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t5.Zic.64-.

THE

POPULAR SCIENCE

REVIEW.

A QUARTERLY MISCELLANY OF
ENTERTAINING AND INSTRUCTIVE ARTICLES ON
SCIENTIFIC SUBJECTS.

EDITED BY HENRY LAWSON, M.D.

VOLUME VI.

L 0 N D 0 N :

KOBERT HARDWICKE, 192 PICCADILLY;

AND ALL BOOKSELLERS.

1867.

LONDON

PRINTED BT SPOTTISWOODE AND CO.
NEW-STREET SQUARE

CONTENTS OF YOL. YI

PAGE

Ox the Mode oe Growth of some of the Alg^. Illustrated by
a few of the Common Kinds. By J. Braxton Hicks, M.D., F.R.S.,

F.L.S., &c. Illustrated ... ... ... ... 1

The Geology of Sinai. By the Rev. E. W. Holland, M.A. ... 10

The Planet Mars in January, 1867. By Richard A. Proctor,

B.A., F.R.A.S. Illustrated 22

On Water Filters. By Edward Divers, M.D., F.C.S. Illustrated 33
Our Fresh-water Entomostraca, Shell-Insects, or Water-

Fleas. By W. Baird, M.D., F.L.S. Illustrated... 42

How to Photograph Microscopic Objects. By Edward T. Wilson,

M.B. Oxon. Illustrated ... ... 54

Recent Discoveries in Insect Embryogeny. By Henry Fripp,

M.D. Illustrated ... ... ... ... ... 110

On the Struggle for Existence amongst Plants. By J. D.

Hooker, M.D., F.R.S 131

How to Study Meteorology. By G. F. Chambers, F.R.A.S.

Illustrated ... ... ... ... 140

On Sensitive Flames. By W. F. Barrett. Illustrated 154

Paraffin Lamps and their Dangers. By John Attfield, Ph.D.,

F.C.S 167

An Attempt to Approximate the Date of the Flint Flakes

of Devon and Cornwall. By Spence Bate, F.R.S. Illustrated 169
Venus’s Flower-basket (Euplectella). By Dr. J. E. Gray, F.R.S.

F.L.S. Illustrated 239

Jupiter without his Satellites. By Richard A. Proctor, B.A.,

F.R.A.S. Illustrated 248

Fitz-Roy Weather Forecasts. By G. F. Chambers, F.R.A.S.,

Illustrated ... ... ... ... 258

On Life Insurance and Vital Statistics. By W. Hardwicke, M.D. 271
New Electro-Magnetic Machines. By. S. J. Mackie. Illustrated 281
The Botany of a Coal Mine. By William Carruthers, F.L.S.

Illustrated ... ... 289

The Microscope in Geology. By David Forbes, F.R.S. Illustrated 355-
Why the Leaves Fall. By Maxwell T. Masters, M.D., F.L.S. ... 369
‘A Message from the Stars.’ By Robert Hunt, F.R.S 378

IV

CONTENTS.

On the Planarih: of our Ponds and Streams.

PAGE

By E. Ray

Lankester. Illustrated

...

388

Ventilation and Ventilators. By the Editor. Illustrated ... 401

Physics of the Brain. By B. W. Bichardson

, M.A.,

M.D., F.R.S. 415

Reviews of Books

...

66, 185, 299, 428

Scientific Summary — Agriculture

...

79

Astronomy

...

80, 196, 309, 441

Botany

...

87, 199, 313, 448

Chemistry

...

90, 202, 317, 453

Geology and Palaeontology

...

95, 207, 322, 459

Mechanical Science

...

98, 212, 327, 464

Medicine

...

100, 218, 330, 466

Metallurgy, Mineralogy, and Mining ...

...

104, 215, 335, 471

Microscopy ...

...

105, 223, 338, 477

Photography ... ... ... ...

...

106, 227, 339, 479

Physics

...

110, 230, 344, 483

Zoology and Comparative Anatomy ...

...

114, 234, 349, 487

T.Wejst sc.

WNhst re

POPULAR SCIENCE REVIEW.

ON THE

MODE OF GROWTH OF SOME OF THE ALGAE.

ILLUSTRATED BY A FEW OF THE COMMON KINDS.

BY J. BRAXTON HICKS, M.D., F.R.S., F.L.S., &c.

TT\ HE botanist who confines his attention to the study of the
JL flov^ering (or, as they are called, phanerogamous) plants
has a task relatively easier than he who devotes his attention to
the so-called simpler forms of vegetable life. For, even if we
exclude the fact that the principal portion of the phenomena of
the former is visible to the naked eye, the changes which they
undergo are considerably less and more regular than those of
the lower order, and by far more easily observed. The term
“ simple ” can only apply to the more simple composition of
their component parts, while the number of changes which their
forms undergo more than counterbalance this point in the time
and trouble required for observation. Besides this, the tedium
of watching the changes they pass through, and the difficulty of
preserving them in their natural condition in order to secure
the same changes, make their study one of much more arduous-
ness than is to be found in observing the higher classes. Take,
for instance, the growth from the seed : how easy it is to
observe its construction and its germination, the formation of
the various parts, the radicles, the ascending stem, the leaves
with their various appendages, the flower and its parts, lastly,
to the ovule. There is one rather difficult subject, however,
which is not to be seen without care — namely, the fertilisation
of the ovula, or young seed. Yret the difficulties attending the
study of the lower (flowerless, or cryptogamia) forms are of a
different class. Here the study requires protracted watching ;

VOL. vi. — NO. XXII. B

2

rOPULAR SCIENCE REVIEW.

and as most of them are of aquatic habits, exceedingly suscep-
tible of any change, whether in the amount of light or in the
quality of the water, the trouble of keeping them under con-
stant observation has done much to retard our knowledge of
them, and to render the number of our observers small. Add
to this that their outward forms change considerably, if not in
some instances completely, and that the changes once induced
may continue as long as the same external conditions which
produced the changes remain.

To this point I have already called attention in a former
paper, and its importance in this study is of great moment.
Formerly the old observers were content to consider each form
as the permanent condition ; and in works of not many years
since it may be read how this species of Protococcus or that
of Oscillatoria, &c. were sent dried by post. This was un-
avoidable in the infancy of the study, but now it is indefensible ;
and nothing must be considered but as provisionally placed
whose whole mode of growth has not been well observed.

After these remarks, let us now pass on to the consideration
of those phenomena which attend the propagation of the fresh-
water algse, or, as they are also called, “confervoid algse.” And
in examining these, we shall meet with some very interesting
changes. But first of all it may be as well, for the benefit of
those who have not as yet made themselves acquainted with the
plants in question, to give an outline description of the forms
in question.

They may be formed of one or of many cells, but in the latter
case there is generally very little difference between each. Some-
times, indeed very commonly, the cells are joined end to end;
each cell, like other vegetable cells, is composed of a cell- wall, or
transparent external firm coat (fig. 1, a ), and of the cell-contents ,
or soft-coloured matter, generally of a green colour, and hence
called u chlorophyl ” (fig. 1, b). Now the cell-wall has no active
vitality, this is possessed by the cell-contents ; but as these in
general would be injured readily, the cell-wall is for their pro-
tection, and to increase their solidity. The green cell-contents
are disposed in different manners in different plants, and in
different times in the same plant. Very commonly there is a
colourless transparent body near the centre of the green mass*
and this is called the nucleus (fig. 1, c; fig. 9, a; fig. 12, a).
This was supposed to be the most active vital part of the cell,
and as it is frequently the first to be divided in the process of
cell-division, it was considered of essential importance. How-
ever, inasmuch as in some cells it is not found at all, and as in
them cell-division goes on all the same, some doubt must be
entertained in regarding it the essential part of the cell.

Although the arrangement of the cell-contents is variable.

ON TIIE MODE OF GROWTH OF SOME OF TIIE ALGyE.

3

both in the same genera and species, and at different phases in
the same species, still in some the form it assumes is very con-
stant for the same phase of its life, particularly in some species.
Thus, in Spirogyra (fig. 8), it enables us to distinguish the
plant at once, because it assumes the form of a spiral band
attached to the inner surface of the cell-wall, giving it an
exceedingly beautiful appearance. In some confervoids, it is
more or less stellate. In the mature cells of the larger Drapar-
naldise (fig. 2; a green branching seaweed-like plant, adhering
to stones in running streams), it is disposed in a band round
the equator of each cell. In many the contents are granular,
in some homogeneous, or of uniform consistence. The number
of cells in a single plant varies from one up to many hundreds ;
indeed, as they are all derived from one by its division con-
stantly, there is really no limit, except such as imposed by the
time required for it, and by the change of external circum-
stances, such as the seasons bring, which check the progress of
that particular phase.

The most remarkable phenomena of the freshwater algae are
those which are concerned with the multiplication and the
reproduction of the species. Broadly, it may be said that every
cell of an alga is capable of living, growing, and multiplying, if
separated from its neighbours. Still, nature has so arranged
that there are cells frequently more especially devoted to this
end ; and there are times in its life when the process more dis-
tinctly goes on. In order to understand these processes, let us
for a moment notice the mode in which this process takes place
in the true algae, or seaweeds. In these is to be found the
representative of that mode of fertilisation adopted in the higher
orders by means of pollen. Now it will be remembered that
when the pollen-grain (fig. 3, a) falls upon the moist end of
the style, namely, the stigma, it produces from certain parts
small delicate tubes. These tubes (fig. 3, b, b) penetrate the
substance of the style, passing between their cells (fig. 3, c, c )
to ultimately reach the ovule, or future seed. Acted upon
by it in some unknown way, the latter becomes fertilised, and
ultimately ripens into the matured seed.

Now, in the true algae, the representatives of the pollen are
called “ antherozoids.” Each consists of a very minute cell,
having one or two fine hairs, or cilia, spring from one end, or
one from each end (fig. 4). These cilia have the power of moving
in a screw-like manner, whereby the cell is propelled. In the
common bladderwrack of our coasts, the process may be readily
observed on the bulbous ends of the fronds. If a thin section is
made, cavities opening on the exterior will be seen to have been
divided. Placed under the microscope in water, branches (fig.
5, a) may be seen springing from the wall of the cavities, the

VOL. vi. — NO. XXII. c

4

POPULAR SCIENCE REVIEW.

end cell, or antheridia (fig. 5, b), of which contains these anthe-
rozoids, each of which has a yellow spot in the centre. When
the cell-wall breaks up, the latter bodies become free (fig. 5, c),
and come in contact with the spore, or ovule (fig. 5, a). These
are also found in the same cavity, among the roots of the
branching antheridia. These spores thus become fertilised, and
thus the mode resembles very much the enclosed flowers of the
common fig.

Let us see how this is carried out in the freshwater algae.
We will take a very common instance, Vaucheria. It is com-
posed of green filaments ; growing in ponds, on damp earth,
in ditches — it does not particularly dislike, as most of the algae
do, those which are fragrant, but flourishes freely, becoming a
tangled mass of very tough fibres on the surface of the water.
Although it slightly branches yet it is not jointed, and by this
it may be known from almost every form with which it grows.
It is indeed only one cell, sometimes attaining many inches in
length. The chlorophyl, which is of a deep-green colour, is
generally applied to the inner surface of the cell-wall ; at one
end is found a sort of root of colourless branches, whereby it
attaches itself to any objects. The other end of the branches is
rather club-shaped, of much darker green, and more dense.
Now to those who rise very early in the morning in summer, the
following facts may be revealed by nature. A short distance
from the club-shaped end (fig. 6, a), a line of separation may be
observed ; after a time, the end of the tube bursts, and the con-
tents now escape (fig. 6, 6), and assume an oval form, covered
with minute vibrating hairs, or cilia, which propel the mass in a
rotatory manner in the water (fig. 6, c). This may be called a
zoospore ; perhaps, as it has a number of cilia all over its sur-
face, it may be considered rather as an aggregation of ordinary
zoospores."* After a few hours, this zoospore falls to the bottom
of the vessel, loses its cilia, its walls become thicker, and soon
after, a process arises from it, which is the beginning of another
tube. This is a good example of one, perhaps the most common,
plan by which these common forms are multiplied. This pro-
cess is repeated rapidly, and thus this species increases fast.

But this is not the mode which is analogous to that of the
seaweed. This is accomplished by the following arrange-
ment : —

* At certain parts of the tube, the observer may find elevations
springing from it in pairs (fig. 7), one of which is in the form of
a hook, or crosier (fig. 7, a), the other oval, with or without a
stem (fig. 7, b). Sometimes on the same stem there are more than
one oval process. Now it is in the hook-like process that the

* See paper on lC Volvox ” in this Review, vol. v.

ON THE MODE OF GROWTH OF SOME OF THE ALG.E.

5

antherozoids are formed, itself is the antheridium (like those
before described in the seaweeds), from which they escape in due
time. In the other process is matured an oval body (fig. 7, 6),
which represents the ovule, or future seed of the higher orders..
An opening in the apex of the process leads down to it, and
through this the antherozoids pass to fertilise it. After a time*
this ovule escapes by the solution of the wall of the process, and
acquires a firm external cell-wall. But unlike the other spore
above described, it has no power of motion ; though ultimately
it grows out, as the other spore, into an elongated tube like its
parent.

This plant can be observed in the early spring in a state of
fructification, as soon as the frosts have abated ; the earlier the
better. They can be preserved for observation on the surface of
a pot filled with ordinary garden mould, or sand, kept well
moistened. If placed in the sun, it will be best to invert a glass
over it. It may be found fructifying very well on the shady
sides of the furrows in fields.

Thus, then, in this plant we have two forms by which multi-
plication of the species takes place, one by throwing off a
“zoospore,” the other by the fertilisation of a cell, which may
be called the ovule, or 66 oospore,” or egg-spore.

We will now direct our attention to a third form to be ob-
served in a considerable section of the confervoids ; and in
doing so, it will be well to watch the whole life-history of one of
the plants in wThich it occurs, as far as at present known. Let
us take the common Spirogyra, of the family Zygnemacese.

From early spring to late autumn may be found in ponds
and pools, the sweeter and clearer the better, a number of fila-
ments of light-green colour, of an inch or two in length. Place
these under the microscope, and you will at once recognise the
plant by the beautiful green spiral band above-mentioned, to
which the plant owes its colour.

There are many species, but they all are very similar in pro-
ducing the phenomena to be immediately mentioned.

It will next be noticed that it is divided into a number of
compartments or cells, joined end to end linearly (fig. 8). In
some species there are more than one green band, two or three,,
like a many-threaded screw. In a few there are two spiral
bands, which run in opposite directions.

In the active growth of the plant, it may be observed that the
component cells divide into two by sending a process across, or,
as some believe, it is effected by a separation of the contents
into two equal halves, and then each half throwing a cell-wall
around itself. However this may be, the one cell becomes nowr
two. If this continues with rapidity, each cell is much shorter,
but after a time the growth of each part goes on, and thus the-

6

POPULAR SCIENCE REVIEW.

filament becomes much longer. This is the ordinary mode by
which the growth of filaments in the confervoids is effected.
There is one more point of interest in the cell of this plant. In
the centre (fig. 9) you may perceive, by a little trouble in
44 focusing,” a transparent colourless body, giving off arms to
all parts of the cell, so that it is suspended in the centre. This
is the nucleus, and allusion has been made to this body above.
Through the centre of this nucleus passes the line of division
above described.

But the phenomenon which has attracted so much attention
from observers is that which has been called 44 conjugation,”
and thence the class of plants in which this takes place (for
there are many) have been called the Conjugated. As the term
implies, the process is a joining together of two cells. Ordi-
narily, it takes place between two cells of two neighbouring
filaments ; a projection is sent out by each, which meet and
unite. During this time, the green spiral band of each cell losing
its character, the coils melt together, and then those of one
side pass over through the tube of junction into the other cell,
mingling with the other green mass ; and they then are intimately
blended into one large oval green mass, the spore (fig. 10, a, 6).
Soon after this the spore becomes hardened on the exterior, a
cell-wall is formed round it, and it is subsequently liberated
upon the dissolution of the parent cell ; in the course of the next
spring it elongates, the contents assume the form of the spiral
band, and a cell is thus formed like those of last year ; in due
time, it divides as before mentioned, and thus a filament of
Spirogyra is reproduced. In some of the species of this genus,
if there is no filament near enough with which to conjugate, the
adjoining cells of the same filament conjugate, for a process is
throughout from each cell round the joint, and then their con-
tents fuse as above described.

Now what is the exact meaning of this curious occurrence ?
Opinions vary somewhat. Some see in it the analogue of the
fertilisation affected by means of the pollen, and, as above
shown, in the Vaucheria, only not carried to so complete an
extent. Others look upon it as a mere vegetative action, because
the contents of the cells involved have no visible difference
before nor during conjugation, and that it is rather to sustain
the vigour of growth in the plant, which it may lose by repeated
division. However this may be, it is at present our safer plan
to continue to watch the process, and also to observe whether,
in the same plant, any real antherozoids can be found at any
time of its life. A careful observation of this plant would be
highly interesting to the observer, and doubtless add valuable
facts to set at rest this question.

Other changes have been observed in this plant. For instance,

ON THE MODE OF GROWTH OF SOME OF THE ALGJ2.

7

the spiral contents coalesce so as to form a number of globular
portions, each leaving tivo cilia at one end, possessing power of
movement in the parent cell. When this latter breaks up, these
bodies move about freely, and appear like the zoospores of
other algge (fig. 11). Again, instead of the contents resolving
themselves into the above form, they become converted into a
star-like form, with firm cell-walls. These again, according to
Pringsheim, bcome converted into active moving bodies, whose
history has yet to be followed.

Some plants conjugate which only consist of one cell (fig. 12, a).
The contents of one cell wholly pass over into the other, or re-
main in the tube of junction, distending it by its growth (fig.
12, 6). A good example is seen in Cylindrocystis Brebissonii
(fig. 12).

Now let us watch another of these lower forms which present,
as far as at present investigated, a simpler, but more rapid,
form than the above in its mode of increase. You may find,
in autumn and early spring, at the foot of trees, walls, and
palings, green wavy filaments, which readily mat together when
taken up (figs. 13-17).

This plant has been called Prasiola. Its early condition as a
single filament was called Lyngbya (fig. 13), and the next
stage Schizogonium (fig. 14), till the writer pointed out the
unity of all these in the Microscopical Journal of 1861.

The first stage consists of a green filament divided into many
cells, the walls of which are rather thick. The green contents
are sometimes uniform, sometimes granular (fig. 13). By con-
stant division of these cells across the filaments, the length of
the filament increases. But after a time another form of divi-
sion arises, each cell dividing at right angles to the former line,
so as to become quartered, and to make four new cells (fig. 14),
and thus the fibre becomes by the growth of each wider, with
the appearance of a colourless line down its centre (fig. 14).
After a time, each of these divisions divides again in the qua-
ternary fashion, and a broad strap is produced, which was called
Schizogonium. By the still further extension of this process,
large flat wavy bands are produced, generally wider at one end,
retaining, however, in the arrangement of the green cell con-
tents, evidence of its mode of origin. This latter form has
been called Prasiola. But after a time this strap-shaped frond
reverts to the filamentous forms (fig. 15), by the converse of
the plan above named. The quaternary division ceases, the
simple filamentous is substituted, and these separate from one
another, ultimately becoming free; and thus the number of
the species is increased. But this is also accomplished upon
another plan. One of the cells of the filament sometimes grows
three times its original size, and then, separating from the rest

8

POPULAR SCIENCE REVIEW.

(13, a')9 it appears like a green ball, becoming what has been
called a gonidium, or spore. If this be kept on a slide in
damp air, it will be found after a time to divide in various
ways (see fig. 17). Some of these divisions become very small
(fig. 17); all, however, after a time revert to the linear or
filamentous form.* No zoospores have as yet been found in
this alga, although they have been observed in a very closely
allied form — namely, the Ulva, a saltwater alga.

These confervoid algse of which we have been speaking
exemplify the mode of growth and multiplication in these
lower forms of vegetation. All of them, from their simple
arrangement, can be readily observed ; but in order to observe
them continuously, they should be placed in as natural a state
as is possible, and that for a considerable period. When
brought within doors, they ought, unless living in water, to be
placed in a damp situation, covered over by a glass, with as
much light as can be obtained ; because the reduction of light
under cover and in a room is very great. A saucer with damp
(not wet) sand, or a piece of sandstone will do well, covered
over by a glass ; on the sand you can place the specimen, or,
if under particular microscopical observation, on a glass slide,
ready for instant use.

But it is very important in the aquatic specimens to secure
some water from the identical ponds from which they were
taken. They are very sensitive to these apparently minute
points, and the vessel in which they are kept should not be too
deep. To have them ready for instant observation, the speci-
men should be placed in a live-box made on purpose, having
an apearture to admit air ; this can be obtained of most opti-
cians. In this manner the conjugation of Spirogyra can be
observed. Vaucheria and Prasiola can be kept best on damp
sand. It may be mentioned that, of the plants above men-
tioned, none require an object-glass above J-inch focus ; gene-
rally, i-inch object-glass will suffice.

Before closing, it may be well to call the attention of the
reader to the circulation to be observed in the cells of
Spirogyra ; it is best noticed near the ends of each cell, and
near the cell-wall. Delicate streams are constantly flowing in
varying lines, such as may be observed in the hairs of the
Nettle, Achimenes, &c. and which has been called 66 cylosis.”

To see this well, a high power should be used, either a J-inch
object-glass, or, even better, a J-inch.

* The same mode is seen in the "broad bands as shown at fig. 16.

ON THE MODE OF GROWTH OF SOME OF THE ALG/E.

9

Fig. 1.
o

3.

4.

5.

6.

)>

7.

V
»
} j

a

9.

10.

11.

12.

yy .

13.

T)

14.

)>

yy

ij

15.

16.
17.

DESCRIPTION OF PLATE.

Simple cell — a, cell-wall ; b, green contents ; <?, nucleus.

One of the cells of the froud of Drapamaldia cruciata — showing
hand of chlorophyl at equator.

Pollen on stigma — a, pollen-grain ; b, b, tubes extruded from it ;
c, cells of the stigma. One of the tubes can he seen entering
between.

Antherozoids.

a , antheridia of bladderwrack ; b, cells in which the antherozoids
are produced j c, free antherozoids ; d, one of the spores.

End of tube of Vancheria Ungeri — a, first stage of spore-forma-
tion j b, escape of spore 5 c, matured spore covered with cilia.

Impregnation of spore of Yaucheria — a , antherozoids escaping
from the antheridial process ; b , spore enclosed in the other pro-
cess; which is open to admit the antherozoids.

Spirogyra quinina.

One cell of same; showing the stellate nucleus.

Same plants — a, conjugation of two filaments \ b, free spore.

Zoospore — formation in same.

Cylindrocystis JBrebmonii — a shows nucleus of simple cell ; b} two
cells, having conjugated, have formed a spore.

Lyngbya — a, gonidium.

Same, growing.

Same, recurring to filamentous form.

Same, throwing off cells which are dividing.

Divisions of the gonidium at 14, a.

10

THE GEOLOGY OF SINAI.

By the KEY. E. W. HOLLAND, M.A.

FROM our very childhood we have been taught to regard the
Peninsula of Sinai as a hallowed land, yielding the palm of
sanctity to Palestine alone. As the scene of the giving of the
Law ; as the natural cradle selected by God for the development
and growth of His Chosen People into an independent nation ; as
the region to which the Prophet Elijah directed his steps in his
memorable flight from the cruel Jezebel ; as the probable abode
of the Apostle St. Paul, when he withdrew to Arabia after his
miraculous conversion, it is indeed a land full of sacred asso-
ciations. But, apart from its great Biblical interest, it is in many
other respects one of the most remarkable districts on the face of
the earth.

Its geographical position has rendered it the connecting link
between Asia and Africa. In the rocks which compose its
mountains; in the shells which strew its northern and southern
shores ; in its scanty fauna and flora, we may trace that bond
of union which connects the physical characteristics of the great
African and Asiatic continents. Bounded also as it is on the
north by the land of Palestine and the Mediterranean Sea ; sepa-
rated from Egypt on the west by the narrow strip of desert
which forms the Isthmus of Suez, and from the once powerful
kingdom of Arabia on the east by the depression of the Wady el-
Arabah ; encircled on the south by the two arms of the Red
Sea, now known by the names of the Gulf of Akaba and the
Gulf of Suez, each of which has at different periods formed
a highway for commerce between the Indian Ocean and the
Northern world, the Peninsula of Sinai has long maintained a
degree of contact with civilisation which the barren character of
its dreary wilderness would otherwise have denied it, and it has
played its part in the rise and fall of some of the greatest nations
of. the East.

The peculiar physical features of the peninsula, no less than
its geographical position, have marked it out as a country of
note. To them it has owed a large extent of the influence
which it has exerted at different periods over mankind ; and it
cannot but prove a subject of deep interest to trace out their
leading characteristics and origin.

THE GEOLOGY OF SINAI.

11

It is a country in the history of which geology occupies a
more than usually prominent position. Being essentially a
desert region, yet at the same time almost entirely destitute of
that mantle of sand which has enveloped and concealed the
natural features of so large a portion of the African deserts, it
owes its grandeur, no less than its barrenness, to the nature of
the rocks of which it is composed. It is difficult for those who
live in such a land as ours, which owes its charms to its
luxuriant vegetation, to conceive how a country which is described
as beiug almost entirely devoid of vegetation, can have any pre-
tensions to beauty. Yet, apart from all its sacred associations,
I know of no country which impresses itself more vividly upon
the senses than the southern portion of the Peninsula of Sinai.
“ It combines the three grand features of earthly scenery — the
sea, the desert, and the mountains.*’ The lack of vegetation is
compensated for by the bright colours of its rocks, which, when
lighted up by the rising or setting sun, produce an effect the
beauty of which it is impossible to describe ; the want of rivers
and lakes is supplied by the frequent views of the deep-blue sea,
which present themselves from almost every point in the Sinaitic
range ; and the wild grandeur of the mountains, ever varying in
form and structure, dispels the monotony which the absence of
trees would otherwise beget.

The northern portion of the peninsula, which is generally
known by the name of the Desert of et-Tih, or u the Wander-
ings,” is very different in its character from the southern. Here
the granitic and sandstone rocks give way to limestones ; and
the mountains lose their bright colouring and fantastic forms,
and assume, a tabular outline and glaring whiteness, of which
the eyes of the traveller soon weary.

The hydrography no less than the geology of these two
portions of the peninsula, naturally leads us to separate the
one from the other, and describe them as independent districts.
This course I shall now follow. But in order to render my
description of the county intelligible, I must first explain the
meaning of the Arab word 6t Wady,” which I shall be compelled
frequently to use, since there is no English word which exactly
corresponds to the idea expressed by it. The word “ valley,”
perhaps, most nearly expresses it ; yet even that word, compre-
hensive as it is, does not include the full meaning of the
Arab “ wady,” which is applied equally to describe the broad
valley of several miles in width ; or the narrow course of
the mountain torrent with its rugged bed, and overhanging
cliffs, which scarce permit the loaded camel to force its way be-
tween them ; or again the slight depression in a plain, the depth
of which may barely suffice to afford a channel for its drainage.
The northern desert of the Till is still but little known ; in

12

POPULAR SCIENCE REVIEW.

fact, a large portion of it yet remains entirely unexplored. A
few travellers have crossed it from different points, and have
published rough sketches of the routes they have taken ; but we
have not sufficient data for any accurate description of it. I
shall therefore confine myself to a few general remarks upon
its character, grounded chiefly upon observations of my own
during two hurried journeys across it — the first undertaken in
1861, when I rode from the southern pass of Bakineh in the
Jebel et-Tih, by the castle of Nukhl, and Beersheba, to
Hebron ; the second in 1865, when I traversed the desert on
foot from Akaba to Suez, following the course of the Hadj
route, or road taken by the pilgrims from Egypt to Mecca.

This desert may be briefly described as consisting of an ex-
tensive plateau of limestone rock, supported and enclosed on the
south by a long range of mountains, which, commencing on the
west, runs for a distance of nearly sixty miles almost parallel to
the Gulf of Suez, under the name of Jebel er-Bahah ; and then
changing its name to that of Jebel et-Tih, and circling round
towards the east, shapes its course in the form of a festoon,
suspended from the heads of the two gulfs of Suez and Akaba.
Throughout its whole course, this range presents a singularly
unbroken and tabular outline, especially the western portion of
it ; the eastern portion appears to be broken up into several
almost parallel ranges, as it approaches Akaba.

The plateau of the Tih is bounded on the east, and separated
from the valley of the Arabah, by the range of mountains
which stretches down from the Dead Sea to the head of the
Gulf of Akaba.

The best maps represent the north-east portion of this
plateau as being drained by wadies flowing into the Arabah,
which conveys their waters to the Dead Sea. But the whole of
the remaining portion is drained by the numerous branches of
the Wady el-Arish, which empties itself into the Mediterranean
Sea, about fifty miles south of Gaza, and which formed the an-
cient boundary between Egypt and Palestine, under the name of
the Biver of Egypt. Its surface presents a succession of large
undulating plains, studded with low mountain ranges, which
appear generally to run from south to north ; its rocks are com-
posed chiefly of calcareous limestone, which in some places is
very rich in Echinodermata and other fossils ; its plains are
hard and pebbly, often covered with numerous flints of dark
colour, which contrast strangely with the glaring whiteness of
its mountains. The southern and more elevated portion of this
plateau is singularly barren, but as it slopes northwards, and
the branches of the Wady el-Arish increase in number and size,
the vegetation increases in proportion. The fall being small,
the water often stands in the broad shallow wadies for a con-

THE GEOLOGY OF SINAI.

13

sideTable time, and leaves large tracts of alluvial deposit, which,
if properly cultivated, would }deld an abundant harvest. I have
seen several acres of this soil ploughed up for corn within a
few miles of Nukhl, though in consequence of the dearth of
rain it had not been sown ; from this point northwards every
day’s journey shows a visible increase in the amount of vege-
tation, and before reaching the ruins of el-Abdeh, the country
assumes the character of downs, the low-rounded hills being
covered with tufts of grass : the wadies in this portion of the
desert abound in the spring with anemones and other flowers,
some of which the Englishman may recognise as garden friends
in his own country ; and the ruins of walls built across the
watercourses to support terraces, and heaps of loose stones
gathered from the fields, give evidence of cultivation having
been carried on in ancient times to a considerable extent.
This district of the Tih has evidently changed much since
the commencement of our era. Ruins of considerable towns
mark the former existence of a large population, where
now a few wandering hordes of Bedouins are alone to be
found. The desert has again claimed as its own the land that
was formerly rescued from its grasp. Unchecked, it still ad-
vances, slowly indeed here, but more rapidly and steadily along
the coast of the Mediterranean and on the borders of the
Isthmus of Suez, under the resistless influence of overwhelming
sand- drifts. Of the supply of water in the desert of the Tih, I
cannot speak with certainty ; in the southern portion it appears
to be very scanty, but is, no doubt, much more abundant in the
more mountainous districts on the north-east, and in the basin
of the Wady el-Arish. ~

We turn now to the southern division of the peninsula, which
includes the granitic and sandstone districts, and the large plains
which extend along the shore of the Gulf of Suez — that is, the
whole of the country to the south of the mountain ranges of
Jebel er-Rahah and Jebel et-Tih. The limestone of the Tih
is separated from the mountains of the Tur (the name given by
the Arabs to the mountainous district in the south of the penin-
sula) by a belt of sand called the Debbet-er-Ramleh, which
stretches across nearly the whole breadth of the peninsula; and
this is the only tract of sand which is to be found in this district.
My readers will have learned by this time that a desert is not
necessarily a level expanse of sand, almost entirely devoid of
vegetation. Such in deed are many of the deserts of Africa, perfect
“ seas ” of sand, as they are sometimes called by the natives ; but
this popular idea of a desert is for the most part a very erroneous
one, and has been the cause of great misunderstanding as to the
features of “the Desert of Sinai.” The district of the Tur is es-
sentially a mountainous region, so much so, that one of the great

14

POPULAR SCIENCE REVIEW.

difficulties which travellers have met with has been to find in it a
plain or valley sufficiently large to contain the tents of the Israelite
host. It has been called “ the Alps unclothed and next to the
wild grandeur of its mountains, the most striking peculiarity that
meets the eye of the traveller who has just left the rich valley
of the Nile is the absence of vegetation, and the barrenness of
its rocks. A very remarkable succession of plains extends along
the whole of the western coast of the peninsula from Suez to the
southernmost point of Eas Mohammed. The most northern of
these plains, the ancient wilderness of Etham, or Shur, is about
seventy miles long, and from twelve to fifteen miles broad, being
bounded on the east by the range of Jebel er-Eahah, which has
already been described. This plain may be said to extend as
far south as Jebel Hummam, a ridge of calcareous limestone,
which forms a bold promontory, cutting off all farther advance
along the shore ; about ten miles north of this point, however,
the sandstone hills between Wady Grhurundel and the spring of
Abu Suweirah interrupt the progress of the plain for a time.
The traveller who is journeying southward along the coast is
forced to make a circuit round the back of Jebel Hummam, but
south of this mountain he again arrives at a succession of smaller
plains, three in number, which together occupy a space of about
thirty miles in length, being separated from one another by low
spurs of limestone, which run down so close to the sea as barely
to leave sufficient room for a caravan to pass round them. The
first of these three plains was that occupied by the Israelites
during their encampment by the Eed Sea which is mentioned in
Numbers xxxiii. 10 ; the two latter, perhaps, were both included
in the Wilderness of Sin. The sandstone hills which enclose the
lower portion of Wady Feiran form a barrier which separates
these plains from that of el-Kaa, a plain nearly ninety miles in
length, running unbroken by any mountain until it reaches the
southern promontory of Eas Mohammed ; the northern portion
of it, however, is separated from the sea by the range of Jebel
Hemam. These shore-plains are by no means destitute of ve-
getation. That between Suez and Jebel Hummam most tra-
vellers have described as being especially barren ; but this has
been because they have taken the upper road; had they jour-
neyed along the coast, their account of it would have been very
different. The upper portion of the plain, i.e. the portion
nearest to the range of Jebel er-Eahah, is certainly sterile
enough ; but along the coast a line of low hills of sand is found,
which intercept the drainage to the sea, and have caused the
formation of a considerable tract of alluvial deposit, affording
good pasturage for the camels of the Terrabein Arabs, and
abounding with thickets of tamarisks and other bushes. The three
smaller plains which lie between Jebel Hummam and Wady

THE GEOLOGY OF SINAI.

15

Feiran are evidently flooded more or less during the winter
months by the flow of water down the numerous wadies which
open out upon them, and the less elevated parts are studded
with numerous shrubs and herbs. The northern portion of the
large plain of el-Kaa receives the whole of the drainage from
the western side of Serbal, which, aided by some local springs,
gives birth, near the little seaport of Tor, to an oasis which can
boast of the richest palm-groves in the peninsula. The southern
portion of this plain is more elevated, and consequently more
barren ; though even here occasional depressions occur along the
coast, which afford pasture-grounds for the flocks of the few
Arabs who live in the neighbouring mountains.

There are traces of extensive denudation in some of these shore-
plains : the level of the old wilderness of Etham was evidently
at one time some five or six feet higher than it is at the present
time, and the huge boulders which strew the northern portion
of it bear testimony to its having formed at some period a sea-
bed.

The general character of the shore-plains is that of a bed of
hard gravel, often covered with a coating of dark flints, which
not unfrequently present a curiously wrinkled surface, caused by
the drifting sand.

The granitic district forms a centre round which are gathered
the other rocks which are found in the southern division of
Sinai. It constitutes, as it were, the backbone of the peninsula,
and is especially interesting as containing Jebel Musa, now
generally recognised as the true Mount Sinai, and other moun-
tains which have at various times been rival claimants to that
honour, or to which tradition has attached some sacred asso-
ciation.

This district consists of rugged masses of mountains heaped
together in such intricate confusion as to baffle all attempt at
accurate description. The basins of the various wadies which
drain its waters run into one another in such a manner that it
is difficult to master the puzzle they present, or to grasp
any definite idea of the nature of the district viewed as a
whole. The wadies, deeply cut by the winter torrents through
the rocky barriers which hem them in, wind and course in every
direction. The mountains, it has been said, look as if “ they
were an ocean of lava which, whilst its waves were running
mountains high, had suddenly stood still.” It is only when he
has mounted to the summit of one of the highest central peaks,
whence he can look down upon the minor ranges dwarfed by a
somewhat distant view, and can see the larger masses arranging
themselves into more distinct groups, that the traveller realty
comprehends the leading features of the country. Mount
St. Catherine is, I believe, the highest peak in the whole

16

POPULAR SCIENCE REVIEW.

Peninsula of Sinai, being, as proved by my aneroid, 8,063 feet in
beigbt, while Jebel Um Shaumer, which has long been regarded
as the highest, is only 8,030. This mountain therefore, not
only on account of its being the most lofty, but also from its
central position, shall be selected as a standing-point from which
to take a general view of the granitic district.

Looking southwards the mountains are seen to form one long
ridge, which extends to the very southernmost point of the pe-
ninsula : perhaps the shape of the mountains may be thought
almost too irregular to take the name of a ridge, loft}7 and
massive spurs being thrust out on either side, and bold irre-
gular peaks frequently interrupting their line ; but, speaking
in general terms, the watershed may be described as running
along a central line drawn through the south of the peninsula,
from Mount St. Catherine to Ras Mohammed, and from this
line the wadies appear to find their way more directly to the
sea on either side than is the case farther to the north. The
only mountain of any fame in this region is that of Um Shau-
mer, which lies on fhe south-west, and which has generally
been described as shrouded in mystery ; why I know not, except
it be that travellers have been more ready to listen to the
stories of the Arabs concerning a mountain which has seldom
been visited. I myself must own to having been somewhat
disappointed, after all that I heard about it, in finding in it no
mystery to unravel. Eight hours’ walk from the convent of St.
Catherine landed me on its summit ; its ascent was not more
difficult than that of Jebel Serbal ; and the mysterious noises
that my Arab tried to make me believe that I had heard were
easily traced to a rock set in motion by a herd of ibex which
bounded up the mountain before me.

The northern portion of the granitic district is more worthy
of our notice. No mountain group indeed stands prominently
forward on the east, but on the north-west is seen the massive
cluster of Jebel Serbal, which, if not the loftiest, is certainly
the most imposing-looking mountain in the whole peninsula.
We cannot, indeed, from the position in which we are viewing
it, see its various peaks ; but it owes its grandeur to its massive
form no less than to its jagged outline, and with its bold spurs
and deeply-cut wadies thrust down on the one side to the Wady
Feiran, and on the other to the broad plain of el-Kaa, it stands
unrivalled as the monarch of Sinaitic mountains. One cannot
wonder that tradition has fixed upon it as the scene of the giving
of the Law; but a closer inspection of it proves the fallacy of
such tradition. It stands in reality far removed from the plain
of el-Kaa, separated from it by a broad strip of mountainous
ground : it is a mountain which could not by any possibility
be surrounded by bounds, either on the one side or on the

THE GEOLOGY OF SINAI.

17

other. The Wady Feiran, in which the supporters of its claims
assert that the encampment of the Israelites must have been
placed, is confined and narrow; the wadies which flow into
Wady Feiran from Jebel Serbal are still less suitable for a large
encampment. In no way does this mountain seem to agree with
the account which we have in the Bible of Mount Sinai. Jebel
Musa alone, of all the mountains of the peninsula, appears to
answer the requirements of the Bible narrative ; that mountain
alone, which we look down upon from the summit of Mount St.
Catherine, lying to the north-east, close beneath our feet, stands
apart from the mountains which surround it, and rears up its
sides so precipitously, that it may indeed be described as a
mountain “that can be touched.” To the north of it extends a
broad plain, the plain of er-Rahah, enclosed by mountains on
either side, and forming a natural amphitheatre, where “ the
people could remove and stand afar off,” and listen to the won-
drous voice of Grod, which came forth from the mountain before
them. Two lofty peaks, with a deep cleft between them, imme-
diately overhang and face this plain. These form the well-
known Ras Sufsafeh. On the opposite side of the mountain rises
a yet higher peak, crowned with a little chapel, and known as
the summit of Jebel Musa ; yet this peak stands so far back that
it is not visible from any portion of the plain of er-Rahah.
The top of the mountain between the several peaks contains a
fertile basin, which may easily be reached from three different
sides of the mountain, the easiest road being that which leads
up from the plain, at the point where it flows into the Wady
Es-Sheikh ; from this point I have reached the basin with ease
in three-quarters of an hour. The Wady Shueib on the one
side, in which stands the famous convent of St. Catherine, the
Wady Bostan on the other — rather than the Wady Leja, as has
generally been stated — separate this mountain from those on
either side of it ; and though it is not so lofty as other moun-
tains around it, its isolated position and precipitous sides rising
boldly from the plain at its foot, render its appearance far
more imposing than even that of Mount St. Catherine, which
towers above it, but loses its height to the eye, owing to its
more confined position and more gradual ascent.

The granitic district is the best watered and the most fertile
portion of the peninsula. Having the greatest elevation, it
naturally receives the largest amount of rain, which, owing to
the impermeable nature of its rocks, and the frequent occurrence
of basins, such as is found on the summit of Jebel Musa, does
not always flow off so quickly as in the other districts. There
are indeed few perennial streams to be found, either here or
elsewhere, throughout Sinai; the wadies form huge stone-drains,
which convey the water rapidly away to the sea; a thick stratum

18

rOPULAll SCIENCE REVIEW.

of stones and rubble generally fills the lower portion of their
beds, and under this the water flows unseen, except in times of
floods, or when, as in Wady Feiran, or in Wady Hibran, it is
forced to the surface by rocky barriers narrowing and contracting
their courses. It is not, however, till one wanders over the
mountain on foot, or visits the Arab encampments towards even-
ing, and sees the bundles of herbs which the men and children
bring home for the camels and goats, that one can form any just
estimation of the amount of vegetation which the rocks conceal.
The mere passer-by also is apt to overlook the quantity of
pasturage afforded by many of the wadies; this evidently
varies much, according to the season of the year, and the
amount of rain which falls in the winter months, and it is
sometimes increased in an almost miraculous manner by the
heavy rains accompanying thunderstorms at other times.

So far I have spoken only of the rocks of this central district
under the general term “ granitic I will now endeavour to
describe their geological features more accurately. They appear
to be principally composed of syenite, especially in the more
elevated districts, such as Mount St. Catharine, Jebel Musa, and
Jebel Serbal ; but hornblendic, quartzose, and porphyritic rocks
are not uncommon. The mountains are frequently seamed from
top to bottom with veins of porphyry, greenstone, and basalt,
which gives them a peculiar striped appearance, and adds much
to their beauty. This is especially remarkable on the east of the
well-known Wady Mokatteb, and in some of the wadies on the
road between Jebel Musa and Akaba. Felspar and porphyry
occur largely near Ras Mohammed, and gneiss and mica-schist
are found in the neighbourhood of Wady Mokatteb. The rock of
Moses, which lies in the Wady Leja, near Jebel Musa, and
which tradition says followed the Children of Israel in their
wanderings through the desert, is a mass of granite, with
crystals of white and pink felspar and quartz, across which
runs diagonally a vein of pure felspar, containing ten or
twelve cracks in its surface, which are said to be the mouths
from which the water flowed for the different tribes. This
rock is exactly fourteen feet in height and seventeen feet in
breadth at its broadest part. The veins which seam the moun-
tains have frequently been described as rich in metallic ores.
This appears, however, to be a mistake. Cretaceous limestone,
with numerous bands of flints, occurs in large masses in the
north-west of the Tur district, in conjunction with sand-
stone, and also on the north-west of Jebel Serbal : at the latter
spot nummulitic limestone also occurs ; near Tor and Ras Mo-
hammed a limestone of a more recent formation is found.

In several parts of the peninsula the granitic mountains are
capped by a stratum of sandstone of considerable thickness.

THE GEOLOGY OF SINAI.

19

which gives them a peculiar castellated appearance. The strati-
fication of this sandstone appears always to be perfectly hori-
zontal, and there can therefore he little doubt that it was
deposited after the upheaval of the igneous rocks; an addi-
tional proof that this was the case is also afforded by the
absence of change in the nature of the sandstone, whenever it
is found in close proximity to the granite. An equal absence
of change is also to be observed where the limestone occurs in
contact with the same rocks. The limestone apparently was
deposited previously to the sandstone ; an enormous denudation,
however, must have taken place before the deposition of the
latter ; for masses of limestone, showing no signs of upheaval,
occasionally occur at a much higher level than the sandstone ;
the thickness of the stratum of sandstone which was subse-
quently deposited must have exceeded 2,000 feet. Whether
the denudation that has since taken place has been caused by ter-
restrial or marine agency, is a question that has yet to be solved.
Considerable masses of sandstone occurring which contain a
large percentage of calcareous matter render it probable that that
rock was in process of formation while the limestone was still
undergoing disintegration. Some slight upheaval of the igneous
rocks appears to have taken place between the deposition of the
limestone and the sandstone rocks, since the stratification of the
former occasionally appears slightly disturbed, while that of the
latter, which rests upon it, retains its horizontal position ; but
this upheaval must have been very gradual and local. The
only traces of active volcanic agency which are now to be found
in the peninsula are the boiling sulphur-springs and hot caves
of Jebel Hummam, the traditional baths of King Pharoah, and
two warm springs which burst from the foot of a hill a little to
the north of Tor, and are held in great repute by the Arabs
for their medicinal powers.

The sandstone formation is especially interesting, as having
formed the great mining district of the ancient Egyptians in
Sinai, as is attested by the numerous tablets of hieroglyphics
which are found at Wady Mughara, and Serabit-el-Kadim. The
aspect of the sandstone mountains is very different to that of the
limestone and granite mountains. The limestone mountains
present a tubular summit and steep sloping sides ; the granite
mountains may be recognised almost at any distance by their
bold jagged peaks ; the sandstone mountains form with their
sides a series of steps, and are frequently pyramidal in shape.
The sandstone is generally of a reddish ferruginous colour,
though its surface is for the most part covered with a dark
brown oxide of iron, which is apparently formed by the decom-
position of the rock. The Egyptian mines which have as yet
been discovered are all turquoise mines, with the exception,

VOL. VI. —NO. XXII. I)

20

POPULAR SCIENCE REVIEW.

perhaps, of those in Wady Nusb, which I have not visited. The
turquoise appear to run more or less in veins, but their occur-
rence seems to be very uncertain ; and it is difficult to under-
stand how it could have been worth while for the Egyptians to
carry on such extensive mining operations, unless the mines
formerly yielded a more abundant return for labour than they
do at the present day. Most travellers who have visited Serabit-
el-Kadim have described two heaps of copper-slag lying on each
side of the ruined temple on the summit of that mountain, and
many have written of the copper-mines of Serabit-el-Kadim and
Wady Mughara. Specimens which have been brought from these
supposed slag-heaps prove, however, most clearly that they are
not slag-heaps at all, but merely a natural impure ore of iron
and manganese ; nor does there appear to be any copper at either
spot, excepting a thin film of silicate which occurs at Serabit-
el-Kadim. I have, however, in my possession some specimens
of undoubted copper-slag from some heaps which Major
MacDonald found near the west coast in Wady Shellal; and
also some specimens of malachite and carbonate of copper,
which prove not only that copper exists in the peninsula, but
that it has been worked and smelted.

In the neighbourhood of Wady Mughara and Wady Mokatteb
beds of siliceous brown iron ore occur in the sandstone rock,
which appear to have been worked at some period. Stone ham-
mers and flakes of flint are found round this spot, which must
either have been used by the captives of the Egyptians, who
would appear to have been condemned to work in their mines, or
by a later race — perhaps by the authors of the famous Sinaitic
inscriptions, whom I believe further research will prove to have
been a colony of the Nabathseans, established in the more fer-
tile neighbourhood of Jebel Serbal, for the purpose of working
the mines in the Peninsula of Sinai, between the years b.c. 200
and a.d. 200.

Considerable beds of beautifully crystallised salt are found
in the sandstone district, as clear and white as it is possible for
salt to be ; no fossil organisms, however, seem as yet to have been
found, except a portion of the stem of a plant, and a few other
vegetable remains. The geological changes that have taken place
in the Peninsula of Sinai in historic times I believe to have
been very small. Of the agencies which are now at work in
modifying the surface of the country, the chemical action of
the atmosphere would seem to play an important part in
destroying the ferruginous cement, which binds the particles of
the sandstone together, and thus decomposing the rock. The
wind no doubt, bearing with it the drifting sand, also aids in
the work of destruction. Frost and rain are perhaps the most
powerful agents in the more elevated portions of the peninsula.

THE GEOLOGY OF SINAI.

21

In the winter months the higher ranges of mountains are
covered with snow, and I have even seen, at the foot of Jebel
Musa, a basin of water frozen over after six o’clock in
the morning, at the very end of March. The traveller often
suffers more from the cold of the nights than he does from
the heat of the days. During December and January a large
fall of rain generally takes place, and, owing to the naked-
ness of the mountains and the steepness of the wadies, the
torrents acquire enormous power, as is testified by the size of
the boulders which are seen in their courses. The perennial
streams and springs are too few and feeble to effect much change.
The organic agencies are hardly worthy of mention, with the
exception of the coral, which must tend much to alter the nature
of the coast-line ; yet the scanty supply of vegetation which
clothes the wadies and plains aids in collecting and binding
together the drifting sand and alluvial deposits.

The question of the raised beaches, especially at the head of
the Grulf of Suez, is one of great interest. I am inclined to
believe that the shore has not risen to any great extent since
the time of the Exodus, and that the flooding of the Bitter
Lakes in the Isthmus of Suez has been effected at different
periods by the cutting of artificial canals. The explorations of
the French engineers engaged in making the Suez Canal will
perhaps aid in solving this problem. If, however, it be proved
that a considerable elevation of the coast has taken place since
the Exodus, unless we can prove that a subsequent degradation
of the shore-plains has also occurred, we shall have to alter our
opinions regarding the route taken by the Israelites on their
march to Sinai ; since large portions of these plains are now but
a few feet only above the level of the sea, and would therefore
before their elevation have been submerged. I feel confident,
however, that future explorations in the Peninsula of Sinai
will tend not to weaken but to strengthen our belief in the
sacred narrative. And I trust that, before long, a more careful
survey of the country may be made, which no doubt will place
in our hands fresh proofs of the truth of that history, and will
make us better acquainted with the features of a country which
stands almost without a rival in its interest for mankind.

22

THE PLANET MARS IN JANUARY 1867.

By RICHARD A. PROCTOR, B.A., F.R.A.S.

( Author of u Saturn and its System §c.)

OF tlie planets within the orbit of Uranus* Mars appears* at
first sight, to be the least inviting object of study to the
observer possessed of moderate telescopic power. Jupiter, from
the noble aspect of his disc, and the ever-varying configura-
tions of his attendant orbs* is among the most charming of tele-
scopic objects. With a telescope of somewhat higher power
than that available for the study of the larger planet* Saturn
bears away from him the palm for splendour of appearance, and
for the wonderful yet symmetrical gorgeousness of his attendant
system. Venus and Mercury, in a lesser degree, although both
are “ difficult” objects* yet attract the young observer, by the
lowness of the powers with which their varying phases are made
conspicuously visible. Mars, on the other hand, presents no
features which a telescope of very low power can reveal; and
even with a telescope of considerable power, some patience, com-
bined with skill and practice in observation, are required to enable
the observer to interpret satisfactorily the phenomena presented to
him. Yet it must not be forgotten that, of all the planets. Mars is
that which is in realitj the most favourably situated for telescopic
research ; or, rather, it would, not be saying too much to assert that j
Mars is the only object in the heavens whose examination is
capable of supplying an answer to some of the questions which
most largely interest the thoughtful mind. With the telescopes
yet constructed, indeed, it were too much to hope that much
exact information as to the physical condition of Mars should
be gleaned, under whatever circumstances the planet may be
observed ; nor would the simple increase of magnifying power,
which the past history of the telescope leads us to hope for and
expect, conduce greatly to the attainment of the above-named
object. But it does not seem too much to hope that some day
(haply not so far distant) the lesson taught us by Professor
Smyth’s Teneriffe experiment will be appreciated as it deserves.
Then a telescope surpassing in power an}7 yet constructed shall
be placed where alone the power of such an instrument can be

Plate H.

The Planet Mars in January 1867.

W West Lit hr

THE PLANET MAES IN JANUARY 1867.

23

efficiently exerted — where Newton long since told men that such
an instrument should be placed — far above those denser atmo-
spheric strata whose disturbances never cease, and are magnified
and aggravated by every increase of telescopic power. When
this is done, we may look in Mars for that which has long been
sought for fruitlessly upon the lunar surface — the signs of life, of
change, of progress, of decay. In one point, indeed, Mars has
already supplied such evidence ; since, as we shall presently see,
he exhibits, in regular succession, appearances corresponding to
changes well known to be taking place regularly upon our
earth.

There is another circumstance which tends to heighten the
interest with which the astronomer regards this small planet.
Its motions, watched for maiiy long }mars by Tycho Brahe, and
studied for twenty years by the ingenious Kepler, were the
means of overthrowing for ever the elaborate system of errors
and hypotheses known as Ptolemaic astronomy. They afforded
also to Newton the first hint on which he founded the law of
universal gravitation. The figure of Mars’ orbit, and the rela-
tion which that orbit bears to the orbit of our earth, rendered
the planet the most fitting, one may almost say the only
fitting, member of the solar system for the purposes Kepler had
in view.

As it is necessary for the right understanding of the appear-
ances presented by Mars at successive returns to opposition
that the nature of his orbit should be rightly understood, I
shall solicit the reader’s patience while I run as briefly as pos-
sible through the points of chief importance. This is the more
necessary because no popular work on astronomy (that I at
least have ever met with) presents with any approach to
accuracy this very important feature of the solar system. Even
that admirable and interesting work, Guillemin’s u Heavens,”
deals very inadequatel}7, though at some length, with this
question.

In fig. 1, represents the orbit of the earth, and

MjMgMgM^j that of Mars. M is the perihelion of Mars’ orbit,
which, it will be observed, is noticeably eccentric^, the centre,
being 13,000,000 miles from the sun); E is the perihelion of the
earth’s less eccentric orbit, whose centre is at C2. The arrows
indicate the direction in which both planets revolve around the
sun. The plane of Mars’ orbit is inclined at an angle of 1° 51' 5"
to that of the earth, the points marked & and £3 being those
at which the orbit of Mars intersects the plane of the earth’s
orbit ; at M and M' Mars attains his greatest distance from the
plane of the earth’s orbit, the short arrow indicating, as nearly
as possible, on the scale of our figure, the distance at which
Mars is above and below the plane of the ecliptic at these two

24

POPULAR SCIENCE REVIEW.

points respectiveh'. Of the absolute dimensions of the two
orbits, it will be sufficient to say that the greatest and least
distances of the earth from the sun are respectively 93,190,000
and 90,110,000 miles, the greatest and least distances of Mars
152,670,000 and 126,620,000 miles.

Mars takes 686*979 days in completing one circuit around
the sun ; thus it is easily calculated that the mean interval be-
tween successive oppositions is 779*836 days. Owing, however,
to the great eccentricity of Mars’ orbit, and the consequent
considerable variation in the rate of his motion around the sun,
the successive synodical revolutions of the two planets vary in
length, being greater or less according as opposition occurs
near perihelion or near aphelion respectively. The positions of
the oppositions from 1856 to 1871, marked in fig. 1, will be
sufficient to indicate this. The line of opposition travels round
in the order of the signs. After travelling twice round the
zodiac, the line falls very nearly in the position it had at
starting, such double revolution occupying thirty- three years, in
the course of which Mars has been fifteen times in opposition.

It will be obvious, from a moment’s inspection of fig. 1, that
the appearance presented by Mars, when in opposition near M,*
must be very different to that presented when he is in opposition
near M' : the distance of Mars in the former case being less
than his distance in the latter case in the proportion of about
19 to 37 ; or, in miles, the former distance is 34,140,000, the
latter 61,860,000 miles. Hence arise variations in the magni-
tude of the disc presented by the planet; and since Mars in
perihelion is more brilliantly illuminated than when in aphelion,
his apparent brightness is yet further increased. By the first
cause his brightness is increased as the squares of the numbers
37 and 19, and by the second as the squares of the numbers 41
and 34 ; or, on the whole, his brightness, when in opposition in
perihelion, is about five times as great as his brightness at oppo-
sition in aphelion. So bright does he appear, when the first
conditions are nearly approximated to, that his appearance has
caused alarm to the uneducated. Theoretically, indeed, he
ought to appear brighter at such times than Jupiter himself at
his brightest, since the disc of Mars, smaller than that of
Jupiter in the ratio of 24 to 49, is more brilliantly illuminated
in the greater ratio of 472 to 126, so that Mars should appear
brighter than Jupiter in the ratio of about 5 to 3. Jupiter,

* Owing to the eccentricity of the earth’s orbit, and the circumstance that
the perihelia of the two orbits have different positions, M is not absolutely
the point of Mars’ orbit which lies nearest to the earth’s orbit. The point
of nearest approach Recedes M by a small arc, which (were it worth while)
it would he easy to calculate.

THE PLANET MA.RS IN JANUARY 1867.

25

however, sends us more light, probably because bis atmosphere
bears large belts and masses of clouds capable of reflecting
light very perfectly, and also preventing the loss of light which
would accrue in the double passage through the planet’s atmo-
sphere. The studies of our leading astronomers and physicists
leave little doubt that the light by which we see Mars has
suffered diminution in this way to a very considerable extent.

Oppositions of Mars near perihelion occur at intervals of
fifteen and seventeen years successively. Sometimes it happens,
as in 1860 and 1862, that two successive oppositions occur at
nearly equal distances from perihelion ; it follows that the next
opposition near perihelion (in 1877) will fall midway between
these positions, or very much nearer perihelion than either of
the two others ; in other words. Mars will be very favourably
situated for observation in 1877. Much of the superiority of
perihelion-oppositions is, however, lost in our northern latitudes,
since these oppositions occur in August; and the sun being high
by day, it follows, of course, that the ecliptic (near which Mars is
always situate) is low by night. On the other hand, it is clear from
the figure that, if Mars is in opposition in midwinter, when of
course he has a considerable altitude at night, he is too near
aphelion to be favourably seen. On the whole, it follows that
the most favourable position for Mars to come to opposition in
is towards autumn (when he is near 8 of fig. 1). At this season,
while not very far from perihelion, he attains an altitude of
from 55° to 60° on the meridian. Such an opposition took place
in 1862, when very admirable views of Mars were obtained by
Messrs. Dawes, Lockyer, and Phillips, and by others of our best
observers. The opposition of 1864 was also a very favour-
able one.

But another circumstance remains to be considered. The
planet, rotating on an axis considerably inclined to the orbit of
motion (and also to the ecliptic), presents at different seasons
different aspects, not only with reference to the sun but also to
the observer on earth. At one time his north pole is bowed
down towards the sun, at another his south pole ; and the same
relations, only in a somewhat more complex order, are main-
tained with respect to the earth. If, then, the astronomer would
rightly study the peculiarities of our neighbour Mars, he must
examine the planet at oppositions occurring in every part of his
orbit. On this account, therefore, the opposition of Mars,
which takes place on January 10, 1867, although occurring
when he is not very far from aphelion, is not to be on that
account neglected. It happens, indeed, that, for the study of
the northern hemisphere of Mars, this opposition occurs, on the
whole (that is, combining considerations of distance, altitude.

26

POPULAR SCIENCE REVIEW.

and extent of presentation of the northern hemisphere), in about
the most favourable part of Mars’ orbit.

As respects the inclination of Mars’ axis to the plane of his
orbit, and the other elements on which his seasons and the
appearance he presents to us depend, we have the determi-
nations of Sir W. Herschel. He estimated that the Martial
spring equinoctial point was situated (in 1787) in longitude
79° 28' (the longitude of Mj in the figure is 78°), the obliquity
of the Martial ecliptic 28° 42', and the inclination of Mars’
equator to the earth’s orbit 30° 18". I fear it will be considered
somewhat rash to impugn results obtained by Sir W. Herschel.
Standing, as he does, in the very foremost rank among ob-
servers, and facile princeps as an interpreter of observations,
astronomers justly look on his opinions almost as laws. Yet I
think, if we consider the nature of the observation, and the
character of the instruments used by Herschel, we must recog-
nise the fact that he attributed to his results an exactness they
were not capable of attaining to. The pictures of Mars given
by Herschel are sufficient to show that the instrument he used
was far inferior in defining power to those with which Delarue,
Dawes, Lockyer, and Phillips have examined the planet. Now,
let us see on what indications furnished by Mars (thus viewed)
Herschel founded the determinations above recorded. Deferring
to the paper in the Philosophical Transactions ,* we find that
the indications he trusted to were the motions of spots across
Mars, and the appearance or disappearance of certain bright
spots near the Martial poles. In fact, from the nature of the
case, it is obvious that no other sort of evidence was available.
The necessary observations were repeated at intervals, as the
weather permitted, and carefully reduced (on just mathematical
principles) in accordance with the motions of Mars and the
earth in their respective orbits. Now, if we consider the minute-
ness of the disc presented by Mars, the variable appearance of
the spots and points upon his surface, and the extreme difficulty
of assigning, with any approach to exactness, the period or
place at which a spot or point becomes visible on the edge of a
rotating sphere, even when such sphere is distinctly (and per-
manently) marked, we shall see that, even with the best modern
instruments, it would be impossible to determine the inclination
of Mars’ axis within two or three degrees, or the place of his
vernal equinox within seven or eight degrees. Those who are
best able to appreciate Herschel’s work as an astronomer will be
precisely those who will most clearly recognise the difficulty of
the problem he attacked. It is to be wished that some of our
modern observers would re-examine the subject. That very

Phil. Trans . 178 4, p. 241.

THE PLANET MAES IN JANUARY 1867.

27

little attention has been bestowed upon it by writers on astro-
nomy will be evident from this, — the numbers given by Herschel
are repeated not only without comment, but even without those
changes which the variations in the orbit of the planet render
necessary. Given the position of Mars’ axis with respect to his
orbit, and the position of his orbit with respect to the earth’s,
then the position of his axis with respect to the earth’s orbit
follows at once. If either of the data vary, the result will vary.
Now, the second datum has varied largely since Herschel’s time;
but no corresponding variation in the angle 30° 18' (named
above) has been introduced into our works on astronomy.

The diameter of Mars is differently estimated by different
astronomers. In Madler’s u Elements,” 4,070 miles is assigned
as the planet’s equatorial diameter. Most observers assign a
larger diameter : Hind, in his “ Astronomy,” giving the planet
a diameter of 4,500 miles. These estimates are, of course,
founded on the old estimate of the sun’s distance. It seems
probable that 4,150 miles on that estimate, or 4,000 miles, if
the modern reduced estimate of the sun’s distance is accepted,
is not very far from the true diameter of the planet. In other
words, the linear dimensions of Mars are about one-half those
of the earth, or twice those of the moon ; more roughly, his
surface is about one-fourth that of the earth, or four times that
of the moon; and, yet more roughly, his volume about one-
eighth that of the earth, or eight times that of the moon.

Herschel determined the compression of Mars at ; modern
observers greatly reduce this quantity. Professor Kaiser, of
Leyden, makes the compression tA- ; Main, of the Kadcliffe
Observatory, deduced in 1862, but in some earlier measure-
ments made the polar greater than the equatorial diameter.
Mr. Dawes, apptying two modes of measurement, found, from
the first, no compression ; from the second, he found the polar
greater than the equatorial diameter. Is it going too far to say
that the oblateness of Mars’ figure is not yet determined satis-
factorily ? Probably it is too small for measurement.

Herschel made Mars’ rotation-period 24 h. 39 m. 35 s. ;
Madler gives 24 h. 37 m. 23*7 s.; and Professor Kaiser con-
siders 24 h. 37 m. 22*3 s. the true value.

Let us now turn to the opposition of January 10, 1867.
Referring to fig. 1, we see that the opposition takes place when
Mars is not very far from aphelion. The earth, also, being
very near perihelion, is drawn as far away from Mars’ orbit as
this cause permits her to be. Mars is nearly at his greatest
distance from the plane of the ecliptic. Thus the distance of
Mars from the earth is very much greater than at the oppositions
of 1864, 1862, and 1860. In fact, the absolute distance of
Mars will be no less than 58,500,000 miles, much nearer to his

28

POPULAR SCIENCE REYIEW.

greatest than to his least limit of distance. Thus, whereas the
greatest diameter Mars can present is no less than 24", and his
least only 13‘3", his apparent diameter on January 10 will be
only 14-0". There is an error, by the way, in the Nautical Al-
manac on this point ; and not a single error, due to an accident
or misprint, but an error running through the whole series
of apparent magnitudes for several months. In fact, a larger
diameter is attributed to the planet than at the opposition of
1864, an error which a moment’s inspection of fig. 1 is sufficient
to correct.*

Next let us consider what is the polar presentation of Mars
at the approaching opposition. Eeferring to fig. 1, we see that,
since Mars was at the vernal equinox of his northern hemi-
sphere when at M1? about 2J- months ago, he will be somewhat
more than one-third of the way towards the northern summer
solstice at the time of opposition. Thus the northern pole will
be turned towards the sun, and therefore towards the earth ; but
somewhat less towards the earth than towards the sun on account
of the elevation of Mars above the ecliptic. Again, when at M1?
Mars, viewed from the sun, would have appeared with his axis
apparently inclined nearly 30° to the direction of his motion ;
at the time of observation this angle will have considerably di-
minished. The actual presentation of Mars will be very nearly
that exhibited in the eight pictures of our illustrative plate.f
In these figures, details observed by Dawes in 1864, by Lockyer
and Phillips in 1862, and by Delarue in 1858, have been intro-
duced so as to accord with the actual presentation of 1867. I
have not found it an easy matter satisfactorily to reconcile these
designs ; neither, indeed, is it to be assumed that Mars presents
at all seasons identical features. It is found, in fact, that, besides
periodic changes in the dimensions of those two white caps near
the polar regions which have so long been recognised as

The snowy poles of moonless Mars,

the details of other portions of his surface vary from time to
time. Spots and patches clearly made out on one occasion
appear blurred and indistinct on another — though the same

* I should have felt in doubt as to the correctness of my own calculations,
"but for (i.) the extreme simplicity of the question, and (ii.) the circumstance
that the results given in the Nautical Almanac are self-contradictory ; the
horizontal parallax (always proportional to the apparent magnitude) and
the distance of the planet being correctly given — the first less, the second
greater, than the corresponding elements in 1864.

t In these figures the horizontal line through the centre indicates the
direction of the planet’s motion. His apparent motion across the field of the
telescope will take place in a direction inclined a few degrees to this hori-
zontal line, crossing it from below upwards, and from right to left.

THE PLANET MAES IN JANUAEY 1867.

29

telescope may be used, and our own atmosphere (as tested by the
performance of the telescope on double stars) may be in a state
as favourably fitted for definition. The colour of the planet is
also variable ; the redness (compared to a faint tinge of Indian
red by some observers, and to a coppery tint by others), and the
greenish-grey tint of the darker parts of the disc, being much
more marked on some occasions than on others. Another phe-
nomenon— the paleness of the disc round the edges— is also
variable.

The variations in the appearance of Mars are clearly expli-
cable on the natural hypothesis of an atmospheric envelope,
such as that surrounding our own earth, bearing clouds and
mists over the surface of the planet. Judging by the analogy
of our own earth, we may consider that the planet’s cloud-
covering would vary in density not only from place to place
upon the surface, but, considered as a whole, from season to
season, and from year to year. It gives a high idea of the dif-
ficulty of the problem attacked by astronomers, in examining
Mars, to note that, for favourable research, we must have a fine
night upon our earth, and a clear day on Mars, combined with
favourable circumstances of distance, altitude, and presentation ;
that we cannot watch the planet through* any single Martial
year, but must be content to piece in the observations of diffe-
rent seasons of different years ; and, finally, that Mars, when in
opposition at the solstice of one of his hemispheres, is nearly
twice as far from us as when in opposition at the corresponding
solstice of the other hemisphere.

Since, in January 1867, the north Martialists are enjoying
early summer, while the southerners are entering on their
long winter, the observer on earth may expect to find the
northern snow-cap smaller than the southern ; though the
extent of the latter will not, in all probability, approach the
dimensions observed by Delarue in 1858, when the southern
hemisphere had lately passed through the full severity of the
Martial winter. The plate represents the appearances to be
looked for when an inverting telescope is used, so that the north
pole is below ; it is only necessary to invert the plate to obtain
what we are in the habit of considering the natural presentation
of such a globe.

A little consideration of fig. 1 will show that, though Mars
will gradually present more and more of his northern polar
regions towards the sun as he moves on to the positions M,m,
and M2, yet to observers on earth the north polar presentation
will not change in the same way. In fact, while Mars is
retrograding (or until the middle of February ; see map), his
north pole will be retiring so far as observers on earth are con-
cerned. Afterwards Mars will gradually present more and

30

POPULAR SCIENCE REVIEW.

more of his north polar regions towards us. In April, when
Mars will be passing through midsummer of his northern hemi-
sphere (and therefore the polar cap of his southern hemisphere
will be probably very large), the north pole will not be much
more fully presented to us than at opposition, since the earth
will have moved on beyond E. Thus observers will have a very
good view of the south polar cap — a much better view, in fact,
as respects extent of snowsurface^directed towards the earth, than
they could have if Mars were in opposition during this part of
his year. The planet, at about this time, will present his greatest
phase of gibbosity. Being much farther from the earth than in
January, more powerful telescopes will be required to reveal
minor details. In fact, his diameter will be reduced to about 7".

The path of Mars during the first five months of 1867 is ex-
hibited in fig. 2. He retrogrades below the two bright stars
Castor and Pollux, reaching his stationary point in the middle
of February. After this he advances — growing meanwhile
gradually less bright — through Gemini and Cancer, passing in
May very close to the visible cluster Prsesepe in the last-named
constellation. In no part of this course will there be the least
difficulty in tracing the planet, as at first his superior light, and
afterwards his red colour and the absence of scintillation, will
markedly distinguish him from neighbouring objects.

Observers armed with suitable instruments will have the
opportunity of aiding in the determination of that element
which may be called the fundamental element of astronomy — the
measuring-line of space — the sun’s distance from the earth.
Mars does not afford us quite such powerful means as Venus
(in transit) for the purpose in view — first, because he never
approaches us so near as Venus (in inferior conjunction); and,
secondly, because his apparent position viewed from any given
part of the earth is not determinable by a natural index-face
such as the solar disc. However, he approaches so near as to
have a sensible parallax ; and his apparent path brings him near
enough to many stars to afford very sufficient indications of
such change of apparent position. In fact, so largely has
instrumental astronomy improved, that determinations of the
solar distance afforded by Mars in opposition (especially if near
perihelion), and Venus in inferior conjunction, are more trust-
worthy than determinations obtained from the last transit of
Venus would have been (with the instruments in use in 1787)
even with far more satisfactory observations than appear to have
been actually obtained. A series of observations made by Mr.
Pogson at Madras, with an instrument very ill adapted to the
investigation, resulted in giving for the sun’s distance 88,950,000
miles, a result much nearer the distance (about 91,650,000
miles) now generally supposed to be the true one, than the dis-

Hate HI

Hg.l.

Orbit of Planet Mars &. Earth
Eig.2.;

WWest ]itiir

TIIE PLANET MAKS IN JANUARY IS67.

31

tance of 95,275,000 miles, resulting from observations of Venus
at her last transits. It is to be noticed that observers proposing
to take part in investigations of this sort have two methods
available to them ; the first depending on the difference in Mars’
apparent position, viewed (simultaneously) from two distant
positions on the earth’s surface ; the second requiring no com-
parison with the work of other observers, but depending entirely
on the effects of the earth’s diurnal rotation upon the apparent
path of Mars among the stars. Observers who have sufficient
skill and suitable instruments should not fail to add their efforts
to an inquiry of so much interest. It is to be remembered that
the transits of Venus in 1874 and 1882 may fail to serve us in
the determination of the sun’s distance. A few days of cloudy
weather prevailing over two or three regions of the earth’s sur-
face would leave astronomy to await the next transit, which
occurs in 1987.

Since the above was written, I have received one of those
valuable circulars which are issued at intervals from Mr.
Bishop’s Observatory. It is prepared by Mr. Hind. I learn
from it that a determination of the position of the axis of
Mars founded by Dr. Oudemans upon the observations made by
Bessel with the Konigsburg heliometer gives results according
fairly with those of Sir W. Herschel — the assigned inclination
of the Martial axis being l-i degrees less, however, than Her-
schel’s estimate. The following numbers may prove serviceable ;
l means the angle at which the polar axis is inclined (from
uprightness) towards the earth ; jp means the apparent westerly
slope of the northern half of the axis (at the time of southing
on each night: —

i

P

i

p i

i

Jan. 7

11 11

o /

15 12

Feb. G

o /

7 9

o / 1

21 17 j

| Mar. 8

8 17

17

9 25

17 45

16

6 58

21 52

18

9 33

27

8 0

19 52

26

7 22

21 42

j 28

11 6

It will be seen from these numbers that for opposition on
January 10, the figures of the plate correctly indicate the
polar presentation of the planet.

From the same note I find that Leverrier assigns a greater
diameter to Mars even than that given in Hind’s “ Astronomy ; ”
since it results from Leverrier’s tabulated apparent diameter
that he estimates the true diameter of Mars at 5,130 miles.
This seems to be the estimate lately made use of in the Nauti-
cal Almanac-, but even with this explanation there remains
much irregularity, since some of the apparent diameters given

32

POPULAR SCIENCE REVIEW.

in 1864, when compared with the horizontal parallax, assign
to Mars a diameter scarcely exceeding the earth’s radius ; ethers
give a diameter greater ; others, in 1865, give a diame-
ter less than the earth’s radius ; some, in 1866, give a dia-
meter equal to this dimension; others a diameter exceeding it
by Jq, others by others by \ ; and, finally, others by that
is, by 1,150 miles.

ON WATEE-FILTEES.

By EDWARD DIVERS, M.D., F.C.S.,

Lecturer on Natural Philosophy, Charing Cross Hospital.

<4T)EEVENTION is better than cure ” is a ffiaxim no less true of
JL foul water than it is of disease. But we cannot always act
upon it in the one case any more than in the other. Eiches cer-
tainly may do much in preserving health, but then there are the
many circumstances affecting it which are beyond human control
and the force of riches. To a much greater extent, however, can
money ensure the obtaining and preservation of pure drinking-
water. Nevertheless, besides the comparatively narrow cases of the
voyager and the explorer, there is one case which directly con-
cerns millions where money practically fails to procure a pure
supply of water; and that is the case, which applies to the
dweller in London and so many other large towns, of living in a
rich community the corporate authorities of which fail to see
money’s worth in an expenditure to procure wholesome drinking-
water for their people. It is surely a terrible consideration, that
thousands may be slaughtered in a few weeks by a water com-
pany through the shortsightedness and parsimony of those who
have accepted the high office of guardians of the public health
and wellbeing. That thousands have thus been recently de-
stroyed in the east end of the metropolis is a matter hardly to be
doubted by the unprejudiced thinker. Public feeling will no
doubt before long obtain for London water fit to drink, as it has
done for a few other large towns. But, then, “ before long ”
cannot mean less than some years even in the mouths of the
most sanguine sanitary reformers, and before that it is more
than possible that impure water may bring upon the population
a decimating epidemic. Hence the importance of the object of
this article, suggested some time since to me by the editor of the
Popular Science Review . This object is in effect to assist the
reader in deciding how far means are within his reach of getting
from a foul supply pure drinking-water for himself and those
whose welfare is his more immediate concern.

By pure drinking-water, it may be perhaps necessary to state,
is not implied water actually pure. Eeally pure water is only

34

POPULAR SCIENCE REVIEW.

to be obtained with great difficulty, and so far it is fortunate that
it is not to be held as at all requisite for maintaining health. All
that is wanted, and this is what we mean by a “ pure drinking-
water,” is water free from everything of ascertained or suspected
power to induce ill-health, and — we add this as a corollary only
— from everything unpleasant to the senses and the imagination.
Consequently, guided by general experience and medical autho-
rity, the presence in small quantity of chlorides of sodium, of
calcium, or of magnesium, carbonate of calcium (chalk) or of
magnesium, or sulphate of calcium or of magnesium, either
alone or together, does not deprive a water of this title. The
presence, too, of certain gases — carbonic acid, oxygen and nitro-
gen— leaves the water still pure for drinking purposes.

Certain other substances, harmless even for some time to those
drinking water containing them in small quantity, and even health -
restoring to others, render a water notwithstanding unfit to rank
as a pure drinking-water. Take the example of hepatic waters
(waters containing sulphuretted hydrogen) and that of chalybeate
waters (waters containing combinations of iron) : however useful
these waters may prove to a valetudinarian, or harmless to any
one for a time, they are found to be hurtful on protracted use.
Other substances, again, which seem to have in themselves
nothing baneful, hardly justify a drinking-water in which they
are found being denominated pure. The reason of this will be
sufficiently intelligible. If small quantities of nitrates are found
in the water, it is in ordinary cases certain that the water has
passed through matters of animal origin, and therefore is open
to the likelihood of containing, in some succeeding supply, other
matters derived from this source highly injurious to health.
This, again, is the case with ammonia, and for the same reason ;
but the danger indicated by this substance is'even more imminent,
as water containing ammonia is almost certain to contain also
noxious matters of animal origin. All matters immediately de-
rived from animal* life are objectionable in drinking-water, be-
cause of our uncertainty as to their exact nature, and therefore as
to their effects, not to mention the offensiveness of their origin to
our ideas. And more than this, matters derived from life at all,
even though this be only vegetable, are to some extent objec-
tionable— firstly, because we cannot acquit them of all power to
do harm ; but secondly, and chiefly, because we can hardly obtain
sufficient guarantee in their presence of the absence of animal
matters also.

For though animal matters may be practically looked upon
as present if with carbonaceous (or organic) matters ammonia
or nitrates be found also, or if the carbonaceous matter be
found to be also nitrogenous, there may still be sufficient animal

ON WATER-FILTERS.

35

matter in water to do harm, and jet these evidences not be attain-
able, or, at any rate, not to an extent that can be relied upon.

However, the presence of a very little organic matter in a
water the history of which shows its impurification with sewage
to be improbable, does not make it impure for drinking
purposes. For not only is it difficult, if not impossible, to ob-
tain water altogether free from organic matter, but experience
shows that water whose antecedents can pass unchallenged, such
as the water of the lakes, may contain a small quantity with-
out harm.

One character of organic matter by which its power for evil
may be judged of, is its liability to spontaneous decomposition —
in its liability to putrefy and decay. The process of putre-
fying is indirectly a manifestation of the extent of the power
stored up in these matters when they were part of a living or-
ganism, and, what is of greater import to us at present, an evi-
dence of the power they have to do something — it may be good,
but more likely evil — to our bodies. The test of the extent to
which the bodies in water can putrefy or otherwise exhibit ac-
tive powers is their capacity of combining with oxygen. Matters
which have already combined with oxygen as far as possible, and
matters which show little readiness to combine with it at all (at
least those likely to occur in water), are both non-putrescible and
inactive apparently when swallowed. Hence the oxidisability
of a drinking-water becomes an important indication of the
likelihood of the organic matter proving injurious. The degree
of oxidisability of a water is estimated by means of the action
upon it of permanganate of potash , a substance readily yielding
oxygen. But the absence of any readily oxidisable matter in a
water is shown in another way, which it is of interest to consider
here.

We have already mentioned that a pure drinking-water may
contain oxygen and nitrogen besides other gases. These gases
in water are derived from the atmosphere, and it is found that,
in consequence of the superior solubility of oxygen in water,
twice as much is dissolved of it as of nitrogen although nitrogen
is four times more plentiful in the air. Now, if readily oxidis-
able substances are in the water, they become oxidised at the ex-
pense of this oxygen dissolved, and the result is that such water
contains less oxygen (if any) than twice as much as the nitrogen
in it. If the water contains less than a third of oxygen of
what it does of nitrogen, it may be set down as imperfectly
aerated, at least so says Dr. W. Allen Miller, and as therefore
containing readily oxidisable matters, that is, matters mostly
dangerous to health.

Of all the qualities which a water must be free from in order
that it can be looked upon as a pure drinking-water, there is one

VOL. vi. — NO. XXII. E

36

POPULAR SCIENCE REVIEW.

most essential, which, not unadvisedly we think, we have re-
frained from noticing till now. This quality is muddiness,
opalescence, or any want of perfect clearness. Of course the
matters suspended may be harmless, but even so their presence
still remains offensive to the eye. Usually, however, such waters
contain organic matter, and in most cases the solid particles them-
selves which give opalescence to the water are of this kind
and still in possession of vitality, either as fragments of living
organisms, or as perfect, organised beings themselves. Such
living particles are too probably full of power for mischief to
make their ingestion in any case safe. They may be capable of
development into human parasites ; or they may give rise, it is
believed, to specific diseases (such as cholera, supposing them to
be derived from the intestines of cholera patients through the
admission of sewage into rivers used, like the Thames, to supply
water for domestic use) ; or, during the putrefaction they have to
undergo after their vitality has passed away, they may very likely
give rise to fever and to functional disorders of the nervous and
alimentary systems.

Having thus entered at some length into what water is and
what water is not to be regarded as a pure drinking-water, we
shall now take under consideration the nature and effects of the
different forms of domestic filters provided for domestic use.
The proprietors and patentees of the various kinds of filters have,
with the exception of Mr. Lipscombe, of Regent Street, sent in,
on request, samples of the filters they offer to the public, in order
that they may be reported upon.

The primary and essential effect of a filter should be to rid
the water, passed through it of all suspended matters. But
in modern filters another effect is endeavoured to be produced,
in order to meet the requirement that water containing objec-
tionable matters in solution should be freed from them.

Many persons, when they see a water quite clear, seem to
imagine that it must be in a good state for drinking. They
should remember, however, that substances which entirely dissolve
in water do not diminish its clearness. Hence a clear bright
water may, despite its brightness, be charged with a poison or
substances more or less injurious to health, such as soluble
animal matters.

One of the most perfect filters is formed of carefully prepared
unsized paper ; but this is evidently unfitted for general use,
and is only employed in chemical operations.

Beds of material in coarse powder, pervious to water, and
unacted upon by it, such as silicious sand, form the means
usually resorted to. In other cases porous plates and blocks
are employed, such as we have presently to notice.

By forming the bed of sufficient thickness, and using

ON WATER-FILTERS.

37

material in powder of sufficient fineness, a high degree of per-
fection of mechanical filtration can be reached. The limitation,
of course, to the fineness of the powder and the thickness of the
bed is the requirement of a sufficiently rapid filtration.

Filtration through sand, however, at the best has little, if any,
effect upon the matters dissolved in water beyond that due to
the agitation of the water with air by letting it fall in drops
from the filtering-bed to the receiving vessel. For this reason,
charcoal in coarse powder has been long used in order to re-
move certain matters dissolved in water. Charcoal obtained from
animal matters alone appears to possess the power of removing
matters from solution in water to any extent. Wood-charcoal
has been, however, very much used, but with the result, conse-
quently, of only aiding in mechanically filtering the water.

There are four kinds of filters we shall now proceed to de-
scribe as essentially different from the old sand, or sand-and-
charcoal filter.

The patent moulded carbon filter consists essentially of a
block of amalgamated particles of charcoal. This block is
stated to be formed of animal, vegetable, and mineral charcoal,
all in fine powder, and incorporated together by means of pitch.
The mass, after being submitted to enormous pressure in
moulds, is heated so as to carbonise the pitch. The result is a
dense porous block. A glass tube is fixed in a hole in the
block by means of a cork, • and passes to its centre. This glass
tube then passes, by means of another cork, through the bottom *
of the chamber containing the carbon block immersed in the
unfiltered water. By this means all the water passing out of
this chamber through the glass tube must pass through the
thickness of the block from its exterior to its centre. Such, at
least, is the assertion of the proprietors of this filter. This,
however, is more than open to question ; it is tolerably certain
that some water must get through holes in the corks, and
between the block and tube and the tube itself. This filter is
stated to purify water from organic and other matters in solu-
tion. We are not able to endorse this statement as regards
organic matters in solution but to a very limited extent. We
have found that water, as supplied by one of the Thames water
companies, loses very little of its colour or smell, and a
chemical examination has confirmed these observations. As a
mechanical filter it appears to be very good. The editor of
the Popular Science Review informs me that he has found a
moulded carbon filter quite effectual in depriving a natural
chalybeate water of all ferruginous taste. A sketch of the ar-
rangement of a moulded carbon filter is shown in fig. 2, which
represents the glass sideboard filter. A cistern filter is also
constructed with a moulded carbon block, which, but only to a

38

POPULAR SCIENCE REVIEW.

limited extent, possesses some of the advantages of the arrange-
ment of Mr. Danchell, next to be described

The cistern filter sold by the London Water Purifying
Company is constructed according to Danchell’s patent. The
chamber containing the filtering material is immersed in the
water-cistern, and in whatever way the tube passing out of the

SILICATED CARBON FILTER
AND MAGNETIC CARBIDE
FILTER.

A, Silicated Carbon or Mag-
netic Carbide.

*• d, Unfiltered Water.
e, Filtered Water.

MOULDED CARBON FILTER.

b, Moulded Carbon.

d, Unfiltered Water.

e, Filtered Water.

LONDON "WATER PURIFYING
COMPANY’S FILTER.

c, Animal Charcoal.

d, Unfiltered Water.

e, Siphon.

cistern is made to go, the water during filtration passes up-
wards through the filtering material. Fig. 3 represents a sec-
tion of this filter with the delivery tube arranged as a common
siphon, passing out of the top of the cistern.

By this method of filtration, only those particles which have
not subsided before the water passes through the filter come in
contact with the filtering material, and even then in such a
position as to favour their falling away from it to the bottom
of the cistern. In the ordinary arrangement of filters all the
matters suspended in the water, whether separated by subsi-
dence or filtration, lodge in and on the upper parts of the fil-
tering material, thereby more rapidly choking up its interstices.
The pipe delivering the filtered water is closed by a tap, and
the water is only drawn off through the filter as wanted. This
arrangement is attended with both advantages and evils. The
great advantage we see in it is that the water, in quantity suffi-
cient to charge the chamber containing the filtering material,
remains in contact with this material during the period — it
may be for many hours — between the times of drawing off any
water : in consequence of this, whatever purifying power is

ON WATER-FILTERS.

39

possessed by the material is exerted for this period upon the
water, instead of during the very short time that water takes in
passing through a filtering medium. On the other hand, this
filter being constructed to yield a flow of from half to several
gallons per minute, there is the disadvantage attending such
rapid filtration that the water is subjected to the purifying
action of the material for such an exceedingly short period. How-
ever, admitting the correctness of these remarks, it is obvious
that, by only drawing off small quantities at a time — say not
more than a pint or two from the smallest size — the advantage
of the arrangement remains in full.

An advantage spoken of by the company, the importance
of which will be generally undisputed, is not, however, felt by
ourselves to be very material : for if the water is properly pu-
rified, storage in a close vessel of earthenware or glass, as is
practised in other filters, will not diminish its freshness or its
wholesomeness. An objection, in our opinion, to the cistern
arrangement, also lies in the very rapid passage through the filter
which is required to maintain the comparatively large stream
issuing from the tap, since, in order to allow of this, the me-
chanical filtration is very liable to be imperfect.

The only material employed by the London Water Purifying
Company is, we believe, animal charcoal. The high purifying
effects, therefore, of their filters is not to be wondered at,
though not the less, therefore, of the most material value.

Of the filtering capacity, in the mechanical and proper meaning
of the term, of HanchelPs filter, we cannot speak very positively ;
and we do not, therefore, challenge any statement as to its ex-
cellence or otherwise. Its purifying effects are exceedingly
striking. All the objectionable sensible qualities of water due
to organic matter are removed from the water, and chemical
examination shows that nearly the whole of the organic matter
is removed ; together with this nearly all the dissolved gases
and the dissolved chalk. The latter effects show the powers of
the filter, and render the wrater better fitted for culinary and
domestic properties ; but they are hardly desirable when the
water is for drinking, as it becomes somewhat insipid, through
the loss of its chalk and dissolved gases.

Of the two filters we have yet to notice, we have found the
one we are going next to describe to lie intermediate in power
of purifying water from dissolved organic matters. Its filtering
powers seem to be excellent, and we are inclined to think that
it admits of being more surely constructed, so as to filter effec-
tually in every case, than other filters. Our reason for so
thinking is, that being formed of a slab of the filtering material
cemented into a vessel, so as to divide it into two chambers, it
seems only necessary to select slabs free from flaws to make it

40

POPULAR SCIENCE REVIEW.

certain that all the water passes through the pores of the mate-
rial. Fig. 1 serves to give some idea of this arrangement,
only that the filtering-slab appears there as much too thick.
The slab is prepared from the coke of the Torbane Hill
mineral or coal, and is represented by the proprietors of the
patent (Dahlke’s) to owe its activity to the silica as well as the
carbon it contains.

Thames water, as supplied by the water companies, passes
through these filters with the loss of most of the colour due to
organic matters, and quite free from sensible particles of matter
in suspension. Its discoloration is not so completely effected
as it is by the animal-charcoal siphon-filter last described. A
chemical examination indicates a partial removal only of organic
matter, but then this is of the more offensive and least oxidised
portion.

The last filter we shall give some account of is the magnetic
carbide purifying filter, patented by Mr. Thomas Spencer.
This filter, represented by fig. 1, is formed of a layer of
“ magnetic carbide,” contained between two perforated stone-
ware partitions. A thin layer of sand is usually placed next
the lower partition, to increase the mechanical filtering effects
of the filter ; and, when the water to be filtered is unusually
turbid, a sponge is placed above the filtering material, through
which all the water is first strained, so that the larger quantity
of the suspended matters may be removed, and so kept from
choking the pores of the layer of filtering material. This
material, called by Mr. Spencer “magnetic carbide,” consists
essentially of black or magnetic oxide of iron, but having
also some carbon combined with it, according to the patentee.
It is prepared by heating haematite or red oxide of iron with saw-
dust in close vessels. The product is magnetic. Mr. Spencer
claims for this material the property of never losing its activity
so long as its pores do not become choked up. The same can-
not be said of animal charcoal, which, after a time, loses much
of its purifying power. We have been able to judge of the
effects of a domestic filter that had been years in use, and its
action seemed to be undiminished. . As the action of the mag-
netic carbide stands comparison with that of fresh animal char-
coal, its permanence of action places it before all other filtering
materials. Spencer’s filters appear to be little, if at all, inferior
to the animal- charcoal filters freshly mounted. Water passed
through them loses all but a very small quantity of its organic
matters. As mechanical filters they seem to be also excellent.

The magnetic carbide was employed in making the filtering-
beds of the water company at Southport, and after years of use
is still, we understand, giving every satisfaction. From its
mineral character it is suited for this purpose, whereas charcoal

ON WATER-FILTERS.

41

would be found too friable, not to mention that after a short
time it would have to be renewed. One slight objection to the
action of the magnetic carbide upon water is that it is apt to
render it very slightly contaminated with iron if the water con-
tains much carbonic acid.

It will thus be seen that, in the magnetic carbide filter of
Spencer, the cistern-filter of Danchell, and the silicated carbon
filter, we may possess with tolerable certainty the means of
freeing water from matters injurious to health. The uncertainty
lies in the fact that the particular filter used by a person may
be imperfect as a mechanical filterer, and may have become in-
efficient as a purifier from dissolved organic matters, unless, as
regards the latter point, it be a Spencer’s filter, and have only
been used with water of tolerable clearness (such as that sup-
plied to London), and not largely charged with carbonate of
lime in solution. Hence arises the propriety of having a
filter examined after being placed in a house, in order to test its
efficiency. This ought to be done by the filter-sellers.

42

OUR FRESHWATER ENTOMOSTRACA, SHELL-
INSECTS, OR WATER-FLEAS.

By W. BAIRD, M.D. F.L.S.

OUR freshwater lakes, ponds, and ditches swarm with an in-
finity of living creatures, and even our slow-running sluggish
streams and rivers afford a safe habitation for numberless mi-
nute species of the animal creation. Conspicuous amongst these
denizens of the fresh water are the little Crustaceans known to
zoologists by the name of Entomostraca.

Distinguished, as a great majority of them are, by possessing,
or appearing to possess, a single large eye, the species which
were known to Linnaeus were almost all included by that cele-
brated naturalist under the simple term Monoculus.* The
most eminent, however, of all the succeeding earlier historians
of these little creatures, the celebrated Danish zoologist, Otho
Fridericus Muller, looking at them from another point of view,
conferred upon them a different name. The singular appearance
which most of them present, viz. annulose animals or insects
covered with what appears at first sight to be a bivalve shell,
supplied to him the appellation of Entomostraca,! or shell-insects ,
a name by which they are still known, and which has been
retained by almost all succeeding authors.

A great many of these shell-insects are natives also of the
waters of our seas and estuaries, and play a by no means de-
spicable part in the economy of creation. At present, however,
we limit ourselves to the inhabitants of our fresh waters ; and,
indeed, the interest attached to their history is great. Muller’s
description of them is in elegant Latin, and his work J is still
one of the most interesting memoirs in natural history. Jurine,
in his work on the Freshwater Monoculi of the neighbourhood
of Geneva, tells us that he had studied these little creatures for
many years, and that each succeeding year only added to the
interest he felt in them.

* Monos (Greek), one ; oculus (Latin), eye.
t Entomos (G.), an insect, ostrakon (G.), a shell.

X Entomostraca, seu insecta testacea, quae in aquis Daniae et Norvegise
reperit, descripsit et iconibus illustravit Otho Fridericus Muller. Lipsice et
Hamits, 1785.

;:4k*

Our "f res'll water Entornostr

Wesr m

OUR FRESHWATER EUTOMOSTRACA.

43

These minute shell-insects, then, or Entomostraca, belong to
the great class Crustacea , and, though possessing extreme deli-
cacy of structure, are formed on the same model as our shrimps,
prawns, and lobsters. They have a brain, or several nervous
knots, called ganglia , which supply its place ; a heart, which is
generally placed near the centre of the body, and propels the
blood or circulating fluid to the different organs ; and gills, or
branchiae , attached either to the feet or organs of mastication, by
means of which respiration is carried on. They are all aquatic,
and in general are covered externally by a shell, or what is
called a carajpace , formed of one or two pieces, of a flexible
horny texture. They have more or less well-formed organs of
mastication, and have jointed ciliated feet, well adapted for the
purpose of swimming. These creatures vary much, however, in
their general appearance, and have been divided by naturalists
into several large groups, or orders. We append a short de-
scription of these in a note below. * * * §

* Our freshwater shell-insects, living free and unattached in the water,
are all contained in two great divisions, or legions, called —

1. Braxchiopoda,* Branchiopods ; which are characterised by their
having many gills or branchice, which are attached to the feet , these latter
varying in number, in some being very numerous, and only formed for swim-
ming ; by their body being either naked or having an envelope in form of a
buckler, in some enclosing only the head or thorax, in others the whole
body ; and by their mouth being furnished with organs fitted for mastication.

II. LoPHYEOPODA,f Lophyropods ; which are characterised by their having
few gills or branchice , which are attached to the organs of the mouth ; by having
few pairs of feet, and these serving chiefly for purposes of locomotion ; by
their body having always an envelope, either in form of a buckler enclosing
the head and thorax or in shape of a bivalve shell enclosing the whole
animal ; and by their mouth being furnished with organs of mastication.

The first legion, the Branchiopods, are divided again into two orders : —

. 1. Phyllopoda,! Phyllopods ; which are characterised by their having
the body either naked or having only the head and thorax covered by the
carapace ; by having numerous pairs of feet, the joints or articulations of
which are foliaceoits or leaf-like, and perform the part of organs of respira-
tion, instead of locomotion ; and by their feelers or antennae being small and
not adapted for assisting the animal in swimming.

This order contains the Apus and Chirocephalus.

2. Cladoceea,§ Branched-horned Water-Fleas, which are characterised
by their having the whole body, with the exception of the head, which is
distinct and projecting, entirely enclosed within a carapace formed of two

* Branchia (G.), gills j pous (G.), a foot,

t Lophurus (G.), having stiff hairs ; pous (G.), a foot.

| Phyllon (G.), a leaf ; pous (G.), foot.

§ Klados (G.), a branch ; Keros (G.), a horn.

44

POPULAR SCIENCE REVIEW.

The freshwater Entomostraca, as we have at the commence-
ment observed, are to be found in great numbers in our ponds
and ditches ; and though they may be observed during most
months, it is in summer and autumn that they are to be seen in
greatest abundance.

At that season of the year, then, let us seek some quiet spot,
a little way from town, and turn to “ Where the pool stands
mantled o’er with green,” and see if we can discover any of our
little friends lurking there, or playing “amid the floating verdure”
which covers the surface. A small hand-net cautiously intro-
duced, and, when removed, washed out into a small basin of clear
water, will furnish us with hundreds of the objects we are in
search of. First and foremost we see a creature of somewhat
tolerable dimensions and oval shape, transparent almost as glass,
except a rather broad dark streak running down through the
centre of its body* and a large spherical black spot placed right on
its forehead. It ; is furnished with a pair of powerful-looking
branched organs projecting from its head, which may be seen
waving to and fro in almost constant motion, so that the animal
is seldom at rest, but is perpetually moving by short sudden
bounds through the water. This is the common water-flea with
branched horns, the Daphnia pulex * (figs. 5, 6).

This water-flea is really a beautiful animal as seen through
the microscope, and its history will well repay our attention for
a short time.

valves, joined together on the hack ; by having fewer pairs of feet, chiefly
branchiform, and adapted for respiration and not locomotion ; and by having
two pairs of feelers or antennae, the inferior of which are large, branched,
and perform the functions of swimming organs.

This order contains the various kinds of branched-horned water-fleas,
the Daphnice and Lyncei.

The second legion, the Lophyropods, are likewise divided into two
orders : —

1. OsrRAC0DA,t Ostracods ; which are characterised by the animals having
the body enclosed entirely in a covering of two valves, resembling a bivalve
shell $ by the gills or branchiae being attached to the hinder jaws j and by
having only two or three pairs of feet, chiefly adapted for progressive motion.

This order contains the little creatures known as the Cypriotes, &c.

2. Copepoda,! Copepods; which are characterised by their having the
body more distinctly annulose than those of the other orders, and covered
by a buckler which encloses head and thorax ; and by having five pairs of
feet adapted for swimming.

This order contains the shell-insects known as the Cyclops, or four-horned
water-fleas, and allied genera.

* Legion, Branchiopoda ; order, Cladocera ; family, Daphnia dee.

t Ostrakon (G.), a shell,
f Kope (G.), an oar ; pous (G.), a foot.

OUR FRESHWATER ENTOMOSTRACA.

45

The body is contained within a delicate shell composed of two
valves, soldered together, as it were, on the back, and open on
the anterior margin, through which the feet and tail can be
protruded at pleasure. Posteriorly these valves are prolonged
to an acute point. The head is bold, and projecting from the
rest of the body, and the black spot on its forehead is the eye.
This organ is furnished with powerful muscles, so arranged as
to allow it to possess a semi-rotatory motion upon its axis, and
is compassed about with numerous glassy-looking or crystalline
lenses. The two large branched organs projecting from the
head are called the large antennae ; and it is by means of these
organs that the water-flea is able to propel itself through the
water. The mouth is situated near the base of the beak, and is
furnished with two mandibles and one pair of jaws. The broad
dark streak running down through the body is the stomach,
which we see curved at its upper part into a complete arch, and
then running nearly straight downwards through the body till
near its extremity, when it curves suddenly again in an upward
direction. This part of the animal and the remaining portions
of the body can be seen quite clearly and distinctly through the
carapace or shell. The body proper terminates in a broadisb
plate, which ends in two horny-looking hooks ; and this part
forms what is called the tail, and, with the greater part of the
body, can be extruded beyond the valves at pleasure. The legs
are five pairs in number, and even when the little creature is at
rest, these organs may be observed to be in constant motion,
which communicates an undulatory motion to the water, esta-
blishing a regular current which carries the particles destined
for its food towards the mouth. The chief use, however, of
these organs is for respiration, and for this purpose they are
well adapted by their having a branchial plate attached to them
furnished with long plumose setae or bristles, and which answers
the same purpose as the gills of the crabs and lobsters, &c.

In the females (fig. 5), the ovaries are internal, are placed
along the sides of the stomach, and show their situation by the
eggs appearing there in the shape of small round pellucid
globules.

In this pool in which we have found these daphniae, they are
all clear and transparent ; but at times, and in other situations,
they become of a red colour, and, when very numerous, as they
sometimes are, they impart, at first glance, a red hue like blood
to the whole pond in which they are observed. When this was
first noticed, it was looked upon as a bad omen, and some
calamity was prophesied as sure to follow. I have often seen
this phenomenon in horse-ponds and such like places, and have
often been surprised to see suddenly large patches of the pond
become of a ruddy hue, like as if a quantity of the red rust of

46

POPULAR SCIENCE REVIEW.

iron had been mixed with the water, or as if a current of blood
had flowed into it.

There are two or three facts connected with the history of
these water-fleas which are marvellous to our comprehension ;
and as these animals are easily preserved alive, it is no very
difficult matter to watch the various processes and witness the
extraordinary facts with our own eyes.

The first thing which strikes the investigator into their
history is the wonderfully prolific nature of the little creatures.
They give birth to young a great many times during the short
season of their lives, and some of the larger species have as
many as forty or fifty eggs and upwards’ in their ovary at once.
About ten days after birth, the young ones begin to have eggs !
and it is probable they continue to produce fresh broods all the
summer through at frequent intervals. The males (fig. 6) are
very few in number compared with the females, and it appears
a well-established fact that, when a female once becomes im-
pregnated, her fecundity continues for life without any further
intervention of the male, and this fecundity is transmitted to
her female descendants for many successive generations. I have,
by isolating them immediately after birth, proved the fact that
the young daphnia, born during the early summer, does not
require the access of the male to become a mother, and have,
by repeatedly isolating the young as soon as they were born,
succeeded in following up the successive generations as far as
the fourth, and Jurine has followed them up as far as the sixth
without any diminution of their fertility. At particular seasons
of the year the mature daphnise may be observed to have a
dark opaque substance on the back of the shell. Muller, who
first noticed this appearance, for want of a better name, called
it the ephippium, or saddle, but Strauss has shown that in this
peculiar-looking substance there are gradually formed two eggs,
which have been called the winter eggs , and which, at a certain
period of the animal’s life, are thrown off its back and left to
float on the surface of the water (figs. 9, 10). In this saddle
the eggs remain during the winter, protected from the severity
of the cold, till the spring comes round, when they are hatched
by the returning warmth of the season. These young daphnise
are exactly similar in appearance to those produced direct from
the mother, and, strange to say, are equally independent of any
access of a male for fecundation. By isolating the young from
these winter eggs, I have followed up at least four successive
generations, without seeing any diminution of their prolific
nature.

Another very curious fact connected with the history of these
animals is the regular process which they undergo of moulting ,
or casting their old shell and forming a new one. Though this

foUR freshwater entomostraca. 47

process is not peculiar to these water-fleas, but is common to
most of the Crustacea, it is yet so easily observed that it be-
comes extremely interesting to watch it. It is one which in
early life is all-important to the existence of the creature, as by
the time it casts its shell the body has increased in size, and
thus it requires a new and larger habitation. Even in the ma-
ture state, it seems to be necessary for the animal’s wellbeing.
Living for the most part in water which abounds in the parasitic
freshwater Polyzoa, Confervse, &c. the shell of the daphnia soon
becomes overgrown with these organisms, which intrude them-
selves even into the interior of their carapace, thus materially
impeding the poor creature’s motions and ultimately destroying
its life.

The changes which the young undergo in their progress to
maturity are equally interesting to the observer of their habits
and manners. The mother is ovo-viviparous ; the eggs, as soon
as they leave the ovary, take their place in an open space on the
back, where they remain quite free and unattached till the time
of expulsion. In general, about the end of the fifth day, these
eggs are hatched, are tolerably well developed, and are then
launched into open day. These young differ but little in form
from their parents, except in the smaller development of their
parts (figs. 7, 8). When first expelled, the young have a long
spine at the extremity of their shell ; this, however, at first is
curled up within the shell, and it is not till they have been in
the water for a few seconds, and begun to move about, that this
tail suddenly, and with a jerk, springs out and assumes its
natural position. The hairs of the large-branched antenna may
be seen to spring forth in the same sudden manner, being pre-
viously folded up along the stem. In a short period after its
birth, the young animal is exactly like its parent, gradually in-
creasing its size, and casting its shell as it grows, till it assumes
the perfect state of the mature daphnia.

The species of water-fleas belonging to the Daphniadcc ,
hitherto described as British, are about fourteen or fifteen in
number, and may be met with in similar situations as the
Daphnia pulex.

In the same haul of the net as this in which we have found
the branched-horned water-flea, we find another entomostracon
perfectly different in shape and appearance from the last, and
possessed of four large horns or antennse. This is the Four-
horned, or smaller. Water-flea, the Cyclops quadricornis *
(figs. 11,12). _ _

The history of this little creature is equally interesting as the
preceding. The body of the animal is enclosed within a horny

* Legion, Lopbyropoda ; order, Copepodct ; family, Cyclopidce.

48

POPULAR SCIENCE REVIEW.

shell, which covers it like a buckler, but opens interiorly, to give
issue to the antennse, organs of the mouth and feet.

In this water-flea, as in the other, a distinguishing mark is
the single large eye on the forehead, which in some of the
species is of a fine ruby colour. The large antennae, or horns,
as they were wont to be called by the earlier writers, are four
in number, the two upper of which are long and generally com-
posed of numerous joints or articulations, furnished with short
hairs or setae. Immediately below the antennae is situate the
mouth, and a little lower down we see a pair of organs called by
some the foot-jaws , and by others the hands. Descending in
the body, we next see the feet, which are five pairs in number,
and are each double, or composed of two stalks arising from a
common base, each stalk consisting generally of from two to four
joints, more or less furnished with hairs. These feet, in this
species of entomostracon, are solely adapted for the act of
swimming, instead of serving, as in the preceding, for respira-
tion. In the female (fig. 11), the young are not hatched in
the internal ovary, as in the daphnia, but the ova are very
soon passed into an external ovary, which forms a little bag,
projecting on each side of the tail, and remain suspended there
for several days. In this external ovarian bag the ova remain
till they are hatched, when the sac bursts open, and the fry are
ushered forth into life. But how unlike the parent do these
young ones appear! The earlier observers of these newly-born
animals could scarcely believe their own eyes. The celebrated
microscopist Leeuwenhoek, amongst the first to notice this
fact, was so surprised at the unexpected discovery that it was
not till after repeated experiments that he became satisfied with
the result, and was persuaded that these little creatures, so
different in appearance from the parent, were actually born from
the very eggs which he had been so patiently watching.

Immediately after birth, the young animal presents the
appearance represented in fig. 13, a form so very different from
that of the adult that Muller actually could not believe his pre-
decessors who had witnessed the birth, but placed it in a distinct
genus ! It is extremely curious and interesting to watch the
transforming process which these little creatures undergo. It
takes about twenty days from the birth, more or less, according
to the heat of the weather, before they have become perfect
animals. The body gradually becomes elongated ; segmentation
takes place (fig. 14) ; the feet by degrees take on their proper
form, till at length the little creature throws off its shell, or
moults, and assumes, though not completely developed, the shape
and appearance of the adult (fig. 15). After the third moulting,
it is perfect and capable of reproducing its species. The process
of moulting is equally curious and interesting in the four-horned

OUR FRESHWATER ENTOMOSTRACA.

49

water-fleas as in the daphnise. The new shell or covering
having grown under the old one, when the process of changing
it commences, the insect fastens itself to the bottom or side of
the vessel in which it is, or to any solid object near it, so as to
give itself support ; then, by moving its limbs and shaking the
valves of the shell, it loosens the old covering, and in a short
time frees itself from it altogether.

The fertility of these water-fleas is enormous ; specimens of
the Cyclops quadricornis are often found carrying thirty or forty
eggs on each side. One female has been seen to lay ten times
successively, and one access of the male suffices to fecundate the
female for life. Jurine has watched the hatching of the eggs
and the increase of this little creature with great care, and has
given us a calculation by which we may easily ascertain the
amazing fertility of the species. He supposes, to be within
bounds, that the female lays eight times within three months,
and each time only forty eggs. At the end of one year this
female would have been the progenitor of 4,442,189,120 young!
To counterbalance this amazing fertility, they have many
enemies ; and both young and old are devoured in vast numbers
by various aquatic animals that exist in the same ponds and
ditches in which they reside, as well as by the cattle that come
to drink these waters.

The number of species of the family Cyclopidce , described as
living in the fresh waters of Great Britain, are few, amounting
to only five or six ; the greater number being natives of salt
water.

Such are the leading facts and details of the development and
history of the greater portion of our freshwater Entomostraca.
The two species we have selected are amongst the most common
of all our shell-insects, are to be found in all our stagnant pools,
ponds, and ditches, and may be easily procured and preserved
by any person who would wish to cultivate a further aquaintance
with the group to which they belong.

Many other and very beautiful species, however, are almost
equally worthy of the reader’s attention. Let us, for instance,
take a stroll as far as Blackheath. On that most delightful of
the “ lungs of London,” we find many pools and little ponds of
water, some of which are dried up during the heat of summer
and filled again in autumn, when heavy rain has fallen. We
will select this one among the gravel-pits near the gates leading
to Greenwich Park, and, throwing in our hand-net, bring it to
the brink, and wash it into our little basin. An extraordinary
sight is thus brought before us. Thousands of fine large daph-
nise, of two or three kinds, two or three species of lynceus and
cyclops, and myriads of the little bivalve shell-insect called
cypris, swim rapidly in the water. Conspicuous, however,

50

POPULAE SCIENCE EEVIEW.

amongst them all, behold a creature of nobler mien and appear-
ance moving stately along, a whale amongst the minnows ! It
has no shell or carapace, but is quite uncovered. It is about an
inch in length, is nearly transparent, but beautifully tinged in
parts with red and blue. The feet appear to be rather nume-
rous, are all leaf-like or foliaceous, and seem to be in constant
motion. The creature, unlike most aquatic animals, swims on
its back ; and as it gently glides along, its feet are waving to and
fro with an undulatory motion, like as when the wind passes
over a field of corn. This is the Fairy- Shrimp, the Gkiroce-
phalus diaphanus * (figs. 1,2).

This cc fairy-shrimp ” is of a slender, elongate form, and
is remarkable on account of the shape and structure of the
head. It has two kinds of antennae, one pair slender and
thread-like, the other, the lower pair, like two horns. In the
female they are comparatively small, but in the male are remark-
ably large, the basal joint of a beautiful transparent bluish-
green colour, the extremity tipped with a fine red hue (fig. 2).
Attached to this are various organs which we have not space to
describe, and which give it a remarkably complicated appearance.
Unlike the generality of the Entomostraca, the fairy-shrimp has
two large eyes, one on each side of the head, standing out upon
projecting foot-stalks. The feet are eleven pairs in number,
and serve the purpose of gills, for respiration. The body ter-
minates in a tail composed of two fin-like divisions, which are
finely feathered on the edges, and it is by this organ that pro-
gressive motion is produced. Striking the water rapidly from
right to left, it impels its body forwards, and darts away like a
fish. It is certainly the most beautiful of all our native Ento-
mostraca, and as it moves with graceful elegance through its liquid
element, forms a sight which the most indifferent observer cannot
see without pleasure. The female (fig. 1) has a large external
bag of eggs, which, when the proper time arrives, opens at the
point, and the ova are thrown out by a sudden jerk loose into
the water. These eggs vary in number from 100 to 400 at each
laying, and in about a fortnight they are hatched, and the young
issue forth into the world. Like those of the cyclops, the young
are very unlike the parent. At fig. 3, we have represented one
soon after birth. This shows a little creature consisting of two
nearly equal portions, head and body. In a short time we can
observe it moult, or cast off its shell (fig.4) ; and if we watch care-
fully, we may see this process repeated at short intervals, and
can trace the gradual development of the larval animal till at
last it appears in the state of the perfect insect.

In the neighbourhood of London, there are many localities

* Legion, Branchiopoda ; order, Thjllopoda ; family, Branchipodida.

OUR FRESHWATER ENTOMOSTRACA.

51

for the rarer kinds of Entomostraca, which are well worthy of
a visit. On the banks of the Thames, nearly opposite the vil-
lage of Isleworth, not far from Richmond, there is a famous ditch
which produces an immense number of both plants and animals.
In one spot of no great extent, a successful haul of the net
will bring to our view a multitude of Entomostraca. Amongst
these we will find a very delicate transparent creature, which
has been well described as 66 having a head all eye.” This has
been named by Muller the Polyphemus * oculus (fig. 16).
Constructed somewhat like a daphnia, this animal appears
formed of a large black head, and still larger transparent body.
The feet are four pairs in number, but do not appear to be
contained within the shell, projecting, as it were, outside of it.
The branched horns or feelers, like those of the daphnise, are
large, and serve the animal as organs of progressive motion.
The head is prominent, and appears to consist chiefly of a large
black mass placed prominently on its forehead. This is its
eye, is very large, is provided with a set of muscles which give
it a semi-rotary motion, and is beset all round the upper and
outer edges, with about twenty lucid crystalline lenses. The
large lower portion of the shell serves as a matrix, or receptacle
for containing the eggs. These are few, generally only about
six in number. This little polyphemus appears to be a very
delicate creature, and is very difficult to be kept long alive in
captivity.

In this same ditch, we find, along with the polyphemus,
numbers of little Entomostraca, belonging to the same large
group as it and the dpcphnise. These animals (the Lynceidce)
are contained within a fine transparent shell, have much smaller
horns or antennae than the daphniae, have the stomach, which
runs through the whole length of the animal, convoluted, that
is, forming one and a half complete twist or turn round itself,
and in addition to the eye, which is so prominent a figure in
this group, they have a small black spot at a little distance
in front of it. The species we have selected for representation
is the Harp-shaped Lynceus, the Acroperus harpce] (fig. 17),
a remarkably pretty creature and full of energy. Owing to the
comparative smallness of the branched horns or feelers, the
lyncei, instead of swimming by irregular bounds, like the
daphnise, direct themselves by rapid motions of these organs
straight towards the point to which they wish to go. Their
habits and economy are very much the same as those of the

* Polyphemus, the giant celebrated in the TEneid of Virgil, as having only
one eye in the centre of his forehead. Legion, Branchiopoda ; order, Clado-
cera.

f Legion, Branchiopoda ; order, Cladocera ; family, Lynceidce .

VOL. VI. — NO. XXII. F

52

POPULAR SCIENCE REVIEW.

daphniae, and they are rather numerous in species. The harp-
shaped lynceus, being very clear and transparent, is well
adapted for giving a good idea of the whole family.

There remains another group of freshwater Entomostraca to
he mentioned. This is the family Cyprididce .* The animals
of this large family are remarkably similar in appearance (at first
sight) to a small bivalve shell ; and indeed, when dried, have
often been mistaken for small molluscs.

The body is contained entirely within the carapace, which is
formed of two valves, open in front, and attached to each other
at the back by a sort of ligamentous hinge. They have only
two or three pairs of feet, which, when the animal moves
through the water, or creeps on the surface of the mud or
leaves of aquatic plants, are protruded through the open front
of the shell. This shell the animal can open or shut at
pleasure, and being rather thick and opaque, the little creature
can withdraw itself completely from view, as well as protect
itself from all its minor enemies ever ready to attack it. The
cyprides are to be found in every pond or ditch where the
water remains stagnant, and sometimes in immense numbers.
They are not so prolific as the four-horned water-fleas, already
mentioned, but in some of the larger species we can count as
many as twenty-four eggs in a single individual. As in the
Cyclopidse and Daphnise, a single impregnation lasts the animal
for life, as well as all its successive generations. The mother
deposits her eggs upon some such bodies as the leaves of
aquatic plants, and frequently various individuals combine to fix
on the same spot a mass of eggs, consisting of several hundreds.
In about four or five days, these eggs are hatched, and the young
come forth already covered with a shell, and having the appear-
ance of the perfect animal. They seem to excel all the other
Entromostraca in being able to stand the influence of drought.
When the ponds and ditches in which they live become dried
up in summer, they bury themselves in the mud as long as it
retains any moisture, and may be found active as ever imme-
diately the rain falls and again overflows their habitations.
These little creatures appear to enjoy a very lively and active
existence in their native element. Instead of being fixed to
one spot, and condemned to live in comparative darkness, like
the mussels and other molluscous animals which they resemble
in external appearance, they can open their shelly valves at
pleasure, “ enjoy the light and move about at their will, some-
times burying themselves in the mud, and at others darting
through the water, the humid element of their sphere. If they
meet any unforeseen object, they conceal themselves at once

* Legion, Lophyropoda • order, Ostracoda.

OUR FRESHWATER ENTOMOSTRACA.

53

within their shells and close the valves, so that force and address
seek in vain to open them.” We have selected one of the most
common species to be found in the neighbourhood of London
and elsewhere as our illustration, the Three-streaked Cypris
( Cypris tristriata; figs. 18, 19). The shell itself with the
animal withdrawn looks like a small bivalve shell (fig. 18), being
of an oval form and somewhat kidney-shaped. It is of a green
colour, and the hinder portion is marked with three narrow
bands or streaks of a still deeper green. To see the enclosed
animal, we must carefully break down the shell and dissect the
body out. When carefully done, it appears like fig. 19.

Such are some of the inhabitants of our fresh waters. It is
difficult in a short space to do justice to them, for —

Full Nature swarms with life ; one wondrous mass
Of animals, or atoms organised.

54

HOW TO PHOTOGRAPH MICROSCOPIC OBJECTS.
By EDWARD T. WILSON, M.B. Oxon.

« II JHCROPHOTOGRAPH ” is a very long name, recently in-
ijX troduced, to denote a very small object ; it refers to the
minute photographic reductions of portraits or views so often
shown as curiosities under the microscope. et Photomicrograph,”
on the contrary, is a name given to the photographic enlarge-
ment of a microscopic object. It is now some twenty-seven
years since the Rev. Mr. Reade, in the early days of photo-
graphy, startled the scientific world by the magnified image of
a flea, which he exhibited at a soiree given by the Marquis of
Northampton ; and since that time many persons have turned
their attention to the delineation of microscopic objects by
photography with more or less success. Instruments have been
improved, and the photographic processes have been so far sim-
plified that at the present day this new art appears likely to
attain an accuracy before unknown, a certainty in results, and a
wideness of application which will tend to place it amongst the
most useful branches of photography : not only can sections of
animal and vegetable tissues, insects entire or in part, be re-
presented with the most minute detail, but even the finest mark-
ings of Diatomacese, difficult to resolve with the best light and
the most skilful manipulation, are represented on paper with
the utmost fidelity. Microscopists have long felt the want of
some method by which their observations might be recorded at
first hand, as it were, without passing through the brain of the
artist, and receiving the unconscious impress of his mind during
the process by which the image received on the retina is trans-
ferred to the paper before him. When it is wanted, for instance,
to prove some disputed point by dissection, a good photograph
would carry conviction where the most faithful drawing would
still leave the question in doubt. Changes in growth and de-
velopment may be fixed for ever, and the minutest differences
recorded with unerring accuracy for the purposes of future study
and comparison. Much, no doubt, remains to be done before these
most desirable results can be fully arrived at, but difficulties

HOW TO PHOTOGRAPH MICROSCOPIC OBJECTS.

55

and imperfections are gradually disappearing under the hands
of Dr. Maddox, and others who have devoted much time to the
subject; and it is not unreasonable to expect that, with improve-
ment in the various printing processes, the field of microscopic
illustration by photography will be largely and indefinitely in-
creased.

In the present paper, I shall confine my remarks to the use
of artificial light in photomicrography, in the conviction that it
will eventually supersede the use of sunlight for these purposes,
and that even now it will recommend itself by its many advan-
tages to an increasing number of microscopic observers. Not
only are the arrangements simpler and less costly with artificial
light than with sunlight, but any room and any season is equally
suitable ; there are no gloomy days, no fog, no winter to inter-
fere with the operations. In the uninterrupted quiet of a long
winter’s evening, by a comfortable fire, the student of natural
phenomena has everything at his command, and is enabled to
record with a faithfulness otherwise unattainable many interest-
ing appearances which would otherwise be irretrievably lost.

But if photomicrography offers so many advantages, why, it
may reasonably be asked, is it so little practised as an art ? The
answer will probably be found in the expenses attending the
purchase of necessary instruments, and the difficulties insepar-
able from microscopic and photographic manipulations. I think
these are exaggerated, and it will be one object of these pages
to show how anyone in possession of a good microscope may at
a very trifling expense provide himself with every other requi-
site for photomicrographic work.

The arrangement adopted by Dr. Abercrombie* and myself is
rude and perhaps unsightly, but it has the merit of cheapness
in construction, simplicity, and perfect efficiency. No special
apparatus has been introduced which cannot be made at home
by the exercise of a little ingenuity and adaptation of available
resources.

Operating-Room. — Any sitting-room will fulfil all the con-
ditions of a photographic chamber. Our own work was at one
time carried on in a drawing-room. A candle shaded by a
tripod stand of yellow calico, a steady table protected by a stout
cloth, a bucket or basin, a jug and a good supply of water, will,
with the camera and necessary chemicals, go far towards furnish-
ing the requisite equipment. I shall now proceed to notice
somewhat in detail the various instruments and processes re-
quired, presuming in my readers such general knowledge of

* I cannot send these pages to the press without acknowledging the kind-
ness and assistance of my friend Dr. Abercrombie, with whom the memory
of many pleasant 1 Evenings by Lamplight’ will always be associated.

56

POPULAR SCIENCE REVIEW.

photographic and microscopic manipulation as may be obtained
in the ordinary treatises on those subjects.

Camera. — To begin with the camera — which may be described
as the dark chamber, extending from the object-glass of the
microscope to the screen on which the image is focussed. A
stout well-seasoned board, some eight feet in length by fifteen
inches in breadth, is selected as a basis of operations (A). This
is thoroughly blackened on its upper surface, and fitted with
grooves (strips of wood fixed with screws), in which the several
supports of focussing screen, microscope, and illuminating appa-
ratus, may run evenly and with accuracy. The woodwork of
an ordinary camera, or that portion of it which holds the focus-
sing glass (C), may readily be obtained without the lens, and at
a trifling cost. This is rigidly fixed to a light wooden block (B)
at such a height as to place the centre of the focussing screen
in the axis of the microscope, which is levelled horizontally, and
secured by movable clamps to a sliding board at the opposite
end of the base-board (A).

Two blackened slips of wood diverging from one another are
connected by cross-pieces, so as to form a light triangular
framework (F); and this, resting with its base on the camera (C),
and with its apex on the microscope, affords support to a double
fold of cotton velvet (Gf), which (pile side inwards) is thrown
over all. The cloth is then carefully tucked in at all points,
and its junction with the microscope effected by a layer of
cotton wool closely applied to the tube, round which the velvet
is readily secured by an indiarubber band or thread. Every
screw-head an'd reflecting portion of brass-work must be
thoroughly coated with a dead black varnish, and when the
necessary diaphragms have been inserted, the camera is ready
for use. The whole may be supported on trestles (T), or
mounted on an ordinary table; it will practically, however, be
found convenient to place it in some spare room, if such is
available, where all may be left undisturbed from day to day ;
for much time is lost, and much experimental work wasted, if
the whole has to be arranged de novo for every evening’s work.
Many improvements might be suggested on the form of camera
which I have described, such as the bellows arrangements of
Professor Pood* and of Dr. Maddox, or some modification of
Mr. Highley’s long box camera ; but these are attended with
expense, and, though they add to the convenience, do not in any
way increase the efficiency of the instrument.

Focussing Screen. — The focussing screen is best made of a
piece of good glass, coated with collodion, sensitised in the usual
way, and protected by a solution of tannin. The film thus

* Transact. Microscopic . Soc. vol. ii. N.S.

The Microscope arranged for Photography.

HOW TO PHOTOGRAPH MICROSCOPIC ORJECTS.

57

obtained gives a most perfect surface, and the finest definition
may be distinguished upon it with ease.

Microscope. — Microscopes are, of course, endless in variety,
and it would be digressing too far from my subject to enter on
any description here of those supplied by different makers. The
one we have used is a Smith & Beck, with stage, sub-stage,
and rack movements ; but a good lens is the really essential
part, all else may be supplied with the aid of a little skill and
ingenuity. Screw stage-movements, however, are of very great
assistance, and I scarcely see how they can be dispensed with
altogether when fine work is attempted with a high objective.
Supposing an instrument resembling that in the plate at H, the
whole should be mounted on a light block (U), at such a height
that, when levelled horizontally, and accurately centered, a light
thrown through the lens of the object-glass may form a rounded
disc in the centre of the focussing screen at all lengths of the
camera. If the eye-piece is to be removed — and we have always
found it advisable, even at the expense of working at a longer
camera — a tube of black velvet must be introduced into the
body of the microscope in place of the draw tube, together with
one or two diaphragms (D) cut out of tin, and carefully coated
with black.

No care should be spared in obtaining perfect blackness
within the camera. Stray light from any reflecting point will
give the greatest trouble ; and this source of fogging may
escape notice for a long time if all is not made secure before the
commencement of regular work.

The Lens. — I have said that the lens should be a good one, and
some explanation will be needed on this point, for the qualities
most prized by the microscopist are not always those which are
most useful in photographic work. For the latter, the older lenses
with small angle of aperture and great penetration are for all
ordinary objects preferable to the most recent improvements
with large angle and perfection of definition in a flat field : a
fair definition over the whole picture is of more value than the
minutest detail over a few isolated points which happen to lie
in a common plane. Keeping this in view, it will further be
advisable to use the lowest power which will give the required
detail, and to sacrifice light by lengthening the camera rather
than run the risk of losing the penetration which the lower ob-
jective will afford. But whatever the lens, it will still be im-
perfect for photographic purposes, as I shall presently explain,
and this imperfection will be found to vary inversely as the
power of the objective. In passing through an ordinary lens,
the component parts of a simple ray of light are variously re-
fracted— the chemical or actinic rays of the spectrum, violet
and invisible, being brought to a focus at a point nearer to the

58

POPULAR SCIENCE REVIEW.

Jens than the yellow and red rays which make up the visual
image seen upon the screen.

This chromatic aberration must, of course, he corrected in the
best objectives by the proper combination of glasses with varying
refractive powers; but, unfortunately for photographers, they are,
invariably in the lower powers, overcorrected to compensate for
some undercorrection in the eye-pieces, so that, instead of finding
the actinic focus at a point nearer to the lens than that of the
red and yellow rays, it is actually thrown farther off, and lies at
some point beyond the image which is focussed on the screen.

Various plans have been suggested for readjusting this differ-
ence, but the simplest and least costly will be presently de-
scribed under the head of “ turning out,” by which the distance
between the visual and actinic focus is accurately ascertained
for each separate lens.

Coarse Adjustment, — When there are two adjustments attached
to the microscope, it will be found advisable to reserve the coarser
exclusively for focussing the object, and to leave the fine screw
for the equally delicate operation of compensating for the differ-
ence of visual and actinic foci. Of course, in a long camera both
screws are far beyond the reach of the hand when focussing ;
but a very simple contrivance will enable the operator to obtain
the greatest possible delicacy. A stout brass wire (K) is bent
round at one end so as to clip firmly the milled head of the
coarse adjustment (I) ; a lever is thus obtained, the distal end
of which will move through an appreciable space for the
minutest variation of focus. To this lever, a long wooden rod

(L) , reaching to the focussing screen, is attached by a loop of
wire, with a small piece of perforated cork below to support and
keep it in place.

Fine Adjustment — The fine adjustment will be found of great
service in recording the differences of actinic and visual foci,
especially in the higher powers when minute variations are met
with. To mark these with certainty, a small dial plate of card

(M) is attached to the body of the instrument, on which a fine
wire index bent to clip the milled screw-head of the fine adjust-
ment, and traverse with it, wfill measure the slightest alteration.

Condensers. — Passing backwards in order, the next portion
of the instrument which must be noticed is the condenser. For
some purposes we have found an ordinary bull’s-eye lens of
some 3-inch focus answer very well, but for the higher powers
a greater condensation of light is required. Eeade’s hemispheri-
cal drum is a useful form of glass ; by it the light is quickly
centred and adjusted, whilst its very complete system of stops,
throwing rays of light in any given direction, bring out the
markings of Diatomacese and other test objects with the greatest
facility. The ordinary achromatic condenser sold with most

HOW TO PHOTOGRAPH MICROSCOPIC OBJECTS.

59

good instruments may be employed, or an objective just lower
than the one in use ; and we have found this (N) with Reade’s
drum (0), the latter having its convex side to the source of illu-
mination, a most excellent combination, giving the very best
results.

Illumination . — The instrument being now complete, a source
of illumination must be decided upon. Many substances have
been used, but our own experience has been confined to oil, oxy-
calcium, and magnesium. The first is of course weakest in actinic
rays, but very good results were obtained with it up to 150 dia-
meters. Wet plates were kept moist during long exposures, some-
times reaching to forty minutes, by means of a small cup of hot
water inserted within the camera. A solar burner was employed ;
and though we have long deserted it for the more brilliant mag-
nesium, it is still found useful and economical for adjusting the
light and the more lengthy process of focussing. The oxycal-
cium light gave excellent results even at the higher powers, but
the process of making oxygen was tedious, and the apparatus is
costly. I can scarcely think that it would be used now that the
more actinic light of magnesium is within the reach of every
one. After some little experience with the magnesium wire, we
have the most sanguine expectations of its ultimate usefulness.
With a proper concentration of the light, a few flashes are suffi-
cient to produce a picture even with a object-glass. The
light fails only in steadiness, and if some means could be devised
for burning the metal uniformly and at a fixed point nothing
would be left to desire. The method we have adopted for burn-
ing the ribbon is as follows : a small telescope upright of brass
(S) regulated by a screw, is fixed to a block (V) adapted to slide
on the support (U) common to microscope and light. At the
apex of the brass upright is fixed a small tin gutter or pipe of
sufficient capacity to admit the wfire easily, and directed down
wards at an angle of 45 degrees.

By this simple contrivance the point of the wire maybe raised
or depressed at pleasure, and it will be found a great assistance
in ascertaining the best point of illumination to provide a mov-
able stop of tin (P) with a pinhole aperture, which can be
attached to the boot of the condenser during this preliminary
but very important operation.

The apparatus may now be supposed to be complete ; improve-
ments will suggest themselves to anyone who seriously takes up
the art of photomicrography; but it is only after a series of trials
and many failures that certainty in the results can be obtained.
Some directions will be necessary as to the mode of using the
various instruments which have been described.

In using artificial light, many difficulties incidental to sun-
light exposures are got rid of, but new troubles arise. In place

60

POPULAR SCIENCE REVIEW.

of having too much light, barely enough can be obtained, and
no means of concentrating it are to be neglected.

I will suppose magnesium to be the light employed ; the point
at which the wire is to burn must be carefully adjusted so that
the ignited portion, about a quarter of an inch in length, may
be exactly opposite the pinhole stop (P), and give a clear and
even disc of light on the focussing screen at any length of
camera. The next point is the arrangement of the condensers,
and on this head little can be said to lighten the trouble of ex-
periment. Probably every object will require some variation in
the position of the lenses, and the best guide is the appearance
of the image on the focussing screen. It should be evenly illu-
minated, clear, sharp, and distinct in outline. With the lower
powers, probably the highest light attainable short of focussing
the flame on the object will be found to answer best; but in
representing the finer markings of Diatomacese, the light should
in general be sacrificed to definition, and this may be done either
by placing condensers and diaphragms in such a position as to
exclude all oblique rays, which give an illusive brilliancy to the
image on the screen, or by cutting off the parallel rays by a cen-
tral stop, in the one case using the parallel rays of the central
pencil only, in the other securing the more marked definition
given by oblique rays, which may be thrown in any desired direc-
tion by patterns cut out of a pill-box cover, and fixed on to the
condenser.*

Before proceeding further, it will be found convenient to
settle the lengths of camera which correspond to different
degrees of enlargement.

This may be done by placing a stage micrometer as an ob-
ject, and focussing it by means of the oil-lamp mounted in place
of the magnesium wire. The camera is then lengthened or
shortened, until the lines on the screen are found enlarged to
the required degree. 50, 100, 200, and 400 diameters are use-
ful enlargements, and the length of the camera for these, with
the several lenses, should be carefully noted.

“ Turning outT — When these preliminaries have been con-
cluded, it will be necessary to prepare the photographic mate-
rials, and ascertain experimentally the amount of correction
required for each separate lens. Much time will be occupied in
this, and the operator’s patience will be tried to the uttermost;
but no care can be too great, no attention too exact, at this
stage of the process — an error here may cause a series of dis-
appointments, extending over weeks or months of wrork. There
can be no certainty in the results unless the “ turning out” be
ascertained at once and without a shadow of doubt, and faulty

Cf. Journal Microscop. Soc. vol. vi. p. 10,

HOW TO PHOTOGRAPH MICROSCOPIC OBJECTS.

61

pictures will be the inevitable punishment of remissness in
these tedious but essential preparations.

We have seen that the object-glasses in ordinary use focus the
actinic rays behind the screen on which the visual focus is seen;
the picture, therefore, if taken at the visual focus, will be dis-
torted in a proportion corresponding to the distance between
this and the actinic focus beyond. In the higher powers this
distance is so minute that it may practically be neglected ; but
in the l^-inch, the inch, and the -J-, some alteration will have
to be made — either the focussing screen must be moved back to
the point of actinic focus before a plate is exposed, or, which
amounts to the same thing, the object-glass must be moved away
from the object, so as to bring the actinic focus into the place
of the focussing screen. This is done by means of the fine
adjustment, and it will be well to see before commencing that
the screw works readily on the slightest movement of the milled
head. Many nights’ work may be lost, and false results obtained,
through neglect of this precaution. The index-needle should be
placed at the extreme left of the dial, and moved uniformly in
one direction.

The best object to choose for the lower powers is one covered
with fine hairs at varying depths, such as the proboscis of a fly,
or the tracheal rings of the cricket’s tongue may be preferred.
A photograph is taken at the visual focus, and it will be found
that other hairs than those focussed appear sharp and defined
in the negative, whilst those which were sharpest on the
screen are hazy and indistinct. If we can recognise any two of
these, and ascertain, on looking through the microscope, how
great a movement of the fine adjustment is required to alter
the focus from one of these hairs to the other — from a hair
focussed on the screen to one actually in focus in the picture
— we shall have ascertained the correction or ee turning out ’”
for the lens in use at the time, and careful note should be
made of it, if the result is confirmed by the subsequent test of
focussing as before, altering the fine adjustment to the ascer-
tained amount, and taking a picture then which shall correspond
in all respects to the focus which had been obtained on the
screen.

This appears simple in description, but in practice it is not
so. Many experiments will have to be made, picture after
picture will have to be taken before the portion focussed on the
screen finds its exact counterpart on the collodion film. As
some slight guide to the beginner, I may mention that our 1 i-inch
Smith & Beck required of a revolution of the fine adjust-
ment-screw; a -f-inch by the same makers required of the
divisions marked on the card dial, equivalent to ^ of a revo-
lution ; a A^-inch Smith & Beck required one division on the

62

POPULAR SCIENCE REVIEW.

dial, or of a revolution ; a ± Smith & Beck required -fa of
a revolution ; a Ross’s A~inch req nired of a revolution; and in
a Powell & Leland’s -J^-inch the visual and actinic foci were
found practically to coincide. These are but rough guides. The
same powers by the same makers differ widely in this respect,
and nothing but direct experiment in each case can decide the
amount of correction required. As if these difficulties were
not sufficient, it has been asserted that each separate light re-
quires a different degree of correction; but in our experience
the difference, if any, for oil, magnesium, and oxy calcium
lights is so small that it may safely he disregarded.

Screw Collar. — One small, but not unimportant, matter still
requires to be noticed before proceeding to take the picture.
In using the higher powers, the screw collar will be found a
constant source of perplexity, and it is not easy to give any
clear rules for its adjustment. Perhaps the best plan is to
ascertain the most advantageous position with a low eye-piece
before arranging the camera, and then to take the picture at
that; of course, allowing as before for the amount of correction
which the lens requires. If the result is not quite satisfactory,
some attempt may be made with the screw collar to improve
the focus on the screen.

Of the photography I shall say little or nothing, as it does
not materially differ from the processes in ordinary use; but I
may observe that, if care, and cleanliness, and delicacy are
requisite for ordinary work, they are infinitely more necessary
where lines numbering fifty or sixty in the j-oVu Par^ °f an
have to be represented clear and distinct on the film and trans-
ferred to paper.

The operator must tread lightly, or the focus will be dis-
turbed ; he must be still, or dust will rise ; the smallest things
must constantly be attended to, or the results will not equal his
just expectations.

I shall conclude this paper by shortly going through the
process of taking a photograph of any object, say one of the
finer Diatomacese.

The camera is arranged, I will suppose, as represented in the
plate — of such length as will give an amplification of 400
diameters with the objective.

First, centre the oil-lamp. Remove carefully the apex of
the triangle (F) from the microscope, and let it rest on the base-
board at the side ; take out the velvet from the tube of the in-
strument, and insert the eye-piece. It will now be easy to fix
on the object; bring it to the centre of the field, and obtain the
best possible definition by adjustment of focus, screw-collar,
and condensers. When this has been done, the eye-piece is
again removed, the velvet tube replaced, and the whole made

HOW TO PHOTOGRAPH MICROSCOPIC OBJECTS.

63

lightproof as before. The index on the card (M) is placed well
to the left of the dial, the focussing rod is attached, and all is
ready for focussing the object. Much care and great accuracy
will be required in this process, and a small handglass will be
found very useful, taking care to look through it always in the
same direction, for the focus on the screen varies materially as
we regard it directly in a line with the light or obliquely. My
own plan is to hold the lens opposite the centre of the focussing
screen (a point marked on the collodion) at a distance of some two
inches, then, when the point of light has been caught, to move the
eye steadily backwards until the whole object is clearly shown.
The focussing rod is now pushed forwards, so as to throw the ob-
ject nearly out of focus, and gradually drawn back until the point
of sharpest definition is reached. In this way no risk is run of
■ focussing the distal side of the object. If the light is now evenly
distributed over the object, it will be well to try a few flashes of
the magnesium wire, to be sure that it is in the right position.
About a quarter of an inch of the ribbon is allowed to protrude
beyond the tin trough, and the flame of a small spirit-lamp
applied until combustion takes place. If all is satisfactory, the
index on the dial is moved on the required amount, say, ^ of a
revolution, and all is ready for preparing the plate. This should
be of stout “plate,” or flatted crown, well roughened at the edges
with a corundum file, to secure adhesion of the film during the
repeated washings it will have to undergo. One kind of col-
lodion should be selected and adhered to, preference being given
to such as will give some toughness of film.

The bath is that in ordinary use. When sensitised, the
plate is removed to the camera, and exposed to a number of
flashes from the wire, varying with the intensity of the light
on the screen and the density of the object. With a good light
and transparent object one or two will suffice, whilst in certain
cases, where oblique light is used, as many as forty or more will
be found necessary to get a satisfactory impression.

During the burning of the light, a green shade or green
spectacles afford great relief to the eyes, which, if unprotected,
are dazzled and blinded by the brilliancy of the rays.

We have used many developers, all of which answer very
well; perhaps the best is as follows: —

Protosulphate of iron, a drachm and a half ;

Powdered sugar, half an ounce ;

Glacial acetic acid, two drachms and a half ;

Distilled water, four ounces.

But it must not be left any length of time on the plate after
the image is out, or fogging will invariably make its appearance
in the subsequent processes. When the picture is confined by the

64

POPULAR SCIENCE REVIEW.

diaphragm (D1) to a portion of the plate, the corners which are
cut off should retain a transparency equal to the glass plate itself.
The occurrence of a fine dust over these portions, when the
intensifying process is complete, shows that the developer has
been allowed to remain too long, or that the arrangement of the
condensers and diaphragms has allowed too much interference of
oblique rays in the picture.

When the image is fully out, and cleared by hyposulphite of
soda, its merits can be fully considered. The negative will be
weak, in some cases so weak as to discourage the inexperienced
from any attempt at intensifying. But very much can be done
to supplement the deficiency of actinic power, and there is no
doubt that means will eventually be found of doing so to a
much larger extent than is now possible.

It will be found useful to vary the mode of intensifying
according to the character of the picture. If at a low power,
with plenty of light and open definition, it may be got up at
once by pyro and silver before clearing ; but if at a low light
and high power, with lines of extreme delicacy, it is best to clear
and dry the film before intensifying by daylight, with iodine,
pyrogallic, and silver. In pictures of dead black and white,
good results may be obtained by the bichloride of mercury,
followed by hydrosulphuret of ammonia, as recommended by
Col. Sir H. James, R.E. in the preparation of photozincographs
from the ordnance maps. With the 64 pyro and silver plans ”
risk is run of filling up the finer lines, and rendering the whole
picture woolly.

In printing, care must be taken to get the most perfect con-
tact between the paper and the negative, or much fine definition
will be lost in the transfer. Great pressure must be used at
the risk of cracking a few glasses from their expansion under
heat. The paper should be of the finest grain, and it may per-
haps be useful to amateurs whose time is valuable to know that
paper sensitised in a bath rendered decidedly acid by the addi-
tion of nitric acid (twenty drops to the pint of bath) will keep
perfectly well in a dry place for a week or more.

A word may be added on the selection of objects, for success,
especially in the earlier essays, will much depend on this.

Yellow or reddish tissues will generally be found very im-
penetrable to artificial light ; but I do not say that they cannot
be photographed, for even opaque objects, such as Foraminifera,
have been conquered by Professor Kingsley. Objects mounted
specially with a view to photography should have their colour,
if non-actinic, discharged by maceration in some fluid such as
chlorine water or strong liquor potassse, followed by glycerine,
varying the solution according to the chemical composition of
the object.

HOW TO PHOTOGRAPH MICROSCOPIC OBJECTS.

65

The flatness of the object is no less important than the
colour. Every part should lie as nearly as possible in one plane.
Among vegetable tissues, cells, hairs, ducts, and sections of
wood, may be mentioned as good objects. Several of the Algae,
including Diatomaceae and Desmidese, may be photographed
entire. Specimens from the higher animals would include
blood-discs, sections of bone and teeth, epidermal structures,
muscular, nervous, and fibrous tissues; whilst among lower
organisms, Infusoria, Zoophytes, Sponges and Insects, either en-
tire or in parts, will be found to supply an infinite variety of
slides adapted to the purposes of photomicrography. Much
trouble will be saved in alteration of screw collar by mounting
the Diatomaceae dry on a thin glass cover. A number of these
squares may be kept in a small box made for the purpose, and
there will be no difficulty in mounting them when required on
a perforated glass or zinc slide by means of a small indiarubber
band.

In the foregoing pages, I have endeavoured briefly, and as
clearly as the subject will admit, to describe one of the modes
by which faithful transcripts of various microscopic objects can
be obtained on paper. Of sunlight pictures I have said nothing,
but anyone who wishes information on the subject will find it
ably treated in an article contained in Dr. Beale’s “ How to
work with the Microscope.” It has been my desire to place the
art of photomicrography before my readers in the light of an
amusement and solace for evening hours, rather than as a study
demanding the labour and light of the day ; and I am not with-
out hope that some may be induced in their intervals of leisure
to take up an art at once so interesting and promising in its
results.

66

REVIEWS.

THE ORIGIN OF SPECIES.*

TO give anything like an adequate analysis of Mr. Darwin’s treatise
would require a space far greater than that at our disposal. The volume
itself is so extensive, the matter it contains is so compressed, and the argu-
ments are so condensed, that nothing short of the hook itself could lay
the facts in favour of the doctrine of Natural Selection fairly before the
public. The present edition is the fourth which has been issued since 1859 ;
and it is not merely a reprint of the one which preceded it, hut contains
numerous additions and corrections.

Whatever he the accuracy of the theory which Mr. Darwin has so ahly
promulgated, it is surprising how many distinguished men of science in all
parts of the world have given it their support and countenance. In this
country, nearly all the naturalists of repute have admitted the force of Mr.
Darwin’s opinions ; and though few of them are prepared to swear to the
truth of the new doctrine, all are ready to admit that the hypothesis of
Natural Selection has far more evidence in its favour than any other upon
the same subject that has yet been published, and that, furthermore, it is
in no way obnoxious to the facts of revelation. Among the more formid-
able opponents to Mr. Darwin’s opinions is Professor 0 wen ; at least, we
may say was, for we are at present in considerable difficulty as to the for-
mation of an idea concerning Professor Owen’s views. And yet it seems as
if the superintendent of the British Museum inclines towards the Darwinian
theory, though he does not feel that he ought to adopt it. It was only
through a recent letter, of 'Professor Owen that this mental condition dis-
played itself. In May last an important notion of Professor Owen’s treatise
on Comparative Anatomy appeared in the pages of the London Review , in
which the writer criticised with some severity, but with much justice,
Professor Owen’s comments on the theory of Natural Selection. To this
review Professor Owen replied in a long and able letter, in which, among
other statements, he remarked that, “No naturalist can dissent from the
truth of your perception of the essential identity of the passage cited with
the basis of that [the so-called Darwinian] theory, the power, viz., of spe-
cies to accommodate themselves or bow to the influences of surrounding
circumstances.” This was quite sufficient to show that Professor Owen
desired to be considered the author, or at least the suggestor, of the theory

* “ On the Origin of Species by Means of Natural Selection; or the Pre-
servation of Favoured Races in the Struggle for Life.” By Charles Darwin,
M.A., F.R.S. Fourth edition. London: Murray. 18G6.

REVIEWS.

67

of Natural Selection ; but a passage further on in the same letter places the
matter beyond all doubt ; in it Professor Owen speaks of himself as 11 the
author of the same theory (Darwinian) at the earlier date of 1850.” Clearly,
whatever be Professor Owen’s opinion as to the expediency of admitting
the new theory, he at all events desires it to be thought that he anti-
cipated Mr. Darwin in suggesting the basis of the Darwinian doctrine.
Still it is tolerably clear, as Mr. Darwin has shown, that at the very time
when Professor Owen alleges that he first suggested the essential principle
of the theory of Natural Selection, he really denied that principle in the
most unequivocal manner. The Professor states that he first gave the
scientific world the idea in a paper read before the Zoological Society in
1850 ; but the following quotation from this memoir proves that Professor
Owen at the time he put the theory forward (P) failed to understand its
very essence. In this paper he said, u We have not a particle of evidence
that any species of bird or beast that lived during the pliocene period has
had its characters modified in any respect by the influence of time or of
change of external circumstances.”

It may be gathered, therefore, from the foregoing passage that the most
formidable if not the only serious opponent of the Darwinian theory now
wavers between the old and the new hypotheses. This circumstance seems
to us of importance, because it shows that nearly all those who are capable
of forming an opinion upon the subject side with Mr. Darwin.

As to the argument in support of the Darwinian hypothesis, there is
little to be said that has not already in various forms been laid before
our readers. The great principles on which the doctrine is based
are, the tendency of what are called species to vary, and the tendency
of external conditions to destroy all those individuals which have
not sufficient natural protection. Thus, let us say that in any litter of
animals there are certain individuals provided by the law of variation with
appendages, offensive or defensive, which adapt them to the climate in which
they live, or serve to give them more protection from the attacks of animals
which prey on them, than is afforded to their fellows : it is clear that those
individuals will in the ordinary struggle for existence, which every organism
must go through, have a greater chance of protection, and hence of perpetua-
tion, than their brethren. Thus, the stronger individuals — or, in other words,
those best adapted to the conditions under which all are situ&ted — live : and
so with their successors : those of them possessing the parental characters of
adaptation in the highest degree will crush their fellows to the wall and
survive them : and thus an insignificant anatomical feature may become in
ages a very important one, and species having different characters from those
of the fortunate race become swept away or destroyed. The reader, how-
ever, will naturally raise this objection, Why do we not find intermediate
forms P This is certainly a very difficult question to reply to, but still it
can in part be answered. It may, for example, be urged that Geology affords
us to some extent a series of connecting links of great value ; and more than
this cannot be expected, for every geologist must admit that never-ceasing
denudation has annihilated the Geologic Record. Again: the period of
time required for the transition from one specific form to another is so great
as to render it quite intelligible why the connecting links exhibit themselves
YOL. VI. — NO. XXII. Gf

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POPULAR SCIENCE REVIEW.

as mere varieties. But if it be thought that at least all the connecting link 8
between any series of forms ought to be present, if not in the fossil at least
in the living state, it should be remembered that the very process of natural
selection prevents this, each succeeding variety crushing out that which
preceded it, because in this struggle for life it has the greater number of
advantages. Two elements, however^ in the argument are well sustained in:
the following passages. The first relates to the certainty of the struggle for
existence : —

(l There is no exception to the rule that every organic being naturally
increases at so high a rate, that if not destroyed, the earth would soon be
covered by the progeny of a single pair. Even slow-breeding man has
doubled in twenty-five years. At this rate, in a few thousand years there
would literally not be standing-room for his progeny. Linnaeus has calcu-
lated that if an annual plant produced only two seeds, and there is no plant
nearly so unproductive as this, and these seedlings next year produced two,
and so on, then in twenty years there would be a million. The elephant is
reckoned the slowest breeder of all known animals, and I have taken some
pains to estimate its probable minimum rate of natural increase : it will be
under the mark to assume that it begins breeding when thirty years old,
and goes on breeding till ninety years old, bringing forth three pair of young
in this interval ; if this be so, at the end of the fifth century there would
be alive fifteen million elephants, descended from the first pair.”

The second passage which we quote from Mr. Darwin, shows in a popular
manner, which must appeal to the reason of every ordinarily intelligent
person, what an enormous length of time is required in order to produce even
a moderate degree of variation, and bears forcibly upon the question which
the opponents of Natural Selection so often put, u Why do we not find inter-
mediate forms ? ”

a No one would expect to raise a first-rate melting pear from the seed of
the wild pear, though he might succeed from a poor seedling growing wild,
if it had come from a garden stock. The pear, though cultivated in classical
times, appears, from Pliny’s description, to have been a fruit of very inferior
quality. I have seen great surprise expressed in horticultural works at the
wonderful skill of gardeners in having produced such splendid results from
such poor materials ; but the art has been simple, and, as far as the final
result is concerned, has been followed almost unconsciously. It has con-
sisted in always cultivating the best known variety, saving its seeds, and
when a slightly better variety has chanced to appear selecting it, and so on-
wards. But the gardeners of the classical period, who cultivated the best
pear they could procure, never thought what splendid fruit we should eat ;
though we owe our excellent fruit in some small degree to their having
naturally chosen and preserved the best varieties they could anywhere find.

u A large amount of change in our cultivated plants, thus slowly and un-
consciously accumulated, explains, as I believe, the well-known fact, that
in a vast number of cases we cannot recognise, and therefore do not know,
the wild parent stocks of the plants which have been longest cultivated in
our flower and kitchen gardens.”

The phenomena which have been grouped together under the term Instinct
have been a powerful weapon in the hands of those who combat the Dar-
winian doctrine. It is interesting, therefore, to observe how the author deals
with this part of the subject. In trying to account for the instincts of
animals, Mr. Darwin takes two courses: first he endeavours to show how, by
the law of natural selection, what is called instinct is little more than habit.

RETIE WS.

