impressed
with the inter-relatedness of organisms in the web of life, and
an interesting fresh case has been recently reported by Dr.
Karel Sulc. He has been studying accumulations of reserve
material which occur in ."Xphides, Scale-insects, Coccids, and
related insects, and finds circumstantial evidence of a wide-
spread symbiosis between the insects and various specific
yeasts of the Saccharomyces type, which seem to work out
changes in the stores within the body.

SENSE OF DIRECTION IN THE BLIND.— It is well
known that most blind people become aware when they are
approaching an object or even when an object is very quietly
brought near them. There has been a great deal of specula-
tion and not a little experimenting concerning this sense, which
has received many names — sense of obtacles, facial perception,
sense of direction, feeling at a distance, and so on. The
accounts that the blind themselves give of their perception
are very contradictory. Some investigators have regarded
the sense as a fine facial touch-sense, others as due to heat-
waves, others as sensitiveness to changes of pressure in the
air, others as auditory. Recent experiments of an ingenious
kind made at the Institution for the Blind in Paris, ha\e led
M. Truschel to the conclusion that the perception is of an
auditory nature and due to the fact that the object reflects
and alters surrounding sounds. To the objection that a deaf-
mute has been reported as showing the power, he answers
that those deaf to music and speech are often sensitive to
very feeble noises.

By using ball-bearing rollers
the force of gra\it>' may
be utilized for conveying
bricks a long distance for
loading on cars as shown
in the accompanying illustra-
tion (Figure 1). No hand
laboiu' whatever is required,
and no power is utilized
with this carrier system,
which takes advantage of
gra\'ity to do the work.
The bricks are simply placed
on the carrier within the
kiln and they are started
on their \\ av to the car.

AJADING BRICKS V>\ (,RAVITY,
Bv FK.\NK C. I'ERKINS.

where they are loaded by
another operator and placed
in position for shipment.
The friction is so small
on the ball bearings of the
rollers that only a very
slight incline is necessary
on the conveyor system to
automatically carry the bricks
long distances, and the
\arions sections of the con-
\'eyor may be shifted as
desired, the material to be
liiaded taking single and
double curves when necessary
without difficultx'.

SOLAR DISTURBANCES DURINCx SEPTEMBER, igii.

I'KAXK C. DENNETT.

Di;king September the Sun's disc .ippeared to be without
disturbance, bright or darl;. on the IJth. 15th to 20th. 25th and
JOth. .All disturbances after the lOth were faculic only. The
lonfj'itude of the central meridian on September Ist was
325= 45'.

No. 36. — The only spot disturbance during the month. It
was first seen as a moderate spot, about eleven thousand miles
across, with a bright bridge over its umbra, on September the 1st,
and a trail of spotlets extending towards the North- East. The
bridge over the umbra was an interesting object until the 6th.
and on the 5th it showed complicated detail, and was double
in a part of its length. On this date the spot seems to have

faculic knot show(^d just ahead of the group in which pores
appeared to be dc\eloping. but it disappeared again. The
group sometimes presented a very interesting appearance in
the spectroscope. On the 1st the Ha line showed displace-
ments both on the red and violet sides, with dull reversals,
wtiilst the D:i line of helium was seen dark. Next day the
distortion was less, but small dark hydrogen flocculi were
visible around, as w-ell as small projected prominences. ( )n
the 5th a pale prominence in the rear of the leader was visible,
and also small dark hydrogen flocculi. with the helium line
showing duskv.

The dotted areas in the diagram show the position of

DAY OF .SEPTEMISHR, 191 i.

?5

24

^3

2?

^1

2,0

1?

?

T

If^

6

14.

13

2

II

\Q

?

8

7

f

5

4-

i

30

2 2i

1

.8

27

26.

JO-

Iff

s.

ItV

■:

0

1— .

0

J

.■ j»

Cv

-'

N

36

» vO

N

0' 10' 20' 30' W 5C' 60' 7Cr 90' 90" lOff HO' l?0' 130" 140" ISO' W (7(3' 'W 190' JOO' 210" 220' 230' IW 250" 260' 270' 280" 290" 300" 310" 320" 330" 34-0' 350" 360"

attained its greatest area — fifteen thousand miles by elev n
thousand miles. From the 1st until the 7th. the inner edge
of the penumbra appeared to be fringed more brightly, and
on the 7th and Sth. the bright photospheric substance
broke through the penumbra on the southern side. On the
10th. the place of the spot was marked by three closely
packed umbrae which had disappeared by next day, the
site being marked by faculae seen also on the 12th. On the
2nd the three more distant spotlets had broken into one
with a long umbra, which again broke up very quickly. The
pores were subject to rapid change. On the 4th. 6th and 7th.
a little pilot pore was evident just west of the leader, and on
the 6th and .Sth. pores showed a little towards the south. The
maximum length was fiftv-six thousand miles. ( )n the 2iid a

faculic disturbances. I\aculae were seen on the 1st and
2nd near longitude 256 . X. latitude 50°. and 26". N. ii°. On
the 1st, 2nd and 12th near 260°. S. 13°. On the 4th and 5th.
at 225°. S. i ■. another at 215=. S. 15'.on 4th, with another at
202°. S. 4°. on 5th and 6fh. The group at 320°— 340°. S. 13"
— 20° were visible September 22nd to 24th.

Notwithstanding the fewness of disturbances visually seen
upon the disc, there are still a fair number of prominences
around the limb. On -the 24th there were a number of
eruptions recorded showini; '#!at the chromosphere was in a
very active condition.

The Chart is constructed from t'^e observations of Messrs.
1. McHarg. .\. \. Bus^. E. E. Peacock, and F. C. Dennett.

NOTICES.

ML'SEUM WORK.— Particulars of a
vacancy for a pupil (who will be paid a
small salary) in a nuiseum, can be obtained
on application to the Editors of " Kxow-
I.EI1GK," at 42, Bloomsbnry Square,
London, W'.C.

CHEMICAL ALPAKATUS.— We have
received from Messrs. Gallenkamp and
Company, Limited, Part 1 of their
catalogue of General Chemical Apparatus
and Laboratory Accessories for the Session
1911-12. It measures seven by clc\cn
inches and consists of more than eight
hundred pages. Messrs. Gallenkamp claim
to have the most varied stock in England,
and their price list is certainly excellent
e\-idcnce in favour of this contention.

HORTICULTCRAL HOOKS.— Messrs.
John W'eldon & Company's Catalogue of
Gardening Books and Papers, which has
jiisl reached us, contains no less than one
thousand and eighty-five items and should

l-'rnnr a />hi>li>t:' II/--1 i-y U. /•'. Ilt'iiy.

A Gibraltar .Ape.
452

prove exceedingly interesting to all who are
occupied in the art which we are told
" doth mend nature."

HARBAKY APES AT GIBRALTAR.
— In Tltc Sclbonic Magnsinc for
N'i>\'eiiiber, Mr. (L B. Hony gives the
following account of the .Apes of Gibraltar.
He says : — " At the present time there are
only eleven apes on the rock, eight females
and three males. Of these onl\' three are
of the original Gibraltar stock. The
remainder ha%e been imported from \arious
parts of .Africa, and there are altogether
specimens of four distinct races. They have
not bred on the rock for years, but fresh stock
having been imported, it is hoped that there
will soon be some ' home-bred ' ones. The
first time I saw them there were six
together ; they were very shy, and my
repeated efforts to get photo.graphs failed."
.Afterwards Mr. Hony succeeded, and one
of his pictures is here reproduced.

Knowledge.

With which is incorporated Hardwicke's Science Gossip, and the Ilhistratcd Scientific Xews.

A Monthly Record of Science.

Conducted by Wilfred Mark Webb, F.L.S., and E. S. Grew, M.A.

DECEMr.i:K, 1911.

THE NEW ASTRONOMY.

IV.— THE GAL.AXV AND AN IMMORTAL C()SMO.S.

By PROFESSOR A. W. BICKEKTOX.

Thi^- more \\e study the stars, the more we are
impressed w ith the fact that the stellar s\stem is not
a chance distribution, but on the contrar}-. that
almost the entire content of the celestial \ault
that we can see, whether it be nebulae or stars,
is a single organized s}stem and has a definite
boundary.

Whiti.-. planetary and diffused nebulae ; star
clusters • temporarw variable and double stars, each
and all occup\' definite positions, every one of w hich
offers striking evidence of a s\'stem of evolution
as consistently simple as it is conclusively
demonstrated.

Taken roughly as a whole, the Galactic Universe
consists of a belt of stars, containing lateral streams,
dense aggregations in parts, and equally striking
defects of illumination in other parts. This rough
ring or belt is possibh' i>f a double spiral character :
this opinion is ver\' firmh' held b_\' Professor See and
a number of other able astronomers. This belt of
stars, which varies from some ten to twent}' degrees
in width, is almost exactly bisected by a great circle
of the heavens. Leaving the margins of this stellar
belt, we come upon two belts of the celestial sphere
that are sornewhat sparsely inhabited. Then, as we
ajjproach the two poles, we meet with an increasing
number of nebulae. These seem to have their
maximum density in both hemispheres in a position
approximately that of the poles of the great circle
of the Galax}'. (See Figure 1.) It is well to
hiok upon this great circle as the equatorial
plane of the Sidereal Universe. A vast number

of these nebulae are, as described in our last
article, of a double spiral character. The\-
are, as a rule, what are called White Nebulae,
that give continuous spectra, suggesting that
the\' are dust swarms. There are comparatively
few stars in the polar regions of the heavens.
Stars are mostlv confined to the equatorial belt,
and it is in this same belt that we find nearly
all the gaseous nebulae of the heavens. These \ast
masses of diffused gas are of two kinds, the one the
planetarv nebulae, already described. Usually,
although ver\- rare, these are extremely definite.
The other class of gaseous nebulae, such as
the great nebula in Orion (see Figure 4), is
of extreme irregularit\', usually quite devoid of
an\- s\"mmetr\- of form, vet exhibiting marked
structure that often seems to suggest drifting
motion. In this same Milk\' Way belt, in addition
to gaseous nebulae, are to be found most of the
beautiful star clusters. Nearly all the temporary
stars have blazed out in this belt, and it is in this
same belt that we find most of the variable, or
wonder stars, most of the telescopic double stars, and
spectroscopic binaries, and here also, although some-
what singularly situated, we find the Wolf-Rayet
stars. But very few White Nebulae are found in
the belt of the Milky Way. (See Figure 2.)

Indki'knoent Sii)i-:kiiAi. Systems.

In addition to all that has been described, that
seem to be parts of one consistent whole, we have
other s\-stems which it is not certain belong to our
Galactic Universe at all. It is the opinion of Sir

453

454

KNOWLEDGE.

December, 1911.

David Gill that the great nebula of Andromeda (see
Frontispiece) is a distant Sidereal system not unlike
the Galactic system. This opinion of Sir David Gill is
shared b\' other astronomers, who believe that in this
beautiful oval patch of light we are looking upon
an orderly system of millions of suns. I'roni the
brilliant centre it possesses it is probahh' in an
earlier stage of e\(ilution than is our own Sidereal
Universe.

The cxfjuisite photographs of the Magellanic
Clouds suggest that each of these twt) gigantic
systems is an independent double-spiral Sidereal
universe, for spread through each of them we
have star clusters, double, and wonder stars, just as
in the belt of the Milky Way. Their appearance
suggests that they are not much more distant than
some parts of the Milky Way itself. Hence. the\-
may at one time ha\'e been subsidiar\- parts of our
great Stellar system. The Pleiades also seem to be
somewhat independent in character, both from their
position as well as their appearance, as shown in
Figure S. There are other minor systems that
also suggest independence. Everv star in the
entire heavens seems to be mo\ing. The name
Proper Motion is given to this indei)endent travel
of the stars. It seems to have a mean value of
something less than twenty miles a second, but
some of the stars rise to speeds of some hundretis
of miles a second : " runawa\- stars " these are
sometimes called.

The motion of the stars is not indiscriminate :
most of the stars appear to be moving in two stateh'
jirocessions in opposite directions. The distances
they are apart are so enormous as to suggest that
they do not often collide, but impact is undoubtedh'
a law of nature, and a surprising number of agencies
have already been found that, in spite of the
enormous distance of the stars from one another,
must tend to produce impact. In addition to these
two stately streams a number of minor drifts occur.
This, then, is rouglily the character of our Sidereal
Universe. It will now be our task to attempt to
show the mode of its origin. I sjjeak of it as an
attempt, but it is more of the character of an induc-
tion that has been demonstrated to be true b\- the
fulfilment of endless anticipations based on
dynamical deductions. The able mathematician
Clifford says : " It has many of its predictions
verified by subsequent discoveries in a manner as
striking even as the fulfilment of the predictions
of Mendelieff, based on the periodic law."

The Oki(;in of thk Galactic Universk.

The character of the .Milky ^^■ay. as seen in the
Southern Hemisphere, is much more suggestive of
the mode of its origin than the portion we can see
here in England. .\ centrifugal tendency is most
strikingly exhibited. Lateral streamers seem to
travel away from the main drift, suggesting the
sprays of splashes left by a twirling mop.

It was in the Southern Hemisphere that,

probably for this reason, some thirt\-two years ago,
a study of a beautifully clear sky suggested that the
Milky Wa\- was the result of the whirling coa-
lescence of two previously existing independent
cosmic SN'stems. A careful stud\' of Proctor's book
on " The Universe " aided b}- Sidne\- Walter's
exquisitel}' coloured charts of the two hemispheres,
quickh- convinced me that the induction was right :
and every disco\-er\- made by astronomers since that
time has tended to strengthen the conviction, and
nothing more strikingly than the concluding remarks
of Professor Kapte\'n, before the Dutch Science
Congress, on the Cosmic Cycle, which are quoted in
the last section of this article.

The Dynamics of Coalescing Cosmic
Systems.

Let us try and imagine the dynamical conditions
that could bring about a configuration and distribu-
tion of material similar to the contrasted system
that forms the Galactic Universe.

Later on in this article, the mode of formation of
primordial cosmic systems will be described. It is
deduced that they must consist chieflN- of the lighter
elements, taken by the high kinetol of the atoms out
of cosmic systems. Through this ))rimordial matter
denser material is somewhat S[)arsel\- distributed.
We have already seen there is a continuous tendenc\'
during the whole existence of Sidereal s\stems for
light elements to be expelled. The many different
processes are debated in the article of the Septetnber
number of Harper's Mas^azijic. " On the Cycle of
the Eternal Hea\ens." The\' are also discussed in
some fulness in the " Birth of \\'orlds and S\-stems,"
Harper's Library of Living Thought. Hence
decadent cosmic systems tend tt) consist of com-
pact suns, chiefiy of heav\' elements. Many of these
bodies are dark stars, commonly known as dead
suns. Thus we have two classes of cosmic s}-stems,
the incipient ones, consisting chiefiy of light gas.
and the decadent, consisting largel)' of compact
masses of heavy elements.

Imagine two such systems to have come within the
sphere of one another's attractions. Lateral attrac-
tions would prevent the encounter being quite centre
to centre. Thus it is a case of whirling coalescence.
As the two svstems close in, the one upon the other,
an immense friction ensues. The mutual attraction
of the advancing suns, aided by this resistance,
would cause collisions: a vast central furnace would
thus grow up. The field of collision must for ages
have gone on increasing both in density and- dimen-
sions. The furnace is walled around by the advanc-
ing material in all directions in the plane of impact.
Presently, as temperature and density increase, the
pressure becomes enormous. This explosive matter
can find no relief in the plane of impact, for, as
alread\- shown, the material of the two \ast sj'stems
is crowding in all around it and walling it in. But
axially there is a chance of escape. The material is
ejected towards both poles, and this action goes on

December. 1911.

KNOWLEDGE.

455

increasing in intensit\' for ages, as the vast masses of
the two systems continue to crowd in upon one
another. In mj- earlv papier the name '"a.xial
extrusion" was sriven to this d\namical action.

as we have said, in the opinion of Sir David Gill,
is a system of similar order to our Milky Way.
^It should be understood that even in the case of
whirling; coalescence the central portion is the third

Figure 1.

The White Nebulae, largely double spiral, and Clusters in the Northern Hemisphere, plotted on eijual surface-projection

by Mr. Sidney Walters, from Sir John Herschel's catalogue. The Nebulae are represented by dots, the Star Clusters by

crosses. In this same belt are temporary, variable, double, and W'olf-Rayet stars. This belt is the MilUy Way. it contains

the bulk of ordinary stars. Identically the same general distribution exists in the Southern Hemisphere.

Presentl}" such an enormous quantit\' of material
has been expelled that the capturing i)ower of the
third bod\- diminishes. Selecti\e molecular escape
expels still more material, and the great central
furnace begins to burn itself out. This seems to be
the state of the great Nebula of Andromeda, which,

body formed b\- the twi) coalescing portions. It
possesses the thermodynamic intensit\', and possesses
also the capturing power. When axial extrusion
occurs it ma\' be pointed out that the capturing
power diminishes, as it does in the formation of
the orbits of a double star.

456

KNOWLEDGE.

December, 1911.

Presently the capturing power of the third body
lessens so much that the central attraction almost
ceases, and the walling-in material is now urged
forward by its own onward velocitx'. The onward
motion takes it away from the centre, and the great
furnace being no longer fed will soon have quite burnt
itself out. Notice that after pressure ceases to expel
material, atomic kinetol will continue to carr\' awav
molecules of low weiglit. This tangential motion
carries the material forward in the mode described in
the case of double spiral nebulae. The great Milk\-
Way thus gradually spreads itself to the vast dimen-
sions to which it has
attained. The dimen-
sions of cosmic s\stems
appear always to be of
enormous areas, and
consequently the great
central furnace would
[)robabi\- occupy but a
small ratio of the wiiole.
The two vast systems
would be proceeding
onward, in opposite
directions, outside of
the sphere of central
influence, and it is this
continued original mo-
tion that gives us the
two majestic streams of
stars whose existence
has been demonstrated
h\ a number of inde-
pendent workers.

It is probable that
ever\- bodv and system
in the universe possesses
more or less rotation,
and tile old cosmic
system that, b\- inter-
penetrating the pri-
mordial, went to the
making up of our N'irile
uni\erse, most probably
liad a rotation of its
ow n : this rotation
would continue even

— ]? -

■"-, ^ P-- ■• ■■$

sr*%,.

f:

.<h**

'Hpi ft.

during the impact, and

it is almost certainly a
continuance of this motion that is seen in those
great streams of stars that called my attention
to the probable origin of the Galactic Universe.
There is one verv definite principle of impact. It
is that all motion developed during the collision
tends to regularit}-, and all previously existing
motions tend to disturb this order.

Summary.

This, then, appears to be the motie of origin of the
Sidereal Universe. Two cosmic systems of \'ast
dimensions, one primordial and the other mature
or decaying, approached one another, draw n together

I'IGURE 2.

Diagram — oblique view — of the constitution of the Galactic-
System. It is made up of three parts: —

I. — A vast double spiral ring of stars. In tliis belt the dots repre-
sent the star clusters, the temporary, variable, double, and
Wolf-Rayet stars and planetary nebulae, these last being
gaseous. The vast irregular nebulae such as that of Orion
are also here.

II and III. — The two polar caps of the same System, mainly
composed of White Nebulae with, as a rule, continuous
spectra. These are largely double spirals, as shown in the
diagram -

bv mutual attraction. They obliqueh' interpene-
trated one another and produced a vast central
furnace, from which were expelled the extensive caps
of nebulae that now clothe the two polar regions of our
sidereal system. This axial extrusion, and selective
escape, caused the central furnace to burn itself out:
the released centrifugal force carried the walling-in
material, stars and so on, to x'ast distances in space,
and formed the Milky Way, In this Milky Way
the opposite procession of the two streams of stars,
aided by attraction and other agencies, caused
collisions of dead and \ivid suns, and these

collisions produced, as
already described, tem-
porar\\ variable, double,
and Wolf-Rayet stars,
planetar\- nebulae and
star clusters. The whole
of these bodies represent
the wreckage of col-
liding suns, and are all
found wherever stars
crowd and probablv
collide. Because these
impacts possess such a
wonderful buildin
power this theory
impact is sometimes
called " the principle of
constructive collision."

The above sketch
shows how remarkablv
the actual facts of the
order of distribution of
the Universe correspond
with the dvnamical de-
duction made so many
years ago. It must be
remembered that the
most strikinglv confirma-
torv facts are discoveries
made many years after
the deductions were
worked out. Some of
the more convincing
and sensational of these
will be better understood
when we have studied
the agencies that show-
agencies that
in founding his

b

of

.9}

the possibilities of an Immortal Cosmos

Lord Kelvin o\'erlooked when he

doctrine of dissipation of energy, looked upon this

principle of degradation and death as applicable to

the Cosmic Whole.

An Immortal Cosmos.
Dissipation of Energy.

On this Earth, and apparently in the Solar
system, there seems no possibility of perpetual
motion. Coal burns, steam is produced, electricity
is generated, cars travel, rooms are warmed, and
light appears. But as the outcome of it all. low

December. 1911.

KNOWLEDGE.

457

; oil! II phfltog

temperature heat is almost entirelythe final result. To
get enerj:;v out of heat, there must he what is called
a refrigerator, in order
that this fall of tem-
perature may partly be
converted into motion
of mass. This motion
of mass will do work,
and the work changes
the motion of mass into
motion of molecule, and
this into the vibration
of the trembling ether.
So again the volume of
the Sun diminishes and
the pressure is increased.
The fall of the molecules
towards the centre
makes them move faster
and so the general tem-
perature of the Sun is
increased. But vast
quantities of this aug-
mented heat are poured
out in a ceaseless flow of
radiation, some of which
falls upon the planets to
be radiated again into
space, but most of it
speeds outwards in all
directions in an apparent
prodigality of waste that
philosophically appears
to be surprising. It is
the general idea that
this falls partly upon
the dust of space and
is partly sent to almost
infinitely distant regions.
We get from all these
ideas Lord Kelvin's the-
ory of dissipated energy,
which the Germans call
"warm death."

Aggregation of
Matter.

On the other hand
matter tends to aggre-
gate. Suns are of all ages,
incipient, voung, mature,
aged, and dead. A pair of
dead suns in coming into
complete collision be-
come vivid again, and
their luminosity may last
a hundred million years,
but this period is a mere
breath in eternity. They
again die, and may again

all the matter of the Universe collected into one life-
less globe, and all the energy of the Universe dis-
persed into endless
space ? Such was the
opinion firmly held some
fifty years ago, and it
continued to be held for
fulh' a quarter of a
century. Then chinks
began to appear in the
walls of this dismal
dungeon of thought, and
a little light has entered.
Although official science
still refuses to use this
hopeful light, average
humanity never quite
entered the dungeon, and
many minds now stand
in tile full light of the
optimistic thought of a
scheme of creation, infi-
nite, eternal and flawless.

FlGUKl

Nebulae in the Pleiades. December Sth. ISSS.

Ycrkci Oh

hs

Two New Agencies.

We have to ask : Are
there agencies that in
addition to concentrating
matter, can distribute it :
in addition to degrading
energy, can elevate it.
Certainly there appear
to be such agencies.
The collisions of suns
can scarcely ever be di-
rectly centre to centre :
ever\' law of cosruic
motion tends to make
the orbits of colliding
suns into curves, and no
pair of bodies that are
moving in independent
orbits can possibly col-
lide directly centre to
centre. Hence oblique
impact must be the cos-
mic law. These grazing
iiu pacts have already
been show n to take place
with such stupendous
s[)eed that the partial
impact cannot stop the
stars. A third body is
produced. If the graze
be of a small ratio, this
third body w ill form an
independent star of such
supreme power, so stu-
pendously hot, as to he
another collision, thermodynamically unstable, and to blow- itself to

FiGl'KE 4.

Great Nebula in Orion.

October iQi'i^ icol.

Is this rollinii up to go on until the entire contents isolated atoms. When the temperature of the mass
of the great celestial vault is one huge dead cinder ? becomes approximately uniform the kmetol of the

158

KNOWLEDGE.

December. 1911.

light elements becomes so excessi\'e. thnt they escape
not mereh" the new star, but the intluence of the
three stars. A high-velocit\' atom escapes the \ery
cosmic system of \\hich it is a part, and \\anders away
to the empty parts of space. .\11 the while it is doing
work against the gravitation of the cosmic s\'stem it is
escaping from, and it will linger in the [)ortions of
space \\ here there is a minimum of matter. Thus is
matter distributed. Sometimes again three stars
a(jproach one another and in the manner described in
'■ The Birth of Worlds and Systems "" one of the
three mav acquire a speed of sufficient power tn
project it bevond the limits of the cosmic system of
which it is a member. There are other agencies by
which material is carried out of systems, so that the
process of rolling up of suns into bigger and bigger
suns is not the onlv mode of the mechanism of the
universe. Just as we saw that impact is not a
random, chance, or accidental occurrence, but a
definite law of nature, do not these distributing
agencies show that there is a law tending to a con-
stant rough equalit\- in the distribution of matter?

Elevation of Degr.vded Energy.
It is now our task to ascertain if any law exists
b\- which the degraded energy that we call low
temperature heat, can be raised into that highest
form of energv which is known as the potential
energ\- of separated gravitational masses. What
becomes of this torrent of vibrator\- energy that is
pouring out from the hundred million suns of our
s\'stem ? It probably travels to enormous distances :
it is exceedingh' likely that it will ultimately fall on
the dust of space and waiin it, and, if there were no
other agencies, give us the condition that Kel\-in
deduced, and the Germans named " warm deatli."
But another exceedingly complex series of factors
must apparently be brought into play. Bodies,
whether dense masses or isolated light atoms, w hen
not entrapped into orbits must occupy but very
little time at high velocit\-. As the speed grows less
the duration grows greater, until when nearly at rest
they must occupy durations that are almost
immeasurable. Xow a particle of gas at rest is at
absolute ^ero. So that much of the free molecular
matter of space must be very cold, as it is moving
slowly. A slowly moving particle of helium or
hydrogen coming in contact with a warm particle of
cosmic dust will acquire its temperature, and this heat
will become 'molecular motion, and the molecule ^^■ill
leave the particle with an increased velocitv. This
increased velocit\' will cause it to travel away, often in
the direction that will convert its atomic motion into
potential energv of gravitation. Coming nearly to
rest again the process will be repeated, until, as a
final result, the molecule will wander until it reaches
the position of high potential in space, where it will
necessarily linger longer than anywhere else.

Another Aggreg.^tinc, A(;ency besides

Gravitation.
In a position where bodies moving indiscriminately
linger longest, there they tend to accumulate. In

1.S79, when this principle was first detected, it was
called the .Aggregating Power of the Position of High
Potential. This principle, which no mathematician
has e\-er disputed, and which one of our ablest has
called "a mathematical vera causa." shows us that
we have a second aggregating tendency in nature
in addition to gravitation. Do we not again perceive
another law of nature tending to elevate degraded
energ\- so that it shall be jierpetually available for
the purposes of life eternal ? Do not these three
laws of nature, added to our former knowledge,
show us a cosmos infinite and deathless ? First we
have the set of agencies that produces the construc-
ti\e impact of cosmic bodies and S}"stems ; then the
one that tends to distribute as well as aggregate
matter: and, lastly, this complex series of agencies,
made up of the high kinetol of light atoms, the eleva-
tion of degraded energy, and the aggregating power of
the position, of high potential. The whole gives us
a series of wonderful laws of nature that, together,
present us with the possibilities of an immortal
cosmos of infinite extension and perfection of design.

Till-: Tni:oKY a Demonstrated Deduction.

