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SCIENCE-GOSSIP. 193
A GARDEN
POND.
By J. LEONARD MONK.
HERE are many points wrapt in doubt and
mystery connected with the aquatic life of
our freshwater tarns and rivers. As instances, we
may cite such cases as the necessity of better
observation of those small worm-like animals, the
Gasterotricha, little understood as yet; the dis-
covery of the males of some species of Rotifers;
and better knowledge of the aquatic caterpillars
of certain moths, ‘‘china marks,” etc. There is un-
doubtedly much more to be learnt of the develop-
ment and life history of aquatic insects by a careful
study of them in their natural surroundings. Even
to willing workers, however, in this field of research
it is often only on special occasions they are able
to pursue their investigations, especially if they
should find themselves time-hampered, unfortunate
town-workers, as is the case with the writer.
To overcome these difficulties, however, I re-
This arrangement, both for economy and result,
in my estimation, after having given both a fair
trial, far surpasses the ordinary glass aquarium.
The advantages claimed forit are the following :—
A maximum of surface is exposed to the atmo-
sphere, ensuring the freshness of the water and a
certain amount of natural food-supply for such
animals as frogs and newts, which feed on living
insects, worms, etc.; also the natural succession
of life takes place month by month. A good supply
of aquatic weed should be established on a gravel
bottom, to prevent stagnation of waste organic
matter, as it is well to change the water as rarely
as possible, for the retention of microscopic life. I
have not changed the water in my aquarium for the
last eighteen months, but it still remains perfectly
fresh. A small quantity has, however, been added
from time to time to supply loss by evaporation
CONSTRUCTION OF A GARDEN POND.
A. Sloping zinc border. 8B. Outlet cavity. c. Layer of fine cement. D. Layer of rough cement. ©. Layer of bricks,
r, Inlet pipe. G. Outlet pipe. H. Stodper.
solved to try an experiment which has worked
most satisfactorily, bearing good results. It is
therefore the object in this article to give a short
description of the method used, that others may
also share the pleasure and instruction afforded
by it.
The plan consisted in making a small garden
pond, of which the illustration gives a sectional
view. I have found the dimensions 4 feet in dia-
meter by about 1 foot 6 inches in depth quite large
enough for the purpose. An outlet pipe leads into
a cavity loosely filled with rubble, to allow the
water to drain into the earth. On the other side a
feed pipe is fixed, which can be used with the aid
of an indiarubber tubing connection, if there is not
a convenient water-supply. The bordering zinc
should be well tarred and bent over the water at
about the angle indicated, which effectually pre-
vents the escape of animals with straying pro-
pensities.
DECEMBER 1901.—No. 91, Vou. VIII.
The most suitable and hardy plants I have found
to be frogbit, Anacharis, and Potamogeton. Other
species may, of course, be substituted according to
taste and demands.
The stock of animal life to be introduced will
depend on the direction in which one’s interests
are chiefly engaged. My special hobby has more
particularly been the Amphibia, which readily
make themselves at home; so completely, in
fact, that I have had the satisfaction of seeing
many of them undertake family matters. Chief
among these important events was the pairing and
successful oviposition by some Bombinator pachypus
(fire-bellied toads), which for two years previously
had been kept in a glass aquarium without pair-
ing. A few of this brood are still living, having
successfully passed their critical juvenile stages.
For the student wishing to follow the develop-
ment of the common frog, no better medium could
be devised. I was less fortunate with Pelobates
Published November 25th, 1901.
194
fuscus (the burrowing toad), as they burrowed out
of sight.
The larvae of the three British newts, Molge
cristata, M. vulgaris,and M. palmata, are all easily
reared, and I have now under observation a brood
of MW. alpestris (the Alpine newt). I regret I was
not successful in obtaining any results from the
recently described MW. italica, discovered last year
by Count M. Peracca in the South of Italy, a few
of which I was fortunate enough to obtain through
the kindness of my friend Mr. Boulenger. One
method of observing these animals is to suddenly
turn a light on at night, when very often some of
them can be seen taking a nocturnal stroll round
the sides.
An important consideration in striking the
balance of the pond life is to have a good repre-
sentation of mollusca. The species I have found
to thrive best are the three common forms:
Paludin avivipara, Limnea stagnalis, and L. peregra.
The several species of ZVanorbis do not seem to
prosper.
The freshwater musse] (Anodonta) is handy to
keep for dissection, as it is easily kept and will
multiply rapidly. On various excursions taken with
a Natural History Society I have invariably bottled
SCIENCE-GOSSTIP.
a little aquatic weed or moss and placed it im
the pond on returning home. ‘The result is a fine
selection of microscopic life, a list of which would
cover most of the common forms. The ova of
various beetles and insects develop unexpectedly
and furnish hours of serious study. By this means
IT have just been following with much interest the
development of Cheronomons and the pond skater
(Gerris), with the aid of Miall’s work on the
‘Natural History of Aquatic Insects.”
With regard to Gerris, by the way, I am able to
confirm De Geers’s statement that it captures.
and devours living prey, which Miall rather dis-
credits, as I have actually seen this animal pounce
upon and demolish a small fly that had settled on
the water.
The above notes have been given merely as
examples of the advantage of having material
always at hand for any spare hour which may
thus be pleasantly and _ profitably spent. I
hope on some future occasion to give a more:
detailed result of observation and work done in
this way.
Blenheim Villa,
61 Clova Road,
Forest Gate, E.
NATURE NOTES IN SOUTH AFRICA.
By MaAgor H. A. Cummins, C.M.G., R.AM.C.
URING my stay in South Africa I endea-
voured to make a few notes on the natural
history of the district through which I passed, and
other matters of interest.
In winter the air is cold and invigorating, and,
when travelling over the extensive veldt, hares
frequently bound from the long grass, and some-
times herds of buck are to be seen. The veldt
cat and ant-eater make the ground dangerous to
horses, undermining it by burrows. Large holes
are to be seen in the ant-hills by which the veldt
is usually dotted. They are dug by the ant-eater
in its search for food.
The undulating country from Bloemfontein to
Pretoria is pleasant for travelling. It is inter-
sected here and there by rivers, which are crossed
by drifts or fords for waggons, not by bridges.
IT imagine that if the Boers could have procured
rolling stock for railways capable of crossing the
drifts like ox waggons they would have done so,
as they seem to have an intolerable dislike to
bridges. Excepting for the railways, bridges are
practically absent for cart traffic. The process of
crossing one of these drifts with a heavily laden
waggon is by no means easy. ‘The cutting to the
river bed is generally a steep gradient, and the
brake has to be put on at the right time, otherwise
the waggon or team, perhaps both, suffer -con-
siderably by over-running of the waggon. Ascend-
_ ing the other side is usually very difficult, as in
wet weather the path is covered by thick mud,
which prevents the draught animals taking a foot-
hold, and at the same time clogs the wheels. In
dry weather thick dust takes the place of the mud
and is nearly as obstructive. If the river is at all
flooded a waggon is in danger of upsetting or of
being washed away as it bumps from one boulder
to another, while several of the oxen may be out
of their depth and compelled to swim.
Oxen are strange animals to manage: they travel
best at night, feeding only during the day. During
the forced marches many succumbed to overwork,
as they had to travel nearly all day and during
part of the night. When an ox becomes sick or
weary he lies down and has to be loosed from the
yoke and left behind. If he is not very ill he
soon regains his feet, and commences to graze.
He will then probably be brought on by a later
wageon with a deficient team. If not, he dies or
is shot. Mules travel until they are quite worn
out. They sometimes drop dead in harness. A
mule would be getting into delicate health if he
could not accumulate suflicient energy to kick a
Cape boy when there was opportunity. These
SCIENCE-GOSSIP. 195
animals will eat wood, gnawing the disselboom, or
pole of a waggon, until it becomes too thin to be
of use. Of course, the conditions I have men-
tioned were only caused by the most urgent neces-
sity. The railway line, bridges, and culverts were
often blown to pieces, but still supphes and hos-
pitals had to come to the front.
As a rule waggons can proceed across country
regardless of roads, except here and there where
boulders occur, or in cultivated tracts. Once the
soil is turned up the surface is very soft, such as
in ‘‘mealie patches,” or where Kaffir corn is grown.
The whole country appears to be intersected with
barbed wire fencing. If this has been put up to
keep off lions, it has been most effective.
Trees are scarce unless cultivated near farms or
in towns, where they grow to a large size. At
Wanderboom, near Pretoria, there is an immense
fig-tree, resembling the banyan tree of India,
except that it does not throw out secondary roots
from its branches. This tree, I estimate, covers
an area of 5,000 square feet.
The common house-flies were a terrible pest at
Bloemfontein and The Glen. They swarmed on
food and irritated the patients in hospital, unless
kept away by mosquito-curtains or fans. ‘To some
extent we got rid of them from the tents by driving
them out at sunset and closing the tent doors,
when they settled outside and were in great part
killed by the night frost. Small collections of
rubbish will rapidly generate enormous numbers of
flies in a hot climate. In Pretoria I tested the
time required for the egys of the house-fly and
bluebottle-fly to produce the imagines, and I found
the period to be under a week.
Flies doubtless act as potent carriers of disease.
Bred in garbage, they become soiled in their
primary environment. In their after-existence, by
frequenting contaminated areas, diseased men and
lower animals, and subsequently alighting on those
in possession of health, they spread infection. To
counteract this, and for other reasons, I instituted
a method of pouring all discharges from diseased
subjects into a boilins solution ; no flies approached
the apparatus, as it was free from odour and gave
off great heat. The arrangement produced an
absolute holocaust of the lower forms of life; in
fact, after two minutes, life of all kinds became
extinct. This system, I have reason to believe, is
now used in hospitals in many parts of South
Africa, destroying in that country inestimable
numbers of those minute specks of livine matter,
which the inscrutable law of the universe has
appointed to perform the function of indiscriminate
destruction of human and other life.(')
Bites from what was locally called the tarantula
—a black hairy spider—were not uncommon, and
scorpion bites sometimes occurred. I saw two
men suffering from small abscesses, each contain-
(1) Brit. Med. Journal, April 20th, 1901, p. 954.
ing a larva about half an inch long by a quarter of
an inch thick. I believed them to be the larvae of
the Oestrus livingstonii. The larves on removal
were alive, and the abscesses then gave no further
trouble. Reference is made to similar larvae in
Cobbold’s “Human Parasites,’ an original larva
taken from Dr. Livingstone in South Africa was
said to be in the Hunterian Museum. By the
kindness of one of the curators I was enabled to
see this specimen, which I believe was identical
in species with those I have described, although a
little smaller. But this was probably due to
shrinkage caused by the preserving medium.
