May 15, 1879] 



NATURE 



71 



tinfoil of unequal size placed near the ends of the tube and me- 

 tallically connected, and others with a strip of tinfoil placed 

 along the tube, all gave effects showing that the discharge cannot 

 be simultaneous throughout the tube. The phenomena appear 

 to require for their interpretation that, in front of the pulse 

 coming from the (positive) air-spark terminal, there is, during 

 the interval between the pulses, a rising negative potential, 

 'i'his is entirely swept out by the pulse as it advances along the 

 lube, after which the process is repeated. The condition of 

 things behind the pulse is more dilhcult to determine, but an 

 experiment with the telephone gives reason to think that parts of 

 the tube nearer to the non-air-spark end are in a condition 

 to demand relief, before those nearer to the air-spark terminal 

 have ceased to require it. And on this account the discharge 

 ■ may, perhaps, be more nearly represented by a lazy tongs than 

 by a bullet. 



How far the results obtained from the sensitive state are ap- 

 plicable to ordinary discharges is a question which cannot yet be 

 definitively answered. But the marked similarities in the pheno- 

 mena, and the predisposing circumstances of striation or non- 

 striation, as well as in the terminal peculiarities of the two kinds 

 of discharge, point strongly to the conclusions that all vacuum 

 •discharges are^disruptive'; and that sensitive differ from non-sensi- 

 tive discharges mainly in the scale of the discontinuity due to the 

 disruptiveness, causing a difference between the two classes of 

 phenomena analogous to that between impulsive and continuous 

 forces in dynamics. 



Mathematical Society, May 8.— Mr, C. W. Merrifield, 

 F.R.S., president, in the chair. — Messrs. A. J. C. Allen and E. 

 Anthony were elected Members. — The following communications 

 were made : — On the complex whose lines join conjugate points 

 of two correlative planes. Dr. Hirst, F.R.S. — Note on a geo- 

 metrical theorem connected with the function of an imaginary 

 variable. Prof. Cayley, F.R.S. — Some definite integrals, the late 

 Prof. Clifford, F.R.S. — A method of constructing, by pure 

 analysis, functions X, Y, Sec, which possess the property that 

 yX Yd a = o, and such that any given function can be expanded 

 in the form aX \ &Y ■\- y Z + . . ., Mr. E. J. Routh, F.R.S. 

 — The numerical calculation of a class of determinants, and a 

 continued fraction, Mr. J. D. H. Dickson. — On the inscription 

 of the regular heptagon, Rev. Dr. Freeth. 



Zoological Society, May 6. — Prof. W. H. Flower, 

 F.R.S., president, in the chair. A letter was read from 

 Mr. E. L. Layard, F.Z.S., relating to the localities of certain 

 species of Fruit-Pigeons (Plilopus) of the South Pacific 

 Islands. — Prof. Flower, F.R.S., exhibited and made remarks 

 on a drawing of a British Cetacean {Delphinus tursio), 

 taken from a specimen captured near Holyhead in 1878. — 

 A communication was read from Mr. Gerard Krefft, giving the 

 description of a supposed new form of insectivorous Bat, of 

 which a specimen had been obtained on the Wilson River, Central 

 Queensland.— The Rev. Canon Tristram, C.M.Z.S., read a jle- 

 scription of a new species of Wood-pecker, from the Island of 

 Tyzu Sima, near Japan, which he proposed to name after its 

 discoverer, Dryocopus richardsi. — A communication was read 

 from Mr. F. Moore, F.Z.S., containing the descriptions of new 

 genera and species of Asiatic Lepidoptera Heterocera. Eleven 

 new genera were characterised and ninety new species described. 

 — Mr. G. French Angas, C.M.Z.S., read the descriptions often 

 new species of shells of the genera y4jriK(F3 and Patunculus. — 

 A communication was read from Mr. W. A. Forbes, F.Z.S., on 

 the anatomy of the African Elephant, based on the facts 

 observed during a dissection of a young female of that species 

 during the last winter. The structures of the thoracic, alimen- 

 tary, and urino-genital viscera of this species were described, 

 and compared with the previously published accounts of those 

 of both the Indian and African species of Elephant. The most 

 important differences observed were those displayed in the liver 

 and female organs, but on the whole were not of such a nature 

 as to make it advisable, in the author's opinion, to separate 

 Loxodon as a genus from Elephas proper. — A paper was read 

 by Mr. F. Jeffrey Bell, F.Z.S., on the question of the number 

 of anal plates in the Echiuoderms of the genus Eckinocidaris. 