I-'inallv comes the question : Is this beautiful
optimistic picture of the Cosmic scheme a true one?
Grant grazing impact and, as Sir David Gill has
stated, the idea of the formation of the third body is
true. \\'hen we consider the dozen agencies that
tend to produce impact we cannot doubt its happen-
ing. Even did we, without e\'idence, doubt, when we
consider the coincidence between deduction and
observation e\'er\' trace of doubt absolutely dis-
appears. It is (juite certain that Nova Persei was
the third bod\- produced by the graze of suns.
Every thermod^namical, chemical and physical
deduction made thirt\'-tliree years ago, has been
confirmed. Sudden apjiearance. rapid increase in
brillianc\", (]uick disappearance, all agree. Everj^
character of the abnormal light curve agrees. Every
one of the series of complex spectra tells the tale
of the ph\-sical changes of nucleus and ensphering
shells in exquisite minuteness of corresponding
detail. The star, as was deduced, passed into the
planetary nebula stage. .\ny one of these striking
confirmations, in the al)sence of opposing evidence,
would suffice for a demonstration. \Miat shall we
say when we tliink of the fact that the several
different series all correspond in each and in every
step ?

Novae Demonstrated to be Third Bodies.

Hence, emphaticall}-. Nova Persei was a third
body, and as all novae arc so typicall)- alike in
their man\' characteristics, we must infer that all
novae are the exploding third bodies struck from
grazing suns.

Then take the mass of evidence that variable and
double stars are the torn suns, and again how over-
whelming is the evidence. Ever}- deduced salient
liliysical feature has a representative in fact, often
m a multiplicit)- of confirming facts. Why should

December, igil.

KNOWLEDGE.

459

\ariahles be in pairs ? \\'h\- siiould binaries be
variable and often doubh" variable ? In each case
the probabilitv against chance runs into sextillions.
\\'h\- are thev associated with nebulae ? Consider
again the form and character of nebulae. Why
should the spirals be always double ? Why are the
planetar\- nebulae often sphere in sphere and hav-e
centres e.xactK- as deduced? Why should double spiral
nebulae be amongst nebulae where stars are scarce,
save that, as deduced. the\' are formed b\- the
impact of nebulae ? Wh\- should the planetar\-
nebulae be where the stars are thick, clearly because,
as deduced. the\' are produced bv the impact of
stars? .Are not the temporary variable, double, and
Wolf- Ra vet stars also where stars are thick ? Is not
the answer obvious, because, \shere stars are thick,
there will be a maximum of stellar collisions, and all
these kind of stars are deduced as the offspring of
stellar collisions.

The Drvr. Character of The CiAi.axv
Demonstr.\ted.

Then, when we come to the Galax\-. what other
conception is possible that could produce such a
marvellous and singular set of contrasts and
correspondences, but the impact of two formerh-
independent stellar s\stems? Here Professor
Kapteyn's demonstrations are all-important. He
concludes his magnificent address to the Dutch

.Science Congress in the following words: — "The
stellar system was not originally a single system
in which the two known drifts or currents have
developed: but the present system is the result of
the encounter of two systems wliich originally were
entirelv independent of each other.

The primordial matter is now more abundant in
the drift of less star-density, and is almost entirely
absent from the opposite drift, which is richer in
stars."

Clearly in this primordial material we have the
cosmic system of the first order that a study of
natural law has shown must grow up in the
unoccupied parts of space, and the other constituent
is clearh- a stellar system of greater maturitv.

Surely such a fertile generalization should be used
as a working hypothesis to guide research, and that
at once. If it is true as able thinkers sav that
the neglect to use it in the past has retarded
astronom\- a decade, all haste should be made that
the several threads suggested should be followed
and woven into a fabric in which ever\- thread
has its allotted place and ]iurpose : so that this
glorious science, astronomy, instead of being a
mere chaos of facts, instead of apparenth' pointing
to eternal death, shall show itself to be a consist-
ent system of creation without evidence of a begin-
ning or promise of an end. infinite and flawless.

0\^CR^M OF COSMIC EVOLUTION

APPPnOftCH of BODIES '

THfvxc BOD1C9 . onerrs iNorrsRMiMhTE

l»*enC*5E0 SOMCTIMES 5wfriti(MTi.» TO ESCAPE

OOltS

TtMO OOOICS IMPACT

D»n«CT

bSMG*

nM*i

••»

o <;••

V

T>V3» Imtialls offu" ■'\U«jlvfui

CeAji rtu^\*(uUl UocK tWi^ iiuo< (OEQ

CINTlOtl. OOJtLtKtO VttA^

I

Sf/.

'/iXi

/vaOt^tAM

RCCtON or H(CV* POTKMTIAC

rOKMJUTIOM or COSWIC SV^EMS
Of TH«

FtHST ORDLR

Sit SeUtUw M(4.ttUrEflt4)t'l*iJ"tr4. vnaU.
Imports t«nJi/ig U KR."rt t^J HJOJtJ

b«u\^ (n tKt lutduU MfcfUn tflta^'iny
oltcijttlier.

Figure 5.
Diagram taken from Professor Bickerton's "' Romance of the Heavens."

19{)().

Kapteyn, by summing up bis own theory, Greenwich and others' observation, has now satisfied himself that our Galactic Universe is
made up of two interpenetrating systems, one of them primordial, that is of the first order, as shown to be forming below the

centre of the diagram.

■ii.rKi-: 1.

The Cameras and methods of illumination.

THE PROCESS BLOCK.

Bv H. E. RE A.

Process blocks are tised now for pn
trations in all sorts of periodicals — in tl
newspaper, as well as in
the finest hook or art
catalogue.

A block must he made
capable of printing side
h\' side with type, and
it must he able to gi\'e
all the range of tones
of the original from black
to \\ hite. It is made to
do this h\- having its
surface cut up into a
very large number of
"dots" or squares — so
small as to he, as a
general rule, unnoticed
hv the naked eye — which
catch the ink when the
roller goes over them
and which immediately
afterwards print the
picture.

The block-maker has
first to consider — when
he gets the photograph
or drawing which is to
be reproduced — what
sort of jiaper the block
whether rough or with

nting illus-
ialfpenn\'

art paper.

is the nimilxr

Th

i^i*

FlGlKI. 2. '1 he LauiLia witli tlie screen ni (m.^uinn

is to be
smooth

used upon,
surface, or

better the paper is, the greater
"dots" which can be made and
the closer they will be
together. The original
is then pinned up on
the cop\ing - board (see
Figure 1), which is illu-
minated by two power-
ful arc lamps, and a
photograph is taken of
it. which may reduce
or enlarge it. according
to the size of the block
wanted, and which, at
the same time, brings
the " dots " into exist-
ence. This photograph
may be taken by means
of the wet collodion
process, the collodion
enudsion process or on
a dry plate. In the first
twd cases the operator
^ has to prepare his own

.-tV^^ j plates, but dry plates made
iL XjJ^jjrr especially for process-
■^^ ^^^ ■ workers can be obtained
from the dealers. The
writer uses dry plates.
The " dots " are obtained by interposing in the
camera, between the photographic plate and the lens,

460

December. 1911.

KNOWLEDGE.

461

Figure 3.
One h.ilf of tho !;creen.

Fir.i'RE 4. The dots enlartred from a .screen negative.

FiGLKL. 5.

If this pictnrc is held at a distance from the eye the eftect of the The cross lines of the screen,
photosjraph will be seen. It is part of Fit;ure 10.

a ruled screen (see Figure 2), which is made by gets cut uj) into a series of dots and squares

having two diagonall\-ruled glass plates sealed — ranging gradualK- from fine black dots in the

together — the result being a cross-lined mesh transparent parts of the negative to squares in

(see Figure 5). The image passing through this the half-tones and transparent dots in the high

FiGi l^l I'. Printing.

FlGL'RE /. Firing the Pl.ite.

AC2

KNOWLEDGE.

Df.cembf.r, 1911.

lights. The mesh of the screens
ranging from fifty hnes to tiie
heavy or rough printing
to four hundred Hnes
to the inch for the
most careful and finest
art printing. T li e
most useful screens
have one hundred and
twenty, one hundred
and thirt\-three and
one hundred and fift\-
lines to the inch, and
these are, as a general
rule, the sizes used in
connection with illus-
trations for magazines.
In the case of the
dailv papers — which
are very rapidly
printed on fast-running
machines — the illus-
trations require screens
with a much more
open mesh — usually of
from seventv - five to
one hundred lines to
the inch. If t h e
reader will examine
one of the illustrations

\aries much —
inch for \'er\'

requn-ed distance from
kind of ■■ dot " desired-

I'lGL'Ki; ,s. The Etching K.ith.
Examining the plate for depth.

the plate — so as to gi\'e the
die makes his first exposure,
which is to give the
■■ dot " formation in
the darker parts of
the subject. He then
places the cap on the
lens, puts in a larger
stop and exposes again.
He, in this wa\', gets
a " dot "' formation of
the detail. The third
exposure — with a still
larger stop — is for the
"dot" formation in
the high lights (see
enlarged illustration of
the screen effect in
Figure 4). Some
operators make only
two exposures. The
different stops used vary
a great deal. Some
operatxirs favour one
kind — others another.
The writer uses three
kinds — a verv small one
to gi\e the "dots"' in the
blacks, one about three
times as big to give the

ElGURE 9. A Fine Etcher at Work.
"stopping out.''

^'E?

]

^HP^^^x-«^i!^i^^4^»v^^^H

fl

^^^^^^^^^w/

WilP^^^^^J

1

B

En, LKi. 10. EngruN iiig the Plate.
■' Taliing out blemishes."

in this magazine under a strong magnifying glass detail, and a square one, about three times the size

he will see how the picture is formed by the " dots " of the one last mentioned, for the high lights.

and squares. The exposures are \ery short — whichever of these

When the operator has adjusted the screen to the stops are used. Their w hole aggregate length — from

Ill ( IMl'.l K. I'Ml.

KNOWLEDGE.

463

the beginning of the first till the end of the third —
varies from a minute and a half to three minutes if
an arc lamp of the enclosed t\"pe is used, as this
gives the greater percentage of violet or acti\-e ravs
of light, to which the plates are most sensitive.
The exposure with the o|5en type of arc lamp is
about three times as long

The exposed plate is now dexelojicd in the
ordinar\- waw and it is afterwards reduced (in
densit\), or, to use a trade term, "cut in." b\- letting
a solution \\hich diminishes the size of the "dots"
flow over it. This is done until the "dots" are of
the size necessar\' to gi\c the reipiisite brightness.

The object of the burning or baking is to make the
coating into a hard enamel.

The plate is now passed on to the etchers, who
place it in a solution of perchloride of iron. This
eats awa}' the copper between the dots, and thus
leaves the image standing up in relief, the enamel
not allowing the solution to touch the "dots." A
rough jiroof is now taken of the print in order to see
what further etching is required. This fine etching
(see Figure 9) is done b^• stoi)ping out, with a resist-
ing varnish, parts which do not require an\' further
etching, and the high lights are then etched up
so as to give more brightness and detail.

I'lL.liKi; 11. Routing away useless metal.

By using the two handles the router can be made to go in
any direction desired.

iMi.uui; 12

In this way it is

when it w

Lining and bevelling the plate,
ot ready for nailing on to the wood

be type-high.

The finished negative is now dried and given to
the printer. After he has examined it to see how
long it will take to print, he places it in contact
with a piece of copper, which has been made sensi-
tive to light — both being put into a printing frame,
which enables great pressure to be exerted to bring
the two close together. The piece of copper is
sensitized with a solution, composed of white of egg,
fish glue and bichromate of ammonium. The
frame is put in front of a strong light, which, acting
on the sensitized copper through the transparent
parts of the negative, prints the image on to it.
The print on the copper plate is then developed in
water, which dissolves away the solution not acted
upon bv the light, and it is afterwards burnt in
over a Bunsen burner (see Figure 7). The result is
a print rnade up of a series of " dots " and squares,
ranging from fine white '" dots" in the blacks to fine
black " dots " in the lightest parts of the subject.

When the etchers have done all that is necessary
the plate is then passed on to the engravers (see
Figure 10), who take out unnecessary spots and
engrave up what lights require brightening or what
darks require a little burnishing so as to give a
greater depth of colour.

The block — as it ma\' n(.)w be called — is now ready
for the finished proof to he taken, and after that is
done it is given to the mounter, who fastens it on to
wood of such a depth as to make it as high as type.
It can now be printed side by side with type.

The methods of working and the apparatus used
have, within the last few years, been brought to
such perfection that it is now possible for a block to
be completely made — ready to be put on the printing
press — within one hour from the time the photograph
or drawing is placed in the operator's hands. This,
of course, is onl\' for a hurried illustration ; the usual
time taken over a block is from four to five hours.

A SCANDINAX'IAN TRIBE IN THE ARCTIC

NORTH-WEST.

Bv COMYNS BEAUMONT.

The "new" race of Arctic men which Herr
\'illijmar Stefanssen, the leader of the American
Museums' Scientific Expedition, has discovered in
the Arctic regions north of British Columbia,
provides an in\ahiable link in the cliain of evi-
dence which the advanced school of ethnologv is
forging.

Herr Stefanssen is astonished to find that this
race of men are Scandinavian in appearance.
Evervone asks how can it be ? Students of Polar
research, at a loss to interpret the plienomenon,
wonderingly suggest that the men arc descendants
of the crews in Sir John Franklin's expedition, who
had inter-married \\ith the Eskimos. If this were
so. in such a comparativeh' short period these men
would be able to make their identit\- clear. In less
than one hundred years men belonging to a virile
race do not lose their language, their customs, or
forget the fatherland. Indeed, it requires immense
periods for colonisers or emigrants to change their
language, to forget their national customs and to
allow their earlier histor\' to pass into iu\th or
legend.

Stefanssen as yet has gi\'en us few particulars
respecting these Polar Scandinavians, excepting that
two of the men had red beards and that the\' were
markedly European in type.

If the descri[)tion. meagre though it be. prov-es
correct, they should be a remnant cut ofi from the
great Scythian famil)-. and as such can have no
relationship whatsoever with the Eskimo, w ho belong
to the same family as the African Bushmen.

Who were the Scx'thians ? What limit ma\- be
imposed on their ramifications ? If these two
questions may be answered, a solution will [irobabh'
be found to the myster_v of Scandinaxian t\-[)es in
the Arctic north-west. The Sc\-thians were people
of fair complexion, blue or light eyes, with flaxen
brown or red hair and of strong physical build.
From the remotest times they descended from the
north, a people possessing a restless unconquered
spirit, apt to take fire at the ver\- mention of
subjection and restraint, and overrunning the globe
in more than one continent. The Scandinavians, or
Goths, were Scythians.

There is no vaguer term in ancient geograjiln"
than Scythia. Blackwell, the editor of ^lallet's
" Northern .\ntiquities," says that it would embrace
all the countries lying between the river Don in the
west, the great desert of Gobi in the east, the
Hindoo Koosh mountains in the south, and the

plains of Silieria in the north. " in wliich direction
the boundaries might be limited or extended to suit
an\' particular theory, being for the ancients terni
incof^nita." But the original name of the Scythians
extended over a much wider field than Blackwell
considers adequate. We find undoubted Sc\thian
traces in .America. Maj(_)r P. H. Fawcett. F.R.G.S.,
has collected evidence, hard to dispel, of a race of
white people with red hair in the liinterland of
Brazil. Short, in his " North .\mericans of
Antiquit\-," confesses that the standing pu/zle to
ethnologists is the wide range of colour and com-
plexion found among the American Indians. The
Menominee. Dakota. Mandan, Allegheni and Zuni
tribes, among others. ver\- often possess auburn hair,
blue eyes and white skins. W'ho were the famous
Chichimecs of American legendrv ? The Chichimecs
entered Mexico from the north : they came from
■' Ainaquemecan," a " land of vast extent " : their
titular deit\' was \'otan, or Odon, whom the erudite
Humlioldt was astonished to find corresponded in
ever\' [larticular with the Wodan. or Odin, of the
Sc\'thian nations: this \'otan (also called Odin, or
Oton) was a white man, with a long beard, attired
in white garments bearing the insignia of the Cross
in red. The ancient and mvthical capital of this
people preserved in records like the Popol \'uh. was
a city called Tula, Tulan or Tulla. The Popol V'uh
tells us that Tida was bitterh" cold ; for instance.
Part III. Cliap. \". \erse 5, says: ■" I'Ut then began
a great rain that extinguished the fire of the tribes
and much snow fell on the head of all the tribes and
their fire was extinguished then because of the snow ;
there was no more of this fire which had been made."
And verse S : " And they were able to do nothing
because of the cold and of the ice. trembling (as they
were all) and chattering their teeth the one against
the other, having no more life in them, feet and
hands benumbed, to the point that they could no
longer hold anything." It must be remembered
that tile Popol \'uh is the ec]ui\-alent of the
Pentateuch among the Ouiche peo[)le, who were,
like the Hebrews, wanderers for long periods over
large extents of territory, and who, like them, were
enslaved h\ a Pharaoh through whose country they
passed. The people who enslaved them were the
Chichimecs. .\nother deity of the Chichimecs was
Toras, whose name and character closely resemble
the Scandina\'ian Thor.

-At a comparatively recent date, even as records go
(opposed to legend), there is no doubt that the

464

December, 1911.

KNOWLEDGE.

465

nortlierii portions of the world were inucli more
closeh- linked together than is the case to-day, and
that the ad\-enturous peoples from the northern parts
of Europe were not uncommonly accustomed to make
voyages to Greenland and Northern .\merica, owing
to an almost continuous land connection. In the
Icelandic sagas, that part of .\merica embracing
Texas, Florida, the valley of the Mississippi, Georgia
and the Carolinas was designated under the name of
Ire]and-ik-Mikla,or Great Ireland, and was considered
to be a land of white men. (See Beauvais," Decouvertes
des Scandinaves en Amerique.'")

We have, then, undoubted traces of Teutonic,
or Scythian, descent in America ; the same race
over-ran the north of Asia and Europe : tucked
awa\- in a corner of the Arctic regions is a
small tribe of apparent Teutonic characteristics.
Were the Sc\'thian peoples always unsettled, always
wanderers over the north, or is there some truth
in the Chichimec legend that they inhabited
Amaquemecan. ■■ a land of vast extent'"?

\\'hat does the geolog\' of the Arctic regions teach
us ?

There was a period when lands stretching across
the Atlantic Ocean, and which linked up the Atlas
range with the West Indies and Central America,
were gradually breaking up. At this time the United
States proper did not exist : its place was occupied
b\' a brackish sea containing a number of islands:
but in the northern portions of the Atlantic region
definite evidence exists of the presence of dry land,
while a good deal of modern Europe, North America
and Asia were occupied by the ocean bed. Certain
flora of the Tertiary period, co\'ered b}- basalt, occur
in Count\' .Antrim ; the same flora — Taxodiiini
ciisfichiiin — has left deposits in lignite in Spitzbergen,
Ireland, the Hebrides, the Faroe Islands, Iceland,
Greenland, and even beyond : Fieiden found Tertiary
plants in British Columbia containing examples
belonging to Mexico and the South, and the existence
of this flora, says Professor Suess, " has been fre-
quently regarded as a proof of the existence of a
great continent, richh- covered -with vegetation,
which occupied the site of the [iresent North
Atlantic Ocean. "*^

Elsewhere^ in his magnificent work, Suess points
out that the Tertiary land faunas of North America
correspond ^\■ith those of Europe, demonstrating
clearly that a once wast northern area definitelj'
connected, has been broken up, of which parts dis-
appeared. This reconstruction of lost Hyperborean
lands is, curiously enough, borne out b\- the celebrated
map of America added to the edition of Ptolemy's
Geography, which showed not onh- Greenland and
Newfoundland, but separated the north entireh- fnjm
the i\merican Continent, and carried this northern
land across until it united with the north of Asia.

The Greeks and Romans preserved lively recollec-
tions in their mythology of this great Hyperborean
Continent, situate far to the north-west, and which

enjoyed a mild and beneficent climate. It was the
Saturnian Continent, where Saturn, Hercules and
Apollo were honoured. Thence Hercules led an
expedition whose first destination was to such a
northerly clime that, according to Plutarch, during
thirty days the sun set for only one hour, and even
during that time a twilight reigned. Ogygia was
distant further still, where Saturn slept in a deep
cave where he had been placed by Jupiter. Indeed,
the trend of opinion to-da}" is gradually coming round
to believe that the Hellenes themselves originated in
this part of the world, and that their heroic stories
refer to that early period of flux when the Scythian
peoples lived in the regions now given over to the
iceberg.

Without question there was a period, not geo-
logicallv far removed from our time, when the Polar
regions rejoiced in a soft and beautiful climate. It
used to be said that this was before man lived. Now ,
on the contrary, the weight of evidence indicates that
man not only lived then, but that the north, as said
the Goth Jornandes, ^\■as the forge of mankind.
\Mien the north enjo\'ed a beneficent climate, prior
to events of the utmost magnitude which changed
the entire climate of the world and altered the face
of the earth, we cannot surely escape from the con-
viction that all the evidence is in favour of its being
the original home of a great portion of the human
race. We know that the earth has constantly
shifted its axis, and by a study of the other planets
we are enabled to foretell with some exactitude the
result of any great change. The causes which lead
to a shifting of the earth's axis need not be discussed
here, but the effects must be considered. According
to the esoteric belief of the ancients, including Plato,
the planet |upiter caused a world conflagration, and
whether it did so or not, there is no question but that,
prior to the Glacial Period, certain lands became
submerged, w hich interfered with its equilibrium and
caused the earth to shift its axis,owingto the change in

its centre of gravit>

"As the centre of gravity of the
earth varied," said Major-General Drayson, F.R.A.S.,
in a paper read to the Ro\al .\stronomical Society
in 1896. " due to the elevation and depression of
lands and the consequent transferal of hundreds of
millions of tons of ocean water so must the centre of
gravity of the earth have varied, and consequently
the angle formed between the poles of daily and
second rotation, and hence the climatic changes. . ."
The Glacial .\ge drove the Hyperboreans south.

be

an

Thus

among

small portion

which

that period of enormous migrations
the Israelites comprised but one
Millions of people perished, and
hence the universal Flood Stor}-. But. as though
it were b\- chance, here and there communities
were isolated and spared. Some of these in
turn sought more friendly climes, but others
remained : and thus we have a rational and natural
explanation of Herr Stefanssen's Scandinavian

tribe in

Face of the Eartli," Vol. 1. ]
t Vol. I., p. U.

the .\rctic regions of the north - west.

466

KNO\VLi:i)GE.

DlXHMBEK. 1011

k

J

cu^

MjU T^paJo ^ ,/^'/uWi/'>/(/M Cv 7^/iW /^/irjelAnf- JuMapaj /^tfc^ /^7tJ o^ ^4//^^ jir/^^cA) <r«/tL^
rtuPt^rmJ )<i40^nl- /thai-U B ■ cjUJ aZ-^^o ^^ citC^ c^V ^mV J'aC^ /^ ^/mu/u> Jc^^i^at-^

Tht-' above reproduction of a manuscript note is of interest m connection \Mtli onr article on the occurrence of Cliiroccplialiis
cliaplianKS in "Knowledgk" (Volume XWlll. page 169). The pas,'e was discovered among a series of coloured dra\vin{,'s of
Natural History objects, in the possession of Mr. Alexander Gordon, which apparently once belr)nged to Edward King. F.K S..
the Recorder of King's Lynn, whose father lived at Norwich Edward King wrote chiefly on archaeology and religion, but also took
some interest m natural liistory In liie orignial. which is reprinhiced liv Uind permission of Mr. Gordon, the lines are ui red ink.

PLANT HAIRS

r.v K. E. STVAX.

{Continued front I'agc /JO).

Part \I. — un Haikv Awxs and (/?) Pappuses.

Ix the threat work of dissemination of fruits and
seeds which is being carried on hv \arioiis agencies,

^^ - dail\', over the length and
breadth of the world,
hairy outgro\\ths play
a very important part :
for they ensure the
structures on which thev spring
being wind-wafted, whether or
no the\" take the form of true
coverings to the seed, "pappuses,"
or feather\-, silkv aw ns. or append-
ages. Usualh' the hairs found on
seeds and fruits are extremely
numerous, so numerous that it is
3^- quite out of the question to attempt

to count them, but instances do
occur in which onl\- quite a
limited number are present, of
which one good example may be
seen in the case of a plant called
Aeschynanthiis, whose fruit onl\-
bears three hairs on it. one on one
side and two on the other. But
these three are specially adapted
for the great use to which the\'
are called into being h\ being
remarkably flexible, which not
only causes them easily to adhere
to, but also to curl round the wool
or fur of animals after they ha\e
been wafted bv the ^\ind on to
the creature's body. Thus the
hairs in this case cause the fruits
to be disseminated both b\- wind
agenc\" and animal conveyance.
Exquisitely beautiful are manv

FiGL-RE 1.

Awned acheiic of

Sfripii pciinata

(two-thirds natural

size).

of the hairy prolongations that are found. Our

hedgerows in autumn are made charming b\- the

presence of silvery clusters of wild

clematis (see Figure 2), which is —

most truh- — a Traveller's Joy.

Each tiny part of one of these

clusters consists of a tinv fruit,

called an achene, bearing a verw

\ery slender, silky, hair\- appendage,

which is so light that the slightest

puff of wind catching it when the

fruit is ripe, enables the latter to
be wafted away through the air
like a bit of gossamer. Another
lovely example mav be seen in the
i^vass Stripa pen iiata (see Figure 1),
one that is often grown in gardens
for decorative purposes. The fruit
of this plant is an elongated, very
sharp. needle - pointed achene,
cox'ered with short, soft, silk\- hairs,
which are reflexed : from its upper
end s[>rings a slender, string-like
stem that becomes cork-screwed for
part of its length and then straight :
above this portion rises a verv long
(often more than a foot in length)
delicate hair\' awn. In its own
nati\e haunts abroad these awns

Figure 2.

.\wned achene of

Traveller's Joy.

Clematis vitalba

(life size).

Figure 3.

Awned achene of

Water .A v e n s ,

Gcitni paliistris

(enlarged).

Figure 4.

Tip of liaiiy awn of Geutn pcilnstris
(greatly enlarged).

Figure 5.

Base of the hairy awn of Gciiin piilitsfris
(greatly enlarged).

467

46S

KXcnVLEDGE.

Decembek, 1911.

FiGURl. 6.

Pilose sfssiic

pappus of

Roush Haukhit

catch the wind and bear the fruits miles and miles
over dr_\-, bare land, till some dam[)er spot is
reached, when, surrounded bv herbage, which arrests
the progress of the awn. and hv the unwinding
of tile corkscrew owing to the
moisture, the achene is forced into
the ground hx its sharp point and
there produces a new plant. The
Water Avens (Gciim paltistris)
(see Figure 3) produces an awned
fruit something lilsc that lA the
Tra\eller"s Joy. and the accom-
panying illust rat ions
(Figures 4 and 5) show
a series of magnified parts
of the aw n. The tip is slightly swollen anil
Sticky, and along the sides, amidst the long.
slender hairs, are some that are glandular.
The stickiness of these may be another
means b\- which the awn, after being
carried by the wind, can adhere to any
foreign body witli \\hich it ma\' come
into contact.

What are known as " pajjpuses "' are
the structures formed as " after-growths "
from the calices of many plant-species as soon as
the blossoms die and their fruits begin to ripen for
dissemination. So light are they. e\en if stemmed,
that the wind can carry them great distances:
the faintest puff, and awa_\- flies the fair\- " clock "
or ball of siKer "down," oyer meadow and hedge,
away — far away — till it gets beyond our sight :
or we may see the wind drifting (i\er countless
myriads of pappuses on some area of bog-land

long, slender white hairs encasing one tin\' fruit.
Then, upon the Black Poplar tree, in earl\-
summer, or on the ground beneath it. we ma\- see
hairy catkins that look just like tiny lambs' tails.
In reality these "tails" are onl\ aggregations of
satiny pappuses, each attached to a small seed.

Of all the natural orders, the Compositae show-
most pappus heads, indeed they abound in the
species of b'ilago. Cud-weed, (iroundsel. Hawk's-
beard, Ragwort. Hawkweed, Hawkbit, Cornflower,
Knapweed, Fleabane, Colt's-foot. Dandelion, and
Goat"s-beard. Figure 6 shows one separate pappus
from Rough Hawkbit. This has the
hairs springing from the achene icifliDuf

and Its

pilose."

