204 
A message received at Calcutta on June 19 reports 
that an earthquake has shaken the whole ridge of the 
Himalayas from Simla to Chitral. The shock was not 
very violent, but nothing so extensive has been known 
before. 
We have also to record that a violent earthquake 
occurred at Cassano Al Jonio (Calabria) in the morning 
of June 22, accompanied by subterranean rumblings. 
The population was terrified, but no damage was done. 
THE ROVAL SOCIETY SOIREE. 
A BRILLIANT company of ladies and gentlemen 
was present at the Royal Society conversazione 
last week. Many of the exhibits were the same as on 
the occasion of the previous conversazione on May 14 
(see p. 83), but there were some others in addition, and 
these are briefly mentioned below. 
Dr. Morris W. Travers showed apparatus for liquefying 
hydrogen. Hydrogen, when compressed at the ordinary tem- 
perature and allowed to expand, becomes warmer, while air 
under the same conditions becomes colder; at temperatures 
below -—80° C., hydrogen becomes an imperfect gas, in the 
same sense as air, and undergoes cooling on free expansion 
(Joule-Kelvin effect). The gas, under a pressure of 120-150 
atmospheres, passes through coils in the interior of the apparatus, 
which are cooled in solid carbonic acid and alcohol (—78°*5 C.), 
in liquid air (— 185° C.), and in liquid air boiling under reduced 
pressure (—200° C.). It then enters a regenerator coil, and 
expanding at a valve at the bottom is partially liquefied. 
The liquid collects in a vacuum-vessel at the bottom of the 
apparatus ; the unliquefied gas passes upwards through the 
regenerator coil, cooling the gas it contains, and returns to the 
compressor. 
Apparatus for obtaining serial sections of fossils, and restora- 
tions of fossils in wax built up from serial sections, were shown 
by Prof. Sollas, F.R.S. 
Prof. F. W. Oliver exhibited Stephanospermum and other 
fossil Gymnosperm seeds. All the seeds exhibited were from 
the permo-Carboniferous of Grand’ Croix, near St. Etienne. 
They were preserved in silica, and showed remarkable preserva- 
tion of detail. The majority of the sections were of Stephano- 
spermum akenioides, the seed in which a pollen-chamber was 
first discovered by Brongniart in 1875. 
Photographs of the Rocky Mountains of Canada, and objects 
collected, were shown by Mr. Edward Whymper. 
The Silchester Excavation Fund Committee exhibited a series 
of objects illustrative of recent discoveries on the site of the 
Romano-British city of Silchester, near Reading. 
Examples of telephotography in the Alps and Himalayas were 
exhibited by Prof. E. J. Garwood. 
Dr. F. W. Gamble and Mr. Frederick Keeble had an exhibit 
designed to show the chromatophores and colour-changes of 
Crustacea. 
Mr. W. Gowland showed Japanese pictures of Buddhist 
divinities and saints by old masters. 
Mrs. E. Walter Maunder exhibited drawings from two photo- 
graphs of the corona of 1901, May 18, taken at the Royal 
Alfred Observatory, Mauritius. 
A series of photographs illustrative of old customs still extant 
in Hungerford, Knutsford and Corby was shown by Sir 
J. Benjamin Stone, M.P. 
An attempt to reproduce an Aurora Borealis was shown by 
Prof. W. Ramsay, F.R.S. The spectrum of the Aurora Borealis 
has been shown to contain lines due to the pressure of krypton ; 
the great majority of the lines, if not all, are coincident with 
those of the krypton spark spectrum. An electrode-less discharge 
in air gives a spectrum in which the leading green line of krypton, 
5570°5, is distinctly visible at low pressures. This discharge 
can be deflected by a magnet, sending out streamers in the lines 
of magnetic force. The main phenomena of the Aurora are 
thus reproduced. 
A model of the exploring vessel Dzscovery was shown by the 
Joint Antarctic Committee of the Royal Society and Royal 
Geographical Society. 