Rats were a great nuisance, occasionally gnaw-
ing the hair of persons during sleep. Snakes were
few in my experience ; but I found one under the
blanket on which a man had been sleeping.
The ordinary body lice (Pediculus corporis) were
frequent in the clothes of soldiers. It is difficult
to say how they originated. Residents in the
country maintain that the lice eggs are in the
veldt and in waggons. I never observed any of
the ordinary head lice (Pediculus capitis); but
from wherever the body lice came, they amounted
to a perfect scourge. When men were admitted
to hospital their clothing was put in store. If
infected, as was often the case, as soon as the
clothes were cold all the lice in the garments
would come to the surface. At this time they
could be easily destroyed, but they left their eggs
in the innermost folds and creases of the garments
so well protected that even boiling was of doubtful
utility in destroying them, disintegration of the
garments usually preceding that of the eggs.
Locusts came in swarms, and if they were as
frequent in other parts of the country as they were
in the portion through which we marched, they must
indeed be.very numerous in South Africa. I had
an. idea that they followed our food convoys; but
if they looked for spare biscuits at Paardeberg
they were disappointed. One comfort, at all
events, is, that a method of destroying them by
infecting some individuals with a species of Zmpusa
fungus has been introduced, by which they are
rapidly killed. The living ones consume those
dead of the fungus disease, and it is thus spread
indefinitely.
Ant-hills are very common on the veldt. They
form mounds from about two feet to four feet in
height, the diameter of the base being some four
or five feet. As far as I could see, they are com-
posed of earth mixed with some secretion from the
ants. In consistence they are extremely hard, but
the wheel of a heavily laden waggon cuts through
them. I tried to dissect one, and worked with a
pickaxe and spade for nearly an hour, but did not
get to the foundation, which appears to be deep in
the ground. The interior is excavated by tunnels
occupied by many old and young ants, with astore
of grass stems cut into portions about half an inch
long. The young ants are etiolated, while the old
H 2
196 SCIENCE. GOSSIP.
ones are of a reddish-brown colour, and possess
strong mandibles. Ant-hills were very useful to
our soldiers as shelters in the battles. The natives
grind the hills into powder, and, mixing them with
glue made from skins, use them for floors for huts.
The material sets hard like cement. Itis also used
for making tennis grounds. The Boers frequently
whitewashed ant-hills on the veldt to mark the
ranges for their guns.
The spruits in Pretoria provided a habitat for
land crabs. ‘These animals varied in size from a
couple of inches to four or five inches across the
shell. They dug holes under the footway, causing
considerable damage to the earth above, in conse-
quence of which the tunnels often collapsed after
rain.
There is one point which is perhaps worth
notice, and that is the method adopted by the
Kaffirs for smoking “gunja.” They soften the
ground with water, and bury in it a portion of a
sjambok lash. The lash is pulled through, leaving
a subterranean passage: at one end of this passage
the “ gunja” anda live coal are placed, at the other
end of the passage the mouth is applied. Having
previously filled the mouth with water, the smoke
is drawn into the mouth. The water is then
ejected and the smoke exhaled as in ordinary
smoking of tobacco.
The possibilities for scientific investigation in
South Africa must not be judged from the fore-
going notes. They were made often under great
difficulties, and cannot be called more than passing
observations, more serious occupation generally
commanding one’s attention. Still, they may be of
interest to some readers, and form for myself
a reminiscence of a very trying period.
29 Nightingale Place, Woolwich.
10th November, 1901.
AN INTRODUCTION TO” BRITISH -SPLDERS:
By FRANK PERcY SMITH.
(Continued from page 174.)
GENUS BATHYPHANTES MENGE.
ers genus may be distinguished from the six
preceding genera by the metatarsi of the first
pair of legs being as long as the tibiae. The femora
of the first and second pairs are usually each furnished
with a spine, but there are no metatarsal spines. The
eyes are arranged in a compact group, the distances
between those of the posterior row being less than the
diameter of the eyes. The posterior row is almost
or quite straight, and the anterior centrals are much
smaller than the laterals.
Bathyphantes variegatus Bl.
variegata in ** Spiders of Dorset.”’)
Length. Male 2 mm., female larger.
The most tangible characteristics are figured. It
is a rare spider.
(Linyphia
Bathyphantes eonecolor Wid. (7Zheridion
Jilipes Bi.)
Length. Male 2.5 mm., female slightly larger.
The vulva and palpal organs, which are figured,
are very typical. This species is not rare, and is
widely distributed.
Bathyphantes approximatus Cb. (Lzzy-
phia approximata in ‘‘ Spiders of Dorset.’’)
Length. Male 2.7 mm., female slightly larger.
Cephalo-thorax dull yellowish-brown, often with
some indistinct markings. Palpus of male short.
Digital joint with palpal organs very large, almost
equalling in length the rest of the palpus.
The palpal organs have, in common with those of
several allied spiders, a circularly curved spine at
their extremity. Apparently rare.
Bathyphantes nigrinus Westr. (Linyphia
pulla Bl.)
Length. Male 3 mm., female 3.5 mm.
The palpal organs have a coiled spine at their ex-
tremity, but they are considerably smaller than in
B. approximatas. The vulva is figured. Not rare.
Bathyphantes setiger, F.O.P. Cb.
Length. Male 2 mm.
This species may be at once recognised by the
entire absence of femoral spines.
Bathyphantes pullatus Cb. © (Lzuyphia
pullata in ‘ Spiders of Dorset.”)
Length. Male 2.5 mni.
Very closely allied to B. nigrinus, but lacks the
coiled spine at the extremity of the palpal organs.
Rare.
Bathyphantes gracilis Bl. (Lényphia gracilis
+L. circumspecta Bl.)
Length. Male 2 mm.
Abdomen almost white upon its upper surface, with
a series of dark transverse markings. The palpal
organs are figured. A very common species.
Bathyphantes parvulus Westr. (Liyphia
parvula in ‘‘ Spiders of Dorset.”’)
Length. Male 2.5 mm.
Closely allied to B. gracélis, but the abdomen is
unicolorous. Not common.
SCIENCE-GOSSIP. 197
Bathyphantes dorsalis Wid. (Lenyphia
claytoniae Bl.)
Length. Male 2.5 mm., female 3 mm.
The colouring of this common species is very
Sey?
Fic. 1. Lepthyphantes minutus Bl. Palpus and vulva
highly magnified.
variable. The female may be easily distinguished by
the form of the epigynum. Our Catalogue (96 pages) may be had post free on application.
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Scalpels, 1s. 3d. ; Label Lists of Birds’ Eggs, 2d., 3d., 6d.
Scissors, per pair, 2s. Setting Needles, 3d. and 6d. per box.
Coleopterist’s Collecting Bottle, with tube, rs. 6d., 1s. 8d.
Botanical Cases, japanned double tin, rs. 6d. , 28. 9d., 3s. 6d., 4s. 6d.
Botanical Paper, TES3Tds5, TSeAC sant Se od., & 2s. 2d. per quire. [7s. 6d.
Insect Cases, imitation mahogany, 2s. 6d. to IIs,
Cement for replacing antenne, 4d. per bottle.
Forceps for removing insects, 1s. 6d., 2s., 2s. 6d. per pair.
Cabinet Cork, 7 by 34, best quality, IS. 4d. per dozen sheets.
Pupa Diggers, in leather sheath, 1s. 9d. Insect Lens, ts. to 8s.
Glass Topped and Glass Bottomed Boxes, from 1s. per dozen.
Label Lists of British Butterflies, 2d.
Ditto Land and Fresh-Water Shells, 2d.
Egg Drills, 2d., 3d., 9d. ; Metal Blow Pipe, 4d. and 6d.
Our new Label List of British Macro- -Lepidoptera, with Latin and
English Names, 1s. 6d. Our new Catalogue of British Lepido-
ptera, every species numbered, ts. ; or on one side for Labels, 2s.
All articles enumerated are kept in stock, and can be sent immediately on receipt of order.
The “ DIXON” LAMP NET (invaluable for taking Moths off Street Lamps without climbing the lamp- -posts),
recently much improved, 8s. 6d.
CABINETS.
Special Show Room.
The following are the prices of a few of the smaller sizes ; for measurements and larger sizes see catalogue.
Minerals and Dried
Insect. Eggs. Plants, Fossils, &c.
AiDrawers: --s.-- 13s. 6d. 2s. od. tos. 6d.
6iDrawers ~ oss. 17s. 6d. 16s. 6d. 15s. od.
A LARGE STOCK OF INSECTS, BIRDS’
Minerals and Dried
Insect. Eggs. Plants, Fossils, &c.
S Drawers isie.cissi0 gee. Hneosens 30Ssn ecient 25S.
to Drawers. #5... AGSo Mrsisteiehs ernie SOS: bcceivestete 45S.
EGGS AND SKINS.
Birds, Mammals, &c., Preserved and Mounted by First-class Workmen true to Nature.
i= ~=CAII Books and Publications on Natura! History supplied.
386 STRAND, W.C.
(Five Doors from Charing Cross).
TO READERS ABROAD.
WANTED, Butterflies, Moths, Beetles, Flies and other
Insects ; also Scorpions, Spiders, &c., from Foreign Countries.
Full value remitted by return mail for specimens sent.
N.B.—Pack carefully so that they reach us undamaged.
Addresses also invited for Sale or Exchange.
HEYNE BRGS Dealers in Entomological Specimens,
ag Cabinets, Books, Apparatus, Pins, &c.
Fine Stock of European and Foreign Butterflies, Moths,
Beetles, and all other Families of Insects.
110 and 111 STRAND, LONDON, W.C.
Price Lists on application. Specimens submitted for selection.
BIRDS’ EGGS, SKINS, SHELLS,
INSECTS, APPARATUS,
and Requisites of all Kinds, sold, bought, and exchanged.
Fifty-page Price List on receipt of stamp. Estadlished 20 years.
CHARLES JEFFERYS, Naturalist,
TETBURY, Gloucestershire.
