Marcu 18, 1807] 
NATURE 
479 
of Scandinavian origin. The author discussed the mode of 
transport to their present position, and favoured the agency of 
floating ice. —Coal : a new explanation of its formation ; or the 
phenomena of a new fossil plant considered with reference to 
the origin, composition, and formation of coal-beds, by W. S. 
Gresley. The author argued that the brilliant black laminze in 
coal and similar materials to those that form these laminze, 
which are found in earthy coals, shales, and clays, point to the 
former existence of an aquatic plant, having the general shape 
of the modern Platycerium adcicorne, which grow iz situ. He 
believed that much coal was formed by this aquatic ‘‘coal- 
plant,’ which grew amongst the mechanical sediments and the 
débris of the terrestrial vegetation that accumulated on the floors 
of sheets of water. 
Zoological Society, March 2.—Dr. W. T. Blanford, 
F.R.S., in the chair.—The Secretary exhibited two specimens 
of a new viper, recently discovered by Captain A. H. McMahon 
during the recent survey of the Indo-Persian frontier, and named 
Existicophis macmahoni (gen. et sp. nov.) by Dr. Alcock. 
This snake had been met with only in the sandy portions of the 
desert between Mushki and Persia, where it was almost impos- 
sible to detect its presence, owing to its habit of lying buried in 
the sand with only its head visible-—Mr. Gambier Bolton gave 
an account (illustrated by photographs shown by the oxy- 
hydrogen light) of a recent visit that he had made to the Bird 
Islands in Saldanha Bay, South Africa. The photographs illus- 
trated the life of the black-footed penguin (Sphevzscus demersus) 
on these islands, showing these birds in groups, nest-building, 
sitting on their eggs, and moulting. Mr. Bolton also gave an 
account of the guano- and egg-industry carried on by the Cape 
Government in the Bird Islands and other adjacent islands. — 
Mr. W. B. Tegetmeier exhibited and made remarks upon a 
specimen of a starling (Stars vulgaris) with enormously 
elongated mandibles. —Mr. H, M. Wallis read a paper entitled 
“The Growth of Hair upon the Human Ear, and its testimony 
to the Shape, Size, and Position of the Ancestral Organ.” 
Entomological Society, March 3.—Mr. R. Trimen, 
F.R.S., President, in the chair,—Mr. George W. Bird, Mr. 
Alfred H. Martineau, Mr. Hubert C. Phillips, Mr. William A. 
Vice, and Mr. Colbran:J. Wainwright were elected Fellows of 
the Society. —Mr. Champion exhibited, on behalf of Messrs. 
Godman and Salvin, a portion of the Elateridz, and the 
Cebrionide and Rhipidoceridze recently worked out by him in 
the ‘* Biologia Centrali-Americana.”” The Elateridze included 
531, the Cebrionidee 29, and the Rhipidoceridz 14 species, a 
large proportion of which were described as new. He called 
attention to the excessive rarity of the males in the Elaterid 
genera Chalcolepidius and Semzotus (the contrary being the case 
in the genus Scaplolenus of the Cebrionidz, and also in many 
Elateride). One species, Merzsthus scobinula, Cand., was 
common to Central America and China.—Mr. Jacoby showed a 
Halticid beetle, taken in Mashonaland by Mr. G. A. K. 
Marshall, and remarkable for a prolongation of the hind tibia 
beyond the tarsal articulation into a very long serrated process. 
—Mr. Elwes showed a series of Papilionidee of the A/achaon 
group, from North America, including P. machaon and P. 
oregonia from British Columbia, P. érucez, P. bazrdiz, and 
P; solicaon from Glenwood Springs, Colorado, and the latter 
species from British Columbia. He stated that there was a 
tolerably complete gradation from P. ovegonzéa (= machaoie) 
through P. drucet to P. zolicaon, that none of the characters 
which had been relied on for separation were of real value, and 
that the structure’ of the genitalia afforded no assistance.—Mr. 
O. H. Latter read a paper on ‘‘ The prothoracie gland of 
Dicranura viniula, and other notes,” in continuation of. his 
previous communications on the subject. A fresh use of the 
formic acid secreted by the larva was described ; it was em- 
ployed to alter the silk secreted in spinning the cocoon, in order 
to convert it into the well-known horny mass. If the acid was 
prevented from acting, as by supplying the larvae with bits of 
blotting-paper soaked in an alkali to be utilised in making the 
cocoon, the silk thus protected from the action of the acid re- 
tained its usual fibrous structure.—Sir George Hampson com- 
municated a paper on ‘‘ The Classification of two subfamilies of 
Moths of the Family Pyralide—the Aydrocampine and 
Scopariane.” 
CAMBRIDGE. 