69

arising accidentally and perpetuated ; secondly, he attacks many of the
remarkable instances of so-called instinct, and destroys much of their force.
As regards the supposition that instinct is inherited habit, there seems every
reason to think that Mr. Darwin’s view is the correct one. It is impossible
for the physical philosopher to deny that every organism has the power of
calling into play, or allowing to fall into disuse, any one of the greater number
of its parts or faculties, and it is equally impossible to deny the truth of the
proposition that such parts as are thus called into action descend to future
generations. Now, since even in the case of mental impulses, each action of
the brain must be accompanied by a corresponding change of substance, it is
clear that in this way accidental variations of mental operation may be rendered
permanent, and thus allowed to descend from one generation to another.
We may therefore in this manner account for many of the most puzzling
examples of instinct. And when we remember that animals under domesti-
cation lose most of their wild instincts and acquire a new series as the result
of artificial selection , the analogy between the effects of natural selection
and instinct on bodily structure ceases to be a difficult one.

Having analysed very fully the nature of instinctive actions, Mr. Darwin
proceeds to show that the instinct of the bee to form wax from flowers is by
no means a perfect one, for these insects will prepare the comb from various
artificial substances, such as 11 wax hardened with vermilion and softened
with lard,” “a cement of wax and turpentine,” “ oatmeal,” &c., &c. He
then makes the following remarks on the nature of the cuckoo’s instinct :

“With respect to the last point insisted on, namely, of the young
European cuckoo ejecting its foster-brothers, it must first be remarked
that Mr. Gould, who has paid particular attention to this subject, is con-
vinced that the belief is an error ; he asserts that the young foster-birds are
generally ejected during the first three days, when the young cuckoo exerts
by its hunger-cries, or by some other means, such a fascination over its
foster-parents, that it alone receives food, so that the others are starved to
death, and are then thrown out, like the egg-shells or the excrement, by the
old birds.”

We heartily wish we had space to make further quotations from this admir-
able volume ; but since we must leave the book for the present, we would
earnestly urge all our readers, whether naturalists or not, to take it up and
read it carefully. There is not a trace of special pleading in the whole
argument from beginning to end ; it is an able and honest exposition of facts
and of the inductions naturally formed upon them. It is the work of one
of the most accurate and experienced observers of the age, and cannot fail
to enlighten even those whom it cannot convince.

ELECTRICITY FOR STUDENTS.*

T\R. NO AD, the well-known author of a Manual of Electricity, now pre-
U sents the student with a closely-printed volume of more than five
hundred pages on the same subject. It is a most elaborate compilation of

* “ The Student’s Textbook of Electricity.” By Henry M. Noad, Pli. D.
E.R.S. F.C.S. Lecturer on Chemistry at St. George’s Hospital. With four
hundred illustrations. London : Lockwood and Co. 1807.

g 2

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POPULAR SCIENCE REVIEW.

the facts of electricity and magnetism, and of the theories which hare been
advanced concerning them. It is quite refreshing to go over its pages
after putting down English translations of French works on the subject,
and other works too evidently, though not admittedly, borrowed from our
continental neighbours. For in its pages we find accounts of the researches
and speculations of our own philosophers, and proper importance given to
their labours. Not that there is any confessed or apparent effort of the
author in this direction, but merely that it is a genuine compilation by a
man versed in the literature of his subject. We have often felt pained to
see English students with textbooks in their hands which leave the vast
stores of philosophical knowledge contributed by their countrymen to the
general stock unnoticed, and to know that there was no truly English
textbook sufficiently comprehensive to offer in place of them.

The work is arranged in ten parts, one of which, filling a quarter of the
volume, is devoted to the electric telegraph. The chapter in the first part, on
atmospheric electricity, will be found very interesting. In it and the chapter
on marine telegraphy, Professor William Thomson’s beautiful electrometers
are described, viz. the divided ring electrometer, the common house electro-
meter, and the portable electrometer. One important use of the first and last
of these is the testing the insulating power of the insulating coat of short
lengths of marine telegraph cable. This testing consists iu estimating the
rate at which the tension of a given charge of electricity communicated to
the wire diminishes. We shall not attempt to describe these electrometers,
but content ourselves by stating that the indicating needle is kept in metallic
communication with the inside of a charged Leyden jar, by which its at-
traction and repulsion for the two manifestations of electricity in bodies is
rendered much more sensitive and much more certain under the slight leak-
age of electricity which always takes place ; that the needle oscillates over
two half rings of brass (the divided ring), one in connection with the earth,
and the other with the charged cable or other body to be tested ; and lastly,
that for continuous observation of the electric tension of the atmosphere, the
motions of the needle are recorded by the photographic action of the light
of a lamp reflected by a mirror connected with the needle, upon a cylinder
covered with photographic paper and rotated by clockwork.

Dr. Noad gives us full accounts of even the most recent additions to our
knowledge of the subject of which he is treating. His account of the tele-
graph is exceedingly interesting. The descriptions of the many instruments
he has to notice are usually very clearly drawn out, and a comprehension of
the text is materially simplified by the introduction of numerous woodcuts.

The enunciations of fundamental principles, and the definitions of terms,
are, as a rule, usually unsatisfactory in a scientific point of view. Even these,
however, are generally compiled from the writings of others, as stated by
Dr. Noad himself. But the compiling here, as elsewhere, is a remarkable
proof of the comprehensive and philosophical way in which the author
handles his subject. And we venture to say that seldom has a scientific
writer been more happy in throwing into a treatise on a given subject the
most important of the investigations and the most correct of the views of
the workers at it. Every student of physical science will undoubtedly be
glad to possess it.

REVIEWS

71

THE ELEMENTS.*

METEOROLOGY gives promise of being as popular a pursuit as either
Natural History or Astronomy. Everybody nowadays is more or less a
meteorologist. Wherever we go we find that people begin to understand the
advantage of systematic and daily observation of the barometer and thermo-
meter, and those who appreciate the employment of the hydrometer and
ozone-test are by no means few in number. Indeed, meterology is fast be-
coming a science, and if the progress made in observation and induction
during the next ten years be equal to that which the past ten years has
brought forth, it will be a science of no mean degree of exactness. Our
readers must not, however, conclude from what we have stated that there
is much of perfection in meteorology as we yet know it. There has been
too great a tendency on the part of the general public to overrate the im-
portance of the late Admiral Fitzroy’s weather-forecasts, and to place an
implicit reliance upon all the predictions of the Meteorological Department
of the Board of Trade. This has been a serious error, for it has in some
measure prevented the degree of careful research which is the result
of an uncertainty concerning the nature of phenomena. Is it not likely
that many people gifted with scientific tastes would have selected the
pursuit of meteorological knowledge had they known how impossible it was
to frame definite predictions concerning the weather ? The real facts of the
case are : (1) that at the present moment weather-forecasts are almost an
impossibility ; and (2) that this inability to predict arises from the absence
of a sufficient number of established facts on which to frame exact gene-
ralisations. In this condition of meteorological science, we therefore look
anxiously for any work which promises to throw light on such serious
problems as those of oceanic and atmospheric currents. Not unfrequently
are we disappointed, and we are sorry to say that in the treatise before us
we have met with nothing likely to add to the facts or the inductions which
meteorologists are already familiar with. Mr. Jordan presents us with one,
amply illustrated, and, were it not for a little indulgence in the grandilo-
quent and teleological claptrap so much admired by inexperienced authors,
a really well-written volume. It, however, contains little of any practical
value. The author denies the ordinary theories of the tides, and maintains
that the centripetal force of Newton is attraction proceeding from solar
gravitation, and that the centrifugal force of the same philosopher is simply
attraction proceeding from astral gravitation. Mr. Jordan considers that
evaporation has much to do with the production of oceanic currents, but he
regards the tides as being dependent upon a larger and more complex series
of conditions. It is a matter of some difficulty to grasp the author’s views
and arguments with much clearness ; but so far as those concerning the
tides have been tabulated by him, they are as follows : — (1) The great un-
changing force which holds the water down on the earth’s surface is the

* u The Elements : an Investigation of the Forces which determine
the Position and Movements of the Ocean and Atmosphere.” By W. L.
Jordan. Yol. I. London : Longmans and Co. 1866.

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power of gravitation contained in the earth. (2) The lesser influences which
modify the position it would assume under the influence of that gravitation
alone are : — (a) the centrifugal force caused by the rotation of the earth on
its axis ; (5) the power of gravitation contained in the sun and the moon ;
and (c) the force which acts in opposition to the attraction of the sun and
the moon. Of these lesser forces the centrifugal force is, like the gravita-
tion of the earth, fixed and steady. The other lesser influences are con-
stantly changing their direction, thereby causing that constant changing of
the position of the water which forms the tides. Such is briefly Mr.
Jordan’s theory, and we leave it and its author to the consideration of our
readers.

CHOLERA TREATED BY ICE *

T\R. JOHN CHAPMAN, whose efforts to introduce ice as an important
therapeutic agent, and whose experiments upon the effects of ice in the
treatment of nervous affections are so familiar to the public and the profession,
has given us a treatise on Cholera, which certainly deserves notice. We
shall not say whether, in the present state of our knowledge of the condi-
tions under which cholera appears, Dr. Chapman is justified in putting
forward so detailed an hypothesis as that which he advocates, but we must
confess that, whatever amount of truth it may possess, his view is worked
out with a display of logical reasoning, formidable facts, and erudition such
as is seldom met with in medical essays. In noticing the work before us,
we must do so from two aspects ; we must first consider Dr. Chapman’s
explanation of the cause of cholera, and, secondly, we must examine into the
character of his mode of treatment. The first is by far the most interesting
point. Dr. Chapman thinks that the chief cause of cholera is external heat,
which, by acting upon the nervous centres, increases the quantity of blood
supplied to them, and thus brings them more powerfully into action. It
is known from the experiments of Bernard and other writers that, when
the sympathetic nerve-centres are stimulated, those of their branches
supplying the bloodvessels cause these latter to contract. Another
physiological fact is that, when a secreting surface has its ordinary blood-
supply slightly diminished, it throws off a larger quantity of fluid than
usual. Connecting these two well-known laws, Dr. Chapman frames an
argument somewhat in the following manner : Heat applied to the back

stimulates the sympathetic nerve ; stimulation of the sympathetic^ causes
contraction of the bloodvessels of (among other parts) the intestinal canal ;
the diminution in supply of blood thus produced causes increased secretion
of mucus, aud finally increased secretion of mucus brings on diarrhoea.
Thus we see the conclusion is very excellently reasoned out ; but is Dr.
Chapman quite sure of his premisses ? Has he ever produced true choleraic
symptoms in animals, let us say, by the application of heat to the spine P

* u Diarrhoea and Cholera : their Nature, Origin, and Treatment through
the agency of the Nervous System.” By John Chapman, M.D. M.R.C.P,
M.R.C.S. 2nd edition, enlarged. London : Triibner & Co. 1866.

REVIEWS.

73

Has he been able to adduce a single undoubted instance of cholera produced
by the action of external temperature ? If not, then be is hardly warranted
in denying the evidence already accumulated in support of the contagion
and poison theories. The next point to be noticed in Dr. Chapman’s book
is that which refers to his treatment. The author, believing that the action
of heat in the spine is the cause of cholera, considers that ice applied over
the sympathetic centres is the only reliable remedy in cholera cases. Of
course, if we admit Dr. Chapman’s conclusions as above, we cannot deny the
truth of his proposition that ice is the sheet-anchor of remedial agents in
cholera ; but, as we have already said, we do not think that the author’s
argument rests on a sound basis. However, it is interesting to see what are
the results of his practice, and we beg to refer our readers to Dr. Chapman’s
volume for a most conscientious report on this part of the subject. We
cannot say that the proportion of recoveries is anything very surprising, but
our readers will judge or themselves on this point. One thing must be
admitted; that of the hundred and one treatises on cholera which have been
published during the past year, Dr. Chapman’s is at once the most interest-
ing, the most scientific, and the most scholarly.

MODERN CHEMISTRY EOR STUDENTS.*

TO anyone but an eager follower of the study of chemistry, Dr. Frank-
land’s book must appear very repulsive ; and did we not know what
numbers there are devoted to this wondrous science, we should quake for
the result to the enterprising publisher who issues it.

The object of the work is to free the attendant at the Professor’s lectures
from the necessity of taking notes of the matters brought before his notice,
and so to prevent distraction from much that is being uttered, in order to
have a record of the rest. All descriptive matter — at least nearly all — is
omitted, as being within the student’s reach in other treatises ; and the work
mainly consists of explanations, in symbolical language, of the chemical
changes by which bodies are produced and by which they pass into others.
The modern atomic weights are employed, but the notation is peculiar to
Dr. Frankland, though now before the chemical world, to a certain extent at
least, for some years. In the symbolical formulae of a body, our distin-
guished author endeavours to represent at a glance, to the initiated, a
synopsis of its chemical properties. The formulae are also expressions of
ascertained facts concerning the body, and but little hypothesis. The typical
formulae of Gerhardt have been found valuable to chemists, because they
represented, to a considerable extent, the number of atoms of one element
necessary to meet the combining power of another, thus furnishing an
explanation of the faculty of atoms of becoming linked into complex groups.

* u Lecture Notes for Chemical Students ; embracing Mineral and Organic
Chemistry.” By Edward Frankland, F.R.S. &c. Professor of Chemistry at
the Royal Institution of Great Britain and in the Government School of
Mines. London : Van Voorst, 1866.

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Dr. Frankland has gone still further in this direction, and his formulae fully
represent the many links by which the elements of a complex body are united
together. Many of these look very complex, but much of their complexity
disappears when the principle of the system is mastered. Moreover, the
formulae are simpler than the u mixed type ” formulae, besides being
much more perfect expressions of the constitution of bodies.

The new system of nomenclature becoming rapidly adopted by chemists
is also a feature in the volume.

A BOOK ON BONES.*

IT would of course be out of place in these pages to give anything like
an analysis of Mr. Norton’s excellent treatise on the Human Skeleton.
We shall therefore confine ourselves to a short notice of the general character
of the work. Of the importance of an accurate knowledge of the minute
features, connections, and relations, of the bones which form the framework
on which the animal body is built up, there cannot be the faintest doubt.
The difficulties in the acquirement of this knowledge are familiar to all
who have begun the study of anatomy. To the surgeon, as well as to the
physician, an exact acquaintance with the positions and forms of the
several bones, and of their relations to .the soft parts which surround
or are enclosed by them, is absolutely essential. But the study of the
bones is anything but a fascinating pursuit, and the works that have from
time to time been published have not removed the obstacles besetting the
student’s path. In the admirable volumes on our table, the state of things
is different j accuracy and terseness of description, simplicity of exposition,
and an avoidance of all that prolix illustration which some authors have
indulged in, characterise Mr. Norton’s essay. There is, too, a further
advantage which this book possesses over its predecessors, and this advantage
is twofold : the plates are arranged in atlas form, and constitute a separate
volume, and they are executed with a degree of artistic beauty and scientific
truthfulness which cannot fail to elicit the warm admiration of the student,
and the honest recommendation of the professional press.

ESSAYS ON ENGINEERING TOPICS.f

MR. EAIRBAIRN has collected together, as a third series of essays, his
lectures on the Applied Sciences and on other kindred subjects, and his
treatises on the comparative merits of the Paris and London International

*. u Osteology ; a Concise Description of the Human Skeleton, adapted for
the Use of Students in Medicine.” By Arthur Trehern Norton, Assistant
Lecturer and Demonstrator of Anatomy, St. Mary’s Medical School.
London : Hardwicke, 1866.

t “ Useful Information for Engineers.” Third series. By William
Fairbaim, Esq. C.E. LL.D. F.R.S. &c. London : Longmans, Green, and
Co. 1866.

REVIEWS.

75

Exhibitions, on Roofs, on the Atlantic Cable, and on the effect of Impact
on Girders. The work will no doubt be found acceptable reading enough to
some of our readers, most of whom are probably familiar with the style of
the well-known engineer. The several matters discussed hardly admit of
any useful reviewing, so we shall content ourselves with a brief statement
of what they are, in order that the reader may form some idea of the in-
terest of the series to himself.

The lectures are u almost exclusively intended for the moral and intel-
lectual improvement of the engineer and artisan.” There is a lecture on
the Applied Sciences, and another on the Present State of Progress in
Science and Art. The former is almost entirely about steam-engines and
the manufacture of cotton ; the latter has a broader grasp, and in places is
of some interest. There is next a lecture on Labour, its Influences and
Achievements, and after that one upon Literary and Scientific Institutions,
the nature of both of which can be sufficiently divined from their titles.
Another lecture is a sort of Humboldt’s Cosmos in twenty pages. It in-
cludes an account of the experiments of the author conjointly with Mr.
Hopkins and Dr. Joule, and has since received from the author the some-
what odd title of On First Principles and the Thichness of the Earth's Crust
experimentally considered. One other lecture is on Iron and its Appliances,
and treats of the use of iron in the construction of steam-boilers and of
machinery and ordnance. The essays on the Atlantic Cable, on Roofs, and
on the machinery of the International Exhibitions, are of general interest.

THE MANAGEMENT OF STEEL*

THE present edition of Mr. Ede’s little book is so much enlarged as to be
almost a new work. We have scanned its pages with much interest.
It could hardly have been supposed that such a readable book could be
written on such a subject. Few would find it fail to wile away a spare
hour or two. Expanding the title a little, the matters discussed in the
volume are the manufacture of iron and steel, the choosing of steel for
tools, forging iron and steel, annealing cast-iron and steel, hardening and
tempering of cast-iron and steel, expansion and contraction of steel, shrink-
ing of iron and steel, the case-hardening of wrought-iron, and the toughen-
ing of mild cast-steel for guns, shot, railway bars. The whole is written
in homely language, which runs pleasantly enough, notwithstanding the
not unfrequent deviations from grammatical requirements. The work is so
comprehensive in its details that it must prove, we think, extremely useful
to anyone interested in the subject. An extract will probably give a better
idea of it than any further comments from us : — ■

“ The water which is to be used for hardening steel tools, or any other
kind of articles made of steel, should never be quite cold, but should have,

* 11 The Management of Steel.” By George Ede ; employed at the Royal
Gun Factories’ Department, Woolwich Arsenal. Fourth edition, revised
and enlarged. London : William Tweedie, 1866.

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POPULAR SCIENCE REVIEW.

as the term is, the chill taken off ; or, to use other words, the water requires
to he made a few degrees warmer. The reason for this is, that when water
of too cold a temperature is used, it abstracts the heat so suddenly from the
surface of the steel, that it causes a too sudden contraction of the surface
steel, and the expansion of the interior steel in its red-hot state is more than
the hardened crust can bear ; consequently it frequently causes the steel to
break.

u It is quite probable that the interior steel for the moment becomes both
heated and expanded in a higher degree by the sudden compression, for the
sudden contraction of the surface steel by the sudden loss of heat must act
on the interior steel something similar to a blow from a heavy hammer on
the pressure of a squeezer ; and if the steel should happen to be a little too
hot at the time of dipping it into pure cold water, there is as much danger
of its breaking as there is of a glass bottle breaking when boiling water is
poured into it : heat and cold act on glass and other brittle substances in a
similar manner that they act on steel. When boiling water is poured into
a glass bottle, the expansion of the inside glass is so sudden that it is more
than the outside can bear ; consequently the bottle breaks. If glass is heated
to a red heat and plunged into cold water, it breaks into a quantity of small
pieces from the sudden contraction ; if a stone is thrown into the fire, it
breaks from the sudden expansion of its surface.”

BRITISH SPONGES.*

IN one of our last numbers we noticed the first volume of Dr. Bowerbank’s
Monograph, and we spoke of it as a work which every naturalist in-
terested in the study of the Protozoa ought to become acquainted with.
But there were other features in the first volume which gave it a special
importance over the part now issued : it dealt very fully with the general
anatomy and physiology of the Amorphozoa. In volume ii. we find merely
a continuation of the description of genera and species ; this, which was
begun in the first part, though of little interest to the physiologist or the
general zoologist, is to those who are engaged in the pursuit and identifica-
tion of species simply indispensable. The descriptions complete the account
of the British Sponges, and are more comprehensive and detailed than those
of any other systematic treatise we are familiar with. The author, in the
first instance, gives a classified list of all the species described in the volume,
ranging them, according to their affinities, in orders and suborders. In
giving an account of the species, he first supplies the characters in true
technical fashion ; as, for example, in the case of Grantia compressa, he begins
thus, u Compressed, foliaform, slightly pedicelled, surface even, armed with
flecto-claval spicula.” Then he pursues the happier and — for the general
reader — more satisfactory method of giving a long general description of
the sponge, in which all the striking points in its external anatomy are
given in familiar language. The present volume contains no plates, but
the 'descriptions are lucid and comprehensive. In the first volume, Dr.
Bowerbank gave a tabular view of the systematic arrangement of sponges,

* u A Monograph of the British Spongiidse.” By J. S. Bowerbank,
LL.D. F.R.S. &c. Vol. H. London : Published for the Ray Society by
Robert Hardwicke, 1866.

EEYIEWS.

77

and in this he included the exotic as well as the native genera. His reason
for combining the two in the one classification was a belief that some of
the species of exotic sponges would before long be found among our British
sponges. Strange to say, this idea of the author’s has since been realised $
for he has himself, since the publication of his first volume, added two
species of Ecionemici and one of Opli iltasp on gia, an entirely new genus, to our
list of British species. Dr. Bowerbank offers some useful remarks on the
identification of sponges ; generally speaking, he says there is no great
difficulty in the determination of the genus, u but in some cases more than
ordinary caution is necessary in the examination of the specimen under
consideration.” He especially cautions the student against the examination of
sponges by the naked eye alone, for it happens that in many cases the author
has been unable to make a first identification until he had submitted the
structure to minute microscopical examination. Dr. Bowerbank’s second
volume completes his first one, and the two parts form a work which is
creditable to its author and to the useful society which has published it.

WELLS ON DEW.*

FEW of our readers can have failed to have seen reference to Wells’
Essay on Dew, so much eulogised as a splendid example of experimental
research and philosophical induction. Mr. Casella has done good service to
the scientific public in putting again within their reach copies of this esteemed
work. Wells’ theory of the natural formation of dew, and since his time
the one universally received, is that it results from a reduction of temperature
taking place in the bodies upon which the dew forms, by which they become
colder, to a sufficient extent, than the atmosphere around them. Previous to
the publication of this theory, the coldness of bodies on which dew was formed
was held to be an effect of the dew instead of its cause. The reduction of
temperature which causes the dew is the consequence of the radiation of heat
from bodies. Dew is formed at (and not let fall upon) the surface of bodies,
from the aqueous vapours in the atmosphere u in a pellucid state.” This
occurs when the air is cooled, by contact with the cold bodies, to that point
at which the moisture in the air is sufficient to charge it to repletion.

This theory explains, among other observed facts, why different quantities
of dew are formed upon bodies of the same kind in different situations ; why
dew forms on clear nights, and not on cloudy nights ; why the same degree
of cold in a body may be attended with the formation of much, little, or no
dew ,* why dew forms on some substances more than on others ; why dew
and frost (frozen dew) deposits on the projecting parts of bodies more
than on the massive parts ; and, indeed, why all the varied phenomena of
the formation of dew and frost occur as they do.

* “ An Essay on Dew, and several Appearances connected with it.” By
William Charles Wells. Edited, with Annotations, by L. P. Casella,
F.R.A.S. ; and an Appendix by It. Strachan, F.M.S. London : Longmans.
1866.

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POrULAFt SCIENCE REVIEW.

Mr. Casella's notes are very appropriate, and serve, with the matter in the
Appendix, to bring the essay fully down to the present state of knowledge
on the subject. This Appendix, by Mr. Strachan, is formed of articles on the
Action of Aqueous Vapour on Radiant Heat, on Solar Radiation, on Ter-
restrial Radiation, and on the Spectrum of Aqueous Vapour. The publishers
have also issued the work in a handsome form, so that everything about it
leads us to anticipate for it a rapid sale.

MAUNDER’S TREASURY OF SCIENCE.*

THE present edition of Maunder’s Scientific Treasury has been thoroughly
revised, and in great part rewritten, and has upwards of a thousand
new articles added. As a Literary Treasury it has not much to recommend
it, the literary articles being very few and far between. As a Scientific
Treasury it is exceedingly good, and the editor, Mr. Yates Johnson, has, with
considerable success, carried out his attempt to impart to the work an exact
and scientific character, without diminishing its utility as a dictionary for
popular reference.

CONIC SECTIONS.!

THIS is a small treatise extending over only eighty or ninety pages, in-
tended by the author as a first course of lessons and exercises, to prepare
the young student for reading the treatises of Salmon, Hymes, Ruckle, and
Todhunter. Treating only of the equations of the straight line, circle, and
the other conic sections referred to rectangular co-ordinates, and of ele-
mentary problems upon their curves, it is certainly simpler for acquisition
than are the works which discuss the subject more comprehensively. It
puts off, in fact, many of the difficulties of the subject for mastery by the
student at a future day by means of other instruction. All that it contains
appears to be plainly stated, and ought to be intelligible to students of
ordinary capacity, though we are not satisfied that it possesses in this respect
any marked advantage over the treatises of Puckle and Young. It has full
claim to its title of u An Easy Introduction to Conic Sections.”

* u The Scientific and Literary Treasury.” Ry Samuel Maunder. New
Edition, by James Yates Johnson, Cor. M. Z.S. London: Longmans & Co.
1866.

t u An Easy Introduction to the Higher Treatises on the Conic Sections.”
By the Rev. John Hunter, M.A. London : Longmans, 1868.

79

SCIENTIFIC SUMMARY.

AGRICULTURE.

rUIIE Accumulation of the Nitrogen of Manures in Soils. — A paper on this ex-
A tremely important subject has been prepared by Messrs. Lawes and
Gilbert, in wbicb the authors have described the various conditions favourable
and unfavourable to the retention of nitrogen by the soil. The more striking
general result of these researches was that, although a considerable amount of
the nitrogen of the supplied manure which had not been recovered as increase
of crop was shown to remain in the soil, still a larger amount was as yet
unaccounted for. Initiative results indicated that some existed as nitric
acid in the soil, but it was believed that the amount so existing would prove
to be but small. In fact, it was concluded that a considerably larger portion
would remain entirely unaccounted for in the soil than was there traceable,
and the probability was that at any rate much of this had passed off into the
drains, or into the lower strata of the soil. Finally, it was shown, by refer-
ence to field results, that there was not more than one or two bushels of
increase in the wheat crop per acre per annum due to the large accumulated
residue of nitrogen in the soil, notwithstanding its amount was many times
greater than that which would yield an increase of twenty bushels or more
if applied afresh to soil otherwise in the same condition. On the other hand,
it was shown that the effect of an accumulated residue of certain mineral
constituents was not only very considerable in degree but very lasting.

Effects of Irrigation with Development of Certain Plants. — In a series of
papers in the Artisan on the effects of irrigation on plants, the following
statements are made, and deserve attention. It is said that a marked effect of
liberal sewage irrigation on the mixed herbage of grass land is greatly to de-
velop the grasses, to diminish the Leguminosse, and to reduce the prevalence
of miscellaneous or weedy plants, but much to encourage individual species.
Among the grasses, according to locality or other circumstances, the rough
meadow-grass ( Poa trivialis ), couch-grass ( Triticum repens), rough cock’s
foot ( Dactylus glomerata), woolly soft grass (Ilolcus lanatus), and perennial
rye-grass ( Lolium perenne ) have been observed to become very prominent ;
two or three only remaining in any considerable proportion after some years
of liberal sewage application. But sewaged produce being generally cut or
grazed comparatively young, the tendency which the great luxuriance of a
few very free-growing grasses has to give a coarse and stemmy later growth
is not an objection, as in the case of meadows left for hay. — Vide The Ar-
tisan, October, November, December, 186G.

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POPULAR SCIENCE REVIEW.

ASTRONOMY.

At last we have seen a real star-shower ! The scene described with such
force by Humboldt in his Personal Narrative has been made intelligible to
us, although at the same time it is clear that the recent display was, after all,
only a mere indication of the brilliancy of those of 1799 and 1833. Still we
have seen enough to validate the theory of Olmsted, to endorse the admirable
investigation of Newton, and to disconnect for ever meteors from Meteorology.
From this point of view it is extremely satisfactory to learn that the Royal
Astronomical Society have taken steps to obtain a complete discussion of the
observations as soon as possible. The world has been so meteor-mad lately
that it will hardly brook the delay that must take place before the Luminous
Meteor Committee of the British Association make their report at the next
meeting at Dundee.

The December meeting of the Royal Astronomical Society was taken up
entirely with what we may look upon as a preliminary investigation. Two
very important facts 'came out. The first was that the spectroscopic obser-
vations were without result ; the second, that Professor Adams, from his own
observations this year, has arrived at almost the same conclusions as Newton,
whose data were derived from the records of previous showers, commencing
a.d. 902, the account in that year running as follows : — 11 In the year 599
(a.h.) on the last day of Muharram, stars shot hither and thither, and flew one
against another, like a swarm of locusts ; this phenomenon lasted until day-
break ; people were thrown into consternation, and made importunate sup-
plications to God the Most High ; there was never the like seen except on
the coming out of the Messenger of God — on whom be benediction and
peace.”

Let us briefly, in the first instance, state the theory. It is now known that
the bodies, which, when they enter our atmosphere, give rise to the appear-
ances of falling stars and meteors, are so numerous that there are 13,000 of
them in each part of space as large as our earth ; and that, could all which
enter our atmosphere in a period of twenty-four hours — including those
visible in a powerful telescope— be counted, they would number not less than
400,000,000. There is ground for supposing, however, that in the main these
little bodies are congregated into rings, each particle of the ring revolving
like a planet round the sun.

The November ring is so situated in space that it cuts our orbit at the
point occupied by our planet on November 14. This is the descending node
of the ring. Where the other node lies, we do not exactly know ; we only
know that it does not cut our orbit ; if it did, another star-shower would
occur in May. We have, however, possibly another kind of proof of the ex-
istence of the node, not far within our orbit, in the almost^constant retro-
gression of the temperature about May 12, which has been ascribed to the
bodies composing the ring cutting oft' the sun’s heat from'us.

Similarly, one of the nodes of the August ring is situated in the point of
the earth’s orbit occupied by our planet on August 10. The November ring,
according to Newton, is inclined to the plane of the ecliptic, at an angle
of 17° or 19° ; the August one at an angle of 79° or so.

Now, the fact that the early records state the shower to have occurred in

SCIENTIFIC SUMMARY.

81

October places tbe cosmical nature of tbe ring beyond all doubt. It proves,,
in fact, that the meteors are independent of the precession of the equinoxes.

As this ring crosses our orbit in a certain definite point in space, our
earth will always traverse it when it occupies the same definite point of
its orbit with regard to the stars. Our ordinary year, however — the tropical
year — being affected by the precession of the equinoxes (as it is measured
from equinox to equinox), we do not measure it by the stars, but by an
empirical point called the first point of the sign Aries, which is actually at
the present moment in the constellation Pisces. If we refer the recorded
star-showers to the sidereal year, we find an almost absolute identity in the
dates of their appearance.

The ring is not of uniform density throughout, but in one part of it
there is a clustering together of the little bodies of which it is com-
posed— a few stragglers being scattered along the rest of its circuit. Ac-
cording to Newton, the meteors, which revolve round the sun in a direction
opposed to the earth’s motion, complete their circuit most probably in
354*621 days — our own being accomplished in 365*256 days. This is the
same as saying that the annual motion of the group is 1 + -33V5 revolutions y
consequently, the densest portion of the ring is brought into contact with the
earth once in every 133 years, but the earth passes very near this portion
four times in this interval.

Now, given our earth in its orbit cutting such a ring as we have described,,
what must happen ? It will be necessary to enquire into this somewhat
closely to understand the modification which possibly may result from this
year’s observations.

In the first place, the longitude of the spot from which the meteors ap-
pear to proceed will be 90° behind the sun, as that is the spot towards
which the earth is progressing in longitude at any moment, supposing the
orbit circular. Secondly, as the place of a star is subject to variations, owing
to the motion of the earth in its orbit, and the progressive motion of light,
so does the latitude of the radiant from which the meteoric bodies appear
to proceed depend upon their velocity, compared to that of the earth. Thus
Newton, assuming that the velocity of the meteors was equal to that of
the earth, but in a contrary direction, argued an inclination of 17° from a
radiant point, with a latitude of 8° 30'. Professor Adams, we believe,,
already sees reason to doubt the exactness of the period determined by
Newton, and the latitude of the radiant this year appears to have been
somewhat greater than that determined from the prior observations. But,
as Professor Adams has shown, the fact that the longitude agrees with
what Mr. Pritchard has aptly termed the apex of the earth's way is beyond
all question, when we take the elliptic form of our orbit into consideration,
as the difference between them lies within the errors of observation, and,
moreover, a correction must also be applied for the position of the observer
with regard to the position of the earth’s centre and the direction of its
motion.

There seems a little doubt as to whether there was not more than one
radiant point in the last display. The principal one is Leo — the exact
point in longitude towards which the earth was journeying at the time
was very marked.

82

POPULAR SCIENCE REVIEW.

Among all the meteors seen by the present writer, from 11 p.m. on Tues-
day till 2 a.m. on Wednesday morning, two only were decided exceptions to
the general direction. At the radiant point itself, it was a subject of gene-
ral remark, the meteors appeared trainless, and shone out for a moment
like so many stars, because they were directly approaching us ; near this
spot they were so numerous, and all so foreshortened, and for the most
part faint, that the sky at times put on almost a phosphorescent appear-
ance. As the eye travelled from this region, the trains became longer, those
being longest as a rule which first made their appearance overhead, or
which tended westward. There were moments in which the meteors belted
the sky like the meridians on a terrestrial globe, the pole of the globe being
represented by the radiant point.

It is to be hoped, now the full significance of the radiant has come out,
that we may soon have a complete discussion of all the radiant points
hitherto determined, and their relationship with the direction of the earth’s
motion.

So much for one part of the theory. The Astronomer Eoyal has called
attention to the meaning of the lulls in the display ; we have here possibly
a means of determining the shape of the meteoric ring through which we
passed. It will be seen from the following table that these lulls were but
subsidiary to a well-marked rise and fall : —

li. h.

No. of Meteors.

Tuesday night, between 9 and 10

10

Nov. 13.

9 — 11

15

11 — 12

. 168

Wednesday morning,

12—1

. 2032

Nov. 14.

1—2

. 4860

2—3

. 832

3—4

. 528

4—5

40

From 9 to 10.30 the rate of fall was one per minute ; at 12 the numbers
increased, and rose at 12.10 to 20 a minute ; twenty minutes afterwards the
number was 37; then after thirty minutes, 70; then 47 a minute for the
next ten minutes ; and then a rise to 90 a minute. The total number re-
corded was 8,485, and the time of maximum was between 1 and 2.

That the ring is thin seems to follow from the fact that the maximum
display was seen at Malta pretty much at the same time as writh us, and
that the shower had entirely ceased by the time the radiant point had risen
in America.

It is not necessary on the present occasion to refer more particularly to the
various observations made ; we trust soon to be in a position to give a
summary of all the facts new to science gained from them.

We now come to the Sun. Messrs. De La Rue, Stewart, & Loewy have
published the Second Series of their u Researches on Solar Physics;” giving
the area-measurements of the sun-spots observed by Carrington during the
seven years from 1854-1860 inclusive, and deductions therefrom.

SCIENTIFIC SUMMARY.

83

The authors began by establishing the trustworthiness of Carrington’s
sun-pictures, and then measured for each group the amount of spotted area,
inasmuch as the method hitherto employed, namely, the mere statement of
the number of sun-spots occurring at any period, can only be supposed to
afford very approximate means of estimating the extent of solar activity at
that period ; while, again, if we wish to study the behaviour with respect to
size of each group as it passes over the visible disk, this can only be done
accurately by the laborious but sure method of measurement.

One of the enquiries has reference to the relative distribution of spotted
area over different parts of the solar disk. The word disk is used in contra-
distinction to surface , because it is evident that, on account of the sun’s
rotation, the centre of his visible disk on one day does not represent the
same portion of the solar surface as on another day ; indeed from this cause
it is well known that sun-spots travel over the visible disk from left to right.
It is therefore one enquiry to study from day to day the relative distribution
of spotted area over different parts of the sun’s actual surface, and another
to study the same from day to day over different parts of his apparent
disk.

It follows from the investigations— for details of which we must refer to
the paper itself — that, in the first place, during the time embraced in a series,
the amount of spotted area which crosses one ecliptical longitude is different
from that which crosses another — that is to say, the average size of a spot
varies with the ecliptical longitude.

In the second place , there seems to be a periodical recurrence of the same
sort of behaviour, the period of recurrence of the same behaviour appear-
ing to be nineteen or twenty months.

In the third place, in all these recurrences the progress of the maximum
is from left to right, not right to left. The authors continue : —

O y C

“We cannot see that these phenomena can possibly be explained unless
it be admitted that the behaviour of sun-spots is subject to some external
influence, the nature of which will best be determined by the order of
recurrence and length of period of the phenomena in question.

11 In the first place, it is clear that the influence is not stationary, other-
wise its period would be one year, that being the time in which the earth
(which must be regarded as the standpoint from which these phenomena
are viewed) accomplishes one revolution round the sun. Again, since the
march of the phenomena is from the left to the right of the earth, this would
seem to identify the influence with one of the inferior planets which passes
over the sun’s disk in this direction, the superior planets going the opposite
way.

“ The period of twenty months will now enable us to determine which of
the inferior planets exercises the predominant influence on sun-spots. We
have to ask which of the two inferior planets takes twenty months to return
to the same position with respect to the earth. This evidently points to
Venus, for which the synodical period is 583 days, or between nineteen and
twenty months. We may remark that, apart from all observation, if we
suppose the various planets to affect the behaviour of sun-spots, the influence
of Venus should be very great, on account of its nearness to the sun com-
bined with its very considerable size The average size of a spot

YOL. YI. — NO. XXII.

II

84

POPULAR SCIENCE REVIEW.

would appear to attain its maximum on that side of the sun which is turned
away from Venus, and to have its minimum in the neighbourhood of this
planet.”

In reply to the question, Does not Jupiter appear to exert any influence ?
as, although its distance is much greater than that of Venus, yet its mass is
very great, it is shown that the influence of Jupiter is really great, although
not apparently predominating.

Not only have we these effects in longitude, hut it would appear that
spots are nearest to the solar equator when the heliographical latitude of
Venus is 0°, and are most distant from the solar equator when this planet
attains its greatest heliographical latitude.

The concluding remarks of the authors are as follows : —

“ The following question may occur to our readers, How is it possible that
a planet so far from the sun as Venus or Jupiter can cause mechanical
changes so vast as those which sun-spots exhibit P We would reply in the
following terms to this objection :

“We do not, of course, imagine that we have as yet determined the
nature of the influence exerted by these planets on the sun ; but we would,
nevertheless, refer to an opinion expressed by Professor Tait, ‘that the pro-
perties of a body, especially those with respect to heat and light, may be
influenced by the neighbourhood of a large body.’ Now, an influence of
this kind would naturally be most powerful upon a body such as the sun,
which possesses a very high temperature, just as a poker thrust into a hot
furnace will create a greater disturbance of the heat than if thrust into a
chamber very little hotter than itself. In the next place, it is not to be
inferred that the mechanical equivalent of the energy exhibited in sun-spots
is derived from the influencing planet any more than it is to be inferred that
the energy of a cannon-ball is derived from the force with which the trigger
is pulled.*

“ The molecular state of the sun, just as that of the cannon or of fulmi-
nating powder, may be extremely sensitive to impressions from without ;
indeed we have independent grounds for supposing that such is the case.
We may infer from certain experiments, especially those of Cagniard de
Latour, that at a very high temperature and under a very great pressure
the latent heat of vaporisation is very small, so that a comparatively small
increment of heat will cause a considerable mass of liquid to assume the
gaseous form, and vice versa. W e may thus very well suppose that an
extremely small withdrawal of heat from the sun might cause a copious
condensation ; and this change of molecular state would, of course, by means
of altered reflection, &c., alter to a "considerable extent the distribution over
the various particles of the sun’s surface of an enormous quantity of heat,
and great mechanical changes might very easily result.

“ Again, although we cannot suppose our earth to be nearly so sensitive
as the sun, yet the question may be entertained, Does the moon exert an
influence of this kind upon the earth ?”

It is not a little curious that since the authors’ preliminary research into

* It is, however, a possible enquiry whether these phenomena do net imply
a certain loss of motion in the influencing planets.

SCIENTIFIC SUMMARY.

85

the behaviour of sun-spots, a suggestion of the illustrious Galileo, which he
appears not to have published from want of evidence, has been brought to
light by the Rev. William Selwyn. This suggestion advocates a method of
research allied to that in which the Kew astronomers are now engaged.

Spectroscopic Observations of the Sun is the title of a paper recently
presented to the Royal Society by Mr. J. Norman Lockyer. The author re-
marks that the two most recent theories dealing with the physical con-
stitution of the sun are due to M. Faye and to Messrs. De la Rue, Balfour
Stewart, and Loewy. The chief point of difference in these two theories
is the explanation given by each of the phenomena of sun-spots. Thus,
according to M. Faye, the interior of the sun is a nebulous gaseous mass
of feeble radiating-power, at a temperature of dissociation ; the photo-
sphere is, on the other hand, of a high radiating-power, and at a temperature
sufficiently low to permit of chemical action. In a sun-spot we see the
interior nebulous mass through an opening in the photosphere, caused by an
upward current, and the sun-spot is black, by reason of the feeble radiating-
power of the nebulous mass. In the theory held by Messrs. De la Rue,
Stewart, and Loewy, the appearances connected with sun-spots are referred
to the effects, cooling and absorptive, of an inrush, or descending current, of
the sun’s atmosphere, who is known to be colder than the photosphere.

In June 1865 the author communicated to the Royal Astronomical Society
some observations which had led him independently to the latter conclu-
sion. The observations indicated that, instead of a spot being caused by
an upward current, it is caused by a downward one, and that the results,
or, at all events, the concomitants, of the downward current are a dimming
and possible vaporisation of the cloud-masses carried down.

On March 4 of the present year a spectroscopic observation of sun-spots
was commenced, with a view of endeavouring to test the two rival theories,
and especially of following up the observations before alluded to.

On turning the telescope and spectrum-apparatus, driven by clockwork,
on to the sun at the date mentioned, the solar spectrum was observed in the
field of view of the spectroscope with its central portion (corresponding to
the diameter of the umbra falling on the slit) greatly enfeebled in brilliancy.
All the absorption-bands, however, visible in the spectrum of the photo-
sphere, above and below, were visible in the spectrum of the spot ; they,
moreover, appeared thicker where they crossed the spot-spectrum.

Mr. Lockyer was unable to detect the slightest indication of any bright
bands.

Should these observations be confirmed by observations of a larger spot
free from lt cloudy stratum,” it will follow, not only that the phenomena
presented by a sun-spot are not due to radiation from such a source as that
imagined by M. Faye, but that we have in this absorption-hypothesis a
complete or partial solution of the problem which has withstood so many
attacks.

The paper concludes as follows : u Seeing that spectrum-analysis has
already been applied to the stars with such success, it is not too much to
think that an attentive and detailed spectroscopic examination of the sun’s
surface may bring us much knowledge bearing on the physical constitution
of that luminary. For instance, if the theory of absorption be true, we may

h 2

86

POPULAR SCIENCE REVIEW.

suppose that in a deep spot rays might be absorbed which would escape
absorption in the higher strata of the atmosphere ; hence also the darkness
of a line may depend somewhat on the depth of the absorbing atmosphere.
Ma}r not also some of the variable lines visible in the solar spectrum be due
to absorption in the region of spots P and may not the spectroscope afford us
evidence of the existence of the i red flames ’ which total eclipses have re-
vealed to us in the sun’s atmosphere j although they escape all other methods
of observation at other times P and if so, may we not learn something from
this of the recent outburst of the star in Corona ? ”

The Moon Committee have issued a circular pointing out an observation
recently made by Dr. Schmidt, of Athens, which may prove to be of the
utmost importance. The crater Linneus, in the Mare Serenitatis, has
altogether lost its crateriform appearance, and appears to be obscured by
something brighter than the surrounding parts of the lunar surface. Can it
be that there is an eruption going on, and that we have here a cloud of smoke,
which, in our almost atmosphereless moon, fills up the cavity of this crater
like a liquid, bereft as it must be of all power of ascension ? On December
15, it certainly appeared very different from all the other craters in the loca-
lity, which in Beer and Madler’s map are made to put on the same appear-
ance. Schroter observed a similar phenomenon in Linneus , in 1788.

The planet Mars is now coming round again, and although it is not a very
favourable opposition, the declination of the planet is so high that we may
fairly hope for some good observations. Mr. Bishop has issued a circular
(which can be had upon application to his observatory, at Twickenham),
giving the position of the planet’s axis, the planet’s diameter, and the illu-
minated portion of the disk, from the present time to March 28. This is the
sixth circular for which astronomers are indebted to the labour of Mr. Hind
and the liberality of Mr. Bishop.

The asteroids now number 91. @ was discovered by Stephan in August,

(90) Antiope by Luther in October.

Sir John Herschel, we are informed, has communicated to the Royal
Astronomical Society, a catalogue of all the double stars observed by Sir
"William and himself. The places are reduced to 1880. The Rev. W. R.
Dawes has also done the same with the stars he has observed. The two cata-
logues will form a precious boon to astronomers.

The monthly notices for November contain a paper by Mr. Lynn, on a new
mass of Jupiter, from which we gather that the observations of Themis require
an augmentation of Bessel’s mass of Jupiter, amounting to the joffoo Par^
its value. This gives, for the actual mass of Jupiter, compared with the
sun, the fraction a mean between the old values, as determined by

Airy and Bessel, from the motions of the satellites.

The same number also contains a valuable paper by Mr. Baxendell on
T Coronse, which, since our last summary was written, has risen again from
the- 10th to the 74 magnitude. Mr. Baxendell states that, on May 7, he ob-
served all the naked eye variables, and several telescopic ones, among them
two in Corona, but saw nothing of the new star. There are, however, other
grounds for looking upon a statement made by a certain American named
Barker, that he observed the star on May 4, as dishonest and untrustworthy.
The fact of the suddenness of the break-out seems beyond all doubt.

SCIENTIFIC SUMMARY.

87

The foreign journals have been remarkably destitute of astronomical
news lately. This is fortunate, as our summary already exceeds its ordi-
nary limit.

BOTANY.

The u Cybele HibernicaT — The invaluable work which Mr. Watson achieved
for England is being imitated on the other side of the Irish Channel.
Messrs. Moore and More have issued a volume upon the subject of the dis-
tribution of Irish plants, and the facts it lays before the Botanical public are
both numerous and interesting. Taking the number of species for Britain
proper at Mr. Watson’s estimate of 1,425 species, the authors of the u Cybele
Hibernica ” claim for Ireland about 1,000 species. Of the 532 plants of the
British type, Ireland has all, or very nearly so. The Atlantic type is the only
other one where she has decidedly more than half, forty-one species out
of seventy. Of the Boreal species (Highland, Scottish, and intermediate types
taken together), although there is not a single one of the twelve provinces in
which there is not a hill of upwards of 2,000 feet in altitude, Ireland has
only 106 species out of 238. Of the 458 English and local species she has
just over one-half ; and, finally, out of the 127 Germanic species only 18.

Doubtful species being left out, the number of species ascertained in Ire-
land, but not known in Britain proper, is reduced to twelve. Only five of
these — Saxifraga Geum , Erica mediterranean Arbutus Unedo, Dabcecia poly -
folia , and Neotinea Intacta — are for Europe as a whole specially south-western
in their distribution ; whilst three — Sisyrinchium anceps, Neottia gemmipara ,
Naiasjlexilis, — are North American plants not known on the European con-
tinent.— Vide The Journal of Botany, October.

The Flora of the Fiji Islands . — The fifth part of this fine work by Dr. See-
mann has just been published ; this, we learn, completes the Monopetalous
and Polypetalous orders.

The Cedars of Lebanon. — A very interesting communication relating to the
far-famed (t cedar of Lebanon ” has been recently made to the Gardener's
Chronicle by Dr. J. I). Hooker. Dr. Hooker states that he has been informed
by the Bev. M. Tristram that an American missionary, Mr. Jessup, has dis-
covered several new groves of cedar-trees. Of these there are five, three of
great extent, east of ’Ain Zabalteh, in the Southern Lebanon. This grove
lately contained 10,000 trees, and had been purchased by a barbarous sheikh
from the more barbarous Turkish government for the purpose of trying to
extract pitch from the wood; the experiment failed; the sheikh was
ruined, but the result was the destruction of several thousand trees. One of
the trees measured fifteen feet in diameter, and the forest is full of young trees,
springing up with great vigour. He also found two small groves on the
eastern slope of Lebanon, overlooking the Buka’a, above El Medeuk ; and
two other large groves, containing many thousand trees, one above El Baruk,
and another near Ma’asiv, where the trees are very large and equal to any
others ; all are being destroyed for firewood. Still another grove has been

88

POPULAR SCIENCE REVIEW.

discovered near Duma, in the western slope of Lebanon, near to the one dis-
covered by Mr. Tristram himself.

The Newfoundland Heather . — About a year ago we pointed out in our
Summary that the Calluna vulgaris, or common British heather, had been said
to have been found growing in North America. Some interest attaches
to the subject, and therefore we are glad to direct the attention of our
readers to a paper by Dr. Seemann in the Journal of Botany (No. xlvi.)
upon a comparison between the American and the British species. Dr. See-
mann observes that Dr. Moore, of Dublin, who cultivates the two varieties
side by side, noticed that, u whilst the Newfoundland one always suffered
from frost, and turned brown during the mild Irish winter, the common
British form growing by its side was unaffected by cold, and preserved its
usual green colour. ” Dr. Seemann states that, though at first sight the
plants seem to be as different as possible from each other, there is never-
theless considerable difficulty in indicating the structural differences between
the two. Dr. Seemann gives the following as the chief points of difference
between the British and American specimens. The leaves of the New-
foundland plant are always closely adpressed to the stem ; those of Calluna
vulgaris are generally patent ; the pedicels of the Newfoundland plant are
always naked ; those of the true C. vulgaris are, especially those of the
lowest flowers, foliaceous, so that they form little branchlets, terminating-
in a solitary flower; whilst the sepals and petals of the Newfoundland
plant are ovate and indexed, those of the common British heather are
rather oblong and not indexed. Again, in the Newfoundland plant the
tip of the flowering branches does not put forth fresh shoots whilst the
flowering lasts ; but in the common British heather a fresh shoot issues
when the flowering is at its height.

The History of the Potato. — In a paper lately read by Mr. Crawfurd, on
u The Relation of Plants to Ethnology,” a very short but complete account
was given of the introduction of the potato into Europe. The potato is still
found on the western slopes of the Andes, the tubers, however, being no
bigger than the common filbert. Even the Indians, said Mr. Crawfurd, cul-
tivated the potato before the arrival of the Europeans. It was first brought
from America to Ireland, where it was cultivated in 1586 ; but it is said to
have been introduced into Spain and Portugal even before this date. From
Ireland it found its way to the Low Countries and to Germany, and from
Spain it reached Italy and France. It is an object of cultivation in Asiatic
countries only where Europeans have colonised or settled, and there chiefly
for their consumption, and only since the beginning of the present century.
It is successfully cultivated in Australia and New Zealand, which produced
no esculent farinaceous root at all, not even the yam, the taro, or the
manioc.

Functions of the Stomata of Leaves. — The ordinary theory that the stomata
of leaves are the bre ath i n g- o rgan s through which the carbonic acid is decom-
posed has met with two new opponents in MM. Duchartre and Boussingault.
These observers allege that the quantity of carbonic acid decomposed by the
leaves of plants has no relation to the number or superficial extent of the
stomata. They further state that in the case of fruits the green parts de-
compose carbonic acid, and yet contain no trace of stomata.

SCIENTIFIC SUMMARY.

89

The Starchy Matter of Plants. — A paper, laid quite recently before the
French Academy by M. Arthur Gris, states as a conclusion that the amy-
laceous matter contained in plants is partly resorbed during the development
of the flowers, but that this process is not continued during the develop-
ment of the fruit.

The Fecundation of the Floridece. — There are few subj ects of higher inte-
rest to the student of vegetable physiology than that of the mode of repro-
duction of plants. The processes which occur among the Algse generally
have been of late years very clearly made out ; but it would seem, from a
memoir published by MM. Bornet and Thuret, that the fecundation of
some of the Algae is different from what is generally thought to be the pro-
cess. These authors have written a very long paper, describing the structure
and fimctions of the antherozoids, &c. of the Florideae, and have given a
number of details which we cannot lay before our readers. Their general
conclusion, however, shows the view they take, and is as follows : — u It
appears from the preceding observations that the phenomena of fecundation
in the Florideae are very different from those which occur in the other Algae.
The structure of the organs, their mode of action, the period when their
fimctions are discharged, and the effects which they produce, distinguish
them from the other Algae. There is no direct action of the antherozoids on
the reproductive bodies in these plants. The operation is less simple, and
in some respects resembles that which occurs in the higher plants. Here we
find fecundation produced by motionless corpuscles on an external organ, the
result of which is the complete development of the organ of fructification.”
—Vide Comptes Rendns , Sept. 24.

Chinese Soap Seeds. — M. Payen, in a memoir on the Leguminosae, whose
seeds are used as soap by the Chinese, has supplied botanists with the fol-
lowing interesting facts : These seeds are of two species, which differ slightly
in chemical and microscopical characters. The first series, which has been
more extensively examined than the other, is considered by M. Decaisne to
belong to the genus Dyalhim. In the seed one finds, first, a stratum of about
two or three millimetres thick, composed of cells, containing grains of
starch, a substance analogous to saponine, and a nitrogenous oil. Within
this envelope is the embryo, surrounded by a compact perisperm, whose
structure and composition are quite peculiar. In this M. Payen has found
cells with thin walls, containing grains of starch, coloured yellow by iodine,
and contracted by sulphuric acid, and a special amorphous secretion, which
absorbs thirty times its weight of water. This absorption gives rise to a
sort of jelly, which, when separated, precipitated by alcohol, and evaporated
to dryness, gives colourless tablets, like layers of gelatine. This, says M..
Payen, is not to be confounded with pectine and bodies of the pectine group.
It is allied to cellulose, but is not coloured blue by iodine. M. Payen pro-
poses to term it Dyallose. — Vide L'Institut , No. 1707.

Deceased Botanists. — We. regret to have to record the deaths of two most
distinguished continental botanists, Dr. Kotschy, of Vienna, and Dr. Met-
tenius, of Leipzig. The former was for some time assistant in the Vienna
Herbarium, and was author of several books of travel and of a monograph
on Oaks. Dr. Mettenius was Professor of Botany and director of the Botanic
Garden at Leipzig.

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POPULAR SCIENCE REVIEW.

The Diagnosis of the Alga. — Upon this subject a controversy has been
going on for some time past between Mr. Archer, of the Dublin Natural
History Society, and Dr. Braxton Hicks, F.R.S. The latter contends that
there are so many intermediate forms between the earlier and later stages of
the development of certain plants, which are in every respect like what Mr.
Archer considers adult forms, that diagnosis from the examination of speci-
mens alone not undergoing development is unsatisfactory. Dr. Hicks asks
how Mr. Archer can say whether a specimen is a fixed form, a separate
entity, or merely a transitorial form of some other growth. To this Mr.
Archer replies that the mere fact of conjugation taking place is sufficient to
prove the adult nature of the species under examination. Dr. Hicks, we
believe, doe3 not look on conjugation a3 a true generative act. — Vide
Quarterly Journal of the Microscopical Science , October.

CHEMISTRY.

Action of Magnesium on Neutral Metallic Salts. — In a paper read before
the French Academy, on October 1, M. A. Commaille states that hydrogen
is always evolved when a metal is precipitated by magnesium, and in such
cases the precipitation is incomplete. In the case of sulphate of iron,
hydrated protoxide of iron is thrown down ; in an acid solution, metallic
iron is precipitated. With mixed chromic and chromous chloride, hydrated
sesquioxide of chromium is precipitated. With manganous sulphate, the
reaction is the same as with iron. With cobalt sulphate, the reaction is
very slow ; after a few days the hydrated oxide, Co304, deposits on the
magnesium. With nickel sulphate, the precipitate formed is the hydrated
protoxide. With oxalate of uranium, a golden-coloured deposit of hydrated
sesquioxide is produced — U203,H0. With sulphate of zinc, there is an
energetic action, and the metal, the hydrated oxide, and sub-sulphate are
precipitated. With chloride of cadmium, the reaction is also very energetic,
and a mixture of oxychloride of cadmium, and metallic cadmium, is preci-
pitated. Bismuth salts being acid give a precipitate of pure metallic
bismuth. Protochloride of tin gives spongy tin and stannic acid. The
disengagement of gas is very strong with neutral chloride of lead; the
deposit consists of lead mixed with oxychloride.

Magnesium Rods for Toxicological Purposes. — The Chemical News states
that some of Mr. Mellor’s magnesium rods which have been examined by
the editor have been found to answer their purpose exceedingly well.
They are intended to replace zinc in the detection of arsenic and other
poisonous metals. When examined in connection with Marsh’s apparatus,
they gave no indication of deposit which could be confounded by the
chemist with arsenic, &c.

Preparation of Pare Caustic Alkalies. — A method by which the carbonates
may be rendered so pure that they only exhibit traces of chloride has been
discovered by M. Graeger. This chemist first treats them with carbonate
of silver, and then boils them with lime from calcined marble. The
ley is then filtered through a funnel, in the bottom of which are placed

SCIENTIFIC SUMMARY.

91

fragments of marble and powdered marble, first pouring distilled water
through, till it passes perfectly limpid. — Journal fur praktische Chemie.

Organic Matter in Water. — As it has been proposed to obtain the future
water-supply of London from the English lakes, it is of interest to compare
(as has been done by the Chemical News ) the analysis of the water of the
lakes with that of the London waterworks. According to Mr. Way, the

grains of organic matter per gallon is in —

River Lowther 062

Haweswater 062

Ulleswater ....... 0-35

Thirlmere . . , . , . . 077

giving an average of 0*59 grains.

According to Dr. Letheby, the organic matter per gallon is in the —
Grand Junction Waterworks .... 0-60

West Middlesex 0-48

Southwark and Yauxhall .... 064

Chelsea 0-56

Kent 0*03

New River 0-22

East London . 0-56

showing an average of 044 grains ; or a balance against Cumberland of
015 grains of organic matter per gallon. — Vide Chemical News, November.

A Crystalline Fatty Matter in Urine. — At a recent meeting of the Royal
Society, Mr. Edward Schunck read a paper with the above title. Mr.
Schunck says that the occurrence of fatty matter in urine is a somewhat
rare phenomenon, and is generally considered as a symptom of disease.
In most of the instances that have come under his notice, it was found
associated with albumen in which the fatty particles were embedded ; more
frequently, however, it is found enclosed in cells so heavy as to sink to the
bottom of the vessel. Mr. Schunck gives the following method for the
extraction of the peculiar brown-yellow oil which he described. Healthy
urine is filtered through animal charcoal, till the percolating liquid ceases to
be decolorised, and begins to pass with extreme slowness. It will be
found that a very small quantity of charcoal will decolorise a very large
portion of the liquid. The charcoal is then well washed with water to dis-
solve the soluble salts, dried, and afterwards treated with boiling alcohol, to
which it communicates a bright-yellow colour. The liquid must then be
filtered, evaporated, and the brown syrup residue mixed with water, 'which
deposits a brown semifluid fatty matter, which can be separated by filtra-
tion.

On Blue Litmus Paper as a Test for Acidity. — In the course of a recent
discussion at the French Academy, on the subject of silkworm disease,
M. Chevreul made some interesting observations on the above subject. It
appears that the most delicate blue paper owes its colour to the red prin-
ciple of litmus united with subcarbonate of potash ; and when a body
reddens this, it only signifies that the substance has more affinity for potash
than the red colouring matter of litmus has. But in the preparation of
ordinary blue litmus paper, instead of using paper free from mineral matter,

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POPULAR SCIENCE REVIEW.

the makers use paper containing suhcarbonate of lime, sesquioxide of
iron, &c. Now suhcarbonate of lime also colours litmus blue, and this
compound gives up its base to acids with much greater difficulty than the
blue potash-compound does. Therefore, in order to prepare the most
delicate blue litmus-paper, the latter should be first soaked in hydrochloric
acid, and then well washed, before applying the litmus. Ordinary red
litmus-paper is much more sensitive to alkaline reaction than blue paper
is to acid. M. Chevreul said that the most delicate means to detect
acidity was to put a freshly-cut piece of campeachy-wood into distilled water.
If free from alkali, the. colour will be yellow, but if there is a trace of
alkali present, the tint is purple ; then add a minute quantity of acetic acid
on the point of a quill, when the colour will turn yellow. This liquid
becomes purple with a trace of alkali, and acids change the purple to
yellow.

Analysis of the Waters of Pergeze. By M. A. Bechamp. — We learn from
our contemporary, the Chemical News , that M. Bechamp has discovered in
these waters considerable quantities of acetic and butyric acids. This is
the first time that organic acids have been found in a French spring. Upon
examining the deposit of this water under the microscope, a considerable
number of mobile corpuscles were observed, similar to those seen in native
chalk. M. Bechamp supposes that these are the causes of the formation of
the volatile fatty acids.

The Compounds of Niobium. — M. Marignac, in a recent memoir, endeavours
to disprove the existence of ilmenium. He believes that the niobic acid
extracted from columbite is not a mixture ; that its density is about 4-5 ;
and that the two products, obtained by M. Hermann, having densities of 5
and 8-8, are mixtures of this acid with bodies of a greater and less density,
chiefly tantalic and titanic acids.

Detection of Free Sulphuric Acid in Acetic Acid. — The following simple
process for this purpose is given in Boettger’s Polytechnisches Notizblatt :
Boil about fifty cubic centimetres of the acid to be tested in a retort with a
very small quantity of starch, until half the liquid is distilled ; after it has
cooled, add a drop of tincture of iodine. If, under these circumstances, a
blue coloration be produced, no sulphuric acid is present. If the blue colour
does not appear, it may be concluded that sulphuric acid is present, which,
by reacting on the starch, will have transformed it to glucose. With tinc-
ture of iodine, glucose gives no particular coloration. Sulphuric acid, thus
detected, may be estimated by the ordinary processes.

A Neio Form of Gunpowder. — This peculiar compound, the invention of
Herr G. A. Neumeyer, is said to possess the following properties : —

1. The powder bums, but does not explode, if the air has access.

2. Neither pressure nor percussion will cause it to ignite.

3. Its explosive force is equal to that of ordinary powder or even greater.

4. - It leaves behind less residue than ordinary powder.

5. It does not attract more moisture from the atmosphere than ordinary
powder.

6. It leaves behind less powder-smoke than ordinary powder. Its smoke,
moreover, is light, disappears quickly, and has no injurious effect on the
health of the workmen.

SCIENTIFIC SUMMARY.

93

7. It is cheaper than ordinary powder in the proportion of 30 to 31. The
prices by weight are the same, but as it has been found that 76^ grains of
Neumeyer’s have the same explosive force as 79^ grains of ordinary powder,
the above proportion may easily be deduced. — Vide Berg- und hiittenman-
nische Zeitung , No. 36, 1866.

The Synthesis of Besor cine. — Herr Korner has been engaged in some re-
searches upon resorcine. To those who have -waged war against chemical
technicalities, the following paragraph may be of interest. Ilerr Korner
starts with benzol ; converts this into binitrobenzol ; from this prepares
paranitroaniline ; transforms the nitrate of this base into nitrate and then
sulphate of paradiazonitrobenzol. Under the influence of hydriodic acid this
salt gives paraiodonitrobenzol, which, with tin and hydrochloric acid, is
reduced to paraiodaniline. From the nitrate of this base the sulphate of
paradiazoiodobenzol is formed. This salt decomposed by boiling water gives
a new acid, paraiodophenic acid. This is solid and well crystallised ; its
most remarkable property is to give, under the influence of fused potash, a
crystallised combination which is the inferior homologue of orcine described
by MM. Hlasiwitz and Barth under the name of resorcine. Herr Korner hopes
to show that phloroglucine and pyrogallic acids are trihydroxylic derivatives
of benzol, and that, by starting from toluol, he will effect the synthesis of
orcine.

The Detection of Iodine. — Mr. Carey Lea, the celebrated American photo-
grapher, has suggested a new and useful test for the presence of iodine. It
states that, while engaged in testing for iodine, it occurred to Mr. Lea that
the facility with which that body is eliminated from its hydrogen and me-
tallic combinations by chromic acid would make the latter substance a
valuable means of bringing about the starch reaction, and a few experi-
ments completely confirmed this view. If, for example, an extremely dilute
solution of iodide of potassium, such that the addition of nitric acid and
starch produces no perceptible effect, is taken, the further addition of a
single drop of very dilute solution of bichromate of potash will instantly
bring about the characteristic reaction. When chlorhvdric acid is substi-
tuted for nitric, the effect of the bichromate is (as was to be expected) still
more marked. The test has the full delicacy at least of the chlorine test,
with this great advantage that an excess of the reagent does not prevent
the reaction.

Wine and Wine Sic7mess. — The results of M. Pasteur’s valuable researches
on this subject may thus be summarised : — 1. That the dangerous changes
which occur in wine arise from causes which are mixed up with those to
which fermentation is attributed. 2. That the heating of ordinary wine to
the extent of 50° centrigrade is sufficient to kill all microscopic vegetation,
or the ferments which produce them : fermentation and all other dangers
due to these causes being thus arrested or prevented. 3. The application
of the amount of heat indicated does not in any way effect the flavour or
the colour of wine, and assures brightness. 4. Wines which have been sub-
mitted to such temperature appear capable of being kept indefinitely in
closed vessels. 5. When exposed to the air, such wines, it is true, may
become affected after a certain lapse of time ; but this is in consequence of
the air supplying them with the living germs of those ferments which they
previously lost by the action of heat.

94

POPULAR SCIENCE REVIEW.

How to Silver Glass. — Those who are familiar with Baron Liehig’s inves-
tigations on the subject of glass silvering are aware of the numerous diffi-
culties that attend the deposition of mercury amalgam upon glass ; the follow-
ing method which has been suggested by Herr Bernhardt will interest our
chemical readers. Prepare four solutions — first, 10 grammes of nitrate of
silver to 100 grammes of water ; second, an aqueous solution of ammonia of
0-984 density; third, 20 grammes of caustic soda and 500 grammes of
water ; and fourth, a solution of 25 grammes of sugar in 200 grammes of
water, to which is added a cubic centimetre of nitiic acid, at 36°, and let the
whole boil for twenty minutes. When cold, add 50 cubic centimetres of
alcohol, and as much water as will make up the total quantity to 500 cubic
centimetres ; then take 12 parts of the first, 8 parts of the second, and 20
parts of the third solution, add 60 parts of water, and let the mixture
stand for twenty-four hours ; lastly, the solution No. 4 is added when the
whole becomes of a blackish tint, in consequence of the finely divided pre-
cipitate of silver which begins to fall. M. Bernhardt has discovered that
the deposition of the silver is greatly aided by motion, and that, when the
bath is continually shaken, the deposit on the inner surface of glass vases is
always satisfactory, and he recommends that in silvering plates of glass they
shall be placed in evaporating dishes, or other vessels, so that the sides may
give an oscillating motion to the liquid in the bath when shaken. In acting-
on large articles, he recommends the glass plates, or other objects, to be
fixed within tubs or vats, which may then be rolled or rotated pretty
rapidly. — Journal of Society of Arts, November 1866.

Observation on the Passage of the Spark of an Induction - Coil through Flame.
By A. Kundt.— If the current of sparks of an induction-coil be passed
through the luminous flame of gas or of a candle, no alteration is seen in
the flame, excepting that in the path of the sparks the flame is intensely
luminous, and under certain circumstances this brightly luminous path
of sparks is traversed by dark cross bands. When the polar wires are suitably
introduced, it appears constant and steady. Yet, if the flame is viewed in
a slowly rotating mirror, or in one which is moved to and fro in the hand,
this apparent constancy is found really not to exist ; for, looked at in the
mirror, the image does not seem constantly broadened, but the part above
the spark appears alternating, like the flame of a chemical harmonicon when
looked at in a rotating mirror. From the upper point of the flame to the
spark, the image in the mirror appears to have serrate incisions, and at the
lower point of each dark incision there is a passing spark. During this
transition of an individual spark, the flame, therefore, is always extinguished
above. The part below the spark is constant and steady.

On the Deportment of Solutions of Glauber's Salt on Reduction of Tempera-
ture.— As the physical processes in the so-called supersaturation of Glaubers
salt solutions have as yet found no sufficient explanation either from physi-
cists or chemists, it will not be uninteresting to our readers if we place be-
fore them the conclusions of Dr. F. Lindig, of Schwerin.

If a solution of Glauber’s salt, whether saturated or not, is allowed to
cool slowly, it contracts with diminution of temperature, like any other
body, as long as there is no crystallisation. But as soon as the first crystals
form in the clear solution, instead of contracting, it begins to expand, and

SCIENTIFIC SUMMARY.

95

continues to do so in proportion as the crystallisation proceeds. Hence the
density of the crystals forming is less than that of the solution from which
they form. Surprising as is this deportment of a gradually crystallising
solution of Glauber’s salt, that of a so-called supersaturated solution is still
more surprising and remarkable. If such a one by careful treatment is
cooled down to 0°, and then made to crystallise suddenly, the crystal cake
formed, which constitutes a compact solid mass, exhibits an extraordinary
increase in volume, and on further cooling to about 10° C. below zero, con-
tracts more and more. As in this condition of the original solution there
can be no question of a separation of crystals as in the former case, it seems
(like water below 4°) not to follow the law according to which bodies con-
tract by diminution of temperature.

GEOLOGY AND PALAEONTOLOGY.

The Entire Skeleton of a Mastodon has just been discovered in a peat-bed
near Troy. The jaw-bone was found near the surface. At a depth of about
50 feet the remaining bones were found. The tusks were very nearly 6 feet
long and about 9 inches in diameter. One of them, upon exposure to the
light, crumbled to pieces like clay, resembling that substance in appearance
and texture. The ribs, of which there were 14 found, are about 4 feet long,
the largest being 4 feet 9 inches. The upper jaw-bone is 4 feet 9 inches
long from the extremity of the mouth to the cranium, and across the fore-
head measures about 8 feet. So heavy is it that it was with difficulty four
labourers could move the mass. The sockets in which originally were
located the eyes of the monster are almost large enough to admit the head
of a man. The hip-bone is 5 feet long, and weighs 100 pounds ; the
shoulder-blades measure 2 feet 9 inches, and weigh about 50 pounds each.
The bone of the leg at the knee-joint measures 13 inches in diameter. The
vertebrae of the back-bone are 8 inches in diameter. The other fragments
found are in harmonious proportion to those already mentioned.

On the Distribution of Life Docks. — Mr. H. G. Seeley read a paper at the
late meeting of the Cambridge Philosophic Society upon “ The Laws Regu-
lating the Distribution of Life of Rocks.” Mr. Seeley stated that in all denu-
dation, whether marine or subaerial and fluviatile, the crystalline rocks which
underwent this process were again deposited in the following order : (1)
sand, (2) clay, (3) limestone j the second overlapping and appearing at the
junction, to be superposed to the first, and the third to the second. Hence
these deposits, which at first sight appeared to be successive, might in
reality be contemporaneous. Again, deposits were commonly assumed to be
contemporaneous when they contained the same fossils ; but upheaval and
depression would cause the fauna of any locality to move ; so that remains
of the same species might be deposited necessarily in different deposits. He
also considered species to be re-transmutable, and to be affected by the
physical conditions under which the animal was living. Therefore he main-
tained that strata could not be identified by these means, but by discovering
the physical conditions under which they were deposited, and by other

96

POPULAR SCIENCE REVIEW.

methods. At the same meeting Mr. Seeley read a paper on the Potton
Sands. — Applying these principles to the Potton Sands of Bedfordshire, he
considered that the lower deposits were of the same age as the Portland sands
of the South of England ; the middle fossiliferous seams of the age of the
Purbeck heds ; and the upper deposits of the Lower Greensand.

On some Points in the Structure of Xiphosura . — At a late meeting of the
Geological Society, Mr. W. Woodward, the accomplished editor of the
Geological Magazine, read a valuable paper on the above important palaeon-
tological subject. He pointed out that Professor McCoy’s tribe, Pcecilopoda,
was intended to include the Limuli, with Eurypterus, Pterygotus , and Beli-
nurus. Professor Huxley had already shown (in 1859) that this classification
was founded upon an erroneous interpretation of the fossils, then (1849)
only known in England by extremely fragmentary remains. Professor
MHoy’s classification was based on conjecture rather than on a minute
acquaintance with the anatomy of these extinct forms. The subsequent
researches of Professors Agassiz and Hall in America, Professor Nieszkowski
in Eussia, and the independent investigations of Mr. J. W. Salter and the
author in this country, have shown that a close relationship actually does
exist between the Xiphosura and the Eurypterida. Mr. Woodward then
gave a detailed comparison of the structure of these two divisions, which
he proposed to call suborders of Dr. Dana’s order Merostomata. He pointed
out that the Xiphosura were divisible into three genera: (1) Belinurus
[BailyJ, having five freely articulated thoracic segments, and three anchylosed
abdominal ones and a telson; (2) Prestwichia, a new genus, having the
thoracic and abdominal segments anchylosed together ; and (3) Limulus
[Muller], having a head composed of seven cephalic and one thoracic seg-
ments, followed 1 y five coalesced thoracic somites bearing branchiae, and
one or more coalesced apodal abdominal somites, to which is articulated the
telson. Although so great a dissimilarity exists between Pterygotus and
Limulus, yet in the genera Ilemiaspis, Exapinurus, and Pseudoniscus , we
have forms which, in the number of body-rings, are intermediate.

On the Dinosaurian Reptiles of South Africa. — Professor J. H. Huxley, in
a paper he read before the Geological Society, describes a portion of a right
femur 25* inches long, so that the entire femur may be safely assumed to
have exceeded 30 inches in length. The peculiar form of the bone and the
character and position of the trochanters leave no doubt of the Dinosaurian
affinities of the reptile to which it belonged, which must have been com-
parable, in point of size, to its near allies, the Megalosaurus and the Igua-
nodon. To the former of these it possesses the closest affinity, but differs in
the proportional size and form of its trochanters, and in its much heavier
proportions ; and the author proposes for , it the name Euskelosaurus
Brownii. Professor Huxley also described a portion of the distal end of a
femur, indicating another genus of large-sized Dinosaurian reptiles, the
characters yielded being to prove that it belongs to another genus than
Euskelosaurus .

Secondary Fossiliferous Deposits of New South Wales. — These have been
very carefully examined by the Bev. W. B. Clarke, who has recently given
a description of them to the Geological Society. It appears that until the
year 1860 secondary deposits were thought to be absent from Australia.

SCIENTIFIC SUMMARY.

97

Since that date, however, secondary fossils have been discovered by various
geologists. Mr. Clarke’s enquiries extended over the country near the
Maranoa river in Queensland, and the examination of specimens sent to him
from localities between there and the Flinders river have led him to believe
that there exist in that area various formations from the Triassic to the
Cutaceous series. It seems that the deposits on the eastern and western
sides of Australia are by no means identical.

Figures of British Fossils. — Mr. W. Hellier Baily, Palaeontologist to the
Irish Geological Survey, is issuing, or proposes to issue, in numbers, a series
of lithographs, illustrative of characteristic fossils. The work will consist
of tinted plates and explanations, but will be without letterpress. Those
who are familiar with Mr. Baily’s untiring industry in the pursuit of palaeon-
tology will know how to appreciate his new work. Each number will be
published separately, will contain ten plates, and will be sold at the moderate
price of five shillings.

Flint Cores from India. — General Twemlow has sent over from India several
specimens of the above, and with them a letter to the editor of the Geological
Magazine , asking for a notice of them. Accordingly Mr. John Evans has
examined them, and has offered his opinion upon them. They present the
appearance of cylinders which have a polygonal outline, and are the remnants
of flints from which flint weapons have been chopped off. It seldom happens,
Mr. Evans states, that a single specimen of flint is of so pure and homoge-
neous a character as to yield so many regular chips as those which Major-
General Twemlow has sent over from the Indus. The statement of the
discoverer that they were found in the bed of a river beneath three feet of
rock, Mr. Evans receives with some doubt, and he considers the specimens to
belong rather to what is called the Neolithic than the Palaeolithic period of
India.

Acalephce in a Fossil State. — Several very well preserved fossil remains of
the Medusidse have been discovered in the lithographic slate of Eichstadt
by Professor Iiackel, of Jena. The species more recently described by the
German savant belong to the family Rliizostemidse, the typical genus of
which is so frequently illustrated in zoological text-books. Professor
Hackel’s restorations seem to have been conscientiously made, and there is
every reason to think that ere long the study of fossil Medusidse may become
an important branch of palaeontology. — Vide Geological Magazine, November.

The Rocks of North Devon and Somerset. — Mr. G. J. Beete Jukes has
published a paper on the grouping of these deposits. Mr. Jukes takes as
his starting-point the country round Wiveliscombe, and describes the rocks
of the district reaching from that place north-west to the Brendon ' Hills,
and westward to Dulverton, including the valley of the Tone more to the
south. He has arrived at the following conclusions : — (1) There are three
areas of old red sandstone in this region, namely, a , the Quantock Hills j
b, the Porlock, Minehead, and Dunster area 5 and c, the Morte Bay and
Wiveliscombe ridge. (2) Each of these masses of old red sandstone dips
under a great mass of carboniferous slate. (3) The coal-measures, the carbo-
niferous slate, and the old red sandstone of Devon are contemporaneous with
the coal-measures, carboniferous limestone, and the old red sandstone to the
north of the Bristol Channel.

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POPULAR SCIENCE REVIEW.

Madrepores of the Infra-Lias of South Wales. — In a paper read before the
Geological Society, on November 21, Dr. P. Martin Duncan stated the fol-
lowing conclusions : (1) That the fossiliferous beds of Sutton, Southemdown,
Brocastle, and Eivenny, are important members of the series which intervenes
between the Trias and the beds containing Ammonites Hucklandi , Gryphcea
incurva , &c. and that which has been named the Infra-Lias. (2) That the
Mollusca and certain well-known species of Madreporana, which are grouped
together at Brocastle, have similar relations to each other in the Calcaire de
Valogne , in the zone of Ammonites Moreanus of the Cote d’Or, and in the
Gres de Luxembourg. (3) That the above-mentioned beds in Wales, consti-
tuting a coralliferous horizon, are the equivalents of the upper beds of the
French and Luxembourgian Infra-Lias.

Age of the Chinese Coalfields. — It will possibly surprise some of our
readers to learn that the greater part of the Chinese coalfield belongs to the
Mesozoic period. This has been recently demonstrated in the American
Journal of Science ; the author of the article having received several specimens
of the Chinese coal-fossils, has been enabled to determine that all the carbo-
niferous fossils are absent, and that most of the plants present are Podoza -
mites and Pterozamites, which are essentially Cycads.

MECHANICAL SCIENCE.

II. M. S. “ Water witch P This vessel, which has recently been tried, has
been built to ascertain the value of the new system of jet propulsion, intro-
duced bT; Mr. Buthven, to which we have before adverted in these pages.
The experiment is upon so large and costly a scale, and in the hands of men
so thoroughly competent to carry it out, that the value of the system will
doubtless be thoroughly investigated. We take the following particulars of
the vessel from Engineering , vol. ii. p. 315 (October 26), which contains the
most accurate description which has yet appeared. The “Waterwitch” was
designed by Mr. E. J. Peed, and has been built by the Thames Shipbuilding
Company. Her tonnage is 778 tons measurement, length 162 feet, breadth
32 feet, depth 13 feet 9 inches. She has a flat bottom, and is double-ended,
each end being fitted with a rudder. She is armour-plated for a length of
about 60 feet amidships, with 4|-inch plates on 10 inches of teak backing. The
propelling machinery was constructed by Messrs. J. & W. Dudgeon, accor-
ding to the plans of Mr. Buthven. It consists of a set of three cylinder
condensing engines, driving a centrifugal pump, by which the water is sup-
plied to the jets, which constitute the propelling apparatus. The revolving
wheel of the centrifugal pump is 14 feet in external diameter, and it has 12
arms or vanes curving upwards and outwards. From the wheel case the
water is conducted through two copper pipes, which leave the case tan-
gentially, and are led with a spiral curve to the jets at the side of the vessel.
The arrangement for directing the jets either forwards or backwards consists
of a large two way cock, placed at each side of the vessel just within the
delivering nozzles, and by turning these cocks the water can be delivered

SCIENTIFIC SUMMARY.

99

through either the forward or aft nozzles, or through one forward and one
aft nozzle at pleasure. The delivering nozzles are of brass, 2 feet 1 inch
by 1 foot 7 inches or about 452 square inches sectional area.

The engine has three cylinders 38i- inches diameter and 3 feet 6 inches
stroke.

The following results were obtained on the trial, the draught being 9 feet
9 inches and the lower edges of the jet nozzles being 8 inches below the
water level.

First run. A half knot tide against the ship ; speed, 8*276 knots; revo-
lutions of engines, 41 ; steam pressure, 24 lbs ; vacuum, 26 inches.

Second run. A half knot tide in the ship’s favour ; speed 9*549 knots;
revolutions of engines, 42 ; steam pressure, 25 lbs ; vacuum, 26 inches.

Mean spead = 8*912 knots.

It will thus be seen that the u Waterwitch ” attained a speed sensibly
identical with that of the a Viper,” a twin screw, armour-plated gunboat of
precisely similar tonnage, displacement, and engine power. Still the per-
formance of the “ Viper ” compared with that of other vessels can hardly
be considered satisfactory, and the most that can at present be assumed
is that the new system of propulsion is capable of attaining results equal to
the less satisfactory results with the ordinary screw propeller.

The Rev. J. A. L. Airey, M.A., has mathematically investigated the
theoretical conditions of the action of the jet. His calculations show that
only 18*82 per cent, of the indicated horses’ power is usefully applied in the
propulsion of the vessel; 18*33 per cent, is wasted in the residuary velocity
of the water ; and another 10 per cent, is probably consumed in engine fric-
tion, leaving 52*85 per cent, still unaccounted for.

Our own opinion is that a large part of the want of success is due to the
inefficiency of the centrifugal pump, which was not of the best, type, and
might be most materially improved by a more scientific disposition of the
vanes, and by the addition of Professor Thomson’s whirlpool chamber.

Steel Bridge. — A bridge of the inverted bowstring form, constructed of
puddled steel, has been erected by Major Adelskold at the Gotha Elf, in
Sweden. . The span is 137^ feet, and the total weight of the structure is only
50 tons. The maximum strain on the material is calculated at 8 tons per
square inch, and all the parts of the bridge were teste#?o 16 tons per square
inch.

Channel Bridge. — In addition to the tunnel schemes for carrying a railway
across the English Channel, Mr. McClean is reported to have proposed a
bridge.

Institute of Mechanical Engineers. — At the last meeting of this Society at
Birmingham, a paper was read by Mr. John Robinson on Seller’s self-adjust-
ing Injector for feeding boilers, a most valuable improvement on the Gifiard
Injector, which is now so extensively used, making it automatic with a
varying steam pressure. Also a paper by Mr. E. W. Webb on a curvilinear
shaping machine, for finishing the curved inner face of locomotive wheels to
a true circle.

Crumlin Viaduct. — This beautiful example of the Warren or triangular
girder, which had become dangerous from the loosening of the joints, con-
sequent on an insufficiency of bearing-area, has been thoroughly renovated,

YOL. YI. — NO. XXII. I

100

POPULAR SCIENCE REVIEW.

and the wooden flooring replaced "by an iron one. The structure is now
probably stronger than when first erected.

Parabolic Governor. — Messrs. Smith & Jackson, of Keighley, have pro-
posed a new form of pendulum governor, in which the balls are constrained
to move in a parabolic arc. In this arrangement the balls may remain at
any position in their range, and the governor revolve at one and the same
speed ; in other words, the governor cannot possibly continue to run faster
or slower than its proper fixed speed, when the balls are anywhere within
the limits of their range : and consequently, the range being made sufficient
to completely shut or open the throttle -valve, the engine cannot possibly
continue to run faster or slower than that fixed speed, without in the one
case opening the valve wide, in the other closing it. This obviates the
objection to the ordinary governor, which has a special rate for every
position of the balls.

Fairlie’s Locomotive for Steep Inclines. — The necessity of greater adhesion-
weights in locomotives has led to the coupling of four, and even in extreme
cases of six, pairs of wheels. For such engines, French engineers have for
some time adopted four cylinders, grouping the wheels in two sets. Mr.
Fairlie has now advanced one step further, and has adapted the four-cylinder-
engine to railways with sharp curves, by arranging the two sets of wheels in
two swivelling bogie frames. An engine of this description, built for the
Queensland railways, was tried in August on the St. Helen’s bank, which
has an average gradient of 1 in 80. Up this bank the engine took a train
weighing altogether, inclusive of the engine, 194 tons, at a speed varying
from 24 to 13 miles per hour.

MEDICINE.

On the Movements of the Heart. — In a recent memoir Dr. Sibson describes
his experiments on the movements of the heart, which were made on the
ass under the influence of wourali, and on dogs subjected to chloroform.
He found that the contraction of the ventricles takes place in every direc-
tion towards a region of rest, which in the right ventricle corresponds with
the anterior papillary muscle in the left ventricle, with a situation about
midway between apex and base. Simultaneously with the universal con-
traction of the ventricles there is universal distension of both auricles, the
pulmonary artery and the aorlse. The total amount of blood contained in
the heart and great vessels is the same during both systole and diastole.
During the ventricular contraction, however, the distribution of the blood,
lessened towards the region of the apex, balances itself by being increased
in that of the base, since the auricles and great vessels are enlarged, not
only towards the ventricles, but also outwards and upwards. During ven-
tricular dilatation the reverse takes place.

State of the Eye in Hemeralopia. — Signor Quaglino, of Pavia, has published
the results of thirty cases of hemeralopia. The alterations he observed are
briefly as follows: — (1) Whitish-grey haziness of the whole retina, espe-
cially around the disc, and along the retinal vessels after invading the disc
itself. (2) Manifest congestion of the veins, which are tortuous and filled
with blackish coagulated-looking blood. (3) The central arteries often

SCIENTIFIC SUMMARY.

101

enlarged in tlie region of the disc. (4) In recent cases the disc looks red or
roseate. (5) The obscuration of the retina ceases, hut the arteries and veins
become smaller and the contours of the disc lose their regularity, and are
fringed by streaks of pigment. — Vide Ophthalmic Review, October.

Development of Epithelial Cancer in Internal Organs. — Dr. Otto Weber
finds from researches made in the liver and lungs, that secondary cancroid
deposit exists in internal organs much more frequently than is believed. The
epitheliomata in internal organs, he says, are developed at the expense of the
nuclei of the interstitial connective tissue, and not of the proper epithelial
cells of the organs. He gives several instances of the co-existence of epi-
thelial cancer and tubercle in the same organ.

Structure of the Kidney. — M. Chrzonszcewsky combats Henle’s ideas on
the structure of the kidney. He injects carminate of ammonia into the
jugular vein of a rabbit ; the carmine passes into the vessels and thence into
the uriniferous tubes and the urine. To colour the vessels alone he ties the
renal veins immediately after injecting the jugular, then the artery; to
colour the uriniferous tubes only, he ties the ureter, and injects through the
renal artery a saline solution, which removes all the colouring matter depo-
sited in the vessels of the kidney. The principal results at which he has
arrived are the following : — The uriniferous tubes end in three ways — in
anastomoses, in culs-de-sac, and in the Malpighian corpuscles. The anasto-
moses, which are very numerous in man, in the calf, and in the pig, are
met with chiefly in the cortical substance. The termination in cul-de-sac
is very rare, but there is no doubt of its existence. The Malpighian cor-
puscles (or rather capsules) are continuous with the tortuous tubes alone,
and each with only one. The Malpighian capsule is lined with pavement-
epithelium ; the internal surface of the glomerulus of vessels is also covered
with epithelium, but of larger cubic cells, more resembling the tortuous
tubes. The Malpighian capsules communicate with the flexuous tubes, and
through them with the straight tubes ; and all may be injected through
the ureter. In the looped canals described by Henle two kinds are to be
distinguished : 1. Some described already by Perrein, found in the peri-
pheral portion of the medullary substance, are merely loops of flexuous
tubes burying themselves in this substance ; 2. Others, reaching the sum-
mits of the pyramids, are merely vessels.

Production of Anencephalic Monsters. — M. Dareste, well known for his
researches in teratology, has published a very able paper on the cause of
these monsters. It appears that two theories have hitherto been framed to
account for these phenomena, and it seems that though those two hypotheses
apparently contradict each other, M. Dareste’s discovery has harmonised
their more important points of difference. It was thought by Haller and
Morgagni that the cause lay in the existence of a dropsy of the spinal cord,
which tended to destroy the nervous substance. Geoffrey St. Hilaire, on the
other hand, looked upon the cause as an arrest of development. Both hypo-
theses are in some measure correct, according to the results of M. Dareste’s
enquiries ; but Haller and Morgagni erred when they said that the effusion
destroys the nervous substance. In point of fact, M. Dareste has discovered
that the effusion appears before the nervous substance, and thus hinders its
development. But this distinguished physiologist has gone a step further

102

POPULAR SCIENCE REVIEW.

than his predecessors in demonstrating that the effusion in question is the
result of an extremely anaemic condition, which is the first unusual symptom
that presents itself. In some instances he has seen this dropsy affect both
true and false amnion. — Vide Lancet , u Record of Sciences.”

Homological Relations of the Scapula and Ilium. — Mr. St. George Mivart
has j ust written an important paper upon the Echidna Hystrix, in which we
find some novel suggestions as to the relations of the scapula and ilium.
Mr. Mivart says that when we place the anterior and posterior limbs in a
position for fair comparison, the two extensor borders being outwards, the
elbow being drawn outwards and forwards, and the knee outwards and
backwards, the suggestion naturally occurs that the bones from which they
are suspended are rotated, as in fact they are naturally in Galeopithecus.
This being done, the coracoid seems to answer to what Mr. Mivart believes
to be its true liomotype, the ischium ; also the suprascapular notch seems to
repeat the sacro -sciatic one, while the spine of the ischium with the lesser
sacro-sciatic ligament attached to it “ recalls to mind the prominence from
the base of the coracoid with its coracoid ligament.” Mr. Mivart thinks
that the spine and acromium of the scapula are unrepresented in the ilium.
In the echidna the part of the scapula which gives origin to the sub-
scapularis looks backwards and outwards ; hence Mr. Mivart enquires, Are
we to regard this as the natural position, and consider the position of the
bone in the higher animals as exceptional? Mr. Mivart concludes his
memoir with the suggestion that they should be regarded as columnar bones,
a character which they exhibit in a high degree in chelonians.

Duality of the Heart. — According to M. Dareste, the primitive duality
of the heart is the immediate consequence of the primitive duality of the
anterior lam hue of the vascular area. In reality, the blastemae, which
farther on will form the heart, at first make their appearance as two small
oblong masses, observable at the lower internal portion of each of these
laminae, quite close to the point where they become united to form the
apex of the retreating angle. These two blastemae are completely sepa-
rated, like the laminae from which they spring. At a later stage, when the
two laminae become united on the median line, the two cardiac blastemae
whose development has kept pace with that of the laminae, also approximate
on the median line, and speedily unite into a single mass, which forms
what embryogenists have thought to be the primitive condition of the
heart. Nevertheless, an indication of the primitive duality is still for some
time to be met with ; it is a groove which is situated at the anterior por-
tion of the organ, and which arises from the fact that the junction of the
two cardiac blastemae has gone on from behind forwards, like those of the
laminae of the vascular area, which serves to support them. — Yide I! Institute
November.

Origin of the Lymph Vessels. — M. Chrzonszcewsky asserts that the finer
lymph -vessels take their rise from the anastomosing processes of the cor-
puscles of the connective tissues. He made observations on the peritoneal
coat of fowls whose ureters had been tied some hours before death, and
found that when the delicate serous membrane was examined in glycerine,
the connective tissue corpuscles were filled with a finely granular mass of
urates, and that the lymph-vessels were also filled with the same material

SCIENTIFIC SUMMARY.

103

The union of the processes of the connective tissue corpuscles with the
lymph-vessels could he distinctly seen. That the granular contents of the
corpuscles and lymph-vessels were really urates was proved hy the well-
known reaction with nitric acid and ammonia. The author concludes, from
these experiments, that the urates arise in the connective tissue, and are
carried away from it hy the lymph-vessels. — ( Virchow's Archiv ., Jan. 1866).

A new Narcotic : Wrightia antidysenterica. — M. Theodore Husemann has
been studying the effects of this plant. It is of Indian origin, and it3
hark and seeds are much employed in the East Indies as a remedy for
dysentery, diarrhoea, indigestion, fevers, and bilious affections. M. Huse-
mann has experimented on toads, frogs, pigeons, and rabbits. He finds that
doses of from 150 to 200 milligrammes of alcoholic extract of the seeds is
all but poisonous to batrachians, and that these animals never resist doses
of from 250 to 300 milligrammes. Doses of from 2-5 to 4 grammes kill
pigeons and rabbits, while rather smaller doses cause only a certain stupor.
The effects of the poison become generally visible on whales about a quarter
of an hour after its administration, and on pigeons and rabbits after from
thirty to forty-five minutes j death takes place in the latter case at from
three to four hours and a half. At first a paralysis of the muscles is appa-
rent, then a suppression of the reflex motions. There is no noticeable
alteration in the pupillary diameter, nor in the movements of the heart.
Death results from the paralysis of the thoracic muscles.

Physiological Action of Helleborine and Helleboreine. — M. Marine has been
making some physiological experiments on batrachians, birds, and mammals,
with the two active principles of hellebore, which he calls helleborine and
helleboreine. The helleboreine acts on the heart in the same manner as
digitalis. Used subcutaneously it acts in much smaller doses than digi-
talis, and similarly produces slackening of the pulse. In stronger doses, on
the contrary, it causes an enormous acceleration, soon followed by a sudden
paralysis of the heart. With regard to the respiration, its acceleration or
slackening is in an inverse ratio to the change of the heart’s beat ; it is
rapid at the commencement, slow at the end. Helleboreine produces vio-
lent vomitings and dysenteric diarrhoea, accompanied by acute pains, in
birds, dogs, and cats. It singularly excites the secretion of urine, and pro-
duces hypersemia of the pelvic organs, particularly in the female. After
making allowance for its influence on the circulation and the respiration, it
acts also on the nervous system, producing tremors and sometimes convul-
sions. Helleborine. — Helleborine has the property, in common with helle-
boreine, that it does not act on the external teguments, and that it -sharply
irritates the intestine.

Presence of Copper in the Animal Organism. — M. Blasius, by minute ana-
lyses, has established the presence of copper in the tissues of mammals.
Some of M. Blasius’ results are embodied in the following table : —

Ox liver

Weight

Grammes.

. 1865

Proportion of Oxide
of Copper to the 100.

0-0007

Sheep’s liver

. 474

0-0010

Liver of a man

. 1440

, inappreciable

Spleen of do

. 101

0-0007

Kidneys of do

. 200

0-0007

Heart of do

. 200

0 0007

104

POPULAR SCIENCE REVIEW.

The Poisonous Action of Digitaline. — Dr. Brunton of Edinburgh, in his
prize thesis, says this substance acts as a diuretic even in health. Poisonous
doses first occasion diminished frequency, hut increased strength of the car-
diac pulsations, together with contraction of the capillaries. The slackening
of the heart’s speed is due to the direct action of poison upon the heart, and
not to the increased resistance offered by the contracted capillaries. After
a short time the pulse becomes irregular, the capillaries dilate, the arterial
tension diminishes, and syncope is apt to supervene. Lastly, the pulse
becomes very rapid, and stoppage of the heart in a state of contraction soon
follows.

The Action of Aconitine. — Dr. Achscharumow arrives at the following con-
clusions : — 1. Death is not due to paralysis of the respiratory muscles, but to
stoppage of the heart from paralysis of its motor ganglia. 2. The first effect
is irritation of the medulla oblongata, which is communicated to the vagi.
3. Paralysis of the vagi supervenes, from continued irritation. 4. The tem-
perature and blood-pressure are lowered. 5. The peripheral nerve endings
and trunks are entirely paralysed. 6. Keflex function of the spinal cord
remains intact. 7. The brain is unaffected. 8. It has no local action on the
pupil. — Vide Reichert and Dubois Reymond's Archives , No. 2, 1866.

METALLURGY, MINERALOGY, AND MINING.

Reported Discovery of Coal in South Australia. — It is asserted that a mine
of anthracite has been discovered at Port Lincoln, South Australia. Mr. Hodg-
kiss, the owner of the land on which the deposit has been found, has claimed
the reward of £5,000, offered three years ago to anyone finding a coal-mine
in South Australia.

Roasting of Grey Copper-ores in Hungary. — At the Stefanshuette works
for the smelting of the grey copper-ores, they use of the yellow ores only
poor quartzose ore, which is necessary for fluxing. The processes, there-
fore, have a character quite different from that in other places, where the
grey copper-ores form only a small part of the materials to be melted. One
of the main progresses in the last years is the production of metallic antimony
from grey copper-ores, since more than one-half of the regulus antimonii,
which comes in the market from Hungary, is now produced from these
ores.

Production of Steam by Employment of Petroleum. — Notwithstanding the
assertion of the American Naval Commission, that no advantages are to be
derived from the employment of petroleum as a substitute for coal, we find
that the English Government is taking up the enquiry in a serious spirit. A
contemporary informs us that Mr. Richardson, who is instituting experiments
in “burning petroleum and other oils, with a view of superseding the use of
coals for steam purposes, has received permission from the Lords of the
Admiralty to use a service boiler in Woolwich Dockyard for one week, in
order to demonstrate the advantage of shale-oil as fuel. The trial has been
requested by a number of shale-oil manufacturers in Wales and Scotland, and
some scientific persons.

SCIENTIFIC SUMMARY.

105

Corrosion of Ships. — Mr. Daft’s proposition to protect the iron by zinc, by
placing an intervening thickness of felt between these two metals, and which
plan was approved of by the late Admiralty, has been tried. A trial of its
efficiency obviously involved a question of time. Sixteen months having
elapsed since the commencement of this experiment, the sheet of iron pro-
tected by a sheet of zinc, and a sheet of felt between the two, was raised from
the action of the sea- water in Portsmouth Harbour, in the presence of the
visiting Board of Admiralty. The result was satisfactory. The subsequent
experiment, which brought the two metals in direct contact, was also highly
satisfactory in its result.

Hardness of Silver. — Mr. Mathey, assayer at Loda, has shown that in even
hard silver there is neither tin, lead, nor any other injurious metal. Its
hardness, he asserts, is due solely to the high temperature at which silver is
cast. By letting the crucible cool till a slight solid crust is formed on the
surface of the fused metal, and casting at this moment, a soft silver with a
brilliant cut is obtained. — Vide Dingier' s Polytechn. Journal.

Plow to use Nitroglycerine. — In another number we gave a general account
of the properties of nitroglycerine, and of the mode of employing this explosive
substance ; but as a recent and exact description has been published by Mr.
E. Kopp, we translate it for our readers. Suppose, he says, it is desired to de-
tach a layer of rocks. At a distance of from 2 -5 to 3 metres from the out-
side, a mine-hole is dug of about 5 to 6 centimetres diameter and 2 to 3
metres depth. After having cleared this of dirt, water, and sand, 1,500 to
2,000 grammes of nitroglycerine are introduced, by means of a funnel. A
small cylinder, of iron, cardboard, or wood, about 4 centimetres in diameter
and 5 to 6 centimetres in height, is then introduced and filled with ordinary
powder. This is fixed to a wick or ordinary mine-fuse, which penetrates
into it to a certain depth, to assure the inflammation of the powder. By
means of the match on the fuse, the cylinder is lowered ; and by the feel
the moment can be easily judged at which the cjdinder reaches the sur-
face of the glycerine. The match being then held firmly, fine sand is run
into the hole until it is quite full. It is useless to compress or tamp the
sand. The match is cut a few centimetres above the orifice, and set fire to.
In eight or ten minutes, the burning of the wick having reached the cylinder,
the powder inflames. A violent shock ensues, which instantaneously
explodes the nitroglycerine. The explosion is so sudden that the sand has
no time to be projected.

MICBOSCOPY.

On the Improvement of the Compound Microscope.— In the Microscopical
Journal for October, Mr. Fred Curtis gives the following remarks on the im-
provement of the Compound Microscope, as sequel to a contribution of July,
1863. He observes : u Concave mirrors in place of lenses in the eyepiece,
so inclined as to reflect the body of rays into the form of a figure of 4,
would aflord a convenience of manipulation almost irrespective of the di-
mensions of the instrument. If approved, a mirror as objective also might

106

POPULAR SCIENCE REVIEW.

afford additional mechanical facilities. On a smaller scale the form of the
letter N might he preferred. Attached to each objective should he a length
of tube twice or more its focal distance. To avoid moving the body of
the instrument, I would apply the adjustments to the stage. The experi-
mental instrument of glasses described in 1863 performs admirably, on a
white enamelled watch-case, on the surface of a flea, on solid deal, on
mouse’s hair, and on the surface of the pollens of whin, broom, and geranium,
without condenser. The field is remarkably flat, and available at every
part.”

Smith's New Growing Slide. — Dr. John Barker, of Dublin, has devised an
ingenious modification of Smith’s new growing slide. It consists of a shallow
glass box, as in Smith’s, but both upper and lower plate having cut out of
each a circle of about an inch in diameter; and a piece of glass tubing
set therein and cemented, so as again to hermetically close the box. Im-
mediately over the aperture thus made through and through the box, a
circle of glass, a shade wider in diameter and rather thinner than an ordi-
nary slide, is cemented, thus again closing the aperture through the box at
one of the surfaces. The upper surface of this circle of glass forms the table
on which the object for examination is placed. At the right-hand side, just
beyond the edge of this circle of glass, and near the lower edge of the box,
a small hole is drilled through the upper plate of the box, which is the
feeding hole for the water, which is introduced into the box by a small
opening ground away at the lower right-hand corner. The object is now
covered by a square of thin covering glass in the usual way ; one angle of the
cover extends at the right-hand side beyond the circular table, and reaches
so far as to cover the little feeding aperture in the box, and the flow is
established. There is a little strip of glass cemented at the lower side to
prevent the square cover slipping. This plan has the advantage of allowing
the light to come up from the mirror, not through a stratum of water, how-
ever thin, but directly through a thin plate of glass, permitting, too, the
use of the achromatic condenser if needful. Dr. Barker stated he had found
this plan to act very well.

A Handy Cabinet for Microscopic Objects. — Mr. Collins, of Great Titch-
field Street, has sent us a specimen of a slide-cabinet, which is certainly a
marvel of simplicity, cheapness, and efficiency. It consists of a sort of card-
board box provided with a cover, and whose front side, if we may use such
an expression, lets down. Opening the box we see six neat papier-mache
drawers, each of which contains six compartments for slides, which are laid
upon the flat. The great advantages of this case are : the economy of space,
the convenience with which any of the drawers may be removed, the ease
with which the names of the various objects may be observed, and the ex-
treme lightness and portability of the case. We believe the cabinet was
originally designed by Mr. Piper, and we commend it to the notice of our
readers.

*

PHOTOGEAPHY.

Mr. Woodbury's Printing Process. — Certain of our contemporaries long
since promised specimens of this new process, which have not up to the

SCIENTIFIC SUMMARY.

107

present time been forthcoming. Doubts have therefore been publicly ex-
pressed as to its practical value. We have now reason for believing that the de-
lay arose in each such case from Mr. Woodbury’s desire to effect contemplated
improvements before issuing other prints to the public, and which improve-
ments have but recently been accomplished. The difficulty experienced of
obtaining labourers sufficiently skilled to ensure the production of a large
number of prints, possessing uniform excellence, has been overcome by substi-
tuting metal rollers for flat plates and causing them to revolve rapidly with a
self-inking arrangement. Thus mechanical means do perfectly that wherein
hand-labour had not proved satisfactory, and the prints are produced with a
rapidity and certainty such as we obtain with the type-printing cylinder used
in calico and newspaper printing. Another proj ected improvement is that
of substituting ink of the kind used in ordinary printing for the pigmented
gelatine, and this improvement, which we believe to be of vital importance,
is, we are told, in a fair way of being accomplished. Several new applica-
tions of this important process have also been discovered. One is that of
printing photographs on glass to serve as transparencies, etc. for decorative
purposes, and for exhibition as magic-lantern slides ; and others exist for
transferring the photograph to wood, stone, ivory, or metal. It is also used
for producing permanent cartes de visite at the very moderate cost of 9s. per
hundred, after an outlay of twelve shillings for the metal intaglio. Attempts
have been made to blend this process with that of chromo-lithography, but
judging by the dull, flat, horny-looking specimen shown at the South Lon-
don Photographic Society, a very slight degree of success has attended it,
although some ill-advised speculator has, we understand, made such appli-
cation the subject of a fresh patent. The process patented is, first, that
of transferring the photograph to the lithographic stone ; secondly, that of
printing it in colours in the usual way ; and thirdly, that of printing the
photograph again over the coloured impression by the Woodbury process.
The small value of the patent, and the objections to such a tedious inartistic
roundabout process, are too palpable to need pointing out.

Another New (?) Lens. — Mr. J. Traill Taylor, a gentleman who has intro-
duced many valuable practical suggestions and improvements in a peculiarly
quiet unostentatious way, in the April of 1864 read, before the Photographic
Society of Scotland, an optical paper, in the course of which he pointed out
how, by altering the arrangement of Petzval’s compound orthoscopic lens,
the depth of its defining power could be very largely increased, in combina-
tion with a large field flat without a diaphragm. The only sacrifice made
in this case was that of the microscopical degree of sharpness, which artists
call hardness, and which gives photographs, more particularly when stereo-
scopic, that strangely unnatural and rigid appearance which is more sugges-
tive of metal casts than of natural effect. This paper was duly published,
and in photographic pages ; but those critics who have no way of judging
the value or merit of an invention but by what the inventor may please to
claim for it himself, gave the discovery no good word, and so it speedily
passed from their remembrance. But at the last meeting of the u London
Photographic Society,” the same improvement, effected by identically the
same means, viz. the introduction of spherical aberration, was again brought
forward by an optician, who awarded the merit of its discovery to a gentle-

108

POPULAR SCIENCE EE VIEW.

man who, at the time Mr. Taylor’s paper was read, edited a photographic
contemporary. In this case, however, the reader of the paper was by no
means backward in the use of u varnish,” and verily he received his reward.
The Journal of the Photographic Society, in its last issue, speaks of u the
new (?) lens ” — under which name it is already advertised for sale — as “ an
optical discovery, the importance of which cannot be overestimated,” and
11 a service equal to that which Petzval did to photography itself in ren-
dering it, so far as optical instruments are concerned, a thing at all
possible ! ” If this is true, Mr. Taylor has reason to be proud.

A New Paper. — We believe that the use of collodio-chloride was intro-
duced by Captain Dixon, and was first publicly announced, in connection
with a new process, in the Photographic News, April 26, 1861. Among the
various trifling modifications, and consequent applications, since introduced
by photographers — each of whom has laid claim to the full merit of an
original discovery and invention — the more recent is found in connection
with a new paper for photographic printing, called u Leptographic.”
Numerous and valuable advantages have been claimed for this paper by the
French company interested in its sale, but it must be remembered that if it
is the collodio-chloride process, as experiments appear to demonstrate, in
yet another of its various modifications — which, however, the manufacturers
deny — all the disadvantages which have been urged against the one process
are still in full force against the other. The Leptographic process has been
successfully used to give a photographically sensitive surface to wood, canvas,
leather, ivory, silk, and other surfaces ; and is said to be specially suitable
for enlargements. The paper is issued ready sensitised, and prints are pro-
duced on it with great rapidity.

Photographs in Natural Colours. — A Photographic Canard. — We believe
the announcement — which our readers may remember — of a murderer having
been convicted by his image being photographed from the retina of his
victim’s eye, once made with so much circumstance, emanated from a foreign
correspondent to the Morning Post. Although the Lancet clearly demon-
strated the extreme absurdity of the paragraph, yet it went the round of all
our English papers, and after travelling abroad came back to us again, of
course considerably augmented. The Morning Post has more recently been
equally successful in starting a similar canard on its travels, through its Paris
correspondent, who stated that M. Chambray, a French photographer, had
discovered a means of producing photographs in natural colours, and declared
that he, the Paris correspondent, had himself carefully investigated the
wonderful process, and was satisfied and delighted with the perfection of
what he called u the great chemical and art event of the day.” This wonder,
having been duly echoed and re-echoed, created quite a sensation amongst
the credulous, and induced the Paris correspondent of the British Journal of
Photography to investigate the matter, when it turned out that M. Chambray
laid no claim to any such discovery, and that the supposed photographs in
natural colours were merely ordinary photographs coloured at the back and
rendered transparent.

M. Claudefs Process, as described in our last, has been placed before
the Photographic Societies of London and Paris, and the opinions we
expressed concerning it have been confirmed by the general opinion of the

SCIENTIFIC SUMMARY.

109

photographers who attended these meetings. At the London Society, Mr.
Mayal, Mr. Jahez Hughes, and others, condemned the thing both in principle
and practice, and the President of the French Society wound up the un-
favourable opinions expressed by stating that it was not in the direction M.
Claudet had pointed out that photographers could hope to find real progress.

Presentation of Medals. — The long-promised medals of the London Photo-
graphic Society have at length been awarded as follows: — To Roger Fenton,
as Founder of the Society ; to Lady Hawarden, for artistic and photographic
excellence (two medals) ■ to H. P. Robinson, for 1 composition ’ photography;
and to Messrs. Claudet, Williams, Joubert, England, Bedford, Thompson,
Maddox, Toovey, Buxton, Macfarlane, Mudd, Lieut.-Col. Stuart Wortley,
and Major Gresley.

Magic Cigar Tubes. — A toy application of photography has been intro-
duced in the shape of cigar- tubes, on which, when smoked, a photograph
gradually appears.

Permanent Photographs. — Messrs. Tichbourne and Robinson have ascer-
tained that chloric and perchloric acids completely oxidise weak solutions of
hyposulphite of soda, and on this principle base the following process.
Prepare a solution of twenty-four grains of chlorate of baryta in each ounce
of water, and add to this quantity twenty minims of perchloric acid (of
about 12 per cent.). This is the eliminating liquid. Take a porcelain or
other dish and place in it a pint of hot water, then add two ounces of the
above solution. The bath is now ready. Having washed the prints suffi-
ciently in the ordinary way, plunge them into the warm eliminating bath, and
let them remain there for an hour or so. They afterwards need only to be
washed with plain water, in order to cleanse the print, then to be dried and
mounted.

Mr. Sioan's Carbon Process. — At the meetings of the Photographic Socie-
ties some very attractive and beautiful examples of this process have been
exhibited, speaking volumes for the perfection of its results. The inventor
does not intend to charge for working his process, but will grant its use to
any photographer who may choose to purchase the materials. One of the
chief and best features of the process, in regard to the reproduction of works
of art, is the fact that drawings in chalk or monochrome may be repro-
duced, not only with the faithfulness of a photographic fac-simile, but in the
very material of the original. Thus a chalk drawing, red or black, is
reproduced in chalk, a sepia or bistre drawing in sepia or bistre, &c. The
paper is prepared in continuous lengths of 12 feet, coated with gelatine and
pigment, is rendered sensitive by immersion in a saturated solution of
bichromate of potash for one or two minutes. It is then dried and exposed
either to the enlarged image of the solar camera or in contact with the
negative, on the pigment side. Then it is mounted by the aid of a solution of
india-rubber, pigment side down, on a piece of white paper, and both are
next dried. After being rolled, the papers thus adhering are immersed in
tepid water for about ten minutes, when the gelatine will become softened
and the original paper can be removed, leaving the pigment attached to its
second support by the india-rubber solution. By increasing the heat of
the water the unaltered pigment and gelatine dissolves away, and the
picture is completed. Washing in cold water removes the traces of chromic

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POPULAR SCIENCE REVIEW.

salt, and after drying, a coat of clear gelatine brings to tbe next process that
of transferring, which is accomplished by placing a damp mounting board
on the gelatine surface and passing the two through a rolling press. This done,
when quite dry a piece of cotton wool saturated with benzole rubbed over
the surface of the paper attached to the benzole, softens the latter, and
admits of the former’s removal.

Photography and Navigation. — A Novel Application. — M. Carradi of Mar-
seilles proposes to register the path of a ship, and its various tackings and
evolutions, by means of photography. For this purpose he has contrived an
instrument which he calls a “ loxodograph,” which consists of a compass
placed below the ordinary ship’s compass, so as to occupy the same relative
position in the ship, and so that it can be compared from time to time with
the normal instrument. Underneath the secondary compass is some simple
clockwork, having for its object the unrolling of a band of sensitised paper,
of a width equal to the diameter of the card of the compass. This paper is
placed horizontally under the compass, and unrols, longitudinally following
the axis of the vessel. Underneath the disc of the compass, but above the
paper, and placed at the north pole, is a lens, which projects a luminous
point upon the paper below. Thus, if the ship pursue a straight line, from
north to south, for example, the luminous point will be thrown upon the
paper, and trace a straight line also from north to south ; if, on the
contrary, the ship move in an irregular broken course, the bright point
will be shown on the paper in a line of the same character, seeing that the
paper follows the ship’s movements, whilst the luminous point remains
stationary at the north. We extract this description from the British Journal
of Photography.

Something Sensational. — A strange story is told in Les Mondes. A Dr.
Marina, to advertise a method he had invented of preventing decomposition
after death, had operated upon the body of a deceased literary man, named
Pietro Martinis, who died on February 17 last. On the body being dug up,
on June 17 last, it was so supple and life-like that it was dressed up in the
author’s u habit as he lived,” taken to a glass room, and photographed.

PHYSICS.

New Instrument for Registering the Speed and Pressure of the Wind. — Mr.
John Browning has nearly completed, under the supervision of the As-
tronomer Boyal and Mr. Glaisher, a set of instruments for the above-men-
tioned purpose. The first, for registering the force of the wind, consists of
a circular plate of metal, of a diameter equal to two square feet in area,
supported by eight tempered steel springs. When the wind impinges on the
circular plate the springs are brought consecutively into action, the stronger
coming into play before the weaker have received any strain. The plate is
kept constantly facing the wind by means of a direction- vane. From the
plate a fine flexible wire is carried down through a hollow pillar which
supports the vane, the whole apparatus being in a room below. The wire
governs the motion of a pencil, which is made to traverse a table covered
with slate, on which is strained a sheet of paper marked with the hours.

SCIENTIFIC SUMMARY.

Ill

This table is moved by clockwork, and the pencil being regulated by the
pressure-plate registers on the paper the pressure of the wind during every
portion of the twenty-four hours. The instrument, which is capable of
registering as light a pressure as even two or three ounces on the square foot,
will in strong gales have to withstand a force of 40 lbs. to the square foot.
— Times , September 13, 1866.

On a Means of Weakening the Intensity of the Sun's Rays at the Focus of
Telescopic Object Glasses. — M. Leon Foucault proposes to alter the plan
hitherto adopted for this purpose. Tie proposes to deposit a layer of metallic
silver on the outer surface of the object-glass, by the means he has already
so successfully adopted for silvering the concave glasses for reflecting tele-
scopes. The metallic coating, -whilst it possesses so brilliant a lustre, has
also a transparency and limpidity which is comparable to the finest coloured
glass, and as it may be regarded as a surface devoid of thickness, its addition
to the object-glass will not interfere with the accuracy of its surface. By
its means the instrument is protected against the heat of the solar rays,
which are almost entirely reflected back towards the sky, whilst a minute
quantity of blue light only penetrates through the metal, and is refracted in
the ordinary manner, and forms at the focus a steady and clear image which
I can be observed without injury to the observer’s sight. The contour of the
solar disk is projected sharply against a black sky, the spots are marked with
! precision, and the faculse, as well as the decrease of light towards the edge
j of the sun, are distinctly shown. The true colour of the sun is a little
1 altered, owing to the preponderance of blue rays ,- but the gradations of in-
tensity are well preserved, so that no detail is lost, whilst the eye after a
' short time becomes accustomed to the blueness, and does not observe it.

The only drawback appears to be that this plan necessitates the sacrifice of
, an instrument, at least for a time, and the question appears to be, is the
object to be gained worth the cost P M. Foucault thinks that it is.

On a Neiu Kind of Acoustic Sand-Figures, and their Application to deter-
mine the Velocity of Sound in Solid Bodies and Gases. — Dr. Kundt adopts the
following proceedings to determine the velocity of sound in solid bodies,
j He inserts a rod of the substance of a given length some little distance in a
glass tube about four feet in length, and three-quarters of an inch in
diameter, containing a little lycopodium and with stoppers of cork. The
rod pushes the cork stopper before it, and is steadied in its position by a
shoulder of cork where it enters the glass tube. The note of the rod being
now educed is propagated to the air in the tube, and sand-waves are pro-
duced, from the length of which, compared with that of the soimding rod,

' the velocity of sound in the solid may be deduced. Dr. Kundt’s experi-
ments give for the velocity of sound in brass, 10-87 $ steel, 15-345 ; glass,
15*25 ; copper, 11-96. — Vide Poggendorjfs Annalen.

On the Diffusion of Gases through Caoutchouc. — Professor By he finds that
j when hydrogen gas is passed through india-rubber tubes it always contains
| traces of air and aqueous vapours. MM. Aronstein and Sirks examined
| this more fully, and found that common vulcanized, brown de-vulcanized,
; and pure non- vulcanized caoutchouc were all easily pervious to hydrogen,
1 but that they could be rendered impermeable by a coating of asphalt
dissolved in coal-oil.

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POPULAR SCIENCE REVIEW.

On a Means of Utilizing the Phenomena of Super saturation. — M. Jeanuel
suggests that this phenomenon may he utilized in the purification of sul-
phate of soda and other commercial salts. For sulphate of soda, proceed as
follows: — Take 300 grammes of this salt and 100 grammes of distilled
water ; dissolve at a temperature of 33° in a glass flask, and while this is
going on, arrange a filter in a funnel and pour through it 500 grammes of
warm water at about 50°. Then place the funnel on a wide-mouthed flask
well rinsed with distilled water, pour the warm saline solution on the filter,
and cover it with a plate of glass. The solution will entirely pass through
without crystallizing, and will remain liquid in the flask even after cooling.
When the funnel is removed, the solution, exposed to the air, rapidly
crystallizes and becomes heated. When quite cold, decant the mother
liquor. Sulphate of magnesia, sulphate of zinc, and carbonate of soda may
be purified in a similar manner. The acetate and tartrate of soda, soluble
in their water of crystallization at a temperature below 100°, may be easily
filtered by this means. This process is not applicable to alum. M. Jeanuel
proposes to use this phenomenon as a means of separating salts ; thus, dis-
solve 335 grammes of nitre and 300 grammes of alum in 100 grammes of
water j allow the mixture to cool without exposure to the air, and the nitre
will crystallize out, whilst the alum will remain in a state of supersatura-
tion. The separation of the two salts can thus be effected by decantation.

The Earth and Moon in Collision. — Mr. James Croll, who some time since
asserted that owing to peculiar solar and lunar action the above extraordinary
condition will eventually take place, has just published a paper reasserting
the truth of his proposition. The theory was opposed by the Astronomer
Royal and Professor William Thomson, who showed that, owing to the
position of the tidal wave, the moon is drawn not exactly in the direction
of the earth’s centre of gravity, but a little to the east of that centre, and
that in consequence of this she is made to recede from the earth. Her
orbit is enlarged, and her angular motion diminished. This argument
does not, in Mr. Croll’s opinion, affect his view. The conditions described
by Professor Thomson and the Astronomer Royal do not in the least
degree prevent the consumption of the vis viva of the earth’s motion round
the common centre of gravity, although to a certain extent, at least, it must
prevent this consumption from diminishing the moon’s distance, and in-
creasing her angular motion. But as this consumption of vis viva will go
on through indefinite ages, if the present order of things remains unchanged,
the earth and the moon must therefore ultimately come together.

The Dynamical Theory of Electricity. — Mr. Charles Brooke has addressed
a letter to the Editor of the Philosophical Magazine, alleging that he sees
more reason than ever for believing in the dynamical theory. He gives the
following fact, as strongly confirmatory of the dynamical doctrine. It has
long been known that if a bar of antimony and one of bismuth be con-
nected, and a current be transmitted from antimony to bismuth, heat will
be developed at the point of junction ; and, on the contrary, if the current
pass from bismuth to antimony, cold will be produced. Now it has occurred
to Mr. Brooke, that if in the former, as in all cases where heat is developed
in the passage of a current u a portion of electric potential is converted into
thermic potential, or heat,” there ought in the latter case to be an inductive

SCIENTIFIC SUMMARY.

113

I

conversion of thermic into electric potential ; and if so, there should he a
loss of current in the first instance, and again in the second. And such,
says Mr. Brooke, u appears to he the fact.” u On duly balancing the thermo-
element above mentioned in a Wheatstone’s bridge, the deflection of the
needle followed the direction of the current, and the anticipated loss or gain
of current was fully realized.”

Submarine Photography. — M. Bazin illuminates the bottom of the sea by
means of electric light, for the purpose of discovering the position of
sunken vessels, &c. His photographic studio consists of a strong iron box,
braced transversely, and admitting the light through lens-shaped water-
tight windows ; and he can remain in it without inconvenience for about
ten minutes. He has, it is said, produced sharp and well-defined photo-
graphs, suited to render easy the recovery of objects 'sunk to considerable
depths, and has already worked at depths approaching to 300 feet. — Builder.

On the Halo o/,22§°. — Professor Miller read a paper on this subject before
the Cambridge Philosophical Society. He commenced by a slight sketch of
the difficulties which had been experienced in accounting for the pheno-
menon of haloes, especially in those of 46°. After mentioning some experi-
ments by himself and Mr. Bravais, which showed that the larger halo was
best explained by supposing refraction to take place through the terminal
and one of the lateral faces of the hexagonal prisms of the ice crystal,
Professor Muller described the results of examining a halo radius of 22^-°,
which had been seen in Russia to be formed on the ground ; this, and a
similar halo seen (together with that of 46°) by Professor Ritz during a
(i tourmente ” in the Kandergrund, proved the present theory, that haloes
were caused by the refraction of the sun's rays through ice crystals, to be
right. He also gave an account of some experiments which, during the past
summer, he had made at Rosenlain, at a height of 4,400 feet, with a polari-
scope, which showed that the light of a halo was such as is polarized by
refraction.

The Physics of a Meteorite. — In a recent note in the Proceedings of the
Royal Society, the Rev. Samuel Haughton, of Trinity College, Dublin, gives
a very graphic account of the fall of an aerolite. The fire-ball was seen by
two peasants, who have given the following written statement of their ob-
servations ; and since the facts described by these ignorant men correspond
exactly with the facts theoretically believed to present themselves, we think
the description of the highest interest. It is headed, The Statement of
Eye-witnesses, and runs as follows: “I, John Johnson, of the parish
of Clonoulty near Cashel, County Tipperary, was walking across my potato-
garden at the back of my house, in company with Michael Ealvy and William
Furlong, on August 12, 1865, at 7 p.m. when I heard a clap, like the shot
out of a cannon, very quick and not like thunder ; this was followed by a
buzzing noise which continued for about a quarter of an hour, when it came
over our heads, and looking up, we saw an object falling down in a slanting
direction ; we were frightened at the speed, which was so great that we
could scarcely notice it ; but after it fell we proceeded to look for it, and
found it at a distance of forty yards, half-buried in the ground, where it had
struck the top of a potato-drill. We were some time looking for it (a longer
time than that during which we had heard the noise.) On taking up the

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POPULAR SCIENCE REVIEW.

stone we found it warm (milk warm) but not enough to be inconvenient.
The next day it was given up to Lord Hawarden.”

How to equalise the temperature of Rooms. — The late Mr. Appold, whose
house was always one of the London curiosities from the circumstance that
it was ventilated throughout by means of steam apparatus, invented a most
ingenious automatic instrument for equalising and maintaining a fixed tem-
perature of a room. The apparatus has been presented by his widow to the
Royal Society, and was fully described at a recent meeting by Mr. Gassiot.
The instrument consists of a glass tube having bulbs at each end. The tube
is filled, as also about half of each bulb, with mercury, the lower bulb con-
taining ether to the depth of half an inch, which floats on the mercury. The
tube is secured to a plate of boxwood, and supported on knife-edges, on
which it turns freely. At the end of the plate underneath the highest bulb,
is a lever, to which a string is attached. This string is earned, by means
of bell-cranks, to the supply- valve of a gas-stove or the damper of a furnace.

The instrument acts' in the following manner : Supposing the stove to be
lighted and to have raised the temperature more than is required, the heat
will convert a portion of the ether in the lower bulb into vapour. The
expansion of this vapour drives a quantity of the mercury out of the bulb
underneath it through the tube into the upper bulb. Thi end to which
the mercury has been driven being thus rendered the heaviest falls, and
motion being communicated by the lever to the string, this closes the
supply-valve or damper of the stove or furnace. Of course, if this should
be carried beyond the required extent, the reverse action will take place.

ZOOLOGY AND COMPARATIVE ANATOMY.

Artificial Birds' Nests. — The societies formed for the protection of insecti-
vorous birds in Switzerland, are now setting up artificial nests. One of the
members of a society of this description, who lives in Vevey, having observed
that many species of the kind mentioned select for nests the holes they find
in the branches of rotten trees, and that they consequently do not find it
easy to settle in orchards, where all the trees are in good condition, began,
twenty-five years ago, to set up rotten trunks in his grounds $ and since then
he has had no need to trouble himself in the least about clearing away
caterpillars, that care being entirely left to the birds, who perform their
duty admirably. His neighbours, on the contrary, who have not had this
foresight, have had their orchards laid waste by insects. The Yverdun So-
ciety have gone the length of placing artificial nests even in the public
walks and communal forests, on the borders of the lawns, &c. All those
nests are now inhabited by hedge-sparrows, redstarts, creepers, aud tomtits,
all which may be found in Switzerland as high up as the perpetual snow-
line. The same practice has found its way into Germany.

The Darwinian Theory and the Heliconidce. — Mr Wallace brought before
the British Association the following facts confirmatory of the Darwinian
theory relating to the Heliconidae, one of the family of Lepidiptera. The
Heliconidae, a group of butterflies with a powerful odour, such as to cause

SCIENTIFIC SUMMARY.

115

birds to avoid eating them, were simulated by the females of another group
which had no smell, and might otherwise fall ready victims to birds. By
their great resemblance to the obnoxious butterflies, the scentless females
were enabled to escape pursuit and deposit their eggs. In different regions
there were different species, thus imitating and being imitated. This case
is a crucial test of the truth of the Darwinian doctrine. The females least
like the Heliconidse had always been more subject to destruction, and con-
sequently, by the process of natural selection, the present state of very close
resemblance had resulted.

Specific Relations of the Pig. — M. Sauson asserts that the domestic pig is
not descended from the wild boar j the pig having only five lumbor vertebrae,
whilst the boar has six.

The White Ant. — The Rev. T. Barry of St. Jude's, Randwick, asserts that
the only timber that can effectually resist the white ant is the Jarrah, or
Western Australian mahogany • which is never eaten nor never decays in
the ground.

The Dog , the Ara , and the Frog. — These animals, according to one of our
contemporaries, have disappeared from Martinique and Gaudeloupe, since the
French occupation.

A Rare Sponge. — The British Museum has lately received a series of
specimens of the beautiful sponge called Venus’s flower-basket. — ( Euplectella
speciosuni).

Echinus Lividus.—Pv. Alcock, in a paper read before the Literary and
Philosophical Society of Manchester, described particularly the mechanism
of the teeth and jaws of this animal. He showed, by a dissection of the
parts, that the statement made both by Professor Owen and Professor
Rymer Jones, that the striated surfaces of the jaws are used to comminute
the food is incorrect, for the whole of these surfaces is occupied by muscle,
and is altogether outside the pharynx, through which the food passes. The
specimens examined by Dr. Alcock were from Roundstone Bay.

An Acarus in the Pigeon. — In the last number of the Microscopical Jour-
nal, Mr. Charles Robertson, Demonstrator of Anatomy at Oxford, describes
a hitherto unknown species of acarus, which he found when dissecting a
pigeon. He states that the specimens found by him are small, oval, white,
maggot-like animals, distinctly visible to the naked eye, and are found
chiefly amongst the connective-tissue of the skin, the large veins near the
heart, and on the surface of the pericardium. When few are found, they
generally adhere closely to the surface of the pericardium, and to the large
veins near the heart j if the veins have been previously injected with size
and vermilion, the white transparent acari are seen very distinctly on their
red delicate walls. All the examples which Mr. Robertson examined
were very transparent without any trace of well-defined digestive or
generative organs, even when examined with the highest powers. The
body does not generally present any trace of constrictions, but in a few
examples one or two faint lines were observed, giving the body a seg-
mented appearance, but this may be caused by a mere folding of the soft
cuticle. On the anterior and inferior surface of the body a ridge extends
inwards and downwards from the base of the anterior pair of legs, and unites
with a median single backward ridge. A similar ridge runs in the same
YOL. YI. — NO. XXII* K.

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POPULAR SCIENCE REVIEW.

direction from tlie base of tbe second pair of legs ; but instead of meeting,
as in tbe first pair in tbe median line, are united by a transverse ridge, and
a similar ridge is continued backwards from tbe points where this line joins
those from tbe limbs. This arrangement reminds one of tbe bead of tbe
larva of hexapod insect. No trace of palpi, mandibles, or suckers were
found. Short jointed legs were found in all the specimens examined.
From the above description it will be seen that this acarus agrees with
sarcoptes for having a considerable interval between tbe second and third
pairs of legs, and tbe absence of a furrow between them.

Hearing the Tcenia echinococcus. — We believe tbe Taenia echinococcus has
not hitherto been successfully reared in this country as a matter of experi-
ment. It is therefore satisfactory to learn from a paper presented to the
Royal Society by Mr. Edward Nettleship, that this gentlemen has culti-
vated the echinococcus in the common dog. The following is a brief state-
ment of the experiment On March 28, 1866, the liver and lungs of a
sheep were obtained from Clare Market ; they contained numerous echino-
coccus hydatids ; in some the outer cyst was partly calcified, but all the
hydatids contained clear fluid, and great numbers of scoloces attached to
the endocyst within two hours of the death of the sheep to which the organs
belonged. Two or three of the smaller hydatids were given to a young
dog about six months old — the hydatid being previously punctured — and
the collapsed cyst administered. The dog was then made to drink the
fluid of the cyst in which some echinococci were floating. On May 15 (the
forty-seventh day after the first feeding), the animal was killed, and his in-
testines were examined. In the first ten inches of bowel below the pylorus
there were no taeniae y at that distance a single taenia echinococcus ap-
peared, moving actively ; for the next two or three inches there were none,
but at fourteen inches below the pylorus several more appeared, and im-
mediately after this they became so numerous as to present almost the
appearance of distended lacteals : this continued for about a foot in extent,
and then they gradually became less numerous, and ceased at about three
feet from the pyloric orifice.

The Secreting Organs of Hemiptera. — Mr. Blanchard presented, accom-
panied by an analysis, a memoir of M. Jules Kiinkel, upon the organs of
secretion of the Hemiptera. The author has, in the first place, thoroughly
studied the salivary glands of these insects, a subject on which our know-
ledge is still very imperfect. He then extended his investigations to the
organs which produce the sickening odour of bugs. The gland which ex-
hales this odorous matter is, as we are aware, situated on the ventral or
thoracic front of these animals, at the level of the two anterior legs ; but
the nymphse and the larva are endowed with the same odour, though they
do not possess the secreting gland. M. Kiinkel has discovered that this
organ is replaced in the larvae by two dorsal pouches. When the insect
undergoes its last metarmophosis, these two pouches become atrophied,
while the ventral pouch, which is completely independent of it, becomes
developed. It is easy to comprehend the purpose of nature in this substi-
tution. The larva not having any wings, makes very good use of the two
pouches which are on its back, in the most favourable situation, for driving
away its enemies ; but if these two pouches existed in the same situation on

SCIENTIFIC SUMMARY.

117

the perfect insect; they would be concealed by the wings, and the diffusion
of the odour could not occur.

On the Development of Small Acari in Potatoes. — M. Guerin de Menne-
yille exhibited at a late meeting of the French Academy some specimens
of potatoes covered with acari, but appearing to be perfectly sound. M.
Guerin Menneville remarked that the late two months of wet weather had
produced myriads of acari, known as Tyroglyphus feculce, on the Australian
and other varieties of potato growing on the Imperial farm at Vincennes.
It seems at present uncertain whether this immense crop of acari is the
consequence of the disease in the potato, or the more or less proximate
cause of a change in the tubercle, which will eventually manifest itself.

Beproduction of the Limbs in the Newt. — M. Philippeaux has been per-
forming some experiments with the view of ascertaining whether the limbs
of newts, if completely extirpated, would be regenerated. He found in
numerous instances that when he extirpated the scapula, there was not
the slightest sign of regeneration. On the contrary, when M. Philippeaux
amputated the limb, leaving the basilar portion, it was entirely reproduced,
with all its osseous portions. Experiments of the same nature on fishes
have had a similar result, and M. Philippeaux deduces as a general fact, at
least amongst the vertebrata, that no organ will grow again unless a portion
remains in its place.

On the Structure of the Cornea in Peptiles. — Dr. Lightbody, taking the
tortoise as a type, gives the following account of the structure of the cornea
of the tortoise. It is between that of mammals and fish 3 the lamellae are
thin and well marked, the corpuscles small and few, but pretty regularly
scattered through the whole thickness. The bundles are very broad, and
have almost lost their individuality, blending with their neighbours by their
margins. They are also arranged, as in birds, at right angles to those that
occur immediately above and below them. The corpuscles are fusiform,
and are arranged principally in two directions, one at right angles to the
other. The sensor nerves are very large and strong, with the cells well
marked and pretty numerous. — Vide Journal of Anat. Phys., No. 1.

The Nerves in Insects. — In the last number of the Microscopical Journal
Dr. Moxon describes the arrangement of the nervous system in the larva of
a species of water-gnat. He opposes Dr. Lionel Beale’s views in the
strongest terms, alleging that the nerves by no means end in delicate reticu-
lations, but, as M. Kuhne asserts, end in distinct solid cones or masses. The
nervous fibres, he states, end in the nuclei on the surface of the sarcolemma.
It seems to us, however, that an important objection may be raised to Dr.
Moxon’s views in the fact which he himself adduces, viz. that the larvae in
which he saw this arrangement of the nuclei most distinctly were those
which had been reduced to what he calls a dropsical condition by forty-eight
hours’ confinement in airless water. Dr. Beale’s observations have shown us
that, in order to look for the terminations of the nerve fibres, we must take
the larva and prepare specimens from it at the moment of its death, and
examine them without delay. Dr. Beale did this at the time of the Croonian
lecture to the Itoyal Society, and he then demonstrated satisfactorily that
the nerves do not end, so to speak, but form numerous extremely delicate
fibres^ which are arranged in a complete network.

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Action of Electricity on Noctiluca. — Some very curious experiments, illus-
trative of the action of electricity on this curious infusorian, have recently
been made by MM. Robin and Legros. These authorities deny that the
phosphorescent powers are confined to any particular part of the creature's
body, and they further allege that when a current of electricity is passed
into a vessel of water containing noctilucae, all those specimens which lie
between the poles of the battery are in a state of brilliant phosphorescence ;
and, further, this condition is increased or diminished according as the circuit
is complete or arrested.

The Liguatulce of Serpents. — M. Jacquart has published a memoir, accom-
panied by illustrations, on the above subject. It is said that he has demon-
strated the presence of a subcesophagial ganglion, but that he has been
unable to find a cerebriferous ganglion. M. Jacquart states that the lame
of Linguatulse are just like those of the Lemeae.

Development of the Bothriocephalus latus. — Herr Knock, from experiments
made on various animals, arrives at the conclusion that the embryos of the
Bothriocephalns latus, introduced directly into the intestinal canal of mam-
mals, do not make any movements in the organs of these animals. This
peculiarity causes them to differ from the embryos of tsenias. They also
pass through all the phases of their development, attaining the scolex stage,
and afterwards to their sexual development, without going through the inter-
mediate state of cysticersis. Herr Knock’s experiments establish defi-
nitively that the embryos of Bothriocephalus latus become developed in the
intestinal canal only, at all stages of their existence.

119

RECENT DISCOVERIES IN INSECT EMBRYOGENY.

By HENRY FRIPP, M.D,

Lecturer on Physiology in the Bristol Medical School.

Nam quodcunque suis mutatum finibus exit
Oontinuo boc mors est illius quod fuit ante.

For what from its own confines changed doth pass
Is straight the death of what before it was.

THE audacious simplicity of Topsy, who, unconscious of
parentage, promptly seized upon the on]y plausible expla-
nation of her existence that presented itself, has excited hearty
laughter from many a reader of “ Uncle Tom.” But, though
more experienced in catechisms than rude and ignorant Topsy,
the most accomplished young lady might well have failed to
answer so perplexing a question of origin with equal astuteness
and confidence. In fact, the profound philosophy which lurks
beneath Topsy’s intuition, that not having been uborn” she
must have “growed,” does not appear to have met with due
acknowledgment. No logician could have extricated himself
better from a dilemma forced upon him by false premises. No
zoologist could have more scientifically evaded a question he
was not prepared to solve. No professor of physiology could
have more deftly sheltered himself in the chaos of confused
notions that hangs cloud-like over the boundary lines that sepa-
rate the phenomena of growth from those of reproduction !

Nor is poor Topsy singular in her preference of a ready-made
faith, which shuts out every doubt, over an hypothesis which
might engender uncomfortable suspicions of ignorance. The
world in general does not willingly unsettle itself in matters of
fact and opinion, or show itself anxious to reopen questions
assumed to have been definite^ settled, though this seeming
stability of fact and opinion may be rather due to the exhaustion
of disputants, and the repose which follows temporary conces-
sions, or perhaps to momentary indifference and disinclination
to force an argument to its logical conclusion, for which a slow
moving public opinion may not be prepared.

And yet nothing is more certain than that, during the same
YOL. VI. NO. XXIII. L

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or some future period, every fact and opinion of present or past
times will again be called in question, rediscussed, and dealt with
according to the knowledge and fashion of the day ; to meet,
perhaps, the fate that it escaped before of being criticised, anni-
hilated, and cast into the limbo of past erroneous beliefs, or
perhaps to come forth re-certificated and raised in significance as
a golden truth, which has passed unscathed through the trial by
fire, and shines the brighter for the friction it has undergone.

This re-sifting of fact and recoil of opinion, is most active
when a scientific dogma, established on a scarcely secure footing,
is suddenly brought into collision with unexpected and conflict-
ing testimony : some discovery, for instance, which is seemingly
at variance with accepted belief, or which necessitates a new in-
terpretation of old theory. And such is the actual condition, at
this present moment, of that branch of physiological science
which relates to embryogeny, and more especially to the structure
and properties of u ova.” We purpose, in this article, to make
our readers acquainted with the facts ascertained by recent
labours of zoologists, who have given us an account of their re-
searches. The interpretation of the phenomena to be described
would lead us beyond our present limits, as it involves a com-
plete review of the doctrines of embryology. But a brief indi-
cation of the probable bearing of these discoveries on the
general doctrine of genesis may, perhaps, prove interesting to
the general reader.

The facts, to which we now direct attention, have been inves-
tigated by several foreign naturalists during the last few years,
and will be related in order of their discovery.

1. Professor Wagner, of Casan, found under the bark of a
dead ash branch a grub, which proved to be the larva of an in-
sect belonging to the family Cecidomyia. His attention was
specially arrested by observing that this grub contained within
its own body a number of similar grubs of different size and
in different stages of development. He watched their growth,
from the time of their first appearance as a small organised body
in the midst of the fatty tissue of the parent, up to the period
of their complete larval organisation. The presence of larva
inside the body of another did not at first surprise him, as it is
a well-known occurrence in the history of certain insects, whose
eggs and larva have been found inside caterpillars of a different
species, which have been selected as a temporary home.

But the larva found and examined by Wagner, contained an
internal brood of its own species , which was developed from a
germ mass belonging to itself, and not from eggs deposited by
an enemy,* though in both cases the unfortunate parent is de-

* As in the case of the ichneumon fly, which deposits its eggs in the
caterpillar of the Pieris ; for a good recount of which curious history the

RECENT DISCOVERIES IN INSECT EMBRYOGENY.

121

voured by the cannibal it has sheltered or procreated. The case,
therefore, is one of true larval propagation, or, as it it is usually
termed, u agamic reproduction.” The organic matter which
produces the brood increases as the larvae develop, and the
membrane in which it is enclosed serves ultimately as an invest-
ment, a “ cocoon” for each young embryo before it is disengaged
and thrown into the general cavity of the body.

This reproduction of larval broods continued from August till
May, when the last set of larvae acquired sexually distinct
characters, after passing through the usual metamorphosis, and
becoming mature insects. We had occasion, in a recent num-
ber, to describe the larvation of the aphis, and it seems here
worthy of remark, that the time of year at which viviparous lar-
vation occurs in the aphis, is exactly the contrary of that during
which the propagation of the recently discovered Cecidomyia
larvae goes on. This fact appears to militate against the hypo-
thesis that the functional activity of the reproductive organ
depends on the influence of external temperature, but, on the
contrary, favours the assumption that it depends rather on the
supply of food, the aphis obtaining its nourishment from the
summer juices of plants, whilst the winter larva of the Cecido-
myia feeds on aliment prepared and deposited under the young
bark after the sap changes of the warm season.

But this phase of reproduction proved to be transitory ; for,
as summer advanced, the larva became a pupa, in which sexu-
ally distinct forms were already visible, and, in the course of four
days, perfect male and female insects appeared. The insect
proved to be dipterous. The male, having an expansion of wing
equal to that of the female, but a comparatively much slighter
body, possesses considerable power of flight. The female is, as
usual, a larger-bodied insect, and produces five remarkably large
eggs, which fill the whole abdomen, and contain a yolk-mass,
from which the fatty tissue of the new larva is derived. The
successive larval broods are, in turn, nourished at the expense
of this fatty substance.

The cycle of genetic phenomena is the same, therefore, as in
other creatures in whom “ alternate generations” are observed.
The insect egg has a smooth shell, and is furnished with a fun-
nel-shaped open-mouthed micropyle. The first larva developed
from this egg contains fatty tissue from which the subsequent
broods spring, according to Wagner, who (at the time of
his published memoir), affirmed that no special reproductive
organ existed. This view of the origiu of the larval progeny
coincides, therefore, with Wagner’s account of the histologic
relations of the germ elements. He describes the embryonal

reader is referred to an interesting chapter in Dr. Lawson’s felicitous trans-
lation of Quatrefages’ work on metamorphosis (page 74 et seq.).

L 2

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development as commencing in the fatty tissue of the first larva,
from which tissue small portions are separated. These, at first
grouped together, become afterwards detached in single por-
tions ; their fatty contents become granular ; and from these
vitelline cells and a germ-cell are formed, which go through
rapid development. The Professor’s observations led him fur-
ther to the conclusion that the fatty tissue of the larva is itself
a residue of the original yolk of the egg of the summer insect,
and is therefore endowed with formative powers and a speciality
of function, in virtue of which germs are produced, which un-
dergo rapid transformation, and thus play the part of pseudova,
as observed in other insects. If, however, this fatty tissue be
an actual residue of vitelline matter, it is obviously misnamed.

2. Dr. Meinert, of Copenhagen, was the next to discover the
Cecedomyia. larva (under the back of a beech tree), and to watch
the larval propagation. After following its final metamorphosis
into an insect, he was enabled to describe and name it, and he de-
signates it Miastor Metraloas. He also assents to Wagner’s
opinion respecting the origin of the larval germ from the fatty
tissue, and agrees in considering this tissue as part of the
original formative material derived from the insect egg.

3. Professor Pagenstecher, of Heidelberg, next took up the
investigation. This observer met with similar but smaller larvae
(belonging to another species) in the musty refuse of beet-root
that had been used in a sugar manufactory. This refuse matter
(after extraction of sugar), which was in a state of decompo-
sition, contained abundance of other insect life (larvae of Cole-
optera, Myriopoda, Anguillulae, Podura, &c.), and was sent to
him for examination, because cattle fed with it became diseased.

According to this observer, the fatty tissue has no direct rela-
tion to the germs of the larval broods. These appeared to be, and
are spoken of by him as true “ ova.” The smallest observed
were y^-th inch in length, increasing gradually to JFth inch.
He explains the great increase of bulk which the ova gain
daring development as the result of ordinary nutritive imbibi-
tion, and not of any absorption of the fatty tissue, which, how-
ever, disappears gradually, as the changes of development go on.
The “ ova ” (or germs) were found in their earliest stage chiefly in
the neighbourhood of the posterior segments of the body in the
subcutaneous cellular layer. As they grew larger, they moved
forward, and were lodged in the free spaces between the viscera.
The ova at this time consist of a spheroid mass, whose outer
circle is formed by a layer of clear globules, within which is an
inner mass, composed of granular particles, interspersed with
vacuoles. There is no organic union with the fatty tissue, the
ova lying free in the general cavity (or visceral interspaces).
The embryonal masses described by Wagner have, says Pagen-

RECENT DISCOVERIES IN INSECT EMBRYOGENY.

1*23

stecher, a totally different aspect from these germs or ova. And
the latter observer conjectures, that their origin might be traced
back to one or all of three distinct histologic sources noticed by
him : — 1st, to cells embedded in a tine granular mass, situated
around the intestine in the last larval segment ; 2nd, to cells
appearing very prominent immediately under the integument
which unites the two last segments of the body ; and, 3rd, to
the subcuticular layer of cells before mentioned. Pagenstecher
was unable (from the dying off of his larvae) to carry on his
researches, so as to discover a special reproductive organ.

His account of the further development of these ova is as
follows. By a process of segmentation, a vitelline mass is formed
under its enveloping vitelline membrane, during which process
the outer sphere of clear globules disappears. Then an embryo-
nal cell-layer (including a number of oil-drops) separates itself
from the vitelline mass. These two separate parts increase ra-
pidly, and with equal volume at first, but as the development
proceeds, the embryonal layer gradually overlaps the yolk-mass
towards that end which becomes the head of the embryo. In
larvae prematurely taken out of their envelopes, the residual
yolk-mass is found pushed back to the posterior dorsal region,
and is easily recognised. It might, therefore, be supposed to
become transformed into fatty tissue, and the subsequent larval
propagation thus brought into a certain genetic connection with
the primal evolution of this fatty, or rather formative, material,
derived from the original substance of the true egg. The idea of
a true genetic descent is, by this explanation, still kept in view.
As development proceeds, the parent larva is gradually filled and
swelled out in form by the increase of size of the progeny within.
Pagenstecher observed that the young broods undergo at least
one moult during their growth. Each embryo now shows con-
tractile and extensile movements of its .own, and having broken
through its egg-coverings, moves freely about in the cavity of
the parent body. The parent larva then secretes from the
inner surface of its skin (or subcuticular lining-cell mem-
brane), a kind of second inner skin, which is, however, incom-
plete at the extremities. With these two skins it still lives for
a time, making movements as of extrication, which sometimes
cause the outer skin to give way. On ceasing to live, the
parent becomes a sort of pupa covering, or substitute for it,
to the brood within, which voraciously devours the maternal
viscera. Pagenstecher found in his beetroot refuse many empty
perforated sacs, the remains of the parents from which the
young had escaped.

This observer thus sums up his record : — From some part of
the body, not yet determined, ovales are detached, which fall
free in the larval body, and are transformed into ova by a

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normal process of development. Each ovum produces an embryo
without previous fertilisation. The parent larva undergoes no
metamorphosis, and never becomes a perfect insect. It may,
however, transform itself into an inactive nymph, enclosing the
young brood when completely grown. The evolution and growth
of the ovum and its embiyo goes on at first at the expense of
the parent larva’s circulating fluid, afterwards by absorption
of the nutritive matter previously amassed in the fatty tissue.
Finally, when the embryos are liberated from their egg-cover-
ings, they feed on the viscera of the dead parent. The genera-
tion so produced, reproduces in its turn other generations. Pa-
genstecher concludes, that this form of non-sexual reproduction
is similar to that of the aphis, and that a germ-producing organ
will be discovered by further observation.

4. In the month of March, 1865, M; Ganine announced, in
a paper read before the Academy of St. Petersburg, that he
had found in the worm-eaten planks of buildings, and in worm-
eaten pasteboard, wood, and in other places, larvae similar ta
those examined by Wagner and Pagenstecher, which, holding a
middle place between these, differed slightly in appearance, but
which- propagated in the same way. M. Ganine verifies the
surmise of Pagenstecher respecting the existence of a special
reproductive organ. He found that the germs or ovules were not
generated in or by the fatty tissue, but that they proceeded from
small sacs, which he calls ovaries. These organs, two in number,
are! placed symmetrically on either side of the median line, at the
eleventh segment of the body of the young larva, and lodged in
a small recess excavated on the inner edge of the fatty tissue.

Each “ ovary” is formed by a thin transparent sac, of an oval
shape, intimately adherent to the fatty tissue. The sac is filled
with a clear fluid, containing a few granules, and two or three
small cells. As the larva grows its ovaries increase in size also,
and become detached from the surrounding tissue, with which
they remain connected only by two fine filaments. Whilst this
change of size occurs, germs or “ pseud ova ” are developed.
First of all, the granular contents multiply, and form corpuscles
b}T aggregation. Some of these corpuscles are transformed into
cellules, by being grouped together and enclosed in a mem-
branous envelope. These cellules are seen, at first, only on the
side of the ovaiy, projecting as half circles : by degrees they
enlarge, and, amidst the doubly outlined granules which fill
them, a single larger one may be seen which represents the
“ germinal vesicle,” with its nucleus. This disappears at a
later period, or is confounded with other granules. In the
subsequent development each young u pseud ovum ” is covered
with a thick viscid refractive layer; but the development does
not go on contemporaneously in all the cellules, or equally in

EECENT DISCOVERIES IN INSECT EMBRYO GEN Y.

125

the two ovaries. The most mature are collected at the posterior
margin of the ovary, and their detachment occurs at intervals
corresponding with the period of maturity of each “ pseud ovum.”
After quitting, or even whilst within the “ ovary,” the yolk be-
gins to form, first as fine opaque granules, scattered amongst
the primitive cellules at one end (or pole), soon after which fatty
particles with strongly marked outlines appear, and the ovum
acquires an ovoid shape. The further development takes place
after the ovum has left the ovary, and consists simply in an
increase of yolk elements, which gradually fill the whole egg,
and conceal from the observer what is taking place with the
granules and primitive cellules. The ova, when let loose in the
abdominal cavity, collect together at the posterior segments of
the parent body, but, as the embryos grow, they reach by de-
grees the middle and anterior segments. When they have
attained their full development they escape, first, from their
embryonal envelopes, and then rupture the skin of the parent
larva, to enter life upon their own account.