COLLECTIONS OF
MINERALS, SHELLS, FOSSILS, &e.,
For SALE. Also DUPLICATES cheap.
Apply to
EL M. HELE,
Warwick Lodge, KNOWLE, near BRISTOL.
Fy UL
A FILMLESS CINEMATOGRAPH
For taking and projecting life-size animated photographs with
greatest perfection to the extent of over 500 pictures.
Specially constructed for the Amateur or Professional.
Price £6 10s.
Negatives and Positive
SIMPLE and RELIABLE
MECHANISM. Plates, dgleseht
Subject Plates, 3/6.
6d. allowed for each Plate
returned unbroken.
With the KAMMATOGRAPH an ordinary dry glass plate is used
instead of cinematograph film. The method of developing KAM-
MATOGRAPH plates is exactly the same as with dry plates, thus
bringing cinematography within the reach of all.
SPEGIALITIES—Can be seen at the Manufacturers.
High-class Lantern and Jet, in travelling box £5
Do. , do., with patent electric arc lamp - - £6
PATENT RHEOSTAT, which takes from I2 > to 50 amperes at
110 volts without overheating. PRICE ON APPLICATION.
Also made for 200 and 250 voltage.
Write for Catalogue to the Manufacturers :—
L. KAMM & CO., Scientific Engineers,
Works—27f POWELL ST., GOSWELL RD., LONDON, E.C.
SCLENGEAGOS SEP:
Cg
DPF
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CONDUCTED BY F. SHILLINGTON SCALES, F.R.M.S.
ROYAL MICROSCOPICAL SOCIETY, October 16th.—
Wm. Carruthers, Hsq., F.R.8., President, in the
chair. Mr. C. Baker exhibited a portable micro-
scope on the model of the “ Diagnostic,” originally
designed for Major Ronald Ross’s investigation
of malaria. It is made of magnalium, an alloy
of manganese and aluminium, and weighs but
14 ounces. This firm also exhibited a microscope
intended for the examination of fractures and
etched surfaces of metals. It is provided with
vertical illuminator, and rack-and-pinion focussing
adjustment and levelling screws to the mechanical
stage now usual in this class of instrument.
Messrs. R. & J. Beck exhibited a portable model of
their “London” microscope, which is a very sub-
stantial instrument, and is, by the introduction of
several ingenious devices, made to pack with the
apparatus into a leather case 2} in. x 43 in. x 9} in.
Messrs. Beck also exhibited a centrifuge made to
run at a high speed by an electric current. The
Secretary announced that a letter had been re-
ceived from Sir Dighton Probyn intimating the
pleasure of the King to continue his patronage of
the Society. The President brought to the meet-
ing some specimens of the Mycetozoa, and gave a
brief account of the life history of this group of
organisms, The specimens belonged to a recently
described species, and had been named Badhamia
Joliicola, and he had brought for distribution
among the Fellows some leaves and grass on
which were spores. The President called attention
to the exhibits by Mr. C. L. Curties, consisting of a
number of mounted specimens of marine zoological
objects, accompanied by very full and interesting
descriptions. The President gave a résumé of a
paper by Miss A. Lorrain Smith on “ Fungi found
on Germinating Farm Seeds.” Miss Smith had
been assisting him in his work for the Royal Agri-
cultural Society in examining farm seeds in respect
to their germinating power. In the course of their
observations Miss Smith had found numerous
species of fungi on the germinating seeds—fourteen
species in all, of which five were new, and one
belonged to a new genus. The paper would be
printed in the Society’s journal. The Secretary
announced the receipt of part xiv. of Mr. Millett’s
report on the foraminifera of the Malay Archipelago,
which was taken as read. He also said that the
Hon. Thomas Kirkman had sent some of the fine
quills of the porcupine for distribution among the
Fellows, who would find them very useful in
mounting minute objects. Mr. C. Beck read a
letter from Mr. Gordon in reference to a portion of
his paper on the Abbé diffraction theory, and in
correction of the remarks therein made.
QUEKETT MICROSCOPICAL CLUB.—The 389th
ordinary meeting of the club and first of Session
1901-1902 was held on Friday evening, October
18th, at 20 Hanover Square, W., Mr. J. G. Walker,
209
F.S.A., Vice-President, in the chair. New members
were balloted for. The Secretary read a list of
books and periodicals added to the library since
the last meeting. The additions to the cabinet
were announced and acknowledged. These last
included some slides of plague bacillus found or
cultivated under various conditions, mounted and
presented by Mr. Pound, of the Stock Institute at
Brisbane. Mr. Scourfield read a paper by Mr. A.
Ashe on “Two-speed Fine Adjustments.” This
was a description of several forms of fine adjust-
ment, having two milled heads rotating on the
same axis, by which a medium or an extremely
slow movement could be obtained at will. Some
new forms of “ differential screw” movement were
employed to this end. The method recommended
for the Continental form of microscope had been
arrived at independently and put into practice by
Herr Reichert of Vienna. Another form which
was exhibited was employed, at the author’s
suggestion, by Messrs. Beck. Mr. Scourfield read
a paper on “Hydra and the Surface Film of
Water,” and showed, by means of an ingenious
model and by drawings on the blackboard, how
minute objects, though slightly heavier than water,
could remain in contact with its surface. ‘This
result was obtained by means of a waxy or water-
repellent substance coming into contact with the
surface film and forming a capillary depression.
The author pointed out how many aquatic creatures,
though undoubtedly heavier than water, could yet
remain at the surface without the aid of move-
ment or air-bubbles. The Hydra holds to the
surface by its basal disc, and the author had been
able to see a number of hyaline strands which
were apparently secreted from the disc. The
strands, though difficult to discern, were seen to
extend considerably, thus making a ‘capillary
depression” of comparatively large area. The
author believes that this stringy secretion, inter-
mixed as it is with globular and ovoid bodies, is
formed by the breaking-up of the ectodermal
cells of the basal disc. In the ensuing discussion
Mr. Karop described an analogous secretion in the
Gregarines. Mr. Morland gave instances of the un-
expected stresses the film of water will bear.
Mr. Rousselet read a paper on “ Vriarthra brachiata,
n. sp.” This was an account of a new species of
rotifer, and a specimen was exhibited under a
microscope. In the ensuing discussion, in reply to
a question by Mr. Scourfield, Mr. Rousselet said
that he had not met with an instance of a rotifer
making use of the surface film in the way that did
the Hydra and some Cladocera in fact, the sur-
face film was a death-trap to rotifers. Rotifers
provided with long spines, like Triarthra and many
others, were at a disadvantage in thatrespect. Mr.
A. A. Merlin’s paper ‘“‘ On the Spermatozoon of the
Rat ” was held over for the next meeting. Formal
proceedings then terminated. At the conversazione
many objects were exhibited, including a model to
show the support of the surface-film of water,
exhibited by Mr. Scourfield. This was a piece of
match weighted with a pin at one end sufficiently
to make the match sink ; the light end of the match
was smeared with vaseline. On bringing the match
from below to the surface of the water it hung
supported from the “surface film.” Messrs. R. &
J. Beck, Limited, exhibited a ‘‘ Pathological” micro-
scope with Mr. Ashe’s two-speed fine adjustment,
and Mr. R. T, Lewis exhibited a slide showing the
‘““Sense-organ on the palpus of male Anopheles.’
210
This was a curious projection on the extremity of
the palpus, free to move in all directions, even
inwards. It is not found on the common gnat, but
is seen on the palpi of ticks. Coloured drawings
were also shown. Mr. Rousselet exhibited a slide
of Lophopus erystallinus, beautifully mounted by
himself, and Mr. Earland exhibited a slide showing
trifurcate sponge spicules.
MANCHESTER MICROSCOPICAL SocrETy.—The
monthly meeting of this Society was held on
Thursday evening, November 7th, at the Grand
Hote], Manchester. Mr. Mark L. Sykes, F.R.M.S.,
read a paper on ‘Evolution in Butterfly Scales.”
Mr. Sykes said that he had selected for the purposes
of his communication some of the specimens illus-
trated in his paper on “ Natural Selection in the
Lepidoptera,” published in the “ Transactions” for
1897. as the illustrations would be available to the
members, and would enable them to see the close
resemblances which these butterflies bear to one
another. In whatever direction the mimicry may
tend, whether in simulation of inanimate objects
such as leaves or twigs or moss, for concealment
from their enemies on the one hand or to enable
them to secure their prey on the other, in mimicry
of conspicuously marked or highly coloured in-
edible by edible species, in resemblance between
two or more equally distasteful but entirely different
species, or whatever purpose the mimicry may
serve; it seems that the resemblance is in outward
appearance only. Although the similarity in
colour, pattern, and markings may be so close as
to be almost identical, microscopical examination
of the wing scales of these insects shows that the
details by which the likenesses are brought about
may be, and often are, widely different. The
specimens from which the examples were taken
fall under two groups of mimicry, that of Miiller
and that of Bates. The Miillerian form of mimicry
is that in which two or more highly coloured, con-
spicuously marked, or peculiarly shaped butterflies,
all inedible and distasteful to the insect-eating
animals, are so closely alike as to be easily mistaken
one for the other. ‘These by their similarity in ap-
pearance afford each other mutual protection by
dividing between them the total number destroyed
by the young Insectivora of each season in learning
what is and what is not good for food. ‘The
Batesian mimicry is that in which certain con-
spicuous and nauseous species that the young
birds, etc., quickly learn are distasteful, aresimulated
by others which are not nauseous, but which have
acquired the colour-markings of inedible forms and
are thereby protected. Amongst the former are
the Heliconinae, Danainae and Acraeinae, all of
which include amongst their members numbers of
highly-coloured species conspicuous for their
markings in red, yellow, black and blue, with
intermediate tints or shades, and which are easily
distinguished in their surroundings. In the latter
are included butterflies of nearly every sub-family,
and some of the diurnal moths, and both are found
nearly all over the world. Yet, on examining with
the microscope the scales of the wings of these
mimetic butterflies, it will be found that, so far
from the similarity in superficial appearance being
similarity in detail and pattern, there is a wide
diversity in scale structure and arrangement. ‘The
scales vary not only in numbers, but in size, colour,
and form, and this is the case even where one
inedible species mimics another. Mr. Harry Yates
exhibited under a number of microscopes tow-
SCIENCE-GOSSIP.
nettings from various localities, chiefly Naples,
Port Erin, and Stromness. ‘The results of these
gatherings, collectively termed plankton, he said
differed very much according to locality and time
of the year. The state of the weather may also
account for the presence of specially abundant
species. The young stages of nearly all forms of
marine life are to be found in floating condition,
at the mercy of tides and currents, thus spreading
the species over wide areas.