Fioc
I'iii muse
pappus of

Haul,

KK /.

sessile
Mouse-ear
\\ eed.

where the Cotton Sedge grows

ni ra

id< I

iixunance.

swaying the snow-white hairy heads till the\-
look like breaking wayelets. gleaming as the\'
catch tile glint of passing sunbeams. In this
plant each [)appus consists of a tuft of soft.

a stalk (hence is called sessile)

slender hairs are unbranchcd. or

In the Mouse - ear

Hawkweed (see

I'igure 7) the hairs

are branched, or

" plumose " as the

botanical term is :

and ill Dandelion

(iMgure S) the}' are

imbranched but haye
a- stem, and hence are said to
be pilose, "stipitate."

The largest and most beauti-
ful of all English pappuses is
that borne by the Goat's-Beard,
one of the Compositae. in
which each separate fruit has a
mass of webbeti hairs at the
to[) of a long slender stalk,
forming a miniature parachute;

and the massing together of the many huits into
one head forms a large, silyery, hair_\- ball, that is
one of the most exquisite structures one can ever
wish to stutl\- in all the wide held of wild nature.

IlGL'KE 8.

bse stipitate pappus
of tile Daiulcliiiu.

-AIKTHORIC .SiioWl'R OF SEPTHMBHR 30x11.
Bv W. F. DENXIN'G, F.R..\.S.

Ix the October number of "' Knowledge," I gave some
particulars of several fine meteors witnessed on September 2nd.
There occurred a somewhat similar display on September JOth.

The nitjht was beautifully clear, and oflered an unusual
exhibition of cometary as well as meteoric phenomena, for no
less than three comets were visible to the nalied eye — two in the
evening, and one in the morning just before sunrise.

I watched for meteors for about one-and-a-half hours before
midnight and saw sixteen, of which four were fairly conspicuous.
Mr. Sidney Wilson and Mrs. FiaininettaWilson.of Bexley Heath,
saw thirteen meteors, and three of these were seen at Bristol.

.\ fireball brighter than Venus appeared at about 9.5, and it
was observed by Mr. H. Corder, at Bridgwater. He says it
gave a rather bright flash as it fell towards the western hori/^on,
and disappeared behind the Ouantock Hills. He only caught
about 6'" of the terminating portion of the flight, which was
directed from a Herculis from about 5° above fl Cygni.

The same (bluish-white) meteor was noticed by Mr. Joseph
MacDermott. of Glasnevin, Dublin, who describes it as of
twice the brightness of Jupiter as seen with the naked eye. Its
observed position was a little S. of S.W'., and it fell from about
30' to 15° of altitude in a direction from Pegasus.

.\ bright meteor was noticed by Miss Irene Warner, of
Bristol, at 10.5, falling from about 28° + 35° to 14° + 15° and
leaving a long red streak.

.At 10.40, Mr. H. Denning saw a fireball descending in
X. by W. He could not, however, exactly locate the
place of the phenomenon as he saw it from Stokes Croft,
Bristol, where there is a good deal of artificial illumination
and obstruction by buildings.

.\t 11 o'clock Mrs. Warner witnessed a bright meteor from
Horfield Common. It travelled slowly upwards from under
.Aldebaran to the planet Saturn and probably from a radiant
in the southern part of Taurus. The following are the real
paths of four meteors doubly observed on this notable night.

Heiglil

Heiglit

at

Velocity
per

Sepi. :m\.

II. M.

ItiM.

last.

M.

Patll.
M.

•second.

M.

K.idi.ilits.

cS 20 .

. 2—4

.. 66

.. 59 .

.. 45

... 30 ..

100=4-47°

.S 42 .

. Z—.'i

.. 79

.. 52 .

.. 34

... If. ..

4 4-28°

9 5 .

. > 2

.. SI

.. 48 .

.. 41

... 14 ..

6=4-27°

9 20 .

. 1—2

.. (I'l

.. ()9 .

.. 54

... — ..

11 9° 4- 34"

Other observations of meteors on September 30th would be
very acceptable for comparison.

THE FACE OF THE SKY FOR DECEMBER.

]w w. sh.\cklI':t()N. f.k..\.s.. a.k.c.s.

The SfN. — On the 1st the Sun rises at 7.44 ,aid sets at
3.54; on the 31st he rises at S.S and sets at 3. 58. The
equation of time on the 25th at noon is only 13 seconds, and
for ordinary purposes is negligible. Winter commences on
the 22nd, when the sun enters the sign of Capricorn at
10,54 p,m. ; this is the shortest day, the Sun rising at S.5 and
setting at 3.51. Sunspots and faculae may usually be
observed on the solar disc, though of late Spots have been
rather small. The positions of the Sun's axis, centre of the
disc, and heliographic longitude of the centre are gi\en
below : —

THE l'L.-\NETS.

Centre of Disc

Heliogiaphic
Longitude of

Date.

A.xis inclined
from N. point.

N. ur S. of

Sun's Equator.

Centre of Disc.

Dec. 2 ..

15" sy'K

o° 40 'X

192° 10'

7 ■■■

13° 57'E

0° 2'X

126° 16'

12 ...

11= 49'li

0° 37'i;

60° 23'

,, 17 ■■

9° 3i"i^

1° 14'S

354° 31'

22

f I2'E

1= 52'S

288" 39'

,, 27 ...

4° 49' K

2^' 29'.S

222- 47'

Jan. I ...

2° 22'E

3^ 5'S

■56= 56'

The Moon : —

Date.

Phases.

H. JL

Dec 6 .
„ 12 ..
,, 20 ...
,, 28 ...

C Full Moon

d Last Quarter

# New Moon

)) First Quarter ...

2 52 a.m.

5 46 p.m.

3 40 p.m.

6 48 p.m.

Dec. 7 ..
., 22 ...

I'erigee

Apogee

1 0 a.m.

2 6 a.ni

OccULTATION'S. — Particulars of the principal occultations
i'isible in this country are given in the table below : —

Date

Star's
Name

Disappearance.

Reappc

arance.

Mean

.\ngle
from N.

Meati

Angle :
fromN.;

'^

Tune.

point.
E.

Time.

point.

p.m.

p.m.

Dec.

J

29 Arietis

6-1

8. 10

102^

9.0

194"

6

B.A.C. 1754

5 7

6 42

a.m.

37"'

7.24

a.m.

296°

7

136 Tauii

4-6

1.46

19"

2. I I

337'^'

8

47 Geminorum...

5-6

5.23
p.m.

96-

6.22
p.m.

290"

8

w' Cancri

6-1

9 ,31

05^

10.24

305"

8

w- Cancri

6-2

9-54

.T.m.

127-

10.46

a.m.

244°

9

X Cancri

5 9

6.48
p.m.

123

7-44

[..in.

279

24

T,^ Capricorni .

5-3

5.25

22

6.2,

280

Mercury

—

Date.

Kight Ascension.

Declinalion.

Dec. I ...

II ...

21 ...

,, 31 ...

li, " ni.

17 5'

18 38

iS 34
17 43

S 25- 52'
S 24- 47'
S 22" 12'
S 20° 14'

Mercury is an evening star in Sagittarius setting about 5 p.m,
from the 10th to the 20th, but unfavourably placed for
observation. The planet is at greatest easterly elongation
from the Sun of 20 ' 58' on the 7th, whilst on the 16th he is
stationary, after which he describes a retrograde path, and is
in inferior conjunction with the Sun on the 25th.

Venus : —

Date.

Right Ascension.

Declination.

Dec. 1 ...
,, 11

21 ...
„ 31 ...

h. ni.

13 23

14 4

14 47

15 33

S 6° 26'

•S 9'' 55'
.S 13" 22'
S 16° 31'

Venus is a morning star first in Virgo, then in Libra ; she
rises in the E,S.E, at 3,15 a.m. on the 1st, and at 4.21 a.m.
on the 31st, As seen in the telescope the planet appears
gibbous, 0-6 of the disc being illuminated ; the apparent
diameter of the planet is 20",

M.\RS : —

Date.

Right Ascension.

Declination,

Dec. I .

,, II ...
,, 21 .
■ . 31 -

h. m,

3 48
3 35

3 26

X 21^' 31'

N 21" 10'
N 20° 58

N 21^' 0'

Mars is a very conspicuous object in the S,E. portion of the
bUy at sunset: he appears as a bright reddish star about 3^
South of the Pleiades, where he is describing a short retrograde
path ; the planet is at the stationary point on the 29th,

On the 1st he is due South at 11.9 p.m„ on the 15th at 9,57
p.m., and on the 31st at 8.49 p.m.; he remains above the
horizon till the early hours of the morning.

The latitude of the planet's centre is —13°, hence the South
Polar Cap is visible. The time of rotation is 24'' 37"" 22''-65,
which is equivalent to 14^-62 per hour, and the time of transit
of the Zero Meridian of the planet is as follows : —

Date.

Transit of Zero
Meridian.

Dale.

rran!.il of Zero
Meridian

Ii. m.

h. lu.

Dec. 2 ...

2 51 p.m.

Dec. U)

u 35 a.m.

., 4 ■■
,, 6 ...

., S ..

44..
5 10 ,,
0 2<) ,,

,, 21 ...
,, 1}^ ...

1 49 .,

3 3 >

4 17 „

to ,
12
., 14 ■

7 42 ,.

8 i; ..
10 .-s ..

., 2(1 ,
,, 31 ...

5 32 . .
0 46 .,
8 I ,,

,, 10 ...

11 21 ,,

469

470

KNOWLEDGE.

December, 1911.

With the above data the longitude of the centre of Mars
can easily be calculated for any moment. It may be noted
that the zero meridian passes through the bay of the Sinus
Sabaeus. The following well-known markings are visible at
9 p.m. on the dates mentioned below : — Am^orae Sinus on the
6th. Sinus Sabaeus on the 12th. Syrtis Major on the 19th and the
Mare Cinnueriuin on the 2Sth. Most of the markings require
at least a telescope of six inches aperture and good seeing to
discern any detail, though dusky patches can be made out on
the planet's disc with telescopes of smaller aperture. The
Moon appears near Mars on the morning of the 5th.
conjunction taking place at 3.55 a.m., Mars being 0" 50' to the
South.

Jupiter: —

The Moon will appear near the planet on the evening of the
31st, Saturn being 4° to the South.

Date.

Right .Ascension.

Declination.

Dec. I ...
„ 11 ...

,, 21 ...

,. 31 ...

h. ni.
15 44

15 5i

16 2
16 10

S IS" 59'
S 19° 2S'

s 19° 55'

S 20° iS'

Jupiter is a morning st.ar, rising at 6.50 a.m. on the 1st and
at 5.22 a.m. on the 31st; owing to his apparent proximity to
the Sun, the planet is not observable till the end of the month,
and for the same reason his satellites are inobser\ able. The
planet appears in Scorpio and is in conjunction with ji Scorpii
on the 20th. the planet being about 16' tn the South of the
star.

S.-^TURN : —

Date.

Right Ascen.sion.

Declination.

Dec. I ...
., 16 ...
„ 31 ■■■

h. ni.
2 53
2 J''
2 47

N 13° 58'

1.1 44

>■" 13 37

Saturn is a very conspicuous object in the evening sky look-
ing S.E. ; he appears about 10° to S.W. of the Pleiades and
Mars. He appears due south at 10.15 p.m. on the 1st,
9.12 p.m. on the 16th. and 8.11 p.m. on the 31st, that is, about
four minutes earlier each day.

(Jn the meridian he appears about 52 ' above the horizon as
the brightest star in that portion of the heavens, excepting
Mars, but he may readily be distinguished from Mars by his
lustreless appearance.

The planet may be seen in detail in quite small telescopes ;
even telescopes of only 2-in. aperture are sufficient to observe
details on the disc as well as the Cassini division in the ring,
using a magnification of 100, whilst the ring itself may be seen
with a magnifying power of 50. The dark or crape ring
requires at least a 4-in. telescope, but it is seen to better
advantage in larger telescopes. The diameter of the ball is
18". whilst the diameters of the outer major and minor axes of
the ring are 45" and 16" respectively. The Southern surface
of the ring is presented to us at an angle of 21° to our line of
vision ; thus the ring appears well open.

Uranus :-

-

Dale.

Right Ascension.

Declination.

Dec. I ...
,. 31 ■■■

h. m. s.
10 55 23
20 I 47

S 21" 20' 35"

S 21'' 2' 40"

l.'ranus is approaching conjunction with the Sun. which
takes place 20th January, and hence is practically unobserv-
able, as he sets about 6.30 p.m. near the middle of the month.

Neptune

—

Date.

Right .Ascension.

Declination.

Dec. I ...
„ 31 ...

h. m. s.
7 40 35
7 37 5S

N 20" 50' S"
N 20° 57' 11"

Neptune rises at 7 p.m. on the 1st, and at 5 p.m. on the
31st, whilst on these dates he is due south at 3 a.m. and 1 a.m.

He is becoming more favourably placed for obser\ation in
the evenings, as he is in opposition on Jaimary 13th.

The planet is situated in Gemini, where he is describing a
short retrograde path about 7° due south of Pollux and about
5° E. by S. of S Geminorum. but in small telescopes without
setting circles it is difficult to identify from the numerous
small stars in the same field of view. He may, however, be
detected by his motion, if observations are made on several
successive nights.

Meteors. — The principal shower of meteors during the
month is the Geminids. December 10th to 12th ; the radiant is
near Castor, in R.A. VIl'' 12", Dec. +55°. The meteors are
short and quick, and difticult to record accurately.

Minima of .Algol may be observed on the 14th at 11 p.m.,
the 17th at S p.m., and the 20th at 4.30 p.m. The period is
2'' 20'' 49™. from which other minima be calculated.

Telescopic Objects: —
Double Stars. — 1 Pegasi 21'' 17-5
4-5, 8-6; separation 36"- 2.

N

N.

N.

N. 19° 20'. mags.
55° 11', mags. 4-0, 8-0;
2° 17', mags. 3-7, 4-7;
29' 50', mags. 5, 6-4;

separa-

separa-

ir .Andromeda O"" 31-5'^
tion 36" -3.

a Piscium l*" 56-
tion 3" -6.

I Trianguli 2'' 6-
tion 5" ■ 5.

Clusters.— (W VI. 55, 34.)
to the naked eye and situated about midway between 7 Persei
and 5 Cassiopeia. These magnificent clusters are described
by Smyth as " affording together one of tlie most brilliant
telescopic objects in the heavens."

(M 34.1 A mass of small stars about the Sth magnitude;
not very compact. The cluster is just perceptible to the naked
eve about 5° North-West of .Algol.

separa-

The Perseus clusters visible

NOTICES.

ROYAL INSTITUTION.— A General Monthly Aleeting
of the Members of the Royal Institution was held on
November 6th, the Duke of Northumberland, K.G., President,
in the Chair. The Chairman reported the decease of
the Right Hon. Earl Cathcart. D.L.. J. P.. a Manager.
Professor G. L. Van der Mensbrugghe, Professor W. V.
Spring and Professor L. J. Troost, Honorary Members
of the Royal Institution, and resolutions of condolence with
the families were passed. The Highty-sixtli Christmas Course
of Juvenile Lectures, foimded at the Royal Institution in 1826.
by Michael Faradav, will be delivered this vear bv Dr. P.
Chalmers Mitchell,' D.Sc, LL.D., F.R.S., Secretary of the
Zoological Society, his subject being " The Childhood of

.Animals." The Lectures will be delivered on the following
dates, at 3 o'clock : Thursday, December 28th ; I')eceniber
30th, 191 1 : January 2nd. 4th, 6th, and 9th. 1912.

INTERNATIONAL CONGRESS OF ENTOMOLOGY.
CORRECTED D.ATE. — The Second International Congress
of Entomology will be held at Oxford, from August 5th to
10th, 1912, and not as previously announced. The President
of the Congress is Professor E. B. Poulton. D.Sc, F.R.S.
.Ml coinnnmications and entiuiries should be addressed to the
General Secretary of the Executive Committee. Dr. Malcolm
Burr, c,o F2ntomological Society of London, 11, Chandos
Street, Cavendish Stjuare, London, W.

CORRESPOXDEXXE.

THE FLICHT OF THE ALBATROSS.
To the Editors of " Knowlkdge."

Sirs, — We often hear of the mystery of how the Albatross
can fly without flapping its wings. I have often by the hour
closely watched these birds on the wing, and seen that they
make no movement save slight guiding and directing altera-
tions of tail and wing. The head is moved about freely to
look in all directions, and the bird will occasionally scratch
itself with claw or beak, for they always swarm with \ermin,
but usually there is no flapping of the wings at all.

In these days of fast steamers, as there are few opportunities
of watching their flight, may I record my evidence of how one
of these birds will thus follow a ship for many days and nights
together ?

First, they only fly in their characteristic manner while the
wind is blowing. As the wind drops they begin to flap : and
as a calm comes on they soon tire of flying by flapping and
settle on the sea like great ducks. Then when enough wind
remains to move the ship they are usually left behind and not
seen again. Why they so soon tire of flapping is because the
humerus (arm-bone) is very long, while the pectoral muscles
are comparatively small and supported by a small keel to the
sternum.

Presumably they use the wind to help them to fly. But
how ?

All the while they are flying they are repeatedly rising high
into the air, then swooping down close to the sea surface, and
then up again. If there was no friction nor other loss of
energy, the impetus of the swoop would enable the creature to
rise to as high a spot as it came down from. Or if it could
get from the wind a little impetus to replace the certain loss of
energy the bird could continue to rise and fall as long as the
wind blew. It does this.

W'hen there is wind at sea there are also waves. .As the
wind slides up the back of a wave towards the crest it is
directed upwards. The .\lbatross always swoops deep into
the trough of the sea, where it is somewhat sheltered from the
wind, and there, facing towards the on-coming wave, it begins
to rise close to the front surface of the wave. When it
crosses the crest the bird may be seen to get a distinct " lift "
from the up-current of air.

To fly by this method across the wind, or in the direction of
the wind, the .-Mbatross has to make curious gyrations, so as to
face the wind after each swoop. If this manoeuvre is pre-
vented, as by the distraction of some tit-bit or a quarrel with a
companion, the bird has to flap and fly like any other gull.

This mystery is as usual made by omitting a necessary
detail of description ; as also w-hen we are told that often
when placed on deck this sea-bird is sea-sick I It we were
told that while it was being hauled on board the bird had
gaped its beak wide open to get the hook out, and being
dragged through the crests of several waves it had thus
swallowed large quantities of sea water, then we should guess
that it was sick from sea water, not from the motion of the
ship.

How the Albatross can do without sleep for so long remains
a mystery. It sometimes looks half asleep while it executes
its monotonous movements, ^ Ao,-rr T^r-t-i-e

ROTATION ol- VEXUS,

To the Editors of " Knowledge,"

Sirs, — The April Number of " Knowlkdgk " contained a
short article of mine on the above subject, in which I advanced
some reasons for assuming that \'enus still has a rotation
period shorter than its year, even though this rotation might
be too slow to be detected from observation. It is interesting
to learn that since then M, Belopolsky has confirmed some of

his previous spectroscopic work, giving the planet a period of
1 ■ 44 days. This result is in accord with theory, and corrob-
orates to a great extent the early observations of Schroter
and De ^'ico, On the other hand Mr, Slipher has obtained
no indication of a rapid rotation from the spectrum of Venus,
which agrees with the direct visual work of Schiaparelli and
Lowell.

These conflicting observations of experienced astronomers
are very unsatisfactory, and are the more extraordinary as
each result has been confirmed by an independent method of
research. We can only hope that ere long some decisive
evidence may be obtained upon this, at present, baffling

'l"<^st'"n- B. G, HARRISON,

CLUSTERS AND NEBULAE.
To the Editors of " Knowleuge,"

Sirs, — Referring to my article " Clusters and Nebulae'' in
vour September number. I have just received a letter from Dr.
Fath. of the Mount Wilson Solar Observatory, Pasadena,
California, together with a minute print of one of his Lick
Spectrograms of the .Andromeda Nebula. Notwithstanding
its small scale there appear to be indications of lines corres-
ponding to those in the solar spectrum, and he states there are
other fainter lines (lost in the print).

I am accordingly sending you this note at his desire, so that
it may be seen that his opinion (quoted on page 344, column 1)
was not given without evidence. Dr. Fath also states in his
letter "Dr. Lockyer and Mr. Frank McClean were here a
few months ago, and saw some of the original negatives, I
believe they will agree that these absorption lines are well
marked in the originals," p -ly hENKEL

THE VELOCITY OF LIGHT.

To the Editors of " Knowledge,"

Sirs, — Surely your correspondent, G. R. Gibbs. is trying to
hoax your readers with his suggestion that light has its velocity
reduced by the earth's atmosphere to some twenty miles a
second because he can see a flash of lightning. Considering
that he admits that the observations for computing the velocity
of light actually showed a velocity of one hundred and eight\-
six thousand miles a second near the earth's surface, it is
difficult to see on what principle of logic he yet considers that
twenty miles is the correct figure. Does he really imagine that
a brilliant spark will become invisible if it takes less than
one-tenth of a second to accomplish its path ? Considering
that the spark of an electric machine is visible when one-tenth
of an inch long, are we to infer that such sparks only travel
one mch in a second ? CH-^RLES E, BENHAM.

To the Editors of " Knowledge,"

Sirs. — Theosophists state that the Earth has a motion which
has not yet been discovered by Astronomers,

This motion consists of the rotation of the Earth's axis
about its centre thereby causing the Earth to " turn turtle " as
the saying is, in other words that in time the Southern
Hemisphere will face the Pole star in a similar manner that
the Northern Hemisphere does at present.

If this statement is correct it would fully account for the
various large changes in temperature which appear to ha\e
taken place in the different parts of the Earth,

Does not the dift'erence in the inclinations of the axes of the
pl.uiets to the planes of their orbits point to the possibility of
all the planets being subject to this motion ?

F. G. STOPFORD (Admiral).

471

472

KNOWLEDGE.

Df.cember, 1911.

THE COAL RESOURCES OF
KINGDOM.

THE UXITl-D

To the Kditars of " Kmiwledgic."

Sirs. — Attention has again bt-fn attracted to the contents
of onr natnral coal store. Experts have pointed ont that we
are rapidly exhausting the coal resom'ces of our coiuitry, and
they estimate the life of our coalfields to be less than two
hundred years. Half a century ago, experts gave a similar
estimate, and we have during the last fifty years withdrawn
millions of tons from the natural store.

It is of interest, and as well assuring, to note that whilst the
Royal Commission of 1871 estimated the "available coal" at
yO,207, 285,000 tons, the final report of the 1905 Commission
gave the quantity of available coal as 100.914,568,167 tons.
Thus the figures of the last Commission exceeded those of
1871 by 10,707.383,167 tons, and it must be considered that
during the period 1871-1905. no less than 5.694.928,507 tons
had been brought to bank.

Since the last Commission sat, there ha\e been considerable
additional coal areas proved in Lincolnshire and in the South
of England. A reasonable survey of the coal "in store"
within the United Kingdom gives ample assurance that onr
coal supplies are safe for the next five hundred year.s.

National economy requires a periodical stocUtaUing of
available coal, and demands that the coal drawn from the
natural store shall be economically utilized.

Every ton of coal mined reduces the assets of the nation,
and it is a national duty to prevent avoidable waste, in
(rt) winning coal from its natural bed. and (6) in the con-
version of the potential energy of the coal into useful work.

Few people realize the amount of power which is stored
in coal. One tea.spoonful of British coal contains sufficient
energy to lift two modern locomotives to a height of one foot.
.A piece of coal the size of a man's fist has power enough to
throw a weight of thirty pounds to a height of one-and-a-
quarter miles. In our houses we use coal by the shovelful :
but if the heat stored in the coal was efficiently utilized the
coal-spoon would displace the shovel. To boil a gallon of
water we require a large fire ; yet the heat produced by one
pound of coal is sufticient to raise to boiling point one hundred
pounds or ten gallons of water.

Industrially we only utilize one-tenth of the power stored in
coal : the balance (nine-tenthsl is used up or wasted in the
process of securing the one-tenth.

A National C'onservancy is needed to protect the national
store of solid fuel, and to obtain a better efficiency in the
every-day use of coal. The industrial and maritime power and
progress of our nation is founded on the enormous stores of
first-grade coal and the large annual production.

Within the United Kingdom no less than two hundred
millions of tons of coal are consumed annually, and the yearly
export is well over sixty millions of tons. The important
bearing of these figures on our national industries is quite
obvious.

It is a national duty to win every ton of coal from the

natural store in the most economical manner possible, and to

obtain from the coal produced the highest possible value.

. These points are worth the attention of the nation's economists,

and provide a wide field for profitable scientific investigation.

.MVLi:S BROWN.

QUERIES AND ANSWERS.

Readers are invited to send in Onesfions and to answer the Queries whicli are printed here.

gUESTIONS.

55. THE NEW ASTRONOMY.— I should be very grateful
for any information as to the v.iriability of double stars, and
especially I should like to know of binaries that are doubly
variable. If spectroscopists would look for lines of planetary
nebulae about variable doubles, about the Cepheids, and about
variables whose light curve ascends more quickly than it
descends, they might supply useful information. I should
also be glad to know if another variable could be found in the
neighbourhood of variables with that kind of light curve when
one exists alone. It would also be valuable to the theory to
find if nebulosity at minimum exists in the case of any of the
Cepheids. On page 80 in "The Birth of Worlds and Systems ''
(Harper's Library of Living Thought). 1 have given a table of
variables that I picked out from Gore's list; nebulosity should
be looked for between the constituents of each pair, or perhaps
surrounding them if close. The lines of planetary nebulae
should also be looked for about them. The old measures
should be compared with the new ones, to see if the stars are
still separating, or if they are in long ellipses. Their exact angle
and distance should now be determined to make future com-
parisons. I should also be pleased if the position where novae
have appeared were examined for nebulosity, for faint fluctua-
tions of light, and for the lines of planetary nebulae. The
Owl and Dumb-bell nebulae seem to me to be planetary nebulae.
I should be glad to know if they show the characteristic lines:
the singular bilateral symmetry suggests that each is a third
body struck from grazing suns. In the case of the Owl the
eyes may be the two original moderately rare bodies; it
would be interesting to know if any changes of form or
structure in these or other planetary nebulae have been
observed, and it would also be desirable to know the several
chemical elements of the sphere-in-sphere constituents of these
nebulae.

Mr. McCarthy, in his encouraging letter, speaks of the exact
comparison he fintls to exist between the deduced properties
of the tliird body and those observed in Nova Hersei.

Mr. Rafi'ety is a careful spectroscopic student: I should like
to know if he has compared the two. and to have his opinion
as to temporary and variable stars being the result of partial
impact and the third body. ^ ^^. gjcKERTON.

56. WATER SNAILS [PLANORBIS CORNEUS).—

Would one of your readers describe the parasite of the Water
Snails iPlanorbis Cornells, and so on). It appears to eat
into the shell and ultimately causes the death of the host.

J. M.

57. SOLAR SPECTRUM.— Why in photographs of the
solar spectrum from diffused daylight (a bright sky) the lines
are never sharp, as in the case from direct sunlight, though
the slit has the same width ? r A S

58. In a train of prisms for great dispersion, is there
interference of light where the two beams of light cross ?
If not, why ? .And if there is, why is there no interference
effect in the spectrum ?

C. A. S.

ANSWERS.

51. THE GEOLOGY OF SOUTH DORSET.—
Information asked can easily be obtained by turning up
" Kelly's Directory of Hampshire. Wiltshire, Dorsetshire and
the Cliannel Isles, 1907," where an outline of the Geology of
Dorsetshire is ably described by W. Jerome Harrison, F.Cr.S., in
which he not only gives a full account of the Strata. .Minerals,
and Fossils, but also of the names and writers of the mmierous
books treating on the Geology of the district. There is also
a splendid collection of fossils in the Museum at Dorchester.
The publications of the Government geological survey maps
and reports. Map Sheet 16, Poole. Wareham and Swanage,
take up the latest details : these can be obtained from
.Mr. Henry Ling. Bookseller. Dorchester, Dorsetshire.