In the fully developed ovum the first changes observed are
the formation, 1st, of a blastodermic layer on the surface of the
yolk, and 2nd, of a layer of viscid matter, which soon gives
place to a sphere composed of a regular layer of small clear
cells. This, also, soon disappears. The form of the ovum has,
meanwhile, undergone a change by the swelling of the ventral
side. The embryo is developed from a clear, finely granulated
mass, seen at the surface of the yolk. As it grows, the yolk
disappears, but a part remains heaped up at the back of the
embryo, and is afterwards transformed into fatty tissue.

Thus all observers agree in representing the yolk of the ori-
ginal insect egg as not wholly expended in the evolution of the
first larva. But Ganine and Pagenstecher oppose the statements
of Wagner and Meinert, that the fatty matter possesses the
formative property attributed to it by them.

5. We now come to the observations of Leuckart, for the
full account of which we refer our readers to the translation by
Mr. Dallas, published in the March number of the Magazine of
Natural History (of the year 1866). The larvae examined by
Leuckart were found under the bark of a dead apple tree, and
belong to the species Oligarces (determined by Meinert). The
origin of the free germs was traced (as by Ganine) to two small
bodies (primitive germ stock), situated immediately under the
skin of the eleventh segment of the larval body, and fixed by
suspensory ligaments to the Malpighian vessels.

These germ masses consist of a number of clear cells, each of
which contains several vesicular nuclei. The cells lie in a
granular protoplasm, the whole being enclosed within a fine
membranous investment (the (i ovarial sac ” of Ganine).

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POPULAR SCIENCE REVIEW.

After a time, these clear cells are found to contain a number
of small cells, derived from the vesicular nuclei. By successive-
development each cell is gradually transformed into a “germ
hall,” which, when detached from the primitive germ mass,
consists of a membranous envelope, lined by an epithelial layer
of cells (corresponding to the sphere of clear cells described and
prepared by Pagenstecher), within which are a number of cells
(the developed vesicular nuclei), themselves containing a fresh set
of vesicular nuclei. Thus, the “ germ stock ” of Leuckart, from
which his “ germ balls ” are derived, corresponds to the “ ovary”
of Granine : the “ germ ball ” corresponds to the “ pseud ovum ” of
Granine, and is found loose in the larval body. In the physio-
logical interpretation of these parts, our authors diverge con-
siderably. Leuckart dissents from the nomenclature of previous
observers, denying that the “germ ball” is an embryonal
portion of the fatty tissue (Wagner, Meinert), or an ovum
(Pagenstecher), or even a “pseud ovum ” (Granine). He affirms
that it is a germ chamber (an ovarian tube, in fact), and that it
gives off a reproductive body (pseud ovum), in accordance wTith
the type of egg formation in insect ovaries generally. The egg
chamber of insects is, however, not, as in the case of these
larvae, free , but fixed, and usually forms the terminal portion of
an ovarian tube. Leuckart maintains, nevertheless, that the
“germ balls” are a true analogue of insect germ chambers, and
compares them, in particular, with the germ chambers of Melo-
phagus, which are so deeply constructed as to be only united by
a thin cord, and therefore almost as independent as the Cecido-
myia germ balls. This opinion is supported by Leuckart’^
account of the morphological changes, as observed by him,
during the further development of the embryo inside the germ
ball or chamber.

As before described, the mature germ ball consists of an enve-
loping cell lined membrane, the interior space being full of cells-
derived from the transformed vesicular nuclei. These secondary
cells contain nuclei also. After a short time each secondary
cell becomes surrounded with granular plasm, which distends-,
the germ ball at one end until it assumes a pyroform shape.
The granular mass at the other end differentiates into a sub-
stance which quickly transforms itself into a distinct mass, filling
up more and more of this interior space, the germ ball becoming
oval in shape. At one end (or, pole), there lies embedded in the
granular plasm a regular nucleus (germ cell), which does not
increase in volume equally with the mass around it. In
Granine’s figures this granular mass is distinctly shown, but
described as the yolk mass of the pseud ovum. Leuckart, how-*
ever, comparing the whole with an insect germ chamber,,
considers the envelope with its cell-lining as corresponding with

RECENT DISCOVERIES IN INSECT EMBRYOGENY.

127

the ovarian chamber, the granular mass, together with its in-
cluded nucleus, as corresponding with the ordinary germinal
vesicle, filling one end of the chamber , and the remaining cells,
together with their surrounding matter, as representing the
formative cells of the yolk filling the other part of the chamber.

In the course of subsequent development the lining cells of
this envelope disappear, and a line, or layer, of granules is found
in their place. The dark, granular mass, with its enclosed
nucleus, is the reproductive body (germ egg, or pseud ovum),
a germinal membrane being formed over the yolk before it fills
the entire chamber. The formative cells of the yolk disappear
also as the bulk of the yolk increases, but three or four cells
remain at one end of the chamber, and these M. Mecznikoff, who
assisted Leuckart in his researches, found to be not vitelline-
cells, but so-called “polar cells,” which were finally traced in
the young embryo as the rudiment of its germ stock. These
polar cells being, therefore, the progeny, by endagimous multi-
plication, of the original cells lining the chamber, may be
supposed to possess the reproductive power, and to be capable of
repeating the procreative process when the larvae containing
them have attained to independent life.

With the other naturalists, Leuckart considers this organic
larval propagation as essentially identical with that of Aphis.
The germ stock of Cecidomyia he regards as an analogue of the
sexual glands, and its filament of connection with the Malpighian
vessels as a rudimentary efferent duct. Their germ stock being a
sexual apparatus (female only?) the germ ball ranks as an ova-
rian chamber, and its contents constitute the reproductive
body (germinal cell and yolk, with residual polar cells which
belong to the new germ stock) a sexual apparatus of the larva.
The viviparous larvation on this plan is not “ gemmiparous,”
but true Parthenogenesis, i.e. the procreation of germs or pseud
ova in an organ of female character, unaccompanied by any
fertilising element. None of our authors appear to have ob-
served anything resembling the combination of germ and sperm
cells, described by Balbiani as existing in the Aphis germ stock.
The description given by the latter is, however, so enigmatical
as to demand further corroboration.

Leuckart objects to the use of the term ovum, though mor-
phologically undistinguishable in the maturely developed germ
chamber, because the larva is an immature animal, and sexless.
The word “ pseud ovum” he admits as meeting the physiological
definition of power possessed by the germ, but remarks that the
“ alternate generation,” in this instance, differs from the usual
form, because the sexual individuals which close the cycle of
reproduction undergo further metamorphosis before they attain
to maturity.

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6. Siebold has also published his views respecting this larval
propagation, but we have not had any opportunity of studying
them. (Kolliker and Siebold’s Zeitschrift.) But in concluding
this historical notice, we must notice the later publications of
X)r. Meinert in M. Schrodte’s Natur-historik Zidschrift , vol. iii.
third series, an abstract of which the author sent to the Annates
des Sciences (number for July 1866). In the first of the two
memoirs, Meinert still maintains that the larval germs are de-
rived from the fatty tissues of the larva. In the second memoir, he
enters more particularly into this disputed point, and discusses
the whole subject of animal embryogeny. The larvse discovered
by Pagenstecher and Leuckart belong, he says, to species differing
from that discovered by Wagner. Having succeeded in this,
as in the other case, in obtaining the perfect insect from the
larval form, he describes and names it Oligarces. He also re-
peats his opinion that the germs or ova from which the larvae
spring stand in direct connection with and relation to the fatty
tissue, maintaining that, in Miastor, the germs remain persist-
ently connected with this substance, whilst in Oligarces, the
germ mass only partially separates from the fatty matter; and
that, neither in the one nor the other, is there, as Leuckart
insists, any proper ovary ; ” for, he observes, the whole mass
of germ stock is broken up into germs, and none of the cellules
supply any true ovarial stroma, nor form egg- membranes, nor
develope into any organs or tissues having analogous functions.

All our authors, however, agree in one point, namely, that the
larva germ is essentially a cell-forming material, and partakes
of the character usually assigned to female sexual organs. The
total absence of any morphological element possessed of a male
or fertilising function, seems likewise agreed upon, or may be, at
least, negatively inferred. The mode of development is also
described by each as essentially an endogenous multiplication of
cells, which become either yolk or germ cells, or polar cells, by
a process of differentiation, which indicates the highest forma-
tive power inherent in reproductive organisms. Even the pro-
toplasm, whether clear or granular, must be viewed as the
production of cells previously active, and this organic matter,
whether in solid or fluid state, is equally endowed with pro-
perties that may be called vital. The self-contained power
of evolution, whereby not merely a tissue or part of a body is
formed, but the whole assemblage of organs and tissues which
constitutes an individual — nay, much more, the future dimor-
phism of yet undeveloped sexual individuals being included in
the effect of this self-contained power of evolution — places the
reproductive process in a different category from the repetitive
process of growth ; and, for this reason, the propagation of larval
germs cannot be classed with “ gemmiparous reproduction.”

RECENT DISCOVERIES IN INSECT EMBRYOGENY.

129

A general doctrine of ovology is propounded by Dr. Meinert
in his second memoir, which is briefly this : — In mammalia, and
most of the invertebrata, the ovum consists of a simple germinal
cell, of which the nucleus is the so-called germinal vesicle.
This germinal cell undergoes segmentation, and is thus multi-
plied by subdivision into minute embryonal cells. A portion of
those not required for the formative development of the embryo
is reserved for the reproductive organs of the new individual,
which contain the respective sperm and germ elements, to be
afterwards developed in future generations. In birds, reptiles,
fishes, &c., the ovum receives, in addition to the germinal cell,
either a number of yolk cells, or a secretion from them constitutes
a yolk. These vitelline cells do not, like the germinal cell, un-
dergo morphologic development, but pass, without any forma-
tive changes, to the nutritive yolh. In almost all insects there
is, besides, the germinal cell, a vitelline secretion. The resi-
dual cells derived from endogenous multiplication of the germi-
nal cell are, in the insect, the essential part of the tissue, which,
by transformation, becomes the fatty substance. Whatever value
may be attached to this scheme of ovology, the physiological dif-
ficulties of genesis remain still unsolved, and the doctrine of
Parthenogenesis remains, as before, a riddle. When Meinert
adds to his anatomical scheme the assumption that the influence
of a male element is not indispensable — not even necessary— to
the development of the germ cell in all those invertebrata cha-
racterised by non-sexual propagation, the ^conclusion may be con-
sidered premature, to say the least. The exceptions to a law
almost universal are neither so absolutely confirmed, nor so
numerous, as to disprove its absolute character. The dimor-
phism of all creatures (male and female), which seems to be inse-
parably connected with the law of genesis, is preserved equally
in the creatures temporarily multiplying by immature genera-
tions. And again, the combination of male and female elements
for the production of a new creature, may not be at once ob-
vious, because the types of reproductive organisation may really
vary more than we are at present aware of. For instance, forms
of hermaphroditism, still more rudimentary than yet observed,
might easily be imagined. We are not, therefore, warranted in
rejecting the widest application of the known genetic law, be-
cause cases occur in which it is masked by the occurrence of
special intermediate phases of life, the further study of which
may completely confirm and rehabilitate the single and absolute
law of genesis.

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POPULAR SCIENCE REVIEW.

EXPLANATION OF PLATE VI.

Fig.

V

V

V
f)

}}

V

1. Hinder segments of a young larva, showing the fatty matter with

“ovary ” or “ germ stock ” imbedded in each lateral mass.

2. Ovary of a larva, 1 mm. long and T7 wide — filament of connection

with Malpighian vessels — cellules.

3. Ovary in which commencement of future pseud-ova appear.

4. Ovary containing seven young pseud-ova.

5. A pseud-ovum free — vitellus forming.

6. Do., almost filled with vitellus, the cells reduced in number, and

(polar cells) congregated in the clear end.

7. A portion of ovary from which nearly half the pseud-ova have

already detached.

Fig. 1 from Wagner — Figs. 2 to 7 from Ganine — Figs. 8 to 16,
Pagenstecher.

8. A larva with large ova, in which the embiyonal development is

proceeding.

9. 10, 11, 12, 13, 14. Progressive stages of development of ovum up

to period of embryonal layer (bourrelet.) The next stages are
seen in Fig. 8.

„ 15. An embryo withdrawn from its envelope before maturity. The

dorsal portion is bulged by the residual vitellus. ■ The eyes, the
armature of spines for locomotion, the adipose mass, the oeso-
phagus and intestinum rectum, with Malpighian vessels, are dis-
tinguishable; also the ventral cord and ganglia with supra-
oesophageal ganglion.

,, 16. A full-sized larva, with five young larvae moving freely in its in-

terior. The anterior and posterior extremities of the parent
larva are retracted and separated from the exterior chitinous
envelope, so that the head of the nymph is seen under the skin
of the head of the parent larva.

N.B. — Fig. 5 is not in direct continuation with Fig. 4. It represents the
later development of one of the u ovules ” in Fig. 4.

Fig. 7 represents the ovary containing ovules in different stages of de-
velopment between that shown in Figs. 4 and 5.

N.B. — The colour is only intended to distinguish the fatty tissues and
Malpighian vessels in the diagram, not as the colour of nature.

BIBLIOGRAPHY.

Wagner in Zeitschrift fiir Wiss. Zool. 1863, page 513.

Meinert Do. Do. 1864 „ 394.

Pagenstecher Do. Do. 1864 „ 400, and in Zeitschrift,

1865, 4th part.

Ganine, in Bulletin de l’Acad. de St. Petersbourg, 1865.

Annales des Sciences, November, 1865, page 259.

Dp. Do., letter from Meinert, July, 1866.

Leuckart in Wiegman’s Archive, 1865, p. 286. (Translated by Mr. Dallas,
in March No., 1866, of Mag. Natural History.)

131

ON THE STRUGGLE FOR EXISTENCE AMONGST
PLANTS.

By J. D. HOOKER, M.D., F.R.S.

THE quaint dictum, u Plants do not grow where they like
best, hut where other plants will let them,” which is credited
to the late eminent horticulturalist, Dean Herbert, of Manches-
ter, expresses a truth not yet half appreciated by botanists. It
is a protest against the prevalent belief, that circumstances
of climate and soil are the omnipotent regulators of the dis-
tribution of vegetables, and that all other considerations are
comparatively powerless. The dean’s crude axiom has lately
found a philosophical exposition and expression, in Mr. Darwin’s
more celebrated doctrine of the ct Struggle for life, and preserva-
tion thereby of the favoured races,” and if to it we add that
great naturalist’s more fruitful discovery, of the necessity for
insect and other foreign agencies in ensuring fertility, and
hence perpetuating the species, we shall find that the powers
of climate and soil are reduced to comparatively very narrow
limits. Before proceeding to show what are the causes that
do materially limit the distribution of species, it may be well
to inquire how far the hard-pressed soil and climate theory
really helps us to a practical understanding of one or two great
questions that fall under our daily observation ; of these, the
following are the most prominent.

That very similar soils and climates, in different geographical
areas, are not inhabited, naturally, either by like species, or like
genera ; — that very different soils and climates will produce
almost equally abundant crops of the same cultivated plants ;
— and that in the same soil and climate, many hundreds, nay,
thousands of species, from other very different soils and. climates,
may be grown, and propagated, for an indefinite number of
successive generations.

Of the first , of these statements, the examples embrace some
of the best known facts in geographical botany ; as, for example,
that the Flora of Europe differs wholl}T from that of temperate
North America, South Africa, Australia, and temperate South
America, and all these from one another. And that neither soil
nor climate is the cause of this difference, is illustrated by the

132

POPULAR SCIENCE REVIEW.

fact, that thousands of acres in each of these countries are co-
vered, year after year, by crops of the same plant, introduced
from one to the other ; and by annually increasing numbers of
trees, shrubs, and herbs, that have either run wild, or are suc-
cessfully cultivated in each and all of them. The third pro-
position follows from the two others, and of this the best example
is afforded by a good garden, wherein, on the same soil and
under identical conditions, we grow, side by side, plants from
very various soils and climates, and ripen their seeds too, pro-
vided only that their fertilization is insured. The Cape gera-
niums, London pride and Lysimachia nummularia in our London
areas, the pendent American cacti in the cottage windows of
Southwark and Lambeth, are even more striking examples of
the comparative indifference of many plants to good or bad
climate and soil ; and what can be more unlike their natural
conditions than those to which ferns are exposed in those in-
valuable contrivances, Ward’s cases, in the heart of the city?
True, the conditions suit them well, and with respect to
humidity, and equability of temperature, are natural to them ;
but, neither is the absolute temperature, nor the constitution,
nor freshness of the air, the same as of the places the ferns are
brought from ; nor is any systematic attempt made to suit the
soil to the species cultivated, for, as Mr. Ward himself well
shows, the arctic saxifrage, the English rose, the tropical palm,
and desert cactus, live side by side in the same box, and under
precisely similar circumstances, and, as it were, in defiance of
their natal conditions.

Let it not be supposed that we at all underrate such power as
soil and climate really possess. In some cases, as those of chalk,
sand, bog, and saline and water plants, soil is very potent ; but
the number of plants actually dependent on these, or other
peculiarities of the soil, is much more limited than is supposed.
Of bond fide water-plants, there are few amongst phsenogams.
Sand plants, as a rule, grow equally well on stiffer soils, but are
there turned out by more sturdy competitors ; and with regard
to the calcareous soils, it is their warmth and dryness that fits
them, to so great an extent, for many plants that are almost con-
fined to them, or are absolutely peculiar to them. So, too, with
regard to temperature, there are limits, as regards heat, cold,
and humidity, that species will not overstep and live ; but, on
the other hand, so much has been done by selection in procuring
hardy races of tender plants, and so much may be done by re-
gulating the distribution of earth-temperature, &c., that we
already grow tropical plants in the open air during a portion of
the year, and eventually may do so for longer periods.

Amongst the most striking examples of apparent indifference
to natural conditions of soil and climate, I would especially

ON THE STRUGGLE FOR EXISTENCE AMONGST PLANTS. 133

adduce two. One is the Salicorma Arabica , a plant never
found in its natural state, except in most saline situations, but
which has flourished for years in the Succulent blouse at Kew,
in a pot full of common soil, to which no salt has ever been
added ; the other is the tea plant, which luxuriates in the hot
humid valleys of Assam, where the thermometer ranges between
70° and 85°, and the atmosphere is so perennially humid,
that watches are said to be destroyed after a few months of
wear ; and it is no less at home in North-Western India, where
the summers are as hot and cloudless as any in the world, and the
winters very cold. I may add, that the tea plant has survived
the intense cold of this last January, at Kew, on the same wall
where many hardy and half-hardy plants have been killed.

It is, further, a great mistake to suppose that the native vegeta-
tion of a country suffers little and very exceptionally by abnormal
seasons. The most conspicuous instance of the contrary that
ever fell under my observation, was the destruction of the
gigantic gum-tree ( Eucalyptus ) forests, in the central districts
of Tasmania, which occurred, if I remember right, about the
year 1837. In 1840 I rode over many square miles of country,
through stupendous forests, in which every tree was, to all ap-
pearance, absolutely lifeless. The district was totally uninha-
bited, consisting of low mountain ranges, 2,000 feet above the
sea, separating marshy tracts interspersed with broad fresh-water
lakes. The trees, much like the great gaunt elms in Kensing-
ton Gardens during winter, but much larger, were in countless
multitudes, 80 to 180 feet high, close-set, and 10 to 20 feet in
girth ; their weird and ghostly aspect being heightened by the
fact of most being charred for a considerable distance up the
trunk, the effects of the native practice of firing the grass in
summer during the kangaroo hunting season ; and by the bark
above, hanging from their trunks in streaming shreds, that
waved dismally in the wind ; for the species was the stringy-
bark gum, that sheds its bark after this fashion. And not only
had the gum-trees suffered, the hardier LepiosjpermuWt (tea-tree
bush), and many others, were killed, some to the ground, and
some altogether; so that though my journey was in spring, and
the weather was delightful, the aspect of the vegetation was
desolate in the extreme.

In such climates as our own, similar devastations are un-
known, and though we know that our island was once covered
with other timber than now clothes it, we have every reason to
suppose that the change was slow, and the effect either of a
gradually altered climate, or of the immigration of trees equally
well or better suited to the conditions of the soil and climate, but
which had not previously had the opportunity of contesting the
; ground with the ruling monarchs of the forest.

134

POPULAE SCIENCE EEVIEW.

Making every allowance, then, for the influence of soil and
climate in checking the multiplication of individuals, we have still
two classes of facts to account for ; the one, that plants which
succeed so well, when cultivated, that we are assured both soil and
•climate are favourable to their propagation, nevertheless become
immediately or soon extinct when the cultivator’s care is with-
drawn ; the other, that plants of one country, when introduced
into another, even with a very different soil and climate, will
overrun it, destroy the native vegetation, and prove themselves
better suited to local circumstances than the aboriginal plants of
the country. In the first case, the reasons are very various,
all of them relating to the conditions of the plant’s existence.
Of these the two most potent are, the absence of fertilising
agents, and the destruction of seeds and seedling plants. In
the present state of our knowledge it is impossible to say which
of these is most fatal in its effect. In the case of our annual
plants, or our cereals, which never run wild, it is the latter
certainly, for they seed freely enough; in the case of many
perennials, shrubs, and trees, it may be the former, as with the
common elm and lime, which rarely or never seed in England,
though the latter is so notably frequented by insects during its
flowering season ; whilst a third cause is to be found in their
seedling plants being smothered by others, of which we have
numerous examples in our common pasture grasses, which are,
perhaps, the most prejudicial in this respect. A most conspicuous
example of this is afforded by the common maple, of which the
seedlings come up early in spring by thousands in the neighbour-
hood of the parent tree, in lawns and plantations, but scarcely
ever survive the smothering effects of the common summer
grasses, as soon as these begin to shoot.

When I visited the cedar grove on Mount Lebanon, in the
autumn of 1860, 1 found thousands of seedling plants, but every
one of them dead ; and so effectual is the annual slaughter of
the yearlings in that grove, that, though the seeds are shed in
millions, and innumerable seedlings annually spring up, there is
not a plant in the grove less than about sixty years old. It
may hence have been sixty years since a cedar there survived the
first year of its existence ; that is to say, has struggled through
its infancy, and reached the age even of childhood !

On the other hand, when once the natural conditions of a
country have been disturbed, the spread and multiplication of
immigrants is so rapid, that it shortly becomes impossible to
discover the limits of the old, indigenous Flora. Take the
English Flora, for example. If we contrast the cultivated counties
with the uncultivated, the difference of their vegetation is so
great, that I have often been compelled to doubt whether many
of the most familiar so-called wild flowers of the cultivated

ON THE STBUGGLE FOE EXISTENCE AMONGST PLANTS. 135

counties are indigenous at all ; nay, more, I have been tempted
to suspect that some of the more variable of them, as some
species of chenopodium and fumitory, may have originated since
cultivation began. In the uncultivated counties, the proportion
of annual plants is exceedingly small, whereas, in the cultivated
counties, annuals are very numerous ; and the further we go from
cultivation, roads, and made-ground, the rarer they become, till
at last, in the uninhabited islets of the west coast of Scotland,
and in its mountainous glens, annuals are extremely rare, and
confined to the immediate vicinity of cottages. Let any one
who doubts this contrast between the Floras of cultivated and
uncultivated regions compare the annuals in such Florae as those
of Suffolk or Essex, the North Riding or Cumberland, with those
of the Isle of Wight and the Isle of Arran. And it is not only
that annuals abound in the cultivated districts, but that so
many are nearly confined to ground that is annually or fre-
quently disturbed. The three commonest of all British plants,
for example, are, perhaps, groundsel, shepherd’s purse, and
Poa annua . I do not remember ever having seen any of these
plants established where the soil was undisturbed, or where,
if undisturbed, they had not been obviously brought by man, or
the lower animals ; and yet I have gathered one of these, the
shepherd’s purse, in various parts of Europe, in Syria, in the
Himalayas, in Australia, New Zealand, and the Falkland Islands.
Were England to be depopulated, I believe that in a very few
years these plants, and a large proportion of our common
annual “ wild flowers,” would become exceedingly rare, or ex-
tinct, such as the Poppies, Fumatories, Trefoils, Fedias, various
species of Speedwell, Anagallis, Cerastiums, Lithospermum,
Polygonum, Mallow, Euphorbia, Thlaspi, Senebiera, Medicago,
Anthemis, Centaurea, Linaria, Lamium, &c., &c.

It is usually said of some of the above named plants, that they
prefer cultivated ground, nitrogenous soil, and so forth; and
this is no doubt true, but that they will flourish where no such
i advantages attend them, a very little observation shows; and
that they do not continue to flourish elsewhere is due mainly
to the fact that, being annuals, their room is taken as soon as
they die, and the next year’s seedling has no chance of success
in the struggle with perennials.

For good instances of this rapid replacement of annuals by
perennials, the new railroad embankments should be examined.
Whence the plants come from, which spring up like magic in the
\ cuttings, many feet below the surface of the soil, is a complete
mystery, and reminds us of the so-called spontaneous generation
of protozoa in newly-made infusions, or in distilled water. In
the south of Scotland in 1840-50, and many parts of the north of
i England, the first plant that made its appearance was Equisetum

VOL. VI. — NO. XXIII. M

136

POPULAR SCIENCE REVIEW.

arvense, which covered the new-formed banks, for miles and
miles, with the most lovely green forest of miniature pines. In
the following year comparatively few of these were to be seen,
and coltsfoot, dandelions, and other biennials, especially Um-
belliferse, with a great number of annuals, presented them-
selves. For many successive years I had no opportunity of
watching the struggle for life on these banks, but when I last
saw them they were clothed with perennial grasses, docks,
plantains, and other perennial rooted plants.

The destruction of native vegetations by introduced is a sub-
ject that has only lately attracted much attention, but it has
already assumed an aspect that has startled the most careless
observer. Some thirty years ago the fecundity of the horse and
European cardoon in the Argentine provinces of South America,
so graphically described by Sir Edmund Head, drew the atten-
tion of naturalists to the fact, that animals and plants did not
necessarily thrive best where found in an indigenous condition ;
and the spread of the common Dutch clover. Trifolium repens ,
in North America, where it follows the footsteps of man through
the pathless forests, has long afforded an equally remarkable
instance of vegetable colonisation. Still more recently, in
South Africa, Australia, and Tasmania, the Scotch thistle, briar
rose, Xanthium, plantains, docks, &c., have all become noxious
weeds ; and this leads me to the last and most curious point to
which I shall allude in this article, viz., that the same annuals
and other weeds, that are held so well in check by the indi-
genous perennial plants of our country, when transplanted to
others, show themselves superior to the perennial vegetation of
the latter. Of this New Zealand famishes the most conspicuous
example, — it was first visited scarcely more than 100 years ago,
and it is not yet fifty since the missionaries first settled in it, and
scarce thirty since it received its earliest colonists. The Islands
contain about 1,000 species of flowering plants, amongst which no
fewer than 180 European weeds have been recorded as intruding
themselves, and having become thoroughly naturalised ; and
probably double that number will yet be found, as they have
never been systematically collected; but the most curious part
of the history is this, that whereas of indigenous New Zealand
plants scarcely any are annual, no less than half the naturalised
European ones are annual.

Of the effect of these introduced European plants in destroying
the 'native vegetation, I have given examples in an article
that appeared in the Natural History Review (January, 1864),
from which I quote the following : —

In Australia and New Zealand, the noisy train of English
emigration is not more surely doing its work, than the stealthy
tide of English weeds, which are creeping over the surface of

ON THE STKUGrGrLE FOK EXISTENCE AMONGST PLANTS. 137

the waste, cultivated, and virgin soil, in annually increasing
numbers of genera, species and individuals. , Apropos of this
subject, a correspondent (W. T. Locke Travers, Esq., F.L.S.) — -
a most active New Zealand botanist — writing from Canterbury,
says: “ You would be surprised at the rapid spread of European
and other foreign plants in this country. All along the sides of
the main lines of road through the plains, a Polygonum ( avicu -
lare\ called c cow-grass,’ grows most luxuriantly, the roots
sometimes two feet in depth, and the plants spreading over an
area from four to five feet in diameter. The dock ( Rumex
obtusifolius or R. crispus) is to be found in every river-bed,
extending into the valleys of the mountain-rivers, until these
become mere torrents. The sowthistle is spread all over the
country, growing luxuriantly nearly up to 6,000 feet. The
watercress increases in our still rivers to such an extent as to
threaten to choke them altogether ; in fact, in the Avon, a still
deep stream running through Christ Church, the annual cost of
keeping the river free for boat navigation and for purposes of
drainage, exceeds 3001. I have measured stems twelve feet
long and three quarters of an inch in diameter. In some of the
mountain districts, where the soil is loose, the white clover is
completely displacing the native grasses, forming a close sward.
Foreign trees are also very luxuriant in growth. The gum-trees
of Australia, the poplars and willows, particularly, grow most
rapidly. In fact, the young native vegetation appears to shrink
from competition with these more vigorous intruders.”

Dr. Haast, F.L.S., the eminent explorer and geologist, also
writes to me as follows : —

“ The native (Maori) saying is, c as the white man’s rat has
driven away the native rat, as the European fly drives away our
own, and the clover kills our fern, so will the Maoris disappear
before the white man himself.’ It is wonderful to behold the
botanical and zoological changes which have taken place since
first Captain Cook set foot in New Zealand. Some pigs, which
he and other navigators left with the natives, have increased and
run wild in such a way that it is impossible to destroy them.
There are large tracts of country where they reign supreme.
The soil looks as if ploughed by their burrowing. Some station
holders of 100,000 acres have had to make contracts for killing
them at 6d. per tail, and as many as 22,000 on a single run
have been killed by adventurous parties without any diminution
being discernible. Not only are they obnoxious by occupying
the ground which the sheep farmer needs for his flocks, but
they assiduously follow the ewes wThen lambing, and devour the
poor lambs as soon as they make their appearance. They do
not exist on the western side of the Alps, and only on the lower
grounds on the eastern side where snow seldom falls, so that

138

POPULAR SCIENCE REVIEW.

the explorer has not the advantage of profiting by their exist-
ence, where food is scarcest. The boars are sometimes very
large, covered with long black bristles, and have enormous
tusks, resembling closely the wild boar of the Ardennes, and
they are equally savage and courageous.

“Another interesting fact, is the appearance of the Norwegian
rat. It has thoroughly extirpated the native rat, and is to be
found everywhere, even in the very heart of the Alps, growing to a
very large size. The European mouse follows it closely, and, what
is more surprising, where it makes its appearance, it drives, in a
great degree, the Norway rat away. Amongst other quadrupeds,
cattle, dogs, and cats are found in a wild state, but not abundantly.

“The European house-fly is another importation. When it
arrives, it repels the blue-bottle of New Zealand, which seems
to shun its company. But the spread of the European insect
goes on very slowly, so that settlers, knowing its utility, have
carried it in boxes and bottles to their new inland stations.”

But the most remarkable fact of all has been communicated
to me since the above was printed, viz., that the little white
clover, and other herbs, are actually strangling and killing out-
right the New Zealand flax ( Phormium tenax), a plant of the
coarsest, hardest, and toughest description, that forms huge
matt ed patches of woody rhizomes, which send up tufts of sword-like
leaves, six to ten feet high, and inconceivably strong in texture
and fibre. I know of no English plant to which the New Zea-
land flax can be likened, so as to give any idea of its robust consti-
stitution and habit, to those who do not know it ; in some
respects the great matted tussocks of Carex paniculata approach
it. It is difficult enough to imagine the possibility of white
clover invading our bogs, and smothering the tussocks of this
Carex, but this would be child’s play in comparison with the
resistance the Phormium would seem to offer.

The causes of this prepotency of the European weeds are pro-
bably many and complicated ; one very powerful one is the
nature of the New Zealand climate, which favours the duration
of life in individuals, and hence gives both perennials and
annuals a lengthened growing season, and, in the case of some,
more than one seed crop in the year. This is seen in the
tendency of mignionette and annual stocks to become biennial
and even perennial, in the indigenous form of Cardamine hir-
suta being perennial, and in the fact that many weeds that seed
but once with us, seed during a greater part of the year in New
Zealand. Another cause must be sought in the fact, that more
of their seeds escape the ravages of birds and insects in New
Zealand than in England; the granivorous birds and insects
that follow cultivation not having been transported to the
Antipodes with the weeds, or, at least, not in proportionate
numbers.

ON THE STRUGGLE FOR EXISTENCE AMONGST PLANTS. 139

Still the fact remains as yet unaccounted for, that annual
weeds, which, except for the' interference of man, would with
us have no chance in the struggle with perennials, in New Zea-
land have spread in inconceivable quantities into the wildest
glens, long before either white men or even their cattle and flocks
penetrate to their recesses. Such is the testimony of Drs.
Haast and Hector, and Mr. Travers, the original explorers of
large areas of different parts of the almost uninhabited middle
island, and who have sent to me, as native plants, from hitherto
unvisited tracts, British weeds, that were not found in the island
by the careful botanists (Banks, Solander, Forster, and Sparr-
mann) who accompanied Captain Cook in his voyages; and
which were not found by the earlier missionaries, but which of
late years have abounded on the low lands near every settlement.

This subject of the comparative great vis-vitae of European
plants, as compared with those of other countries, involves
problems of the highest interest in botanical science, and the
subject is as novel as it is interesting ; it is quite a virgin one,
and requires the calmest and most unprejudiced judgment to
treat it well. It cannot be doubted that the progress of civili-
sation in Europe and Asia has, whilst it has led to the incessant
harassing of the soil, led also to the abundant development of
a class of plants, annual, biennial, and perennial, which increase
more rapidly and obtain a greater development when ' trans-
planted to the Southern hemisphere, than they have hitherto
done in the Northern, and that, in this respect, they contrast
strikingly with the behaviour of plants of the Southern hemi-
sphere when transplanted to the Northern ; and hitherto no con-
siderations of climate, soil, or circumstance, have sufficed to
explain this phenomenon.

140

HOW TO STUDY METEOKOLOGrY.
Br O. F. CHAMBEKS, F.E.A.S.

THE present paper is designed to meet such remarks as the
following : “ I am rather interested in Meteorology. I have
got plenty of time on my hands. If I knew what to do, and
how to do it, I would try and make myself useful to the cause
of science.” It is believed that the number of persons who de-
vote their energies to the study of Meteorology would be much
increased if there were a clear appreciation in the public mind
of the fact that a moderate amount of labour, directed into
proper channels, would produce results which are as much
useful as curious. I lay stress on the word “ useful.” I wish
strenuously to insist, that Meteorology is not a science of mere
curiosity, but that on its cultivation depend great questions con-
nected with the public health, agriculture, and navigation.

Meteorology may be sufficiently defined as the study of the
weather ; practical Meteorology, as a subdivision in which we
consider what we are to observe, and how we are to observe,
including, of course, the use of instruments. Meteorology differs
from most other sciences cultivated in the present day in this
respect, that although naturally having different branches, the
respective branches can be studied separately and independently,
to a greater or less extent, without incongruity. One man,
for example, may busy himself with the rainfall of a country ;
another with its winds, and so on.

I shall avail myself of this circumstance to divide my re-
marks into sections, not only because that will be, on general
grounds, convenient, but also because it will permit the reader,
intending to become a working observer, to pick out with fa-
cility the particular subject to which he prefers confining his
attention.

■ Kainfall. — On the whole, this may be pronounced the most
important of all meteorological topics. On an excess or a defect
in the rainfall of a place depend a variety of things intimately
associated with the well-being of the community resident there.
Neither is it a trifling matter, that pluviometrical observations
require no experience or scientific training; nothing, in fact,

HOW TO STUDY METEOROLOGY.

141

but that methodical common-sense which every fairly educated
person is presumed to possess.

A rain-gauge is a contrivance for ascertaining how much rain
falls on a particular surface of ground — to what depth it would
accumulate if it neither ran away nor soaked in. With any
cylindrical vessel and a foot-rule, a notion of the quantity of
rain that has fallen can be arrived at, but this involves accidental
errors, owing to evaporation, and to the difficulty of seeing, to a
nicety, how deep the rule has to be plunged into the collected
water. Fig. 1 represents a cheap and convenient gauge, known
as Howard’s. It consists of a metal funnel, the rim of which is
accurately turned to a certain diameter (usually five or six inches)*
The rain, passing through the funnel, is collected in the earth-
enware receiver. The receiver is emptied once in twenty-four
hours, the contents being poured into a graduated glass. The
diameter of the glass is so adjusted* to the diameter of the
funnel, that a certain vertical height corresponds to a certain
depth of fall, and the divisions are marked accordingly. Usually
matters are so arranged, that a glass, eight inches high, shall
contain half an inch of rain ; this permits the divisions, each of
the value of T-^oth of an inch, to be tolerably far apart.

Another rain-gauge in common use is represented by Fig. 2.
It is heavier and more expensive than Howard’s, but may be a
fixture, inasmuch as the water is drawn off from the tap below,
and, by the glass tube, analogous to that used to indicate the
quantity of water in a steam boiler, the amount of rain collected
can be ascertained by inspection. The employment of this gauge
has no other advantage than a slight saving of trouble, an insuf-
ficient compensation for the increased cost. A third very com-
mon gauge is represented by Fig. 3. It seems scarcely necessary
to explain the engraving.

The site selected for a rain-gauge is a matter of some moment
— 1st, as to elevation : It is well known that, according as a gauge
is near the ground, or fifty feet above it, the rain collected will
differ by a large amount. One foot above the surface will be
found a reasonable height ; that clears the splashing from the
soil, and as the gauges are usually made about a foot high, its
base then rests on the actual ground. — 2nd, as to surrounding
objects: The gauge must be placed in as open a situation as
possible — fifteen or twenty feet away from any wall or shrub —
and a greater distance still from a house or tall trees.

There is a diversity of opinion as to whether observations
should be made (1) at 9.0 p.m. and entered as belonging to
the same day, or (2) at 9.0 a.m. and entered as belonging to

* For the practical object I have now in view, it is needless to say more on
this subject.

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TOPULAR SCIENCE REVIEW.

the day before, or (3) at 9.0 a.m. and entered for the day on
which the readings are taken. I adopt (3), believing it to be not
only the most rational, but also the most general plan ; but at
the Greenwich Observatory, they follow (1), whilst the British
Meteorological Society recommends (2).

In reading the graduated measure, the level of the water is
to be taken to the nearest graduation, whether above or below,
giving the benefit of a doubt to the higher one. This will,
from month to month, compensate fairly for loss due to evapo-
ration and capillary adhesion to the sides of the receiver. Some
observers read oftener than once in twenty-four hours in hot
weather, the better to avoid the consequences of evaporation, but
I doubt this being necessary, at any rate for general purposes.

Snow is to be melted, and the product treated as rain ; but,
except when the fall is slight, the rain-gauge must be super-
seded, or snow may be lost, owing to wind having blown it out
of the funnel ; and still more, owing to the funnel being inca-
pable of containing any considerable depth of it. The thing to
supersede the gauge is a cylindrical tube of the corresponding
diameter. Let this be pressed down, in a vertical direction,
through the snow, to the ground, and the snow which is forced
into it will be the amount from which the measurement of the
water should be sought. “ The proportion of snow to water is
about 17 to 1 ; and of hai], to water, 8- to 1. These quantities,
however, may vary, according to the circumstances under which
the snow or hail may have fallen, and the time they may have
been on the ground.” *

In frosty weather, persons using Howard’s gauge will do well
to replace the earthenware jar by a glass wine-bottle, inserted
in some larger water-tight vessel. If the frost bursts the bottle,
the damage done is trifling in pecuniary value, and the contents
are saved by the external receptacle.

Hygrometry. — Hygrometry is that department of Meteorology
which deals with the moisture (scientifically called aqueous
vapour) which is present in the atmosphere. Tomlinson’s re-
marks cannot be improved upon: — “The condition of the air
as to moisture and dryness is of the greatest importance, not only
in the science of the weather but also in domestic economy, in
regulating many processes of art, and in directing the purchase
and selection of various articles of produce. A good hygrometer
will detect the dampness of a room, and indicate the condition
of a magazine, a hospital, or sick ward. Some operations in
the useful arts require dry rooms, others an air inclining to
dampness ; some warehouses also require to be dry, others
moderately damp, while hot houses, green houses, &c., require

* Tomlinson’s Rain-cloud, p. 118 (a very useful book).

Meteorological Instruments.

HOW TO STUDY METEOROLOGY.

145

careful regulation as to moisture. In all such cases the
hygrometer is useful, and if used in conjunction with the baro-
meter, storms of rain or wind, whether on shipboard or on
land, may be predicted.”

Of hygrometers, Daniell’s is an elegant instrument, Regnault’s
elegant and manageable, but Mason’s wet and dry bulb (called,
by the Germans, the psychrometer) is the one for business
purposes. It consists (Fig. 4) of two thermometers, as nearly
similar as possible, placed vertically parallel on a stand, and
about four inches apart. The bulb of one is covered with thin
muslin from which a few threads of lamp or darning cotton
hang down ; these, passing into a small vessel of water below,
keep the muslin and bulb continually moist, and cause this
thermometer to indicate a lower temperature than the other
one, in proportion to the humidity of the atmosphere, the
tendency of objects to dry, or the evaporation going on from
surrounding substances. A small difference in the readings
indicates the presence of much moisture ; but a large diffe-
rence proves the air to be very dry. The temperature of the
dew point can also be arrived at with the aid of this instrument,
this temperature being that to which the air must be reduced
before the deposition of dew will commence.

In taking an observation, begin with the dry bulb, and be
careful always to avoid breathing on or otherwise communicating
heat to the instrument. If the temperature of the air be below
32° the wet bulb may read higher than the dry one. Such a
reading must not be recorded, but the wet bulb must be
moistened, when a coating of ice will form on it, from
which evaporation will take place, though an hour or more
may elapse before the temperature of the wet bulb has fallen
below that of the dry one. If the temperature of the air
should rise above 32°, the wet bulb should be carefully im-
mersed in warm water to melt away any ice which may remain
on it. The temperature of the water must be less than that up
to which the tube is graduated, for if it be greater the. expan-
sion of the mercury will burst the tube at the top, for wTant of
a vent.

To discover the dew point we must employ a table framed
from an extensive series of comparisons executed at the Royal
Observatory, Greenwich, by Mr. Grlaisher, who has concluded
that this temperature may be ascertained by multiplying the
difference between the temperatures of the dry and wet bulb
by certain multipliers, and subtracting the product from the
temperature of the dry bulb.

146

POPULAR SCIENCE REVIEW.

G-laisher’s Multipliers.

Readings of the Dry Bulb
Thermometer.

Multiplier.

Readings of the Dry Bulb
Thermometer.

Multiplier.

o

20

8*1

33

30

21

7-9

34

2-8

22

7-6

35

2-6

23

7-3

36

2-5

24

6-9

37-8

2-4

25

6-5

39-41

2-3

26

61

42-45

2-2

27

5-6

46-50

21

28

5-1

51-56

20

29

4-6

57-64

1*9

30

42

65-73

1-8

31

3-7

74-86

17

32

3-3

1

87-90

1-6

Rule. — Multiply the difference between the two thermome-
ters by the multiplier corresponding to the temperature of the
dry bulb one, and subtract the product from this temperature ;
then the remainder will be the temperature of the dew point.

O

Example : — Let dry hulb tliermometer=58

Let wet bulb thermometer=51

Difference = 7

Then 7xl’8=13‘3.

Then, dew point equals 58° — 13‘3=427°

Lieut. Noble has drawn up a table of factors considered to
be more accurate than these.

It may be observed, that there are many substances to be met
with in nature which are extremely sensitive to variations in
the humidity of the atmosphere, and which may be used as
hygroscojpes , such as wood, ivory, quills, hair, whalebone, animal
membranes, catgut, &c.

A knowledge of the dew point puts us in the track of much
other information connected with atmospheric aqueous vapour, as
will be seen from an examination of Grlaisher’s Tables ; but the
amateur had better disregard such minutise, or he will get
bewildered.

Barometrical Observations. — The barometer measures the
pressure or density of the atmosphere. The meteorologist will
disregard the common notation, 4 Fair,’ 4 Set Fair,’ 4 Change,’ &c.
These terms are not only antiquated and nearly obsolete, but are
often misleading. In real truth, barometers are best without any
remarks of this kind at all ; but inasmuch as the public does not

HOW TO STUDY METEOEOLOGY.

147

consider simple barometrical tubes, which are merely graduated
to inches and decimals, to be barometers at all , Admiral Fitzroy’s
notation should be adopted, if any. What this is, is pretty well
known.

The more expensive barometers read to thousandths of an inch,
but it is submitted that a reading to hundredths is quite suffi-
cient ; and that a good working barometer, answering all the
reasonable requirements of the amateur, need not cost more
than 61.

The due application of the necessary corrections * must not
be neglected. These are, for temperature, sea level, and capil-
larity.

Mercury, like most other substances in nature, expands under
the influence of heat and contracts under that of cold. A read-
ing taken when the thermometer stands at 35° may therefore
seem to differ from one taken when the thermometer is at 70°,
yet the pressure of the atmosphere may be really identical in
the two cases. To make the different readings of a series legiti-
mately comparable, they must be brought to some common
standard of temperature, and meteorologists are agreed that that
shall be 62° of Fahrenheit’s thermometer.

It is well known that the barometer is employed for the
measurement of heights. What does this imply ? Clearly that
the elevation of the mercurial column varies as the elevation
of the place of observation varies ; and such is really the case.
An instrument placed 700 feet above the sea may read the same
as one placed at the sea level, and yet the real pressure of the
atmosphere at the two stations will differ considerably. The
sea level is the standard of altitude ( more Hibernice) to which
it is agreed that all barometrical observations shall be referred.
Speaking roughly, every reading has to be augmented by about
-j^th of an inch for every 100 feet that the place of observation
is elevated above the level of the sea.

The correction for capillarity depends on the well-known
property of all liquids to adhere to solid surfaces with which
they come in contact. A fictitious level is thus given rise to, or,
more accurately, the surface is not level at all, but curvilinear.
When mercury is enclosed in a cylindrical tube of small dia-
meter, such as a barometer tube, the surface is convex, and a
subtractive correction must be applied to every reading. The

* For tables of these, of course in the present article I have no space.
They will be found in various books.

Rise for N. Ely.

N.w.; X.E.

Dry, or less wind.
Except wet from. N. Ely.

S.E.j S.W.

Wet, or more wind.
Except wet from N. Ely.

Fall for S. Wly.

148

POPULAR SCIENCE REVIEW.

smaller the bore of the tube the greater the correction, hence
one advantage of having tubes of large bore, fths of an inch
or more.

When great nicety is required there is a fourth correction,
namely, that for index error, to he taken into account ; but
when the instrument is a good one, and is only read to hun-
dredths of an inch, this correction is, or ought to be, too insig-
nificant to demand notice.

The time for taking observations of the barometer is 9 A.M.
and 3 p.m., but when two readings a-day cannot be managed, it
is best, as it is also most convenient, that the observer should
confine himself to the forenoon hour. The height of the metal
should be taken as from the summit of. the convexity of the
curved surface due to capillarity, which is discussed above.

The subject of Weather Prognostications as derivable from
the study of the barometer is too large a one to be examined in
a paper like the present; but this, however, is the less to be re-
gretted, because Admiral Fitzroy’s Barometer and Weather
Guide , published by the Board of Trade, lays before the reader,
in a compact compass and cheap form, all, or nearly all, that can
be said on this topic.* As to the Aneroid Barometer, I suppose
I ought to say a few words. This instrument is rising in public
estimation, and a first-class one is capable of doing good service
to the traveller, to whom portability is an essential object ; but
the stationary observer will not for one moment set it against a
mercurial barometer, unless it be for domestic purposes.

Temperature. — When a sudden extreme of temperature arises,
be it of heat or be it of cold, everybody becomes an enthusiastic
thermometrician , if I may be pardoned for coining such a work.
It is to be regretted that this enthusiasm is usually so epheme-
ral, because the laws of nature, as regards weather and tempera-
tures, though no doubt in one sense obscure, are nevertheless
full of interesting coincidences.

To describe such a common instrument as a thermometer
seems superfluous ; rather let us dwell on the way of using it.
The most comprehensive method of determining the annual
temperature of a place is by observing daily the maximum and
minimum temperature of the air during every complete period
of 24 hours, and taking the arithmetical mean of the two read-
ings as ‘the temperature of the day. Thus, let us suppose that on
Monday, April 1, 1867, at 9 a.m., the indices of registering ther-
mometers showed that during the previous 24 hours the highest
temperature of the air had been 62*5° and the lowest 40*7°
From these data we conclude the mean temperature of the

* This pamphlet does not of course go into the “forecast” system: that
is an independent subject — at least the Admiral (who was the best judge)
so treated it.

HOW TO STUDY METEOROLOGY.

149

period to have been 51*6°, and the range 21*8°, both of which
should be entered in columns of the observer’s book provided
for the purpose.

Many forms of self-registering thermometers have been con-
trived, but I deem it unnecessary to speak of more than three
here; viz., Sixe’s, Eutherford’s spirit minimum, and Phillip’s
mercurial maximum. Sixe’s provides for the registration of
maximum and minimum temperatures by a single arrangement.
It is a handy instrument, and a well-made specimen will give
good results to within whole degrees, but it is liable to get out
of order, and is expensive of repair. Eutherford’s minimum
thermometer is a spirit one, with the tube horizontal. The
spirit, in sinking by a depressure of temperature, draws the
index with it, but when a rise occurs the index remains behind,
and its end, farthest from the bulb, shows the greatest depres-
sion since the previous observation. The instrument is set for
further use by a gentle tap, which brings the index to the top
of the column of spirit, wherever that may happen to be. In
Phillip’s maximum thermometer a small portion of the mercury
is separated from the bulk by a bubble of air. When the tem-
perature rises, this detached portion is pushed forwards, but
when the temperature falls, it does not recede with the main
body; consequently it marks the maximum temperature that has
occurred since the previous observation.

Concerning simple non-registering thermometers, I need do
no more than give some tests for them, using the words of an
eminent living physicist and chemist. “When immersed in
melting ice, the column of mercury should indicate exactly
32° F. ; when suspended with its scale immersed in the steam
of water boiling in a metal vessel, the barometer standing at 30
inches [the place of observation being at the level of the sea],
the mercury should remain stationary at 212°. When the
instrument is inverted, the mercury should fill the tube, and
fall with a metallic click, thus showing the perfect exclusion of
air. The value of the degrees throughout the tube should be
uniform. To ascertain this, a little cylinder of mercury may be
detached from the column by a slight jerk, and on inclining the
tube it may be made to pass from one portion of the bore to
another. If the scale be properly graduated, the column will
occupy an equal number of degrees in all parts of the tube.”

Thermometers should be hung on a proper stand, facing the
north and protected behind and laterally from the direct rays of
the sun, yet not so as to impede the free access of air.

Thermometers of a certain sort can be obtained for a shilling,
but I need hardly say, these are philosophical toys rather than
meteorological instruments. Let the amateur beware of them.
A good observatory thermometer costs at least fifteen shillings,

150

POPULAK SCIENCE KEVIEW.

and if it be one of those branded K. 0., that is to say, one that
has been tested at the Kew Observatory, so much the better.
In reading thermometers, care must be taken to avoid the dis-
turbing influence of the heat radiated from the observer’s body ;
that is to say, the observer must approach his instruments, read
them as quickly as possible, and retire again, especially taking
care to hold his breath.

Clouds. — The indications of clouds are, when rightly under-
stood, more important than might be supposed.

Howard first reduced them to an orderly classification, and his
nomenclature is now generally accepted. The following is an
epitome of it : —

There are three primary forms of cloud and four secondary
ones.

Primary Forms . — 1. Cirrus . — Fibres extensible in various
directions : these fibres often resemble feathers, wisps or locks
of hair. Generally seen in groups after severe weather, and
when the air is in gentle motion. The highest of all clouds.

2. Cumulus . — A cloud formed of dense aggregations of con-
vex masses, rising from a horizontal base into irregular moun-
tainous rocky heaps, often with white snowy woolly tops. It
characterises dry, fine summer weather. Before rain, it ap-
proaches the earth and becomes more dispersed, and the woolly
features more prominent.

3. Stratus . — An extended continuous stratified aggregation.
It forms at sunset, and disappears at sunrise. The lowest of
all clouds.

Secondary Forms. — 4. Cirro-Cumulus. — Cirrus fibres com-
pressed in rounded masses or woolly tufts, disposed, in a measure,
horizontally. In warm and dry weather, and especially in sum-
mer, it floats at different heights in detached rounded groups.

5. Cirro-Stratus. — Cirrus fibres, as if squeezed together by
forces operating above and below, which results in a stratifi-
cation. Solar and lunar halos, mock suns, and mock moons
display themselves in clouds of this class.

6. Cumulo- Stratus. — Cumulus and stratus clouds inter-
mingled. Large fleecy cumuli rising from or seemingly pierced
by stratus clouds. When black or bluish near the horizon, it is
passing into —

7. - Nimbus. — A dense continuous sheet of almost uniform
black or grey tint with fringed edges. This is the rain-cloud.
The rainbow belongs to it.

Small stray fragments of cloud floating about in the air are
termed scud. In noting clouds, it is sufficient to designate them
by the numbers above, to save space and trouble. Daily records
should be taken, if possible about 9 a.m. and 3 p.m., of the

HOW TO STUDY METEOROLOGY.

151

amount of cloud visible, the scale being 0 — 10. The 0 repre-
senting a clear sky, and 10 a sky wholly overcast.

Wind. — Observations on the Wind cannot in general be car-
ried out by amateurs in any very complete manner. Eye obser-
vations are rather unsatisfactory, and serviceable mechanical
apparatus is necessarily complicated and expensive. For these
reasons it will be sufficient to make this a short section.

A wind- vane can be procured from any good ironmonger ; the
erection of it, however, requires care. The site must be very
open, whether the vane be mounted on the top of a pole rising
from the ground or on one rising from a building. It must, of
course, be correctly “ orientated.” This must be done by com-
pass, allowance being made for the deviation; and as the whole
operation may be a troublesome one, the workmen employed
must be closely watched.

Contrivances for registering information as to the wind are
called anenometers. Eobinson’s is recommended by Sir H.
James, as “ simple in its construction, and is not liable to get
out of order, whilst it registers the velocity of the wind at any
moment, or the current of air passing the station during the
hours between the periods of observation.

“ It consists (Fig. 5) of arms, at the end of which there are four
light hemispherical hollow cups, which, as Dr. Eobinson has
demonstrated, i*evolve with one-third of the velocity of the cur-
rent of wind acting on them. On the vertical axis which carries
the arms, there is an endless screw, which communicates its
velocity of rotation to a circular index.

u This index has two graduated circles, the outer one of which
is graduated for five miles from 0 to 500, and the inner one into
five miles, each mile divided into furlongs. The movable hand,
from the centre, indicates the number of miles of air in the
current which has passed the station, as 5, 10, 15, whilst the
final hand indicates the number of odd miles and furlongs (as
3 m. 5 f.) at which the movable hand stands, beyond the five mile
graduation. If, for example, the movable hand stands between
15 and 20 on the outer circle, and the final hand indicates
3 m. 5 f., the length of the current 18 m. 5 f.

si The velocity of the wind at any particular moment may be
found by observing the index before and after a certain interval
of time, as one or five minutes, and then multiplying the rate
by 60 or 12 to find the velocity in miles per hour.”

The pressure in pounds per square inch can then be ascer-
tained by reference to a table. A milled head-screw, at the
back of the instrument, turns the movable index, which should
be brought back to zero after an observation is registered. The
instrument requires to be erected in some open situation, easily
accessible to the observer, but freely exposed to the wind.

VOL. vi. — NO. XXIII. N

152

POPULAR SCIENCE REVIEW.

Casella, for portability, makes the arms to fold. The instru-
ment can be mounted on a piece of gas pipe or otherwise.
Further, it is available for ascertaining the ventilation of places
of public resort; an inspection showing at once the progress of
the current of air circulating above the heads of an audience.

Lind’s anenometer (Fig. 6.) is a portable and elegant little
instrument. A column of fluid, descending in a tube of about
i-inch bore, and ascending one of J-inch bore, shows, on a
graduated scale, the pressure of the wind on a square foot, and
its velocity. A light arrow-shaped vane is placed, when required,
upon a point on the upper edge of the instrument, to indicate
the coincidence of the mouth-piece with the direction of the
wind, and a small plummet line, protected by plate glass in the
body of the scale, indicates the true perpendicular position of
the instrument.

Other anenometers in use are. Osier’s, Whewell’s, and Catox’s,
but, for reasons stated above, the}^ are unsuited to the use of
amateurs, and therefore I say nothing about them. In the ab-
sence of an anenometer, it is usual to record the force of the wind
guessed , rather than estimated, by noting it on a scale of 0 — 10,
0 representing calm, and 10 a terrific hurricane. The progres-
sion adopted is usually as follows, but the whole thing is, in
the highest degree, vague and unsatisfactory : —

0. Calm.

1. Motion of air hardly felt.

2. Light breeze, just perceptible.

3. Gentle breeze.

4. Brisk pleasant breeze.

5. Very brisk breeze : fresh.

6. High wind.

7. Rough squally wind.

8. Very high wind ; gale.

9. Hurricane ; tempest.

10. Violent hurricane, tearing up trees, &c.

In recording the position of the vane no greater nicety need
be attempted than sixteen points of the compass, N., N.NE.,
NE., E.NE., E., &c.

An observatory, specially fitted up for meteorological pur-
poses, will contain divers instruments, with which the popular
observer has no special concern, such as the electrometer, the
actinometer, the cyanometer, the evaporating gauge, the ozono-
meter, &c. For information on points connected with these,
reference must be made to treatises on meteorology, of which,
by the way, there is a great dearth. The ordinary amateur will

HOW TO STUDY METEOROLOGY.

153

find his time and energies sufficiently taxed by working at the
subjects I have dealt with, I fear, very imperfectly, in the fore-
going pages. Far better is it to take up and stick to a few
things, than to attempt everything and break down in a few
months.*

* For the Illustrations in this article I am indebted to Mr. Casella, of
Hatton Garden.

ON SENSITIVE FLAMES.

By W. F. BARRETT,

Lecturer on Natural Science at the International College.

SENSITIVE flames, as they have appropriately been called,
are flames which, by their sudden movement at the slight-
est sound, evince a wondrous susceptibility to the influence of
sonorous vibrations. The story of their discovery is briefly this.
In the year 1865, whilst engaged in the preparation of the ex-
periments for the Christmas lectures at the Royal Institution,
the writer of this article observed that a shrill and prolonged
sound had a curious effect on a tall and slender gas-flame which
happened to be burning near. Under the influence of the sound
the flame, which was about 14 inches long, shortened itself
several inches ; at the same time the upper part spread out side-
ways into a flat flame, which gave an increased amount of light
from the more perfect combustion of the gas. Less strongly,
the same effect took place when a high note was uttered or
played even so far off as 30 or 40 feet away. So strange an
occurrence could not be permitted to pass without further
investigation; as soon as possible, therefore, I submitted the
observation to a brief examination, in which I succeeded in
finding some of the conditions of success of this singular phe-
nomenon, and so exalting the action that the flame moved at
every noise. The results of this inquiry I showed to Professor
Tyndall in the early part of last year, and did not then make
any further publication of the matter.

I next sought to ascertain if the effect had been previously
noticed, but could discover no published account of a similar
experiment. I learnt, however, that mechanics sometimes
observe the large bat’s-wing gas-flames in their workshops to
become disturbed, and throw out little tongues of flame, when
the noise of their work happens to be sustained and shrill. I
next heard, through Professor Tyndall, that an American gentle-
man, Dr. Leconte, had noticed and published an account of an
analogous effect to this last, but not until recently did I read
the following extract from his paper on the subject. After re-

SENSITIVE FLAMES.

155

marking that he was at an evening party in which there was a
performance on musical instruments, and that the room was
lighted by the so-called fish-tail gas flames. Dr. Leconte says : —
u Soon after the music commenced, I observed that the flame of
the burner exhibited pulsations in height which were exactly
synchronous with the audible beats. This phenomenon was very
striking to every one in the room, and especially so when the
strong notes of the violoncello came in. It was exceedingly
interesting to observe how perfectly even the trills of this
instrument were reflected on the sheet of flame. A deaf man
might have seen the harmony. As the evening advanced, and
the diminished consumption of gas in the city increased the
pressure, the phenomenon became more conspicuous. The
jumping of the flame gradually increased, became somewhat
irregular, and finally it began to flare continuously, emitting
the characteristic sound indicating the escape of a greater
amount of gas than could be properly consumed. I then as-
certained, by experiment, that the phenomenon did not take
place unless the discharge of gas was so regulated that the flame
approximated to flaring. I likewise determined that the effects
were not produced by jarring or shaking the floor and walls of
the room by means of repeated concussions. Hence it is obvious
that the pulsations of the flame were not owing to indirect vi-
brations propagated through the medium of the walls of the
room to the burning apparatus, but must have been produced
by the direct influence of aerial sonorous pulses on the burning
jet,”

The paper from which this extract is taken was published in
Silliman’s American Journal for January 1858, and in the
Philosophical Magazine for March 1858 ; but though thus an-
nounced nine years ago in America and England, Dr. Leconte’s
observation does not appear to be generally known in either
country. It will be noticed that it is the converse of mine ;
differing from it, however, in some respects. Thus, as regards
change of appearance and the amount of visible motion, the
shrinking of the tall flame far exceeds the spasmodic jumping
of the fish-tail: and further, although at first both flames
were only affected by the prolonged action of a musical sound,
yet subsequently the upright flame was caused to shrink at
any noise ; whilst Dr. Leconte remarks the fish-tail flame was
uninfluenced by noises of any kind, but always required the
energetic and sustained vibration of a musical note. Dr. Le-
conte, however, made the happy and important observation,
that his flame did not jump until the pressure of the gas caused
it to be near flaring. This, as will be seen in the sequel, is the
key-note to the whole phenomena.

Professor Tyndall next took up the subject, and increasing the

156

POPULAR SCIENCE REVIEW.

pressure of the gas, as indicated by the American physicist,
enriched the experiments and brought the subject so under
command as to raise them to the dignity of a Friday evening
lecture at the Eoyal Institution. It was in this elegant lecture
demonstration of January 18th last, that Dr. Tyndall gave at
once the name and publicity to “ Sensitive Flames.”

So much for the historical part of the subject. Let us now
describe more in detail how gas flames may be rendered sensi-
tive, and what they are capable of exhibiting when in this state.

In my investigation of the shrinking flame the gas was used
direct from the main. The flame burnt, therefore, under the
ordinary pressure attainable by everyone. The most essential
condition of success is the shape of the burner whence the gas
issues. The one I found to succeed the best is shown in the
annexed drawing, fig. 1, where it is represented of its real size.

It is formed of a piece of glass tubing, about f ths of
an inch across, contracted at one end to a tapering ori-
fice -jL-th of an inch in diameter. This orifice must be
slightly v-shaped, as shown in the figure. It is only
the work of a minute to form such a burner. A short
length of glass tubing, softened in a gas flame, is readily
drawn out to a point, the extreme end of which must
be broken off ; and the aperture can then be enlarged,
and snipped into the shape indicated by means of a
pair of scissors. Connecting this burner with the gas
pipes, by means of some flexible tubing, it should be
continually tested with the sound of a whistle whilst it
is being trimmed into shape. I have always found this
rough and ready mode of making the burner to answer
very well. A more permanent burner can also be
formed of a gas-fitter’s brass blowpipe, straightened and
filed to a rather larger and v-shaped aperture ; or it
^S* lm may be made of a bit of compo gas piping hammered at
one end into a tapering orifice. A little patience and experience
will soon bring success, of whatever material the burner be
made.

When any one of these properly shaped burners is connected
with the gas pipes, the stopcock being fully open, a tapering
flame about 15 inches long is obtained. The sound of a
whistle, or the higher notes of a musical instrument, or even a
noise, as clapping the hands or tapping the table, totally alters
the shape and character of this flame. Immediately the sound
is made, the tall quivering flame shrinks down nearly half its
height, and spreading out laterally into a fish-tail flame, gives a
largely increased amount of light, from its better exposure to the
air. On the cessation of the sound, the flame again rises to its
original height. The difference between the two flames is shown

SENSITIVE FLAMES.

157

in Plate VIII. Fig. 1 is the tall flame, with its dull, smoky, un-
steady appearance, and its loose, ill-defined shape. Fig. 2 is
the same flame under the influence of sonorous vibrations ; it
has fallen a height of six to nine inches, and widened out some
three inches ; the half-burnt gas, the clouds of carbon, the lack
of definition have gone, and all this wondrous change has been
brought about by the influence of a little noise.*

Some amusing experiments, dependent on this change in the
luminosity and shape of the flame, at once suggest themselves.
One may retire to such a distance from the flame that small
print shall be illegible, but, by whistling, the flame maybe made
to diverge, and as long as you whistle you can see to read. Still
more effective for lecture illustration is the following. When
the flame is burning upright, any combustible substance, as
matches, gunpowder, gun-cotton, or a strip of paper, may be
placed about an inch from the middle of the flame. A stroke
on the c above the treble of a piano, a whistle, or a clap,
will at once diverge the flame and ignite the neighbouring sub-
stances.

This remarkable change in the aspect of the flame is wrought
solely by the effect of sonorous vibrations, and is not at all due
to the impact of the puffs of air which may have attended the
production of the sound. Nothing material has been translated
to the flame. The particles of air, if ever so violently displaced,
could not struggle onward, even for a short distance, through
the entangled barrier produced by their surrounding neighbours ;
and, could they reach the flame, their impact would be incompe-
tent to produce an effect so strange and sure. It is solely the
wave-like, to-and-fro motion of the air, by which sound is pro-
pagated from place to place, that has caused this change. It is
the product of translated motion , not of translated matter .
But any lingering doubt as to the possibility of some tangible
connection with the flame will speedily disappear. Let a person
go whistling out of the room in which is the sensitive flame,
and let the door and every opening be closed after him. If he
continue to whistle, the flame will still respond, though with
enfeebled power as the distance increases and obstacles arise in
the path of the sonorous waves. Still let your friend go on
whistling, as he retreats into some upstairs room two or three
stories away. The flame, if properly sensitive, will be visibly
affected every time the faint sound of the whistle is heard. The
velocity with which sound is propagated is here well illustrated,
the movement of the flame being' simultaneous with the hearing
of the sound.

* For the representation of these flames and the other drawings on the
plate, I am indebted to the skill of my friend Mr. Hedman.

158

POPULAR SCIENCE RETIEW.

It is very wonderful to reflect, how almost infinitely small is
the amount of vibratory motion here rendered evident by our
sensitive flame. The molecular motion of the air excited by a
sound does not diminish merely in proportion as the distance
increases, but far more rapidly : it is inversely proportional to
the square of the distance. Remembering this, and that a de-
cided action upon the flame was produced by no very loud sound,
made at a distance of thirty or forty feet away, we are startled at
the smallness of the motion capable of producing so sensible an
effect. Further, when we add to the diminution by distance,
the great enfeeblement of the motion uf the sound waves in
overcoming the solid obstacles that intervened between them
and the flame, the result is still more amazing, and, were it not
attended wflth the certainty of a natural fact, one would be in-
clined to doubt its truth.

A sensitive flame, such as here described, can be applied to
many purposes of experimental illustration. For instance, it
may be used to indicate the fact that, a body, when sounding,
divides itself into vibrating segments, separated by intervals of
rest. This is usually shown by the unequal disturbance of
some solid, placed on the vibrating body ; but, for an audience,
who cannot look down on the lecture table, this method is open
to objection. A gas flame, which need not be very sensitive, can
then be used with advantage. If, for example, a large brass
plate, fixed at its centre, be thrown into vibration by means of
a fiddle-bow, a strained and intense divergence of the flame
is obtained, when the higher notes of the plate are sounded.
Holding the plate thus sounding, close to and parallel with the
flame, and moving it slowly, so as to bring different parts in
succession opposite the flame,* the principal nodal lines can be
traced as easily as with sand. The intervals of rest in the vibra-
ting plate allow the flame to raise itself up, and, in its sluggish
combustion, to stand, as it were, at ease, whilst the ventral seg-
ments drag it down to active burning and soldierly attention.
Again, the so-called beats , produced by the interference of
nearly unisant sounds, can be rendered more apparent by the
movement of the flame. Striking, with a fiddle-bow, a large
bell, or the brass plate above mentioned, these beats, though but
faintly audible, cause evident changes in the flame. At every
beat, the momentary silence allows the flame partially to regain
its original height, from which, however, it is almost imme-
diately thrown down by the sound which follows, erecting itself
at the next beat, only to be thrust back as the sound again
wells up. Thus, a sort of breathing flame is produced, the
aspirations of which are strictly timed to the sighing of the
bell.

But it is not to every sound that the flame is equally sensi-

SENSITIVE FLAMES.

159

tive. However loud a note may be, if below a certain pitch,
it will have no effect on the flame. This influence of pitch is
well illustrated by running up the scale of a piano-forte ; the
bass notes do not disturb the flame in the slightest ; but, as the
high notes are approached, the flame becomes uneasy, and at
last diverges strongly, when the third octave in the treble is
reached. The strings in this octave make from 2,000 to 4,000
vibrations a second. Moreover, the note which exercises the
most influence on the flame, is not the same for all burners.
I have in my possession a series of glass burners, each of which
gives sensitive flames ; the orifices are of different sizes, and the
flames are variously influenced by whistling the notes of the
gamut. It appears that the smaller the orifice in the burner,
the higher is the pitch of that note which most powerfully
affects the flame. And, I have no doubt that, by means of a
large and proper orifice and low pressure, a flame might be
made responsive to grave sounds.

With differently shaped burners effects complementary to those
previously described have been obtained. Thus, the original
flame may be of a fish-tail appearance, like fig. 2 in the plate.
At the sound of a whistle, the flame rises into the tall, smoky
flame shown in fig. 1, sinking back into the forked and flat
shape the moment the sound ceases. It was an incipient effect
of this kind that was noticed by Dr. Leconte in his fish-tail
burner. With a large sized batswing burner the phenomenon
is rendered more striking. The beautiful sheet of flame which
this burner gives is split up into numerous tongues, at the sound
of a whistle. This change is represented in fig. 2 : a is the

quiescent flame, b the same flame, under the influence of the
sound, thrusting out its fiery fingers.*

* This experiment is Dr. Tyndall’s, to whose kindness I am indebted for
the drawing from which this cut is taken, it being one of the illustrations
in his forthcoming book on “ Sound.” To that work the reader is referred

a

b

Tig. 2.

160

POPULAR SCIENCE REVIEW.

Except this last experiment, which requires an additional
pressure on the gas, all the foregoing experiments can be re-
peated merely by attention to the shape and size of the burner,
having the stopcocks and gas passages as widely open and free
as possible, and using the gas under the greatest pressure
obtainable from the main ; hence the dusk of the evening, when
this pressure appears to be at its maximum, is the best
time for repeating these experiments. The same burner may
give a flame not sensitive at one time of the day, but very sensi-
tive at another, and the pressure may become so great that the
flame may again lose its sensitiveness. Other burners, as the
batswing, require a greater pressure than that which is given
from the gas works to make them sensitive.

To obtain, therefore, the most complete results we must our-
selves increase the pressure of the gas. This can be done by
filling a gas-holder or gas-bag with coal-
gas, and forcing the gas therefrom ; or,
lacking these, a useful substitute can be
found in an india rubber air pillow, which
must have its screw replaced by a stopcock.

Through a flexible tube the gas can be con-
ducted from its reservoir to the burner,
which may be held fast in a clip, or other
support. All that is now necessary is to
bring the gas very near to the point at
which it gives a roaring noise as it issues
from the burner. This is accomplished by
altering the weights on the bag, or adjust-
ing the stopcock
of the holder.

The general ar-
rangement of
the apparatus is
shown in Fig. 3.

Under this
increased pres-

Fig. 3.

sure other burners can be used beside the shape shown in fig. 1 .
A circular iron nipple can be employed, or still better, a burner
made of steatite or silicate of magnesia, a substance which has
the advantage of expanding so slightly by heat, and being un-
corroded by use, that practically the size of the orifice remains
always the same. Selecting one of these steatite burners having
a single circular orifice, *046 inch in diameter, or just admitting
No. 19 wire, and igniting the gas which is urged from it, a

for further information, and, I need hardly add, what is sure to he the most
lucid exposition of the subject of u Sensitive Flames.”

SENSITIVE FLAMES.

161

sensitive flame is obtained of a new character, and of extraordi-
nary susceptibility to certain sounds.*

Uninfluenced by sound this flame can be made to attain a
height of full twenty inches, burning with greater steadiness
and less smoke than that shown in Plate VIII. fig. 1, but having
the same long and tapering character as the flame there drawn.
The effect of sound on this flame reduces it to a very different
shape from, that of fig. 2 on the plate ; at the noise of a tap it
shrinks down half its height, or nearly a foot, the upper part
becomes thick and bushy, the lower remains unchanged ; and,
instead of burning more steadily and with a better light under
the influence of sound, it becomes tumultuous and less luminous.
In this state it is shown at fig. 3 on the plate, having, it will be
noticed, irregular little coruscations clinging and flickering up
its sides. We will call fig. 2 the divergent, and this, fig. 3, the
brush flame. It is a wonderfully delicate flame. Like a sensi-
tive, nervous person, it starts and shrinks at every little noise;
the change in its aspect being so great as to cause it to be one
of the most striking and effective of all the sensitive flames.
But, most curious of all, this flame is especially sensitive to the
letter S, or any sibilant sound. Tell it to appear as a “ brush,”
and it instantly obeys, vigorously assuming its characteristic
shape, shown in fig. 3. Say to it “hush,” and at once, with a
spiteful, fluttering noise, it cowers down nine inches. A whis-
per, too, being rich in sibilants, is at once detected by the flame,
which crouches, as if to listen, the moment you move your lips.
Like most sensitive people, it keenly feels the effect of a “ hiss.”
Let it hear you make such a sound, and it drops from its lofty
height, shrinking into a foolish, fussy little flame, which, as
though in agony, fairly begins to roar if you venture to sustain
that disparaging sound. Even if you go far away and out
of sight, the flame will shiver all over every time you utter the
obnoxious sibilant.f

But this flame, like the others, is not at all sensitive to some

* This flame was first noticed by Dr. Tyndall, and the associated experi-
ments shown by him at the Friday evening lecture to which reference has
been made. To obtain the flame it is not at all essential that the burner
should be of steatite, but it will be noticed that the orifice is smaller than
that of the burner previously described.

f In a note attached to a paper on sensitive flames, published in the
March number of the Philosophical Magazine , I have drawn attention to
other remarkable peculiarities which are associated with the sound of the
letter S. I have frequently noticed that when any sibilant is uttered
simultaneously by a large assemblage of people, the resulting sound is far
different in intensity to that of any other — a striking noise being produced,
like the escape of steam from a high-pressure boiler. It is worthy of
remark that the Astronomer Royal believes the sound of the letters S or Z
to be produced in a manner different from the rest; namely, by an in-
terruption in the continuity of the particles of air.

162

POPULAR SCIENCE REVIEW.

sounds ; it is only the high notes which affect it. If the strings
of a violin be struck, the grave notes produce no alteration,
whilst the highest ones violently urge it down. Hence, if a tune
be played on a musical instrument, the flame, variously affected
by the different notes, dances in perfect time to the music. Still
more striking is this action when a musical snuff-box is set
going, and placed near the flame. Indeed, so very magical is
the unseen connection between the instrument and the flame,
that at first sight the experiment seems more appropriate for a
conjuror’s stage than a scientific lecture table : but are not the
experiments of the philosopher always more wonderful than the
tricks of the conjuror?

In the same way that the flame responds to certain notes of
musical instruments, so it picks out, and is more or less moved
by various vocal sounds. Eepeating, in the same pitch, the
vowels to the flame, it will be seen that the sound of u cannot stir
the flame, whilst e affects it powerfully, and ak still more ener-
getically. The cause of this is found in the fact, that in the latter
sounds there are present higher tones which are absent in the
first, and it is to these over-tones, or harmonics, of the funda-
mental note common to all the vowel sounds, that the agitation
of the flame was due. If, therefore, we address the flame, it
curtsies, bobs, and bows, or remains unmoved, just as the words
we utter may happen to contain more or less, or none of those
high notes, to which this flame is peculiarly sensitive.

Hence the reason why the flame is so intensely agitated by a
noise. For this unmusical sound is caused by an admixture of
various notes, and among them, especially if the noise be of a
certain class, are sure to be found a few of those notes which
most largely influence the flame. The sound of the gentlest
tap, the chinking of money, the creaking of boots, the crackling
of a fire, the dropping of a cinder, and even the splashing of a
rain drop and the ticking of a watch, all startle or convulse the
flame. Whilst the crumpling of tracing paper, or the rustling
of a silk dress, sets it frantic with commotion.

What, let us now ask, is the explanation of these remarkable
phenomena ? {Seeking to know the cause of what I had observed,
I was led to notice last summer, that an increased pressure of
the gas acted precisely like a shrill sound in shortening the flame.
Dr. Leconte has, however, the prior claim to this observation,
which has been raised by Professor Tyndall to an explanation
of the phenomenon, given in the following words : — “ The gas
issues from its burner with a hiss, and an external sound of
this character added to that of a gas-jet already on the point of
roaring, is equivalent to an augmentation of pressure on the
issuing stream of gas.” # This statement holds good for all
* Philosophical Magazine } February 1807, p. 99.

SENSITIVE FLAMES.

163

kinds of sensitive flames. They all stand, as Professor Tyndall
puts it, on the brink of a precipice, over which the sound
pushes them. If the pressure be increased, they shorten and
roar, and the sound has the same effect : tc The sonorous
pulses, in fact, furnish the supplement of energy necessary to
produce the roar and shorten the flame.”

Some may object to this explanation, on the ground that it
is inconceivable so small an amount of wave motion as in some
cases reaches the flame could sensibly affect the pressure of the
gas. Though this does seem a difficulty, still the amount of
increased pressure necessary to make a gas-flame roar, when it
is on the point of doing so, is wonderfully small. I have been
informed by Mr. Sugg, the gas engineer, that an increase of
pressure equal to the depression of a column of water through
the space of only the hundredth of an inch can cause the flaring
of a fish-tail gas-flame. Through the kindness of the same
gentleman I have been able to determine the point at which
a flame becomes sensitive under increased pressure. With a
steatite burner just admitting No. 19 wire, the flame was sensi-
tive at pressure of a inches of water, but was at its best, and
on the point of roaring, at 3^- inches. With a smaller sized
burner, admitting No. 21 wire, the flame began to be sensitive
at 5 inches pressure, and was at its best at 6 inches. Further
increase of pressure, in either case, caused the flame to shrink,
and take precisely the appearance it has when under the
influence of sound, as in fig. 3 on the plate.*

It must, however, be acknowledged, that the explanation just
given does not clear up the difficulty, for as yet its distinguished
author has not shown how an external sound can produce an
effect equivalent to an augmentation of pressure. Moreover,
it does not, I apprehend, account for the fact that only notes of
a certain pitch affect one flame, nor why different notes influence
different flames.

Further light seems to be thrown on the matter by a critical
examination of the flame in its various states. To accomplish
this, we must exalt the sensibility of our vision by adopting

* The gas here used was cannel, hut the quality of the gas will ddiibt-
less greatly influence the result. Issuing from the same orifice, and under
the same pressure, cannel gas gives a far higher flame than the common coal
gas. Indeed, this difference in the height of the flame is the principle of
what is known as the jet photometer. This instrument consists merely of a
jet of gas, issuing from one of these steatite burners, burning in front of a
graduated scale. A very slight change in the illuminants contained in the
gas causes a marked alteration in the height of the flame. If the flame
happens to be near flaring, it is evident that shrill sounds should be avoided
during the observations of such a photometer : in fact, the burner which at
the least pressure gave me the most sensitive flame was the very one
which had been discarded from photometric use on account of the irregu-
larity of its indications.

164

POPULAR SCIENCE REVIEW.

the ingenious suggestion of Mr. Wheatstone, which consists in
causing the image of the flame to travel over different parts of
the retina, by looking at the reflection in a moving mirror.
Examined in this way, a steady jet of gas gives an uninterrupted
band of light, like a glowing stick whirled in the air, but the
continuity is broken when the flame begins to roar, for then a
number of images are seen with dark spaces in between.*

In this case the flame is nearly blown out by the rush of gas,
but rekindled before it is quite extinguished, and this alternate
action, rapidly kept up, constitutes the flicker of a candle and
the roar of a gas flame. When roaring, therefore, a flame is in
a state of rapid vibration, and it is this vibration which pro-
duces the succession of images seen in a moving mirror.

Now, imagine a sound to be made in a room wherein a steady
jet of gas is burning ; the flame, along with other things in the
room, is thrown into a state of vibration corresponding with the
sound. The flame, being most easily disturbed, will be the
most agitated, but will not be perceptibly affected, unless it be
near its sensitive point. Now, permit an increased flow of gas
to issue from the burner, so that the flame shall be just at its
sensitive point, that is, if the gas ripples a little faster through
the orifice the flame will change its shape and be thrown into a
state of vibration. Let a sound be again made — if the vibra-
tions now excited in the flame happen to be synchronous with
those which the flame only lacked, in order to make it roar,
then, those vibrations being superinduced by an extraneous
source, the flame will accompany its response to the sound by a
change in its shape. Hence, a sensitive flame is the analogue
of a resonant column of air; both are caused insensibly to
vibrate at any note, but when the pitch of the note accords
with the normal rate of vibration of the flame or the air, then
the flame visibly, and the column of air audibly, responds with
energy to that note. So that bringing the flame to the point at
which it is sensitive to a particular note, is like adjusting the
length of a column of air until it resounds to a certain tuning-
fork.

'fhat a sensitive flame, under the influence of sound, is in a
state of rapid vibration can readily be proved. Thus, the flames
shown at fig. 2 and fig. 3 on the plate, when regarded in a
moving mirror, are seen to consist of a succession of flames,

* By varying the motion of the mirror, this effect can he rendered very
beautiful, and nothing is simpler to reproduce. A. bit of looking-glass
twisted to and fro in the hand before a dickering candle, or a roaring gas-
flame resolves these common objects into luminous chains and crowns of
weird and matchless beauty. It is indeed surprising, how we neglect the
beauty which is so lavishly scattered through the great treasure-house of
nature.

SENSITIVE FLAMES.

165

giving the appearance shown in fig. 4. The crossing of the
images is due to the to-and-fro motion of the mirror. The
isochronous vibration of the flame that is here revealed, gives
rise to a musical note in the case of the divergent flame.

But whilst a sensitive flame is most affected by sounds of a
definite pitch, it can also respond to a certain range of vibra-
tions, so that within limits the higher the pitch of the exciting
sound, the more rapid the vibration of the flame. A fine
experiment illustrating this fact can be made by sounding a
musical instrument near the divergent flame, at the same time
looking at its reflection in a moving mirror. With a compara-
tively low note, the images of the flame stand widely apart, as
shown in the plate at fig. 4. Raising the pitch of the note, the
flame vibrates more rapidly, the images seen in the mirror
become more numerous, and link themselves into a reticulated
pattern of exquisite beauty. This is shown in fig. 5, but in
both cases the representation falls far short of the beauty of the
real appearance. As the note rises still higher in pitch, the
network becomes finer and finer, until the eye can no longer
separate the images in the mirror. The value of a flame in
searching the condition of a vibrating body can here be seen,
for in the moving mirror it is easy to detect the frequent ad-
mixture of higher notes with the fundamental tone. At such
times small and numerous images of the flame are observed to
ride on the backs of the large and widely-separated ones. By
means of a concave mirror moved to-and-fro, this effect can
easily be thrown on a screen, and many points in acoustics may,
in this way, be demonstrated in the simplest manner.

Thus have we sought to translate the phenomena of these
sensitive flames from the “ disorderly mystery of ignorance ” into
the “ orderly mystery of science.” For, notwithstanding any
explanation which may be given, the facts remain as wonderful
and mysterious as ever. And science does not remove this
mystery, does not lessen this wonder : it teaches us that we are
surrounded by wonders, that we are enveloped in mystery ; and,
at present, it can do but little more than reveal these wonders,
classify these mysterious facts, and awaken a right and intelligent
appreciation of them.

March 1 1th, 1867.

P.S. — Whilst these sheets were passing through the press,
subsequent experiments and further consideration have led me
to supplement and to simplify the explanation given in this
article. It has been shown, that a sensitive flame is one which,
on the slightest mechanical increase in the pressure, or, what
comes to the same thing, in the velocity of the gas as it issues

166

POPULAR SCIENCE REVIEW.

from the burner, will change its shape, and take precisely the
appearance it has when influenced by sound. Now, the sono-
rous pulses, excited by a sound, throw the pipe which conveys
the gas to the burner into vibration, the flow of gas is thereby
urged from the sides towards the centre of the tube, and, being
confined within narrower limits, issues from the burner with an
increased velocity, so long as the sound continues. This, I
believe, is the simple philosophy of how sonorous vibrations
can effect an increase in the pressure of the gas ; and, it needs
but a little reflection, to see the ready explanation it affords to
every difficulty, e. g., the importance of freedom in the gas-
passages, the superior effect of high notes, and the fact that
the nearer the gas is to the point at which its velocity through
the burner will cause an alteration in the shape of the flame,
the less sustained and the less loud need be the sound which
precipitates this change.

March 20 th.

Plate Yin.

S en pit rve FI ame s.

167

PARAFFIN LAMPS AND THEIR DANGERS.
By JOHN ATTFIELD, Ph.D., F.C.S.

THE oil in a paraffin lamp, as in most other oil-lamps of
simple construction, passes up a wick by capillary attraction,
comes in contact with the brasswork of the lamp in the long
slit or channel which holds the wick, and finally burns at the
top of the wick, by help of a strong current of air. The flame
heats the metal in its vicinity, the heat is conducted downwards
to all parts of the brasswork, and thus every drop of oil that
flows up the wick becomes heated to a temperature of 105 to
110 degrees of Fahrenheit’s thermometer the moment it touches
the metallic slit. According to the quality of the oil, this
temperature is or is not sufficient to convert a portion of the oil
into vapour. If the oil is badly refined, the warm metal causes
evolution of vapour, which mixes at once with the air in the
upper part of the reservoir of the lamp ; at once, because the
portion of the brasswork that is at the above -temperature is
just that portion which faces the interior of the reservoir of the
lamp. This vapour accumulates in the confined air, and the
mixture soon reaches proportions in which it is inflammable.
Should the mixture now catch light, the resulting flame and
expanded products of combustion, having no other vent, will
escape by bursting the reservoir, scattering the oil all around.
The result is, of course, fright to those who witness the accident,
and risk of a conflagration, should the escaping oil happen to
ignite.

The chances against an explosive mixture forming in a lamp
are, at the present time, unfortunately, very small ; for nine-
tenths of the light-coloured American oils met with in the shops
under various names generate the mixture as soon as they are
warmed up to 80 or 90 degrees. It is here only fair to say that I
have not met with a specimen of Young’s oil which gives off in-
flammable vapour below 130 degrees ; I have, however, met with
samples which were, apparently, mixtures of English and Ameri-
VOL. vi. — NO. xxiii. o

168

POPULAR SCIENCE REYIEW.

can oil, and these gave me explosions in an experimental lamp.
The American oils could be rendered non-explosive j ust as easily
as Young’s, but it is against the interest of f the trade ’ to do
this. It is true there is an Act of Parliament, which came into
operation in October, 1862, forbidding the warehousing of much
more than one barrel of American oil, unless proof is forth-
coming that it gives off no inflammable vapour, below 100
degrees; but merchants, brokers, and dealers in the oil con-
sider these words to mean that the oil itself shall not ignite
under 100 degrees, when a lighted match is dipped into it,
which is really a very different thing. For oil that will not
take fire under 100 degrees will readily give off inflammable
vapour at 80 degrees or 90 degrees, and hence always give rise
to an explosive mixture of vapour and air in the reservoir of
the lamp in which it is burnt. Until the letter of the Act is
enforced, therefore, there will always be danger in burning
paraffin oil in the lamps commonly used.

Fortunately the chances against the explosive mixture of
vapour and air catching light in a paraffin lamp are very great.
There is, however, one little hole in the upper part of every oil
lamp, an aperture necessary to the steady burning of the lamp,
and it is this which, doubtless, forms the touch-hole, by which
fire has at times been conveyed from the flame of the lamp
to the mixed vapour and air in the reservoir. But in paraffin
lamps there is always a strong current of air passing over the
external part of this orifice, in its passage upwards to support
the combustion of the flame, and hence the successive portions
of the inflammable mixture which escape through the aperture
are at once so largely diluted with air as to be harmless. Should
this current of air be arrested, as when a lamp is extinguished
by placing a cap over the top of the glass chimney, or when the
flame is put out by blowing down the chimney, or when the
wick is being turned down and the chimney simultaneously
removed by a cloth placed round the lower part of the chimney
to protect the hands, or by other occasional circumstances, then
the liability of the explosive mixture to ignition is greatly
increased. Paraffin oil is an excellent and cheap illuminating
agent, and if traders would only take a little more pains in
refining it, so as to remove as much as possible of the un-
pleasant odour it possesses, and render it as safe as the old
vegetable oils, which could be done with perfect ease, its present
large sale would doubtless be immensely increased.

169

AX ATTEMPT TO APPROXIMATE THE DATE OF THE
FLINT FLAKES OF DEVON AND CORNWALL.

By SPENCE BATE, F.R.S., &c.

THE large number of Flakes and broken fragments of Flints,
found scattered over the surface of the country, has attracted
considerable attention from archaeologists.

In speaking of these flakes, care must be taken not to confuse
them with those tools that are found in the Drifts of England
and France, and which are the result of a more extensive
manipulation than is evidenced in the manufacture of the flint
flakes to which we allude in this paper.

These flakes are to be found on and near the surface of the
superficial soil of the country. In the neighbourhood where
flint is abundant their presence does not strike the observer so
forcibly as in localities where, geologically, flint does not exist.

Throughout the counties of Devon and Cornwall flint flakes
and chips are plentifully scattered. In some localities, such as
in the neighbourhood of Barnstaple, and at the Lizard, they are
abundant, whereas in other districts they are only to be met
with as isolated specimens.

The character and appearance of these flaked specimens are
various, some being well-formed arrow-heads, others representing
the blocks from which the flakes have been struck, and others
representing fragments of most irregular shapes. These last are
more common in districts where the flint flakes are most abun-
dant, but in those localities where the flints are scarce, the few spe-
cimens found generally represent well-formed flake implements ;
and these exist in a more or less perfect condition, according to
the depth and nature of the soil in which they have been pre-
served. Those that are found on, or near the surface of the
.country are generally white, having the surface much oxidised,
while those found more deeply in compact mould are fresh in
colour, and but little changed in appearance from the freshly
broken flint ; and those specimens, obtained from peat, appear
as fresh as if but fractured yesterday.

Some few years since Mr. Whitley reported that flaked flints

o 2

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POPULAR SCIENCE REVIEW.

were to be found abundantly in the surface soil at Baggy Point,
near Croyde, on the north of Devon, as well as along the coast.

The assertion by archaeologists that these flint flakes are the
result of human labour, either, as in the more perfectly adapted
forms, of design, or as the waste material left in the effort to
produce those forms, has given an interest and importance to
them, as the only means left to us by which we may interpret
the unwritten record of the early inhabitants of these islands.
It is, therefore, with the hope of throwing some light on the
subject, in its relation to the early history of the people, that the
connection of these flint flakes with the geological conditions of
the soil in which they are found, is here brought forward.

Near the small village of Croyde, at a place called Baggy
Point, the flint flakes appear to be abundantly spread over the
face of the hills and cultivated fields of the district.

Here, borderiog on the sea shore, at the entrance to a little
vale, through which a small stream of fresh water runs, these
flints appear to have collected in considerable quantities.

The soil in which they are deposited is evidently the accumu-
lation of the superficial soil of the hill, having been gradually
brought into the valley, and possibly with it some few of the
more superficially deposited flakes ; but if so, they could not
have been borne from afar, or they would exhibit signs of
having been rolled or worn smooth by friction, of which there
is not the slightest evidence.

Interspersed with these flints have been found other stones
and evidences of the most primitive kind of human industry.
These mostly exist in the form of smoothly-rounded pebble
stones, evidently brought from the sea beach beneath, and
which, from their pitted and polished condition, afford evidence
of having been used as hammers and whetstones.

Two or three fragments of pottery have been found by Mr.
Hall, and one by Mr. Whitley, that the latter believes to be the
remains of the same utensil which Mr. Hall describes ( Intel-
lectual Observer , December, 1865, p. 355), as being “just
sufficient to identify as having originally belonged to an urn, or
some vessel of similar shape, which, when perfect, must have
been 8^ inches in diameter. One of the portions contains a
small projection, evidently intended to serve as a handle. Bits
of quartz have been worked up with the clay, so as to give
it greater consistency. It is fashioned rudely by the hand, sun
baked, and totally destitute of any attempt at ornamentation,”
The specimen procured by Mr. Whitley, and which now lies
before me, according to my own judgment, has the appearance
of being fire baked, and the presence of the bits of quartz seems
to be accounted for only from the supposition of the manufac-
turers being too ignorant, or too indolent, to remove such great

j

Plate IX

Flint flake s . Devon & Cornwall.

V/West Litir1'

I

FLINT FLAKES OF DEVON AND CORNWALL.

171

sources of weakness to the vessel. Further evidence of fire is
apparent in the presence of small fragments of charcoal, as also
in that of numerous specimens of flint flakes, that have evidently
been under the action of fire. A portion of a long bone, that is,
by all anatomists who have seen it, believed to be human, being
a portion of the tibia, assists, with the preceding recorded facts,
severally to afford presumptive evidence that the spot on which
they were found is in the neighbourhood where a colony of per-
sons, the manufacturers of these implements, existed.

I have said that it is the site of the manufactory of these
flakes, from the circumstance that with those that can be
pronounced useful as knives, scrapers, awls, or arrow-heads,
there are a large number of flakes and chipped flints that can
only be the waste fragments struck off in the process of their
manufacture, together with numerous fractured nodules of flint
from which evidently smaller specimens have been broken,
being the cores from which the knives and arrow-heads were
made. These cores are tolerably abundant, according to my
own observation, and, with that of Mr. Hall, as at 144 to 1,000
of the other flint specimens. The study of a great number of
these cores shows that they invariably have a portion of one
extremity first struck off, and at this flattened extremity the
percussion is given that fractures off the several fragments,
until a prominent angle is produced, which, upon being struck
off, yields a flake that is broad at the base, and as the force ©f
the blow dies out, the fracture thins out towards the opposite
extremity into a sharp point, coinciding with the angle or corner
of the core from which the flake is broken. Other shapes, such
as scrapers and knives, are made, frequently the result of
accident, but, no doubt, in practised hands, the effort of well-
designed skill.

It is probably to many a matter of doubt how such arrow-
heads could have been made with such rude implements, as the
hammer stones that have been found with them must have been.
Undoubtedly, to us, who require iron to be converted into steel
before it is available for use in the construction of tools, it may
be a source of wonder how these things were done ; but a little
experience will demonstrate that, while the fracture of a piece
of flint into any given shape, with rounded stones and blunt
hammers, is difficult, yet, with a tolerably sharp implement of
fractured flint with a somewhat cutting edge, the thing is not
only practicable, but easily fulfilled.

Mr. Whitley and Mr. Hall, who have recorded their opinions
on the flint flakes of Baggy Point, state that et flint is not found
naturally in that part of North Devon, as there is no chalk
nearer than seventy miles, and greensand, with flint, occurs
only in two fields at Orleigh Court, in the parish of Buckland

172

POPULAR SCIENCE REVIEW.

Brewer, distant from Baggy Point thirteen miles in a direct
line, of which four are across Barnstaple Bay. Supposing, then,
a manufactory of weapons existed at Baggy, it is evident that
the raw material necessary for the formation of the tools must
have been brought either by sea or land a considerable distance
for that purpose.”

Further on, I shall, I think, be able to show that the writers
of this remark have overlooked, probably, the true source from
which the natives obtained the raw material, and which is much
closer at hand than these observers have believed. But, sup-
posing that should not be the case, we have parallel instances in
recent savage life. Mr. John Keast Lord, in his delightful
book, The Naturalist in British Columbia, says, <£I found,
in rambling over the sandy plain near Fort Walla-Walla,
numbers of flint implements, together with heaps of fragments.
At some remote period of time, not easy to discover, the Indians
evidently made their arrow-heads and other implements of flint
at this place. The stone of which they were made could not
have been obtained nearer than the Cascades ” (a distance of 150
miles), “and must have been either traded from the Indians
inhabiting that district, or brought from there themselves.

“ I am,” he continues, “ disposed to think a regular flint trade
was carried on by these inland tribes, at some remote period,
with the tribes living on the seaboard and lower parts of Co-
lumbia. Not only were the flints traded, but dentalia (tooth
shells), mother-of-pearl, and the barnacle parasite of the whale.
I dug ornaments, made from the three marine productions
from out a gravel bank, together with a skull, (which had not
been altered by pressure during infancy,) in an Indian burial-
ground, and a number of arrow-heads, fragments, and scrapers,
made from flint or other hard material, which must have been
brought a very long distance, as it has no representative in any
rock found in the immediate neighbourhood.”

We therefore can see no difficulty, in consequence of the dis-
tance of the raw material, for believing this to have been the
focus of the manufacture of the large number of flakes that lie
scattered within an area of at least twenty miles’ diameter, since
similar flints to those found at Baggy Point may be met with,
in considerable numbers, on the adjoining hill, where the plough
lias never been, but where the soil has been washed by many
storms from the surface of the rock. More sparsely they are
to be found on the opposite hill, and along the coast to beyond
Croyde Bay ; also inland on the cultivated districts. And Mr.
Whitley writes to me, to say that he has met with them at Bar-
tridge, ten miles up the Taw valley. He says that, making a
new road, nearly half a mile long, up the hill side, the flakes
were found sparingly all the way ; about 400 pieces of split flint

FLINT FLAKES OF DEVON AND CORNWALL.

173

were found, 100 of which were typical flakes, some being as long
as a finger.”

The soil in the chief place of excavation, that is, in the Dell
near Baggy Point, is about eight or ten feet above the natural
slate rock of the country. The lower portion of the bed consists
of yellowish clay, and the upper part of alluvial or surface soil
brought down by atmospheric influences from the adjoining hill.
A few inches above the clay a line of black mould existed, and
it was in and above this line that all the flints and materials
were found, that is within four feet of the surface, allowing six
inches for soil that had been removed for farming purposes.

Along the coast from Baggy Point to Braunton Burrows a
belt of sandy rock exists, soft in its structure towards the upper
part, but hard as granite in the lower beds. This belt of sand
has been pronounced to be a raised sea beach by Sir Roderick
Murchisson and Professor Sedgwick, who, moreover, pronounced
it to be one of the finest specimens of the kind. Oyer this, so-
called, raised sea beach the surface soil has accumulated, and
in this soil the flint flakes are found. Passing onward, we come
to a tract of two or more miles of blownsand, which is sepa-
rated from the sea by a broad and navigable river, the estuary
of the Taw and the Torridge, from a low grassy place that
stands at a level with high spring tides, and which is separated
from the sea by a broad ridge of large pebbles, that rise to a
height of about sixteen or twenty feet, and extend in length for
about a mile and a half. Outside this pebble ridge, an exten-
sive beach of fine sand covers the surface as far as low water
mark at ordinary tides, beneath the sand, which at different
places may be seen peeping through, is a bed of blue clay about
six feet thick, beneath which is a layer of pebble boulders, simi-
lar in appearance to those which form the pebble ridge ; and
below these exist the angular fragments formed by the natural
disintegration of the slate rock of the country.

In the bed of clay beneath the sand, the roots and trunks of
trees testify to the former presence of vegetable growth, of which
the kinds may be interpreted by the presence of acorns and
nuts found in the clay ; and the growth and luxuriance may be
supposed from the quantity of the fruit, the size and remains
both of the roots and the trunks, as well as from the circum-
stance that perforation in the nuts demonstrate that squirrels
skipped among the branches of the trees that grew there. In
this clay, in which roots, nuts, and acorns exist, flint flakes have
been found in considerable numbers, one or two of which bear
the impress of having been under the action of fire. Thus we
see, in this place, that the flint flakes exist in connection with a
submerged forest, whereas at Croyde and Baggy Point, at a dis-
tance of about four miles to the eastward, they have been found

174

POPULAR SCIENCE REVIEW.

in soil that overlies a deposit that has been, by our ablest geolo-
gists, pronounced to be a raised sea-beach.

The latest alteration of land upon this southern and western
portion of the island, has been pronounced to be one of depres-
sion, and that the latest preceding that movement was one of
upheaving. The former is shown in the numerous submerged
forests around our western and southern coasts, and the latter
is demonstrated in the remains of extensive sea-beaches that
exist all round our shores.

It, therefore, would appear, that a careful study of the geolo-
gical history of these formations, with which, in this locality,
the flints are in connection, will assist materially towards our
arrival at, at least, an approximation to the period at which the
flints were deposited.

The first important study will be the careful analytical examina-
tion of the so-called raised sea-beach. This, as I have before said,
exists between Baggy Point and Braunton Burrows, a distance
of more than two miles, and rises from the present sea level to
the height of about fifty feet. In some places, where the wash
of the sea has been greatest, it is only to be met with in patches.
This destruction has been carried to so great an extent near the
spot where the flint flakes are most numerous, that a small high
water island stands several yards off from the main land, the
intervening ground having been washed away by the sea.
Whereas, on the western side of Croyde Bay, it exists as a per-
pendicular wall stretching a mile along the coast. This so-called
raised sea-beach consists of fine sand mixed with a few shells
and pebbles towards the lower portion, the general aspect
being a series of horizontal layers ; while a closer inspection
shows that these horizontal layers are built up by numerous thin
strata exhibiting lines of false bedding in various directions. In
the upper beds the stone is soft and friable, while in the lower
it is hard and firmly cemented together, so that it is not easily
broken by the geologist’s hammer. In the upper layers the
sand is generally free from extraneous objects, but towards the
bottom a few shells and numerous pebbles of several kinds are
found ; the shells, as far as my own experience goes, consist
invariably of single valves, of mytilus edulis , the common
mussel, to which, upon the authority of Professor Sedgwick
and Sir Roderick Murchisson, those of cardium edule, the
common cockle, patella vulgaris, the common limpet, solen , or
razor shell, and donax truncatulus, of which list only three, the
cockle, razor shell, and donax, can live where sand exists, and
these most probably, as previously observed, are represented
only by the remains of dead valves.

The pebbles are found in the lower stratifications, the largest
specimens being in the lowest, while a little higher, smaller spe-

FLINT FLAKES OF DEVON AND CORNWALL.

175

cimens are found. These, as far as our observations support us,
consist of rolled fragments of granite, quartz, trap, basalt, and
unbroken nodules of flint ; in fact, of materials very similar to
those that exist near high water mark on the present beach, and
which, probably, are obtained from the destruction of the so-
called raised beach that overhangs them.

It was from the flints found on this beach, that were washed
out of the ancient soft sandy rock, that I believe the old inha-
bitants at Baggy Point obtained the fraw material’ from which
the flint flakes were fabricated, and which also probably accounts
for the site of the chief place of manufacture being on the sea cliff.

In one place, resting on the present, and immediately sup-
porting the ancient beach, is a large boulder-mass of granite,
estimated to weigh about twelve tons. The upper portion, that
is, all that can be seen, is smooth and rounded, in a manner that
suggests the whole of it to be similarly water-worn; a circum-
stance that corroborates the opinion of Mr. Williams, in a paper
published as a supplement to that of Professor Sedgwick and
Sir Roderick Murchisson, in the Transactions of the Geological
Society for 1839, that it has been borne from a great distance,
probably by some iceberg, in the great glacial epoch. This
granite boulder contains veins and crystals of red felspar, and
is stated by Mr. Williams not to resemble the granite either of
Dartmoor or Lundy Island, and that there is none like it nearer
than Aberdeen. But this assertion must be received with cau-
tion, as I have recently been informed by Dr. Trefry, of Fowey,
that every kind of granite is found in his quarries in Cornwall,
and I have seen in his porphery hall at Place House, specimens
very similar to that of the boulder in Barnstaple Bay. There-
fore, it appears, that we need not go so far as Scotland to find
the site from which this great stray rock may have been derived;
but still we must acknowledge that it must have travelled from
afar to have been worn so smooth, and that some enormous
transporting power must have been required to bring this gra-
nite mass, even from the nearest granite district, to the place
where it now rests.*

Not being a geologist, I cannot pronounce upon the period to
which the boulder belonged, but of this there can be no doubt,
that it was lodged in its present position before the deposit that
is called a raised sea beach commenced ; therefore, it is older
than the sand bed that rests upon it. The elevation of the
highest point of the raised beach is about forty feet ; we must,
therefore, suppose that the highest point of this beach must
have been covered by water, at least at high tide, before the

* The presence of basalt found among the pebbles is suggestive of the
North of Ireland.

176

POPULAR SCIENCE REVIEW.

elevation of the mass commenced. Forty or fifty feet being the
greatest depth of the structure, it must necessarily follow, that
the lowest portions of the stratified sand bed must have been
from three to four fathoms below the level of the lowest tides.
Now, if we examine the so-called raised beach, where it rests
upon the slate rocks of the present beach, we shall find that
specimens of the common acorn shell, the shore barnacle, Bala-
nus bcclanoides , remain in abundance attached to the rocks,
immediately covered by and . embedded in the sandy deposit
that is called the raised beach, the deposition of which probably
killed them. Therefore, when the sand was first thrown on
them, they must have been several fathoms under water. But
we know that the species of Bcdanus that we find here cannot
live in such deep water, that its normal habitat is a belt on our
rocky shores, between half tide and high water; it is, therefore,
evident, that the present beach must have been at or near its
present level when these Balani were living ; that is, that they
were in the same position as they are now with respect to the level
of the sea and land when the sand was first deposited on them ;
consequently, no evidence that any elevation of the coast line
has taken place since the so-called raised beach, was formed, has
been proved.

To demonstrate what a thing is not may be comparatively
easy compared to that of showing what it really is. In this
instance, the evidence at our disposal may not be quite so
conclusive in the latter as in the former point, but that which
exists appears to be tolerably demonstrative.

The lowest stratifications alone contain pebbles, and these are
all rolled and water-worn, and are such as may be frequently
found belting a sandy shore at or above high water wash. Above
these lines or pebbles the structure of the beds is that of fine
comminuted sand, without admixture of foreign bodies. A stray
valve of the mussel, and, according to Professor Sedgwick and
Sir Eoderick Murchisson, of the limpet and cockle, also may
occasionally be met with ; but these our experience has shown
to have been deposited as dead valves, a fact that is de-
monstrated from the circumstances — first, that the mussel and
limpet do not live in sandy shores ; and secondly, that all the
fragments of the bivalve shells have the concave surface of the
shell turned downwards ; as also all the specimens are those of
one valve only.

The stratification of the beds themselves is such as corre-
sponds with no sedentary deposit. False bedding is persistent
in every part, and takes peculiar forms — sometimes those of
semicircles and short oblique lines, often in opposite directions,
in the same place, in close proximity, assimilating to lines of
cleavage.

FLINT FLAKES OF DETON AND CORNWALL.

177

The upper portions of the beds are soft and friable, the lower
is hard' and petrous, occasioned, I believe, by the action of the
sea water decomposing a portion of the calcareous material, and
cementing the whole into a solid mass ; and all the phenomena
of the entire mass conduces to the conviction, that the so-called
raised beach is, in reality, the undisturbed remnant of an exten-
sive district of wind-borne sand, similar to that which now Exists
on Braunton Burrows and in Croyde Bay, that formerly extended,
most probably, to Baggy Point, reaching some way out towards
the sea. Of this latter hypothesis we have evidence in the por-
tions that remain hardened into stone, that still exist, capping
the summits of the rocks on the beach to the extent of some
two hundred yards seaward. Moreover, a study of the stratifi-
cation of the hills of drifted sand, demonstrates a series of
layers that assimilate to the various modes of stratification
formed in the ancient bed, and which, I think, can be accounted
for by no other means than the varying and ever-changing
direction of the currents of the wind, that builds, destroys, and
restores again, still ever adding to the heap. I would also draw
attention to the circumstance that, in Croyde Bay, some of the
lower layers of the present sand heaps are as hard as rock, and
are probably, though part of the present sand beds, also co-ex-
istent, in point of age, with that which has been misinterpreted
as an ancient sea beach.”

The circumstance that all the flints that are found in the sand
deposit are entire nodules, while those that are found in the soil
that overlies it are fractured flints, demonstrates, I think, that
the latter may have been produced from the former, and that
the sand bed has been deposited since the existing beach has
been at its present level ; that the flints are more recent than
the latest elevation of land upon the coast, that is, that the
sand bed itself has been deposited since the date of the raised
sea beaches around our coast ; and that the flint flakes found in
the surface soil were deposited after the deposition of the sand
bed, a circumstance that must place a considerable period
between the dates of the epoch of the raised sea beaches and
that of the time when the flint flakes were deposited.

The next question that arises is, whether or not, since the
flints have been found in the submerged forest at Northam
Burrows, they may have been deposited prior to the latest
depression of the land upon the coast. To determine this point,
it will be necessary to analyse carefully the geological conditions
of the deposits that exist in connection with the flint flakes
there found.

The Northam Burrows form a large, grassy plain, that exists
at the level of spring tide, high water. The Burrows are sepa-
rated from the beach by an extensive pebble ridge, that affords

178

POPULAR, SCIENCE REVIEW.

a strong barrier to the destructive force of the sea. The origin
of this pebble ridge has not, by geologists, been determined ;
but I think the suggestion is most correct that supposes it to
be the result of the wash of the sea removing the beds of
clay that overlie a layer of pebbles. This pebble bed we have,
by excavations made in several places through the clay, been
able 'to trace within a short distance of the pebble ridge ;
and a recent boring, made for the purpose of obtaining water,
has shown that, in diminished size, the pebbles exist as far up
the sides of the shore as the stables of the Westward Ho ! Hotel.
I think, therefore, that there can be little doubt but that the
terrible wash of the Atlantic thins off the clay, and so exposes
the pebble bed below to the action of the sea, which, by degrees,
carries pebble after pebble to add to the wall that protects the
grassy Burrows from the destructive lash of the waves.

That the Great Pebble Eidge is moving inwards appears to be
ascertained, but the rate of progress has not, I believe, been
determined. But the gradual movement inwards of the Eidge,
however fast or slow, exposes all the shore that is seaward of its
protection to the destructive agency of the waves ; it is to this,
and not to any variation in level of the coast line, that, I believe,
the submergence of the forest along the shore at Northam
Burrows is due. The beach, to a very great extent, is covered
by sand, which, to a large degree, protects the underlying clay
from destruction ; but that the sand is of comparatively recent
deposition is demonstrated in the quantities of the shells of the
Pholas dactylis that are found in the clay beneath, which must
have lived, and burrowed their holes after the clay had been
exposed to the action of the sea, and before the time that the
sand was deposited on the beach ; from the presence of which
the beach is still free for a considerable distance above low
water mark.

The fact, then, that the beach at the shore extremity is
scarcely below the level of the Burrows, while the strata of
which it is composed gradually thin out as it approximates
towards the low water line demonstrates clearly, I think, that
the submergence of the old forest bed is due to the removal of
the superficial layer, and the encroachment of the sea, and not
to the subsidence of the land with respect to the level of the
sea.

Of course, these remarks refer only to the submerged forest at
Northam. But there appears to me to be some reason for a re-
consideration of the subject, whether a subsidence of land around
our southern seaboard has taken place or not. The submerged
forests on our coasts are numerous, and lands corresponding
with these have existed within the period of history or tradition,
and in some places, as in Torbay and Penzance, within the

FLINT FLAKES OF DEVON AND CORNWALL.

179

memory of the present generation. These have disappeared,
and the sea flows over them some fathoms deep, and yet we
know of no alteration in the respective levels of land and water
along the rocky portions of the coast, or other change by which
we might recognise any subsidence of the land.

At the period of the general elevation that raised the ancient
sea beaches to the height of thirty feet above the present sea
level, the sea bottom around our coasts must have shallowed to
the extent of four or five fathoms, an elevation that must have
brought a large portion above the height of the highest tide.
It is the old sea bottom, which, in favourable spots, became
arboreal and fertile, that has continued to resist the destructive
wash of the sea in the shelter of our creeks and bays until the
period of man, that we see in the submerged forests around our
coasts ; and, therefore, as I before observed, if not in all places,
certainly in Barnstaple Bay the encroachment of the sea is due
to the destruction of the superficial soil of the district, and not
to the subsidence of the land.

Assuming this to be true, of which I retain no doubt, it
follows that the flints found in the clay must have been depo-
sited since the latest downward movement, if any such has ever
occurred upon our Devonshire and Cornish coasts, of which the
submerged forests are supposed to afford evidence.

The next point of enquiry that suggests itself, is the relation
that exists between the flint flakes found at Northam and at
Croyde with those that lie scattered over the Western promon-
tory. The places at which they have been found throughout
Devon and Cornwall are sufficiently numerous to induce one to
believe that they may be found to exist universally throughout
the two counties. Around Barnstaple, in an area of twenty
miles’ diameter, they appear to be abundant. They have been
found at Hartland Point; in some considerable numbers, on
the moorland round Dosmare pool ; at the Stepper Point, near
Padstow ; in the Scilly Isles ; in the neighbourhood of Penzance,
Mr. Buffer describes them as scattered over the surface, from
St. Just to Tol-Pedn-Penwith ; on Crusa Down, in the Lizard
district; on the Plymouth Hoe, in the peat at Shaw Bridge,
as well as at Princestown, where some beautifully worked speci-
mens have been found with others, by the prisoners, on the
surface of the gravelly soil, over which had accumulated about
six feet of peat ; at Cornwood, on the moorland ; and on Wind-
mill Hill, near Brixham. In all these localities they lie in
the surface soil of the country; and, as far as there is evidence
to show, must have belonged to the same common sera.

They have also been found in a basin on the top of the Maen
rock in the parish of Constantine, near Falmouth. All these
appear to me to differ from some that I obtained from an

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POPULAR SCIENCE REVIEW.

ancient barrow near Trevose Head, only in the circumstance
that those found in the barrow are of less artistic forms than the
others.

In order to approximate the relations that the flints of this
barrow hold to those that have been found at Croyde, and else-
where in the surface soil, it is desirable that we should give
attention to the circumstances under which they were found,
and the materials with which they were in connection.

In the barrow to which reference has been made at Trevose,
with the flints were found burnt human bones, enclosed within
a coarse clay pot.

Within a few yards of this barrow there existed until very
recently — some remains of which may still be found along the
shore — an ancient shell bed, formed by the accumulation of the
waste thrown away by the ancient people who resided there. In
making an exploration of this Kitchen-midding, along with the
shells of the mussel, limpet, and horse whelk, were found large
quantities of the bones of the roebuck and sheep, stone hammers
such as were found at Croyde, being rounded pebbles brought
from the adjoining beach, together with specimens of pottery of
different qualities, the coarsest of which cannot be distinguished
from that found in the neighbouring barrow.

How, if we turn our attention to the discovery at Croyde, we
find that both Mr. Whitley and Mr. Hall obtained specimens of
coarse pottery as well as beach stone hammers, both of which
closely approximate in character and appearance to those that
were found in the barrow and the kitchen midding, in Constan-
tine Bay. In either case the pottery assimilates in appearance
with that of the clay found in close proximity, and is of a
quality that will bear comparison with the present bricks of
the country.

I think that we are justified in arguing that a uniformity of
material, when combined with a uniformity of design, and appli-
cation of material, existing under similar geological conditions,
is suggestive of an approximation in time. Thus the pottery
found at Baggy Point assimilates nearly to that found both in the
Kitchen-midding and the barrow at Trevose, so also the character
of the stone hammers from the Kitchen-midding resemble those
found* with the flints at Baggy Point; whereas the flint flakes found
in the grave of the ancient chief are far less capable of adaptation
as implements than the best formed of those that have been
found at Croyde, Dosmare pool, the Lizard, and elsewhere, and
thus I think that we are not stretching the probabilities beyond
fair reasoning when we suggest that the flint flakes of Devon
and Cornwall are of the same age as those found in barrows
containing cremated human bones.

But it must strike the observer as peculiar, that the flint

FLINT FLAKES OF DEVON AND CORNWALL.

181

flakes that some archaeologists pronounce as being of the most
primitive form of human implement, are found in such abund-
ance in the subsoil of the western promontory, while the more
perfect flint tools, such as have been found at St. Achieul, Abbe-
ville, Hoxne, and in the drifts and caves of Europe ; thus placing
the more complex and perfected structure at a date, geologically
speaking, far more early than the simple flake, a fact that is
scarcely consistent with the latter being the earlier or more
primitive form of the two.

In this point, it appears to me that those archaeologists are at
fault. My reason for so thinking is, that we find flakes, such as
those found in Devon and Cornwall, still in present use by the
native tribes of Western America ; while I am not aware that
the most degraded race is so far imperfect in skill, at present,
as to use flint implements of the Abbeville type. The reason
appears to me to be simply this, that the flint flakes represent
parts only of more perfect tools, some being the heads of arrows,
others being imbedded in wood so as to represent knives or
crude saws, others being the armour of small javelins, and so on.

To suppose any of them as being arrow-heads is to assume
that they were used in connection with a stringed bow,* an
implement that evidently required a higher degree of thought
to invent than either the hatchet or spear. Now, as arrows were
in use, and retained as instruments of chase and war until
a late period in this country, it must be tolerably certain that
flint was retained, owing to the scarcity of metal, until long
after the use of iron was known. In a Fougou, or subterranean
artificial cave, recently explored by the Natural History Society
of Penzance, in one of the galleries was found a flaked flint
implement alongside of an iron spear-head (?) and some pottery.

Some observers have questioned the adaptation of these sharp
flints as having been designed for the points of arrows, because
they are the result of single blows in their separation from the
core, and bear no evidence of having been afterwards touched to
render them more perfect ; while we find in some places flint

* Mr. J. K. Lord, in his Naturalist in British Columbia , says : 11 The
Indian how is a masterpiece of skilful manufacture ; its elasticity does not
in any way depend on the wood used in its construction, hut on the elastic
ligament procured from the fore leg of the elk ; this is affixed to the
wooden frame-work of the how by a kind of glue made from the skin of
the 1 white ’ salmon, a glue when hardened, resisting the influence of wet
to redissolve it. This elastic hack to the wood acts as would an india-ruhher
hand ; the how when hent takes an arrow about a yard in length, which it
propels with a force equal, for a short range, to that of a rifle hullet. When
an Indian shoots, five or six arrows are held in the left hand, and as the
string, which is made of tendon, is hauled hack, the right hand brings with
it an arrow ; this one is fired, another is seized, and as rapidly as one could
reasonably count, the six arrows held in the left hand are discharged.” —
Vol. II. p. 252.

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POPULAR SCIENCE REVIEW.

arrow-heads beautifully formed, with the barbs perfect, showing
the manipulation of the manufacture. The ability displayed in
the manipulation is evidence of skill in workmanship and of time
required in the execution. But we are not to suppose that the
highly wrought and skilfully laboured flint tool was one that
was less prized than the expensively finished weapon of modern
times, and therefore valued by the chief, the skilful warrior,
or huntsman, as an ornament to his quiver or belt. An
instance of this kind was told to me by Mr. Lord, the naturalist
who accompanied the commissioners who defined the line of
boundary between Canada and the United States, he found
great difficulty in purchasing, from an Indian Chief, a flint
dagger that he wore at his belt, and which had been retained as
an heir loom through several generations, the value of which
appeared to lie in its ornamental character.

In time of war between rival tribes, or in the excitement of
the chase, it is not to be supposed that the highly- wrought and
valued weapon, such as shown in Figs. 1 and 2, would often be shot
awray in the dense forest, or over the marsh, or any place where
the chance of recovery was less than certain. For ordinary
purposes the easiest made would supply the greatest quantity
in the shortest amount of time, and therefore be the most in
demand and most extensively used.

Thus we may assume that the majority of flake arrow-heads
are chance productions, more or less so according to the practice
and skill of the maker ; and the warrior or huntsman selected
from the chips those flakes that he found most readily adapted
to his need, without reference to the original intention of the
manufacturer. Just as Zipporah, Moses’ wife, when in the
Desert, in obedience to her husband made use of a sharp stone,
because it was the best suitable for her purpose at the time.

Becently, while pursuing research in an ancient British burial-
place, in which the Boman feature of civilisation has largely
entered* we found in one grave a human skeleton, together with
two vases, a bronze fibula, some rings, — that from their position
appeared as if they had been worn on the toes, — parts of an arm-
let, a specimen of black flint, a core, from which flakes had evi-
dently been struck. Now, the presence of this core is witness,
that, although bronze and iron were in use, flint was still
valued after the Boman invasion.

It may be thought, that although flint is present in these
graves, yet the character of the materials found with it, as well
as the mode of interment, suggest a considerable separation in
time from the flints found with the pottery in the north of
Devon and Cornwall.

In comparing the pottery of these several places with one
another, those that resembled each other most in character were

Plate X

FLINT FLAXES OF DEVON AND CORNWALL.

183

•of necessity selected, but in the Kitchen-midding in Constantine
Bay there were found specimens of pottery of various degrees
of quality and workmanship, though neither assimilates per-
fectly with that found in the Romano-British grave-yard at
Mount Batten. Yet they approximate so nearly that an ar-
chaeologist would not hesitate to pronounce them, historically
speaking, of a uniform age, produced under different degrees
of civilisation.

In his Commentaries , Caesar tells us that the southern coasts
of this island were inhabited by a different race from the inland
parts ; that central England was inhabited by those who called
themselves natives of the country, dyed their bodies, and wore
the skins of wild animals for clothes ; on the sea coast, but not
extending into Devon and Cornwall, by the Belgic Gfauls, who
were more highly civilised, used iron, and went to war in
chariots, that came thither to plunder and invade the island.
Here we have the element of discord, that must have kept the
southern parts of England in continual ferment, which having
quieted down, when their wars were ended the interlopers
settled, and began to cultivate the land.

It is upon reasoning such as this that I contend there is no
evidence to show, that the flint flakes which we find scattered
over the surface of Devon and Cornwall may not have been co-
eval with the history of the period that immediately preceded
the introduction of Roman civilisation into this country.

DESCRIPTION OF PLATES.

PLATE IX.

Fig. 1. Almond or leaf-shaped flint implement, carefully wrought on
both sides.

„ 2. Flint arrow head, carefully wrought on both sides.

„ 3, 4, 5. Flaked flints. These, as well as the two preceding figures,

of the actual size of the implements which were found under
six feet of peat on Dartmoor.

„ 6. Flint arrow head from a Cromlech on Cam-Brea, Cornwall.

„ 7. Flaked flint from submerged forest at Northam Burrows, Devon.

„ 8, 9, 10, 11. Flaked flints from Baggy Point, N. Devon.

„ 12. Flaked flint wrought upon one side at the margins only. — Baggy
Point.

PLATE X.

„ 13, 14, 15. Flint cores from which flakes have been struck.

,, 16, 17. Fragment of ancient pottery with and without ornamentation,
from a Kitchen-midding in Constantine Bay, Cornwall.

„ 18. Roebuck’s horn, from the same place.

VOL. VI. — NO. XXIII. P

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POPULAR SCIENCE REVIEW.

Fig. 19, 20. Ancient pottery from a British-Roman grave near Plymouth.
A, JB. Diagram of an ancient hed of blown sand in Barnstaple Bay.

1. Present beach.

2. Rocks of do.

3. Granite boulder.

4. Balani on the rocks of the present beach.

5. Sand containing rolled pebbles and shells.

6. Do. do. do. of smaller size.

7 and 8. Layers of irregularly stratified sand.

9. Superficial soil.

C. Diagram of a submerged forest at Northam Burrows.

1. Surface soil.

2. Blue clay.

3. Rolled pebbles.

4. Slate rock.

5. Pebble ridge.

6. Trees of which only roots remain.

7. Sand.

8. High water line. .

9. Low water line.

185

REVIEWS.

M. 13U CHAILLU’S AFRICAN DISCOVERIES.*

A TRAVELLER who writes an account of his explorations, has two serious
difficulties to contend against : if he narrates anything very extraordinary
people are apt to he sceptical as to his love of truth, and if the incidents of
his history approach the commonplace he is not unusually said to he dull.
Unhappily for M. Du Chaillu, his work on u Equatorial Africa ” met with
a good deal of opposition from sceptical naturalists, hut we think that in the
volume he has now given us he has surmounted the obstacles we have re-
ferred to. He does not tell us “a more wonderful tale,” nor is his narra-
tive devoid of interest either to the geographer or the zoologist. The object,
the author tells us, with which he set out upon the expedition, whose re-
sults he has now recorded, was to substantiate the statements which he
made in his first work. He felt hurt by the u unfair and ungenerous
criticisms ” which were passed upon his first work, and he determined, by
supplying himself with an extensive series of scientific apparatus, and re-
turning to Africa, to put his assertions beyond all question. Such were
the author’s intentions on setting out a second time to explore that portion
of Africa which lies immediately below the equator. M. Du Chaillu
thought that, by ascertaining with astronomical exactitude the posi-
tion of the several points visited by him in his travels, he should thus
prevent any of those insinuations with which he was so abundantly assailed
on his first appearance as an African explorer. This was why he took with
him upon his last voyage a number of philosophical instruments, for es-
timating the height, temperature, longitude, &c., of each portion of the
country which he visited. It is to be regretted, therefore, that his antici-
pations in regard to the employment of these implements of research were
not fully carried out. In his first disembarkation his boat was upset, and
those of his astronomical instruments which were not lost were rendered
quite unfit for scientific use through the corrosive action of the salt water.

It is not our aim to follow M. Du Chaillu in his various wanderings from
the moment he left the coast till he arrived in the land of the Ashangui.
In the portion of his book especially devoted to the record of his progress
from day to day among the natives, M. Du Chaillu does not provide a more
interesting literary bill of fare than other writers on African travel. There
are the same endless disputes with the natives, and the old trick of cultivat-
ing diplomatic relations with hoary chieftains, through the assistance of a

* “ A Journey to Ashango Land, and further Penetration into Equatorial
Africa.” By Paul P. Du Chaillu. London : Murray. 1867.

P 2

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POPULAR SCIENCE REVIEW.

quantity of beads or a bright cotton umbrella. In one page we are told
of some prince with an unpronounceable name, and an equivocal code of
morals, who kindly offers to place bis 11 better ” halves at the disposal of the
accomplished white man. In another, we learn how some amorous princess,
with more sentiment than propriety, protects the interests of the traveller.
These incidents are varied by an occasional murder, and the changes are
rung upon what African explorers term a u palaver.” By the way, it would
seem as if the aboriginal tendencies in this direction were contagious to
Europeans, for we seldom find a work on Africa which does not extend
over double the number of pages into which it might reasonably have been
compressed. We do not, however, desire to call our author to account on
this score ; we would merely mention that the great bulk of his volume is
occupied by the ordinary details of a traveller’s diary, and is therefore of
little importance to the scientific reader. It must, however, be admitted, to
M. Du Chaillu’s credit, that his book contains a good deal of matter highly
interesting to the zoologist and the student of ethnology. We shall pre-
sently quote passages in proof of this, but in doing so we may mention that
many of the facts recorded in his former work, and so strenuously denied by
some of our leading naturalists, have been corroborated by the author’s
later inquiries. Concerning these we may especially refer to the contro-
versies on the character and habits of the gorilla, and the Potamogale velox.
These discussions may now be looked upon as closed, at least for the present.
Most of M. Du Chaillu’s assertions as to the habits, &c., of the gorilla, have
been substantiated by his recent examination of these creatures in their wild
condition, and the investigations of Professor Allman, of Edinburgh, show
that in the affair of the Potamogale the author was correct and his critics
did him an injustice.

There are three points in this volume to which our readers’ attention
should be directed. These are the history of the Obongos or negro dwarfs,
the account of the African ant-hills, and the description of the skulls which
the author brought home with him. It is to Professor Owen’s pen that we
owe the chapter on these latter, a fact which lends a scientific interest to the
work such as might not otherwise attach to it. It seems to us that M. Du
Chaillu might have done something more to investigate the tribe of Obongos
than he seems to have attempted. The Obongos appear to be a most in-
teresting, diminutive race, of an extremely degraded type, and it would have
been of the highest importance to ethnology to have had a careful anato-
mical description of them. They are a tribe of dwarfs, dwelling in huts
of the rudest description, and living upon the results of their hunting
expeditions. They do not seem to be so small— if we may judge from the
author’s measurements — as M. Du Chaillu would have us believe. Indeed,
so far as we can gather from the following description, they are a race closely
allied to the Boschismen of more southern Africa : —

u The colour of these people was of a dirty yellow, much lighter than the
Ashangos who surrounded them, and their eyes had an untameable wildness
about them that struck me as being very remarkable. In their whole ap-
pearance, physique, and colour, they are totally unlike the Ashangos among
whom they live. The Ashangos declare that the Obongos intermarry among
themselves, sistersVith brothers, doing this to keep the families together as
much as possible. " Their foreheads are exceedingly low and narrow, and

REVIEWS.

187

they have prominent cheek bones ; but I did not notice any peculiarity in
tbeir hands or feet, or in the position of the toes, or in the relative length
of their arms to the rest of their bodies; but their legs appeared to be rather
short in proportion to their trunks ; the palms of their hands seemed quite
white. The hair of their heads grows in very short curly tufts. This is the
more remarkable, as the Ashangos and neighbouring tribes have rather long
bushy hair on their heads, which enables them to dress it in various ways.
The young man examined had an unusual quantity of hair also on his legs
and breast, growing in short curly tufts, similar to the hair of the head.”

In his description of the white and other ants, the author displays that
lack of minute observation which nothing but a long experience in the study
of organisms can give. For example, it appears to us that some of the
creatures which he puts along with the white ants (Neuropterous insects)
are genuine Hymenoptera ; and again, his descriptions, save in so far as they
relate to the character of the habitation, and the larger external features of
the insect, are useless as means of zoological diagnosis. Much excuse for
this lies in the circumstance that the author’s specimens were all lost in his
retreat from Monoau Kombo, and therefore that he was obliged to describe
from memory alone the objects he had seen. He describes five or six
different kinds of ant, some of them being unquestionably Termites. His
account of the Mushroom-hived Termes is interesting. Speaking of the
habitation of this species he says : —

“ These singular hives, shaped like gigantic mushrooms, are scattered by
tens of thousands over the prairie of Otando. The top is from twelve to
eighteen inches in diameter, and the column about five inches ; the total
height is from ten to fifteen inches. They are not all uniformly built, but
differ in the roundness or sharpness of their summits. The hive is not so
firmly planted in the ground but that it may be knocked down by a well-
planted kick. When felled, the base of the pillar is found to have rested
on the ground, leaving a circular hollow, in the middle of which is a ball
of earth full of cells, which enters the centre of the base of the pillar, and
the cells are eagerly defended by a multitude of the soldier class of the ants,
which I took to be males, all striving to bite the intruder with their pincer-
like jaws. On breaking open the ball — which, when handled, divided itself
into three parts — I always found it full of young white ants, in different
stages of growth, and also of eggs.”

M. Du Chaillu’s further description of his observations of this ant colony
will prove most attractive reading to lovers of natural history, but the details
are too extensive for introduction into these pages. Professor Owen’s portion
of the present work has some importance, although it establishes no law which
has not already been deduced. He describes, in pure but not simple anato-
mical fashion, three skulls, one being that of a native of Fernand Yaz, and
the two others being those of people of the Fan tribe, that strange group
of cannibal Africans, of which M. Du Chaillu has more than once given an
account. There is one statement of Professor Owen’s which is of consider-
able interest : it relates to the dolicho-cephalic * character of these skulls.
Speaking of this term as applied to the skulls brought over by the author,
he says that it does not imply a “greater length of cranium than in Indian
and European skulls, which would be called brachy-cephalic,t but merely a

* Long-headed.

t Broad-headed.

188

POPULAR SCIENCE REVIEW.

want of filling out of tlie brain-case, by lateral or vertical expansion.” Here
we may remark that the Professor takes the opportunity of saying a word in
favour of bis view that the brain of man is absolutely different from that of
the ape, for in concluding the chapter he writes : —

“ In all the negro-skulls'in the present collection, as in those of Boschis-
men, Mincopies, Australians, and every other variety that has come under
my observation, the essential characters of the archencephalous sub-class,
and of its sole genus and species, are as definitely marked as in the skulls of
the highest white races.”

Altogether we may say of M. Du Chaillu’s work, that it is interesting as
a book of travels, and is instructive in relation to those departments of
science to which the author has given his attention. If we were to be very
critical, we should say that in many instances the style was rough and jerky.
But on the whole the author’s English is readable, and his book is good.
M. Du Chaillu is not an Englishman, and cannot therefore be expected to
distinguish himself in what so many English travellers fail — clear English
composition.

POPULAR BOTANY.*

A WONDERFUL man, indeed, M. Figuier appears to be. There is no
subject which he is not ready to write upon, and we must confess
that his compilations have a certain merit to recommend them. He is in
the department of scientific book-manufacturers, what M. Dumas is in
light literature. He wields a pen which, in the language of the “ liners,”
is eminently “prolific.” Not a year passes by without the appearance of
some three or four large treatises bearing the stamp of M. Figuier’s
factory. His great book on Insects has not yet been translated, but doubt-
less we shall soon have an English edition of it. Meanwhile, we have his
“Vegetable World ” reproduced in our “mother tongue,” and it behoves us
to say a few words about it.

There is hardly any branch of science which is undergoing so little radical
change as botany. That which we were taught ten years ago is that which
students learn to-day. This is at least the case in regard to the purely scientific
divisions of the subject. Of course each day brings forth its list of newly-
discovered plants, and in this way not only adds to the enormous accumula-
tion of specific and generic names, but affords the botanist new facts from
which to discover the natural affinities and the geographical distribution
of the vegetable species. But as regards the physiology t of the plant —
the offices of the various tissues and organs which compose it — there is little
to be added, even in the year 1867, to the grand generalizations put forward
in Schleiden’s “ Treatise,” % published so many years ago. Indeed, we may

* “ The Vegetable World: being a History of Plants, with their Bota-
nical Descriptions and peculiar Properties.” By Louis Figuier. London :
Chapman and Hall. 1867.

t Always excepting the beautiful researches of Mr. Darwin on the subject
of fertilization.

% “ Principles of Scientific Botany, or Botany as an inductive Science.”

REVIEWS.

189

safely affirm that none of tlie works which succeeded that of the Professor
at Jena is in any respect to he compared with it. So likewise as to structure,
if we except the more recent inquiries of Mr. Arthur Gris, M. Chatin, M.
Bomet, and a few others, little has been added to the knowledge acquired
ten years ago. It may he gathered, therefore, that the preparation of a
general work on hotany is attended with no yery insurmountable difficulties.
Hence, as might he expected, M. Figuier’s present work is by no means as
inaccurate as most popular hooks on scientific subjects.

M. Figuier has divided his task into four portions : The organography
and physiology of plants ; the classification of plants ; the natural families of
plants; and geographical distribution. The division is a good one, but is not
novel. Under these four heads M. Figuier discusses the natural history of
plants ; and, by the aid of illustrations — of which it is faint praise to say
that they are admirably conceived and executed — and in a terse clear style,
he certainly does much towards the “popularization” of botany. We
cannot say, however, that the four divisions are equal in point of treatment.
Clearly, the first, which is devoted to the structure and physiology of plants,
ranks first also in order of merit. The portion in which the classification of
plants, and the arrangement into families is given stand next, and the chapter
on distribution is judiciously placed last for more reasons than one. If we
have any fault to find with the classification, it is that in some portions it
is more detailed than is necessary. The arrangement of the natural families
it is impossible to complain much of, for the writings of Lindley have not
been spared in this part of the compilation. The geographical portion of the
subject, however, we must and do protest against; it contains no reference
to important inquiries which have thrown real light on the question of
geographical distribution. Indeed its scientific qualities may be represented
by the word nihil. There is a great deal said about “ the rich and varied
vegetation of Asia,” and so forth ; but, on the whole, this part of the book is
a poor reproduction of the old (l physical geography” of our schools — a
science which contains not a single generalization, and is full of questionable
facts. In describing the organs of plants, M. Figuier has fallen into very few
mistakes, but he has been guilty of some omissions, which the botanical
reader must instantly notice, but which are of little importance to the amateur.
There is only one other matter concerning the author, to which we must
call attention. That is his tendency to become hyper-popular in explaining
certain phenomena. It is one thing to confess one’s ignorance of the nature
of some organic operations, and quite another to assign them to the limbo
of a mysterious agency. We do not therefore justify M. Figuier’s position
in the following assertion : —

“We must, besides, in order to explain the great phenomenon of the life
of plants, bring in a force very superior to all these physical actions. This
is the action of vital force, which God only bestows, and of which He alone
directs the results.”

W e are puzzled to know whether these sentences are more remarkable
for irreverence or bad grammar, but we cannot assent to their science. M.

Translated by Dr. Lankester, F.R.S. A few copies of this work may still
be had of Mr. Hardwicke.

190

POPULAR SCIENCE REVIEW.

Figuier should rather have said : u Beyond this point we are unable to>

explain the process of life in plants \ we may hope that further research will
remove a great deal of our present ignorance, but meantime we must wait ?”
Does M. Figuier mean that life is the only power wielded by the Creator ?
if not, then which does he especially instance, vital force as something which.
“ God only bestows.” Where do the other forces come from P
We have done with the author, and come now to the translator, who
modestly announces himself as W. S. 0. He has no doubt had a
difficult task to perform, and one which none but a translator is able
thoroughly to appreciate ; he has had to preserve the author’s style, while
rendering his meaning clearly intelligible 5 and, in addition, he has had
to convert the Gallic scientific technicalities into English ones — a process
utterly impossible for one unfamiliar with the subject treated upon in the
original. In all cases, therefore, the impartial critic must lean toward the
translator, and our sympathies extend too in this direction. But, making all
allowances, we cannot award very high praise to W. S. 0. for his exertions.
He has certainly given us a good translation of the work of a writer addicted
to occasional indulgence in the u grandiloquent ” and “ ornate,” but he has
many errors to account for, and these we hope to see removed in that second
edition which the book is certain to go through. We need only allude to a
few passages in which we find the rules of composition strangely violated.
They are not special samples, but are typical of a general carelessness of
style which pervades the volume. Thus, u They bear the name of sto mates
from the Greek word oro/jur, ‘ mouth.’ A stomates of Cycas under the
microscope is seen in fig. 126.” “ It must be added, however, that at the
same time that leaves transpire they also reciprocrate and absorb water by
their own surface.” a In every case hitherto mentioned the number of flowers-
of the same generation are indeterminate in each group.” We would ask
the translator also to revise his scientific terms, names of writers, &c. ; many
of them are incorrect, as in the following instances: Uuger, Scaleform,.
Destrin, D. purpusia, tracheii. The objections that we have raised are not
serious ones 5 and when we consider the comprehensiveness, beauty of illus-
tration, typography, and general accuracy of M. Figuier’s work, we are bound
to say of it, that it is a book admirably adapted to the class for which it i&
intended.

ASTRONOMY.* .

TT7E are sorry to be compelled to admit the truth of Mr. Chambers’s asser-
T t tion, that astronomy is not cultivated in this country either as a study
or as a recreation to the extent that it is on the continent of Europe and in
America. We are not, however, prepared quite to consent to his explanation
of the reason. There is no doubt something in the fact that astronomy has
not been correctly popularized as a study, but still this hardly explains the
circumstance. It is true that till of late we have not had a treatise
which might be placed in the hands of those ignorant of mathematics — at

* u Descriptive Astronomy,” by George F. Chambers, F.R.A.S., of the
Inner Temple, Barrister-at-Law. Oxford : at the Clarendon Press. 1867.

REVIEWS.

191

least, such a treatise as would encourage the study of astronomy. But
hooks have been published, which, whatever their shortcomings, ought to
have engendered a love for astronomical pursuits, and we trust that to some
slight extent they have been successful in this respect. May not the rea-
son, or one of the reasons, lie in the supposition that our climate, cloudy
skies, foggy air, and a condition of things productive of discomfort to the
English amateur, is unfavourable to astronomical pursuits ? We merely
ask the question in order that amateurs may be assured that they may
engage to advantage in the study of the heavenly bodies even in this
country. We feel positive that if it were generally known thkt even with
a cheap telescope a patient observer may make most important discoveries,
the field of workers would soon become enlarged. Now this effect we think,
is likely to be achieved by the splendid volume which has been issued by
the Clarendon Press. Mr. Chambers is one whose previous labours in the-
departments of astronomy and meteorology highly qualify him for the task
he has undertaken, and few we think will be disappointed with the work
he has now given us. a Descriptive Astronomy ” is a large book, extending
over nearly 900 pages, and abounding in excellent, and some of them novel,
illustrations. There is hardly any division of his subject which the author
has omitted the discussion of — unless, indeed, that of solar-spectrum-
analysis — and he gives as his reason for this omission that the time has
not yet come for regarding this branch of physics as a section of astronomy.
There is some truth in this, and a good deal of sound sense, for it shows
that the author wishes his treatise to be regarded as solid and accurate
rather than sensational and startling. We wish we had room for a full
analysis of Mr. Chambers’s book, of which we are able to give no more than
the most outlinear notice. We therefore all the more strongly urge our
readers to take it up and examine it for themselves. It deals with the sub-
ject in its entirety. Abstract considerations are as much as possible,
avoided, except where their introduction is absolutely necessary; but all
phenomena are carefully described, and the most recent discoveries find a
record in Mr. Chambers’s pages. The advice to workers is eminently good,,
being simple and practical, and such as the “ intending” astronomer requires.
The history of the science and the mode of construction of the several
apparatus are also given. Finally, there is a well-arranged series of astro-
nomical tables. With one of Browning’s cheap telescopes and a copy of
Mr. Chambers’s “ Descriptive Astronomy,” even the amateur may look
forward to establishing his fame as a student of the heavens.

POPULAR SCIENCE, par excellence.

SIR JOHN HERSCHEL is said to be our best popular scientific writer^
and certainly his volume of lectures bears high testimony to the accu-
racy of the general belief. The lectures, which he has here reprinted, are
certainly the most interesting, instructive, and intelligible essays on scientific

* “Familiar Lectures on Scientific Subjects.” By Sir John F. W. Her-
schel, Bart., K.H. London : Alexander Strahan. 1867.

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POPULAR SCIENCE REVIEW.

questions which it has ever been our good fortune to read. There is a force
of style in them, which bears the reader on, nolens volens, while the methods
of illustration, the well-selected analogies, and the clear description, render
subjects hitherto obscure and difficult, lucid and easily grasped. The
lectures were originally delivered before various local philosophical societies,
and published in some of our literary journals. Some would say, why
reprint them ? We do not. It seems to us that the publisher has shown a
wise discrimination in selecting them for reissue. They are upon several
attractive subjects, and some of them rise so far in value above the merely
popular, that we should like to see them enlarged and published sepa-
rately. We refer especially to the three lectures on light, which extend
over 180 pages of the present volume, and form a masterpiece which is
certainly unrivalled. The other topics which Sir John takes up are — vol-
canoes and earthquakes ; the sun j comets ; the weather and weather-
prophets celestial measurings and weighings ; sensorial vision ; the yard,
the pendulum, and the metre atoms ; the origin of force j the undulatory
theory (this lecture ought to go with the three on light) ; and the estimation of
skill in target-shooting. It is rare to find in combination so much literary
skill, tutorial power, and scientific erudition as this volume presents. It
is no flattery to say of it, that it may be read by the savant with pleasure,
and by the amateur with profit.

ORGANIC CHEMISTRY.*

IN our notices of Parts I. and II. of this work, we were compelled to give the
author unqualified praise for the manner in which he had prepared his
new edition. In this instance, too, we must do as we then did, for in no
respect has the author left anything undone to render the volume on organic
chemistry worthy of his own high reputation, and valuable both to chemical
students and to manufacturing chemists. As a most comprehensive expo-
sition of the theories and phenomena of modern organic chemistry it stands
unmatched, and as a work of reference, not only upon the organic chemistry
of the laboratory, but upon the complex organic chemistry of the manufac-
tory, we know of no work which can equal it. The gas manufacturer, the
dyer, the petroleum distiller, the soap and candle maker, the baker, the
distiller, the wine merchant, will all do well to purchase Dr. Miller’s third
volume ; and the physiologist and educated agriculturist will find in it much
to interest and instruct them. This was true of the older editions, but it is
trebly true of this one, which contains reference to all the results of recent
research. The most striking feature of the volume is the introduction of
the new notation ; this feature may prove a little objectionable to the older
students, but its employment was inevitable. The new notation has esta-
blished its claims to recognition ; it is beginning to be universally employed

* u Elements of Chemistry, Theoretical and Practical.” By William Allen
Miller, M.D., LL.D., &c. Third Edition. Part HE. Organic Chemistry.
London: Longmans. 1867.

EETIEWS.

193

by modern chemists ; it affords many advantages over the old system, and it
is not difficult to master. The “ old school ” reader, too, will be a little
confused at first to find that sulphate of soda is now sodic sulphate , and that
the carbonic acid, so impressed on their minds (not physically), is now be-
come transformed into carbonic anhydride ,• but he will soon get over these
little difficulties, and then, with the help of Dr. Miller’s excellent powers as
a teacher, he will walk over the field of organic chemistry without much
stumbling. This third volume is the best of the three, and the most useful
and suggestive. The physician, the chemist, and the manufacturer will all
find something in its pages touching upon their respective pursuits and
inquiries.

THE WORLD BEFORE THE DELUGE*

ANEW edition of this highly popular 'work has been issued. Need we
say it is not less handsome than the first. When we look at its mul-
titude of illustrations, its luxurious paper, and its good typography, we
must give the publishers every credit for their labours. The next point to
be considered is the matter of the book. In the last edition this was cer-
tainly out of keeping with a good deal that modern geology has taught us.
It is satisfactoiy therefore to find an improvement in this edition, which we
are told was revised by Mr. Bristow. Few abler geologists could have been
selected for the work, and we only wish that full play had been given to him ;
but we fear that he has been sadly trammelled in the execution of his task
of revision. This we conclude from the following passage in the preface : —

“ Many points which are more or less inferential, and therefore matters
of individual opinion , and especially those on which M. Figuier bases his
speculations, Mr. Bristow has left in their original form, rather than make
such modifications as would wholly change the character of the book.”

What this statement means, and how far the abstract proposition it
involves, can be justified, we leave the reader to j udge for himself. For our
own parts we can only say, that while in some ways the book has been
improved (especially by means of the additions made to it) it has been on
the whole very little altered. M. Figuier describes the leading facts and
phenomena of geology very well, and the profuse illustrations remove any
obstacles that might otherwise meet the general reader ; but his speculations
are, in our opinion, very often more visionary than well-founded, and we
must entirely dissent from his mode of restoring pre-diluvial forms. The
pictorial Bible is an admirable book, but we do not see that its noble teach-
ings are more enhanced, or the facts of geology more elucidated, by abstract-
ing its suggestive pictures of the Deluge and the Garden of Eden to illustrate
a treatise on popular geology. The woodcuts intercalated with the text,
are excellent of their kind, and are numerous and well-selected, but the
“ ideal representations” are the badly-executed extravagances of a too-
imaginative genius.

* “ The World before the Deluge.” A new edition. By Louis Figuier.
London : Chapman and Hall. 1867.

194

POPULAR SCIENCE REVIEW.

THE SCIENCE OF HEAT.*

THIS excellent little manual was, through some oversight, left unnoticed in
our last Number. It is clear, well written, and up to the date of modern
discovery, and is so arranged as to he easily mastered by the intelligent
student. The book is divided into three portions : in the first are described
the various effects produced upon bodies by heat ; the second contains the
laws which regulate the distribution of heat through space ; and the third
relates to the nature of heat, its sources and its connection with other pro-
perties of matter. Mr. Stewart is one of our highest authorities on the
subject of heat, and this fact alone should insure the success of his manual ;
but the book carries with it intrinsic elements of success ; for it contains
exactly what the University-student wants, and it is so arranged that the
reader is led to take an interest in the phenomena of heat before being in-
troduced to the complex laws which govern them.

Chemical Philosophy according to Modern Theories , by Dr. Adolphus C.
Wurtz, F.R.S., translated by W. Crookes, F.R.S. London : Dutton. 1867.
We could not possibly review this work in our columns, for it is such an
advanced dissertation upon the modern philosophy of chemistry, that, even
if we had the space at our disposal, the treatment of the subject would be
too technical for our pages. We remember with pleasure seeing the lectures
of Dr. Wurtz published in the Chemical News , and we congratulate the able
editor of that journal upon his selection of the lectures, and on the ability
with which he conducted the translation. The book is small, but it contains
an able exposee of the modern theories ; and we confess, with its translator,
that for breadth of view, lucidity of expression, orderly arrangement of facts,
and shrewdness and fairness in reasoning, Dr. Wurtz’s treatise appears to be
singularly distinguished.

The Inductor ium, or Induction Coil, fyc., by Henry M. Noad, Ph.D., F.R.S.
Second edition. London : Churchill. 1867. We direct notice to this, a
second edition of Dr. Noad’s instructive little work on the induction coil.
Those who are anxious to get an insight without much trouble into the
wonderful phenomena connected with the operation of the induction coil
should purchase this book.

The Year-Book of Facts in Science and Art , by John Timbs, F.S.A.
London: Lockwood. 1867. This little volume is a resume of scientific
progress during the past year. The difficulties of such a compilation render
mistakes inevitable, but Mr. Timbs’s summary is more accurate than its
class generally is. The cuttings are principally from the Illustrated London
Neivs and Mechanics' Magazine.

The Twin Records of Creation , or Geology and Genesis, by Geo. W. Victor
Le Vaux. London : Lockwood. 1867. Adopting the extremely novel

* u Elementary Treatise on Heat.” By Balfour Stewart, LL.D. Oxford :
at the Clarendon Press, 1866.

REVIEWS.

195

and anti-heretical maxim of u Magna est veritas et prevalebit,” Mr. Le Vaux,
whose name we do not remember to have heard before in connection with
science, treats ns to some of the late Hugh Miller’s conclusions. He has
hashed the joint prepared in so savoury a way by the Scotch geologist;
hut it has sadly lost flavour in recooking. Mr. Vaux has a very good object
in view, and those who are anxious to see the records of nature and the
Bible contrasted should read his book. He thinks he may be thought pre-
sumptuous in offering a volume to the public, but the following explanation
will doubtless be received as satisfactory : u From my childhood I have
had a particular taste — indeed, I might say a passion — for the study of
nature, and of geology in particular. The rugged mountain and lonely glen,
the wild cascade and forest glade, have always had peculiar attractions for
me.” The book was originally addressed to some private friends, and as
occasionally does occur in such instances, its merit was appreciated and the
author felt constrained to publish it.

196

SCIENTIFIC SUMMARY.

ASTRONOMY.

mHE Deduction of the Mean Figure of the Farth from comparison of the
-JL Anglo-Gallic, Russian, and Indian Arcs, is the subject of a communi-
cation transmitted to the Philosophical Magazine for February, by Archdeacon
Pratt. The paper is one of the highest importance ; but as the details are
of too mathematical a nature for these pages, we merely call attention to
the fact of the publication of the essay. Those especially interested can
peruse the original memoir themselves.