C. BAKER’S ENGINEERING MIcROSCOPE.—This
instrument (fig. 1) has been specially designed for
the examination and photography of metals (see fig.
2). It contains several distinctive characteristics.
As it is intended for the examination of opaque
ui Ere
hin, i D
Fic. 1. ENGINEERING MICROSCOPE,
objects exclusively, no means of substage illumina-
tion is provided, and even no stage aperture.
Opaque objects to be examined with moderate
powers can be illuminated in the ordinary way by
means of a bull’s-eye, a side reflector, or a leber-
kiihn, but with high powers a vertical illuminator
must be used. This is simply a collar placed above
the objective with a small hole at the side through
which a strong light from the lamp is directed, the
size of the hole being adjusted by means of a dia-
phragm. Within the collar is a disc of cover-glass
set at an angle of 45°, which without materially
SCIENCE-GOSSIP.
interfering with vision reflects the light down
through the objective to the object and back again
to the eye. In some illuminators of this type a
prism covering half the field of view takes the
place of the disc of cover-glass. The body-tube
has the usual coarse and fine adjustments ; but as
it is inconvenient to move it when once the adjust-
ments have been made, the stage is provided with
TROOSTITE IN A MATRIX
x 850.
Fig. 2. PHOTOGRAPHY OF METALS.
OF FERRITE AND MARTENSITE.
an independent rack-and-pinion focussing adjust-
ment, as well as with mechanical stage and level-
ling screws for the object under examination. The
eyepieces are of the R.M.S. No. 3 gauge. The
workmanship and finish of this microscope are of
the highest. class. The foot is of the solid tripod
form, the back leg of which might, however, with
advantage be extended a little more, with a view
to gain increased steadiness in the horizontal posi-
tion. The price of the stand alone is £16 16s.
NEw “DIAGNOSTIC” MICROSCOPE IN “ MAG-
NALIUM.’—In addition to the foregoing microscope,
Mr. Charles Baker has also submitted for our
inspection a ‘‘ Diagnostic” microscope (SCIENCE-
GOSssIP, vol. vi., p. 182) constructed almost entirely
of “magnalium,” an alloy of manganese and alu-
minium, and resembling the latter metal in appear-
ance. The total weight is only fourteen ounces. The
price of the microscope when in this alloy is £5 10s.
BECK’S PORTABLE ‘“ LONDON” MICROSCOPE.—
Messrs. Beck have recently added a portable model
to their list of London microscopes (see 8.-G.,
vol. vii., p. 184), in which the back leg of the base
slides in, whilst the side legs fold together, the
stage itself being removable. In other respects
the instrument is the same as the ordinary model,
fitted with draw-tube, coarse and fine adjustments,
also rack-and-pinion sub-stage, but with the
additional Bciveama ge of packing into a leather
case 93 x 45 x 24 inches in size. ‘The price of the
stand, ‘without OREO TES, eye-pieces, or condenser,
is £6 'Bs. The “ London ” microscope is now made
in a cheap vertical form, without joint for inclina-
tion or sub-stage, and with plain brass stage with
wheel diaphragm, but with graduated draw-tube.
spiral rack-and-pinion coarse adjustment, micro-
meter screw fine adjustment, and double mirror, for
the sum of £2 13s., complete in mahogany case.
BAUSCH AND LOMB MICROTOMES.—Messrs. the
Bausch and Lomb Optical Company have recently
issued a new catalogue of microtomes, and have
211
submitted to our notice several of the instruments
listed therein. The most important of these are
the Minot Automatic Rotary and Minot Automatic
Precision Microtomes, of elaborate construction,
and consequent high price, which are more espe-
cially designed for advanced work. The laboratory
microtomes of this firm are of equal excellence of
design and workmanship, if somewhat less elabo-
rate in form. In these the object to be cut. is
raised by a screw with a feed adjustable from two
to sixty micra, the adjustments being so arranged
that any desired cutting angle or length of stroke
can be had. The knife itself is carried on a
v-shaped block. A microtome of this description,
with feed operated by hand-lens, is listed at
£10 2s., complete with knife and holder. A smaller
microtome is of similar design, but the object is
raised by a micrometer screw witha pitch of 5mm.,
witha graduated head divided into a hundred parts;
so that each graduation has, therefore, a value of
5 micra, and there is no automatic feed. ‘This
microtome is specially designed for students, and
costs, with knife and holder, only £4 lls. 8d. A
very substantial table microtome, somewhat of the
Leitz type, costs £2 10s. Amongst new designs
may be mentioned a simple microtome for freezing
with carbon dioxide gas, which can be attached to
the gas cylinder.
MountinG WEB OF SprmpER.—I found no diffi-
culty in mounting spiders’ webs in balsam. I
painted a strip of varnish across the two ends of a
clean slide, and held this flat against the web; the
slide was covered with it, and the oblong torn from
the web was held in position by the varnish. I
added two or three strands of the big stays or cords
supporting the web from the tree, and then left
the whole to dry. A few days after I poured on
the centre a little balsam dissolved in chloroform,
then dropped a cover-glass on it, and left it to
dry. ‘The thinnest lines are visible, and the dirt
(soot) on them more so. The hawsers, as I call
them, show their multiple structure well. The
lines which compose the cross threads of the net
are smallest, but quite clear and simple. They
are as visible in balsam as flax fibre is, and there is
no tendency so far to dissolve—F. W. Payne,
Grove Park, SL.
R. & J. Beck’s NEw ;4-INCH OIL IMMERSION
OBJECTIVE.—Messrs. R. & J. Beck, Limited, have
sent for our inspection a new ;4-inch oil immersion
objective. The extra mag nifying power over a 35-
inch objective is of service in bacteriological and
malarial investigation, whilst the price is the same.
This lens is made with numerical apertures of 1:0
and 1°25, and sold at £4 and £5 respectively. We
have tested the first of these, and can speak favour-
ably of its performance; the corrections are excel-
lent and the working distance ample, whilst the
aperture is sufficient forthe requirements mentioned,
which do not need great aperture. We some-
times question if, in the reaction against objectives
of high initial magnification without corresponding
increases of aperture, we have not overlooked the
advantages that mere magnification will give us in
certain investigations—a magnification in excess, at
any rate, of the 75-inch immersion objectives that
are the highest ‘powers now generally asked for,
and to which special attention therefore has been
given by opticians. The working distance certainly
becomes a difficulty with higher powers, but it is
a mistake to suppose that an objective does not
212
deteriorate in its performance when used with a
high-power ocular to gain the needed magnifica-
tion.
C. BAKER'S NEW CATALOGUE.—Mr. Charles
Baker has sent us his latest catalogue, which is an
enlargement and revision of the previous issue.
The arrangement of the contents might with ad-
vantage be copied by other makers. The first
division contains particulars of microscopes, illu-
minating apparatus, mechanical accessories, and
apparatus for recording observations, all in due
order. The succeeding divisions are devoted to
apparatus for collecting, preparing, mounting, and
storing specimens; to apparatus for bacteriology.
blood examinations, and medical analysis ; and to
lists of microscopic slides, models, and specimens.
Notable features are the explanations and excep-
tional detail as to measurements in regard to each
entry in the catalogue. The very full list of objec-
tives includes those of Leitz, Reichert, and Zeiss,
as well as My. Baker’s own series, and is very con-
venient for reference. We observe, however, some
errors in the calculation of total magnifications
with eyepieces of stated powers with a tube-length
of 160 mm. The well-arranged list of stains,
mainly from the laboratory of Dr. G. Griibler, of
Leipzig, will be of service to all microscopists, the
list of mounting sundries being equally complete.
The pages devoted to mounted objects are con-
siderably extended, especially as regards the slide-
lending department (ante, pp. 153, 154), and we
note that the prices of individual slides have been
largely revised, in accordance, we understand,
with a suggestion made in these pages when the
previous edition of the catalogue was noticed.
ANSWERS TO CORRESPONDENTS.
F. A. H. (Epsom).—The particulars you give are
scarcely explicit enough to enable me to help you.
Can you give me an exact drawing—or, better still,
send the slide itself, that I may be sure to what it
is you allude.
[For further articles in this number on Micro-
scopical subjects, see pp. 197 and 200. |
MEETINGS OF MICROSCOPICAL SOCIETIES.
RoyAL MICROSCOPICAL SocIETY.—20. Hanover
Square, December 18th, 8 p.m.
QUEKETT MICROSCOPICAL CLUB.—20 Hanover
Square, December 6th, 7 p.m.; December 20th,
8 p.m. ;
MANCHESTER MICROSCOPICAL SOCIETY. — Grand
Hotel, Manchester, December 5th, 7 p.m. ; Mount-
ing Section, December 19th, 7 p.m.
SUNDERLAND MICROSCOPICAL SoctETy. — Sub-
scription Library, Sunderland, December 17th,
7.30 p.m.
EXTRACTS FROM POSTAL MICROSCOPICAL
SOCIETY’S NOTEBOOKS.
[Beyond necessary editorial revision these ex-
tracts are printed as written by the various
members.—Ep. Microscopy, §.-G.]
Fossil Polyzoa.—Figs. 1, 2, 3, and 4 represent
fossil Polyzoa from the Wenlock beds of the Upper
Silurian. Figs. 5, 6, 7, 8, and 9 represent fossil
Polyzoa from the Coal Shales (Scotland) of the
Carboniferous period. Allman’s definition of
Polyzoa is as follows :—‘ Alimentary canal sus-
SCIENCE-GOSSIP.
pended in a double-walled sac, from which it may
be partially protruded by a process of evagination,
and into which it may be again retracted by
invagination. Mantle surrounded by a crescent of
hollow ciliated tentacles. Animals always forming
composite colonies.” These polyzoa live in colonies
or ‘* polyzoaria.” Each polyzoarium consists of an
assemblage of distinct but similar zodids arising
by continuous gemmation from a single primordial
individual. They possess sexual organs and are
hermaphroditic. Polyzoa belong to a very ancient
race. They seem to have been present in great
numbers both in Silurian and Carboniferous beds.