NO. 1704, VOL. 66] 
NATURE 
[JUNE 26, 1902 
Prof. H. L. Callendar, F.R.S., had on view (1) simple 
apparatus for determining the mechanical equivalent of heat, and 
(2) vacuum-jacket calorimeters. z 
Mr. Edwin Edser and Mr. Edgar Senior showed an experiment 
illustrating a paradoxical consequence of the wave theory of 
light. Light enters a glass prism, of which the angles are equal 
to 90°, 45° and 45°, by one of the mutually rectangular faces, 
the angle of incidence being equal to zero. It is then reflected 
from the hypotenuse face at an angle of 45°, which exceeds the 
critical angle. A photographic grating (3000 lines to the inch) 
is formed on the hypotenuse face, the rulings being parallel to 
the axis of the prism. The secondary wavelets which, according 
to the wave theory, are formed at the clear spaces, produce 
diffraction spectra, of which the first five or six are visible. If 
the grating were absent, no light could leave the hypotenuse face 
of the prism. Thus, light which cannot penetrate the face 
when the latter is clear is freely transmitted when parts of the 
face are rendered opaque. . 
The ‘‘ Grubb” collimating telescope gun sight was shown by 
Sir Howard Grubb, F.R.S. 
The West Indian Volcanoes Committee of the Royal Society 
exhibited specimens and photographs illustrating the fall of 
volcanic dust at Barbados on May 7 and 8._ The principal con- 
stituents of the dust are magnetite, hypersthene, augite, plagio- 
clase (anorthite-labradorite), small pellets of pumice, and fine 
powder composed of minute mineral»particles and disintegrated 
pumice, On heating the dust to about 1200° C., the pumiceous 
constituent fuses, and the mass on cooling forms a vesicular rock 
allied to hypersthene-andesite, but exceptionally rich in crystals. 
(1) Microscopic slides are shown illustrating the composition of 
the dust :—(q) dust as it fell ; (4) magnetite ; (c) hypersthene and 
augite; (¢) plagioclase; (e) pellets of pumice; (/) thin 
section of partially fused mass. (2) Photographs of vegetation 
covered by volcanic dust, taken at Barbados on May 8, by Mr. 
W. J. Freeman. The specimens were forwarded by Dr. 
Morris, of the Imperial Agricultural Department of the West 
Indies, to Prof. Judd, C.B., F.R.S. The charts were lent by the 
hydrographer of the Admiralty. 
Specimens of volcanic dust from the West Indies were also 
shown by Mr. Henry Crookes. 
Mr. E. J. Bles exhibited living tadpoles of the Cape clawed 
frog, Xenopus /aevis, Daud. The remarkable transparency allows 
the course of the nerves, blood-vessels, muscles, &c., of the head 
to be easily studied in the living animal. A method of feeding, 
not hitherto described in the Amphibia, can be watched. Bred 
from specimens kept in Cambridge for more than five years. 
A series of specimens illustrating the life-history of the 
Trypanosoma Brucit was shown by Mr. H. G. Plimmer. This 
organism is the cause of nagana, or the tsetse-fly disease in 
South Africa. 
Colonel Bruce, F.R.S., and Mr. H. G. Plimmer, exhibited 
Apiosoma bigeminum, the parasite found in the blood of Texas 
fever of cattle. 
New species of fairy flies(Mymaridze) were shown by Mr. F. 
Enock. The species are all ovivorous, some laying their eggs 
in those of the water demons (Dytiscus) ; as many as seventy-two 
larvee of one species have been found in ome egg of D. mar- 
ginalis, Living specimens, 27 sz¢z, and possibly some emerging. 
The Royal Society exhibited a bronze example of the newly 
founded David Edward Hughes medal, and a medallion of the 
reverse. 
Dr. A. Dendy had on view specimens, sketches and photo- 
graphs of Moriori workmanship from the Chatham Islands. 
A series of otoliths, chiefly of living British fishes, both marine 
and freshwater, showing the various forms assumed in the 
different genera, was shown by Mr. E. T. Newton, F.R.S. 
Prof. W. M. Flinders Petrie, F.R.S., exhibited a series of 
worked flints from Egypt. 
Experiments exhibiting interference between portions of light 
from independent sources were shown by Dr. G. Johnstone 
Stoney, F.R.S. 
During the evening, demonstrations, with the help of the 
electric lantern, were given by Prof. W. M. Flinders Petrie, 
F.R.S., on early civilisation in Egypt; Mr. J. Y. Buchanan, 
F.R.S., a series of lantern slides illustrating the performance of 
M. Santos Dumont’s steerable balloon and the accident to it on 
February 14; and Prof. E. B. Poulton, F.R.S., on recent 
work upon protective resemblance and mimicry in insects, illus- 
trated by three-colour slides. 