The Solar Spectrum. — M. Angstrom in a memoir recently published, calls
attention to two important results arrived at from his researches. The first
is the certain presence of manganese in the sun, he having observed the
coincidence of at least thirty lines. The other is the discovery of a new
hydrogen line. The spectrum of hydrogen, presents, as is well known, three
lines — two of which coincide with C and F, and a third with a line near G.
The fourth line which M. Angstrom has observed is near the middle of the
interval between G and H ; it coincides with a very intense solar line, which
he has called h. With Geissler’s tube this line is very distinctly seen,
although it is very much less feeble than the three others. This result is
the more satisfactory, as the line h was the only one among those of a
certain intensity, whose origin still appeared mysterious. The explanation
of it which M. Angstrom has found in the spectrum of hydrogen, acquires
an additional interest from the fact that the line h occurs several times in
the stellar spectra, drawn by Mr. Huggins.

The cause of the Heat of the Sun and Heavenly Bodies. — On March 4, M.
Patau called the attention of the French Academy to his memoir on the
above subject. The memoir, however, has not yet been laid before the
members.

The Solar Spots. — Herr Kirchhoff has published a reply to M. Faye,
relative to the course of the solar spots. He says, whatever be the consti-
tution of the sun, the spots can only be explained by a local diminution of
temperature approaching or exceeding incandescence. “My hypothesis
supposes the cause of this diminution to lie in the radiation of clouds,
toward planetary space, of clouds produced by the condensation and isola-
tion of the photosphere.” Herr Kirchhoff admits that possibly other ex-
planations of the cooling process, may better meet all the facts of the case,
but he considers that the adoption of any of them which rejects the con-
sideration of a diminution of temperature would be equivalent to asserting
the natural law3 are quite different on the sun to what they are on the
surface of the earth. — Comptes Rendus , March 4.

SCIENTIFIC SUMMARY.

197

Disappearance of a Lunar Crater. — Padre Secchi, writing from Rome, on
February 14, states, in relation to tbe reports that the Crater Linne has dis-
appeared, that he has recently had an opportunity of investigating this
point. He says : On the evening of the 10th (February), between 8 and 10
o’clock, the Crater became lighted up, and one could see near the limiting
circle a small point, and around it a very flat irregularly circular crown.
The absence of proper illumination and the promoxity of the moon to
the horizon, prevented further observation. On the 11th, in the evening,
Linne was already pretty well illuminated ; and at 7 o’clock, one could see
distinctly a very small crater, surrounded by a brilliant white crown, which
shone brightly on the deep shade of the Mare serenitatis. The size of the
orifice of the crater was about § of a second or more ; and the crown was a
little larger than Sulpicius Gallus. Signor Secchi dwells upon this com-
parison, because he says it shows us M.M. Moedler and Beer, whose map he
employs, should never have figured a crater so large and well-defined as
they assign to Linne , for a white spot such as that which exists at present ;
in fact Sulpicius Gallus is actually much larger than the little crater which
forms the centre of the spot.

The Meteoric Shower of November in Mexico . — M. A. Poey writes to
M. Elie de Beaumont concerning his observations in Mexico. He states
that there was really no shower perceptible from his observatory. The
following are the results of the inquiries made at the Observatory of Santa-
Clara, by the French Scientific Commission under M. Poey : —

Night of November 13 and 14.

Northern Hemisphere.

Southern Hemisphere.

Total.

From

12 p.m. to 1 a.m. 7 meteors.

12 p.m. to 1 a.m. 11 meteors

. 18

1 a.m. to 2 A.M. 16 „

1 a.m. to 2 A.M. 12 ;,

. 28

Total . .',28

Total . 23

~46

Night of November 14 and 15.

Northern Hemisphere.

Southern Hemisphere.

Total.

From

1 a.m. to 2 a.m. 13 meteors.

1 a.m. to 2 a.m. 17 meteors

. 30

2 A.M. to 3 A.M. 16 „

2 a.m. to 3 a.m. 10 meteors

. 26

Total . . 29

Total . *27

~56

It may be seen from the above figures : (1) That the number of meteors
did not exceed the mean of ordinary nights ; (2) That there were ten millions
more seen on the night of the 14th and 15th, than on the preceding even-
ings ; (3) That the maximum number was seen between one and two.

The probable Periodicity of the Comet observed at the Observatory of Mar-
seilles on January 22. — This has received the consideration of M. Silloujelt.
He has calculated — though with the assistance of very imperfect instruments
— according to Cauchy’s method, the elements of this comet. It results
from his calculation — necessarily approximative — that the comet is periodic.
He has obtained for its elements almost analogous numbers to those figured
under the number 27 in Arago’s Astronomy. This comet, therefore, would
seem to be that which was discovered by Messier, in April 1771.

M. Faye's Theory of the Solar Spots. — The views of Herr Kirchhoff, given
already, have been answered by M. Faye, who maintains that Herr Kirch-

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POPULAR SCIENCE REVIEW.

hoff’s explanation is in no way astronomical, and is unsupported by obser-
vation. In referring to bis own theory of solar reflexion and parallax, he
has confirmed the fact, which passed unnoticed up to the present time, that
when, after the apparition of a beam or fillet of light thrown from one side
do the other, a spot is divided into two parts, one of the halves, as if it had
received an impulse in front, takes an abnormal motion of its own, while the
other half continues alone its normal movement, with variations of velocity
which only depend on the latitude.

The Laws of Isolation. — M. G. Lambert read a paper before the French
Academy on January 28. The memoir referred especially to the tempera-
ture of the Arctic zones, and to the power exerted by the diurnal isolation
■of the sun, the principal cause of this temperature. The power of isolation
in a certain place ought not to be confounded with the thermometric effect
which is its consequence, but which depends upon a number of variable
causes analysed by the author, and of which the technical details have been
sent in an extended memoir upon isothermic lines, &c. Designating by
L the heliocentric longitude of the sun, w = the obliquity of the ecliptic,
w'= the angle formed by the axis of the earth with the circle of isolation,
un angle which is equal to the declination, l = the latitude, we have the
following equations to represent the graphic trace of the curve of isolation
at each parallel and at each season: —

Sin w'— sin w sin L

x — L cos ( l—w ')

y — L cos {l— tv') tan w' Sw ( l—w' )

in which x represents the power of the diurnal isolation.

The French Academy's Prize for Astronomy has been awarded to Mr.
MacLear, for the mensuration, at the Cape of Good Hope, of an arc of the
meridian, and the publication of his great work, a Verification and Extension
of La Caille’s Arc of Meridian at the Cape of Good Hope,” two vols., 4to.
The celestial amplitude of the arc measured by Mr. MacLear differs only by
a small fraction of a second from the amplitude found by La Caille, and this
agreement contributes to maintain the reputation of the French astronomer.

The Cometary Theory of Shooting- stars — to whom does it belong ? — The
Abbe ^Moigno, who has broached this question, and who evidently feels
-strongly on the point, makes the following observations in our contemporary,
the Chemical News, of March 15 : u In a quite recent note inserted on March
3, in the International Bulletin of the Imperial Observatory, and on the 8th
inst. in the Bulletin of the Scientific Association of France, M. Le Verrier
resumes on the cometary theory of shooting stars, and persists in attributing
the honour of it to himself, without condescending to mention the name of
Schiaparelli, whose letters, however, have been published in a journal of
great authority, the Meteorological Bulletin of the College of Borne, issued
under the superintendence of the Bev. P. Secchi, and were translated by the
writer before M. Le Verrier had published a single word of his researches.
We are really frightened by this system of organized cool-blooded appro-
priation, and more so by these lines, the effect of which has been even more
coolly calculated : Sir John Herschel , who, along with his son, Alexander

Herschel , has paid great attention to shooting-stars, gives his complete assent to

SCIENTIFIC SUMMARY.

199-

the theory of the swarms of November. Poor M. Schiaparelli ! Happily
the Astronomische Nachrichten have collected the necessary papers, and he
will soon he in a position of having his revenge.”

The Difference of Longitude between Newfoundland and Valencia has re-
cently been ascertained by means of the Atlantic Telegraph. It has been
effected by Mr. Gould, who was sent to estimate it by the Coast Survey of
the United States. A preliminary calculation gave longitude of Heart’s
Content, Newfoundland, in respect to Valencia, 2h. 51m. 56’5s. Time occu-
pied by the electricity to pass through the cable, 0-32s.

BOTANY.

Distinction of Species among the Algce. — In the last number of the Micro-
scopical Journal there is an able paper upon this subject by Dr. Braxton
Hicks. He continues the controversy with Mr. Archer of the Dublin
Natural History Society. Mr. Archer believes very firmly, that certain
forms, which he and other botanists have described, are distinct species, fixed
and immutable. Dr. Hicks doubts this. He contends that, in order to be
convinced that some of the organisms described by naturalists are undoubted
species, it would be necessary to have a knowledge of the whole develop-
ment-history. This knowledge we do not possess, and since certain of the
temporary conditions of some algae resemble the forms called species there
appears to be much force in Dr. Hicks’s arguments. In his last paper, Mr.
Archer advanced several arguments in support of his opinions, and among
others he adduced the fact of conjugation as the most certain test of the-
fixity of species. He believes this phenomenon to be the analogue of pollen-
impregnation, and therefore considers that it shows the maturity of the
cells in which it occurs. But, in reply, Dr. Hicks asks, looking at the
process itself, have we any direct evidence u that it is anything more
than a direct fusion of the contents of two cells ? Whilst admitting

the value of the analogy, ought we to ascribe more value to the act
than really appears ? What, for instance, is it in Spirogyra ? A process,
of one cell joins with the process of another, and their contents thus being
able to come into contact, fuse into one mass. Before the change began, it
was impossible to perceive any difference between the two cells. Further
than this, we often find in some species that, should no second filament be
near enough, two adjoining cells of the same filament conjugate, by
throwing out processes round the joint which divides them, and then their
contents fuse.” Dr. Hicks philosophically contends that, until we have proved
that no true antheridia exist in Spirogyra, for example, we cannot look upon
conjugation as anything more than a vegetative process, unconnected with
the maturity of the cells in which it occurs.

The Frond-cells of Lemna and Wolffia. — Our readers will remember that
we, some time since, recorded the discovery of a new British species of
Duckweed, by Dr. Henry Trimen. This diagnosis was formed upon the
external characters of the plant. But Professor Gulliver has shown that
microscopic examination of Lemna minor and Wolffia arrhiza shows

YOL. VI. — NO. XXIII. Q

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POPULAR SCIENCE REVIEW.

decided differences of structure between tbe two. The former abounds in
raphides, while in Wolffa there are none.

The Function of Barren Stamens. — Dr. Maxwell M. Masters, in a short
paper recently published, gives a capital account of a plant now at Kew (in
the palm-stove), and which he refers to Dombeya angulata. The most in-
teresting part of the description, however, is that which relates to the barren
stamens of this plant and their functions. Some light, he says, is thrown
on the use of barren stamens by an examination of this plant. In the
fully expanded flower the upper angle or point of each petal is about on a
level with the stigma and the lip of the barren stamen, the outer flat surface
of which latter, as well as the adjacent portion of the petal, are often dusted
over with pollen, the two stamens, nevertheless, being a considerable dis-
tance beneath these organs. In less fully developed flowers, the barren
stamens may be seen curving downwards and outwards, so as to come in
contact with the shorter fertile stamens, whose anthers open outwardly, and
thus allow their contents to adhere to the barren stamens. These latter,
provided with their freight of pollen, uncoil themselves, assume more or
less of an erect position, and thus bring their points on a level with the
stigma, whose curling lobes twist round them and receive the pollen from
them. “ The use, then, of the long staminodes seems to be to convey pollen
from the short fertile stamens to the stigma, which, but for their interven-
tion, could not be influenced by it.” Yide The Journal of Botany, March.

Is Calluna Atlantica a Neiv Species ? — This question is answered in the
negative by Professor Asa Gray. In a recent communication, he says that an
examination of specimens from Cape Breton, Nova Scotia, and New Eng-
land, does not reveal the naked pedicels, broader sepals, and “tip of flower-
ing branches, not continued into a leafy shoot while the flower lasts.”
These, it will be remembered, were the features on which the foundation
of the new species was based. Yide Silliman’s American Journal, January.

Vitality of the Seeds of Medicago Americana. — Some experiments, proving
the wonderful vitality of the seeds of this plant, were lately made by M.
Pouchet, the great advocate of the theory of spontaneous generation.
Some of these seeds, which had been submitted to uninterrupted boiling for
four hours, successfully withstood the high temperature, the outer integu-
ment resisting the water, so that, when the seeds were subsequently sown,
the young plants came up in from ten to twenty days.

A Barge Collection of Fossil Plants, prepared by the late Mr. Nicol, is
said, by the Journal of Botany, to have been purchased by the Trustees of
the British Museum. The collection is a most valuable one, and has cer-
tainly fallen into the best hands for the interests of science.

Fossil Botany. — Mr. Carruthers, of the British Museum, has published, in
the Geological Magazine and Journal of Botany some extremely valuable
papers on the Gymnospermatous fruits of the Secondary Rocks of Britain.
These papers are interesting not only for the full and clear descriptions they
contain, but because they show how much may be learned of the structure
and affinities of extinct plants, by the microscopic examination of sections of
fossils. It is very remarkable, that the conclusions arrived at by Mr.
Carruthers bear out, in some measure, those of Professor Unger. It seems
that the fossil vegetation of the Secondary Period finds its nearest existing

SCIENTIFIC SUMMARY.

201

kindred in the present flora of Australia. This fact is all the more remark-
able, because it happens also that the fauna of the Secondary Period has its
nearest allies in the existing fauna of Australia.

The Professorship of Botany in Trinity College, Dublin. — The chair vacant
by the death of Dr. W. H. Harvey, our late greatest algologist, has been
given to Dr. Alexander Dickson, of Edinburgh. Those of our readers who
have noticed our references from time to time to Dr. Dickson’s various
memoirs will agree with us in thinking that the selection made in this
instance has been a judicious one.

The Process of Fertilization in Fungi. — On this difficult subject a very
elaborate paper appears, from the pen of Herr H. Karsten, in the Botanische
TJntersuchungen. Herr Karsten’s observations tend to prove that several
groups of fungi, whose fruits have hitherto been considered distinct, are
produced in a manner common to all. We cannot here enter on an
analysis of Herr Karsten’s essay, but it will interest fungologists who
read it.

The Examination of Menispermaceous Seeds. — Mr. J. Miers, whose valu-
able Memoirs on the Menispermacese are being continued in the Annals of
Natural History, gives the following as- a practical mode of examining the
seeds of this order : — After macerating and freeing the putamen from its
pericarpial covering, introduce the point of the dissecting knife along the
peripheral line of suture. It is then easily separated into two valves, leaving
the kernel in an entire state. u We thus see the true form of the cell, its
position with regard to the condyle, and the mode of attachment of the seed,
the embryo and the albumen, if present, being thus obtained whole and
uninjured.”

Chemical Reagents in Botanical Diagnosis. — The Pev. W. A. Leighton, so
well known for his numerous contributions to the Science of Lichen-Botany,
has accidentally discovered that if hypochloride of lime be immediately
applied to specimens of Cladonice already moistened with hydrate of potash,
some very curious reactions are produced. Eor instance, if only a very
slight and scarcely observable reaction be produced by the hydrate of potash,
the immediate application of the hypochloride of lime will bring out a full
coloured yellow reaction, which colour may either remain permanent or be
eventually obliterated. Mr. Leighton lays great stress on these chemical
facts, and he contends that they afford a means of diagnosis better than any
hitherto employed. Indeed, he asserts that, had Sir W. Hooker, and other
great authorities, resorted to the chemical method, they would have achieved
a better system of classification than that which they based upon mere
“external characters and aspects.” Vide Annals of Natural History,
February.

A New Semper-vivum from the Salvage Islands is fully described in
Scientific Latin in the Journal of Botany for January.

The Leaves of the Dilleniacece. — In a memoir, laid before the French
Academy on the 18th of February, M. Baillon describes very fully the
anatomical features of this group of plants. The structure of the leaves
appears to be peculiar. Generally, they are composed of a beteromorphous
parenchyma. The cells beneath the upper epidermis are stick -like, and of
tolerably equal size, but, as one descends through the substance of the leaf,

Q 2

202

POPULAR SCIENCE REYIEW.

they become more irregular. The lower epidermis is formed of cells of a
very irregular outline, and, in certain species, bears stomata of an elliptical
form. Bundles of raphides are present in large numbers, and give the leaf
a sort of rough or rugose character. They consist of concretions of silica,
and are unaffected by any acid save hydrofluoric. They are well seen in
the leaf of Curatilla Americana , of which M. Baillon gives a minute
account. Vide Comptes Rendus, February 18.

The Nature of Sap-currents. — Herr Reichert has published an essay on
this subject, and he states his opinions in a series of conclusions. Of these
latter, the first three relate to the constitution of the sap-fluid. Herr
Reichert says, that in all cells containing fluids which rotate, two distinct
portions are present within the cellulose wall, viz., the central cell-fluid
which occupies the axis, and the mantle layer which exists between the
central cell-fluid and the cellulose capsule. The cell-fluid is generally
transparent ( Tradescantia Virginica being an exception) ; its chemical con-
stitution is not clearly understood, and it is the portion of the cell-contents
which does not participate in the rotation. The mantle-layer consists of
the gelatinous protoplasm, chlorophyll corpuscles, other smaller particles, the
cell-nucleus, and certain microscopic crystals.

CHEMISTRY.

New Test for Cobalt in Solution. — Mr. William Skey, Analyst to the Geo-
logical Survey of New Zealand, has communicated to a late No. of the
Chemical News a new test for the presence of cobalt in solution. If, he says,
ammonia in excess be added to a solution of cobalt in tartaric acid, then an
addition of ferricyanide of potassium produces a very dark-red coloration.
So intense is the colour thus produced by the ferricyanide, that it will
reveal the presence of cobalt in solution when all other tests fail, its
delicacy being about four times greater than that of carbonate of ammonia.
A solution of cobalt, prepared as indicated above, so as only to contain
part of cobalt, when placed in a f-inch test-tube, is very distinctly
coloured by the addition of a soluble ferricyanide, and even when diluted
down so as to contain but one part of cobalt in 400,000 parts of the liquid,,
the coloration is still distinctly visible in a bulk of a few ounces.

Action of Bismuth on Phosphoric Acid. — In the Zeitschrift fur Chetnie7
M. Brown states the effects of bismuth on phosphoric acid as very re-
markable. When a fragment of bismuth is thrown into u glacial phos-
phoric acid infusion ” the metal fuses to a bright globule, from which small
flames are emitted. This phenomenon is sometimes so strong that particles
of incandescent bismuth are thrown out of the vessel, forming a shower of
sparks. There finally remains a spongy mass of bismuth, and a white
powder, which is phosphate of bismuth. The flames which appear arise
evidently from the phosphide of bismuth which would be formed, and
which decomposes by giving up its phosphorus, or by forming phosphuretted
hydrogen in contact with the water of constitution of the phosphoric
hydrate. — Chemical News.

SCIENTIFIC SUMMARY.

203

Determination of Oxygen in Organic. Analysis. — At the meeting of the
Chemical Society of London, held on the 21st of February, Mr. E. T.
Chapman read a paper, entitled u Limited Oxidation : Determination of the
Oxygen Consumed,” which contained a suggestion for a more facile method
of estimating oxygen in organic analysis than that in general use. The
details are much too technical for our pages, hut we call attention to the
paper, as perhaps interesting to those who are pursuing organic chemical
investigations.

The Formula for Purpurine has at last been settled as C10H607, thus
putting an end to the controversy between M. Schiitzenbergen and M.
Bolley. The latter now agrees to the formula above, but, in other details,
there is still considerable difference between the views of these chemists.

New Petroleum Compound. — Chimogene is the name of a new substance
procured by condensing the gases first coming over from petroleum. It
has been produced by Prof. Van der Weyde, of Girard College, U. S. The
new liquid boils at 40°, and produces intense cold by evaporation.

The Preparation of Tinctures. — On this important point some valuable
observations have recently been made in the Journal de Pharmacie , by M.
Filhol. It appears, from his inquiries, that many of the tinctures kept in
our druggists shops and dispensed to patients must have very different
qualities from those assigned to them in the treatises on Materia Medica.
M. Filhol makes the following statements : —

“ A tincture prepared from the leaves of a plant will be of a beautiful
green colour, due to the presence of chlorophyll, and will, under the in-
fluence of hydrochloric acid, undergo transformations, which M. Fremy
has described, and which I have studied myself. Now, these transforma-
tions do not take place in a tincture which has been prepared for several
months, and the most essential characteristics of chlorophyll disappear.
“ The petals of the ranunculus, macerated in alcohol, give a golden-
yellow tincture, which, on the addition of an equal volume of hydrochloric
acid, turns green. After the liquid has been filtered, a yellow substance
remains on the paper, and the filtered liquid is of a pure blue colour.
Nothing of this kind takes place when the tincture has been kept some time.
Then the liquid remains yellow in spite of the addition of hydrochloric acid.
In this case the xanthine of the flowers has been altered, as well as the
■chlorophyll.”

The Separation of Palladium and Copper. — A novel method for the
separation of these metals has been discovered by Professor Wohler, and
has been described by him in the pages of the Chemical News'. — The
mixed liquids are dissolved in aqua regia, and the excess of nitric acid
is driven off by heat. The liquid is then saturated with sulphurous acid
gas, and a solution of sulphocyanide of potassium is added. This has no
action upon the palladium, whilst it precipitates the copper in the form
of a white subsulphocyanide, 0u2C2NS2. This may easily be changed into
Cu2S or CuO, and the quantity of copper thereby ascertained.

Amount of Carbonic Acid in the Air. — Some interesting observations have
been carried out by Mr. T. E. Thorpe, and have been described to the
Chemical Society (January 17). His experiments were conducted on the
method of Pettenkofer, an aqueous solution of baryta being used to absorb

204

POPULAR SCIENCE EEYIEW.

the carbonic acid from a known volume of air, the excess of baryta beinsr
ascertained by tbe use of a standard solution of oxalic acid. Mr. Thorpe’s
first experiments were made in tbe Irish Sea, in August, 1865, on board tbe
“Bahama Bank ” light ship, which is situate seven miles from Douglas, Isle
of Man, and consequently about equidistant from the shores of England,
Scotland, and Ireland. The results and meteorological conditions are given
in the form of a table, wherein it is seen that there is no perceptible varia-
tion in the amount of carbonic acid during the day and night, the hours of
4 a.x. and 4 p.ir. having been selected for the observations, these times
coinciding with the maximum and minimum temperatures. Similar ex-
periments were made last year in many latitudes of the Atlantic Ocean
during voyages to and from the Brazils. The results are nearly identical
with the former, and the amount of carbonic acid is said to be 300 parts in
10,000 of air, as the general average of the whole series of seventy-seven
observations.

A Test for Wood-fibre in Paper has been suggested byM. Behrend. The
suspected paper is touched with strong nitric acid. The presence of wood
is indicated by the paper being turned brown, especially on the application
of heat. This test is said to be more certain than the sulphate of aniline
one.

The Determination of the Nitrogen in Ammoniacal Salts. — Herr Knops’
method, which is a modification of Herr Wohler’s, which consists in treat-
ing ammoniacal salts with bleaching powder, has been highly spoken of by
M. Dietrich. According to an account in the Philosophical Magazine for
February, the decomposing solution is prepared by precipitating good
bleaching powder with carbonate of soda, and adding two to three grammes
of bromine to a litre of the solution after it has been made strongly alkaline.
Its strength is then estimated by a standard solution of arseniate of soda.
Fifty cubic centim. of this solution had the power of liberating 200 milli-
grammes of nitrogen. For the determination, 50 cubic centim. were
always taken, and substance always dissolved in 10 cubic centim. of water,
or stirred up with it, in case it was insoluble. Making the usual correction
for the volume used off, and allowing for the gas which remained in solution
in the liquid, M. Dietrich obtained very accurate results with this process
of Wohler and Knops.

The Reducing Action of Zinc has been recently studied by Herr Stahl-
schmidt, who has published a paper on the subj ect in Poggendorff s Annalen.
In the presence of a soluble alkali, finely divided zinc reduces nitrates to
nitrites in the most rapid manner. Hence, as has been suggested, zinc may
be employed for the conversion of the former into the latter. Commercially,
it may be obtained at a cheap rate. It is to be found in all zinc- works, and
consists of — zinc, 39-99 ; lead, 2-47 ; cadmium, 4*09 ; oxide of zinc, 49-76 ;
and carbonate of zinc, 3-29. Washing this crude powder in acids is all
that is required to prepare it for the reduction of nitrates.

u The Laboratory ,” a new chemical and physical journal is, we believe, to
make its appearance on the 5th of April. Its name affords a clue to the
nature of the subjects on which it will treat. We trust the new venture
may be a successful one, but we fear the commercial experience of those
who have had to do with new technical and “ class,” scientific periodicals is

SCIENTIFIC SUMMARY.

205

opposed to such experiments in publication. The new journal will, in form
and size, resemble Notes and Queries , and rumour says it is likely to be ably
conducted.

Action of Potassium on Hydrocarbons. — M. Berthelot continues his re-
searches on this subject. At a late meeting of the Chemical Society of
Paris he stated, that not only acetylin, but also cumol and napthalin were
attacked by potassium. The same effects were produced on anthracen, and
most of the less hydrogenized hydrocarbons. Benzol and hydrocarbons rich
in hydrogen are not easily attacked.

Thorina in Euxenite. — Professor Chydenius, of Helsingfors, in Finland,
states that he has detected the presence of thorina in euxenite.

Chemical Analysis of Variegated Strata. — The relation between chemical
composition and the variegated character of certain geological strata has
been explored by Mr. George Mair, F.G.S. At a late meeting of the Geo-
logical Society Mr. Mair gave the results of some analyses of the light and
dark parts of various slates, sandstones, &c., in which iron was sought,,
proving that the lighter blotches, spots, and stripes, contain a smaller pro-
portion of the colouring oxide than the average mass — a proportion which
implies an actual difference in the percentage of the metallic iron, and which
could not be accounted for by any mere difference in the state of its combin-
ation. This shows, he says, an actual departure of a part of the colouring
oxide out of the colourless patches, and a dispersive process which seems
to be the very reverse of the segregation of nodules of carbonate of lime and
carbonate of iron out of a clayey matrix. Among the forms of variegation
referred to were : (1st) that resulting from the segregation of dark blotches
out of a lighter matrix, the evenness of colour of which does not appear to
have been materially affected by the withdrawal of a part of its colouring
matter ; (2nd) that resulting from the segregation of dark blotches out of a
lighter ground, each of which is concentrically surrounded by a distinct and
well-defined zone lighter than the general ground ; (3rd) strata variegated
with light blotches containing a smaller proportion of colouring matter than
the general ground, but not arranged concentrically round a darker nucleus ;
(4th) the variegation of coloured strata with both light and dark blotches,
containing respectively a smaller and larger proportion of the colouring oxide
than the general ground, but which are not arranged, as in the second case,
concentrically with each other.

Conversion of Carbonic Oxide into Formic Acid. — This metamorphosis,
which is certainly one of the wonders of modern organic synthesis, has been
achieved by M. Berthelot. Of the method pursued by M. Berthelot the
following description was given by Dr. Grace Calvert, in one of his lectures
before the Society of Arts : — 11 Oxide of carbon,” said Dr. Calvert, u which
is highly poisonous, is the gas chosen by M. Berthelot to produce formic acid.
To arrive at this end, he pours, at the bottom of a large glass vessel, a strong
solution of caustic lye of soda or potash, filling the vessel with oxide of carbon.
After giving a rotatory motion to the glass vessel, the oxide of carbon is
absorbed by the potash, and each two chemical proportions of oxide of car-
bon, in fixing one chemical proportion of water, are converted into formic
acid, which unites with the potash to produce formiate of potash or soda.”

Chemical Manures. — All who are familiar with scientific agriculture are

206

POPULAR SCIENCE REVIEW.

aware How dependent upon the cHemist the Husbandman is. It may, there-
fore, interest our readers to know the character of the mineral manures
employed by our neighbours on the other side of the English Channel. The
manure applied at the Emperor’s model farm, near Vincennes, by M. Ville,
is prepared as follows : —

Slaked lime .....

200 kilos, cost

2 fr.

Phosphate of lime

400 „ „

80 „

Nitrate of soda ....

500 „ „

200 „

Potasse raffinee (carbonate of potash)

200 „ „

190 „

1300 kilos.

472 fr.

The above is the quantity required per hectare. Vide Chemical News ,
February 8.

Labels for Reagent Bottles. — Now that the new notation and nomencla-
ture are coming so much into general use, chemists can adopt no better
method of familiarizing themselves and their pupils with the new system
than by placing the new labels on their reagent bottles. In this way, their
eyes being frequently turned on the bottles, they cannot fail to substitute
the new formula and terms for the old ones. We are, therefore, glad to
state that a very perfect set of new labels, well printed and gummed, has
been issued by Messrs. Jackson & Townson, of Bishopsgate Street
W ithin.

Separation of Strychnine from Morphine. — Bichromate of potash, when
used as a test for strychnine, is ineffective if morphine be present. This is
a matter of great importance, and which toxicologists should bear in mind.
However, a remedy has been proposed by M. Rodgers, who states, in the
Journal de Chimie Medicale , that the two bases may be separated by chloro-
form or by benzol, which dissolves the strychnine, but only partly dissolves
the morphine.

New Filtering Apparatus. — The Chemical News states that an economic
filter and percolator, of an ingenious and useful kind, has been devised by
Mr. F. W. Hart. By a peculiar combination of syphon-tube and filtering
medium, any test-liquid may be drawn from a bottle in a state of limpidity,
and, if necessary, returned again turbid to the stock for refiltration. By
slight modifications, the apparatus is used for filtering alcoholic ethereal or
caustic alkaline solutions out of contact with the air, and it can be adapted
to a water bath, so as to admit of the filtration of gelatinous liquids. The
apparatus is specially contrived for use amongst photographers, but it is
evident that there are many uses in chemical, pharmaceutical, and manufac-
turing laboratories to which this apparatus can be economically applied.

Glycerine in Crystals. — Mr. W. Crookes, F.R.S., has described the singu-
lar phenomenon of crystalline glycerine. The specimen in which the crystals
were discovered had come by rail from Germany, and it is thought that the
vibration of the railway journey and the extreme cold of the season con-
duced to the production of a solid state. Mr Crookes gives the following
account of a portion of the solid crystalline mass : — u A large block of this
solid glycerine, weighing several hundredweight, suspended in a somewhat
warm room, took two or three days to liquefy, and a thermometer inserted

SCIENTIFIC SUMMARY.

207

in the fusing mass indicated a constant temperature of 45° F. In small
quantities the crystals rapidly fuse when the bottle containing them is
placed in warm water. The original glycerine was pale brown ; the crystals
formed from it are nearly white, whilst the liquid which drains away from
it is dark brown. In quantity, the solid glycerine looks very like a mass of
sugar candy. The isolated crystals are sometimes as large as a small pea ;
they are brilliant, and highly refracting j when rubbed between the fingers
they are very hard, and they grate between the teeth. Their form appears
to he octahedral, hut this is difficult to ascertain accurately, owing to the
viscidity of the mother liquor which adheres to them.” The specimen
examined was first discovered by Dr. W. S. Squire, of the firm of Burgoyne,
Burbidges, and Squire, of Coleman Street.

The Absorption of Hydrogen and Carbonic Acid by Melted Copper . — M.
Caron has presented to the French Academy a memoir on this subject. The
following is the account given of the mode of experimentation : — Copper of
good quality, weighing about 200 grains, is melted in a vessel placed in a
porcelain tube, and by degrees is passed over it a stream of hydrogen, the
apparatus being so arranged that the copper could be seen during the whole
operation. As soon as the metal fused it appeared to intumesce, and water
was condensed on the cool part of the apparatus. When the oxide which the
copper contains is completely reduced, the surface of the metal is as brilliant
and mobile as that of mercury. On cooling, a little before solidification,
the mirror-like surface becomes agitated and appears to boil up, the escaping
gas projecting a multitude of fine drops of copper. The metal then swells,
and the solidification terminates by a final incomplete eruption. The ingot
of metal, after cooling, is found to be porous. Exactly the same phenomenon
takes place when the hydrogen is replaced by carbonic oxide.

GEOLOGY AND PALAEONTOLOGY.

Colliery Explosions and the Barometer. — Mr. J. Rofe writes to the Geo-
logical Magazine , and shows that colliery proprietors have only to watch the
barometer, and provide, in accordance with its indications, for the supply of
air to the mines. Alluding to the well-known u Blowing well ” of Preston,
in Lancashire, he states that, some time since, in a well recently constructed
by him as a cesspool to some chemical works, he observed the phenomena
characterising the 11 Blowing well.” When the atmospheric pressure
diminished the air came from the well loaded, to a disagreeable extent,
with the offensive vapour from the cesspool. On continuing his observa-
tions with a barometer, he found similar results. He concludes, from these
facts, that a coal-mine must be regarded as a gigantic well, from which,
when the atmospheric pressure diminishes, the air expands, and rushes out
with great violence. This circumstance is not, of itself, dangerous ; but if
there be an excess of gas in the mine, and, at the same time, from accident
or carelessness, a means of ignition, then, indeed, the consequences are very
likely to be serious. Hence the barometer becomes the miner’s safest
guide.

208

POPULAR SCIENCE REVIEW.

Consolidated Blocks in the Drift of Suffolk. — At the meeting of the Geo-
logical Society, on January 23, Mr. George Maw recorded the occurrence of
large isolated masses of consolidated sand and gravel in the drift intervening
between the chalk and boulder clay of the high ground of Suffolk. Many of
the masses are several tons in weight. Although they occur at a general
level, they do not form a connected band, loose drift, out of which they
were evidently composed, forming a horizontal combination of their strata.
The drift is largely charged with chalk-detritus, which also occurs in the
softer blocks. Some of the blocks are extremely hard and compact, and in
these the sandy agglomeration seems to have given place to a crystalline
structure ; but the hardest of those found in situ were resolvable into sand
by the action of hydrochloric acid, and appeared to be merely held together
by a calcareous cement.

A Fossil Myriapod from the Scotch Coal-Measures. — Mr. Henry Wood-
ward lately presented a paper to the Geological Society of Glasgow, de-
scribing a curious chilognathous myriapod, found by the late Mr. Thomas
Brown in the upper coal-measures of Kilmaurs. The specimen described
occurs in a nodule of iron stone coiled up somewhat in the form of the
letter J, and measures about two inches. The body contains thirty seg-
ments, each of which bears a slightly raised papilla, indicating the position
of the tracheal openings ; while, to the sternum of each segment, a pair of
slender feet appear to have been articulated. These feet are easily seen to
be composed of a number of joints, as is the case with recent myriapoda.
“ No soft-bodied annelid would be preserved in this condition,” the body-
rings of worms which Mr. Woodward had examined, from Solenhofen, for
example, being indicated rather by a stain upon the slab than by any re-
lievo evidence of their presence, as shown in the specimen described. Mr.
Woodward concludes that this myriapod possessed a chitinous exoskeleton
sufficiently firm and strong to leave the impression of its limbs and joints in
the soft clay in which it was buried.

A new species of Plesiosaurus has been purchased by the British Museum.
The specimen is from the Lower Lias, near Charmouth, and has been named,
by Professor Owen, Plesiosaurus laticeps. It measures nearly 14 feet long,
and, with the exception of the displacement of a few caudal vertebrae, the
vertebral column is in a complete and natural state. It is mounted with
the ventral surface toward the observer, and, with the exception of a portion
of the paddles and part of the muzzle, the skeleton may be said to be
complete.

Foliation of Metamorphic Rocks. — Mr. G. H. Kinahan has written a very
interesting memoir on the above subject, the gneiss and schist of Yar
Connaught having specially received his attention; and, from Mr. Kinahan’s
observations, it would appear that the foliation of these rocks seems generally
to follow some variety of laminated and rarely the cleavage planes. Mr.
Kinahan describes six varieties of foliation, one of which may follow the
cleavage planes, while the five others follow the lamination ; the parallel
foliation being caused by parallel lamination ; the oblique, by the oblique
lamination ; the spheroidal, by the spheroidal lamination ; the crumpled, or
wavy, by the crumpled lamination ; and the curled, by the lamination that
is round the nodules. An instructive case is cited of this structure in the

SCIENTIFIC SUMMARY.

209

to inland of Killaguile, where the foliation of the schist curls round nodules
of gneiss, the latter being foimd to be obliquely foliated.

A new specimen of Telerpeton Elginense. — A new specimen of this in-
teresting fossil reptile, which is the property of Mr. James Grant, of Lossie-
mouth, has been described by Professor Huxley. The casts described con-
sisted of impressions of the bones of the skull, together with the lower jaw,
the teeth, most of the vertebrae and ribs, the greater portions of the pelvic
and scapular arches, and representatives of most of the bones of the fore and
hind limbs. Professor Huxley concludes that the creature is a true reptile
of the lizard group, and that it by no means belongs to the amphibia. The
hind feet appear to be peculiarly anomalous, the fifth digit presenting only
two phalanges — a structure which differs from that of all lizards, recent and
fossil, which have been yet examined.

Fossil Man in the Rhine Valley. — In the Lehm of the Valley of the
Rhine, near Colmar, there is a marly deposit composed of a mixture of
clay, fine sand, and carbonate of lime. It forms part of the diluvial beds,
and in it M. Faudel has found a number of human and other remains.
These consisted of shells, bones of a huge stag, teeth of Flephas primigenius ,
and a human frontal and right parietal bone of a man of middle size. M.
Faudel concludes that man was contemporaneous with the mammoth fossil
stag and bison.

Varieties of Denudation. — In an able memoir which he has recently
published, Mr. A. B. Wynne, after bringing forward an abundance of
evidence to show that no one form of denudation can be supposed to have
exclusively affected the outer form of the globe, draws the following con-
clusion : — That the similarity of the general results , notwithstanding differ-
ences in the causes from which they may have proceeded, and their close
connection with geological structure, involves their origin in some obscurity,
which may lead to error, if a prejudice exist in favour of either a marine or
sub-aerial agency, and that while great changes are effected by the endless
action of the sea, the equally continuous atmospheric agencies are sufficiently
powerful to produce, in the lapse of time, results so enormous, that time
also is required for their full appreciation.

Fossil Fchinoderms from Sinai. — Dr. P. Martin Duncan, who has been
examining the cretaceous rocks of Sinai, has written an interesting paper on
the subject of his investigations. The existence of cretaceous rocks in the
district of Sinai has been surmised for several years ; but, owing to the
scarcity of fossils, they have not been correlated with any of the Asiatic
formations. An examination of the Echinodermata collected by the Rev.
F. W. Holland from the limestones of Wady Mokatteb and Wady Badera
has enabled Dr. Duncan to show their parallelism with the red limestones
in South-eastern Arabia, the fossils from which he described in a former
paper. All the species not determined are well-known forms, characteristic
; of the typical Upper Greensand of Europe ; but those formerly described
| from Sinai by MM. Desor and D’Orbigny seem to be peculiar to that region.
Dr. Duncan states that by adding the Echinodermata from Sinai to those
from South-east Arabia, we obtain a fauna eminently characteristic of the
Middle Cretaceous period ; and, in conclusion, he drew attention to the in-
teresting fact that the majority of the wide-wandering Echinoderms had a

210

POPULAR SCIENCE REVIEW.

tendency to vary from their types both in Europe and in Arabia, while the
rest remained persistent in form.

The Glacial Period in America. — Mr. Thomas Belt has sent us a reprint
of a memoir published in the Transactions of the Nova Scotian Institute of
N'atural Sciences [Vol. I. Part 4]. It is upon the above subject, and ex-
presses the views of the author, who is evidently well acquainted with the
.glacial geology of North America. The following are the principal conclu-
sions which Mr. Belt has drawn : — 1. The arrangement of the heaps of granite
in the flanks of hills, and the distribution in them of grain gold in Nova
Scotia, are opposed to the theory of the submergence of the country, either
during or since the Glacial period. 2. The submergence of part of eastern
North America, during which the marine beds of the Champlain period
were formed, was not participated in by the southern coast of Nova Scotia.
3. To explain the movement of land ice from the Arctic regions southwards,
it is not necessary to suppose that the continent to the north must have
been greatly elevated, nor do the facts connected with the distribution of
the drift agree with such a supposition. 4. That there was some elevation
of northern lands during the Glacial period is, however, probable : — Firstly ,
because all the oscillations of level of the lands in the Northern Hemisphere
since the Glacial period, with which we are acquainted, have been greatest
towards the pole ; and secondly , because a rise of land sufficient to prevent
the entrance of heated currents to the polar basin, would occasion a great
accumulation of ice in the circumpolar regions, by the heat of the tropical
and sub-tropical waters being spent in evaporation instead of, as at present,
in melting the ice within the Arctic circle. 5. The drift-beds were formed
during the retreat of the ice, and not during its greatest development. 6.
Terraces and stratified beds in lateral valleys, were formed when these were
filled with water, dammed back by the glaciers that still flowed down the
main valleys.

The Glacial period , in its relation to the eccentricity of the" earth’s orbit,
is the subject of a highly philosophical essay, which appeared in the Philo-
sophical Magazine for February. The paper should be carefully studied by
those of our readers who are interested in the point it deals with. The fol-
lowing paragraph will give an idea of the author’s views. u When the ex-
-centricity reaches a high value and one of the solstice points is in podhelion,
the difference between the temperatures of the two hemispheres must be
very great. The hemisphere which has its winter in aphelion , and mider a
condition of glaciation, is much colder than the opposite hemisphere, which
has its winter in perihelion and enjoying an equable climate ; and the con-
sequence is, the aerial currents from the pole to the equator must be much
stronger on the colder hemisphere than on the warmer, because the dif-
ference between the temperature of the pole and the equator is greater on
the former hemisphere than on the latter. When the northern hemisphere,
for example, is under glaciation, the north-east trade-winds will be much
stronger than the south-east. The medial line between the trades will con-
sequently lie a considerable distance to the south of the equator. The effect
of the northern trades blowing across the equator to a great distance will be
to impel the warm water of the tropics over into the Southern Ocean. And
this, to an enormous extent, will tend to exaggerate the difference between

SCIENTIFIC SUMMARY.

211

the temperature of the two hemispheres.” Mr. Croll gives a long series of
tables showing the different values of the excentricities, at different epochs
and from them calculates the dates of the Glacial periods.

Nests of altei'ed rock in the grey Granites of the Southern Uplands. — The
subject of the metamorphosis of rocks is now occupying geologists, and the?
memoir lately contributed to the Geological Magazine by Mr. James Geikie
must therefore be of great interest to our readers. After dwelling at some
length on the metamorphosis of aqueous rocks as shown in certain specimens
which he examined, Mr. Geikie passed on to the above subject. These nests
he says, must be familiar to all who have ever travelled over large granite
districts. They consist of a fine-grained or semicrystalline dark baked-like
rock, which is enclosed in a granitic basis. Frequently they are seen to
show traces of lamination, but their most usual character is that of exceed-
ingly fine-grained mica-schist whose dark or blackish hue is due to the
large quantity of mica present. Most commonly, says Mr. Geikie, they are
“ of very irregular shapes, and are by no means confined to those portions of
the rock that abut upon the outlying bedded or aqueous strata, but are scat-
tered indiscriminately throughout the granite. The granite and the rock
of a nest are firmly knit together, so that when a suitable edge has been ob-
tained, a smart tap with the hammer will fetch away a good specimen to
show the junction. This is commonly so marked that one may place a
knife-edge upon it ; but I have sometimes (though rarely) met with u nests ”
the fine-grained or compact rock of which seemed to pass by insensible gra-
dations, both of colour and texture, into the outside granite. As far as my
observation goes, the “ nests ” are, as a rule, harder, tougher, and less easily
weathered than the granitic matrix, so that on exposed surfaces the “nests ”
usually stand out in relief. In some granites and granitoid rocks, however,
the reverse is the case, the “ nests ” decomposing out and leaving behind
them little pits and irregular hollows. When the granite and the contained
nests are of the same or nearly similar hardness, it sometimes happens that
decomposition has set in along the line that separates the one from the other,
affecting both equally.” Vide Geological Magazine , No. 30.

Origin of Petroleum. — Although nearly all geologists are agreed as to the
organic origin of Petroleum, a great many are of opinion that the rock-oil is
the result of a natural distillation of coal. Professor Hitchcock, however,
no mean authority, comes to a different conclusion. Admitting, with all who
have carefully studied the matter, that Petroleum is of organic origin, he
says, that in his opinion it comes from plants, and that it is not, as some have
suggested, a fish-oil or a substance altered to adipocere. It does not appear
to be the result of a natural distillation of coal, since its chemical composi-
tion is different from the oil manufactured artificially from the cannels, con-
taining neither nitro-benzole nor aniline. Moreover, petroleum occupied
fissures in the Silurian and Devonian strata long before the trees of the Coal
period were growing in their native forests. The nearly universal associa-
tion of brine with petroleum, and the fact of the slight solubility of hydro-
carbons in fresh, but insolubility in salt water, excite the inquiry whether
the salt-water of primaeval lagoons may not have prevented the escape of
the vegetable gases beneath, and condensed them into liquids.

The Rev. W. S. Symonds and the Belgian Bone Caves. — We are sorry to be

212

POPULAE SCIENCE EEYIEW.

obliged once more to call our readers’ attention to an unpleasant subject. We
allude to tbe controversy wbicb took place some time since in the pages of
tbe now defunct Reader relative to tbe paper on tbe Belgian bone caves, read
before the Cotteswold club by Mr. Symonds and Sir W. V. Guise. Briefly,
we may say, that Mr. Carter Blake accused Mr. Symonds of publishing in-
telligence wbicb be had received in tbe course of conversation with M.
Dupont and wbicb tbe latter never intended to be made public. This was a
very grave charge ; and in commenting upon it in our October No. we
called on Mr. Symonds for an explanation or contradiction of Mr. Blake’s
assertion. We were led to do this with more confidence from tbe circum-
stance that we observed no reply to Mr. Blake’s letter in tbe Reader. Since
then we received a communication on tbe subject from Mr. Symonds in
wbicb be produces tbe evidence of M. Dupont in justification of tbe course
pursued in tbe publication of tbe paper on bone caves. Unfortunately this
letter arrived too late for insertion in our January No. We have now
therefore, even at tbe eleventh hour, to grant what is due in all fairness to
Mr. Symonds — to completely exonerate him from tbe serious accusations
expressed in Mr. C. Blake’s letter. M. Dupont must know best whether
be has been dealt with discourteously, and bis letter therefore is tbe most
satisfactory explanation of tbe matter. We cannot print this letter in full,
but we give tbe following quotation from it as an illustration of what M.
Dupont thinks of tbe affair : —

‘ Je ferai seulement remarquer que Messieurs Guise et Symonds m’ont
prete des opinions que je n’ai pas, sur l’bomme et les phenomenes quater-
naires ; mais je suis convaincu que ces inexactitudes dans leur compte-rendu
ne doivent etre attributes qu’a une erreur involontaire resultant de l’emploi,
dans la conversation que j’ai eue avec eux, de la langue fran^aise, qui na-
turellement ne leur est pas familiere.’

This decided disavowal of tbe views held by Mr. Symonds and Sir W.
Guise is an adequate refutation of Mr. Blake’s statement.

Rre-historic Settlements. — In a series of Essays published late last year,
Dr. Oscar Fraas of Stuttgart describes a number of pre-bistoric remains wbicb
be has discovered at tbe bead of tbe brook Scbussen, wbicb runs into tbe
Lake of Constance. In tbe course of excavating for a mill-pond several
specimens were found. Among others some gigantic horns of tbe reindeer
from four to five feet long ; many of these were split to procure tbe marrow
and some were converted into weapons, tools, &c., for agriculture, &c.

MECHANICAL SCIENCE.

Gas Engine. — A new form of engine worked by tbe explosion of coal gas
has been recently introduced into this country by M. Hugon, who claims to
be tbe original inventor of tbe Lenoir engine, wbicb has been in use for
several years. In this engine tbe complicated and delicate arrangements of
electric batteries employed for tbe ignition of tbe gas in tbe Lenoir engine

SCIENTIFIC SUMMARY.

213

are dispensed with. The ordinary slide valve is enlarged, and by an inge-
nious arrangement the ends of the valve, in its travel, project beyond the
ends of the valve chest, so as to expose a gas jet, contained in a cavity of
the valve. This jet is lighted at a fixed burner, and at the return of the
valve ignites at the proper moment the mixed gases in the cylinder. M.
Hugon introduces a jet of water into the cylinder at the instant of explosion
which by its instantaneous evaporation diminishes the intensity of the tem-
perature, keeps the cylinder cool, equalizes the pressure and assists in lubri-
cation. He also provides separate pumps for maintaining the supply of the
explosion compound and the gas for the exploding jets, at the requisite
pressure.

S 'team Rollers. — One of the great steam rollers recently introduced in
Paris has exploded in the streets with fatal results.

Chilled Shot. — A controversy has arisen between Mr. Nasmyth the well-
known inventor of the steam hammer, and Capt. Palliser as to the invention
of chilled shot. Mr. Nasmyth, it appears, proposed cast-iron chilled shot, for
penetrating armour, at the meeting of the British Association at Cambridge,
in October 1862. Capt. Palliser, on the other hand, claims that the ogival-
fronted form of his shot is an equally important part of the invention as the
material of the shot. And he has certainly been the first to show how
shot of suificient hardness could be obtained, by the use of a particular
quality of iron, and to demonstrate practically their effectiveness against
iron armour. On the other hand, Mr. Whitworth, in a letter to the Times ,
whilst admitting the penetrative power of the ogival-fronted cast-iron shot
when striking the target perpendicularly, still maintains that they are useless
when striking obliquely, and that sound well-tempered steel shell with flat
fronts are the only projectiles to be relied on under the varied conditions of
naval warfare.

Mont Cenis Railivay. — In a paper read before the Institute of Civil Engi-
neers, Capt. H. W. Tyler has fully described the results of experiments with
Mr. Fell’s locomotive, which has been adopted for surmounting the steep
gradients and sharp curves of the Mont Cenis route. On Mr. Fell’s system
an intermediate or centre rail is adopted, against which horizontal wheels
worked by the engine are pressed by springs so as to yield any requisite
amount of adhesion. The engine constructed for the Mont Cenis line is
partly of steel ; its weight fully loaded does not exceed 17 tons. There are
two 15-inch cylinders working both the four coupled horizontal, and the
four coupled bearing wheels. The pressure on the additional horizontal
wheels can be varied by the engine driver at pleasure ; during the experi-
ments it amounted to from 2\ to 3 tons on each wheel, or 10 tons altogether,
but provision was made for increasing this pressure to 24 tons if necessary.
During the official trials, with a load of 24 tons exclusive of the engine, on
an average gradient of 1 in 13, with curves of 2 to 4 chains radius, the speed
of 6-65 miles to 7 ’46 miles per hour was attained in ascending. With a load
of 16 tons the speed was 10 miles.

Snow Ploughs. — In Engineering for March 1 are described and figured the
snow ploughs which are employed by Mr. William Strandley, on the High-
land Bailway of Scotland, for clearing a way for the trains through the
heavy snow drifts to which that line is peculiarly liable. The largest of

214

POPULAR SCIENCE REVIEW.

these consists of a massive timber framing, carrying a sort of gigantic cut-
water and mould-board. Driven by five or six luggage engines, this plough
will clear a way through drifts 10 or 11 feet deep at the rate of 25 miles per
hour. Dor smaller drifts a medium sized plough is used attached to a pilot
engine running in front of the trains, when occasion requires ; and during the
winter each engine is fitted with a still smaller plough, not rising above the
buffer beam of the engine but capable of doing good service in drifts of 2 or
3 feet deep.

Safety Valves. — We need not fear that the sphere of mechanical research
is exhausted, when so simple a matter as an ordinary safety valve still re-
quires and rewards investigation. Mr. Thomas Baldwin has communicated
to the Society of Engineers some very interesting experiments on the dis-
charging power of safety valves, or the influence of the form of the valve on
the lift of the valve for any given excess of pressure in the boiler over the
weight with which the valve is loaded. The valve employed in the experi-
ments was one inch in diameter, and was fixed in the manhole lid of an or-
dinary two-flued boiler. The following are some of the results.

Pressure in Boiler Weight on valve in lbs per sq. in.

Valve in lbs. per sq. in. in- when the valve lifted the under men-

cluding atmosphere tioned fractions of its diameter.

J_ ±_ 8 12 16

80 80 80 80 80

A .

. . 65

. 58±

53i

52±

51*

D

. 65 .

, . 53^

49±

48f

48

L .

. 67 .

. 56i

52

49*

48.i

M .

. 67 .

45

Valve A a disc valve, guided by outside pins j D, disc valve with inside
wings ; L, ordinary conical valve with 3 wings, and seat § in. wide ; M, disc
valve 1| in. diam.

These experiments show that we cannot have the ordinary valve of suffi-
cient area to allow the steam as rapid an exit as it ought to have unless the
valves be very large. Mr. Baldwin proposes a spherical valve with a pro-
jecting seating, so arranged, that when the valve opens, the steam acts on a
larger area of the valve than when shut. Such a valve If inch diameter he
considers twenty times as effective as a disc valve five times its diameter.

Casting Steel under pressure. — Mr. Whitworth has invented a system of
steel casting under enormous hydraulic pressure, with a view to produce a
material of more uniform and ductile quality, and requiring less subsequent
hammering or rolling. Steel shot of satisfactory quality have already been
produced and the process i3 to be extended to the manufacture of ord-
nance.

Turret Ships. — A very important discussion has taken place at the Insti-
tute of Civil Engineers on the American Monitor system which has found a
most able and competent advocate in Mr. John Bourne. There appears to
be little doubt that additions to our Navy will be made, in which a modifi-
cation of Capt. Coles’s and Ericsson’s plans will be adopted, and which will
carry armour 15 or 16 ins. thick and 20-ton guns. In these the hull will
follow the Monitor type, with its low deck almost level with the water, but
the turrets will be carried up through a raised breastwork rising 7 to 10 feet
above the deck.

SCIENTIFIC SUMMARY.

215

METALLURGY, MINERALOGY, AND MINING.

Iron Direct from the Ore. — M. C. Duprey proposes to adopt a new method
of manufacturing iron direct from the ore. He takes the ore — which has
been freed as far as possible from earthy matter— and, having crushed it, he
places it along with pulverised charcoal in thin sheet-iron canisters ; the
quantities employed being just sufficient when reduced to form a mass of
iron of the usual weight of a puddle ball. An ordinary sand-bottom iron-
heating furnace is brought up to a reducing heat, and with a thick clear fire
the canisters are introduced. The furnace is carefully maintained at a re-
ducing heat in the usual manner ; in fact the process is continued much in
the same manner as when sheet-iron is being annealed. Soon after intro-
duction the canister is annealed and toughened, so as to assume a polished
appearance. It should be the aim to keep the heat in this condition until
the metal is thoroughly reduced : should it be increased the canisters may
be prematurely destroyed. Deoxidation commences immediately on the
introduction of the ore, as proved by the blazing of carbonic oxide from
vents made for the purpose, and, by occasionally rolling, and at the proper
time compressing the canister, the oxidation is caused to continue without
intermission, until reduction is completed. The heat should then be raised
to weld or paste together the particles of iron, and then canister and con-
tents, being withdrawn, are welded, in any of the ways puddle ball is
usually treated. The saving by this method is estimated at something like
30 per cent, on the present method. — Vide the Artizan , January.

What our Coal-measures yield. — At a late meeting of the Manchester
Philosophical Society, Professor Page read a paper entitled “ What we owe
to our Coal-measures.” In the course of this he gave the returns of the
yield of coal in the years 1857 and 1865 respectively, and as the contrast of
the figures show the enormous increase in the quantity of coal removed
from our mines, we give the statistics for the benefit of those of our readers
interested in the subject : —

Durham and Northumberland .

1857.

tons.

15,896,525

1865.

tons.

25,032,694

Cumberland .....

942,048

1,431,637

Yorkshire ......

8,875,440

10,846,000

Derbyshire and Nottinghamshire

3,687,442

4,200,350

Warwickshire .....

398,000

859,000

Leicestershire

698,750

965,500

Staffordshire and Worcestershire

7,164,625

12,200,000

Lancashire ......

8,565,500

11,962,000

Cheshire ......

750,500

850,000

Shropshire

750,000

1,135,000

Gloucestershire, Somerset, and Devon-
shire ......

1,225,000

1,875,000

North Wales .....

1,046,050

1,983,000

South Wales and Monmouth

7,132,304

12,036,587

Scotland ......

8,211,743

12,650,000

Ireland

120,630

123,500

65,395,707

98,150,587

YOL. VI. NO. XXIII. R

216

POPULAR SCIENCE REVIEW.

Ensuring the Purity of Silver. — It is no easy matter to make sure of the
purity of silver. To those, therefore, who are working at this branch of
metallurgy we commend the admirable memoir of M. Stas, in the Annales
de Chimie, vol. lvi. p. 413. It has been translated into the Chemical News
for February 22.

Composition of Boronatrocalcite. — This peculiar mineral has had its com-
position variously set down by different mineralogists. Lately, however,
Mr. George Lunge has taken up this mineral for investigation. In a paper
published in the Chemical News he goes fully into the history of the
analyses given by his predecessors, and after explaining the method adopted
in his own inquiries, he sets down the formula as follows : —

2(NaO,2B03(+5(CaO,2BO3)+42 aqu.

This is very nearly exact ; there must, however, be a magnesium substi-
tuted for a very small quantity of calcium.

The Metal Manufacture of Prussia. — The forges and foundries in Prussia
amounted in 1884 to 1,421. The total production amounted to 1,610,000
tons of common metals and 56,701 lbs. of silver, representing in money a
sum of £5,816,187.

Telegraphic Communication in Mines. — At the Trafalgar Colliery, in the
Forest of Dean, Mr. Brain has exerted himself to provide electric communi-
cation between the men descending the shaft and those in the engine-
room, and above and below. The instrument is the same as one used on
the Metropolitan Railway. It is fixed in the engine-room in front of the
engineer. At the pit bottom the “ hanger-on ” is provided with a pair of
electrical tappers, coloured respectively white and red. On touching the
white tapper the bell in the engine-house is instantly struck, and the words

go on” show themselves on the dial plate attached. On touching the red
the bell is struck as before, and the word a stop,” in white letters on a red
ground (as indicative of danger), is shown. By a repetition of the touch
any number of knocks may be given. This also has been found to answer
admirably. Electrical communication has also been laid in by Mr. Frost
from Mr. Brain’s office to different parts of the works, so that he can be
instantaneously communicated with on any matter affecting the colliery.
The instruments employed are the common needle, and with bells attached.
— Vide Mining Journal , February 23.

Petroleum as Steam Fuel. — Mr. Richardson’s experiments, conducted
under the auspices of the Lords of the Admiralty, appear to have met with
more success than some people anticipated. The trials were made with the
petroleum boiler in Woolwich Dockyard. Mr. Richardson succeeded,
during the latter period of the experiments, in evaporating 18-91 lbs. of
water per pound of creosote during a trial of seven hours. The new fuel
gave off at times a great deal of smoke, which caused a most offensive
effluvium, the construction of the boiler being such as to impede a full
gaseous blast, sufficient to destroy and consume the smoke as intended. Mr.
Richardson has, it is understood, in consequence, applied to the Admiralty
for a large common marine boiler, for the purpose of future trials. It was
stated, as the opinion of the local naval engineers and other officers who
were present, that with such fuel the gunboats in the tropical seas would

SCIENTIFIC SUMMAKY.

217

be rendered habitable and comfortable. The experiments were attended by
a very large number of persons, representing the principal engineering and
shipping firms, and also by many owners of steam yachts, who are desirous
of using the new fuel instead of coal. — Vide the Times.

Oil-io ells in Baden have been recently discovered, and are said to be as
productive as the American springs. The oil is reported to be excellent.
The locality of the wells is Wiesloch.

Gun-cotton as a Blasting Material. — We learn that experiments have
recently been made in one of the Yorkshire coal-mines as to the value of
this substance as a substitute for gunpowder. It appears from the trials
already made, that, besides the superiority in power of gun-cotton over gun-
powder, it possesses — what in a coal-mine is most important — the property
of emitting no flame. Hence it can be used in cases in which the employ-
ment of gunpowder would be positively dangerous.

The Separation of Lead from Argentiferous Lead Ore. — The French cor-
respondent of the Chemical Neios , who displays a wonderful faculty for col-
lecting and popularising the most recent scientific news, states thatM. Cordure
has been more skilful than his predecessors, inasmuch as he has made use
of the affinity which lead has for silver, in order to extract the former from
the above-named ore. When the argentiferous lead is melted, a small
quantity of zinc is added, and, after an energetic brushing, the mixture is
allowed to repose. The alloy of zinc and silver, being lighter than lead,
rises to the surface, and, as it is less fusible, it cools sooner. By watching
the proper moment the silver can be skimmed off, united with zinc and a
small quantity of lead. The zinc and the lead are separated by remelting
the skimmed mass, and oxidising, by means of a current of hot air or super-
heated steam, and treating afterwards with hydrochloric acid ; the residue is
submitted to cupellation. Nothing hinders the chloride from being utilised
in its actual state, or being transformed into carbonate of zinc.

Prevention of Accidents from Fire-damp.— The explosions which now so
often occur in our mines are terribly destructive of life and property ) but,
strange to say, if they were much more frequent they would be less dan-
gerous. If, in fact, the gases were caused to explode before they have
collected in any large quantity, no serious damage would result. This is the
principle of the remedy proposed to the French Academy by M. Somonet.
He suggests the introduction into all the “ drifts ” of electrical conducting
wires, so that the inflammable gases may be set on fire by interruption of
the electric current before time has been given for them to collect to any
dangerous extent.

Neio Reactions of the Oxide of Tungsten. — It has been pointed out by Mr.
Skey, of the New Zealand Geological Society, that there are other reactions
of tungsten than those already indicated in books. If, for example, he says,
tungstic acid is made red-hot, and then brought in contact with a cold sur-
face, it becomes permanently black. This is due to the formation of an
oxide. The hot acid dropped into kerosene oil gives rise to the same effect.
The addition of acetic or tartaric acid prevents the blue precipitate of oxide
(resulting from the deoxidising of the acid by zinc) from being thrown
down and dissolves it, thus forming a characteristic blue solution.

Crucibles for Metallurgic Operations. — For inquiries in which a very high

r 2

218

POPULAR SCIENCE REVIEW.

temperature is employed lime crucibles are used, but there is much diffi-
culty in preparing them, and when made they are often broken. One of the
great difficulties in the way is that of obtaining blocks of lime of a sufficient
size for scooping out a crucible, most large blocks being cracked. Clay
crucibles lined with lime have been tried, but they too have failed, being
often melted themselves. Under these circumstances the following method,
suggested by Mr. D. Forbes, F.R.S., appears to be a good one. A clay
crucible, of somewhat larger capacity than the desired lime one, is filled
with common lamp-black, compressing the same by stamping it well down.
The centre is then cut out with a knife until a mere shell or lining of lamp-
black is left firmly adherent to the sides of the crucible, and about half an
inch or less in thickness, according to the size of the crucible ; this lining is
now well rubbed down with a thick glass rod until its surface takes a fine
glaze or polish, and the whole cavity is then filled up with finely-powdered
caustic lime and pressed down as before, and a central cavity cut out as
before, or the lime powder may be at once rammed down round a central
core of the dimensions of the intended lime crucible. The lime lining is
soft before it is placed in the furnace, but it soon agglutinates, and forms a
compact crucible, which is prevented acting on the outer one by the inter-
mediate stratum of lamp-black. This crucible will stand the heat of melted
wrought iron or cobalt without fusing or cracking. — Vide Chemical News ,
January 4.

A Mineral of Yttria in the Alps . — In the Annalen der Chemie Herr W artha
describes, under the title of Wiserine, an Yttriferous mineral which has
been found in the Haut-Valaise. It crystallises in square-based prisms
similar to zircon. It was supposed to contain silica and titanic acid, but
M. Wartha has found this to be an error, and that, excepting a little iron, it
contains only phosphoric acid and yttria. It is a phosphate of yttria, iden-
tical with the xenotime of Berzelius.

THE MEDICAL SCIENCES.

The Structure of Muscle. — In a late No. of Siebold and Kolliker’s Zdt-
schrift , Professor Kolliker publishes a paper on the subject of the compart-
ments seen in transverse sections of muscle. These were described some
years since by Herr Cohnheim, whose views have now been corroborated
by Herr Kolliker. In the present paper, the author concludes that the
muscles are really composed of fasciculi, and that the material which binds
the fibres together is different from that which unites what Mr. Bowman has
styled the sarcous elements.

Distribution of the Rods and Cones in the Retina of Mammalia. — In the last
No. of the Microscopical Journal there is a very able translation and con-
densation of Herr Schultze’s recent memoir on the retina. Those who are
interested in the comparative anatomy of the retina should read this paper
attentively. It is full of interesting details, and, among other matters, -it
gives an account of the distribution of the rods and cones of the retina in

SCIENTIFIC SUMMARY.

219

mammalia. From tliis we learn, tliat among the lower mammalia there is a
remarkable diversity with respect to the distribution of the rods and cores.
Whilst most of our larger domestic animals, especially the horse, ox, sheep,
pig, and dog, present an arrangement of those elements resembling that
which is seen in the human subject and in apes [except, of course, in the
absence of the macula lutea ], the cones, according to Herr Schultze’s obser-
vations, are entirely wanting in bats, hedgehogs, mice, moles, and guinea-
pigs. A sort of intermediate condition is met with in the cat, rabbit, and
rat, in which animals are found either very slender true cones, as in the
cat, or merely indications of them, as in the rabbit. But, in any case, the
rods preponderate so much that the cones among them may readily be over-
looked. In the rat, the rods are the longest and slenderest which Herr
Schultze has yet found.

Structure of the Liver. — Dr. Lionel Beale’s opinion as to the structure of
the vertebrate liver has been recently substantiated by the researches of
Herr Hering. This histologist states that the liver is constructed like the
other secreting glands. It is of the tubular type, with canals, anastomosing
in every direction, and having a tendency to form a series of networks.
Like other secretions, the bile travels along glandular canals surrounded by
glandular cells. It is easy (he says) to observe this arrangement in the
livers of vertebrates. Five or more cells are disposed in simple layers around
the circular and minute aperture of an hepatic utricle seen in transverse sec-
tion. This arrangement loses itself insensibly in that variety of structure
in which there are no utricles properly so called. Occasionally may be seen
four, three, or even only two cells, uniting to form a biliary canal. The
Russian anatomist denies the existence of hepatic trabeculae of biliferous
capillaries, and believes that the biliary cells are persistent. He looks upon
serpents’ livers as the only organs for minute inquiries upon the subject. —
Vide Lancet Record of Science, March 2.

Blood-poisoning after Surgical Operations. — The researches and experi-
ments of M. Maisonneuve prove that nearly 95 per cent, of the sequelae
of surgical operations result from the action of morbid products developed
in the wound, and subsequently absorbed into the system. He puts forward
his ideas in the following systematic fashion : — 1. The blood and other
animal fluids, when exposed freely to the air, or in contact with aqueous
substances, soon lose their vitality. 2. Once dead, they are liable to
putrefy under the influence of heat, moisture, and air. 3. The products of
such putrefaction are highly poisonous. 4. It is the same with such secre-
tions as the urine, bile, and intestinal juices. 5. In infiltrating the permeable
tissues with which they are in contact, these poisoned liquids give rise to
gangrene, erysipelas, &c. 6. These same liquids, either by themselves or

mixed with the special products of inflammation they provoke, can, in
entering the circulation, alter the blood and disturb important functions.
7. After their expulsion from the general blood-vessels, they may remain in
the capillaries, the parenchymata, serous tissues, &c,, and give rise to abscess,
anthrax, &c. 8. The entirety of the disturbances constitutes surgical fevers.

To prevent these terrible consequences of operations, M. Maisonneuve sug-
gests the adoption of the subcutaneous method, and the employment of Ml
means of preventing putrefactive processes.

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The Cause of Colour-blindness. — In a paper, published in one of the
American Medical Journals, Dr. M. A. Fallen states that this condition is
divided into two classes, viz., Achromatopsy, or an insensibility of the eye
to colours, and Dischromatopsia , which is a species of insensibility to colours.
Of these, one is hereditary: the other is acquired and often subjective. Dr.
Pallen believes that the colour-blindness depends upon some abnormality of
the vitreous humour, whose function he believes to be the correction of
prismatic refraction. It is well known that the vitreous humour is com-
posed of a great number of irregular-shaped compartments, containing
gelatinous-like fluid. These cells are separated by septa, and it is the
disturbance or abnormal condition of these septa to which Dr. Pallen attri-
butes the irregular refraction which gives rise to colour-blindness. — Vide
The British Medical Journal, March 16.

Intermittent Fevers produced by Vegetable Organisms. — Some time since,
we called attention to Dr. Salisbury’s observations, tending to support the
theory expressed above. More recently, these ideas have been, in some
measure, confirmed by Professor Hannon, of the University of Brussels. In
1843, says M. Hannon, 11 1 studied at the University of Liege ; Professor
Charles Morsen had created in me such an enthusiasm in the study of the
fresh water algse, that the windows and mantlepiece of my chamber were
encumbered with plates filled with vaucheria, oscillatoria, and confervse.
My preceptor said to me : ‘ Take care at the period of their fructification,
for the spores of the algae give intermittent fever. I have had it every time
I have studied them too closely.’ As I cultivated my algae in pure water,
and not in the water of the marsh where I had gathered them, I did not
attach any importance to his remark. I suffered for my carelessness a month
later, at the period of their fructification. I was taken with shivering ;
my teeth chattered; I had the fever, which lasted six weeks.” — Ibid.
February 23.

Hyposulphites in Dysentery. — M. Paul records some cases of dysentery, in
which great relief was given to the patient by the injection of solution of
hyposulphite of soda. This substance also completely removed all smell. —
Vide Bulletin de Therapeutique.

Quantity of Bed Globules in the Blood. — Signor Mantegazza, of Pavia, has
undertaken a number of researches on this subject. Having constructed a
new form of instrument for estimating the number of the red corpuscles, he
arrives at several important conclusions, of which the following are a few
1. The maximum number of red corpuscles in the blood of a healthy man is
5,625,000 per cubic millimetre of blood ; the minimum (found in the blood
of an anoemic woman) being 2,250,000 in the same volume. 2. The colour
of the face and lips does not indicate the presence of a large proportion of
red globules in the blood. 3. Urea, injected into the veins, rapidly
diminishes the quantity of blood globules, in seven days reducing the
number to about one-fifth of the usual quantity. 4. The proportion of the
corpuscles in rabbits is nearly the same as that of man. 5. The foetal
rabbit has a larger proportion of red corpuscles than its parent.

Medical Products of the Pine. — It is stated, by the Chemical Neivs , that
these products are now being much used in Paris. We cannot vouch for
the reported therapeutic importance of these substances, but, as it may

SCIENTIFIC SUMMARY.

221

interest our readers, we quote our contemporary’s observations: — ^Vege-
table wadding preserves all the properties of the pine ; it evolves an aroma
eminently wholesome. Dr. Schillbach recommends it as a most harmless
but efficacious remedy in cases of catarrh, bronchitis, asthma, sore throat,
etc. Raw vegetable wool is one-half cheaper than the ordinary wool
mattresses. Those stuffed with this wool do not attract humidity; its
odour and the ozone, due to its resinous principles, keep off or kill the
insects. Schmidt-Missler’s flannel, by reason of the resin, the tannin, and
the formic acid it contains, aids the exercise of the important functions of
respiration, absorption, and perspiration, in a greater degree than ordinary
flannel. It is, at the same time, a preservative and corrective agent, which
merits to become popular in Europe, as it is in Germany, and can be woven
into any of the forms for which flannel is used, such as mittens, waistcoats,
drawers, socks, &c. Etherated pine-oil, employed in friction, has given un-
expected results ; in the first commencement of paralysis and apoplexy, in
the case of recent bums, etc.”

The Formation of Cells in Animal Tissues. — This long-debated question
does not appear likely to be answered satisfactorily by the recent researches
of Dr. E. Montgomery. Dr. Montgomery lately presented a paper to the
Royal Society on the above subject, and in it he endeavoured to prove that
the formation of the animal cell is purely a physical process. This he
believes to have demonstrated experimentally. The following experiment
is the one which most strongly supports his opinions : — u When to myeline,
in its dry amorphous state, water is added, slender lubes are seen to shoot
forth from all free margins. These are sometimes wonderfully like nerve-
tubes ; they are most flexible and plastic. From this curious tendency of
shooting forth in a rectilinear direction, it was inferred that a crystallising
force must be at work. To counteract this tendency, and to oblige the
substance to crystallise into globules, it was intimately mixed with white
of egg. The result was most perfect. Instead of tubes, splendid clear
globules, layer after layer, were formed, resembling closely those of the
crystalline lens formed under similar conditions. The remaining task was
comparatively an easy one. By mixing the myeline with blood serum,
globules were obtained, showing the most lively molecular motion. — Vide
Proceedings of the Loyal Society.

The Arrangement of the Lymphatics. — In a note presented to the French
Academy M. Robin described the appearance of the lymphatics in Torpedos
(animals which are admirably adapted for researches on the lymphatic system).
In this class of fishes generally the network forming the origin of the lymphatics
are directly applied against the capillary blood-vessels. Concerning the
section of a capillary, the lymphatic vessel forms a canal which embraces
one half, two-thirds, or even three-fourths of the circumference of this
vessel. The lymphatic, in fact, represents a canal which has a proper wall
only on one side ; for the rest of its extent it is bounded by the capillary —
at least, the proper coat of the lymphatic adheres so to the capillary that it is
impossible to distinguish this portion of it. Thus it may be seen that the
lymphatic vessels are closely applied to the capillary vessels, and the same
position is observed as regards the larger arterial vessels also. From the
numerous anatomical facts which he adduces, M. Robin is led to conclude

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that the chief use of the lymphatics is to charge themselves with the excess
of that portion of the blood plasma which reaches and issues from the capil-
laries at each beat of the heart. — Vide Comptes Bendus , January 7.

The Brain of the Cuttle-fish. — Mr. Lockhart Clarke, F.R.S., has published
a valuable memoir on the optic lobes of tb e cuttle-fish. In this he gives a
general account of the brain of this creature. The brain, he says, consists of
several ganglia closely aggregated round the upper part of the oesophagus.
The foremost or pharyngeal ganglia, which is much the smallest, is bilobed,
and somewhat quadrangular. The next is a large bilobed ganglia, which
forms the roof of the canal for the oesophagus. Beneath the oesophagus is
another large and broad mass, which is connected on each side with the
supra-oesophageal masses by bands that complete the oesophageal ring.
From each side of the cephalic mass springs a thick optic peduncle which
ends in the optic lobe. Strange to say, each optic lobe is larger than all the
other cerebral masses taken together. It resembles the human kidney. “It
is completely enveloped in a thick layer of optic nerves, disposed in flat-
tened bands which issue from all parts of its substance, and pierced to the
back of the eye in a fan-shaped expansion, the upper and lower bands cross-
ing each other in their course. The substance of each lobe consists of two
distinct portions, which differ from each other entirely in appearance. The
outer portion resembles a very thin rind or shell, is extremely delicate, and
is very easily torn from the cerebral substance which it encloses. It con-
sists of three layers — an external, an internal, and a middle pale and
broader layer, containing thin and concentric bands of fibres.

The Accoucheur's Air-pump. — M. Kaufmann says that the difficulties of
parturition are often caused by the existence of a vacuum, which prevents
the expulsion of the child. He therefore proposes to employ an air syringe
with which to prevent so unfortunate an obstruction. This will no doubt
astonish some of our medical readers.

Tobacco Smoking Injurious to the Eyes. — In a recent number (February
15) of the Bulletin de Therapeutique , M. Viardin describes two cases of
serious eye affection (Amblyopia) resulting from the habit of smoking.
M. Viardin at once, on learning the habits of the patients, induced them to
smoke a much smaller quantity of tobacco than usual, and the result was
a complete restoration of vision in a few weeks from the date of their
application.

Ergotine after Operations. — M. Labat asserts that ergotine should be
given after every surgical operation. He says that if completely prevents
the development of morbid products likely to be detrimental.

Action of the Curara Poison on the Human Body. — When not given in
absolutely poisonous doses, the effects of curara on the human system are
peculiar, and have been quite recently studied by MM. Voisin and Liouville.
The therapeutic effects appear to be twofold, according to the dose adminis-
tered. The doses producing these effects vary from 5 centigrammes to 135
milligrammes. In these doses the substance was administered (after filtra-
tion) by subcutaneous injection. The rapidity of the appearance of the
effects and their intensity were proportionate to the dose. They have been
divided by the authors into two categories. The first of these is charac-
terised by a disturbance of vision, a sense of weight in the eyelids, which

SCIENTIFIC SUMMARY.

223

are kept half closed, and a feeling of obstruction in the frontal region. The
second is characterised by diplopia, dilatation of the pupils, and subsequent
heaviness of the head, tending to sleep and drowsiness. The second effects
are produced by doses of from 5 to 9 centigrammes, and the first by doses of
from 10 to 135 milligrammes.

Influence of Respiration on the Circulation. — Dr. Burdon-Sanderson, who
delivered the Croonian Lecture at the Royal Society on March 7, put
forward opinions relative to the influence of the respiratory movements over
the movement of the blood in the great vessels, which are different from
those stated in most of the existing text-books on physiology. Dr. San-
derson stated that so long as the air passages are open, each expansion of
the chest is followed by increase of arterial tension, so that the effect of
inspiration is to increase alike the pace and frequency of the heart’s contrac-
tion. When, however, the respiratory apertures are closed, as in suffoca-
tion, the relations are reversed, the pressure in the arterial system being
then highest in expiration, and vice versa.

MICROSCOPY.

A Diaphragm Eye-piece. — This ingenious and .useful contrivance, the
invention of Henry J. Slack, Esq., F.G.S., has been lately described to the
Microscopical Society. Mr. Slack found that in viewing small objects by
transmitted light, it frequently happens that there is such a large field of
light external to the object, that not only are small details of structure
obscured, but the eye is wearied by the influence of the luminous stream. To
prevent this he requested Mr. Ross to adjust four movable shutters, so
that an A eye-piece might be susceptible of all the changes in the form and
size of its field that different objects would require. This change was soon
effected. Mr. Slack has, therefore, provided microscopists with an eye-
piece which will be found useful in research, and will tend to protect the
eye from the injurious influence of the stream of bright light which usually
falls upon it.

Wire-spring Clip. — Those who have used Dr. Maddox’s wire-spring clip
will be glad to learn that an improved form of it was exhibited by Mr.
Jabez Hogg some time since, at a meeting of the Microscopical Society.
It differs from the original form in having the point, which presses on the
covering-glass, protected by a little disc of leather. The advantages of this
addition are manifold. The pressure of the spring is distributed uni-
formly over the covering-glass, and this latter is therefore not only less
likely to be broken, but less liable to disturbance from its proper position.
They are sold by all makers. Those we have seen were shown us by Mr.
Charles Collins.

The Amateur's 11 Mounting ” Case. — This is a case prepared by Mr.
Collins, of Great Titchfield Street, and of which we give an illustration.
It is intended for the use of those whose microscopic pursuits are of a
general character, and is, so far as we can see, admirably adapted to the

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purposes for which it is devised. It consists of a handsome polished deal
case, with lock and key, and is divided in to several compartments, in which
are placed all the appliances required by the general microscopist. To enu-
merate the contents would be useless, but we may mention some of the
apparatus supplied. These are: A spirit lamp, mounting table, turning
table for cells, a set of wire-spring clips, bottles containing all the fluids
(balsam, turpentine, gold size, &c.), tin cells, ground-glass slides, thin
covering glass, &c. The whole case is so compact, so ingeniously
arranged, and so full of all the materials required in mounting objects, that
we have no doubt it will meet with the approval of our readers.

THE AMATEUR’S “MOUNTING” CASE.

The Student's u Mounting ” Case. — This case has been prepared by Mr.
Collins at our suggestion, and we venture to think that it will meet the
wants of those who are engaged in the study of animal tissues. The
study of human histology is so different from that in which most micro-
scopists are engaged, that it requires a set of contrivances and apparatus for
investigation quite distinct from those generally employed in microscopic
observation. The student is often at a loss to know what appliances he
requires for his researches, and not unfrequently when this first difficulty is
surmounted, he is ignorant as to where he may procure these appliances ; this
last obstacle, being enhanced by the fact that he must go from one optician’s
to another to get together his materials. Finally, he must bring a pre-
scription to a chemist for his injecting fluids. Now, we know, from our
own experience, that the earnest medical student has very little leisure at
his disposal, and we have therefore caused to be put together the several
fluids and instruments which we believe to be essential to his microscopical
inquiries. The woodcut to some extent shows the nature of the new case,

SCIENTIFIC SUMMARY.

225

which is a square polished deal box, with lock and key. The two large
bottles to the right contain the blue and scarlet transparent injecting-
fluids, recommended by Dr. Beale, and which we have found extremely
useful. The smaller bottles contain glycerine, marine glue, asphalt, Dean’s
fluid, balsam, turpentine, chromic acid, carmine fluid, bichromate of potash,
solution of caustic potash, and acetic acid. The two latter bottles are pro-
vided with stoppers which project nearly to the bottom, and thus enable the
student without loss of time to obtain a drop of the reagent he requires. Most
of the other bottles, too, have projections from their stoppers for a like purpose.
In the lower part of the case is seen a syringe, with stop-cock and nozzles,
glass slides, razor in fixed handle, Maddox’s spring clips, covering-glass, tin
cells, American letter clips (for stopping up vessels), curved needles, silk, &c.
Of course it is quite possible that, in very complex investigations, other ap-
paratus than those mentioned may be required ; but we think that, for all
the purposes of ordinary investigation, the student will find all that he wants
in this case.

The Travelling Microscope . — Mr. Moginie, of the firm of Messrs. Baker of
Holborn, has just devised the microscope represented in p.226, and they term •
it the travelling microscope. It is intended to be placed in the telescope case
(in the cut) and to be slung upon the shoulders like a field glass. The three
legs form a solid firm support, and being hollow in the interior are employed
to contain dipping tube, &c. The rough adjustment is telescopic, but the fine
adjustment is provided for by a spring and screw placed on the upper part of
the central or largest leg of the tripod ; this adjustment, so far as we have
seen, is uniform and efficient. When it is required to place the microscope
in the vertical position, three smaller legs, enclosed in one of the tripod legs,
come out, and may be screwed into the instrument, producing a tolerably

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POPULAR SCIENCE REVIEW.

firm foot. There is a small mirror and stage. The instrument is provided
with the universal screw, so that the objectives of one’s usual microscope may
he attached to it.

THE TRAVELLING MICROSCOPE.

An ingenious Pond-stick , which will be found very useful by those engaged
in collecting infusoria, &c., from ponds, has been constructed by Messrs. Baker.
In appearance it resembles an ordinary walking-stick. When the ferrule is
unscrewed a second stick may be drawn out from within the first, thus
doubling the length. To the end of this is attached a brass ring, and into this
can be screwed a dipping bottle. These bottles may be had of various sizes,
and as the glass neck is worked into a screw they can readily be attached to
the ring.

The MicroscopisT s Air-pump. — Most of the air-pumps in use by micro-
scopists are large, inconvenient, and expensive. Mr. Baker has, however, con-
structed one which is especially intended for the preparation of microscopic
objects, and which appears likely to prove useful. Beneath a solid table is
fixed the pump in the form of a brass syringe. This communicates by an
aperture with a smooth metallic plate fixed on the table. When required
for use the object is laid on this plate and is covered with an oblong glass
box whose edges are ground and greased (being thus rendered air-tight).
The syringe being now worked, the air is rapidly removed. The plan was
devised by Mr. W. Moginie.

SCIENTIFIC SUMMARY,

227

PHOTOGBAPHY.

Sun- Painting in oil colours. — Mr. Pouncy of Dorchester read a paper under
this title at a recent meeting of the Inventors’ Institute, wherein he de-
scribed certain improvements in his process of permanent printing in photo-
graphy calculated to widen its sphere of application, and give it more
practical value and interest. The sensitive medium used, is that first intro-
duced in connection with photographic experiments, viz., bitumen of Judea,
which is dissolved in turpentine, or benzole, with which pigments ground
in oil are mixed so as to produce any given colour, tint or shade. Brushed
over a thin sheet of translucent paper and dried in the dark-room it is then
exposed to the action of natural, or some powerful artificial, light under a
negative, until the actinic influence renders the parts to which it has had
access in various degrees proportionate to its degrees of action insoluble in
the original solvent, the application of which of course produces the picture.
This is then transferred by pressure in a lithographic press to cardboard,
canvas, wood, stone, or when ceramic colours are used by hand pressure only,
to potter’s “ biscuit” and burnt in. Mr. Pouncy illustrated his paper with
a great variety of specimens and went through the different manipulatory
processes with great ease and certainty.

The Latent Image. — We have chronicled from time to time experiments
intended to demonstrate the true nature of the photographic image, and last
did so in connection with the efforts of Mr. Carey Lea published in The
British Journal of Photography. A well known French experimentalist,
M. Davanne, writing upon the theoretical researches of the above-mentioned
gentleman (and those of Major Eussell and MM. Poitevin and Vogel) says
although Mr. Carey Lea has certainly cleared up one important controversial
point, viz. the sensitiveness of iodide of silver, when pure, to the action of
light, yet he has done nothing calculated to show definitely whether the
latent image is due to purely chemical or to purely physical action, and adds
“ In presence of light the iodide of silver discovers a tendency to lose a por-
tion of the iodine, especially where it is connected with a body which is
capable of absorbing it. It seems therefore that light not only modifies the
physical condition of the iodide, but brings about its chemical decomposition,
having determined the elimination of iodine. ” M. Davanne is therefore
strongly inclined to attribute the formation of the photographic image rather
to chemical, than to physical conditions. In connection with this subject he
also asks those who uphold the physical theory, how they explain a curious
fact recently made known to him by M. Magny, who having put aside a
negative as useless, from its want of detail in the less exposed portions of the
plate found after it had been in darkness for about six months, that well
defined details had positively become developed by the continued slow decom-
position of the iodide of silver. Commenting on this statement, the Paris
correspondent of the British Journal of Photography says : “ Without
wishing to shirk the question put by M. Davanne, I would suggest that it is
not philosophical to assume that ‘ time can produce the same action as light,’
because, had that plate been exposed to light six months before it was deve-
loped the lines and half-tones would not have appeared, and if it had been

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POPULAR SCIENCE REVIEW.

kept without the action of the developer for six months after the exposure
the lines would have been equally invisible. It was not time, which pro-
duced the image, and I think the question of physical versus chemical action
is in no way touched by the fact. It seems to me that the iodide of silver
on the plate was altered by light so as to he acted upon by the developer ;
that the developing action was not continued sufficiently long under the in-
spection of the operator for all the details to be produced, but the plate being
considered useless was put away with some of the developer adhering to it,
which, acting slowly upon the already altered iodide of silver, gradually
continued the light’s action. This fact proves, I think, if it proves any-
thing, that however weak the action of light may be upon a plate, it may
be rendered visible if you develope long enough.” It is giving M. Davanne
excessively little credit to suppose that he overlooked the above extremely
simple explanation of M. Magny’s u curious fact.” We think it exceedingly
improbable that M. Davanne did not satisfy himself upon the above points
before he plunged into print and asked for an explanation of a very different
nature than that based upon the above assumption.

The Tannin Process . — Better pictures than those produced by the Tannin
process we have not met with. Therefore, in common with most other
photographers, we were grieved and annoyed to read in the Journal of
the Photographic Society an ill-judged editorial article strongly condemna-
tory of the process, sneering at its author, and insulting the many able
and eminent amateur and professional photographers, who practise it. The
following quotation, as a specimen, will, we fear, not convey a very favour-
able impression of its author’s good-nature or impartiality. “ To clear
the ground of rubbish is at all times a step in the right direction. For this
reason the almost total abandonment of the tannin process must result in good.
This process has vexed and irritated photographers ever since its first appear-
ance. The best pictures ever exhibited by it have been of that mediocre class
which pleases none but those most easily pleased. Much time would have been
saved to amateurs if the process had remained in the chaos from which it ap-
parently sprung ! ” The editor of one of our contemporaries says : “We are a
little curious to know how such earnest workers as Messrs. Mathew Whiting,
Le Neve Foster, Jabez Hughes, Warwick, King, Major Russell, and nume-
rous other gentlemen, whose names have been honourably and intimately
associated with the practice of the tannin process relish the impertinences
thus flung at them.” Several gentlemen who were on the Council of the
Society sent in their resignation in consequence of this uncalled-for attack,
protesting against the admission of articles into the Society’s Journal , which
are injurious to its character and to the best interests of the Society; and
a letter from one gentleman whose name was introduced in the article
as antagonistic to the tannin process has been published, in which he says
that he has abandoned every other process and given in his adhesion to the
tannin as the best he can employ.

Hardness as a defect in Photographs , has received attention at a meeting
of the South London Photographic Society in a paper read by one of its
Vice-Presidents, Mr. A. H. Wall, who pointed out that the excessive in-
tensity of the illumination given by a lens must necessarily produce images
very different from those seen by the human eye. The smallness of the

SCIENTIFIC SUMMARY.

229

aperture or pupil, the character of the humours composing the lenses and
the field (or retina) covered, when compared with the photographic lens and
camera, all showed how widely different were the conditions under which
the two kinds of images were relatively formed. Looking at natural objects
with the naked eye and then looking at them as thrown by a lens on the photo-
grapher’s focussing screen was as if the objects had been suddenly conveyed
into a purer and more strongly illuminated atmosphere. The lights, sha-
dows, and colours appeared greatly more intense, minute detail became more
prominently and sharply defined, varieties and degrees of difference in texture
largely disappeared, distant objects seemed nearer; and however charming
the effects thus seen might be on the ground glass, they were productive
of anything but a proper natural effect in the finished photographs. This
was due, Mr. W all believed, to the condensation of an excessive amount of
light by large lenses constructed with a view to accelerating the exposure
of the plate. The remedy Mr. Wall proposed was the adoption of lenses of
longer focus with smaller apertures or stops and with the use of chemicals
and other conditions calculated to render the exposures as short as, under
such circumstances, was possible. A very animated discussion followed the
paper, and various views were advanced, most of them being more or less
favourable to the opinions above expressed.

Mr. Dallmeyer's u New ” Portrait Lens. — This lens is so constructed as to
give its user the option of either producing a sharp image or one softened,
or blurred, by being put more or less out of focus. Some writers have argued
as if this eminent optician, by introducing such a lens, advocated spherical
aberration as an element of artistic success in photographing. We suspect
the simple truth to be that Mr. Dallmeyer only desired to produce a lens
for which there appeared to be a growing demand in the optical market.

Photography and Electricity. — Mr. William H. Harrison informs us that at
the present time more than one philosopher of eminence is experimenting pho-
tographically on comparatively untrodden ground in connection with the rays
thrown out by electricity in passing through vacuum tubes, such rays being
rich in photogenic power.

Photographs of Brass Rubbing. — Mr. 0. G. Rylander has recently giyen
attention to a new photographic application, by which a large number of
copies may be obtained from the rubbings from old brasses, it being his inten-
tion, we believe, to publish them in a volume, for which purpose he solicits
communications from those who may have a collection of such rubbings.
Mr. Rylander’s address is 129 Malden Road, Kentish Town. A brass rubbing
is effected by pressing a sheet of white paper in close contact with the
monumental tablet and rubbing the upper surface with a small cake of shoe-
maker’s u heel ball,” while care must be taken that the paper be not dis-
placed during the operation. By these means the raised parts are blackened
and rendered opaque and the white parts are more transparent. By using
this as a negative on paper sensitive to light, a print is obtained in which
the lines are black on a white ground.

230

POPULAR SCIENCE REVIEW.

PHYSICS.

Changes of Temperature produced by Mixing different Liquids. — MM. Bussy
and Buignet, to whose united researches we have already directed attention
in an earlier number of this Review, have presented a second memoir to the
French Academy, on the above interesting phenomenon. They have arrived
at the following conclusions : — 1. In all the cases under examination, with
one sole exception, the calorific capacity of the mixture is a little superior
to the mean capacity of the elements. 2. By a singular opposition, the
liquids for which the increase of bulk is the most considerable are exactly
those which develope most heat at the moment of their union, such as ether
and chloroform, alcohol and water, sulphuric acid and water. Meanwhile,
the only instance hitherto noticed of a diminution of bulk is the mixture of
chloroform and sulphide of carbon, at the same time the decrease of tempera-
ture taking place at the moment of the union. 3. Independently of the loss
of heat resulting from the changes of volume, there exists a cause which
produces alone an absorption of heat — an absorption which can be sometimes
equal, and even superior, to the heat given out by the combination of the
liquids. — Comptes Rendus, February 25.

Frozen Aerated Waters. — Mr. Tomlinson, of King’s College, who is one of
our most indefatigable students of Natural Philosophy, has written to our
contemporary, the Chemical News, explaining the curious phenomena
resulting from the freezing of water, saturated with carbonic acid. He
gives the following account of one of his first experiments : — During the
recent cold weather I impregnated with carbonic acid, distilled water con-
tained in eight-ounce and other phials, which were then corked and exposed
to the air at temperatures ranging between 23° and 30° F. The first action
of the cold was to produce long needles of clear transparent ice, as thick
as the little finger, occupying aboukthe centre of the bottle, in some cases
parallel with the sides, in others at an angle thereto. The further action of
the cold was to enclose these transparent crystals in opaque ice, to thrust
out the cork and break the bottle. In one case the bottom of the bottle was
forced out ; in others the sides were cracked, and the cracks ran in lines from
top to bottom, nearly parallel with the long axis of the bottle. Opaque ice
filled the neck, and even overflowed, so that the ejection of the cork, the
fracture of the bottle, and the overflow, of the ice, were simultaneous
acts.

New Form of Telegraphy . — An invention for the transmission of despatches
by an automatic electro-chemical method has been devised by MM.
Yavin and Fribourg. Its object is to utilise all the velocity of the current
on telegraphic lines. The Abb6 Moigno, who has called attention to it in
England, gives the following description of it : — It consists in the distribu-
tion of the current through as many small wires, very short and isolated, as
there are signals to be transmitted, all the. while only employing one wire
on the main line. Each of these small isolated wires communicates, on the
one hand, with a metallic plate, of a particular form, fixed in gutta-percha ;
and, on the other, with a metallic division of a disc, which is also formed of
an insulating substance. A group of eleven of those small laminae form a

SCIENTIFIC SUMMARY.

231

sort of cypher, which will give all the letters of the alphabet by the suppres-
sion of certain portions of the fundamental form. “Now,” says the Abbe,
“ suppose rows of these compound characters to be placed on a sheet of pre-
pared paper of a metallic nature, the words of the telegram to be sent are
written on them with isolating ink, leaving the other parts of the small
1 stereotyped ’ blocks untouched. The consequence is that the current is
intercepted at every point touched by the ink, and a letter is imprinted on
the prepared paper at the other end of the line where the telegram is to be
received.”

The Magnetic Polarity of Rifles. — Mr. J. Spiller has lately made some very
interesting observations respecting the magnetic power assumed by rifles.
He finds that all the long Enfield barrels of the arms in the possession of
the volunteers of his company exhibit magnetic polarity as the result of the
violent and repeated concussions attending their discharge in a direction
parallel to the magnetic meridian. The Royal Arsenal range runs nearly
north and south, and the rifles, when in use, are always pointed either due
north or a few degrees towards the west — in fact, nearly in the direction
indicated by a compass needle — so that the repeated shocks brought about
by the explosion of the powder may, Mr. Spiller thinks, be considered
equivalent to so many hard blows from a hammer, which, as is well known,
have a similar effect. Mr. Spiller goes on to say that the magnetic charac-
ter appears to be permanent, which would not be the case if the gun-barrels
Avere of the softest description of malleable iron, and the region of the breech
is, in every instance, possessed of north polarity, since it strongly attracts
the south pole of the compass needle. These effects should not be noticed
at all, or only to an inferior degree, in arms ordinarily fired in directions
east and west ; and I imagine that by reversing our usual practice, if it were
possible, and firing towards the south, the indications of polarity would be
changed.

Electric Guns. — At a late meeting of the Society of Natural Sciences of
Seine-et-Oise, M. He Brettes exhibited a rifle on the Fiobert system, and
Avhich is fired by means of electricity. This new invention, with which the
Emperor appears to be much pleased, has the folloAving characters : — Two
small electric batteries are enclosed in the stock, their conducting wires
arrive at the surface of the breech, and can be put in communication with
the extremity of a platinum wire, which traverses the cartridge. A simple
pressure of the finger upon the trigger closes the electric circuit ; the cur-
rent passes ; the platinum wire becomes at once redhot, and inflames the
powder which surrounds it. The cartridges prepared for the needle gun
carry their own priming, and a shock might inflame them ; the cases are
thus liable to explode, and deprive the troops of their ammunition. With
the new system this danger is impossible. It can, as the expense is trifling,
be easily applied to guns of the ancient model. This ingenious weapon does
not, however, seem likely to come into general use. Though exhibited by
M. He Brettes, it was invented by M. Trouve. — Tide French Correspondence
of Chemical News.

Elongation of Electric Conductors. — Mr. E. Edlund has noticed a very
interesting phenomenon in connection with the passage of an electric cur-
rent along a wire conductor. He has found that when a current is passing
VOL. VI. — NO. XXIII. S

232

POPULAR SCIENCE REVIEW.

along a wire, that this latter becomes elongated to a greater extent than
would he explained by the increase of temperature in the wire. This is his
mode of experimenting : — Taking a wire the amount of whose expansion by
heat is known with perfect exactitude, a current is passed through, and the
elongation of the wire is measured ; if its temperature at the moment be
known, it will be seen whether its elongation is in accordance with this
temperature, or is greater. In order to estimate the temperature, M. Edlund
measures the electric conductivity of the wire, and having arrived at this he
deduces the temperature from it. This process of investigation always
proves that the temperature is lower than would explain the elongation of
the wire. Hence he concludes that the elongation is not the result of heat.
It must therefore be produced by the passing currrent. — Vide PoggendorfF s
Annalen , No. 9.

The Physics of the Fire-damp Indicator. — One of the latest forms of Mr.
Ansell’s Fire-damp Indicator is thus described by a contemporary : — It con-
sists of an iron funnel, provided with an iron U-tube, the end of which is
closed by a piece of glass tube, fixed in brass, to which one pole of a battery
is attached ; the upper part of this glass tube carries a brass collar, through
which passes an adjusting screw, to the lower end of which is fastened a
piece of copper wire with a platinum point. Mercury is poured into the iron
funnel till it rises in the glass tube to a convenient height. This mercury is
allowed to find its level by the opening of a valve, when setting the instru-
ment. The septum is a tile of Wedgwood’s ware, and closes the open part
of the funnel, good sealing wax being the best cement for securing it in its
place. The other battery wire is connected with the instrument, so that, if
diffusion take place, the mercury is pressed up against the platinum point,
and thus communication is established. Mr. Ansell has found that this in-
strument gives warning in four seconds, if the mixture of gas be still below
the point of explosion ; but, by adjusting the point so that there is not more
than the thickness of a shilling between it and the mercury, a dangerous
irruption may make itself known in two seconds.

A Cheap and Ingenious Ice Machine. — M. Tonelli, says the Abbe Moigno
has just devised an ice-making machine which bids fair to become very
popular in this country, since it is convenient, cheap, and efficient. The
inventor calls it the “ glacier roulante .” It is a simple metallic cylinder
mounted on a foot. The salt of soda and the salt of ammonia are added
in two operations, the smaller cylinder containing the water to be frozen
is introduced into the interior, and the orifice is closed by an india-
rubber disc, and then by a cover fastened with a catch ; the cylinder is
then placed in a sac, or case of cloth, and it is made to roll on the table
with a slight oscillatory movement given by the hand. After a lapse of
ten minutes, the water in the interior of the cylinder becomes a beautiful
cylinder of ice. Nothing is more simple, more economical, or more effica-
cious than the new u glacier roulante ,” which costs 10 fr., and gives us,
moreover, what could not hitherto be obtained with an apparatus containing
freezing mixtures — the means of freezing a decanter of water or a bottle of
champagne. The apparatus, in a case, packed for travelling, with 20
kilogrammes of refrigerating materials and a measure, costs, at present,
only 1/.

SCIENTIFIC SUMMARY.

233

A New Meteorite. — It is stated that some very large and heavy meteorites,
which fell during last summer in Hungary, have been recently examined.
The circumstances under which the fall occurred are interesting, the sky
being quite clear, between four and five in the afternoon. At the time of the
fall, a violent detonation was heard, similar to that produced by the simul-
taneous discharge of a hundred cannons. The meteorites appeared as a
greyish cloud, about the size of the sun’s disc, uniting on all sides columns
of greyish smoke, but without a trace of luminous appearance. Two or three
minutes after this appearance, a noise was heard like that of a multitude of
stones rattling together ; this lasted for ten or fifteen minutes, and, after it, the
fall of stones took place. Several eye-witnesses, at localities six to twelve
Austrian miles distant, describe the meteor as having presented the appearance
of a yellow and orange luminous globe, followed by a train bordered with
ultramarine blue. About sixty stones were collected, and were found to pos-
sess the usual characters of meteors, being covered also with a layer of black
enamel. The heaviest of these weighed 550 lbs. ; it was broken in two by
the violence of the shock, and from the violence with which it fell to the
earth, it passed into the soil to the depth of about eleven Austrian feet, in
this way forming a hole or pit nearly four feet wide. At a temperature of
20° Reaumur, they had a specific gravity of 3-520. When first found, the
meteorites were quite hot, and some of them retained their heat for several
days.

The Detection of “ Tears ” in Lenses. — The presence, in lenses, of spots of a
different refracting power from the rest of the lenses, is a serious difficulty in
optical experimentation. It is, therefore, interesting to know that Herr A.
Topler has discovered a very useful method of detecting these portions
[tears] in lenses. The mode which this physicist adopts is as follows : — The
light proceeding from a bright lamp, through the aperture of a small shade,
falls upon a system of lenses, which should be as achromatic and aplanatic as
possible. The transmitted light concentrates in a focus, at a distance of from
ten to twenty-five feet on the other side. A simple Keplerian telescope of
two lenses is so set up that its optical axis coincides with that of the system
of lenses above mentioned, and that the focus of the rays issuing from the
system of lenses lies in front of the object-glass of the telescope. The tele-
scope, moreover, is so drawn out that the rays issuing from the eye-piece
have their point of junction at the pupil of the eye, and hence project on
the retina the image of an uniformly illuminated field of view. If a screen
be laterally pushed in front of the object-glass of the telescope, as soon as
its edge passes by the place of the focus the field of view will at once be-
come dark ; if, either in the glass of the system of lenses in question, or in
media which are placed before or behind it, there are places of different
densities ; some rays will, therefore, be deflected from their path — they will
not pass through the focus, and hence will not disappear when the screen is
pushed across. These rays then give an image of the u tears ” in the dark
field of view.

The Optical Analysis of Sound. — Herr A. Topler has pointed out an im-
proved method of analysing vibrations by an optical method. We cannot
here give any adequate explanation of the principle on which his apparatus
is employed. We, therefore, commend the reader to the author’s paper on

234

POPULAR SCIENCE REVIEW.

the above subject. It will be found in the Philosophical Magazine for
January.

Standard Thermometers. — Perhaps there is no instrument which it is of
more importance to the meteorologist to have perfectly corrected than the
thermometer ; yet we learn, from a letter recently addressed to the Times ,
by Mr. H. 0. Kay, that even among the instruments of the first London
makers there is a great want of uniformity. A correspondent of the Chemical
News, writing upon the same subject, corroborates Mr. Kay’s remarks.
Two years ago, he required a first-class maximum registering thermometer
for scientific purposes, and he applied to Messrs. Negretti and Zambra for a
standard instrument, with the Kew certificate. Not having one of them at
the time, they sent him one of the instruments with Mr. Glaisher’s certifi-
cate, which stated that the u reading ” was 05° too high throughout the
range. Some time after, suspecting that the difference was greater than
was represented, he made a comparison with some of the Kew certificated
instruments, and found the following result : —

Kew instrument,
degrees.

574

704

79

Mr. Grlaisher’s instrument,
degrees.

59

72

. . 81*

We draw attention to these facts, because they are of serious importance.
We trust, therefore, that some arrangements may be come to by which only
one certificate shall be allowed, and which shall compel all standard ther-
mometers to be registered.

Vapour Density. — There is now being given a good deal of attention to
this subject, especially upon the Continent. M. Deville, who, as well as
M. Cahours, has given it especial consideration, considers that the objections
which many chemists have to admit that the equivalents of elements and
compounds correspond to one and eight volumes, being grounded on ana-
logies, are supported by little better than gratuitous hypotheses. He has,
in conjunction with Troost, taken the vapour density of NH4I,HgI at 350°
and 440°, and obtained the numbers 6-49 and 6‘38, the density calculated
for eight volumes being 6-44.

ZOOLOGY AND COMPAEATIYE ANATOMY.

A new Rotifer. — The Microscopical Journal, in its analysis of foreign me-
moirs, often supplies us with valuable and interesting information. Not the
least important of the matters recorded in its last chronicle is that which
refers to the discovery and description of a new rotifer by Herr Elias Mecz-
nikow. This observer states that when examining the under surface of some
leaves of the Nymphcea lutea at Giessen he discovered a number of white
lenticular bodies, which proved on examination to be forms of a new species
of rotifer. The adult form of this remarkable species appears when expanded
to consist of two nearly equal circular sacs, the anterior of which is open,
forming the mouth, and is destitute of any wheel apparatus ; it possesses at

SCIENTIFIC SUMMARY.

235

the same time a mastax, well-marked water-vessels, and reproductive organs.
The young female differs totally from the adult in the possession of a ciliary
apparatus, distinct eyes, and also in its free habit of life. The adult male
is, as in other rotifers, quite unlike the female. He has a broad ciliated oval
extremity, provided with eyes, and apparently a large prse-oral ganglion,
while his body gradually tapers to a point posteriorly provided with a few
cilia.

New Myriapoda. — Sir John Lubbock, in a paper read before the Linneean
Society at a late meeting, described a new genus of myriapoda, which he
thinks ought to be the type of a new order of this class. It is called Pau-
ropus, from the circumstance that it possesses far fewer legs than its fellow
genera. The author of the paper met with two species, P. Huxleyi and
P. pedunculatus. The first is the type of the genus : it is about — of an inch
long. It occurs in considerable numbers among dead leaves and in other
accumulations of decaying organic substances. Though not exactly sociable
in its habits, it exhibits none of that extreme ferocity which characterises the
chilopoda. It is very abundant in the author’s garden at High Elms. Sir
John Lubbock wonders how it has been so long overlooked, but attributes
it to the fact that its small size and few legs give it the appearance of some
insect larva. The characters of Pauropus we cannot afford space for, but they
deserve attention, for they are peculiarly exceptional and serve to show that
Pauropus is allied to the Crustacea.

The Fishes of the Amazon. — The district of the Amazon appears to swarm
with all forms of organic life. Of the land animals a very able and graphic
account has already been given by Mr. Bates, and now Professor Agassiz has
given an account of his elaborate investigation of the fish of the Amazon.
In a lecture delivered quite recently at New York, Professor Agassiz stated
that he found that the Amazon has not one fish in common with any
other fresh-water basin ; that different parts of the Amazon have fishes
peculiar to themselves ; and, as an instance of the teeming variety that exists
in the Amazon basin, he gave the result of his examination of a small con-
tiguous lake or pool, of only a few hundred square yards, which showed
!200 different kinds of fishes, which is three times as many as the Mississippi
liver can boast. In the Amazon itself he found 2,000 different kinds, and
when he began his investigation of the river only 150 were known to exist,
and he said that in proportion as he found the larger number the difference
between them seem to grow. He proceeded to a general classification of the
fishes of the Amazon, and instanced one that might appropriately be called
a very peculiar fish, inasmuch as it had the power of walking or creeping on
dry land, one having been foimd five miles from the water, and the Professor
himself kept one of them out of water half a day, and on putting it back
into its natural element it showed as much of life as if it had never been
removed. Moreover, it is an agile fish, worming its way up the inclined
plane of the trunk of some old tree that had fallen, and twisting about
among the branches, until finally a single shot has brought down a bird and
a fish together. Professor Agassiz declared that the Amazon, for a river of
turbid water and of so high a temperature, the average being 80 deg., nou-
rishes an extraordinary number of delicious fishes for table use.

Influence of Development in the Production of Pace. — M. C. Dareste has just

236

POPULAR SCIENCE REVIEW.

presented a memoir to tlie French Academy in which, he endeavours to
prove that monstrosities, errors in development, may become the starting-
point of new races. We do not know whether the learned author is strictly
correct in stating that monstrosities are perpetuated in races. If, however,
he means that natural variations become the starting point of new races he
is merely following in Mr. Darwin’s steps. Vide Comptes Rendus , March 4.

The Production of Male and Worker Bees. — M. H. Landois has presented,
a most interesting note, on this subject, to the French Academy [March 4],
This we translate in part. It is generally supposed, according to the
observations of Dzierzon and Von Siebold, that the worker bees spring from
eggs, fecundated by the queen that lays them, through the medium of the
fluid in her receptaculum seminis ; whilst the male bees spring from unfe-
cundated eggs. Siebold argues, especially, that the presence of zoosperms
in the ova of the worker bees, and their absence in those of the males
proves that, in bees at least, the formation of the sexes depends on fecunda-
tion. But, says M. Landois, u the eggs from which the worker bees are
hatched are placed in very different cells from those in which the eggs from
which the males spring are laid. Hence arises the question, Could we, by
placing the worker eggs in the cells of the male eggs, cause these eggs to
be hatched into males P I have made this experiment on several occasions,
at first unsuccessfully, because the bees defeated my efforts by restoring the
eggs to their original positions ; but afterwards with perfect success. I was
surprised to see worker bees hatched from the eggs that would otherwise
have been males, and males from those which would have been workers.”
This fact he proved repeatedly, and he, therefore, concludes that the sex of
the insect depends, not upon fecundation or non-fecundation, but upon the
conditions under which it is hatched — the food on which it is fed.

The Organs of Parturition in the Kangaroo. — The relations of these parts
which were described by Sir Everard Home, in 1795, were re-described by
Professor Owen, and by M. Ed. Alix. The latter, in a memoir published
some year or eighteen months since, alleged that Sir E. Home’s assertion of
an aperture, leading from the parturition channel to the cloaca, was correct.
This statement, however, was contradicted by Professor Owen, in a com-
munication to the Comptes Rendus. In the Comptes Rendus , January 15,
M. Alix re-asserts that such a condition of parts exists, and he denies that
Professor Owen and Cuvier are correct.

The Structure of the Heart in Fishes of the family Gadidce. — M. Jourdain,
who has made a great number of dissections of the hearts of these fishes,
shows that the heart of the Gadidae is an exception to the general rule in
fishes. Like the heart of the Batrachian, it is devoid of the vascular
element. Extremely fine injections, which were so thoroughly forced along
the arteries as to return by the veins, failed to penetrate the walls of the
ventricle or the auricle. The aortic bulb alone was found to possess a few
slender branches, and these did not extend to the heart properly so-called.
These arterioles are derived from the hyodean artery, and the veins open
into the hyodean vein. To this absence of vessels in the heart corresponds
a peculiar structure of the ventricular walls analogous to that seen in
Batrachia. The muscular fibres, instead of forming a dense tissue^ are
arranged in bundles, and have a series of spaces or trabeculae, which consti-

SCIENTIFIC SUMMARY.

237

tute a sort of areolar or spongy tissue. What is the object of this P It is a
substitute for capillaries. At each dilatation of the ventricle, the blood
rushes into all these irregular cavities, thus providing for the nutrition of
the muscle ; whilst, at each contraction, it is as rapidly expelled.

The Development of Amphioxus Icinceolcitus has been well described by
Herr A. Kovalevsky, in a paper in the Archives des Sciences, and which is
translated in the Annals of Natural History for January. It would be
quite impossible to give even an abstract of his observations, they are stated
in such a condensed manner, and consist so exclusively of facts. Our readers
are aware how important it is to have the development of this aberrant crea-
ture worked out, and will consult the paper for themselves.

Spontaneous Generation. — M. Donne comes forward once more as the sup-
porter of spontaneous generation, and the opponent of the Pasteur. He
quoted the following experiment in support of his opinions: — I took some
hen- eggs, and, having made a minute aperture, I introduced a needle
previously brought to a red heat, and allowed about a third of the
contents to escape. I filled the cavity thus produced with boiling distilled
water, and closed the aperture hermetically with wax. The eggs were then
left exposed to a temperature of from 17° to 24° centigrade. Five days
subsequently, I raised the wax seal, and, having examined the contents of
the egg, found it swarming with vibriones.” Whence, asks M. Donne,
came the germs of the vibriones P It is impossible to suppose they were
originally in the egg, for M. Donne has shown that in eggs which decom-
pose spontaneously they are not present. It is equally difficult to imagine
that they were introduced in the boiling distilled water. To us (Ed.
P. S. R.) there appears to be this objection to the experiment: — In remov-
ing a portion of the egg-contents, and introducing the water, there was
nothing to prevent the introduction of the atmospheric air, and, therefore,
of organic germs also. See Comptes Rendus , January 7.

One of the causes of Silk-worm Disease. — On the 31st of December, M.
Bechamp stated to the Academy that his experiments during the summer
disclosed one of the sources of silk-worm disease. He took a number of
worms from good healthy eggs, and divided them into two batches. One
of these he fed with carefully dried mulberry leaves, and to the other he
gave leaves highly charged with moisture. He found that all those of the
batch fed with dried leaves passed through their metamorphoses; whilst
those in the other series perished. Hence, he supposes, leaves charged with
moisture to be one of the causes of the silk- worm disease. In those speci-
mens fed on the undried, unprepared leaves, he found the peculiar pebrine
corpuscles abundant.

The Muscular Force of Insects. — M. Plateau, whose various researches on
this subject we have already called attention to, has replied to one of the
objections raised against his comparisons. It will be remembered that M.
Plateau illustrated the enormous relative muscular power of the insect by
contrasting it with the horse. This comparison was objected to on the
ground that the horse has only four legs, while the insect has six. To this
M. Plateau replies, that, of those six feet, only the two front and the two
hind legs are engaged in the maximum effort of traction, the two others
being clearly perpendicular to the direction in which the traction is exerted.
Comptes Rendus, December 24.

238

POPULAR SCIENCE REVIEW.

The Development of the Hydrozoa. — In an important memoir on the struc-
ture of certain of the hydrozoa, Herr Reichert denies that these animals can
he compared with the early phases of the vertebrate ovum. In one of his
tabulated conclusions, he says, “'the comparison of the hollow body of the
hydrozoa to the first stages of development of the organism of the higher
vertebrata undertaken by Huxley, and afterwards by Kolliker, has no
foundation, in fact ; it even proceeds from erroneous suppositions, both as to
the nature and signification of the first foundation of the vertebrate animal,
and with regard to the structure of the body of the hydrozoa.” This is a
very decided assertion on the part of Professor Reichert, and we confess
that we see some difficulty in the way of its acceptance.

The Circulation of Helix Pomatia. — On this point an extremely valuable
paper has been published by Mr. C. Robertson, Demonstrator at Oxford.
Mr. Robertson states that he has proved the existence of a general capillary
system of blood-vessels in this animal. We, ourselves, have not been able
to discern such a condition of parts in Limax maximus. Dr. Robertson’s -
memoir is an important contribution to molluscan anatomy. — Vide Annals
of Natural History , January.

239

VENUS’S FLOWEE-BASKET (. EUPLECTflLLA ).
By De. J. E. GRAY, F.R.S., V.P.Z.S., F.L.S., &c.

IT is a truism that every created object is beautiful when
properly examined. Even the toad has a cc jewel in his
head.” But there are some objects, which from the symmetry of
their form, the neatness of their structure, and the beauty of the
material of which they are composed, attract the attention and
excite the curiosity of the most inattentive. The^Venus’s flower-
basket from the Philippines, which is now to be seen in most of
the shops of the dealers in objects of Natural History and in
almost every collection, is a production that combines all these
attributes of beauty and is admired by all.

The Venus’s flower-basket, Ewplectella , may be shortly
described thus : as a siliceous sponge attached by its expanded
base to some marine body, supported by a skeleton of a
cylindrical tubular form, formed of numerous elongated fibres,,,
consisting of fascicules of very long slender linear cylindrical
spicules, and crossed by similar fascicules of spicules, forming a .
square network which at length is covered by a finer network
of fibres, producing concentric and oblique ridges across the-
outside of the tube, and a broad expanded fringe round the edge
of the upper end of the tubular cavity of the skeleton, and
covered with a network lid formed of bundles of shorter spicula.

The base of the tubular body is surrounded by a beard of
elongated, free, siliceous filaments which have recurved hooks
near the end, and which form a ring of recurved hooks at the
top. See PL xi. and xii.

The tube is generally gradually tapering and bevilled on one-
side at the base, but some specimens are shorter and more
ventricose, and more or less ovate or oblong cylindrical.

The skeleton before it is perfectly formed, merely consists of
a tube formed of longitudinal hoops of transverse fibres without
any lid ; the lid is next developed and at length the frill round the
end of the tube, and finally the oblique and cross ridges formed
of the finer external network, are also developed. The score
of specimens in the British Museum exhibit each of these states,
proving that the absence of the lid or of the fringe or of the
external ridges are not specific characters. The free filaments
VOL. VI. — NO. XXIV. T

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POPULAR SCIENCE REVIEW.

forming the frill round the base of the tube are found in the
youngest and least developed specimens, but they are sometimes
torn away by the dealers who send over the specimens, or
perhaps destroyed in preparing them for the market.

The history of the described specimens shows how gradually
the real structure of a rare object becomes known.

The specimen described by MM. Quoy and Graimard only
consisted of the tube without any base or terminal fringe.

Mr. Cuming’s specimen, described and figured by Professor
Owen, was an adult specimen, with the dilated base, the netted
lid, the fringe round the edge of the tube near the lid, the
external ridges and finely netted outer coat that strengthens the
tube, but it was destitute, or nearly so, of the free filaments
that arise from the roots and surround the lower half of the
tube like a large beard.

Dr. Farre’s specimen, also described by Professor Owen, has
the free filaments at the base well developed and preserved, and
the cavity of the sponge is covered with a well-developed lid.
But this specimen is not perfectly grown ; the fringe round
the edge of the tube near the lid, and the outer netted coat
and the transverse ridges on the outer surface of the tube are
not developed.

It is probable that all these differences only depend on age
and the state of the specimen. But Professor Owen regarded
Mr. Cuming’s specimen as distinct from those of MM. Quoy and
G-aimard, because it had a fringe and netted lid ; and Dr.
Farre’s as distinct from Mr. Cuming’s, because it was destitute
of the fringe round the upper part and the ridges on the outer
surface of the tube.

The lightness, elegance, and rigidity of the tube, give the
idea of a beautiful and complicated piece of lace work that has
been suddenly petrified into a hard and transparent stone.
The interlacing of the fibres of which the tube is composed has
the same appearance as canework of the very different trans-
verse and angular directions of the fibres leaving a round mesh.

Professor Owen well observes to the question put by almost
every one to whom the Euplectella is shown, as to how the
threads could have been so regularly yet intricately interwoven :
“ I have sometimes replied that there has been no such thing
as interweaving in the case ; that no thread as such was ever
laid across another in the construction of the Euplectella ; that
the analogy of human textile fabrics does not apply to this beauti-
ful natural object. In artificial network the several stages of a
complex result must be taken in the succession indicated by
painful aod equal calculation ; in organic lacework different
stages are done at once ; thus it is the Divine work surpasses
that of man’s utmost ingenuity. The threads of the Euplectella

EUPLECTELLA.

241

were not first spun and then interwoven, but were formed as
interwoven, the two processes going on simultaneously, or pari
passu ; but as in the cancellous texture of bone, the plates of
bone are not first formed and then fitted to one another, as in
building a house of cards, but the forming and the fitting go
on together in the course of the molecular growth, I pre-
sume also that in the beautiful object which we call the
Euplectella we have but the skeleton, and that in the living
state the exquisite structure of the flinty framework may be
veiled by the delicate gelatinous enveloping organic tissue.” —
Lin. Trans, xiii. 121.

This common jelly not only developes the beautiful cornu-
copia-shaped vase, but if an accident occurs to it the rent is
darned in a most workmanlike manner, as may be observed in
a specimen which is in Mrs. Gray’s collection.

The skeleton above described, is interspersed with abundance
of stellate spicules of very varying forms which are not attached
to the skeleton itself, but belong to the layer of thin flesh or
sarcode with which it is covered when in a living state. These
spicules are of three distinct forms, and they all have acute tips
to their rays; the first form is the most variable, generally
varying from a simple fusiform spicule to a well made six rayed
one, and sometimes these rays are divided into divergent
branches. A series of these forms is figured in Bowerb. Brit.
Sponges , t. 7, f. 174-187, and the more branched t. 8, f. 188-
189, f. 5, 6. The second kind has only four rays, each of which are
divided at the top into several short diverging rays like claws,
figured also in Bowerb. B. Sponges , t. 8, f. 195, f. 8. The
third kind has also only four rays but these soon divide into a
number of elongated rays which converge together at the top
and form a bell-shaped body, f. 7. See Bowerb. B. Sponges , t. 8,
f. 193-194.

Somewhat similar many-rayed stellate spicules have been
observed occupying a similar situation in the beautiful coral-
like siliceous sponge from Barbadoes, called Dactylocalyx
Panicea , of which there are two or three beautiful specimens
in the British Museum. But the spicules of this sponge differ
from all the forms observed in Euplectella in having the top of
each of the rays furnished with a small knob like the head of a
common pin ; they are also figured in Bowerbank? s B. Sponges ,
t. 8, f. 190-192.

The filaments forming the fibres are very long, slender,
nearly of the same diameter through their whole length, and
most of them have a smooth surface. They are solid, elastic,
and less brittle than one would expect from their hardness, but
this arises from their peculiar composition and external structure.

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POPULAR SCIENCE REVIEW.

This structure is common to these filaments and to all the
silicious spicules of other sponges.

The elegant lightness of the flower baskets, one would think,
must render them very liable to accident, but the strength and
rigidity of their structure offer much more resistance than one
might expect, and that this is the case is proved by the very few
cases of injury that are to be found in the specimens that have
been submitted to my examination. The hooks on the free fila-
ments that form the fringe round the base of the tube and
which diverge in every direction must be a great protection, as
they would catch hold of and tear any sea animal that might
attempt to approach it.

The thin elevated ridges which more or less completely and
regularly encircle the outer surface of the tube, add very
considerably to its general strength, and it is to be observed
that the fringe round the apex of the tube can only be regarded
as one of these transverse ribs that is more regular than the
rest, and placed at the edge of the aperture of the tubular body
to give strength and security to the vase.

Indeed, the more we study the structure, the more one is
struck with the lightness, beauty, and admirable manner in
which it is formed for the purpose of resisting injury.

When the filaments are chemically examined, they are found
to consist of nearly pure silica, mixed with a quantity of animal
matter that has been called kerasote in other sponges. If they
are placed in the flame of a spirit lamp, they become black,,
from the charring of the animal matter, and then split up into
numerous very thin laminae, and if submitted to the action of
the blow-pipe, or charcoal, they form a globule of glass. The
filament is solid and hard. If the long fracture is examined
with a magnifying glass, it will be found to be formed of an
immense number of very thin concentric coats, placed one over
the . other round a centre ; but the coats are best seen when the
filaments are placed over the flame of a spirit lamp, when the
filament splits and the coat of animal matter being burnt, the
coats or layers of siliceous matter separate from each other, and
are easier seen. .

All the perfect specimens that I have examined, have a base
consisting of a thick mass of filaments, which enclose a quantity
of earth and fragments of shells, showing that the sponge grows
on the mud of the sea shore. Mr. Cuming’s specimen shows
this structure in the state in which it is generally brought to this
country, see Linn . Trans, xiii. t. 13, f. 1 & 3. Professor Owen-
calls this root “the apical extremity,” and speaks of it as “the
small end where they (the longitudinal fibres) begin to resolve
themselves; into ;their constituent filaments.”

In the description of Dr. Farre’s specimen, Professor Owen

wM

la^9|

EUPLECTELLA.

243

observes : “ It appears in the first described species that the
fine silky filaments into which the parietal fibres were resolved
at the small end of the cylindroid have been torn or detached
by violence from some other body. The subject of the present
description has been fortunately preserved along with the foreign
body to which it was attached, by the terminal filament ; such
mode of attachment may now be therefore added to the generic
character of Eujplectella as above defined. Further, he calls
the end of the tube next the lid the last or lowest of the
transverse fibres,” adding in a footnote, “ on the supposition
that the Eujplectella hangs dependent from its filamentous
attachment.”

So that he evidently seems to think that the position in which
he figured it on the plate in the Linnean Transactions , with
the widest end of the tube (or base as he called it, downwards) is
the natural position of the sponge in the sea, but he has never-
theless figured it in the reversed position, in the second figure,
in the Transactions of the Zoological Society , that is to say,
with the root-like base downwards, and the wider part of the
tube above. Dr. Bowerbank thinks that “some of them are
apparently of a parasitic habit,” but the specimens lately re-
ceived do not justify such a theory. They all seem to have
lived attached to mud.

M. De Blainville, in his very useful Manuel d' Actinologie,
described a small tubular specimen with short blunt branches
like a stunted shrub, Alcyoncellum gelatinosum , which had
been discovered and brought home by M.M. Quoy and Graimard
during their voyage, a calcareous sponge which they seem to
have forgotten, for no account or figure of it occurs in their work.
They quote De Blainville’s character of the genus literatim,
and apply it to their Corbeil de Venus, to which it has not the
slightest alliance, the one being a calcareous sponge, formed of
a multitude of minute three-rayed spicules, and the other, a
beautiful cornucopia, formed of woven fascicules of hard, brittle,
glass-like fibres, so hard that they will scratch glass.

They could never have compared the generic character
which they extra, cted with their specimens, for the description,
which is as follows, is very characteristic.

“ Corps phytoide subpierreux solidifie par des spicules tricus-
jpides a branches peu nombreuses, cylindrique fistulaire, termine
par un orifice arrondi a parois epaisses, compose de granules
reguliers polygones alveoliformes perces d’un pore a l’exterieur
et a l’interieur.” Blainv. p. 302.

M. Miln e-Edwards in his edition of Lamarck, Animaux sans
Vertebres, placed at the end of the sponges an account of MM.
Quoy and Giaimard’s Corbeil de Venus, and perhaps seeing that
the character that they gave in their work did not fit the

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specimen lie compiled a new character for the genus from the
description and figure of MM. Quoy and Graimard, paying no
attention to the fact that M. Be Blainville had already figured
and described a very different sponge under the name of
Alcyoncellum, so that in fact they were giving the same name
to two very different sponges, a course of proceeding very
puzzling to the student. Dr. Bowerbank, defiant of all the rules
about priority, has chosen to retain the name of Alcyoncellum
to the Corbeil de Venus, though M. Be Blainville had applied
it to the branched calcareous species several years previously.
Professor Owen, when he described Mr. Cuming’s specimen,
properly applied the new name of Euplectella, or beautiful net,
to the genus, but not because of the confusion caused by the
mistake of MM. Quoy and Graimard and M. Milne-Edwards,
which would have been a very valid argument, but because he
and M. Milne-Edwards misread Be Blainville’s name of Alcy-
oncellum for Alcyonella , observing that name had already been
applied by Lamarck to a genus of fresh-water polypes.

Professor Owen had evidently not observed the very decided
difference between the genera named Alcyoncellum by Be
Blainville and by M. Milne-Edwards, for in his paper he speaks
of “ Alcyonellum gelatinosum ” of Be Blainville and “ Alcy-
onella speciosum of Quoy and Graimard as if they were the
same species, instead of two sponges as unlike as it is possible
for two sponges to be from each other.

All this may appear of little importance, but as the great use
of Zoology is to enable the student to record his observations
with accuracy, so that succeeding observers may understand
them, and this can never be carried out if two very different
animals or plants bear the same name, as one observer may be
speaking of one animal and the other of the different one which
has been called by the same name by some other describer.
This has been the source of numberless errors.

The name and synonyms of the species may be tabulated as
follows.

Euplectella speciosa. — Gray, Ann. and Mag. of N. II., 1866.
Alcyoncellum; speciosum. — Quoy and Gaimard, Voy. Astrolabe, Zoophytes ,
302, t. 26, f. 3, 1833, imperfect.

Euplectella aspergillum. — Owen, Trans. Zool. Soc., iij. 203, 1. 13, 1843,
with basal filaments.

Euplectella Cucumer. — Owen, Trans. Linn. Soc. xxi. 117, t. 21, a short
specimen without apical fringe.

Alcyoncellum orbicula and A. aspergillum. — Bowerbank, British
Sponges, vol. i. 117, t. 29, f. 356-357, p. 257.

Mr. Cuming obtained his specimen at the Island of Zebu, one
of the Philippines, and all those that are now in the market
are said to come from the same locality, and I believe that it is
well known that they are sent from Manilla, the capital of the

EUPLECTELLA.

245

Philippine Islands. They may be found in other parts of the
Indian Ocean. MM. Quoy and Gaimard’s specimen was pre-
sented to them by M. Merkus, the governor of the Moluccas and
said to have been taken up by a sounding. Dr. Arthur Farre’s
specimen was presented by the king of the Seychelle Islands
to Captain Etheridge, K.N. and Captain Sir Edward Belcher,
B.N. brought home a very much crushed specimen obtained
during his last voyage, but the habitat was not marked ;
indeed this specimen was picked from among the rejectamenta
of the collection, and seems to have been unobserved when
collected. It is to be observed that it is not decidedly stated
that either MM. Quoy and Graimard’s specimen or Dr. Farre’s
were obtained in the localities where they were given to their
respective owners, and they might have been picked up as
curiosities, and sent from other quarters.

It would be interesting to discover how they have become so
common all on a sudden. The Governor of the Moluccas who
gave the specimen to MM. Quoy and Gaimard and the Governor
of Manilla, to whom Mr. Cuming showed his specimen, each
assured those gentlemen that the specimen was exceedingly rare,
and the two specimens remained almost unique, one orna-
menting the Paris Museum, and the other the collection of
M. Cuming for some thirty years, and then they all at once
became abundant and were sent to market as a regular object
of trade, most of them having been specially prepared by being
artificially bleached.

Many of the specimens have a crab in the base of the tube
and it is a general belief at Manilla that the case is spun by the
crab ; that the male and female crab each forms a tube ; and
therefore they do not consider a single specimen complete
without it has its fellow. This may be only as a ruse to induce
persons to purchase a couple of specimens. The specimens with
a crab in them are valued much higher than those that are
without it ; thus a Spaniard came from Spain with two speci-
mens each containing a crab, and valued them at 400£. be-
cause they had the crabs in them. He was much disgusted when
I showed him that some of those we had in the museum also
had crabs, but he could only answer that in his case there were
a pair, male and female. The crab might easily get into the
tube before the lid is completed and it would then be caged so
that it could not escape. But I am informed that the crabs are
always inserted by the Manilla dealers; that they break the
specimen partially across just above the root and insert the
crab, and then bend the root back again. Since I have been
told this I certainly have observed that all the specimens that
do contain crabs are cracked near the base. At first it was
believed that only one kind of crab, an Isopode, was contained

246

POPULAR SCIENCE REVIEW.

in them, and a French author has promised to write a work to
prove that the flower-basket is made by the crab and is not a
sponge ! But I have seen several kinds of crabs in the different
specimens submitted to my examination and one collecter wants
a large price for his specimen because he says it has twins ;
that is, there are two crabs in the same tube — I believe, of two
kinds.

The history of the Venus’s flower-basket is a good illustra-
tion, showing how completely the price of a Natural History
specimen depends on the rarity rather than the beauty of the
article. Mr. Cuming sold his specimen to Mr. Broderip for
30k and after a time Mr. Cuming bought it back for the
same price as he received for it. This specimen, which is now
in the British Museum, is very much discoloured and not
otherwise in a good condition. About a year ago a merchant
in the city received twelve or fourteen specimens; he was
informed what they were, but he declined to dispose of them
until he received instructions from the person who sent them
from Manilla. About four months ago he arranged with a Natural
History dealer, who undertook to sell them so that he should
receive 10Z. for each specimen. The specimens were scarcely
all sold at prices ranging from 10Z. to 1 51. each, when a few
specimens came into the market, that had been sent from
Manilla to Hamburg. More and more specimens arrived, and
the price rapidly decreased from 71. to 51. and to 3 Z., when a
report was spread that 1,200, that is to say six boxes containing
two hundred specimens each, had passed the custom house and
were in London. The prices kept going down and it is expected
that they may hereafter be sold at 10s. or even 5s. each ; for
a friend from Manilla informs me that they are so numerous in
that town that the hawkers go about with a quantity in a basket,
selling them at one quarter dollar each. However common
they may become, they will always be a most beautiful object
and an ornament to any room that may contain them.

The dealers like such beautiful objects to be rare and dear.
On my mentioning the number that had arrived to one of
them he observed, u I wish I had been present at the examina-
tion, would I not have become suddenly drunk or excited and
stumbled into one or more of the boxes ! ” I think if he had
done so he would have paid for his temerity, for the fragments
of the fibres would have severely punished him and have been
difficult to extract from his skin; the irritation of cowage or
of the spines of the “ crumb of bread sponge,” would have been
slight in comparison.

EUPLECTELLA.

247

DESCRIPTION OF PLATES.

PLATE XI.

Venus’ Flower-basket of the natural size.

PLATE XII.

Fig. 1. Texture of the wall of the tube, magnified.

, 2. The cover of the central tube.

„ 3, 4. The filaments of the basal fringe with apical and lateral hooks,

magnified.

,, 5, 6, 7, 8. Stellate spicula, highly magnified \

From Dr. Bowerbank’s u British Bpongiadce .”

248

JUPITER WITHOUT HIS SATELLITES.

By RICHARD A. PROCTOR, B.A., F.R.A.S.,

Author of u Saturn and its System fyc.

ON August 21, of the present year, the planet Jupiter will
appear in telescopes of moderate power, to be unaccom-
panied for the space of one hour and three quarters by the
satellites usually seen in attendance upon him . This phenom enon
has been so seldom observed that considerable interest is attached
to it. Molyneux on November 12, 1681 (0. S.), Sir W. Herschel
on May 23, 1802, Wallis on April 15, 1826, and Dawes and
Griesbach on September 27, 1843, are, I believe, the only
observers who have hitherto seen Jupiter without his comites. It
cannot be doubted, however, that if the weather be favourable,
the number of observers who have seen the phenomenon, wfill be
very largely increased before midnight August 21. It will not
be wholly as a matter of curiosity that observations will be made
on that night. The record of phenomena presented by Jupiter’s
satellites is a regular part of “ observatory work,” and is very
necessary for the improvement of the theory of their motions, —
an important astronomical subject A special value is attached
to the record of phenomena separated by a small interval of time,
so that the observations made are fairly comparable inter se, free
from the errors arising from variations in clock rates, instru-
mental changes, and the like. Now on the evening of August 21
there will be eight phenomena visible within six hours, — viz. the
disappearances, and reappearances of four satellites. To ob-
servers suitably armed there will, indeed, be no less than thirteen
phenomena visible within the above-named interval ; since of
the entrances and exits of the shadows of three satellites, six
phenomena in all, five will be observable with good telescopes.

Six months ago, I had occasion to treat of Mars, nearly the
lowest in the scale of planetary magnitude, and interesting as
presenting a charming miniature of our own earth. The con-
trast between this orb, and the planet we are now to consider
is marked indeed. Jupiter stands at the other end of the scale
of planetary magnitude. He surpasses our earth more than
1400 times in volume. Saturn alone can be compared with him

Plate XIII .

ww.y.,.

Jupiter and liis System. Aii£. 21^1867. 10^15“-P. M.

JUPITER WITHOUT HIS SATELLITES.

249

in this respect, but even Saturn is but half as large as Jupiter.
In mass, this superb planet is not merely <c facile princeps,” but
exceeds much more than twofold all the other planets taken
together. We may view, indeed, in Jupiter and his system, a
miniature, but instead of being >a miniature of our earth, it is
as a miniature of the whole solar system that he is to be regarded.
The sun himself, does not so greatly exceed Jupiter in volume
as Jupiter does our earth. And the bodies which circle round
Jupiter travel with velocities comparable with those of the
swiftest members of the solar system. While Mercury and Venus
travel 100,000 and 80,000 miles an hour, and our earth travels
68,000 miles an hour round the sun, Jupiter’s inner satellite
travels upwards of 40,000 miles an hour around its primary.
Mars travels 55,000 miles an hour round the sun, the second
satellite travels 32,000 miles an hour round Jupiter. Jupiter
himself sweeps less swiftly round the sun than these satellites do
around him, so that through a portion of their orbits they are
actually retrograding. The third satellite also travels so
swiftly round Jupiter, as to be reduced very nearly to absolute
rest when its velocity acts in a contrary direction to that of
Jupiter. The fourth satellite travels less swiftly than the third,
but yet as swiftly as the planet Saturn in his orbit around the
sun.

Nearly every celestial object has an interest attaching to it,
other than that derived from its physical aspect, — an interest
which may be called historical. In the moon, for instance, we
see an object without which (it is not too much to say) astronomy
would never have approached its present state of exactness and
accuracy. Mars, in like manner, afforded evidence such as no
other planet could supply, when Kepler was engaged in the
series of researches which rendered his name illustrious, and
without which Newton’s views might never have been directed to
gravitation as a universal principle. Venus is connected with
the determination of the fundamental element of all astronomical
measures, — the sun’s distance from the earth. Mercury, Saturn,
Uranus, and Neptune, the sun, fixed stars, comets, asteroids, and
nebulse, all have their historical interest, derived from the evi-
dence which they have afforded on special questions of interest.
Jupiter is second to none in this respect. At a critical period
in the history of astronomy, when the world of science was
divided on the subject of the Copernican Theory of the Universe,
and when all without the world of science were steadfastly opposed
: to the new views, the discovery that Jupiter was the centre of a
miniature-system, circling around him as the theory in dispute
taught that the planets circled around the sun,- — came oppor-
tunely as an illustration, and to those who could grasp the
I significance of the phenomenon, as a proof, of the views of the

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POPULAR SCIENCE REVIEW.

German astronomer. Later came a yet more remarkable and
important discovery, through the observation of Jupiter’s sys-
tem,— the discovery that light does not travel as had been
supposed instantaneously, but with a measurable, however in-
conceivable, velocity. Through this discovery, supplemented by
Bradley’s discovery of the aberration of the fixed stars, came a
proof — which is absolutely beyond cavil or question — of the true
theory of the solar system. Supplementary proofs of Newton’s
views have been derived, also, as might be expected, from the
influence exerted by a planet whose disturbing agency so
largely exceeds that of all the other members of the solar
system.

Let us return to Galileo’s discovery of the satellite-system of
Jupiter, and the influence of that discovery on the views of
astronomers. It was immediately felt, by those who opposed
the new views of Copernicus, that the discovery of Jupiter’s
moons was fatal to their objections. Accordingly they spared
no efforts in casting doubts on the observations of Galileo.
Some asserted that the Tuscan had seen no such sights as he
pretended. Others that he had indeed seen them, but in illu-
sive dreams, that he was the sport of demons specially sent to
punish him for a prying, inquisitive, and truth-doubting spirit.
“We have looked,” they said “for hours through his telescope,
and have seen no such sights as he and his friends have described.”
When at length it was impossible to deny the existence of
Jupiter’s moons, it became the fashion to dispute the real
character of their movements. It was argued that these objects
do not revolve around the planet, but, travel backwards and
forwards behind its disc. Down to the middle of the seven-
teenth century, many refused to believe that the satellites
actually circulate around Jupiter.*

The discovery by Cassini, in 1665, that the satellites can be
traced wdien their orbital motions carry them between the
planet and the earth, placed the true character of these bodies
beyond a doubt. By means of Campani’s object-glasses of 100
and 136 feet focal length, Cassini was able to see the satellites
projected as small bright spots on the disc of the planet. He
found also that their motions when thus situated, are precisely
those due to an orbital motion around the planet, and therefore
very different from those of bodies attached to the planet. This

* Por aught I know the motion of the satellites may he denied to the
present day. In the preface to the last edition (1823) of the Principia ,
edited by the learned Jesuits Le Sueur and Jacquier, there occurs the fol-
lowing remarkable passage : — 11 In adopting the theory of the earth’s motion,
to explain Newton’s propositions, we assume another character than our
own, for we profess obedience to the decrees of the popes against the motion
of the earth.” It is, therefore, not wholly impossible that decrees may have
been promulgated against the circulation of Jupiter’s satellites also.

JUPITER WITHOUT HIS SATELLITES.

251

circumstance, and the fact that the bright spots remain un-
changed in form as they pass over the disc, proved incontestably
that he had not mistaken bright spots, such as are sometimes
seen on the body of the planet itself, for the satellites whose
ingress on the disc he had previously watched. But he was
able to detect another evidence of the true nature of these
bodies, since he discovered that the shadows which they cast
upon the body of the planet, are visible as small dark spots
upon the disc.

Forty years later Maraldi observed that the fourth satellite does
not always present the same appearance as it traverses the disc
of the planet. Sometimes it appeared to him as a bright spot,
at others it appeared darker than the planet. He noticed also
that when the satellite seemed to be projected as a dark spot,,
this spot was smaller than the shadow of the satellite. “ Accord-
ing to the laws of optics,” he says, and others have followed him
in the statement, u it ought to have appeared larger.” Assuming
this view to be correct, and that the observations of Maraldi
were rightly interpreted by him, we are led to a somewhat
singular result. It has been proved, (incontestably, I think)
by Sir W. Herschel’s observations, that all the satellites of
Jupiter follow the law observed in the case of our own moon —
turning constantly the same face towards their primary. He
observed that each satellite varied in brightness in different
parts of its orbit, but that when it arrived at the same position
in its orbit, “ it exhibits always the same degree of brightness.”
It would follow from this, that each satellite in transiting the
disc of Jupiter should exhibit invariably the same appearance —
since when so situated we always see the same half of the
satellite, that half namely which is invisible from Jupiter. This
at least, would always happen, unless a satellite were subject to
transient variations of brilliancy arising from physical change
occurring on its own face. Maraldi’s observation would seem
therefore to point to the occurrence of such changes on the
fourth satellite, and corresponding observations of variations of
brilliancy in the other satellites, by Cassini, Maraldi, and Pound
would lead to the same conclusion as respects these bodies also.
The observation by Bianchini, that in other parts of their orbits
the satellites are subject to considerable variations of brilliancy,
would seem to confirm this result.

How without asserting the impossibility that the above ex-
planation is the true one, I cannot but consider that it is highly
improbable that the satellites of Jupiter are actually subject to
physical changes of the kind implied. The observations of
Sir W. Herschel are decidedly opposed to Bianchini’s view, and
scarcely less directly contradictory of Maraldi’s. It appears to
me far more probable that the apparent loss of brilliancy

252

POPULAR SCIENCE REVIEW.

observed by Maraldi was relative only, and due to the projection
of the satellite on a brighter part of Jupiter’s disc (which we
know to be subject to partial variations of brilliancy) than that
the whole or nearly the whole hemisphere of a satellite should
suffer change in the manner imagined. The fact that the
satellite appears smaller than the shadow, so far from being
contrary to the laws of optics, as many have supposed, is directly
deducible from those laws. The black umbra should indeed be
smaller, but the complete shadow formed of umbra and pen-
umbra together, should be larger than the satellite.

I may notice in passing, that observations having reference
to the relative brilliancy of celestial objects are at all times
difficult, but that those made towards the end of the seventeenth,
and in the earlier part of the eighteenth century, appear
specially unreliable. Whether from the use of unwieldy focal
lengths, or from imperfection in the single object glasses, or
from a want of thorough appreciation of irregularities due to
atmospheric causes, certain it is that there are recorded a mul-
titude of observations of this sort in the interval named, which
have not been confirmed by subsequent observation.

Soon after his discovery of Jupiter’s satellites, Gfalileo per-
ceived the use to which the phenomena they presented might
be applied for the determination of the longitude. He was
sanguine indeed, as to the use of this method for finding the
longitude at sea, not being aware, it would seem, of the mecha-
nical difficulties which render the method unavailable on ship-
board. With the object of constructing tables of the satellites’
motions, he observed them for many years. The Tables he
formed disappeared unaccountably on the death of his pupil
Kimieri, to whom he had entrusted them for publication, and
were accidentally discovered a 'few years ago in a private library
at Eome. Notwithstanding the amount of labour bestowed
upon them, the Tables are far from representing with, accuracy
the motions of the satellites. Gfalileo, indeed, and those who
followed him in attempting the work of tabulating these motions,
altogether underrated the difficulty of the task. A long series
of observations by Hodierna, Borelli, Passim, Maraldi, Bradley,
and a host of other observers, the rigid theoretical scrutiny of
the subject by Newton, Walmsley, Euler, Bailly, Lagrange,
Laplace, and others, and a laborious comparison of the results
of observation and theory, by Lalande, Wargentin, Delambre,
and Woolhouse, have been required to bring the theory of the
system to the exactness and accuracy it has now attained.

The relations actually presented by the motions of the
planets are very singular. They are partly exhibited by the
following Table : —

JUPITER WITHOUT HIS SATELLITES.

253

Sat.

Sidereal Revolution

Same in Seconds

Sidereal Motion
per Second

Distance from
Jupiter’s centre

d. h. m. s.

u

miles

1

1 18 27 33-505

152853-505

8-478706

278,542

2

3 13 13 42 040

306822-040

4-223947

442,904

3

7 3 42 33-360

618153-360

2-096567

706,714

4

16 16 32 11-271

1441931-271

0-898795

1,242,619

It will be observed, at once, that the period of the second
satellite is almost exactly double the period of the first, and the
period of the third almost exactly double that of the second;
and, of course, a corresponding relation holds amongst the
sidereal motions of these bodies. This of itself is remarkable,
but far more singular is the relation which regulates the extent
to which the above relations differ from exactness. It is to
exhibit this that I have added the column of sidereal motions,
because the relation in question is masked when the sidereal
periods only are given. It will be found that the sidereal
motion of the first satellite, together with twice the sidereal
motion* of the third is exactly equal to three times the sidereal
motion of the second satellite. Thus : —

(8"-478706) + 2 (2"-096567) = 12"-671840 = 3 (4"-223947).

To show the effect of this singular relation, suppose the first
and third satellites to start from conjunction, then after four re-
volutions of the first satellite, the second has performed nearly
one revolution, so that they are very nearly in conjunction again,
but have in reality passed their conjunction by a small angle.
At the actual moment of conjunction, the first has described
three complete circumferences and an arc (A, suppose), wThich is
nearly a complete circumference, while the third has described
the arc A only; thus twice the motion of the third satellite
added to the motion of the first gives us three complete circum-
ferences, and three times the arc A ; and therefore by the above
relation the second satellite has moved through one complete
circumference together with the arc A. Hence neglecting com-
plete circumferences the actual change of position of each of the
three satellites is the arc A, very nearly equal to a complete
circumference. They therefore hold the same relative position
at the end as at the beginning of the interval considered. Now
nothing was said as to the position of the second satellite. As
a matter of fact when the first and third satellites are in con-
junction the second is always in opposition to both. Thus the
actual changes of position are those exhibited in fig. 1, in which
it is to be understood that the dimensions of the satellites are
largely exaggerated.

Wargentin, who devoted a life to the examination of the

254

POPULAR SCIENCE REVIEW.

motions of Jupiter’s satellites, but who was no adept in the
higher branches of mathematics, found as the result of observa-
tion that the relation above described was so closely approxi-
mated to, that 1,317,900 years would have to elapse before the
three satellites could be in conjunction. This result affords an
interesting measure of the accuracy of observation up to War-
gentin’s day, since Laplace has shown that the relation is
absolutely exact. Librations may take place on either side of the
mean state (though the most careful modern observations exhibit
no trace of such libration), but there is no possibility of
accumulative change, save by the influence of effective agencies
external to the system. It is somewhat singular that the comet
of 1767 and 1779 passed through the middle of Jupiter’s
system, without producing any observable derangement of the
mean motions of the satellites, — a fact which proves conclusively
that the mass of the comet must be small, its density incon-
ceivably minute.

In Ferguson’s astronomy it is stated that the motion of the
fourth satellite presents no approach to a relation of commen-
surability with those of the others. A simple relation exists,
however, with a closeness of approximation which is quite remark-
able. In fact, throughout the whole solar system there is no
relation of commensurability which brings closely following
conjunction-lines so near to each other as this does.* The
relation is this three times the period of the fourth satellite
is 50d. lh. 36m. 33*8 13s., and seven times the period of the
third is 50d. lh. 57m. 53*520s. ; the difference 21m. 19*707s.
is less than one-1 123rd part of the period of the fourth satellite.
Thus when the third satellite has travelled round seven times
from a given conjunction-line "with the fourth, the fourth has
gone round three times and in addition one-1 123rd part of a
circumference, that is less than 20', and the third overtakes the
fourth before the latter has passed over 15' more (since
15 : 35 :: 3 : 7). This conjunction-line, then is separated from
a preceding one (the fourth preceding) by less than 35'. The
remarkable relation which causes the u Great Inequality ” of
Saturn and Jupiter, brings neighbouring conjunction-lines
nearly 8-J° apart, a distance fourteen times as great as the above.

From the connection between the motions of the first three
satellites, it follows of course that the periods of the two inner
satellites also approximate to commensurability with the period
of the fourth. We have, in fact, fourteen revolutions of the
second, or twenty-eight revolutions of the first, nearly equal to

* Since the above was written, I have found that some tables of elements
of the Saturnian system give such periods to the satellites Dione and Ence-
ladus as to produce a yet closer approach than that of the two satellites of
J upiter whose motions are here discussed.

JUPITER WITHOUT HIS SATELLITES.

255

three revolutions of the fourth: but the approach is not so
close as in the case of the third satellite.

From the relation holding between the motions of the first
three satellites it is impossible that all these bodies should be
eclipsed at once ; but (as will be seen by fig. 1 ) at regular
intervals all three are in the same straight line with the planet’s
centre. If this happen when the sun (and therefore the earth,
which with reference to Jupiter may always be considered to be
close to the sun) is near the same line, these three satellites will
be invisible, one or two being eclipsed, two or one (as the case
maybe) being projected on Jupiter’s disc. Such a phenomenon
is not unfrequently visible.

That the fourth satellite may be hidden at the same time it
must be nearly in a line with the other three. This relation
is not often presented ; and, as already stated, the concurrence of
this relation with the requisite configuration as respects the sun
and earth, is an occurrence very seldom to be observed.

A circumstance that tends to render the simultaneous dis-
appearance of the four satellites more uncommon than it other-
wise would be, is the fact that the fourth satellite is not
necessarily eclipsed or occulted at each conjunction with Jupiter.
It may pass above or below his disc or shadow. In fact this
happens on an average in more than one-third of the revolutions
of this satellite. This is ascribed by Sir J. Hersehel to the greater
inclination of his orbit; but this is not the correct explanation.
In fact the inclination of the fourth satellite is at present less
than that of any of the others, and the mean value of its in-
clination is always less than that of the others. The true reason
why this satellite so often escapes eclipse, is its superior distance
from Jupiter.

