DECEMBER 17, 1896] 
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Harry Johnston, K.C.B. The present collection contained | 
examples of fourteen species, of which five were now described 
as new to science. —A second communication from Mr, Boulenger 
contained remarks on the lizards of the genus Zvemzas. section 
Boulengeria,—Mr. R. Lydekker, F.R.S., gave an account of an 
apparently new deer from North China, living in the menagerie 
of the Duke of Bedford, at Woburn Abbey, to which he pro- 
posed to assign the name Cervus bedfordianus.—The Secre- 
tary read a communication from Mr. A. J. North, of the 
Australian Museum, Sydney, containing an account of a cuckoo 
in the Ellice Islands (2udynamys ‘aztensis), which appears to 
lay its eggs in the nest of a tern (Azzozs stodzdus).—The Rev. T. 
R. R. Stebbing communicated a paper by Dr. H J. Hansen, 
of the Copenhagen Museum, on the development and the 
species of the Crustaceans of the genus Sergesées. 
Entomological Society, December 2.—Dr. Sharp, F.R.S., 
Vice-President, in the chair.—Dr. Sharp exhibited the series 
of Longicorn Coleoptera of the genus Plagithmysus from 
the Hawaiian Islands, of which a preliminary account had 
recently been given by him elsewhere. He said that these 
examples were the result of Mr. Perkins’ work for the Sandwich 
Islands Committee, and afforded a fair sample of his success 
in the other orders, which would be found to have completely 
revolutionised our knowledge of ‘the entomological fauna of 
these islands. He stated that Mr. Meyrick had recently 
informed him that the Geometride would be increased from 
six species to forty-four, and that the genus Plagithmysus 
showed an almost equal increase ; and that the working out 
of the specimens was very difficult, owing to the variability 
of the species and to their being closely allied.—Mr. Malcolm 
Burr exhibited a specimen of a cockroach, Pycnoselus zndicus, 
Fabr., taken in a house at Bognor, Sussex. He said this 
was the first record of the occurrence of the species in 
England. According to De Saussure, it was distributed 
throughout India, Ceylon, Mexico, and the United States.— 
Mr. P. Crowley exhibited a remarkable variety of Adraxas 
grossulartata taken in a garden at Croydon last summer.— 
Mr. Tutt exhibited some Micro-Lepidoptera from the Dauphiné 
Alps. Several specimens of Psecadia pusiedia, Rom:, showing 
considerable difference in the width of the black zigzag band 
crossing the centre of the forewisgs longitudinally. The 
species was taken at La Grave, in a gully at the back of the 
village. A large number of specimens were secured, chiefly 
resting on the trunks and branches of two or three ash and 
willow trees growing on the bank at the side of the gully. 
A few specimens, however, were obtained drying their wings 
on the grass on the bank, but Mr. Tutt stated that he failed 
to find pupa-cases. Mr. Tutt also exhibited specimens of a 
“‘plume” which had been named Lesoptdlus (Aluctta) scaro- 
dactyla. He also exhibited specimens, from Le Lautaret, of 
Gelechia spuriella, Sophronia semizcostella, Pleurota pyropella, 
Bcophora stipella, and Butalis fallacella. The latter were 
chiefly interesting from the fact that they were taken at an 
elevation of about 8000 feet.—Lord Walsingham, F.R S., 
read a paper entitled, ‘‘ Western Equatorial African Micro- 
Lepidoptera.” A discussion ensued, in which Dr. Sharp, 
Herr Jacoby, and others, took part. 
CAMBRIDGE. 