A. .M. W.

THE FACE OF THE SKY FOR JANUARY, 1912.

By A. C. D. CRO^rMRLI^^ r>.A.. D.Sc, F.R.A.S.

The foUowiiii; table gives the Kii;ht Ascension and Declination
of the Sun, Moon and Planets at iiiter\als of 5 days, at
Greenwich noon.

The following table gives for the Sun, Mars and Jupiter: —
P the Position .\ngle of the Sun's or Pl.anet's North Pole,
measured from the North Point of the disc towards the ICast,

The Sun is nearest to the earth on Jan. i. distance
'Jlj million miles; it is commencing its northward march,
slowly at first, but with increasing speed. At Greenwich it rises
at 8.8 on Jan. 1, sets at 3.58; it rises at 7.44 on Jan. 31. sets at
4.43. Its semi-diameter diminishes during the month from
Id' is" to Hi' 15". The minimum of simspot activity is

D.itf.

Sun.

Moon.

Mercurj'.

Venus.

ll.nrs.

Ceres.

Jupiter.

Saturn.

Neptune. j

R..\.

Dec.

R.A. Dec.

R.A.

Dec.

R..\.

Dec.

R..\.

Dec

R.A.

Dec.

R.A.

Dec.

R..^.

Dec.

R..\.-

De,-.

h. m.

h. 111. ^

ii. m.

h. ni.

li. nl.

0

h. in.

h. m.

h. 111.

h. in.

]:m. I

i8 42-3

S..VI

3 55-> N.2,3

17 398

S.20-2

15 37 9

S.16-8

3 25-6

.\.2I-0

8 2. -5

N.28-7

16 I) *3

S.2o"3

2 47!

N.13-6

7 37*9

X.2°o

6 ..

19 4-4

22-6

0 5'6 N'.2i"7

■7 35-3

2°"5

16 I -8

i8-2

3 =7'°

21*1

8 17-5

29*3

16 15*4

20*5

2 46*7

13-6

7 37"3

21 '0

,, 11

19 26"2

22-0

13 22'1 .S, 8'2

17 46-0

2 I ■-'

16 26-2

19-4

3 29 '5

21*3

8 13*1

29*9

16 19-5

20*7

2 46*4

13*6

7 36*7

2l"0

„ i6 ..

19 47-8

2I"I

17 279 274

t8 5"2

22"!

16 5i"i

20-4

3 33'2

21*5

8 8*2

3o'5

16 23-4

20-8

2 46*3

13*6

7 36-1

2r"o

,. 21

20 9*2

20*1

21 45"! S.i8'3

iS 2Q'9

22-7

17 16-4

2 I "2

3 37 '9

21*8

S 3-=

3i'i

16 27*2

21 0

2 46*4

13*7

7 35*5

:!i"i

„ 20 ..

20 30-2

IQO

I 31-2 N. 9-5

18 58-0

22-9

17 42-1

21-7

3 43 '6

22*1

7 58*2

»t3''5

16 30*9

21*1

2 46*6

,. ''3'7

7 34 '9

2I"I

., 3' ■■

20 50'9

S.:7-7

6 2i'9 N.28-1

19 28'!

.S.22"7

18 8-1

S22-0

3 5^''^

N.22-4

7 53'4

N.3I-9

10 34*4

S.2r2

2 47*1

N.i3*8

7 34'3

N.2I-I

Tahle 1.

B the Hcliographical or Planetographical latitude of the
centre of the disc, and L the Heliographical or Planetographical
longitude of the centre of the disc, which in the case of the
Sun or Jupiter is reckoned from an arbitrarily chosen zero
meridian, in the case of Mars from the marking Fastigium
Aryn (formerly called Dawes Forked Bay). That of Jupiter,
system II, originally coincided with the great Red Spot. Two
values are given for Jupiter : I corresponds to the equator. II to
temperate zones. T the time of transit of the zero meridian
is also given for each of the given dates. Here and elsewhere
in these pages the time used is Greenwich Civil Time, day
beginning at midnight, and the letters in (morning), f (evening)
are used as abbreviations for a.m. and p.m. The quantities
P, B, are also gi\en for S.-iturn, and serve to indicate the
position of the minor axis of the ring, and the amount of its
opening. The additional quantities O. q, given for Mars are
the Position Angle (from North Point towards Fast) and the
amount, in seconds of arc, of the greatest defect of illmnination.

expected in 1912 or 1913, but cannot as yet be predicted with
mathematical accur.acv.

The Moon is Full, Jan. 4. l"30"'f.; L.n.. Ian. 11. 7" 43"' ;)j..
New, Jan. 19, ll'' 10" /;;.; F.O.. Jan. 27, S" 51'" in.: Perigee;
Jan. 4. 2'' e., distance 221.400 miles (an unusually close
approach) ; .Apogee, Jan. 18, 2" in., distance 264,600 miles.

The following gives the dates of the Moon's maximum
librations: Dec. 29, S° £.; Jan. 5, 6° S.; Jan. 10, 8° W.; Jan.
19, '-■ N.; Jan. 26, 7° E.; Feb. 1, 7' S. The letters E. \V.
indicate that the region brought into view is on the E^ast (Mare
Humorum side), or West (Mare Crisium side) respectively.
The letters N. S. indicate that the regions brought into view*
are at the Moon's N. or S. Poles. Observers will do well to
watch their libration opportunities to improve our knowledge
of the regions near the limb.

The occultations visible at Greenwich are given on page 475.

Mercury is a morning star. It reaches W. elongation

Date.

.Sun.

Mars.

Jupiter.

Sat

urn.

i"

B

L

P B

L Q

q

T

P

B

'*.

''.,

T,

T„

P

B

.,

h m

0

h m

h m

Jan. I

2*4

S.3*I

156*9

323'2 S-I4-8

490 77*8

■73

8 39 in

10*6

S.2*9

26*5

86*5

a 7e

7 32 =

359'5

S.2o*5

359'9

3*6

91*1

323*2 14*7

3*., 77*6

■So

11 48 in

lO'l

2*9

93*2

117*1

7 14 =

0 42 e

559 5

20*5

)> II

357'5

4'-'

25*2

323*3 14 '5

3i6*S 77*5

*86

2 57 e

9 7

2*0

104*1

147*7

5 21 e

5 5> e

359*5

20*5

,, 16

355'!

47

3I9-1

3=3'4 i4'i

270*3 77*6

-90

6 Se

9*3

2*9

232*9

178*5

3 2Se

5 oe

359'5

20*5

,, 2T

352*8

5 '2

253-6

323 6 I3"7

223*0 77*7

*91

Q 30 C

8*9

2*9

301*2

209*2

I [ 20 e

4 oe

359*3

20*5

„ 26

3SO'6

.Vb

187*7

323*8 1^*2

176*7 78*0

*Q2

—

8*6

2*9

10*8

240*0

9 ^i e

3 18 e

359'5

20*6

„ 31

3484

S.6-0

121*9

324*1 .S. 12*6

129*6 78*4

'92

3 S in

8*2

S.2*9

79*8

270*9

7 39 e

2 27 e

359'5

S.20-S

Table 2.

The

■alues of T, T,, for Jupiter on intermediate

days may be found by applyin.L;
respectively.

multiples of 9" 505". 9"

It should be mentioned that L is reckoned in the opposite
direction on the Sun from that used on Mars and Jupiter.
This difference is unfortunate, but it has become established
and cannot now* be altered.

The two systems may be best explained thus: in that
used for the Sun the longitudes of Bombax* and New York
from Greenwich would be 73', 286" respectively ; in that used
for Mars and Jupiter the same tw*o longitudes w*ould be
Bombay 287°, New York 74°.

(24° from Sun). Jan. 15. It is 6° N. of Moon, Jan. 17. h'" in.
Its diameter diminishes during month from 9" to 5"; the
illuminated part of disc increases from i to §.

Vl-.NUS is a morning star, pretty well placed for observation.
It is 6° N. of Moon, Jan. 15, 5*" e. Its diameter diminishes
from IS" to 15"; the illuminated part of disc increases from
S to t

Mars has passed opposition, but is still w*ell pl.*iced for
observation. The vernal equinox of the Northern Hemisphere

473

474

KNOWLEDGE.

December, 1911.

occurs on Jan. 14. His diameter diniinislie.s from IJV' to 10".
Veiling of surface details by mist or cloud in the Martian
atmosphere seems to have occurred in several regions of the
planet in October, according to MM. .Antoniadi. Jarry-
Desloges. and others.

Ceres, the largest of the asteroids, is in a %ery favourable
opposition in January, being in high north declination, and
also near perihelion. Its diameter is 4J() miles, just I of the
Moon's, and it will be of the 7th magnitude, and thus easily
visible in the smallest telescope or binocular; a map of
surrounding stars is given, which should make it easy to pick
the object up and follow its motion from day to day. The
brightest stars in the map are of mag. 5h, the faintest of
mag. 9i. Faint stars are onl\- shown when fairly near the
planet's track.

Jupiter is a morning star, and just beginning to become
observable after conjunction with the Sun. Its Equatorial
Diameter increases from 32" to 34" ; the Polar is 2" less. The
defect of illumination on the West limb is 1". The configura-
tions of the satellites as seen with an inverting telescope at
6'' in are : —

D.iy.

vVest.

East.

Day.

West.

East

Jan. I

4

C

13

Jan. 17

34

0

12

2

41

0

2

,. iS

5 12

L:

.> 3

43

0

12

„ 19

432

i^'

I

,. 4

431

u

,, 20

41

1 '

32

.. 5

43

u

I

,, 21

4

U

123

,, 6

41

p

32

,, 22

421

0

3

>. 7

4

o

1 -.

■■ 23

42

0

13

,, s

2'

o

3 '•

• • 24

43

2

I*

.. 9

I

u

34 2«

. .. 25

31

0

4

., lo

3

^■^

124

,. 26

32

0

14

,, 1 1

312

->

4

.: 27

'3

0

24

,, 12

.i2

14

,. 28

0

12^,4

.- '3

I

-

324

„ 29

21

0

34

,, 14

''-'

1234

„ 30

2

(1

'.34

" 15

21

(.^

-t

" 31

3

(^

24

I*

„ i6

2

o

4

The following phenomena are visible at Greenwich : —
1" 5" M)"' in. I. Oc. R. : 2" 6" 14™ ni. IIL Tr. E. : /" 7" 24'" ;;;.
I. Sh. I.: S" 7"40""«;, I. Oc. K. : 9'' a*" 23'" ,n. III. Sh. I. •
7" ]'" ;«. II. Oc. R. : 7" 12" ;«, III. Sh. K. ; 15" 6" 34™ 52^" ni.
I. i:c. D. ; 16" 4''40'" ;;;, I. Tr. I.: 5" 21'" 1 ■)",„, II. Ec. D. ;

5" 58'" m, I. Sh. E. : 0" 53'" ;);. I. Tr. E. ; 18" 4" 37'" in II..
Tr. E.; 20" 5" 14'" in. 111. < )c. R. ; Zj'^ 5" 3S'" ni, I. Sh. I.;
6" 38'" I. Tr. I. ; 7" 51"' ;/;. I. Sh. E. : 24" 6'' S'^m, I. Oc. R. ;
25"4''44'" ;». II. Tr. I.: 5" 18'" ;». II. Sh. E. ; 7" 23'" /)(. II.
Tr. E. : 27" 5" S™ 5'' w. III. ICc. R. ; 7" 35"' m. III. Oc. D.;
30J 7" 31™ „,. I. Sh. I.; 31" 4" 50™ 17' in, I. Ec. D. The
eclipses take place high left of the disc in an inverting telescope,
considering the direction of the belts as horizontal.

S.\TURN is still well placed for observation. Its equatorial
diameter is 19". major axis of ring 44", minor axis 15". The
shadow of the ball on the ring is visible on the East side.
The satellites except the outer ones, lapetus and Phoebe, are
in almost the same plane as the ring, so their apparent orbits
are widely open ellipses. The times of some Eastern Elonga-
tions are given ; intermediate ones are foimd by applying
multiples of l" 21" for Tethvs, 2" 18" for Dione, 4" 12.1"' for
Rhea.

Tethvs, 2" 6" c : 8" lO" in ; 14" 2" in : 19" f>" c : 25" lo" ;/; ;
31" 2" ;;/. Dione 2" 3" c ; 8" 2" ni ; 13" 2" c ; 19" l" in:
24" noon ; 29" ll" e. Rhea 5" lO" in ; 14" ll" ;;; : 23" noon ;
Feb. 1" noon. For Titan and lapetus, E.W. stand for E. and
\\'. elongations, I.S. for inferior and superior conjunctions.
Titan 5" 6" /;; W. 9" 4" in S, 13" 8" /;;. E, 17" 9" in I., 21" 5" //;
\V, 25" 3" in S, 29" 7" /;/ E. lapetus, Jan. lO" 9" c I.
peb. 5' 8 ' in W. This satellite is much easier to see W.
than E. of the planet : it is presumed to rotate in the same
time as its revolution.

Uranus is in\isible. being in conjunction with the Sun on
January 20th.

Neptune is very favourably placed, being in opposition on
January 13th. It is of the 8th magnitude. 2:{" in diameter. .\
map is given of the stars near its path. Their magnitude
ranges from 6.J to 9.1. With its aid a powerful binocular or a
li-in. telescope should find the planet. In December, it is
7i" south of Pollux. Its satellite. Triton, is too faint to justify
the inclusion of an cphemeris here.

Comets. — The numerous comets visible in England in the
autumn have now passed to the south, and become much
fainter. Ephemerides are given for the use of southern
observers ; that of Brooks's comet is due to Dr. Smart.

It is hoped that Ouenisset's Comet will be observed as
long as possible in the Southern Hemisphere, as its orbit
resembles that of 1790 III. and its identitx- appears possible.

BROOKS'

COMET.

j

QUENISSET'S COMET.

Date.

1
ll.

m. s.

S. Dec.

Log. r.

Log. A j

Date.

R..\.
h. m. s.

.S. Dec. 1 Log. I-.

Log. A

Jan. 3

14

41 0

44

13'

0-1738

0-2588

Dec. ;i

15 49 37

29" 18'

00806

0-2,67

/

14

47 S

45

jj

0-1923

0-2660

Tan. 8

15 49 J^

34 37

0-1171

0-2496

,. 1 1

14

.i2 56

46

49

0 2099

02724

„ 16

15 47 7

40 1 1

o-i;i6

0-2406

.. 15

14

58 12

4S

I

0-2266

0-2781

.. 24

15 42 28

45 59

0 - 1 8 58

0-2312

,. 19

1,1

3 4

49

12

0-2424

02833

Fell. I

S2 1

0-2141

02226

.. 23

I-,

7 12

50

19

02576

0-2878

9

15 '7 52

58 S

0 2421

0-2156

.. 27

'i

10 44

51

24

02722

0 2918

17

14 50 I

64 5

0-2684

0 2124

.. 3'-

I ;

13 44

52

27

..•2S60

0-2953

.. 25

14 2 q

1)0 10

0-2929

0-2139

1-el,. 4

li

16 0

17 40

53
54

28

27

02993
0-3121

0 2985
0-301 1

1

12

M

1 8 24

55

25

" 3245

0-3037

Borrellv's Periodic Comet will probably be an easy

,, 16

15

18 24

5<'

19

o'3363

0-3002

telescopic object in December and Januarv in both hemis-

,, 20

15

17 24

57

II

0-347!^

0-3083

pheres. The following epheineris is bv Dr. Smart, from

., 24

13

15 32

5S

I

0-3588

0-3102

M. F'avet's elements, taking 1911, December 18-01

'j

12 40

5i>

4b

0-3695

o-3"5

Greenwi

=h Mean Ti

ne as the d

ate of perih

rfion.

(Continued on page 476.)

December, 1911.

KNOWLEDGE.

475

Date.

Star's Name.

Magnitudes.

Disapp

M,,,n.-.

Reappearance. |

xVngle from

Ant^le from

Mean Time.

N. Pt. E.

Mean Time.

N. I't. E.

h m

h \n

Jan. I

32 Tauri

5-8

5. He

67°

6. 17 e

243°

,. I

BAC 1238 ...

6-5

7-5' e

354

8. 1 2 L-

3.9

2

62 Tauii

6-1

5 39 '"

35

—

,, 2

BD + 26'' 7q6

6 8

10.16 e

77

—

„ 3

KAC 2023

67

9. Se

■57

—

—

., 4

BD + 27° 1164

6-9

4.40 m

90

—

.. 4

BD + 27° 1194

77

6.32 m

83

—

_

,. 4

BAC 23S3

6-5

5. 0 e

43

5-35 <;

315

., 5

c Geminoium ...

5 '5

4.10 ni

90

5- ^> m

304

,, s

1 Leonis

5 '3

6.22 m

160

7. 12 rU

267

,, lo

7; Virginia

40

0.31 ni

1S2

I. 2 m

241

., i6

43 Ophiuclii

5 '4

—

—

7. 1 2 m

248

.> 25

73 I'iscium

6-2

8 45 e

56

9-47 L-

247

,, 26

BAC 542

7-0

5.21 e

31

„ 26

S4Ceti

60

7.44 e

120

—

—

,, 27

BAC 609

6-0

0.25 m

60

—

--

,. 27

IT Arielis ...

5-2

11-45 e

87

0.39 m* ) 23S 1

„ 29

BAC11S9

5 '9

1.47 m

114

2. 30 m

226

,, 29

Mar.s

2.34 m

74

3.24 111

266

„ 29

BD + 24''674

6-8

8.16 e

1 08

—

.. 30

K.^C 1754

57

4-43 e

106

5-38 e

22S

,, 30

BD + 27'' SSo

7-0

IO-33 e

61

— ] —

., 31

136 Tauri ...

4-6

0.20 ni

45

I. 2 m 321

,, 31

604-27" 94?

7-0

2.52 m

98

T.\Br,E 3. Occultations of stars by the Moon visible at Greenwich.

The asterisk indicates the day following that given in the date cohinin. O'' is used instead of 12''. The occultation of
Mars is not very favourable for observation, the Moon setting as the planet re-appears.

I I

. I

54
I

bn. 31

• J:,n, =5

J.,nV ,„

■ la.fV

Jan, ,3,

Jar

Jan* ^.

Jnn.

Figure 1. St.ars near the path of Ceres. January, 1912.

47fi

KNOWLEDGE.

Dkcembf.r. lyil.

Borri-:i.i,y's Comkt.

Date.

K. .\.

Dec.

I.og. r

Log. A

ll. Ml. S.

Dec. i ..-

2 50 24

.S.

,S 3.S'

0-1492

07063

... "3

2 -iS 0

i\

0 S

0-1472

9-7120

., 21

2 43 10

Ji v-,

0-1471

9732^

. , 20 .

2 42 :~2

17 3

n.I4SS

9-7<'53

Ian. ti .

2 45 52

24 12

015=3

9-.S052

.. 14 ■

2 52 44

30 17

"■1574

9-8491

22

.3 3 2.1

35 15

01D41

9-i!93>

30 ..

3 17 2S

iS.

39 37

0-1720

99376

Meteor Showers. — The following list of radiants for
January is due to Mr. \V. F. Denning.

Dale.

Radiant.

Notes.-

R..A.

Dec.

Jan. 2-3

. • 3

,, 11-23. ..

.. 17
„ 17-23...
„ 25 ...
„ 29 ...

230

136
220
295
159
131
213

^' 53
\ 41

N >3

N 53
N 27

N 32

N 52

Hiilliant shower, swift, loni;-

paths.
Swift.

Swifl, streaks.
Slow, l)iit;ht.
Swift.
Swift.
\'ery swift.

V.\RI.\BLE St.-\RS. — The following list gives every third
niiniinuin of .\lgol. Its magnitude ranges from 2-3 to 3-5.
Period i'' 20" 4<r. Jan. 6'' 9'V., 15'' ll"ii,.. _'4'' _'")».. Feb. 1''
4V.

,.i Lyrae ranges from 3-4 to 4-5.

Max.

Principal Min.

Max.

Secondary Min.

Jan. 3'i q'hu.
., 16 7 /;/
,, 2'l 3 w.

19 11 OT.

9" 3"''-
22 I <.

I2'l 11''.'.
25 I" '-

Double St.-\rs. — The period over which any double star
can be observed is nearly always several months, and in
some cases the whole year, But in order to make a distribution
into months. I am adopting the principle of taking those which
cross the meridian between 9'^ and ll'' p.m. on the 20th of each
month, i.e.. in January the limits of Right Ascension are a"" to
7'', in February 7"* to 9*^, and so on. Merely a brief selection
of double stars, clusters and nebulae within tliisc limits can
be given.

The angle is measured from North towards East.

I I

• I

n<rr. ,

J.ln.

F.-h. ,„

Mar.

FiGfRE 2. Stars near the path of Xcptune. December. I'lU. to .-\])ril. 191^

20

December, 1911.

KNOWLEDGE.

477

Star.

Riyht

Ascension.

Dec

lination.

Magnitudes.

Angle.

Distance.

Colours.

h.

ni.

S.

p Orionis ...

5

S

40

2

46-X

5.8

"3"

7

Yellow, blue.

I Leporis

5

S

10

1 1

sss

4.10

337

12

liluish-white.

K Leporis ...

5

9

10

Ij

"3S

5-8

.558

3

Yellow, blue.

'■iigel

5

to

17

8

iS.S

1,8

2Q2

10

Yellow, blue.

The companion is an exceedingly cli)se double.

iiS Tauri

5

23

44

25

4'N

6.7 202"

5

White, blue.

X Orionis ...

5

30

12

9

52 X

4.6 43

5

Yellow, purple.

fl'Orionis

5

30

55

5

27 s

The Trapezium in tlie Great Nebula.

(T- Orionis ..

5

34

30

2

39 s

A quadruple star, the principal being an exceedingly close pair,
with more distant companions of 6 mag., 7 mag., 10 mag.

S' Orionis

5

36

10

2

oS

2-5

156

2"

N'ellow, blue.

4 Lyncis

6

H

0

59

25 X

6,8

103

I

White.

8 Monocerotis

6

19

2

4

30 N-

4-7

24

■3

Golden, lilac.

II Monocerotis

6

24

30

6

58 .S

5-5.''i

i 106

7 1
3 1

Triple star.

12 Lyncis

6

38

24

59

31 \

5.6,7

1 I 16
1 306

1 1
8 1

Triple star.

Lai. F. 967

6

40

30

55

SI X

6.6

25S

s

YelloNv.

14 Lyncis

6

45

0

59

36 X

6,7

75

i

Orange, blue.

38 Geminorum

6

49

36

13

iSX

5-8

160

6

Yellow, blue.

fi Canis Majoris

6

52

3

'3

56 s

5.8

3

Orange, red.

Piazzi VI 301

6

58

35

52

53 ^•

0.7

'55

3

White.

Clusters -\xd Nebul.^e.

M 38

M I

M 42

M 37

.\I 41

K

A.

5"

221"

5

28

5

30

J

45

6

■,

6

26

6

43

Dec.

35° 49'N-
21 57 N.

5 ^7S.
32 32 N.

24 21 N.
4 56 N.

20 38 S.

Cruciform cluster.

The Crab Nebula; l' N.W. of

S" Tauri.
Great Nebula in Orion.
Even in smaller instruments

extremely beautiful (Webb).
Very rich field.

Fine cluster, visible to naked eye.
\'isible to naked eye, 4° S. of

Sirius.

Editori.\l Note.

In accordance with the wishes of many of our readers Mr.
Shackleton has, for the last few months, kindh- made his
notes on " The Face of the Sky " deal with the first week or
so of the month following the date of issue of the Magazine,
so that any delay iu the receipt of the latter might not affect
the usefulness of the column.

With this number, on account of the increasing pressure of
other duties. Mr. Shackleton has given up the work which he
has so well carried on for many years, and Dr. Crommelin,
who has been so good as to undertake the duty, will prepare
his notes a month ahead, so that " The Face of the Sky for
January "' is printed here. Our readers abroad will thus be in
the same position as those at home.

NOTICES.

TRANSMISSION OF DISEASE BY MEANS OF BOOKS.
— The undersigned is preparing a paper upon " Books as a
Source of Disease," to be read before the next " International
Congress of H\-,giene." and in order to obtain data, respect-
fully requests the readers of this note to send him an account
of any cases the source of which have been traced to books
or papers, or where the evidence seemed to make books or
papers the offender. He would also further request informa-
tion where illness or even death has been caused bv the
poisons used in book-making.

All the information possible is wanted to present as com-
plete a paper as possible. As in the case of insects which we
now know to be " carriers of disease." it is first necessar)' to
collect scattered evidence in order to show that there is real
danger in books ; and this will compel better care to be taken
of libraries and books, and improve the health of mankind. —
\Vm. R. Reinick, 1709, Wallace Street, Philadelphia, Pa.

BOTANY IN THE " ENCYCLOPAEDIA BRITAN-
NICA." — .^ careful perusal of the botanical articles in the
eleventh edition of the " Encyclopaedia Britannica" shows that
the revision of this section of the great work has been entrusted
to rehable and experienced hands. The result is that, with a
certain amount of addition in some directions and wholesale
excision in others, this collection of articles would form an
exceedin.gly good basis for a modern text book of Botany —
certainly a much better one than any English work so far
produced. Here and there the antiquity of the illustration
blocks reminds one irresistibly of the fount whence the authors

of " Wisdom While You Wait " drew so largely in writing
their amusing skit, and it seems a pity that important articles
on those departments of Botany in which so much recent
literature is available have not been illustrated more
adequately by new figures from that literature.

Most of the articles dealing with the great divisions of the
\egetable kingdom — e.g. Algae, Fungi, Bryophyta. Pterido-
phyta, Gymnosperms — are models of hicidity, though in some
cases interesting points have been omitted owing to the
doubtless unavoidably small limits of space allotted to the
compilers. In some cases this limitation has not permitted
of the inclusion of speculative or controversial matter or of
discussions regarding the relationships of the various groups.
We get the facts, but very little of the " salt of morpho-
logical ideas," to use an expressive phrase of the late Sir
Michael Foster's. However, there is in most cases a well-
selected bibliography at the end of each of the longer articles,
whence the reader may find guidance to the literature of the
subject dealt with.

It is difficult to imagine what general principles, if any.
underlie the selection of the biographies given in the list of
botanical articles. Some of the naturalists whose Hves are
summarised can hardly be said to bulk largely in the history
of Botany or to have advanced the science to such an extent
as did many workers whose names are missing from the list.
Among the omissions, one may mention such names as those
of the two Gartners (K. F. and J.), Hedwig. Ingenhouss. the
Schimpers. Spruce and Unger.

NOTES

ASTRONOMY.

By A. C. D. Crommelin. B.A.. D.Sc, F.R.A.S.

WIRELESS TELEGRAPHY FOR TIME SIGNALS.—
L'Astrniioiiiic for August gives au interesting account of the
manner in which the Time Signals of the Paris Observatory
are distributed by wireless telegraphv.

The standard clocl;s are kept in the " Catacombs," ninetv feet
under ground, where there is a practically constant temperature
of 11°-S C. the variations in several years being under 0"-02.
The sidereal and solar clocks can be compared at a distance,
their beats being rendered audible by microphones.

\\'ireless telegraphy was first used for distributing time
signals on 23rd May, 1910. It is probably only a question of
time before these or similar signals are available to ships in
any part of the world, which will completely solve the problem
of longitude at sea, with an accuracy formerly undreamt of.
This and the gyro-compass are two re\-olutionary impro\-e-
ments in navigational methods during the last fifteen months.