Though one branch of the family, the Fenestella or
“Lace Corals,” appears to have died out with
the Carboniferous period, representatives of this
large as well as ancient family have existed in
more or less abundance throughout a great portion
of the Primary, Secondary, and Tertiary Periods,
and are, as we know, to be found in many parts of
the world at the present time. I have in my pos-
session upwards of sixty fossil species extending
over the four great geological periods. The fact
that this family has existed so long and varied,
FosstL PoLyZoa,.
comparatively speaking, so little, shows, to my
mind, how well it has been suited from the first to
its environment, and how well it has been able to
hold its own in the struggle for existence, whilst
many of its contemporaries in each of the four
great geological periods have become extinct. It
may be, however, that the environments have not .
differed sufficiently to produce any great change,
or that the organism is not sufficiently sensitive to
such change. See Darwin’s “ Origin of Species.”
(To be continued.)
SC/E NCE GOSSIP. me
ISTRONOMY,
M. i
CONDUCTED BY F. C. DENNETT.
Position at Noon.
1901 Rises. Sets. R.A. Dec.
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Sun... 1.. 7.45 am. .. 3.53 p.m. ..16.27.33 .. 2 S.
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31... 8 8am, .. 3.58 p.m. ..18.39.48 .. % Ss.
hises. Souths. Sels. Age at Noon.
Dec. him. hm. hm. Gsm.
Moon. 1 .. 10:35 pm... 4.36 am. .. 11.387am... 20 4.26
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Zila Les OMPiM ase 0-2) Pits. 2.401... ... LO) (90 7
31 .. 11.44 p.m... 4.49 am. ..10.5lam... 20 9.7
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Semi- R.A. Dec.
diameter. h.m.s. oO LL
Souths.
Dec. him.
Mercury.. WS 10!40°7 a.m: .. 2:77" ..15.19.23 ..16.47.26,5.
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2) 5.1028:9 am, .. 2:3! 2117.26.21 ..24.°2:53.8.
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VCRUS. oo Al og SHUAO™ foveal IPR OY 3.31 ..23.43.25 8.
Il .. 3.17°6 p.m. ..13°5/: ..20.35.34 ..2 3.04 8,
21 eo 4:O p.m. «Lord 202023) 3. 8S.
31 .. 3. 5:5 p.m. ..17°6!! . 21.42.35 Ss.
WPS 99 Bil og UBS Ws yo CHU Soren EE y/ Ss.
Jupiter .. 21 .. 1.248 p.m. ..15°0” ..19.22.21 ..22.21.328
Saturn .. 21 .. 1.13°8 pm... 7:0” ..19.11.23°..22.14.57
(OPOROS. oo DAL Goll GP Bid, Go als! Sealife We Il
IMGHOHRE oo Viv oa Os GR eon G5 eP! Ga Oe a5
Moon’s PHASES.
him.
9.49 p.m.
18 ., 8.35 p.m.
hm.
2.53 a.m.
25 .. 0.16 p.m.
CHGS iro 35 IDES G5
as QRS oo
New = Decker
JOU ch
In apogee on December 8th, at 2 p.m.; and in
perigee on 24th, at 3 a.m:
METEORS.
him. ©
Dec. 1tol4.. Geminids Radiant R.A. 7.12 Dec. 33 N.
_ 7 to 10 .. a Geminids a Ue gy PRINTS
» 22%t029.. Oanis Venaticids ,, = LOS BRIN
CONJUNCTIONS OF PLANETS WITH THE Moon.
ey ff
Dec. 4 Junot leas Planet 0.14 8.
Patan O) oaei5 Mercury} .. 10pm. .. a 1.23 S.
«als Bes Mars*}) ©... 8ia.m. on OBS
op 1B Saturn* 5 IMaT, —s5 » 44708:
of ed, G5 Jupiter* i PIN, o5 > 4.088.
Repl ree Venus* o dil Bai S65 5. Coo) Sh
co, Wl oo Junot HANS so ay OuliSENE
* Daylight. + Below English horizon.
OCCULTATIONS AND NEAR APPROACHES.
Angle Angle
Magni- Dis- From Re- Strom
Dec. Star. tude. appears. Vertex. appears. Vertex.
him. oC hem. 2.
14 .. B Capricorni -- 6.43 p.m... 9 .. Below horizon.
- 6.32 p.m. .. 309 ..
3
15 .. vy Aquarii re near approach.
3
18 .. A Piscium 5 oa B88 oo & Oi, oo Bey
DB 56 e Tauri FU oo Bu Do, .5 BO) 5, GM inn oo il
PR oo th gp 51 .. 4.28am. ., 142 .. near approach.
THE SUN seems to show slightly greater activity.
October 10th to 12th and October 28th to Novem-
ber Ist groups of spots were observed in the
Southern hemisphere. A fine spot with one or two
.
minute companions has also been visible crossing
the disc since November 14th, and was con-
spicuous on the 18th. There can be no doubt that
the minimum had been passed by that date. At
1 p.m. on December 22nd, when the sun enters the
sign Capricorn, winter is said to commence.
MERCURY is a morning star, rising in the south-
east more than an hour anda half before the sun
at the beginning of the month, but its position
grows daily worse. At noon on December 18th
Mercury is in conjunction with Uranus, passing 28’
south of the fainter planet.
VENUS reaches its greatest eastern elongation,
47°15’, at 10 a.m. on December 5th, but its great
southern declination is not favourable for good
observation.
MARS, JUPITER, and SATURN are too near the
sun for observation, otherwise the conjunction of
Mars with Saturn at 11 a.m. on December 14th,
Mars being 1°18’ south, and that of Mars with
Jupiter at 3 p.m. on the 17th, Mars being 52’ to
the south, would be interesting phenomena.
URANUS, being in conjunction with the Sun at
9 p.m. on the 9th, is placed in an impossible
position for observation.
NEPTUNE, coming into opposition at 2 p.m. on
December 22nd, is well situated for observation all
the month, retrograding some 5m, 35°3s. just west
of » Geminorum.
Nova 1901 PERSEI has proved to be even more
interesting than could have been anticipated. In-
formation has been received from the Lick
Observatory that the photographs of nebulous
matter amidst which the Nova is situated, taken
with the great Crossley mirror, show that four
nebulous condensations have a daily motion of
1-5 towards the south-east. Such are the deter-
minations of Professor Perrine. As was mentioned
in SCIENCE-GOSSIP, N.S., No: 88, p. 124, MM. Flam-
marion and Antoniadi, at Juvisy, in France, had
photographed what appeared to be a nebulous
aureola around the star, having a definite outline.
Mr. Alexander Smith, of Dalbeattie, and Professor
Max Wolf, of Heidelberg, both confirmed these
observers, and, moreover, all of them have come to
the conclusion that the effect has an optical, and
not an objective, origin. Indeed it has been found
that when the plate is exposed behind an object
glass, the star itself is photographed in the usual
manner. If the exposure has only lasted a short
time, there is an aureola formed around it which
gives the star very much the appearance of a sun-
spot, an umbra surrounded by a penumbra. If a
longer exposure is given, a second aureola makes its
appearance around the inner one; and if the ex-
posure is sufficiently prolonged, the inner aureola
becomes quite dense. ‘It was noted that the larger
aureola was a magnified representation of the
smaller, and when Wolf covered over a half of
his objective the appearance was found to be
present round one-half of a circle. The only
explanation at present is, that the star gives out
light to which the photographic plates are sensi-
tive, but of so different a wave-length to those
usually known that our object-glasses are not suffi-
ciently corrected for them. The reflector brings
them to the same focus as the other rays, because
its effects are due to reflection and not to refraction.
With M. Flammarion’s 63-inch portrait lens of
273-inch focus, half an hour’s exposure showed the
star with an image only ;1,-inch in diameter, the
aureola having an angular diameter of 2’. With
214
3h. 20m. exposure the larger aureola is brought out
with a diameter of some six minutes of the arc.
The brightness of the star is said to show much
less variation.
‘OBSERVATION WITHOUT INSTRUMENTS.” by
Arthur Mee, F.R.A.S. (82 pp., 6} in. x 4 in., with
frontispiece), is a useful brochure for those
who want to begin the study of the heavens
without instrumental aid. It may be obtained
from Messrs. George Philip & Sons, price 3d., or,
post free for an additional halfpenny, from its
author, Llanishen, Cardiff.
THE PARHELION mentioned on p. 182 of SCIENCE-
Gossip, No 90, ‘*was observed a little east of the
real sun, and equally above the horizon. Mock
LEEOs
BOLTON OEL:
SCRIVEN
RINGS or SATURN.
disc appeared red.
12.30 when the phenomenon was visible.”—( Rev.)
S. Arthur Brenan, Strand House, Cushendun, Co.
Antrim.
NOVEMBER LEONIDS.—Astronomers were again
disappointed with regard to the November leonids
in 1901. In many parts of the country cloudy
weather Prevaned still some were observed on
November 13th and 14th, though not in large
numbers. A considerable flight was seen from a
vessel off the east coast of America.
CHAPTERS FOR YOUNG ASTRONOMERS.
By FRANK O. DENNETT.,
(Continued from page 183.)
SATURN’S SYSTEM (concluded).
DURING the opposition of 1899 Mr. H. J. Towns-
hend, of Leeds, saw the Cassini division of the
rings passing apparently a little north of the
North Pole of the planet, although the portion
close to the pole was hidden by the shadow. In
1900 the division seemed to be approaching the
limb of the planet as if it would be tangential to
the North Pole. This is very much the appearance
shown in Mr. Bolton’s drawing from the “ Memoirs
of the British Astronomical Association,” repro-
duced by permission. In 1914 the visibility
should be looked for of the division south of the
Southern Pole.
The time of day was about
SCIENCE-GOSSIP.
The oldest known observation of Saturn was
made by the Chaldeans on a date answering to
March 1, B.c. 228, when the planet was a little
south of y Virginis. On February 21st, sixteen
minutes before midnight in the year A.D. 503, from
Athens, Saturn was observed to reappear from the
middle of the illuminated limb of the moon, after
occultation.
