NovEMBER 12, 1896] 
NARORE 
47 
peratures inside vacuum tubes, by Rk. W. Wood. These are 
measured by a platinum spiral acting as a bolometer. At an 
internal pressure of 0°3 mm, the rise of temperature ranged 
from 13° to 25°7° C. as the current varied from o*0015 to 
070036 amperes. At greater pressures the variation for the 
same current was higher. The author measured the tempera- 
tures of the bright and dark spaces by mounting the spiral on a 
glass arm penetrating into a Torricellian vacuum, and passing 
down through the mercury and up through the tank. This arm 
could be shifted up and down without interfering with the 
vacuum. In every case, the bright spaces were a few degrees 
hotter than the dark ones.—Electrostatic deflection of kathode 
rays, by G. Jaumann. When a quiet line of light is produced 
in a vacuum tube by a feeble current, it may be temporarily 
deflected by moving a rubbed glass or ebonite rod in its neigh- 
bourhood. The author used an influence machine driven by an 
electric motor as a generator, and immersed a pear-shaped tube 
in oil, with the anode outside in the liquid, and not fused into 
the glass. A spot anda ring are produced opposite the kathode, 
and the former is deflected as described. As soonas the motion 
of the electrified body ceases, the spot returns to its first posi- 
tion, after a few oscillations. This phenonemonis quite distinct 
from the permanent deflection produced by neighbouring con- 
ductors. —A simple method of separating alternating discharges 
in vacuum tubes, by R. Hildebrand. Describes various arrange- 
ments of tinfoil and other conductors producing permanent 
deflection and curvature of kathode rays, such as are usually 
produced by magnets. Also confirms Jaumann’s observations 
of temporary deflections by electrified rods, but uses an induction 
coil as a source.—The foundations of electrodynamics, by E. 
Wiechert. Introduces the conception of a rotor as representing 
the magnetic displacement instead of a vector, and proves its 
utility in explaining Rontgen and aberration phenomena.— 
Some properties of Rontgen rays, by A. Winkelmann and R. 
Straubel. Attempts to discover refraction by prisms of iron, 
copper, zinc, silver, lead, and platinum failed. The re‘ractive 
index of iron for X-rays does not differ more than 0°00005 from 
unity, and is smaller, if anything. Exposures for shadowgraphs 
may be considerably lessened by placing the sensitive plate face 
downwards upon a plate of fluorspar.—Wave-length of Rontgen 
rays, by L. Fomm. A diffraction experiment gave 0000014 mm. 
as the upper limit of the wave-length. This is about fifteen 
times smaller than the smallest ultra-violet wave-lengths hitherto 
measured. 
SOCIETIES AND ACADEMIES. 
LONDON. 
Entomological Society, October 21.—Prof. Raphael 
Meldola, F.R.S., President, in the chair.—Mr. J. J. Walker 
exhibited a specimen of Emus hirtus, L., taken at Gore 
Court Park, Sittingbourne, Kent, on May 30 last.—Mr. W. B. 
Spence sent, from Florence, for exhibition, some specimens of a 
cricket, Gry//us campestvis, in small wire cages, which he stated 
were, in accordance with an ancient custom, sold by the Italians 
on Ascension-day.—Mr. I. Enock exhibited a specimen of the 
curious aquatic Hymenopteron Prestwechia aguatica, 9, which 
Sir John Lubbock, F.R.S., first captured in 1862, but which 
had not been recorded since that date until its. rediscovery in 
May 1896. Mr. Enock said that the male had remained un- 
known until June last, when he captured several swimming 
about ina pond at Epping. The male was micropterous, and, 
like the female, used its legs for propelling itself through the 
water.—Mr. Tutt exhibited a beautiful aberration of Zephrosia 
bistortata (crepuscularia), in which the ochreous ground-colour 
was much intensified, and the transverse shade between the 
median and subterminal line was developed into a brown band ; 
the transverse basal, median and subterminal lines on the fore- 
wings, and the median and subterminal lines on the hind-wings, 
being particularly strongly marked in dark brown. Mr. Tutt 
also exhibited the cocoons, pupal-skin and aberrations of the 
imago of Zygena exulans. The cocoons were spun upon one 
another, five in a cluster, and Mr. Tutt stated that the species 
was exceedingly abundant in the pupal and imaginal stages 
during the first week of August on the mountain slopes above 
Le Lautaret, in the Dauphiné Alps, at from 7000 to go00 feet 
elevation. The pupa-skin was very similar to those of other 
Zygenids. The imagines exhibited were all aberrations.—Dr. 
Sharp, F.R.S., exhibited a caterpillar which had received the 
NO. I41I, VOL. 55] 
eggs of a parasite on the anterior part of the body, the abdomen, 
nevertheless, went on to the pupal metamorphosis, while the 
head and thorax remained attached to itin the caterpillar stage. 