Philosophical Society, November 9.—Mr. F. Darwin, 
President, in the chair.—‘*‘On the Nature of the Réntgen 
Rays,” by Prof. Sir G. G. Stokes. In this communication the 
author explained the views he had been led to entertain as to 
the nature of the Rontgen rays, and to a certain extent the 
considerations which had led him to those conclusions. As 
Ro6ntgen himself pointed out, the X-rays have their origin in 
the portion of the wall of the Crookes’ tube on which the so- 
called kathodiec rays fall, and it is natural that notions as to the 
nature of the X-rays should be intimately bound up with those 
entertained as to the nature of the kathodic rays. Two different 
views have been adopted on this question. Several eminent 
German physicists hold that the kathodic rays are essentially a 
process going on in the ether, the nature of which nobody has 
been able to explain; and that if any propulsion of molecules 
from the kathode accompanies them, it is merely a secondary 
phenomenon The other view is that the kathodic rays are not 
proper rays at all, but that they are essentially streams of 
molecules. The author expressed the fullest conviction that 
the kathodic rays are no mere process going on in the ether, 
but that the propulsion of molecules is of the very essence 
NO. £416, VOL. 55] 
of the phenomenon; only it is to be remembered that 
the molecules are not to be thought of as acting merely 
dynamically, by virtue of their mass and velocity ; they are 
carriers of electricity ; and it would seem to be mainly to this 
circumstance that some at least of their effects are due. He 
indicated what he believed to be the true answers to the objec- 
tions of those who regard the kathodic rays as processes in the 
ether; and adopting the theory that they are streams of 
molecules explained how, in his opinion, this theory, taken in 
connection with the more salient features of the X-rays to which 
the kathodic rays give birth, leads us to a theory of the nature 
of the X-rays. Everything points to the X-rays as being, like 
rays of light, some process going on in the ether, and sufficient 
indications of their polarisation appear to have been obtained 
(at least when those indications are taken along with the 
undoubted polarisation of the Becquerel rays with which they 
have so many properties in common) to refer the Rontgen as 
well as the Becquerel rays to a disturbance transverse to the 
direction of propagation. The absence of refraction, which is 
so remarkable a feature of the X-rays, suggests that their 
progress through ponderable matter takes place by vibrations in 
the ether existing in the interstices between the ponderable 
molecules ; a view which, if correct, leads incidentally toa some- 
what novel view as to the mechanism of the refraction of light. 
The absence, or almost complete absence, of diffraction and 
interference of the X-rays leads to one of two alternatives— 
either that they are of excessively short wave-length, or. that 
they are non-periodic or only very slightly periodic, the X-light 
being on the latter supposition regarded as a-vast succession of 
independent pulses analogous to the *‘ hedge-fire”’ of a regiment 
of soldiers. According to the author's view, each electrically 
charged molecule on arrival at the target gives rise to an 
independent pulse, and the vastness of the number of pulses 
depends on the vastness of the number of molecules in even a 
minute portion of ponderable matter.—‘‘On the Contact 
Relations of certain Systems of Circles and Conics,”” by Mr. W. 
McF. Orr.—‘‘ On certain cases of discharge in vacun, and on the 
zigzag path of Lightning,” by Mr. J. Monckman. 
PaRIs. 
Academy of Sciences, December 7.—M. A. Cornu in 
the chair.—Pleurisy in man studied by means of the Rontgen 
rays, by M. Ch Bouchard. The existence of pleurisy in the 
human subject is very clearly indicated by the Rontgen ray 
shadows, but the method offers no advantages over the ordinary 
clinical diagnosis. —On the composition of the gases which are 
evolved from the mineral waters of Bagnoles de Orne, by 
MM. Ch. Bouchard and Desgrez. The gas contained traces of 
helium, 4°5 per cent of argon, 5°0 per cent. of carbon 
dioxide, the remaining 90°5 per cent. being nitrogen.— 
The theory of the confluence of the lymphatics and the 
morphology of the lymphatic system of the frog, by M. L. 
Ranviér.—On the quaternary elephants of Algeria, by 
M. A. Pomel. In the two quaternary geological horizons 
six species of elephant have been found, the distinguish- 
ing characteristics of which are described.—The quaternary 
rhinoceri of Algeria, by M. A. Pomel.—Observations on the 
total solar eclipse of August 9, 1896, made in Japan by M. H. 
Deslandres.—Optical analysis of urine, and the exact estimation 
of proteids, glucosides, and saccharoid non-fermentable 
materials, by M. Fr. Landolph.—Germination of the spores of the 
truffle, by M. A. G, Grimblot.—Modification of a fundamental 
principle relating to imaginary quantities, by M. L. Mirinny.— 
An air compressor with two cylinders, by M. J. Niffre.—Com- 
parison of the observations of Vesta with the tables, by M. 
Leveau.—On a class of paraboloids, by M. A. Mannheim.—On 
the problem of Dirichlet and the fundamental harmonic functions 
attached to a closed surface, by M. Le Roy.—On the equations 
representable by three linear systems of points, by M. Maurice 
d’Ocagne.—The construction of standard plates for the optical 
measurement of small air thicknesses, by MM. A. Perot and 
Ch. Fabry.—On the property of discharging electrified con- 
ductors communicated ,to gases by the X-rays by flames and by 
electric sparks, by M. Emile Villari. A reply to the claim for 
priority in this subject by M. E. Branly.—On lithium nitride, 
by M. Guntz. It is practically impossible to prepare lithium 
nitride in a pure state, as it exerts a solvent acfion upon every 
substance used as a containing vessel.—On the heat of forma- 
tion of selenic acid and some selenates, by M. René Metzner. 
Measurements are given for the heat of neutralisation of seleni 