Whiston records that Dr. Samuel Clarke and his
father, observing with a 17-foot refractor, about
the year’ 1707 or 1708, saw a star between Saturn
and its ring. Dawes once observed a star of less
than eighth magnitude pass behind the outer
edge of “A,” but under unfavourable circum-
stances. Some time since, the discovery of a
ninth satellite of Saturn was announced on the
(from drawing bu S. Bolton.)
strength of some photographs, but the discovery
needs. further confirmation. [ts orbit was believed
to be far outside that of Japetus.
URANUS.
This giant world is some 30,875 miles in diameter,
so that fifty-nine globes the size of the world would
only equal it in bulk; yet set in the scale it would
need but fourteen times the weight of the earth to
balance it, so that, bulk for bulk, it is just a little
weightier ‘than Jupiter. * A weight dropped on its
surface would only fall thirteen feet in the second
instead of sixteen feet, as on the earth. It is readily
visible to the naked eye as a star of between five
and six magnitudes. It has an apparent angular
diameter of about 3’”: ‘7, so that any good telescope
of three inches aperture, or over, will detect that it
has a sensible disc; but it appears very “‘ woolly ”
and ill-defined unless an instrument of at least six
inches is employed.
With nine inches Buffham thought he could ob-
serve traces of bright patches, and Lassell was once
of opinion there might beaspot. Another observer
believed he could see belts. Miéidler thought he
saw, and measured, the ellipticity of the disc as
10-9, which, ,with the appearance of the spots,
seems to indicate that the rotation is almost from
north to south, and is at the same time rapid.
Sir W. Herschel thought that he had discovered
six satellites to Uranus, but only two of them
SCIENCE-GOSST/P.
appear to be real; two others were, however, dis-
covered by Lassell and Otto Struve in the autumn
of 1847. All four of them are beyond the reach
of the ordinary telescope, and they have the pecu-
liarity that their orbits are inclined almost at
right angles to the ecliptic (79°), and their motions
retrograde as compared with the rest of the systems
we have hitherto considered. The distances and
periods of the satellites are :—
d, h. m.
Ariel 124,000 miles Period 2 12 28
Umbriel .. 173,000 69 4 3 27
Titania 285,000 ,, i 8 16 55
Oberon .. 381,000 ,, See eG:
Before the discovery by W. Herschel in 1781 of
the planetary nature of Uranus the planet appears
to have been observed and recorded as a star no
less than nineteen times.
The spectroscope shows the spectrum of Uranus
crossed by six broad bands, one occupying the
position of a hydrogen line, but the rest are not
known.
NEPTUNE.
The story has often been told of the discovery of
Neptune, first on paper in England and France,
and then with the telescope at Berlin. In real
_ size he is believed to have a diameter of 33,011
miles, which means a bulk 72 times that of the
earth, but as his weight, bulk for bulk, is lighter
than any other planet except Saturn, only seven-
teen times the earth’s mass is equal to that of
Neptune. The latest measures of this planet by
Barnard with the 40-inch Yerkes achromatic give
its apparent angular diameter as 2°436''. Neptune
appears asa star of eighth magnitude, and even
with 3:7 inches aperture Webb found it dull and
ill defined. Some of the descriptions given of
its appearance when discovered are certainly
exaggerated, for even with a considerable aperture
there is a want of sharpness about the disc, not to
be wondered at when one considers the small
amount of sunshine that reaches his surface. No
spots have been seen, and the spectroscope shows
a spectrum very like that of Uranus. In 1883
Maxwell Hall in Jamaica believed that he observed
periodical fluctuations of the planet’s brightness,
which might possibly be owing to a rotation on its
axis in less than eight hours. ‘The one satellite
discovered by Lassell with his 2-foot mirror on
October 10th, 1846, rotates, like those of Uranus,
in a retrograde direction. It is about 223,000
miles distant from its primary, has a period of
5d. 21h. 8 m., and shines as a fourteenth magnitude
star. Dawes saw it steadily with his 8-inch Alvan
Clark object-glass, but observation of it is im-
possible with less powerful instruments. Lassell
noted that the satellite was much brighter when
preceding the planet thar when following, making
it very probable that it rotates, like our moon, once
on its axis during one revolution. There is good
reason for believing that Jupiter, Saturn, Uranus,
and Neptune all emit some small amount of light ;
and it may be that in fact they are, in a small mea-
sure, miniature suns in the midst of their satellites.
From the irregularities in Neptune’s movements
the question arises from time to time whether he
is the outermost planet in the solar system as he
travels along his mighty orbit of 8,376,000,000
miles in the long period of nearly 165 years, only
one-third of which has been completed since his
discovery in 1846.
(To be continued.)
|PHOTOGRAPHY
CONDUCTED BY B. FOULKES-WINKS, M.R.P.S.
EXPOSURE TABLE FOR DECEMBER.
The figures in the following table are worked out for plates ot
about 100 Hurter & Driffield. For plates of lower speed numbe1
give more exposure in proportion. Thus platesof 50 H. & D.
would require just double the exposure. In the same way,
plates of a higher speed number will require proportionately
less exposure.
Time, 11 a.m. to 1 p.m.
Between 9 and 11 a.m. and 1 and 3 p.m. double
the required exposure. Between 8 and 9 a.m. and
3 and 4 p.m. multiply by 4.
; 9
| | | |
SUBJECT F.5°6) F.8 | F111) F.16) F.22 PF. 32) F.45 | F. 64
—__—— —— — - — | = |= \
SeaandSky.. | ya5 | go | as | ts | & a ete aul
| | |
Open Landscape ) , | a | si | |
and Shipping | J do | ye | 8 Vee Bolu | Z | :
| |
Landscape, with |
| dark _ fore- | | |
ground, Street + j; s + 4 1 2 4 ||
Scenes, and |
| Groups 50 |
| |
| Portraits in ) : | Re
IsesRicoms een Sica Onn mise | 1 aA ir
| Light Interiors 30 1 2 | 4 8 | 16 | 32 60)
Dark Interiors 2 4 8 (16 | 32 60 120 240
The small figures represent seconds, large figures minutes.
The exposures are calculated for sunshine. If the weather is
cloudy, increase the exposure by half as much again ; if gloomy,
double the exposure.
EXHIBITION OF THE ROYAL PHOTOGRAPHIC
SOCIETY OF GREAT BRITAIN.—In our last issue we
gave a description of the interesting display of
apparatus in the Fountain Court. We now pro-
pose to add a more detailed notice of the Pictorial
Section, and shall also refer to some noteworthy
exhibits in the Technical and Scientific Section.
We may at once state that it is our intention to
treat the whole subject from a purely photographic
point of view. We lay stress on this, as it would
appear to be the sole aim of certain exhibitors to
produce something as totally unlike a photograph
as is possible ; and these people consider this to be
“art.” The result is arrived at by purely mechanical
means, and we are inclined to think often by mere
chance. The most simple method of studying the
pictures is to goround the room with the catalogue,
commencing at No.1. This is quite an ordinary
example of a photograph of woodland scenery
in late autumn, by Harold W. Lane, printed in
platinum ; but the exhibitor has finished the picture
in a prettily-designed mount and frame, which pro-
duces a very pleasing whole. The next picture
that arrested our attention was No. 14, by James B.
Johnson, “Against the Breeze”; a charming ex-
ample, full of life and action. It represents a
216
lady making headway against a strong wind,
and the pose of the head, the hand raised to
secure the hat, with the boa streaming out over
the shoulder, give a sense of reality seldom met
with in a pure photograph. It is difficult to
understand how the judges passed by such a suc-
cessful attempt as this No. 14. James Taylor’s
“ Toilers of the Deep,” No. 26, is another example
of good honest work ; and we are glad to see that
it has been reproduced in the exhibition catalogue.
The charm of the picture lies entirely in the suc-
cessful attempt to portray the work performed by
two fishermen landing their fish. The shine and
reflections in the foreground tell the story of a
dull, wet day, which is in perfect keeping with the
rough but weather-proof clothes of the two men.
John H. Gash has, in No. 27, a very good example
of his careful work, finished in carbon; it is
entitled “Jet Working.” No. 36 is one of those
unpleasing efforts of Pierre Dubreuil, entitled
‘“Curieuse,”’ being an exceedingly muddy, blotchy,
under-exposed plate. No. 89 is another example
of the sacrifice of photography for Art, only the
Art is not apparent. No. 143 is reproduced in the
catalogue, and thus becomes a permanent warning
against plate and paper wasting; the print is
entitled ‘‘ Solitude.” There are, unfortunately, a
good many more photographs more or less after
this style, such, for instance, as Nos. 63, 85, 102,
175, 176, 181, 230, and 234. It is with great plea-
sure we turn back to No. 40, ‘ Burning Ghat,
Benares,” by C. C. Branch; this is indeed a
splendid picture and excellent photography, and
we congratulate Mr. Branch upon the successful
manner in which he has handled the subject.
This gentleman has an equally good photograph in
No. 62, ‘‘ The Maharana’s Elephant.” Both pictures
are printedin carbon. No. 70, ‘A Puritan Maiden,”
by 'T. Fitzgibbon-Forde, is a very pretty bromide
enlargement, but has somewhat of an unfinished
appearance, due to a rather bad lighting on the
face. No. 76 isa lovely picture of autumn wood-
land scenery by Geo. H. Faux. Amongst the best
pictures in the exhibition are the following: No. 92,
“The Hour of Rest,” by T. E. Corney-Wilson ;
No. 108, ‘‘ Landing the Catch,’ by J. Croisdale
Coultas; No. 131, ‘“‘Her First Grief,” and No. 133,
“ Honesty,” both by David Blount; No. 145, “58.
Giorgio Maggiore, Venice,” by John H. Gear,
F.R.P.S.; No. 166, ‘‘ Un Maitre d’Armes,” by Furley
Lewis; No. 188, “A Peaceful Afternoon, Kashmir,”
by G. P. Symes-Scutt; No. 217, ‘‘ When the Leaves
have Fallen,” by W. T. Greatbatch, F.R.P.S. ;
No. 220, ‘‘ Portrait of a Lady,” by W. Crooke;
No. 236, “‘ Ready for Market,” by W. M. Warneuke,
F.R.P.S.; No. 245, ‘“ Toilers,” by Thos. Carter ;
No. 274, “An Old Kitchen,” by Burnard Moore
(medal) ; No. 277, ‘‘ The Spinet,” by W. Gill, F.R.P.S.