The mean solar clock is put right, as at Greenwich, by an
electro-magnet that can either aid or oppose the action of ■
gravity on the pendulum. Several warning signals are sent by
hand in a pre-arranged manner to give notice of the actual
signal, which is sent automatically by the clock, and goes
through a relay to the Eift'el Tower, whence it proceeds by
wireless telegraphy. A note in the Observatory recently
stated that a clockmaker at Canterbury regulates his clocks bv
the Paris signals, which were recently changed to accord with
Greenwich Time. Germany has also a system of signals
despatched from Norddeich, and Rio de Janeiro is about to
follow suit. The French propose to use the method for the
accurate determination of the difference in longitude between
Paris. Bizerta (Tunis). Athens and possibly Lake Tchad.

MR. BARTRUM'S THIRD OUERV,— In my sohition
given last month, the full value of the constant k" should
have been given, as this varies with e and so alters the result.
Professor Adams showed that to get the numerical \alue of
the acceleration correctly it was necessary to introduce the
variation of e into the differential equations, and not merely
put in its rate of variation at the end. He in this way brought
down the numerical \-alue to about half what had been found
before. The publication of his result e.xcited a lively discus-
sion among mathematicians, and it was some time before
Adams' result won uni\'ersal acceptance.

STELLAR MOTION AND SPECTRAL TYPE. — The
study of the systematic motions of the stars has engrossed
much attention in recent years. Professor Kapteyn taking the
lead with his announcement of the two general drifts which
could be detected when the motions were analysed. This
announcement was confirmed and e.xtended by the work of
Mr. Eddington. Professor Schw.arzschild, and others. Last
year Mr. Hough and Dr. Halm examined the radial motions
of the stars, derived from spectroscopic observations, and
found that these too showed anomalies such as the two-
stream theory would lead us to expect. Dr. Halm has
recently (Month. Xot. R.A.S.. 1911. June) returned to the
subject and arranged the evidence in a manner which makes
the conclusions more evident. After eliminating the solar
motion he finds preponderance of motion in the direction of
the vertices of the two drifts. The average motion taken
without regard to sign is twenty-six kilometres per second in
these regions, and goes down to fifteen kilometres per second
at intermediate points. Dr. Halm's paper also contains
further confirmation of the result already announced by
Kapteyn and others that a star's velocity increases as its
spectral type grows more advanced. Thus the Orion type,
which is supposed to consist of very large and heavy stars, in

a \-ery early stage of de\elopment. has a mean motion of six
kilometres per second in the line of sight ; the Sirian type has
eleven kilometres, while for later types the mean motion goes
up to eighteen kilometres. The advantage of the spectroscopic
method is that it is independent of distance ; it is particularly
valuable in the case of the C~)rion stars, which are so remote
that their transverse velocity is difficult to ascertain.

Mr. Eddington. in a paper read before the British Association,
reprinted in the Observatory for October last, refers to the
above result as "one of the most startling in modern
astronomy." He proceeds: — "For the last forty years astro-
physicists have been studying the spectra and forming their
systems by which they arrange the stars in order of evolution.
. . . If this result is right we have a totally different
criterion by which the stars are arranged in the same order.
If it is really true that the mean motion of a class of stars
measures its progress along the path of evolution, we have a
new and most powerful aid to the understanding of the steps
of stellar de\elopnient,"

BROOKS' COMl'T, — This was a most conspicuous object
in the morning sky at the beginning of November, The tail
w-as plainly visible for 20° or more. Rev. T. E. R. Phillips
noted that its type appeared to have altered from the earlier
one of a bunch of straight rays diverging from the head, to a
parabolic envelope enclosing the head. There are good
reasons for supposing that this latter type arises for comets
when their distance from the Sun is small.

BORRELLY'S PERIODIC COMET will be visible in
small telescopes during December. An ephemeris is given in
"The Face of the Sky for January."

MARS has been a very brilliant object in Taurus, far out-
shining Aldebaran. the lucida of that constellation. From the
reports of MM. .-Vntoniadi and Jarry-Desloges it would appear
that veiling by mist or cloud of portions of the dusky regions
has taken place to an imusual degree at this opposition.

BOTANY.

By Professor F. Cavers, D.Sc. F,L.S,

STRUCTURE OF FLOWER IN CRUCIFERAE,—
Arising from the preceding note, there may be considered some
points in the morphology of the flower in the Cruciferae. The
peculiar structure of the Cruciferous flower has given rise to a
good deal of discussion, and the question is still open. As is
well known, the flower shows isobilateral symmetry. The
calyx is in two whorls, each consisting of two sepals ; the
corolla in one whorl, alternating with the calyx as a whole,
with the four petals placed diagonally in a cross. The stamens
are also regarded as being in two whorls, an outer whorl of
two short lateral stamens, and an inner of four stamens in
two pairs placed back and front. The pistil is apparently
composed of two carpels placed transversely (laterally) ; the
ovary is divided into two chambers by a partition joining the
two placentas, the latter being placed back and front — this
partition arises as an outgrowth of the placentas, the two out-
growths meeting in the middle of the ovary cavity ; the two
stigmas are placed above the placentas — a somewhat unusual
position (the stigmas usually alternate with the placentas) but
found also in the Poppy family (Papaveraceae). On the bases
of the stamens are nectaries, the honey being secreted into
the bases of the sepals.

From comparison witli the Papaveraceae, which have two
sepals, and from the fact that in development the four inner
stamens appear to arise in pairs by branching of an outgrowth
.it first simple in structure, it has been supposed that the

47S

December, 1911.

KNOWLEDGE.

479

Cruciferous flower is fundamentally arranged in twos — that it
is dimerous — and that the four petals and the four inner
stamens are due to branching. This explanation has been
widely accepted.

However. Klein (Bot. Cciiiralblatt, Band 58, 1894) has
urged that the Cruciferous flower is tetramerous — that is,
primarily arranged in fours, not in twos. He bases this ex-
planation chiefly on the position .and course of the vascular
bundles which supply the flower parts. Just below the flower
itself, the flower-stalU shows eight bundles arranged in an
ellipse. The first bundles to come off are at the ends of the
long axis of the ellipse, and they go into the two transversely-
placed sepals (though these are usually regarded as being the
outer and first-formed sepals): the bundles for the two median
(front and back) sepals come oft" higher up. Then, proceeding
upwards, come four strands which proceed diagonally (answer-
ing to the position of the four petals! ; each of these strands
soon branches into three veins, of which the median and
thickest one enters a petal, while the slender lateral ones go
into the neighbouring sepals — each sepal has, therefore, three
basal \eins (a thick middle vein and two slender lateral
veins). The veins for the two short stamens come oft' next ;
then four more veins running in the diagonal direction and
supplying the four long stamens.

From the arrangement of these veins, or vascular bundles,
Klein concludes that the long inner stamens are diagonal in
position, but have become approximated in pairs lying in the
median (back and front) line, simply on account of the
exigencies of space in the developing flower, due especially to
the position of the nectaries. Klein, therefore, opposes the view
that the four inner stamens have arisen by branching from two
primordia situated in the median plane. Further up, there are
two laterally placed veins, right and left, corresponding to the
position of the two chambers of the ovary ; and last of all
come two veins lying in the median plane, which run up into
the partition of the ovary. Klein regards these veins as
belonging to two carpels which cannot develop owing to
exigencies of space. Hence Klein considers that the flower
parts are arranged in fours, with the theoretical formula K4.
C4, A4 4- 4, G (4). The outer whorl of stamens is incomplete
on account of the development of nectaries in place of two of
the stamens ; the inner four stamens are arranged diagonally,
being opposite the petals ; and the two fully-developed carpels
alternate with two abortive carpels.

In further support of Klein's view, it may be mentioned that
in some Crucifers the four inner stamens are obviously diagonal,
rather than arranged in two pairs (anterior and posteriori ; also
that four carpels are present in genera like Hulargidiniit
and Tetraponuz. also in forms of Capsella. and in various
cultivated and wild varieties of other genera.

CHEMISTRY.

By C. AixswoRTH Mitchell. B.A. (Oxox.), F.I.C.

A STALAGMITIC GROWTH IN SEA WATER.— An
interesting case of the formation of mineral growths of a
stalagmitic nature is described by Mr. T. Walton, in the current
issue of the Joiini. Soc. Clieiu. hid. (1911. XXX. 1198).
These were produced in an iron tank through which sea water
had been flowing for several months for the purpose of cooling
ammonia heated by pressure in a refrigerator. At several
points in the pipe there were minute leaks, and the passage of
the ammonia through these caused precipitation of some of the
lime and magnesia in the sea water, and from the nucleus thus
deposited upon the surface of the coil small columns of white
mineral matter had gradually risen to the surface of the water.
These formations ranged in length from five to fourteen inches,
and from a quarter of an inch to three inches in diameter.
Examined under the microscope they were seen to ha\e a
cellular structure, which was due to the pressure of the
escaping bubbles of ammonia gas. The dried material
composing these " stalagmites "' consisted of eighty-eight per
cent, of magnesium hydroxide, eight per cent, of calcium
carbonate, 0-9 per cent, of calcium sulphate, and 2-S per cent,
of sodimn chloride.

ESTIMATION OF THE AGE OF BLOOD STAINS.—
.\ method of estimating the approxhnate age of blood stains
has been based by Dr. de Dominicis iBoll. Cliiiii. Farm.,
1911, L, 273) upon the rate at which they may be dissolved.
A small portion of the stain. il is immersed in pure

glycerine, and the tube given j . ^hake at intervals of a

minute until solution occurs. The yeiiow solution is protected
from the air and compared with solutions obtained in the
same way from blood stains of known age, the relationship
between the colour of which and the time required for the
solution is also known. It was found that blood stains which
dissohed within one minute were undoubtedly of recent origin,
while the longer the solution period the older the stain. The
presence of blood in the solution should, of course, be proved
by means of the spectroscope.

GEOLOGY.

By G. W. TVKRELL. A.R.C.Sc, F.G.S.

THE NEW GLASGOW MEMOIR.— In continuation of
the admirable policy of publishing maps and memoirs iflustrat-
ing the geology of large centres of population, the Geological
Survey has just issued a memoir and map of the Glasgow
district. These have been specially prepared, as we are told in the
preface, for economic and educational purposes with Glasgow
as the centre of interest. An official description of this
district was long overdue, for the old map (Sheet 30,
Scotland), published in 1878, was not accomp.anied by a
memoir.

As a centre for extraordinarily interesting and varied
geology, Glasgow is perhaps unrivalled in the British Islands.
Standing in a basin of Coal Measures and Carboniferous
Limestone which is highly fossiliferous and replete with
stratigraphical problems, it is surrounded, at a distance of
a few miles, by an almost continuous rim of high volcanic
hills, built up of igneous material of great variety and
petrographical interest. To the north, at a distance of twenty
miles, are the Highlands — an area of m\-ster\- likely to provide
Glasgow geologists w^ith work for many \-ears to come. To
the west the Clyde lochs and islands, including .Arran — that
favoured isle of perennial petrological interest — are easy of
access. Also within an easy distance is the comparatively
untouched area of Ayrshire, full of new material awaiting the
geologist's hammer.

Under these circumstances the new memoir is very welcome,
as providing a most valuable guide and groundwork to the
geolog>- of the district. The stratigraphical groups present in
the area described range from Lower Old Red Sandstone to the
Upper Barren Red Measures overlying the Coal Measures of
Lanarkshire. In Calciferous Sandstone times a great volcanic
episode occurred, w-hich gave rise to the fine terraced lava
escarpments of the Campsie and Kilpatrick Hills, flanked by
numerous isolated, conical, volcanic recks. Towards the end
of the Carboniferous period an interesting suite of teschenites
was intruded into the Coal Measures of the east of Glasgow.
Other rare igneous types are described, notably a bekinkinite
from Barshaw.near Paisley; and a beautiful porphyritic essexite
(long ago described by Allport) from Leimoxtown, both carrying
conspicuous nepheline. A good nepheline phonolite has also
been found near Fintry. The district is " full of petrographical
material of the first importance," says Mr. E. B. Bailey, who
has written the petrographical chapter ; and we concur with
his further remark that " the petrographical interest is likely
to quicken rather than flag as the igneous rocks of Ayrshire to
the west come to be examined."

A meritorious feature is the long chapter on economic
geology, giving information as to coals, ironstones, fireclays,
limestones and cements, setts and road-metal, building stones,
brick-making and water supply, a list which illustrates the
extent to which geology is a practical and applied science.

The colour-printed map is not so satisfactory as the memoir.
It is extremely complicated, and looks as if colour-printing
were being made to sustain an elaboration of detail of which
it is not capable.

4S0

KNOWLEDGE.

December. 1911.

METEOROLOGY.

By John A. Curtis. F.K.Met.Soc.

The weather of the week ended October 21st. as set out in
the Weekly Weather Report issued by the Meteorological
Office, was at first fair and very warm, but became unsettled,
with rains and thunderstorms. Temperature was very high in
all districts, and the excess above normal amounted in places
to over S°-0. and at Birr Castle to as much as 9°-l. The
highest readings reported were 68° at Guernsey, and 67° at
Jersey and Margate. The minimum was below freezing point
at only two stations. Balmoral 31°, and Nairn 30^. In the
English Channel the temperature did not fall below 52°. On
the grass readings of 26' at Ci'athes and at Glasgow were
reported. Rainfall was below the average in most parts, but
was in e.xcess in Scotland W., Ireland and in England. S.E.
.\t several places falls of upwards of an inch in twenty-four
hours were reported, the greatest being 1 • 7 inches at Brighton
on the 21st. Sunshine was less than average. The sunniest
stations were Jersey 25-4 hours {34%). and Gordon Castle
25-3 hours (35%). In Shetfield the total duration for the
week was only 1-2 hours (2%). The mean temperature of the
sea water round the coasts ranged from 46-0 at Kirkwall to
5S -1 at Newquay.

Aurora was seen at Fort William on the 17th.

The week ended October 2Sth, was unsettled throughout.-
There was much rain, some snow or sleet in Scotland and
many reports of thunderstorms. Temperature was in defect
in Scotland, but was not far from the average elsewhere.
The highest maxinuun was 62^ at Westminster, on the 22nd.
while minima of 32° or below were reported in all districts
except the English Channel, where the lowest reading was
45". The lowest of the minima were 21° at Fort Augustus
and Kilmarnock. On the grass temperature fell to 16° at
Llangammarch, and to 17° at Newton Rigg. Rainfall was less
than the average in Scotland, N. and W., but was in excess
elsewhere, very greatly so in the Channel Islands. Sunshine
was in defect except in Scotland N. and in Ireland, but except
in the extreme N. and extreme S.. the difference was not
large. Falmouth reported the largest aggregate, 28-4 hours
(41°i,l, Tenby coming next with 7-2 hours (39%). The mean
temperature of the sea water varied from 45 • 1 at Kirkwall to
57' -3 at New(iuay.

During the week ended November 4th, the weather
remained unsettled with freeiuent heavy rain. Thunderstorms
were reported in the North. Temperature differed but little
from the normal : the highest reading was 61° at Shields on the
30th, the lowest 15° at Balmoral on the 29th. On the grass,
however, the minima were as low as 8° at Llangammarch.
and 13° at Balmoral. Rainfall was in excess in all districts,
except England N.E. and the English Channel. In Scotland
it was from two to three times as much as usual. At Fort
.\ugustus the total for the week was 6-49 ins., as compared
with an average of 1-80 ins. Sunshine was in excess in the
Eastern districts, but in defect in the West. The aggregate
ranged from 31-1 hours (46%) at Felixstowe to 2-9 hours (5%)
at Baltasound and Fort Augustus. The temperature of the
sea water ranged from 42 at Kirkwall to 58° at Salcombe.

The week ended November 11th was also very unsettled.
There were frequent rains but also bright intervals. Thunder-
storms were observed over a wide area. Temperature was
below the a\erage nearly exerywhere, the difference from
average reaching 4-0 in Ireland. The highest maxinuun was
61° at Tottenham on the 5th. the lowest minimum being 2F at
West Linton on the 10th. In the English Channel the
temperature did not fall below 40 . On the grass the lowest
reading was 11' at Llangammarch.

Rainfall was in excess of the average in all districts except
England, N.E. In England, S.E., and the English Channel,
the total was more than twice the average. Bright sunshine
was above the normal in all districts, the greatest excesses being
in England, N.E., and the Midland Counties. Sheffield
reported the highest aggregate. 32-0 hours (51/'o). At Green-
wich the amount was 26-3 hours (41%). The temperature

of the sea water varied from 40' at Scarborough to 55
Newquay and Salcombe.

at

KITES IN THE UPP1;R AIR.— On October 21st a kite
flown at Pyrton Hill, Oxon, from 10 a.m. to 10.30 a.m.,
reached a height of 1,600 feet, and experienced a very strong
and gustv wind, during which the pull on the wire ranged from
10-lbs. to ISO-lbs.

GEOPHYSICAL JOURNAL.— The Meteorological Office
has commenced the issue of the Geophysical Journal, which
comprises not only Meteorological Observ.ations but also
the daily record of observations of Solar Radiation. Seismo-
logy, Atmospheric Electricity and Terrestrial Magnetism.
The contributing observatories are three in number, namely
Valencia. Co. Kerry; Kew. and Eskdalemuir, Dumfriesshire.
.A feature of the publication is the introduction of the
Centimetre-Gramme-Second System of Units for all the data.
Thus the barometer readings are given in " bars," i.e.
megadynes per square centimetre, where one " bar " is
approximately ecjnal to the pressure of 750 mm. of mercury :
temperatures are given in units on the Kelvin .Absolute Scale,
i.e.. in Centigrade degrees measured from a zero 273 below
the freezing point of water ; vapour pressure in " Millibars,"
and wind velocity in metres per second.

The Seisiitological data is for Eskdalenmir only, and is
based upon the records of a Galitzin Seismograph, giving
both period and amplitude of the microseisms. The Electrical
data provided for include the potential gradient, the number of
ions per c.c. and their velocity, the conductivity and the
strength of the air-earth current. The Magnetic data are very
full, and are based principally upon continuous automatic
records.

It is belie\ed that this is the first publication of its kind to
be issued in any country.

MICROSCOPY.

By A. W. Sheppard, F.R.M.S.,
xc'ith the assistance of the follotving niicroscopists : —

.\R1KVR C. Bankielu ARTHUR Earlanij, F.R.M.S.

The Rev. E. \V. Rowki.l, .M.A. Richard T. Lewis, F.R.M.S.

James Birton. Chas F. Roussei.et, F.R.M.S,

Charles H. Caffvn. D. I. ScoiREiEi.n. F.Z.S., F.R.M.S.

C. D. Soar, F.L.S.. F.R.M.S.

THE INFUSORIAN MICRON U CLE US IN
REGENERATION. — The behaviour of the infusorian
micronucleus in regeneration was dealt with by K. R.
Lewin, B..\., in a paper read before the Royal Society, on
November 2nd.

The variety of Sfylonrchia niytiliis used was that
possessing two micronuclei, and when a specimen is cut in
two so that each merozoon receives one member of the
meganucleus and one micronucleus, both fragments exhibit
in favourable circumstances complete regeneration. This
involves segmentation of the meganuclear member, and
division of the micronucleus.

If a portion of the cytoplasm be removed from the hind
end of the animal without disturbing the nuclei, there may
occur during regeneration a division of one. usually the
posterior, micronucleus. The result is to furnish the
regenerated infusorian with three micronuclei instead of two.
i.e., the division does not restore but actually disturbs the
nuclear relations characteristic of the race. When the
regenerated individual proceeds to fission, all three micro-
nuclei divide. That an extra division can be introduced into
the normal cycle of mitoses shows that the organella is in a
fit state to divide before the whole animal is ready for
spontaneous fission ; that the supernumerary mitosis occurs
during regeneration suggests that the stimulus causing the
micronucleus to divide may be the condition of the
surrounding cytoplasm which obtains during the constructive
activities of regeneration.

The cases in which regeneration occurs without either of
the micronuclei dividing can be supposed to be those in

Deckmber, 1911.

KNOWLEDGE.

481

Figure 1.

which either the micronuclei were not ripe for mitosis, or the
stimulus was not sufficiently intense to evoUe a division.

Durint; normal fission when all the micronuclei present
divide, there is a general formation of new parts, quite
comparable with the localised acti%ity in regeneration and
accompanied, it is natural to suppose, with much the same
condition of the cytoplasm. The mitoses occurring normally
and those taking place during regeneration, can thus be
brought under one point of view.

EUGLEN A EHR. — .Although such a " connnon object"
as sometimes to be quite an inconvenience to the microscopist,
Euglcna viridis (Figure 1) has many points of interest which
will repay rather more attention than is usually accorded to
them. As with not a few other micro-organisms, in the past
there has been much dis-
cussion as to whether it
should be classed as an
animal or as a plant.
The modern view is that
it partakes of the nature
of both and may best be ;■
described as a plant- L '
animal. Its possession of ' K,
a mouth, and the ingestion
of solid food, and its
general activity entitle it
to be looked upon as an
animal ; while its green
colour, which is undoubt-
edly due to the presence
of chlorophyll of the
same character with that
of plants, and the fact
that it appears possible
for it to exist without taking in food by the mouth, endorse its
claims to be considered as belonging to the vegetable kingdom.
Recently a small book under the name of '' Flant-animals,
a study in symbiosis " was published, describing two small
worms (Convoluta) which display the same characteristics
in a marked degree. The facts ascertained respecting
these and the exhaustive experiments made on them
prove conclusively that there are aquatic organisms,
which, though unquestionably animals, yet owing to the
inclusion of chlorophyll within tliem are able to, and
actually do, obtain the carbon elements of their food, at least
during a portion of their life, from the carbon dioxide
dissolved in the water. The extent to which this capacity is
possessed and exercised differs in various cases, but Eiiglena
viridis certainly takes advantage of its endowment in this
respect and so may be looked upon as a plant-animal. It has
been suggested that the creature takes in nourishment during
daylight as a plant by means of its chlorophyll, during the
darkness feeding as an animal, but perhaps this idea rather
exaggerates its voracity. It is not possible to make oat the
mouth and flagellum while the animal is swimming, but the
careful application of a little iodine will kill it and bring them
into view. The mouth is a funnel-shaped depression in the
forward end — only capable of receiving very small particles —
and from it springs the long, and during active life, swiftly
moving flagellum (Figure 2a). The body is covered with a
delicate cuticle, not sufficiently firm to prevent it readily
changing shape; that represented at Figure 2b, is frequently
assumed. The protoplasm is granular and the chlorophyll
seems to be diffused in it, not collected into definite " chloro-
plasts." Many partially transparent bodies of considerable
size are usually present ; they resemble starch grains, but the
substance composing them is known as paraiuyhini. and
though having the same chemical composition as starch, is
not coloured blue by iodine. A nucleus is present and near
the usually distinct red '' eye spot " a contractile vacuole.
For the purpose of multiplication, towards autumn, or at any
time on the occurrence of unfavourable conditions. Englciia
may assume the encysted state. The body becomes spherical
and a wall of cellulose tjeffery Parker) is secreted round it. If
the animals are present in great numbers — as is frequently

Figure 2.

the case — they adhere and form a kind of pellicle on
the surface of the water. Blown by the wind, or
moved by any object, this does not readily break up, but
will crease and fold, just as the scum on boiling milk does.
Later the animals may resume their active state, and the
cells which contained them (at first circular, but aftervv.ards,
owing to pressure and mo\ement, angular and mis-shapeni are
left adhering together, and have exactly the appearance of a
cellular membrane (Figure 1). This persists for some time,
and various floating a<iuatic organisms make it their home. It
has been mistaken for, and described as, some kind of alga.
During the past summer this object has often been noticeable
on the surface of ponds as a brownish delicate film. While
resting encysted the individuals may undergo division into
two or four smaller specimens, but of the same shape as the

adults, so that on emer-
gence their numbers are
greatly increased. Figure
2c, "An interesting local
variety of Eiiglena
I'iridis. has been des-
cribed by Mr. M. H.
Robson, of Newcastle-
on-Tyne. in Science
Gossip, October. 1879,
in which the distal ex-
tremity of the flagellum
piesents an inflated knob-
ike aspect." Figure 2d :
The same singular variety
has recently been recog-
nised in some ponds near
London.

Figure 1 is from a
specimen which lasted
several weeks in a saucer of water after being brought from
a pond. The membrane is represented on the same scale as
the two animals above. Figure 2 is from Saville Kent's
Infusoria, a and c highly magnified. , u,..,-,. ,,.

AMPHIDINIUM OPERCULATVM CLAP AND
LACH. — In the Journal of the Linnean Society, \ol. XXXII,
pages 71-75, Professor W. A. Herdman, F.R.S.. describes the
occurrence of this little peridinian in vast quantities in Port
Erin Bay (Isle of Man). The hollows of the ripple-marks and
other slight depressions formed by the water draining off the
beach were occupied and outlined by a greenish-brown deposit
which in places extended on to the level, so as to discolour
patches of the sand. Here the deposit remained more or less
for a month, waxing and waning, sometimes increasing in the
tide, say, roughly ten-fold, and at other times apparently
disappearing for a day or two and then reappearing either on
the same part of the beach, or it might be a few hundred
yards away. At one time it coloured a continuous stretch of
sand about fifty yards long by five yards in breadth just below
high-water mark, and was noticeable for some distance away.
On examination the deposit was found to consist of vast
numbers of A. opcrciilatnni. This peridinian was first
described bv Claparede and Lachmann. in 1858. from
specimens obtained in some few places in Norway, and
according to a recent authority is found occurring in brackish
water on the North Coast of Europe, but has not been
previously recorded for the British area. It was first
obser\ed at Port Erin early in the year, but later brown
patches of similar appearance were again observed on the
sand ; on examination these were found to consist of vast
numbers of a golden-yellow naviculoid Diatom. The
Amphidinium had disappeared, but re-appeared in abundance
by September.

Under observation A. opcrciilatnni swims about freely,
but soon comes to rest by attaching itself to a sand-grain. It
is positively heliotropic and collects in quantity on that side of
the dish which is turned towards the light. Multiplication b>-
fission was frequently observed. Its greatest diameter is
0-()5 millimetres.

482

KNOWLEDGE.

December, 1911.

OUEKETT MICROSCOPICAL CLUB.— October 24th.—
Professsor E. .\. Minchin. M.A.. F'.R.S.. President, in the
chair. .\n old microscope, sent by Mr. Hugh Paterson. of
Sydney. N.S.W.. was exhibited. It had been presented,
abont 1850. to his father, by J. T. QneUett. F.K.S. (1,S15-61I.
the distinguished niicroscopist. after whom the club is named.

E. M. Nelson, F.R.M.S. — " .An improved compound iiiicro-
scope. by James Mann, 1751,'' was read by the Hon. Sec.
The instrument is. in the main, obviously a copy of J. Cuffs
(17441. the improvements consisting in the mirror and its
attachment, and in making the instrument portable. The
first portable compound microscope was made by George
Adams, in 1746. and the one now described showed Mann's
device for adapting .Adams's idea of portability to Cuff's
microscope. Very probably this was the second portable
microscope.

J. W. Shoebotham, N.D.,A. — " .'A general account of the
Spring-tails iCollembola)." They were described as belonging,
with the orders Protura and Thysanura, to the sub-class
Apterygota. of the class Insecta. The anatomy of the Col-
lembola was described fully, accounts being given of the eyes,
post-antennal organ, pseudocelli, antennal organs, body, legs,
and those very typical and curious organs, the ventral tube
and the spring. .A tracheal system is usually absent and in
the few species possessing one it is very poorly developed.
Although they have generally been regarded merely as
scavengers, there is now evidence to show that they may
do considerable damage to growing crops. Between four
hundred and iive hundred species are at present known, of
which one-hundred-and-seven have been recorded from
Britain.

Messrs. Watson & Sons exhibited under microscopes an
interesting series of preparations of embryos of Decapods.