Philosophical Society, February 22.—Mr. F. Darwin, 
President, in the chair.—On the diffraction pattern near the 
focus of a telescope, by Mr. R. H. D. Mayall. 
NO. 1429, VOL. 55] 
The diffrac. 
tion pattern dealt with in this paper is supposed to be 
formed by the light from a star, upon a screen placed near the 
focus of a telescope. Series have been given by Lommel for 
the calculation of the intensity of illumination at any point of 
the pattern, but these become useless when the screen is more 
than a millimetre distant from the focus of a telescope of 
ordinary aperture. The series may, however, be transformed 
into a shape from which approximate values of the intensity may 
be found. This is shown in the present paper. It appears 
from the results that the pattern consists of a bright and com- 
paratively broad ring surrounding a series of fainter and 
narrower rings, these latter fading away rapidly into a uniformly 
illuminated space. Further inwards towards the centre the 
uniform illumination disappears and another series of rings is 
formed.—On the marks made by stars on photographic plates 
exposed near the focus of a telescope, by Mr. H. F. Newall. 
In this paper an account is given of some of the appearances 
presented by photographs of star images taken near the focus of 
a telescope, with special reference to the concentration of light 
near the boundaries of the images when the aperture of the 
telescope is partly obstructed. The observations recorded are 
in the main supplementary to those which were published in 
the Monthly Notices of the Royal Astronomical Society in 1894 
and suggested the theoretical investigation undertaken by Mr. 
Mayall.—Theorems on the contacts of spheres, by Mr. W. 
McF. Orr.—Change of the independent variable in a differential 
coefficient, by Mr. E. G. Gallop.—On a method of Lie for 
solving partial differential equations, by Dr. A. C. Dixon. 
PARIS. 
Academy of Sciences, March 8.—M. A. Chatin in the chair. 
—Kesearches on the earths contained in the monazite sands, by 
MM. Schutzenberger and Boudouard.—The sulphate of cerium 
obtained from monazite sand gave numbers on analysis indicating 
an atomic weight sensibly higher than the cerium sulphate 
obtained from cerite. It was found possible to break up the 
former into three fractions, one not precipitated from solution 
by cupric oxide, with an atomic weight of 138, another precipi- 
tated from the solution of its sulphate by both cupric oxide and 
by sodium sulphate (atomic weight about 148), and the third 
precipitated by cupric oxide, but not by sodium sulphate (atomic 
weight about 157).—On the apparatus employed to collect 
samples of air at a great height, in the ascent of the Aérophile 
on February 18, 1897. Analysis of the air collected, by M. L. 
Cailletet. The vacuous reservoir was fitted with a special tap, — 
worked by a clock, so arranged as to open at one hour and a 
quarter after commencing the ascent, previous experiments 
haying shown that this corresponded with the maximum height. 
The results of the analysis showed that the composition of the 
air at these high altitudes (51,000 feet) is practically the same as 
on the ground. Observations on the subject of the preceding 
communication, by M. A. Miintz. The slight diminution in the 
oxygen found, and the slight increase in the carbonic acid, may 
possibly be due toa slight oxidation of the grease used to lubricate 
the tap.—M. G. Bonnier was elected a member in the Section of 
Botany, in the place of the late M. Trécul.—On the reduction 
of the general problem of integration, by M. Riquier.—Theorem 
on entire series, by M. Hadamard.—On the centres of gravity of 
surfaces parallel to a closed surface, by M. Ernest Duporeq.—On 
permanent deformation of glass, and displacements of the zero 
of thermometers, by M. L. Marchis. Experiments are cited 
showing that alternate heating and cooling of a thermometer is 
more efficacious in displacing the zero of a thermometer than 
long heating at a fixed temperature.—Application of the 
Rontgen rays to measure the electromotive force of contact, 
by M. Jean Perrin.—The action of phosphorus upon gold, 
by M. A. Granger. At a temperature of about 400° C. phos- 
phorus vapour combines with gold, forming a phosphide, Au,P4. 
To isolate this it is necessary to cool the tube rapidly, as the 
temperature limits between which the compound is stable are 
very narrow.—On the estimation of antimony in the state of 
peroxide, by M. H. Baubigny. Sb,O; is fairly stable at 357°, 
begins to lose oxygen at 440°, and leaves a constant residue of 
Sb,O04 at 800°, the purity of which was tested by dissolving: in 
hydrochloric acid in presence of potassium iodide, and weighing 
the antimony as the trisulphide.—Action of free bases on salts, by 
M. Albert Colson, From an experimental study of the replace- 
ment of diisobutylamine and piperidine by ammonia, it is con- 
cluded that the decomposition of ammoniacal salts by fixed 
bases is a phenomenon of heterogeneous dissociation. —On a 