(medal); and No. 319, ‘“‘The Bridal Rose,” by
Rudolph Erckemeyer, jun. In the Technical Sec-
tion the medal has been awarded to Douglas Eng-
lish, B.A., for a series of photographs of animals
of the rat tribe in their natural habitat. There are
also some very fine studies of large animals by H.
Nouaille Rudge, No. 517 being particularly good.
CHRISTMAS NUMBERS.—The ‘ Journal of Photo-
graphy” has issued one of the most beautiful of
this year’s Christmas numbers. It is about 11 in.
x82 in. in size, with 42 pages and 32 plates.
There is a supplement of 16 pages, representing
mounts for photographic Christmas cards, Some
of the plates are striking in their artistic beauty.
SCIENCE-GOSSIP.
There are a number of articles on various subjects,
critical and suggestive. The first article discusses
and illustrates the work of three prominent French
photographers; they are MM. Robert Demachy,
C. Puyo, and R. Le Begue. The first is a well-
known manipulator of the gum _ bi-chromatic
process. Three of his pictures are reproduced as
plates. There is also a plate by the second
artist and two by the last-mentioned. The
Christmas number of the “ Photogram” is also to
hand with a frontispiece, representing the choir in
Ely Cathedral, by Dr. John W. Ellis. There are
interesting notes on ‘‘A Seat of Photographic
Learning,” which is in the Technische Hochschule,
Charlottenburg, under the control of Dr. Adolf
Miethe. Mr. Ellis Kelsey hasan article on ‘** Night
Photography at Eastbourne,” with numerous illus-
trations. The children are not forgotten, a pretty
series being entitled ‘“‘ Baby and the Gold-Fly.”
PHOTOGRAPHY FOR BEGINNERS.
BY B. FOULKES-WINKS, M.R.P.S.
(Continued from page 118.)
SECTION II. SHUTTERS.
THE instantaneous shutter on a hand camera’ is
as important as the lens itself, and is worthy of
careful consideration. The question is not of sc
much importance when applied to stand cameras,
although we recommend a shutter to be attached
to every camera for both time and instantaneous
exposures. For ordinary stand cameras we do not
think the photographer can do better than use a
Thornton-Pickard time and instantaneous roller-
blind shutter. This we prefer fitted behind the
lens; but if the user is likely to require very short
exposures, it will be necessary to also fit the camera
with a focal plane shutter. The ordinary roller-
blind shutter will give exposures varying from
ath of a second to 4th, and time exposures. A
shutter giving a greater range of speeds is the
Bausch and Lomb diaphragm shutter, which will
' vive arange from -4-th of a second up to 3 seconds,
g t= 100
and time. This shutter, however, works between
the lenses, and is, therefore, not so convenient
when more than one lens is to be used.
A very simple, and at the same time efficient
shutter, is the old drop-shutter, which is cheap and
also useful for ordinary stand-camera work. There
is another almost forgotten shutter, but for land-
scape work, where high speed is not required, it is
one of the best we have ever met with. This is
known as the window-blind shutter, and is worked
by simply pulling a double-acting roller blind
across the front of the lens. It opens at the
bottom, passes upwards across the lens, and comes
down again, finishing the exposure at the bottom
of the opening in the lens. ‘hus it will be seen
that the exposure is considerably more on the fore-
ground portion of the plate than it is to the sky,
and in all landscape work this will be found a
distinct advantage.
For hand-camera work a shutter must be selected
that will give a good range of speeds, varying,
preferably, from ;4;th of asecond to half a second,
and for time. ‘he shutter should also be what
is known as a self-capping or safety shutter—viz.
one that will not open when the shutter is set. Such
cameras as the ‘‘ Newman and Guardia,” ‘‘Adams,”
“Kodak,” etc., are all fitted with these shutters;
but where there is the option of selection a
SCIENCE-GOSSI/P. vil
Revolutionising Pbhotograpby.
CADETT
SPECTRUM
E-Ea ADEs iseanos
AND
LIGHT FILTERS.
ICKARD
CAMERAS
AND
SHUTTERS
Make Photography a
easure.
66 AMBER’ and ‘‘RUBY ”
Cameras for Hand or Stand.
Price from £2 3s. 6d.
S Time and Instantaneous
= Shutter, from 12s. 6d.
- Standard Pattern,
from 18s. 6d.
IWlustrated
Catalogue.
Write for Booklet ‘‘Orthochromatic Photography”
(simplified), by JAMES CADETT. Gratis. Post Free. Prospectus and
4h Entry Form for
New £105 Prize
he Competition
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SOF SS
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SCIENCE-GOSSIP. 217
shutter should at least answer these two essential
properties ; we therefore propose to give a descrip-
tion of the various types of shutters now before
the public.
THE ROLLER-BLIND SHUTTER is undoubtedly
the most popular ever put on the market, and for
years was made solely by the Thcrnton-Pickard
Manufacturing Company. Now it is made by
many firms in various forms. The principle of
this shutter consists of an opaque blind in the
centre of which is an opening : this opening is made
to pass rapidly across the front or back of the
lens, so exposing the plate. ‘The speed at which
this blind travels varies according to the strength
of the spring roller, which can be regulated to the
required exposure. These rollable blind shutters,
HORNTON-||
Piskarn 4
ROLLER TYPE OF SHUTTER.
as a rule, open every time the shutter is set.
They are, therefore, more suitable for stand
cameras than for hand cameras. For time ex-
posures the blind can be arrested midway and
prolonged exposure given. The Thornton-Pickard
shutter has an indicator fixed to it which indicates
the exposure given. ‘The firm also supply a time-
value, if required. With this addition the shutter
is universal in its use, being capable of giving
short time exposures of 3, 3, $, 1, 2, and 3 seconds.
THE “ DIAPHRAGM” TYPE OF SHUTTER is
generally constructed of metal throughout, and
the exposure is made ‘by the movement of metal
leaves actuated by a spring, the opening and closing
of which exposes the plate. The speed at which
these leaves move is governed by a pneumatic
arrangement. Thus speeds varying from ;3,th to
3 seconds can easily be obtained. These shutters
do not open when setting, and, es a rule, they are
supplied with either finger release or with a pneu-
matic ball attachment. Of this type of shutter
the best known are the ‘“ Bausch and Lomb
Diaphragm” shutter, the ‘“‘ Unicum,” the Goerz
“ Sector,” the ‘ Lopa,’ and the Thornton-Pickard
‘““ New Iris” shutter.
THE “ FOCAL-PLANE” SHUTTER is one that bas
come very much to the fore of late, and seems
likely to stay withus. This is also a blind shutter,
but instead of working on the lens it is placed
immediately in front of the plate. The blind has
a variable slot, which is caused to pass rapidly
across the plate, thus exposing the picture thrown
upon it by the lens. The amount of exposure is
governed by the size of the slot and by the tension
of the spring. These are very high-speed shutters,
the exposures obtained by their use varying from
zonoth of a second to ;4th or jth of a second.
When this shutter is used for hand-camera work
some means must be devised for covering up the
lens whilst setting the shutter, otherwise it will
expose the plate during the setting.
THE FLAP SHUTTER is one that is used almost
exclusively by professional photographers for studio
work, and is best known as the ‘‘Guerry.” The
principle is a simple velvet flap, which opens and
closes by means of a pneumatic ball. When the
ball is pressed the flap is raised, and when the ball
is released the flap falls, thus concluding the
exposure, It-is a most useful shutter where quick
exposures are not required, and is very silent and
effective.
FOREGROUND SHUTTERS.—There\is another class,
known as the “ Foreground” shutters. To these
we have already referred when writing on the
“ Window-blind” and ‘“ Flap” shutters. We have
also had the opportunity of testing one known as
the “Adjustable.” This is a metal shutter in
which the exposing portion is raised in front of
the lens and returns again to complete the expo-
sure, thus giving considerably more exposure to
the foreground than to the sky. The rate of speed
at which the exposing piece travels is governed by
DIAPHRAGM TYPE OF SHUTTER.
means of a pneumatic piston, and the exposure
can be regulated from ;5th to a second, and also
time can be given.
There are many modifications of these different
types of shutters, but they are all more or less
alike, Given the class of work the shutter will be
required to do, there should be no difficulty in
selecting from the foregoing description the most
suitable type for any purpose.
(Lo be continued.)
JAPANESE WALTZING MICE.
readers give any explanation of the remarkable
behaviour of Japanese waltzing mice, which con-
tinually spin round and round for hours together
—Can any of your
in their cage? I should be glad also of any
information as to their natural condition.—W. J.
Pinckney, St. Leonards-on-Sea.
PHOTOGRAPHY v. DRAWING.—At the close of a
lecture before the South London Natural History
Society on November 14th a discussion arose on
the respective merits of photographs and drawings
for the portrayal of natural history objects. The
question is of the greatest importance, and one
whose consideration is worth the attention of all
who may wish to illustrate scientific publications
or lectures. As my efforts have been chiefly
directed toward the elucidation of the structure
and hahits of the Araneidea, I think that I had
better base these remarks upon that order. Fcr
convenience we will consider only the case of
workers possessing equal capabilities both in
photography and drawing. In the first place, for
systematic work intended to facilitate the identifica-
tion and classification of natural objects, accurate
drawings are absolutely necessary.. Photographs,
if not useless, are of little value without diagram-
matic details. In support of this opinion I may
state I have never published a photograph of
scientific details, although such a_ procedure
necessitates far less labour than the preparation of
line drawings. ‘The field naturalist, however, is
constantly bronght face to face with occurrences,
possibly habits inherent to a species, perhaps
merely incidents, which may or may not be
of scientific value. The delineation of such
phenomena would absorb a very considerable,
and indeed almost unjustifiable, amount of the
time at the disposal of the worker desirous of
acquainting himself with the general structure of
the representatives of a natural order. ‘The habits
of many of these creatures, however, are of absorb-
ing interest, and their consideration undoubtedly
tends to detract from the possibilities of a study
drifting into the depths of abysmal obscurity, and
of its devotees becoming mechanical and soulless
slaves to rules and systems. Here photography
comes to the rescue, not only as a recreation, but
as ameans of arousing interest in the minds of
other individuals who might, perhaps, in years to
come, develop those studies which are in their
infancy. Another phase of scientifie photography
which was discussed was the production of photo-
micrographs. Thenecessity of employingartificially
flattened preparations is, 1 agree, a most serious
disadvantage, but even these reprehensible pro-
ductions are not without their uses. In the study
of the tarsal claws of spiders crushed prepara-
tions are of great value, and the relative length of
the joints of the legs may be measured with the
greatest facility from photomicrographs. This
method not only involves a considerable saving of
SCIENCE-GOSSIP.