He also called attention to some peculiarities in the pupa of 
Plusia moneta ; in this species the pigmentation varies greatly in 
extent, and is sometimes entirely absent —Mr. Blandford called 
attention to the recent discoveries relating to the Tsetse fly, made 
by Surgeon-Major Bruce in Zululand, which proved that this 
insect affected animals by injecting them with a_ parasitic 
Protozoon. The parasite was communicated from wild animals 
to domestic animals, and was more widely distributed than was 
generally believed ; it, or a closely allied form, having been found 
in India and England in sewer rats. He said that Surgeon- 
Major Bruce had proved that the Tsetse fly was pupiparous, which 
was of importance as affecting the classification of the Diptera. 
Dr. Sharp said that in his opinion the Tsetse fly would cease to 
be troublesome with the advance of civilisation.—Mr. C. G. 
Barrett exhibited the pupa-skin, cocoon and eggs of Hesperia 
comma, L., found on chalk hills near Reading. He also 
exhibited and remarked on a series of both forms of Zephrosia 
crepuscularia and 7. bzundiularza, showing an unbroken line of 
variation from brown to white and also to grey and black. In 
addition, he showed several second brood specimens of both 
forms obtained in the past summer by Mrs. Bazzett, of Reading. 
—Mr. Tutt read a paper entitled ‘‘On the specific identity of 
Canonympha tphis and C. satyrion,” and exhibited a long series 
of specimens.—The Rey. T. A. Marshall communicated a paper 
entitled ‘* A Monograph of British Braconidze. Part vii.”—Mr. 
T. D. A. Cockerell communicated a paper entitled ‘“‘ New 
Hymenoptera from the Mesilla Valley, New Mexico.”—Mr. E. 
Meyrick contributed a paper entitled ‘‘On Lepidoptera from 
the Malay Archipelago.”—Dr. Sharp read a paper by Mr. G. 
D. Haviland and himself entitled ‘‘ Termites in Captivity in 
England.’ 
Royal Microscopical Society, October 21.—Dr. R. G. 
Hebb, Vice-President, in the chair.—The diploma and medal 
awarded to the Society for photomicrographs exhibited at the 
Columbian Exhibition, Chicago, was laid on the table.—Lieut. - 
Colonel Siddons exhibited and described a new portable dissecting 
stand, and also a lens-carrier for use as a dissecting microscope. 
—Mr. C. Beck made a communication on the new screw-tools 
for objectives. —Prof. F. J. Bell reported that the microscopes 
of historical interest belonging to the Society had been exhibited 
at a conyersazione of the Pathological Society, and were now on 
view.—Mr. J. Butterworth read a paper on a photomicro- 
graphic camera designed chiefly to facilitate the study of opaque 
objects, illustrating his remarks by a series of lantern slides 
shown on the screen.—Mr. T. Comber read a paper on the 
occurrence of endocysts in the genus Zha/asséostra.—Mr. G. 
Murray detailed some observations made in connection with 
this subject.—Mr. F. Chapman gave a réseé of the ninth 
part of his memoir ‘On the Foraminifera of the Gault of 
Folkestone.”-—Mr. E. M. Nelson read a paper on a method of 
measuring the apertures of objectives. 
MANCHESTER. 
Literary and Philosophical Society, October 20.—Mr. 
Charles Bailey, Vice-President, in the chair.—Mr. A. Griffiths 
read a paper on concurrent observations of viscosity and electric 
conductivity of a salt solution containing gelatine, which was 
allowed to set slowly at a constant temperature. He finds that 
the resistance does not appreciably alter even when the viscosity 
becomes very great. Mr. Griffiths subsequently communicated 
a note on the resistance of a conducting jelly, containing iron 
filings, in the magnetic field. He finds that a resistance so 
constituted becomes less by 25 per cent. ina field of 2000C.G.S. 
units. 
PaRIs. 
Academy of Sciences, November 2.—M. A. Cornu in the 
chair.—On the disaggregation of comets, by M. O. Callandreau. 
The disaggregation of a comet swarm is found to depend on its 
density and on the nature of its path, being more marked in an 
elongated orbit.—The gyroscopic horizon of Admiral Fleuriais, 
by M. E. Guyou. A description of the adaptation of the gyro- 
scope by the late Admiral Fleuriais for giving the vertical plane 
at sea. It possesses considerable practical advantages over the 
pendulum, and is particularly serviceable in places where the 
horizon is hidden by haze or fog, but where the sun can be seen. 
The rotation of the earth is clearly indicated by this instrument, 
anda small correction has to be made on this account.—New 