THE ROYAL MICROSCOPICAL SOCIETY.— October
ISth.— H. G. Plimmer, F.R.S., President, in the chair. —
T. W. Butcher: Structural details of Cosciiwdiscns aster-
oinpltalits. A paper describing the primary areolations with
the secondary and tertiary markings, illustrated by a series of
lantern slides made from photomicrographs obtained at a
magnification of one thousand one hundred. In addition
slides were shown demonstrating a fine siliceous network or
veil lying upon the outer surface of the valve, and others in
series, from photomicrographs taken, at five or six consecutive
foci, of the hexagonal cell layer with its " ringed " openings of
Morland, to prove that these openings are clear and not
obstructed by the finely perforated membrane recently
reported by Mr. Nelson ijourn. R.M.S.. October 1910). The
membrane being non-existent, its value as a test for a high-
power lens is nil. — Rev. Hilderic Friend: New British
Enchytraeids. Encliytraeits niiiiiinus Bret, was described in
the Rev. Suisse de Zoologie in 1S99. Michaelsen, in Das
Tierreicli, 1900, suggested that it might be one with
E. argenteus Mich. (= E. parvulus Friend). Bretscher
examined the subject again in 1902. and decided that the
two were distinct. The author, who had already described
E. argenteus. has found E. minimus at Buxton, and
holds with Bretscher. Fridericia peruviana n. sp. was
received in earth from Peru and submitted to the
author by the authorities at Kew. It is 5-6 nun. in
length, has 2-5 setae which are somewhat larger behind
than before. Brain slightly concave posteriorly : oeso-
phagus sharply marked off from intestine : dorsal vessel
postclitellian in origin with dilatations in segs. 7-9. Salivary
glands not branched; long. — Walter Bagshaw : Instantaneous
exposure in photomicrography. — Flashlight illumination has
been put to a novel use by Mr. Walter Bagshaw. F.R.M.S.,
for the photography through the microscope of objects in
motion. A good negative of freshwater poly^^oa, iLophopns
crystalliniis) expanding its tentacles, was secured by a
charge of "Agfa Flashlight Powder" in one-thirtieth of a
second. Gatherings of Pond-life, such as diatoms, larvae,
water fleas, also yielded successful results. Provision was
made for replacing the ordinary lamp by flash powder put in
the position previously occupied by the centre of flame, .and
ignition made with a red-hot wire.

ORNITHOLOGY.

By Hi'Gn Bovi) Watt, M.B.O.U.

BLACK REDSTART REPORTED NESTING IN
ENGLAND.— It is stated that the Black Redst.art (Rnticilla
titys^ has been identified as nesting in the Keswick district
this season (1911). Very conclusive and convincing evidence
is. however, necessary before this species can be admitted to
the list of British nesting birds. In past years supposed eggs
have been obtained or observations made in different localities
(Sherwood Forest, in 1854 and 1856; Dumfriesshire in
1858 and 1SS9. and Hertfordshire in 1876). but in no case has
the identification as to nesting been accepted as satisfactory.
The bird's habitat is central and southern Europe, and the
seasons of its annual occurrence in England are autumn and
winter, although in a very few instances it has been found at
other times. This distribution is rather curious, as it is
only a summer visitor in central Europe, and has not so high
a northern range as the Common Redstart (R. phoenicnrus),
which appears throughout all Europe in summer, and is not
known in the British Isles at any other season of the year.
The point is. that the summer Redstart in Britain is the more
northern species, but the visitant Redstart seen i[i autumn
and winter is the southern form (/?. fitys).

THE STARLING AS A MIMIC— A correspondent,
Mr. Basil T, Rowsfell. writing from St. Martin's. Guernsey,
says that on 22nd September last he was astonished to hear
what was apparently a Wryneck's call from a tree in his
garden there, clear and distinct, as it may be heard in spring
and early summer. This was repeated for some days up to
6th October, and, by carefully watching. Mr. Rowsfell made
out that the calls came from a Starling {Stnrntis luilgaris).
He suggests that this particular bird may have been reared in
the immediate vicinity of a Wryneck's nest, and caught the
note from the parent Wrynecks.

Starlings are, of course, well known as mimics. The wailing
whistle of the Common Curlew (the Whaup of northern
districts) is associated with wild and lonely places, but we
have known a Starling to give a very passable i[nitation of this
call from the house-tops of a great city. This individual bird,
or another which had also picked up the trick, returned to
the same place a second winter and brought moorland echoes
with it. amongst thronging people and crowded houses.

THE NATIONAL COLLECTION AT SOUTH
KENSINGTON. — According to the "Return" presented to
Parliament of the British Museum for the year 1910, the
additions made to the great bird collections at the Natural
History Museum amounted to 9377 specimens in the year
named. These came mostly from Asia, .Africa and South
America, and several of the collections consist of some hundreds
of items. The most extensive is 1346 birds, nests and eggs
from .Angola. Portuguese Guinea, and the Cape Verde Islands,
obtained by Dr. W. J. Ansorge.

IMlOTOGK.Al'HY.

By Edgar Se.mor.

The article in " Notes" of last issue contained a description
of the use of a pin-hole in place of a lens, and was illustrated
by an excellent photograph taken by its means. It may,
therefore, be of interest in connection with this subject, to
just consider "on theoretical grounds." the conditions which
govern the use of plain apertures, in order to obtain the best
results with them in practice. It is well known that
photographs taken by means of a plain aperture in place of
a lens, pos.sess advantages over those taken with the lens,
in .so far .as distortion is entirely absent, and the artistic effect
obtained is extremely pleasing. It is also well known that for
a given aperture an image will be obtained at whatever be the
distance from it to the plate ; but it was proved many years
ago by Lord Rayleigh. as a consequence of the Wave Theory

December, 1911.

KNOWLEDGE.

483

of Light, that the best definition is obtained when the
diameter D of the aperture is related to the distance L
from it to the plate, as given by the equation

D = 2 \/^ L

where \ is the wave length of the light employed.

Taking into account the wave length of light of maximum
photographic activity. Sir W'illiam Abney gives the formulae

D

iVl

120

where D and L are measured in inches. It was proved by
Lord Rayleigh that when the conditions specified by his
formulae are complied with, no further improvement could be
obtained. We have before us as we write a photograph
taken by means of a plain aperture, in which the conditions
set forth above were fulfilled The distance of the plate was

nine inches, and from our formulae D =t:^ ^^"^ obtam

ITS inch as the diameter of the aperture that w^ould give the
best definition with the plate placed at nine inches from it.

COLOUR PHOTOGK.APHV UPON PAPER.— However
beautiful may be the colour photographs in the form of
transparencies upon glass, there is still the feeling among a
large number of persons that the only really satisfactory
solution of the problem of photography in colours will be
found in a process which is applicable to paper. Quite
recently the attention of photographers has been drawn to a
new paper which has been placed upon the market for the
purpose: prepared by Dr. J. H. Smith. The general principle
upon which several experimentalists appear to be working is
that suggested by Wiener, who considered that the chromo-
sensitive surface should be black, and composed of, at least,
three physical elements. The writer experimented in this
direction some few years ago, employing paper coated with red,
yellow and blue dyes. The dyes being fugitive, the prepared
paper was found, after exposure under a coloured transparency.
to give a fairly good rendering of the object, although in every
case the time necessary to obtain the results was \ery pro-
longed, amounting to days in the strongest light. To what
extent this and other difficulties may have been removed we
are unable to say, as we ha\e not had an opportunity of trying
any of the recently prepared papers.

PHYSICS.

By Alfred C. G. Egertox, B.Sc.

POSITIVE IONS FROM HOT SUBSTANCES.— These
have been the subject of numerous investigations recently.
Professor Sir Joseph Thomson found that aluminium phos-
phate gave off a large number of positively-charged particles
when deposited on a platinum strip which was heated to about
lOOO'C. Garrett and also Horton have investigated the effect
and have shown that the production of these positively
charged ions is intimately associated with the production of
small quantities of carbon monoxide — a very commonly
occurring substance in vacuum tubes submitted to the electric
discharge.

Professor Richardson has investigated the carriers of
positive electricity from strips of platinum coated with
alkalis and alkaline earth metals. He finds evidence to show-
that these carriers are atoms of the metal carrying a single
charge. Even the divalent metals carry only a single
positive charge, which is contrary to what might be expected,
since these metals are chemically equi\alent to two atoms
of hydrogen. The heated platinum itself gives off a certain
number of charged ions and Professor Richardson has in-
vestigated this thoroughly. He suggests that the considerable
discharge of positive particles from aluminium phosphate is
due to the impurity of alkah metals it contains. These
positive ion discharges are not nearly so marked in effect as
the negatively charged particles emitted by the alkaline earth

oxides. If a small piece of sealing wax be allowed to coat a
platinum strip mounted in a vacuum tube so that an electric
current can be passed through it, and if there is a difference
of potential of 100 volts or thereabouts, between the strip and
another electrode in the tube, then on heating the wax. only
lime and barium oxide is left which causes a copious discharge
of negative corpuscles. Professor J. J. Thomson has utilised
these discharges to obtain steady striations in a vacuum tube
and by investigating the behaviour of a cathode ray beam
from a side tube as it passes transversely through the electric
field in various portions of the striated discharge, he has been
able to find the magnitude of this electric field, and hence
show that the striations are due to the crowding up of
corpuscles. The collisions of these with the ions of the gas
cause the latter to radiate light. From these areas of
collision corpuscles acquiring great velocity are shot off in the
direction of the positive electrode and until, by collision with
the gas molecules in the tube, their velocity is reduced to such
an extent that they can no longer keep on in a straight path,
there exists a dark space. Thus a striated discharge comes
about ; the number of striations depending on the pressure of
the gas in the vacuum tube.

\\"hen an electric discharge is passed through a gas at low
pressure, it has long been questioned whether the gas is
electrolysed ; that is, suppose one passed an electric discharge
through hydrochloric acid gas, would hydrogen be found in
greater concentration at the cathode and chlorine at the
anode, as in the electrolysis of the aqueous acid. Professor
Thomson many years ago succeeded in obtaining the hydrogen
spectrum at the cathode and the chlorine at the anode and on
reversing the current the hydrogen and chlorine changed
places, the hydrogen still being found at the cathode. How-
ever Kayser, the illustrious author of the " Handbuch der
Spectroskopie," has asserted that these effects are due to
thermal effects, the cathode being always hotter than the
anode. Recent experiments at the Cavendish laboratory have
apparently shown without doubt that a separation of an
electrolytic nature does occur, but that the effect is upset by
the mobility of the gaseous ions and consequently thermal
effects come in to a great extent. Many organic halogen
compounds have been investigated, and the chlorine is some-
times found at the anode and sometimes at the cathode, but
as a rule e.xactl}- in accordance with its chemical behaviour,
either as an anion or cation. In a compound such as methyl
sulphide, sulphur would be found at the anode and the carbon
monoxide spectrum at the cathode. These results have been
obtained by Mr. G. Stead.

ZOOLOGY.

By Professor J. Arthur Thomson, M.A.

ASSOCIATION OF CRAB AND HYDROID.— Everyone
knows that many animals grow upon others in an accidental
sort of way, because the young stages landed there. This is a
fortuitous epizoic association. Sometimes, however, the
association, though remaining entirely external, is by no means
fortuitous ; thus many spider-crabs pluck hydroids along with
sea-weeds from their surroundings, and plant them on their
shells, with the result that they are "masked." Different from
this again is a case like the following, recently described by
Dr. W. T. Caiman, whose delightful introduction to Crustaceans
('"The Life of Crustacea," Methuen. 1911) should be read by
all interested in Natural History. A crab from Christmas
Island showed a hydroid polyp, allied to Stylactis, attached
like a tassel at the "knee" of each of its legs. This is
interesting in several ways. All but two of the polyps were
svmmetrically disposed ; the type specimens of the species
iMcdacu^ has-ii-elli) to which the crab belongs, although
coming from a distant locality, were found to bear a similar or
identical hvdroids: the crab is a Xanthid. not one of the spider-
crabs in which masking is common ; even the rootwork or
hydrorhiza was very precise in its occurrence, following the
inter-regional grooves on the carapace.

^84

KNOWLEDGE

Dkchmber, lyil.

A PRIMITIVE ANT SOCIETY.— There isaMediterraneau
ant, Aphacnogasfer sardoa by name, not uncommon in
Sardinia, which illustrates a simple type of societary form. —
simple, at least, as ant-societies t;o. It has been recently
studied by Dr. Krause-Heldrungen. who describes the way in
which the ants huddle together in living balls, interlocked with
mandibles and tarsi, and holding the eggs, larvae, and pupae
in the centre, kw average society consists of three hundred
to a thousand individuals ; the males have not been found :
and the observer found only one queen. .Architectural con-
struction is at a minimum : they use holes in the ground.
They do not store and they have no guests. Huddling
together in a ball is their form of sociality. In winter the
ball is very stiff and is slow to rela.x when it is unearthed.
In summer, naturally, it is more plastic, being made a?id un-
made several times .i day.

BL(JOD-SL'CKING .MAGGOTS. — There is a fly called
Auchmcroiiiyiit Intcola (Eabr.l, whose larvae have the
remarkable habit of piercing the human skin and sucking
blood. This has been hitherto a quite unique thing, but
E. Koubaud has found its parallel in a related .African form,
for which he establishes a new genus Choeroiuyia. One
species lives in the burrows of the Cape .Ant-Eater and
another along with the Wart-hog. The flies eat dung and like
darkness. The larvae live in the damp ground ; they are able
to fast for a long time : they are attracted to the warmth of

their hosts ; they fix themselves on the skin, pierce it, and suck
blood. They can ingest three times their weight of blood,
Koubaud reared one on himself.

BEETLES IN NESTS.— Heinrich Bickhardt has collected
the available information in regard to what he calls " nidi-
colous " beetles — those which live in the nests of birds and
mammals. There are no fewer than twenty-eight which are
found exclusively in nests. A much longer list is given of those
that usually occur in nests, but also in other suitable places
Besides these there are casual visitors. Of the e.xclusively
nidicolous beetles, eighteen are confined to the homes of
Mammals, such as mole, hamster, mouse and rabbit : seven
are confined to the nests of birds, such as dove, sand-martin,
owl, and woodpecker : three are found associated with both
birds and mammals.

INNERVATION OF WINGS IN LEPIDOPTERA.—
R. Vogel has made a study of the rich innervation of the
wings in butterflies and moths, and shows how rich the wings
are in sensory structures. There are tactile scales and
(probably) tactile spines. There are peculiar papillae, which
may have to do with orientation in flight, and " chordotonal
organs " like those which distinguish notes in various
Orthoptera. .Altogether the wing is an exquisitely sensitive
structure.

SOLAR DISTURBANCES DURING OCTOBER, 191 1

Bv ER.\XK C. DENNETT.

The falling oft' in solar disturbance shown last month was
equally noticeable during October. Observations were made
on twenty-nine days, the omissions being on the 16th and 27th.
On fourteen days the disc presented an even brilliance, save
for the delicate granulation, these being October the 9th. 10th,
13th until 15th, 17th until 21st. 24th. 2rith. and 28th until 31st.
On the 1st and all other dates after the Kith only faculic dis-
turbances were seen. The central meridian on October 1st
was 289° 42'.

No. 37. — Two brilliant cur\ed ridges of f.iculic matter
formed a striking object a little within the eastern limb of the
Sun on October 1st, like the borders of an elliptical disturb-
ance. On the 2nd in place of the western ridge a dark spot
having two umbrae had developed, whilst three pores were
embedded in the eastern ridge. Next morning the spot had
become 10.000 miles in diameter, and the number of pores had
reached seven, the group being 30,000 miles in length. Only
two of the pores were seen following the leader on the 4th.
By the 6th the leader enclosed two umbrae, whilst one pore
showed 10.000 miles behind and a second nearly two degrees
south of the leader. On the Sth the leader, reduced to a pair of
umbrae, was alone, and had quite disappeared before next
morning. The spectroscope showed a considerable amount of
activity around this group indicated by dark hydrogen flocculi

extending for a long distance. On the 6th there was a consider-
able prominence visible, projected on the bright surface, a little
south-east of the spot, whilst the whole region showed traces
of helium by the presence of the dark line known as D:i.

The dotted areas indicate the positions of faculic
disturbances. On October 2nd a small bright knot was
visible near longitude 353°, S. latitude 17°. On the Sth
there was a small knot at 269°, N. latitude 5 . On the 11th
and 12th two separate faculic disturbances were visible near
the western limb, one double group closely ahead of the place
where the spot group. No. 37, had disappeared, whilst the
other was on the other side of the equator. On the 22nd and
23rd there was a faculic district about longitude 10°, and 10°
N. latitude. On the 25th there was a group of greyish pores
in a disturbed area near longitude 2S0°, but careful measures
were not possible.

The Prominences are much fewer in number than was the
case only a few months since. The most remarkable one
appears to be a very tall spindle at 20 South-east, seen on
October 21st.

Our chart is constructed from the combined obserxations of
Messrs. John McHarg. ,\. A. Buss. E. I". I'eacock and
F. C. Dennett.

n.AY OF OCTOBER, iqii.

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W X 'J! 'i bO' TtS 80' W lOO' 110' li'ff IM I4(r I5(f 160' 170' 180' 190' aiO' lid HS ZiO' 240 25|J 1^ ZTS 2S0' SOT 300" M' 320 35tf M' 350' 5«'

REVIEWS.

EVOLUTION'.

Convergence in Evolution. — By Dr. Arthur Wili.ev,
D.Sc, F.R.S. 177 pages. 12 illustnitions. 8f -in. X 5A-in.

ijohn MuriMv. Price 7 6 net. I

Dr. Willey writes, he says, so as to be intelligible to those
who have an inkling of biological knowledge, bnt it is
probable that his argument as a whole will hardly be
appreciated save by trained zoologists. Nevertheless, there
is an abundance of facts recorded, many of them new and all
interesting, that should appeal to every naturalist however
much of an amateur he may be : and it is safe to say that
even a professional zoologist will learn much to his advantage.
The author sets out by reviewing certain points in the grouth
of the science of morphology and its kindred brunches which
have rendered them valuable both as intellectual recreations
and as of direct practical use to mankind. He goes on to
suggest ihat we may look to other properties of animals
besides those of structure to gain a comprehensive survey of
the animal kingdom. Without going so far as to compare the
value ot classification based on structure with that based on
similarity of function, he asserts that too little attention has
been paid to what may be called physiological systems of
classification. .\ir breathers, and water breathers, fixed
forms (statozoa) and free forms (eleutherozoa), light avoiding
habits (cryptotaxisl. and light seeking habits (phanerotaxis),
and so on. are compared together, with a host of interesting
and illustrative facts of natural history, many of them
personally observed by the author. Similar habits and
environment have brought about similar structure : in other
words, convergence and parallelism have been far more potent
factors in evolution than is generally believed, and the same
structure in homogenous animals has nevertheless often
been independently acquired. Especially applicable are
his ideas of convergence, divergence and parallelism to
the parallel series of marsupials and placentals : perhaps
the most convincing arguuient in the book. According
to Dr. Willey, convergence may be traced in the anatomy,
bionomy, physiology and histology of animals closely
related and widely dissimilar, e.g., the pectoral fins of
flying fishes, and the solenocytes of .\mphioxus and the
Polychaetes, to take but two examples. He might also have
added psychology as well. Nothing is clearer from the results
of anthropological research, than that the dift'crent races of
men. separated by the whole length of the globe, have evolved
•almost, if not quite, the same myths and folk-lore, indepen-
dently of one another.

Nevertheless it must be confessed that the ordinary zoologist
will not feel that his cherished beliefs and traditions have been
seriously undermined by Dr. Willey"s book. The true test of
relationship of animals must be based on the structure of
modern and extinct forms, and this fact Dr. Willey would
himself probably be nuwilliug to challenge; and although such
eminent writers as Dr. Gaskell, whose theories as to vertebrate
origin the author extensively quotes to refute, may be led into
situations where the finding of homologies based on structural
resemblance takes on an almost terrifying aspect, yet the
main principle holds good.

Here and there, e.g.. on page 10, it is not easy (juite to
understand what is meant, but. as a whole, the book is clearly
and brightly written. \r n H

Neglected Factors in Evolution. — Hy H. M. Bernard.
489 pages. 47 illustrations. Sj-in. X 5n-in.

(G. Putnam's Sons. Price 12, 6 net.)

It not infretjuently happens, and this book is a case in
point, that a biologist after years of work in some more or
less restricted branch of his subject, it hardly matters what,
proceeds to the most far-reaching generalisations. We are

far from deploring this tendency, though at times it is
accompanied by a want of sense of proportion, patent to all
save the author himself. For it is an undoubted fact that
careful observations even of a limited scope, coupled with
sound reasoning and a sufficient dose of imagination, have in
the past, as they will in the future, ^ • ■■^•onized biological
science. We leave our readers t^ i a- themselves if

this is true of Mr. Bernard's work. i .i author is chiefly
known for his researches on the histology of the retina, and on
the morphology of the apodidae and of other arthropods.

The book is divided into two parts. The first, however
much we may disagree with the conclusions therein arrived
at, is a valuable contribution to cytology. It is clearly
written throughout, and Mr. Bernard never forgets the point
of view which most biologists hold on the Cell Theory. That
the facts observed necessarily prove the theory does not
follow, though there is much to be said in support of it.
yet the author's careful summary of the facts in itself
is a valuable piece of work. .\ long study of the minute
structure of the human retina convinced him that the
views commonly held as to the fundamental nature of
tissues in general are untenable. In common with Whitman,
Sedgwick, and others, he refuses to look on cells as the lowest
units of life. The structure of bacteria and of some protozoa,
and the histology of the metazoa prove, he thinks, that
organisms are not made up of cells but of smaller units, which
he calls chromidia. A cell is simply a complicated tangle of
chromidia. and cell-boundaries are always indefinite and of
little importance. In fact protoplasm is made up of a
network of living threads, visible only when they are coated
with some stain-receiving matter, on which are threaded
lumps of chromatin. This latter substance he believes to be
chiefly made of complex chemical bodies necessary for
the life of the filaments. A simple chromidium consists of a
small lump of chrouratin provided with a number of radiating
threads along which it can creep backwards and forwards,
bathed in a nutritive albuminous matrix. He points out that
such a view of cell structure brings into harmony the well-
known views of Butschli and Altmann as to the structure of
protoplasm ; with great ingenuity he applies this conception to
explain not only the structure of a typical cell, but qf cilia,
flagella, ecto- and endo-plastic skeletons, and even the
phenomena of mitosis. Though in justice to the author
it should be remarked that few difficulties are shelved, yet
more attention should have been paid to the discoveries of the
"' EIntwickelungsmechaniker.'' The fact that isolated blasto-
meres of developing eggs can produce a perfect though much
reduced larvae hardly squares with his theory. Mr. Bernard
believes that the cell theory in its present shape stands in the
path of further progress in cytology, while his theory of a
primitive network, protomitome. pervading the whole organism,
certainly does away with some of the difficulties attending a
comprehensive understanding of tissue formation. Further-
more, we are shewn the way in which the metazoa might have
been evolved from an unicellular ancestor. .'\11 this is very
interesting, and, if not convincing, is at all events well worth
reading.

Part 2 contains far more theory and less fact. Postulating
a kind of rhythm -in evolution, the author sug.gests that the
factors according to Darwin are insufficient to explain the
gradual development of a highly dift'erentiated organism such
as Man. He believes that evolution has been marked by
periods at the end of each of which an outburst of activity
has taken place resulting in colony formation. A colony
of chromidial units becomes a cell, a colony of cell units
becomes a gastrael unit, a colony of gastrael units
forms an annelidan unit. Some such creature as an annelid
gave rise in the process of evolution to vertebrates, culminat-
ing in Man himself. The fifth evolutionary colony formation
has Man as its unit, the colony itself being human societies.
Just as the physical bodies of all the five units consist of a

485

485

KNOWLEDGE.

December, 1911.

network, so are the units of human societies joined together by
a psychical network, invisible perhaps, but connecting man to
man. The physical network that exists between a mother and
her unborn child is broken at birth, but a psychical network
connects them both until death, and perhaps hereafter.
Thought transference is taken for granted as an established
fact : and it is hinted that in another stage of existence, or
possibly in this, more and greater bursts of evolutionary
actixity may be in store for the human race.

In conclusion, we may cordialK' recommend I'art 1 to the
notice of biologists, even if

they do not agree with Mr. i-^^— -,-. ■,.■-. — ^ m^.,,
Bernard's views. As to
Part 2 it is harder to speak.
We ourselves believe that
the time is not yet ripe for
such speculations, and
although most biologists will taMaB^i.
pause to think from time to
time over such matters as
the connection of the physi-
cal with the psychical,
materialism and vitalism,
and kindred speculations,
which the study of living
matter arouses, it does not
necessarily follow that much
will be gained by giving
them to the world at large.

M. D. H.

77(1' Evolution of Paint-
ing: A History of J^aint-
ing in Italy. — Hy J. A.
Ckowi; .and G. B. Cavai-
CASHi.i.E. Vol. IV. 379
pages. 54 illustrations.
9-in.X6-in.

Ijolni Murray. Price .21
net.)

It is with the greatest
satisfaction that e \ e r \-
student of painting, as well
as those who are interested
in art for its own sake, will
receive the intimation from
Mr. John Murray that tlie
re-issue of Crowe and
Cavalcaselle"s great work is
now on its way to a satisfac-
tory completion. When
Mr. Crowe and Signor
Cavalcaselle wrote their
volmnes.the study of Italian
painting was the privilege
of a few, and the occupation /'wv
of a yet more limited band
of enthusiasts ; the photo-
graph and the cheap trip
were alike remote. But the genius, the industry, and the
visual memory of these two men were capable of pro-
(lucing a treatise on the subject such as remains an
unassailable masterpiece ; and though the books on Italian
Masters are almost as nmnerous as the picture post cards
which the twentieth century tourist in Italy brings or sends
home as mementoes of the paintings he has seen, none of them
has the unique authority and comprehensiveness wliich this
work attained. Nevertheless, the demand for information
must evoke a supply, even of pictures and the whereabouts of
pictures. One might almost go so far as to say that the
demand for new knowledge must sometimes confound the
old, so that an attribution which seemed perfectly reasonable
when Crowe and Cavalcaselle wrote is rightly subject to
revision as other pictures come to light ; and it is certain,
that human taste being not infrequently only the essence of

generally received opinions, the artistic values set on Old
Masters, especially on minor Old Masters, must be subject to
alteration. A ne\\ edition of the volumes nuist therefore be a
work much larger than the old. much more valuable than the
old, much better illustrated than the old : and the chief
difficulty of the ijublisher must be to find editors sufficiently
catholic to admit the new material, sufficiently eclectic to
prevent a lowering of the standard.

In the fourth of the six volumes in which the work is to be
completed, and which deals with Florentine Masters of the

Fifteenth Century, tliese
requirements are as f.iith-
fully fulfilled inider the
editorship of Mr. Langton
Douglas assisted by Mr. G.
de Nicola, as they were in
the earlier volumes, when
Mr. Douglas had the colla-
boration of Mr. .Arthur
Strong. It is in many ways
the fullest of the volumes
hitherto issued : and the new
notes and references are on
a scale which almost adds
in additional volume to the
• liginal work. The remain-
iiigtwo volumes are promised
during the next year, and the
only satisfactory and com-
plete handbook on the
d e \- e 1 o p m e n t of 1 1 a 1 i a n
painting will be within the
leach of persons of nioder-
.ite means.

i:

S. G

An Ovster Catcher's Nest.
Hab

I'liotograpliy for Bird

Lovers. — B\- Bi:xTLiiV

l; l-HTHAM. F.Z. S. 126

Pages. 18 illustrations.

Si-in.X6-in.

iWitlierby & Co. Price 5 -
net.)

The accompanying illus-
ti ation. which we reproduce
li\- the courtesy of Messrs.
Witherby & Company, shows
how carefully Mr. Bentley
lieetham has studied his
subject, and how nuich he
1^ able to put into his
|iictures, for the photograph
which has been reproduced
lint only shows the nest and
iggs of the Oyster Catcher,
but also indicates in no small
degree the kind of site which
the bird selects. The book
consists chiefly of instruc-
tions telling the would-be
bird-photographer how to proceed. After apparatus has been
dealt with, the photographing of nests and young birds, the use
of stalking and concealment methods, not to mention rope
work on the cliff faces, the taking of birds in flight, in colour,
and by means of the cinematograph are considered. It is truly
surprising how much information and how many beautiful
photographs have been included in this small volume.

