104 
NATURE 
[Marcu 28, 1912 
galvanometer in the thermopile circuit will be zero. 
A long series of experiments showed that the light 
could be kept constant within +0-5 per cent. when a 
constant temperature was maintained by the above 
criterion.—J. A. Crowther: The distribution of the 
scattered Rontgen radiation. Experiments have been 
made to determine accurately the distribution of the 
scattered R6ntgen radiation round a radiator. It has 
been found that the radiation can be divided into two 
parts : a true scattered radiation, distributed in accord- 
ance with the usually accepted theory of the scatter- 
ing, and an additional or excess radiation. The 
curves representing the distribution of the latter have 
been found to resemble those previously obtained for 
a parallel pencil of 8 rays after passing through thin 
sheets of matter.—E. A. Owen: The passage of homo- 
geneous Rontgen rays through gases. (1) The 
absorption coefficient of the different homogeneous 
radiation in a light gas such as CO, or SO, is pro- 
portional to the absorption of radiations in air. 
(2) The absorption of homogeneous radiation in a 
gas is proportional to the pressure of that gas. (3) For 
the homogeneous rays emitted by metals of atomic 
weight ranging from that of iron to that of molyb- 
denum, the coefficient of absorption in the gases in- 
vestigated is approximately inversely proportional to 
the fifth power of the atomic weight of the radiator 
which emits that characteristic radiation, i.e. Aew-5, 
(4) The amount of ionisation produced in a thin layer 
of a gas is directly proportional to the pressure of the 
gas. (5) The ionisation relative to air is approxi- 
mately constant in the same gas for the different 
homogeneous rays. (6) The total number of ions 
produced by homogeneous beams of equal intensity is 
approximately the same in each gas for any particular 
type of rays.—J. C. Chapman: Fluorescent Réntgen 
radiation from elements of high atomic weight.—J. A. 
Gray: The nature of y+ rays excited by B rays. A 
determination has been made of the relative amount 
of emergent and incident y radiation excited in 
“radiators” of different thicknesses and different 
materials. Results of the experiments are :—(1) The 
emergent y radiation is generally greater in amount 
than the incident radiation, and is more penetrating. 
(2) The ratio of emergent to incident y radiation is 
greater, for radiators of the same material, the 
thinner the radiator; for radiators of different 
materials thick enough to stop the 6 rays, the lower 
the atomic weight of the radiator. (3) The results 
obtained point to the conclusion that the excited y ray 
is an entity, the direction of which is nearly that of 
the 6 ray exciting it. (4) The chance of a B ray 
making a y ray is roughly proportional to the atomic 
weight of the radiator, provided the 8 ray spends its 
range in the radiator. 
Geological Society, \Warch 13.—Dr. Aubrey Strahan, 
F.R.S., president, in the chair.—Dr. R. L. Sherlock 
and A. H. Noble: The glacial origin of the Clay- 
with-Flints of Buckinghamshire, and on a former 
course of the Thames. The superficial deposits are 
divided into Clay-with-Flints with the associated 
Gravelly Drift, and the Fluvioglacial Gravels. 
Certain high-level gravels, older than any of these, 
and also the river-gravels and alluvium of the present 
streams, are not dealt with in the paper. The 
evidence shows that the Clay-with-Flints and Gravelly 
Drift were formed by an ice-sheet which came from 
the north or north-west over the Chiltern Hills. Only 
the clean upper layers of ice surmounted the escarp- 
ment, and this produced the Clay-with-Flints and 
Gravelly Drift. At that time the Thames flowed 
from Bourne End through Beaconsfield and Rick- 
mansworth to Watford. The ice-sheet blocked the 
river-channel between Bourne End and_ Riclkmans- 
NO. 2213, VOL. 89] 
worth, and diverted the Thames southwards at 
Bourne End. The river beyond Watford was further 
blocked by the Eastern Drift. On the melting of the 
ice, Fluvioglacial Gravels were left over a great area. 
These gravels are composed chiefly of Eocene and 
Cretaceous materials derived from the Gravelly Drift. 
The floods from the melting ice, added to the waters 
of the Thames and Colne, produced the great flat 
through which the Thames now flows. After the re- 
treat of the ice, the Wye and Misbourne extended 
their channels over the Fluvioglacial Gravel flat, and 
some other small streams were formed.—Jane 
Longstaii: Some new Lower Carboniferous gastero- 
poda. Eight species of gasteropoda are described, 
six being regarded as belonging to five new genera 
or subgenera, the others representing Pithodea, De 
Koninck, which has not previously been recorded 
from the British or Irish Carboniferous Limestone. 
Linnean Society, March 21.—Dr. D. H. Scott, 
F.R.S., president, in the chair.—Dr. I. Bolivar and 
C, Ferriére: Orthoptera-Phasmidze of the Seychelles. 
—J. A. Liddell: Nitocrameira bdellurae, a new genus 
of parasitic Canthocamptidae.—W. West and Prof. 
G. S$. West: The periodicity of the phytoplankton of 
some British lakes. 
Paris. 
Academy of Sciences, March 11.—M. Lippmann in 
the chair.—C, Guichard: Osculating circles and oscu- 
lating spheres to the lines of curvature of a surface. 
—M. Lucas-Championniére was elected a member of 
the section of medicine and surgery in the place of 
the late O. M. Lannelongue-—MM. Fayet and 
Schaumasse: The elliptical character of the Schau- 
masse comet (1911h).—E. Vessiot: Permutable func- 
tions and continuous groups of linear functional 
transformations.—V. Jamet: Certain complexes of 
lines.—Rodolphe Soreau: Generalisation of Massau’s 
construction and abacus for solving equations of 
the form 27+ + 72°89 + #28 + ¢ =o—MM. Papin and 
Rouilly: The gyropter. Two diagrams completing 
the note published on March 4.—Samuel Lifchitz : 
The displacement of the particles in the Brownian 
movement. The explosive shock of the spark as the 
cause of the phenomenon.—Ch. Féry: A new thermo- 
electric combustion calorimeter. A calorimetric 
bomb is fixed by two dises of constantan in an external 
metallic envelope, the latter and the constantan discs 
forming a thermocouple.. The rise of temperature 
observed, which is high owing to the absence of 
water, is read directly on a _ millivoltmeter.—Jean 
Escard: Some practical arrangements for the deter- 
mination of the densities of solid bodies of small 
volume. <A description of a volumometer modified to 
measure accurately the density of solids having 
volumes from 1 c.c. to 3 ¢.c.—P. Th. Muller and E. 
Carriére : The refraction and dispersion of the mercury 
nitrates.—J. Meunier: Some mechanical phenomena 
of gaseous combustion. The spiral flame.—H. 
Baubigny : Researches on the formation of dithionic 
acid in the reaction between alkaline sulphites and 
copper salts.—V. Hasenfratz: Apoharmine-carboxylic 
acid, apoharmine, and some derivatives of this base. 
—Marcel Sommelet: y-Ethoxyacetoacetic ester. This 
ester is obtained by the interaction of ethoxyacetic 
acid, bromacetic acid, and zinc—Mme. Ramart-Lucas : 
The action of phenylmagnesium bromide upon pina- 
coline and on methylpinacoline.—H. Pariselle: Study 
of the unsaturated alcohol 
CH,=CH—CH,—CH(OH).—CH,. 
This alcohol was prepared by the interaction of ally! 
bromide, acetaldehyde, and magnesium. Its proper- 
ties are described, and also those of its acetate and 
chloride.—Marcel Guerbet: The action of caustic 
= 