It is commonly stated that the third satellite cannot possibly
escape eclipse or occultation as it passes behind its primary, and
must necessarily transit Jupiter’s disc when passing before the
planet. I find, however, that it is just possible for the third
satellite to pass clear of Jupiter’s disc in the latter case. A
conjunction of many favourable circumstances is, however,
required, and the phenomenon must be a very uncommon one
— much more so, indeed, than that which forms the subject of
the present paper. It is necessary that Jupiter should be in op-
position when not far from perihelion, at which time it happens
(and but for this the phenomenon could never take place) that
j the earth is at nearly her greatest distance north of the plane
of Jupiter’s orbit. The satellite’s orbit must have its maximum
! inclination to Jupiter’s orbit, and the satellite must also be at
its greatest distance from the last named plane. The other
satellites must also be so situated that the third is at its maximum
distance from Jupiter ; for it is noteworthy, that although the
VOL. vi. — no. xxiv. u

256

POPULAH SCIENCE KEVIEW.

orbits of the two interior satellites are described as circular, and
that of the third as of small eccentricity, yet these orbits have
an ellipticity due to the mutual attractions of the satellites.
This ellipticity is wholly different from the ellipticity of the
planetary orbits. The former is centric, the latter eccentric, the
sun being in the focus of each planetary eclipse, while Jupiter
is at the centre of the ellipse traversed by the inner satellites.

The following facts combined with the information afforded
by fig. 2, will suffice to enable the telescopist satisfactorily to
observe the phenomenon of August 21. The planet rises at
half-past seven, almost at the same moment that the sun sets.
At 7h 44m Greenwich mean time, the shadow of the third satellite
passes on to the disc, and the satellite itself passes on to the disc
at 8h 14m. The first phenomenon will not be observable, as the
sun will not be low enough beneath the horizon nor Jupiter high
enough above the horizon. Neither will the second phenomenon
nor the entry of the fourth satellite’s shadow on the disc, which
occurs at 8h 17m,be easily seen. The remaining eleven phenomena
will be readily seen, however. At 9h 10m the second satellite will
disappear in the shadow of the planet. At 9h 28m the fourth
satellite will enter on Jupiter’s disc. At 9h 57m the shadow of the
first satellite will make its appearance, followed in seven minutes
by the entry of the satellite itself on Jupiter’s disc. At this
time (10h 4m) Jupiter will be without satellites in telescopes of
moderate power, but large telescopes will exhibit three satellites
on his disc, together with their three shadows. At llh 23m, the
shadow of the third satellite passes off the disc, at llh 49m the
satellite itself. At 12h 13m the second satellite reappears from
behind Jupiter, at 12h 1 6m the shadow of the first satellite passes
off the disc, the satellite itself seven minutes later. Lastly, at
12h 59m the shadow of the fourth satellite, and at 13h 54m the
fourth satellite itself, pass off Jupiter’s disc.

In fig. 2, the paths traversed by the satellites and their
shadows, are indicated. The figure represents the appearance
presented in an inverting telescope. It is only necessary to
invert the figure to see the actual configuration. It will of course
be understood that the apparent slope of the paths will vary
with the hour of observation. I have made the planet’s equator
horizontal, instead of estimating the slope for any assigned
hour; because the planet’s oblateness being very observable,
affords a natural feature of reference.

It will be observed that the shadows of the four satellites are
very different in appearance. I have drawn them, not as they have
been seen in the telescope, but as it is certain that they would
appear in telescopes of adequate power. The figure and extent
of the penumbrse have been determined from the simplest optical
principles applied to the known distances and magnitudes of the

JUPITER WITHOUT HIS SATELITES.

257

satellites. The figures of the shadows will suffice to afford an
easy explanation of Maraldi’s observation, that the shadow of the
fourth satellite appears larger than the satellite.

At 10h 15m p.m. August 21 the positions of the satellites and
shadows are those shown in fig. 2, the second satellite being, of
course, behind the disc. A little examination of the figure
will show that a few minutes after half-past eleven the three
interior satellites are in the same line with the planet’s centre.

U 2

258

FITZ-ROY WEATHER FORECASTS.
By G. F. CHAMBERS, F.R.A.S.

IN the present article I propose to give a general account of
that system of weather forecasting commonly associated
with the name of the late Admiral Fitz-Roy, discussing it his-
torically and practically. The importance of the subject can
hardly be over estimated: all classes of the community are
more or less benefited by fair weather and prejudiced by foul
weather, and some prior knowledge, however general, of what is
to be, would rarely fail to promote our convenience in the busi-
ness and pleasures of daity life.

Few sciences have been studied in a more desultory way than
Meteorology, and though this remark is less true than it was a
few years ago, the reproach is by no means removed. On this
point Admiral Fitz-Roy felt very warmly and he seems to have
been almost the first man who infused into the subject an
element of practical application. In 1853 there was held at
Brussels an international Maritime Congress at which Meteoro-
logy as bearing on Navigation was discussed, and in 1859 the
British Association recommended to the Board of Trade the
adoption of storm-signals to be circulated by aid of the electric
telegraph. This recital brings us at once to the question we
have in hand. Consequent on the recommendation above
alluded to, Admiral Fitz-Roy was directed by the Board to
prepare a scheme for conveying to certain seaports, connected
with London by telegraph, intelligence of approaching storms.
Nothing in the way of prediction 'was contemplated, only
announcements of storms at some places, which storms might
be expected after short intervals of time to manifest themselves
at others. The conductor of the new movement was not satis-
fied with this moderate advance; he. thought that more could
be done and ought to be done and that he would endeavour to
do it ; in short that predictions or approximations to predictions
two or three days in advance were fairly feasible. “ From the
very first the project was more or less opposed by many, and the
old sea-wolves of the North for some time looked upon it with
contempt. One day however Admiral Fitz-Roy ordered up his
‘ south cone ’ meaning that a storm was approaching from the

Fitz-Eoy’s Day Signals.

Fitz-Eoy’s Night Signals.

FITZ-ROY WEATHER FORECASTS.

261

south. The good folks of Newcastle laughed at the signal. Why
shouldn’t they ? The sky was clear and c all serene.’ They
could see nothing to warrant the probability of a coming
tempest. The fishermen put out to sea as usual. On the fol-
lowing morning, however, the coast was covered with wrecks,
and many a family had to bewail the imprudence of the
unfortunate men who had disregarded the signal. After that,
people began to think that there was something in the system,
and numerous subsequent fulfilments more and more confirmed
the popular belief in the utility of the predictions.” *

The first cautionary or storm-warning signal was issued early
in 1861, being the one alluded to in the previous extract. In
August of the same year the 'publication of forecasts was com-
menced, and after six months had elapsed for gaining experience
by varied tentative arrangements, the system was launched in
its final form which, so far as Admiral Fitz-Eoy was concerned,
remained in operation till his lamented death in 1865. The
ultimate procedure was the reception by telegraph of about 18
weather reports every morning (except Sundays) from British
coast-stations, besides a few from the continent. These reports
gave (in cypher for the sake of brevity) the leading meteoro-
logical elements of the place of observation ; such as height of
the barometer, temperature, wind, rainfall in previous twenty-
four hours, state of the atmosphere, sea, &c. The information
thus conveyed to the London office was immediately reduced in
the usual way by the application of the necessary corrections
and written out in prepared forms. The first copy, with the
original telegrams, was passed to the chief of the department or
to the deputy appointed to act in his name, to be studied and
discussed for that day’s forecasts.

At about 11 a.m. expanded copies of the telegrams, together
with the forecasts arrived at by the officer in charge, were sent
to certain newspapers to be published in their next impressions.
Copies of so much of the forecasts as related to the English
Channel were also telegraphed to Paris (by special request) for
the Ministry of Marine. The whole of this work was got
through by about 12 o’clock. In the afternoon, from a few of
the stations further telegrams were received and when , and so
far as necessary, these were used to revise the forecasts of the
morning, for the morning papers of the following day. In
addition to this daily service occasional storm-warnings were
sent to our own coasts, and to Paris and sometimes to Ham-
burg, Hanover and Oldenburg, by the request and at the expense
of the public authorities in those states.

We shall presently discuss the basis on which these forecasts

Steinmetz.

262

POPULAR SCIENCE REVIEW.

were framed and enquire into the value they were found to
possess'; but, before doing so, let us describe the mechanical
arrangements adopted for signalling them, and illustrate by
actual examples from official sources the details of the modus
operandi , of which an outline only is presented above.

The necessary apparatus consists of a mast, .of any convenient
height (thirty or forty feet) two yards from four to six feet in
length with the necessary ship’s tackle, a cone, a drum and four
signal lanterns. The cone and drum are wooden frames of
those shapes covered with canvas and each about three feet
high ; any sort of lanterns may be used, but they must be of
good size and show the same colour ; what that colour be is not
of great importance but red is to be preferred as the colour
which is most conspicuous.

When hoisted, the cone appears as a dark triangle, and the
drum as a dark square, and the import of the various signals
is as follows : —

The cone with the point upwards, shows that a gale is
'probable ; at first from the northward . This is termed for
brevity “North Cone,” fig. 1.

The cone with the point downwards shows that a gale is pro-
bable ; at first from the southiuard . “ South Cone,” fig. 2.

The drum alone, shows that stormy winds may be expected
from more than one quarter, fig 3.

The cone and drum together give warning of dangerous winds,
the probable first direction being indicated by the position of
the cone and its apex : cone over drum and point of cone upper-
most for northerly wind (fig. 4) : cone below drum and point
downwards for southerly wind (fig. 5).

When these signals were, in consequence of telegrams from
London, made at the several stations warned, they were kept up
till the dusk of that day only, and in the official instructions
issued it was stated “ These cautionary signals advert to winds
during some part of the next night and two or three days ;
therefore due vigilance should prevail (until the weather is
again settled) without deferring departures or any operations
unnecessarily .”

In night signalling, only one of the two signals was used ;
drum or cone, but not both. This was for the sake of simplicity
and saving of trouble.

Let us now revert to the procedure at the Central Office in
London. When the system was first instituted the British Isles
were divided into 6 districts, viz.: —

1. “Scotland.”

2. “ Ireland,” around the coast.

3. “ West Central ” (from the Severn to the Solway).

FITZ-ROY WEATHER FORECASTS.

263

4. “ South-West England ” (from the Severn to Southampton
Water).

5. South East England ” (from the Isle of Wight to the
Thames).

6. “ East Coast ” (from the Thames to the Tweed),
the coast being in each case the points cVappui.

These districts were subsequently consolidated, into four
viz. : —

1. “ Northern” (Scotland).

2. “ Western ” (Ireland, Wales).

3. “ Southern ” (English Channel and Bay of Biscay).

4. “Eastern” (the East Coast of England and the North
Sea.)

The telegraph being the agency for the transmission of weather
news, and telegraphic messages, especially those involving figures,
being costly and peculiarly liable to error, it became a matter
of leading importance both to simplify and abbreviate the
messages in every way possible. As a first step it was decided
to discard words as far as possible, except for special purposes,
and to dispense with headings, using only figures disposed in
groups, the position of the figures in the several groups being,
by pre-arrangement, understood to refer to certain particular
meteorological elements and none others.

Thus : —

Aberdeen to London; 1862, July 25, 8 a.m.

06041 . 93453 94663 21072 60420 05628

This message expanded, and written out in the style familiar
to every daily newspaper reader, becomes : —

1862.

July 25, 8 A.M.

1

B

E

D

W

F

x

c

! i

H

R

s

j Aberdeen . .

29.39

60

6

sw

5

8

6

r

6

0.46

8

Appended to every Table thus circulated was the following
“ Explanation ” : —

B. — Barometer corrected and reduced to 32° at mean sea-
level; each 10 feet of vertical rise causing about th of an inch
diminution , and each 10 degrees above 32° causing nearly th
increase. E. — Exposed thermometer in shade. D. — Difference
of moistened bulb (for evaporation and dew point). W. — Wind
direction (true — 2 points left of magnetic). F. — Force. I. —
Initials : b , blue sky; c, clouds (detached) ; /, fog; A, hail; l ,
lightning ; m, misty (hazy) ; o, overcast (dull) ; r, rain ; s, snow ;
t , thunder; H. — Hours of B = Bainfall, or snow or hail (melted),
since last report. S. — Sea-disturbance (1 to 9), Z calm.

264

POPULAR SCIENCE REVIEW.

Eventually so much of this “ Explanation ” as could be so
placed, was prefixed to the columns in the daily tables : hence
their present form differs somewhat from the above, and they
have become more convenient for perusal.

The plan upon which the meteorological information is
reported to head-quarters from the several stations may be thus
epitomised. Each telegram consists of five or six groups of figures
(each group containing five figures) and occasionally a few words.
No alterations or reductions are made by the observer who
transmits them as they are read off, except in a few special
cases. The reductions are performed in London with the aid of
data, furnished as occasion may require, by the several observers.
The first group is Eainfall (R.) omitting decimal points. With
each morning report, when rain enough has fallen to be
measurable, its duration in hours from 1 to 24 (or to 48 after
a Sunday or holiday) occupies the first two places of a 5-figure
group, a cypher being prefixed before 1 to 9: quantity of rain
(snow &c. melted) is shown by the last three figures of the five as
inches and hundredths. Thus if rain has prevailed for four hours
since the previous report and half an inch is the gauge, the
group will be 04050; if for fifteen hours with one inch and
three quarters, the group will be 15175.

The second group of figures shows the highest or lowest
extreme (the most remarkable) of the mercury in the barometer
(B) and in the exposed thermometer (E) since the previous
report by telegraph. B occupies the three first places of the
group for the last integer and two first decimals ; and 2 the two
final figures for whole degrees of the exposed dry thermometer.
Thus if the extreme reading of the barometer has been 30T29,
and that of the thermometer 54*3 the group for the telegram
will be 01354, the reading of the barometer being in all cases
taken to the nearest hundredth and of the thermometer to the
nearest whole degree.

The third group of five figures is devoted to the height of the
barometer and of the attached thermometer at the regular
observing hour be it 8 A.M. for a morning telegram, or 2
p.M. for an afternoon one, the method of enunciating which
will be understood from the last paragraph.

The fourth group expresses the extreme, not simply the general
character of the wind and weather (D F I) since the last report.
The first two figures are allotted to the direction of the wind (D)
the third and fourth to the force (F) and the last figure to the
character of the weather. The direction of the wind is repre-
sented by figures 1 to 32, one for each point of the compass
from N. round by E. S. and W. to N. again. North being 32, East
8, South 16, and West 24, and so proportionally for the interme-
diate points. A cypher preceding the points numbered below 10

FITZ-ROY WEATHER FORECASTS.

265

( = N. by E. to E. by S.) to keep the figures in their places.
The scale for force of wind (F) is 1 to 12. The character of
the weather is represented by a scale of figures from 1 to 9 as
follows : —

Thus, if we suppose the extreme direction of the wind
since the last report to be S. the extreme force to be 8, and the
general character of the weather gloomy and overcast, the tele-
graphic group will be 16086.

In the fifth group the first two figures show the reading of the
exposed thermometer, (E) the third figure is difference above
the damp one (wet bulb ; D) and the two last figures the true
direction of the wind. Thus, if the dry bulb be 58° and the
wet one 52° . (difference = 5°) and the wind W., the group of
figures for telegraphing will be 58524.

In the sixth and last group the first two figures belong to the
estimated fforce of the wind (F) from 1 to 12, 1 standing for a
faint breeze, and 12 for a hurricane, a cypher preceding one-figure
quantities ; the third figure is devoted to the amount of cloud
(C) from 1 to 9, 1 standing for a few clouds, and 9 for sky wholly
overcast. The fourth figure gives the character of the weather
according to the notation above, and the fifth figure the condition
of the sea (S), also from 1 to 9. Thus, if the wind is blowing
moderately, and the sky be very cloudy, the weather fine and
the sea rough, the telegraph word will be 04217.

*This system of reporting by telegraph the state of the weather
at various widely separated stations, first set afoot by Admiral
Fitz-Roy, has been maintained up to the present time, but its
auxiliary, the digesting of this telegraphic news, and evolving
from it some general conclusions as to the wTeather probably
imminent, was summarily stopped by superior authority on the
Admiral’s death : a triumph which I trust is only temporary
was given to the party, who looked upon him as a meteorological
poacher, and who unceasingly sought to run him down ; but all
practical men who had watched with pleasure the progressively
improving value of the forecasts, and especially those whose
interests were most connected with the mercantile marine,
learnt with great regret the decision of the (late) government,
and increasing efforts have been made to procure its re-
versal, but hitherto (May 1867) without success. The govern-
ment it must be admitted did not give the Forecast system an
unqualified quietus: they appointed a committee of scientific
men to enquire into the whole administration of the meteoro-

1. Fine, clear.

2. Cloudy.

3. Fog.

4. Lighting.

5. Misty, hazy, obscure.

6. Gloomy, dart, overcast.

7. Rain.

8. Snow.

9. Thunder.

266

POrULAR SCIENCE REVIEW.

logical department of the Board of Trade and to report thereon
before the vacant directorship was filled up, and this committee
was specially enjoined to consider the Forecasts as to their basis,
and value. Their report was adverse, on the ground that sufficient
data on which to found reliable predictions had not been ac-
cumulated ; but this their expression of opinion was strangely at
variance with the body of evidence to the contrary laid before
them, and actually printed by them in their Blue Book.

They addressed through one of the permanent officials of the
Board of Trade to persons occupyiug official positions at various
seaports, collectors of customs, secretaries to marine boards, and
the like, the following very peculiarly worded question. “ What
is the opinion of seafaring men concerning the value of the late
Admiral Fitz-Boy’s signals? Can you help us by telling me
what is thought of them by those most competent to judge.”
[in your locality] ?

The answers were, with one exception, highly favourable to
the Fitz-Boy system. The following are some samples of them.
<c The utility of the signals is generally acknowledged, and for
some time back the subject has obtained more attention among
seafaring men. The signals for a considerable time have been
very accurate.” Thus wrote a competent person at Aberdeen.
Dundee said 66 The correctness of the storm signals at this port
is a matter of common remark ; they are very generally appre-
ciated.” The Shipowners’ Society of South Shields state that
“ the exhibition of the storm signals is of much practical value
by giving timely warning of approaching storms.” The testi-
mony from Deal is very emphatic : — “ There is but one opinion
concerning the value of the signals. They have been the means
of saving life and property to an immense amount.” The other
favourable answers were all couched in much the same terms.
And in regard to the one hostile opinion it is worth mentioning
that the writer (who hails from Plymouth) seems carefully to
guard himself. He takes shelter under the very vague phrase,
“ Those most likely to be infoimied on the subject do not con-
sider that the signals are in any degree of value to seafaring
persons.” It must I think be conceded that this expression of
opinion would have been more satisfactory had some degree of
particularity characterised it, had there been some statistics,
some actual record of the facts (if any) on which it was grounded.
Considering the unanimity prevailing amongst the representa-
tives of the mercantile marine on the subject and the untiring
efforts they have made to get the system again set on its legs,
one is not a little puzzled to understand by what process of
reasoning the committee arrived at what I venture to call their
astonishing conclusion. “ There is as yet no scientific basis for
these daily forecasts, they are not shown to be correct in point of

FITZ-ROY WEATHER FORECASTS.

267

fact, and there is no evidence of their utility [! ! !] and we see
no good reason why a government department should continue to
undertake the responsibility of issuing them,” or, as they else-
where in their report express it : — “ There is no evidence to show
that the daily forecasts have been correct in point of fact, or that
we are enabled — as Admiral Fitz-Roy declared — to know what
weather will prevail during the next two or three days, and as
a corollary, when a storm will occur ; on the contrary, the
evidence points strongly the other way.”

I do not in the least desire to impugn the bona fides of the
Committee of Investigation nor to deny that their report contains
much that is interesting in itself and of suggestive practical
value, still their bias against Admiral Fitz-Roy is manifest. The
strongest part of their case is where they allege that one of the
leading defects of the Forecast system which they found in
operation at the Board of Trade was that everything was con-
ducted too much by rule-of-thumb, or as they put it ; tf Many
conditions and probabilities of weather are capable of being
stated in the form of laws and some of them are laws which
would be accepted by meteorologists generally ; the probabilities
are in many cases considerable, and especially in the important
cases of sudden and violent changes of weather,” but they cc do
not find that these conditions and probabilities have been reduced
into any definite or intelligible form of expression, nor are they,
as they now exist in the office, capable of being communicated
in the shape of instructions. Were the gentlemen now in the
department to leave it , no rules would be found in the office for
continuing the duties of their present basis.” We are bound
to receive this as an accurate statement, but it is not easy to
reconcile these words of the committee with the fact that they
have themselves presented us with a digest of twenty-four
practical maxims which embody, as they imply, the leading
principles upon which Fitz-Roy and his able colleague Mr.
Babington actually were in the habit of preparing the forecasts
of the weather. After all, then, it seems that some rules, or at
least some materials for framing rules, have been found in the
office and by the committee themselves, despite of their con-
fident assertion that nothing existed “ capable of being communi-
cated in the shape of instructions,” for I assume that they would
hardly attempt to justify such a statement as this by saying that
the digest of maxims which they publish had no existence until
they gave it one. This cannot be their meaning, I should think.

Proceed we now to consider briefly the basis of the Forecasts.
I have admitted that perhaps there was a certain amount of rule-
of-thumb in what Fitz-Roy did, but inasmuch as greaft results
were clearly achieved by him, it would be impossible not to be
able to derive some benefits from the notes and memoranda he

268

POPULAR SCIENCE REVIEW.

left behind him, allowing as I freely do, that his literary style
was wordy and diffuse to a most uncomfortable degree.

The following is a summary of the maxims employed in the
Meteorological Office for forecasting the weather.

1. In the latitudes of the British Isles , and of North Western
Europe generally there are two and only two essentially different
atmospheric currents of importance, one S.W. running from
the equator towards the pole, and the other N.E. running from
the pole towards the equator.

2. The weather in this country depends almost wholly on the
conflict, combination, alternate preponderance, or alternate suc-
cession of portions of these opposite currents.

3. The characteristics of the S.W. current lie not only in its
general direction but also in its quality, for it is light, warm
and moist. In other words its presence is shown by a low
barometer, by a high thermometer, and by a small difference
between the wet and dry bulb thermometers.

4. In a similar way, the characteristics of the N.E. current lie
not only in its general direction, but also in its quality, for it is
heavy, cold and dry. In other words its presence is shown by a
high barometer, by a low thermometer, and by a large difference
between the wet and dry bulb thermometers.

5. Not only is the actual presence of either current shown by
its corresponding instrumental test, but an approaching change
from one current to another is foretold by the instruments
beginning to change their indications. Hence as changes of
weather must necessarily commence at some places earlier than
at others, there is great advantage in receiving by telegraph,
information of the state of the weather and of the instruments at
many stations.

6. Owing to frequent conflicts of portions of the S.W. and
N.E. currents followed by a temporary variation in their courses,
the direction of the wind is by no means a certain test of the
nature of the current of which it forms a part. A volume of
air may even become wholly detached from its parent current,
and be enclosed in that of its antagonist, and be drifted along
with it.

7. When the S.W. and N.E. currents intermingle, water is
precipitated in the form of cloud, rain or snow.

8. Most of our violent storms travel bodily in a N.E. direction.

9. The whole body of the atmosphere in our country travels
in an E. direction at the rate of from two to eight miles an hour.

10. When S.W. and N.E. currents alternately prevail, the
wind blowing over any station has a strong tendency to “veer 5 ' and
not to back. That is to say, the general order of the changes is
N., E., S., W., N., and not N., W., E., S., N.

11. The result of all rapid changes in the weather or in any

FITZ-ROY WEATHER FORECASTS.

269

of the instrumental indicators, is brief in duration, while that of
a gradual change is more lasting.

12. Eapid changes of all kinds commonly presage violent
atmospheric commotion.

13. The wind usually blows from a region where the barometer
is high to one where it is low.

14. The force of the wind is usually proportionate to the
differences of barometric pressure at adjacent places. In other
words the greater the barometric tension the stronger the wind.

15. Strong winds are far more steady in direction than light
or moderate winds.

16. Great storms are usually shown by a fall in the barometer
exceeding 1 inch in 24 hours, or by a fall of nearly of an
inch in one hour.

17. The barometer frequently continues high during a JST.E.
storm, but there is a fall of the thermometer.

18. Gradual changes of weather are shown by a gradual rise
or fall of the barometer ; for instance by a rate of of an
inch in one hour.

19. Great differences of temperature at the same or adjacent
places are followed by changes of weather.

20. It is concluded from the foregoing remarks that a know-
ledge of the differences in the barometer and thermometer at
different times in the same place are no less important than a
knowledge of those simultaneously observed at different places.

21. Sea disturbance often precedes gales.

22. Great storms are frequently preceded by excessive
meteorological disturbance or by heavy falls of rain or snow, by
much lightning, by unusual cold, or by excessive heat.

23. Calms may be due to either of three different states of
weather : — (u) The appulse of winds coming together from
opposite quarters. (6) The divergence of winds going towards
opposite quarters, (c) The centre of cyclonic storms. The
barometer rises in (a) sinks in (6) and is extremely low in (c).

24. Beyond a doubt electricity plays an important part in
the state of the weather, but at present we possess no means of
stating any defined conclusions.

The forecast for each of the districts into which the United
Kingdom was divided, was obtained by summarising the actual
weather prevailing in the several districts and by applying to
this summary the foregoing maxim. The separate forecasts
were then collated and revised, regard being had to (1) the
mutual actions of the estimated weather in each of the other
districts. (2) To scattered information in respect to such
distant areas of high and low barometer, as the limited number
of continental stations afford; and (3) to geographical conditions
of mountain, plain, or sea by which the free movements of the

270

POPULAR SCIENCE REVIEW.

air may be affected. “ It is the custom of the department to
perform the whole of the foregoing operations and to determine
the forecast after a simple inspection of the list of weather
returns. No notes or calculations upon paper are made. The
operation lasts about half-an-hour and is conducted mentally.5’
The committee admit that they know nothing as to how Admiral
Fitz-Eoy dealt with (1) but they next give in their report some
elaborate calculations founded on the doctrine of probabilities by
which (as they no doubt suppose, fairly) they show the value of
the forecasts to be practically nil. I conceive it to be quite
unnecessary either to reproduce or to comment on this special
pleading in the face of the testimony set forth in an earlier part of
this article. If further proof were necessary that the committee
in doing their work were embarrassed between their prejudices
on the one hand, and the hard logic of facts on the other, it is
I think to be found in the circumstance, that, whilst they do
recommend the discontinuance of daily forecasts, they do not
recommend the abandonment of the occasional storm warnings,
but seek to draw a distinction between these (which it is sub-
mitted), cannot be supported. However as a matter of - fact,
everything in the nature of prediction has been abandoned, and
it now remains to be seen what will be the result of the pressure
which it is sought to bring to bear on the Grovernment and the
new director of the Meteorological department, Mr. E. Scott.
Into a general discussion as to the means we possess by notorious
signs, for anticipating the weather that is to be, the space at my
disposal does not permit me to enter; the subject, however, as I
should wish to treat it, is essentially distinct from the purpose of
this article.

ON LIFE INSUEANCE AND VITAL STATISTICS.

By W. HARDWICKE, M.D.,
Deputy- Coroner for Central Middlesex , 8fc.

WE propose in the following pages to discuss, as briefly as
possible, and without technical and mathematical re-
ferences, the principles of Life Insurance, and to $how, in a
social point of view, the important and intimate relations of
the science of Vital statistics with our commercial prosperity.

With the mass of mankind, individual efforts suffice to pro-
vide for little more than daily^necessities, and it unfortunately
happens, that the unexpected death of a parent, or some sudden
exigency, leaves a wife and family unprovided for, or entails
upon them the necessity of maintaining themselves under the
pressure of adversity, or of relying upon others for their sup-
port.

The most observable feature in English character is a love of
independence, and this feeling the principles of life assur-
ance serve above all others to foster, and annihilate that sense
of insecurity in individual effort, of which most persons are
conscious. Life assurance is indeed a contract with certain
parties who invest money by which the uncertainties of life are
compensated, and by which the representatives of those who do
not live the average time share in the good fortune of those
who exceed it.

The words Insurance and Assurance are vaguely defined, but
may with propriety be used synonymously. The word insurance
is mostly used when speaking of indemnity for loss of property
by fire or shipwreck ; while assurance generally refers to money
payment upon death, or upon other contingencies depending
upon the duration of human life.

To be assured or made sure, and to be insured is much the
same thing. There is, however, a distinction, which has, per-
haps, a moral as well as a legal significance. Insurance against
fire more nearly resembles a bargain or commercial speculation
for realising a sum of money upon a chance event. Life
VOL. vi. — NO. xxiv. x

272

POPULAR SCIENCE REVIEW.

assurance business, on the other hand, depends upon a certainty
—death — which, with the duration of life, may be brought
under mathematical calculations. This view has not always
been recognised; for, at one time life assurance and annuity
speculations led to the enactment of laws which made penal the
staking of money, by annuities or insurance, on the life of the
pope, or of a king or bishop. It was believed that such trans-
actions were attended with danger, inasmuch as those persons
might be privately despatched for the pecuniary benefit that
would accrue to some of those interested in their death.

Life assurance, based upon system, is, however, of modern
origin. Till the beginning of this century, there were not more
than half-a-dozen offices in existence. The two oldest are the
Amicable (1706), and the Equitable (1762). In 1813, there
were only fifteen offices ; in 1825, thirty-two ; whilst, at the pre-
sent time, there are at least two hundred life assurance offices
well-established in this country, employing no fewer than 2,000
directors and managers, with a corresponding number of clerks ;
moreover, agents in all our large towns are working outandrapidly
extending the principles and practice of life insurance amongst
the community. The wealth of some of these offices is enor-
mous. In 1864, when the directors of seven insurance offices
signed a memorial to the Chancellor of the Exchequer not to
trespass upon the domain of legitimate private enterprises by
introducing a government scheme, it was stated that the funds
of these companies represented a capital of 100,000,000^; the
amount assured 300,000,000^., and that new assurances were
being effected at the rate of 30,000,000^. per annum. At the
same time, it is estimated that not more than a tenth of the
adult male population insure.*

Friendly societies are essentially the provident life assurance as-
sociations of the industrial ranks. They reckon above 3,000,000
members, contributing an annual revenue of 5,000,000^., and
possessing an accumulated capital of 20,000,000^. ; and when the
habit of life assurance becomes more general among the arti-
zans’ class, and when, as must eventually happen, the system

* Life assurance was not altogether unknown to the Romans. We have
a singular record of the earliest Friendly Society in a monument discovered
in Italy, where the laws of the association were inscribed on marble. It
was a kind of burial club, meeting monthly. New members had to present
wine, besides 15s., at entrance ; 2d. a month was the subscription, and 21. 5s.
was allowed for funeral expenses ; and the rules for preserving order and good-
fellowship, and others relating to business, very much resembled those of
modem friendly societies. In the middle ages, again, freemasonry, guilds,
and corporations, besides promoting religion and trade, carried out the
principles of mutual aid and protection, by granting pecuniary benefits to
widows and orphans; and in modern times friendly societies are but a
further development of life and health assurance principles.

ON LIFE INSURANCE AND VITAL STATISTICS.

273

will be recognised as the only legitimate means of repressing
pauperism and avoiding the social misery which follows it, there
will be an unlimited field for provident investments on life
assurance principles.

The success many of these institutions have justly acquired
in England, together with the confidence existing in commercial
circles for this kind of security, makes this country stand pre-
eminent, whilst it enables offices to establish agencies for carry-
ing on their operations in all parts of the world. Life assurance
is less successful, but gradually increasing, on the Continent.
The French government endeavoured to encourage life assurance,
and Napoleon ordered the Mayor and Cure of every commune
to establish a societe de prevoyance et de secours mutuel. In
1850 the National Assembly passed a law for establishing “ une
caisse de retraite , ou rentes viageres pour la vieillesse ,” a sort
of superannuation or annuity fund for aged persons. The
management of most of these associations is virtually in the
hands of the government, inasmuch as the Emperor has power
to nominate the president, while the number of honorary and
recipient members cannot exceed 500 without the authority of
the prefects or minister of the interior.

In Germany, America, and, very recently, in England, the
governments have attempted to legislate in favour of Life As-
surance. It would be well if employes in government and
public offices were compelled, as in Germany, to invest a por-
tion of their salaries in life assurance benefits for their widows
and families. Perhaps, likewise, a more compulsory system, for
preventing wide-spreading pauperism, may be deemed desirable
in this country, when the plans, now failing, have been tried a
little longer.

The science of vital statistics, upon which life assurance is
founded, is one of great practical interest. It was, at one time,
based upon data that were tentative ; but it may now justly be
considered as elevated to the rank of a science ; for, by natural
contingencies that admit of calculation, we may predict the
average duration of life, under given conditions, almost with as
much certainty as an astronomer can predict an eclipse of the
sun. The mortality tables, founded on these calculations, are
to the science of vital statistics what the balances, thermo-
meters, and barometers are to investigations in physics. They
serve to measure the life-force of individuals and nations, the
years of life being units in the scale.

However uncertain any individual life may be, the uniformity
of average is such that, where large numbers are concerned, a
small fractional difference only is observed, but sufficient pre-
cision is attained for all practical purposes. Various tables have
been calculated, to show the average duration of human life at

274

POPULAR SCIENCE REVIEW.

all ages: one by Dr. Price, in 1782, called the Northampton
table, framed, from the ages at death of persons buried at North-
ampton, during forty-six years (1735-80). The Carlisle — a less
accurate table — was compiled by Dr. Milne, from the mortality
deduced from persons at Carlisle. More recently, a table was
constructed from the ages at death of persons actually assured
in several offices ; this is called the “ Experience table.” All of
these, and one by Mr. Finlaison, calculated from 22,000 govern-
ment annuitants, represent the expectation of life in persons of
the higher and middle grades of society. Lastly, an English
Life table was calculated, under the auspices of Dr. Farr, soon
after the census of 1841, from a population of 16,000,000 per-
sons, and the ages of death in 2 ^ millions of persons. This may
fairly be considered to represent, for all practical purposes, the
mortality in the higher classes, professional persons, tradesmen,
artizans, clerks, and servants. A further set of observations are
said to be forthcoming; but they will not materially modify the
character of the English Life table.

The most valuable and recent contribution to statistical
science, however, is the supplementary volume of the Regis-
trar Greneral on the mortality of England during the last ten
years, for which wre are also indebted to Dr. W. Farr. This
forms a most worthy complement to his former labours, in
elaborating a perfect English life-table. These returns show
the annual rate of mortality per 1,000, in a very extensive
series of tables, from the age of five to eighty-five years and
upwards, as well as the causes of death. These records enable
us to observe the diversity and duration of life, in towns and
country, in densely and scattered populations, amongst rich
and poor, in agricultural, manufacturing, marine, and inland
districts ; gives us the opportunity of comparing and classi-
fying these with each other, and of observing the differences
effected by soil, climate, and occupation.

It is evident, from the perusal of this work, that there are
certain districts and occupations where the mortality far exceeds
the healthy standard, at ages when the majority of proposals are
made for life assurance, viz. from twenty-five to forty-five.
In some localities lung diseases, for instance, range from two
and a half to eight times the normal average of healthy dis-
tricts.

The following tables serve to illustrate : —

ON LIFE INSURANCE AND VITAL STATISTICS.

275

1. — Differences in the ?nean Duration of Life.

Ages.

English.

In

Towns.

Country.

Irish.

North-

ampton

Table.

French.

! Males.

Females.

Difference.

Males. | Females.

Difference.

20

Y. M.

36 6

Y. M.

37 6

Y. M.
0 11

Y. M.

41 2

Y. M.

40 4

Y. M.

34 11

Y. M.

33 5

Y. M.

38 5

Y. M.

44 0

Y. M.

5 7

30

33 2

34 3

1 0

34 10

34 2

29 8

28 3

33 2

37 7

4 5

40

26 6

27 9

1 3

27 6

27 4

23 4

23 1

27 0

31 1

4 1

Ages.

In Whitechapel.

In St. George’s,
Hanover Square.

Difference.

20

33 years 6 months

39 years 6 months

6 years.

50

15 „ 11 „

18 „ 8 ,,

3 •„

2. — Expectation of Life.

Ages.

North-

ampton

Table.

Carlisle

Table.

Equitable

Society.

Govern-
ment An-
nuitants.

Experience
of 17
Offices.

Dr. Farr’s
English
Life Table.

French

Life

Tables.

25

Y. M.

30 10

Y. M.

37 10

05k|

00-

H->.

Y. M.

38 4

Y. M.

37 11

Y. M.

36 8

Y. M.

37 2

30

28

3

34

4

34

4

35

5

34

5

33 2

34

1

40

23

1

27

7

27

5

29

1

27

3

26 6

27

6

The mean expectation of life term in —

London is 37 years, where there is one death annually in 41 persons--
Liverpool „ 26 „ „ „ „ „ 30 „

Surrey „ 45 „ „ „ » „ 52 „

This average duration and expectation of life are the elements
on which payments are calculated, to carry out a contract for
assurance. An office may insure for the risk of death during
one year, or for the whole future years of a person's life, as
shown by the annexed English Life table. At twenty-five, the
full expectation of life is thirty-seven years; and 38£. Is. in-
vested at three per cent, for that period will, yield 100£. ; but a
man may agree to give only 16s. 10<A for a single year’s risk.
This is termed “ natural ” premium, while it would require
1 L 14s. 11 annually for the remaining years of his life if an
“ invariable ” or 6( uniform ” premium were paid.

276

POPULAR SCIENCE REVIEW.

English Life Table (Males'), Interest at 3 per Cent.

Age.

Males living
in 1000 born.

No. dying in
following year.

Years Expect-
• ation of Life.

Premium
for one
Year’s risk.

Annual
Premium
for the
whole Life.

Premium
in one
Sum.

Value of
an

Annuity
of 11.

Life

Annuity
which 1007.
win

purchase.

25

321

3

37

£ s. d.

0 17 2

£ s. d.

38 1 0

£

1

s. d.

15 9

£ 5. d.

21 5 5

£ s. d.

4 14 0

30

307

3

33

0 18 11

41 3

8

2

0 9

20 3 11

4 19 0

35

291

3

30

113

44 13

6

2

7 0

18 19 11

5^3

40

275

3

26

14 6

48 10

9

2

14 11

17 13 5

5 13 2

In some of the old tables higher rates were charged. Such is
the practice generally adopted. The amount in this table is
without the addition or loading of premiums, for the purposes
of management, profits, bonuses, and other contingencies.

Some offices have a table of rates increasing every five years ;
others may prefer decreasing rates of premium, graduated in
various manners. It matters not much, however, at what age
a person commences assurance; the more advanced in life of
course pay higher premiums, on the chance of dying sooner,
whilst the younger lives have smaller premiums, but a greater
number of them. But the advantages of insuring young are
manifold; bonuses steadily increasing may often double the
sum insured. In the Government Life Assurance and Annuity
tables the premiums are very judiciously calculated to stop at
the age of sixty, inasmuch as, after that age, ability to earn
money begins to be precarious with working people, and these
principally the Government scheme is intended to benefit.

The deposit plan of investing money for assurance is another
system, capable of much modification. In this the interest of
the money purchases a policy or an annuity, and in the event
of death, or previous to death, the principal can be returned.*
Numerous illustrations might be given, some for purchasing
deferred annuities, others for sums payable at fixed periods,
endowments, &c. ; but it is beyond our present object to discuss
them at length.

There are three kinds of Life Assurance offices : — 1st, the
“Proprietary” offices, where shareholders incur the respon-

* A deposit of 100/. at 25 will assure 234/. 10s. 7 d. at death; at 30,
217/. 9s. 5 d. ; at 40, 187/. 10s. A deposit of 6/. 0s. 4 d. at 45, and annually
afterwards, will secure 100/. at death, and the representatives may receive
back all sums paid but the first. A. Scratchley, M.A.

A married couple, of middle age, by saving 3d. a day may secure 100/. to
the survivors, or a like sum to their eldest child when it comes of age.

ON LIFE INSURANCE AND YITAL STATISTICS.

277

sibility and divide the profits, in proportion to the capital they
invest. 2nd, “ Mutual ” offices, where the insurers guarantee
each other to the extent of their funds , and share the profits at
given periods, either in the form of a bonus , or by reducing the
annual premium, or making addition to the sum payable at
death. 3rd, “ Mixed ” offices, in which the assured participate
largely in profits, but have proprietary capital to fall back upon.
The general weight of testimony is in favour of the last system,
for these offices are able to declare larger bonuses than the
Mutual ones, and the cost of a guarantee fund to the assured is
not large. The profits on life assurance depend much upon, —
1st, economy and good management; 2nd, a careful selection of
healthy lives, so that the real result exceeds the calculated
average; 3rd, the prudent investment of funds at interest
exceeding three per cent. But to accomplish this there are
delicate problems to solve : such as— the selection of lives ; the
determination of what amount of stock should be kept in
reserve, to meet payments at a distant date; the amount
required to guarantee perfect safety; the mode of ascertaining
what surplus should be equitably divided, and what proportion
should be divided between share and policy holders ; and the
adjustment of expenses to income. All these are matters which
relate to the finance of life assurance , demanding skill and
experience in this kind of business.

Although, as we have stated, life assurances are calculated
upon the average expectation of persons in the whole commu-
nity, yet the selection of lives is necessary to protect the offices
from fraud, and to render the class of assured lives better than
the general average.

A medical examiner, acting for the interest of the company,
detects the existence of diseases that tend to shorten life. The
duty of these medical experts is to detect those diseases which
bring about an early emergence from the ranks of life; for,
although all must die, the great object of a company is to
exclude all those who are likely to die quickly. No company
could realise any profit where the real expectation of life in the
assured fell much below the calculated expectation, and where
many short-lived persons were permitted to enter.

In the selection of lives, Dr. Mann observes, in one of his
contributions to the medical statistics of life assurance, that it
is of grave importance to be familiar with the waves that rise
and fall below the dead level in the ocean of life, for it is in
these stormy latitudes that the path of their voyage lies.

What specially demands medical attention are facts relating
to the family history, inasmuch as they, more than any other,
throw most light upon the probability of latent disease likely to
shorten life. Suspicious lives are those who show hereditary

278

POPULAR SCIENCE REVIEW.

tendency, or otherwise, to consumption, scrofula, gout, kidney
disease, asthma, heart disease, epilepsy, dysentery, and last,
though not least, intemperate habits.

The admission of consumptive and intemperate persons causes
immense loss to life assurance offices. Lives which become
consumptive after assurance show an average duration of seven
years eleven months, whilst the average expectation should have
been thirty years seven months. The following table shows the
value and expectation of life in temperate and intemperate per-
sons of certain ages : —

Age.

Expectation of
Intemperate
Persons.

Expectation of
Temperate
Persons.

Loss of Life.

Loss per cent.

20

15-8

44-2

27-6

62-4

30

13-8

36-5

22-7

62-2

.40 11'5

28-8 17-3

G0-7

The influence of selected lives is, however, not so great as
may be imagined where large numbers are concerned. The fol-
lowing table shows the annual mortality per 1,000 : —

Ages.

Amongst assured Lives.

Amongst the general
Population.

1st Year.

1st and after Years.

30

40

50

60

70

6£ per 1,000

.8 >2' . ff

14* »

28^

v

8f per 1,000

10f „

16* »

31 „

62* „

10* per 1,000

134 „

17 *

31* »

67

Some persons consider even the present mode of selection
too severe, and that the field of life assurance might be ex-
tended by more general assurance of persons having a standard
average of general good health. The correlation of disease is
a subject deeply interesting in a life assurance point of view.
Scrofula, consumption, cancer, insanity, gout, diabetes, have,
well-known hereditary tendencies; and, where one of these
diseases has manifested itself, another in the category will, very
probably, appear in the individual, or in the offspring.

Hereditary taint cannot be lightly passed over, nor can any
life be considered first-class where it has been well known to exist.

Instead of rejecting, unconditionally and without explanation,
a proposer whose life has been considered doubtful, and where
there is an extra risk, a practice now exists of making surcharges,
that is, to diminish the expectancy of life, and charge the higher

ON LIFE INSURANCE AND VITAL STATISTICS.

279

premium — a practice which general experience appears to indi-
cate to he both inefficient and unsatisfactory.

There are companies which undertake special assurance
against accidental death, in contradistinction to natural causes;
and here subtle questions have arisen, to show how difficult it
is to give any law a general application. Accidental death, in
medical language, signifies mortal effects, produced by a blow, a
fall, poisoning, suffocation, or by violent and sudden means. But
legal difficulties not unfrequently arise, in contesting the nature
of death resulting from sunstroke, lightning, exposure to cold
and privation after or during shipwreck.

Companies are exposed to all kinds of frauds. It may be gene-
rally supposed, that a man has an interest in preserving his own
life ; but experience has plentifully shown, that life assurance
contracts have been deliberately entered into, with a view of
securing for their family that provision which they believed
themselves incapable of obtaining by the usual and legitimate
mode. Numerous instances illustrate the importance of making
a very exact official inquiry as to the cause of death, when it
appears to have been sudden and unexpected. A coroner’s in-
quest is usually a sufficient proof as to the cause of death ; but
its verdict is not binding on any company, and when good rea-
sons have existed for suspecting fraud, facts now and then come
to light that show the death to have been brought about by
poisoning, either accidentally, or from suicidal motives. In-
teresting medico-legal questions, belonging to these cases, em-
brace the many forms of homicide, suicide, and insanity. The
practice, therefore, of making policies indisputable or un-
changeable, after two or three years, adds much to their mer-
cantile value ; for, where fraud, by duelling or suicide, has been
meditated, the claims are early, whilst, in ordinary life policies*
several years elapse.

It frequently happens that a life assurance office meets with
failure. Such a misfortune, however, could never occur under
a prudent management. A guarantee fund need not be large ;
but a provision should be made for rent, salaries, advertising,
and agency, or the expenses will otherwise consume the whole of
the first, and probably, much of the second year’s income from pre-
miums. In a short period, however, the management expenses
ought to bear only a proportion of 2 to 5 per cent, on the pre-
miums, leaving, therefore, a sufficient margin for profit ; for, as
we shall have to show, a charge, or loading, is added to the net
calculated premiums of not less than 20 per cent. There are, too,
circumstances that cause the disruption of a young office, or ne-
cessitate its amalgamation with a more successful rival. In the
first place, mismanagement, and an extravagant expenditure,
with or without an adequate guarantee fund, may do it ; in the

280

POPULAR SCIENCE REVIEW.

second, an interested motive may induce directors, or share-
holders, to effect an amalgamation with a rich and substantial
office — a proposition in no way obj ectionable, when there exists
the least doubt of success, or of permanent stability, to the
affairs of a young company.

Fraud, and various other kinds of irregularities in life as-
surance offices, are to be attributed, when they do occur, to
directors either being too much engrossed in their own affairs, or
understanding too little of those of the company, to enable them
to form an opinion upon its financial position. Hence the
utility of that very useful class of men — actuaries, auditors, and
accountants. A system of audit by men of great experience
and sagacity is, indeed, most essential in every life assurance
office. Experience also shows that legislative interference may
wisely be used to protect the interests of private individuals,
who are now so largely disposed to invest in our numerous
mutual and co-operative associations. Auditors elected by
shareholders themselves are often unsafe, their investigations not
extending sufficiently into details. In calculating risk, and the
many financial investigations contingent upon life, the highest
mathematical and scientific education is necessary to get at true
results ; and none but an experienced and trained actuary can,
with a prospect of success, undertake these duties. We coincide
with Dr. Farr, that a settled system of annual audit should be
instituted, and such returns made to Grovernment as shall enable
sound offices to establish, without a doubt, their ability to fulfil
their engagements.

Much more might be written to illustrate the connection of
life assurance doctrines with co-operative industrial associations,
investment of savings, freehold land and building societies,
and their adaptability for the better regulation and security of
friendly societies; and lastly, it' may be predicted that a time
may arrive, when it will be considered a national duty to enforce
a tax upon the whole population, to meet the social miseries
arising from improvidence, sickness, accidents, sudden and un-
expected emergency into the less favoured ranks of life ; rather
than submit to the inequalities and unfairness of compulsory
rates on the property and industry of a few. The poor rates
are a burden upon the industrial energies of the middle class,
and fail in their object ; for, neither in theory nor in practice
will they keep large numbers of people from destitution, even
in this rich country. Men should legally endow themselves ; for,
just as security is the foundation of civilisation in a state, the
adoption of measures by individuals to mitigate the effects of
prospective misfortune, is the best foundation of social pros-
perity.

281

THE HEW ELECTROMAGNETIC MACHINES.

HE able disquisition upon the conversion of motive force

into electro-magnetism made by Mr. Wilde in his paper
last year before the Royal Society, gave an additional impetus
to other electricians to make advances in the same direction,
and both Mr. C. W. Siemens and Professor Wheatstone have
since described original views and exhibited models of machines
constructed upon their respective principles. Mr. Ladd, too,
the eminent philosophical instrument maker, of Beak Street,
also produced before the Royal Society, in a practical model, a
long-conceived idea of his assistant, Mr. Tisley, a few evenings
after the exhibition, at the president’s soiree, of the magnificent
10-inch machine of Mr. Wilde’s. Mr. Ladd has now a larger
machine of two-horse power at the Paris Exhibition ; and at
the recent soiree of the Civil Engineers there was at work one
of Mr. Siemens’ beacon apparatus for flashing lights.

Of all these plans, however, Mr. Wilde’s is the only one that
has been practically put to the test on the large scale. We
therefore begin our review with a description of that magnifi-
cent machine we have had the opportunity of seeing develop
such a torrent of electrical force. Whether this force be utilised
in its intensity as light, or its quactity used as a heating power,
what Mr. Wilde has shown causes the strongest convictions to
arise in the mind that electricity generated by engine power
will be amongst the practical operations of future industry,
and will take a rank no one has hitherto conceived.

We are all of us familiar with the electric light as supplied
by the currents from various kinds of voltaic batteries in which
chemical action gives rise to a continuous flow of electrical force.
All of us, too, are familiar with the conversion of magnetism
through its intensification in the induction-coil into luminous
electric sparks. And, finally, very few indeed there must be
who did not see Mr. Holmes’ magneto -electric light in the Great
International Exhibition of 1862, in which the currents were
gained from numerous keepers set on the periphery of a large
wheel passing between the poles of a corresponding circle of

By S. J. MACK1E.

282

POPULAR SCIENCE REVIEW.

fixed magnets. This fine light had before then sent its piercing
rays for a considerable period across the English Channel, and
its bright beams, projected from the lighthouse of Dungeness,
had been the admiration of so many gazers on the shores of
France. Mr. Holmes’ revolving wheel was a somewhat cum-
brous way of getting the electric power, and some important
modifications of this means have been made in France.

After some years Mr. Wilde struck out a plan more powerful
and less liable to derangement, and which, though ponderous as
a machine, is far more compact than its predecessors. His
principle is in one sense the reverse of Mr. Holmes’. Instead of
an army of small keepers revolving against a circle of batteries
of small magnets, he causes one gigantic keeper to revolve inside
a huge electro-magnet — a revolving canal draining a saturated
mountain — kept at the point of saturation by a separate charging
battery of permanent magnets.

The action and power of Mr. Wilde’s machine will be best
understood by a general description of its parts and their separate
and combined actions. The main and most prominent portion,
that which not only does the most work but most attracts the
eye by its massive dimensions, is the electro-magnet ( u , x , u).
This consists of two vertical plates (u, u) of rolled iron, 4 feet
in length and 3 feet 3 inches wide; in thickness 1^ inches.
Each of these is coiled with 4,800 feet of insulated cable of 13
strands of copper wire 0T25 inch in diameter ( t , t), the total
weight of the coils being over 1 \ tons. Instead of the soft iron
core being turned over in an arch, as in the common smaller horse-
shoe magnets, these two flat sides are connected together at the
top by an iron slab or hollow bridge ( x , x), 1 foot 4 inches
across. At the base of the electro-magnet and upon which its
massive sides are secured, is the magnet-cylinder ( b ' b', c' c'), con-
sisting of two large cast-iron segments ( b ' b' and c' c ') magneti-
cally separated in their entire length by intermediate mechanical
connections of brass ( d ' d'), which form with them one cylindrical
case in the bore of which the enormous Siemens’ armature
(s' s s' s'), 10 inches in diameter, is made to revolve. Upon the
top of this powerful electro-magnet is stationed a battery (a) of
20 permanent magnets, each of which is capable of sustaining a
weight of 20 lbs. The magnet-cylinder for this adjunct is formed
in the like manner of two segments of cast-iron (6) mechanically
joined by blocks of brass ( d , d), which metal not being a magnetic
conductor effectually insulates the two iron segments, whilst it
combines those two separate parts into one entire piece of
machinery. The armature (g) which revolves within this
magnet- cylinder is 3-| inches in diameter, and is wound round
longitudinally about an iron core by 80 feet of covered copper
wire. Such is the machine. Now the object of its action is to

Dynamic Magneto-Electric Machines

THE HEW ELECTRO-MAGNETIC MACHINES.

283

change common dynamic or motive power into electricity. To
this end a steam-engine of 15-horse power is employed to drive,
by means of leather bands, the armatures of the magneto-
electric (a) and electro-magnetic (x, d) portions. The armature
(i g ) is the first or magneto-electric machine ( a ) ; is driven at the
rate of 2,000 revolutions per minute ; and as both portions of the
armature are thus presented to the poles of the magnetic battery
during each revolution, 4,000 waves of electricity are transmitted
per minute to the steel studs of the great electro-magnet ( x , w, u)
exciting it to intense action and keeping it constantly highly
charged with magnetic influence. Whilst so excited its huge
armature revolves with the rapidity of 1,500 revolutions per
minute, thus supplying 3,000 waves of electrical force for any
required practical purpose, such as the maintenance of a
powerful light, or the heating of metal bars or wire, or the ex-
ercise of magnetic attraction, this great electro -magnet being
capable under the last condition of sustaining a weight of 50 tons.
The armatures used in this electro-magnetic portion measure
52 inches in length and are of two kinds, one for intensity, used
in the production of light, the other for quantity, used for the
production of heat. The intensity-armature is wound round
with 376 feet of insulated cable of 13 strands of covered wire
the same as that wound round the electro -magnet itself ; the
quantity-armature has an insulated conductor composed of 4
plates of copper, each 67 feet in length, 6 inches wide, and j^th
of an inch in thickness, superposed in metallic contact. The weight
of the armature-intensity coils is 232 lbs. ; that of the insulated
plates in the quantity-armature 344 lbs., and its total weight
more than a quarter of a ton. The principle developed by Mr.
Wilde is that by charging the large electro-magnet by means
of the magneto-electric battery with as nearly as possible the
quantity of magnetism it is capable of imbibing, and by means
of this adjunct maintaining constantly this full charge, the maxi-
mum electrical current can be drawn off by the Siemens’ arma-
ture (s' s') from the electro-magnet* ( x , u, u ). The increase of
power so obtained is continuously as far greater than that which
is obtainable from revolving the same armature in an uncharged
or partially charged magnet as the cube of the saturation is to
the cube of the residual magnetism naturally contained in the
iron of the magnet.

The experiments performed with Mr. Wilde’s large machine,
during the time it was stationed in the lower library of the
Eoyal Society, were most interesting and marvellous, although
necessarily they were restricted in variety by the absence of
auxiliary philosophical apparatus of anything like sufficient size
or capacity for receiving such an unrivalled stream of electrical
force, and consequently the chief display of its powers consisted

284

POPULAR SCIENCE REVIEW.

in developing its powerful light, and in the heating and fusing
of bars and wires of various lengths of different metals. This
light as shown in the library presented most remarkable features,
and was strong enough to make itself powerfully supreme over
the brighest daylight of that period of the year — February. It
was generated from stout carbon points over a foot in length,
and half an inch square ; and when concentrated by a polished
reflector, a beam of white light, 2 feet in diameter, issued forth
glittering upon every object in its gradually widening path with
more than the brilliancy of sunshine. Around the white central
beam was an outer cylinder of bluish light, within the region of
which, blue, violet, and mauve coloured ribbons and dresses ex-
hibited the like exquisite intensification of hue as when under
the rich rays of magnesium. Only one feature in the light was
even seemingly at all objectionable, and this was a certain
exceedingly rapid flicker ; but scarcely noticeable when the back
was turned upon the source. This flicker is, however, peculiar
only to this particular machine, and is not observable in the
smaller 7-inch or 5-inch machines which have been made by
Mr. Wilde ; it could be overcome in the present one by an
acceleration of the speed of the armature from 1,500 to 2,000
revolutions per minute, or by the use of a commutator to send
the electrical currents in one direction. In no way is it a
defect, for when the light is diffused out of doors, this tremu-
lousness is not perceptible at a short distance away; as for
example, when it was displayed from the top of Burlington
House, the flicker was not noticeable at the gateway of the
court-yard, where at night I distinctly read the small brevier
print of one of the popular sixpenny editions of Cooper’s u Water-
Witch,” and obtained distinctly the shadow of the flame of a
lucifer-match on the back of my invitation card. The reason
for not using a commutator, is that something of the force of
the current would be lost ; opposite currents are therefore
allowed to alternate at the carbon points with immense rapidity,
and what we really see in the flicker of the light is the flash,
first of a current downward from above, and then the flash upwards
of a current from below. These reversals, accomplished 3,000
times a minute, are appreciable by the optic nerves, but at 4,000
times would not be so. It is, however, no defect, as we have
said, in the penetration, volume, or practical value of the
marvellous beam. It was also wonderful to see the actual flames
dashing out around the incandescent points of the carbons.
The spectrum of the arc of light between the carbons (which
were kept by a Dubosq lamp within less than a quarter of an
inch of each other), as seen through a Browning’s direct vision
spectroscope, was most gorgeous, the lines of burning iron,
sodium, and other impurities in the carbons coming out with the

THE NEW ELECTRO-MAaNETIC MACHINES.

285

greatest brilliancy, as also did a splendid bluish line far in the
violet portion, and probably due to the incandescence of the
nitrogen of the air.

When the carbons were placed horizontally between the
actual terminals of the machine, without any reflector whatever,
the light was diffused all over the room with the most agreeable
softness, nothwith standing its intensity, and a modification of
some such natural method would appear to be an excellent one
for illuminating large squares and other public open spaces.
Even in broad daylight Mr. Wilde’s electric light had the
power of throwing the distinct and beautiful shadow of a
burning wax candle on a screen upon the wall 50 feet distant,
marking out with exquisite perfection the gaseous core of the
flame, bordered by a bright outline of the section of the flame
itself, whilst the small inner flame, at the extreme point of the
wick, was also shown in darker shadow, outlined with a fainter
line of light. It cast the shadow of the flame of burning
magnesium as black as night upon a wall eight feet distant, an
evidence unmistakeable of the superior intensity of the electric
beam, for supposing the shadow to have been that of dense
fumes within the flame, it must not be forgotten that one side
of the magnesium fire was still throwing all its powerful rays
upon the screen over its own shadow, produced by the more
distant electric light.

The heating power of the machine was shown by the fusion
of a bar of iron, 15 inches in length, and more than a quarter of
an inch thick ; whilst upwards of 7 feet of ordinary iron wire,
such as is used for the fencing of fields, was brought to white-
ness, and along its entire length tears of molten metal trickled
fast and freely down, until the attenuated wire broke, and fell
upon the floor.

The most marvellous exhibition, however, was the actual
fusion of a bar of platinum, 18 inches in length, and 0*21
inch in diameter. The high temperature at which platinum
can only be melted is very well known. Indeed, it is by the
oxy-hydrogen blast alone that platinum can be commercially
prepared. A bar of platinum, 030 in diameter, was afterwards
fixed to the terminals, 9 inches apart, and maintained for a
short period at incandescent whiteness, but fusion was not
allowed to take place, the platinum being rather too expensive
a material to play freely with. The bar thus experimented
upon was in value about £25.

Of the effect of the current from Mr. Wilde’s machine when
sent through an induction-coil, some indication was given
in the effects produced upon a large instrument which had
been prepared by Mr. Ladd for a smaller electro-magnetic
machine. This coil consisted of four miles of No. 27 copper wire,

286

POPULAR SCIENCE REVIEW.

0*017 inch diameter, the usual wire for ordinary large coils
being No. 35, diameter 0’008 inch. The current from the
intensity-armature of Mr. Wilde’s machine was sent through
the primary wire, the induction current being then shown across
the points without any condenser being used. The current was
sent from the big armature for a few seconds only, Mr. Ladd
being naturally afraid of damage to his instrument. The re-
sult was a perfect arc of flame which, if measured in its full
high bend, would be at least 4 inches, the carbon points attached
to the terminals being 2 inches asunder. When a platinum
break was used with this coil for but an instant, the combustion
was so great that with about a dozen flashes it so fused the ends
of the platinum rods as to make the distilled water in which
they were immersed like ink with the solution of the metal.

Mr. Wilde’s magnificent machine is a practically accomplished
fact, and we are glad to know that a 7 -inch apparatus is about
to be set to work for the Commissioners of Northern Light-
houses.

We have next to consider the several other important models
and propositions. The first of these is the proposal by Mr.
Siemens to take the electrical force direct from the electro-
magnet without any previous separate charging by a distinct
magneto-electric machine. Mr. Siemens has found that after
imparting the slightest magnetism to an electro-magnet — and
there is always sufficient residual magnetism for the purpose —
the armature can be made to intensify it and to impart at each
revolution a higher charge to the magnet, thus absorbing at each
turn more and more magnetism and returning a more and more
intensified current into the magnet, causing in this way, by its
own action, an incessant augmentation of force until the power
of the magnet would become sufficient to arrest the action of
the machine by overpowering the force employed to drive it, or
by heating the coil around it to a degree that would injure the
insulating cover of the wire.

Mr. Siemens’ machine consists of a battery of electro-magnets,
within which a coiled armature is rapidly rotated in the same
way as within Mr. Wilde’s large electro -magnet, the difference
in the two machines being that Mr. Siemens’ periodically and
alternately charges and discharges the accumulated magnetism,
whilst Mr. Wilde continuously withdraws the full electric force
from his electro-magnet and as constantly refurnishes the electro-
magnet with electricity by a separate magnetic machine acting
independently but simultaneously. Mr. Siemens proposes to
utilise his invention by conveying the current from the machine
ashore by a submarine cable to beacons and light-vessels afloat,
on board which it will be accumulated and intensified in a
suitable induction-coil. A keeper attached to one end of a

THE NEW ELECTKO-MAGNETIC MACHINES.

287

lever is balanced at the other end by a heavy weight. When
the induction-coil is fully charged, its magnetic attraction will
drawdown the keeper, and the contact of a platinum point with
a cup of mercury is broken at the opposite end of the lever, a
bright flash being emitted. The accumulation of electricity
again goes on in the induction-coil until the keeper end of the
lever is again depressed, contact broken at the opposite weighted
end, and the flash repeated ; and so on continuously. By means
of clock-work arrangement, and an excentric plate • dipping
periodically into the mercury contact, the transmission of the
current from the land machine can be delayed for definite
intervals, and by such periods, combined with the intermittent
flashes, the beacon can be made to optically speak its name in
unmistakable terms and to convey its needed warning to every
mariner. The commissioners of Northern Lights and some of
the authorities connected with the Southern Lights have already
entertained the project.

Professor Wheatstone has also proposed a similar method for
the direct conversion of dynamical into electrical force founded
on the like gradual augmentation of the slightest polarity into
a powerful magnet. The construction of Mr. Wheatstone’s
model is this. The case of the electro-magnet is a plate of soft
iron 15 inches in length and half an inch in breadth bent into
a horse-shoe form and coiled round by 640 feet of insulated
copper (-jL-th inch) wire. Within it is a rotating Siemens arma-
ture 8J inches long, coiled longitudinally with 80 feet of wire
like that on the electro-magnet. Professor Wheatstone shows
the existence of an energetic current by heating 4 inches of
platinum wire *0067 inch diameter. This heating power is
obtained by making a short circuit through the wire and is
temporarily of great intensity but quickly subsides; and a
current can then only be maintained equal to keeping one inch
of the wire at a red heat.

Mr. Ladd’s first model consisted of two plates of soft iron
(A, B) about 7^ inches in length, 2J inches in breadth, and \
inch thick, placed horizontally, with a Siemens rotating arma-
ture between them at each end (EE, HH). Over each of these
plates about 30 yards of insulating wire (No. 10) is coiled
[kkk k). The armature at one end ( h h) acts in connection
with a magnet or piece of soft iron, having a slight quantity of
residual magnetism. The current from this armature charges
the electro-magnet (ab). The second armature (ee) at the
other end of the electro-magnet takes off the electricity which
is conveyed by copper wires to two fixed terminals (s s), whence
it is applied to the practical purpose required. The power of
this little model is very great, and sufficient to maintain three
inches of platinum wire (*01 inch diameter) at a white heat.

VOL. vi. — NO. XXIV. Y

288

POPULAR SCIENCE REVIEW.

A valuable suggestion has been made by Mr. Tisley for eoiling
the armature rotating within an electro-magnet with two
distinct wires so arranged that the terminals of one being in
connection with the electro-magnet supplies a current to charge
it whilst a current is carried off by the other wire to do the
practical work required of the machine.

The machine in the Paris Exhibition has two armatures
measuring 12 in. long 2^ in. diameter; when arranged for
quantity, it will give 250 cubic centimetres of mixed gases
per minute. It has melted 18 in. of platinum wire 1 millimetre
thick, and will maintain 4 feet 6 inches of wire 0*01 diameter
persistently at white heat.

In these machines the conversion of the dynamical or driving
power is direct and seemingly suffers comparatively but very
little loss, and this feature is well shown in the sensitive fluctua-
tions of the incandescence of the platinum wire between the
terminals in consonance with the variations of the speed.

The final success amongst all these various and future plans
will be in favour of that which will yield the most economic
utilization of the primary dynamical power, and that will do this
without inconvenience or delay from the swelling of the arma-
tures, heated by the magnetic friction when rapidly rotated.
The charge sent into the electro-magnet must almost be con-
trolled within proper proportions, otherwise there will be a gain
of resistance that will accumulate in the machine until it
equals or overcomes the motive power. Something has been
already done in this last direction by the magnetic shutter, pro-
posed by Mr. Tisley and which being proportionately slid over
the ends of the plates ( k 1c) partially cuts off the magnetism
acting upon the generating armature, at the same time that it
gives improved effect in the armature for external work by
completing the horse-shoe form of the magnet. In this way
the power to work it can be regulated from two men to two
horses, the total result produced of course depending upon the
power primarily applied. These practical electrical subjects
are already deeply occupying men’s minds, and their pursuit
must bring forth good fruit. In a few years, perhaps sooner,
it will be our duty again to come forward to describe other new
electrical machines.

Botany of a Coal

Mine

THE BOTANY OF A COAL MINE.

By WILLLAM CABEUTHEKS, F.L.S.

IT is the practice to speak of the known plants of a particular
geological period as a Flora, but the use of the word is apt
to convey a very erroneous impression of the extent of our
acquaintance with the plants that actually existed during the
time that the rocks of the period were being deposited. No
stranger would venture to designate the description of a hundred
of our more common plants, collected during a visit of a few
hours to our shores, as a “ British Flora.” He may have
diligently employed his opportunities, and collected an unusually
large number of species in the short time at his command, but
at the best they would only be contributions to the greater work.
One expects to find in a Flora some approach to a description of
all the species found in the country.

The list of plants which constitute the Coal Flora has been
considered as giving a fair representation of the vegetation of
that period, but a little reflection will convince us, that from the
nature of the case only a small proportion of the plants then
flourishing could have withstood the numerous agencies which
produced their destruction. The chief of these agencies was water.
The roof shales, in which have been preserved the great propor-
tion of the determinable remains of the plants, were mud deposits,
and the water which deposited this mud must have saturated the
loose vegetable matter below. Water speedily breaks up and
destroys vegetable tissues, reducing them in the end to an
amorphous pulp. Lindley has by experiment shown that all
plants do not yield in an equal degree to this influence. He
placed 177 specimens belonging to various natural orders into
a vessel of fresh water. At the end of two years 121 had
entirely disappeared, and of the 56 that remained, the most
perfect specimens were those of Coniferse, Palms, Ferns, and
Lycopodiaceas. It follows then, that a varied vegetation placed
in the conditions under which the coal beds were formed
would leave no recognisable remains, while they nevertheless
might contribute greatly to the amorphous coal mass itself.

The record of the Flora of the coal measures is further

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rendered defective, by the limited extent to which even those
plants that are preserved in the rocks have been examined hy
man. And if this is true of the carboniferous period, it is much
more so of all the other life systems, whose only records are to
be found in the crust of the earth, for the economic value of the
plant products of this period have brought under observation a
larger proportion of their remains than of those of any, we may
almost say, of all the other geological epochs. Yet, how little
of the 100,000 tons of coal annually brought to the surface in
Britain, is ever scanned by the palaeontologist. It is often the
merest accident that has led to the discovery of a new form,
as for instance, fine and rare specimens have sometimes been
disclosed by the splitting of the coal, when it was being con-
sumed, and have been saved from destruction by the accidental
glance of an educated eye. But, while the coal is brought to
view, and a chance is given to examine its contents, the shales
which contain the more perfect remains are left by the collier to
form a secure roof to his mine.

No less than 300 species of plants have been described from
the rocks of the Coal period in Britain. Many of these are,
however, established on imperfect materials. The specimens
are so fragmentary that it is difficult to determine the various
portions that belong to the same plant. The root is rarely
connected with the stem, the stem with the branches, or the
branches with the leaves or fruit ; consequently all these parts
have been referred to different genera, and have received
different names. With increased materials, and additional
observations, the means are occasionally turning up, which enable
us to reduce some of these genera, and while new forms are
being described, the tendency of modern research is rather to
decrease the number of genera and species. We shall have
to adduce abundant evidence of this* in the course of our
paper.

Eliminating, as far as possible, the genera that have been
thus erroneously founded on imperfect materials, it is remarkable
to what a small number of forms the plants of the coal measures
may be reduced. Ferns, and the fossils to which the generic
names of Sigillaria , Lepidodendron, Catamites, and Dadoxylon ,
have been given, comprise almost the whole of the known Flora.
Nearly half of the species described are ferns, but they do not
seem to have contributed to any great extent to the formation
of coal ; for while their vascular tissue does not easily decom-
pose, their remains are extremely rare in coal, and they are
chiefly known from the occurrence of their fronds in the roof
shales. Two or three arborescent ferns have been' observed,
but the great majority seem to have been herbaceous plants,
which flourished on the margins of the lakes that covered the

THE BOTANY OF A COAL MINE.

291

submerged forests, or on the banks of the rivers that brought
down the mud in which they are preserved.

The vascular tissues found in the coal, or seen in the film of
charcoal, or so-cafled “ mother-coal,” that separates the coal into
layers parallel to the surface of the seam, belong all to one or
other of the genera mentioned. The absence of foliage, and of
cellular plants might have been expected from the experiments
of Professor Lindley, to which we have alluded. Many deposits
of peat are composed almost entirely of cellular plants, and
as the moist atmosphere, which necessarily prevailed in the
extensive forests that covered the great areas now forming the
coal fields of the Old and New Worlds, was specially fitted for
the luxuriant growth of cellular parasites, such as lichens and
mosses, it is probable that these simpler forms greatly helped
to make up the amorphous substance of the coal. We could
not expect the structure or forms of these to be preserved. The
only cellular plants of the coal measures — species of polyporous
fungi — have been shown by Mr. Binney to be the thick ganoid
scales of a fish.

Parasites having a higher position in the vegetable kingdom
than cryptogams may have flourished on the trees of the
carboniferous forests — parasites analogous to the orchids and
aroids of tropical forests. A confirmation of this opinion may
be found in the only certain specimen of an angiospermatous
phanerogam which has been found in the coal measures, and
which from its resemblance to the inflorescence of some recent
Aroidese its discoverer Dr. Patterson named Pothocites.

In examining the principal forms of the Coal Flora we need
do little more than refer to the ferns. Not only do the fossil
species obviously belong to this order, blit some of the forms do
not apparently differ from genera now living. The fructification,
when it is present, the venation, and the few specimens in which
the circinnate venation has been preserved, show that in their
structure and economy the palseozoic species agreed with their
modern representatives. The chief difficulty that besets this
study is the almost invariable absence of the fructification, upon
which the modern classification of the order is chiefly based.
Brongniart has employed the venation, and in the absence of
fruit the best characters are to be obtained from it ; but the
examination of a large series of recent species shows, that many
forms widely separated systematically, have similar venation.
The general outline of the frond has also been used for obtain-
ing specific characteristics, but among living forms a great
variety in this respect occurs. It is probable that on account
of errors from the necessarily unsatisfactory materials for classi-
fication, the number of species has been greatly overestimated.

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and on the other hand that some really different plants have
been united under a single species.

• The plants which have contributed most largely to the
formation of the coal, are those included in the genus Sigillaria.
Their fluted trunks and tuberculated roots are among’ the first
fossils that a student observes in a visit to a coal field. The
roots ( Stigmaria ) were long a puzzle to botanists. They were
observed to proceed from a large central and apparently perfect
66 cup or dome,” and, dichotomously dividing, they extended to
a great distance in the shale in which they were preserved
in a singularly perfect condition. Lindley and Hutton, after
examining several perfect specimens, as they supposed, during
the progress of their “ Fossil Flora,” gave up their original
opinion, that it was a prostrate land plant, and considered it in
the end, as a huge aquatic plant, growing on the soft mud at
the bottom of still lakes. Brongniart, from a consideration of
the structures of the two genera, suggested that Stigmaria
might be the root of Sigillaria ; but the first step to a positive
determination of the true nature of the plant was made by Sir
William Logan, when he observed in the South Wales coalfield
that every bed of coal rested on a layer of under clay, which was
full of Stigmaria , and the relation suggested by Brongniart
was established by Mr. Binney, who traced the connection
between the sigillarian trunk and the stigmarian roots in a
quarry at St. Helen’s, in 1843.

The supposed leaves which are given off by the roots through-
out their whole course and from every portion of their circum-
ference, are rootlets composed entirely of cellular tissue, except
a slender bundle of vessels which passes through them. These
rootlets have been traced to a length of twenty feet.

Although specimens of Sigillaria are so abundant, they are
so imperfect that less is known of this genus than of almost any
of the other coal plants. It is doubtful whether the trunk was
simple or branched, and whether the foliage was composed of
linear leaves or fernlike fronds, and nothing whatever is known of
its fructification. It is consequently not to be wondered at that
very different notions have been entertained of its systematic
position. By Lindley and Hutton, and by Cordau, it was re-
ferred to Euphorbiacece , by Schlotheim to palms, by von Martius
to Cacti , by Sternberg to ferns, by Brongniart to a position in-
termediate between Lycopodiacece and Cycadece , by Hooker to
Lycopodiacece , by Dawson to Cycadece , and lastly, Groeppert who
has spent a long life in the study of fossil plants, writes, within
the last few months, that its true position has not yet been
determined.

Both Brongniart and Binney have described the internal
structure of supposed species of Sigillaria , but the external

THE BOTANY OF A COAL MINE.

293

markings, which are the only characters by which Sigillaria
and Lepiclodendron can be separated, show that the fossils so de-
scribed were nearer to, if not genuine species of, the latter genus.
In the absence, however, of stems showing structure, several
specimens of Stigmaria have been found in which the various
tissues have been preserved. In a beautiful series forming part
of the collection of the late Eobert Brown, I have traced the
various parts. The axis was composed of elongated scalariform
cells. Around this was a compact cylinder of scalariform vessels,
perforated by bundles, which passed to the rootlets, but without
any trace of medullary rays. This was surrounded by a con-
siderable mass of cellular tissue, forming the great bulk of the
root, through which passed the bundles to the rootlets.

The scalariform tissue and the absence of medullary rays are
of importance in estimating the systematic position of the fossil,
and these both clearly point to its being a true cryptogam. As
the structure of Stigmaria agrees with what is known of the
stems of species described as Sigillaria elegans , S. vascularis ,
Lepiclodendron Harcourtii , &c., there can be no doubt that it
exhibits the true structure of Sigillaria itself. It is true that
Dawson refers to this genus a stem composed chiefly of disc-
bearing woody fibre, but it is not evident from either the
drawing or description, that this remarkable stem really belonged
to Sigillaria ; and it differs so much from the known structure
of the roots as well as of the allied forms named that we hesitate
to place it there. The medullary rays described and figured by
Brongniart have not been seen in any other specimen, and an
examination of his beautiful drawings convinces me that the
interspaces between the vascular tissue, which he has described
as medullar}^ rays, are accidentally produced by the splitting up
of the tissues. He found no indications of the walls of the
medullary cells, which would certainly have been apparent in a
fossil so perfectly preserved as his Sigillaria elegans .

All that is certainly known of Sigillaria , tends to establish
the opinion advanced by Hooker, that it is allied to Lepido-
dendron , and consequently belongs like that fossil, as we shall
presently see, to the order Lycopodiacece.

The extent of our acquaintance with Lepiclodendron is in
singular contrast with what we know of Sigillaria. The only
part of the plant about which there is the least uncertainty is
the root. The stem, branches, foliage and fruit are all well
known.

Lepiclodendron was a branching tree of considerable size.
It is distinguished from the other genera of coal plants by the
lozenge-shaped leaf scars being arranged spirally on the stem.

The axis of the stem (pi. xvi. fig. 12) is composed of elongated
utricles of various sizes, irregularly arranged, and having thin

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walls marked with scalariform bars. This is so different a
structure from the pith of a dicotyledon that it can only be
compared to it from occupying the same position in the stem.
It is surrounded by a compact cylinder consisting of long sca-
lariform vessels, which somewhat increase in size from the inner
margin to the outer, this increase being sufficient to meet the
requirements of the enlarged circumference, with the addition
of only a few series of vessels. As there is no true medullary
cellular tissue in the axis, so there are no medullary rays passing
through the woody cylinder ; it is however penetrated by the
vascular bundles which supply the leaves which have been
mistaken for or misnamed medullary rays. The woody cy-
linder is surrounded by a great thickness of cellular tissue,
which extends to the exterior of the stem and is composed of
three distinct and separable layers. The inner zone has never,
as far as I know, been perfectly preserved in any specimen, yet
traces of it may be occasionally seen. Its absence arises from
its extremely delicate structure. The cells of the middle zone
have thicker walls, and have consequently more frequently
resisted decomposition before fossilisation made them permanent.
In the outer zone the cells are very much lengthened, and have
a smaller diameter, resembling very closely true woody fibre.
The cell walls of the three zones are without markings of any
kind.

The vascular bundles which pass through the woody cylinder
traverse these cellular layers to the leaves and branches. Each
bundle consists of scalariform vessels very much finer than those
of the wood of the stem, surrounded by elongated cells like
those of the outer zone, and probably still further by a delicate
parenchyma, which disappeared before it was fossilised. The
only evidence I have of the existence of this cellular tissue is
that the bundles never fill the cavities in the tissues of the stem
through which they pass. The vascular bundles terminate in
the points seen on the areoles of the stem, which are the scars
of the bases of the leaves.

The woody cylinder is of different thicknesses in different
stems, and appears to have increased with the growth of the
tree; there is however no indication of interruption in the
growth or of seasonal layers ; but the whole cylinder could not
have been developed at the same time. It is very probable
that the zone of slender and consequently rarely preserved
cellular tissue which surrounded the woody cylinder was analo-
gous in its functions to the cambium layer of phanerogamous
stems, like a similar structure which occurs in recent Lyco-
podiaceoe.

The leaves were simple, lanceolate, acute and sessile. They
had a single median nerve. The younger branches were

THE BOTANY OF A COAL MINE. 295

densely covered with leaves ; and the scars left on the trunk
after they perished give the beautiful markings by which the
different species are distinguished. The leaves when found
separately are called Lepidophylla.

The fruit was a strobilus ( Lepidostrobus ) (pi. xvi. fig. 1)
formed from a shortened branch, the leaves of which are
converted into scales that support on their upper surface a
single large sporangium (fig. 4), which appears to contain both
macrospores (fig. 5) and microspores.

These sporiferous strobili can scarcely be distinguished in
general appearance and arrangement of parts from those of
some recent Lycopodiacece , except in the great difference of
size, but their containing two kinds of spores indicates an affi-
nity rather with Rhizocarpece.

Another cone (Flemingites, fig. 2), having the same external
appearance, occurs in the coal measures though it has not yet
been found connected with any supporting plant. Its sporangia
(fig. 3) occur in enormous quantity in many coals, and the tree
on which it was borne — probably one of the lepidendroid forms —
must have been very abundant, and contributed largely to the
formation of coal. It differed from Lepidodendron in having-
numerous small sporangia supported on each scale.

The structure of the stem also confirms the near affinity of
'Lepidodendron to our living vascular cryptogams. In general
arrangement of parts they agree indeed more with Gycadece , and
thus appear to support the views of Dawson in regard to Sigil-
laria , but the minute structure of the vascular tissue and the
absence of medullary rays are much more important characters
than the modifications in the arrangement of the constituent
parts of the stem, which is often very different in the same
order of plants. A comparison of the fossil arborescent trunk
with the slender stem of a modern lycopod shows that the prin-
cipal differences are the existence of a pseudo-medulla, and the
arrangement of the vascular tissue as a solid cylinder in the
fossil genus as against the central position and loose structure
of the vascular tissue in the recent plant. In both the recent
and fossil stems the vascular tissues are surrounded by a zone of
thin walled cells, which has disappeared in all the dried speci-
mens of Lycopodium I have examined, leaving the axis free,
and which, as we have seen, is very rarely preserved in Lepido-
dendron.

Perhaps more genera have been established for the different
parts of Catamites than for the fragments of any other fossil
genus. The stem has been described as Catamites , Calamitea ,
and Catamodendron ; the foliage as Aster ophyllites, Annu-
laria , Hippurites and Sphenophyllum , and the fruit as Volk
mannia, Aphyllostachys , Huttonia , &c.

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The axis of the stem of Catamites (pi. xvi. fig. 13) was com-
posed of cellular tissue, and this was surrounded by a solid
cylinder of wood entirely composed of scalariform vessels, and
without any trace of medullary rays. The vascular tissue was
developed from a series of equidistant points near the circum-
ference of the cellular tissue, and grew outwards and laterally
until they united in a continuous cylinder fluted on the inner
surface and with the flutings filled with the cellular tissue of
the axis. A similar structure exists in the arborescent stems of
some species of Cactus . There were constrictions at regular
intervals in the woody cylinder, as in some recent Avtocarpece,
The wood was covered by a thin epidermal layer of parenchyma,
which is less seldom preserved than the cellular structure of the
axis.

The stem somewhat rapidly contracted at the base, the nodes
shortening, and giving off long cylindrical roots which spread
laterally through the soil.

The main stem was simple, but at intervals gave off whorls
of slender branches, and these again bore branches or leaves
also arranged in whorls. The leaves were capillary (Astero-
phy llites ) linear-lanceolate ( Annularia , and Hippurites ) or
cuneate ( Sphenophyllum ) and each whorl contained, in different
species, from five to twenty leaves.

The fruit was a strobilus (fig. 7) composed of whorls of
scales alternating with and protecting whorls of peltate leaves,
which supported the sporangia (fig. 4). The spores were simple
and not compound as in Lepidostrobus.

Various opinions have been entertained regarding the sys-
tematic position of Catamites . It was originally supposed that
they were huge Equisetacece , from the jointed and fluted stems.
But these characters, which have been always described as
external, are really on the interior of the woody cylinder.
Catamites occur fossil either as cylinders of coal, the empty
cellular core filled with sand, clay, or other foreign substance,
or more frequently as flattened stems with more or less foreign
matter in the interior, or more rarely preserved in calcareous
or ironstone nodules and preserving to some extent the original
structure. When the plants were destroyed the cellular axis
speedily disappeared, and the woody cylinder alone formed the
layer of coal. The cast of the interior, which in time became
harder than the vascular tissues of the stem, acted upon as it was
by the water that saturated the deposit, resisted more success-
fully the pressure of the superincumbent deposits which in
compressing the stem produced on its outer surface a counter-
part of the furrows and constrictions of the internal cast. The
outer surface of the stem was entirely free from these markings,
so that the affinity to Equisetece derived from them is valueless.

THE BOTANY OF A COAL MINE.

297

Is is singular however, to find that after being referred by some
to Grymnosperms, and by others placed among the incertce
sedis, the structure of the fruit shows that they really belong
to the family to which at first, though on false observation, they
had been referred. The stem, which as in Lepidodendron
and Sigillaria in respect of their modern representatives, is
anomalous when compared with the slender stems of recent
equisetums, is yet only such a modification as would be re-
quired for arborescent forms of the order.

While the remains of Coniferce as distinct and recognisable
fossils are rare in the coal measures, the abundance of coniferous
structures in the “mother coal” shows that they formed a
considerable proportion of the forests which flourished during
the Carboniferous period. Large trunks have been found in
sandstone beds, and fragments in which the structure is more
perfectly preserved, are occasionally met with in nodules in the
shale or in the coal itself. These exhibit in transverse section
(fig. 10) a large pith, and the annual rings of growth character-
istic of perennial exogenous plants ; and when cut parallel to
the medullary rays, not only are the cells of the rays distinctly
seen, but the disc-bearing tissue which is present in all known
Coniferce . The discs occur in several parallel rows, unlike the
common conifers of the northern hemisphere, in which they are
always in a single series. They have on this account been
referred to the araucarian type in the woody structure of which
the same arrangement exists. In some specimens, referred to
Dadoxylon , the supposed discs are rather reticulations (fig. 9)
on the wall of the vessel, without the central pore which is a
necessary part of the true disc-bearing tissue. Hooker has
further elucidated the affinities of these fossil conifers by de-
scribing a Trigonocarpon (fig. 11) which was preserved so as
to exhibit structure. He gives satisfactory reasons deduced
from its external appearance as well as its internal structure for
considering it to be rather a coniferous fruit like the drupe of
a Salisburia , than related to palms or cycads as had previously
been supposed. He also points out the probability that the
species of Noeggerathia described as the fronds of ferns, may
have been the foliage of the same trees. So that here, as in
Catamites and Lepidodendron , we seem to be able to construct
from the scattered fragments this Salisburia-like conifer of the
coal measures, finding its trunk in Dadoxylon or Pinites, its
pith in Sternbergia , its foliage in Noeggerathia or Cyclopteris ,
and its fruit in Trigonocarpon !

The small number of genera, and even of species which have
contributed to the formation of the beds of coal, is remarkable ;
and it is probable that the progress of research will even yet
greatly reduce both, but especially the number of species. The

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characters by which the different stems are distinguished are
derived from variations in the arrangement and forms of the
scars produced by the bases of the leaves. In recent tree ferns
these vary in different parts of the same stem, and this may be
expected to have been the case in the coal plants ; and, indeed,
Binney and Hooker have noticed the scars on which have been
founded four species of Sigillaria existing on a single stem.
The paucity of specific and generic forms reminds one of the
extensive native forests of conifers, in the northern hemisphere,
which consist of a very few, sometimes as in the Wellingtonia
groves of only a single species, but the conditions under which
they grew were very different. They covered extensive plains,
growing on a wet, clayey soil. The temperature was not neces-
sarily very high, nor the composition of the air different from
what exists at present. The growth and decay of the forests
were very rapid, and the changes indicated by the succession of
coal, shale, and sandstone more speedily followed each other
than one would at first suppose. Binney has observed an erect
coniferous stem which has deposited around it some thickness of
sandstone, a layer of under clay, a bed of coal, another of shale,
and other successive deposits, all which were formed while it
was a growing tree. Such a series of rapid changes, not pro-
duced by violent volcanic agency, is unknown in the present
day. Both physically and botanically the coal measures pre-
sent many remarkable problems to the naturalist.

EXPLANATION OF PLATE XVI.

Fig.

V

V

1.

2.

Q

O.

if

4.

5.

6.

v

V

V

V

V

1)

7.

8.

9.

10.

11.

12.

13.

Strobilus of Lepidodendron. — Natural size.

Two scales and sporangia of Flemingites. — Natural size.

Single sporangium of ditto, showing the triradiate base. —
Magnified.

Two scales and sporangia of Lepidodendron. — Natural size.

Spores of ditto. — Magnified.

Section of Strobilus of Calamites showing the scales and the
peltate scales, with sporangia. — Magnified.

Strobilus of Calamites. — Natural size.

Scalariform tissue from Lepidodendron. — Magnified.

Reticulations on the woody fibre of JDadoxylon. — Magnified.
Restored stem of Dadoxylon , with its large pith. — (Stembergia.)
Trigonocarpon. — Natural size.

Restored stem of Lepidodendron.

,, ,, Calamites.

299

REVIEWS.

A DICTIONARY OF SCIENCE.*

TWO years ago the first issue of Dr. Brande’s Dictionary was commenced.
The work is now completed, and we only wish we could add complete
also. The general reader who looks at the long list of contributors to the
Dictionary must feel satisfied that all that could he done to render the work
perfect has been effected. When he finds that the various departments
have been presided over by such distinguished authorities as Professor
Owen, Dr. Frankland, Dr. Bindley, and Professor Hirst, he feels confident
that no pains have been spared to meet the wants of those who consult a
scientific dictionary. But when one conversant with the progress of modern
science casts his eye over the pages of Brande’s Dictionary he detects many
objectionable features which a careful revision ought to have obliterated. As
we stated when noticing the first few numbers of this work, we are not at
all satisfied with the manner in which the department of Natural History has
been dealt with. This branch is in point of merit far below all others
except that of microscopy (if we may use the term), which has practically
received no attention whatever. Professor Owen and Mr. Carter Blake are
the writers responsible for this division of the Dictionary, and of the labour
of these gentlemen we regret to be obliged to speak in anything but com-
mendable terms. Whether Professor Owen’s services have been merely
nominal, or whether Mr. Blake’s have been executive, it is not for us to offer
any opinion. But this we must state injustice to our readers, the natural
history sections of the work by no means represent the views of modern
zoologists.

That our opinion is well founded the zoological reader may at once see
for himself, by turning over the leaves of the Dictionary and reading the
definitions of those terms which have reference to general Natural History
and Physiology. Let us see for example what is stated under the heading
of Animal. It is doubtless a very difficult matter to give an unimpeachable
definition of an animal, and as this difficulty is appreciated by the zoologist,
we should have expected nothing more from a writer than a very general
and outlinear expression of the characters which serve to separate the animal
from the plant. The writer of the article, however, does not experience
the obstacles which most physiologists encounter \ his views, we must con-

* “A Dictionary of Science, Literature, and Art.” Edited by W. T.
Brande, D.C.L. F.R.S., and the Rev. G. W. Cox, M.A. In 3 vols. London:
Longmans, 1867.

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POPULAR SCIENCE REVIEW.

fess, are, at all events, clear and decided. It would be pleasant if we
could say as mucb for their accuracy. Professor Owen or Mr. C. Blake, we
know not on whom the paternity of the definition lies, defines the term
u animal ” as follows : — “ The name of the higher division or kingdom of
organised beings distinguished by endowments of sensation and voluntary
motion, superadded to the organic functions which animals possess in
common with plants.” The writer having given this cumbersome and
valueless explanation, proceeds to deal with the objections which may be
urged against it, and to our minds in a very unsatisfactory manner. He
says that it might be thought that certain confervse have the power of
locomotion, and that in some plants a species of irritability is found,
but these faculties in the instances referred to are more imaginary than
real. No one, he says, can mistake the locomotion of a vegetable for that
of an animal organism ; the notion of vegetable sensation results from a
confusion of the terms a irritability ” and u sensation.” Such an ex cathedra
denunciation of the observant and discriminating power of those who
are too cautious to pronounce at once as to the animality or vegetality of
an organism, has a weight of its own, but its force is that of brutum fulmen.
Is it possible that the writer can assert for one moment that the locomotion
of the sponge — whose animal character is undoubted — is superior to that of
the volvox or to that of the diatomacese as pointed out by Schultze P If so
we must give up the argument. Then again, when he talks so flippantly
about confounding sensation with irritability, can he inform us what
exact significance he attaches to either of these terms ? If he can, he will
do us a signal service by giving us the information, and he will confer a
great boon on Modem Physiology. Of what value is zoological definition
when dependent on asserted qualities which he who defines is unable to
offer an intelligible account of? How, for instance, can we distinguish
irritability from sensation when we know that in the case of a decapitated
frog, the so-called property of irritability is to all appearance that of sensa-
tion ? Professor Owen smiles at the untutored physiologist who can dream
of comparing the movement of the sensitive plant with the motion of an
animal, for, says he, u Experiment has shown that the intumescent parts of
the mimosa , in which the irritable property is concentrated, move the leaf
by an extension of cells and not by a contraction of fibres.” This is
plausible enough but it does not stand the test of analysis. How can
Professor Owen suppose his li extension of cells ” to take place without con-
traction P Surely if the movement of a continuous mass displays extension
in one direction it must exhibit contraction in another, unless we suppose —
which we cannot in the case in point— that a general expansion as by heat
occurs. Moreover we would ask Professor Owen to bear in mind that the
so-called contraction of his animal “ fibres ” is attended with a lateral
extension. However, if we yield all these objections to the writer’s dogma
we still have the important fact that in the movements of the Amoeba,
there is no contraction of fibres , for the simple reason that there are no
fibres to contract. This one fact is quite sufficient to refute the writer’s
argument. The other statements in the article in question are certainly
opposed to our belief. We have yet to learn that every animal is provided
with i( an internal cavity ” for digestion, as we know that certain species

REVIEWS.

301

extemporise a stomach, by, as it were, pushing their food into the substance
of their bodies. We were not aware either, that all plants exhaled
oxygen, or that all animals gave off carbonic acid ; but it is well even in
1867 to have these hitherto debateable points clearly established. We must,
however, raise our voice against the classification which places the Desmidice
and Infusoria together as the lowest forms of animal life, and which ranges
the former under the sub -kingdom Protozoa.

Passing to another branch of the subject we find the Teredo described as
“ a worm which enters wood in salt water, and there expands until it has
attained the size of a finger.” It is true that this information is given
under the head of Boring-worm, but then as the paragraph contains no
allusion to the Mollusca, and as the definition of the Teredo in another
volume is never referred to, the casual reader of course carries away the
valuable instruction that the Teredo is an annulose creature — a very common
mistake, and one which a dictionary like Dr. Brande’s should lose no
opportunity of correcting. The cirripeds are defined to be “ a class of fixed
homogangliate animals,” &c. Now what is the knowledge thus conveyed P the
term homogangliate is seldom used now-a-days, and very few people under-
stand that it refers to a symmetrical nervous system ; but even assuming this
knowledge on their part, how erroneous an idea is conveyed of the history
of the Cirripedia, by the statement that they are fixed animals. It is idle to
say in excuse that in other paragraphs the fact is conveyed that in their early
life these creatures are free. The definitions should have been carefully
framed, and not given piece-meal, as disjecta membra , scattered over the
3,000 pages of three large volumes. The ' Ciliograda — a bad term, we admit — is
certainly not properly said to be a 11 tribe of Acalephans.” By the term Acalephce
the reader understands the functionally independent reproductive bodies of
certain of the Hydrozoa, whereas if we mistake not, researches, not of a very
recent character either, have determined the affinities of the Beroe and a Cy-
dippe to be with the Actinozoa. On the same page on which this paragraph
appears we notice one termed ciliary , in which to our utter astonishment we
see no allusion whatever to the muscle of the name ; the old word ligament
is used, and its attachments are very incorrectly and imperfectly given.
Why, we would ask also, is the class JEchinodermata said to be a class of Radiate
animals ? Surely enough has been written upon the structure and develop-
ment of these interesting animals to show that they should be removed
from the Hydra and Actinia, with which they have no more structure in
common than a man has with cuttle fish ! Numerous similar examples of
what we have alleged could be pointed out, but the few above given are
sufficient, ex uno disce omnes. The orthography, too, is frequently very defec-
tive, and shows carelessness on the part of the scientific 11 reader ;” of this
we have instances, such as saccode for sarcode, Zapadidse for Lepadidce , Pali-
nunus for Palinurus.

As to the manner in which microscopy has been dealt with, we can only
say that little or no attention has been given to the subject. There is an
article of about two or three pages upon the general principles of the
microscope, but it is obvious that the subject could not have been properly
treated in so short a space.

Elsewhere, we find one or two references to pieces of microscopic

302

POPULAR SCIENCE REVIEW.

apparatus, but the microscopist cannot fail to perceive that his interests
have not received any consideration from the editors of the Dictionary. In
the conduct of the other departments, we think the gentlemen employed to
bring the dictionary up to £he standard of modern science, have discharged
their several duties with intelligence and discrimination. The work is a
very valuable one in all respects but those to which we have drawn at-
tention, but in these it is certainly u behind the time,” and we cannot but
regret that such a circumstance should exist to mar the usefulness of so
admirably conceived a plan.

ICELAND.*

THIS work is the account of a tour made in exploration of the north-west
peninsula of Iceland and the Yatna Jokul, and it would doubtless
interest those of our readers who are of an exploring turn and are at a loss
for a country in which adventure may be combined with a sufficient
amount of danger to make it piquant and attractive. One of the author’s
objects was to investigate the ornithology of the island, and he has to a
certain extent carried it out successfully. The bulk of the volume is occupied
by the details of the trip. This is usual in books of travel, but for what
earthly reason it is so, we cannot divine. We doubt if any one ever cares
to wade through this part of a book. It is very tedious to read on page after
page through a volume, and learn nothing except the number of eggs eaten
by the author at his breakfast, or the difficulties which attended his repose.
Mr. Shepherd, however, evidently thinks otherwise, and though one of his
aims related to scientific investigation, the greater part of his book is filled
with those u notes from my diary” which are so distressingly dreary to the
— well we shall only say — reviewer. Passing by this portion of the author's
lucubrations, we find toward the conclusion of the volume, a few details of
scientific interest which we think may be profitably “ crystallised out”
from the rest of the letter-press. The following description of the sulphur-
mountains is of interest : u These large hills are a very wonderful sight.
They are of various colours, a variety of mixtures of red and yellow. From
their sides are emitted numerous jets of steam, and masses of bright yellow
sulphur are strewed all round them. At the foot on the eastern side are
the mud-geysers — huge caldrons of blue mud in different states of solution.
Some bubble and spurt like filthy water j others are so gross that they can
scarcely heave the massive bubbles to the surface. They are the centres of
broken and dilapidated cones, raised by their own sputterings. The highest
part of their cones, which was that part towards the mountains, was about
three feet. They are however continually changing in shape ; and I ob-
served that these portions of the cones themselves was (sic) different from
what they were when I visited them in 1861. All around the soil was

* The “ North-West Peninsula of Iceland.” By C. W. Shepherd, M.A.
F.Z.S. London : Longmans, 1867.

REVIEWS.

303

very treacherous, consisting- of hot mud with a covering of sulphur about an
inch in thickness, which in most places was about sufficient to bear a man’s
weight. When this crust was broken, steam issued forth, strongly impreg-
nated with sulphur. The clouds of steam, the roaring, the spluttering, and
the splashing of these loathsome pits, the sickening smell and the desolate
■country had somewhat of an awe-inspiring effect.” Mr. Shepherd gives
some instructive details of the habits of the Icelandic birds, and he has given
some happy sketches of Icelandic scenery, which have been chromo-litho-
graphed in Hanhart’s best style.

THE ELECTRIC TELEGRAPH.*

THE excellent and well-known treatise of Lardncr has been carefully
revised and rewritten in accordance with the advance made of late
years in the department of electrical physics. The task of editor was en-
trusted to Mr. Edward Bright, and the publisher may congratulate himself
on the selection. The book is in most respects a good, sound, intelligible,
practical treatise on the electric telegraph. It deals with the elementary
principles on which the application of electricity to telegraphic purposes is
based, the modifications of the original apparatus employed in various
■countries, the different forms of conducting cable, and finally of the uses —
commercial, social, and political — to which the electric telegraph has been
applied. There is one feature however, against which we must raise our
voice : Electricity is described in the language of the popular lecturer as

a 11 subtle fluid.” This is extremely objectionable, and the more so as the
editor is fully aware that the modern view of the force is opposed to such
a mode of expression. Mr. Bright urges that the term fluid is the most
convenient for the purpose of explaining electrical phenomena. In this
we totally differ from him. In the first place the term so applied is erro-
neous, and in the second, the word wave would answer every purpose which
is served by fluid. For the merely practical electrician, there may be no
harm in employing the word fluid, but it must be remembered that Dr.
Lardner’s work as the chief popular treatise on the telegraph, goes into our
schools and families, and is thus calculated to do a certain amount of mischief.
Mr. Bright may not be familiar with the history of other sciences, but if he
be, he must know how injurious to the progress of knowledge it is to
hamper a branch of science with a term implying an hypothesis which has
not one tittle of evidence to support it Such expressions as “ vital force ” and
“electric fluid,” and such like, are stumbling-blocks to the progressive student.
We have little doubt that had it not been for the adoption of such techni-
calities as electric-fluid, tonicity, and irritability, the action of the muscles

* The “Electric Telegraph.” By Dr. Lardner. A new edition revised
and rewritten. By E. B. Bright, F.R.A.S. Secretary of the British and
Irish Magnetic Telegraph Company. London : James "Walton, 18G7.

VOL. VI. — NO. XXIV. Z

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POPULAR SCIENCE REVIEW.

in animals would long since have been admitted to be due to electric con-
ditions, but scientific progress has been prevented by these barbarisms of
hypotheses.

The descriptive portion of the book is, as might have been expected, re-
markably clear and correct, and is full of anecdotal matter of an interesting
and amusing character, so that pleasure and profit may be gained in its
perusal. We would refer especially to the accounts given of the modem
appliances by which the telegram is electrically printed at the u receiving
station.” No form of apparatus is omitted, and those varieties described are
carried home to the reader’s mind by the assistance of the admirable woodcuts
which accompany the text. The chapter on the application of the telegraph
in railway signalling, should be read by all who wish to know how it is
that trains may follow each other at full speed, and at short intervals of
time without the least danger of accident by collision. Of the immense
advantage of the telegraph in railway operations, the following facts recorded
in the present volume will amply demonstrate. “ On New Year’s day 1850
a catastrophe which it is fearful to contemplate, was averted by the aid of
the telegraph. A collision had occurred to an empty train at Gravesend; and
the driver having leaped from his engine, this latter started at full speed for
London. Notice was immediately given by telegraph to London and
other stations, and while the line was kept clear, an engine and other ar-
rangements were prepared as a buttress to receive the runaway. The
superintendent of the railway also started down the line on an engine ; and
on passing the runaway he reversed his engine and had it transferred at the
next crossing to the up-line so as to be in the rear of the fugitive ; he then
started in chase, and on overtaking the other he ran into it at speed, and the
driver of his engine took possession of the fugitive, and all danger was at an
end. Twelve stations were passed in safety ; it passed W oolwich at fifteen
miles an hour ; it was within a couple of miles of London before it was
arrested; had its approach been unknown the mere money value of the
damage it would have caused might have equalled the cost of the whole
line of telegraphs. They have then . paid, or in a large part paid for, their
erection.”

Dr. Lardner’s book is full of other similar facts, illustrating the benefits
which the telegraph has conferred on humanity at large. The de-
scription of the telegraph from the House of Commons to the Opera, shows
what curious services electricity is made to perform. The progress of busi-
ness in parliament is regularly reported in the Lobby. So that “ Young
England has only to lounge out between the acts to know if Disraeli or
Lord John Russell is up, and whether he may sit out the piece or hasten
down to Westminster.” We have said enough to show the highly interest-
ing character of Dr. Lardner’s volume, and we now therefore leave it, trust-
ing that our readers will take it up and judge of it for themselves.

REVIEWS.

305

HOSPITALS.*

THOUGH this work hardly comes within the scope of the Popular Science
Reviewer, we venture to call attention to it because of its high intrinsic
merits, and from the circumstance that many of our readers are interested in
hospitals or other charitable institutions, and will, we believe, be glad to
know upon what general sanitary principles, hospitals and such like public
buildings should be cultivated. All the information which can be desired
on these points is to be found in the fine volume before us. Dr. Oppert not
only goes into the minutest questions of hygiene, as relating to hospitals,
but he discusses the points on which he dwells with candour and earnestness,
and so far as we can discern, he leaves no views unnoticed, no matter
whether they be opposed to his own independently formed opinions or not.
It is impossible for us to attempt even the briefest analysis of his labours,
but we may state the nature of the division which he has adopted for his
subject. We may say that his book is divided into three portions ; in the
first the principles on which hospitals should be constructed are minutely
detailed, then follow an expression of opinion as to the Administration of
hospitals, and finally we are given a succinct account of the hospitals of the
United Kingdom and of the Continent. There is only one point which we
desire to bring under our readers’ notice, and that is the question of venti-
lation. Dr. Oppert explains fully the different forms of natural and artificial
ventilation which are used in European Hospitals, and then proceeds to
offer his own opinions as to the mode to be preferred. He advocates neither
the strictly natural nor the artificial means, but considers that the juste
milieu is the best. His remarks are of much importance, for what he asserts
of hospitals must within certain limits be true of private dwellings. The
conclusions at which Dr. Oppert arrives are thus formulated. (1.) Venti-
lation by doors and windows cannot at any time be dispensed with in
hospitals. (2.) Hospitals may rely on ventilation by windows and doors
in summer time, but if an artificial system is to be instituted, none but that
by forcing in the air is efficient in summer. (3.) In winter time some of
the artificial systems may operate with advantage, and cannot be dispensed
with in clinical wards or consumption or fever hospitals during the cold
season. (4.) No channels for withdrawing air should be formed, unless a
continuous draught is caused in them. A ventilating fire is a more powerful
agent than a hot cistern, and for the lower floors it is better to have the
fire in the basement. If there is a second or third the fire should be as near
them as possible, and not in the basement. (5.) Where hot-water pipes or
stoves are used for warming, the outer air may pass over or through them
into the wards by channels communicating with the atmosphere ; where there
are only chimneys, they may be surrounded by an air-chamber to the same
purpose. Such an arrangement is indispensable with the new improved fire
grates. (6.) Open chimney fires are capital aids to ventilation, and can be
combined with every other system. (7.) The construction of the windows

* u Hospitals, Infirmaries, and Dispensaries : their Construction, Interior
Arrangement, and Management.” By F. Oppert, M.D. London : Churchill,
1867.

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POPULAR SCIENCE REVIEW.

is most important; and should be considered well whenever a new hospital
is erected. It is not necessary that they should be on a uniform plan. No
large entrance door should be without a large louvre above. (8.) Two zinc
plates or tablets should be placed in the upper part of or above some of the
windows; in order to break the air current, the inner plate sliding over the
other, so that the apertures may be closed. The nurse to keep a rod for
this purpose.

THE SCIENCE OF A CYCLONE.*

FROM year to year we receive abundant testimony of the activity with
which Indian scientific workers carry on their researches, and the
latest result in this direction which we have to record is embodied in the
valuable volume which we have just received from the Bengal Government.
This work is a veritable chef d'oeuwe of scientific acumen; earnest labour,
persevering energy, and skilful discrimination. It would be creditable to
any country, but it is doubly creditable to a country wherein civilisation is as
yet incomplete and where climatal conditions are so eminently unfavourable
to intellectual pursuits. Indeed we should be glad to find so excellent and
elaborate an account of any important meteorological phenomenon occurring
in Great Britain. Some of our readers may remember what a dreadful catas-
trophe the cyclone described in this report was. The storm raised a wave
which poured over the country for miles, breaking down embankments,
sweeping away whole villages, and with them their inhabitants. It was
one of the most remarkable natural phenomena on record. Destructive of
population and property, to an almost inconceivable extent, it yet might
have been anticipated had meteorology been more carefully studied. As it
was it produced a loss of life which is estimated below the mark at 48,685
souls.

To investigate the phenomena which preceded, accompanied and followed
this cyclone is the task which the editors of the admirable work before us have
set themselves to perform and which they have so successfully achieved. It
is quite astounding to see the mass of evidence which has been collected from
all quarters reached by the inundating wave, the more so, as the phenomenon
was unexpected and was of so terrific a character that in many instances the
self-registering instruments were destroyed and the meteorologists fled in
horror from buildings which threatened every moment to bury them in
their ruins. Numerous maps, charts, plans, and carefully compiled schedules
accompany the letter-press and give adequate support to the editors’ conclu-
sions. For these latter we must refer the reader to the book itself, but the
u suggestions ” which are offered, are we think of sufficient interest for
quotation. These are to the effect that the cyclones in the bay are pre-
ceded by a strong damp stormy wind from south-west or west-south- west to

* Report on the Calcutta Cyclone of the 5th of October 1804, by Lieut.-
Col. J. E. Gastrell and Henry Blanford, A.R.S.M. Calcutta Military Orphan
Press, I8C6.

REVIEWS.

307

tlie south-west of their origin. It is found that the barometer ranges lower
than usual on the part of the hay in which they originate. This depression
takes place during a slight general fall of the barometer over the bay, such
as occurs normally at intervals of a few days to a fortnight, at all seasons of
the year. The formation of the cyclonic vortex appears to be preceded by a
general recurvature of the southerly current around the place of low baro-
meter. When the vortex forms the barometer falls still lower over the
vortex and continues to fall while the cyclone gathers strength. The re-
curved south-westerly current being the chief feeder of the cyclone, and the
vortex being formed more or less towards its western limit, the weather to
the east and north-east of a cyclone is more stormy than that to the west and
north-west of it. In and around the cyclonic vortex there is a strong in-
draught of the wind-currents so that their direction is spiral, not circular,
but more nearly circular within ten or fifteen miles of the centre than at
greater distances from it. Finally the editors say that “the cyclones do not
in all cases (perhaps in any P) move forward steadily on their track, but one
vortex may break up while another is forming at some distance in advance.’’
The duration of a central calm cannot therefore (even if its diameter be
known) be taken as a measure of the rate of progress of the storm (the suc-
cessive vortices being considered as one storm).

It will be seen by the above suggestion-conclusions, if we may use such a
term, what good work Indian meteorologists have done. Let it be an ex-
ample for those who so energetically decry the Fitzroy weather signals, and
decline to give us even substantial facts in their stead. Let some English
meteorologists follow in the footsteps of their Indian brethren and give us
on the subject of “Storm-signals” a treatise of which we may say, as we
do honestly affirm of the one before us, that it is a model meteorological
monograph.

POPULAR ASTRONOMY*

PERHAPS the reader may say we are overdosed with lectures on Astro-
nomy. There appears too, to be some truth in the remark, but though of
late years the works on this branch of science have been very numerous,
some of them have been works whose many technicalities and references to
the higher mathematics placed them at once beyond the comprehension of
the amateur. It is, however, the special feature of all Dr. Lardner’s books
that they address themselves to the general public/and we may observe also
that while they are tolerably accurate in point of fact they are written in a
language at once terse and untechnical, and which is easily intelligible to
those whose mathematical knowledge is of the usual elementary character.
It happens, however, that a good deal of advance has been made in the
several branches of science which Dr. Lardner endeavoured to popularise

* Handbook of Astronomy, by Dionysius Lardner, D.C.L., 3rd edition.
Edited by Edwin Dunkin, F.R.A.S. London: James Walton, 1867.

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POPULAR SCIENCE REVIEW.

since the period at which his various essays were published ; Mr. Walton
has therefore been engaged in bringing Dr. Lardner’s works up to the present
condition of scientific knowledge. In one of our late numbers we called
attention to a new edition of Dr. Lardner’s Natural Philosophy, and we have
now the pleasure of bringing another of Dr. Lardner’s books under our readers’
notice. The work before us, even in its first edition, was an excellent general
treatise, and the present edition is as fully in accordance with modem dis-
covery as its predecessor was with the science of its time. Those who are
acquainted with the second edition will not find many novelties in the
present work. There are some new features, however, which are of interest
and importance. One of the chief points in which this differs from the second
edition relates to the horizontal parallax of the sun, which in conformity
with the opinions of the leading astronomers has been increased from 8"-5776
to an alteration which necessarily involved other important numerical

corrections. Among other points referred to for the first time in this volume
are notices of the discovery of thirty-three minor planets. The illustrations
are of an excellent character, the woodcuts intercalated with the text, being
clearly executed and simple, and the plates, especially those of the comets
and nebulae, being carefully and skilfully executed. The work commends
itself especially to junior students, schools and families, and deserves an
extensive circulation.

Natural History Transactions of Northumberland and Durham , Yol. I.
Part II. Dodsworth, Newcastle-on-Tyne. — This the second part of this
well-conducted publication is full of important contributions and contains a
series of illustrations which would do credit to a London publisher. All the
articles deserve to be read, but there is one which is worthy of careful
attention, that “On an Ancient British Burial at Ilderton, Northumberland,
with notes on the Skull.” In this the writers, the Bev. W. Greenwell and
Dr. Embleton, give a minute account of the interesting archaeological
district of old Berwick, and of an ancient British skull found therein. The
drawing of this latter, which accompanies the paper, is certainly a master-
piece of artistic skill. We doubt whether we have ever seen a better
anatomical illustration than this. The zygomatic processes stand out with
an almost stereoscopic effect. The following description of this skull shows
it to have belonged to a man of about forty-five years of age, and who must
have possessed (so far as we can judge) a more than average degree of
intelligence. The skull is robust, well-arched and symmetrical, its supra-
ciliary arches are very prominent, and its external angular processes well
developed. The forehead slightly recedes. The occipito-parietal region is
large and rounded. The mouth is rather large and well-formed, and con-
tained a full set of fine teeth. The lower jaw has a strong square and some-
what projecting chin, the angle is not far from being a right angle, and the
distance across from angle to angle is considerable. The frontal sinuses
appear to join together and form a projection over the root of the nose. The
temporal fossae are wide and large. The coronal saggital and lambdoidal
sutures are partially obliterated. — The other papers in this number are full
of interest.

SCIENTIFIC SUMMARY.

ASTRONOMY.

IN our summary for January, it was recorded that Professor Adams liad
seen reason to doubt the correctness of the period assigned by Professor
Newton to the November meteor-ring. The rigid mathematical scrutiny of
the nodal motion due to the actions of Venus, Jupiter, and the Earth — the
planets which would be the principal perturbers of the meteoric Orbit on
Newton’s hypothesis — has resulted in showing that 354-6 days is not the
true period of the orbit. In like manner a period of 377 days — another
view suggested by Newton — must be abandoned. Either theory gives to the
node an annual motion of about 2F', whereas to account for the observed
change in the epoch at which the November shower occurs, a motion of
52//*4 is required.

It remained to calculate the motion of the node when a period of 33*25
years is selected — that being the only other period, besides those considered,
which fairly accounts for the interval observed to separate successive
recurrences of brilliant meteoric displays. This period, which gives (by
Kepler’s law) an elliptic orbit, having a major axis 20*7 times as great as
the earth’s distance from the sun, presents many difficulties. The formulae
adapted to the nearly circular planetary orbits are here inapplicable. Adams
applied the method given by Gauss in his “ Determinatio Attractionis, &c.”
In this method the long ellipse is broken up into small parts, and the
perturbing effects of the planets on the motion of a meteor in each part is
considered, the change in the node as the meteors move over each section
being separately examined. The calculation is very laborious, though
Professor Adams simplified the work to some extent by introducing several
ingenious modifications. He found that during a period of 33*25 years the
longitude of the node is increased 20' by the action of Jupiter, nearly 7' by
the action of Saturn, and about 1' by that of Uranus. The other planets
produce no appreciable perturbations. Thus the observed increase of
longitude is about 28' in 33*25 years, or 50"*2 in one year. We have
already stated that the observed motion of the node is 52//*4. The accordance
is close enough to leave no doubt that the true period of the November
meteors is 33*25 years.

This result very largely enhances the interest with which the phenomenon
of periodic November displays must be viewed. On Newton’s hypothesis
one could understand the recurrence of brilliant showers during two or three
successive years ; since the earth was assumed to pass for two or three years
in succession through parts of the ring not very far separated from each other.
But with meteors travelling in an elongated ellipse, extending beyond the

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orbit of Uranus, the case is far different. The part of the meteoric ring-
traversed at one passage has travelled away more than a 100,000,000 of
miles, when the earth next crosses the stream. Therefore to understand the
recurrence of star-showers during two successive years only — and we have
well authenticated instances of showers occurring three or four years suc-
cessively— one must conceive a stream of meteors extending more than a
100 miles in length.

This being the case it is the more remarkable to find the important
November shooting-star displays, which have continued for at least 600
years, associated with a telescopic comet which has escaped discovery until
quite recently. Yet it results from Adams’ discovery that the orbit of the
November shooting-stars accords in the most remarkable manner with the
orbit of Comet I, 1866 — a minute tailless comet discovered in January of
that year by M. Tempel. Professor Adams’ elements of the November
meteors are here compared with Dr. Oppolzer’s elements of Tempers

comet : —

Period .

Mean distance
Eccentricity .
Perihelion distance

November Meteors. Comet 1, 18G6

33-25 (assumed) 33-18
10-3402 10-3248

0-9047 0-9054

0-9855 0-9765

o / o /

Inclination 16 46 17 18

Longitude of node . . . 51 28 51 26

Distance of Perihelion from node . 6 51 9 2

Direction of motion Petrograde. Retrograde.

This evidence following on Schiaparelli’s proof of the close accordance
between the orbits of the August meteors, and that of Comet II, 1862, seems-
all but decisive. The association of comets — and especially of comets of
eccentric orbit — with shooting stars, is certainly one of the last that would
have occurred even to the most speculative astronomer, yet it is now esta-
blished on a foundation that will not'be readily shaken.

Mr. Cleveland Abbe has discussed in an interesting paper the important
question of the distribution of nebulae in space. He exhibits in a table the
number of irresolvable nebulae contained in each space of the heavens ex-
tending 10 in declination and half an hour in right ascension. The result is-
confirmatory in some respects of that deduced by Sir John Herschel from
the tabulation of a smaller number of nebulae of all classes. There is a de-
cided paucity of nebulae in the region traversed by the Milky Way and its-
outliers, and an equally marked aggregation towards the poles of the
Galactic circle. Mr. Abbe therefore follows Herschel in the opinion that the
irresolvable nebulae are independent universes similar to the Milky Way in.
character, and that the magellanic clouds are members of this 11 system of
universes,” which happen to lie somewhat nearer than the others to our own
universe, the Galaxy. Without pronouncing a decided opinion against these
views we must point out that the method of tabulation adopted by Mr. Abbe
is not very well adapted to exhibit any tendency there may exist to sys-
tematic distribution. The method described in Sir John Herschel’s Cape
observations seems better fitted for this purpose, and perhaps if applied tor

SCIENTIFIC SUMMARY.

31 1

Mr. Abbe’s materials might lead to somewhat different results. The subject
is one which, in the present stage of astronomical progress, deserves to be
most carefully studied.

W e do not hear that any views have been obtained of Mars during the
recent opposition which add much to our knowledge of the features of this
planet. At a late meeting of the Astronomical Society, Mr. Browning
exhibited a series of .views which he had obtained with Mr. Barnes’ 8§-inch
silvered glass reflector. Nearly thirty sketches were made. These agree
well with those made by Mr. Be la Hue with his 13-inch metal speculum,
and fairly with the exquisite drawings b}r Mr. Dawes. We have seen
series of views, by the way, equalling the last named in fullness of detail,
and in consistency.

Mr. Huggins has renewed his observations on the spectrum of Mars.
Using a direct vision spectroscope, he found lines in the spectrum which he
was enabled to assign to the atmosphere of Mars ; since, while resembling
lines produced by our own atmosphere in the solar spectrum when the sun
is low — the situation of Mars precluded the possibility of their being ascribed
to the earth’s atmosphere. He ascribes the colour of Mars to the nature of
the soil — a view confirmed by the definite outlines of regions tinted with
the peculiar ochreish colour characterising Mars, and by the circumstance
that the polar regions appear white, though they are seen through a greater
depth of atmosphere than the equatorial regions. The views of Dr. Zollner,
quoted with favour by Mr. Huggins, do not appear quite so well worthy of
confidence as those resulting from Mr. Huggins’ own observations. The
opinion, for instance, that the increased light near the edge of the disc is
due to the existence of hills having a slope of 76° (as great as that of the
Peter Botte Mountain) and distributed all over the surface of Mars, appears
to us bizarre in the extreme.

Mr. Dawes appends to a valuable paper on the micrometrical measurement
of double stars, a series of observations most instructive and interesting to
the telescopist. Our space will not permit us to enter at length into the
discussion of these, but some results are too remarkable to be passed over
without comment. The effects produced by changing the figure of a tele-
scope’s aperture have been carefully studied by Mr. Dawes. A round disc
placed centrally before the aperture increases the separating power of a
telescope, but increases both the number and the brightness of the rings
round the brighter stars. Thus the smaller components of a brighter star
may be hidden by one or other of the rings. And in this connection another
observation of Mr. Dawes is noteworthy ; viz. that a larger aperture may
fail (in appearance) to separate stars clearly divided by a smaller aperture,
owing to the circumstance, that within the larger instrument, one of the
rings of light round a star may happen to pass directly through the com-
panion. A perforated whole aperture may frequently be employed with
advantage. It has the effect of considerably diminishing the star discs
owing to the loss of brilliancy, while the full effect of the whole aperture in
reducing the diameter of the disc is also preserved. A triangular aperture,
produces an hexagonal star-disc, with bright rays from each side ; these
rays have an inconvenient effect, sometimes obliterating or distorting a
small companion. A hexagonal aperture has the power of effectually cor-

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rupting the tendency sometimes observed in telescopic star-disc to become
triangular. An interesting discussion arose at a late meeting at the Astro-
nomical Society, on this singular tendency. It has been observed by Mr.
Dawes to occur only when the wind is from the east. The Astronomer Royal
ascribed it to the effects of an easterly wind on the health, an opinion, how-
ever, in which many experienced observers do not coincide with Mr. Airy.
The fact that a particular aperture corrects the tendency seems, also,
decisive on this point. A kindred phenomenon, the circumstance that a
shorter focus is required for objects near the horizon or seen through a haze,
was discussed in connection with the other. Here again the Astronomer
Royal held an opinion not accepted by several distinguished observers. He
ascribed the phenomenon to the difference between direct and skew vision.
We believe that Mr. Dawes never uses skew vision, his observing chair
being ingeniously contrived so as to give in all cases direct (and com-
fortable) vision. The fact that a short focal length is required for parts of
the sun near the limb, and a long focal length for the moon, seems to show
that the question is merely one of distinctness of objects. In proof of
which we may quote Mr. Dawes’ observation, that young observers, in their
anxiety to see perfectly well while setting the focus, use nearly always too
short a focal length. Here our comment on Mr. Dawes’ valuable paper
must cease ; but we commend the whole of it to the most careful study
of the telescopic observer.

An error in M. Leverrier’s calculation of the sun’s distance from the
earth’s parallactic inequality has been detected by Mr. Stone. The result
is to reduce the estimate by 400,000 miles, or to give the value already
obtained by M. Hansen. Mr. Stone has himself obtained a new estimate.
His calculation, founded on the observation of Mars/ gave, as our readers are
aware, 8" ^4, for the sun’s equatorial horizontal parallax — the same value,
nearly, as had resulted from Leverrier’s faulty calculation. Mr. Stone’s
examination of Greenwich lunar observations, bearing on the lunar pa-
rallactic inequality, gives a parallax of 8"‘85. The values now being obtained
by different astronomers cluster closely round M. Hansen’s value 8/A916.

Mr. Stone has examined the question of the sun’s motion in space, with
results confirmatory of those already obtained. But he considers that the
sun’s motion is not so great as that of most stars.

He has also examined the interesting question of possible changes in the
earth’s axis of rotation, accruing from the action of the tides. He finds no
evidence pointing to the possibility of appreciable change, even in long
intervals of time.

The eclipse which occurred on the morning of March 6, was observed by
several astronomers. One observer noticed that the penumbra of a spot on
the sun appeared to grow indistinct as the moon’s limb approached it, an
observation suggesting the existence of a lunar atmosphere of small extent.
Mr. Browning and Mr. Lassell noticed that a snow storm occurred in the
upper regions of air during the progress of the eclipse. We find nothing
else worthy of special record.

From India we hear that the November meteors were well seen at
Kishnagur, fifty miles north of Calcutta. Places from which the shower
is now known to have been seen range over a full fourth of the earth’s
surface.

SCIENTIFIC SUMMARY.

313

We hear, also, of a meteor shower observed on October 25, 1866, at noon
in West Australia.

On August 21, Jupiter will appear for an hour and three quarters without
visible satellites. The occulations, eclipses, and transits of the several
satellites will doubtless be watched with interest by the telescopist.

BOTANY.

The affinities of Erica carnea. — Dr. H. F. Hance has contributed a paper
on this subject to the Journal of Botany , in which he gives some very
useful comparisons of E. carnea with the allied European species. The
specimen examined by him had been collected in Devon, and had lain
unnoticed for several years in his herbarium. It seems to be most closely
related to E. Mediterranean so closely, indeed, that Mr. Bentham unites the
two. This view is, however, opposed by Mr. H. C. Watson, the accomplished
editor of the Cybele Britannica , who explains what he considers an error, by
supposing that Mr. Bentham must have confined his examination to herba-
rium specimens, “ which are much alike, although in a living state the
whole habit of growth of the two species as well as their climatal require-
ments are widely dissimilar.” Nyman gives the following as the distribution
of the species : — E. carnea : Switzerland, Austria, Germany, Italy, Dalmatia,
Croatia, Hungary, Transylvania, and Greece. E. Mediterranea : Inland
France, Spain, France, and Portugal. Dr. Hance seems to have given the
matter some attention, and his conclusion is as follows : — <l On comparing
the Devonshire plant with the Irish one, and with a Tyrolese specimen from
Mr. Baker, and a Savoy one collected by Huguenin, of E. carnea , it is
evident that it agrees rather with the latter ; — the corolla being constricted
at the throat, the anthers entirely exserted — and the leaves, some of which
are conspicuously keeled, whilst others are as evidently furrowed beneath —
having the decurrent line from their base distinctly prolonged to the second
whorl beneath them. I fear, however, that implicit reliance cannot be
placed on the two last characters, which Professor Babington gives as
diagnostic, for in E. carnea the median keel of the leaves, though apparently
always distinct at the base, sometimes gradually merges into a furrow about
halfway up, and the ridge also occasionally ceases at the nearest inferior verticil.
Nevertheless, the shorter, wider, open-mouthed corolla, and semi-included
anthers of the Irish species give the flowers so very distinct an appearance,
that I do not think the two could well be confounded.” — Vide the Journal of
Botany , May.

A Hybrid Palm of a very remarkable character has been produced by M.
Denis of Hyeres. He obtained it by impregnating the ovules of Chcemerops
humilis with the pollen of Phoenix dactylifera. As might have been expected,
the hybrid is intermedial in character between the two parents; but the
plants produced from its seeds resemble the male plant more decidedly than
the female.

The St. Mary’s Botanical Lectureship. — We have much pleasure in stating
that Dr. Trimen was lately unanimously elected to this office. No more

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fitting candidate could have been chosen. In these pages we have fre-
quently had to chronicle Dr. Trimen’s discoveries, and we trust that his new
appointment will only add vigour to his well-known spirit of botanical
inquiry.

The Vascular System of the Araliacice , which has hitherto received hardly
any attention from physiological botanists, forms the subject of a fine me-
moir which has been presented to the French Academy by M. Trecul, who
states that its vessels are most closely allied to those of the umbelliferm.
The proper juice, or fluid, of the vessel appears to be oleo-resinous in some
of the species, and gummy in others, whilst in Panax Lessonii this liquid
is oleo-resinous in the fruit, and is gummy in the stem. The canals
which contain the juice-proper are distinguished from the others by the
absence of any particular membrane, and by the presence of a boundary
envelope of cells, whose constituents, though not always differing in form
from their neighbours, may be at once distinguished by their contents. In
the roots M. Trecul has only met these canals in the bark. As in the Umbel-
liferae, those of the periphery are often narrower than the others, and are
situate more or less near the suberous layer, and unite with each other by
oblique or horizontal branches. The details of M. Trecul’s paper are too
numerous for further notice. Our readers should consult the original com-
munication for themselves. — Vide Comptes-Rendus, May 6th.

The Hybridization of Plants. — A paper on this interesting operation was
lately presented to the Botanical Society of Edinburgh by Mr. J. Anderson-
Henry. The author of the paper commenced his experiments nearly thirty
years ago, being fully convinced of the accuracy of M. Lamarck’s views.
Among other interesting facts adduced in this paper is the following,
relative to the intercrossing of the species of different countries. We give the
author’s own account : — u I may here notice a fact I have found of almost
universal occurrence among my experiments, that when I had to cross an
American with an Asiatic species, it took much more kindly than crossing
either of these, especially the former, with European species ; and, lest I
shall not have another opportunity of recurring to this subject, I may here
observe also the decided preference of plants of the southern hemisphere
to intercross among themselves, however remote their original homes may
be — e.g. I found how much easier it was to cross Australian and New
Zealand plants with their allies of South America, than with European or
kindred species in the northern hemisphere. I have also observed that true
American species have greater aversion to cross with European than with
Asiatic species, and that Asiatic species have no less aversion to intermix
with European kinds. There is only one instance, I remember, of effecting
a successful cross between an Asiatic and a European species, and that was
in crossing a small species of Rhododendron with yellow ITelianthemum-
like flowers, being a form of Rhododendron lepidotum called R. elceagnoides ,
of the Sikkim ranges, with R. ferrugineum, a European kind. Of this cross
I raised two plants ; one died, and I kept the other for years ; it flowered
with me, the blooms being dirty red, splashed with a pale yellow tint. It
was an odd-looking thing, and I afterwards sent it to Kew as a botanical
curiosity.” *

Strength of the Stalks of Cet'eals not dependent on Silica. — M. Velter has

SCIENTIFIC SUMMARY.

315

published the results of a series of analyses and experiments, which demon-
strated beyond all question that the weakness of the stalks of corn — so
fertile a source of injury to the farmer — is not due to the absence of silica.
This is merely, however, a corroboration of the conclusion already arrived
at by M. Isidore Pierre. But M. Velter’s inquiries have been pushed
further. He has found not only that a supply of silicate of potash to the
growing plant renders the stem less able to resist the effects of the wind,
but that the cause of weakness is a want of general nutrition, an absence of
the proper quantities and proportions of all the elements which enter into
the composition of the stem. His paper contains several interesting tables,
and it concludes as follows : — If corn is blown down, it is not because it
wants silica — which, by the way, is always present in the free state — but
because owing to want of air or light, or want of development of the woody
matter, the lower part of the stem has not undergone its proper develop-
ment. The base of the stem is etiolate and incapable of supporting the ear.
Giving it light, and sowing the corn in trenches, are the best means of
preventing breakage.

The Corpuscles found in diseased Silk-worms. — A discussion has taken place in
Paris relative to the nature of these bodies and to their mode of reproduction.
MM. Pasteur and Bechamp contend that they are reproduced hj fission and
that they have seen the several stages of .the phenomena. M. Balbiani,
however, disputes this view and gives the following objections to M.
Pasteur’s observations : (1) The bodies examined by M. Pasteur may have
been extraneous, and not related to the so-called pebrine corpuscles. (2)
They may have been abnormal bodies produced by the union of two or more
ordinary corpuscles which thus simulated a reproductive condition. It is not
easy to see why MM. Pasteur and Bechamp should have fallen into error
in this instance. At all events Mr. Balbiani’s objections might be urged
against even the admitted instances of fission in organisms.

Photographs of fossil plants. — A splendid series of photographs representa-
tive of the flora of the coal measures has been sent to the Paris Exhibition by
Herr P. Goeppert, who is certainly one of our first European authorities on
the subject of coal-fossils. The photographs, 29 in number, are from the
typical plants of the Silesian coalfield, and are of the natural size. As the
species photographed are common to England and Silesia, there is a fine
opportunity for English palaeontological students.

Silicifed vegetable remains from Zambesi. — Some mud brought from the
Zambesi by Mr. Baines has been examined by Hr. John Lowe, who boiled it
in nitric acid and liquor potassse, and found it to consist of vegetable cells
perfectly silicified and mixed with numerous diatomaceee. Dr. Lowe has
described the various forms met with.

The plants of Iceland. — Under this title Mr. Isaac Carroll has a paper in
the Journal of Botany for April. He gives a long list of the plants found.
He is convinced that a few weeks or months spent in the North or North-
west part of the island would yield a rich harvest to the careful botanist.
The most remarkable feature in the Iceland flora appears to be its strikingly
Arctic character, shown by the absence of trees and the occurrence near the
sea-level of plants which in Norway and Lapland are -found at considerable
elevations. The number of lichens is small, the lava appearing generally

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to be destitute of them. Air. Carroll found none of tbe larger Parmelise, but
be states that Cetraria Islandica is found in great quantities on tbe deserts
of tbe interior, and be thinks that a greater variety might be found if ex-
amination were made of tbe flat- topped basalt mountains of tbe North-
west.

Distribution of the Diatomacece . — In a paper on tbe Protophyta of New
Zealand Dr. Lauder Lindsay, after enumerating several new species of
diatoms, and pointing out bow much remains to be done in tbe departments
of Desmidiacese and Palmellacese, makes some interesting remarks on tbe
cosmopolitan character of Diatomacese. He doubts whether any group of
plants has a wider geographical range, or whether any will be found, when
thoroughly known, to exhibit a greater number of cosmopolites, a larger
proportion of species which are independent of the usual restrictions of
climate or latitude, elevation or depth, aqueous or terrestrial growth — or a
wider range in geological time. They are to be found in every part of the
world hitherto explored by man, equally within the arctic circle as under
the line : they occur at great elevations on the highest mountains of the
world, as well as at great depths in the ocean ; in boiling or hot springs, and in
the ashes ejected from active volcanoes; in running as well as stagnant,
brackish or fresh as well as salt, water ; on the surface of soil of various
kinds ; on dung and other decaying organic matters ; on lichens, algae, and
other plants. They abound on the antarctic ice as far south as 78°, to
such an extent as to give colour to the said ice and the associated water.
Not infrequently they occur also in the dust of dust-winds, and they may
therefore be looked for in that of those which sweep over New Zealand from
Australia. Indeed, it is difficult to say where members of this cosmopolite
family will not be discovered.

Illustration of Natural Selection in Plants. — The recent continental discus-
sions as to the origin of new animal races from monsters have led M. Naudin,
the first of French botanists, to call the attention of the scientific world to some
remarkable instances of the origination of species and races by variation.
He states numerous examples, but we shall quote only the following. In
1861 M. Godron found in a batch of seedlings of Datura tatula (a plant
whose fruit is covered with spines) a single specimen whose fruit was per-
fectly smooth. The seeds taken from this plant produced in 1862 a number
of plants all of which resembled the parent. Their seeds gave rise to a
third generation similar to the second, and M. Naudin has seen the fourth
and fifth generation in his own museum. In all he says there are a hundred
individuals not one of which shows the slighest tendency to return to the
character of the typical species. They in fact constitute an entirely new
race. By crossing them with the original stock, M. Godron has obtained
forms which are identical with I), stramonium and D. Icevis, which have
hitherto been regarded as decidedly distinct species. If we add his
peculiar variety of D. tatula and call it D. inermis we shall have four species
produced by variation. M. Naudin thinks that the variations which give rise
to new species do not require the immense number of years for their produc-
tion, which is usually assigned to them, but that they occur brusquely , and
thus, the sought for connecting links have really no existence.

Spontaneous Movement of Colocasia esculenta. M. Lecoq describes the

SCIENTIFIC SUMMARY.

317

movement of this plant. They are quite spontaneous and depend upon
no common stimulus. The phenomenon displays itself at all periods of the
day and night, and there are often weeks of repose. The leaves, large and
small, seem to share in the motion, which is described as a sort of trembling.
Vide Coniptes Rendus , April 22.

CHEMISTRY.

Determination of Organic Impurities in Water. — Mr. Miles Smith has
written a letter to our contemporary The Laboratory, in which he states that
the investigations of Professor Wanklyn and Mr. Chapman have shown that
the ordinary mode of determining organic matters by evaporation is erro-
neous. If this be so it is a most important discovery, and it shows us how
unreliable must be the results of the analyses, so often published, of our metro-
politan waters. Professor Wanklyn has called attention to the fact that
the organic matters present in natural waters are liable to undergo de-
composition during evaporation, and that consequently the organic con-
stituents found in the dry residue left by a water are not to be taken as
a just representation of the organic impurities originally present in the
water. The nitrogenous organic impurities of waters are especially liable
to change, and if the evaporation be made in the presence of a powerful
alkali evolve their nitrogen in the form of ammonia. Wanklyn and Chapman
propose to detect and estimate the nitrogenous bodies in waters by taking
advantage of this reaction. In point of fact, they propose to make a kind
of Will and Varrentrapp’s analysis at moderate temperatures. The following
experiments illustrate the qualitative application of the method. Arti-
ficial waters were made by taking distilled water and putting into it small
quantities of well-known nitrogenised organic matters, and the artificial
waters were then examined. Eirst, however, it was shown that neither
nitrates nor nitrites give ammonia when boiled with alkalies, and sugar.
To half a litre of distilled water were added some sugar, baryta water, and
a nitrate, the whole being then boiled down rapidly in a retort very nearly
to dryness. No ammonia was evolved. The presence of ammonia in these
experiments was ascertained by means of Nessler’s test, which is well known
to be extraordinarily delicate. Nitrites treated similarly gave no ammonia.
It was also shown that if a small quantity of an ammoniacal salt be taken
and treated as above described, all the ammonia is evolved at the beginning
of the evaporation, and towards the latter part of the distillation the dis-
tillate comes over perfectly free from ammonia.

Chemical Examiners to the London University. — Professor Williamson,
Ph.JD., F.R.S., and H. Debus, Esq., Ph.D., E.R.S., have been re-elected
Examiners in Chemistry for the University of London. The salary of each
office is 175?. per annum.

Illuminating Power of the Gas of various Cities. — In the lectures which
Professor Frankland lately delivered at the Royal Institution, some very
useful comparisons were made showing the relative illumination-values of
the gas of different localities. Professor Frankland had the illuminating

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power tested "by the standard sperm candles, and the following are the
results: — Berlin, 15*5 candles ; Paris, 12-3; London, 12*1; Vienna, 9’0';
Edinburgh, 28-0 ; Manchester, 22-0 ; Liverpool, 22-0 ; Glasgow, 28*0 ;
Aberdeen, 35-0 ; Greenock, 28*5 ; Hawick, 30*0 ; Inverness, 25*0 ; Paisley,
30-3 $ Carlisle, 16 0 ; Birmingham, 15-0. Thus the gas supplied to Edinburgh
and Glasgow gives more than twice the light of the gas provided for
London. The above shows the average light given by the gas furnished in
London ; but, in particular instances, it only equals nine candles. The gas of
London, also, Prof. Frankland stated, is richer [fouler ?] than it ought to be
in the sulphur compounds, and in burning gives off too much poisonous sul-
phurous acid and other gaseous vapours injurious to health and property.
London gas is now worse than it was many years ago, although its methods
of manufacture have been cheapened by the discoveries of science, all new
inventions in this direction having been eagerly taken up by the gas compa-
nies, who, so far as is known, have not adopted a single invention which
would benefit the consumer. The lecturer concluded by saying “ gaslight
should have an illuminating power of twenty candles, below which no gas
is fit for household use ! ”

The description of Acetylene. — M. De Wilde describes a very interesting
-experiment in which acetylene is resolved into its elements (if we may use
such an explanation of the phenomena) by means of the induction spark.
He gives the following as the best mode of performing the experiment. In-
troduce the dry gas into a small eudiometer over mercury, and furnished
with two platinum wires about four millimetres apart. At the passage of
the spark, a light tuft of carbon is formed between the wires, and the
action stops. Agitate the eudiometer, so as to cause the mercury to knock
off the carbon, and the sparks which again pass will reproduce this phe-
nomenon. The eudiometer is shaken as often as necessary for the continua-
tion of the experiment. If operating with ten cubic centimetres of gas,
from fifteen to twenty agitations will suffice ; the experiment will then
proceed uninterruptedly. In ten or .fifteen hours all the acetylene will be
decomposed. The remaining gas submitted to eudiometric analysis is found
to be hydrogen. The acetylene should give its volume of hydrogen, but
there is always a diminution of about a fifth, which may, perhaps, be
attributed to the absorption of hydrogen by the deposited carbon, or perhaps,
to the formation of some trace of condensed hydrocarbons. Vide Bulletin de
la Societe chimique , vi. 267.

Nature of the Earth eaten by the People of Borneo. — The Chemical News
gives us the composition of the clay which is eaten so extensively by the
natives of Borneo. It states that some years ago the manager of the
Orange-Nassau colliery, near Zandjermasin, in the Island of Borneo, found
that many of his workpeople (natives) consumed large quantities of a kind of
clay ; a sample of this material was forwarded to Batavia for analysis, and the
following i3 the result in 100 parts : —

Pitcoal resin (organic matter volatile at red heat) 15*4

Pure carbon „ „ „

Silica ,, ,, ,,

Alumina „ „ ,,

Iron pyrites „ „ „

Vide Chemical News , May 10.

14-9

38-3

27-7

3*7

100*0

SCIENTIFIC SUMMARY.

319

Chemical Properties of Colchicia. — Mr. John M. Maisch publishes a paper
on this subject in a recent number of the American Journal of Pharmacy.
From an exam ination of a specimen of colchicia (the active principle
of colchicum) in the Philadelphia College of Pharmacy, which was
made with a view of clearing up the question of the reaction of this
substance, Mr. Maisch gives the following as its chemical properties. The
substance is a light yellow amorphous powder, possessing a very faint odour
and intensely bitter taste, sparingly soluble in ether, but easily soluble in
water and alcohol, the aqueous solution being slightly turbid, most likely in
consequence of the decomposition of a small portion into resin and colchicein.
Heated upon platinum foil, it fuses ; at a higher heat, it takes fire and burns
without leaving any residue. Placed upon moistened red litmus paper, the
blue colour is restored ; very faintly reddened litmus becomes blue also by
a concentrated aqueous solution. One drop of dilute sulphuric acid dropped
from a bottle giving fifty-two drops to the fluid drachm, consequently about
one-eighth of a grain H0,S01? when mixed with one grain of colchicia, re-
tained its acid reaction. One drop of the acid was mixed with one fluid
ounce of distilled water ; in five minims of this mixture, equal to about one-
seven hundred and seventieth grain H0,S01, one-sixteenth grain colchicia
was dissolved, and the solution now had a distinct alkaline reaction on
slightly reddened litmus paper ; but on heating this solution to the boiling
point, it had acquired an acid reaction.

Electrolysis of Alkaline Sulphides. — In a paper which appears in the
Annalen der Chemie , Herr H. Buff states that in the case of an electrolyte
under the influence of the electric current, the groups of elements travel in
opposite directions, carrying an equal amount of electricity of opposite
nature; they are electric-equivalent. From his experiments with alkalic
sulphides, the author concludes that the decomposition of the various mono-
or poly-sulphides of potassium or sodium always takes place in this manner,
that the metals travel towards the one electrode and all the sulphur towards
the other, or that a group of, for instance, five atoms of potassic pentasul-
phide is electric-equivalent to one atom of potassic monosulphide.

Soluble Phosphates in Cotton-fibre and Seeds. — At a recent meeting of the
Chemical Society, a paper by Dr. F. Grace Calvert was read in which it
was pointed out that seeds contain relatively more mineral phosphates than
other parts of the plants upon which they are borne, and which alludes to the
common practice of burning off the organic matters before proceeding to
search for the phosphates therein contained. From his experiments Dr.
Calvert has, however, been led to conclude that the whole of the phosphoric
acid or phosphates is merely held mechanically distributed throughout the
organic tissue, and in such a condition that they may be wholly extracted
by the action of water. Cotton yarn steeped for several hours in distilled
water furnished a solution containing appreciable quantities of phosphoric
acid, lime, and magnesia, and quantitative experiments were made upon
seven characteristic varieties of cotton, which had been carefully prepared
and carded in Manchester, for the purpose of determining the extent to
which the phosphates could be removed by washing. The results showed
by the uranium process amounts varying between *035 and *055 per cent, of
phosphoric acid thus dissolved, whilst traces only of this constituent could
VOL. YI. NO. XXIY. A A

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be detected in tbe ash. left upon burning tbe washed and dried cotton.
Similar experiments made upon wheat, French beans, and walnuts gave
like results, much phosphoric acid and magnesia being discovered in the
aqueous solution.

Sow to know 'pure Glycerine. — A writer in an American Pharmaceutical
periodical makes the following remarks relative to the best mode of testing
the purity of a sample of glycerine : — “ I should regard a glycerine as unob-
jectionable for medicinal purposes, if it forms a colourless mixture with twice
its volume of strong alcohol and of sulphuric acid ; and if, after previous
dilution with distilled water, it yields no turbidity, either cold or on heating
to the boiling point with sulphuretted hydrogen, ferrocyanide of potassium,
nitrate of baryta, oxalate of ammonia, or nitrate of silver. This last test I
regard as an important one, since 1 believe that all those compounds, which
impart to common glycerine a peculiar rancid odour, will reduce the silver
salt and impart a colour to the liquid on boiling, even though that odour may
be scarcely apparent, while pure glycerine is not affected by boiling with
nitrate of silver, although, like nearly all organic and many inorganic
compounds, it gradually assumes a darker colour on exposure to light.

Chloride of Silver in the Estimation of Iodine. — M. Kraut has devised a
useful mode of determining the iodine contained in organic hydriodates, of
which the Chemical News gives a short account. Herr Kraut digests the
solution for several minutes with a known quantity of recently precipitated
chloride of silver ; the increase of the weight of the chloride of silver is in
proportion to the amount of iodine. This method has the advantage of not
altering the substance beyond the removal of its iodine, which is replaced by
chlorine. — Zeitschrift fur analytische Chemie , iv. 167.

A Chemical Method for effectually cleaning Glass is given in a recently
published work on one of the processes of photography. It is simple, reliable
and completely efficient, and will we doubt not be found very useful by our
readers. It is as follows: — Dilute the ordinary hydrofluoric acid sold in
gutta-percha bottles, with four or five parts of water, drop it on a cotton
rubber (not on the glass), and rub well over, afterwards washing till the
acid is removed. The action is the same as that of sulphuric acid when used
for cleaning copper $ a little of the glass is dissolved off, and a fresh surface
exposed. The solution of the acid in water does not leave a dead surface on
the glass, as the vapour would ; if a strong solution is left on long enough
to produce a visible depression, the part affected will be quite bright. This
method is recommended in some cases for cleaning photographic plates.
Vide the u Tannin Process,” by Major Russell : R. Hardwicke, 192 Piccadilly.

Capillary Action and Chemical Decomposition. — The relation of the two
phenomena has been well demonstrated in a recent experiment by M.
Becquerel, who shows that both decomposition and combination are
influenced by capillary attraction. He takes a tube with two branches re-
versed, and makes in it a fissure, the width of which is infinitely small. He
pours therein a solution of nitrate of copper, and has found that no liquid
passes by the fissure ; but when placed in a vessel containing liquid pro-
tosulphuret of sodium, an electrical action takes place, and decomposition
and recomposition ensue, manifested by the crystals which appear on both
sides of the fissure. M. Becquerel has demonstrated the new and curious

SCIENTIFIC SUMMARY.

321

phenomenon that the capillarity of the fissure has a real influence on the
nature of the products of the decomposition ; that the salts or the crystalli-
sations are not always those indicated by theory ; that the double de-
composition often goes to the extent of reduction of the metal. — Vide
Comptes Pendus, May 13.

Supposed Aniline Colours from Flesh. — Herr Erdmann fancies he has dis-
covered a mode of producing the aniline dyes from flesh. Some time since
he observed that a piece of roast veal had a reddish appearance on its surface.
On transferring the red matter to various substances he found that under
the influence of heat and moisture if increased in quantity. The chemical
properties of the colouring matter to a certain extent resemble tryphenyl-
rosaniline. The fact that large numbers of vegetable and other spores were
formed with the red colouring matter is quite sufficient to account for the pro-
duction of the colour. The new dye (!) is evidently of the same order as
“ showers of blood ” and so forth, due to the development of low vegetable
organisms. — Vide Journal fur Praktische Chemie.

How to cover Floivers with Alum Crystals. — A trans- Atlantic contemporary
describes a simple method of covering fresh-flowers with alum crystallisa-
tion. It is as follows : — Make baskets of pliable copper wire, and wrap
them with gauze. Into these tie to the bottom violets, ferns, geranium
leaves, chrysanthemums — in fact, any flowers except full-blown roses — and
sink them in a solution of alum of one pound to the gallon of water, after
the solution has cooled, as the colours will then be preserved in their
original beauty, and the crystallised alum will hold faster than when from a
hot solution. When you have a light covering of distinct crystals that
cover completely the articles, remove carefully, and allow them to drain for
twelve hours.

The Proportion of Acid and Sugar in ripening Fruit. — At the meeting of the
Chemical Society, held on the 16th of May, an interesting paper by Dr.
A. Dupre, upon the above important subject was read by the secretary. It
has been stated by Continental chemists that, as the fruit ripens the acid
(malic and tartaric) becomes converted into sugar. This is the point to
which Dr. Dupre especially devoted his enquiries, and which he believes
he has cleared up by showing that the Continental view is inaccurate.
Dr. Dupre collected and experimented upon a hundred berries of Riesling
grapes gathered at intervals of a month, commencing with September last,
and the amounts of tartaric acid, free and combined, and also of sugar,
were determined in the separated j uices. The proportion of sugar increased
in order of time from 2-98 to 12V0, and even to 16*20 per cent, in the juice
of the perfectly ripe fruit ; whilst the entire berries showed but a slight
diminution or no appreciable change in the total amount of acid present.
The saccharine matter could not, therefore, have been directly derived from
the organic acid or its salts contained in the grape ; but the author thinks it
possible that the presence of such acid effects a change resulting in the
production of sugar similar to that known to occur in the conversion of
starch into sugar by the action of sulphuric and other acids. Further
experiments, even more decisive in their character, were made upon Gutedel
and Muscatel grapes, gathered at the same time and from the same vine,
but in various stages of ripeness. In some of the unripe berries there was

A A 2

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POPULAR SCIENCE REVIEW.

absolutely no sugar, whilst in others nearly ripe 8-87 per cent, of sugar was
found ; but the amount of free acid estimated in a hundred grapes was
almost the same in three samples of Gutedel, and actually increased with
the ripening of the Muscatel.

The Water in the Bronze Vase found at Pompeii, upon which the Daily
Telegraph was so eruditely classical, has been analysed. It was found per-
fectly limpid, and was hardly rendered turbid by a prolonged ebullition.
At the temperature of 20° C. its sp. gr. is 1*001, about that of distilled water.
The quantity of fixed matters left by evaporation was 1-032 gr. per litre.
The gases disengaged by ebullition consisted of air and carbonic acid. Lime
and magnesia were found in it ; also phosphates in a small quantity ; also
some traces of sulphates, and even silica and iron. There was not the slightest
trace of copper. — Vide Comptes Bendus, May 20.

GEOLOGY AND PALAEONTOLOGY.

The Formation of Gypsums and Dolomites. — At the meeting of the French
Academy on the 22nd of April, Dr. Sterry Hunt, the celebrated Canadian
geologist, read a paper on the subject. As usual he brought his profound
knowledge of chemistry to bear on the questions discussed and he stated the
following conclusions as resulting from his enquiries and investigations : —
1. That the mutual reaction of bicarbonate of lime and sulphate of mag-
nesia gave rise to sulphate of lime and bicarbonate of magnesia. 2. That
all the carbonates of magnesia arose from the decomposition of the primi-
tive silicates, aided by atmospheric carbonic acid. 3. That a double
anhydrous carbonate of lime and magnesia, having the composition of
dolomite, can be produced by heating slowly, from 120° to 150° C., a
mixture of lime and hydrated carbonate of magnesia. 4. That there are
dolomites which contain greater or less proportions of magnesia, whether
in the state of hydrated carbonate of magnesia or in the state of simple
hydrate.