Geological Society, April; 30.— Henry Clifton Sorby, 

 F.R.S., president, in the chair. — Alfred Stanley Foord was 

 elected a Fellow of the Society. — The following communications 

 were read : — A contribution to the history of mineral veins, by 

 John Arthur Phillips, F.G.S. In this paper the author described 

 ■the phenomena of the deposition of minerals from the water and 



steam of hot springs, as illustrated in the Californian region 

 referrmg especially to a great " sulphur bank " in Lake County 

 to the steamboat springs in the State of Nevada, and to the great 

 Comstock lode. He noticed the formation of deposits of silica 

 both amorphous and crystalline, inclosing other minerals, espe- 

 cially cinnabar and gold, and in some cases formini; true mineral 

 veins. The crystalline silica formed contains liquid-cavities, 

 and exhibits the usual characteristics of ordinary quartz. In the 

 great Comstock lode, which is worked for gold and silver, the 

 mines have now reached a considerable depth, some as much as 

 2,660 feet. The water in these mines wus always at a rather 

 high temperature, but now in the deepest mines it issues at a 

 temperature of 157° Fahr. It is estimated that at least 4,200,000 

 tons of water are now annually pumped from the w orl-ings ; and 

 the author discussed the probable source of this heat, which he 

 was inclined to regard as a la.st trace of volcanic activity. — Vec- 

 tisaurus valdensts, a new Wealden Dinosaur, by J. W. Hulke, 

 F.R.S. The characters presented by the genus Vi^cSisaurus were 

 stated to be as follows : — Ilium with a long compressed ant- 

 acetabular process, having its greatest transverse extent in a 

 vertical plane, and strengtheiiCd by a strong rid.e produced from 

 the sacral crest. Vertebrfe in anterior dorsal region having opis- 

 thocoelous centres, their lateral surfaces longitudinally concave, 

 transversely gently convex, meeting below in a blunt keel. — On 

 the Cudffegong diamond-field, N.S.W., by Mr. Norman Taylor. 

 — On the occurrence of the genus Diihyroiaris in the lower 

 carboniferous, or calciferous sandstone series of Scotland, and 

 on that of a second species of Anthrapalamon in these beds, 

 by R. Etheridge, Jun., F.G.S. 



Cambridge 

 Philosophical Society, May 5. — A communication was 

 made to the Society by Prof. T. McK. Hughes, on the relation 

 of the appearances of life upon the earth to the known breaks in 

 the continuity of the older sedimentary rocks. In his introduc- 

 tory remarks the author explained the manner in which he be- 

 lieved the transference of the area of the growth of sediment 

 took place by gradual depres-ion on one side and elevation on 

 the other, and pointed out that there was stratigraphical evidence 

 of the earlier commencement of the accumulation of a continuous 

 series in one area than another, and that often the direction of 

 the movements could be inferred. To the compulsory migration 

 of species consequent upon these movements he attributed the 

 extinction of those that could not adapt themselves to the new 

 circumstances, the appearance of the colonies described (>y Bar- 

 rande, and also the gradual introduction of new forms of life 

 throughout the whole of the sedimentary rocks. The principal 

 part of the paper was upon the last question, the author holding 

 that it was only reasoning in a circle to define formations palaeon- 

 toloi;ically and then to speak of the incoming and outgoing of 

 species as nearly coincident with the beginning and end of the 

 formation. He classified the whole sedimentary series on the 

 principle of grouping together all the sediment continuously de- 

 posited in any one area, and indicated by corresponding intervals 

 the period during which there was in that area denudation only, 

 the deposition of the denuded material necessarily going on else- 

 where. Then, giving an analysis of the palaeontology of the 

 older rocks, he showed that the various forms of life came in 

 gradually as compelled to move, and as their travelling powers 

 allowed them, from adjoining areas where local conditions had 

 become unfavourable, pointing out that they did not generally 

 first appear at the be^jinning or disappear at the close of any 

 series of continuous deposits, but that new forms kept turning 

 up all thr ugh, and that after a long interval, « hether measured 

 by denudation or deposition, about the same kind and amount 

 of pala.ontological change had occurred, the chances being that 

 in so long a time geographical changes had talen place in the 

 surroundmg district. lie showed that thus the pa seontological 

 confirmed the strati^aphical evidence with regard to the per- 

 sistence of continental as well as of oceanic areas, as he sequence 

 of life on the earth required that there could never have been an 

 inteiTuptinn in the continuity of suitable land and water. He 

 appealed to physicists to tell us whether chielly to he transfer- 

 ence of such great masses of material always to le coast lines 

 of continents, or to secular cosmical action, or to both, we should 

 refer this persistent creeping of earth folds in various directions 

 at different times, 



Paris 



Academy of Sciences, April 28. — M. Daubr^e in the chair. 

 — The following papers were read : — On the electric light, 