time, but is an incalculable relief to the eyes of
the busy arachnologist. One further point deserves
a passing notice. The methods most suitable for
lectures may not be thoroughly satisfactory for
deep research. A lecture upon a neglected group,
delivered before an audience of whom perhaps
seventy-five per cent. have already specialised in
other studies, and most of the remaining twenty-
five per cent. will never enter upon any systematic
investigation, should be more or less of a popular
nature. Especially should this be the case if the
lecturer announces his willingness and desire to
help a beginner along the seldom-trodden and
labyrinthine paths of the study to whose interests
his own life-energies are devoted.—Frank P. Smith,
15 Cloudesley Place, Islington, London.
Ice Discs oN LEAVES.—At the beginning of
November there were four days of very thick fog,
with several degrees of frost each night. During
the day a heavy continuous dropping of the con-
densed moisture of the fog was taking place under
trees. The ground was perfectly dry in places
exposed to the sky, but exceedingly wet under the
canopy of foliage. Where trees overhung the roads
the amount of water deposited became so large
that when there was a slight incline it overflowed
the dry, dusty portion as a rivulet until it reached
the ditch. The roads were thus banded with dry
and muddy belts) One afternoon during this time
I observed a curious phenomenon beneath some
hedge-row elms. The road was carpeted with
their fallen golden leaves, about half of the year’s
foliage still clinging to the trees. As lapproached
I saw that there were strewn irregularly here and
there over the surface of the grounda large number
of white objects. ‘They were roundish. ‘and from
14 to 2 inches in diameter. The appearance was
as if a quantity of small white poplar leaves had
been scattered over the surface. My curiosity
was aroused at the sight, and when I came
up to the spot I saw that these remarkable
disc-like objects were in reality lumps of ice.
They were formed of clear transparent ice about
‘one-eighth of an inch thick and were exactly
the size and shape of the elm leaves. The con-
densed fog had accumulated as a layer of water on
some of the leaves on the trees that were in a
suitable position for such an occurrence, and had
frozen on to them during the night. The next day
a slight rise in the temperature must have loosened
the ice discs from the leaf, and they floated un-
broken to the yround, alighting on the strewn leaf-
carpet. The leaves on which they had grown may
have descended at the same time, but the prostrate
discs were dissevered from them, lying quite loosely
on their amber couch. The farmer at whose door
the phenomenon was occurring had also observed
the strange flight, and remarked how ‘the ice be
a-comin’ doon from the trees.” An event such as
this may not be uncommon on the needles of
conifers or other evergreen leaves, though I do not
recollect having heard of it, but I am inclined to
regard it as unusual when taking place on a
deciduous-leafed tree. As a rule the leaves will
have already fallen from such trees before we enter
the climatic conditions which render this feat
possible ; but fogs and frost set in with sudden and
early severity this year. It will be interesting to
hear if notes on ice discs reach you from other
parts of the country, as the fog spread over a large
area.—(Mrs.) I. J. Armitage, Dadnor, Hereford-
shire, November 9th, 1901.
SCIENCE-GOSSTIP. 219
CONDUCTED BY C. AINSWORTH MITCHELL,
B.A.OXON., F.1.C., F.C.S.
SELENIUM 1N BEER.—The element selenium has
recently attracted considerable attention from the
fact of its having been detected by Tunnicliffe and
Rosenheim in a sample of invert sugar, and in two
of the samples of the beer which caused the
epidemic of arsenical poisoning. Selenium, which
is closely allied to sulphur in its physical and
chemical properties, was discovered by Berzelius
in 1817 in a reddish-brown deposit in the leaden
chambers in which sulphuric acid had been manu-
factured. It is a common constituent of certain
varieties of iron pyrites used as the source of oil
of vitriol. Like sulphur, it can exist in several
modifications, and is known as a reddish-orange
deposit, a black vitreous mass, and in the form of
crystals. It burns with a bluish flame, the vapours
of the combustion having a characteristic un-
pleasant odour. It combines with hydrogen to
form a poisonous gas, known as _ seleniuretted
hydrogen, which when passed through a hot narrow
glass tube is decomposed, leaving an orange mirror
of selenium on the cooler portion of the tube. It
combines with metals to form various selenides
which are analogous to the corresponding metallic
sulphides. When heated with sulphuric acid it
dissolves, forming a green solution, from which
the selenium can be separated again on adding a
large amount of water. It is said to produce
peripheral neuritis, resembling that of arsenical
poisoning, though the symptoms are much less
marked. Hence the theory was formed that
selenium played a distinct though subsidiary part
in the recent poisoning epidemic. As, however,
hundreds of other samples of beer have been
examined without its presence having been de-
tected, the conclusions drawn by Messrs. Tunnicliffe
and Rosenheim stand in need of confirmatory
experimental evidence.
ALKALINE WATERS FROM THE CHALK.—It has
frequently been noted that waters from deep wells
in London and other places where the chalk is
covered by a layer of clay differ completely in
character from waters obtained from the un-
covered. chalk. Thus in a water of the former
class there are only traces of calcium carbonate
and magnesium carbonate, but considerable quan-
tities of alkaline salts, and the water is soft and
alkaline. On the other hand, in a typical water
from the uncovered chalk there is a large propor-
tion of calcium and magnesium carbonates which
render the water hard. Various theories, such as
the infiltration of sea water, have been proposed to
account for the occurrence of alkaline salts in the
chalk waters from beneath the clay, but the most
satisfactory explanation is that recently offered by
Mr. W. W. Fisher. He points out that the London
Clay offers an impervious barrier to the passage of
the water, which must therefore have slowly
travelled through the porous chalk from the out-
side area, taking up in its passage the soluble salts
which are still present to a considerable extent in
chalk which has no natural outlet through which
these could have been washed away, as in the case
of the surface chalk. In this underground journey
the proportion of alkaline salts will gradually
increase, and the calcium salts show a continual .
diminution. In support of this theory Mr. Fisher
gives the analysis of a specimen of chalk taken
from a boring 500 feet deep in the Tottenham
Court Road. ‘This chalk was distinctly alkaline,
and contained 0°28 per cent. of sodium sulphate,
0-20 per cent. of sodium chloride, and 0-03 per cent.
of sodium carbonate.
ARTIFICIAL PRODUCTION OF DIAMONDS.—A pro-
cess has just been patented in this country by
A. Ludwig, of Bernburg, in Germany According
to this patent, carbon or graphite is heated by
means of an electric current in an atmosphere of a
gas, preferably hydrogen, which has been pre-
viously compressed to the required extent. The
temperature is raised to the point._at which the
carbon ceases to conduct and is converted into
diamond.
TRON IN. HENS’ EaeGs.--Some interesting experi-
ments have been described by P. Hoffmann in the
“Zeit. Anal. Chem.” It was found that on the
average the yolk of an ege contained twelve milli-
grammes of iron oxide, or that the entire egg
without its shell contained 18 milligramme. At-
tempts were then made to increase this proportion
by feeding the hens on an organic compound of
iron known as ferrohaemol, with the result that
the eges contained a few milligrammes more of
iron, and that there was also an increased quantity
in the livers of the birds. In similar feeding
experiments with organic preparations of copper
no copper passed into the eggs.
SALICYLIC ACID IN STRAWBERRIES.—Salicylic
acid, which is a derivative of phenol or carbolic
acid, was originally prepared from oil of winter-
green (Gaultheria), and from salicin, a compound
extracted from willow- bark, but is now manu-
factured by an artificial synthetical process. Asit
possesses but little taste and has strong antiseptic
properties, it has been extensively used as a preser-
vative in various food-products. As regards its
influence on the human system there are diverse
Opinions, but it is significant that the Paris
Academy of Science forbid even the smallest
addition of salicylates to food, as being liable to
cause injury where any weakness of the kidneys or
digestive organs exists. Hence there have been
many prosecutions of the vendors of foods thus
preserved, and considerable attention has been
given to the best methods of detecting salicylic
acid. A few months ago the Cu-toms authorities
in Brazil condemned several Portuguese wines on
the ground of their containing traces of the acid,
but it was subsequently demonstrated by M. da
Silva that certain Portuguese wines contained
normally a small quantity of a substance which,
like salicylic acid, gave a violet coloration with
iron salts. Still more recently Portes and Des-
mouliéres have extracted a similar substance from
fresh strawberries, and have identified it beyond
doubt as salicylic acid. It was present in the pro-
portion of about one part ina million. As salicylic
acid is frequently adaed to jams as a preservative,
the fact of its being a normal constituent of straw-
berries is of great practical importance.
tata!
SOS
SS
S
SS
4,
4,
VY
a
CONTRIBUTED BY W. H. CADMAN.
UsE OF KITES IN STUDYING THE ATMOSPHERE,
During the last few years kites carrying meteoro-
logical instruments have been employed at
several observatories for exploring the upper
regions of the atmosphere. One great. difficulty,
well known to every kite-flyer, prevented anything
like systematic observations being made. Unless
a sufficiently strong wind was blowing, the kites
carrying the physical instruments could not be
flown. Strange to say, this obstacle is now over-
come by a practical application of that instinctive
action of every child when attempting to fly a kite
in little or no wind. The artificial wind created
by the running child to raise his kite is ob-
tained on a larger scale by means of a rapidly-
moving tug-boat. In this way large kites can be
raised in comparatively calm weather by the motion
of the earth-end of the kite string or wire. Mr. A.
L. Rotch raised his instruments to a height of
2,670 feet, and states that his kites rose easily and
steadily in the artificial wind. His experiments
show conclusively that, with a steamer which can
be manceuvred at will, kites can be flown at sea in
almost all weather conditions. |
zou
Org
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Stand with 1 Eyepiece 60
Ditto, completely fitted with 2 Eye-
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mechanical conveniences and workman-
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&c. The power is the most generally useful one
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A medium-priced Instrument, yielding advantages.
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‘EPAM” MICROSCOPE. A highest class Instrument at a very moderate cost.
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Replete with every modern convenience.
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