A New Volcano in the South Seas. From a letter forwarded by our consul
at Navigators’ Islands, we learn that a volcano has just broken out at Manua,
about two miles from the islands of Oloscqa. It was preceded by a violent
shock of earthquake, which commenced on the 5th of September, and on
the 12th dense thick smoke rose out of the sea. Lava was thrown up, dis-
colouring the water for many miles round, and destroying large quantities
of fish. Wherever the ashes fell on the adjacent island they destroyed all
vegetation. Up to the middle of November dense smoke was still being
thrown up. It is said that the smoke rose higher than the neighbouring
island, which is over 2000 feet high. The consul has been unable to ascertain
whether there is any bank thrown up in the water.

A Deposit of Bituminous Gneiss. — At the last annual meeting of the
Swedish Academy of Science, M. Nordenskiold announced that a discovery
of a large deposit of bituminous gneiss, 33 metres in thickness, embedded
in layers of gneiss and mica-schist has been made in the hill of Nullaberg
in Sweden. It is composed in addition to feldspar, quartz and mica of a

SCIENTIFIC SUMMARY.

323

black substance wbicb seems to be a hydro-carbon, and resembles coal. M.
Nordenskiold, stated that infiltration was impossible, and that therefore,
there could be no doubt of the high antiquity of the strata of Nullaberg !

An International Arcliceological Congress. — The “ International Congress
for Primeval History,” which was founded a few years ago at Spezzia, is to
hold its next meeting at Paris on the 17th of August next. The questions
to be dealt with are the following : — 1. Under what geological circumstances
and among what plants aud animals have in the different countries the
oldest traces of man been discovered? What changes in the division of
sea and land must have ensued since? 2. Were the caves generally in-
habited ? Were they inhabited by the same race and at the same periods ?
And, if not, how and by what characteristics are the inhabitants of the
caves and the epochs to be distinguished ? 3. Do the megalithic monu-

ments belong to one people which by degrees overspread various countries ?
What were, in that case, the migrations of that race and its gradual progres-
sive steps in art and industry ? What relation may there possibly be
between this race and the lake-dwellers who possess an analogous industry ?

4. Is the appearance of bronze in the West the result of an indigenous in-
dustry, of violent conquests, or of the opening up of new channels of trade ?

5. What are in the different countries the essential characteristics of the first
iron period? Is this time anterior to historical times? 6. What informa-
tion do we possess about the anatomical characteristics of the human races
from the most ancient times to the iron period ?

The Gold Mines in Canada according to the recent report of Dr. Sterry
Hunt, appear to promise a fruitful harvest for investors. The gold-bearing
rocks form part of the Laurentian area of Canada and New York, and Dr.
Hunt states, that there is nothing in their age inconsistent with the belief
that the mines will prove highly productive. All Dr. Hunt’s investigations
tend to show that the precious metal has a very wide range in Canada.

The Yorkshire Coal-question. — The question as to whether the experi-
mental borings in Yorkshire are likely to prove the existence of coal in the
u Eastern Levels,” was discussed in a paper read before the Yorkshire Philo-
sophical Society at one of its meetings in June. The paper contained an
account of an attempt to discover coal at Reedness on the right bank of the
Ouse, below Qoole. In the discussion which followed, Mr. Wain wright made
some remarks, showing that he had lately made inquiries in the neighbour-
hood of the borings, which had extended, according to the information
which had been furnished to him by persons who were conversant with the
matter, to a depth of 331 yards. He suggested that by an additional ex-
penditure of 200/. or 300/., they might ascertain whether any coal was there,
and whether it would be worth while getting it.

The Tin Mines of Banca. — Banca is an island between Sumatra and
Borneo, on whose tin-resources a fine work has been written by M. Yan
Diest. This latter has been translated by Dr. Le Neve Foster, and it con-
tains the following conclusions interesting to mining geologists : — l< 1.
In Northern Banca tin occurs in the granite in various ways and over a
large extent of country. 2. The rocks which surround the granite are
impregnated with ores and other minerals occurring in the granite for some
distance, usually not more than a mile and a quarter. 3. These minerals

324

POPULAR SCIENCE REVIEW.

and ores are chiefly deposited in little veins or bunches in the direction of
the planes of bedding or in the joints. 4. It is chiefly the sandstone which
has taken up these minerals, especially where the rock appears to he the most
metamorphose d. ’ ’

The Carboniferous Coal of Russia. — A monograph on the coal of Russia
has been published at St. Petersburg. It is by Lieut.-General de Helmerson,
and among other facts, it gives the distribution of the coal of the Carboniferous
age. This distribution is as follows : 1. On the eastern and western slopes
of the Oural mountains. 2. In the governments of Novgorod, Iver, Moscow,
Kalouga, Toula, and Riazan. The coal occupies a large elliptical basin, six
hundred versts in length and four hundred in width, in the centre of which
the town of Moscow is situated. 3. In Samara, a little peninsula formed by
the river Volga, near Stavrpool ; and 4. In the government of Ekaterinoslav,
where the coal-beds form a chain of low mountains called the Donetz, and
are associated with abundant deposits of iron, which latter have not at
present been worked for economic purposes j though they would well repay
the cost.

The Perforations in Spirifer Cuspidalis. — Professor W. King does not yield
his opinion on this point. He still contends that there is every probability of
the existence of perforations in the shell of this species. He states that an
imperfect testiferous specimen now in the Geological Museum of Queen’s
College, Galway, displays under a hand magnifier, here and there, par-
ticularly on the protective parts — as the medial furrow — patches of faint,
slightly-raised oval impressions. He does not mean to have these appear-
ances accepted as positive evidence of the existence of perforations, but he
thinks they bear so strong a resemblance to rather ill- defined markings,
undoubtedly arising from perforation often seen on metamorphosed specimens
of Delasma hastata and other allied carboniferous species, in their force and
arrangement as to render the existence of such a structure extremely
improbable. Vide Geological Magazine , June.

The Phosphate of Lime Bed in North Wales. — Mr. D. C. Davies has sent an
account of this curious deposit to the Geological Magazine. Our readers
will remember that Professor Voelcker called the attention of Agri-
culturists to this bed, two or three years ago. The bed occurs in the midst of
what Mr. Davies has already described as the middle or principal band of
the Bala limestone. It was first discovered at Cwmgwynnen but it has since
been found to extend for about two miles in a north-easterly direction and
for about the same distance in a south-westerly line. It has been worked
somewhat extensively at Cwmgwynnen, and here it may be studied best.
It is black in colour, has an average thickness of about fifteen inches, and
occurs in a bed, and not as a vein, as is sometimes stated by chemists. There
are plenty of traces of former life in the bed : thus, Mr. Davies has obtained
from it numerous casts of Modiola, Aviculopecten , Orthoceras, Orthis, Lingula,
and fragments of Trilobites ; but the fossils are not well preserved, their
organic structure having apparently been destroyed by chemical agency.
Mr. Davies regards this Phosphate bed as the remains of a Laminarian zone
of sea life, just as the wide stretching, ferruginous sandy fossiliferous layers,
in the same formation, with their fossils often broken and confusedly huddled
together, are the remains of the Littoral zone of the same period. The bed>

SCIENTIFIC SUMMARY.

325

as far as it has already been explored, gives an area of four miles long, by
about eighty yards in width — this being the depth to which it is worked at
Cwmgwynnen, in the nearly vertical strata, and at all points hitherto ex-
amined it maintains much the same dimensions.

The Origin of Petroleum. — The last number of the Canadian Naturalist
contains an abstract of a recent paper by Dr. Hunt, in which the author
alluded to the subject of the origin of petroleum. Dr. Hunt regards the
process by which animal and vegetable hydrocarbonaceous tissues have been
converted into solid or liquid bitumen, as a decay or fermentation, under
conditions in which atmospheric oxygenation is excluded, so that the maxi-
mum amount of hydrogen is retained by the carbon ; and as representing one
extreme of a process, the other of which is found in anthracite and mineral
charcoal, the two conditions being antagonistic, and excluding each other,
and the production of petroleum implying, when complete, the disappearance
of the organic tissue. Hence pyroschists, the so-called bituminous shales,
and coal, are not found together with petroleum, but in separate formations,
and it is to be borne in mind that the epithet bituminous applied to the former
bodies i3 a mistaken one, since they seldom or never contain any bitumen,
although, like all fixed organic bodies, they yield hodrocarbons by destructive
distillation. The fallacy of the notion which ascribes petroleum to the
action of subterranean heat on coal was exposed by Dr. Hunt, who stated
that the oil of the Trenton limestone occurs below the horizon of any
pyroschists or other Hydrocarbonaceous rocks.

Dozoon Canadense. — Dr. Dawson lately presented a paper on certain
discoveries in regard to the above fossil, before the Montreal Natural
History Society. He also exhibited a photograph of a remarkable specimen
of JEozoon Canadense, found during the past summer in the Laurentian
limestone of Tudor, Canada West, by Mr. Vennor. The rocks at Tudor and
its vicinity, which, according to the observations of Mr. Vennor, are Lower
Laurentian, have experienced less metamorphism than is usual in formations
of that age. And this peculiarity gives especial interest to the present
specimen, which is contained in a rock scarcely altered, and in a condition
not essentially different, from that of ordinary Silurian fossils. The matrix
is a coarse laminated limestone of a dark colour, and containing much sand
and finely comminuted carbonaceous matter. The fossil itself is of a flattened
clavate form, about six and a half inches in length, and with the septa of its
chambers perfectly preserved, exhibiting on one side a well-defined marginal
wall, produced by coalescence of the septa, and apparently traversed by small
orifices. Under the microscope the minute structures of Dozoon Canadense
can be detected, though less distinctly perceived than in some of the speci-
mens mineralised by serpentine. In some of the chambers there are small
amorphous bodies containing pointed silicious spicules, which seem to be the
remains of sponges that have established themselves in the cells after the
animal matter of Eozoon had disappeared.

The Classification of the Drift Deposits. — Mr. Binney writes to the
Geological Magazine for May, to comment on Mr. Hull’s attempted classi-
fication of the drift deposits of Lancashire and Cheshire. He states that
25 years since he gave the following classification of these deposits to the
Manchester Geological Society: — 1. Beds of stratified and unstratified

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POPULAR SCIENCE REVIEW.

gravel and sand, containing well rounded pebbles of primitive Primary and
later Secondary rocks. 2. Till, a thick deposit of marl or brown clay,
mixed with angular or rounded pebbles of various sizes without any order of
deposition. 3. Beds of stratified fine rolled gravel and forest sand, often
containing beds of clay or loam. 4. Deposits of gravel and sand, both
stratified and unstratified, found in the beds of valleys and low lands adjoining
rivers and brook courses. In addition to the above a bed of rich loam is
frequently found in the valleys, covering the last named deposit. Still he
thinks it very difficult to arrive at any satisfactory classification. In evidence
of this opinion he gives the following section of the deposits at Broadstairs
Colliery, near Hyde, which we confess it would be difficult , to classify
satisfactorily : —

ft.

in.

ft.

in.

1.

Clay

. 11

0

8. Quicksand and Loam .

6

0

2.

Quicksand

. 2

6

9. Gravel ....

3

0

3.

Strong Marl .

. 22

6

10. Loam ....

7

6

4.

Quicksand

. 2

6

11. Gravel and Sand .

3

0

5.

Loam with Pebbles

. 12

6

12. Clay and Loam

15

6

6.

Buck-leaf Marl

. 19

0

13. Gravel and Soft Marl

7.

Dry Sand

. 9

0

containing Pebbles .

10

0

Local Sandstones. — At a late meeting of the Geological Society of Glasgow
Mr. J. Wallace Young read a paper on this subject, in which he expressed
the following conclusions : 1. That in the greater number of sandstones
examined, the cementing material consisted of carbonates. 2. That very
considerable quantities of the carbonates of iron and magnesia frequently
accompanied the carbonate of lime, although no definite ratio seemed to exist
between them. 3. That these sandstones were harder the greater the pro-
portion of carbonates they contain. 4. Mica was found to be present in
nearly all those examined, and, with one exception, was of the white variety.
5. Soluble silicates were only found in three varieties, in any quantity, all
three belonging to the Old Red Sandstone ; 6. That the different shades of.
colour seen in those sandstones belonging to the last-mentioned rocks
appeared to be due solely to the peroxide of iron, and that the white rings
and spots so often observed have resulted from the reduction and subsequent
removal of the greater part of this iron.

Hungarian Oligocene Deposits. — Herr Hantken has presented a paper to the
Viennese Geological Institute on the subject of some oligocene strata which
have recently been exposed in a shaft sunk at Sarisap in Hungary. The
strata are about 160 feet thick, and are of marine and brackish origin. The
beds due to the latter are composed of a sandy plastic clay, containing shells
and seeds of Char a. The marine strata overlie the brackish water ones, a
bed of clay intervening between the two : 60 feet of sandstone are above the
clay, and contain the remains of Echinidce.

Cycadoidia Yatesii is the name given to a newly discovered cycad, which
has been carefully examined by Mr. Carruthers of the British Museum.
The specimens from which the description has been given, were found in the
iron and green sands of Potton which rest on the Kimmeridge and Oxford
clays and are covered by the Gault. The specific name has been given in
compliment to Mr. Yates, whose name is well and favorably known in con-

SCIENTIFIC SUMMARY.

327

nection with the order of plants to which the species now founded belongs.
The fossil belonged to an arborescent cycad resembling in aspect the tall
cylindrical stems of Cycas or Macrozama, and differed in this respect from the
spherical or ovoid trunks belonging to the genus, which were described by
Buckland and Lindley. The cellular axis was relatively very large. The
pith has disappeared, except in one of the specimens, where there are still
some indications of it, and of the vascular bundles which abounded in it.
The woody cylinder surrounding the pith consists of two rings, everywhere
pierced by medullary rays, which are often so large as to separate the rings
into numerous series of woody wedges, as in recent Cycadece. The presence
of discs on the woody vessels has been detected both by Professor Morris and
Mr. Carruthers. The inner surface of the woody cylinder is marked by
numerous narrow grooves and perforations, formed by the vascular bundles,
as they passed from the pith into the wood. The outer surface has similar
scars, produced by the vascular bundles, which passed from the wood to the
leaves j but they are here larger and more regularly disposed than on the
inner surface. Between the wood and the bases of the petioles there inter-
posed a very thin layer of cellular tissue, through which the vascular bundles
passed in an upward direction towards the petioles.

MECHANICAL SCIENCE.

Institute of Naval Architects. — During the month of April this Institute
held its annual meeting, and, as in preceding years, some of the papers were
of the highest scientific interest. Mr. I. B,. Napier read a paper on some
steel tug- boats constructed for the Godaverv, having the extraordinary propor-
tions of 140 ft. length, 25 ft. breadth, and only 1 foot draught. The plating is
of galvanised steel with a view of reducing to the utmost the weight and
frictional resistance and securing durability. An awning or roof, also plated
with steel is provided, forming an integral part of the structure, being con-
nected with the bottom by lattice-frames, so as to increase the depth, resisting
bending strains, and thus to render the vessel rigid. The engine has a pan
of 11-inch cylinders, 4-ft. stroke, supplied with steam at 150 lbs. pressure,
from a tubular boiler, of the locomotive type. The paddles are at the stern,
and the propelling surface is not less than of the augmented surface. It
is thought that the speed may reach 12 miles an hour.

In a paper on the Stowage of Merchant Vessels by Mr. Barnaby, a
practical plan was suggested for ascertaining the crankness or stiffness of
the vessel, due to loading. Mr. Barnaby suggests the securing the ship to
the wharf-side, by a chain with a slip, when she is lifting with the tide.
Having thus been heeled over a few degrees she is to be suddenly released
and the oscillations in a given time counted. In some experiments on the
u Madeline ” yatch, the shifting of a weight of 86 cwt. on the mast caused
the time of 5 oscillations to vary from 21 to 26 seconds.

Mr. Bourne described a system of designing the water lines of ships, soi
that the lateral displacement of the water for a given progress of the vessel
should obey the same law as to velocity as a pendulum.

328

POPULAR SCIENCE REVIEW.

Two very important papers on apparent negative slip of screw propellers
were read, one by Professor W. J. M. Rankun, and the other by Mr. W.
Froude. In the former, the existence of negative slip is explained by the
fact, that the position of the propeller places it in the crest of a following or
filling wave under the ship’s counter, so that the water which the screw lays
hold of has a temporary forward velocity over and above the permanent
velocity of the wake ; that temporary forward velocity may be many times
greater than the permanent velocity of that current whose momentum is
equivalent to the resistance of the ship ; and thus any amount of negative
slip may be accounted for. In Mr. Froude’s paper the negative slip is attri-
buted to the action of the screw on the dead-water carried by the ship in
front of the stern-post, and which water has to be suddenly removed twice
at least in each revolution of the screw. The block of dead-water thus
carried, in the screw-well of a timber line-of-battle ship, is estimated at
from 5 to 6 tons. Its dispersion, as the blade of the propeller sweeps past
the stern-post, is accompanied with a violent shock on the screw-shaft,
whilst the dispersed dead-water is instantaneously replaced by a fresh
volume, to which the velocity of the ship must be rapidly imparted ; and
the communication of velocity to the water of replacement forms an adven-
titious addition to the ship’s resistance. In this struggle between the
propeller and the dead-water, although a precise balance is maintained
between the propulsive shock delivered and the adventitious resistance
called into play, yet a great deal of force is exerted to no purpose by the
propeller and the mean speed of rotation of the propeller must undergo
great reduction, in such a manner as to be capable of exhibiting, in almost
any degree, the phenomenon of negative slip. In other words, whilst in
reference to the speed of the propeller whilst acting in the free-water
outside the dead-wood, the slip is always positive ; in reference to the mean
speed, including the retardations in passing the dead-wood, the slip is
negative. Mr. Froude suggests as a means of testing his theory, the chrono-
metric registration of the speed of rotation of the screw shaft, and as a
means of obviating the sources of loss which his theory indicates, he would
place the propeller not merely abaft the rudder but at some tangible distance
clear of it. In some small scale experiments Mr. Froude obtained a result
from thus removing the propeller equivalent to doubling the horse power.

Captain L. G. Heath R.N., who has had great opportunities of observing
the effect of shot on targets, proposed a new system of armour-plating, in
which the more or less perishable wood-backing is entirely dispensed with.
He places the armour-plate, made as heavy as possible, on horizontal girders,
so as to carry it about 14 inches in front of the ordinary skin of the ship,
leaving an air space of that depth between. He anticipates that shot will
be broken up in passing through the armour-plate, and will merely splash
the vital part.

During the meetings drawings of a self-registering floating apparatus, for
measuring the height of waves, was exhibited ; the instrument having been
contrived and used with success by Admiral Paris, of the French Navy.

Channel Ferry. — We mentioned in our last number, the proposed tunnels
between this country and France. Messrs. A. and I. Inglis have now
published, as a more feasible scheme, the details of a ferry steamboat of

SCIENTIFIC SUMMARY.

329

440 feet length, and 57 ft. beam, on which the railway cars could be run
bodily, and which, from her great size, would be steady enough to obviate
the danger of sea sickness. The engines proposed are oscillating engines of
1500 collective horses’ power, and the passage between Dover and Calais
would be made in one hour.

Mechanics of Flight. — An extremely interesting paper on this subject was
read by Mr. Wenham to the Aeronautical Society. The subject is too
difficult and complex to be explained briefly, and therefore we will only say
that Mr. Wenham has brought into the explanation of flight, the effect of
the forward motion in retarding descent. Imagine a parallelogram 10 ft.
long by 2 ft. broad, weighing 20 lbs. Such a body would descend in still
air at the limiting rate of 1,320 ft. per minute, the resistance of the air
put in motion by the plane balancing at that velocity the effect of gravity.
If now a force be applied horizontally so as to carry the plane with its long
side forwards at a speed of 30 miles per hour, then the motion of the plane
being both downwards and forwards, a great volume of air will pass under
the front margin of the plane, and will be carried downwards before leaving
the hinder margin. The weight of air thus put in motion will be enormous,
and the descending velocity of the plane proportionately reduced. Mr.
Wenham calculates that the velocity of descent would in these circum-
stances be reduced to of the passive rate of descent, or would not exceed
83 ft. per minute. Each particle of air would then be moved downwards
t8o of an inch by the passage of the plane, and conversely if this inclination
were given to the plane it would move forwards without descending. Mr.
Wenham finds that few birds can raise themselves vertically in the air, the
exertion in that case being excessive. The eagle can only lift itself from
the ground, by running with outstretched wings till its velocity having
become sufficient, it glides into the air as if sliding on a frictionless plane.

Electric Loom . — In one of the looms in the Paris Exhibition, electricity
has been applied in a most ingenious manner to effect the immediate
stoppage of the loom on the breakage of a thread, the emptying of a bobbin,
or other trifling accident requiring the notice of the attendant.

Type Writing Machine. — Mr. John Pratt, of Alabama, U. S., has recently
brought out a machine for type writing, which was exhibited at the recent
Soiree of the Institute of Civil Engineers, and which promises to be of
much service. The writing is effected by pressing a series of keys like
those of a piano-forte, which move into the necessary position a square
frame carrying the type, and the letter is then impressed on the paper, by
the stroke of a hammer, pressing the paper and an interposed carbonised
sheet against the type. A document can be printed by the machine in about
half the time necessary to write it in the ordinary way. Mr. Pratt thinks
that if the machine comes into use it can be manufactured for three guineas,
so simple and compact has it been made. A machine for stereotyping
on a similar method, also the production of American ingenuity, is exhi-
bited at Paris.

Steel Armour Plates. — Renewed experiments have been made on steel as
a material for armour-plating, and have been attended with more success
than heretofore. The plates tested were 9 ft. by 4 ft. by 7 ins. They
consisted of interposed laminae of iron and steel, and appeared to be welded

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perfectly solid. In almost every case they were completely perforated by
the 7 -inch gun, with Palliser chilled shot, and charges of 15 to 20 lbs. of
powder. One iron and one steel-faced plate resisted complete perforation,
with the smaller charge, and the most that can be concluded at present is,
that the laminated steel and iron plates exhibit equal resisting powers to the
best rolled iron plates hitherto produced. It is remarkable that the chilled
hot which penetrated but did not get through the plates remained perfect
and unbroken.

Flow of Solids. — M. Tresca has explained to the Institute of Mechanical
Engineers, now holding a meeting at Paris, his views on the flow of solids,
to which we have before alluded. The experiments on which M. Tresca’s
theory is founded are of this nature. If a hollow cylinder closed at the
bottom end, have a cylindrical block of lead fitted to it, and the hollow
cylinder have a round hole in the centre of the bottom, a powerful pressure
on the top of the block will produce a cylindrical jet of metal, having a
section equal in area to the hole in the cylindrical vessel. If the solid block
be replaced by a series of parallel laminae of the same substance, and a
section of the block be made after the pressure has been applied, it will be
found that the laminae, though compressed, remain parallel and flat over all
the surface excepting that affected by the formation of the jet, and the jet
itself will be found to consist of a series of cylindrical envelopes or tubes,
one for each lamina of the original block. The same results have been
obtained by M. Tresca with tin, silver, copper, aluminum, iron, steel, and
other substances. If a series of holes be made in the bottom of the
containing vessel, then a series of jets are formed, but each jet more or less
affects the formation of the others. M. Tresca has similarly studied the
flow through lateral orifices and the unequal distribution of pressure in the
mass, due to the flow, and he has applied these results to explain the opera-
tions of forging and rolling. By oxidising specimens of rolled and forged
iron, he found that all the elements of the original piece are drawn out in
parallel lines, from the surface to the centre of the bar ; precisely as in
the case of the jets produced by pressure ; so that, the changes of form
produced by forging may be considered as the results of successive flowings,
effected by each of the individual forces exerted on the work forged. These
changes of form take place from particle to particle according to a geome-
trical order which admits of mathematical calculation. And the theory
may thus supply definite rules for metallurgical operations. An abstract of
the paper, which is extremely interesting, will be found in the Engineer of
Jure 7.

MEDICAL SCIENCE.

Development of Fungi in the Kidneys. — In the last number of Beale's
Archives , Dr. M. Tonge gives the details of a curious case of Phthisis, ac-
companied by the development of fungous growths in the substance of the
kidney. The pelvis of the left kidney was filled with a yellowish-white

SCIENTIFIC SUMMARY.

331

pultaceous substance adherent to the apices of many of the pyramids. Micro-
scopical examination of this proved it to consist of the sporules and mycelium
of a microscopic fungus, apparently a species of oidium, which had the fol-
lowing characters : — 1. Round or oval vesicles, single or grouped, containing
one or more globules (probably oil globules or minute sporules), and some-
times granular matter. 2. Elongated vesicles united at their ends so as to
form continuous cylindrical tubes branching dichotomously, sometimes ter-
minated by strings or groups of round or oval cells, lateral development of
these cells being also not uncommon. The tubes contained oil globules and
granular material. In some instances it could be perceived that the tubes
were empty, the liquid material having escaped.

Action of Hydrosulphuric Acid on the Blood. — The observations which
were some time since made by Herr Hoppe-Seyler have been fully corro-
borated by the more recent inquiries of Herren Kaufmann and Rosenthal.
These physiologists assert that the action of the above gas is simply to
asphyxiate. The remedy suggested in case of poisoning is introduction of
oxygen into the blood by means of artificial respiration.

Absorption of Fat — According to the observation of Herr Letzerich, fat
and albumen are not absorbed by the epithelium of the intestine, but by
vacuoles between the epithelial cells, which lead directly from the intestine
into the lacteals. Eat in the epithelium he considers pathological, and
generally due to excess of fat in the food. — Vide Virchow's Archiv, xxxvii.

Cervical Bibs. — In one of the late numbers of Virchow's Archiv , M. Stieda
of Dorpat, describes an interesting case of the above. The case was that of
a woman, aged 30, and has been reported in the Journal of Anatomy, No. 2.
Except that the left cervical rib was ossified to its vertebra, whilst the right
was articulated to it by a moveable joint, both ribs closely resembled each
other. In each a head, neck, tubercle, and body, were found ; the anterior
end of the body was pointed and connected by a ligament to a plate of
cartilage attached to the anterior end of the first thoracic rib. The subclavian
arteries had been removed, so that M. Stieda could not determine their
relations. The thoracic vertebrae and ribs, and the lumbar vertebrae, were
normal in number.

Absorption by the Skin. — A memoir on this subject has been laid before the
French Academy, by M. Ch. Hoffmann. His experiments have been' made
on digitalis, iodine of potassium, and chloride of sodium. He comes to the
following conclusions: — 1. Chemical and other agents, dissolved in water,
penetrate slowly but obviously into the animal economy, by the external
integument, and it is only when the blood and other fluids are saturated by
them that the organism expels them. 2. All medicaments are not absorbed
in the same degree. 3. The contradictory results hitherto obtained result
from the insufficient length of the time devoted to the experiments.

Action of Compressed Air on the Circulation and Respiration. — M. Yivenot
concludes from his experiments that the action of compressed air is to
diminish the frequency of the pulse. This slackening is, on the average,
about six and a half pulsations per minute. The cause is purely mechanical:
the increase of pressure on the surface of the body diminishes the calibre of
the small vessels, and increases the obstacle which the vascular walls oppose
to the current from the heart. This diminution of the vessels may be seen

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on the conjunctiva, on the ear of the rabbit, and on the vessels of the retina.
Rarified air gives opposite effects. On the respiration, it produces a double
effect ; 1. an augmentation of capacity of the lungs — a mechanical dilatation ;
2. the introduction of a larger quantity of air, since not only the lung has
greater capacity, but the air is compressed. Compressed air, the author
thinks, therefore, a useful agent in the treatment of certain diseases
(emphysema, atelectasis, tuberculosis, pleuritic effusions, etc.) ; and so much
the more valuable, that no other agent is calculated to fulfil the same
indication. — Virchow's Archiv , 1866.

Obituary. — We regret to have to announce the death of two of the most
illustrious members of the French profession, M. Jobert (de Lamballe), and
M. Civiale, the inventor of lithotrity.

Crystals in the Blood , in Leukamia. — Professor Neumann of Konigsberg,
communicates a paper on this interesting pathological subject to Max
Schultze’s Microscopical Journal. The formation of the crystals did not occur
until long after the blood had been drawn. A large number of crystals were
formed on each drop of blood. These were brilliant delicate symmetrical
needles, which were found on minute examination to possess the form of an
elongated octahedron. Some which appeared to be incompletely formed
represented merely a four-sided pyramid with a rounded base. The length
of the perfect crystals varied between 0*016 and 0*075, and the angles of the
optical longitudinal section were between 18° and 162°. The crystals
were insoluble in cold water; in boiling water they disappeared, but
whether by solution or disintegration the author could not decide, but
is inclined to think the latter, as he never observed any recrystallisation on
cooling. Neither alcohol, ether, chloroform, nor glycerine, even after long
exposure, had any effect upon them. Acetic, tartaric, and phosphoric acids
slowly dissolved them, as did also very weak solutions of soda and potass.
The action of the mineral acids was peculiar ; hydrochloric and nitric acid
in strong solutions dissolved the crystals, which withstood the same acids
in the concentrated form, in which, however, they become apparently softened
and were usually bent into an S form, or became crescentic. Strong sul-
phuric acid destroyed the crystals, which remained unaltered only in a
moderately weak solution. Ammonia dissolved the crystals very slowly ;
they were unaffected by the putrefaction of the blood even after several
weeks. — Vide Quarterly Journal of Microscopical Science, No. xxvi.

The Removal of Opacity of the Cornea. — Some very curious facts relative
to the action of sulphate of soda on the cornea, are pointed out in a memoir
just read before the French Academy by M. De Luca. This savant had
tried the Vinum Opii and other remedies so much employed in treating
opacity of the cornea, but found their results unsatisfactory. It then oc-
curred to him that as sulphate of soda retains the fibrine of blood in solution,
it might have the effect of dissolving away opaque portions of the cornea.
At first he tried the experiment with solution of the sulphate in distilled
water. This fluid he dropped into his patient’s eyes, and the results were
found, to a certain extent, satisfactory. Believing that the solid sulphate
would produce still better results, he employed it in the state of very fine
powder; dropping it into the eye of the patient. This method proved to be
the most effectual, and if we are to believe M. De Luca, it was most sue-

SCIENTIFIC SUMMARY.

333

cessful. In one or two cases where the opacity was so decided as to produce
nearly total blindness, a considerable amount of vision was restored to the
patient. — "Vide Comptes Pendus , May 27.

Isolation of Pseudomorphine. — Pseudomorphine was discovered about
thirty years ago by Pelletier, but from the exceedingly small quantity ob-
tained by him, he was unable to give an exact method for its preparation.
This, however, has now been done by Herr Hesse, who has published a
paper on the subject in the Annalen der Chemie. Hesse finds that it
accompanies morphine in Gregory’s method, and may be separated from
that body by adding excess of ammonia to the alcoholic solution of both
alkaloids ; the morphine is precipitated, the other remains in solution.
Pseudomorphine is tasteless, insoluble in water, alcohol, ether, chloroform,
carbonic bisulphide, and dilute sulphuric acid, easily soluble in potash, soda,
or lime solutions, and in alcoholic solution of ammonia, sparingly so in
aqueous solution of ammonia ; it does not neutralise the acid reaction of
even the smallest quantity of chlorhydric acid ; it dissolves in concentrated
sulphuric acid with an olive green, in concentrated nitric acid with an in-
tense orange red, in ferric chloride with a blue colour. At 120° it loses 2
eq. water of crystallisation ; at higher temperatures it turns yellow and
decomposes without melting.

The Physiological Action of Digitalis has recently been very fully investigated
by M. Legroux, who has thus formulated the conclusions at which he has
arrived : — 1. If given in a poisonous dose, digitalis acts directly on the heart ;
in a therapeutic dose, it excites primarily the contractility of the capillary
vessels, and only secondarily influences the circulatory centre by re-estab-
lishing the equilibrium of the circulation. If this theory be adopted,
digitalis is a sedative of the circulation, inasmuch as it calms its irregular
action ; but, if it really possess this power, it is by an exciting and tonic
action. 2. The influence of digitalis on the temperature, the secretions,
nutrition, the uterine contraction, haemorrhages, &c., can only be explained
by its exciting action on the ultimate filaments of the great sympathetic.
This theory explains and justifies the favourable results obtained by the
employment of digitalis in fevers, cerebral affections, haemorrhages, and
dysmenorrhoea, as well as in congestions, dropsies, and the circulatory affec-
tions, accompanying cardiac lesions. — Vide Gazette Medicate de Paris, April
27.

The Study of Human Histology is greatly facilitated, according to the recent
statements of Herren Kolliker, and Cohnheim, by employing chloride of gold
to stain the tissues. This substance appears to have a very peculiar effect on
the histological elements. Tissues which have been soaked for some time
in a weak solution of it, and afterwards exposed to light, are found to ex-
hibit certain parts, ex gr. nerve-fibres, connective-tissue corpuscles and cells
in general, stained of a bluish, violet, or reddish colour, while other parts,
ex gr. intercellular substance, &c., are untouched. The fresh tissue should
be covered with a little of a solution of from 1 to *2 per cent, of chloride of
gold in distilled water (the strength must be made to vary according to the
thickness of the object and other circumstances), and allowed to stand until
it assumes a straw-yellow colour. It should then be washed and placed in
very dilute acetic acid (1 to *2 per cent.). The colour will in the course of

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POPULAR SCIENCE REVIEW.

some hours gradually develop itself. Nerve-fibres and connective-tissue
corpuscles are exceedingly well shown by this method, which will probably
come into very general use as a sort of correlative of the 11 silvering ” method
with dilute solutions of nitrate of silver. As a general rule, what the silver
stains the gold does not, and vice versa. — Vide Journal of Anatomy and
Physiology.

Development of striped Muscular Fibre. — Herr Eckhard has published a
paper in Henle und Pfeuffer’s Zeitschrift, in which he points out, as Huxley
and others have done before him, that this species of muscular fibre is not
developed from cells, but from a blastema. This blastema is nucleated, but
the nuclei takes no share in the produce by which the internuclear matter
is converted into fibre. Eckhard has also made observations on development
of the heart of the chick, and states that at no period can cells be seen, but
here, as in the muscles of the skeleton, the earliest stage is a nucleated
blastema which rhythmically contracts before fibres make their appearance,
the latter are developed from the internuclear matter directly. Lockhart
Clarke had previously pointed out the fact that the development of the
cardiac muscular fibre is the same as that of the voluntary muscles.

What is Hippuric Acid ? — An abstract of the Researches of Shepard and
Meissner, appeared in the Centralblatt , and has been again abstracted in the
last number of our well-edited contemporary, the Journal of Anatomy. The
inquiries of these savants throw much valuable light on the above question.
However, Shepard and Meissner .having entirely failed to find hippuric acid
in the blood of herbivora, conclude that it is formed in the kidneys. This
conclusion is supported by previous experiments of Meissner, who could find
no hippuric acid in the blood even after the kidneys had been extirpated.
After introducing benzoate of soda into the stomachs of dogs, they found
benzoic acid in the blood and saliva, and succinic acid in the sweat ; but
hippuric acid could only be found in the urine. In opposition to Kiihne and
Hallwachs, they assert that they have satisfactorily proved that the conversion
of benzoic into hippuric acid takes place quite independent of the liver.
After ejecting hippuric acid into the stomach of rabbits, they found extremely
little hippuric acid in the blood, though abundance was found in the urine ;
on the other hand, benzoic acid and urea were abundantly found in the blood.
When, on the other hand, hippuric acid was injected subcutaneously,
hippuric acid was found in the blood in large quantities, but no benzoic acid.
Hence it appears that hippuric acid is decomposed in the digestive tract into
benzoic acid and glycocoll, the latter of which, according to Kiithe and
Horsford, is easily transformed into urea. Meissner and Shepard have
found in the cuticle of plants a substance having the following formula
C14II12O10, which is nearly identical with the formula for cinchonic acid
C14H12012. From this substance they suppose the hippuric acid found in
the urine of the herbivora to be derived.

Civiale's Collection of Calculi. — Shortly before his death, M. Civiale pre-
sented his splendid collection of calculi to the French Academy. At the
same time he offered some important remarks upon the various forms,
physical and chemical, of calculi. — Vide Comptes Rendus, May 13.

A useful form of Poultice , the invention of M. Genevoix, is now on
view at the Paris Exhibition. It consists of an impermeable tissue, enclosing

SCIENTIFIC SUMMAKY.

335

a double layer of swanskin, which is wetted with a decoction of marsh-
mallow, linseed, or poppy heads, and which maintains a temperature of 70°
centigrade for more than twelve hours.

Termination of the Ne?'ves in Muscle. — The views expressed by Dr.
Lionel Beale in the several admirable memoirs he has published on this
subject continue to be confirmed by their author’s further researches. In
the last number of his Archives of Medicine , Dr. Beale gives some very
beautiful drawings of the plexuses of dark-bordered fibres, and those who
desire to see the relations of ultimate nerve-fibre to ultimate muscle-fibre
can do no better than consult these drawings.

The cause of Muscular Contraction. — The numerous and convincing experi-
ments of Dr. C. B. Badcliffe, have already converted most of our modern
physiologists to the doctrine that muscular contraction is nothing more than
electrical discharge. While the muscles are at rest, the electric charge
causes a condition of repulsion among the muscular elements by virtue of
which the muscle is increased in length. The instant this electricity is
discharged the repulsion ceases, and the natural attraction of the muscular
particles coming into play, the muscle shortens. That such a discharge ac-
companies the muscular contraction is now one of the admitted facts of
physiological science. The state of things in Rigor mortis , where there is the
most complete degree of discharge, is a very powerful argument in favour of
Dr. Badcliffe ’s views, but an appeal to the ordinary phenomena of nervous
pathology puts the discharge theory of muscular contraction beyond all
question. We call attention to these circumstances, because we notice in
the last number of Dr. Beale’s Archives , a paper by Mr. Baxter, on muscular
contraction, in which the author makes a wholesale appropriation of Dr.
Badeliffe’s theory, but carefully avoids allusion either to Dr. Badcliffe’s
treatise, or to his papers read before the Boyal Society. Perhaps Mr.
Baxter is unfamiliar with Dr. Bacliffe’s researches. If such be the case,
the sooner he informs himself upon them, the better.

. METALLURGY, MINERALOGY, AND MINING.

Iridium in Canada. — In one of the Canadian journals, it is stated that a
Mr. Meves of Madoc, has found iridium among the materials which exist
with gold in the Bichardson mine. This is not in accordance with the
report of Dr. Sterry Hunt, and Mr. Michel $ but as Mr. Meves’ specimens
were derived from a different portion of the vein, it is possible that the
existence of iridium may be a fact. Iridium is a hard metal, and exists in
the Californian gold ; its presence in the gold coined at the United States’
mint caused the destruction of several valuable dies, and thus led to its
discovery.

A New Fuel. — This is a modified peat-fuel for which Mr. Lee has taken
out a patent. It is said to possess many advantages over coal, as regards
economy and production of steam-power. The Shipping Gazette gives the
following account of some experiments lately made with this fuel : — u The
results arrived at were considered to prove that peat, when properly dried
YOL. YI. — NO. XXIV. B B

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POPULAR SCIENCE REVIEW.

and submitted to a certain process, and then saturated in oil, has greater
heating power than the best Welsh coal. The advantages possessed by this
peat fuel are the rapidity with which a fire can be lighted, and economy in
working and space. Put a few blocks in the furnace, apply a match, and in
an instant the whole is in a mass of flame. Very little stoking is required.”

Electro-Magnetism in Iron Smelting. — An experiment has been tried at
Sheffield to test the action of electro-magnetism, on the smelting of iron,
and if we are to believe reports the results were highly satisfactory. The
following account is given of the experiment: — A fixed electro-magnet
is placed opposite an opening in the side of the furnace : the magnet is
excited by means of a Smee’s battery, and the current of magnetism is
directed into the molten metal. The effect is described as being surprising.
The metal appears to bubble and boil ; and the quality of the iron is so
much improved that for toughness and hardness it can hardly be equalled.

Gun-cotton in Mining — It is stated that by combining ammonia with gun-
cotton, its liability to spontoneous combustion is removed without injuring
its explosive qualities.

Pozzolana. — A late number of the Mining Journal contains a letter from
Naples announcing the discovery of a valuable deposit of this cement.
It has been found at the foot of Vesuvius, on a property called Torre
Bassano. The strength of this cement is said to be equal to, if not greater
than that of the celebrated pozzolana of S. Paolo, of Rome, whence
England has generally drawn her supplies. In 1852 there was a “ find ”
of the same material, and the Government of that day were so satisfied as
to its merits that they used it in the construction of the only dry dock in
Naples. On making some alterations in this dock recently it was with the
greatest difficulty that any impression could be made on the pozzolana
above mentioned, proof being thus given of its great excellence. The
Government has already contracted for a considerable quantity of it for the
construction of the new mole, and for other public works in Palermo, and
much has been exported to Alexandria.

Bismuth in Australia. — We learn from the Melbourne Age that a discovery
has recently been made in South Australia of a lode of bismuth, samples of
the metal being now to be seen at the Melbourne Exchange, to which place
it has been sent from the neighbouring colony. This metal is very valuable
if found in quantity, and it is stated that the lode discovered contains abund-
ance of rich u stuff,” but being situated about 200 miles in the interior, some
serious difficulties in the cost of carriage have been encountered. Trouble
was also experienced in getting the metal smelted, but a quantity of it was
sent to England in ingots some time since, and it is expected the supply
will be kept up.

A Botary Blower , deserving the attention of all who are engaged in
tc blast ” operations, is now exhibited in the French Exposition. It is the
invention of Messrs. Roots of Connersville, Indiana, and is, we believe,
extensively used in America. It is an improvement upon the ordinary system
of a cylinders,” and has not the drawbacks either of the cylinder or the fan.
It requires less than half the power to run it of even a fan ; its speed is
not excessive, being only from 200 to 300 revolutions per minute, whilst the
ordinary speed of a fan is ten times greater j and at the same time it can

SCIENTIFIC SUMMARY.

337

force air at any pressure whatever, if sufficient steam power be used, without
any of the friction and loss of power incidental to a blowing cylinder. The
principle is that of two irregularly-shaped blowers revolving in an oval
cylinder. These blowers are so arranged that as they revolve, the air which
enters is pent up between them, and driven with any required force through
the escape-hole.

Japanese Alloys , their Nature and Nomenclature. — The Builder gives
the following abstract of a paper which appeared some time since in an
American scientific journal: — The first alloy given maybe regarded as a
weak Japanese imitation of jewellers’ gold. This Shakdo is an interesting
alloy of copper and gold, the latter metal in proportions varying between 1
per cent, and 10 per cent. Objects made from this composition, after being
polished are boiled in a solution of sulphate of copper, alum, and verdigris,
by which they receive a beautiful bluish-black colour. 1 Gin shi hu icliij
(‘ quarter silver ’) is an alloy of copper and silver, in which the amount of
silver varies between 30 per cent, and 50 per cent. Ornamental objects
made from this composition take, when subjected to the action of the above
solution, a rich grey colour, much liked by the Japanese. Mokume is a
mixture of several alloys and metals of different colours associated in such
manner as to produce an ornamental effect. Beautiful damask work is pro-
duced by soldering together, one over the other in alternate order, thirty or
forty sheets of gold, shakdo silver, rose copper, and gin shi hu ichi, and then
cutting deep into the thick plate thus formed with conical reamers, to pro-
duce concentric circles, and making troughs of triangular section to produce
parallel, straight, or contorted lines. The plate is then hammered out until
the holes disappear, manufactured into the desired shape, scoured with ashes,
polished, and boiled in the solution already mentioned. The boiling brings
out the colours of the shakdo, gin shi hu ichi, and rose copper. Of brasses
(Sin ehu) the finest quality of brass is formed of 10 parts of copper and 5
parts of zinc. A lower quality, of 10 parts copper and 27 parts zinc. Kara
kane (bell metal) varies from first quality — copper 10, tin 4, iron f, zinc If,
to fourth quality — copper 10, tin 2, lead 2. The best small bells are made
from the former quality, and large bells from the latter.

Iridium from Blende. — Herr Boettger has pointed out that the flue-dust
which condenses in the chimneys of the zinc works of Goster contains oxide
iridium in the proportion ~th per cent. He gives the following directions
for its extraction. Boil the deposit for half an hour with hydrochloric acid,
and digest the clear liquid with pieces of zinc for six hours at the ordinary
temperature. There is then deposited a black metallic powder, which is
washed with water, and which contains copper, arsenic, cadmium, thallium,
and iridium. By boiling this with a concentrated solution of oxalic acid, a
solution of cadmium, thallium, and iridium is obtained ; the latter is precipi-
tated by ammonia, and the precipitate is then boiled with ammonia and
afterwards with water, until the washings contain no more thallium. The
oxide of iridium is then almost pure, and only contains traces of iron. — Vide
Journal fiir praktische Chemie.

Motive Power in Mines. — M. Tresca made a recent communication on this
point to the Society of Encouragement. Works in mines require a motive
power, either sudden and discontinued or continuous and slow. In the first

B B 2

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POPULAR SCIENCE REVIEW.

case, the best motor is compressed air ; in the second, water under pressure.
As in tunnel work there can he no admission of fire, combustion, or the en-
gendering of steam. Compressed air has been happily employed by
M. Sommelier for the engines used by him in the tunnel of the Alps.
Water under pressure was employed by M. Perret in the works of the South
of France railways, to give a rotatory movement to the rings or circles of M.
Deschaux, armed with diamond points for cutting the hardest rocks. — Vide
Foreign Correspondence, Chemical News.

The Chatham Ballast-iron. — The Admiralty having at last perceived the
value of the ballast-iron and having determined on its sale, orders for several
thousands tons of this material have been already sent in. The examination
of the ballast-iron in use at Chatham dock -yard showed that there are four or
five different qualities, the best kind being very valuable. The quality of the
iron, however, can only be ascertained after each pig has been split asunder,
to allow of the crystals being seen ; and as the method in which the iron is
broken has been found to materially affect its quality, the duty of breaking
each of the pigs of the quantity of iron sold will be undertaken by Messrs.
Kyland, who will be paid at the rate of Is. 6d. per ton for this work, in
addition to their commission on the sales. The Admiralty order also directs
the sale of 2,000 tons of the ballast-iron in store at Sheerness Dockyard, on
the same conditions. The circumstance of the iron requiring to be broken
before it is sold will render the entire 4,000 tons useless as ballast-iron,
should the Admiralty terms not be accepted. It is worthy of remark that,
notwithstanding the comparatively high value of the ballast-iron, the
experience of the last few years has completely proved that in a dockyard
like Chatham, in which the traffic of enormous armour-plates, with the
heavy slabs, plates, and iron beams used in the construction of iron ships is
going on all at hours of the day, the granite tramways laid down require re-
newing and repairing at intervals of a few months; while, on the other
hand, the passage of the heavy weights has no perceptible effect upon those
portions of the yard where the tramways are laid with pigs of iron. — Vide
The Artizan , June.

MICROSCOPY.

Under this section we have little to record for the past quarter. Mr.
Stokes has written to the Microscopical Journal on the subject of u slides by
post,” and as the matter is of interest we shall give a short account of the
method he proposes to avoid breakage of slides when travelling through the
post office. He says, cut two narrow slips of card-board, and gum them
across the slide on each side of the cover, so as to prevent a slide or the side
of the box from touching the cover ; roll up four or five slides in paper, and
place them in one of the ordinary postal boxes. The box should be left
bare and an ordinary parchment label attached to it, by lacing a cord round
it. On this label the direction should be written and the stamp affixed.

New Objects for the Microscope. — Mr. Dancer has read a paper before the
Manchester Philosophical Society, in which he says that the coal ash from

SCIENTIFIC SUMMARY.

339

the flue of a furnace supplies some interesting objects for the Microscope.
Besides other bodies contained in this coal ash may be seen a number of
curious-looking objects which vary in size and colour. The majority of
these bodies are spherical, and when separated from the irregularly shaped
particles forming the bulk of the dust they become interesting objects for
the microscope. Some of these are as perfect in form as the most carefully
turned billiard balls, and have a brilliant polish. The various colours which
these globules exhibit give additional interest to their examination. Some
are transparent crystal spheres, others are opaque white, many are yellow
and brown, and variegated like polished agates or cornelian of different
shades. The most abundant of the highly polished balls are black ; there
are others which look like rusty cannon balls — some of these have an aper-
ture in them like a bombshell, and many are perforated in all directions. To
obtain these objects the dust should be washed in a bowl and all the lightest
particles allowed to float away; the remainder consists of fragmentary
crystalline and ferruginous substances ; mixed with these are the polished
balls described, which, under the microscope, by a brilliant reflected light,
look like little gems. To separate the spherical bodies from the irregular
ones, it is only necessary to sprinkle some of this material on an inclined
glass plate, and by gentle vibration the balls roll down, and can thus be
collected. — Vide Chemical News, June 21st.

PHOTOGRAPHY.

Photography at the Paris Exhibition. — On the whole, the art-science of
photography plays its part well at the great French International Exhibition,
and in the collective displays of various nations we find its numerous and
diverse applications, improvements, and modifications fairly represented.
The Austrian collection is a very attractive one and contains some of the
very best specimens of photo-lithography yet produced ; its specimens of
portraiture from life-size downward are of a very excellent character, and,
like those of France, Prussia, and Russia, are decidedly superior to the
English. In the Darmstadt contributions are some interesting specimens by
Dr. Reissiz exhibited to illustrate his theory of photogenic action. In the
Prussian department a large portrait lens attracts attention ; it is four-
teen inches in diameter and covers a square of thirty inches. The French
department contains some interesting specimens of photographic-engraving
process, of enamelled photographs, and of enlargements from microscopical
photographs, amongst which is one of a flea enlarged to the size of a small
pig. Amongst the novelties and applications of photography to decorative art
are photographs of a singular character, illustrative of a new process called
“ Chrysoplasty.” They represent goldsmiths’ work, ancient armour, draperies
embroidered with gold and silver, bronze statuary, philosophic instruments,
&c., and are apparently in the same metals as the originals. This process is
a secret one, but the inventor, Mr. Bceringer, is prepared to produce such
photographs from any negatives which may be sent him for that purpose.
He is at present making a large collection of specimens from antique curi-

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POPULAR SCIENCE REVIEW.

osities and works of art in metal dispersed in tlie public and private museums
of various nations, and with this end in view appeals to the owners and
guardians of such collections, and those who have negatives of the required
description, to render him assistance. In photographic portraiture, by uni-
versal consent, the French stand prominently foremost, so much so that as
the Times says u amongst those articles which are specially called articles
de Paris , a good photographic portrait is now to be placed.” In the English
department we miss most of our foremost photographers, amongst them Air.
0. Gr. Reglandes, Air. T. R. Williams, and but too many others. Air. Alayall,
AI. Claudet, Lock and Whitfield, Ross and other of our chief portraitists
exhibit largely, but all show but weak and mean when contrasted with
their rival portraitists as represented in the French collection. As landscapists
English photographers, like English painters, carry off the palm. Why
landscapes by English operators so far surpass others we cannot explain, but
no one with any artistic taste or j udgment, would hesitate to attribute the
superiority of the French portraits purely and simply to a more refined taste
and greater knowledge of pictorial science in their producers. The English
photographs display little merit beyond such as belongs exclusively to the
skilful management of good tools, while the French photographers are
evidently, as a rule, artists studying such things as lighting, posing and
arranging, exposing and developing with considerable artistic knowledge
and preconceived design, the former with a view to putting a picture before
the lens, and the latter with a view to its faithful reproduction in the
operating room. Two of the great secrets of their greater success will, we
believe, be found to reside in the much longer exposures they give their
plates in the camera and in the use of a developer not so rapid in its action
as to escape control during development. The great cry in England has
been* for short exposures and powerful developers, things which war against
the subtle delicacies of gradations from light to dark, and from darks into
reflected lights, which constitute one^ of the most special and striking pecu-
liarities of the best French portraits. Refer back to past volumes of the
English photographic journals and this craving for extraordinary rapidity
coupled with frequent mention of the extraordinary long exposures given
on the continent, where the light is more powerful and the atmosphere more
pure, will be found. You will also perceive that while articles tending
directly and indirectly to give mechanical manipulation and good tools all
the credit of increased success crowd their pages to a wearying degree of
sameness and repetition, papers of a truly art-educational character are
extremely rare, in consequence, we have been informed, of the little real
appreciation they meet with from English photographic students. Hence
probably the inartistic and tasteless character displayed by their photographs
when contrasted with those of our more artistic and tasteful neighbours.

The Due de Luynes Prize. — In 1859 the French Photographic Society distri-
buted the sum of 2,000 francs as prizes for the best researches in producing
unalterable photographs, and as part of the sum of 10,000 francs devoted to that
purpose by the Due de Luynes. The society then fixed upon the 1st of April,
1864, for the further award of the remaining sum. The decision of the
jury was however postponed and the decision announced on the 5th of last
April awarded the 8,000 francs to AI. Poitevin for his photo-lithographic
process published in 1855. According to this decision all the claims made

SCIENTIFIC SUMMARY.

341

by M. Poitevin’s rival competitors, Talbot, Niece de St. Victor, Lemercier,
Charles Negre, Placet, Woodbury, Pouncy, Paul Pretsch, Cole, James, and
others, have achieved nothing,* having greater pretensions to permanency
than a process extant in 1859 had. And yet good and truly permanent
photographs are almost as much a want of the age now as they have been
since the art’s discovery, and all our best experimentalists are still hard at
work in this identical direction.

Preservation of Photographs. — In a paper read before the Glasgow Photo-
graphic Association on the 11th of April, Mr. J. Stuart recommended the
saturation of prints with collodion as a means of ensuring their permanency.
Since then others have strongly recommended this process as a very valuable
one, well calculated to effect the desired end, and Mr. Valentine Blanchard
in a paper read before the London Photographic Society, gave the result of
some experiments in carrying out Mr. Stuart’s idea. On this occasion the
Rev. J. B. Reade, F.R.S., who occupied the chair, gave the entire credit of
the idea to Mr. Blanchard as others have done since, and said the process
really conferred immunity from fading. Mr. Belton, at the June meeting of
the North London Photographic Association, stated that it was best according
to his experience to apply the collodion to the prints somewhat sparingly, both
before and behind, with a brush, and to immerse them in hot water before
mounting, so as to render them more plastic. He had used starch for
mounting, but thought good glue would prove the better material.

The Collodio- Albumen Process. — Mr. Maxwell Lyte, whose excellent
photographs have been so often and widely admired, and from whom we
have so frequently derived hints of great practical value, has introduced a
modification of the collodio-albumen process, by which it is said to be
rendered more sensitive. The iodides and bromides he employs are those of
sodium, and he does not advise the use of salts of cadmium. After sen-
sitising, the plates are washed and rewashed in a weak solution of salt to
remove the free nitrate of silver. The albumen is prepared by an ammo-
niacal solution of chloride of silver, and the plate allowed to dry over a
capsule of sulphuric acid, in order to absorb all the free ammonia. The
developer is a solution of protosulphate of iron without acid. The albumen
used should not be thick, and all the ammonia should have evaporated
before exposure.

Photographs in Colours. — M. ‘Poitevin’s photographs in natural colours,
described in these pages, were recently stated by that gentleman to fade
even in the dark.

Oxalic Acid in the Negative Bath. — An editorial article in the u British
J ournal of Photography,” speaks of the presence of pin-holes in the film and
insensitive streaks on its surface as frequently due to the presence of
crystals consisting of oxalate of silver. After explaining how oxalic acid
may be present in the collodion, the article attributes thereto the formation
of the above crystals, and says their nature may be readily proved by two
very simple tests. One is to heat over a spirit-lamp a few of the crystals
previously washed in a little water and then dried in a small tube closed at
one end, when if oxalate of silver they will detonate almost like a few grains
gunpowder, and the other is the placing of a few of the crystals in powder
on a watch glass, adding a little water with a drop of sulphide of ammonion.

342

POPULAR SCIENCE REVIEW.

If then stirred, and allowed to stand for an hour or so the black sulphide
of silver will be produced, and oxalate of ammonium contained in the
liquid. The latter is then filtered off into a test tube and boiled with the
addition of a drop or two of dilute acetic acid, and solution of sulphate of
lime added when the production of a white precipitate insoluble in acetic
but easily dissolved in nitric acid. This at once indicates the presence of
oxalic acid. The writer then gives as the best remedy with which he is
acquainted, the adding of a drop or two of solution of nitrate of lime to the
bath, when the precipitate can be removed by filtration. Any slight excess
of the nitrate of lime will not injure the bath.

The Bromized Collodion Process. — This process of Major Bussells is de-
scribed by the : editor of Photographic Notes , as 11 the first in point of
absolute merit ” of all the “ dry collodion processes ; ” and he continues,
“Nothing can surpass the beauty of its specimens produced by the Major
himself. We have never seen foliage in all its depths so admirably rendered
as in some of these specimens ; ” and moreover adds, that they are “the most
sensitive plates ever exposed in a camera up to the present time.” Knowing
these to be the opinions of a good practical and scientific photographer
we give our readers the process, which is briefly this : — “ The collodion
contains about 8 grns. of bromide of cadmium to the oz. and no iodide.
The plates are immersed for ten minutes to a quarter of an hour in a 70
grn. nitrate bath, acidified with nitric acid, and they are then washed
excessively .” This is a point of primary importance. The washed plate is
then coated with tannin, or some other suitable organic matter, and is
allowed to dry spontaneously. The exposure is the same as in the wet
process, and the development is effected by means of a solution of pyrogallic
acid, to which carbonate of ammonia is added. No subsequent intensifica-
tion is necessary, because any degree of density can be obtained by increasing
the proportion of carbonate of ammonia added to the solution. To retard
the action of the developer, which .would otherwise be too energetic, add
bromide of cadmium, which must be very nicely proportioned to the
quantity of alkali, a slight excess tending to enfeeble the image and too
little to produce fog. The exact balance can only be hit by frequent experi-
ment, and when attained, care should be taken always to preserve it. With
this additional care the process is one of exceeding value both as regards
the artistic value of its result and scientific accuracy of principle. We must
add that the plates do not keep so long after exposure as others do.

The Photographic Society. — The Photographic Times commenting on
the present unpromising position and gloomy prospects of the London
Photographic Society says, “ Only fancy an association having less than 300
members, and an income of as many pounds (if every member pays), paying
its secretary JloO per annum. This sum will seem the more inordinate
when it is considered that the society holds but eight meetings per annum,
and when it is considered that many competent men would be glad to hold
the post as an honorary, appointed for the mere love of an art which they
practise a3 a scientific recreation.

Photography in London. — The offlcial catalogue of the Paris Exhibition,
British department, gives the following statistical account of the number of
persons engaged in photographic trade in London, exclusively of workmen.

SCIENTIFIC SUMMARY.

343

Photographic artists," 284 ; apparatus makers, 38 ; album makers, 38 ;
chemists, 17 ; moimters, 6 ; paper makers, 15 ; publishers, 16 ; dealers in
materials, 28.

New Photo-Engraving Process. — The Chemical News asserts that a new
process of photo-engraving by M. Baldus is about to be introduced, far
surpassing in simplicity, certainty, and beauty of result, the best works
produced by Messrs. Woodbury, Swan, and others, and at a price fabu-
lously low. The process is a secret one but is said to be exceedingly
simple.

Long-kept Plates. — At a meeting of the Philadelphia Photographic Society
a member exhibited a print from a tannin negative which had been kept
five years previous to exposure, and a tannin negative developed one year
after exposure.

The Nature of the Latent Image. — Mr. Carey Lea has advanced what he
considers “ some entirely new views,” on the nature of the latent image : he
says : “When light considered in reference to its illuminating power falls upon
any surface, we are accustomed to regard the effect of that illumination as
passing away at the same instant of time that the illumination terminates.
But there are a vast number of well recognised exceptions to this rule which
we know under the name of phosphorescence and fluorescence,” which proves,
says Mr. Lea, “ that bodies may by light be thrown into a state of vibratory
motion, lasting for a longer or shorter, sometimes for a very considerable
time after the exciting cause is removed, and that, so long as this vibratory
movement continues they will themselves emit light.” The writer then
proceeds to argue that there is no reason to doubt the property we con-
veniently call actinism may have similar power on certain bodies and that the
latent image “ is simply a phosphorescence of actinic rays. . . Pure iodide
of silver undergoes no decomposition by light when thoroughly isolated from
all substances, organic and inorganic, which are capable of aiding in effecting
a reduction. But, if exposed to light, it continues for a certain time there-
after to retain the vibrations it received ; and just for so long as these vibra-
tions continue will it be instantly decomposed if brought into contact with any
substance which would have caused its decomposition had the two been subjected
to the action of light together. . . For this property of light I propose the
name of * Actinescence.’ The more we examine these phenomena the
more we shall perceive that actinescence must, so to speak, exist j for different
phosphorescent bodies emit light of very different colours, showing that their
respective capacities of prolonged impression are confined to rays of a certain
refrangibility, differing from each other in each case. Now we know that
the actinic influence accompanies rays of a certain refrangibility, especially
the violet, the indigo, and the rays immediately beyond the visible. The
permanence therefore of these actinic rays, under suitable circumstances is
no more difficult of conception than that of other rays, a fact which has
been known and recognised for centuries.” Mr. Lea then argues that the
faculty of receiving a latent developable impression depends on the posses-
sion of two properties, viz. sensitiveness to light, and actinescence ; that a body
may be actinescent without being sensitive to light, and therefore unable to
retain the latent image, and that on the other hand substances may be
merely sensitive to light when brought in contact with others, but which
not retaining the impressions made by light until the decomposing agent be

344

POPULAR SCIENCE REVIEW.

brought in contact -with them, are likewise incapable of receiving latent
images. But these capacities may exist conjointly, as we see in the case of
large numbers of silver compounds. This new theory rests upon these facts,
namely, the sensibility to light of pure iodide of silver and the spontaneous
resensilising of pure iodide of silver, and will, as Mr. Carey Lea believes,
(( dispel all the mystery that has seemed to some to envelope the idea of a
physical image and bring all the most obscure facts of photo-chemistry into
parallelism with well understood and very simple phenomena.” We quote
from the British Journal of Photography, in which, unless we are much
mistaken, similar views were put forth some time since.*

A New Camera has been introduced in America for producing simul-
taneously any number of portraits of a sitter with one lens. This is ob-
tained by the adjustment of a number of movable mirrors fastened on
blocks of wood and so contrived as to throw the reflected images each on the
proper part of the plate or focussing screen.

PHYSICS.

The Physics of Chemical Reaction. — According to the researches of M.
Berthelot, a chemical reaction, which is capable of setting free an appreciable
quantity of heat, will always accompany the following conditions : — 1. The
reaction is one which reaches its limit within a very short time from its
commencement ; this condition is fundamental. 2. The reaction is one
which begins without foreign aid at the temperature of the commencement
of the experiment ; reactions excluded by this condition act in conformity
with the principle enunciated if they are caused to set in either by raising
the temperature or by other means. 3. The parent substances and the
products possess similar functions. He is of opinion that the inverse re-
actions of iodhydric acid and argentic chloride might be foreseen from the
basis of this general principle, and that the analogous action of iodhydric
acid on potassic chloride, which he has experimentally verified, is a further
proof of the correctness of his view. — Vide Chemical Neivs.

A 11 Standard” Spectrum, which promises to be exceedingly useful, and

* Since the above was written, Mr. W. H. Harrison has written to the
paper in which Mr. Lea’s articles appear, expressing u unbounded astonish-
ment ” to find that gentleman republishing his ideas as new ones of his own,
without any alteration whatever, except a guess, unsupported by experiment,
11 that the moving molecules vibrate with a motion which throws off chemical
rays.” Both Mr. Lea and Mr. Harrison have long been constant contribu-
tors to the British Journal of Photography, in which the papers on u The
Mechanical Action of Light,” to which the latter gentleman alludes, were
published not longer ago than last autumn. Our own impression is that
these ideas were published long before either Mr. Lea or Mr. Harrison ad-
vanced them in Hunt’s (C Researches,” but between this and our next issue
we shall give the matter further attention.

SCIENTIFIC SUMMARY.

345

seems likely to be conducive to discovery in this department of physics, has
been devised by Mr. H. C. Sorby. Mr. Sorby proposes that it shall be used
as a scale in all descriptions of spectra as seen by the micro-spectroscope.
The following is Mr. Sorby’ s description of the new scale. It is an inter-
ference spectrum, produced by a plate of quartz -043 inch thick, cut parallel
to the principal axis of the crystal, and placed between two Nicol’s prisms.
In this the whole visible space is divided by dark bands into twelve regular
divisions, having in all parts the same relation to the physical properties of
the light. These are counted from the red end towards the blue, their
centres being reckoned as 1, 2, 3, &c. and the thickness of the plate is so
adjusted that the sodium line exactly corresponds to 3 a. The intensity of
the absorption is expressed by the following types : —

Not at all shaded
Very slightly shaded
Decidedly shaded
More shaded

Strongly shaded, but so
that a trace of colour is
still seen
Still darker
Nearly black

Blank space

. . Dots trith wide spaces
. . . Dots closer together
. . . Very close dots

Three hyphens close

— Single dash
Double dash

Except when specially requisite, only the symbols . . . — — are
employed for the sake of simplicity, and then as signs of the relative rather
than of the absolute amount of absorption, and it is assumed that there
is a gradual shading off from one tint to the other, unless the contrary is
expressed. — Chemical New s, May 3.

The Contractions and Dilatations of Iodide of Silver. — At a meeting of the
French Academy on April 15, M. Fizeau returned to this subject. He
found that with iodide of silver, whether in its amorphous or crystalline
state, the action of heat established by him is reversed ; its dilatation is
negative, contracting instead of expanding on the increase of temperature.
But this negative dilatation is not quite the same in the amorphous state,
in the state of compressed precipitate, as in the crystalline state ;
— 000000137 in the first case, —0-00000139 in the second.

The Determination of the Density of Ozone. — A note on this subject was com-
municated to the Academy of Science by Mr. Soret, of Geneva. Experi-
ments by means of absorption lead to the conclusion that the density of ozone is
one and a half times that of oxygen. lie applied Graham’s law of diffusion
— viz. that the diffusion takes place in the inverse proportion of the square
of the density. He then diffused two mixtures — one of oxygen and chlorine ;
the other of oxygen and ozone. Thus compared, the density of ozone to
that of chlorine or oxygen was found to be 1 : 5.

Development of Ozone during the present year. — A correspondent of the
Chemical News gives an acconnt of the development of ozone since the first of
January. In January there were two well-marked periods of scarcely a
trace of ozone — namely, from the 1st to the 5th, culminating on the 4th,
when the test was colourless, and from the 10th to the 19th, culminating
on the 13th, 14th, and 18th. Both these periods were followed by

346

POPULAE SCIENCE EEYIEW.

equally well-marked periods of a large development of ozone. In February
no such well-marked and settled periods occurred. On some days there was
but little ozone, as, for instance, on the 2nd, and the afternoons of tbe 21st
and 28th, especially on the afternoon of the 21st ; while on other days
there was a good deal, as on the 16th, 18th, and 20th. But the periods of
increased and decreased development were short and unsettled, often lasting
not more than a few hours, and at most a day or two. In March there was
scarcely a trace of ozone on the 1st and 2nd, and very little on the 3rd, 8th,
9th, and 16th ; considerable quantities on the 13th, 25th, 27th, and 30th,
especially on the 25th and 30th. Speaking generally, there was a period of
scanty development of ozone till the middle of the month, and then a period
of more plentiful development towards the end ; but neither of these periods
was well defined or settled. — Vide Chemical News, April 19.

The Measurement of the Magnetic Dip. — A paper was lately read before the
Manchester Philosophical Society by Sir William Thomson, on a new form of
the dynamic method for measuring the magnetic dip. Seven years ago, an
apparatus was constructed for the natural philosophy class of the University
of Glasgow, for illustrating the induction of electric currents by the motion
of a conductor across the lines of terrestrial magnetic force. This instru-
ment consisted of a large circular coil of many turns of fine copper wire,
made to rotate by wheelwork about an axis, which can be set to positions
inclined at all angles to the vertical. A fixed circle, parallel to the plane
containing these positions, measured the angles between them. The ends
of the coil were connected with fixed electrodes, so adjusted as to reverse
the connections every time the plane of the coil passed through the position
perpendicular to that plane. When in use, the instrument should be set as
nearly as may be in the magnetic meridian. The fixed electrodes being
joined to the two ends of a coil of a delicate galvanometer, a large deflection
is observed when the axis of rotation forms any considerable angle with the
line of magnetic dip. On first trying the instrument, Sir William perceived
that its sensibility was such as to promise an extremely sensitive means for
measuring the dip. Accordingly, soon after he had a small and more port-
able instrument constructed for this special purpose ; but up to this time he
had not given it any sufficient trial. On the occasion of a recent visit, Dr.
Joule assisted at some experiments with this instrument. The results have
convinced both observers that it will be quite practicable to improve it so
that it may serve for a determination of the dip within a minute of angle.

The Movement of Solids under Pressure. — M. Tresca, whose fine researches
we have before noticed in these pages, has presented a second part of his
memoirs to the Academy. This portion of his memoirs relates to the flowing
of solids through simple or multiple circular, polygonal, and lateral orifices,
and described a great number of interesting particulars which confirm
the results of his former experiments, and undoubtedly prove that the mole-
cules of substances of the stiffest nature in appearance possess the property
of moving independently, generally in parallel directions. The flowing takes
place in concentric zones. — Vide Comptes Rcndus, April 22.

The Pei'iodical Variations of Tempei'ature. — M. St. Claire Deville has
been publishing a second series of his investigations in the above interesting
meteorological subject. He has established, in one of his former memoirs,

SCIENTIFIC SUMMARY.

347

that there exists a certain depending connection in the movement of the
mean temperature of four days, placed on the ecliptic at an angle of 90° one
from the other, for the four months (opposed two by two) of February, May,
August, and November, which contain the critical days, known by the
ancients under the name of the three saints of ice (May 11, 12, 13), and the
summer of Saint Martin (November 11). In this new work he shows that
the fact is general, and that this connection or mutual dependence of the
four opposite days exists during the whole of the year ; whether we take
into consideration a considerable cycle — 110 years at Berlin, 90 years at
Vienna, 50 at London, 40 at Prague and Edinburgh, 30 at Brussels, 24 at
Toulouse, 21 at Paris — or that we take in this point of view an isolated year
(1864) on several European stations. The former, depending upon the same
data, establishes, in fine, that this connection is evident also when we com-
bine twelve by twelve the days separated one from the other by 30° of the
ecliptic. The latter phenomenon constitutes the meteorological month , as the
season was established by the consideration of the quadruple days.

Alteration of the Freezing-point in Thermometers. — Dr. J. P. Fowler,
F.B.S., has recorded an important fact in connection with the alteration of
the freezing-point in thermometers which have been for some time in use.
Having had in his possession, and in frequent use, for nearly a quarter of a
century, two thermometers, of which he has from time to time taken the
freezing-points, he thinks the results of some interest. Both thermometers
are graduated on the stem, and are, he believes, the first in this country
which were accurately calibrated. Thirteen divisions of one of them cor-
respond to one degree Fahrenheit. It was made by Mr. Dancer in the
winter of 1843-44. His first observation of its freezing-point was made
in April 1844. Calling this zero, his successive observations have given

0 April 1844.

5' 5 February 1846.

6'6 January 1848.

6-9 April 1848.

8- 8 February 1853.

9- 5 April 1856.

11T December 1860.

11-8 March 1867.

The total rise has been, therefore, -91 of a degree Fahrenheit. The other
thermometer is not so sensitive, having less than four divisions to the degree.
The total rise of its freezing-point has been only *6 of a degree ; but this is
probably owing to the time which elapsed between its construction and the
first observation being rather greater than in the case of the other thermo-
meter. The rise of the two thermometers has been almost identical during
the last nineteen years.

Crystalline Refraction. — M. A. Cornu has written a memoir on this sub-
ject, in which he propounds a new theory of Fresnel’s law of crystalline
refraction. The principal conclusions of the report in his memoir were, that
the luminous vibrations were normal to the plane of polarisation, as Fresnel
and Cauchy announced a long time ago, though the direct proofs hitherto
proposed are open to discussion.

348

POPULAR SCIENCE REVIEW.

How to Drill Glass. — An ingenious method of drilling glass, which was first
described in Hardwicke’s Science Gossip and quoted by the Chemical Neivs ,
has elicited from Dr. Lunge an account of another means which he has
found extremely simple and efficient. It is simply the employment of dilute
sulphuric acid — and he found it, on trial, to answer much better than the
method referred to. Not only, it appears, is the efficacy of the cutting tool more
increased by sulphuric acid than by oil of turpentine, but also, strange as it
seems, the tools (files, drills, &c.) are far less rapidly destroyed by being used
with the acid than with the oil. He also found it stated that, in the
engineering establishment of Mr. Pintus, at Berlin, glass castings for pump
barrels, &c., were drilled, planed, and bored, just like iron ones, and in the
same lathes and machines, by the aid of sulphuric acid. As to drilling, Dr.
Lunge can fully testify to the efficacy of that method. Whenever he wants,
say, a hole in the side of a bottle, he sends it, along with some dilute (1 : 5)
sulphuric acid, to the blacksmith, who drills in it, with a hand-brace, a hole
of ^-inch diameter. This hole is then widened to the required size by means
of a triangular or round file, again wetted with the acid. He also finds a
great help in the latter when making graduations on litre flasks, &c. There
is hardly any smell perceptible during the work, which proves how little the
acid acts upon the tools, undoubtedly owing to their being tempered ; but
each time after use, he takes the precaution to wash and dry the files at once,
and he has so far observed no sensible deterioration in them.

~ Transparency of Metals at a bright Red Heat. — Dr. Adriani has written a
letter to a contemporary relative to the reported discovery of Father Secchi,
that metals at a red heat are transparent. He states that the fact that iron,
steel, and also platinum and copper, are transparent while at a bright red
heat, has been known long since not only to practical engineers, but, as re-
gards iron, steel, copper, and platinum, to workers in these metals. The
account given of the manner in which M. Secchi found out this property of
iron is as follows : — The reverend Father hadjordered a strong iron tube to
be made. As it was intended for an apparatus requiring a vacuum, it was
essential that this tube should be perfectly airtight : and as Father Secchi
had some doubts about its soundness in this respect, in order to set these at
rest, the tube was made red-hot and taken into a dark place, when he
clearly perceived through the iron, which was half a centimetre thick,
a crack inside the tube, and which did not reach to the outer surface.
It is rather curious that the fact of the metals above alluded to (to which
Dr. Adriani says he has reason to believe that gold may be added) becoming-
transparent at red heat should have escaped the notice of scientific men.
It requires, however, a good bright red heat ; but the transparency of the
metals is, he says, evident thus even in daylight, as he knows from his own
experience, while working many years ago in an engineering establishment
attached to a large sugar refinery.

The Bisulphide of Carbon in Coal-gas. — The valuable researches which
have just been published by Professor Alfred Gr. Anderson, demonstrate
beyond all question the imperfection of the apparatus at present employed
in the estimation of bisulphide of carbon in coal-gas. We cannot here
enter into details of this chemist’s enquiries, but we may state that they
support two conclusions, which are thus stated by the author .- — 1. That in

SCIENTIFIC SUMMARY.

349

determining the sulphur of coal-gas, the a single ” (fish-tail) burner, caused
to consume the gas at the rate of cubic feet in five to six hours, effects
its combustion most completely. That even under these circumstances 2 per
cent, of its sulphur cannot be burned into sulphurous acid. 2. That in no
case can the sulphurous products of the combustion be wholly recovered
where condensing receivers open to the external atmosphere are employed.
The best arrangement of apparatus set up on this principle loses 40 per
cent, of sulphur. And the arrangement given by Dr. Letheby, I find, from
the same cause, always entails a loss varying from three-fourths to four -
fifths of the bisulphide sulphur of the gas.

Professor Anderson has already given evidence upon the subject of coal-
gas before various Committees of the House of Commons, and we trust that,
in the event of the passing of the new Act, the Government will select men
of his practical experience for the proposed offices of Inspectors.

ZOOLOGY AND COMPAEATIVE ANATOMY.

The Australian Timber-boring Insect , Tomicus monographus. — The last-named
species which is stated to be new to Australia, has, we believe, been recently
introduced into that country. It is a most destructive creature, which seems
to prey on casks and barrels with a voracity almost unequalled in the class
to which it belongs. The T. typographic, a species more familiar to ento-
mologists, is said to have destroyed no less than a million and a half of pines
in the Hartz forest in the year 1783. An Australian paper gives the follow-
ing description of this species, and of its ravages among the casks in some of
the local breweries : — The proboscis forms an excellent gimlet, with which
the little insect penetrates the hardest wood in an incredibly short time,
while the hinder portion is shaped like a shovel, and is employed in getting
rid of the sawdust. They make clean holes through the staves ; and some
of the full barrels are leaking in fifty places. In a wine-cellar, thousands
burrow into the wine and spirit casks. As soon as they get nearly through
the wood, the liquor begins to ooze out, and the animal, of course, gets
killed. Every description of box or barrel is full of them, also the doors and
timber in the building. Almost every store in the township is infested with
these mischievous insects. The head is red, with a proboscis somewhat
resembling a parrot’s bill ; and the body is like a small black glass bugle
broken off at the end ; the whole length, one quarter of an inch.

The silk-worm disease has this year shown itself at Grenoble, under a new
form, and is doing extensive damage. According to the reports, the worm
does not present any of the symptoms such as blackish spots, noticed in
former years, but when it has arrived at the third change, it cannot go any
further, and dies of exhaustion. This is attributed to the yellowish leaves
of the mulberry, which do not furnish sufficient nourishment. The evil has
not been so great in fact in the Ardeche or the Gard, where the weather has
been less rainy. Too much rain, it is known, proves injurious to the nutritive
qualities of the mulberry leaf.

The Crested Agouti, — Mr. St. George Mivart, of St. Mary’s Hospital, has

350

POPULAR SCIENCE REVIEW.

reprinted his fine monograph upon the Crested Agouti. His investigation of
the Dasyprocta cristcita was conducted jointly with Dr. J. Murie, of the
Zoological Society, and the facts arrived at may be thus briefly stated : (1)
The unconstricted condition of the stomach of D. cristata, as compared with
that of D. aguti j (2) the tendency towards a double apex of the heart ; (3)
the approximation of the ureters to the fundus of the bladder,- (4) the presence
of a superficial long femoral artery. As regards the comparison between the
crested Agouti, guinea-pig, hare and rabbit, Messrs. Mivart and Murie find
that the first differs from all the others and stands alone in the following
particulars : (1) The number and arrangement of the pads of the pes and
manus; (2) the greater extension of the levator clavicuke,- (3) the absence of
the rhomboideus capitis muscle : 5, 6, 7, 8, 9, and 10, refer to peculiarities
of other muscles, which we fear are unfamiliar to our readers.

The Osteology of the Insectivora has also been very carefully studied by
Mr. Mivart, but as the memoir in which his observations on this subject are
stated appears in the May number of the Journal of Anatomy , we must refer
our readers to that periodical for the particulars.

The Movement of Flight in Birds , fyc., is the subject of a paper read in
June last before the Linnean Society by Dr. J. B. Pettigrew. After pointing
out the nature of the various forms of locomotion in animals, and showing
the relation between the surface moved upon and the organs of locomotion,
Dr. Pettigrew states that the body, or parts of the body, in all animals are
presented and withdrawn from the several media by rotatory and spiral
movements. These movements are for the most part produced by a judicious
combination of ball-and-socket and hinge joints, the former occurring as a
rule at the shoulder or pelvis, the latter in the limbs when present. The
spiral movements are least perceptible in the extremities of land animals,
but a careful examination, of the structure of the joints, particularly the
elbow and knee joints, and of their movements, will convince even a casual
observer of their presence. They are more marked in animals which swim,
the sea-bear twisting its flappers about with incredible dexterity, so as to
present them obliquely to the water the one instant, and non-obliquely, or
with their thin edge, the next. The same happens in the lower portions of
the body in the seal and fish, the latter applying its tail to the water very
much as an oar in sculling. The rotatory and twisting movements are
still more perceptible in the application of wings, the pinions of the
insect, bat, and bird being for this purpose twisted upon themselves. Dr.
Pettigrew attaches considerable importance to this circumstance, and shows
that but for the spiral conformation of the wing, and the fact of its
being rotated on and off the wind during extension and flexion, the air could
not be rendered subservient to the purposes of flight. He further shows that
the more the wing is twisted, and the greater the number of its oscillations,
the greater is its elevating and sustaining power. It would, therefore, seem
that the screw, or a modification of it, enters into the structure of the bodies
and extremities of all vertebrates, and that these are presented to the land,
the water, and the air by spiral movements whicn remarkably resemble each
other. Dr. Pettigrew’s paper is illustrated by upwards of 70 original draw-
ings, a large proportion of the figures being from living animals.

Blood Corpuscles of the Two-toed Sloth. — Professor Jtolleston lately tested

SCIENTIFIC SUMMARY.

351

the accuracy of Kiihne’s assertion that the sloth contains nucleated blood
corpuscles ; and the result of his observations has been the disproval of the
German physiologist’s assertion. The specimen examined was placed at
Professor Rolleston’s disposal by Mr. H. N. Moseley, of Exeter College, and
was carefully examined under the microscope. Professor Rolleston states
that the employment of a twelfth-of-an-inch 'object-glass by Messrs.
Powell & Lealand has convinced Mr. Moseley and himself that, though a
certain number of the dried blood-corpuscles of the sloth do contain one or
more nuclei more or less roughly hewn, and irregularly and eccentrically
placed, still the immense majority of them possess the non -nucleated
character ordinarily assigned to the mammalian red blood-cell. The large
size of the blood-cells of the two-toed sloth, the largest next to those of the
elephant put on record amongst mammalian blood-cells by Mr. Gulliver,
may, in more ways than one, have rendered an examination of them by a
low power amenable to fallacy, and recourse to those of a higher power
necessary. In the smaller corpuscles of the camel neither power enabled the
observer to detect the presence of nuclei in the coloured blood-cells.” —
Vide Quarterly Journal of Microscopical Science , April.

Gregarine Parasites in JBorlasia. — A paper was read some time since before
the Royal Microscopical Society of London by Dr. W. C. McIntosh on the
above subject. The author describes the parasite in general terms, and gives
a more minute account of certain ova which accompany the gregarinaform
body and are often extruded from the posterior end of the Borlasia under
pressure. These ova measured about jJ-^th of an inch in diameter, and each
contained an embryo that, for some time after the extrusion of the egg, made
very evident movements. They have two coats, an inner, faintly (concen-
trically) striated under pressure, and an external, without markings. The
contained embryo is finely granular, and has a large pale nucleus ; its various
postures may be distinctly seen. When an ovum is ruptured between the
glasses the contents spread abroad as a vast number of dancing granules.

A new species of (Ecistes has been discovered and described by Mr. Henry
Davis, who has made some curious experiments upon certain specimens.
These experiments appear to demonstrate that in the species which he terms
CE. intermedins the ciliated “chin” is employed in manufacturing tire tube
which the animal inhabits. In proof of this belief Mr. Davis says that he has
on several occasions noticed minute particles in suspension in the water drawn
across and from the buccal aperture and directed by the cilia over the chin
into a slight depression beneath it. The granules were not rotated nor
formed into pellets, but they simply collected in a spot agreeing with the
position of the pellet-cup in Melicerta. There was evidently a viscid
excretion at the spot which held the extraneous matters loosely together in
a clot; in about half a minute the rotifer would jerk down, leave the
floccose deposit on the edge of its case, then rise immediately and repeat the
process. On mixing a little carmine with the water, the process became
very striking ; an irregular crimson edge to the tube was made under Mr.
Davis’ observation, and, oil leaving a number of specimens of both species
in a zoophyte trough, charged with carmine, for forty-eight hours, he found
that a few had continued building, and made red tops of different sizes to
their habitations ; nearly one fourth of the entire structure in two instances
YOL. YI. — NO. XXIY. C C

352

POPULAR SCIENCE REVIEW.

was composed of the mixture of the red atoms and gelatinous excretion.
One. infant rotifer/ whose first efforts at building he had distinctly marked,
seemed to have made his entire nest of the glowing pigment. — Vide
Transactions of the Microscopical Society, No. 26.

A curious larva has been described to the Dublin Microscopical Club, by
Mr. John Barker. It was found in boggy ground in the Co. Wicklow. As we
have ourselves met this interesting form in large colonies, in some of the
Irish bogs we give the description of it for our entomological readers. The
larva was in great part enveloped in a compressed quadrangular case, expand-
ing towards the posterior end, elliptic in section j the aperture elliptic,
semi- trumpet-shaped, everted and a little flattened. Through this the
larva protruded its head and three pair of legs, which were long and, with
the exception of the first pair, which were short and ended in a forceps,
were armed with long and slightly curved unequal hooks. By means of
its legs the creature crawled along the bottom and sides of the vessel,
carrying the case swinging obliquely above. The two valve -like sides of
the case approximated towards the base, so as to present a slit ; it seemed
composed of structureless chitine, with a few hairs on its surface. It was
about in length, and I*/' broad at the base. The larva, after it had been
in confinement about a fortnight, anchored itself . by a sort of byssus to the
sides of the vessel. First, a mucous substance was deposited on the glass at
four different points ; then four sets of cords (about fifty in each) united
these attachments, two to the long axis of the mouth of the case, and two to
the angles of the base. The animal lay much shortened, with its head
curved round, its legs close together, entirely within the case.

The animal nature of sponges is demonstrated very clearly in a paper by
Prof. H. J. Clark, in a late number of Silliman’s American Journal. The
American naturalist considers that the ciliated sponges are most closely
allied to the monociliate Infusoria flag ellata.

How to observe the reproduction of Zoophytes. — Dr. T. Strethill Wright, in
a paper on u British Zoophytes,” gives some valuable advice to those who
wish to study the mode of reproduction of zoophytes. His remarks have
especial reference to the Naked-eyed Medusce. He says that the greatest
care must be taken that the sea- water used in the experiment is perfectly
free from the presence of the planuloid larvae of other forms, which are
frequently contained in water recently brought from the sea. The water
must be slowly passed through filtering paper into a glass vessel capable of
containing not less than three or four gallons, in which are placed a few
fronds of Chondrus crispus or Enteromorpha. A few of the medusae only should
be placed in the vessel, amongst which it is advisable, but not necessary, that
one should be a male with white and opaque, not transparent, spermatic sacs.
The animals should be frequently fed with minute pieces of mussel or oyster.
As soon as the planulae appear they should be removed with a dipping-
tube into a round glass shade inverted and filled with sea-water from the
larger vessel, to which a few drops of mussel-juice must be added daily until
it appears crowded with minute protozoa to serve as food for the future
hydroids. The internal surface of the shade, and the surface of the water,
should be examined often from without with an inch lens, and as soon as
each planula adheres to the inside of the glass, a thin disc of microscopic

SCIENTIFIC SUMMARY.

353

glass should be attached externally over its site with an interposed drop of
glycerine, to ensure a flat surface, and the microscope, placed on a proper
support, should be brought up to it armed with a power of about eighty
diameters. The light, the quantity of which must be regulated by a
diaphragm of blackened card or metal, should be reflected from a plane
mirror, and carefully adjusted so as to pass through the water directly in the
axis of the tube of the microscope. By this means the whole development
of the planula into the hydroid zoophyte, with the successive development
of the polypary, and the budding of the polyps, may be seen in a very
beautiful manner. — Vide Journal of Anatomy , No. ii.

Newspaper Zoology. — The ’ Pall Mall Gazette has published the fol-
lowing interesting note : — u The Courier de Saigon reports some extraordinary
items of natural history from the land of the Anamites. There is a certain
fish, called Ca-ong in the language of the country, which has distinguished
itself to that degree that the King has bestowed upon it the proud title of
“ Nam hai dui bnong gnan,” which, as everybody knows, means u Great
General of the South Sea.” It appears that this laudable fish is in the habit
of quietly paddling round the ships near the coast until somebody tumbles
overboard. He then seizes him instantly, and, instead of eating him,
gently carries him in his mouth to the shore. At Wung-tau, near St.
James’s Cape, they keep a skeleton of this extraordinary philanthropist. It
is about thirty-five feet long, possesses front teeth like an elephant, very
large eyes, a black skin very smooth, a tail like a lobster, and two wings on
the back.”

The Salmon in Australia. — There can be no longer any doubt of the
success of the experiment in introducing the Salmon into Australia. The
eggs were hatched, and the young were turned into the sea. From the sea
they have returned, and are mounting the River Derwent. So states a recent
letter from Dr. Officer, of Hobart Town. This is a great fact for fish-
hatchers. Pisciculture is no longer a science simply, it is an useful art.

Inffen "West ad.nat.3el .& sc .

WWQst imp.

Plate RVTI

Microscopic Stracttire of Rocks.

355

THE MICROSCOPE IN OEOLOOY.
By DAVID FORBES, F.R.S.

THE more searching and exact method of investigation now
demanded by the advancing state of geological enquiry, neces-
sitates that the student of that science shall in his researches
avail himself of all possible means which the collateral sciences
place at his disposal, and, amongst others, of those which can
enable him to extend his powers of observation beyond the
limits to which his unassisted eyesight can convey him.

As long as he encounters in the field only rocks of so coarse or
simple a structure as to admit of their being resolved by the naked
eye into their constituent mineral species, or of distinguishing
the fragments of previously existing rocks, of which they may
have been built up, he may speculate with a fair chance of suc-
cess as to their probable origin or mode of formation. When,
however, as is more often the rule than the exception, rocks
are everywhere met with presenting so fine-grained and appa-
rently homogeneous a texture as to defy such attempts at ocular
analysis, all speculations as to their nature and formation based
merely upon observation in the field, can but be compared to
groping in the dark, with the faint hope of stumbling upon the
truth.

In these cases the geologist must call in the aid of chemistry
and the microscope ; by chemical analysis he learns the per-
centage composition of the rock in question, and the microscopic
examination informs him how the chemical elements are mine-
ralogically combined, and at the same time affords valuable
information as to the physical structure and arrangement of the
components of the rock mass, tending to elucidate its formation
and origin.

The microscope, employed some thirty years back by Ehren-
berg in the examination of minute fossil organisms, is now
recognised as having already done good service to palaeontology,
but was quite unknown to the geologist proper until within the
last few years, when the admirable labours of Sorby have
demonstrated the importance of the microscope as an indispen-
VOL. VI. — NO. XXV. D D

356

POPULAR SCIENCE REVIEW.

sable instrument of research in the study of physical geology
and petrology, as well as indicated how much more may be
expected from its more extended application.

The application of the microscope in these enquiries is as yet,
however, quite in its infancy, for with the exception of Sorby’s
invaluable memoirs on some special points of enquiry, literally
nothing has as yet been made public which could even serve as
an introductory guide to the geologist who might wish to com-
mence the study of the subject. It is therefore with great hesi-
tation, and only after much solicitation, that the author of these
remarks has now ventured into print, with the hope that by once
breaking the ice, others more capable than himself may be
induced to communicate the results of their researches on the
same subject.*

In the present communication it is not intended to go into
the details of any special microscopic investigation, but, as far as
the space at disposal will allow, to attempt a short sketch of
some of the results already obtained, in order thereby to illus-
trate the use of the microscope in similar enquiries, and to place
the same before our readers in as plain and untechnical language
as possible.

When applying the microscope to the examination of rock
structure and composition, it is necessary to prepare the speci-
mens previously, in order to be enabled to make full use of
transmitted light in their investigation, since a mere inspection
of their outer surface, viewed as an opaque object, although
sometimes of considerable value, does not, however, give a tithe
of the information which their examination by transmitted
light will afford.

When in sufficiently thin splinters or laminae, by far the larger
proportion of mineral compounds allow light to pass through them
with more or less facility, and amongst these, most silicates,
chlorides, fluorides, carbonates, sulphates, borates, and other
salts, as well as many oxides, and some few sulphides, sulph-
arsenides, &c. On the other hand, all native metals, alloys, and
most of their combinations with sulphur, arsenic, antimony, &c.,
along with some few oxides and other compounds, are opaque,
even when in the thinnest laminse, and consequently when pre-
sent, as they often are, in minute quantity in rocks, although
sometimes recognisable by their external crystalline form, are

* In 1852 the author commenced the study of the microscopic structure
of rocks and minerals by means of sections prepared by Ochatz of Berlin,
but soon after commenced the preparation of the sections himself, in which
he was under many obligations to the kind aid and advice of Mr. Sorby.
At present his collection of sections of rocks, and their constituent minerals,
amounts to above two thousand, and represents a wide geographical dis-
tribution.

357

%

THE MICROSCOPE IN GEOLOGY.

not to be distinguished by their optical properties, as in the case
of those bodies which, as before mentioned, are translucent.

When a mineral or rock under examination is entirely in the
vitreous state, as, for example, obsidian, it appears when viewed
under the microscope, merely as' a more or less transparent or
coloured glass, presenting, if perfectly in the vitreous condition,
no evidence of crystalline or other structure, except perhaps
traces of the strise of viscid fusion. It is usually found on
inspection, however, that some part of the mass is sufficiently
de vitrified to allow of its structure and mineral composition
being recognised. In some cases, when the glassy appearance
presented to the eye would discourage any hopes of structure
being discovered, the microscope proved the reverse most con-
clusively ; as, for example, the section of glassy pitchstone from
Arran, shown in PI. XVII. fig. 4, in which the pyroxenic and
felspathic constituents of the rock are beautifully apparent, not-
withstanding that the rock itself looks like so much dirty green
bottle glass.

In many cases, however, where the specimens are so perfectly
in the vitreous state as to show no trace of structure whatsoever,
this may be developed by carefully acting upon the surface by
gaseous or liquid hydrofluoric acid.

The rock sections may be prepared for the microscope as fol-
lows : a fragment, from one-quarter to three-quarters of an inch
square, and of convenient thickness, is chipped off the rock
specimen in the direction of the required section, and ground
down upon an iron or pewter plate in a lapidary’s lathe with
emery, until a perfectly flat surface is obtained. This surface is
then worked down still finer by hand on a slab of black marble,
with less coarse emery, then upon a Water of Ayr stone with
water alone, and, lastly, finished by hand with water on a
slab of black marble. By these means the surface acquires a
sufficient polish without being contaminated with rouge or other
polishing powder or oil, as is sometimes the case with purchased
sections of rocks. This side of the rock is now cemented by
Canada balsam on to a small piece of plate glass about 1^- inch
square and J- thick, which serves as a handle when grinding the
other side on the emery plate as before ; this grinding is con-
tinued until the section is so thin as to be in danger of breaking
up from the roughness of the motion, upon which it is com-
pleted, by further grinding with emery by hand on marble,
and finished first upon Water of Ayr stone with water, and after-
wards upon black marble, as before described. The section is
now removed from the plate-glass, and mounted in Canada
balsam on a slide, covering its upper surface with a thin glass
as usual.

The thickness to which such sections need be reduced is, of

D D 2

358

POPULAR SCIENCE REVIEW.

course, entirely dependent upon the transparency of the rock
constituents, and is commonly from to of an inch.

Thin splinters of rocks and powdered fragments, mounted in
Canada balsam, may also be examined with advantage, but can-
not replace the above-described sections.

The examination of such a rock section enables a mineralogi-
cal analvsis to be made, even of the most compact and apparently
homogeneous rock, and generally leads to the discovery of other
mineral constituents previously unsuspected, from their being
invisible to the eye, and also, as Sorby has observed, allows
those minerals, formed at the time of solidification of the rock,
to be distinguished from such as are the products of subsequent
alteration.

Arranging rock species according to their structure, it will be
found that most rocks fall naturally into one or other of two
great classes —

I. Primary or Eruptive Rocks ;

II. Secondary or Sedimentary Rocks;

and it will be seen that the microscope is of special value when
applied in cases where the external appearance renders it
doubtful as to which of these classes a rock may pertain.

The terms 'primary and secondary are here used quite inde-
pendently of geological chronology. Primary rocks (of all ages)
might be called “ingenite or subnate rocks” (i.e. such as are
born, bred, or created within or below),* whilst the term “ derivate
rocks ” would be appropriate for the latter, since directly or
indirectly they are all derived from the destruction of the
former.

I. Primary or Eruptive Rocks.

This class includes rocks which have made their appearance
in many, if not in all epochs, from the most ancient to the most
recent, from the old granitic outbursts to the eruptions of the
now active volcanoes; and if, as is now generally admitted, the
earth be regarded as having been once a molten sphere, the
consolidated original crust of the globe would pertain to this
class of rocks.

Mineralogically they consist of crystallised silicates, with or
without free quartz, and usually containing many other minerals
in minor quantities, especially metallic compounds, as magnetite,

* These rocks are indiscriminately called volcanic, igneous, plutonic, cry-
stalline, &c. The term crystalline, although characteristic of these rocks,
is not exclusively so, and is consequently less appropriate ; many normal
sedimentary beds, as rocksalt, gypsum, &c., are perfectly crystalline, and
others when altered by metamorphic action, become more or less so.

THE MICROSCOPE IN GEOLOGY.

359

titanoferrite, iron pyrites, &c., which last are frequently present
in so minute a quantity as only to be detected by the microscope.

Whatever be their geological age, or from whatever part of
the earth’s surface they be taken, the microscopical inspection
of such rocks shows immediately that they possess certain
general and definite structural characters, distinguishing them
at once from all other rocks.

The mineral constituents of such rocks are seen to be de-
veloped as more or less perfect crystals, at all angles to one
another, thereby indicating that the entire mass must have
been one time in a state of liquidity or solution (aqueous or ig-
neous), sufficient to allow of that freedom of motion absolutely
essential to such an arrangement of the particles.*

It would be impossible to do justice to this subject without
more space, and many other illustrations, than are at disposal in
this communication ; some, however, which will serve to point
out the general features of the structure of this class of rocks,
are attempted in PI. XVII. figs. 1 to 8, and PI. XVIII. figs.
9 to 12.

The microscopic examination already made of many hundred
sections of eruptive rocks, differing widely in geological age and
geographical distribution, shows that in all rocks of this class,
whether of the most compact, hard, and homogeneous appear-
ance, or occurring in the softest and finest powder, like the
ashes and dust frequently thrown out by volcanoes ; a similar
crystallised arrangement and structure is present and common
to them all. Lavas, trachytes, dolerites, diorites, porphyrites,
syenites, granites, &c., all possess the same general structural
features, serving to distinguish the eruptive rocks as a class from
all others.

In the examination and discrimination of the minerals which
compose these rocks, especially when close-grained, the micro-
scope is quite indispensable, since without it no such enquiry
could be attempted. In these examinations, the assistance of
polarised light is most valuable ; but the space, unfortunately,

* Experiments show that analogous structure can be produced by at least
three different methods, all of which, however, agree in the necessity of the
mass being in a state of complete liquefaction previous to crystallisation ;
from —

1. Their solutions in water or other menstrua.

2. Aqueous fusion or melting of hydrated bodies in their water of
crystallisation.

3. Igneous or hydro-igneous fusion.

Crystalline structure may nevertheless develop itself by a molecular
movement in solid bodies without change of external form or previous
liquefaction ; as will be hereafter explained, this is frequently the case in
nature. The structure so developed is, however, very distinct from the
crystallisation after liquefaction, characteristic of the eruptive rocks.

360

POPULAR SCIENCE REVIEW.

only allows of a mere mention of its application. In distin-
guishing dolerites from diorites, when fine-grained, as is often
of considerable geological importance, the fibrous structure of
the hornblende of the latter is generally so well developed (PI.
XVII. fig. 6), even when present in very minute quantity, as to
distinguish it readily from the augite of the former, which pos-
sesses no such structure. Even in the case of Uralite, a mineral
characteristic of certain porphyritic rocks, which has the ex-
ternal form of augite, although its chemical composition is that
of hornblende, the fibrous structure characteristic of hornblende
is distinctly visible (PI. XVII. fig. 7). The microscopic struc-
ture of some minerals, however, varies with their origin ; thus
Sorby has shown that the structure of augite, and some other
minerals in meteorites, is quite distinct from that of the same
minerals occurring in eruptive rocks, and demonstrated, in a
very striking manner, how the study of such peculiarities is
likely to clear up the mystery in which the origin of these bodies
is involved.

When, as is often the case, especially with translucent, colour-
less minerals like quartz, leucite, calcite, felspar, &c., the appear-
ance presented under the microscope is alike, their optical
properties and the use of polarised light afford the means of
distinguishing between them with certainty; as, also, in the
event of one substance being present under two forms, as calcite
from aragonite, monoclinic from triclinic felspars, &c. In a
similar manner, the structure, whether crystalline or vitreous, is
determined, and valuable information obtained, elucidating the
mode of formation and origin of the rocks themselves.

The alterations produced in eruptive rocks subsequent to
their solidification, by the action of water, atmospheric or other
agencies, are studied with advantage under the microscope. For
want of space, a single example can only be here given, and is
depicted on PI. XVIII. fig. 12.

In this section, the skeleton of labradorite is seen remaining
as evidence of the original crystallised structure, whilst the
interstices contain the products of the alteration of the more
easily decomposable augite, the structure of which is nearly ob-
literated, and part of its lime converted into carbonate. The
rock in question is the so-called “ white horse ” of Staffordshire,
found embedded in or breaking through the coal measures,
which are frequently burnt or altered at points of contact with
this rock, which itself often has the appearance of a whitish clay.
The origin of this rock, whether sedimentary or igneous, was
disputed until the more recent geological and chemical examina-
tions of it have proved satisfactorily its identity with the Eowley
basaltic rock, very similar to that of Poukhill (PI. XVII. fig. 5).

PI. XVIII. fig. 13, is a section of a crystalline slag produced in

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361

silver smelting, and is here given for the sake of comparison with
the structure of eruptive rocks. In formation it is so nearly
identical with what is seen in sections of more felspathic basaltic
rocks, the mass of which consists of a framework of interlaced
crystals of labradorite with the interstices filled up with the
other mineral constituents confusedly crystallised, that this
section might easily be mistaken for such. The Eowley rag,
when fused and very slowly cooled, presents a similar appear-
ance ; and, in general, the structure of crystalline slags presents
many features in common with that of ordinary eruptive rocks.

Before proceeding to the next class of rocks, the discovery by
Sorby of the numerous minute fluid cavities in the quartz of
granites should be alluded to, as proving the great value of
the microscope in the study of these rocks. The result of this
gentleman’s researches * proves that granites have solidified at
a heat far below the fusing points of their constituent minerals,
and at such a pressure as to enable it to entangle and retain a
small amount (J to J per cent.) of aqueous vapour, which
naturally must have been present during its liquefaction. The
presence of these fluid cavities in the quartz of granite was
immediately blazoned forth as proof positive of the non-igneous
origin of granite ; whereas if Mr. Sorby’s memoir had actually
been read, it wTould have been seen that he had found fluid
cavities, perfectly identical with those in granite, not only in the
quartz of volcanic rocks, but also in the felspar and nepheline
ejected from the crater of Vesuvius; and that the presence of
fluid, vapour, gas, and stone cavities, are common both to the
volcanic quartz-trachytes and to the oldest granites ; and the
inference drawn by Mr. Sorby from the results of his researches,
is that both these rocks were formed by identical agencies. He
therefore classes them together under one head as rocks of
similar origin, f

II. Secondary or Sedimentary Eocks.

The rocks pertaining to this class are all, directly or indirectly,
formed from the breaking up, or debris, of previously existing

* Quart. Jour. Geol. Soc. vol. xiy. pp. 453 — 500.

t These researches tend to confirm the theory of the igneous origin of
granite and eruptive rocks in general. It must not he forgotten that by igneous
action , as used by the Piutonist, was always understood the action of heat as
developed in volcanoes (the study of which was the basis of the theory itself),
in which the agency of water was always recognised. Nearly half a century
ago, Scrope not only insisted on the important part played by water in vol-
canic action, but specially pointed out the difference between such volcanic
fusion and ordinary melting. The term hydro-igneous action might not be
inappropriate for such, but hydro-thermalism does not at all express what is
intended. The idea of a true dry fusion in nature exists only in the brains
of the ultra-Neptunist or lukewarm hydrothermalist.

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POPULAR SCIENCE REVIEW.

rocks, and, for that reason, might, as before mentioned, not
inappropriately be termed derivate rocks. When found in the
normal state of sedimentary deposition, they may be conveniently
subdivided into —

1. Eocks formed of the immediate products of the breaking-

up of eruptive rocks.

2. Eocks built up of the more or less rounded or angular

debris of previously existing sedimentary or eruptive
rocks.

3. Eocks composed of mineral substances extracted from

aqueous solution by crystallisation, precipitation, or the
action of organic life.

1. Rocks composed of the immediate products of the breaking
up of eruptive rocks. — The little attention paid by geologists in
general to the study of rocks of this class, has introduced the
elements of confusion into many of their enquiries, and frequent!}7
has led to very erroneous opinions being formed as to the nature
and origin of certain rocks, which could never have been enter-
tained had microscopic investigation gone hand in hand with
field observation.

Eocks of this class may either be of subaerial or subaqueous
origin; in the former case, for example, volcanic ashes may
have been deposited as beds on the surface of the land, and
afterwards been covered by lava streams poured out over them ;
or, from having been depressed below the sea level, may have
had sedimentary beds of aqueous origin subsequently superposed
on them.

Yv7hen of subaqueous origin, as is by far the most common
case, subaerial or subaqueous outbursts may force into the sea
eruptive rocks, which, being at once broken up into a state of
division, more or less fine, in proportion to the greater or lesser
cooling power of the water mass in immediate contact, may be
spread out into beds by the action of the waves : the texture of
these rocks may vary from that of the coarsest breccia down to the
finest mud, and, as is usually the case, such deposits may present
themselves as alternating beds of coarse and fine character.
Upon the consolidation of such formations, rocks are formed,
identical in chemical and mineralogical composition with the
original eruptive rock from which they were derived, and which,
particularly when close-grained, often present an external ap-
pearance so like the original rocks as to be frequently undis-
tinguishable from them by the naked eye ; in such deposits it is
often easy to pick out specimens having all gradations in appear-
ance from the above described down to such as would be attri-
buted to the consolidation of mere detrital mud.

No wonder, therefore, if the field geologist finds himself

*200

YTWest

Plate JVU]

Microscopic Structure of Hocks

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363

bewildered under such circumstances, and inclined to settle
down in the comfortable belief of the transmutation or transition
of sedimentary rocks into eruptive, &c., and even the chemist
feels puzzled, when he finds that a rock taken out of apparently
normal stratified deposits has the same chemical composition
with one of undoubtedly intrusive nature. The microscopic
examination, however, soon shows that, however similar the
external appearance of two such rocks might be, their internal
structure is totally different ; showing in the primary rock the
crystallised structure and arrangement previously described,
whilst the secondary rock is resolved into a mere agglomeration
of more or less broken fragments of the same minerals consti-
tuting the former. In beds formed from the consolidation of
volcanic ashes, the microscopic examination occasionally affords
evidence as to whether such ashes had been deposited on land,
or had fallen into water.

2. Rocks built up of the more or less rounded or angular
debris of previously existing sedimentary or eruptive rocks. —
Where sufficiently coarse-grained, these rocks constitute ordinary
conglomerates, breccias, grits, sandstones, &c., and are easily
analysed by the eye; but if fine, as shales, slates, &c., the
microscope must be appealed to, in order to resolve them into their
constituent mineral or rock particles, and by this means it will
be seen that even the most compact and homogeneous specimens
are a mere aggregate of more or less rounded and water-worn
grains of quartz, weathered felspar, mica, chlorite, soft and hard
clays, clay slate, oxide of iron, iron pyrites, carbonate of lime,
fragments of fossil organisms, &c., arranged without any trace
of decided structure or crystallisation, even when the highest
powers of the microscope are employed in their examination.
The physical structure and optical properties of the mineral
components enable them, however, to be recognised with great
certainty, even when in grains of less than YoVo an ^EL
diameter.

PL XVIII. fig. 14, shows the appearance of a section of a fine-
grained (uncleaved) Silurian clay slate from Sorata, in Bolivia,
magnified 400 linear. This rock is composed of irregular grains
of quartz sand, weathered felspar, and waterworn mica, along
with specks of oxide of iron and iron pyrites, all promiscuously
mixed.

In the case of roofing slate, however, the microscope shows
that the constituents, instead of being distributed at random
throughout the mass, possess a definite arrangement, as may be
seen in the section of lower Silurian roofing slate from the
Festiniog quarries (PL XVIII. fig. 15), where they are disposed
in parallel lines, thus constituting lines of weakness or the cleav-
age of the slate. The researches of Sharpe and Sorby have con-

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POPULAR SCIENCE REVIEW.

clusively proved that this has not resulted from any chemical or
crystalline action whatsoever, the particles being in themselves
perfectly unaltered ; and that the arrangement is solely due to
the effects of pressure, applied at right angles to the structure
itself, thereby causing an elongation or flattening out of some,
along with a sliding movement of other of the particles. The
amount of compression to which an ordinary roofing-slate has
been subjected in one direction, has been calculated, approxi-
mating from the elongation or distortion of the particles, to be
about equal to one-half of its original volume.

Besides the cleavage structure, so produced by the compression
of rocks whilst in a more or less plastic state, Mr. Sorby has
shown that another system of minute jointing may also be present
in these rocks, the serrated edges of which, as seen by the micro-
scope, prove it to have been the result of force applied to the
rock subsequently to its having been in a perfectly rigiT condition.

Kocks of this class, when somewhat close-grained and much
indurated, have not unfrequently, from their external appear-
ance, been mistaken for intrusive rocks : thus the rock shown in
section, PI. XVIII. fig. 16, an upper oolitic, highly-inclined
shale bed, has been mapped by D’Orbigny as an eruptive green-
stone ; the microscopic structure proves the contrary most con-
clusively.

3. Rocks composed of mineral substances extracted from
aqueous solution by crystallisation , precipitation , or the
action of organic life. — Under this class are included most
beds of gypsum, rock salt, and other saline bodies, as well as
travertine, siliceous sinter, flint, infusorial slates and earths,
limestones, &c., many of which have been as yet but very
superficially examined.

In the microscopic investigation of such rocks as owe their
origin to the development of organic life, very considerable pro-
gress has been made, with correspondingly important and in-
teresting results.

As early as 1836, Ehrenberg proved that large rock masses
were built up of the carapaces of minute siliceous infusorise, and,
more lately, Sorby has done good service by his investigation of
limestones ; these he has proved not to have originally possessed
any crystalline structure whatsoever, but to have been deposited
as mere mechanical aggregates (aptly termed by him, organic
sands or clays) formed of the debris of calcareous organisms,
which admit frequently, not only of being recognised, but of
having their relative proportions determined. The comparison
of the microscopic structure of the organisms in chalk, with
those now forming in the depths of the Northern Atlantic
Ocean, indicates that there is an immense deposit now in course
of formation, quite analogous to what had previously taken place

THE MICROSCOPE IN GEOLOGY.

365

in the seas of the cretaceous period ; and the same able observer
has shown that the reason why certain calcareous organisms are
found so well preserved, whilst others had disappeared or become
entirely disintegrated, was from the carbonate of lime in the
first being in the form of the stable calcite, whilst in the latter
it was present as instable Aragonite.

When a calcareous rock has undergone cleavage, the micro-
scope shows a distortion of its particles and organisms, just as in
a cleaved slate, though in much less degree; the measurement
of such distortion serves as a basis for estimating the amount
of compression undergone.

With the exception of having briefly referred to the alterations
in igneous rocks, subsequent to their solidification, and the
cleavage of sedimentary beds, all the classes of rocks treated of
have been considered in their normal or unaltered condition ; it
remains now to direct attention to the use of the microscope in
the study of subsequent alteration or metamorphism of rocks.

Many sedimentary beds become more or less indurated, at
points where they are cut through by eruptive dykes ; thus the
coal-shales and clays of Staffordshire are found altered into a
hard rock with conchoidal fracture, or even into porcellanite,
when in immediate contact with basaltic dykes. An examination
shows no change in mineral or chemical composition beyond the
expulsion of the water always contained in such beds, and
sections of such rocks are often seen to be quite identical in
structure with those of common stoneware made from the same
clays, the only difference being that the latter is usually more
porous from not having been submitted to the pressure which
rocks baked in situ would experience.

The alteration of rocks produced by infiltration may or may
not be accompanied by chemical changes ; thus a section of
calcareous grit often shows that the calcite filling up the inter-
stices between the grains of sand has been merely deposited from
a solution of carbonate of lime which has percolated through it,
and in otherwise unaltered limestones it is common to find
microscopic veins of calcspar, due to minute cracks or fissures,
filled up in a similar manner. Frequently, however, such infil-
tration is accompanied by an entire change in the chemical
composition of the rock itself ; thus the beds of Cleveland iron-
stone have been proved by Sorby’s microscopical researches to
have been originally shell limestones converted into carbonate
of iron by the action of ferruginous solutions, the fragments of
the original shells being still distinguishable in all stages of
conversion ; in the same manner he has proved the magnesian
limestones of the Carboniferous and Devonian ages, as well as the
Permian dolomites, to have been originally common limestones,
or aggregations of organic debris, the particles of which, by the

366

POPULAR SCIENCE REVIEW.

use of the microscope, can be traced back to their original un-
altered state, from which they have been changed by the action
of magnesian solutions.

The metamorphism of rocks produced by gasolytic action, as,
for example, carbonate into sulphate of lime, &c., has, as yet,
not been made the subject of microscopical enquiry.

The foliated schists, quartzites, &c. form by themselves a
distinct and well-defined class of metamorphic rocks, charac-
terised by structural peculiarities differing from all previously
treated of.

This appears to be due to their crystalline development having
originated in a solid body, and not from liquefaction ; the
minerals composing them differ greatly in structure from the
same minerals when found in eruptive rocks. Instead of, as in
the latter case, presenting themselves in more or less defined
crystals, occurring in all positions and at all angles to one
another, in the foliated rocks they are developed only in one
general direction, not characterised by well-defined bounding
planes, but forming a string of drawn-out and irregularly
bounded crystalline aggregations, presenting a general parallelism
to one another, as is illustrated by PI. XVII. fig. 8, which shows
a section of hornblende schist from Connemara.

The microscopic examination of these rocks proves their
original sedimentary origin, often showing the contours of the
original sand grains, and, as Sorby has pointed out, the existence
of ripple-drift and wave-structure, peculiar to sedimentary rocks
alone. These rocks appear to have been micaceous and argilla-
ceous sandstones, the constituents of which have been recrystal-
lised in situ, owing to molecular action developed in the solid
rock.

The quartz of these schists frequently contains numerous fluid
cavities, indicating that they have been exposed to a pressure
under which the water, always present in more or less quantity
in sedimentary rocks, has been entangled and retained during
the recrystallisation of the quartz.

The direction of the lines of foliation or crystalline develop-
ment is that of the lines of least resistance in the rock, which
commonly will be the lines of stratification, but in cleaved rocks
will doubtless be those of cleavage. Sorby has alluded to this
fact by the names of u stratification foliation ” and u cleavage
foliation.”

In conclusion, the author of this short sketch hopes that it
may be the means of attracting attention to the subject, and
thereby of causing a hitherto almost unexplored field of micro-
scopic enquiry to be more cultivated ; and leaves it to his readers
to form a correct estimate of the justness of the sneering assertion
that “ mountains should not be looked at through microscopes.”

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367

DESCRIPTION OF PLATES.

PLATE XVII.

Fig. 1. Section of greyish black slaggy lava from Etna, magnified 25
linear. Although this rock appears perfectly amorphous to the eye, it is here
seen to he composed of crystals of greenish brown augite, colourless felspar,
and opaque magnetic oxide of iron ; the interstices being filled up with an
admixture of the same minerals less distinctly crystallised. This specimen
was, by means of a pole, lifted by the author, on the 21st of May, 1865, out
of the grand current of lava then flowing out from the north side of the
crater of the volcano.

Fig. 2. Section of lava from Vesuvius, magnified 12 linear. This speci-
men was taken by the author from the current of a.d. 79 covering Hercula-
neum, and was a somewhat porous, but hard dark grey rock, containing
abundant crystals of augite, which are well shown in section.

Fig. 3. Section of a volcanic rock, magnified 12 linear, consisting of
felspar with some olivine and magnetic oxide of iron, with numerous crystals
of a pyroxenic mineral, all well shown in this section. The specimen was
taken by the author from the Valley ^of Papenoo, in Tahiti.

Fig. 4. Section of the pitchstone occurring in dykes breaking through
the new red sandstone in the island of Arran, magnified 75 linear. In
external appearance it resembles a dirty green bottleglass, but under the
microscope shows a beautiful arborescent crystallisation of a green pyroxenic
mineral, embedded in the colourless and transparent felspar base.

Fig. 5. Section of a portion of a basaltic column from Poukhill Quarry,
near Walsall, Staffordshire, magnified 30 linear. This rock intrudes into
and disturbs the coal measures, and is seen to be composed of crystals of
felspar, augite, and titanoferrite, with a little of a green mineral, probably
the variety of augite called seladonite.

Fig. 6. Section of diorite (auriferous), taken by the author from near
Tres Puntes, in the Desert of Atacama, Chili, magnified 30 linear. It con-
sists of felspar with hornblende, and, in the section here represented, groups
and isolated crystals of iron pyrites are seen, which frequently accompany
this rock, and with which the gold is associated.

Fig. 7. Section of uralite porphyry, from Predazzo, Tyro], magnified 12
linear. It is composed of felspar with uralite, a mineral having the ex-
ternal crystalline form of augite, with the chemical composition of horn-
blende.

Fig. 8. Section of hornblende schist, cut at right angles to the plane of
foliation, and magnified 12 linear. It is composed of hornblende and quartz,
the latter recrystallised, but still showing traces of the outlines of the original
sand grains : upon examination under a higher power, the quartz will be
seen to contain numerous fluid cavities. The parallelism of the foliation,
although perfect when viewed on the large scale, is naturally somewhat
indistinct in a fragment so small as can be taken into the field of the
microscope. It is evident, upon inspection, that the structure of such a
rock is totally different from that seen in the sections of eruptive rocks.

368

POPULAR SCIENCE REVIEW.

PLATE XVIII.

Em 9. Section of granite from St. Just, Cornwall, magnified 25 linear.
It consists of crystals of ortlioclase, hexagonal ditto of brown mica, and of
colourless quartz ; the latter, when examined by a higher power, is seen to
contain fluid cavities.

Fm 10. Section of volcanic quartz trachyte from Jacna, Peru, magnified
10 linear. It consists of quartz crystals, often large and well defined, along
with smaller hexagonal plates of black mica, scattered through a felspathic
mass indistinctly crystallised. The quartz of this trachyte also contains
fluid cavities (seen by employing a higher power), similar to those occurring
in the quartz of granite. This rock is developed very extensively along the
volcanic range of the Andes of South America.

Fig, 11. Section of a volcanic rock, taken by the author from the foot of
the volcano of Ariquipa, in Peru, magnified 6 linear. This rock is of a grey
colour, and has a porphyritic structure, arising from crystals of white felspar,
scattered through a grey base, which the microscope shows to be composed
of felspar, dark brown-black crystals of augite, hexagonal crystals of almost
black mica, and a little magnetic oxide of iron.

Fig. 12. Section of the so-called a white horse ” dykes, intersecting and
altering the coal measures of Staffordshire, magnified 35 linear. The frame-
work of felspar crystals still remains unaltered, whilst the other mineral
constituents are decomposed so far as to be frequently unrecognisable. Its
chemical composition, in conjunction with the microscopic structure, show
this rock to be similar to that from Poukhill (PL XVII. fig. 5), more or less
altered by the action of water.

Fig. 13. Section of a crystalline slag from smelting silver ores, magnified
30 linear. The structure is seen to be very similar to that found in many of
the more felspathic doleritic rocks.

Fig. 14. Section of fine-grained Silurian (uncleaved) slate, from Sorata,
in Bolivia, magnified 400 linear. It is seen to be a mere mechanical aggre-
gate of minute, irregularly weathered, or rounded particles of sand, clay,
mica, oxide of iron, &c., without any trace of arrangement or crystalline
structure being visible.

Fig. 15. Section of Lower Silurian roofing-slate, from Festiniog, North
Wales, cut at right angles to the cleavage, and magnified 200 linear. This
shows that the parallel structure of cleavage is due entirely to the mechanical
arrangement of the unaltered particles of the rock, and not to the develop-
ment of any crystalline structure.

Fig. 16. Section of a highly indurated bed in the upper oolitic series at
Iluaylillos, Peru, magnified 30 linear, and in external appearance so much
resembling an eruptive rock as to have been mapped as such by D’Orbigny.
The microscopical examination, however, at once shows its true sedimentary
character, and resolves it into a mere mechanical aggregate of quartz, "sand,
&c., without any of the crystalline character peculiar to eruptive rocks.

369

* f

WHY THE LEAVES FALL.

By MAXWELL T. MASTERS; M.D. F.L.S.

SCARCELY less wonderful than the gradual advent of the
leaves in spring, is their successive disappearance at the
close of autumn. In every age moralists and poets have found
illustrations for their themes in the hopeful bursting into leaf
of the tree in spring, or in the inevitable fate which in early
winter breaks up the rich billowy masses of foliage, and sends

a The sere leaves flitting on the blast.”

It is remarkable how many analogies may be drawn between
natural phenomena and the attributes of human nature. Now
we find the life of man compared to a river, at another time to
a glacier, it may be to a cloud ; but however apposite these
comparisons may be, they are certainly not more so than is the
analogy that may be drawn between the life of the leaf and that
of the human race. Both have an innate power of growth, in
both equally are the seeds of decay early implanted, which
develop and fructify in due time, counterbalance the powers of
growth, and ultimately bring the worn-out structure to the
ground.

u Like leaves on trees the race of man is found,

Now green in youth, now withering on the ground ;

Another race the following spring supplies,

They fall successive, and successive rise ;

So generations in their course decay,

So flourish these, when those have passed away.”

But now-a-days we are not content merely to draw analogies,
however correctly ; we leave the poet to make his own use of the
facts presented to him by adorning a moral or pointing a tale,
but more prosaic people seek to know the why and the where-
fore of the facts presented to their notice, and thereby, in spite
of what may be said to the contrary, to increase the store of
illustrations for the poet by opening up to him new marvels and
deeper and more comprehensive analogies.

370

POPULAR SCIENCE REVIEW.

Why, then, do the leaves fall ? is the query to which we
purpose in the present article to supply a response as far as we
are able to do so.

In attempting to give an answer to the question, it maybe as
well to go a little into detail, which will serve the more clearly
to render intelligible what really is known about the fall of
the leaf, and will also indicate certain points which up to the
present time have scarcely received a satisfactory explanation.

We may premise that all the many reasons that have from
time to time been given to account for the process of defoliation
may be ranged into those which are of a purely mechanical
nature, and which are very much under the influence of external
conditions of climate and the like, and those which are of a
structural or organic character, being only secondarily mecha-
nical in their action, and less directly influenced by external
conditions.

There are such differences in the length of time that leaves
remain attached to the stem, such variation in the method of
detachment, that it would seem probable that the causes pro-
ducing these varied results may themselves be diverse, that in
one case one cause may be potent, in another instance the result
may be due to some other agency, while in a third series, per-
haps, the effect may be the result of the joint action of more
than one factor. Thus, while some leaves fall off comparatively
soon after their expansion, such as those which are technically
termed caducous or deciduous, others are persistent, while to a
few, which seem never to be shed, the term evergreen, which is
generally inappropriate, may fairly be applied. Where leaves
fall off very early, it will be found generally that they serve the
purpose of protection merely ; such are the small rudimentary
scaly leaves which envelop the leaf-buds in most of the trees
and shrubs of this country. Formed at the close of the year
around the young bud, they shield and protect it during winter,
and when the returning warmth of spring urges the dormant bud
into growth, the scales are pushed off by the constantly increas-
ing pressure of the rapidly enlarging bud. On the other hand,
where, as in the Araucaria, the leaves are never shed, their in-
ternal organisation approaches in many respects to that of the
stem ; indeed, it becomes a question in such a case whether the
so-called leaves are not merely portions of the stem. Between
these extremes there is a large class of deciduous trees or shrubs,
which shed their leaves, some sooner, some later, but at a toler-
ably regular, determinate period, according to the particular
species, and according, as we shall see presently, to external
circumstances. Thus, while the lime, in the southern parts of
Britain, loses its leaves early in September, the walnut soon after-
wards, to be followed in their turns by the elder and the horse-

WITT THE LEAVES FALL.

371

chestnut, there are others, such as the beech, the hornbeam, and
some varieties of oak, which retain their leaves for the greater
part of the winter, though generally in a dried, withered state,
and do not part with them till forced to do so in spring by the
gradual distension of the newly awakened buds.

Gardeners were wont at one time, much more than at present,
to make use of hornbeam hedges to afford shelter to their
plants in winter, just as they do now with hedges of yew.
In Holland, it is not unfrequent to see the brown withered
foliage of the beech, or the hornbeam, contrasted with the rich
dark green of the ivy, and making a screen at once useful and
agreeable to the eye. It is noteworthy, that, in the case of the
beech at least, the petiole becomes quite woody in its texture,
and is not so easily cast off as some wherein the tissues are
softer.

Plants, too, have their idiosyncrasies as well as other creatures.
There are some which will develop their leaves a fortnight or so
earlier than their brothers of the same species, others that will
retain their foliage long after it has fallen from other plants of
the same specific form. This did not escape the notice of the
old Greek naturalists, for Theophrastus, in his work “ De
Plantis,” mentions a plane-tree in Crete, which never shed its
leaves, and he adds, that that was the identical tree beneath whose
shade Jupiter carried on his flirtation with Europa. Be that as
it may, it is quite certain that, apart from individual peculiarities,
such as we have just mentioned, plants of the same species will
shed their leaves sooner or later according to the locality in
which they grow. In the Canary Islands the vine only sheds its
foliage very gradually, so that new leaves often appear before all
the old ones are thrown off. The cherry-tree in Ceylon, and the
peach in Brazil, are said to become almost completely evergreen.
On the other hand, in colder latitudes than ours the leaves fall
earlier, in consonance with the earlier advent of winter. In the
tropics, although there is in general not so well-marked a
period of defoliation, yet the dry season seems to act in a similar
way to the winter season here. Travellers tell us that there is
scarcely a month in the year in which young shoots and leaves
may not be seen on the trees, so that the formation of the young
leaves, as well as the fall of the old ones, is * spread over the
whole year, as it were, and is not so much confined to particular
periods as in temperate latitudes. The fall of the leaf cannot,
however, be attributed solely to the change in the seasons from
wet to dry, or from hot to cold, for it not unfrequently happens
that if a tree be stripped of its leaves in summer, it forms during
the autumn new ones, which remain on the tree during the
greater part of the winter, or at any rate until long after the
usual period. A similar occurrence was noticed in the Calcutta

VOL. VI. — NO. XXV. E E

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POPULAR SCIENCE REVIEW.

Botanic Garden by Dr. Anderson, after the terrific cyclone of
October 1864. Several trees which were denuded of their foli-
age by the wind produced new leaves, which, in place of falling
off as they do under ordinary circumstances in winter, remained
on the trees throughout that season. These trees did not, how-
ever, flower in the following spring, as they would have done
had there been no interruption to their ordinary course of
proceedings. On the other hand, some others, although they
produced a second crop of leaves after the cyclone, lost them
again in the winter, and flowered as usual n the spring. These
facts are very suggestive as to the relative interdependence
of leaves and flowers ; a subject which we must not, however,
dilate on in this place.

Drought seems to have as potent an effect in bringing about
the fall of the leaf as cold. In some of the Brazilian forests
during the dry season the trees are as bare as with us in the
depth of winter ; and a few summers since, when there was a
long period of drought, the trees on the sandy dry soil about
Bromley in Kent were as bare as in winter. Reasoning upon
facts such as these, it is not unnatural to conclude that the fall of
the leaf is in some way or other connected with evaporation or
exhalation of fluid from their tissues. This, as is well known,
takes place to a large extent, being regulated partly by external
circumstances, partly by internal organisation ; and it has been
proved experimentally by Lawes and others, that the so-called
evergreens, as a rule, evaporate less in proportion to the extent
of their leaf surface, than do ordinary plants ; and coupling this
fact with the known effects of drought on deciduous trees, it is
reasonable to suppose that the fall of the leaf is, in a measure
at least, dependent on the evaporation from the surface. This
explanation, however, is only partially satisfactory, for it will at
once be seen that in most cases the leaves fall not at a period
of drought, but in early winter, a time of comparative humidity,
when heat or drought, at any rate, would not give rise to dis-
proportionate exhalation.

Adverting now to the external configuration of the leaf, let
us see whether there may not be some mechanical cause for the
separation of the leaf from the trunk. In most cases the leaf-
stalk is attached by a broad base to the stem, so that when it
falls off it leaves a scar more or less like a horseshoe in shape :
on this scar may be seen the traces of the bundles of woody
tissue, which passing from the trunk traverse the petiole or leaf-
stalk on their way to the blade of the leaf, where they break up
into the so-called veins. Now an observation of the shape of
the scars, and of the disposition of the bundles of woody tissue
in them, in different plants, throws some light on the causes of
defoliation ; for instance, it is reasonable to surmise that where

WHY THE LEAVES FALL.

373

the leaf-scar is circular, in other words, where the leaf-stalk is
cylindrical, and the bundles of woody tissue are arranged in
a ring, the leaf would be less easily detached than in cases
where the bundles form a half-circle, merely leaving the upper
surface of the leaf-stalk comparatively weak from the presence
of cellular tissue only. In any case, the leverage exerted by
the flat surface of the leaf, acted on by every wind that blows,
must be taken into account.

Another reason that has been suggested for the removal of
the leaves, is the pressure exerted on the base of the leaf-stalk
by the axillary buds, which swell and increase in size notably in
the autumn ; but there are many things which show that the
swelling of the bud at this time of year has but little to do with
the shedding of the foliage ; for see how carefully pressure is
provided against by the flattening of the leaf-stalk at its base, or
even by its being scooped out spoon fashion to receive the bud.
Again, notice how often, when there is a chance of injurious
pressure being exerted, the stem bends away from the leaf
at an angle, as in what are called “ flexuose ” stems, so that no
hurtful pressure can take place. For the purpose of testing this
notion, we have, while writing these notes, observed a young
lime, which even thus early (August 7) is shedding its leaves.
The lime is a good tree to notice for this purpose, because its
stems are often more or less flexuose, and because its leaf-buds
are placed a little on one side of the leaf-stalk, and not im-
mediately in their axil ; moreover, as happens of course with
other trees, only a small proportion of the leaves foster in their
axils buds large enough to exert any possible pressure. The
vast majority of the axillary buds remain u latent.”

Now it might be expected, if it were true that the newly
formed buds pushed off the old leaves in autumn, that the lime-
tree would retain its leaves longer than most other trees, seeing
that its buds are not so placed as to be able to exert much
pressure, and that the stem is more or less flexuose. But what
is the case ? The lime is one of the earliest trees to part with
its leaves, and as the writer has observed, not only in the lime,
but in other trees, the presence or absence of an axillary bud
does not seem to make the slightest perceptible difference,
either in the period at which the leaves fall, or in the amount
of force requisite to detach them artificially. For experiments
of this kind, the common and the Neapolitan alder are suitable,
inasmuch as some of the buds in these trees are raised upon
short stalks, which, growing comparatively fast just before the
fall of the leaf, might be supposed to exert some influence on
that phenomenon. But here, again, the comparison of those
leaves which are provided with stalked buds, and those in which
no bud or only a rudimentary one is visible, does not show any

E E 2

374

FOPULAR SCIENCE REVIEW.

difference as to the period when they fall, or as to the weight
requisite to detach them. The influence, then, of the axillary
buds in detaching leaves in autumn (a very different matter
from the separation of the persistent leaves in spring by the
same organs), would seem to be nil, and we may turn to other
assigned causes. Among these are the formation of earthy or
mineral materials in the tissues of the leaf, to such an extent as
to block up the cells and impede their action. That such an
accumulation does take place, is easily proved by chemical
analysis and microscopical observation. The latter shows a
much larger proportion of raphides or crystalline deposit in the
cells in the leaves about to fall than at other times. The
falling leaves of the common cherry laurel, Prunus lauro-
cerasus , may be cited as affording a good illustration of this
accumulation of raphides, the more so as the leaves of this
plant, as of most of the so-called evergreens, are not shed in
greater numbers at the approach of winter than at any other
time, but are irregular in this respect. The accumulation of
earthy matters in the leaves serves to restore to the ground in
some measure the mineral ingredients taken from it by the
growing plant ; hence the impolicy of the practice, so often
followed in gardens to the detriment of the shrubs, &c., of re-
moving the fallen foliage from the soil ; if such be necessary for
purposes of neatness, some other provision should be made to
supply the soil with what is requisite for the growth of plants.
The storage in largely increased quantities of starch granules in
the cells, has also been noted by Dr. Inman and others, as
taking place in leaves just previous to their fall; and it is easy
to conceive that the distension of the tissues, and the impedi-
ment offered to the due discharge of their functions, might
facilitate the separation of leaf and stem.

But in the face of the facts already mentioned, and especially
when it is recollected how very “ clean ” is the fracture between
the leaf-stalk and its attachment, how it is nearly as even and
smooth as if the severance had been made with a knife, it be-
comes evident that whatever influence the circumstances before
mentioned on the phenomena in question may have, they can
but be secondary and indirect, and we are driven to seek some
cause in the organisation of the leaf itself. At one time it was
considered that the varying direction of the several layers of
tissue in the leaf-stalk would account for their separation, and
this would seem borne out by the very common arrangement of
the wrood cells of the leaf-stalk, nearly at a right angle to the
cellular tissue. This arrangement may be seen in many leaves, as
in Rhus typhinum, Gleditschia , &c., but according to Von Mohl,
it is far from being general. Schacht’s notion was, that the fall
of the leaf was due to the gradual intrusion of a layer of cork

WHY THE LEAVES FALL.

375

or periderm cells, which, passing through the leaf-stalk at nearly
a right angle to the other tissues, prevented the passage of the
sap from the stem to the leaf, and ultimately caused the detach-
ment of the latter, pretty much in the same way as that by
which the removal of the large slabs of bark from the plane-
tree is effected. Yon Mohl, however, shows that this statement
of Schacht’s is too general ; that the periderm layer is as often
absent as present ; and so far as we have ourselves noticed, the
periderm cells are often not formed till after the fall of the leaf,
when they gradually extend over the wound, and close it as by
a plaister. Yon Mohl’s account of what happens is as follows : —
Shortly before the fall of the leaf, there begins to be formed a
very delicate layer of cells, the growth of which is from above
downwards, so that, beginning from the axillary side of the leaf,
and gradually extending downwards and outwards nearly at
right angles to the long diameter of the cells of the leaf-stalk,
at any rate at right angles to the plane of the leaf, it effects a
gradual separation between the stem and the leaf as effectually
as a knife would do. The layer in question does not sepa-
rate, as might be supposed, the comparatively dry distal
portions of the leaf, from the still active cells of the stem, which
are filled with juices, but it is formed in the midst of soft tissue,
the cells of which are turgescent with fluids. It is, therefore,
not so much a separation of dead from living tissue, as a passage
of an active “ line of demarcation ” through living, still active
tissue. This “ separating layer,” unlike the periderm cells of
which Schacht speaks, is composed of young tissue endowed with
a large share of vitality ; its cells are usually filled with starch
and with albuminoid matters, indicative of a young and active
tissue. The vessels of the petiole, according to Yon Mohl, are not
affected at all by these changes ; they simply become broken
through as the leaf falls. We allude to the spiral and pitted
vessels especially, and not to those “ vasa propria ” which have
of late been so minutely studied by M. Trecul. The latter ob-
server, in the Gomjptes Rendus , July 1, 1867, p. 25, mentions
the formation, in the vasa propria, of a layer of cells, just prior to
the fall of the leaf, in several plants. The effect of this forma-
tion of new cells is to fill up and completely obstruct the reser-
voirs of secretions. These cells are said by M. Trecul to be
formed from the subdivision and growth of those forming the
boundaries of the channels in question, and thus are wholly dif-
ferent from those constituting the separating layer of Yon Mohl,
though it is obvious that they must have a similar effect in
promoting the detachment of the leaf from its support. It may
be as well to point out that the circular constriction so often
seen at the base of a leaf-stalk, forming the joint, or articulation,
as it is called, exists from the beginning, and while it indicates

376

POPULAR SCIENCE REVIEW.

nearly the ultimate position of the cc separating layer,” yet it is
not itself to be considered as the commencement of that layer.

The constriction may readily be seen throughout the whole
summer, and by microscopical examination it may easily be
noticed to be purely superficial; moreover, it is much more
marked on the lower than on the upper surface ; while the
“ separating layer,” on the other hand, travels, as we have seen,
from within or from above downwards and outwards. The
reader will find it easier at any time to detach a leaf from the
stem by bending it downwards than by forcing it upwards, a
result that would be reversed if the constriction were really, as
it is so often considered to be, the provision made aforetime for
the ultimate removal of the leaf. What, then, is this constriction ?
To answer this question, we must refer to Eichler’s thesis on the
development of leaves, of which Dr. McNab * has given an
abstract in English with comments and additional observations
of his own. According to these observations, the first stage in
the formation of the leaf is the production of a little pimple of
cellular tissue on the side of the stem ; this receives the name of
<f phylloblast,” and after a time it divides into two portions, a
proximal portion next the stem, which Dr. McNab calls the
6C hypophyll,” and a distal portion called the te epiphyll;” from
this latter, the true leaf with its stalk is evolved, from the
former (which seldom assumes any large size) the stipules are
produced when these organs are developed.

Applying these facts to the fall of the leaf, it will be seen
that the separation takes place below the swollen base of the
leaf-stalk, beneath what is technically called the u pulvinus,” and
hence the constriction so often seen in that situation indicates
the original line of separation between the “ hypophyll ” and the
“ epiphyll.” This at any rate seems ver}7 probable. But whether
this be so or not, the detachment takes place, not precisely
between leaf and stem, but between leaf and <£ hypophyll,” the
latter being intermediate in position between leaf and stem, and
structurally more nearly allied to the latter than to the former.
The formation of a separating layer in the way we have explained
is not unique ; analogous instances may be seen in the fall of
the fruit. On the freshly detached surface of a pear-stalk, a
white mealy appearance may be seen by the naked eye ; on
microscopical examination this will be found to be due to the
formation of a layer of new cellular tissue.

On the whole, then, of all the assigned causes for the fall of
the leaf, this last, dependent on an alteration, or rather on a new
growth in the leaf itself, is the most important, and probably the
only one of itself sufficient to produce the result. It remains now

* Trans. Bot. Edinb. 1865, 1866.

WHY THE LEAVES FALL.

377

to be seen whether this separating layer is of universal formation
in the case of deciduous leaves. For many reasons we are inclined
to think that it is not formed when leaves fall off prematurely,
as they do from drought or injury. But supposing it to be of
general occurrence under what we may term ordinary circum-
stances, it still remains to be ascertained what are the precise
conditions inducing the formation of this peculiar layer of tissue.
It is easy enough to say that the layer in question is formed
owing to the disproportionate growth of the tissues, those of the
stem being active, while those of the leaf are obstructed and
comparatively inert. This may be so, but there is no direct
evidence on the point as yet. We admit the facts, but the
precise relation of those facts one to another is not yet fully
made out ; till this is done, the explanation of the fall of the
leaf cannot be considered as fully satisfactory.

378

“A MESSAGE FROM THE STARS.”
By ROBERT HUNT, F.R.S.

AH attentive study of the philosophy of the experimental
sciences, will speedily lead to the conviction, that many
of the simplest phenomena, which, from their constant re-
currence, are ordinarily regarded as common-place and insig-
nificant, contain the germs of truths of the most exalted
character. The laundress who spat upon her smoothing-iron
to determine if it was hot enough for her purpose, never dreamed
of the “ spheroidal state ” of matter, or fancied that her simple
test would lead to important discoveries in connection with
heat, or advance us to the magical experiment of freezing water
in red-hot vessels. Yet so it was.

With the spontaneous evaporation of water — the drying of
linen for example — everyone has been acquainted for ages.
Yet this diffusion of vapour into the air failed to teach man a
great truth until recently. The adhesion of water to a perfectly
smooth and clean piece of glass, and the “ sucking up ” of the
same fluid by a sponge, or by a lump of white sugar, though
constantly observed, never instructed the observer until lately
in the action of material surfaces on fluids and gases, or indicated
to him the existence of a Force, or Forces, surrounding every
atom, which appear capable of exerting an intense mechanical
power of condensation. The careful study of these phenomena
has, however, gradually advanced us from one discovery to
another, until it has enabled us to read with precision a great
truth, brought to us by a Meteorite, which once moved in the
remote spaces through which comets travel, and where nebulae
are slowly concreting into worlds. It is necessary for the correct
understanding of the curious results obtained by Mr. Graham,
which have advanced our knowledge by certain steps, to the
remarkable discovery of the Occlusion of Hydrogen Gas by
Meteoric Iron , that we should concisely trace the progress of
the enquiry from its earliest development.

To Dr. Priestley * we are indebted for the earliest observations

* Priestley, u Experiments and Observations on Different Kinds of Air,”
iii. p. 29.

379

“ A MESSAGE FEOM THE STARS.”

we possess in relation to this subject. Having occasion to
transmit a gas through stoneware tubes surrounded by burning
fuel, he discovered that the tubes were porous, and that the gas
escaped outwards into the fire, while at the same time the
gases of the fire penetrated into the tube. Priestley does not
appear to have had any idea of the value of this observation :
it was to him a barren fact. Dr. Dalton perceived the im-
portant indication, and clearly saw the bearing of Priestley’s
observation on the properties of aerial bodies. Experiments,
well devised and cautiously varied, led him to the discovery
that any two gases, allowed to communicate with each other,
penetrated each other, or mixed, in opposition to the influence
of their weight. Taking the lightest known gas, hydrogen ,
and the heaviest, carbonic acid , he placed them in two vessels
which communicated with each other, so that the dense gas was
in the lower vessel. According to the solicitation of gravity,
the two gases should have remained as they were arranged ; but
it was found that the lighter gas descended and the heavier one
ascended, until, in a few hours, they became perfectly mixed.

But for the operation of this diffusive power, the healthful
condition of the Earth’s atmosphere would not be maintained.
When a light and heavy gas are mixed , they do not exhibit any
tendency to separate on being allowed the most perfect repose.
Common air is essentially a mixture of oxygen and nitrogen :
these gases differing in weight in the proportion of 971 to 1105.
Yet if a closed tube of air, many yards in length, be kept
upright and perfectly still for months, no change whatever takes
place, the air at the top and that at the bottom of the tube
being in precisely the same condition. If, however, into a
similar tube we pour a heavy gas, and then carefully float on it
a light one, they will have diffused thoroughly in a few hours,
every portion of the tube containing the same mixture.

Mr. Graham found that gases diffuse into the atmosphere,
and into each other, with different degrees of ease and rapidity.
His mode of observing this was by allowing each gas to diffuse
from a bottle into the air through a narrow tube, arranged in
such a manner that the gas had no tendency to flow out , but
was compelled to diffuse in opposition to the effect of gravity.
Each gas penetrates into the space occupied by the other, not
at the same rate in both directions, but according to a well-
determined law. To express this disposition — or rather diversity
of disposition — in gases to interchange particles, the term
diffusion volume has been adopted. The diffusion volumes are
inversely as the square root of the densities of the gases, and
the times of effusion and diffusion follow the same law.

It has been found convenient to adopt with precision the
following terms : effusion, or pouring out — this expresses the

380

POPULAR SCIENCE REVIEW.

passage of gas into a vacuum by a small aperture in a thin
plate ; transpiration , the passage of gases through tubes of
fine bore and of some length ; diffusion, or the power of inter-
penetration ; and evaporation , which is the ordinary process
of spontaneous vapour diffusion.

The general laws which regulate the latter alone need claim
our attention. It is desirable to show that the ordinary process
of evaporation is one of diffusion, and that, differing only in
degree, it presents a striking analogy to the diffusion of gas
through gas, and of fluid through fluid. The spontaneous
evaporation of water into air is affected by three circum-
stances. 1st. The dryness of the air. A certain fixed quantity
only of water vapour can rise into air. Dr. Dalton discovered
that the evaporation of water has the same limit in air, as in a
vacuum. It is only necessary to know what quantity of any
vapour rises, at a particular temperature, into a vacuum, and
we learn the quantity which will rise into air. 2ndly. The
influence of warmth in modifying spontaneous evaporation;
and 3rdly, the removal of the incumbent air as it becomes
saturated with moisture. Hence the advantages of a current of
air for rapidly drying a wetted surface.*

Dobereiner of Jena made the first observation on the escape
of hydrogen through a crack in a glass receiver. He did not
observe the whole phenomenon ; he ascribed it to capillary action,
which indeed it resembles in some respects. It was reserved for
Mr. Graham to clear the difficulties and give a correct interpre-
tation of the law. In repeating Dobereiner’s experiments under
different forms, he observed that hydrogen never escapes out-
wards by the fissure without a certain portion of air penetrating
inwards. Extending the experiments, and adopting an instru-
ment which would measure the rate of the interchange, it was
found that the diffusion of gases through fissures, or through
porous septa, is regulated by the same law as when they freely
communicate with each other. The relative diffusibilities are
inversely as the square roots of the densities.

It has now been determined that diffusion will take place
at different rates — though always at the same rate for the
same substance — through such porous bodies as wood, cork,
charcoal; thin slips of many granular foliated minerals, as
magnesian limestone ; through unglazed earthenware, slices of
plumbago, and Carrara marble. These porous bodies may be
regarded as a series of capillary tubes. The resistance of a

* The papers by Dr. Dalton, and those by Professor Graham, should
be consulted on this interesting subject; but, beyond all, “ Etudes sur
1’IIygrometrie,” by M. Regnault, u Annales de Chimie ” (1835), should be
studied.

381

“A MESSAGE FROM THE STARS.”

capillary tube to a gas passing through it is proportional to
the surface. (It is, of course, assumed that the ordinary con-
ditions of capillary attraction are understood. The mechanical
force which draws a fluid into a capillary tube acts upon any
gas or fluid passing through the tube.) Hence, as was ob-
served by Poiseuille, the resistance of the passage of a liquid
through a capillary tube is nearly the fourth power of the
diameter of the tube. The porous solids possess, no doubt,
a similarly reduced penetrability as that possessed by a con-
geries of capillary tubes. It must, however, be remembered,
that the times of diffusion through tubes or pores have no rela-
tion to the transpiration of the same gases. Gfraham has given
with much clearness the generally received hypothesis,* which
bears so strongly on the final result of this paper, that it is
necessary to state it in as few words as possible.

A gas is supposed to consist of solid and perfectly elastic
spherical atoms, which move in all directions, and are animated
with different degrees of velocity in different gases. Confined
in a vessel, the moving particles are constantly impinging
against its sides (should we not recognise the influence of the
force on the surface of the confining vessel attracting the
atoms?), and occasionally against each other. Owing to the
perfect elasticity of the atoms, no loss of motion arises from
such collisions. If the containing vessel be porous, then gas
is projected through the open channels by the atomic motion,
and escapes. The external air, or gas, is carried inward in the
same manner, and takes the place of the gas which leaves the
vessel. The molecular movement is accelerated by heat and
retarded by cold; the tension of the gas being increased in the
first instance and diminished in the second. This hypothesis
assumes that when the same gas is present both within and
without the vessel, and therefore in contact on both sides of the
porous plate, the movement is sustained without abatement,
molecules continuing to enter and leave in equal number,
although nothing of the kind is indicated by change of volume.
Is it not rather that the force residing on the surfaces of the
pores of the septum compels this movement in and out ? f

An interesting application of this knowledge has been made
by Mr. George F. Ansell, for the purpose of detecting fire-damp
in our coal mines. The disastrous consequences arising from
the explosions which from time to time occur in working coal,

* See “ Mathematical Physics,” by John Ilerapath (1847), and the
Memoirs of Bernoulli, Joule, Clausius, and others.

f u On the Law of the Diffusion of Gases ” (Transactions of the Boyal
Society of Edinburgh, vol. xii. p. 222). u On the Motion of Gases” (Phil.
Trans. 1846, p. 573). “ Capillary Transpiration of Gases ” (Phil. Trans.
1846, p. 591 ; and 1849, p. 349).

382

POPULAR SCIENCE REVIEW.

renders everyone acquainted with the fact that carburetted
hydrogen gas, or rather a mechanical mixture of carburetted
hydrogen, nitrogen, and carbonic acid, is constantly escaping,
in some mines, from the coal, and that mixing with a certain
quantity of atmospheric air becomes fearfully explosive. When
a flame, such as that of the Davy safety lamp, is brought
into an atmosphere containing fire-damp, its presence is in-
dicated by alterations in the condition of the flame, and the
practised eye can determine very readily the presence of the
enemy. Sometimes this carburetted hydrogen escapes from
the coal suddenly, but generally it escapes gradually from
the seam, and, not unfrequently, insidiously increases to a
dangerous degree without its being observed. To avoid this,
and under all circumstances to indicate the presence of fire-
damp, Mr. Ansell avails himself of the knowledge we possess
relative to the diffusion of gases. His apparatus takes various
forms : the most simple being a thin India-rubber balloon full
of atmospheric air, having a ligature of linen bound round its
equator to prevent its lateral expansion. This being placed in
any part of the mine, it is proposed to connect it by a wire
with any ordinary electrical bell at surface. As the balloon ex-
pands upwards by the diffusion of the carburetted hydrogen into
the air which it contains, it releases a catch, and connection being
made by a simple mechanical arrangement with the electrical
or magnetic apparatus, the bell is rung. After this signal has
been given, the Fire Damp Indicator has only to be removed
for a few minutes into good air, and it is restored to its original
state. Another form of instrument is that of the aneroid baro-
meter, a porous earthenware plate or a slice of Sicilian marble
being substituted for the brass back of the box. This little
instrument, which is only of the size of an old-fashioned watch,
is carried by the colliery viewer in his waistcoat pocket. At any
suspected place it is taken out, and the index gives the baro-
metric pressure at that depth ; this is noted ; then, if any fire-
damp is present, the index moves a certain number of degrees,
thus indicating with precision the percentage of carburetted
hydrogen present in the air.

This instrument must be regarded as one of the most beauti-
ful of the applications of science. It bears no very remote
relation in its principles, to the lamp of Davy itself, and it
supplements it in a manner which appears to promise the
possible highest utility.*

* It is important to notice here the facts j ust brought out by a well-
devised series of experiments. The safety lamps, of all varieties, are found
to be rendered unsafe by the improvements in ventilation. By increasing
the velocity of the currents in the levels of a colliery, the explosive atmo-
sphere is driven through the lamp, and the external mixture fired.

383

“A MESSAGE FROM THE STABS.”