PSVCH()I.( )(,V.

Body and Mind : .4 history ,nid a defence of Animism. —

By \\"1L1.1A.M McDcU I, Air . M.B. JS4 pages. 13 illustrations.

9-111. ■ .Tj-iii.

(Methuen & Co. Price 10,6 net.)

This book, as we are informed in its preface, contains " a
critical surve\- of modern opiihnii and discussion upon, the

A suggestion of the Binl'^
itat.

December. 1911.

KNOWLEDGE.

487

psjxho-physical problem, the problem of the relation
between body and mind." Its anthor has clearly done his
utmost to present his material " in a manner not too dry and
technical for the general reader who is prepared to grapple
with a difficult subject." and truly the subject is a difficult one.
Nevertheless, the writer must be warmly congratulated on his
bold attempt to make clear that which is to most so obscure,
for the definite line of argument which pervades the whole
book will make it difficult for any reader who systematically
studies it to miss the author's meaning on any one of its
closely covered pages. The book is a book for students,
amateur and professional, and may be described as a scientific
defence of Animism, the theory of the existence of the soul.
The author clearly shows that there is no alternative between
.Animism and the most absolute Materialism, and boldly stands
for the foi-mer ; indeed the present volume is perhaps the first
really scientific attempt to justify the soul theory. But it is
nuich more than this, for the first half at least is occupied
with a " survey of modern theories of the psycho-physical
relation," and without this the reasoning of the later chapters
is almost impossible to follow.

The book is clear and concise and excellently written, and
though wholly unsuited to the casual reader is most
emphatically to be recommended to anyone of average
intelligence, who has made up his mind to systematically
grapple with this difficult but interesting subject.

PHYSICS.

Trctitise on Practical Light. — By Reginald S. Clay.
519 pages. 408 illustrations. S-in. X 5-' -in.

(Macmillan & Co. Price 10 6 net.)

Dr. Clay's treatise which is an enlargement of his well-
known " Practical Exercises in Light," is a book which will
be welcome to many. There are many books which deal with
optics from a theoretical point of view, from a geometrical
standpoint er as an entertaining subject for the lecturer.
There has long been required a book which collects together
the various methods of optical measurement. Works on
Practical Physics contain sundry optical measurements, but
seldom can one find just that process of measurement that
one requires. Dr. Clay in his introduction says, " There
can be no doubt that it is to the advantage of the
optical industry both that the difficulties manufacturers
find should be known to those whose scientific training may
assist in their solution, and also that the experimental methods
which have been adopted by individual manufacturers should
be known to each other, as well as to those whose interest may
be chiefly theoretical. The chapters on aberration of lenses
and mirrors and on the compound lens illustrate the above
statement, and show that the author has written a book which
comes up to these excellent ideals.

The book commences with a chapter on simple pin experi-
ments— some most useful, such as the determination of the
angle of the surfaces of a piece of nearly parallel glass, and
all very instructive to the beginner. This leads up to a chap-
ter on the position and nature of images formed by mirrors
and lenses, dealt with in a simple manner ; and then more
completely in a chapter on the focal length of lenses and
mirrors which contains many \aluable methods and even
means of obtaining the radius of curvature of very small
lenses as used for microscope objectives. Chapters follow on
optical instruments, deviation and dispersion of light, the
velocity of light, and focal lines. The adjustments of the
spectrometer are well described ; it is such descriptions that
make a practical treatise of good value, and it would have
been pleasing to have found a rather fuller account of the
method of working refractometers, spectrophotometers, and
other refined optical appliances. The author's admirable love
of simplicity causes him to omitfullerdescriptions of instruments
such as the echelon grating spectrometer, and various inter-
ferometers and refractometers, and perhaps this is to be
regretted, since the research chemist has sometimes to use
such instruments and is often rather ignorant of the correct

method of manipulation, and requires some handbook 'to guide
him. However, the chapters on interferometers, diffraction,
colours of thin and thick plates and polarised light will be
most useful to the student of optics, who has hitherto
had to search in man\- different volumes to find the many
different instructive experiments the anthor has collected in
these chapters. The chapters on vision, colour measurement,
resolving power, the compound lens, and the microscope are
thoroughly up to date, and contain a great deal of very useful
information, useful both to the student and to the technician.
It remains to say that the printing, figures and general
arrangement of the book are excellent. A r r F

Principles of Physics. — By William F. Magie. Ph.D.
570 pages. 281 illustrations. 9-in.X 5|l-in.

(G. Bell & Sons. Price 7,6 net.l

The author mentions in the preface that Physics is the one
science of all others in which scientific reasoning is illustrated
by the simplest and most varied examples. The peculiar
advantages of the science as a means of intellectual training
are not given sufficient attention, as physics is now commonly
taught ; and the author has endeavoured to present the
subject in such a way as to direct attention particularly to
the development of its various branches and thus to exemplify
the processes of thought which are employed in the examina-
tion of a .group of physical phenomena and the establish-
ment of a physical law or theory. The book is consequently
constructed upon the historical outline.

The result is an interesting survey of the science of physics,
cramped in certain sections of the book a little too much, e.g.,
electricity, but nevertheless a book useful both to the elemen-
tary student and especially to the man who requires a general
outlook on Natural Philosophy without having to call to his
aid his mathematical facilities, or to bother his memory with
a host of details which must be included in any book on
Physics which includes the numerous practical applications
of the Principles of Physics. The author avoids complication
by rigorously keeping only the main principles of the science,
and b\' excluding many side issues, e.g., dynamo-electric
machinery, steam engines, and so on. \ C C V

An E.yperiinental Course of Physical Chemistry. — Part I.:

Statical Experiments. — By James F. Spencer, D.Sc, Ph.D.

228 pages. 65 illustrations. 7J-in. X4j-in.

(G. Bell & Sons. Price 3/6.)

This work, says the author, has been written to provide the
student of Physical Chemistry with a guide which shall enable
him to carry out for himself the simple physiochemical
operations. Dr. Spencer commences well with a chapter on
errors and interpretation of results, and continues with a valu-
able chapter on the calibration of instruments, weights, measur-
ing vessels, and thermometers, another on constant temperature
baths, and on the manipulation of gases. These chapters are
the most important part of the book, for knowledge of how to
work accurately, and consequently of how to calibrate one's
instruments, is all important to the physical chemist. When
once apparatus is properly set up and its errors determined,
accurate measurements are not difficult. Some account of
the setting up of cathetometers, and reading microscopes and
the calibration of fine capillary tubes might, with advantage,
have been included.

The rest of the book deals with the determinations of
various physical constants, and the descriptions are very clear
and concise. Density, atomicity, molecular weights, solubility,
viscosity, surface tension, polarimetry. spectroscopy, refrac-
tivity. and thermal measurements are dealt with in succession.
-A useful collection of tables is to be found at the end of this
well got up and useful book. The student of physical
chemistry will find most of what he wants in this small book
and can always refer for greater detail to Ostwald and Luther's
'■ Physiko-chemische Messungen " ; the one is a laboratory
working guide, the other a reference book, .\nother volume
of dynamical experiments is to follow this volume shortlv.

.A. C. G. E.

4S8

KNOWLEDGE.

December, 1911.

General Physics for Students. — By
pages. 285 illustrations.

l.Macniillan & Co. Prico 7 6.)

F.invix Hi)Si:r. Cti2
in. \ 4i-iii.

Mr. Edser's physical books, those on light and heat, are
already very well linown and much admired for their clearness
and arrangement. The bool; on the Fundamental Properties
of Matter now under review is part of the same series of
books and is even of higher standard than the other two text
books. It is a new book — that is to say. it contains material
which w-as not to be found in any other book. Mr. P^dser has
collected together a great number of physical facts and prin-
ciples into a small volume of six hundred pages, and arranged
them so adroitly that there is neither cramping nor loss of
clearness. .A good book for the advanced student and research
student on the properties of matter has long been required ;
the former working for examination had no time to consult
the larger treatises, such as Chwolson's Treatise, and it was
often not worth the research student's while to wade through
a large mass of literature after a small matter. Mr. l-^dser's
excellent book supplies the need. The chapters on the spin-
ning top. on gravitation, on surface tension, and on the
molecular structure of gases will be of great interest to all
students of physics.

" The student who possesses a sound knowledge of the
elements of algebra, geometry, and trigonometry will find his
acquirements are sufficient to enable him to read the book
without referring to mathematical treatises " : this sentence is
taken from the preface, and the author has been led thereby
to work all proofs from first principles and to avoid the calculus
as far as possible ; this is a pity, perhaps, because the calculus
simplifies many arguments, and most students of physics have
at some time or other to get famili.ir with it : and it is somewhat
irksome for the more advanced student to work through a
proof from first principles each time. To some it is more
pleasant to be led up to a subject from the mathematical
standpoint and then to compare the experimental with the
inductive results ; others care to do the experiment, form a
mechanical picture of what is happening and then to apply

mathematics to get that picture into a more exact representa-
tion of what is occurring. Mr. Edser seems to prefer along
with many other physicists, the former plan ; the latter would
appear the more natural to the elementary student. Only in a
few places in this book does this tendency become apparent,
and on the whole it is exceedingly clearly written and
arranged.

The printing and diagrams are very good : there are very
few misprints (on page 14 "melting" occurs instead of
resulting).

The book is bound to please everyone in whose hands it
finds itself, and is a valuable asset and help to those studying
natural phenomena. i f~ r F

lUnniuiation : Its Distrihiitlnn and Mcasitreinent. — By

.'\lexander P. Trotter. 292 pages. 209 illustrations.

0-in. X S'l-in.

(Macniillan & Co. Price <S d.)

This book does not deal with the many illamiuants of the
present day, but rather with the methods by which they may
be used to the best advantage, an equally important study.
In order to be able to determine quantitatively the effect of an
illnminant at any particular position it is necessary to be able
to measure the intensity of the light at that place. Mr.
Trotter has himself devised many useful forms of apparatus
to attain this end and describes in addition all the other forms
of apparatus in use. The book is a mine of information for
the user of the Photometer. The author has worked up the
history of this most important class of instrument and has
presented a very complete account of its various forms. The
three chapters on the distribution of illumination contain a
great deal of useful original work which will be of great value
to the engineer engaged in the proper lighting of buildings and
streets.

The book is spli inlidl\- i^ll-^tr.lted and is printed in very
clear t\pc ; while it contains a valuable bibliography at the
end. It will be indispensable to the user of photometers and
to the iUiiniinating engineer. A C C F

NOTICES.

CHRISTMAS GIFTS.— In view of the approach of the
■^'ule-tide gift season we would direct the attention of our
readers to the fact that most scientific and optical instruments,
including cameras, lend themselves admirably to the material
expression of goodwill among relatives and friends, and that
such, chosen with regard to the particular interests of the
recipients, would be sure to find a warm welcome with them.

PHYSICAL TR.AINING .AT BIRMINGH.-\M.— We
recently had the pleasure of seeing the work which is carried on
at the .Anstey Phvsical Training College, near Birmingham, and
we hope soon to public an article dealing with the scientific
side of Swedish Physical F^xercises, by Miss .'\nstey, the
Principal and F'onnder of the College. There is no quicker
way to Birmingham than by the two-hour expresses of the
London and North-Western Railway. No less than forty trains
run daily between Euston and Broad Street and New Street —
a most frequent service.

WELLCOME TROPICAL RESEARCH LABOR-
.\T( )RIF;S. — Messrs. Bailliere.Tindall and Cox, the well-known
medical publishers, announce that they have been authorised
by the Department of Education of Sudan (jovernment, to
publish immediately the F'ourth Report of the Wellcome
Tropical Research Laboratories, Khartoum. The Third Report
was issued in 1908, since when a great amount of important
research work has been accomplished, and the announcement
that a further instalment is to be expected should arouse the
keenest interest among students of Tropical Medicine.

The thorough examination of the conditions of tropical life,
as they present themselves in men, animals, and plants,
is the task to which this great institution is devoted, and the

Fourth Report, which is in three volumes, contains facts,
observations, and discoveries recently brought to light. It is
the actual record, at first hand, of new contributions to the
solution of problems of deep and world-wide importance.

The edition is, howe\er, limited, and in order to ensure
delivery of copies immediately upon publication, it is essential
that orders should without delay be ft)rwarded to the publishers.

TREASURE TROVE.— The Committee of the South
Eastern Union of Scientific Societies on Means of the
Preservation of Treasure Trove and other Relics, has issued
a second edition of its pamphlet upon the law of Treasure
Trove together with a sheet of illustrations showing in an
attractive manner the sort of articles which may be found
and ought to be preserved. Mr. H. Norman Gray, the
honorary secretary, is sending copies to various county
museums and other institutions for exhibition and reference,
and although the Committee is inclined to the opinion that
public nmseums should be the homes of all finds of interest, it is
only concerned with the preservation of the finds, and there-
fore private collectors need have no fear from any action
from this Committee. The printing and circulating of the
literature entails a considerable amount of expense and the
Committee invite contributions to aid it in its useful work.

SCIENTIFIC BOOKS.— We have received from Messrs.
W. & G. Foyle their catalogue of technical and scientific
books. The great feature of it is the way in which the various
items are carefully listed under alphabetical headings. The
index contains over two hundred difi'erent subjects, so that it is
easy to find any one recjnired without the trouble that usually
has to be expended in looking through catalogues of books.

I'rim«l for ill-; l'n.piiet.ir> ( Kllnwiedue I'ul.lishin;.; Company, Limile.l), l.y |nn\ Kl>jr„ 1 ;iliiit; ;iik1 Uvliriilsf-

INDEX.

ACIDITV OF BOGS, 547.
Attinosphactiufu euhornii^ S<jme notes on,

298.
Adlam, Thos. R., 182.

'* Adria " The Austrian research vessel, 210,
African glacier, A Central, 70.
Air, Investigation of the upper, lOg, 443.

results. Upper, 151.

, The Meteorology of the upper. 373.

.Albatross, The flight o'f the. 471.
Alcyonarians, Copepods an<-i, 1 16.
Alga from the Seychelles Islands, 11 1.
Algol, The system oL 147.
Alkaloids as plant food, JI4.

on plants, .\ction of poisonous, 25.

AUotropy, 358.

.Alloys, .Magnetic, 410.

.-Altitudes on the eats. The effect of great, 1S2.

.Aluminium nitride and its uses, 442.

-Alundum, Properties of, 31S.

.\mpall. The, 409.

Aniphidmuim operculaUim Clap and Lach.4Sl.

Anabcuna ciicinalis, 354.

Analogy, A quaint structural. 78.

Angles, A method of dividing, 435.

-Aniline stained microscopic preparations, The

prevention of fading of, 192.
.Animalcule, found in a ditch near Norwich,

466.
.Annison, .A. L., 213.
.Announcements, 93.
.Answers, (Queries and, 39, 49, 103, 135, 181,

225, 412.
Antarctic birds, 283.
.Anti-cyclone. 182, 225.
.Ant Society, .A primitive. 4S4.
Ants, Larviil mantids mimicking, 115.
.Apes at Gibraltar, Barbary, 452.
Aquatic animals. Food supply of, 410.
.Arctic north west, .A Scandinavian tribe in

the, 464.
.Argon, A new method of preparing, 70.
.Aristotle's Lantern as an organ of locomotion,

410.
.Arsenic in sea weeds, 279.
.Arthropods, .Mounting minute, 2S5.
Associations. 451.

Astronomer Koyal for Scotland, 23.
.Astronomical appointments, 46.

Queries, 311, 411, 427.

Society of Barcelona, The, 67.

.Astronomy, 22J.

, A bird's eye view of the history of, 204.

and geography, 39.

as a peace promoter, The political import-
ance of, 254.

, Bible, 330. 339.

, Chronometrical ciiart of the develop-
ment of, (facing page 204.)

, Meteoric. 126.

notes, 23, 67, 105, 147, 185, 229. 276,

313, 347.401, 436, 478.

sectiim at the Coronation Exhiljilicm.

The. 371.

; The application of photography to tund-

amental, 185.

Astronomy, Tiie new, 362, 379, 413. 426, 453,

472. '
.Atmosphere in winter. Constitution of the,

103.

, .Measurement of pollution of the, 27S.

, Mineral constituents of a dusty, 351.

.Auk, .An egg of the Great, 1 12.

Aurora borealis, Recent investigations on.

127.
.Australia, The flowing wells of Central, 404.
.Automobile Club's suggested laborator)*. The

Royal, 156.

B.ACTEKIA AXD CROP PRODUCTION.
S(_)IL, 123.

, Cytology of the, 280.

, Iron, 105.

, Luminous, 190.

Barcelona, The Astronomical Socieiv of, 67.

Barclay, H. D., 48.

Barnard, J. Edwin, 192.

Barttum, C. O., 311, 427.

Bartrum's third query. Air. 436, 472.

Bean industiy. The Soya, 70.

Beaumont, Comyns, 464.

Bee disease, 450.

Bees, Colour sense of. Hive-, 34.

Beet, root, .A new fungus in the, 230.

, Distribution of sugar in the, 404.

Beetles in nests, 4S5.

Bellamy, F. .A., 23, 67, 94, 1 1 8, 131, 370.

Benham, Charles E., 117, 471.

Bible astronoiny, 330, 339.

Bickerton, Professor .A. \V. ,362. 379. 413,

453. 472.
Bickerton s theory, Fresh support for, 324,
Bingley, C. S., 435.
Biological Horoscope, The, 157.

the

Ljreater

Biology, Magnalia naturae ;
problems of, 410.

notes. Economic, 26.

of a hay infusion, 2S5.

Bird, .A new British, 76, 237.

life on the Caernarvon coast, 92.

marking. 398.

of Paradise singing, 446.

Sanctuary, The Brent v.alley, 361.

The .Alpine Ring Ouzel, .A new British.

355-
. The Sleniler- Billed Curlew, .Another new

British, 446.
Birds and migration. .Marking. 98, 355.

, Antarctic, 2S3.

are there. How many kinds of British.

"3-

attached to wires, Rotatiim of stufted,

181.
breeding in the London Zoological

Gardens, 323.

. Flightless. 325.

from New Guinea, 193.

in the eleventh edition of the

"Encyclopaedia Britannica," 191 1, 323.

Birds. Irish, 112.

learn to sing, How young, 86.

new to Scotland, in 1910, 406.

of Paradise, Collecting and Protecting,

237-

• St. Albans, The, 2S2.

■ on migration. Speed of Hight of, 112.

, The encouragement of insect eating, 99.

, flight of, 174.

, Tweed, 446.

Bison and domesticated cattle. Fertile hybrids,

between, 115.
Bittern nesting in England, 40S.
Black game vermin ? .Are. 323.
BHnd, Sense of direction in the, 451.
Block. The Process, 460.
Blood stains, Estimation of the age of, 479.
Blow-fly larvae respond to gravity, Do, 78.

, The flying apparatus of the. 324.

Bogs, -Acidity of, 347.
Bologna luminous stones, 441.
Borielly's Periodic Comet, 47.S.
Botany at the British .Association, 403.

in California, 25.

the Encyclopaedia Britannica, 477.

- — - notes, 25, 69, 105, 147, 186, 229. 276,

313. 347, 403. 478.
Bo/iydinm graiuiliitiim, (L.), 322.
Boulger, G. S., 4.

Boyd Alexander Collections, The, 76, 2S2.
Bradshaw, Walter, 412.
Brent A'alley Bird Sanctuary, The, 361.
Britain, Pre-glacial flora ol, 347.
British -Association, The, 93, 359.
, Botany at the, 403.

Museum (Natural History), The, 288.

, The spirit buildings at the, 324.

Brook, .Arthur, 97.

Brooks' Comet, 347, 478.
Brown, Myles, 472.
Bryce, David, 235.
Bullbrook, J.A., 175.
Bulman, G. VV., 86.
Burton, J., 444, 481.

Bustard in Norfolk in 1900. The Great,
446.

C.ACT.ACEAE, AFFINITIES OK, 69.

Caernarvon Coast. Bird life on the, 92.

t:affyn, C. H., 31. 75-

Calculator, Plaskitt's simple\, 146.

California, Botany in, 2^

Caiman, W. T., 227.

Cambrian ^ea-cucumbers, 359.

Carbon and lime, Action of steam upon, 232.

in gold ore, 232.

Cartilage, .A tell-tale, 45 1.

Caterpillar, Svmhiotic micro-organisms in a,

2S5.
Caterpillars, Procession, 78.
Cattle, The ancestry of domestic, 104.
Cavendish Laboratory, The, H-

111.

ixiM-:x.

Cavers, Professor F. , 25, 6q,

147, 1S6,

229, 2-6, 313, 347, 403,^478
Cellose and Cellase, 315.
Cellium, A new elenieiii. 149.
t'elaceans a iwofold origin ? Had. 79.
('haniuers G. F., 16.
Chandler, K. H., 302.
Chandra. R. G , 243.
Chcmislry at llie Brilish Association, 44I.

notes, 25. 70. 107. 149. 1S7, 2I0. 231.

27S, 317, 350,404. 479.
Chirocephaiits .iiuphann^, 466.
Chloroplasts in seedhiigs. Origin of, 313.
Chroniium conipotinds on plants, Influence cif.

iSS.
Chronometrical chart of the development of

astronomy, facing p.ige 204.
Ciliary and muscular movement-, 157.
Cinematographic hand -camera, A, 203.
Clare Island survey. 445.
Clark. J. Edmund. 373.
Clalkrina coriiu'sa. The division of the cullar

cells in, 7;.
Clayden, A. \V., 15S.
Climate and physical conditions in I're-Cam-

brian times. iSS.
Clusters and nebulae, 342, 4I2. 471.
Coal, Algal, 314.

resources of the United Kingdom, The,

472.

. Spontaneous combustion of. 187.

. ignition of, 149.

Titmouse (Pants /ti'iennois). The Irish.

355-
Cocaine, The detection of, 231.
Coles, Alfred C, 193.
Collar cells in Claiithrina Coiiaidi, The

division of the. 75.
Collinge. Walter E , 26.

Colour filters upon the definition of a lens.
The eflfects of, 155.

in deep water, 34.

Condjs, \'ariatioris in fowls*. 359.
Comet, Borrelly's periodic, 478.

, Brooks', 347, 47S.

, D'Arrest's, 105.

. Encke's. 229, 347, 401.

, Faye's. 23.

. Halley's, 23, 105, 1 35, 225. 229. 243.

Notes, 436.

Comets, 313, 401.

, 1911, a. and C, 411.

, Naked eye, 427.

Conifers. The ecology of, 25, 313.
Copepods and .-\lcyonarians. j 16.
Corals in the North Sea, .-^re there black, 34.

Islands. The origin of, 27.

Corn-crake, More about the, 409.

or landrail (Crex Joalensis), Decrease in

the, 237.
Corf)nation Exhibition, Science at the, 212
Correspondence, 13, 46, 10 1, 141, 243. 270,

311, 335' 411. 471-
(correspondents. Notes for. 113.
Cosmic changes, 243.

Cosmos. The Galaxy and an immortal. 453.
Crab and Ilyilroid, Association of, 4S3.
Crexpralemis, Decrease in the corn-crake or

landrail, 237.
Crick, Henry, F., 412.
Crounnclin, A. C. 1)., 105, 147, i8v 220. 276,

jl-'. 339. 347, 401, 436, 47-'- 478. '
Crossbills in the British Isles, 154, 194.
Cn)w. The Carrion, 225.
Cruciferac, Structure of flciwer in, 478.
Crystals, The pass.age of light through, 189,
Curlew. Another new British bird. The Slender

Billed, 446,
Curtis, John A., 28, 72, loS, 151, 1S9, 233,

280, 319, 352, 405, 443, 4S0.
Cuttlefish, Large, 483.
Cycad root-tubercles. to6.
Cyclas embrvos, Inci
Cyclone, .Anti-, 225.
Cysiopiis caiididui Pers. (white rust) on
Capsella bursa Pasloris^ (Shepherd's
Purse), 407.

Cytology and Embryology in
"Encyclopaedia Britannica," 367.
Cytology of the bacteria, 2S0.

the

nf Myutar

DARLING, CHARLKS k,, i.

D'.Vrrest's Comet. 105.

Davidson. The Rev. M,, 46. 226, 411.

Davison, Charles. 51. 107,

Deeley, G. Plant, 354, 333.

Dennett. Frank C 6. 5c, 102. 130, 142, 170,

243, 245- 273 312." 346. 395-' 4'';4
Denning, 47, 116. 126, 244 256, 335, 399,

46S.
De Roy. Felix, 25, 69.
Developers. The fogging powers of, 283.
Diaphrag.n. The tlieory of the Iiis. 114
Diatom valve. The true structure of the. 289.

welding. \ case of, 444,

Dimension. "The fourth, 270, 311, 411.

Dimensions generally, and the effect of tlie
fourth -dimension in particular. Concern-
ing, 213.

Disease l>y house flies, Dissemin.ation of. 283.

means of books. Transmission of.

Diseases, The spread of infective, 26.

Ditcham. George, 48.

Doberck. W. , 173.

Dieams, 39. 50, 135,

Drops of liquid. A sini[>le experiment on the

formation of, i.
Dukes, T. -Arch, 471.

EARTH, THE LINING, 450.
Earthquakes, British. 51.
Eclipses, 40,

, Total, 315.

Ecology, Papers on, 43S.

Egerton, A. C. G., 114, 155, 196, 238, 2S3,

357. 409. 448, 4S3-
Egg, A black, 193.
Eggar, W. D., 7, 33, 77.
Electrica. Ophthalmia, 44S.
Electricity, Rays of positive, 196.
Electrographs, i ;S.
Element, Celtium. A new, 149.
Elliott, J, John, 243, 270.
Ellipses, On drawing, 264.
Embryology in the "Encyclopaedia Biit-

annica." Cytology and, 367.
Enamel, Grecian black, 317.
Encke's Comet, 229, 347, 401.
"Encyclopaedia Britannica" (1911). 323, 367.

Botany in the, 477.

Flight aud flying in the, 435.

Fourier's series in the, 418.

Microscopy in the, 40S.

Engineering, Science and, 34.

Enock, Fred, 271. 297, 40c.

Enlamocba coii, 354.

I'.ocene floras, 69.

Equatorial by means of ciicumpolars. On

adjusting an, 423.
Ergot, Flies and. 240.
ICrrata, 437.
I'.ruption, of Taal volcano in the Piiilippine

islands, The recent, 197.

, The great New- Zealand. 108.

Eternal return. The, 48, 102, 144. 243.

Euglena Ehr., 48 1.

Euphorbia peplus. Radiations from Latex, 447.

Eutectics, 167.

Evolution, Momenuim in, 410.

Exoasiiis deformans. Berk (Peach Curl), 407.

Experimental tank. Work at the National

Physical Laboratory, The National, 169.
I\ves, The inclined position of the apparent

vertical meridians of the, 47.

Encyclopaedia
On the occur-

410.

green plants.

Encyclopaedia

FAIRV FL^-, A new, 2SS.

, The discovery of the femal

regalis. The new, 297.
Fat bv protozoa, the non-digestibility of.

laulds, Henr)', 130.
F.aye's Comet, 23.
Fermentation, Citric, 14S.
Fern I'^mbryos, Suspensor in. 25.
I''ilaments for electric lamps, 107.
Finger print method, (Jrigin of the, 141.

piints. A chapter in the history of their

uses for personal identification. 136.

Firel>all of November l6th, 1910, The Leonid.

1 16
Fire-flies. Luminescence of. 285.
Firefly, The luminosity of the, 410.
Fishes. Muddy taste in freshwater, 77.

, ^'aw^ing in, 78.

Flagellates in freshwater fishes. Transmission

'of, 151.
F'lannelette, "Non-inflammable." 404.
Fleas and plague, 240.
Fleming, Dr. J. .A., 266.
Flies and disease, House, 26.

Ergot, 240.

in winter, 26.