The diffusion of liquids into each other is a remarkable
expansion of the facts discovered with regard to gases. When
two liquids of different densities, and capable of mixing, are
placed in contact, diffusion takes place ; the rate of diffusion
varying with the nature of the liquids, the temperature, and
the degree of concentration of the solutions used. The manner
in which the experiments are made is exceedingly simple. An
open phial is filled with the solution to be experimented on, say
the ammonia-sulphate of copper, and a light float placed upon its
surface. This is placed in a confectioner’s glass jar, and water
is steadily poured in so as to cover the open phial to the depth of
about an inch. The saline fluid in the bottle is now in contact
with the water in the jar, and diffusion proceeds. The ammonia
leaves the copper, and the purple solution becomes of a pale
blue colour, the volatile alkali being found diffused in the
water. The amount of salt diffused, called the diffusate or
diffusion product , is determined by chemical means. Such is
the general mode of experiment, and such the character of the
results. It is sufficient for the present purpose that the general
law is stated. etf The velocity with which a soluble salt diffuses
from a stronger into a weaker solution is proportioned to the
difference of concentration between two contiguous strata.” *

Graham has found that bodies may be divided into two
classes in relation to diffusion. One class, which are the most
diffusive, he terms crystalloids . Another class are non-crys-
tallisable, as hydrated silicic acid, hydrated alumina, and
metallic oxides of the aluminous class, when they exist in the
soluble form. Animal and vegetable extractive, gelatin, starch,
gum, &c. are of this order. Gelatin is regarded as the type of
these, and from /coWy, glue , the term colloids is adopted. This
peculiar form of aggregation is called the colloidal condition of
matter , and we find it to be a state required in all the substances
which can intervene in the processes of life. Space will not
admit, on the present occasion, of that examination of this re-
markable class of bodies which is desirable, since they play a
highly important part in natural phenomena. The colloidal is
regarded as a dynamical state of matter, while the crystalloid al
is the statical condition. Colloids are ever in a state of muta-
tion. Metastasis has been well said to be the condition of their
existence. So remarkable are the phenomena of colloidal bodies,
that those minds which have a materialistic tendency look upon
them “ as the probable primary source of the force appearing in
the phenomena of vitality.”

These colloid substances are separated from other bodies by a
process called dialysis. This will be explained in the fewest

Phil. Trans. (1862), p. 1. Journ. Ckem. So?, xv. p. 217.

384

POPULAR SCIENCE REVIEW.

words by describing an experiment. If a sheet of very thin
letter-paper, well sized with starch, and having no porosity, be
laid on the surface of water, a depression made in its centre,
and a mixed solution of cane sugar and gum arabic be poured
upon it, the sugar diffuses through the water, while the gum
remains above. The vegetable parchment or parchment paper
of De la Rue is peculiarly adapted for experiments on dialysis.

The passage of liquids through porous septa, which was .first
studied by Dutrochet, was originally designated by the corre-
lative terms endosmose and exosmose : in place of which Graham
proposes the simpler term osmose (from cocr/xos, impulsion).
Osmose has been supposed to be the unequal absorption of the
two liquids placed on either side of it by the porous septum.
Graham comes to the conclusion that osmose depends essentially
on the chemical action of one of the liquids on the septum.
The following passage, quoted from Graham’s Elements of
Chewnstry , appears to embrace all the points necessary for our
present consideration : —

“ These experiments were made partly with porous mineral
septa, partly with animal membrane. The earthenware osmo-
meter consisted of the porous cylinders employed in voltaic
batteries, about five inches in depth, surmounted by a glass tube
06 inch in diameter, attached to the mouth of the cylinder by
means of a cap of gutta percha. The cylinder was filled to the
base of the glass tube with a saline solution, and immediately
placed in a jar of distilled water ; and as the fluid within the
instrument rose during the experiment, water was added to the
jar to equalise the pressure. The rise (or fall) of the liquid
in the tube was very regular, as observed from hour to hour,
and the experiment was generally terminated in five hours.
From experiments made on solutions of every variety of soluble
substance, it appeared that the rise, or osmose, is quite insigni-
ficant with neutral organic substances in general, such as sugar,
alcohol, urea, tannin, &c. ; so likewise with neutral salts of the
earths and ordinary metals, with the chlorides and nitrates
of potassium and sodium, and with chloride of mercury. A
more sensible but still very moderate osmose is exhibited by
hydrochloric, nitric, acetic, sulphurous, citric* and tartaric acids.
These are surpassed by the stronger mineral acids, such as sul-
phuric and phosphoric, and by sulphate of potash, which are
again exceeded by salts of potash and soda possessing a decided
acid or alkaline reaction, such as binoxalate of potash, phosphate
of soda, or the carbonates of potash and soda. The highly
osmotic substances were also found to act with most advantage
in small proportions, producing, in fact, the largest osmose in
the proportion of one quarter per cent, dissolved. The same
substances are likewise always chemically active bodies, and

385

“A. MESSAGE FROM THE STARS.”

possess affinities which enable them to act on the material
of the earthenware septum. Lime and alumina were always
found in solution after osmose, and the corrosion of the septum
appeared to be a necessary condition of the flow. Septa of
other materials, such as pure carbonate of lime, gypsum, com-
pressed charcoal, and tanned sole-leather, although not deficient
in porosity, gave no osmose, apparently because they are not
chemically acted on by the saline solutions.”

Osmose appears to play an important part in the functions of
life. In osmose there is also a remarkably direct substitution
of one of the great forces of nature by its equivalent in another
force, the conversion, namely, of chemical action into mechanical
power. Viewed in this light, the osmotic injection of fluids
may, perhaps, supply the deficient link which intervenes be-
tween chemical decomposition and muscular movement.

There is yet another set of phenomena which, although not
generally associated with those which have been considered,
appear, upon closer consideration, to be intimately related to
them. These are the phenomena of catalysis , or contact
action. A sheet of perfectly clean platinum being plunged
into a mixture of oxygen and hydrogen, compels their union :
the action of this metal in a spongy state is well known, and
the action of ferments is familiar to all. Each of these are
substances which have the power of establishing chemical rela-
tions by the action of contact with considerable energy.

We have seen that gases interpenetrate in a very remarkable
manner, and that the diffusion of fluids into air, or into each
other, exhibits a force sufficiently powerful to break up strong
chemical affinities. We have observed the power of porous
bodies in compelling the passage through them of gases and
fluids ; capillarity has been briefly noticed, osmose action
described, and contact action slightly indicated.*

We have now to advance a step yet farther, and mention the
surprising passage of gases through the homogeneous substance
of a plate of fused platinum or of iron at a red heat, the dis-
covery of H. St. Claire Deville and Troost. The porosity of
graphite, of earthenware, of marble, and the action of those
substances on gases and fluids, may be regarded as fairly under-
stood. A new kind of porosity in metals is imagined, of a
greater degree of minuteness than the porosity of graphite and
earthenware ; this is an intermolecular porosity, due entirely to
dilatation. At low temperatures neither platinum nor iron
admits any passage of gas; but by the expansive agency of

* In addition, the striking Memoir by Mr. Graham, 11 On the Absorption
and Dialytic Separation of Gases by Colloid Septa ” (Phil. Trans, vol. 156,
part ii. p. 399), should be studied.

386

POPULAR. SCIENCE REVIEW.

heat the pores are opened, and these metals admit of, encourage
indeed, the diffusion of gases. “ Such a species of porosity,”
says Graham, a if it exists, may well be expected to throw a
light on the distance of solid molecules at elevated tempera-
tures when gases introduce themselves. The experiments were
essentially of the following character. A vacuum was produced
in a platinum tube placed within a porcelain tube charged with
hydrogen ; this tube was raised to a red heat, and the dense
metal then became permeable to hydrogen. The same result
was obtained with iron.

The passage of a gas through a colloid septum is preceded
by a condensation of the gas in the substance of the septum.
“ Is,” asks Mr. Graham, u a plate of ignited platinum capable,
then, of condensing and liquefying hydrogen gas?” By an
ingenious arrangement the experiment was made, and the
result proved that platinum exhibited a new property — the
power to absorb hydrogen at a red heat , and to retain that
gas at a temperature under redness for an indefinite time. It
may be allowable to speak of this phenomenon as a power to
occlude (to shut up) hydrogen, and of the result as the
occlusion of hydrogen by platinum. Experiments were made
with many other metals, and their powers of occlusion carefully
determined ; that of iron alone can be mentioned in this paper.
This was determined by first exhausting iron of any gases held
within its pores by exposing it to a high temperature, and then
cooling it gradually in hydrogen gas ; the metal absorbed and
retained this gas after cooling. The iron experimented on was
capable of holding 0*46 volume of hydrogen ; but when the
same specimen of iron was charged with carbonic oxide gas in
the same manner, it was found to be capable of taking up at a
low red heat and holding when cold 4T5 volumes of carbonic
oxide gas. This discovery cannot fail to have a bearing on the
important process of steel manufacture.

Pursuing this extraordinary line of enquiry, and obtaining at
every step new, confirmatory, and beautiful results, it was re-
solved to ascertain if the masses of matter obtained from the
atmosphere — Meteoric Stones — and which bear evidence of
having been at a very high temperature, gave any indication
of the kind of atmosphere in which they were formed.

A slice from the meteoric iron of Lenarto, which was analysed
by Wehrle, and found to be of sp. gr. 7*79, and to consist of iron
90*883, nickel 8*450, cobalt 0*665, and copper 0*002, was
obtained. This was made the subject of careful experiment,
and the Lenarto iron yielded 2*85 times its volume of gas, of
which 86 per cent, nearly was hydrogen.

“ Hydrogen has been recognised,” says Mr. Graham, “ in the
spectrum analysis of the fixed stars, by Messrs. Huggins and

387

“A MESSAGE FROM THE STARS.”

Miller. The same gas constitutes, according to the wide
researches of Father Secchi, the principal element of a numerous
class of stars, of which a Lyrse is the type. The iron of Lenarto
has no douBt come from such an atmosphere, in which hydrogen
greatly prevailed. This meteorite may be looked upon as hold-
ing within it, and bearing to us, hydrogen of the stars .

“It has been found difficult on trial to impregnate malleable,
iron with more than an equal volume of hydrogen, under the
pressure of our atmosphere. Now the meteoric iron examined
gave up about three times that amount without being fully
exhausted. The inference is, therefore, that the meteorite has
been extruded from a dense atmosphere of hydrogen gas, for
which we must look beyond the light cometary matter floating
about within the limits of the solar system.”

The series of results which are described in this paper,
though differing in their general character, have yet a strict
relation to each other. When carefully studied, it will be seen
that the sponge and the sugar sucking up water are only
modified examples of the dense metals absorbing gases. It is
by the cautious questioning of nature, and by closely inspecting
the phenomena which are constantly occurring around us, that
we advance to a knowledge of sublimer truths. Priestley’s
observation on the porosity of stoneware tubes, was the germ of
that discovery which may without any poetical exaggeration
be described as

A MESSAGE FROM THE STARS.

F F

VOL. VI. — NO. XXV.

ON THE PLANARLE OF OUR PONDS AND STREAMS.

By E. RAY LANKESTER.

THE little creatures with the structure and history of which
I hope in the following pages to make the reader ac-
quainted, as far as space and the great obscurity surrounding
them will permit, belong to a group of animals which is at
present perhaps more under discussion among zoologists than
any other — a group which stands alone in the anomalous
character of some of its organs and methods of reproduction
and development, and is remarkable at the same time for the
many points of resemblance presented by it to several other
large zoological groups. The great sub-kingdom Vermes or
Annuloida is now generally recognised as embracing five large
but subordinate classes of worm-like animals, characterised by
their general elongate and frequently jointed form ; by the
absence of jointed locomotive organs, the place of which is
frequently supplied by suckers, or by soft processes bearing
movable bristles ; by the very abundant distribution of cilia
on the surfaces of their bodies, or of their internal organs,
at one or other period of life; by the correlated, unstriped,
or faintly-banded character of their muscular fibre ; by the
primarily ventral position of their mouths ; by the absence or
terminal position of the anus ; and by the presence of a pecu-
liar vascular system (the water-vascular system), sometimes
closed, but frequently communicating with the exterior, the
fluid in which performs in part the functions of the blood of
higher animals, and in many cases contains the same colouring
matter as the red blood-corpuscles of man. They nearly all
exhibit remarkable metamorphoses in growth, and reproduce by
gemmation and fission as well as sexually ; many are internally
parasitic.

Of these five classes, the most highly organised is the group
of Ringed Worms or Annulata, comprising the marine, fresh-
water, and terrestrial bristle-bearing Worms, and the Leeches. The
class of Wheel-animalcules (Rotifera) is by some excluded from
the Vermes, but seems to fall naturally within the limits of the
sub-kingdom, connecting it with the Crustacea ; other zoologists

i VVYV^

Ib-Efen "West sc.

W West imp

PlanaricLns , etc.

Aim** _

PL AN ASIAN WORMS.

389

would include the remarkable animal Sagitta , which is, how-
ever, a transition form. The Sipunculi (Grephyrea) connect
Vermes with Echinoderms. The Round- worms (Nematelminthes,
comprising the parasitic Ascaris, Gordins , and Echinorhynchus)
and the Flat- worms (Platyelminthes, embracing the Turbellaria,
Fluke-worms, and Tape-worms) complete the list, unless we
include the Echinodermata, which are by the latest writers
regarded as forming a separate sub-kingdom of equal rank with
Vermes.* It is to the class Platyelminthes, and the order Turbel-
laria, that the Planarians belong, forming one of the two
sections into which that order is now divided. Having, from
the above brief emuneration of the groups forming the sub-
kingdom of Worms, seen what are the animals which are held
to be most akin to those we are about to study, we may de-
scend a step (or rather two steps) lower, and examine the order
Turbellaria, and then select one or two individuals of the Plana-
rian section. Before doing so, however, I must draw the reader’s

* A Tabulae View op the Classes and Oedees op Veemes.

Class I.

jj

n.

III.

)}

IV.

V

V.

Sub-kingdom : Vermes.

Annulata (Ringed-worms)

Orders : Polychceta (Marine)

Oliyochceta (Land and Fresh-water)

Discophora (Leeches)

Gephyrea (connected through the Sea-cucumbers to Echino-
dermata)

Orders : Sipunculus, 8fC.

Potifera (connected to Arthropods and Turbellaria)

Orders : Cephalotricha (Wheel-animals)

Gastero-tricha (Hairy-backed animals, Chsetonotus)

Nematelminthes (Round-worms)

Orders : Nematodes (Thread- worms, Vinegar-eels, &c.)
Gordiacea (Hair-worms)

Acanthocephali (Echinorhynchus)

Platyelminthes (Flat- worms)

Orders : Turbellaria (Planarians and Nemertians)

Trematodes (Flukes, King’s Yellow-worms)

Cestodes (Tape-worms)

Order: Turbellaria.

Sect. A. Proctucha (Nemertians) { a P10^0S^S .

v J i Without a proboscis

'With a straight intestine,
and generally a probos-

Phynchocos
Arhynchia li

Phabdoccela

„ B. Aprocta (Planarians) With an arborescent in-
testine, and no probos-
1 cis, but an expanded
t frontlet . . . . Dendroccela

There is a growing opinion amongst zoologists that the majority of the
Infusoria may be classed among Vermes near the Turbellaria. Might not the
Gregarinida also be associated with the Helminthes P

390

POPULAR SCIENCE REVIEW.

attention to the fact that there is nothing written in the
English language on these worms which will give him any fair
notion of their structure, or in any way help him to study their
generic and specific differences. The statements in handbooks
of zoology are, when correct, too wide and general to be of
much service, and recourse must be had to the German writings
of Oscar Schmidt and Max Schultze, and to the French me-
moirs by Yan Beneden, Claparede, and De Quatrefages. I have
appended a list of some of these works. The British Museum
Catalogue of Worms, which professes to give some account of
the Turbellaria, is most incorrect , and quite useless in relation
to them.

The Turbellarians are very soft, flattened animals, very long or
short, and oval in shape, with their mouths placed ventrally,
leaving a large prceoral region (prostomium of Annelids).*
Their internal organs, like those of the other Flat- worms, are
closely packed together and embedded in their muscular body-
walls, leaving no free space such as what, in Annelids, is called “ a
perivisceral cavity ; ” like the other Flat-worms, they never have
the outline of their bodies broken by the development of lateral
projecting flaps to be used as feet or paddles ; and like them,
their growth and development from the egg is complicated by
very strange metamorphoses, and by the so-called Cf alternation
of generations.” They agree with them further, though less
strikingly, in the fact that the yelk which surrounds the egg,
and on which the young animal is to feed, is in many cases
secreted by a distinct wide-spreading gland called the 66 vitella -
rium ; ” and like certain of the Flukes (Trematoda) they have a
tendency to develope regularly- shaped hard stylets or “thorns” in
connection with both their prce-oral region (proboscis) and their

* This prceoral region is an important feature in Turbellarians, and, indeed,
in most Vermes, forming the •* Kopf-lappen ” or prsestomium in Annelids,
which may he so elaborately modified into a head with appendages. In
Turbellaria, the term u prse-ganglionic region ” would he more truthful, since
the position of the oral opening of the alimentary canal varies, though it is,
probably, always in the y>o.s£-ganglionic region. I say probably, for certainty
is very hard to obtain. The proboscis was so long thought to carry the
mouth, that the true postganglionic aperture has been overlooked ; and this
may even yet prove to he the case with the genus Acmostomum, observed by
both Schmarda and Mecznikow. The large-paired ganglia, I believe, in-
variably mark off an anterior region carrying the eyes, and a posterior carry-
ing the mouth. This anterior region may he variously modified into an
expanded frontlet ( Planaria ), or a jointed and spine-hearing proboscis
( Nemertians , Alaurina, and Prostomium). This view is taken by Professor
Rolleston, and has much in its favour. But even since writing the above,
my friend Dr. McIntosh, who is preparing a work on Turbellaria for the
Ray Society, tells me that everybody is wrong about the mouth in Nemer-
tians— that the postganglionic orifice exists in a few genera only — and
hence the above homological views will he upset !

PLANARIAN WORMS.

391

generative organs (PI. XIX. figs. 3, 4, 6pe). They differ notably
from both the Trematode and Cestode Flat- worms in the complete
and permanent ciliation of the surface of their bodies, which is
one of their most characteristic features; also in having no suck-
ing discs or 'prehensile hooks, such as both these other orders pos-
sess, used for locomotion and adhesion, but only a sucker-like
mouth. In their mode of life they present the most striking
contrast to both Trematodes and Cestodes ; for whilst the mem-
bers of these orders are one and all parasitic (chiefly internally),
no Turbellarians are ever so, though they are found in the sea,
in ponds, and fresh-water streams, and in moist earth and decay-
ing wood. The integument of the Turbellaria is remarkable
not only as being densely covered with cilia, but as containing
very numerous oblong corpuscles and clear cells, some of which
have been compared to the “ nettle-cells ” possessed by the
Polyps, jelly-fish, and Nudibranchiate Molluscs. The muscular
fibre is not separate or collected into masses apart from the skin
and viscera, is in some cases faintly striated transversely, and pre-
sents, with the rest of the worm’s organs, a most singular softness
and fluidity ; so that while living most Turbellarians are almost
incredibly elastic, and when dead decompose and become a
watery mass in the course of one or two minutes. The digestive
organs are very simple : the suckqr-like mouth, placed in almost
any position (except terminally) on the ventral aspect of the
body — towards the front, centrally, or quite posteriorly — opens
into a pharynx, which is very frequently muscular and everti-
ble ; from this a straight or arborescent cavity extends through-
out the body, opening in an obscure terminal anus in the
Nemertines, but having no outlet in the Planarians. Little
glandular masses, assisting by their secretion in digestion, sur-
round the digestive tract ; and by Leydig are said to act as
kidneys also. In both Nemertians and Planarians the region
in front of the mouth is often (but not always) modified to
form what is called the proboscis, a most extraordinary organ,
which has caused the greatest differences of opinion, and has
prevented and does still prevent the proper understanding of
the anatomy of these animals. The real mouth varies so much
in its position, and is often so very backwardly placed (especially
in the Planarians), that for a long time it was thought to be a
sucker like those of the Fluke-worms, and the proboscis being
in front was thought to carry the true mouth. It is now ad-
mitted by Schmidt and Schultze (though themselves at one
time mistaken) that no Turbellaria have any sucking discs; and
that the proboscis is quite separate from the mouth, though it
may be perforated in some cases. It is probably in most cases
a prehensile appendage, but its use is very obscure. Suppose
you have a Turbellarian as I have described — with ventrally

392

POPULAR SCIENCE REVIEW.

placed month, an alimentary canal, and a large flat expanse of
body (always carrying the eyes) in front of the mouth — to form
the proboscis, you must draw out this prseoral region to a
length sometimes equal to that of the whole animal, arm it in
some cases with stylets or spines, and tuck the muscular tube
thus formed into the body, making it overlie the alimentary
canal, as the finger of a glove might be tucked into its hand.
Thus you may conceive the “ proboscis ” of Turbellarians to be
formed, with muscles so that it can be drawn in and out at
pleasure. Its doubtful use has caused various mistakes. Many
have not got it, but only an expanded or simpler modifica-
tion of the prseoral region (Dendroccel Planarians); all the
Nemertians, however, are thus armed, and many of the Rhab-
docoel Planarians. De Quatrefages regarded the proboscis of
Nemertians as the alimentary canal, no doubt reminded by it
of the eversible pharynx which the marine Annelids possess.
Oersted took it for the main organ of copulation, led into this
error by the frequent presence of little hard spines, which are
also found in the penis of some Turbellaria (Opistomum).
Leuckart was one of the first to recognise the presence of the
proboscis in the straight-gutted Planarise, in which most of all
there had been a eonfusion with the mouth (even till within
the last three or four years), and now the latest and most
reliable writers (e. g. Victor Carus) are of his opinion.

The nervous system of Turbellarians is very simple ; it con-
sists essentially of two large ganglia placed in front (often very
far in front) of the mouth, and joined by a short sort of commis-
sure, which passes always over the dorsal surface of the proboscis
when it is present. Twigs pass in various directions from these
ganglia, two principal lateral stems being often present. There
is no representative of the cord and ganglia placed beneath the
alimentary canal which is found in Annelids and Arthropods.
The eyes , which are very simple, often only pigment spots,
vary in number from two to sixteen or more ; and being always
close to the great ganglia (the equivalents of the sensory or
supra- oesophageal ganglia of higher animals), are always in
front of the mouth. In some Turbellarians a supposed audi-
tory capsule is present, and the Nemertians are peculiar in
possessing two ciliated clefts in the prseoral region, which may
be sensory. Th q vascular system is closed in adult Nemertians,
and contains red blood in some species ; in Planarians, its stems,
which are disposed laterally, communicate by two or more con-
tractile apertures with the exterior, and water is thus admitted.

We have now to speak of the generative organs and methods
of reproduction and development in these creatures ; and here a
word may be said as to the strange and anomalous position of
the mouth in relation to the fore and hind extremities, and the

PLANARIAN WORMS.

393

shapeless ovoid form of many Planarian species. They are in-
stances of what is called 66 retrograde development;”* and we
must not look at the modified shape and disposition of parts in
the adult, so much as at the history and early condition of those
parts, if we wish to see what are the true relations of the animal.
The resemblance between Nudibranchs and Planarians is, when
thus examined, found to be more apparent than real ; both live
under the same conditions, beneath rocks and stones in the
water, and exhibit identical modifications, but of very different
types. They agree chiefly in their ramified intestine, flattened
form, and nettle-cells in the skin. The relation to the Infusoria
and to the Hairy-backed Animalcules (Chaetonoti) is a much
truer one. Copious cilia, occasional stiff hairs, nematophores or
trichocysts, pulsatiug water- vessels, and parenchymatous viscera
are important characters met with in all three, while no corre-
sponding differentiating characters exist. The young larval
forms of some Turbellaria very closely resemble Infusoria and
Chsetonoti too, whilst they approach the Annelid type as well.
Turbellaria are either bisexual, or alternately male and female,
or hermaphrodite. The Nemertians are believed all to be bi-
sexual, whilst no Planarians are known to be permanently so.
The female organs are an ovary, a vitellarium, a receptaculum
seminis, and a uterus : the male organs are testes, vesiculse se-
minales, a duct and penis, armed sometimes with a style. In
the Nemertians, which are bisexual, only the essential organs
are developed ; it is in the hermaphrodite species (Planarians)
that here as elsewhere the most complex development of organs
is found, of which we shall see more hereafter.

The Turbellarians propagate either by eggs deposited and
fertilised in the water, several eggs being often deposited in one
mass of yelk (like what was observed by Dr. Carpenter in the
Dog- Whelk), or by the growth of young from internal buds or
pseud-ova, like the larvae of Cecidomya, or by transverse fission.
Both Nemertians and Planarians exhibit these three methods.
The young either develope directly, becoming similar to their
parents at once ; or they exhibit a jointed ringed structure (like
Annelids), sometimes too carrying bristles, as has been lately
shown by Mr. Alexander Agassiz, both in Planarians and Ne-
mertians, and then, as they grow older, lose their jointed appear-
ance and setae ; or the egg-hatching results in a larva (Pilidium)
which is totally unlike the parent, and from the body-wall of
which a small worm-like animal grows and separates, leaving the
bulk of the Pilidium to perish (fig. 2). This last case is very
similar to that observed by Johannes Muller in certain star-fishes.
As in the Echinoderms, so in the Turbellarians there appears to be

The Cirripedes, Lernseans, and Linguatuli are similar instances.

394

POPULAR SCIENCE REVIEW.

no rule as to the method of development ; nearly allied forms
may present the most diverse conditions, the one passing through
a larval stage, and the other developing directly in the most
capricious manner (figs. 9, 13).

And now that we have reviewed the group of Turbellarians
generally, we have to speak of one of its two divisions. Leaving
for a future period the long, almost snake-like Nemertians, we
pass to the small flattened Planarians, and have to attempt to
make some of their commonest fresh-water forms known. The
Planarians or Aproctous (without an anus) Turbellarians are
found on the sea-shore, in fresh waters, and in the earth. The
marine species of our own coasts are not abundant, but occur on
most rocky shores. Some of the fresh-water species occur in
almost every pond and ditch, whilst one earth-living species is
known in Europe, and may be expected to occur in Britain. It
is quite impossible to give a list or descriptions of the British
species, as no one knows how many there are, so little attention
has been paid to them. I think, however, a diagnosis of the
genera which may be expected to occur in ponds or streams,
will be useful, and a brief description of one or two fresh-water
species, which, though much smaller and far less brilliantly
coloured # than the marine forms, are more readily accessible.
After examining these, the reader will be able readily to trace
the anatomy of others for himself. On account of the homo-
logies of the proboscis, mouth, and prseganglionic region in
Planarians, at present so greatly needing further investigation,
the genera as they now stand are in many cases based upon
error. Even in Victor Cams’ Handbuch der Zoologie (1863),
I find the confusion of mouth and proboscis maintained in the
generic names, though in the chapter on anatomy it is re-
nounced. The value of the u proboscis ” as a classificatory cha-
racter is rendered doubtful by the fact that when absent or
rudimentary in the adult, it may* be present in the young state.
Duges and Oscar Schmidt have both made generic names in-
tended to indicate the position of the mouth, but the meaning
of these names must now be disregarded. F or the determina-
tion of species , the reader must do the best he can with the
papers of Duges and Schmidt ; they are by no means definite,
and anyone who will devote a few years to the study of our
British species will do valuable work.

* Some fresh-water forms were stated "by Max Schultze to contain chloro-
phyl as a colouring matter, as also Hydra and Stentor. This I have lately
verified by spectrum-analysis.

PLANARIAN WORMS.

395

PlAXARIAXS, OR TeRBELLARIA ApROCTA.

Intestine without a posterior opening . — Hermaphrodite.

Sect. A. — Hhdb docoda. Intestine a straight sac. Usually two eyes on
the ganglia. Body generally of an elongate oval form.

(a) With a muscular pharynx, usually exsertile.

Genus 1. Prseganglionie region in the form of a conical muscular pro-
boscis. Mouth circular. — Prostomem, Duges ( Rhynchopro -
bolus, Acmostomum , Schmarda).

„ 2. Prseganglionie region well developed, broad and blunt. Pharynx

tub-shaped. — Vortex, Ehr. ( Derostomum of Duges).

„ 3. Prseganglionie region not muscular, and reduced in size. Mouth

circular, near the centre of the body. — Mesostohem, Duges
( Strongylostomum Typhloplana of Oersted).

„ 4. Prseganglionie region small. One eye. Body long and worm-

like. Mouth central. (Marine.) — Moxocelis, Oerst.

„ 5. Prseganglionie region reduced to a minimum. No eyes. Mouth

towards the posterior end of the body. — Opistomem, 0.
Schm.

(0) A muscular pharynx is ivanting.

,, 6. Mouth an oval opening, placed lengthwise near the fore end.

Prseganglionie region small and flat. — Macrostomexi, Oerst.

„ 7. As the last, but mouth a long slit. — Orthostomem, 0. Schm.

„ 8. Mouth a cross slit. No eyes. (Marine.) — Coxvoleta, Oerst.

„ 9. Prseganglionie region pinched off as a kind of head, carrying

two tentacular processes. Mouth round, behind the eyes. —
Vorticeros, 0. Schm.

Sect. B. — Dendroccda. Intestine an arborescent or multiramose cavity.
Eyes often numerous. Prseganglionie region broad and flat, often tentacular,
forming a frontlet. Body flat, broad.

(a) Digonopora. With double genital openings. All marine ; often bril-
liantly coloured.

(p) Monogonopora. With a single genital opening. Nearly all fresh-
water or terrestrial. All with a large muscular pharynx.

Genus 1. Body oblong, flat. Mouth subcentral. Frontlet* three-cornered,
or with tentacula-like comers. Eyes two, with lenses. —
Plaxaria ( Dendrocodum ).

„ 2. Frontlet small. Eyes many. The rest as Planaria. — Polycelis,

Ehr. (not De Quatrefages).

„ 3. Body elongate and vermiform, often brilliantly coloured.

Prseganglionie region (frontlet) large and broad, sometimes
expanded as a hammer-head. Animals all terrestrial. —
Geoplaxa.

This synopsis of genera is no doubt in many ways imperfect,
but I believe it gives a fair view of the principal divisions of the
fresh-water forms. The Rhabdocoels are minute, and abound

* This name is proposed by Professor Rolleston for the prsegangiionic
region of Dendroccels.

396

POPULAK SCIENCE REVIEW.

in most ponds and streamlets. They are best observed first
with a lens — in a bottle of the water containing them, and then
afterwards picked up in a tube drawn out to a fine opening.
The commonest forms belong to the genera Mesostomum,
Vortex, and Prostomum (figs. 5, 6, 7, 8). The species are at
present quite undefined.

The marine Dendrocoels I have omitted. They are very
beautiful in colour and graceful in form — many species are
figured in the memoirs by De Quatrefages and Claparede (fig. 14).
The commonest little black fresh- water Planaria belongs to the
genus Poly cells, having many eyes ; species of true Planaria are,
however, abundant enough with them (figs. 17, 18). All these
Dendrocoels are much larger than the Rhabdocoel forms, being
often more than half an inch in length, and very conspicuous by
their dark colours. Duges, in his memoirs ( 1828-1830), de-
scribes several species, and also the wonderful power of repara-
tion of injuries they possess. By slicing them with scissors,
individuals may be produced with two heads or two tails, and
otherwise modified. It is Oscar Schmidt, however, who within
the last seven years has described their anatomy.

Duges found the very remarkable Geoplana terrestris (fig. 16)
in France in Languedoc, and it ought to occur in England.
Will the readers of the Popular Science Review hunt it out ?

I now propose to speak of the anatomy of Opistomum , a
Rhabdocoel, and Polycelis , a Dendrocoel, in greater detail.

Having caught sight of an Opistomum (fig. 5) or Me-
sostomum (fig. 7) swimming over the surface of a bottle of
pond-water, you may conveniently catch the minute creature by
making use of a dipping tube with a fine orifice, and then place
it on a compressorium or under a glass cover. The first thing
to note is the ciliation of the whole surface of the body,
excepting the sucker-like mouth, which in Opistomum will be
readily seen lying very far back near the posterior extremity
(fig. 6). A little closer examination of the clear transparent
skin will disclose the presence of very numerous clear ob-
long corpuscles, which are scattered all over it, and belong to
that group of organs which is represented by the “ trichocysts ” *
of Infusoria and the nettle-cells of Polyps and other animals.

Examining now the digestive organs, it is not difficult to trace
the large cylindrical and muscular pharynx (ph) opening from the
mouth and leading into a capacious but simple sac which has no
other opening — this is the stomach and intestine both. Coloured
granular masses are crowded on its surface, and some of these,
perhaps, act as a sort of bile-forming organ. Overlying this
stomach are other masses of cells and muscular fibres, of the

* See Allman, Jour. Micros. Sci. (1855), vol. iii. p. 177.

PLANARIAN WORMS.

397

simplest form, which form a body-wall of unlimited powers of
movement. The large accumulations of cellular masses belong
to the generative system, and may often obscure other parts.
Quite in front is the pair of nervous ganglia (g) which send out
their minute and invisible branches in all directions. In Opi-
stomum there are no eyes to guide one in finding the ganglia, and
hence the task is not so easy as in Mesostomum , Prostomum,
and Vortex (figs. 7, 6, 8), in which the eyes lie just in front of
the ganglia ; nor is there any expanse in front of the gan-
glia— the “proganglionic region” is reduced to the smallest
amount. Winding in and out among the contents of the body,
sending out branches here and there, you will observe two
indistinct tubes, running lengthwise, one on each side of the
body ( nn ). These vessels are the main stems of the water-
vascular system, and may be traced to two pores or openings
placed far back on the ventral surface. Their internal surface
is ciliated, but they are not contractile.

The reproductive organs are the most curious and most im-
portant points to make out in the straight-gutted Planarians ;
and, indeed, in the Dendrocoels also they have been used as
specific and generic characters. Although hermaphrodite, Opi-
stomum , like other Rhabdoccels, has only one outlet for the
ova and the seed. The Dendroccel Planarians are well divided
into two groups, according as the generative opening is single or
double (a male and female); and Elias Mecznikow* thinks that
this may some day be done with the Rhabdoccels. The testes
(fig. 5 t , f) in Opistomum form a large sac on each side of the
body, opening into a middle seminal vesicle placed quite pos-
teriorly ; leading from this is the very long coiled penis, which is
covered with spines. In Prostomum (fig. 6pe ) there are in this
position large and hard stylets, like the dart ” of the common
snail, which some writers have considered as belonging to the
male generative apparatus, and others have regarded as stinging
organs. The ovaries ( ov ) are seen nearer the genital pore than the
testes , and are smaller bodies ; they open into a cavity (ut) which
has been called the uterus; into this also open two large
glandular masses (vi) called <c vitellaria,” which in most animals
form part of the ovary, but are here separated as distinct glands,
as in many molluscs. They secrete the greater mass of the yelk,
or food-yelk, as opposed to the essential formative part of the
ovum, which is developed in the ovary ; just as in birds the
food-yelk is secreted by the Graafian follicle. Besides these two
glands, a cavity which receives the sperm during copulation ( rs )
opens into the uterus, and it is by this means that in the
uterus the contact of the ova and spermatozoa is effected. The

Wiegmann’s Archiv, 1865.

398

POPULAR SCIENCE REVIEW.

uterus itself communicates with the exterior by the same open
cavity or pore as does the penis. This pore is much larger and
more important in the Dendrocoels than in Opistomum and
its allies. The exact anatomy of the uterus and its connected
glands is still doubtful, according to Mecznikow, although most
carefully investigated by Schultze. The reader, perhaps, may
be induced to try to place it beyond a doubt.

We pass on now to Polycelis. It is to this genus of the Plana-
rians with tree-like intestines, that our common little black
Planaria ( Polycelis nigra) belongs ; other dark-brown and
blackish species are not uncommon about the same size or a
little larger (to the third of an inch), and belong, some to the
genus Planaria , some to the genus Polycelis as defined above,
and are distinguished to a great extent by the shape of their
frontlets. Some species (PI. lactea, &c.) are to be got which
are quite white and clear, and are admirably adapted for study.

The same ciliation of the surface, and the same, though more
elaborate, corpuscles in the skin, are to be noticed in Polycelis
as in Opistomum. The subcutaneous muscular system has
even a more extraordinary development, for the animals flow
or slip over a surface more like a liquid drop on a piece of glass
than living creatures. The mouth (fig. 12) in our figure of the
digestive organs of Planaria lactea is, as in Polycelis, near the
centre, and leads into a large, exsertile, suctorial pharynx ; this,
according to the observations of Duges, the animal protrudes,
and firmly fixes to small worms, insects, larvae, or whatever may
be its prey, and through it sucks their juices. The beautifully
dendroid character of the intestine is well seen in the figure.
The nervous system, which in fig. 10 is illustrated by that of
Polycelis cornuta , is similar to that of Ehabdocoels, but its
branches are more obvious. The water- vascular stems are
obscure, but Max Schultze says he has seen them in PI. torva ,
and so we may expect them in Polycelis. The generative
organs are highly developed in Polycelis and its allies. In
fig. 21, the penis, uterus, and ends of the sperm-ducts of Poly-
celis nigra are drawn. The penis is covered with spines, and
varies curiously in shape in different forms. In fig. 11, the
genitalia and pharynx of Planaria torva are drawn according
to Schultze. Polycelis differs from this only in one important
matter, and that is the absence of the little gland or sup-
posed spermatophore ( h ). As in Ehabdocoels, we have vitel-
laria, ovaries, and a uterus, spermatheca, testes, seminal vesi-
cles, and a penis, as also a very large cavity or vestibule
into which they all open. Oscar Schmidt has written some very
beautiful papers on these organs in Planaria and Polycelis
(Zeitsch. fur Wiss. Zool. bd. x. xi.), and has shown how
their arrangement differs in different species.

PLANARIAN WORMS.

399

Schmidt has also in PI. cornuta described what he says
may be spinarets, like those of a spider, but he doubts about
them. I think it important to mention that Daly ell, in his
“ Power of the Creator,” notices two or three species of Plana-
rians as apparently spinning and hanging by threads.

And now, before ending, I may urge those who can, to study
and draw carefully any Planarians they may find, as material
is greatly needed for%a complete history of Fresh-water Plan arise.
The ponds on Hampstead Heath and the wonderful old pond at
the Surrey Hardens (St. Thomas’s Hospital) I have found to be
excellent hunting grounds.

Bibliography.

Duges (for habits and rough drawings of species). Ann. Sc. Natur. tome
15, tome 21.

Schmidt, Osc. (for descriptions and figures of genera of fresh- water Rhab-
docoels). Die rhabdocoelen Strudelwurmer . Jena, 1848. Wien. Akad.
Proc. bd. xxiii.— (For anatomy of Dendrocoels). Siebold und Kol-
liker’s Zeitschr., bd. x. bd. xi.

Schultze. Zur Naturgesch. der Turbellarien. Greifswald. 1851.
Quatrefages (Marine Planarians and Nemertians). Ann. Sc. Nat. tom. 21,
3rd ser.

Claparede (Marine larvae, &c.). Geneva Academy. 1863.

Mecznikow. Wiegmann’s Archiv (1865), and Ann. Nat. Hist. (1866).

DESCRIPTION OF PLATE XIX.

Diagram of the anterior half of a Nemertian worm : pr , proboscis ;
p, preganglionic region ; c, ciliated cleft ; y, nerve ganglion ;
m, ventrally-placed mouth ; gn, generative gland ; i, intestinal
canal. Five times the natural size.

Pilidium gyrans : a , rudiment of young Nemertid. Greatly
magnified.

Style-apparatus of the proboscis of a Nemertian.

Anterior part of a Cercaria (from the Lymnceus stagnalis ), to show
the striped integument. The mouth m, and the stylet s, placed
in the prseoral or prae ganglionic region.

Opistomum pallidum , Schmidt (copied from Schultze) : g, nerve
ganglion ; o, mouth ; ph, pharynx ; tt, testes ; df, vasa deferentia ;
vs, seminal vesicle ; pe , penis j G, genital opening ; va, vagina ;
rs, receptacle of semen ; or, ovary j vi, yelk gland •, ut, uterus,
with two eggs.

Prostomum lineare , Ehr. (after Schultze) : pr, proboscis ; g, nerve
ganglion ; m, mouth ; ph, pharynx ; t, testes ; vi, yelk gland ;
vs, vesicle for semen ; pe, penis (with a hard dart) ; rs, recep-
tacle of semen; ov, ovary; x, uterus (according to Meczni-
kow) ; n n, water- vessels and their openings.

Fig. 1.

6.

400

POPULAR SCIENCE REVIEW.

Fig.

»

)>

n

V
))

V
))

V
»

V

7. Mesostomum sp., observed at Hampstead : p, praeganglionic region,

showing a tendency to become muscular and proboscidiform ;

g , nerve ganglion ; m, moutb ; n n, water- vessels.

8. Vortex (of Scbmidt) sp., observed at Hampstead : g, nerve gan-

glion ; m, moutb ; gn, genital orifice.

9. Microscopic larva of a marine Turbellarian ( Alaurind ), observed

by Claparede.

10. Anterior portion of Poly cells cornuta, after Oscar Scbmidt: p,

praeganglionic region ; g, nerve ganglion ; ov, ovary ; i, part of
tbe ramifying intestine ; e e, eyes.

11. Planaria torva (Miiller) : g, nerve ganglion ; m, moutb ; ph,

pharynx ; ov ov, ovaries ; 1 1, testes ; df, efferent ducts ; pe, penis ;

h, supposed spermatopborej x, uterus (P) ; va, vagina; gn, genital
opening.

12. Planaria lactea , showing tbe Dendroccel character of tbe intestine :

m, moutb.

13. Microscopic larva of a marine Dendrocoel Planarian, after Alex-

ander Agassiz.

14. Eurylepta vittata, a marine Dendrocoel ; nat. size.

15. Bipalium, an eartb-planarian from Ceylon ; nat. size.

16. Geoplana terrestris, after Duges ; nat. size.

17. Planaria gonocephala, after Dug6s ; nat. size.

18. Planaria tremellaris, after Duges ; nat. size.

19. Planaria cceca, after Duges ; nat. size.

20. Planaria cut so as to produce two beads, after Duges.

21. Part of tbe genitalia of Poly cells nigra : m, moutb; df, seminal

efferent ducts ; pe, penis, with prickles ; gn, genital vestibule ;
x, supposed uterus (see fig. 11).

401

VENTILATION AND VENTILATORS.
By THE EDITOR.

IF we may be permitted to define cant as the current expression
of unintentional insincerity, we believe that there is no species
of cant more general than that which people talk about ventila-
tion. Go where we may, whether into the houses of the wealthy
or into the miserable dwellings of the poor, we hear the same
cry about ventilation and its advantages ; but in no cases, or at
least in few, do we see any reason to think the cry a genuine one.
How many people tell us of the healthy influence of pure fresh
air, but how few ever take proper steps to introduce it into
their houses ! How seldom do we see anything like a rational
system of ventilation in public buildings ; and where are the
private dwellings in which vitiated breathing-air is not abun-
dantly present ? It is not our intention, in the observations we
are about to make, to dwell upon the elementary facts that human
beings contaminate air by the exhalations from their lungs, and
that the respiration of such air is eminently injurious to health.
These have already been fully and forcibly pointed out by Dr.
Edwin Lankester.* Indeed, we think it is now pretty generally
admitted that the influence of a greater proportion of carbonic
acid in a breathing atmosphere than that of *6 per 1000 is both
adverse to comfort and obnoxious to health. We purpose,
therefore, to lay before our readers, as clearly and withal as
briefly as possible, the principles on which ventilation should be
conducted, and to describe the more important methods by
which such thorough ventilation as can be adopted may be
achieved.

At the outset we may state, in very general terms, that the
word ventilation simply expresses the passage in and out of air.
The regulation of this inlet and outlet, in such a manner as to
be least productive of discomfort and disease, is one of the
highest aims of hygiene. We may add, too, that it is by far its
most difficult problem. In an ordinary room it is clear that air
is constantly entering and leaving by some of the apertures in

* See Popular Science Review , vol. iii. p. 6.

402

POPULAR SCIENCE REVIEW.

the doors and windows, and through the chimneys. This may
be easily proved, experimentally, by holding a lighted taper near
any of these points. But it is equally true a priori. It happens
generally that the inlet is not sufficient to remove the carbonic
acid rapidly enough to reduce its proportions to the standard
above given. The question then arises, How are the con-
ditions necessary for the production of this standard ascertained ?
This is exactly what we propose to discuss, for it supplies the
key to the whole principle of ventilation. There is the less
difficulty in popularising this subject, that of late it has received
the studious attention of some of our ablest chemists and
sanitarians, who have laid their, opinions before the public.*
Before, however, we plunge in medias res of ventilation, we
must ask the reader to remember that the physical law known
as that of “ mutual diffusion,” plays an important part in all
questions relating to the mixture of different gases, such as
of oxygen, nitrogen, and carbonic acid, which make up our
atmosphere. By virtue of this law, it occurs that two gases
when brought together, no matter what their relative weights,
become thoroughly mixed together, in proportions which are
stated as being inversely as the square roots of their densities.
Carbonic acid is a gas so heavy that it may be decanted from
one vessel into another ; and hydrogen is so light that a balloon
filled with it ascends, as we all know, into the air. Yet if a
vessel filled with the latter be inverted over one containing
the former, and a piece of membrane be placed between the
mouths of the two, it will be found that, after a while, some
of the carbonic acid has ascended into the upper vessel, and
the hydrogen has descended into the lower one, and mingled
with the carbonic acid. A mixture will be thus formed in both
vessels. It is the same in nature. Animals are perpetually
exhaling carbonic acid into the atmosphere, and were it not
for this wonderful property of . “ diffusion,” a stratum of foul
air would lie over the earth, and would possibly extinguish
animal existence. This, then, is one of the great facts of venti-
lation, as it is in nature. There is, however, another point in
which natural ventilation is superior to all other forms — viz., that
plants use up the carbonic acid as food, setting free the oxygen
which helped to form it, and thus, as it were, manufacturing air
for the use of animals. The law of diffusion the reader must
consider as the starting-point in all ventilation problems. With
this law as his guide, he is prepared for the consideration

* See Papers by Dr. A. Smith, F.R.S., Dr. E. Smith, F.R.S., Professor
Donkin, F.R.S., and Dr. Parkes, F.R.S., in the “Report of the Committee
appointed to consider the Cubic Space of Metropolitan Workhouses.” Pre-
sented to both Houses of Parliament, 1867.

VENTILATION AND YENTILATOBS.

403

of the other principles of this branch of hygiene. Concerning
the extent of its operation, however, the student encounters
his first difficulty, for it must be confessed that all writers
are not agreed as to whether, in the case of the atmosphere
of dwelling-rooms, the diffusion which takes place is com-
plete or partial. Decision in regard to this is “ a consum-
mation most devoutly to be desired,” for in its absence we
are driven to accept one of two alternatives. For instance, it
being known how much aii* one individual vitiates per minute
in breathing, if it were admitted that complete diffusion occurs,
we could calculate with tolerable precision what quantity of
fresh air should be introduced per minute into a room of known
capacity, in order to enable healthy respiration to take place.
But if we admit that the diffusion is only partial, and that
atmospheric currents may sweep away the foul air as it issues
from the lungs, and before it has had time to mingle thoroughly
with the air of the chamber, then our basis of calculation is
so uncertain and variable that nothing short of practical demon-
stration can give us a clue to the quantity of air which it is
necessary to supply for the purposes of health. These may
not at first sight appear serious objections, but it must be
borne in mind that the end of all efficient ventilation is
the removal of exactly so much vitiated air as will leave the
remaining atmosphere fit for healthy respiration, and no more
than this, and the achievement of this without inconvenience or
discomfort. It follows, then, that if any system of ventilation be
based on erroneous calculation, either too much or too little air
will be introduced into the apartment ventilated, and thus the
inmates will either be supplied with impure air or be exposed to
unpleasant draughts. The necessity for the establishment of a
rigid elementary principle, as the starting-point of all systems
of ventilation, is therefore obvious.

It may be as well, before going further into the subject, to
lay before the reader the views of two able writers, whose
opinions are somewhat materially in conflict. Dr. Angus Smith
and Dr. Parkes, of Netley, have both devoted much time and
skill to the investigation of the conditions of ventilation, but
they come to very different conclusions as to the question, Gan
a small room be more thoroughly ventilated with a given sup-
ply of air than a large one ? Dr. Smith advocates the em-
ployment of the small room under the circumstances referred
to. He says : “ Let us imagine a man in a small box, or having
his head in a small box, in which he would be supplied with
air sufficient for an inhalation as often as he required it. The
total amount would be about 12 to 20 cubic feet in an hour.
The stream of air is so rapid that the impure is removed as
rapidly as the pure is supplied. Put the same man in the
VOL. VI. — NO. XXV. G G

404

POPULAR SCIENCE REVIEW.

space of 500 cubic feet of air, and supply him with the same
amount of air as he received in the small box, and it becomes
rapidly noxious. We see, then, that the mode of supplying the
air is one of the most important points. In a very small space
a man may find a very little air to be enough by rapid venti-
lation. In a considerable space a man may find himself un-
comfortable from the want of ventilation, even although the
amount of air supplied by ventilation is many times greater
than in the small space.” No further quotation is necessary to
show the nature of Dr. Smith’s views. The writer evidently be-
lieves that in small spaces the heated air from the lungs ascends
from the mouth, and is borne away by currents before it has had
time to mingle intimately with the air of the chamber. This is,
in fact, nothing less than a denial that thorough diffusion takes
place. To accept Dr. Smith’s views, we must admit a partial
diffusion only, and we fancy that the author’s system must admit
draughts. Let us see, then, what Dr. Parkes has got to say in
reply, for we could not state the argument against Dr. Smith
in a more concise or intelligible form than it has been expressed
by the distinguished Professor of Hygiene in the Army Medical
School. Dr. Parkes first points out that the man in the box
must not be supposed to draw in the air he requires from a
supply-pipe, and to simply breathe it out by an exit- tube. If
such were the case, the experiment would be equivalent to a man
breathing in the open air ; but evidently this is not what Dr.
Smith supposed. The man’s head being once more placed in
the box. Dr. Parkes supplies him with 16 cubic feet of air for
an hour, and he thus describes the result : “ At his first inspi-
ration the man draws in 30 cubic inches of air from the box-air
(which is at once replaced from outside), and then expels it, so
that 30 cubic inches pass out of the box. These 30 cubic inches
will be partly derived from the air of the box which has not
gone into the lungs, and partly from the air from the lungs; con-
sequently all the air from the lungs will not pass out , but some
will remain in the box and render the air there slightly impure.

... At the next inspiration 30 cubic inches are drawn into
the lungs [the void being replaced from outside], and are then
breathed out, and simultaneously 30 cubic inches of air pass
out from the box. The 30 cubic inches which pass out are
again made up of a mixture of the box-air and the lung-air.
It is evident that the box-air must at every expiration become
more and more impure, although at the end of the hour the 16
cubic feet stated by Dr. Angus Smith to be sufficient will have
been supplied.” We cannot afford space for further extract,
but we may mention that Dr. Parkes makes a very simple
arithmetical calculation of the quantity of carbonic acid accu-
mulated in the box at the end of the hour, and shows most

VENTILATION AND VENTILATORS.

405

conclusively that long before this time the man would commence
to be poisoned with his carbonic acid alone, to cc say nothing of
the organic matter evolved from his lungs.

It seems to us that in all respects Dr. Parkes’ explanation of
the state of things in the supposititious case selected by Dr.
Smith, is in accordance with theory and experience. However
much we may be disposed to admit that complete diffusion does
not occur, we cannot deny that there is considerable admixture
of the gases, and this is adequate to bring in a verdict for Dr.
Parkes. We see, then, that in calculating the quantity of air
to be supplied to an individual, we must not be guided alone
by the number of cubic feet of pure air consumed per
hour. We must take diffusion into account. The proposition
may be fairly laid down, however startling it may appear, that
in order to make the conditions of respiration in a room as
healthy as they are in the open air, the whole air of the room
should be renewed at each respiration . Put this would not be
possible, for in order to do so, we should have to produce a
series of air-currents which would be perfectly intolerable. Our
object, then, must be to prevent the vitiation of the air beyond
a point which can be borne without injury to health. In the
air which we breathe out of doors, we find that there is *4
part of carbonic acid in 1000 parts; and we know from expe-
rience that an atmosphere which contains *6 per 1000 of carbonic
acid may be breathed with impunity. Our aim, then, must be —
admitting diffusion — to supply such a quantity of air per hour
as will keep down the pollution of the air to this standard.
Here, again, arises the question, Can this be effected more easily
in a small room than in a large one ? This is a problem of some
gravity ; and, in our opinion, its only correct solution is that
given by a mathematician — Professor Donkin, F.R.S. On this
point we differ from both Dr. Smith and Professor Parkes. The
former would, of course, allege that the smaller space is the more
convenient ; the latter contends that a larger apartment is more
easily ventilated. According as we view the matter from dif-
ferent standpoints, each is right, though both, in our opinion,
are in some respects in error. In a small room, with a very
powerful out-draught, the quantity of air demanded per minute
might be smaller than that demanded for a larger one. Again,
in a large room we have the advantage of a large supply of air
to dilute the poisonous gas. A little reflection, however, will
show that in both cases, unless the increasing impurity be kept
under, the rooms will, at a certain period, become uninhabitable.
This, we think, is a point which has been overlooked by Dr.
Parkes. Those who read Professor Donkin’s observations on
the subject can decide whether we are right or not ; but we con-
fess that we cannot see what the size of the room has to do

406

POPULAR SCIENCE REVIEW.

with the quantity of air to he supplied per hour. It is a matter
for arithmetical calculation, but it seems to us by no means
difficult to show that, whether the room he large or small (assu-
ming it to be constantly in use), the quantity of air introduced
must be the same in order to reduce its atmosphere to the
standard demanded by hygiene. The quantity of carbonic
acid developed per hour is a constant quantity ; and as it diffuses
itself thoroughly through the room, it is evident that the quan-
tity of air required to dilute it to innocuity must also be definite.
Of course, in applying this in practice, it is necessary to assume
that the room will ultimately arrive at a certain degree of pol-
lution by carbonic acid. And this is just the particular which
shows that if the room he not constantly occupied, Dr. Parkes’
view is correct. It takes a much shorter time to effect the
pollution of the air to the required standard in a small room
than in a large one. Hence in a room of great capacity the air
might not become impure in the few hours during which it was
in occupation. In hospitals and suchlike institutions it would,
of course, be different. We cannot afford space to go into the
calculation by which Professor Donkin arrives at his conclusion,
hut we may state that he believes 3,000 cubic feet of air to be
the minimum which should be supplied per hour to each indi-
vidual; this being, of course, independent of the size of the
room. The question of size, however, cannot he passed over as
unimportant, for the simple reason that in rooms of small size
the necessary supply could not be introduced without the
employment of strong currents of air, which would he not only
troublesome, but might be even dangerous to health. But it
must never he forgotten, that though a smaller supply of air
may suffice to ventilate a larger than a smaller room for a
short space of time, at a certain period, sooner or later according
to the capacity of the apartment, the same quantity of air per
hour must be supplied to both, and this must invariably be
3,000 cubic feet per hour for each person present.

Having arrived at the determination of the principle which
should guide us in ventilation, and having established a rule
for the quantity of air which must be introduced per head per
hour into a room constantly occupied, we can now proceed
with the second part of our enquiry — the methods by which the
introduction of fresh air is effected. This part of our subject
is of the highest importance, and, we might add, also of the
greatest difficulty. It is obvious that in all arrangements for
ventilating an apartment, it is the same thing whether we pro-
vide for the removal of a definite amount of foul air, or for
the introduction of the same quantity of fresh. “ Nature
abhors a vacuum,” and the elimination of the consumed or
partially consumed air involves the introduction of an equivalent

VENTILATION AND YENTILATOES.

407

volume of the outer atmosphere. It is, however, sometimes con-
venient to distinguish the two modes, especially in describing
mechanical arrangements, and hence we find it usual to designate
the “ removal” the vacuum method, and the “ introduction ” the
plenum mode. It may, at first sight, appear to the reader that
the introduction of 3,000 cubic feet per head per hour into any
ordinary room would be attended with serious inconvenience ;
but practically it is not found so. Indeed, if we take any
room provided with a chimney and fire, we find that the quan-
tity of air introduced per hour is much greater than we should
have supposed. By means of a sort of scientific windmill,
technically styled an anemometer , we are enabled (by counting its
revolutions per minute) to estimate the velocity of currents of
air ; and then, the calibre of the shaft through which the
draught passes being known, we obtain, by a little calculation,
the exact quantity of air per minute supplied by any aperture.
We mention this here because the anemometer has been
placed in the chimney of an ordinary room when the fire was
burning, and its revolutions showed beyond all question that
1,004 cubic feet of air per minuxe, or upwards of 60,000 cubic
feet per hour, passed out of the room, and must have been
replaced by an equal amount which entered by the usual
channels. Thus, in this case at least twenty people might have
been supplied with a healthy atmosphere, provided the air was
not heated to too high a point. It is customary with writers
on ventilation to speak of natural and artificial systems of ven-
tilation ; but as in most cases a fire exists in what is termed the
natural arrangement, the division is more empirical than cor-
rect. Without, then, employing this distinction, let us consider
the condition of one of our sitting-rooms in winter. The fire
burns brightly, and, as a consequence, several thousand cubic
feet of air are hourly drawn up the chimney. Whence comes
the air to replace this loss? The chinks in the door and windows
are constantly admitting a stream of cold air, and thus ventila-
tion is effected at the expense of draughts, which produce
chilled feet, catarrhs, and so forth. Still, ventilation takes
place. We are now supposing that the lamps have not been
lighted ; and we think everyone’s experience will show that most
rooms in which a fire burns well are tolerably well ventilated
( quoad the amount of air) till, say, the gas is lit. The moment
the chandelier comes into operation (supposing it to contain five
ordinary fish-tail burners), the state of things is changed, and in
the course of half-an-hour or so, this change becomes distress-
ingly perceptible. Why ? — People never ask themselves this
question. Because more than twenty additional pairs of lungs
have begun to use up the air, each burner in use being equiva-
lent to nearly five persons. This is the great defect of our modern

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dwellings. In olden times ventilation must have been far better
than it is nowadays, when our demand for light is followed by
so large a consumption of our breathing-air. And why, again, is
there this distinction between the fire and the gas ? The fire uses
up air, but it also acts on the vacuum principle, and produces a

draught of fresh air in the room ;
but the gas does n ot. What, then,
is the remedy ? Convert the gas
into a fire, provide it with a
chimney to convey out the pro-
ducts of combustion, and compel
it thus to ventilate the room as
thoroughly as the fire does.
Many methods of doing this
have been suggested, but the
one which has been found most
satisfactory in operation, and of
which we ourselves can speak in
high terms of praise, is that
which has been invented by Mr.
Eicketts, and is known as the
Ventilating Globe Light. We
have only one fault to find with
it, and that is its costliness ;
but we confess we cannot see
how, under existing conditions,
it could be sold at a cheaper
rate. The accompanying dia-
gram explains its construction.
It consists of an Argand burner,
enclosed in a globe of large pro-
portions, whose only aperture for
admission of air is at the top. A shows the burner and
chimney in section, and the letters D D and the arrows
indicate the mode of admission of air from the room. The gas-
pipe is enclosed in a tube of larger dimensions, B B, which
passes from, the portion of the globe immediately above the
chimney of the burner to the ceiling of the room. Here it
communicates with a shaft, which passes under the joists of the
room above, and discharges the foul air into the chimney.
The letters C C indicate a funnel, whose mouth communicates
also with a portion of the shaft, and which draws off the heated
air of the room, throwing it — as in the case of the products of
combustion from the burner — into the chimney. Thus far, Mr.
Eicketts5 contrivance is theoretically excellent. Our examination
of it in these respects confirms the inventor’s anticipations ; it
not only carries off the products of its own combustion through

VENTILATING GLOBE-LIGHT.

VENTILATION AND VENTILATORS.

409

the outlet tube, but the funnel removes much of the heated
air of the room — tobacco-smoke, vapour, and such like, passing
up with great rapidity through the apertures in the “ ceiling-
flower.” It will be observed that the diagram shows a pair of tubes
external to the funnel and communicating with an inlet tube,
the arrows here indicating a passage of air inwards. This is an
addition to Mr. Ricketts’ lamp, which was suggested by Mr. J.
P. Seddon, Hon. Secretary to the Royal Institute of British
Architects, and which strikes us as more ingenious than effi-
cient. Its object is the introduction of cool fresh air from
without, thus converting the lamp into an apparatus for venti-
lating perfectly closed rooms. It is only fair to say that we
have not gone carefully into the examination of this addition ;
but our observations, so far as they went, tended to prove
its utter inutility ; indeed, so far as we could perceive, it acted
more as an outlet than anything else ; but on this point we
are desirous of further experience. In every other particular,
Mr. Ricketts’ plan seems to meet a great want ; and we doubt
whether in winter (when fires are used) any other mode of get-
ting rid of foul air is required. But for those who do not care to
go to the expense of purchasing one of the globes, we should
recommend the employment of an outlet-shaft, expanding at one
end into a cone, situated over the ceiling-flower, and opening at

the other extremity into the chimney. This we have seen in
some houses, and its effect has been admirable. A somewhat
similar contrivance is shown in the adjoining cut. Indeed, the
6e sun-light ” method of illumination is generally one of the
best modes of ventilation ; and gas-lamps, provided with the
above arrangement, approach them in usefulness. No system
of ventilation can be considered perfect in which the gas-lamp
is not made to carry away the air vitiated by its use.*

We come now to another consideration, which, if of not so
grave a nature, at all events demands every attention. We refer
to the mode of introduction of pure air. At present, in most

* We have not noticed Arnott’s chimney- valves and other similar con-
trivances, because we have no faith in their efficiency. They occasionally
interfere with the draught of the chimney, and in some instances allow
smoke to pass out, and thus injure ceilings, cornices, and such like.

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POPULAR SCIENCE REVIEW.

sitting-rooms the fresh air comes in at the windows and doors,
and when no other arrangement exists, we are sure to have
draughts more or less injurious, according to the size of the
interstices, apertures, &c. The question of where to introduce
the cold air has always been a vexed one with hygienists. Even
now, it cannot be looked on as definitively decided. Some
writers say, introduce it through the floor, as in the House of
Commons; others suggest a middle point between floor and
ceiling ; while the latest researches seem to show that the ceiling
itself is the best point. Whether the air be introduced at the
level of tne ceiling, or at a sufficient height above the door to
prevent unpleasant draught, is, in our opinion, immaterial.
The great points to be attended to are the distribution of the
air by causing it to pass through an immense number of aper-
tures, and the employment of adequate means to bring it to a
suitable degree of temperature. In most of the existing ar-
rangements for the introduction of fresh air into rooms, the
mistake is made of using a few small apertures (Sherringham’s
ventilators et id genus omne). Hence, we often find in the
houses of persons who pride themselves on the perfect ventila-
tion of their rooms, that these latter have abominable draughts,
whose course is defined with the greatest nicety, and which
often appear to select one’s ears as the most convenient
medium of transit.* This production of keen, sharp draughts
has been the opprobrium of nearly all the vaunted ventilators
hitherto employed. The method suggested by M. Morin, a
French savant, who has paid much attention to such questions
as these, obviates in a great measure these defects. His plan is
somewhat similar to that recommended
by the Commissioners for Improving the
Sanitary Condition of Barracks and Hos-
pitals, so that a description of the latter
will represent both. At the level of the
ceiling a number of perforated bricks
are introduced into the wall, the area of
the aperture being in the proportion of
1 square inch to every 60 cubic feet of
the capacity of the room.f In order to
prevent the discomfort which might arise from a down-draught
from these openings, a cornice is so arranged as to cover them.

PERFORATED ZINC CORNICE.

* Such draughts recall the sailor’s saying, that he u didn’t mind a fresh
sou-wester, hut he was blowed if he’d sit in the ‘wake’ of a key-hole.”
t A room 25 feet long by 18 feet wide and 10 feet high would have a
capacity of 4,500 cubic feet. Its apertures for entrance of fresh air would
therefore be 4,500-r-60=75 square inches. How large an area compared
with the apertures now occasionally found oyer our doors, and misnamed
ventilators !

VENTILATION AND VENTILATORS.

411

The upper side of this cornice is composed of perforated zinc,
which thus causes the air to be evenly distributed over the
room. The holes are generally from to inch in diameter,
and the area of the zinc perforated is to that of the air-spaces
as about 6 to 1.

Few systems are better adapted for the introduction of fresh
air than that of the Barrack Commission above referred to,
provided it is not required to heat the air before it is intro-
duced. When the air has to be heated, a new set of contrivances
is necessary. For ourselves, we think that, provided the cold
air is brought into a well-heated room at such a level as to
increase its temperature before it is breathed, and so distributed
as to prevent draught, there is little necessity for any special
device for warming it. In some cases, however, it appears to be
necessary ; and various appliances have been employed in rais-
ing it to its proper temperature. Of closed stoves for warming
the air, there have been legion ; but, we think, in all cases they
have proved objectionable, for they either burn the air which
passes through them, and thus render it most unwholesome, or
they impart to the heated air certain metallic impurities, which
are not only offensive, but hurtful. There may be exceptions
to this rule ; but, if so, we have not had the good fortune to
meet with them. Of hot-water and steam apparatus, for the
same purpose, we cannot speak in favourable terms ; they may,
doubtless, be economical, but they are unsatisfactory from the
two facts, that — 1. They produce an atmosphere which contains
impurities arising from the heated tubes, and which is extremely
distressing and unwholesome; and 2. That they are not un-
attended with danger, from the circumstance that rupture of one
of the pipes is likely to severely scald those in its proximity.
The open fireplace seems in all cases to be the best means of
warming, but it may be constructed so as to give out more heat
than the average grate does, and may be contrived to supply
warm air to a room. The following description of the open
grate recommended by the Barrack Commissioners will demon-
strate this. Though this grate is not absolutely new in prin-
ciple, it is not constructed on any one of the old plans, but
appears to be, as stated by Mr. Tomlinson, a combination of all
the good points in the older inventions : tc The grate is placed
as much forward in the room as possible. The part in which
the fire is contained is of firebrick ; the bottom being partly
solid, checks the consumption of fuel; a supply of air is
admitted from behind the grate, and is thrown on the top of
the fire to assist the prevention of the smoke. The sides are
splayed so as to throw the heat, by radiation, as much as possible
into the room. The opening into the chimney has no register.
There is a chamber behind the grate into which air is brought

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POPULAR SCIENCE REVIEW.

from the outer air, and warmed by the large heating surface of
the back of the grate, increased by flanges, and, after being

BARRACK COMMISSIONERS’ OPEN GRATE.

heated from 65° to 70° Fahr., the air passes into the room by a
shaft cut out of the wall, and which terminates in a louvred
opening placed ” near the ceiling. This is, we believe, one of
the best devices yet in operation, and it is the only one we
should venture to recommend. The plan of heating the air
of a house by placing a closed stove in the lowest chamber, and
causing the fresh supply to enter each room at some point above
the door, is thought satisfactory and efficient by those who have
tried it, and is said to work thoroughly well in Sir John Robin-
son’s house at Edinburgh, of which the adjoining woodcut
represents a section. The air is heated in the basement storey
by what is known as a “ cockle stove.” Thence it ascends
along the staircases, and enters the various apartments through
ventilators above and below the doors. The vitiated air passes
through apertures in the ceiling of each room, and into a shaft-
whose outer opening is above the roof of the house. We have
no personal knowledge of the efficiency of this plan of ventila-
tion, but it is alleged to be perfect.

It remains for us to say a word or two about the ventilation
of sitting-rooms in summer. In warm weather it frequently
happens that the ventilation of rooms is a matter of some diffi-
culty. In the daytime, the only natural mode of ventilation is

VENTILATION AND VENTILATORS.

413

through the open window, and unless this be supplemented by
an artificial contrivance, we know of no other better method. At
night, the employment of gas, with a central air-shaft, is likely to
produce a tolerably good in-draught by removing the foul air.
The chimney, too, is thought to assist in producing a current

outwards, but this does not always happen ; indeed, it not un-
frequently occurs that the draught through the chimney is into,
not out of, the room. A convenient mode of remedying this,
but one which is seldom used, is to keep a small gas-jet burning

414

POPULAR SCIENCE REVIEW.

in the grate. This is quite sufficient to produce a very power-
ful out-draught of air, while it adds nothing to the temperature
of the room ; its expense, too, is slight compared with the
benefit it confers, and there is little difficulty in arranging it, as
a flexible varnished tube may easily be carried to the burner
from a joint fixed in the neighbouring gas-pipe.

Had we not already transgressed the limits originally assigned
to our remarks, we should have entered on the subject of
mechanical systems of ventilation — such arrangements as the
steam-fan employed in the Eeform Club House, the furnace of
the House of Commons, the air-ffiters of the Post Office, the
steam-jet employed by Dr. Edmonds in ventilating the lower
decks of ships, the heated-tube system of Mr. Sutton for a
similar purpose, and various other contrivances, whose names
alone constitute a formidable list ; but we must draw our obser-
vations to a close. What we have said, has been said rather with
a view to draw the attention of the thoughtful to a subject of
the most vital interest, than to convey the idea that any per-
fectly satisfactory scheme of ventilation has yet been proposed.
Our aim has been to lay before our readers a general expression
of the conditions as to the quality of air necessary for healthy
ventilation. This, we think, has not hitherto entered suffi-
ciently into the considerations of those who have pursued the
study of methods instead of principles. It must, nevertheless,
be admitted that no system of ventilation can be satisfactory
unless it be in accordance with the laws of hygiene. Of these
laws, as they relate to ventilation, we have given our readers
a general idea ; and we would, in conclusion, assure them that
since they are capable of mathematical demonstration, they must
inevitably form the basis of every efficient plan for the main-
tenance of a healthy atmosphere in our private dwellings and
public buildings.*

* With one or two exceptions, the woodcuts illustrating- this article have
been borrowed from Weales’ excellent treatise on “ Warming and Ventila-
tion.” For the stereotypes we are indebted to the courtesy of Messrs. Virtue.

415

PHYSICS OF THE BRAIN.

By B. W. RICHARDSON, M.D., F.R.S.

I HAVE recently been carrying out some new researches on
the brain, with the view to discover its several seats and
places of function, and the Editor of this Review thinks that
I may be able to make the nature of the research so simple
that all who may read will follow. I do not see why I should
not ; for, after all the terrible obscurities thrown about it, the '
brain is an organ not very difficult to understand. It comes
sharply enough under the Grladstonian definition of flesh and
blood, and when we have the courage to approach it, and look
into it, it gives way to inspection with moderate facility.

Thomas Willis, M.D., and his Part.

I find in books of learning and knowledge no glimpse of
satisfactory thought, guess thought or real, respecting the brain,
up to the time of Thomas Willis. Willis lived in the reign of
Charles Mutton, sometimes called Charles the Second, and Willis
died in the same reign, his death accelerated, it is said, by a
cruel joke of the mutton-king. I have at this moment before
me a small portrait of this first physical philosopher of the
brain, the man who had the courage scientifically to open the
skull-casket and find out what was the nature of that rounded
structure which, like a world within a man, takes in all that is
outside the man and binds him bodily with the universe. The
face of Willis, as it looks up at me through the long gap of two
hundred years, is strikingly singular. It is a pensive face with
a meaning in it, determinate to a fault, and yet with a modesty
of expression that shows a sensitive soul behind : — the face ex-
actly of a man who under the smart of a king’s joke resounding
everywhere would feel acutely and break his heart in silence
rather than reveal the pang.

What nonsense was talked about the brain prior to the time
of Willis, I need not stop now to state ; except one fact which
illustrates many more. There was a notion that a common
cold was the phenomenon of the direct distillation of brain-stuff
through the nose, and it is wortlry of note that men of the

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Willis school had as much trouble in disposing of this mild
delusion as they had in setting forth positive discovery.

The discoveries of Willis were indeed very grand when mea-
sured by what they dispelled and by what they proved. That the
brain was an organ of actual flesh and blood ; that it was nourished
by blood, and was specially well supplied with blood ; that it
was covered with membranes and divided into distinct parts ;
that animals had brains built of the same matter as human, but
of less magnificent quantity; and that the quality of mind
had relation to the quality of brain with varying gradations
through the scale of living organic being — these, in the rough,
were certain of the gigantic truths taught by the dutiful and
right loyal subject of Charles Mutton.

Aeter Willis. G-all, and his Part.

After Willis, the brain became a fine field of study for anato-
mists of all schools ; but, with a few exceptions, anatomists have
never been more than industrious men, painstakers, with some
hard observance and little insight ; and so it happened that the
poor brain, cut up after the fashion of cutting up a Dutch cheese,
was subjected, long after it was discovered as an organ, to
infinite anatomical torture and fearfully insulting misnomer.
To this day, the names given to certain parts of the brain are
painfully absurd : it is made to have valves and writers’ pens,
fissures and roads, bridges and canals, beds, curtains and floors,
hard bodies which are really soft, and white bodies which are
not white, to say nothing of two approximate parts really not
mentionable, even in simile, in polite society. At length the phy-
sical metaphysical labours of Gall helped somewhat to render
the study of the brain less nominal and less obscure. Gall, by his
dissections, by his careful tracing out of the diverging fibres,
and by his happy and, in many respects, correct and simple
divisions of the organ into centres, placed observers on a train
of research which was full of promise. Unfortunately his dis-
ciples, not excluding the distinguished Spurtzheim, followed in
the metaphysical direction to which their master had led them,
rather than to the physical. This tendency was in every sense
natural. It was the continuous road of enquiry, much widened
and more soundly paved, while the physical highway was doubt-
ful from its newness, and especially from the labour- demanded
for traversing it. The metaphysical path was luxurious, open,
and tempting even to fascination ; the physical was hard, narrow,
and unpromising, nay threatening, to the beholder. Thus
sprang up the system of Phrenology, a system in advance of
facts, and therefore, though containing many truths, a system
based largely on belief, and fluctuating as belief itself.

PHFSICS OF THE BRAIN.

417

After Gall. Majendie and others, their Parts.

Meanwhile, to a large extent, the old anatomy of the brain
has remained but little changed ; still exist the absurd names,
meaningless, bewildering, and so adhered to, that within the
last five years two of the greatest lights in comparative anatomy
of this age have been holding desperate contest on one poor
nodule, the physiological value of which is altogether unknown,
and indeed little cared for, in respect of its function, throughout
the controversy. At the same time, it is right to explain that
the progress of rational physical discovery, into the nature and
function of the brain, has been advancing with some determinate
casting-off of the fnystical and hypothetical. The classification
of the brain into ganglia or centres of power, and into com-
missures or connecting bands, and the tracing of nerves into
the brain-structure, a study which the late Mr. Grainger so
admirably and industriously promoted, have all been aids of no
mean value to the direct and positive appreciation of function.
In the way of minute anatomy, also, a wonderful field of truth
has been laid open, especially by the labours of Swan and
Lockhart Clarke: while the chemists have been indefatigable in
determining the chemical constituents of the organ and their
relation to each other. Finally, the pathologists, in a quiet and
unassuming research, have added a long array of new facts on this
vast subject. Observing the phenomena of disease in instances
where the functions of the brain have been disturbed, they have
sought, after the death of the subject in whom the symptoms were
presented, to find the precise seat of the disease, and so to trace
the living phenomena to their true cause. In this direction our
accurate and philosophical countryman, Dr. Wilks, of Guy’s
Hospital, has taken a part which is beyond all commendation.
I must linger no longer on these matters, but must proceed to
note some purely physiological facts, for the illustration of
which this paper is specially intended. To Dr. Philip, Majendie
and Fluorens we owe the first real steps in advance for exploring,
by physical experiment and analysis, the functions of the brain.
It was unfortunate for these observers that their work was laid
out before they had the necessary means for conducting it with
satisfactory exactitude. Their experiments, often singularly
accurate, were, from the mode of their performance, open
to criticism. Knowing nothing of any methods for modify-
ing brain-function short of actual removal of portions of the
brain of the inferior animals, they proceeded by what is called
ablation, or cutting away, of the living structure. Hhe result
was that they took what they could not restore, and, as a conse-
quence, left it often doubtful whether the symptoms they

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POPULAR SCIENCE REVIEW.

elicited were those of mere shock, injury and pain, or of actual
dismemberment of function.

Dr. James Arnott. His Part.

The great leading discovery that the brain of a living animal
could be frozen and afterwards could recover was made by Dr.
James Arnott, who solidified the brain of a pigeon by exposing
it to a freezing mixture. Here research stopped, because with
an ordinary freezing mixture it was not possible to act on indi-
vidual parts of the organ : but the importance of the discovery
is not the less on that account. It was a marvellous revealing.
Think what it was ! Here was a living organ of mind, a centre
of power — of all guiding power, of all volition. It took in every
motion of the universe to which it was exposed. It took in
light and form and colour by the eye ; it took in sound by the
ear, sensation and substance by the touch, odour by the nos-
tril, and taste by the mouth : it gave out, in return or response,
animal motion, expression, all else that demonstrates a living
animal. With it the animal was an animal; without it the
animal was turned into a mere vegetable. And this organ, the
very centre and soul of the organism, was, by mere physical
experiment, for a time made dead — all its powers ice-bound.
And this organ, again set free, received its functions back again,
and, as we know now by further observation, its functions un-
impaired. Surely this was the discovery of a new world ! The
discoverer of such a world needs no praise, for to him comes
honour as a birthright, the noble birthright of an interpreter
of natural truths deep from the depths of nature in her most
sacred treasury.

Recent Research. Freezing the Whole Brain.

Recently, by the advancement in the means of application
of extreme cold, we have had laid before us a new line of
enquiry ; we have been enabled to destroy portions of the brain,
as well as the whole organ, temporarily, and we have been
also enabled to observe the process of recovery from this form of
brief death. Thus we have witnessed death of parts of the
brain, and their restoration from death, and by comparing
functions lost with functions regained, have traced out, with
singular correctness, many facts which by no other means
could have been so certainly revealed.

I was myself so favoured as to learn a simple mode of
producing an intense cold with volatile fluid in the form of
spray, and of so adapting this that even the brain could be

PHYSICS OF THE BRAIN.

419

temporarily destroyed in parts or sections. Then I and another
physiologist, Dr. Weir Mitchell, of Philadelphia, took up simul-
taneously and independently the study of brain function by
destruction of part. The truths thus learned, in so far as they
relate to my own work, I would now record. I put them for-
ward as being yet limited, but not valueless.

I shall begin the narrative best by stating that the brain
matter contains two substances which admit of solidification by
cold, viz., water and fatty matter. These solidify at different
temperatures, but both are entirely frozen by reducing the
temperature to 16° Fabr. or 16° below freezing point. At this
degree all the water of the nervous structure, amounting to 84
per cent, of the whole, is crystallized as ice ; in this condi-
tion the structure is for the time dead, it is as though it were
removed from the body altogether.

Suppose, then, that we bring into this state of temporary
death the front part of the brain, the two lobes or hemispheres
of the cerebrum or larger brain, which mainly fill the skull.
The phenomena produced are those indicating entire loss of
volition, of sensation, of all that may be considered intelligence.
To appearance the animal profoundly sleeps, it is as if it were
under the( influence of chloroform or ether, and an operation of
any kind may be performed upon it without pain. It may,
nevertheless, move when handled, and it may show a kind of
involuntary life due to what is called spinal action, to some power
resident in the spinal cord. A frog thus circumstanced will
sometimes leap ; but warm-blooded animals, as a general rule,
will remain like as in catalepsy, always retaining the position
in which they last were left.

In cold-blooded animals, as in the frog, when the functions
of the brain are entirely suspended, the freezing process may be
carried to and through the spinal cord, and every portion of the
nervous system may thus be deprived of force, the animal re-
maining motionless, rigid, and indeed like stone. In this state
it would remain, I believe, for an unlimited period of time if it
were kept under the same condition of temperature ; but from
this extreme condition of shrunk death it will, nevertheless, re-
cover on gradual restoration of warmth. In some warm-blooded
animals we see an approach to this same state, naturally brought
about in the period when they are hybernating, in the profound
sleep of the cold season ; but there is this difference, the
animal, during hybernation, still breathes, and still takes in some
air for respiration, without which it could not recover with the
return of warmth. And we find by experiment that if the pro-
cess of freezing artificially be carried on in a warm-blooded
animal, from the brain into the spinal system, so as to stop

VOL. VI. — NO. XXV. H H

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the function of respiration, the living action is put an end to
for good.

The statement of this fact will naturally suggest the ques-
tion, Why is there this difference between warm and cold-
blooded animals ; between a frog, for instance, and a pigeon ?
The answer to the question is simple ; the frog requires only,
for its best life, a comparatively low temperature, and its outer
covering or skin is a fair conductor of heat. Hence the frog,
after being entirely frozen, can take up sufficient caloric from a
warm air to become recharged directly with force throughout
all its nervous organism ; but the warm-blooded animal, living
always by the heat it developes in its own body, is protected by
a skin covered also with a good wow-conducting surface of
feathers, or fur, or hair: it cannot, therefore, so receive heat
from without as to be able to recharge its nervous centres from
any external source of heat ; it dies outright whenever its in-
ternal and radiating force is cut off.

To return to our animal made lethargic and insensible by the
direct abstraction of caloric from the cerebrum. I have said
that it resembles an animal sleeping after the inhalation of
chloroform, and this is indeed what is observed. A pigeon will
lie motionless and insensible for long periods of time, breathing
slowly, but regularly, and with the heart beating in even time.
By allowing the temperature to be gradually raised to 60° or
65° Fahr. there follows steady recovery and return of living
function ; but the order of recovery is not always the same,
variations being introduced dependent upon the parts in which re-
storation begins. Usually, however, when the whole mass of the
cerebrum, or larger brain, is frozen, recovery of intelligence is
the first sign exhibited ; then there are attempts at motion, which
are propulsive forwards, and soon afterwards there is sensation.
I have, however, seen this order, reversed, the sensation returning-
before the return of motion. Finally, the animal entirely re-
covers, and with the recovery memory and all the spell-bound
faculties return into active play. The brain has been crystallised,
and it has been loosened back to the fluid state, but it has lost
as little as it has gained ; all impressions it held it has retained,
and the light, and the sound, and the touch, and the odour, strike
again to reach and endow the now impressionable matter.

Freezing Sections of Brain.

So far we have seen the effect of removing force from the
cerebral part of the brain substance as a whole ; let us next
enquire what is the effect of removing force from special parts
of the organ. As preliminary to this description I should
explain, that the brain substance being a bad conductor of

PHYSICS OF THE BRAIN.

421

caloric it is quite possible, by using a fine ether jet and a low
boiling fluid, to isolate parts with great minuteness. Thus we
can remove the force from the two large front cerebral hemi-
spheres without removing it from the smaller hemispheres which
lie behind, and which form the little brain or cerebellum ; it is
possible again to remove the force from one hemisphere with-
out removing it from the oth£r, or from the spinal cord without
interfering either with the large or the small brain.

In the superior and front part of each hemisphere of the
cerebrum there lies a mass of nerve matter very distinct in
form, and, as it would seem, very distinct in function. The
older anatomists called this the striated body ( corpus striatum ),
because in section it appears to be marked by faint lines of
grey and white colour. It is now more correctly called the
superior cerebral ganglion. With very little difficulty, and
without pain, we can expose this ganglion in one or both
hemispheres, and remove the force from one or from both.
When we have removed the force from both — when, that is to
say, we have solidified them, and, for the time, destroyed their
function — there is presented this singular phenomenon: the
animal falls forward, or sometimes rushes forward with unmean-
ing impetuosity, and these symptoms will last until the relaxa-
tion and restoration of the ganglia is complete.

We change the line of experiment; we turn from these front
cerebral ganglia to the lower large ganglia which lie at the
back of the skull, and form the smaller brain or cerebellum.
We lock up these, by taking from them their force by cold, and
at once the animal marches backwards, and turns backward sum-
mersaults, and in the most determinate manner shows that it has
no control over these movements until its cerebellum is set at
liberty by the restoration of caloric.

If the anterior cerebral ganglia, together with the cerebellum,
be simultaneously deprived of force, there is neither backward
nor forward movement, but prostration of movement for the
time, with equal restoration of power consequent on equal
restoration of force.

Throughout all these induced changes on the great centres of
nervous power, it is observed that however much the volition,
the perception, and the sensibility of the animal are reduced, the
semi-voluntary and involuntary acts, the acts of respiration and
the motions of the heart, are not prevented. To say they are
not affected is not strictly true, for they are rendered slower
after a time and feebler ; but this is an indirect retardation of
function, and would occur if any other large surface of the body
were for a long period deprived of caloric ; but we may say, con-
fidently, that the removal of force from the large and small
brain does not seriously interfere with the functions named.

H H 2

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POPULAR SCIENCE REVIEW.

When, however, we pass beyond the great and little brain and
approach that part of the spinal column which is in immediate
connection with them, we are introduced to new phenomena.
The part immediately leading from the brain is called the
medulla oblongata, and as we subject that part to the influence
of the extreme cold we instantly interfere with, and even stop,
respiration, so that the animal, if it be a warm-blooded animal,
will die, as suddenly as dies the Spanish bull from the short
sword-thrust of the skilled Torero ; but the heart still continues
in action, and, if the breathing be sustained by artificial means,
the heart will remain in action even though the influence of
the cold be made to extend to the wThole of the spinal cord.

When only the upper surface of the cerebrum or large brain is
superficially frozen, the power to move remains, although the
perception and sensation are entirely destroyed. Indeed, in
this condition there is often active movement of the body, but
altogether without will or desire. The motion in this case is
not motion of one particular and exaggerated type, but general,
uncontrollable motion, such as is seen in some forms of insanity
in man.

I might extend these observations respecting the removal of
force from the brain, but I see I am already trespassing on
the pages of the Review, and I feel that I have given enough of
experimental fact to illustrate as much as I can this time put
down upon paper.

Deductions. — The Force and the Matter.

On reviewing the facts disclosed in the experiments that have
been described, we learn that the force by which all the mani-
festations of brain function are sustained is the force we call
caloric, or commonly, and by -incorrect speech, heat. Two
evidences lead to this truth : the first, that all the manifesta-
tions are withheld when caloric is withdrawn ; and the second,
that all the manifestations return when the caloric is restored.
But inasmuch as with the restoration of action, there is continu-
ance of the impressions which were made on the brain before
any force was drawn out of it, it follows that the extant force in
the brain at any given moment, is not the seat of the impres-
sion, nor the cause of it, but the means by which the matter of
the brain is held ready for the reception of the impression, and
for the production of those manifestations which we denominate
functions. We are bound, therefore, to infer that impressions
are physical realities, stamped as it were on brain matter, each
distinct and perfect when the matter on which it is set is in
condition for motion. Everything we remember is, I doubt
not, thus imprinted on the brain, on infinite points of brain

PHYSICS OF THE BRAIN.

423

substance, each independent, free, and capable of motion when
the whole mass is charged with force. The brain, in fact, is a
world within of the world without, a camera of all from the
wTorld without that it has received in the course of its waking
life. Until recently the idea of such a physical microcosm could
not have been conceived ; now it comes forward strengthened by
physical truths of human invention so called. I hold a piece of
transparent glass in my hand and see nothing upon it. Nay,
says my friend the micro-photographer, look again. Still no-
thing there? No! Then he slides the glass under his lenses
and adjusts, and repeats, “ Look again.” I obey, and lo ! before
me on an infinitesimal space of matter is the Pater Noster, as
legible as it used to be in an old church I well remember,
where it covered half a wall, and, with the ten commandments
to balance it, enframed the Lion and the Unicorn, and Greorgius
Eex, and the Grarter, like a holy family.

When we see v7hat the micro-photographer can thus do in
putting physical impressions on what seem infinitesimal points of
matter, and when we know that there is no assignable limit to his
art, it is no crude inference that in the vast surface of the grey
matter of the brain, in those cerebral lobes of which I have
spoken, myriads of points of matter are thus impressed — points
of matter floating in that eighty-four per cent, of water of
which the brain is made up. I call up to remembrance a ridge
of hills which were often before me in childhood. I see them
in all the distinctness of that time, their height, their breadth,
their length, their divisions, the structures upon them, all their
belongings. Why do I see them ? Because they are actualities
still in my brain, imprints on points of matter there. But
twenty yehrs elapse, and I look on those hills again, and they
are and yet are not what they were. They seem to my present
view smaller, that is certain ; and one of them was barren,
and now it is cultivated; and one had a mill on its sum-
mit, and the mill is gone ; and one had two or three trees on its
side, which in the distance looked like the flint and steel of an
old-fashioned gun, but now in place of those trees is a copse.
These are not the hills, in fact, which I have carried so many
years, for now as I take them in once more my capacity for
taking has changed and the hills have changed. I must have
therefore a new picture altogether ; and from this time forward
I must carry two pictures of those hills, the child’s picture and
the man’s picture ; for the old is not put out by the new, nor
the new by the old.

Physical points of brain for physical impressions are then
essential ; but to reveal their impressions they must have force
and condition for motion. Let us remove that force, abstract
it, as it comes to the part, by cold, or crush it out b}7 firm
mechanical pressure, or cut it off at its source by putting out

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the animal fire, and then the impressed molecules, losing condi-
tion for activity, and coming to rest, cease, functionally to exist.

But they do not cease actually to exist ; because, whether
they be bound in ice or bound by pressure, we see that when they
are unloosed they can return, if the body can supply them with
caloric, to ’full vigour. Indeed, the images of the brain, once
well developed and fixed, can only be obscured by derangement
of brain matter, and can only be destroyed by disintegration of
brain matter. Cases have occurred in which, under pressure of
brain, a man has been for months dead to the outer world, and,
on recovery has remembered what preceded his accident, show-
ing thus that the imagery of his brain remained intact ; and, as
I have said already, an animal with a frozen brain, when it is
restored, will not show an evidence of a lost faculty. By dis-
integration of brain matter the world within of the world with-
out only dissolves. This disintegration is, in all men and ani-
mals, going on slowly, and thus memory becomes defective. In
second childishness this gradual metamorphosis, this natural mode
of removing the world and its past from the man, is completed ;
it is the dissolving view of nature. In the vigorous the imagery
of the brain is finally destroyed by death alone, and by death
not of necessity immediately, but with the after disintegration
of structure. A brain frozen in a living animal, and with the
animal crystallised in ice, would retain, in that condition, the
imagery with which it was replete for any grasp of time ; for
time is no element when there is no change, nor is it recog-
nisable by aught except change of matter by force. When I
wind up my watch I put into it so much force, which force is
expended in moving so much matter, and the measure of that
movement is the measure of motion, — time.

The force called caloric, then — the force we liberate in the
combustion of blood — is the sustaining force of the brain, but
it is not the only form of force to which the brain is im-
pressionable when its natural condition is maintained. Through
the eye calorific force does not pass to the brain but is cut off,
yet the form of force called light, and probably the actinic force,
make way ; while through the ear and tactile skin common
mechanical force finds ingress. We see, we hear, we feel, in
fine, by the direct action of forces other than caloric, but
without caloric as the base these are unavailing, for an animal
with a frozen brain cannot be awakened neither by light, nor by
noise, nor by touch ; if it could a dead animal could be awakened
by the same means.

Sleep and Dreams.

The course of our research leads us, as we have seen, to con-
template the condition of the brain in its active state, and under

PHYSICS OF THE BRAIN.

42*

artificial states in which its functions have been suppressed.
But we are led also to another subject, I mean the natural iner-
tia or rest of the brain, which we call sleep. Physically the
brain asleep is the brain exhausted of its force — force expended
during waking hours in the production of its equivalent of
animal motion. As the sleep creeps on, the natural imagery
of brain rests. During sleep, motion being suspended, the
brain and nervous centres altogether are recharged, and natural
awaking is the index of the fact.

But it is not always that the brain centres rest as a whole, or
work as a whole. Sometimes one part of the brain works while
the rest sleeps, and then we dream in sleep, sleep being the major
phenomenon. Carmichael, many years ago, well taught that
there are seven distinct stages of waking and sleeping. 1. When
the entire brain and nervous system are buried in sleep , then
there is total exemption from dreaming. 2. When some of the
mental organs are awake , and all the senses are asleep , then
dreams occur and seem to be realities. 3. When the above con-
dition exists , and the centres of voluntary motion are also
awake , then may occur the rare phenomenon of somnambulism.
4. When one of the senses is awake with some of the mental
organs , then, during our dream, we may be conscious of its illu-
sory nature. 5. When some of the mental organs are asleep ,
and two or more senses awake , then we can attend to external
impressions, and notice the gradual departure of our slumbers.
6. When we are totally awake and in full possession of our
faculties and powers. 7. When , under these circumstances , we
are so occupied ivith mental operations as not to attend to the
impressions of external objects, then our reverie deludes us like
a dream. These are faithful observations, and define with ex-
actitude the fluctuations of force in the brain under different
conditions. In experimental research, and in disease, we have
the same phenomena brought before us, and they all accord as
to cause.

Intoxication.

There are various modes of producing insensibility artificially.
The insensibility of intoxication from alcohol is an illus-
tration at hand. The insensibility thus produced is the same
as that from cold ; the agent taken, that is to say, interferes
with the distribution of force through the brain substance, and
is carried away at the expenditure of so much force as shall be
required for its elimination. At the late meeting of the British
Association for the Advancement of Science at Dundee, I showed
that the period of action of alcohols of different kinds could
be determined by the force required to lift them out of the
organism. Moreover, various of these intoxicating substances,

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POPULAR SCIENCE REVIEW.

which all act in the same manner as cold, pressure, or exhaus-
tion, affect differently sections of the brain matter, producing
various phenomena analogous to dreams.

Lastly, some other external influences, by causing concentration
of force on one particular part of brain, may so reduce other parts
to rest as to cause that inertia which Carmichael calls reverie.
This is a disturbance of the equilibrium of force in the brain
which can be intensified by practice; and there is no difficulty in
tracing the phenomena of mesmerism, such as they are, to their
physical source when the nature of reverie, or waking dream, is
explained and understood.

Balance of Power in the Brain.

One more fact relating to the physics of the brain, as taught
by experiment, and I have done. We have seen that when
the anterior cerebral ganglia are destroyed for a time, an animal
moves impulsively forward, and that, when the cerebellum is
destroyed, the animal moves impulsively backwards. This in-
dicates the existence of a balance of power between these centres
— a balance which is also detectable between other centres. It is
therefore a fair inference, that every centre of power in the
brain is, during healthy states, physically balanced, and that
what is called a well-balanced mind is really a properly ba-
lanced brain. By this reading we explain many phenomena of
living action otherwise inexplicable.

By constant overaction one centre of the brain may gain
undue power, which shall be so persistent as to distinguish the
man throughout life. Or a centre of power may be suddenly
prostrated, and the balancing centre, no longer controlled, may
overcome all for the moment, and produce phenomena not
before observed in the same organism. Impulses — sudden,

vehement, propulsive, onward, under the influence of any im-
pression which for a moment paralyses the cerebrum, are thus ex-
plained. Whenever the cerebrum alone is overcome with sudden
shock, it fails in power the same as when its structure is de-
prived of force by the direct action of cold or by pressure:
then the propulsive cerebellum unaffected shows its force un-
checked, and there is forward rush. In some stages of disease of
the cerebrum and specially of disease induced by alcohol, there is
this break of balance. I lately pulled out from under a railway
train the headless trunk of a man. Passing into a tunnel out of
which the train had emerged, I found the brain of this man entire,
and while the servants of the company were fetching the police,
I read in the brain his physical history, and interpreted it to the
Inspector by my side. I discovered that while the cerebellum was
quite sound the anterior lobes of the cerebrum were intensely con-

PHYSICS OF THE BRAIN.

427

gested with blood, and had undergone previous disease. I found
the anterior cerebral ganglia specially involved, and from the
whole of this dumb but forcible evidence, I learned that the man
was insane, that he had been insane before this time, that his
insanity had taken the impulsive character, and that in a fit of
extreme and uncontrollable impulse, he had committed suicide
by throwing himself under the train. When the facts of this
man’s life were brought out before the coroner, Dr. Lankester,
they gave the same evidence to the letter, nor less nor more.

In the heat of battle it is not the cerebrum but the cerebellum
which propels the man on ; in the chase in the race it is the
same. The vehement tendency to rush forward, which nearly
all persons feel when they look over a deep precipice, is of the
same nature. The cerebral ganglia, overcome by the impression
made upon them, are, for the moment, deprived of power, and
the cerebellum, acting with sudden and uncontrolled force, gives
the initiative propulsive start towards what is sometimes a
deadly fall. But I must cease. If in the physics of the brain
I have shown that some things, deeply interesting in their social
as well as their physiological meanings, are known, what have I
not unintentionally shadowed forth of that which has yet to be
discovered, by the bold, the diligent, the truthful disciple of
nature ? Who shall show how the imagery of the brain is phy-
sically cast; who shall disclose that imagery as a world to be
visibly seen ? Yet in the days to come even these things,
simple as known as wonderful when unknown, shall be revealed.

428

REVIEWS.

THE, SCIENCE OE SOUND.*

HPHOSE w]io witnessed the admirable series of experiments given by
-A. Professor Tyndall, in bis late course of lectures on Sound, will be glad
to learn that the facts and theories then brought under their notice have
been reproduced in a work whose method, as a scientific handbook, is only
excelled by the grace and terseness of its literary style, and the clearness and
abundance of its illustrations. Very few of us have paid attention to the
science of acoustics, and the reason of this is, we apprehend, the circum-
stance that our teachers, through ignorance or design, have universally
passed the subject over as one of little interest, and of still less scientific im-
portance. Even a cursory glance at Dr. Tyndall’s book will convince the
student that a splendid field of research and experiment has been left un-
noticed by writers on Natural Philosophy. The phenomena of Sound offer
for solution some of the most complex problems which the whole range of
physics present ; and the laws which regulate them, display an order and
correlation unsurpassed in any department of Natural Science. The author
of the present work does not pretend to offer many original views upon the
fact3 of Sound-Science, his object having been rather to bring together all
that is known concerning the laws which regulate vibration, and to discuss
the curious facts connected therewith, which have been recorded by various
continental writers. This he has done most thoroughly, and, in addition, he
has brought his own powers, as our greatest and most successful experimenter,
to illustrate theories which without this aid would have been difficult of
comprehension to ordinary readers. As performed in the leetures, some of
the author’s experiments had the rare quality of bringing conviction home
to the minds of his pupils : as gone through on paper, in the book before us,
they have lost little of their original force. The woodcuts intercalated in
the text are so numerous and well executed, and the explanations are so
lucid and forcible, that no well-educated man can fail to make himself
acquainted with acoustics, if he has a real desire to learn. The book is
divided into eight chapters, in accordance with the number of lectures
originally delivered, and each chapter is followed by a summary, which will
be found useful by the student, whom it enables, in a brief space of time, to
travel over ground whose features might be otherwise forgotten. We have

* “Sound.” A Series of Eight Lectures, delivered at the Poyal Institu-
tion of Great Britain. By John Tyndall, LL.D., E.R.S. London : Longmans.
1867.

REVIEWS.

429

not space for an analysis of the contents, but we may offer a few of tbe head-
ings of tbe chapters, as indicative of tbe wide range of subj ects discussed : —
Nature of sound, its propagation ; Newton’s and Laplace’s formulae ; influence
of beat, density, and elasticity ; vibration of sound in various bodies ; distinc-
tion between music and noise ; periodic and unperiodic impulses ; vibration
of tuning-fork 5 tbe syren ; wave-lengtbs of tbe human voice ; vibration of
strings j sound-boards j nodes and ventral segments j timbre ; overtones j
clang-tint ; special harmonics and their abolition ; vibrations of rods ;
kaleidopbone ; musical box ; harmonica ; disks and bells ; longitudinal
vibration of wires ; vibration of pipes, stopped and open ; resonance reeds ; tbe
organs of voice ; sounding and sensitive flames, &c. ; vibratory motions in
water and air ; destruction of sound by sound ; theory of beats ; optical
illustration ; resultant tones ; combination of musical sounds ; theories of
consonance and dissonance ; interference of primary tones and overtones ;
musical chords ; mechanism of hearing, etc. Those above all who are in-
terested in music, and desire to appreciate the cause of the singular effects
so well known to musicians, should read Dr. Tyndall’s volume, in which
they will find a veritable mine of wonderful facts. The description of the
Syren alone is a dissertation on the theory of music. For clearness of
diction, and simplicity of explanation, this book stands unmatched. It is
the best popular treatise on sound ever published, and it is withal the most
comprehensive and accurate student’s handbook on the science of acoustics.

ASTRONOMICAL HETERODOXY.*

OUR readers, of course, accept the ordinary doctrine of astronomers, that
the earth moves round the sun : indeed, we are disposed to think that
many would resent any attempt to turn their faith on this point as a piece
of insanity. There are few of us so calm as the metaphysician who
alleged that if a man bearing a reputation for common sense came to him and
said that two and two make five, and not four, he would listen to him and hear
his arguments. But, after all, the acceptance of a faith, no matter how general
or implicit it be, is no criterion of its soundness. It must be remembered
that when it was first asserted that the earth moves round the sun, and not the
sun round the earth, the assertion was not only listened to with doubt, but
was rejected with derision. Besides, it must be confessed that the demon-
stration of the absolute movement of the earth round the sun is by no means
the easiest matter in astronomy. To prove a relative movement is no dif-
ficult task ; but to decide which of the two, the sun or the earth, is the
fixed and which the moving body, is a problem which is certainly none of
the simplest. The author of the brochure before us, tries to show not
only that this is difficult; but that it is impossible. He does not deny
for a moment the fact of a relative movement of the sun and earth ; but he
contends that there is no mathematical evidence to prove that it is the earth,
and not the sun, which performs the orbital circuit. The arguments he
adduces to show the fallacy of our present proofs are both numerous and

* 11 The Theories of Ptolemy and Copernicus.” By A Wrangler. London:
Longmans. 1867.

430

POPULAR SCIENCE REVIEW.

powerful ; but at tbe same time, while they show that the author has given
serious attention to the question, they give us the idea rather of the “ special
pleader ” than of one in search of truth. We, however, have no right to
enquire into motives. The chief evidence in support of the current doctrine,
is that which relates to Newton’s law of the gravitation of masses, to aber-
ration, and to parallax. The value of each of these is discussed by A
Wrangler, and, in his opinion, “ found wanting.” The law of gravitation he
objects to on the ground that it is in great measure an hypothesis, since we
cannot tell what may be the peculiar constitution of the heavenly bodies, and
cannot therefore infer how gravity may act in each particular case : for it
must be stated that A Wrangler has a pet hypothesis of his own, to the
effect that the specific force of gravity may be different for different sub-
stances. Aberration is, in his opinion, useless, because he thinks that it may
be explained upon either supposition — that the earth moves round the sun,
or the sun round the earth. Parallax is, he considers, equally unreliable,
because it depends for correction on aberration ; and thus he annihilates all
the testimony in which our poor credulous philosophers have been relying
for so long a period. What, then, the reader will inquire, is the ultimate
conclusion of this Iconoclast P We answer, none : he is merely an intel-
ligent sceptic, who says you believe too much, for there are no logical
grounds for your belief. We cannot afford the space to meet A Wrangler
seriatim on all the points which he has raised ; but even admitting the
possibility of both parallax and aberration being explicable on either
hypothesis, we can fall back on Newton’s grand law, which A Wrangler
has done nothing whatever to disprove, and we can say that it at once
removes all of those doubts which the peculiarities of parallax and aberration
tend, we confess, to engender. The way in which Sir John Herschel lays
down the evidence on this grave question is characteristically lucid, and we
cannot do better than refer our readers to the first chapter of his u Outlines,”
for a simple and convincing expression of the evidence in support of the
Copernican doctrine. In concluding his 77th paragraph, where he refers to
the deficiencies of the testimony, he observes : “ The Newtonian theory of
gravitation supplies this deficiency, and by showing that all the motions
required by the Copernican conception must , and that no others can, result
from a single intelligible and very simple dynamical law, has given a degree
of certainty to this conception as a matter of fact, which attaches to no
other creation of the human mind.” A Wrangler has failed to shake our
belief in Newton’s law, since he has done nothing to show that the principle
of gravitation is not universal ; and so long as we accept this law, so long
must we give our faith, so far, to the system of Copernicus.

MUSHROOMS AND TOADSTOOLS.*

"1/FU SIIROOM-EATING humanity owes a never-ending debt of gratitude
to Mr. W. G. Smith for the admirable work which he has just given

* il Mushrooms and Toadstools : how to Distinguish easily the Difference
between Edible and Poisonous Fungi.” With two large sheets, containing
coloured figures of 29 edible and 31 poisonous species. By Worthington G.
Smith. London: Ilardwicke. 1897.

REVIEWS.

431

it. Henceforth, assuredly, accidental poisoning by fungi should be made
penal, for with the assistance of the beautiful plates and the excellent little
volume before us, no such cases need occur. The author has spent a consider-
able portion of his life in the study of our larger fungi • and his attention has
not been confined to their botanical properties, but has been freely — indeed,
in some instances, too freely — given to the consideration of their dietetic
qualities. By this means he has acquired a fund of information, and a com-
bination of different varieties of facts, such as no other English fungologist can
be asserted to possess. This union of the structural and toxicological methods
of investigating the larger fungi is just what was wanted by those who desired
to extend the list of edible mushrooms beyond the one or two species now
eaten. No better instructor, therefore, than Mr. Smith could be found, and
with him as our guide we may fearlessly and agreeably indulge in fungi-
dishes, which to the less initiated might appear not only unwholesome but
even dangerous. The botanical or the gastronomic test, taken separately, is
almost useless ; but in combination they are unassailable and trustworthy.
We should be loath to eat a mushroom with which we were unacquainted
solely because the botanist assured us, a priori, that its structure guaranteed
its wholesomeness. In like manner, we should doubt even the man who,
though ignorant of its structure, asserted from his general experience the
good qualities of a fungus, for we should very naturally say to ourselves,
this fungus may resemble those which he has frequently eaten, yet may be
poisonous, for he knows nothing of its structure, and mere outward resem-
blances are deceptive. But in the case of our author it is different. Every
fungus which he states to be wholesome food he himself has eaten over and
again ; and of the action of the poisonous species he speaks with an equal,
though more painful, certainty, for on more than one occasion he narrowly
escaped death through his gastronomic experiments. Of the plates which
accompany Mr. Smith’s book it would be difficult to speak too highty.
They constitute two large sheets, about 36 by 18 inches each, one being
devoted to the poisonous and the other to the edible species. On these all
the fungi are figured, of life-size and in the natural colour. We perceive,
too, that the position of each has been so arranged that the mode of con-
struction of the gills — a very important point in diagnosis— is distinctly
shown. Whether we look upon these illustrations as the creations of the
highest artistic skill, or as the expression of the most thorough botanical
knowledge, we are compelled to confess that they are typical of excellence :
they cannot be surpassed in beauty or fidelity. For the purpose of field
work they are made (in a special edition) to fold and unfold like a map, so
that they may be carried in the pocket, and employed, sur place , in the
process of identification. The author’s introductory observations suggest
many important points to the amateur fungologist ; and though they can
hardly be styled scientific, they contain no inaccuracies. So far as the writer
goes his statements are correct, and his remarks on fungus cookery we dare
not pretend to criticise. We have derived both pleasure and profit from the
perusal of this work, and as we desire to see it as perfect as possible, we
would offer a few suggestions to the author, which we trust he may adopt
in the first of the many editions his work is likely to pass through. There
are two points in which we think Mr. Smith might add to the value and im-

432

POPULAR SCIENCE REVIEW.

portance of his hook : (1) by giving ail analytical key — like Mr. Bentham’s
scheme for the identification of phanerogams — with the assistance of which
the student could with safety refer a specimen to its species ; and (2) by
stating in every case the exact period of the year at which each species
may be found. According to the existing arrangement, the mushroom-
hunter, having found a specimen which he desires to investigate, is
either obliged to read the description of various species till he hits upon
the proper one, or else has to search through both plates till he has
found some illustration which corresponds to the specimen in question.
This is all well enough for those who are incapable of grasping minute
details of structure, and who therefore deserve to submit to the penalty of
delay ; but some more perfect provision should be made for the better class
of student. With reference to the second point, the deficiency can easily be
met, and we think it is important that it should be provided against. We
notice various species whose habits and character have been clearly stated
by the author, but whose seasons of growth have not been mentioned.
Of these the following are a few : — the variable mushroom, the furrowed
clavaria, the chantarelle, the fir-cone mushroom, the orange-milk mushroom,
the purple cobweb mushroom, the curled helvella, &c., which are edible.
The same may be said of the poisonous mushrooms. We dwell upon this
point of season because it not only is of interest to those who may wish to
seek a particular specimen, but because it appears to us the knowledge of
the period at which a particular species of fungus appears may be of value
to the student when he finds a difficulty in referring a specimen to its proper
place, &c. The collateral information which Mr. Smith lays before his
readers is curious, and will not a little astonish some Londoners. Those
who derive their supply of mushrooms from Covent Garden Market, and
who fancy that they obtain the common mushroom, Agaricus campestris ,
will be surprised to learn that the species supplied to them is what is known
as the horse-mushroom, A. arvensis. The latter not unfrequently is found
growing with the former, and is often mistaken for it ; nevertheless, it is
usually larger, coarser, and possesses a less delicious flavour. The top, in
perfect specimens, is smooth and snowy white ; the gills are not the pure
pink of the meadow-mushroom, but are of a dirty brownish white, which
changes to black ; its stem is disposed to be hollow, and is surrounded by a
large ragged u floccose ” ring. Now, this species is almost the only one to
be seen in Covent Garden Market. 11 Indeed,” says Mr. Smith, u after
knowing the market for many years, I have rarely seen any other species
there ; when the true mushroom, however, is there, it is frequently mingled
with horse-mushrooms, which seems to show that the dealers do not know
one from the other. In the wet days of autumn, children, idlers, and others
go a few miles from town into the meadows to gather whatever they can find
in the mushroom line. They then bring their daily stock to market, where
it is sold to fashionable purchasers, stale, vapid, and without taste — unless
it be a bad one.” Our author’s general remarks on each of the species are as
interesting as those we have quoted, and they have afforded us a good deal of
agreeable reading. The fungus season is now almost at its height, and we
advise all who are interested — gourmets and fungologists — to make Mr. Smith’s
book their field companion. We can say nothing more favourable of his
plates than that they are likely to be productive of very delicious dishes.

KEYIEWS.

433

A POPULAR FERN BOOK *

WE have been so inundated during the last few years with, books on Ferns,
that we felt at first disposed to be angry with Mr. Cooke for providing us
with another treatise. The work, however, is so good a one, and its price
is so low, that we welcome it as a means of spreading a taste for a branch of
botany, which, though much cultivated, is by no means exhausted. There
is, too, a completeness about this little volume which gives it a superiority
over some others of its class. No question connected with ferns is left un-
answered in its pages, unless it be the question of distribution, which, in our
opinion, has hardly received as much attention as the author might have
given it. But, perhaps, in a popular treatise, this point is not of much import-
ance. After all, the chief requirements of the botanist are, a knowledge of the
natural history of the class he is about to study, and a clear and accurate
account of those structural characters by which the several species may be
identified. In these respects there is nothing wanting in Mr. Cooke's little
volume. The titles of the introductory chapters give a good idea of the
subject-matter of the book. They are as follows General properties and
uses of ferns ; Structure ; How to grow ferns ; Pests and parasites (a point
on which the author is one of our highest authorities) ; How to form an
herbarium • classification. Then comes the description of the various species,
the common name being given above, and the scientific description being-
placed in a foot-note. The author’s classification is a convenient one, and, so
far as we can perceive, there need be no difficulty in its employment. He
divides all ferns into two primary groups ; those in which the spore cases are
deprived of a ring — Exannulate, and those in which a ring is present —
Annulate. The former include the Osmunda, Moonwort, and Adder’s-
tongue;. the latter contains two subdivisions, those in which the ring is oblique
embracing the filmy ferns and the Trichomanes, and those in which it is cir-
cular including all the other species. The other groups are based on the
character of the spore tufts and their covers. This classification is not merely
convenient, it is eminently a natural one, since it brings together the
Hymenophyllum and Killarney ferns, which all who are familiar with them
must admit to be very near relations. The particular to which we object in
this work is that to which we have already called attention, viz. that of
distribution. More stations might, we think, have been given. This is
especially true in regard to the distribution in Ireland, the Maiden-hair
being the only rare fern whose 11 stations ” in the sister island are fully given.
The statement which Mr. Cooke quotes, from the u Proceedings of the Dublin
Natural History Society,” is perfectly correct. We have ourselves seen the
Maidenhair covering the sea-cliffs of Clare and the islands of Arran, and
growing as luxuriantly as the royal fern at Killarney. Both the filmy ferns
may be found in great abundance in Killarney, especially in the neighbourhood
of O’Sullivan’s Cascade, where they grow to a size which prevents even an
ordinary passer-by mistaking them for mosses. In addition to the distinction
between the two species, H. Wilsrni and H. Tunbridgense , given by the

* “ A Fern Book for Everybody.” By M. C. Cooke. London : Frederick
Wame & Co. 1867.

434

POPULAR SCIENCE REVIEW.

author, may "be mentioned the fact, pointed out first by Professor Gulliver,
that in one species the cells are considerably larger than the other, a point
which even a good Coddington lens enables one readily to discover. The
statement that the Sea-spleenwort is only to be found on the south-west
coast (England), must be accepted with some qualification. We have found
it in great abundance in various parts of the south-east of Ireland. The
illustrations to Mr. Cooke’s book are divided between the plates and the
text, and are carefully executed.

BRITISH CONCHQLOGY.*

IN this the fourth volume of his British Conchology, Mr. Jeffreys continues
his description of the Marine Gastropoda, commencing it with the genus
Rissoa, and bringing it down to the genus Bulla. Of the general plan of the
work we have spoken in our notice of the earlier volumes ; we need only say,
therefore, that in the present instance the general scheme has been carried
out fully and faithfully. The genera described are in all cases as comprehen-
sively treated as the most earnest conchologist can desire, and the accessory
details are such as are not always to be found in systematic works on the
mollusca, unless indeed in the splendid treatise of Forbes and Hanley. The
plates in the volume now issued are nine in number ; the first one, which
forms a frontispiece, being an exquisite, coloured representation of the
singular Ianthina, and the remaining eight being carefully-drawn sketches W
Sowerby, of the genera referred to in the text. The table of geographical
distinctions shows the different areas of the recent and fossil gastropods, and
is valuable for purposes of reference. As a specimen of how the author deals
with a genus, we should wish our readers to take up his description of
Ianthina ; this, which relates to all points in the natural history of this singu-
lar creature, extends over nearly fifteen pages, and is a miniature monograph
literally crammed with facts; so well has the author condensed his observa-
tions. The fifth volume will complete the work, and will contain an account
of the remaining Pleurobranches, the Nudibranches (by Mr. Alder), the
marine Pulmonobranches, the Pteropods, and the Cephalopods. It will also
include a supplement and a series of plates, plain and coloured, depicting
all the species and remarkable varieties of British shells. When completed,
the work will be the most complete and compact treatise in our language.

GOLDING BIRD’S NATURAL PHILOSOPHY, f

THE old friend of our student days, our companion in the lecture-room and
the physical laboratory, is about to undergo a change of name, in fact, has

* “ British Conchology ; or," an Account of the Mullusca which now in-
habit the British Isles and the surrounding Seas.” Vol. IV. Marine Shells.
By J. Gwyn Jeffreys, F.R.S., F.G.S. London: Van Voorst. 1867.

t “The Elements of Natural Philosophy; or an Introduction to the Study
of the Physical Sciences.” By Charles Brooke, M. A,. F.R.S. Based on the

REVIEWS.

435

undergone it. The u Golding Bird,” as we used to term it at College, is no
longer to he Golding Bird, hut Brooke. The change is hut a just one. The
science of Bird’s time has passed, like Bird himself, from among us, and
the writer who has successfully carried the work through so many editions,
and has so thoroughly altered its matter, is, in truth, the author. It is not
too much to say of the volume before us that it is virtually Mr. Brooke’s compo-
sition. A wonderful hook it is, too. Doubtless there are defects, hut there are
very few treatises which include every department of that terribly wide science,
Physics, which can boast fewer errors or omissions. Extending as it does
over nearly 900 pages of small print, containing more than 700 woodcuts,
and dealing with Mechanics, Hydrostatics, Pneumatics, Sound, Magnetism,
Electricity, Light, and Heat, in regard to both their principles and ancient and
modern application, this manual is a model of careful compilation. It
treats of every question in Natural Philosophy which can be discussed
without reference to a mathematical physics,” and thus forms an excellent
textbook for the student, while its clear description of philosophical
apparatus, and its embodiment of the most recent results of physical research,
render it a useful book of reference for the man of education. We think
Mr. Brooke has spared no pains to seek out the most novel applications
of science for description in his work, and that his efforts have been
decidedly successful. In all that relates to the recent physical discoveries —
such as, for example, Wilde and Siemen’s electro -magnetic machines, Brown-
ing’s spectroscope, Powell and Lealand’s binocular — for high powers, and
so forth, this manual gives complete details. There is only one feature we
find fault with, and that is part of the introduction. Why did Mr. Brooke
indulge in a discussion of the moral aspects of Physics P His observa-
tions, though well intended, are as out of place as they are petulant and
illogical. We allude to the remarks, and not to the aim which prompted
them.

THE FIELD-NATURALIST’S COMPANION.*

HEBE is a little book sui generis. We know of no other of its kind.

Translated from the German of Nave, by the Rev. W. Spicer, a
naturalist well qualified for the task, it tells us how we may search for, when
we may find, how we may preserve, and in what manner we may prepare,
all the cryptogamic beauties which lie in myriads round us, but which so
few of us know aught of. Those who have got a microscope, and wish to spend
a twelvemonth of pleasant u evenings ” at it, should procure this u handy-
book ” and begin their excursions. The author will tell them how to provide
themselves in order to carry on their labours to advantage. We doubt
whether one requires all the apparatus which Herr Nave describes •, but we

treatise of the late Golding Bird, M. A. Sixth edition, London: Churchill.
1867.

* “ A Handy-book to the Collection and Preparation of Fresh-water and
Marine Algae, Diatoms, Desmids, Fungi, Lichens, Mosses, etc.” By Johaun
Nave. Translated and Edited by the Rev. W. Spicer, M.A. London :
Hardwicke. 1867.

VOL. VI. — NO. XXV. I I

436

POPULAR SCIENCE REVIEW.

suppose that he considers his hook would have been incomplete did not
all the paraphernalia of the field-naturalist find a place in his volume. But
whatever view our readers may take on this point, we can assure them that
they will find all the information they require in Herr Nave’s Handy-hook,
and what the text may he deficient in, will he met by the twenty-six ex-
cellent page-plates which are dispersed through the letterpress. The
editor’s notes, though they are not numerous, are concise and useful. The
publisher, it seems to us, would have consulted the convenience of readers
more, had he distributed the illustrations over the text, instead of grouping
them in plates. What is gained in beauty by the better working of cuts
when printed in plates, is lost in time to the student, who is obliged to turn
over leaves oftener than he requires in order to find the figure to which
what he is reading refers. This is the only point which, in our opinion,
needs amendment, and, after all, it is not a very serious one.

SANTONIN: A VOLCANIC CRATER.*

THE islands of the Santorin group have for many years attracted the
attention of those geologists who sought to discover the origin of
volcanoes — who tried to solve the problem of the construction of craters.
Since the recent eruption, so fully detailed in these pages by Professor
Ansted, Santorin has had many European visitors, especially French and
German. These have not only carefully investigated the topographical
features of its islands, but have brought the most subtle instruments of
science to bear upon the volcanic phenomena, in order to arrive, if pos-
sible, at the conditions which govern eruptive discharges. Magnetism has
been especially employed, and has given some startling results. It will be
understood, therefore, that those islands are objects of the highest interest
to the philosophic geologist, who hopes by a careful study of them to unfold
the now mysterious laws controlling the development of volcanoes. The
work which Messrs. Triibner have issued in an English dress comes in good
time, and though its text is neither particularly original nor comprehen-
sively embracing, it is suggestive, and the admirable photographs which
accompany it are invaluable to those who would study this singular series
of islands. These photographs are birdseye views of the Kaimeni (or burnt
islands), and having been taken from carefully-prepared models, they give
an excellent idea of the outline and general conformation of the rocks. The
maps, too, show at a glance that the islands Af Santorin, Thera, and Therasia
are really but portions of a gigantic crater, the remainder of which is now
submerged. This is the opinion held by the authors, and expressed in
somewhat stilted and Germanised English in the work before us. u The
semicircular island of Thera, which, with Therasia and Aspronisi, encloses a
sea-basin of more than five miles in diameter, containing in its centre three
islands of historical date, the Kaimenis (or burnt islands), resemble com-

* 11 Santorin. The Kaimeni Islands, from Observations by K. v.
Kritsch, W. Reiss, and A. Stiibel.” Translated from the German. London :
Triibner. 1867.

REVIEWS.

437

pletely tlie most celebrated volcanoes of Europe, and many of tbe American
continent, as well with regard to its internal structure as concerning its
relation to the modern eruptions. There exists between Thera and the
Kaimeni islands the same relation as between Somma and Mount Vesuvius
— between the Serra di Fogo and a wider cone of 9,000 feet — a relation
which we find again recurring between the Pic of Tenerif and the Canadas
mountains, by which it is surrounded.” This opinion is supported by many
analogies, and is doubtless correct ; but it is not original, having been long
ago pronounced by the great geologist, Von Buch, who looked upon the
whole crater as one of u elevation” rather than of deposition. No one who
has read the history of the late eruption, and who glances at the photographs
and maps of Messrs. Reiss and Stiibel’s work, can fail to be impressed with
the belief that Kaimeni stands in the same relation to Thera and the sur-
rounding islands as Vesuvius does to the Somma ; that is to say, it is the
modern and active eruptive centre, situate within the ancient and extinct
eruptive centre which surrounds it. The maps have been prepared upon the
plan of those published by our Admiralty, but have been drawn to a con-
siderably larger scale, and help to clear up the ideas suggested by the
photographs. We have much pleasure in commending this work to the
notice of our geological readers.

MEDICAL BIOGRAPHY.*

THE work, which was begun in 1865 by the late Dr. Herbert Barker, is
being continued by his friend, Dr. Tindall Robertson. Its object is to
present the public with a series of photographs of the more celebrated phy-
sicians and surgeons of this and other countries, accompanied by short sketches
of the various incidents which have characterised their lives. We regret that
we can only speak from our experience of a single number, but, in so far
as our own judgment goes, the editor and photographers have discharged
their respective duties with credit to themselves and satisfaction to their
subscribers. Dr. Robertson appears to show no partiality either in the selec-
tion of his biographical subjects or in his method of treating them. The
examples chosen in the number before us, — Drs. William Augustus Grey,
Robert Gardiner Hill, and Mr. R. W. Dunn, — are all distinguished members
of the profession ; and the history of the successive labours by which they
raised themselves from mediocrity to fame, has been truly and pleasantly
given by the editor. Dr. Robertson avoids, as far as possible, those lauda-
tory digressions in which so many biographers indulge, and endeavours to
state facts without giving them more than their natural colours. In this he
has been successful, and the result is therefore eminently satisfactory. In the
pages of this work readers will find all the important facts in the history
of our “eminent medical men” stated with clearness, accuracy, and

* 11 Photographs of Eminent Medical Men of all Countries, with Analytical
Notices of their Works.” No. 5, Vol. II. London : Churchill.

I I 2

438

POPULAR SCIENCE REVIEW.

honesty ; and when they turn from the letterpress to Mr. Ernest Edwards*
excellent photographs, they can put the seal of association upon the facts
they have gathered from Dr. Robertson’s ably- written memoirs.

THE CONSTELLATION SEASONS.*

MR. PROCTOR here gives us a series of thirteen carefully-drawn maps, re-
presenting the relative position of the various constellations for nearly
every night in the year. These maps do not, of course, contain all those
astronomical details which are to he found in a perfect star-map. Such details
would have been out of place ; the object of the author being to supply the
amateur astronomer with a picture of the heavens at certain hours, so that
he may study the more important star-groups. Each map contains the whole
of the visible heavens at the hour and date mentioned beneath it, the centre
being the point over the head of the observer, and the outline indicating the
horizon. Each star is marked in its proper direction as regards the point of
the compass, and is placed at its true geographical distance from the centre.
Hence the student commencing observations at the hour and date of the
map, soon makes himself familiar with all the constellations. The maps
include stars of the fourth magnitude, and by an easy calculation they may be
employed for other nights than those for which they are intended. In our
early studies of the constellations we had only the assistance of Lardner
maps, and we can therefore fully appreciate the value of Mr. Proctor’s
excellent series.

HOW TO MAKE A STEAM-ENGINE, f

nET7E remember that one of the earliest and one of the most cherished
* ' ambitions of boyhood was the construction of a model steam-engine.
This desire is by no means an uncommon one, and may, we believe, be
classed with that all-pervading fancy of some boys, that to be a sailor is to
enjoy the very acme of mortal happiness. The little book before us is
intended to supply ambitious youth with the information necessary to
understand a working locomotive, and to manufacture a model steam-
engine. The elementary sketch of the history of the discovery of steam
as a motive power is simple and tolerably free from error, but we fear that
boys will find it difficult to understand a “ stoker’s” explanation of the
principle on which u Barker’s mill ” revolves. To say that the rotation is
dependent on u the well-known principle in mechanics that action and
reaction are equal and in contrary direction,” is simply to put a stumbling-
block in the young reader’s path. It is even worse, for it is no explanation

* u The Constellation Seasons : an Easy Guide to the Knowledge of the
Stars.” Edited by Richard A. Proctor, B.A., F.R.G.S. London : Longmans.
1867.

t u The Model Steam Engine : How to Buy, How to Use, and How to
Make it.” By a Steady Stoker. London : Houlston & Wright. 1867.

IIEYlEVrS.

439

at all, the key to the movement being the inequality of pressures. The
description of the method of making a model steam-engine, however simple
it may seem to a stoker, could not be followed even hv a boy who possessed
considerable mechanical skill. We think, therefore, that however laudable
the aim of this little work, the author has failed completely in its execution.

ARITHMETIC SIMPLIFIED.*

TPIE four rules of simple arithmetic, and vulgar and decimal fractions, are
dealt with most intelligently by the author. The book is intended as a
supplement to Dr. Arnott’s treatise on Physics, and for the use, not of be-
ginners,but of those who have in some measure forgotten what they have
learned. We know a good many well-educated people who cannot, never-
theless, add together half-a-dozen vulgar fractions, and to whom a decimal
fraction is somewhat of a mystery j to those we commend this volume.
It is very simple and intelligible.

WEATHER SCIENCE. f

OF the degeneration of weather-students since the death of Admiral Fitz-
roy, we have ample proof in the abundance of works like the present
one which come under our notice. In the book upon our table we find a
number of papers, some with authors’ names and some without, but all
expressive of the ignorant dogmatism and flippant presumption which are
characteristic of senility in its most intolerable stage. The intense imper-
tinence and utter superficiality of their composition is evinced in the following
quotation from a paper by a lady whom an adoring editor styles the “ pioneer
of modern physical astronomy — “When good sense has banished pedantry,
and astronomy details celestial movement according to fact , the noble
simplicity of the science will become apparent; and the object of most of
the phenomena within our solar system will form one and the same with the
actuating principle of the universe — viz., the accumulation of renovating repro-
ductiveness. The planets then, ceasing to be considered as mere retrograding
or stationary puppets, will be registered as independent orbs in the constant
interchange of mutual renovations.” We pause in astonishment to think
what would become of Miss Burton’s “ accumulation of renovating repro-
ductiveness,” were common sense even now to banish pedantry. There must
indeed be a 11 noble simplicity ” of mind in those who, like our editor, can
believe in such disgusting and inane verbiage as the above. There is only
one word in our language which expresses its value, and that word is
Rubbish !

HANDBOOK OF PRACTICAL TELEGRAPHY. %

IN our notice of the first edition of this work we spoke in favourable terms
of the method pursued by the author in the treatment of his subject.

* “Arithmetic Simplified.” By Neil Arnott, M.D., F.R.S. London: Long-
mans. 1867.

t “ The Science of the Weather ; in a Series of Letters by several Authors.”
Edited by B. Glasgow : Laidlaw. 1867.

t “ A Handbook of Practical Telegraphy.” By R. S. Culley. Second
edition. Longmans. 1867.

440

POPULAR SCIENCE REVIEW.

In the present edition we perceive that many new features have been intro-
duced, and that the hook has been considerably enlarged. Dealing as it does
with the construction of the different varieties of telegraph, and with the
most approved means of constructing lines and supplying galvanic force, it
is a work which must be especially valuable to electric enquirers and tele-
graph superintendents. It will be found the textbook of reference, indeed
the only one, on its subject.

Beliquce Aquitanicce , Contributions to the Archceology and Palceontology oj
Perigord. By Edouard Lartet and Henry Christy. Part IV. London : Bailliere.
1867. — This number reached us too late for notice in our last issue. Like
the former, it is edited by Professor Rupert Jones. It continues the subject
dealt with in No. III., and treats also of the geology of Vezere. The wood-
cuts in the text are good, and the plates, six in number, are admirable works
of art. They are brought out in Paris by Louveau and Becquet, and surpass
in excellence illustrations produced in this country.

The American Naturalist. Essex Institute, Salem, U.S.A. — Of this
monthly periodical we have received the numbers from March to August,
with the exception of that for May. It is a new venture, devoted to the
interests of General Natural History, and is creditable alike to its editor and
publisher. The papers, though not upon strikingly original questions, are of
much popular interest, and are, we perceive, written with a due avoidance
of technicalities. The illustrations to the paper on Polyzoa and Jelly-fishes
are accurately and artistically executed ; the plate accompanying Dr.
Packard’s article on the Dragonfly being a perfect type of Natural History
drawing. The reviews are written with care, and display a thorough im-
partiality. We welcome our new contemporary, and we hope to profit by
his gleanings from the vast American fields of Natural Science.

Clinical Lectures on Diseases of the Skin. By Balmanno Squire, M.B.,
F.L.S. London : Churchill. 1867. — Mr. Squire is issuing a new and larger
edition of his valuable photographs of skin diseases. The work will be com-
pleted in thirty- six monthly parts, and the first four numbers are now before us.
Each photograph is coloured, and refers to a particular case, typical of the
disease it represents, and is accompanied by two pages of letterpress, which
give the clinical history of the affection. For ourselves, we are dis-
posed to think that the uncoloured photograph is more useful than the
coloured one, and infinitely more reliable, but doubtless on this point we
are at issue with most dermatologists. The series is, in any case, most
creditable to the author, and will be equally servicable to the physician.

We have received Readwin’s Index to Mineralogy. Spon. — Summary
Notes of Vegetable Anatomy and Physiology. By Louis C. Miall. Simpkin &
Co. — Causes of Motion in Matter. By Thomas Ayers. Simpkin. — The Quad-
rature and Rectification of the Circle. By James Smith, Esq. Liverpool :
Howell. — The Alleged Hydrothermal Origin of Rocks. By D. Forbes, F.R.S.
— The Development and Succession of Teeth in the Mammalia. By W.
H. Flower, F.R.S. — Remarks on the Genus Pyrula. By T. Graham Ponton.
— On the Change in the Obliquity of the Ecliptic, and its Effects. By James
Croll, Esq. — A Technical Institution for Leeds. By G. N. & A. Nussey. —
The Akazga Bean. By Dr. T. R. Fraser, F.R.S.E.

441

SCIENTIFIC SUMMARY.

ASTRONOMY.

nnilE Meteors of the 10 th"of August , 1867. — Tlie 'observations wbicb were
made at Rome have been reported to the French Academy, in a paper
communicated by Father Secchi on the 2nd of September. The author regrets
that his observations are not so complete as they might have been, owing
to the fact that the epidemic of cholera caused many of his assistants to
leave Rome. The following are the results arrived at when the Moon’s
light was sufficiently dim to allow observations to be made : —

h. m.

August 11th. 2 11

2 25

2 46

3 00
3 20
3 30

to b. m. Number of meteors.

„ 2 25 15

„ 2 46 16

„ 3 00 15

„ 3 20 21

„ 3 30 8

., 3 45 11

Thus 86 meteors were seen in ninety-four minutes. On the following day
the numbers were as follows : —

b. m. to b. m. Number of meteors.

3 15 „ 3 30 15

3 30 „ 3 45 11

3 30(F),, 3 46 3

“Thus, there were 29 meteors observed in thirty-one minutes.” The
hourly numbers of the two days were respectively 54-9 and 42-6. The
meteors seemed to radiate from the space between Perseus and Cassiopeia,
but many of them were sporadic.

A Stellar Spectroscope of extreme simplicity, and which may be adapted to
any ordinary telescope, has been devised by Signor Secchi. Amateurs may
henceforth, therefore, pursue spectroscopic investigation of the stars with
a considerable degree of accuracy. The combination he has devised consists
of a prism and cylindrical lens, and forms a spectroscopic eyepiece. M.
Secretan adapted it to a telescope with an aperture of only 95 millimetres,
and with this arrangement Signor Secchi was able to observe and examine
the principal spectral bands of stars of the 1st and 2nd magnitude.
a-Herculis and /3-Pegasus were examined with ease, and the atmospheric
rays of the planet Jupiter were clearly seen.

The August Meteors have also been examined by MM. Coulvier-Gravier
and Chapelas, who have come to a different conclusion to that of M. Secchi
as to their relative number in this and in former years. These observers

442

POPULAR SCIENCE REVIEW.

gave the result of tlieir observations on the sliooting-stars during the nights
of the 9th, 10th, and 11th of August of this year. They showed, by a
tabular statement, that from the 5th of August, the mean hourly number
at midnight in a clear sky — that is to say, corrected for the lunar light and
the presence of clouds — was 16'2 stars; this became 33-7 on the 9th, 49-9
on the 10th, and 28’7 on the 11th, giving an average of 374. Comparing
this with the year 1848, which had given, for the mean hourly number,
110 meteors, it seems that the quantity diminishes very sensibly.

Behaviour of the Aneroid Barometer. — On this subject a very valuable
paper was read by Dr. Balfour Stewart at the recent meeting of the British
Association in Dundee. Experiments had lately been made with the view
of ascertaining to what extent an aneroid may be considered a reliable in-
strument when exposed to considerable changes of pressure, such as occur
in mountain districts. By means of an air-pump, the aneroids, when
placed in a receiver, may be subjected to any pressure. A method of tap-
ping the aneroids had also been devised, and by this means the experiments
as to the deviation of the results given by these instruments were conducted
with comparative ease, and with the greatest accuracy. The experiments
are still going on. Sir William Thomson, in commenting on Dr. Ste-
wart’s communication, said the aneroid had become so popular an instru-
ment, that many had satisfaction in learning that it was capable of giving
results with scientific precision. Dr. Stewart had shown that in taking a
barometer up a mountain of 12,000 feet, the error would only be about
300 feet, and had also shown how to correct this error. By carefully using
these instruments, therefore, they had a probability of determining, with
much less probability of error, the height of a mountain of 12,000 feet.

Lunar Maps. — Mr. Birt recently issued two lunar maps, in red outline,
with all the present known objects marked, in order that those who
find any variation in the objects may mark them in black. These maps,
which contain 203 objects, are on a scale of 200 inches to the Moon’s
diameter, and comprise the space included between 0° and 6° West longi-
tude, and 0° and 10° South latitude.

The Memoirs of the Astronomical Society. — It is stated that the Council
of the Boyal Astronomical Society have resolved that in future the Memoirs
of the Society shall be given to all Fellows applying for them, and that
this regulation will commence with the volume preparing for the current
year. The subject has occupied the attention of the Council on several
occasions before, but the expense was considered too great.

The Dusky-ring of Saturn. — Mr. G. E. Chambers, having made a mis-
statement in regard to the history of the discovery of the u dusky-ring,”
writes to the editor of the Astronomical Register to correct his mistake.
The erroneous paragraph appears on page 129 of Mr. Chambers’s Descriptive
Astronomy, and is as follows : — u On December 3, Lassell, while on a visit
to Dawes, saw 1 something like a crape veil covering a part of the sky
within the inner ring.’ This observation, it would stem, was not made in
consequence of any hint given by Dawes as to what he himself had seen, so
Lassell must be regarded as a third or (reckoning Galle) a fourth inde-
pendent discoverer.” Mr. Chambers makes the following explanation : — “I
have satisfied myself that the passage italicised is entirely the reverse of

SCIENTIFIC SUMMARY.

443

the truth, and that Mr. Lassell has no claim to he regarded as an indepen-
dent discoverer. I was misled "by depending on the Monthly Notices of the
period, and by the phraseology adopted by Mr. Lassell in communicating to
the Society his account of certain observations made by him in company
with Mr. Dawes.”

The Lunar Crater Alhazen has often been a puzzle to selenographers, from
the various appearances it has presented to observers, and from its general
indistinctness. Recently, however, it has been very satisfactorily observed
by Mr. W. R. Birt, F.R.A.S., who had previously (vide Monthly
Notices, vol. xxii., p. 230) given considerable attention to the subject. In
his earlier account of the appearance, Mr. Birt was unable to give a descrip-
tion of the crater. On the 5th of July last, however, at 9 p.m., he saw
the crater under very favourable circumstances with the Royal Society’s
achromatic of 4| inches aperture, power 230, Schroter’s pair of craters y and
$ in its neighbourhood being very distinct (see Astronomical Register , No.
xliii., July 1866, p. 188). He then ascertained that Schroter’s Alhazen is
really a crater situated on the surface between the two ranges of mountains,
and but slightly depressed below it. Although not greatly depressed, it is
sufficiently so to present, under this illumination and visual angle, the true
crater-form. It would seem, says Mr. Birt, that its apparition as a crater is
rare , probably from a variety of causes. It is quite of sufficient magnitude
to have been seen with an aperture of 2| inches, and it would be very im-
portant to ascertain if, under nearly similar circumstances to those of July
5, 1867, it would present a similar aspect. “ The selenographical conditions
of its visibility on July 5 were as follows Morning illumination, after
Perigee, 102 hours ; before Apogee, 215 hours. Eastward of its mean
position in longitude, Moon’s latitude, S. 0° 43' 55", a little southward of
its mean position in latitude. For illumination, longitude of termination,
W. 42° 12' 54", angle of terminator and meridian — 1° 23'. South pole of
the Moon in sunlight 25 days after the winter solstice in the Moon’s
northern hemisphere.”

Neivly-discovered Comes of Vega. — An observer (R.C.) states that Mr.
Buckingham, of Walworth Common, has discovered two new comes, much
closer than those so well known to astronomers. R. C., who ought to have
given his name in full, states that, on being asked by Mr. Buckingham to
examine Alpha Lyra, and in turning the telescope to the star, he saw one
of the stars which Mr. Buckingham had already discovered, and described
the position and the distance by comparison with the known distance of the
companion-star, fixing it at five or six seconds. These data coincided with
Mr. Buckingham’s. But, owing to the fitful and unsteady atmosphere, it
was some time before he was able to catch up the second companion, which
seemed fainter and somewhat more distant. He believes that Mr. Bucking-
ham first discovered these two companions with his 20-inch refractor, and
was able afterwards to verify his discovery with the 9-inch equatorial in
which he saw them ; but, though he recorded the fact at the time, he did
not publish his discovery. As he was also able to see the companions
clearly, and tested the sight by turning consecutively half-round the eye-
piece and object-glass with the same result, and as he has no doubt pos-
sessors of similar telescopes will be able to make them out easily, it seemed

444

POPULAR SCIENCE REVIEW.

to him that a discovery of such a system attending Yega should he made
known, as of course it would he invested with an interest second to none in
the list of double stars.

The total Solar Eclipse of 1863. — At the meeting of the British Association,
Sir Andrew Waugh read a paper by Major Tennant, regarding the steps
that are being taken by the Indian Government- to ensure extensive and
correct observations of the coming eclipse. The eclipse in question will
he seen to great advantage, and the arrangements that were being made
gave promise of valuable results. The Secretary of State had sanctioned
the proposal to send out to India some of the best instruments in this
country. It was intended, among other obaservtions, to photograph the
appearances presented, and for this purpose a large telescope was to he
erected. Provision had been made for obtaining a considerable field of view,
in order that, if possible, some record might be obtained of the structure of
the corona. The Astronomer Royal had lent a 42 -inch telescope, with an
eyepiece, for the examination of the lines of the corona, and altogether the
preparations which Major Tennant was now in London superintending led
them to believe that valuable results would be obtained by the observation
of this eclipse. It was stated by Mr. W. Ladd, who was present, that the
arrangements of Major Tennant for the polarising eyepiece for the telescope
were very simple. He had been constructing one of these for Major Tennant,
and also for Mr. Huggins, and he thought that no astronomer should be with-
out this polarising apparatus. It might be easily attached to the eyepiece
of ordinary telescopes.

The Kew Photo-Heliograph. — According to the recent Report of the Kew
Committee, it appears that the heliograph, which is in charge of Mr. De la
Rue, continues to be worked in a most satisfactory manner. During the
past year 204 negatives have been taken on 144 days. Pictures of the
Pagoda in Kew Gardens are regularly taken by this instrument, in the hope
that by this means the angular diameter of the Sun may be satisfactorily
determined. Since the meeting of the British Association in 1866, a second
series of solar researches, in continuation of the first series, has been pub-
lished (the expense of printing having been defrayed by Mr. De la Rue),
entitled 11 Researches in Solar Physics, Second Series, Area Measurements
of the Sun-spots observed by Mr. Carrington during the seven years
1854 -1860 inclusive, and Deductions therefrom 5 by Messrs. De la Rue,
Stewart, and Loewy.” The heliographic latitudes and longitudes of all
the spots recorded by the Kew Photo-heliograph during the years 1862 and
1863 have been calculated, and it is hoped that the results may soon be
published, forming a third series of Polar Researches. It is believed that
these results will demonstrate the superiority of photographic pictures over
all other methods of observation. The sum of 60/. has been obtained from
the Government Grant Fund of the Royal Society to be applied to the
discussion of Hofrath Schwabe’s long and valuable series of sun-spots at
present in the possession of Kew Observatory. These pictures are now being
examined with this object. Sun-spots continued likewise to be numbered,
after the manner of Hofrath Schwabe ; and a table, exhibiting the monthly
groups observed at Dessau and at Kew, for the year 1866, has already ap-
peared in the Monthly Notices of the Astronomical Society, vol. xxvii.,
No. 3.

SCIENTIFIC SUMMAKY.

445

The late Lunar Eclipse. — A partial eclipse of tlie Moon took place on tlie
13th. of September. It commenced at about twenty minutes to ten. The
following was the order of appearances : —

h. m.

First contact with the penumbra 9 43-3 Greenwich mean time.

First contact with the shadow . 10 57*4

Middle of the eclipse . .12 26-2

Last contact with the shadow . 13 55 -0

Last contact with the penumbra 15 9T

Magnitude of the eclipse (Moon’s diameter=l), 0693.

Aqueous Vapour in the Stars. — M. Jansenn announces an important dis-
covery which he has just made — viz., that in a spectrum-analysis of some of
the stars, he has seen bands which indicate the presence of aqueous vapour
in these bodies. He observed this especially in the case of the spectrum of
Antares. In order to avoid any error through the presence of atmospheric
vapour, M. Jansenn conducted his experiments at Etna, where the air is
remarkably rare and dry. Researches made at Palermo and Marseilles
lead him to conclude that there is water-vapour in the atmosphere of both
Mars and Saturn.

The labours of the Lunar Committee have formed the subject of some
interesting comments by Mr. Glaisher. The method in which the work is
distributed among the several observers is admirably adapted to meet the
ends aimed at by the Committee. The areas are divided into subzones of 1
deg. of latitude, and they are allotted to observers in such a way that, by
each pair overlapping and dovetailing into the adjoining pairs, every object
shall be brought under the eyes of two independent students. It is
proposed that the returns which the Committee may receive shall be ex-
amined by Mr. Birt, with the aid of a telescope of superior power, after
which the state of the objects so examined is to be regarded as authorita-
tively fixed for the epoch of examination. The most difficult part of the
study of the Moon’s surface is that of delineation. No two drawings of the
same object will ever agree in all the details, and a series of drawings of the
same object will manifest very considerable departures from one made at
the period of mean libration, which occurs once only in three years. In
arranging the formulae for the computation of the librations of the centre of
the apparent disc, Professor Challis, of Cambridge, has rendered this Com-
mittee essential service. In preparing Appendix II. in the last volume of
reports, which includes libration, Mr. Birt has given (from tbe Berliner
Astronomisches Jahrbuch fur 1843), the derivation, as arranged by Professor
Challis, of the Formulae for Libration, inserted on p. x. of the Nautical
Almanac, and also the formulae employed by Lohrmann in the computation
of points of the first order, including those for libration. The difficulties
attendant upon the delineation of the surface being so great, the Committee
has not ventured beyond the simple outline of the two areas already issued.

The Crater LJnne. — The observations upon this singular crater which have
been made from December 12, 1866, up to June 11, 1867, have now
been published, and show how advanced is our knowledge of seleno-
graphy. As Mr. Birt stated at the British Association, three features in

446

rOPULAll SCIENCE REYIEW.

Linne are especially to be noticed : — 1. A large ill-defined white spot ;
2. A shallow saucer-like depression, very rarely seen; and 3. A small
crater, first Seen December, as a white hill or black spot — the white hill
being tlie edge of the crater just catching the sun’s rays, and the black spot
the shadow. In the Circular No. III. of the Lunar Committee, there is
an account of the observations of this small crater, or fine black point, as
seen by Schmidt, Buckingham, Secchi, Respighi, and Wolf. The largest
estimation (Secchi’s) of the diameter of this crater previous to April 1867 (viz.,
Feb. 11, 1867), is 033", or 2-352 English feet. It appears from Respighi’s
communication ( Bulletin Meteorologique de V Observatoire du College Homain ,
31st May, 1867), that he observed in April and May, with the equatorial of
the Capitoline Observatory, Rome, by Merz, of 4-5 inches (French) aperture,
all the main features that have been recorded by Schmidt and others since
Oct. 16, 1866 — viz., the whitish cloudlike spot of nearly the same extent as
the crater Sulpicius Gallus ; the ring of a large crater of small depth,
probably the ring seen by Messrs. Knott and Webb ; the bright point west
of the centre of the large white spot, which he found (as the English
observers) to be the western border of the small crater ; and the small crater
itself, to which he gives a diameter of 4-0", or 28,224 English feet. Wolf
estimates the diameter at a little less than DO", or 7,056 English feet.
Whatever may be the truth in the midst of the conflicting opinions which
have been expressed on the state of Linne (there are no discrepancies in the
evidence), it is certain that no lunar spot has received so much attention
from so many observers as Linne , and that its features are so well determined
(with the exception of the diameter of the small crater, 0-33" in February,
4-0" in April and May, DO" in June, which, by the way, are not contra-
dictory), for the early half of the year 1867, as to furnish reliable evidence of
its condition at this epoch. It must be mentioned that Mr. Rutherford,
whose observations have been carried on at the other side of the Atlantic,
and whose photographs are said to be larger than ours, states that he
has been unable to detect any change in the brightness of the locality in
question.

The Spectrum of Meteors. — It was stated by Professor Herschel at Dundee,
that though the spectroscope showed a yellow light in the case of meteors,
it was impossible to say what was the composition of this light. As
observers multiplied, however, with telescopes armed with spectroscopes,
this difficulty would no doubt be resolved. The connection between comets
and meteors had this year been established without doubt, and that
connection gave wide scope for speculation as to the origin and character of
meteoric bodies. Mr. Huggins had made an observation of the light of a
comet, and although that observation was not perfect, still it was sufficient
to identify the light of the nucleus of the comet with that of the meteoric
bodies. There were two theories as to these meteors. Leverrierhad shown
that their orbit extended from that of Uranus to that of the Earth, while
an Italian astronomer believed that they came from the utmost fields of
space. Fifty-six showers were well established ; and it was by the study of
these showers that they hoped to continue, and possibly confirm and extend,
their researches by the assistance of those zealous observers who had hitherto
been their supporters and constant assistants among the members and other
observers of this Association.

SCIENTIFIC SUMMARY.

447

A new Planet, which, has been named Undina, has been simultaneously
discovered by Peters, of Hamilton College, U. S., and Tietjens, of Berlin.
Its magnitude is between the 10th and 11th, and it was first seen on the
7th of July last. This is, then, the 100th or> according to those who
believe in the existence of a planet within Mercury’s orbit, the 101st planet.

Jupiter without his Satellites. — In our last number Mr. Proctor gave our
readers ample notice of this singular phenomenon, and we are glad to find
that many of them availed themselves of the opportunity noted. The editor
of the Astronomical Register says that when the five black spots were pro-
jected in the line of the belts, they gave one the idea of “a bar of printed
music.”

The Meteorlike Bodies near the Sun , which were described by Mr. Lowe
and Mr. Bird, are alleged by Mr. C. L. Prince to have been nothing more
than seeds of dandelion, floating through the atmosphere. The direction of
these pseudo-meteors will be always found to coincide with that of the
wind.

Change of Focus in observing Stars. — The change of focus which is said
to be requisite in the examination of stars widely separated in altitude, has
been inquired into by Captain Noble, who lately laid a paper on the subject
before the Boyal Astronomical Society. We conclude, from his observations,
that in the finest state of the atmosphere the foci of all stars are identical.
But he says that when, as in the normal state of things, there is an appreci-
able amount of vapour near the horizon, a shortening of the focus of a
telescope, directed to objects in its neighbourhood, may take place. — Vide
Monthly Notices, June 14.

The Expansion of Brass Pendula. — Major Tennant publishes a singular
paper on this point. It would seem, from the evidence adduced by the author,
that at a pressure of only five inches of mercury the coefficient of expansio11
of the brass pendulum must not only be increased, but appears to be 13 per
cent, greater than ever before has been assigned to brass.

Comets and Meteors. — In a paper on this subject, laid before the last
meeting of the Astronomical Society, Mr. G-. J. Stoney, Secretary to the
Queen’s University in Ireland, make the following interesting observations,
which tend to show, as Schiaparelli has already pointed out, that there is a
very natural relationship between comets and meteors. If interstellar space,
external to the Solar System, be, as is most probable, peopled with innumer-
able meteoric bodies independent of one another, a comet while outside the
Solar System would in the lapse of ages collect a vast cluster of such
meteorites within itself. Each meteorite which approached the comet would
in general do so in a parabolic orbit ; and, if it came near enough to pass
through a part of the comet, this parabolic orbit would, by the resistance of
the matter of the comet, be converted into an ellipse. The meteor would
therefore return again and again, and on each occasion that it passed through
the comet its orbit would be still further shortened, until at length it would
fall in, and add one to whatever cluster had been brought together by the
previous repetitions of this process. In this way a comet, while moving in
outer space, beyond the reach of the many powerful disturbing influences
which prevail within the Solar System, would inevitably accumulate within
itself just such a globular cluster of meteorites as the November meteors
must have been before they became associated with the Solar System.

448

POPULAR SCIENCE REVIEW.

The Nebula of Orion. — Father Secchi has presented to the French
Academy a drawing of the nebula of Orion, which was lately prepared at
the Roman College, and which he proposes to publish on his return to Rome.
Spectrum-analysis of the nebula proves it, like its fellows, to be composed
essentially of some gaseous compound.

The Pascal-Newton controversy still continues. Mr. Chasle still contends
that the documents in his possession are genuine. On the other hand, Sir D.
Brewster and Mr. Faugere hold that they are forgeries. The arguments of
Sir David seem invincible, but Mr. Chasle’s most recent communications to
the Academy show that he is undaunted. The question whether Newton or
Pascal discovered the law of gravitation cannot, therefore, be regarded as
definitely decided.

BOTANY.

The Moving Corpuscles of Vdllisneria. — In a paper read before the Philoso-
phical Society of Manchester on the 18th of July, Mr. J. Gr. Lynde describes
some recent observations made by him with a view to discover the cause
of the motion of the corpuscles. The result arrived at seems to be that
cilia are most probably present. Mr. Lynde does not positively assert that
this is the case, but he contends that it is most probable. After various
fruitless experiments, he determined to try the effect of polarised light.
Having produced a dark-blue ground by one of Darker’s selenites, he put
on a ^-inch object, and examined a portion of the leaf, in which the circu-
lation was rather sluggish. All over the surface of the cells he perceived
“ brilliant gold-coloured scintillations which had all the appearance of
cilia in motion, and repeated observations showed precisely the same phe-
nomena.” Notwithstanding all that he has seen, he cannot say that he is
convinced the appearances can be attributed to nothing else but cilia ; it is
possible they may be due to the presence of active corpuscles — as suggested
by Mr. Wenham in his paper on the Leaf-cells of Anacharis Alsinastrum,
published in the Microscopical Journal for 1855 — which corpuscles may be
Vibrions, described by Dr. Cohn in his u Researches on the Development
of the Microscopic Algae and Fungi/’ as representing the developmental
condition of a plant, but it is only by further research that this point
can be definitely settled. The result of his observations so far appears
to be that in addition to the wave of light already seen, the separate
objects causing that wave may now be observed in the manner described.
"What these objects are is still a matter to be determined, but at present Mr.
Lynde is inclined to believe them to be cilia on the cell- wall, while at tfip
same time there are also independent moving corpuscles within the cell ;
some of these bodies have the appearance of crystals, and in one specimen
a great number of starch-granules in the cells were observed.

A Cure for Dry-rot. — The terrible destruction of timber caused by the
spread of the fungus known as Merulius lachrymans leads us to record any
suggested mode of preventing the propagation of the fungus. The mode
most recently recommended is that which Mr. Lunge refers to in a letter
in the Chemical News. Mr. Lunge thinks that the dry-rot is generally intro-
duced into houses with the clay which is so often employed for filling the

SCIENTIFIC SUMMARY.

449

spaces between the joists and branding of a chamber-floor. He thinks,
therefore, that by filling this space with a material which destroys the
fungus, the prevention of dry-rot may be effected. The substance which
he considers especially effective for the purpose is the tank-waste from
alkali-works. This, he says, u may be had at all alkali- works for carting
away.”

Hawaiian Plants. — A critical list of the plants of the Hawaiian Islands
is being brought out in the Proceedings of the American Academy by Mr.
Horace Mann. This is not, however, the first. Indeed, it must only be
regarded as a supplement to the fine work which was executed by Dr.
Berthold Seemann, the editor of the Journal of Botany.

No new Genera of Plants in the year 1900 ! — In a curious statistical paper
read by M. de Candolle at the International Botanical Congress, the
author expressed his belief that by the end of this century botanists will
have become acquainted with every genus of plants on the face of the
globe, and will thenceforth occupy themselves with only species and
varieties. The facts on which M. de Candolle bases this opinion is, that
the number of new genera has diminished in a certain arithmetical order,
while the number of plant-seekers has proportionally increased.

The Fall of the Leaf. — M. Trecul has recently presented to the French
Academy a most valuable series of memoirs on the structure of the u proper
vessels ” of the order Terebinthaceee. In concluding one of his recent
memoirs, he calls attention to a phenomenon which occurs just before the
fall of the leaf, and which is not unlike the process which accompanies the
shedding of horns in animals. It consists in the obstruction of the
li proper ” vessels at the base of the petiole (foot-stalk). This obstruction is
effected by the multiplication of cells, which first shows itself in the parietes
of the vessels. The cells increase and multiply until at last the vessels
are completely choked up in the neighbourhood of the insertion of the
leaf, although in other portions the vessels retain their normal characters.

The Contractions of the Sensitive Plant. — These have formed the subject of
two essays published in the Comptes Bendus for July and August, and
written respectively by M. P. L. Bert and M. de Blondeau. The chief
conclusion at which Mr. Bert arrives is, that the natural and regular move-
ment of the leaves is produced by a different cause from that of sudden
contraction resulting from contact with the fingers. Ether seems to have no
effect upon the former, but it produces an anaesthetic effect which prevents
the latter. M. Blondeau’s enquiries are more important. M. Blondeau
experimented on the plants with the induced galvanic current of a B.uhm-
korfi’s coil. He submitted three plants to the influence of the electric
current. The first was operated on for five minutes ; the plant when left to
itself seemed prostrated, but after a while (a quarter of an hour), the leaves
opened, and it seemed to recover itself. The second was acted on for ten
minutes. This specimen was prostrate for an hour, after which it slowly
recovered. The third specimen was galvanised for twenty-five minutes, but
it never recovered, and in twenty-four hours it had the appearance of a
plant struck by lightning. A fourth plant was etherised, and then
exposed to the current. Strange to say, the latter had not any effect, the
leaves remained straight and open j thus proving, says M. Blondeau, that

450

POPULAR SCIENCE REVIEW.

the mode of contraction of the leaves of the sensitive plant is in some way
allied to the muscular contraction of animals.

The International Botanical Congress was held at Paris on the 16th.
The meeting was held in the rooms of the Imperial Society of Horticulture,
and was presided over by M. Alphonse de Candolle. Almost every
European country was represented.

The Fossil Plants of Bilin. — Herr Ettingshausen has published the third
part of his fossil flora of the Tertiary basin of Bilin, in Bohemia. He treats
of about thirty-four orders of plants belonging to the locality, and alleges
that in great part the genera are the same as those which are now found
living in the neighbourhood.

A new Conifer from Arctic America is described by Mr. Andrew Murray,
in the Journal of Botany for September. The plant, which was referred to
Abies alba by Hr. B. Seemann, was first found by him and Lieutenant
Bedford Pirn, and specimens of its wood may be seen in the Museum at
Kew. It is the most northerly tree met with in the north-west coast of
America, being found in a latitude nearly seven degrees farther north than
the limit of trees on the eastern side of the American continent. Some of
the trees measured from twenty to fifty feet in height, and from four to five
feet in circumference.

Adiantum Capillus-Junonis. — This rare species of maidenhair fern has
been hitherto imperfectly described. "We are glad, therefore, to receive
a more accurate and complete description of it from Dr. H. F. Hance, who
has lately found some fine specimens growing in’ the interstices of the
bricks in the vails of the city of Canton. It seems to resemble rather
closely A. lunulatum, but is nevertheless quite distinct from it. The species
was originally described by Dr. Hana (in Annales des Sciences Naturelles)
as the A. Cantonense ; but the fact that an identical species found at Pekin
had been styled by Dr. W. S. Williams A. Capillus-Junonis , induced the
author to employ this latter specific name instead of Cantonense.

An edible Fungus from Tahiti is described by Mr. Brander as being an
article of commerce in the South Pacific Islands. It grows upon decayed
trees, and is called Teria iore , or rat’s ear, by the natives. This fungus was
first collected in 1863, and is said to fetch twenty cents per pound in
China, where it is used in preparing certain soups.

A Memorial of Sir W. Hooker is about to be erected in Kew Church. It
consists of a tablet enclosing a cast in Wedgwood- ware of Mr. Woolner’s
medallion of the late Sir William Hooker. The medallion occupies the
centre of a composition of panels that are decorated with ferns, etc., in
relief, the fronds being arranged so that their lines harmonise with their
position on the monument ; the panels are divided and mounted in mould-
ings of white marble. The tablet is the work of Mr. It. Palgrave, and is
considered exquisite in design and execution.

The presence of Gases in Plant-tissues. — At a recent meeting of the Botanical
Society of Edinburgh, a most interesting paper was presented by Messrs.
Faivre and Dupre. The plants especially examined by the authors were the
mulberry and the vine, and the following are the conclusions arrived at : —
1. The presence of gases in the interior of the root, of the stem, and of the
branches in the mulberry and vine, is a normal and constant fact. — 2. The

SCIENTIFIC SUMMARY.

451

■composition of these gases changes with the epochs of vegetation. — 3. During
the period of inactivity, carbonic acid is in very small proportion, and is
scarcely appreciable. Oxygen is present to the same extent as in atmospheric
air. During the phase of activity the contrary takes place, and the changes
are more marked in proportion as the vegetation is more energetic ; with
the progress of vegetation, the proportion of oxygen diminishes. — 4. In the
roots, during the epoch of vegetation, the quantity of oxygen is not so great,
while that of carbonic acid is greater than in the branches examined under the
same circumstances. — 5. In the branches, as in the roots, there is an inverse
relation between the oxygen and the carbonic acid ; by adding to the normal
oxygen that disengaged under the form of carbonic acid, we obtain a number
which is scarcely above the proportion of oxygen in the air. — 6. In the mul-
berry and the vine, injections do not penetrate the pith or the bark, whether
in the branches or roots. The ligneous layers are alone permeable to
mercury. The more the formation of vessels increases, the easier and more
complete are the injections. The injections are fuller in the roots than the
branches ; they are also more in the branches than in the young herbaceous
shoots. In the old stems of the mulberry, the central layers cease to be
permeable. — 7. Microscopic examination proves that the injection specially
penetrates the’ pitted and reticulated vessels, and also the spiral vessels in
the young herbaceous shoots. — 8. The pitted vessels show distinctly the
mercury in the areolae, as if in so many little pouches formed by thin
portions of the wall ; the same observations have been made in regard to the
reticulated vessels.

Aphyllostachys. — Professor H. It. Goeppert’s fine memoir on this singular
fossil plant, has been translated in the Journal of Botany for August. The
author makes it the text of a sermon on Darwinism. In the course of his
remarks he urges that no arguments in favour of the theory of Natural
Selection are to be found in the order in which plants present themselves
as regards their geological succession ; for it is known that the highest and
lowest algge existed at the same period. Herr Goeppert’s arguments
are not, however, quite conclusive : how, indeed, could they be so in the
brief space he allots for the discussion of a question which hangs on so
large a mass of botanical evidence P Plis observations on the character
of Aphyllostachys are much more important than his theoretical abstrac-
tions. He describes the specimen very minutely, and the plate which
accompanies the paper gives one a clear notion of the character of the
plant ; still he feels unable to decide on its affinities. He cannot find an
analogous form in either recent or extinct florae, and he now, after fifteen
years, is compelled to lay the matter before other botanists, in order that
they may settle it.

Botany at the British Museum. — The Annual Report shows that the officials
in the Botanical Department have certainly not been idle during the past
twelve months. The addition of specimens to the Museum amounts to
several thousands ; and of microscopic slides of Diatomacece no less than
5,000 have been purchased. In fact, the whole of the valuable collection of
the late Dr. Greville and the late Dr. Gregory are now to be seen in the
British Museum.

A new South African Senecio has been discovered by Mr. M'Owan, of
YOL. YI. — NO. XXY. K K

452

POPULAR SCIENCE REVIEW.

Grahamstown, and lias been identified by Dr. F. Mueller, of Melbourne.
The species is styled S. tropceolifolius. Dr. Mueller, in commenting on this
discovery, makes the following very interesting remarks on the geographi-
cal distribution of the genus : — Senecio is not merely more widely distributed
over the globe than any other existing genus, from the polar to the equinoctial
regions of both hemispheres (though almost absent in North Australia), but it
embraces more species than any other — nearly a thousand being on record, some,
however, but ill- defined. The genus almost as rich in species, and almost as
extensively diffused, is Solarium, and then seemingly follow Panicum , Carex,
and Euphorbia, though in Australia Acacia largely surpasses all others. The
species of Senecio , as representatives from almost every part of the globe,
become thus of the greatest possible interest, and are certain to be always
among the first which come under the notice of any photographical observer.
The Groundsels, though generally of the more humble forms of vegetation,
present, in a recently discovered species from the Chatham Islands ( Senecio
Huntii: “Vegetation of the Chatham Islands, sketched by F. M., p. 23,
plate 3) ; and in the Victorian and Tasmanian S. Bedfordii (F. M., Deport,
1868, p. 26), fair-sized trees, perhaps the only truly arborescent species of the
globe.

The Arctic Cladonice. — On this group of plants an essay, which we hope
to see printed in full, was read before the Botanical Society of Edinburgh,
by Dr. W. Lauder Lindsay. The Arctic regions include vast level, generally
treeless, barren tracts of country, whose vegetation is frequently exclusively
lichenose ; sometimes, indeed, consisting of a single species, the cosmopolite
Cladonia rangiferina. The author enumerates the different species and their
forms, belonging to the Cladonice, found in Arctic countries, and remarked
that, whether these may be regarded as consisting of many or few species,
their importance to man cannot be estimated by their mere numerical rela-
tions ; one species at least (C. rangiferina) is not only superior in economical
and even political importance to the better- known u Orchella-weed,” but it
is even on a footing with the valuable grains, timber trees, and other
phanerogams of more favoured regions. The author considered the econo-
mical value and applications of the Arctic Cladonice under the following
heads : — 1, as fodder or forage to animals, domesticated or wild ; 2, as an
ingredient of man’s food ; 3, as medicines, being used as tonics, astringents,
febrifuges, emetics ; 4, in the arts — e. g., perfumery and dyeing.

The Parasites of a Desmid. — Mr. W. Archer, who is one of our most
industrious students of microscopic Algae, records that he has found
Asteridia parasitic in the common Desmid, Penium digitus. In a collection
containing a number of the Penium digitus, Mr. Archer observed that a
considerable number of them showed “ some individuals one, the majority
two, and a few three, quite identical stellate bodies in the interior of each
cell.” These seemed to him evidently to have been formed at the expense
of the individual Penium in which they occurred. These stellate bodies Mr.
Archer identifies as the Asteridia. He lays down the following general
propositions in concluding his paper : — (1) The strictly parasitic nature of the
Asteridia seems probable, from the destruction of the Penium during their
formation ; (2) The observation is of interest as being the first record of the
occurrence of “ Asteridia ” in Desmids ; and (3) from their being of a form
and size not before noted in any of the Asteridia recorded.

SCIENTIFIC SUMMARY.

453

The Movement of the Oscillarice, according to the researches of Dr. Ferdi-
nand Cohn, depend on three facts : — 1st, a steady hut changeable rotation
around the long axis of the plant ; 2nd, the power of being able to push
itself variably backwards and forwards ; 3rd, the power of being able to
bend, to stretch, and to twist — in one word, its flexibility. — Vide Quarterly
Journal of Microscopical Science , July.

CHEMISTRY.

New Method of Organic Analysis. — Herr A. Mitscherlich describes a
new mode of organic analysis, which he states is applicable to all organic,
and many inorganic, compounds, and one of whose especial features is the
direct determination of the oxygen. Those who wish to pursue the method
must consult the original paper, the following being only a general account
of the process ; — Oxygen and hydrogen are determined together by heating
the substance in a current of chlorine, passing the products of combustion
over red-hot charcoal, and absorbing the chlorhydric acid, carbonic anhy-
dryde, and carbonic oxide formed by a saturated solution of plumbic nitrate,
a solution of potassic hydrate, and a solution of cuprous chloride in chlor-
hydric acid respectively. Chlorine, bromine, iodine, and sulphur, are deter-
mined simultaneously with carbon and nitrogen, by volatilising the substance
in a current of hydrogen, burning the mixed gases and vapours with oxygen,
removing the water by means of sulphuric acid, and collecting the products
of combustion in weighed vessels — with the exception of nitrogen, which is
measured. The products of combustion, besides the water, may consist of
carbonic anhydride, chlorhydric acid, bromine, iodine, sulphurous acid,
sulphuric acid, and traces of brom- and chlorhydric acid. A residue of
carbon also may be left in the combustion-tube. The water is absorbed by
sulphuric acid, the chlorhydric acid by plumbic nitrate, bromine by mercuric
oxide, iodine is weighed as such, sulphurous acid is absorbed by potassic
bichromate, carbonic anhydride by potassic hydrate, nitrogen is measured,
and the residual carbon weighed. — Yide Roggendorjfs Annalen, cxxx. 536.

A Syphon for the Laboratory. — It so often happens that in using the
ordinary syphon, acid and hurtful substances are introduced into the mouth,
that a new syphon, invented by M. Zaliwski Mikorski, will be gladly em-
ployed by chemists. The new syphon is not set at work by suction. One
of its legs is provided with an accessory tube, by blowing through which
the current becomes established.

Chemical Relations of Cafeic Acid. — At a late meeting of the Academy of
Sciences of Vienna, Herr Hlasivetz read a paper on this subject. He found
that by treating the acid with sodium-amalgam he produced a hydracid by
the addition of two atoms of hydrogen. This shows that there is an analog}’-
between cafeic acid and cinnamonic and coumaric acids. The three thus
belong to one series, each term of which possesses an atom of oxygen more
than the preceding one. Cafeic acid is isomeric with umbellic , eveminic , and
veratic acids.

Cheap Mode of obtaining Oxygen. — M. de Motay has suggested an econo-
mical method of producing oxygen, which is said to prove easy and efficient

k x 2

454

POPULAR SCIENCE REVIEW.

in practice. The substance used is manganate of soda, which M. de Motay
hopes to be able to sell to the trade at fourpence per kilogramme. Fifty
kilogrammes of manganate give, according to calculation, from 400 to 450
litres of oxygen per hour.

An Illustration of the Manufacture of Sulphuric Acid, which is very simple,
and may be found useful by lecturers as an experiment, has been described
by a correspondent of the Chemical Neivs. It is a modification of an experi-
ment described by Dr. Miller. Three tubes are passed through the cork
of a wide-mouthed bottle, the largest being connected by an india-rubber
junction with a pint funnel, and the small one to the left with a test-tube
generating NO by means of copper turnings and nitric acid. The middle
tube admits air. A little water is poured into the bottle first, to combine
with S03 for the production of H2S04. The funnel is covered in with a
metal cap, to which a small pan is suspended. This pan is a miniature
furnace. A bit of sulphur is placed in it and lighted. The fumes of S02
immediately flow down in a conspicuous stream into the bottle. Here they
encounter NO, and the usual reaction takes place. Any S02 which the
water may dissolve is expelled by boiling, when the solution answers to all
the tests for the presence of sulphuric acid. An extra cover, which slides
on the metal lid, conceals some air-holes, useful at the beginning of the
experiment.

The Estimation of Organic Matter in Water. — This is a subject of the
utmost importance, and it is much to be regretted that it has not received
the attention it deserves. At least we judge so from the fact that till
recently we have had no reliable method of distinguishing between the
organic matter present in water or ammonia and that present as excremen-
titious substance. It has lately been shown by Messrs. Wanklyn and
Chapman that the methods pursued by Drs. Frankland and Letheby hardly
compass this end. These chemists have therefore suggested the employment
of a new method of estimating organic matter. This method has been fully
described in their joint paper, read before the Chemical Society on the 20th
of June last; but the following account gives an idea of the nature of their
method : — Direct experiments were made upon known quantities of urea,
albumen, and gelatin dissolved in water, and the singular fact was disclosed
that, whilst the first of these bodies is completely changed into ammonia by
boiling with carbonate of soda, the two latter substances resist decomposition
until caustic soda (or potash) is introduced, when one-third of the nitrogen
contained in them is evolved in the form of ammonia. The remaining two-
thirds of this constituent are finally liberated in the same form upon adding
some crystals of the permanganate of potash and continuing the distillation.
The authors employ Nessler’s test for indicating the proportion of ammonia
originally contained as such in the water, as well as that subsequently
formed.

The Density of Ozone. — M. Soret, who sometime since stated the density of
ozone to be 1 1 times that of oxygen, now has given convincing proof of the
accuracy of his opinion. By causing the two bodies to u diffuse,” he has
found that the velocities of transmission give the same value for the density
of ozone as that already expressed, viz. times that of oxygen.

Detection of Bromine and Iodine in same Solution. — A paper has been pub-

SCIENTIFIC SUMMARY.

455

listed in the Comptes Rendus from the pen of Dr. T. L. Phipson, in which
the author points out what he considers to he a simple mode of ascertaining
the presence of bromine and iodine in the same solution. The method is
based on the fact that in the presence of sulphide of carbon and free chlo-
rine, iodides are first decomposed and afterwards the bromides, and further,
that the chlorine acts upon the iodine dissolved in the sulphide of carbon
to form quinti-chloride of iodine, which dissolves, and leaves the sulphide
of carbon colourless. If bromides be present, the sulphide of carbon as-
sumes an orange colour.

Chlorine and Manganese have been combined by M. Nicies in such pro-
portions as to form a deuto-chloride, which is, however, a less permanent
salt than the other haloid combination of this base.

The Impurities of the New (?) Ancesthetic. — In a paper read before the
British Medical Association at its meeting in August, Dr. Protheroe Smith
read a paper on Tetrachloride of Carbon, in which he gave the following
directions for the detection of its three impurities. These are as follow : —
1. Bisidphide of Carbon. — This is easily detected by evaporating over a
spirit-lamp a portion of the suspected fluid in a deep cup, when, if it
contains bisulphide, a slightly bluish flame will appear, whereas if free
from this impurity it would be entirely uninflamable. 2. Free Sulphur. —
Should such exist, after spontaneous evaporation of some of the tetrachloride
on a watch-glass, a fine opaque film will remain, which when heated would
give off the well-known fumes of sulphurous acid. 8. A peculiar sul-
phur-compound, which is discovered by dipping in the suspected fluid some
clean blotting-paper, which when dry will give a peculiar unpleasant smell
of dirty linen.

A New Cement — Oxychloride of Magnesium. — At a late meeting of the
Drench Academy, M. Dumas called attention to a new manufacture of M.
Sorel’s, a cement produced by combining chloride of magnesium with oxide
of magnesium, and possessing, as does the oxychloride of zinc, in a degree
incomparably greater than plaster of Paris, the property of not only taking
all variety of forms, but of solidifying and taking a high polish. Experi-
ments made two years ago leave no doubt as to the good quality of stones
prepared by this process, and the absolute resistance, of objects so fabricated
and moulded, to the deleterious action of water. u Industry and art will
therefore enter into possession of new elements of construction and trans-
formation. The chloride of magnesium that can be extracted from sea-
water, or which is found in great quantities solidified in interior seas as that
of Stassfurth, does not require to be entirely pure, and costs less than the
oxychloride of zinc.”

Estimation of Lime in Analysis. — At a meeting of the Drench Academy, M.
Boussingault communicated a new mode of finding the quantities of lime
in analysis. The process consists in precipitating the lime in the state of
sulphate, which is decomposed either by a Bunsen gas blowpipe, or by one
of Schlosing’s furnaces, the sulphuric acid being vaporised, and the lime
remaining pure. In several experiments on the decomposition of earthy or
metallic sulphates, M. Boussingault remarked frequent anomalies, the quan-
tity of the base remaining often being less than it ought to be. The fact is
not easy to account for.

456

POPULAR SCIENCE REVIEW.

Manager of the French Mint. — The post of Director of the Paris Mint,
vacant by the death of M. Pelouze, has been given to M. Dumas, the eminent
chemist. M. Dumas had previously resigned his appointment of professor in
the faculty of science of the University of Paris, and inspector-general of
the high schools of France.

Cause of the JDecolorisation of Iodine Starch. — In a paper, published in the
Bulletins de la Societe Chimique , M. Pellet states the following conclusions as
the results of his experiments in the cause of the deeolorisation of the
iodine starch, and the reappearance of colour on cooling : — 1. Deeolorisation
is caused by the solution of iodine starch in an excess of hot starch ; the solu-
bility being less in the cold, the colour reappears again on cooling. — 2.
Iodine starch is decomposed at 100°C,'aud iodine volatilises. — 3. Iodine
starch remains unchanged in alcohol, being equally insoluble in that liquor
whether hot or cold. — 4. Iodine starch may be regarded as a salt, which in
certain solvents is more readily soluble when hot, than when they are cold.

Silicates of Methyl. — In a recent number of Silliman’s American Journal ,
there appears the following account of the mode of preparing the above
compound. It was first attempted, by Messrs. Friedel and Crafts, to prepare
the silicate by reacting on methylic alcohol with chloride of silicium ; like
Ebelmen, they obtained a product impossible to purify, turning brown in the
air, and possessing a foetid odour. They noticed that this product always
contained chlorine. Wood-spirit was purified by treatment with chloride of
calcium ; the chloride of calcium compound decomposed with water, and the
alcohol rectified several times with sodium. The alcohol thus prepared was
sealed in a tube with silicate of ethyl, and the mixture heated during 20
hours at 210°C. After several fractional distillations, the principal product
isolated from the contents of the tube was a liquid boiling at 143° to 147°.
This liquid gave on analysis numbers which correspond with the composition
of a mixed silicate, diethylic, dimethylic, silicic ether. There being reason
to believe that a minute trace of water contained in the methylic alcohol
interfered with the success of the processes in which it was employed, this
alcohol was distilled twice with sodium, then with a small quantity of
anhydfous phosphoric acid. Thus prepared, it boils at 65*5°, has not the
disagreeable odour it usually has, smells like common alcohol, and does
not turn brown with soda. Methylic alcohol purified in this way, when
added to chloride of silicium, reacts like ordinary alcohol. When the
theoretical quantity of the alcohol has been added, the product is distilled,
and after a small number of fractional distillations two principal products
are obtained, one boiling at 120° to 122°, and the other at 201° to 202-5°.
The first is the normal silicate of methyl •, the second is the hexamethylic
disilicic ether. The normal silicate of methyl is a colourless liquid, has
rather an agreeable odour, is soluble in a considerable quantity of water.
Moisture or aqueous alcohol gives rise to condensed products, ultimately
silica. It burns with a white smoke composed of silica.

Crookesite , a Neio Thallium Mineral. — A mineral, rich in thallium, has been
discovered by M. Nordenskiold, in Mosander’s collection, and has been named
Crookesite, in compliment to Mr. W. Crookes, F.D.S., the discoverer of
thallium, and the accomplished editor of our contemporary the Chemical
News. Crookesite forms small, coherent, opaque masses, of metallic lustre,

SCIENTIFIC SUMMARY.

457

has a lead-grey colour, and sufficiently compact to admit of its ready separa-
tion from the grains of eukairite and the powder of berzelianite. I have
observed no trace of crystallisation in the mineral. In tenacity and hardness
it resembles chalkosine. Its specific gravity = 6-9. Before the blowpipe
crookesite fuses easily, forming a lustrous green-black enamel j the flame
is coloured intensely green. It is insoluble in hydrochloric acid, but nitric
acid dissolves it readily and completely.

Analysis showed it to contain

Copper ....

45-76

Thallium ....

17-25

Silver ....

3-71

Selenium ....

33-28

100-00

Street Bust a Poison. — The chemical analysis of W. Tichborne, of Dublin,

would* serve to show that street dust, which

we all take less or more into

our nostrils, may be the means of propagatin;

g various epidemic diseases. At

all events, the following results of analysis show that street-dust contains a

very large proportion of organic matter : —

Moist Dust from Grafton Street, Dublin, October 1866.

Moisture . . . . ,

. . 33-3

Organic matter . . ,

, . 25-1

Inorganic matter . . ,

. . 41-6

100-0

Street Dust, October

1866.

Soluble salts ...

. . 1-3 per cent.

Organic matter . .

. . 25-1 „

Soil from a well-made Poad upon which Sea-water had been used.

Soluble salts . . .

. . 7*5 per cent.

Organic matter . .

. . 21-1 „

Here it will be seen that the salts are about f the weight of the total
organic matters present. — Vide Chemical News, July.

The Calculus of Chemical Operations. — The important and philosophic views
which Sir Benjamin Brodie recently expressed on this subject have been
considered by "Dr. A. Crum Brown. In a paper by the latter, read before the
British Association at Dundee, the author stated that there were two points
which might be taken up for examination (1) The idea of a fractional
relation between chemical substances ; and (2) the manner in which Sir
B. Brodie had worked this out. He confined his remarks to the second, and
stated that his conclusion was that while the two s}rstems are equally con-
sistent, and may both be treated mathematicaly, Sir Benjamin’s was yet,
notwithstanding its elegance, simplicity, and consistency, to be rejected, on
the grounds that his fundamental hypothesis is wholly arbitrary, while

458

POPULAIi SCIENCE REVIEW.

change in this would involve considerable change in formulae, and further,
that the present formulae were quite convenient.

Atomic Weights of Cobalt and Nickel. — These have been investigated by
Winkler, who has determined them in the following manner : — The metals
were prepared in a state of perfect purity ; the cobalt, by reduction of re-
peatedly recrystallised purpureo-cobaltic chloride in a current of hydrogen at
a high temperature. The nickel, by adding to a solution of the commercial
carbonate in chlorhydric acid sodic hypochlorite, and treating the liquid in
this manner again so long as any cobalt could be detected in it ; the solution
was then purified from traces of copper and arsenic and precipitated with
sodic carbonate. The carbonate was converted into chloride, and sublimed
in a current of chlorine, and lastly reduced in a current of hydrogen.
Weighed quantities of the metals were then immersed in a perfectly neutral,
concentrated, cold solution of sodioauric chloride, and the weight of the pre-
cipitated gold determined. The mean of five experiments with cobalt gave
the number 29496. The mean of four with nickel, the number 29'527.

Blowpipe Reaction of Manganese and Chlorate of Potass. — In a recent
number of the Chemical News , it is stated that if chlorate of potash be
heated by means of a blowpipe, in a tube closed at one end till oxygen is
evolved, and then a trace of manganese added, the potash-salt will assume a
purple colour, owing to the production of permanganate of potash. This re-
action of manganese is quite as delicate as the one proposed by Berzelius.

How to test the Purity of Quinine. — In these days of pharmaceutical adul-
teration, a reliable test for the purity of a drug is of the utmost value. The
method, therefore, which M. Stoddart recommends for the detection of
quinidine when mixed with quinine, may be of interest to our readers. Six:
grammes of the suspected quinine are dissolved in a test-tube in 5 grammes
sulphuric acid, diluted with 3 grammes water; to this are added 7’5 grammes
ether, 18 grammes alcohol, and 2 grammes of a solution of sodic hydrate con-
taining about 8 per cent. The mixture is well shaken, and left to itself for
12 hours. If quinidine, cinchonine, or cinchonidine are present, they will be
found in a layer below the ether— quinidine as an oily liquid, cinchonidine
in crystals. The second method consists of a microscopic examination of the
crystalline precipitate produced in a saturated and neutral solution of
quininic sulphate by potassic sulphocyanide. — Vide Journal Pharm. iv. 50.

Death of Dr. Thomas Richardson. — The death of Dr. Richardson has been
so fully announced in the weekly and monthly journals, that we are only fol-
lowing a routine custom in reporting it. Few English chemists were better
or more favourably known to science than Dr. Richardson. He was Reader
in Chemistry at the University of Durham, as well as a Fellow of the Royal
Societies of London and Edinburgh, and member of the Royal Irish Academy.
He died somewhat suddenly, at Wigan, of congestion of the brain. Of late
years Dr. Richardson was best known to the chemical world by his work in
connection with u Richardson and Watts’s Chemical Technology.” Several
papers of his are to be found in the volumes of the Chemical News and
Chemical Gazette.

Neiv Method of Qualitative Analysis. — A method in which neither sul-
phuretted hydrogen nor ammonic sulphide is employed, has been suggested
in Poggendorff s Annalen (cxxx. 324) by Herr E. Zetnow. The following are

SCIENTIFIC SUMMARY.

459

the reagents employed, and the substances they help to throw down and
separate from an aqueous solution : — 1. Chlorhydric acid precipitates lead,
mercury, and silver. — 2. Sulphuric acid precipitates lead, barium, strontium,
and calcium. — 3. Baric hydrate sets free ammonia ; the filtrate is used for
the detection of sodium and potassium. — 4. Zinc is added to the filtrate-
from 2, the hydrogen ignited and tested for antimony and arsenic ; antimony,
arsenic, tin, mercury, copper, cadmium, and bismuth are precipitated. — 5.
Baric carbonate precipitates, from the filtrate of 4, iron, chromium, and
aluminium. — 6. Ammonic carbonate, after removal of the baryta, precipi-
tates, from the filtrate of 5, manganese and calcium ; the filtrate is tested for
magnesium, cobalt, and nickel. — 7. Zinc is tested for in the original solution.

GEOLOGY AND PALAEONTOLOGY.

The Osteology of the Mesotherium forms the subject of a fine series of
memoirs presented to the French Academy by M. Serres. In the first com-
munication, he treats of the structure and relation of the several parts
composing the vertebral column, and supplies tables in which are recorded
the exact measurements of the various bones examined. The atlas axis,
fifth dorsal, eighth lumbar, and fourth cocygeal vertebrae have been
especially dwelt on by the author. M. Serre3 remarks that, in determining
the true osteogenical relations of the parts of the skeleton, it is necessary to
study the bones in their foetal state. This is, of course, impossible in the
case of fossil skeletons. He suggests, therefore, that the palaeontologist
should examine the state of solidification and the density of the different
parts of the compound bones. This, he says, will give a clue to their
developmental relations. This rule applied to the Mesotherium shows that
in the development of its spinal column, the laminae, as in all mammalia,
were the first to ossify ; the ossification of the centres took place subse-
quently.— Yide Comptes Rendus, July and August.

The Volcanic Disturbances at Santorin. — A letter published in a late number
of L’lnstitut reports that the disturbances of the Santorin group of islands
continue. New portions of the sea-bottom have been elevated, and some of
them have appeared above water. The raised portions are within four or
five metres of Micra-Kammeni. Formerly the channel was twenty-one
inches deep, but it is now not more than three. The island of Aphroessa
remains stationary, but Yattia is now divided into two islands. Around
the newly-formed lands the sea is of a yellowish-green colour, and has
a temperature varying, according to the locality, from 25° to 75° centigrade.
M. Cigalla, who has studied the volcanic phenomena very carefully, thinks
another great eruption will soon occur, and that a true volcanic crater will
be formed at the top of the George island.

The Magnetic Needle in the study of Volcanic Districts. — A theory of some
novelty, and which appears to have been put to a practical test, has been
started by M. Jansenn, who has been exploring the Santorin region. This
eminent physicist alleges that the magnetic needle may be employed to detect
disturbances which take place at such a depth that they are not recognisable

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POPULAR SCIENCE REVIEW.

by the ordinary methods. With regard to his experiments in Santorin, he
says that the observations made show that there is a very powerful magnetic
influence in the direction of the volcanic lines already mapped out by M.
Fouque, and indicated by the eruptive centres Micra , Georges , and Aphro-
essa. He found the magnetic needle dip very much less in those parts beyond
the volcanic region than in others. M. Fouque’s study of the district in the
neighbourhood of Aphroessa led him to suspect the existence of a secondary
fissure. M. Jansenn has brought his magnetic tests to bear on this question,
and he has found that the magnetic records tend very strongly to bear out
M. Fouque’s suspicion. M. Jansenn recommends Government to insist on
general magnetic observations during surveys, &c., as he says they afford us
a means of sounding the depths of solid strata, and possibly of anticipating
earthquakes.

Fossil Foraminifera of Austria. — At one of the late sittings of the Im-
perial Academy of Vienna, Herr Reus presented his treatise on the Fora-
miniferous Faunae of the country. He recorded several new species, most of
which are referred to the family Miliolidse.

Spectroscopic Examination of the Flames of Stromboli. — This curious inves-
tigation has been conducted by M. Jansenn, who has made known his results
in a letter to M. Saint-Claire Deville. There was considerable difficulty in
conducting the observations, owing to the quantity of fine powdery matter
thrown up with the flame. But M. Jansenn was able to demonstrate the
presence of sodium in large quantity, and of copper, chlorine, and carbon in
lesser proportions. The flame, as usually occurs in such cases, resulted from
hydrogen.

The Amazon Valley. — Professor Agassiz has written a letter to M. Elie de
Beaumont, describing the geological character of the Amazon Valley. He
states that the valley consists of a species of mud, of which portions are
extremely hard ; it extends from Para to Peru, and appears to rest on a
cretaceous deposit. The river has cut its bed through the mud, and this
latter has, in some instances, a depth of nearly a thousand feet.

The Fossil Plants of Wolfgang have been described by Herr Unger in a
communication to the Vienna Academy. The species belong to the lower
cretaceous beds.

The Pone-caves of Belgium. — In a la'te number of the Bulletin of the
Royal Academy of Brussels, a note appears from M. Dupont, in which this
geologist states that he has been examining a new bone-cavern known as
the Trou-madame. In the stratified mud he found a series of human bones,
remains of pottery, bones of deer, and other animals. The human remains
include a perfect skull and lower maxilla.

Photographs of the Sierra Nevada. — A set of photographs of this moun-
tain-chain has been sent to Paris by a geologist of California. They exhibit
various marks of striation resembling those of the Alps. These are found
to occur at a height of 3,000 metres above the sea-level.

Volcanic Eruptions near Portugal. — M. Deville has called attention to a
statement which recently appeared in a Portuguese journal, announcing
that Tersira and Graciosa, two islands near Lisbon, have been subjected
to continual volcanic eruptions •, very strong shocks of earthquakes have
been felt, and have produced many islets, one after the other, analogous

SCIENTIFIC SUMMARY.

461

to those of Santorin, in Greece. On the 1st June a submarine volcano
cast up igneous matters in such quantity, that a tongue of land has been
formed with the continent. This ground is as yet unapproachable, on account
of the incandescence of the rocks, as well as the sulphurous vapours from
the fissures. M. Deville asked that the Academy should take an interest
in these new eruptions, as it did in those of Santorin. — Vide Comptes
Bendus , July 1.

A Burning Well. — While some artisans were engaged in making borings
for an artesian well at Narbonne, the water rushed forth with great vio-
lence, and soon burst into flame. The flame, which arises from the combus-
tion of carburetted hydrogen, is reddish and smoky, and does not emit a
smell either of bitumen or sulphuretted hydrogen. The u sinking ” for the
spring was made on the left branch of the Aude, in a plain situate about
two metres above the sea-level, and composed of alluvial mud. The
alluvial mud extends to a depth of six metres ; then follow tertiary lime-
stones and marls, with the remains of marine shells. At the depth of 70
metres, the spring containing the inflammable gas was met with.

The Plant-beds of North Greenland. — From the report made by the Sec-
retary of the Committee on this subject to the British Association at its
recent meeting, it would seem that nothing has as yet been published on
the points investigated. Mr. Whymper started from Copenhagen on the
20th of April, but no intelligence has since been received from him.

The Leaf -beds of Hampshire. — The report on this subject was presented
to the British Association by Mr. W. Stephen Mitchell, who pointed out
that there was a better chance of determining the remains from these beds
than those from many others. He laid stress on the fact that we know the
age of the beds from stratigraphical evidence not depending on botanical
testimony.

The Internal Heat of the Earth forms the subject of a memoir by Dr. J.
Schwarez, who arrives at the following conclusions : — The different corol-
laries of the central-fire doctrine were not adequate to explain the different
groups of natural phenomena, for the sake of which these corollaries were
deemed essential fifty years ago. The whole system of the central-fire
doctrine, the alleged dubious moment of the increase of underground tem-
perature alone excepted, was bound up merely by artificial ties j and as soon
as the question of the supposed increase of underground temperature will
be, by direct empirical argument, decided in the negative, then the ruin of
the whole central-fire system would be inevitable. The memoir concludes
with some suggestions as to how experiments should be made in order to
ascertain the temperature of the earth, at different depths, simultaneously in
different quarters of the globe. — British Association : Dundee Meeting.

Palceozoic Insects of Nova Scotia. — Professor Dawson, of McGill’s
College, Montreal, has a paper in the Geological Magazine, in which he
describes some interesting insect-remains from the palaeozoic rocks of Nova
Scotia. In the Nova-Scotian coalfields insects have not hitherto been
discovered, except in some fragments found by the author some time since.
Last year, however, a very beautiful wing was found by Mr. J. Barnes, of
Halifax, in a bed of shale at Cape Breton. This specimen has been ex-
amined by Mr. S. Scudder, of Boston, who pronounces it to be a member

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POPULAR SCIENCE REVIEW

of the Ephemeridse, and gives it the name of Haplophlebium Barnesii in
compliment to its discoverer. It must have belonged to an insect measuring
at least seven inches across the wing. Commenting on the conditions under
which it lived, Dr. Dawson says : u When we consider that the larvae of such
creatures inhabit the water, and delight in muddy bottoms rich in vegetable
matter, we can easily understand that the swamps and creeks of Carbonife-
rous Acadia, with its probable mild and equable climate, must have been
especially favourable to such creatures ; and we can imagine the larvae of these
gigantic Ephemeras swarming on the deep black mud of the ponds in
these swamps, and furnishing a great part of the food of the fishes inhabit-
ing them ; while the perfect insects, emerging from the waters to enjoy
their brief space of aerial life, would flit in millions over the quiet pools
and through the dense thickets of the coal-swamps.” — Vide Geological Maga-
zine, September.

Zone of Ammonites Transversarius. — A paper on this subject, by the late
Dr. Oppel, has been communicated to the Imperial Geological Institute of
Vienna. This zone of the Tipper Jurassic series is limited above by the zone of
Terebratula impressa. It may be traced from South-west Poland, through
the Carpathians, Moravia, Bavaria, the Schwiibische Alps, the Swiss Jura,
the Alps, France, and Spain, as far as Algeria. The number of fossil species
known to occur in it amount to 217 ; among them are microscopic remains
of Crustacea and Radiata, and many new species af Foraminifera.

Hungarian Fossil Mammals. — Herr Hantken records the discovery of the
following remains from the Post-pliocene deposits of Fiinfkinchen: — Ur sics
spelceus , many fragments of lower jaws, loose teeth, and vertebrae ; Hycena
spelcea , Goldf., a fragment of a jaw belonging to a young animal, with the
first teeth and protruding canines ; Fquus fossilis , Cuv., a fragment of a
lower jaw with a tooth ; JBos priscus, Boj., a second collar vertebra; Rhino-
ceros tichorhinus , Cuv., a single tooth.

The /Sulphur Springs of Formosa. — At the last meeting of the Geological
Society, Mr. C. Collingwood, M.B., presented a paper on the sulphur-springs
of Northern Formosa. These springs are situated amongst the hills near
Tamsuy, in the north-eastern corner of the island of Formosa, and indicate
the existence of volcanic action near the surface of the region — a phenomenon
otherwise afforded by the frequent occurrence there of earthquakes. One
spring possessed the character of a mountain-torrent, and had a temperature
of about 130°. The spot containing most of the springs occupies about two
acres of ground, is quite barren of vegetation, and is covered with low
hillocks of friable rocks and debris, interspersed with shallow pits containing
mud, sand, and sometimes water. From cracks and fissures in these depres-
sions arose clouds of steam ; and around them was strewn a quantity of
sublimated sulphur, the yellow colour of which was visible from a distance.

Shells in the Ruins of Pompeii. — Among the objects to be seen at the Museo
Borbonico at Naples, is a collection of shells taken from some of the ruined
houses of Pompeii. These shells have been carefully examined by Mr. R.
Damon, who states that they are all those of recent species. He further
remarks that some of them are shells only found in Eastern seas, the Indian
Ocean, &c. Hence he thinks it not unlikely that they formed part of a
Pompeian Museum, and he asks, u Did the original proprietor form one of a

SCIENTIFIC SUMMARY.

463

Natural History Society, of which the distinguished naturalist Pliny, who
perished at Pompeii, was a member P ” — Yide Geological Magazine , July.

A Hycena Den in Carmarthenshire has been described by Dr. Henry Hicks.
The cavern is known as the Crygan Cave, and is near Langharne. The bones
found by Dr. Hicks were those of Hycena speloea, Rhinoceros tichorhinus,
Elephas primigenius , Equus, and Cervus. It is remarkable that most of the
bones are gnawed exactly in the same manner as those from Wookey Hole.

Coalfields in St. Catherines , Brazil. — Mr. Edward Thornton has transmitted
to London a communication on this subject. The existence of coal in this
district has for many years been an established fact ; but no practical ex-
ploration had been made until the years 1861-63, when Viscount Barbacena,
having purchased a tract of land containing the best seams, ascertained the
existence of a series of coal-beds at nine different levels, underlying a sand-
stone formation, horizontally disposed, and varying in thickness from 1£ to
10 feet. Analyses of specimens of the coal prove it to be of good quality,
its profitable working depending solely upon the facilities for transport. —
Geological Society , June 19.

Cretaceous Flora of Belgium. — Mr. E. Coemans has published an essay on
the fossil flora of the first stage of the cretaceous strata of Hainault. The
plants consist almost exclusively of Conferee and Cycadece.

Banded and Brecciated Concretions. — Mr. John Buskin, who has returned to
the field of geology, has given us, in the Geological Magazine , a most in-
teresting paper on the origin of the above forms of concretionary growth.
The illustration which accompanies the paper is also most instructive. Mr.
Buskin thinks that the transformations of solid into fragmentary rocks may
be ranged under the following heads : — 1. Division into fragments by con-
traction or expansion, and filling of the intervals with a secreted, injected,
or infused paste, the degree of change in the relative position of the frag-
ments depending both on their own rate and degree of division, and on the
manner of the introduction of the cement. — 2. Division into fragments by
violence, with subsequent injection or secretion of cement. The walls of
most veins supply notable instances of such action, modified by the influence
of pure contraction or expansion. — 3. Homogeneous segregation, as in oolite
and pisolite. — 4. Segregation of distinct substances from a homogeneous
paste, as of chert out of calcareous beds. My impression is that many so-
called siliceous a breccias ” are segregations of knotted silex from a semi-
siliceous paste ; and many so-called brecciated marbles are segregations of
proportioned mixtures of iron, alumina, and lime, from an impure , calcareous
paste. — 5. Segregation, accompanied by crystalline action, passing into
granitic and porphyritic formations. — Geological Magazine , August.

Relations of the Upper and Lower Silurians. — This difficult problem has
been solved by Mr. T. Mc’K. Hughes, who, from a very large practical know-
ledge, arrives at the conclusion long since (1846) stated by Sedgwick — viz.,
that “ on the evidence both of mineral structure and of fossils, we are com-
pelled to separate the coniston flags from the coniston limestone and calcareous
slates, placing the former at the base of the Upper Silurian series of the lake
district.”

Becidiar Stratum in Arbroath Cemete)'y. — In the Geological Section of the
British Association, Mr. Carruthers called attention to specimens of a

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POPULAR SCIENCE REVIEW.

ferruginous layer, common in several districts in Scotland, which he had
obtained from the new cemetery at Arbroath. It was a thin compact layer,
following the surface of the ground, independent of the nature of the soil,
and forming a serious barrier to cultivation. It had never been noticed in
systematic works, and, as far as Mr. Carruthers knew, no satisfactory expla-
nation had been given of its origin.

Ancient Glacier in the Pyrenees. — M. Chas. Martens, who was present
at the meeting of the British Association, read a paper on the ancient
glacier of the Valley of Argelez. This glacier and its affluents descended
from the crest of the Pyrenees, whose summits now reach an altitude varying
from 6,000 to 9,000 feet. The roots of the glacier were in the cirques of
Gavarnie, Troumouse, Pragneres, &c., and the glacier extended into the
plain as far as the villages of Peyrouse, Loubajac, Ade, Juloz, and Arcisac-
les- Angles. Along the valley, polished and striated rocks, scratched pebbles,
glacial mud, moraines, and erratic boulders, are the proofs of its existence.
At Argelez the thickness of the glacier was about 2,100 feet, and, at the
opening of the valley at the foot of the Pic de Geer, near Lourdes, 1,290
feet. Between Lourdes and the village of Ade, the railway runs across
seven moraines ; and the railway from Lourdes to Pau is cut, as far as the
village of Peyrouse, through glacial deposits. The Lake of Lourdes is a
glacial lake, barred by a moraine, and surrounded by numerous erratic
boulders proceeding from the high Pyrenean mountains. Some of the
boulders are of large dimensions : thus one of them, between the lake and
the village of Poueyferre, is thirty feet in length, twenty-three feet in width,
and eleven feet in height. This lake of Lourdes, surrounded by hills covered
with briars, reminds one in many respects of the small lakes of Scotland.

MECHANICAL SCIENCE.

Water Supply of London. — Mr. Ormsby, C.E., has proposed a plan for
obtaining the water-supply of London, perhaps more remarkable for its
originality than for its practicability. Starting from the idea that all water
which has passed through strata of earth is more or less contaminated, ®Mr.
Ormsby proposes to construct non-absorbent receiving beds, by which' the
entire rainfall will be collected in the same condition of purity as when it
reaches the earth. “ The arrangement of the collecting surfaces may be
illustrated by a chess-board, where each square would represent a collecting
basin, the centre of which would be two feet lower than the sides. The
lines between those squares would represent walls 12 inches thick, 'built
about 2 feet high, and filled in behind with earth to such a height as to
admit a bed of concrete being laid upon it, so that its upper surface may slope
from the edge of the wall to the centre of the basin. Upon this bed of concrete,
Bangor or other equally good and durable slates are proposed to be laid, set
in cement ; and when this is done, the waterworks are completed, so'that the
jsntire rainfall will immediately flow off into the central pipe or chamber
which communicates with the receiving reservoir.” Thus, in place of being-
driven to the sources of the Severn or Thames, or to the lakes of Westmore-
land, for his supply of water, Mr. Ormsby would erect his collectingNbeds

SCIENTIFIC SUMMARY.

465

anywhere in the neighbourhood of London, where the atmosphere is suffi-
ciently pure, and obtain his water direct and uncontaminated from the
clouds.

Dynamical Transmission of Power. — Of all the recent mechanical inven-
tions exhibited at Paris, probably none is destined to more important appli-
cations, or has required a greater amount of practical skill in its development,
than the system for the transmission of motive power to great distances, by
means of bands of endless wire rope, exhibited by M. Hiru. The single
novelty of principle, if such it can be termed, is the substitution of velocity
for weight in the rope ; but the devices by which the system is carried out,
so a3 to obviate losses of power on the one hand, and injurious wear on the
other, are of the highest merit. For transmitting 120 h.p., M. Hiru adopts
a rope only 0*4 inches diameter, passing over pulleys 13 or 14 feet diameter,
and making 100 revolutions per minute. With these proportions, inter-
mediate supports are not required for less distances than 160 yards. He
estimates the loss of power in transmitting 120 h.p. a distance of 12 miles
at only 21 h.p. The system has received considerable development in
France, having been applied already in 400 instances. An interesting account
of the invention will be found in Engineering for June 14.

Rifled Small Arms. — The Government have now experimented upon up-
wards of 80 breech-loading rifles, sent in for competition with the Snider
gun. In the trials for rapidity of fire, the time required to discharge at a
target 12 rounds of ammunition varied from 39 seconds (Soper rifle, with
Boxer cartridge) to 123 seconds.

Gunpowder Magazines. — In reply to the Commission, appointed by Govern-
ment after the Erith explosion in 1864, to report on the measures which
ought to be taken for the safe storage of gunpowder in magazines, Mr. Mallet
has written a most interesting letter on the effects of the explosion of large
masses of gunpowder, and on the laws of the propagation of the aerial and
earth waves which carry destruction to neighbouring objects. The letter
will be found in the Engineer of June 14. Mr. Mallet does not think that
great destruction is likely to be caused by the elastic wave of shock propa-
gated through the earth, except within a very limited area round the focus.
To protect the surrounding country from the effects of the aerial wave, he
suggests the construction of a large permanent traverse or bank, in the
shadow of which surrounding objects would be secure from the direct action
of the aerial wave. In order that this traverse may stand, it must be with-
out the sphere of explosion, within which the effect of the explosion is to
form a paraboloidal crater in the earth on whose surface it is exploded. The
inner slope should have an inclination fixed by the asymptotes of the curve
representing the section of the excavated crater. In fact, the magazine should
stand in the centre of a conic frustum, or etonnoir.

Hot Air Engine. — An interesting and novel form of air-engine, exhibited
by Mr. Shaw at Paris, has been experimented upon with the following
results : —

Duration of experiment, 7 hours.

Average work (indicated), 22 h.p.

Total fuel used (deducting 20 lbs. remaining unburnt, and 18 lbs. wood
for lighting), 222 lbs.

Average quantity of fuel per h.p. per hour, l#41bs.

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POPULAR SCIENCE REVIEW.

It will "be seen, that, so far as economy of fuel is concerned, this engine
■attains an efficiency hardly ever reached in a heat-engine, ordinary steam-
engines requiring 4|- bs. of coal per h.p. per hour, and the best marine
engines 2| lbs. The common vice of air-engines, of inefficiency in the trans-
mission of heat from the furnace to the air, Mr. Shaw obviates by passing
the whole of the products of combustion through the cylinder ; and to this,
doubtless, is to be attributed much of the efficiency of this engine. It re-
mains to be seen whether the practical difficulties which beset the use of air
at a high temperature have been overcome. The engine has been working
for two months in the Exhibition, apparently without any irremediable
•defect. Professor Pankin e has contributed to the pages of the Engineer a
mathematical investigation of the action of engines of this kind.

Solid and Laminated Armour Plates. — We have from time to time noticed
those results of the experiments against armour-plates which can more
strictly be considered as new scientific facts ; we may, therefore, mention
that recent experiments have given a distinct measure of the relative resist-
ance of solid armour as used universally in this country, and the laminated
armour, or armour of superposed plates, generally adopted in America. In
the earlier English experiments with cast-iron Armstrong shot, the laminated
armour proved to be most materially weaker than solid armour, but in the
recent experiments with chilled iron Paliiser shot with ogival formed heads,
the difference, although still marked, is not so great. Three 7-inch targets
were erected, one consisting of a solid plate, another of two 3^-inch plates,
the third of three 2^-inch plates. With the 7-inch gun and Paliiser shot, a
charge of 15 \ lbs. was required to penetrate the solid plate ; 14 lbs. to pene-
trate the target of two plates ; and 13 lbs. to penetrate the target of three
plates. The work done in each case is proportional to the charge.

Strength of Iron and Steel, when subject to Vibration and repeated Changes o f
Load. — M. Wohler has made some important experiments on this subject,
some of the results of which, with diagrams of the apparatus employed, may
be found in Engineering , August 23. When bars were placed so as to be
strained alternately by tension and compression, as is the case with axles,
the iron bars broke ultimately with 8 to 9 tons per square inch, and the steel
bars with 12 to 15 tons. When the repeated strains were in one direction
only, the iron required 15 to 18 tons, and the steel 22^ to 25 tons tension.
These bars were strained transversely. Bars subjected to simple tension gave
similar results.

Mont Cenis Railway. — This railway, to which reference has already been
made in these notes, is now nearly complete, the first engine and train
having successfully made the passage from St. Michel to Susa, crossing the
mountain barrier between France and Italy at an elevation of 6,700 feet above
the sea.

MEDICAL SCIENCE.

Muscular Contraction studied under the Microscope. — The myograph which
M. Marey employed in investigating the nature of muscular contraction is
said by M. Eouget to give very unsatisfactory results. The opinion which

SCIENTIFIC SUMMARY.

467

M. Rouget expresses is that muscular contraction does not consist of a series
of successive shocks or vibrations. On the contrary, he says, the muscles
of living animals in a state of sustained contraction, appear perfectly motion-
less when examined by the microscope. The undulations traced by the
myograph exist, according to M. Rouget, only during the period of variable
contraction, when the exciting influence has not displayed sufficient in-
tensity to call the muscle into complete contraction. When, for example,
a powerful electric current is substituted for a weak one, the vibrations,
before evident, entirely disapear, the muscle remaining in a perfectly rigid
state.

The Relation of Cow-pox to Small-pox. — The report which M. Danet
presented to the Trench Academy of Medicine contains the following
conclusions: — 1. Cow-pox and small-pox are two distinct maladies.
2. Cow-pox does not predispose the patient to any affection. 3. There
is no relation between typhoid fever and small-pox. 4. The vaccine

matter after a time loses its anti-variolic properties. 5. The vaccine
matter is a better preventative of small-pox than the variolous matter.
6. Vaccine matter should be renewed. 7. Predisposition to small-pox is
greater among the young and aged than among the middle-aged. 8. Re-
vaccination is essential. 9. Even those who have had small-pox should be
vaccinated. 10. In passing through the organism, the vaccine matter
borrows certain of the matters from the constitution ; vaccination, therefore,
from arm to arm may be objectionable. 11. The febrile state is unfavourable
to the satisfactory action of the vaccine matter. — Vide I? Institute July 3.

Secondary Electro-motive Rower of Nerves. — The memoir which Signor
Matteucci has published is likely to throw light on some of the obscure
phenomena of secretion. The Italian physiologist finds that this secondary
force is far more powerful, and exerts a more decided influence, in chemico-
vital operations than is generally believed.

Section of the Pneumoyastric Nerves. — In a paper read before the Societe
Philomathique of Paris, M. Vulpian has shown that unless both nerves are
divided at the same time the consequence is not fatal. He states that no
danger follows section of the pneumogastric nerves when an interval of a
few weeks is allowed to elapse between the section of the right nerve and
that of the left one. He reports the following experiment : — On October 5,
1865, I divided the right pneumogastric nerve of a dog in the middle of the
neck, and then brought the two ends together with a suture. On March 15,
1866, 1 performed a similar operation on the left nerve. The results of the
operation were vomiting for about a fortnight, and restoration to health in
a month after the operation. — Report of Meeting of Societe Philomathique ,
August 3.

A New Theory of Tuberculosis. — M. Lebert has just stated the singular
hypothesis that tuberculosis is caused by a constriction of the pulmonary
artery.

Experiments on Inflammation of the Liver. — The experiment of Herr
Holme is an erroneous one. He draws a silk thread through a living
animal’s liver. After a few days he removes it, and examines the cells
adherent to and entangled in its filaments. From the results obtained by
microscopic examination of these he comes to the conclusion that, in the liver,
YOL. YI. — NO. XXY. L L

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POPULAR SCIENCE REVIEW.

inflammation makes most progress along the line of hepatic cells, and is less
or more impeded by the connecting tissue. — Vide L'Institut, August 28.

Experiments on Inflammation of the Trachea. — M. W. Reitz, of St. Peters-
burg, has published a paper on the croup-like inflammation of the trachea
(windpipe) produced artificially. The experiments made by the author are
of interest. The membrane was irritated artificially, and the inflammation
followed the irritation in about half an hour. The first effect was the
production of a series of new cells, which, according to the author, were
evidently derived from the epithelium of the trachea. Subsequently there
occurred coagulation of fibrine in the interstices of these cells. Thus there
was formed a network of delicate filaments, whose meshes contained cells.
These cells, when separated by means of needles, and examined under the
microscope, were found to be simple spherical bodies unprolonged into
filaments, as is sometimes seen. It was found that at a later period the
tracheal rings became also more or less affected.

Poisonous Action of Bromide of Potassium. — The experiments of MM.
Eulenberg and Guttman show that the action of bromide of potassium is
upcn the heart, which, in larger doses, it paralyses. These physiologists
injected a solution of the bromide, containing 2 to 4 grammes (from 30 to
40 grains troy) beneath the skin of dogs, and found it produce considerable
disturbance of the heart, together with diminution of sensibility, and of
the power of voluntary movement. Death followed in from ten to forty
minutes, being caused invariably by paralysis of the heart. This result was
confirmed by a large number of experiments on frogs and other animals.

Liebig' s Food for Infants. — The statement made to the French Academy
some weeks since concerning Baron Liebig’s soup for children was likely to
injure the reputation of this excellent form of artificial diet. M. Depaul
alleged that four children, fed from their birth with Liebig’s food, had all
died from its effects. The Academy, having communicated with Baron
Liebig, received the explanation of the deaths. The food had been improperly
prepared. As the preparation is, therefore, one of importance, we are glad
to see that all the difficulties and possible errors are fully gone into in a
recent paper by Herr Pfeuffer. This paper is styled Liebig's iSuppe fur
Sauglinge , and is published in Aerztliches Intelligenz-Blatt , No. 31.

Foes Mercury produce Increased Secretion of Bile? — This was the question
asked, but not answered, by a committee formed last winter in Edinburgh.
The committee was composed of Professors Christison and Maclagan, of the
Edinburgh University ; Dr. Rogers, formerly of St. Petersburg ; Drs.
Rutherford, Gamgee, and Erazer, assistants in the Edinburgh University;
and Professor Bennett, the Chairman and Reporter. After studying all that
had been previously published *by authors (an account of which was fur-
nished by Dr. Rogers), the Committee proceeded to make further experi-
ments on dogs, the animals which had been found best fitted for the purpose.
These experiments were carefully conducted by Drs. Rutherford and Gamgee,
occasionally assisted by Dr. Erazer, and superintended by the Committee.
Professor Bennett gave the results of four series of experiments as to the
amount of bile secreted, with and without mercury. In each case the
weight of the animal was ascertained, a tertiary fistula formed, the amount
of food ascertained and analysed, and the secretion of bile for twenty-four

SCIENTIFIC SUMMARY.

469

hours measured, and its solids and salts ascertained. Tables were exhibited
in which the results arrived at were estimated in relation to each kilogramme
of dung and of food. The greatest variations were found to exist in the
amount of bile secreted daily, independently of the amount of food or other
obvious cause. The same fact was observed when mercury was given. No
conclusions, however, were drawn, as further researches were required before
so intricate and difficult a subject could be sufficiently investigated. — Vide
Report presented to British Association.

Influence of Heat on Muscular Contraction. — A very valuable paper has
been laid before the French Academy by M. Chmoutevitch, in which the
author shows that heat has a greater effect on the determination of muscular
contraction than is generally supposed. M. Chmoutevitch conducted his
experiments on the gastroenemius of the frog, and has arrived at these con-
clusions : — 1. The mechanical power of the muscle increases up to 30° to 33°
(Centigrade P), according to its length and tension. 2. If the temperature
be raised above 33°, the power of the muscle diminishes, until, as the tempe-
rature becomes higher, a point is arrived at which may be called the zero of
work. 3. In experimenting with two muscles which, in all but temperature,
are under like conditions, it is found that the one Submitted to the higher
temperature loses its power of contraction more rapidly than the other. 4.
The total work of a muscle (represented by the weight it can sustain) is
always greater at a low than at a high temperature. 5. The explanation of
the increase of mechanical work during the elevation of temperature is found
in this fact, that the elasticity of the muscle increases with the temperature.

Is there Animal Electricity ?■ — M. Schultz-Schultzenstein answers, there
is not. According to this savant, the researches of Matteucci, Dubois,
Reymond, Remak, Radcliffe, and others are valueless, and arose out of a
blunder (!). M. Schultzenstein believes that the electric indications which
have been attributed by physiologists to the vital action of the tissues, are
simply the consequence of the salt and water used in their experiments. He
is somewhat dogmatic in the expression of his opinions, and among other
startling statements occurs the assertion that a Velectricite animate est une
illusion .” He lays down the following conclusions : — 1. The supposition that
living muscle produces electricity is incorrect. If needles be plunged into
the foot of a living animal and be placed in communication with the galvano-
meter no deflection of the needle occurs. — 2. Muscles removed from the body
give evidence of electricity, but this is because of the combination of the
decomposing tissue with the oxygen of the air. — 3. Salt water causes the
galvanometer needle to be very decidedly deflected. This explains why meat
like pork which is salted gives evidence of electricity. — 4. The supposed
electric current in the human muscle is solely caused by the salt water in
contact with the tissue. — 5. In diseased structures the electric current is
derived from the decomposing tissues. — 6. The electricity of the secretions
is similarly produced. — Vide Comptes Rendus , August 26.

A Photo-sphymograph. — At the meeting of the French Academy, on the
19th of August, M. Ozanam gave a description of a new contrivance, some-
what like that employed in an observatory, for registering the movements of
the pulse. It is a modification of M. Masey’s Sphymograph, a tube of mer-
cury being substituted for the indicator. The pulsations being communicated

L L 2

470

POPULAR SCIENCE REVIEW.

to the column of mercury, the elevation and depression of this latter throw
shadows on a revolving sheet of photographic paper and are thus re-
corded.

The Coagulation of the Blood. — With a degree of moral courage which
we fear few of our savants would venture to show, Dr. Richardson has with-
drawn his theory of the coagulation of the "blood. At the meeting of the
British Association he announced that recent research showed the ammonia
hypothesis to be no longer tenable, and he therefore begged to withdraw it.
Experiments which he had lately made on the influence of extremes of heat
and cold on albuminous and fibrinous fluids, have shown to him that the
process of coagulation in these fluids is due to a communication of caloric
force to them, and to a physical or molecular change, determined by the
condition of their constituent water. Thus all substances which possess the
power of holding blood in the fluid condition, through fixed alkalies, various
soluble salts, and volatile alkali, in every respect act after the manner of cold.
They render latent so much heat, and in the absence of that heat the fibrine
remains fluid. In the opposite sense, every substance which combines with
water and produces condensation, with liberation of heat, quickens coagula-
tion. The direct effects of heat and cold illustrate the same truth, and
upon these facts turn the differences of coagulation in animals of different
temperatures. Those of our philosophers who work for reputation alone
(not a few), may think a recantation like that of Dr. Richardson’s rather a
perilous proceeding. To some small minds it may seem so. We venture to
believe, however, that the step Dr. Richardson has taken redounds in the
highest manner to his credit, and we believe that it will only add another
honour to a name which has always been associated with that honest pursuit
of science which results from an earnest desire to discover truth.

VulpiarHs Experiments on the Heart. — M. Vulpian lately described to the
Societe Philomathique his curious experiments on dogs. These experiments
were conducted with a view to ascertain the mode of origin and cause of
inflammation of the heart. In each case the animal was laid on its back, and
the flesh having been opened with a scalpel just over the point at which the
apex of the heart strikes the chest, a trochar was driven into the cavity of
the heart. This being effected, small portions of copper wire, pieces of wood,
and so forth, were introduced into the heart, and the instrument was then
removed. The animals being then released, some of them died and some
recovered. Post-mortem examination showed that in both cases the wires
had penetrated the substance of the heart, and in others had been forced by
the blood-current into the arteries, in some of which their further passage
was obstructed. In one instance, the copper wire lodged in the subclavian
artery, and produced a well-marked endo-arteritis, consisting of a softening
of the walls, fissure of the inner membrane, and a sort of vegetation.
— Report of meeting of the Societe Philomathique , July 6.

The cause of Osteomalacea is thus explained by M. Drivon in a paper
published in the Gazette Medicate de Lyon , for July : — The diseased bones
contain lactates, and probably lactic acid in considerable quantity ; these
help to dissolve the earthy carbonates and phosphates, which being then
resorbed, produce the softened condition characteristic of this malady.

The Poison of the Spotted Salamander. — The poisonous substance of the

SCIENTIFIC SUMMARY.

471

secretion of the Salamandra maculata has been chemically examined by M.
Zalesky. M. Zalesky has succeeded in isolating the active principle, which is
an amorphous colourless mass soluble in water. M. Zalesky calls it salaman-
drine , and states that it possesses, in an intense degree, the poisonous
properties of the secretion from which it is extracted.

METALLURGY, MINERALOGY, AND MINING.

Aluminium Bronze in Machinery. — M. Hulot, of the French Imperial Mint,
has called attention to the fact that the perforating tools employed in the
division of postage-stamp st are rapidly blunted by the gum used to render
the stamp adhesive. Indeed, so rapidly is the effect produced, that after a
few hours’ work the tools, instead of piercing the paper, only crush it. M.
Hulot replaces the steel by aluminium-bronze at 10 per cent., and the new
tool, striking 126,000 blows per day, or 180,000,000 holes, has worked for
several months without need of repairs. Aluminium-bronze does not unite
freely with spider by the old process ; but if we take equal quantities of
zinc-amalgam and common solder, aluminium-bronze can be admirably sol-
dered together by it. This solder becomes better, again, if it is alloyed with
once or twice its weight of tin. Thus there are three excellent solders —
1st, solder with half its weight of amalgam ; 2nd, with a fourth ; 3rd,
with an eighth.

The Manufacture of Zinc. — A paper on the relative value of the Belgian
and Silesian processes for the manufacture of zinc has lately appeared in
the Berg- und llutten-Zeitung (1867, No. 24). From this it appears that
the Belgian furnaces, with sixty retorts, in seven or eight horizontal rows,
require less fuel, have a more intense heat, a quicker process, and a greater
yield, than the Silesian apparatus. On the other hand, the Silesian
furnaces require less skilful workmen, but burn a smaller quantity of coal.
The Silesian process extracts more zinc from the ore, whilst the Belgian
furnaces have for a given time a greater productiveness. When the ore
forms tough slags, the Silesian method is preferable.

The Economisation of Sulphurous Acid in Copper Smelting. — At the late
meeting of the British Association, Mr. P. Spence gave an account of a pro-
cess for saving the sulphurous acid, which seems likely to come into use.
The following is the plan adopted : — In the calcining furnace sulphur and
arsenic are dissipated into the air, but a portion of the sulphur remains,
which in the smelting furnace sinks below the silicate of iron, to be run off
with the copper, and afterwards, when the regulus is again calcined, more of
the sulphur is given off. By catching this vapour of sulphur in a draught
of heated air passed along the furnaces, the sulphurous acid which is formed
is introduced into the leading chambers, when it is converted into sulphuric
acid.

The Perseberg Iron Mines , Sweden. — Dr. C. Le Neve Foster read a paper
on the above, before the British Association at Dundee. The author de-
scribed some important deposits of magnetic iron-ore which are now being
worked near Philipstadt, in Sweden. The ore occurs in beds, which follow

472

POPULAR SCIENCE REVIEW.

the various contortions of the surrounding rocks. It is found in Halleflindt
— a rock which is considered by the Swedish geologists to be a compact
variety of gneiss. The ore is always accompanied by a rock consisting of
garnet, hornblende, augite, and epidote. The author compared the large
deposits of Perseberg to "a deposit at the Crown’s Pock, Botallack Mine,
near St. Just, Cornwall, where magnetite is accompanied by the same
minerals, and occurs under the same conditions as at Perseberg, only on a
much smaller scale.

Analysis for Black Spindle. — At one of the recent meetings of the French
Academy, M. Pisani gave the results of his analysis of a black spinelle from
the Haute Loire. The specimen was remarkable from its crystalline form,
which was that of an octohedral pyramid, and it is found also in the igneous
rocks of Auvergne. The following is its composition : —

Alumina 59*06

Ferric oxide 10-72

Ferrous oxide * 13-60

Magnesia ........ 17-20

Copper'- Nickel Alloy. — The following method for the production of this
alloy has been described by M. Stromeyer in a late number of the Chemical
News, and is that in general use at Dittenburg Nassau : — 1. Bate melting :
roasting the ore, and smelting it to coarse metal. 2. Concentration melting :
roasting the coarse metal, and smelting it to concentration of a regulus. 3.
Refining melting : separation of the iron from the concentrated regulus. 4.
Roasting and reducing process : transformation of the regulus into oxides of
copper and nickel by roasting, and the reduction of the latter to copper-
nickel. The further details of the processes will be found in the Chemical
Neivs, August 2.

Composition of Specular Iron. — The following result of the analysis of
the iron used for cast-steel cannons has been given in a German chemical
journal. The specimen was dissolved by electrolysis in hydrochloric acid : —

Carbon # . . . 3-758

Iron ......... 87*997

Manganese 6-555

Phosphorus . . 0-578

Silicon . . . 0-497

Sulphur 0-171

Calcium 0-127

Copper 0-120

Arsenic 0*118

Magnesium 0-052

Antimony 0*027

Silver, lead, bismuth trace.

Vide Annalen der Chemief bd. 140, p. 180.

Russian Mineralogy. — The French Academy has been presented by M.
Kokscharow with the fifth volume of his Materialien zur Mineralogie Russ-
lands.

SCIENTIFIC SUMMARY.

473

Petroleum for Steam Engines. — Some experiments have been lately made
in America which seem to show that petroleum has many advantages as a
fuel oyer coal. A gunboat called the Palos was used for the experiments.
She had been built for the Government, to make a speed of eight knots an
hour, and with coal could never be forced beyond that. First she was tied
to the dock, and the possibility of getting-up steam with petroleum was
demonstrated. She was then sent on a trial trip down the harbour. Steam
was got up with petroleum in 25 minutes, and the Palos steamed down the
harbour and back, a distance of 25 nautical miles, in 1 hour and 55 minutes.
In making this trip she consumed but four barrels of petroleum. The fires
are reported to be kindled and extinguished with nearly the same ease as
lighting and extinguishing a gas-burner. The furnaces of the Palos,
originally built for burning coal, were fitted at comparatively small expense
with burners, to which the petroleum was led by pipes from the tanks on
deck. The burners, by their own heat, turn the petroleum in the pipes into
gas, and in this form it is burnt. The flames produced are intensely hot,
and the petroleum burnt on the trip produced as much steam as 20 times its
bulk in coals — a great saving of room in ocean voyages. The dangerous
properties of the petroleum appear to be the only drawback to its use in this
way, for coal-burning furnaces can be adapted to its use at but a trifling-
expense. The supply of petroleum is now so much greater than the demand
that, even with three-fourths of the wells in the producing regions aban-
doned, it can be bought for 2d. a gallon. Its cheapness is, therefore, another
strong inducement to use it for generating steam.

Anticrustation Mixture for Boilers. — The following recipe is given in a
number of Eisner's chemisch-technische Notizen: — 125 kilos, of crystallised
chloride of barium dissolved in 50 kilos, of water with addition of 25 kilos,
of hydrochloric acid (specific gravity T20). To every 1000 litres = 1 cubic
metre = 35 -5 cubic feet English, 15 litres of this acid solution should be
applied.

Constitution of Fire-Clays. — In a paper published in a late number of
Silliman's Journal , Messrs. Johnson and Blake state that compounds, such as
pipe-clay, fire-clay, and kaolin, all contain a peculiar crystalline substance,
which they term kaolinite. Seen under the microscope by reflected light
these clays appear white, but when the light is sent through them they appear
translucent. Interspersed among the particles may be seen curiously plate-
shaped particles 0*0001 of an inch in breadth.

Blast Furnace. — It is stated in the Bevue Universelle that Morgan’s method
of increasing the production of ^blast-furnaces sixfold, is by giving them
greater dimensions, for instance, 9| metres in diameter, blowing into the
furnace by 12 tuyeres. A hollow cone is besides constructed in the middle
part of the bottom of the furnace, by means of which a blast is also intro-
duced into the furnace.

Artificial Gold. — The alloy bearing this name has recently attracted some
attention in this country from the supposition that its employment is likely
to benefit on tin and copper workers. A contemporary gives the following
account of it : — It is composed of pure copper, 100 parts; pure tin, 17
parts ; magnesia, 6 parts ; tartar of commerce, 9 parts ; sal ammoniac,
3-6 parts ; and quicklime, T6 part. The copper is first melted, then the

474

POPULAR SCIENCE REVIEW.

lime, magnesia, sal ammoniac, and tartar are added, little at a time, and
the whole is briskly stirred for about half-an-hour, so as to mix thoroughly,
after which the tin is thrown on the surface in small grains, stirring until
entirely fused. The crucible is now covered, and the fusion kept up for
about thirty-five minutes, when the dross is skimmed off, and the alloy
found ready for use. It is quite malleable and ductile, and may be drawn,
stamped, chased, beaten into powder, or into leaves, like gold-leaf. In all
of which conditions it is not distinguishable from gold even by good judges,
except by its inferior weight. The alloy has already been largely applied in
the United States, and requires only to be known in Great Britain to become
& favourite. — Vide the Engineer , July 19.

METEOROLOGY.

Classification of Meteorites. — A classification of meteorites which will be
found useful by those engaged in the study of these bodies, has been given
by M. Daubree in a paper read before the French Academy in July. M.
Daubree divides all meteorites into two primary groups, Siderites and Aside-
rites — the former being characterised by the presence of metallic iron, and
the latter by its absence. The Asiderites contains one group only, which is
termed Asideres. The Siderites are divided into two sections : in the first
the specimens do not enclose stony particles, and in this we find the group
of Holosideres ; in the second both iron and stony matter are present. This,
then, includes two groups : Syssideres, in which the iron is seen as a con-
tinuous mass 5 and Sporadosideres, in which the iron is present in the form
of scattered grains.

A Town without Ozone. — From the experiments which have been made
since 1852 by the Hydrometric Commissioner of Lyons it would appear that
the atmosphere of this town is devoid of ozone. The results more recently
arrived at by the officials of the Imperial Observatory point to the same fact.
The observations conducted by these workers have not yet been published
in full. Meanwhile, M. Fournet gives the conclusions arrived at by his
resumed observations at Lyons and the suburbs, with the co-operation of
M. Lambert and Rassinier. While ozone was very abundant at Sauvage,
on the heights of Tararae, a range of hills separating the basins of the Loire
and Rhone, traces were barely perceptible once or twice a month at Lyons.
It is well known that it has been often maintained that the arrival of the
cholera was coincident with the disappearance of ozone in the air. The
example of Lyons does not agree well with this assertion ; this city is not
subject to cholera, and, at the same time, its atmosphere is always deprived
of oxygen. — Vide Foreign Correspondence, Chemical News, July.

Rainfall of the 1 6th July. — In his “ Magazine ” for August, Mr. Symons
dwells upon the more remarkable features of this severe rainfall. Without
attempting to explain the fact that in some localities the rainfall was twice
that of others, at a distance of a few miles, he gives the more striking
examples. For instance, twice as much rain fell at Deptford as at Camden
Town, one having 4 inches and the other 2|, the distance between the two
being only seven miles. Again, at Maidstone, the fall was equal to 2'7

SCIENTIFIC SUMMARY.

475

inches, while at Linton Park, seven miles off, the fall was P5 inches. At
Hartlip the guages recorded over 5 inches of rain j hut at Tong, a distance
of six miles, the records show a fall of only 1*64. As we have said, Mr.
Symons does not explain these singular differences between the rainfall of
contiguous stations, but we think the fact may depend on the same principle
as the ordinary snow-drift.

Hurricanes of the Indian Ocean. — At the meeting of the British Associa-
tion, Mr. Meldrum read a paper pointing out facts of considerable meteorolo-
gical interest. After showing how these hurricanes originated between the
S.E. trade wind and N.W. monsoon, how the wind in them rotated from left
to right, or with the hands of a watch, how they travelled at first to S.W.
and then curved to S. and S.E., Mr. Meldrum alluded to their form, showing
that the wind blew spirally, and illustrated the subject by interesting quo-
tations from the log-book of the Earl of Dalhousie, a vessel which, he
believed, belonged to the port of Dundee, and which in May 1863 had
scudded round and round the centre of a revolving storm three times, at
the rate of 10 to 13 knots, nearing the centre as she went round it. As the
S.E. trade wind frequently blew strongly over many degrees of longitude
during a hurricane, with a falling barometer, it was impossible to know the
bearing of the centre when a vessel was in front of a storm, and at some
distance from the centre, and Mr. Meldrum could adduce instances of
great loss of life and property arising from vessels in those circumstances
adopting the recommendation usually given of running to the westward or
north-west. In could not also be made too widely known that a large
portion, perhaps the largest, of the losses caused by hurricanes in those
seas arose from the fact that homeward bound vessels took apparent
advantage of increasing N.E. winds between 10° and 16° S. and, running to
the south-west, got in front of the storm, in which they were often dis-
masted, if they did not founder ; whereas, by lying to for a few hours, or
proceeding cautiously to the southward, the storm would have been avoided.

S ingidar Effects of Lightning. — Sir David Brewster has published an
account of the effects of lightning in Forfarshire which is of much interest.
In the summer of 1827 a hay-stack was struck by lightning. The stack
was on fire, but before much of the hay was consumed the fire was extin-
guished by the farm servants. Upon examining the hay-stack, a circular
passage was observed in the middle of it, as if it had been cut out with a
sharp instrument. This circular passage extended to the bottom of the
stack, and terminated in a hole in the ground. Captain Thomson, of Mon-
trose, who had a farm in the neighbourhood, examined the stack, and found
in the hole a substance which he described as resembling lava. A portion
of this substance was sent by Captain Thomson to Sir David’s brother, Dr.
Brewster, of Craig, who forwarded it to Sir David, with the preceding state-
ment. The substance found in the hole was a mass of silex obviously
formed by the fusion of the silex in the hay. It had a highly greenish
tinge, and contained burnt portions of the hay. Sir David presented the
specimen to the museum of St. Andrews.

Observations on Atmospheric Electricity. — The observations made at Kew
on this subject have been contrasted by Professor Everett, of Nova Scotia,
with those made at Windsor, N.S. The Kew observations referred to ex-
tended from June 1862 to May 1864, inclusive, and were taken with Sir

476

POPULAR SCIENCE REVIEW.

Wm. Thomson’s self-recording apparatus, specimens of the'photographic
curves thus taken being exhibited at the meeting. The Windsor observa-
tions, taken by Dr. Everett with apparatus of a different kind, also invented
by Sir Wm. Thomson, but not self-recording, extended from October 1862
to August 1864. Monthly averages which had been taken showed that at
Kew there had in every month been two maxima in the day — one of them
between eight and ten A.M., and the other, which was more considerable,
between eight and ten p.m. At Windsor, on the contrary, the electricity
between eight and ten p.m. had in every month been weaker than either
between eight and ten a.m. or between two and three p.m. The annual
curve for Kew had its principal maximum in November, and another in
February or March. At Windsor the principal maximum was in February
or March, and the minimum in June and November. The annual curves for
the two places agreed pretty well from January to October, but were curved
in opposite directions from October to January.

A New Test for Ozone. — In the Comptes Rendus for July, Admiral Berigny
records numerous experiments upon the correct methods of detecting ozone
in the atmosphere, and states that he has found protoxide of thallium the
most delicate test. While, for example, ordinary oxygen produces little
effect on papers saturated with solution of this substance, ozone instantly
reveals its presence by giving a brown tint to the paper. Unfortunately,
li owever, for the practical usefulness of the new test, it is found that car-
bonic acid affects the protoxide of thallium in the same manner as ozone.
Hence, the discovery has little more than a purely theoretical value.

Relation of Ozone to Direction of Wind. — The results arrived at by obser-
vations made at sea by Mr. W. F. Moffat, B.N., and reported by Dr.
Moffat to the British Association, are very remarkable. It was found that
as the wind veered with increasing readings of the barometer from south
points of the compass through W. to N., ozone disappeared, and continued
absent while the wind was in points between N. and E., and that it re-
appeared as the wind veered with decreasing readings of the barometer to
S. points. The disappearance and reappearance of ozone with those con-
ditions were so regular, that the changes appeared to be the result of an
invariable atmospheric law, and Mr. Moffat was induced to examine the law
of rotation of the wind, so clearly developed by Dove, and the results of the
examination led him to believe that the polar current is the non-ozoniferous,
or that of minimum of ozone, and that the equatorial is the ozoniferous, or
that of the maximum of ozone. According to the rotation theory, the N.
polar current forms the N.E. “ Trade,” and the S. polar the S.E. “ Trade,”
while the equatorials form the northern and southern hemispheres to upper
or returning “ Trades.” These returning “Trades ” come to the earth’s
surface in the northern and southern hemispheres about the 28° or 30°
of latitude — the latitude varies with the season — N. and S. of the equator.
If these deductions are to be relied upon, the N.E. and S.E. 11 Trades ” ought
to be the minimum of ozone currents, and the returning (t Trades” the
maximum of ozone currents, the one in the northern hemisphere forming
the S.W. wind, and the other in the southern hemisphere a N.W. wind.

SCIENTIFIC SUMMARY.

477

MICROSCOPY.

New Class and Demonstrating Microscope. — In teaching histology to large
classes of students, two forms of microscopes are required : one for the
laboratory, with which the student himself works,
and one for the class-room, which the lecturer
hands to the nearest student, who passes it to his
neighbour, and so on till it travels round the class.
The idea of combining these two forms in a single
microscope occurred to us as being both economical
and convenient. The instrument represented in the
adjoining cut was therefore prepared for us by
Mr. Collins, of Titchfield Street. Pig. 1 represents
the microscope as used in the laboratory, with a
double nose-piece bearing a 1 -inch and i-inch object-
glass. Fig. 2 shows the microscope as used in the

Pig. 1. As used in the Pig. 2. As used in the Lecture-room.

Laboratory.

NEW CLASS AND DEMONSTRATING MICROSCOPE.

lecture-room : the leg is drawn out from the sliding tube, which works in
the knuckle joint in the solid metal foot, and bears the mirror; on this
there is fitted a small oil-lamp, and the instrument being grasped by the
curved portion between the body and stage, and used like a telescope, trans-
parent objects placed on the stage are seen with the greatest distinctness.
It is remarkable, but it is no less true, that no amount of ordinary flickering
of the flame is perceptible by the observer. The instrument is provided
with a good 1-inch and also 5-inch objective, which show the markings on
Pleurosigma formosum most satisfactorily. The instrument is intended to
meet the want of teachers in medical schools
and public institutions, and has just been
selected for the histological laboratory at
St. Mary’s Hospital.

An Adjustable Notating Microscope-table
has been devised by Messrs. Loam and
Fearns, and is likely to be useful to those
who use a circular table when exhibiting NEW rotating microscope table.
microscopic objects to a number of persons.

It is triangular in form and, when placed in position, its apex corresponds to

478

POPULAR SCIENCE REVIEW.

the centre of the table on which it rests ; at its base it rests on two rollers,
and its apex swings on a vertical pivot. When, therefore, the microscope
and lamp are placed on this u rotating table ” and adjusted to each other,
the two may be sent round from one observer to another, as in a roulette-
board. The pivot being movable, the rotating table can be made of any
radius, and can then be adapted to the size of the loo-table on which it is
placed. Amateur microscopists will do well to provide themselves with
this little addition to the list of microscope accessories.

A Telescopic Lamp. — A microscope lamp, which may be found convenient,
has been constructed by Messrs. Murray and Heath, of Jermyn Street. In

the form of the lamp itself there is little new ; but the stand is peculiar.
It consists of three telescopic sliding tubes, the innermost of which is the
cylinder which contains the oil. The object of this arrangement is that,
without the ordinary contrivances, the light may be elevated or depressed.
The tubes are provided with a screw-thread which prevents the lamp from
descending from the point at which it is fixed.

SCIENTIFIC SUMMARY.

479

A Pocket Microscope of a very cheap description has been constructed by
Messrs. Frith. It is intended to be used by amateurs in the examination of
mites and “ wheel insects.” It is simply an extremely small lens, whose cor-
rections are imperfect. This is approximated by a screw to a glass disc
on which the object is placed. The makers’ description will interest
readers who are versed in microscopical terminology. It states that the
instrument is divided into four parts, viz., “the Eye-piece, composed of two
screws in the centre, between which is placed the lens, or magnifying glass ;
2nd — the Object-glass, on the centre of which the objects are placed, and
which is fixed to No. 3, or the body or tube ; 4th — the Condenser of
natural light, at the extreme end, which must be used only by daylight and
taken off by gaslight, when the observer must point the open end of the
tube towards the gas or candlelight, to receive the rays direct.” We may
state that the condenser is simply a diaphragm, with an aperture of £ inch
diameter.

PHOTOGRAPHY.

Improved Process for making Photographic Transfers. — Amongst recent
patents connected with photography is one taken out by Mr. G. Morvan, of
New Jersey, U.S., for making transfers to lithographic stone, &c. A nega-
tive being obtained from the design, it is printed by light on paper prepared
as follows : — A suitable paper, albumenised or not, is placed in a] bath of
sour milk, for the purpose of giving it greater strength and solidity. When
taken from this, it is allowed to dry at an ordinary temperature, and is
coated with the following material : half a pound of French glue dissolved
in a pint of water, added while boiling to a solution of one-third of an ounce
of permanganate of potash in a quart of water, and used cool. The paper
thus coated is dried in the dark, and exposed under the negative. After
removing, and before developing, cover the first coating with another com-
posed of equal parts of bitumen, white wax, and Burgundy pitch, dissolved
in a sufficient quantity of essence of lavender to allow of its being spread
smoothly over the surface. Let this also dry in the dark j after which place
it with the black side upwards in a bath of cold water, which dissolves
those parts on which the light has not acted, and carries with it the super-
incumbent mixture of wax, bitumen, and Burgundy pitch. The proof is
finished by a few strokes of a sponge, and, when dry, can be transferred to
lithographic stone, or to zinc or other metal, by contact and pressure in the
ordinary manner ; to be printed from, if on stone, and to be engraved with
acids on the metal, the composition protecting the parts it covers from the
action of the etching fluid.

Photography by Artificial Light. — Professor Falkland, in the course of
some lectures on coal gas, delivered at the Royal Institution, pointed out
the value of a new and intensely brilliant light to which photographers have
recently had their attention directed, as being very actinic and manageable,
and in other ways peculiarly fitted for photographic uses. Bisulphide
of carbon warmed until it gives off vapour freely, is ignited, when it burns

480

POPULAR SCIENCE REVIEW.

•with a pale blue flame giving a feeble light. A jet of g as, obtained by the
action of nitric acid on copper, being allowed to play through this burning
vapour, the result is a very brilliant actinic light, which can be kept up for
a considerable time with a very small amount of trouble. It must be
remembered, in using this light, that the burning bisulphide of carbon gives
off fumes of sulphurous acid.

The Nature of the Latent Image. — In our last we gave what were called
11 some entirely new views” on this subject, as advanced by an American,
Mr. Carey Lea. This gentleman has since been very active in promulgating
his theory; and although it has been very clearly shown in the English
j oumals to which he contributes that, as we suspected (see note page 344),
he has no claim to be regarded as the originator of such views, still, in the
American journals, he continues to assume the position of one who first com-
municated them to the public, and to strangely exaggerate their importance.
Air. W. H. Harrison laid claim to having first published the ideas Air. Lea
pertinaciously claims as his own, and a controversy ensued, in which the
latter gentleman strove to show that Mr. Harrison’s views entirely differed
from his own, and that they were false, basing his argument upon the
assumption that Air. Harrison held the action of light to be simply an
augmentation of the amplitude of the ordinary vibrations of molecules com-
posing the sensitive surface — an assumption not warranted by Air. Harrison’s
remarks. At an early stage of the controversy, Air. Harrison gracefully
withdrew his claims to priority of publication in favour of Air. Alungo
Ponton, F.R.S.E., who, in reply to Air. Lea, says * u The vibrations which
we (himself and Air. Harrison) suppose to be effected by the light, are not
the ordinary vibrations between molecule and molecule of the sensitive
compound incident to its temperature ; but a totally distinct set of very
minute vibrations established between atom and atom of the constituent of
each molecule 'of the substance. Whether such minute vibrations exist at all
before exposure to the light, is unimportant ; but it is evident that the greater
the motive energy of the light brought to bear upon them, the greater will
be the amplitude of those vibrations ; consequently the greater will be the
facility for effecting a separation between the atoms. The rate of vibration
is a different affair, and will depend on the nature of the constituent atoms,
and the strength of the chemical attraction by which they are held together.
The more nearly the natural rate at which these atoms tend to vibrate
approaches to the rate of the violent waves, the more readily will they take
up the motion from those waves and have their amplitude thereby enlarged.
But their rate will not be altered by the energy which they absorb from the
ethereal waves ; while, even if it were quickened, such acceleration of the
rate could not produce any increased tendency to decomposition. An increase
of motive energy can affect a vibration in only one of two ways : it must
either quicken its rate, or enlarge its amplitude. Now the doubling or even
the trebling of the rate of vibration between two heterogeneous atoms
constituting a compound molecule, could have no effect in promoting their
permanent^separation : but every increase in the amplitude of the vibration

In the British Journal of Photography.

SCIENTIFIC SUMMAKY.

481

removes the one atom to a greater distance from the other, at the moment
of farthest departure from the point of rest ; while such an increase of
distance must produce a corresponding momentary weakness in the attrac-
tion by which the two atoms are held together, so rendering more easy their
permanent separation. The tendency to separation would also be increased
by a lowering of the rate of vibration simultaneously with the increase of
amplitude, because it would prolong the moment of weakest attraction. It
is obvious that no augmentation in the amplitude of those ordinary vibra-
tions of the molecules of a compound body which are incident to its
temperature could produce the same effect ; because the atoms of each
molecule are not in this manner made to vary their distance one from an-
other. ... In order that the vibrations between the atoms constituting
a compound molecule may have their motion amplified by those of the
lumineferous ether, it is not necessary that the latter should be exactly
synchronous with the natural rate at which the atoms tend to vibrate,
although the more nearly they are synchronous the more effective they will
be. Where we have 800 billions of vibrations in a second, a few millions
more or less can be of little importance.” Mr. Ponton concludes that the
action of light in fluorescence, is quite different from what it is in photo-
graphy. u In fluorescence, the molecules, or their constituent atoms, on
taking up the motion from the ethereal waves, change its rate. The incident
light is absorbed and a new set of ethereal waves is propagated by the vibrat-
ing atoms or molecules, and these new waves have a rate of vibration
slower than that of the incident waves ; hence the colour corresponds to
these more leisurely vibrations ; hence, also, incident ethereal waves too
rapid in their rate of vibration to affect the optic nerve, may stimulate the
molecules or atoms to propagate waves of that slower rate of vibration
which is capable of exciting the nerve into action. The waves whose
vibrations are thus appropriated and lowered in their rate by the fluorescent
body, are those most active in photography ; and hence fluorescent surfaces
are photographically inert, the waves which they propagate being of too
slow a period to be effective in this manner. The continuance of the
vibratory action, after the exciting light has been removed, is similar to
phosphorescence. Every motion once begun has a tendency to continue
till checked by some retarding force. It is, therefore, not at all wonderful
that the vibrations between the constituent atoms of the molecules of the
sensitive substance should continue for a considerable time after being re-
moved from the excitement of the light. The phenomenon is of the same
nature as the retention of its heat by a body for a considerable time after it
has been taken out of the fire.” * At an earlier stage of the controversy,
other views were advanced, but we have not space for further particulars.

Awards of Photographic Jurors at the Paris Exhibition. — We give a list
of the English photographers who have carried off honours at the Paris

* E. C., writing in the British Journal of Photography , in reply to the
above statement, asks : u How is it, then, that dry plates have been
developed several years after exposure, and commonly months' afterwards,
without more than ordinary difficulty P It is evident that in the film the
c excitement ’ must still be kept up without appreciable diminution .”

482

POPULAR SCIENCE REVIEW.

International Exhibition. Messrs. Bedford, England, Mudd, Thurston,
Thompson, and Robinson were each awarded a silver medal for landscape
photographs. Figure and portrait photographers were not recognised as
worthy the silver medals, and therefore received medals in bronze. The
names of those thus distinguished are Messrs. Blanchard and Mayall, the
latter award being for enlargements from small negatives. Bronze medals
were also awarded to Messrs. Grigg3, Col. Briggs, Bourne and Shepherd,
Macfarlane, Heath, Col. Stuart Wortley, and White, for landscape photo-
graphy. For cabinet work a bronze medal was awarded to Meagher, and
for lenses to Mr. T. Ross ; Mr. Cherril received a bronze medal for carbon
prints, Caldesi one for medallion photographs, and M. Joubert one for his
enamel process. A silver medal was awarded to Mr. Swan for an improved
carbon -printing process, to Mr. Woodbury for a new mode of printing, and
to Mr. Dallmeyer for a triplet object-glass. The following names were
associated with “ honourable mention ” : — Beasley, Bean, Brownrigg,
Cameron, Coghill, Cramb, Cruttenden, Grisdale, Hemphill, Hosmer the
Pantoscopic Company, Pouncy, Ross (of Edinburgh), Rouch, Royal Artil-
lery, Soloman, H. Swann, Thomas, S. Thompson, Verschoyle, Wardlv, and
Wilson. There have been, as was to be expected, perhaps, many charges
of unfairness and undue partiality brought forward in connection with these
awards, and some very striking inconsistencies have been noted ; but the
worst case published is that which Mr. Thomas Ross has called public
attention to, viz., the jurors deciding upon giving a medal for excellence
in lenses which they had not examined, simply because they were exhibited
by a manufacturer of known repute. This medal, the only one awarded for
general excellence in photographic lenses, Mr. Ross generously declined to
receive, upon the ground of the injustice of a mode of proceeding which
deprived every young and unknown optician of that fair chance in honour-
able competition which each exhibitor has a right to demand and to expect.

Photography at the British Association. — Photography has not played a
very prominent part at the meeting at Dundee, although its productions
were used to illustrate papers in most of the sections. Professor J. C.
Maxwell, F.R.S., introduced a new stereoscope in section A. The effect of
looking through this instrument was very novel and striking. In the ordi-
nary stereoscope the observer applies his eyes to the two lenses, seeing one
picture with the left, and the other with the right eye. In Professor Max-
well’s the observer stands a short distance from the apparatus and looks
with both eyes through the large lens. The instrument consists of a board
about two feet long, on which is placed — 1. A vertical frame, to hold the
side turned upside down. 2. A sliding piece near the middle of the board,
containing two lenses of six inches focal length placed side by side, with
their centres about 1| inch apart. 3. A frame containing a lens of about
eight inches focal length and three inches diameter. The eye should be
placed about two feet from the large lens. With his right eye he sees the
real image of the left-hand picture formed by the left-hand lens in the air,
close to the large lens, and with the left eye he sees the real image of the
other picture formed by the other lens in the same place. The image may
be magnified or diminished at pleasure by sliding the piece containing the
two lenses nearer to or farther from the pictures. '

SCIENTIFIC SUMMARY.

483

M. Claudet called attention to an improved instrument which is used to
equalise the focus of a lens on different planes. Sir David Brewster made
some remarks on the enamel photographs of Mr. McCraw, of Edinburgh,
and M. Claudet read a short communication on the result of some experi-
ments with non-achromatic lenses of rock-crystal and topaz, the results of
which, he said, were very promising, which experiments he had been in-
duced to make by the theory Sir David Brewster published many years
since. In Section B, Mr. J. Spiller, F.C.S., read a paper on certain new
processes in photography. These processes were the various modifications
of Mr. Woodbury’s, micro-photosculpture, photolithography as practised in
the Boyal Arsenal at Woolwich, and a process of printing on silk, satin, or
cambric, practised by Mr. H. B. Pritchard, of the War Department.

Action of Light on Honey. — M. Scheibler has attributed the crystallisms of
honey to the photographic action of light, and thus explains why bees
carefully exclude light from their hives, as, if light obtained access, the
syrup on which the young bees feed would, by becoming more or less solid,
seal up the cells, and probably prove fatal to the inmates of the hive.

PHYSICS.

Action of Glass Rods in Liberating Gases from Solution. — Mr. Chas. Tom-
linson’s researches on this point show that the phenomena of liberation of
the gas depend, not on any peculiar action in air or gas, but on whether the
rods are clean or not. The theory that he proposes to substitute rests on the
distinction between a chemically clean solid and one that is clean in the
ordinary sense of the word. If the solid be chemically clean, there is perfect
adhesion between it and the solution, and there is no liberation of gas ; if the
solid be not chemically clean, then the adhesion is imperfect, and there is a
separation of gas. If the water is not attracted by the solid, the gas is ; for
although the rod may not be clean enough for water to adhere to it, yet gas
will adhere to a dirty or a greasy rod. If the rod be made chemically clean,
it soon ceases to be so by exposure to the air ; and this circumstance, accord-
ing to Mr. Tomlinson, has led the numerous writers on supersaturated
solutions of salts into error as to the action of nuclei , &c., in inducing crys-
tallisation. If the nucleus be chemically clean, the solution wets it perfectly,
and there is no separation of salt from the water ; if the nucleus be not
chemically clean, there is separation. — Vide Philosophical Magazine , August.

Lnfluence of Capillary Action on Chemical Decomposition. — M. Becquerel
continues his researches on the action of capillarity in chemical decomposi-
tions. In his third communication he gave a new set of illustrations of the
law already expressed by him. He stated that the phenomena described by
him in his earlier papers are due to the influence of three agencies — affinity,
capillarity, and electricity. To demonstrate the intervention of electricity,
M. Becquerel has made the following experiment: he immersed his split
bell-glass, containing nitrate of copper, in a second bell containing a solution
of monosulphide, as in the first experiments ; then he dips the two extremities
of a silver wire, one into the nitrate, and the other into the monosulphide. A
YOL. YI. NO. XXY. M M

484

POPULAR SCIENCE REVIEW.

constant electric current is formed : (1) The deposit of silver is made not in
the capillary slit, hut on the iron ; (2) When the wire is removed the
deposit is formed in the slit and on the edges along the side of the split hell-
glass. The capillary action is as powerful as an electrical action. M.
Becquerel continues to improve his experiments ; for the split hell-glass he
substitutes prisms of crystal glass pierced with a small hole ; the slit or
fissure is replaced by plates of glass with edges in contact, or even by sand ;
and he has thus obtained effects of silvering, gilding, and platinising. — Vide
Comptes Rendus , July 1, and Chemical News .

A new Polarising Photometer was described by its inventor, Mr. W.
Crookes, F.B.S., at the British Association meeting at Dundee. He was
unable to exhibit the instrument itself, but he gave the following description
of it : Two discs, emitting natural — not polarised — light, are placed in front,
and at a considerable distance behind is a doubly-refracting prism of
Iceland spar, rendered achromatic by a piece of glass, which will separate
the light emitted by the two discs into three ; but, for the purposes of the
instrument, the outer two must be disregarded. The difference of intensity
between the original self-emitting discs is proportioned to the free polarised
light found in the central disc of light. This is again split up, and the
difference of intensity between the first discs is ascertained from the difference
between these final ones. In comparing the light of two stars, Mr. Crookes
makes use of Arago’s Polarimeter, which, twisted in one direction, gradually
cuts off one kind of light, and when twisted in the opposite direction, cuts
off the other kind of light, so that the intensity of the light is measured by
the angle through which the instrument must be turned.

Recent Memoir on Optics. — Herr Dove, the celebrated physicist and me-
teorologist, has presented to the Academy of Berlin a memoir in which he
discusses the following important points : — 1. The formation of white by
uniting the colours of the spectrum; 2. The subjective colours in the
electric spark ; 3. The inversions in monocular or binocular vision of per-
spective drawings or transparent bodies; and 4. The polarization of light
by successive reflections. — PInstitut, August.

Improvements in Voltaic Piles. — Certain improvements have been sug-
gested by M. Zaliwski Mikorski. The latest experiments of the physicist
show that by increasing the height of the elements without altering their
base, a current proportionate to the height may be obtained. He recommends
the following method for increasing the energy and permanency of a Bunsen’s
battery Place two porous vessels one within the other : into the first, con-
taining the carbon, pour nitric acid ; into the second, sulphuric acid ; finally,
into the outer vessel, containing the zinc, pour sal-ammoniac. There is no
effervescence, and the zinc undergoes no useless destruction.

An excellent Popular Illustration. — Sir W. Thomson, in describing a small
electrical machine to the British Association, employed the following happy
analogy to convey an idea of the purpose and mode of action of the new in-
strument : — The principle of the machine is that of the u Successful Mer-
chant ” who commenced life with a capital of \d., and, after a month’s per-
severing industry, realised the handsome sum of 1/., and continued to go on
increasing his capital at a compound rate of interest. The object of the in-
strument referred to is not indeed to increase money but electricity, and

SCIENTIFIC SUMMARY.

485

that increase was at a compound rate. Precisely in conformity to the law
which applied to compound interest and the increase of the successful mer-
chant’s capital is the increase of electricity by this machine. Given the
smallest quantity of electricity, and the instrument increased it at the rate of
compound interest, and this increase went on at a perfectly uniform rate.
But just as the capitalist finds that he cannot always go on getting higher
and higher interest for his money, but must ultimately, perhaps, be content
with per cent, instead of 5, so was it to some extent with thi3 machine.
When a very high charge was reached, the increase of the quantity of avail'
able electricity was not so great, owing to sparks passing in various parts of
the machine, preventing the operator from retaining the full quantity of
electricity which was got by it. There is great necessity for an easy-
going electric machine, and that shown fulfilled this condition.

How the Earth's Rotation affects Gunnery. — Some may be found to doubt
that the movement of the earth affects the direction of a ball expelled from
a cannon ; nevertheless, the fact is correct. In the Astronomical Register
Mr. Kincaid says that a simple illustration of this effect may be made by
attaching to the same axis two wheels of different diameters, so that both
shall rotate together. If the one have a diameter of 3 feet, and the other of
1 foot, it is evident that any point on the circumference of the larger will,
during a revolution, move through three times as much space as a similar
point on the periphery of the lesser circle, and will, therefore, move with
three times the velocity. The figure of the earth may be considered as
made up of an infinite number of such wheels, diminishing in size from the
equator to the poles, and all revolving in 24 hours. Now, if a gun be fired
from the equator in the direction of the meridian, which is obviously that
of maximum deviation, at an object nearer the pole, it is plain that that ob-
ject, being situated on a smaller circle than the gun, but revolving in the
same interval of time, will move, during the flight of the projectile, through
less space eastwards than the shot, which will have imparted to it the
greater velocity of the larger circle from which it started, and the latter
will therefore tend to strike eastwards from its butt. — Astronomical Re-
gister, August.

The Physics of a Soap-bubble. — That the physics of a soap-bubble is a diffi-
cult problem to work out has been shown by Sir David Brewster’s repetition
of Plateau’s experiments. The changes of form which the films undergo are
especially difficult to explain, the ordinary theory being insufficient. Sir
David Brewster thinks that the colours of the soap-bubble are not produced
by different thicknesses of the film itself, but by the secretion from it of a
new substance flowing over the film, expanding under the influence of
gravity and molecular forces into coloured groups of various shapes, and
returning spontaneously when not returned forcibly into the parent film.

Production of Inductive Currents. — It has been discovered by Signor
Blaserga, of Padua, that inductive currents are not produced instantaneously.
Their development requires a definite period of time, which he has estimated
at about ^ of a second. He also states that when established an appreciable
time is occupied in arriving at the maximum.

The Luminosity of Phosphorus. — Dr. Moffat read a paper before the
British Association, and describes a number of experiments on the above.

m m 2

486

POPULAR SCIENCE REVIEW.

From these experiments it was shown that phosphorus in a luminous state
produced phosphorous and phosphoric acids, and ozone also ; that it was
non-luminous in a degree of temperature below 39° (F.), and that it was lu-
minous above 45° (F.) ; but the temperature of luminosity and non-luminosity
varied with the pressure of the atmosphere, and also with the direction
of the wind. A series of experiments, extending over four years, had been
made on the luminosity of phosphorus in connection with atmospheric con-
ditions, and from the results it would appear that the equatorial or sea
wind is that of phosphoresence and ozone, and that the polar or land wind
is that of non-luminosity and no ozone. As the ocean is the reservoir of
ozone, Dr. Moffat asks if it is not probable that its phosphorescence is the
chief source of its development — a probability strengthened by the fact
that the polar and land winds, in the shape of the NE. and SE. nodes, seem
to modify its development as the land-current does.

Expansion of Limestone when burnt. — Herren Dorlhan and Saminn point
out that two cylinders formed out of the same piece of limestone measured
27 millimetres in length and 17 millimetres in diameter. After being com-
pletely burned, their volume had increased nearly — viz., to 28 millimetres
and 17-7 millimetres.

Measuring the Transparency of the Air. — M. de la Dive, of Geneva, lately
sent a note to the French Academy, describing an apparatus for measuring
the transparency of the air. According to M. de la Rive, the great trans-
parency of the air before rain is due to the presence, in the air, of a quan-
tity of invisible vapour, which renders transparent the numerous germs
floating in the air, to whose presence light mists are attributed. — Vide
Comptes Rendus, tom. lxiv., No. 23.

The Electro-deposition of Copper. — It very frequently occurs that the copper
which is deposited by electric means is so brittle as to render it unfit for
manufacturing purposes. A very simple and ingenious method of preventing
this has been described by M. Bouillet, which we give our readers. M.
Bouillet has found that a small quantity of gelatine dissolved in the water
of the bath gives a copper of extensive malleability and nearly equal to
rolled copper.

A Telegraphic Thermometer has been, constructed by Professor Wheatstone,
and was described at the British Association meeting. The details of its ar-
rangement are too numerous for our columns, but the instrument is likely to
be of immense value in meteorological inquiries. Professor Wheatstone
gives the following account of its application to the purposes of meteoro-
logy : — In this class of instruments the indications are not spontaneously
conveyed to the observer, but they must be asked for j and whenever this is
done, the indications will be immediately transmitted to him, however
frequently the question is put. The uses to which this telegraphic thermo-
meter may be applied are, among others, the following : — The responder may
be placed at the top df a high mountain and left there for any length of
time, while its indications may be read at any station below. Thus, if there
should be no insuperable difficulties in placing the wires, the indications of
a thermometer placed at the summit of Mont Blanc may be read as often
as required at Chamouni. A year’s hourly observations under such circum-
stances would no doubt be of great value. If it be required to ascertain

SCIENTIFIC SUMMARY.

487

during a long-continued period tlie temperature of the earth at different
depths below its surface, several responders maybe permanently buried at the
required depths. It will not be requisite to have separate questioners for
each, as the same may be applied successively to all the different wires.
The responder, made perfectly watertight, in which there would be no
difficulty, might be lowered to the bottom of the sea, and its indications
read at any intervals during its descent. In the present mode of making
marine thermometric observations, it is necessary that the thermometer
should be raised whenever a fresh observation is required to be made.

ZOOLOGY AND COMPARATIVE ANATOMY.

Where to place Cryptoprocta ferox. — Since the singular carnivorous animal
Cryptoprocta ferox was described by Bennet, there has been a difficulty
as to referring the creature to its proper place in the order Carnivora.
Bennet’s specimens were all those of young animals, and the dentition being
incomplete, of course they offered no reliable characters for the zoologist.
The problem is now solved. MM. Milne-Edwards and Grandidier have
laid before the French Academy a tine memoir on this species ; in this they
describe minutely the anatomical character of Cryptoprocta , which they place
not in the family Viverridce , but in that of the Felidce. The Cryptoprocta is
a plantigrade animal, and therefore it is determined to divide the Felidce ,
like the Carnivora, into two groups, Plantigrada and Digitigrada, as is the
case with the order. The Cryptoprocta will then be placed in the first
division, being the only representative ; while the other genera will come
under the second section. — Vide Comptes Rendus, August 5.

The Muscular Systems of Birds and Mammals have been contrasted in a
paper laid before the Society Bhilomathique by M. Alix. The author arrives
at the not very novel conclusion, that the muscular system of birds presents
elements absent from that of mammals, and that the muscular system of
mammals presents elements absent from that of birds. — L'lnstitut, June 29.

Rearrangement of Asiatic Salamanders. — Mr. St. George Mivart professes
to place one of the Asiatic salamanders, the Plethodon persimilis of Gray, in
an entirely new genus, for which he proposes the name of Pectoglossa.

The Fore-limb of the Great Anteater has been submitted to a careful dis-
section by M. Pouchet, who enters into many important details. M. Pouchet
states that in regard to the shoulder, wrist, and elbow-joints the Myrmeco-
phaga presents many analogies with the Primates. — See the Comptes Rendus ,
July 1.

Mammalian Blood Disks. — We have received proofs from Professor Gulli-
ver, F.R.S., of a paper on this subject, which will appear in the Journal
of Anatomy for November. In this the author reiterates his belief that the
classification of Vertebrates, founded on the character of the blood-corpuscles,
still holds good. He divides Vertebrata into two groups: — (1) Pyrencemata,
those whose blood-disks are nucleated ; and (2) Apyrencemata, those whose
corpuscles contain no nuclei. The former division includes the birds, reptiles,
batrachians, and fish. The latter includes the mammalia only. Professor
Gulliver concludes by stating that the corpuscles are as valuable indications

488

POPULAR SCIENCE REYIEW.

of specific characters in animals as are the raphides in plants, and he refers
his readers to the article on the latter, which he wrote for the Popular
Science Review some time ago.

Birds' Nests and Birds' Plumage. — One of the finest papers ever published
on this most interesting point in Natural History, was that read by Mr.
Wallace before the British Association at Dundee. It would he impossible
to condense it into a paragraph, and we hope, therefore, that the author will
print it in full in some of the periodicals. It described the peculiarities of
plumage which protect birds when sitting on their eggs, and was another
convincing argument in favour of Mr. Darwin’s hypothesis.

New Fishes. — At a meeting of the Vienna Imperial Academy of Science,
Herr Steindacher recorded the discovery of several new species of fishes,
which he ranges under the genera of Glyptosternon , Caranx , Batrachus , Arius,
Batistes, Eeros, and Ctenolabrus.

The Ray Society' s future Publications. — The books issued by the Bay Society
are always so well selected, and so admirably executed, that naturalists are
glad to know what a treat they have to anticipate. We therefore give the
names of the works in preparation for future years, which are as follow : —
Professor Allman on the u British Corynidse.” The volume of plates to the
edition of the works of the late Bobert Brown, edited by J. J. Bennett, Esq.,
E.B.S. Bev. 0. P. Cambridge, a supplementary volume on “ British Spiders.”
Messrs. Douglas and Scott on the “ British Hemiptera Homoptera.” Dr.
Gsertner on “ Hybridism in Plants” (Bastarderzeugung), translated from the
German by W. Carruthers, Esq., F.L.S. Mr. Hancock on the “ British
Tunicata.” Sir John Lubbock on the u British Thysanura.” Dr. MTntosh
on the u British Annelids.” Dr. Masters on u Vegetable Teratology.” Mr.
St. George Mivart, u Monograph of the Tailed Amphibia.” Mr. Andrew
Murray on the “ Coniferse.” u A Synopsis of the Pauna and Flora of
Palestine,” by the Bev. H. B. Tristram, F.L.S. Professor Westwood on the
“ Mantidas,” with illustrations by Mr. E. A. Smith. The Council have
also under consideration a proposition for an important and expensive
botanical work, with reference to which the only difficulty is the financial
element.

The Boring of Annelids. — Mr. E. Bay Lankester read a paper before the
British Association on the mode by which annelids make borings in rocks.
The conclusion at which he arrived, which seems supported by probability,
is that worms like the Echinus lividus make their borings by means of
carbonic acid. Worms bore only rocks composed of carbonate of lime,
which, though insoluble in water, are readily dissolved by solution of car-
bonic acid. Mr. Lankester thought the subject of the boring of worms
quite uninvestigated, and instanced two genera which perforate rocks
extensively.

The Anatomy of the Pilot Whale formed the subject of a paper read by
Professor Turner. The anatomy of the stomach and of the great arteries
was described by the author. Professor Turner compared the stomach of
the pilot whale with that of the porpoise, and stated that the former con-
tained a greater number of compartments than the latter.

Dodo-like Birds of the Mascarene Islands. — The Committee appointed in
1865 to investigate this group, has produced little result beyond the col-

SCIENTIFIC SUMMARY.

489

lection of a number of bones from Rodriguez. Professor Newton made
some general remarks upon tbe specimens collected, and be especially dwelt
on an unexpected confirmation of tbe testimony of Leguat, by tbe discovery
of an extraordinary bony knob near tbe extremity of tbe wing. Leguat,
whose account of tbe u Solitaire’s ” babits was tbe only one we possessed,
mentioned a curious u ball,” as big as a u musket bullet,” wbicb the male
birds possessed under their wing feathers. Now, the existence of this ball
was proved by tbe bony knob exhibited, and thus tbe veracity of old Leguat
— who was a Huguenot refugee — on this point, as on so many others, was
confirmed. In conclusion, Professor Newton called attention to tbe fact that
at present we only knew of the didine bird of tbe island of Reunion, that it
was white. In tbe course of last year, Mr. Tegetmeier bad shown him an
old watercolour painting of a white dodo, and this, be was inclined to be-
lieve, might represent this lost species, of wbicb be trusted tbe French
naturalists in that island would succeed in obtaining actual relics.

The Shetland Dredging Committee. — Mr. J. G wyn Jeffreys read the prelimi-
nary report of tbe Committee for tbe present year. From this it seems that
tbe further investigation is carried on in tbe Shetland seas, tbe more deeply
interesting does tbe study of tbe fauna of that portion of tbe country become.
Dredging in tbe depths of those northern seas, in wbicb there is, almost in-
variably, a heavy sea — at one time sweeping across tbe Atlantic, at another
rolling away from Greenland, at another (as was tbe case for many weeks to-
gether during tbe present summer) running for Spitzbergen and tbe ice-floes
of tbe Arctic Oeean, accompanied by a keen cutting north-east wind — is not
altogether pleasant work for tbe naturalist. Yet, trying and difficult though
tbe dredging be, there is none to be compared with it in the British Islands,
and every fresh summer tbe Dredging Committee have spent in investigat-
ing tbe marine fauna of Shetland, they have returned home only tbe more
convinced of tbe greatness of the field of research wbicb remains to be ex-
plored. Every square mile of tbe sea seems to have treasures to give up
unknown before, and tbe extent of tbe riches wbicb lie there — one, two,
three, four hundred fathoms deep — will perhaps never be known in our day.
Tbe extreme interest wbicb attaches to tbe Shetland sea is tbe circumstance
that it is tbe trysting-place of tbe northern and southern faunas. Tbe wave
influence of the Gulf Stream, infringing on tbe western coast, coaxes on
many a species of sunnier climes to extend its migration northwards ; while
tbe cold winds and waves wbicb issue from tbe Pole, and come drifting-
round tbe West Cape, account for tbe many Arctic forms wbicb, stunted in
size and numerically scarce, are yet able, in tbe equable temperature of tbe
abyss of tbe Shetland waters, to bold out against those southern influences
so detrimental to their constitutions.

Development of the Dye in Fishes. — Herr Schenk lately sent in a paper to
the Imperial Academy of Vienna, in wbicb be described tbe development of
tbe eye of tbe trout. He stated that tbe lens is developed from tbe external
germinal lamella, and that tbe retina is produced from tbe thick inner wall
of tbe ocular vesicle, the thin inner wall contributing to tbe formation of tbe
pigment layer of the choroid.

Embryology of Pelobates fuscus. — The development of F.fuscus , a tailless
amphibian, has been watched by M. Van Bambeke. Some of tbe author’s

490

POPULAR SCIENCE REVIEW.

conclusions have a special embryological interest. He has found that (as
pointed out by Quatrefages in other animals) the disappearance of the ger-
minal vesicle takes place independently of fecundation. The other points
are as follows : — 1. The ovarian ovum has no vitelline membrane ; 2. The
embryos adhere to one another on leaving the egg ; and 3. The ovum presents
a yei'minal fossa which is not an aperture, but which the author compares to
the micropyle. — Vide H Institut, August 28.

How to detect the Silkworm, Malady. — M. Pasteur’s method, which con-
sisted in selecting a number of worms, pounding them in a mortar, and then
submitting the mass to the microscope, was neither simple nor economical.
The method which M. Balbiani suggested recently seems a better one. When
in the chrysalis state, a very small portion of the projecting process which re-
present the future wing is snipped off with a pair of scissors, and is placed
under the microscope ; if now the larva be diseased, the peculiar pebrine
corpuscles can be distinctly seen. The advantage of M. Balbiani’s method is
that it does not involve the death or injury of the silkworm.

Reproduction of Limbs in the Axolotl. — The axolotls (specimens of which
may now be seen at the Zoological Gardens in Regent’s Park) have lately
formed the subject of experiments by M. Dumeril. M.Dumeril found that in
these animals, as in the newt, there is no regeneration of amputated limbs
unless the basilar segment (scapular or ilium) is left untouched by the knife.
M. Vulpian’s recent observations, recorded to the Societe Philomathique, also
prove the fact of regeneration. M. Vulpian finds that when a number of
axolotls are together, it not unfrequently happens that, from bites and other
injuries, portions of the young limbs are destroyed. The consequence of this
is not simply the reproduction of the part destroyed, but the formation of
even a greater number of parts than were normally present before the injury.
This, he says, is the reason why we so often find specimens of axolotls whose
fore-limbs have five or six digits, instead of four, and whose hind ones have
as many as six or seven extremities, instead of five.

INDEX

Acalephje in a Fossil State 97

Acari, Development of, in Potatoes 117

Acarns in the Pigeon 115

Acetic Acid, Detection of Free Sul-
phuric Acid in 92

Acetylene, Description of 318

Acidity, Blue Litmus-paper a Test for 9 1

Aconitine, Action of 104

Acoustic Sand-figures, their Appli-
cation to determine Velocity of

Sound, &c Ill

Adiantum Capillus-Junonis 450

Africa (South), Dinosaurian Rep-
tiles of. 96

African Discoveries. By P. P. Du

Chaillu 185

Agouti (The Crested) 349

Agriculture.. 79

Air (compressed), Action of, on the

Circulation and Respiration 331

Air-pump, the Accoucheur’s

„ Microscopist’s 226

Algae, Diagnosis of. 90

„ Distinction of Species 199

„ Growth of. By J. Braxton

Hicks 1

Alkalies, Pure Caustic, Preparation of 90
Alkaline Sulphides, Electrolysis of 319
Alloys (Japanese), their Nature and

Nomenclature 337

Alum Crystals, how to cover Flowers

with 321

Aluminium Bronze in Machinery ... 471

Amazon, Fishes of... 235

„ Valley 460

America, Glacial Period in 210

American Naturalist 440

Ammonites Transversarius, Zone of 462
Amphioxus lanceolatus, Develop-
ment of 237

Anaesthetic (New ?), Impurities of 455
Analysis (Qualitative), New Method 458
Anencephalic Monsters, Production

of. 101

Aniline Colours from Flesh 321

Animal Tissues, Formation of Cells

in 221

Annelids, Boring of 488

Aphyllostachys -451

Araliacise, Vascular System of 314

Archaeological Congress, Interna-
tional 323

Arithmetic Simplified 439

Armour Plates, Solid and Laminated 466
Arnott, N., Arithmetic Simplified... 439

Astronomical Heterodoxy 429

„ Society, Memoirs of 442

Astronomy 80, 196, 309,

„ French Academy’s Prize

for

„ Popular

Atmospheric Electricity

Attfield, J., Paraffin Lamps and

their Dangers

Australia, Bismuth in

„ Salmon in

Australian Timber Boring Insect,

Tomicus monographus

Baird, W., Freshwater Entomos-

traca

Banca, Tin Mines of

Barometer (Aneroid), Behaviour of
Barrett, W. F., on Sensitive Flames
Bate, Spence, the Date of Flint
Flakes of Devon and Cornwall...
Bees, Production of Male and

Worker

Belgian Bone Caves and Rev. W.

S. Symonds

Bile, Secretion of, increased by

Mercury

Birds, Movement of Flight in

Birds’ Nests, Artificial

,, and Plumage

Bismuth, Action of, on Phosphoric

Acid

,, in Australia

Bisulphide of Carbon in Coal Gas

Bituminous Gneiss, Deposit of.

Black Spine, Analysis for

Blanford, H., Report on the Cal-
cutta Cyclone

Blast Furnace

Blood, Action of Hydrosulphuric

Acid on

,, Coagulation of

„ Corpuscles of the Two-toed

Sloth

„ Crystals of, in Leukamia ...

„ Disks, Mammalian

„ Poisoning after Surgical

Operations

„ Quantity of Red Globules in

Blower (A Rotary)

Blowpipe Reaction of Manganese

and Chlorate of Potass

Boilers, Anticru station of

Bone- Caves of Belgium

Bones (a Book on)

Borneo, Nature of Earth eaten by

the People of

Boronatrocalcite, Composition of . . .
Botanical Congress (International)

441
190

198

307

475

167

336

353

349

42

323

442
154

169

236

211

468

350
114
488

202

336

348

322

472

306

473

331
470

350

332
487

219

220
336

458

473

460

74

31S

216

450

492

POPULAR SCIENCE REVIEW.

Botanical Diagnosis, Chemical Re-
agents in 201

„ Lectureship, St. Mary’s... 313

Botanists, Deceased 89

Botany 87, 199, 313, 448

,, at British Museum 451

„ of a Coal Mine. By W. Car-

ruthers 289

„ Professorship of, in Trinity

College, Dublin 201

Bothriocephalus latus, Development

of. 118

Bowerbank, J. S., Monograph of

British Spongiidse 76

Brande, Dr., Dictionary of Science,

Literature, and Art 299

Brass-rubbing, Photographs of. 229

Bromine and Iodine in same Solution 454
,, of Potassium, Action of... 468

Bromized Collodion Process 342

Brooke, C., Elements of Natural

Philosophy 434

Burning Well 461

Cafeic Acid, Chemical Delations

of 453

Calculi, Civiale’s Collection of 334

Calluna Atlantica, a New Species? 200

Camera (a New) 344

Canada, Gold Mines in 323

Cancer (Epithelial), Development

of, in Internal Organs 101

Caoutchouc, Diffusion of Grapes

through Ill

Capillary Action and Chemical De-
composition 320

Carbonic Acid, Amount of, in Air 203
„ and Hydrogen, Ab-

sorption of, by Melted Copper ... 207
Carbonic Oxide, Conversion of, into

Formic Acid 205

Carboniferous Coal of Russia 324

Carruthers, W., The Botany of a

Coal Mine 289

Cedars of Lebanon 87

Cereals, Strength of Stalks not de-
pendent on Silica 315

Cervical Bibs 331

Chambers, G. F., Descriptive As-
tronomy 190

„ Fitzroy’s Weather

Forecasts 258

„ How to Study

Meteorology 140

Channel Bridge, 99

„ Ferry 328

Chapman, John, Diarrhoea and

Cholera 72

Chatham Ballast-iron 338

Chemical Analysis of Variegated

Strata 205

„ Manures 205

,, Operations, the Calculus of 457
„ Philosophy 194

Chemical Reaction, Physics of. 344

Chemistry, 90, 202. 317, 453

„ (Modern) for Students... 73

„ Organic 192

Chilled Shot 213

Chinese Coalfields, Age of 98

„ Soap Seeds 89

Chlorine and Manganese 455

Cholera treated by Ice 72

Circulation, Influence of Respira-
tion on 223

„ and Respiration, the
Action of Compressed Air on ... 331

Cladonise, the Arctic 452

Coal, Discovery of, in South Aus-
tralia 104

„ Measures (Our), What they

Yield 215

„ Question (the Yorkshire) ... 323
Coalfields in St. Catherines, Brazil 463

„ (Chinese), Age of 98

Cobalt and Nickel, Atomic Weights

of. 458

,, in Solution, New Test for ... 202
Colchicia, Chemical Properties of..- 319
Colliery Explosions and the Baro-
meter 207

Collodio- Albumen Process 341

Colocasia esculenta, Spontaneous

Movement of 316

Colour-blindness, Cause of 220

Comet observed at Marseilles, pro-
bable Periodicity of 197

Comets and Meteors 447

Conchology, British 434

Concretions, Banded and Brecciated 463

Conic Sections 78

Conifer (A New) from Arctic

America 450

Constellation (The) Seasons 438

Cooke, M. C., A Fern Book for

. Everybody 433

Copper and Palladium, Separation of 203

„ Electro-deposit of 486

„ Nickel Alloy ;. 472

„ Ores (Grey) Roasting of, in

Hungary 104

„ Presence of, in the Animal

Organism 103

„ Smelting 471

Cornea in Reptiles, Structure of ... 117

,, Removal of Opacity of 332

Cowpox and Smallpox 467

Crater (The) Linne 445

Crookesite, a new Thallium Mineral 456

Crumlin Viaduct 99

Cryptoprocta ferox 487

Culley, R. S., Handbook of Practi-
cal Telegraphy 439

Cuttlefish, Brain of 222

Cybele Hibernica 87

Cycadoidia Yatesii 326

Cyclone, the Science of 306

INDEX.

493

Darwin, C., Origin of Species
Darwinian Theory and Heliconidse

Denudation, Varieties of

Desmid, Parasites of

Dew

Diaphragm Eyepiece

Diatomacese, Distribution of.

Digitaline, Poisonous Action of ...
Digitalis, Physiological Action of. . .

Dilleniacese, Leaves of

Dinosaurian Reptiles of South

Africa

Divers, Edward, on Filters

Dodo-like Birds of Mascarene Is-
lands

Dog, the Ara, and the Frog

Dredging Committee, Shetland

Drift Deposits, Classification of.

Dry-rot, a Cure for

Du Chaillu, P. P., Journey to Ash-

ango Land, &c.

Dynamical Transmission of Power

Dysentery, Hyposulphites in • ••

Earth, Deduction of Mean Figure of

„ Internal Heat of

„ and Moon in Collision

„ Nature of, Eaten by People

of Borneo •••

Echinoderms (Fossil) from Sinai...

Echinus Li vidus

Eclipse, Lunar, the late

„ Solar, of 1863

Ede, G., Management of Steel-
Electric Conductors, Elongation of

,, Guns

„ Loom

„ Telegraph

Electricity, Action of, in Noctiluca

„ and Photography

„ Dynamical Theory of

,, for Students

„ Machine for Increasing ...

Electro-deposition of Copper

Electro-magnetic Machines (the

New). By S. J. Mackie

Electro-Magnetism in Iron Smelting

Elements (the)

Engineering Topics, Essays on

Entomostraca. By W. Baird

Eozoon Canadense

Ergotine after Operations

Erica Carnea, Affinities of

Euplectella.

Eye in Fishes, Development of

„ State of, in Hemeralopia

Eyes, Tobacco-smoking injurious to
Fairbairn, W., Useful Information

for Engineers

Fat, Absorption of

Fecundation of the Floridese

Fern Book (A Popular)

Fevers (Intermittent) produced by
Vegetable Organisms

Field Naturalist’s Companion 435

Figuier, L., The Vegetable World . 188
,, World before the Deluge 193

Fiji Islands, Flora of. 87

Filtering (New) Apparatus 206

Filters. By E. Divers 33

Fire-clays, Constitution of 473

Fire-damp Indicator, Physics of ... 232
,, Prevention of Accidents from 217

Fishes of the Amazon 235

, , of the Family Gadidse, Struc-
ture of the Heart in 236

,, New 488

Flame, Passage of an Induction

Coil Spark through 94

Flames, Sensitive. By W. F. Barrett 1 54

Flint Cores from India 97

,, Flakes of Devon and Cornwall,

Date of. By Spence Bate 169

Flora, Cretaceous, of Belgium 463

Floridese, Fecundation of 89

Foraminifera (Fossil) of Austria ... 460
Forbes, D.,The Microscope in Geo-
logy 355

Fore-limb of Great Anteater 487

Formosa, Sulphur Springs of. 462

Fossil Botany 200

„ Echinoderms from Sinai 209

,, Mammals, Hungarian 462

„ Man in Rhine Valley 209

„ Myriapod, from Scotch Coal

Measures 208

„ Plants, Collection of 200

,, Plants of Bilin 450

Fossiliferous Deposits of New

South Wales 96

Fossils (British), Figures of 97

Frankland, E., Lecture Notes for

Chemical Students 73

French Mint, Manager of 456

Fripp, H., Recent Discoveries in

Insect Embryogeny 119

Fruit, Ripening, Proportions of

Acid and Sugar in 321

Fuel (A New) 335

Fungi, Development of, in Kid-
neys ••• 330

„ Process of Fertilization in .. . 201
Fungus (an Edible), from Tahiti ... 450

Gas Engine 212

,, of various Cities, Illuminating

Power of. 317

Gases in Plant Tissues 450

Generation, Spontaneous 237

Geology and Genesis, Twin Records

of Creation 194

,, and Palaeontology 95, 207, 322,

459

Glacial Period 210

„ ,, in America 210

Glacier (ancient) in the Pyrenees... 464
Glass, a Chemical Method for effec-
tually cleaning 32o

66

114

209

452

77

223

316

104

333

201

96

33

488

115

489

325

448

185

465

220

196

461

112

318

209

115

445

444

75

231

231

329

303

118

229

112

69

484

486

281

336

71

74

42

325

222

313

239

489

100

222

74

331

89

433

220

494

POPULAR SCIENCE REVIEW.

Glass, How to Drill 348

,, How to Silver 94

, , Eods, Action of, in liberating

Gases from Solution 483

Glauber’s Salt, Deportment of Solu-
tions of, on Deduction of Tem-
perature 94

Glycerine, How to know Pure 320

„ in Crystals 206

Gold, Artificial 473

„ Mines in Canada 323

Granites (Grey) of the Southern

Uplands, &c 211

Gray, Dr. J. E., Venus’s Flower-

basket (Euplectella) 239

Gregarine Parasites in Borlasia ... 351
Gun-cotton as Blasting Material ... 217

„ in Mining 336

Gunnery, Effect of Earth’s Botation

on 485

Gunpowder Magazines 465

„ Hew Form of. 92

Guns (Electric) 231

Gypsums and Dolomites, Formation

of 322

Halo, On the 113

Hardwicke, Dr. W., On Life Insu-
rance and Vital Statistics 271

Heart, Duality of 102

,, Movements of. 100

Heat, Cause of, in Sun, &c 196

„ Influence of, on Muscular

Contraction 469

,, the Science of 194

Heather, Newfoundland 88

Helix Pomatia, Circulation of 238

Helleborine and Helleboreine, Phy-
siological Action of 103

Hemiptera, Secreting Organs of. 116

Herschel, Sir J. F. W., Familiar
Lectures on Scientific Subjects ... 191
Hicks, J. Braxton, Growth of Algae 1

Hippuric Acid ? What is 334

Holland (Bev. E. W.), Geology of

Sinai 10

Hooker, Dr. J. D., on the Struggle
for Existence amongst Plants ... 131

„ Sir W., a Memorial of 450

Hospitals 305

Hot-air Engine 465

Human Body, Action of Curara

Poison on 222

„ Histology, Study of 333

Hungarian Oligocene Deposits 326

Hunt, B., “A Message from the

Stars” 37S

Hunter, Bev. Jno., on Conic Sections 7 8

Hurricanes of Indian Ocean 475

Hyaena Den in Carmarthenshire ... 463
Hydrocarbons, action of Potassium
on ••• 205

Hydrogen and Carbonic Acid, Ab-
sorption of, by Melted Copper ... 207

Hydrosulphuric Acid, Action of, on

Blood 331

Hydrozoa, Development of 238

Hyposulphites in Dysentery 220

Ice, Cholera treated by 72

Iceland 302

„ Plants of 315

Ice Machine, Cheap and Ingenious 232

Induction Coil 194

„ „ Spark, passage

through Flame 94

Inductive Currents, Production of. . . 485
Insect Embryogeny, Becent Dis-
coveries in. By H. Fripp 119

Insectivora, Osteology of 350

Insects, Muscular Force of 237

„ Nerves in 117

,, Palaeozoic, of Nova Scotia 461
Iodide of Silver, Contractions and

Dilations of 345

Iodine, Chloride of Silver in the

Estimation of 320

,, Detection of 93

,, Starch, Decolorisation of ... 456

Iridium from Blende 337

„ in Canada 335

Iron and Steel, Strength of, &c. ... 466

„ Composition of Specular 472

„ direct from the Ore 215

,, Smelting, Electro-Magnetism in 336
Irrigation, Effects of, with certain

Plants 79

Isolation, Laws of 198

Japanese Allots, their Nature and

Nomenclature 337

Jeffreys, J. G., British Conchology 434
Jordan, W. L., The Elements, &c. 71

Jupiter without his Satellites 447

„ without his Satellites. By

B. A. Proctor 248

Kangaroo, Organs of Parturition

. in 236

Kew Photo-Heliograph 444

Kidney, Structure of 101

Kidneys, Development of Fungi in 330

Labels for Beagent Bottles 206

Laboratory, The 204

Lamp, Telescopic 478

Lankester, E. Bay, on the Plan arise

of our Ponds and Streams 388

Lardner, D., Handbook of Astro-
nomy 307

Lardner, Dr., the “Electric Tele-
graph” 303

Larva (A Curious) 352

Latent Image 227

,, ,, Nature of 343-480

Lawson, H., Ventilation and Venti-
lators 401

Lead, Separation of, from Argen-
tiferous Lead Ore 217

Leaf, the Fall of. 449

I Leaf-beds of Hampshire 461

INDEX.

495

Leaves, Why they Pall. By M. T.

Masters

Lebanon, Cedars of

Lenina and Wolffia, Prond-cells of
Lenses, Detection of “ Tears” in...
Le Vaux, Twin Becords of Creation

Liebig’s Food for Infants

Life Insurance and Vital Statistics.

By Dr. W. Hardwicke

Lightning, Singular Effects of

Limbs of Axolotl, Beproduction of

Lime in Analysis

Limestone, Expansion when Burnt

Liver, Inflammation of

„ Structure of.

Locomotive (Fairlie’s) for Steep In-
clines

London University, Chemical Ex-
aminers

Longitude, Difference of, between

Newfoundland and Valencia

Lunar Committee, Labours of

„ Crater Alhazen

„ Crater, Disappearance of ...

„ Eclipse, the Late

„ Maps

Lymphatics, Arrangement of

Lymph Vessels, Origin of

Mackie, S. J., The New Electro-

Magnetic Machines

Madrepores of the Infra-Lias of

South Wales

Magic Cigar Tubes

Magnesium, Action of, on Neutral

Metallic Salts

,, Bods for Toxicological

Purposes

Magnetic Dip, Measurement of.

„ Needle in the Study of

Volcanic Districts

Man (Fossil) in Bhine Valley

Manures, Chemical

,, Nitrogen of, its Accumu-
lation in Soils

Mars (The Planet) in Jan. 1867.

By B. A. Proctor

Masters, M. T., Why the Leaves

Fall .

Mastodon, Entire Skeleton of

Maunder, S., Scientific and Literary

Treasury

Mechanical Engineers, Institute of
„ Science ...98, 212, 327

Mechanics of Flight

Medical Biography

Medicine 100, 218, 330,

Mesotherium, Osteology of

Metallurgic Operations, Crucibles

for

Metallurgy, Mineralogy, and Mining
215, 335,

Metals, Transparency of, at a Bright
Bed Heat

Metamorphic Bocks, Foliation of... 208

Meteoric Shower in Mexico 197

Meteorite (A New) 233

Meteorites, Classification of 474

„ Physics of. 113

Meteorlike Bodies near the Sun ... 447

Meteorology 474

„ how to Study. By G.

F. Chambers 140

Meteors and Comets 447

„ August 10th, 1867 441

,, f Spectrum of 446

Methyl, Silicates of. 456

Microscope, Collins’, New Class and

Demonstrating 477

Microscope, Frith’s Pocket 479

„ Improvement of 105

„ New Objects for 339

„ (the), in Geology, by

Dr. Forbes 355

Microscope (the Travelling) 225

Microscopic Objects, Handy Cabinet

for 106

Microscopic Objects, how to Photo-
graph. By E. T. Wilson 54

Microscopic Table adjustable 477

Microscopy 105, 223, 338, 477

Miller, W. A., Elements of Che-
mistry 192

Mineralogy, Bussian 472

Mines, Motive Power in 337

„ Telegraphic Communication

in 216

Mining, Gun-cotton in 336

Mounting Case, the Amateur’s 223

„ „ the Student’s 224

Muscle, Structure of 218

Muscular Fibre (striped), Develop-
ment of 334

Muscular Contraction, Cause of ... 335

„ „ by Heat 469

„ „ studied under

the Microscope

Muscular System of Birds and

Mammals 487

Mushrooms and Toadstools 430

Myriapod (Fossil), from Scotch

Coal Measures ..... 208

Myriapoda (new) 235

Narcotic, Wrightia antidysenterica 103
Natural History Transactions, Nor-
thumberland and Durham 308

Natural Philosophy (Golding

Bird’s) 434

Naval Architects, Institute of 327

Nave, J., Handybook to the Collec-
tion, &c., of Marine Algrn, Dia-
toms, Desmids, &c 435

Nerves in Insects 117

„ in Muscle, Termination of... 335

„ Pneumogastric 467

,, Secondary, Electro-motive
Powder of 467

369

87

199

233

194

468

271

475

490

455

486

467

219

100

317

199

445

443

197

445

442

221

102

281

98

109

90

90

346

459

209

205

79

22

369

95

78

99

464

329

437

466

459

217

104

471

348

496

POPULAR SCIENCE REVIEW.

Newfoundland Heather 88

New South Wales, Secondary Fos-

siliferons Deposits of. 96

Newt, Reproduction of the Limbs 117

Niobium, Compounds of 92

Nitrogen, Determination of, in Am-

moniacal Salts 204

Nitrogen of Manures in Soils, Ac-
cumulation of. 79

Nitroglycerine, How to Use 105

Noad, H. M., Induct orum or Induc-
tion Coil 194

Noad, M. D., Textbook of Elec-
tricity 69

Noctiluca, Action of Electricity on 118
Northumberland and Durham, Na-
tural History Transactions 308

Norton, A. T., Osteology for Stu-
dents 74

Obituary 332

(Ecistes, A New Species of ...: 351

Oil Wells in Baden 217

Oppert, E., Hospitals, Infirmaries,
and Dispensaries : their Con-

struction, Arrangement, and

Management 305

Optics, Recent Memoir on 484

Organic Analysis, New Method of 453

Origin of Species 66

Orion, Nebula of 448

Oscillariae, Movement of 453

Osteology of Insectivora 350

Osteomalacea, Cause of. 470

Oxalic Acid in the Negative Bath 341
Oxide of Tungsten, N ew Reactions of 2 1 7
Oxychloride of Magnesium, a New

Cement 455

Oxygen, Cheap Mode of Obtaining 453
„ Determination of, in Or-
ganic Analysis 203

Ozone, A Town Without 474

„ Density of 454

,, Determination of the Den-
sity of 345

Ozone, Development of, during the

present Year 345

Ozone, New Test for 476

„ Relation of, to Direction of

Wind 476

Paleozoic Insects of Nova Scotia 461
Palladium and Copper, Separation of 203

Palm, A Hybrid 313

Parabolic Governor 100

Paraffin Lamps and their Dangers.

By J. Attfield 167

Parasites of a Desmid 452

Pascal-Newton, Controversy 448

Pelobates fuscus, Embryology of... 489

Pendula (Brass), Expansion of. 447

Pergeze, Analysis of the Waters... 92

Perseberg Iron Mines 471

Petroleum as Steam Fuel 216

,, for Steam Engines 473

Petroleum, (New) Compound 203

,, Origin of 211, 325

,, Production of Steam by

Employment of 104

Phosphate of Lime Bed in North

Wales 324

Phosphates (Soluble) in Cotton-fibre

and Seeds 319

Phosphoric Acid, Action of Bismuth

on 202

Phosphorus, Luminosity of 485

Photographic Awards at Paris Ex-
hibition 481

„ Lens (another new ?) ... 107

,, Medals, Presentation of 109

„ Paper (a New) 108

,, Prize, Due de Luynes ... 340

„ Process, Claudet’s 108

„ Society 342

„ Transfers 479

Photographs, Hardness a Defect in 228

„ in Colours 341

„ in N atural Colours ... 108

„ of Brass-rubbing 229

„ of Fossil Plants 315

„ of Medical Men 437

„ of Sierra Nevada ... 460

„ Preservation of 341

,, Permanent 109

Photography 106, 227, 339, 479

,, and Electricity 229

„ and Navigation 110

„ at the Paris Exhibition 339

„ by Artificial Light 47 9

„ in London 342

„ Submarine 113

Photo-Engraving Process (New) ... 343

,, Heliograph, Kew 444

Photosphymograph 469

Physics 110, 230, 344, 483

,, of the Brain. By B. W.

. Richardson, M.D., F.R.S 415

Pig, Specific Relations of 115

Pine (the), Medical Products of ... 220
Planarise of our Ponds and Streams.

By E. Ray Lankester 388

Planet, A New 447

Plant Beds of North Greenland ... 461

Plants (Fossil) ofBilin 453

,, „ of Wolfang 460

„ ,, Photographs of. 315

„ Hawaiian 449

,, Hybridization of 314

„ of Iceland 315

„ Illustration of Natural Se-
lection in 316

„ No New Genera of, in 1900 449

,, Starchy Matter of 89

„ Struggle for Existence

amongst. By Dr. J. D. Hooker.. 131

Plant-tissues, Gases in 450

Plates, Long-kept 343

Plesiosaurus, New Species of 208

INDEX.

497

Polarising Photometer, New

Pompeii, Shells in Ruins of

Pond-Stick (An Ingenious)

Popular Botany

„ Science, par excellence ...
Portrait Lens (New), Dallmeyers...
Potassium, Action of, on Hydro-
carbon

Potato, History of

Poultice, Useful Form of

Pozzolana

Prehistoric Settlements

Proctor, R. A., Guide to the Stars
,, Jupiter without his

Satellites

,, The Planet Mars in

January 1867

Prussia, Metal Manufacture of

Pseudomorphine, Isolation of

Ptolemy and Copernicus. By A

Wrangler

Purpurine, Formula for

Quinine, How to test the Purity of
Race, Influence of Development in

the Production of

Railway, Mont Cenis

Rainfall, July 16

Ray Society, Future Publications...

Refraction (Crystalline)

Reliquse Aquetanicse

Resorcine, Synthesis of.

Respiration, Influence of, on the

Circulation

Retina of Mammalia, Distribution

of Rods and Cones in

Reviews of Books 66, 185, 299,

Richardson, B. W., Physics of the

Brain

Richardson, Dr. Thomas, Death of

Rifled Small Arms

Rifles, Magnetic Polarity of.

Rocks Distribution of Life of

,, of North Devon and Somerset
„ (Metamorphic), Foliation of
Rooms, How to equalize the Tem-
perature of

Rotifer (A New)

Russia, Carboniferous Coal of

Saeety Vaeves

Salamander, Spotted, Poison of ...

Salmon in Australia

Sandstones (Local)

Santorih: a Volcanie Crater

,, Volcanic Disturbances...

Sap-currents, Nature of

Saturn, The Dusky-ring of

Scapula and Ilium, Homological

Relations of

Science, Dictionary of.

„ of the Weather

„ Treasury of.

Scientific Summary ... 79, 196, 309,

Seeds, Medicago Americana, Vitality

of 200

Seeds, Menispermaceous, Examina-
tion of 201

Sempervivum (a new) from the

Salvage Islands 201

Senecio, a new South African 451

Sensitive Plant, Contractions of ... 449

Serpents, Liguatulse of 118

Shells in the Ruins of Pompeii ... 462
Shepherd, C. W., North-west Pen-
insula of Iceland 302

Ships, Corrosion of 105

Shooting Stars, Cometary Theory of 198

Silkworm Disease 340

„ „ One of the Causes

of 237

„ Malady, How to Detect... 490

Silkworms (Diseased), Corpuscles

found in 315

Silurians (Upper and Lower), Rela-
tions of 463

Silver, Chloride of, in the Estima-
tion of Iodine 320

Silver, Ensuring Purity of 216

,, Hardness of 105

Sinai, Geology of. By Rev. E. W.

Holland 10

Skin, Absorption by 331

,, Clinical Lectures on Diseases

of 440

Sloth (the Two-toed), Blood Cor-
puscles of 350

Smallpox and Cowpox 467

Smith, W. G., Mushrooms and Toad-
stools 430

Smith’s New Growing Slide 106

Snow Ploughs, 213

Soap-bubble, Physics of a 485

,, Seeds, Chinese 89

Solar Eclipse of 1863 444

„ Spectrum 196

„ Spots 196

,, ,, Faye’s Theory of. 197

Solids, Flow of 330

„ under Pressure, Movement of 346

Something Sensational 110

Sound, Optical Analysis of 233

„ the Science of 428

Spectroscope, a Stellar 441

Spectroscopic Examination of the

Flames of Stromboli 460

Spectrum (A “ Standard”) 344

„ of Meteors 446

Spirifer Cuspidalis, Perforations in 324

Sponge (a rare) 115

Sponges, Animal Nature of 352

„ British 76

Stamens (Barren), Functions of ... 200

Starchy Matter of Plants 89

Stars, Aqueous Vapour in 445

„ Change of Focus in observing 447

484

462

226

188

191

229

205

88

334

336

212

438

248

22

216

333

429

203

458

235

213

474

488

347

440

93

223

218

428

415

458

465

231

95

97

208

114

234

324

214

470

353

326

436

459

202

442

102

299

439

78

441

498

POPULAR SCIENCE REVIEW.

Stars, (The), “A Message from.”

By B. Hunt

Steam-Engine, How to Make it ...

„ Hollers

Steel Armour Plates

„ Bridge

,, Casting under Pressure

, , Management of . . .

Stewart, B., Treatise on Heat

Stomata of Leaves, Punctions of ...
Strata (Variegated), Chemical Ana-
lysis of

Stratum (peculiar) in Arbroath

Cemetery

Street Dust a Poison

Strychnine, its separation from

Morphine

Sulphuric Acid, Manufacture of ...
Sulphurous Acid, Economisation of

Sulphur Springs of Formosa

Sun-painting in Oil Colours

Supersaturation, Means of Utilising

the Phenomena of

Swan’s Carbon Process

Syphon for the Laboratory

Taenia echinococcus, Hearing the

Tannin Process

Telegraphic Communication in

Mines

Telegraphic Thermometer

Telegraphy, New Form of.

„ (Practical), Handbook of
Telescopic Object-glasses, Means of
Weakening the Intensity of Sun’s

Hays at Focus of

Temperature, Changes of, produced

by mixing different Liquids

Temperature, Periodical Variations

of

Thermometers, Alteration of the

Freezing-point in

Thermometers, Standard

Thorina in Euxenite

Timbs, J., Year-Book of Facts,

Science, and Art (1867)

Tinctures, Preparation of

Tin Mines of Banca

Tobacco-smoking injurious to Eyes
Tomicus monographus, Timber-
boring Insect of Australia

Trachea, Inflammation of

Transparency of Air, Measuring of

Tuberculosis, New Theory of

Turret Ships

Tyndall, J., on Sound

Type-writing Machine

END

Urine, Crystalline Fatty Matter in 91
Vaixisneria, Moving Corpuscles of 448

Vapour Density 234

V ega, newly-discovered Comes of. . . . 443
Ventilation and Ventilators. By

H. Lawson 401

Venus’s Flower-Basket (Euplectella)

By Dr. J. E. Gray 239

Volcanic Eruptions near Portugal... 460

Volcano (New) in South Seas 322

Voltaic Piles, Improvements in 484

Water, Determination of Organic

Impurities in 317

,, Estimation of Organic

Matter in 454

„ in Bronze Vase found at

Pompeii 322

„ Organic Matter in 91

,, Supply of London 464

Waters, Frozen Aerated 230

Waterwitch, H.M.S 98

Weather Forecasts (Fitzroy). By

Gr. F. Chambers 258

,, Science 439

Wells, W. C., An Essay on Dew... 77

Whale, Anatomy of 488

White Ant 115

Wilson, E. T. How to Photograph

Microscopic Objects 54

Wind, New Instrument for Register-
ing Speed and Pressure of 110

Wine and Wine Sickness 93

Wire-spring Clip 223

Woodbury’s Printing Process 106

Wood Fibre in Paper, a Test for ... 204

World before the Deluge 193

Wrightia Antidysenterica, a new

Narcotic 103

Wurtz, Dr. A. C., Chemical Philo-
sophy 194

Xiphosura, Some Points in the

Structure of 96

Year Book of Facts, Science, and

Art 194

Yorkshire Coal Question 323

Yttria, a Mineral of, in the Alps.. 218
Zambesi, Silicified Vegetable Re-
mains from 315

Zinc, Manufacture of 471

„ the Reducing Action of 204

Zoology and Comparative Anatomy

114, 234, 349, 487

Zoophytes, How to Observe the
Reproduction of 352

VOL. VI.

378

438

213

329

99

214

75

194

88

205

463

457

206

454

471

462

227

112

109

453

116

228

216

486

230

439

111

230

346

347

234

205

] 94

203

323

222

349

468

486

467

214

428

329

OF

LONDON: PRINTED BY SPOTTISWOODE AND CO., NEW-STREET SQUARE

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