Flight and flying in the

Britannica," 433.
Flints in Paleolithic gravels

rence ot some small finely woiked, 14
Floiaof Britain, Pre-glacial, 347.
Flour, The digestibility of bleached, 26.
Flower, The evolution of the, 231. 277.
Food in bordered pits. Reserve, 314,

supply of aquatic animals

Formaldehyde as food for

239.
Fothcringham, W,, 41.
Fourier's Series in the

Britannica," 41S.
howls' combs, \'ariations in, 339,
Fry, .-\gnes, 102.

Fulmar's breeding range, The, 446.
Fungi, .\mbrosia, 315.

and bacteria. Papers on. 440.

. Recent work on the lower, 106.

Fungus in Liverworts, 231.
hurze thorns, 231.

(iALAXV AND AX LMMORTAL

COS.MUb, THE, 453.
Galton, Sir Francis, 45.
Gas in (ialicia, Natuial, 441.
Gases. The viscosity of, 155.

without flame. Combustion, of 149.

Gemstone, A gigantic, 279.
Genius ami isolation, 412.
Geography, .\sl ronomy and, 39.
Geological survey of Scotland The, 149
, New Memoirs

318- ...
Geologists Association, The 188.
Geology notes, 27, 70, 107, 149, 188,

279, 3 > 8, 351, 404- 479-

of South Dorset, 412, 472.

Geophysical Jotirual, 4S0.
CJeotectonic symmetry, loS.
Cieotropisni, Some recent work on, 147.
" Germanol,'' 25.
Gibb.s, G. U., 412.

, W. B.. 264.

Gilinan, Fred, 102.
Gilpin-Brown, L (i., 423, 433.
Glasgow memoir, The new, 479.
Glazing of ancient Greek vases, The, 23.

on Grecian pottery. The black, 1S8.

Gneissose banding. Original, 150.

Gnetales, Recent work on the, 14S.

Gold ore, Carbon in, 232.

Goldschmidt Redaction, The, 249.

Gongy/ia viridis, A. L. Sm., in Surrey and

Essex, A New Lichen, 1S4.

INDEX.

Gradenwitz, Dr. Alfred, 210, 2i;7.
Gravity, 330, 339, 412.

• , Loading Ijricks by, 451.

on Eii^lfiia Tiiiiiis, The etlect of, 32.

Grecian lilack enamel. 317.
Grew, K. .S., 10, 169.
(">rouse .and disease, 355, 409

, Coccidiosis in, 2S1.

on the Continent, The Red, 257.

Gulf Stream, The, 39. 49.

( iunnery, H.. 40S.

Gwinnell, Russell !•'., 27, 70, 107, 14U, 18S,

232, 279.
Gyro-compass, The, 1S5.

HABIT, A CURIOUS. 240.

Habrolhioeha hidiiis (Gosse), On the identity

of, 234.
Hairs, I'lant, 163, 247, 428,467.
Halley's Comet, 23, 105 135. 225, 229, 243.
Handedness, Right and left, 115.
Uandwritin;;, Family, 302.
llardcastle, J. A., 50, 327
Hardness of minerals, The, 150.
Harman, \V., 103.
Harris, David Fraser, 21, 60.
Harrison, B. G., 160,471.
Hastings, Sonierville 3S9.
Hawkins, H. Periani. 141.
Hearing, Which is the fastest, sight or, 104.
Heat and a \acuum, 285, 412, 433.
Heath, C. E., 73, 235.
Hebrides, A new industry in the, iSS.
Hedgehog, The awakening, 359.
Heliotropism, 106.

Heliozoi'm, An inteiesting marine, 2S5.
Helium in the air of \^esuvius, 149.

, Liquid, 358.

Heloderma, Bite of, 450.
Henkel, F. W.. 342, 471.
Hermit Cral), Hydractinia and, 240.
Heron, .\ proposed census of the common,
76. ,
lerrings" eggs, slowing deNelopment i.>f, 450.
erschel, W. J., 141.

— , His telescopes and work, William, 244.
.gh water. The lime of, 327.
Hill, J. Arthur, 225, 419.

, Matthew Davenport, 325

loney, Bacteriological study of, 278.
lony, G. B., 296, 335.
.lornbilFs stomach, 359.

' lorsehair. The zoological side of commerce,
3S4.

vood, A. R., 92.

e-flies. Dissemination of disease by, 285.
on, R. ,\., 87.
Edmund John, 29S.
ninson, H. B., 123.
The Rev. H. N.. 89, 128.
E. Adnin, 423.
nd Chimaeras, Graft, 1S6.
/etween Bison and domesticated
Je, Fertile, 113.
.tachiia s;eo,s;raf'hiiti Mull, Note on, 75.
dracarina of Clare Island, 320.
.._,draclinia and Hermit Crab, 240.
llydrocjuinone. Development with. 77.
Hydrostatic apparatus illustrating the law of

development, A, 195.
Hydrui us foclidiis \'ill. 320. 354.

IDENTIFIC.VTION' BY FINGER I'RINT.S,

■ 36.
Igneous complex and its origin. An, 232.

rock composition, 70.

rtjcks. The great provinces or branches

of, 279.

Ignition of coal, Spontaneous, 149.

Illumination, 246.

and ultra-microscopic \ision, Daik

ground, 425.
Image, An "explosion" theory of the Latent,

33'

Images and the size of the particles which
cimipose them, The relation between the
colour of silver, 154.

Inaudible sounds, 409.

Incubation of Cyclas embryos, 2S3.

Infusion, Biology of a hay, 2S5.

Inks, Tri-colour printing, 323.

Ions from hot substances. Positive, 483.

Insects, \'easts of, 451.

Institution. The Royal, 85.

Irish biids, 1 12.

Iron bacteria, I05.

Isulaiion, Genius and, 412.

JEFFFRV, W. S., 1S2.

Johannesburg, Snow in, 29.

Joseph. T. K . 182.

lupiler. The eighth satellite of, 147, 313.

KEEGAN, P. Q., 15.
Kites in the upper air, 4S0.

LABRADOR A LAND OF PROMISE, 232.

Lambert, The Rev. F. C. , 340, 448.

Lamps, Filaments for electric, 107.

Latex, The functions of, 347.

Leaves fall? How and why do, 4.

Leitz, Dr. Ernest, 73, 426.

(London) and R. Winkel (Gottingen) E.,

III.
Lens, The effect of colour filters upon the

definition of a, 155.
Leonard, Frederick C, 312, 41 1.
Leonid hreball of November l6th, 1910, The,

116.
I.epidoptera, Innervation of wings in, 4S4

, The scales of, 235.

Leptomonad in Euphoyhta^ 157.

Le Verrier, The centenary of Urbain Jean

Joseph, uS.
Lewis, I\. T,, 236.
Lichen, Gongylia viriJis, A. L. Sm., in

Surrey and Es.sex, A new, 184.
Lichens, The biology of, 376.
Light sources, Standard, 113.

. The velocity of, 412, 471.

through crystals, The passage of, 189.

Lighting, Globe, 286.

LutinochiOay Notes on the African freshwater

niedusoid, 359.
Limiiui, The genus, 135.
Lishman, W. E. , 144.
Liverworts. Fungus in, 231.
Lowerison. Bellerljy, 39.
Luminous stones, Bologna, 441.
Luminescence of liiellies, 285.
Lunar eclipse, 49.

MACIWSPOKIUM FRIES, 406.

Maggois, Blood sucking, 484.

Magnalia naturae, or the greater problems of

biology, 410,
Magnetic alh^ys. 410

.Maidenhair tree (OV«/'tf /^/ij/'d). The, 316.
.Mapp, Charles R.. 217.
iMaize sugar, 230.

.-?■-•

Notes on the .African
32, 76, 113. 154, 194,

The, 7<>.
112, 152,

193.

Makower, Walter, 262.
Mantids mimicking ants. Larval, 115.
.Maori customs and beliefs. Some, 63.
Marine Ilelizoon, An interesting, 285.
.Mars, 185, 402, 47S

, Observation of Uranus and,

, The spectrum of, 105.

Martianum, Lumen, 182.

McCarthy, J., 426,

.McHarg.'john, 19S, 306.

Mechanics, l-.xperimental, 7.

Mediterranean. Notes of a naturalist in the, 2g6

.Medusoid Liiiiuoihhla^

l-'reshwater, 359.
Mees, ('. E. Kenneth,

237, 283, 323, 356.
Meker burner. The, 26.
Mercer, A., 3y
Mesolhorium, 156.
Meteor, A., 141.
Meteoric Astronomy, 126.

phenomena of September 2nd, 1911, 399.

shower of September 30th, 468.

Meteorological photographs, 378.
Meteorologv notes, 28, 72, 108, 151, 189,

233, 280, 319, 352 40;, 443, 479.

of the upper air. The, 373.

Meteors, 181.

Mice carry their yi.iung. How long do white,

450.'
Micro-cinematography, 288.
fauna of a sewage filter bed, 353.

-fungus from the Japan British Exhibi-
tion, 235.

-object from a singular source. An inter-
esting, 153.

Microlo^st, The, 74, 193, 320.

Micronucleus in regeneration. The infusorian,
4S0.

Microscope lamp, A new 73.

Microscopic study of dry plates

Microscopical Clui.i, (^Hiekett,
236, 281, 321, 482-

.Science, Quarterly journal of, 408.

Society, The Royal, 31. 73, III, 152,

192, 236, 282, 321, 4S2.

Microscopv, A new table for practical, 340.
, in the new " Encylopaedia Britannica,''

408.
Microscopy notes, 29, 73, 109, 151, 190, 234

2S0, 320, 353, 406, 4S0.
Migration, 76.

" rush,' A, 194.

Marking birds on, 112.

Minchin, George M., 270.

Mineral constituents of a dusty atiinjsphere,

3 si-
Minerals, The hardness of, 150.
Mitchell, C. Ainsworth, 25, 70, 107, 149,

1S7, 219, 231, 27S, 317, 350, 404, 479.
Mitosis, Micro-slides illustrating, no.
Momentum in evolution, 410.
Monchiquites in Britain. Porphyritic, 405.
Monckton, O. Paul, 305.
.Moon and the weather. The, 47, 142.

, (Colours on the eclipsed, lOI.

, The new French tables of the, 436.

, map of the, 141.

Moon's distance. New determination of the,

276.
Morphology, Recent work on experimental,

349-
Morton, Reginald, 81.
Mosquito, sucked by midge, 359.
Mosquitoes, Spiders and, 240.
Motor car. Unique American steam, 253.
Mountain building and ore deposition, 336.
Mounting minute arthropods, 285.

, On lluid, 235.

Mourning for a dog, A native in, 88.

MuUins, Alfred J. ,411.

Murray, James, no.

Mussels, Rings on Freshwater, 240.

Mutton bird oil, 231.

Myiita>\ A notable record. Capture of a new

species of. 271.

lega/is, The new Fairy fly, 297.

INDEX.

NATIONAL COLLECTION AT SOUTH

KENSINGTON, THE. 482.
Natural History Olijects, Apparatus fur

Photographing, 41.
NaturaMst in the .Mediterranean, Notes of a,

296, 372.
Nebulae, Clusters and, 342, 412.

, Star Clusters and, 413.

Nebula in Orion, The Great, 2.

Negatives, The development of quantities of,

Nerves and Nervousness. 21, 60.

Nesting sites for birds, 98.

Niiiiiiama tiiangularu I'iersig, Note on a

VV'ater mite new to Britain, 234.
New Guinea, Birds from. 193.
. The British Ornithological Union

Expediti(m to Central, 154.
, Ornithological Expedition, The

Central, 112.
Newton, The late Professor Alfred, 154.
New Zealand eruption, The great, loS.
Nightingale. First occurrence in Scotland of

the. 322.

, The distribution of tlie, 2S2. 335.

Nitrogen, Active, 197.

, Chemically active, 351.

Nitrogenous salts in sea water, I06.

Norwich, Animalcule found in a ditch near,

466.
Notes, 23, 67, 105. 147. 1S5, 229. 276, 313,

347, 401-
Notices, 36, 3S. So. 122, 144, 146. 203, 222,

228, 246, 2SS, 330, 372, 412, 477.
Nova lacerlae. 105.

. (Kspin), Variable or, 68.

Persei. The story of, 362.

Nuclei in flowering plants, Male, 107.
Nucleoproteins, The, 230.

OIL, MUTTON BIRD, 231,

Optical propeities of vapl)ur^, 23S.

Ore deposition, Mountain building and,

336-
Ornithological Expedition, The Central New

Guinea, 112, 154, 237.
Ornithology notes, 22,76, 112, 154, 193, 236,

282, 322, 355, 408. 445, 482.
Oviparous and vivipar<.His. 115.
Oviposition of Tachinidae, 425.
Oysters, Washing, 34.

PAINTS. K I K K PROOF AND

SUB.MARINE. 149.
Palaeo-botany. Papeis on, 439.
Paleolithic gravels. On tiie occurrence ol

worked flints in, 14.
Pallas and d. Acjuarii, 103.
Papers, Miscellaneous, 441.
Paradise birds, Acclimatiang, 356.
Parallaxes, Stellar, 401.
Parkinson, \Vm., 425.
Parr, \V. Alfred, ;6, 204, 427.
Parthenogenesis, Artificial, 240.
Partis hiheriiiciis. The Irish Coal-titmouse,

355-
J'aulson, Robert, 184.
Perkins, Frank, C, 253, 451.
Petrograpliical provinces, 442.
Phonograjjh, A New, 222.
Photographic Society, The P^xhiliition of the

Royal, 1 14. 237.
Photographing Natural History objects.

Apparatus for, 41.
Photographs, Infra-red, 32.
Photography, for Bird lovers. 154,
notes, 32, 76, 113, 154, 194, 237, 2S3,

323. 356, 4S2.

Photography. Latitude of exposure in Land-
scape, 356.

, Some notes on plant, 389.

to fundamental astronomy, The applica-
tion of, 185.

upon paper, Colour, 4S3.

Photometer. A new^ type of, 122.
Photomicrography for naturalists. Low power,

446.
Pliysical Laboratory, The National, 156.

experimental tank. Work at the

National, 169.

Physical Society, The annual General Meeting
of the, 115.

of London, 93.

Physics notes. H, TJ, 114. 155. 196. 23S, 283,

324> 357. 409, 4^3-
Physiology, Papers on, 440.
Pigeons. Terrestrial magnetism and carrier.

446.
Pigments. Tiie mystery of the Floral, 15.
Pipes. Use of copper for water. 317.
Plague. Carriers of, lo.

, Fleas and, 240.

Planets, Minor, 49-
I'lankton, The Dwarf, 321.
Plant hairs, 163. 247, 42S, 467.

photography, .Some notes on, 3S9.

Plants, Influence of chromium compounds on,

ISS.

, Male nuclei in flowering, 107.

Plaskitt, F, J. W.. 49, 335.

Plates, The microscopic study of dry, 76.

Platinot\'pe printing. 357.

Plover. Maritime habits of the Lapwing re-
sembling those of the Kinged. 92.

Podura scales, 13, 48, 143.

Poison, Tetrodon, I07.

Polar phenomena, 46, 339.

Pollution of the atmosphere. Measurement of,
27S.

Poly/reiiia (Foraminifeia), The genus. 281.

Poole, H. H., 384.

Porphyritic monchiquities in Britain, 405.

Porthouse, William, 67.

Postal reform, 226.

Potterv, The black glazing on Grecian.
188.

Poultry, Sparrows and, 157.

Pritchard. L. N , 225.

Process block, The, 460.

Protozoa, Non-digestibility of fat by, 77.

of the soil, 2S1.

Psychical research, 419.

Purkinje phenomenon. The, 426.

Pyramid, Orientation of the Great, 135.

(QUARTZ VEINS, 442.

(Juekett Microscopical Club, 30, 112, 152, 193,

236, 2S1. 321, 482.
Queries, 285, 330.
and Answers, 39, 49. 103, 135, iSi 225,

339,412,472-

, Solutions to Mr. Bartrum's 347.

Query, Mr. Bartrum's third, 436.

RADI.VTIONS, 449.

from Latex of Euphorbia peplus,

449-
R.adio-activity, 339, 433
active recoil. 262.

fialancc. The. 77.

Radium, 39. 49, 104.

Biological action of, 350.

emanation. The density of, 156.

— ■ — in Uranium ores, 351.

preparation. A new, 279.

The transformation of, 318.

Raft'ely, Charles W.. 49, 412, 433.
Rain, Artificial, 412.

Rainfall of 1910, The, 72.

, The S. E. Trades and, 29.

Raingauges, Ancient, 151.
Ram. Francis, 174, iSi. 225.
Rays ol positive electricity, 196,
, Sterilisation of water by means of ultra-
violet, 70.

, The ultra-violet, 114,

, Waves versus, 77.

Rea. 11. E., 460.

Kedgrove, II. Stanley, 249, 312, 329. 369.

Red-snow, lOy.

. Some wiirks referring to, 1 52.

Redstart reported nesting in England. Black,

482.
Reid. R. W., 63.
Reissner's filire. 96.
Reptillian aimalure. Evolution of, 78.
Research vessel "Adria," The .-\Ublrian, 210.
Reviews, 34, 79 119, i^T. 162. 200, 241, 286,
328, 36S, 39S.

.Aeronautics, 79, 200.

.Archaeology, 119, 328

.Astronomy, 34, 119. 201, 241.

] bacteriology, 32S.

Biology, 12b, 137, 328.

Botany, 35, 120, 157, 201. 2S6, 32S, 36S.

Chemistrv, 79. 157, 203, 24:, 286, 328, 368,
_ 39S.

Entomology, 2S6.

Geography, 398.

Geology, 35, 80, 120, 286, 369, 398.

.Mathematics, 242, 287. 328.

Medicine, 121.

.Meteorology, 121, 329.

Micrology, 329.

Microscopy, 287.

Nature Study, 329, 368.

Ornithology, 203.

Philosophy, 369.

Photography, 80.

Physico-chemistry, 162.

Physics, 36, 162, 202.

Physiological Chemistry, 121.

Physiology, 36, 122.

Psychology, 329.

Technology, 242.

Tides, 287.

Topography. 287, 330.

Zoiilogy, 36.
Rhizocephalon, A freshwater. 3^9
Rhodes, I. E. W., 167, 336.
Ridpath.'C. 11. E., 225.
Ring Ouzel. A new British bird, The .\lpine,

355-
Rock composition, Igneous, 70

grinding machine for amateurs, .A, 30.

section, Tlie preparation of a, 74.

Rocks, The great provinces or branches of

Igneous 279.
Rodrigues, Canyos, 425.
Rook, Accounting for the, 282.

. Judgments on the, 236.

Root-tubercles, Cycad, 106.

Rotation of stuffed birds attached to wires, 181

Rourke, Edmund, 103.

Rowlands, S. P., 39.

Royal Institution, 470.

Rust on Cap-iella bursa Pastoris (Shepherd's

Purse) Cystopus candiilus Pers. White,

407.

SANDPIPER ( rOTANUS HYPO-
LEUCVS), THE COMMON. 301.

Sandeman, John Glas, 103.

Salt Lake, The water of Great, 70.

Scales of Lepidoptera, The, 235.

Scandinavian tribe in the Arctic North West,
464.

Science and engineering, 34,

at the Coron.ation Exlnbiiion, 212

in every-d<ay life, 89, 12S,

Masters, The Association of Public

School, 66.

INDEX.

Sciencf, The South African [oitrtial of, 22S.

Scientific Notes, 243.

Scotland, First occurrence of the Nightingale

in, 322.
, New memoirs of the geological survey of,

318.

, The geological survey of, 149

Scottish Highlands, The problem of the, 31S.

Scourfield, D.J., 321.

Scutigera. Habits of, 450.

Sea, The origin and peopling of the deep, 107.

cucumbers, Cambrian, 359.

'i\eeds. Arsenic in, 279.

Sediment, An inexpensive apparatus for the

systematic separation of. by means of

heavy solutions, 217.
Seismography at a London exliibition, .A, 324.
Seismology, 197^ 324.
Stlagint-lla, Spore dispersal in, 550
Selenium 448.

photometer, The, 270.

Sense org.an. A new kind of, 78.
Seychelles Islands, Alga from the. ill.
Sh'ackleton.W., 37, 65. ico, 14;, 180, 223, 274,

294, 360, 396, 469.
Sheppard, A. W., 29, 73, 10c, 151, 190, 234,

280, 320, 353, +06, 480.
Shrimp, The Brine, 227.

, The Fairy, 240.

Sight or hearing, Which is the fastest, 104.
Silver-fish, Brain of a 115.
Simulacra vitae^ 116.

Skeletons of vertebrates, Hints on the pre-
paration of, 175.
Sky, The Face of the. 37, 65. 100, 145, 180,

223. 274. 294, 300, 396, 469 473.
Smith, F. P , 30

-, T. F., 13, 144, 289, 331, 335.

Snail, The hibernating, 450.

Snails ( /V(?»[>;'/^.'^ ("(Vn^'wi). Waler. 472.

Snow in Johannesburg. 29.

Soar, Charles D., 73, 320.

Soil Bacteria, Crop production, 123.

. Protozoa of the. 28 1.

"Soil wax" and soil fertility, 186.
Solar Disturbances. 6, 50, 102, 130,

273, 312, 346- 395. 4^4-

179.
;o6.

projection. Discs for, 198, 206.

spectrum, 472.

.Sounds, Inaudible, 409.

Space infinite, Is. 141, 243.

Sparke, Lieut. -Colonel. J. G. , 3y.

Sparrow Hawk, The. 97.

Sparrows and poultry, 157.

Specificity. 240.

Spectrograph, .^ new spectroscope and. S7,

Spectroscope and spectrograph, .A new, 87.

Spectroscopic double stars, 47.

Spectrum, Colours of the. 2S5, 433.

Spermaceti organ, 34.

" Spheroidal state," 357.

Spider, A .Myrmecophilous. 29.

Spiders and mosquitoes, 240.

Sponge, A remarkaljle, 359.

Spore dispersal in Selagiiiella, 350.

Slalagmitic growth in sea water, .\., 479,

Star Clusters and Nebulae, 413.

work. The present state of variable, 23,

68.
St.arch in a leaf, Demonstration of the presence

of, 59.
Starling as a mimic. The, 482.
Stars by amateur observers. On the study of

double, 16.

, Diameters of, 147.

, Double and wonder, 379.

, Notes upon the fundamental system of,

94. Iji- 370-

. On the proper motions of the fixed, 173.

, Practical hints on observing double, 16.

-, Preliminary general catalogue of 6188,

67.

, Spectroscopic double, 47.

, Spring and Summer shooting. 256.

, Strange. 412.

, Variable, 403.

Ste.im upon carbon and lime. Action of, 232.

Stellar motion and spectral type 478.
Stereoscope, .-V scientific use for the, 205.
Sterilisation of water by means of ultra-violet

rays, 70.
Stigni.as, Sensitive. 34S.
Stonyhurst College Observatory, 222.
Stopford.'F. G., 471.
Stork breeding in the " Zoo." White, 237.
Structure of flower in Cruciferae, 478.
Stuart, .■\. H., 205.
Styan, K. E., 163. 247, 42S. 467.
Sugar in the beet root. Distribution of, 404.
Summer of 191 1, The, 443.
Sun, Figure of the, 436

spot groups of 1906. The, 43.

the Distance of the, 49.

Sundial. .\ unique, 30;, 372.

, .\ simple method of constructing :i

horizontal, 117.
Sun's distance detei mined from Eros. Tlie,

276

Revolution, The, 141.

Suns, .Artificial mock, 102.

Surface brightness. The Measurement of

Survey, Clare Island, 44;.

" Sweepings." 400.

Swift (Cypscliis a/iis). Abundance of

Common, 323.

104-

the

TAAL VOLCANO IN THE PHILLIPINE
ISLANDS, THE RECENT ERUP-
TION OF, 197.

Talianidae. 444.

Tachinidae, Oviposition of. 425,

Tail, H. Sinclair, 339.

Taylor. E. W.. 301.

, Fred B., 426.

Telegraphy, Wireless, 225.

and the weather. Wireless, 103.

for time signals. Wireless, 478.

Telephone cables, On lo.ided, 266.

Telescopes and work, William Herschel, 244.

Termites, Rhythuis of activity among 2S3.

Tetraspora (Link), 444

Tetrodon poison, 107.

Thomson, F. Ross, 49.

, Professor J. Arthur, 34, 77, 115, 157,

198, 240, 285, 359, 410, 450, 483,

Thunderstorm in Garessio, 424.

Tides, 39, 104.

Time at night. The finding of the, 39, 103,
104.

by day. Finding the, 1S2.

the heavenly bodies. Finding the.

103, 135
in France, Adoption of Western

European (Greenwich), 147.
Portuguese Territories, Standard.

425.

, To find approximate sidereal, 426.

Titanium, Properties of metallic, 3;t.

Titmouse. Coal, 355.

Train, The effect of rigid rails on the speed

of a, 225.
Trees, Wounds in, 140.
Tribe in the arctic North West, Scandinavian,

464,
Turbellarian, A new Commensal, 78.
Turner, Henry, 43.
Tutt, .lames William, 43.
Tweed birds, 446.
Tyrrell, G. W., 318, 351. 404, 479-

ULTR.A-MICROSCOPIC VISION. DARK
GROUND ILLU.MINATION AND,

425.
Underwood, JLieut.-Col., 14.
United Kingdom. The coal resources of the,

472.

Uranium, 358.

ores. Radium in, 351.

Uranus and .Mars, Observation of, 313
— Vesta, Observation of, 33;,

VACUU.M, HEAT AND A. 2S5, 412, 433.

tubes, .Afteiglow in, itj.

Vapours, Optical properties of, 238,

Vases, The glazing of ancient Greek, 25.

Vatican Observatory of to-day. The, 56.

Venus antl the inference to be drawn from the
probable atmospheric condition of ihe
planet. The problem of the rotation of, 1(10.

, Rotation of, 471.

Vertebrates, Hints on the preparation of
skeletons of, 17 5.

Vesta, Observation of Uranus and, 335.

N'esuvius. Helium in the air of, 149

Vinegar Industry, The. 219.

\'iviparous. Oviparous and. 115-

Vulcanism, New theories of, 351.

254.

236. 2S2,

280,

WARNER, Irene E. Ttiye

Wasps. A book on, 39.

Water and its own level, 39, 49, 103, 1S2.

finding, 182, 225.

fowl in the Zoiilogical Gardens, London

mite new to Britain, [Neumania hiangit

laris Piersig) Note on a, 234.

The cooling of hot, 330

, Wind and, 27.

Watt. Hugh Boyd, 76, 112, 154, 193

332, 355, 408, 445. 4S2.
Waves versus rays, 77-
Weather, The, 28, 72, loS, 151, 1S9. 233,

319, 352, 405, 443, 480.
, Wireless Telegraphy and the. 103.

Insurance, 190.

, The Moon and the, 47, 142.

Webb, Geoff'rey Ker, 225.

, Wilfred Mark. 240. 3S4.

White, The home of Gilbert, 330

Wilson, Humphrey. 339.

Wind and \^'ater, 27.

Winkel (Gottingen). E. Leilz (London)

1 1 1.
Wire, Movement of a taut, 181.
Wombat, Habilsof the, 34.
Woodpecker. New names for the Green, 445
Woodpigeon. .A novel bait for, 193.

pest. The, 154.

Wounds in trees. 140.

X-R.\VS. 81.

. Nature of the. 114.

and

V.\WNING IN FISHES, 78.
Veasts of Insects. 451.
Verward-James, W. E.. 103.

ZANARDINIA. LIFE HISTORV OF, 230,
Zoological Gaiden, An antediluvian, 257.
Gardens, Birds breeding in the London,

323.

, Waterfowl in the, 154.

side of commerce. Horsehair, The, 3S4.

Zoology notes, 34, 77, 115, 157, 198, 240,

2S5, 324, 359, 410, 4S0i 483-

Q
1

,ovle<3ge

phyycal &
Applied Sci.
Serials

CARDS OR SUPS^^O^ATH^S

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