October io, 1901] 



NATURE 



587 



and his paper on the possibility of obtaining interference between 

 light from different sources had to be taken as read. Dr. 

 Stoney believes he has obtained undoubted experimental proof 

 of the possibility, but the matter must be held over till his proof 

 can be considered and discussed. 



Prof. Schuster gave an account of his experiments on the 

 passage of electricity through mercury vapour. They seem to 

 indicate that pure mercury vapour is a non-conductor. 



Prof. Minchin described the latest form of his photo-electric 

 cell, which consists of two selenium coated aluminium wires 

 dipping into certain solutions, and produces a measurable E. M. F. 

 when one wire is exposed to the light of a star. An arrange- 

 ment so sensitive should have a great future before it. 



In the meteorological department of the Section, papers 

 by Messrs. W. N. Shaw and R. W. Cohen, on the 

 effects of sea temperature and wind direction on the 

 seasonal variation of air temperature in these islands, were 

 read. The presence of the sea delays each seasonal 

 change of temperature, and the authors are investigating the 

 effect of the direction and temperature of the prevailing winds 

 on the air temperature at the four principal stations of the 

 Meteorological Otiice. Mr. F. X. Denison has found that the 

 depression of the earth's crust due to an area of high barometric 

 pressure can be detected by a seismograph at great distances from 

 the centre of the depression, the instrument being tilted towards 

 the area of high and from that of low pressure. The approach 

 of a barometric depression is therefore indicated by the seismo- 

 graph long before the barometer shows any sign of it. 



In the mathematical department, Prof. Mittag-Leffler com- 

 municated a paper on a criterion for recognising the irregular 

 points of analytic functions, an important extension of the 

 theory of convergent series of powers to convergent series of 

 functions. Mr. R. W. II. T. Hudson extended the idea of 

 Newton's diagrams to the theory of differential equations. 

 Prof. G. H. Darwin communicated a paper on Poincare's pear- 

 shaped figure of equilibrium of a rotating liquid, and Col. 

 Cunningham announced the discovery of certain high primes, 

 mainly by the use of the numbers called by Euler " idoneal." 

 Several new theorems dealing with idoneal numbers were an- 

 nounced by Col. Cunningham and the Rev. J. CuIIen. F'urther 

 papers dealt with modified proofs of propositions already known. 



In the astronomical department. Prof. Turner in his open- 

 ing address called attention to the need of cooperation in 

 astronomical work, cooperation which should not sink the in- 

 dividuality of the observer, or substitute routine for an alert 

 spirit of inquiry and investigation. Prof. G. Forbes brought 

 forward several facts which seemed to support his contention 

 that there is a planet beyond Neptune with a mass about equal to 

 that of Jupiter. Father Cortie announced that he had found the 

 faculce on the sun's surface followed the same law of rotation as 

 the spots, and Mr. Hinks showed that the objections which had 

 been raised to the determinations of the solar parallax from 

 photographs of Eros, on the ground that it was a moving object, 

 were unfounded. At the close of the sitting. Prof. Turner 

 announced that Prof. Pickering had succeeded in taking a photo- 

 graph of the spectrum of a lightning flash, and that important 

 information would be forthcoming when the photograph had 

 been measured. C. H. Lees. 



ZOOLOGY AT THE BRITISH ASSOCIATION. 

 'T'HURSDAV, September 12. — The president's address was 

 taken later than usual in order to afford opportunity of 

 attending some other sectional address. In the afternoon the 

 reports of committees and a few papers were taken, as 

 follows : — 



(i) Dr. Hepburn and Dr. D. Waterston gave a paper on the 

 pelvic cavity of the porpoise as a guide to the determination of 

 the sacral region in Cetacea. The chevron bones distinguish 

 the caudal vertebra; in cetaceans, but there is no easy method of 

 distinguishing sacral from lumbar vertebra;. The authors find 

 a true pelvic cavity in the porpoise which corresponds to five 

 pre-caudal vertebrae, and they suggest that these five vertebra; 

 are to be regarded as sacral in Cetacea. They find considerable 

 variation m the position of this sacral region in the different 

 Cetacea, which they consider to be due to differences in the 

 numbers of dorsal and lumbar vertebra; present. 



(2) Prof. R. J. Anderson, on the|reUationships of the premaxilla 

 in the bears. The premaxilla differs in the level and breadth of 



NO. 1667, VOL. 64] 



its articulation with the frontal, just as the nasals reach higher 

 up and further back in some bears than in others. Genera 

 allied to the bears approach them in regard to the relation of 

 the premaxilla to the frontal, so do sotiie of the Canidce, but to 

 a less degree, whilst other forms of the latter family have a wide 

 interval between the premaxill.T; and frontals. It is not difficult 

 to account for the enlarged premaxilla; of elephants, whales 

 and rodents, or for the short stout forms in Suids;, &c. ; but the 

 seals, while in some respects resembling the arctoids, differ much 

 in their premaxilla. The isolated centres met with in some 

 animals in the frontal region (e.g.. Gorilla, Ursits, Labistns) 

 are wormian. The separate bone found in connection with the 

 ventral part of the premaxilla in monotremes is not found in 

 other mammals. 



(3) Reports of Committees : — "On bird migration in Great 

 Britain and Ireland." — The committee expresses its most grateful 

 admiration of Mr. Eagle Clarke's invaluable services. Mr. 

 Eagle Clarke supplies detailed statements on the migrations of 

 the skylark and of the swallow, those of the former being of 

 an extremely complicated nature. 



"Index Animalium." — During the last year the period 1758- 

 iSoo has been dealt with. Arrangements had been made with 

 the Cambridge University Press to begin the work of printing 

 this first part of the Index in May, 190 1. The indexing of 

 iSoi-rgoo now continues. The whole of the work, as usual, 

 has been done by Mr. C. Davies Sherborn. 



Zoology of the Sandwich Islands. — This eleventh report 

 states that Mr. R. C. L. Perkins has been working during the 

 last year almost solely on the island of Oahu. The present 

 position of the work is discu-ssed. 



Coral Reefs of the Indian Regions. — Mr. J. Stanley Gardiner 

 has sorted out the marine collections from the Maldive and 

 Laccadive archipelagoes into groups for the specialists, and some 

 of these groups have already been worked up. The collections 

 seem very complete, and the committee asks for assistance in 

 publishing. 



Table at the Naples Zoological Station.— In addition to the 

 usual statistical information the committee give reports from 

 Dr. Reginald BuUer on the fertilisation process in Echinoidea, 

 and from Dr. Hamlyn- Harris on the statocysts of Cephalopoda. 

 Table at the Plymouth Marine Laboratory. — The occupation 

 of the table during the year is reported on. 



Natural History and Ethnography of the Malay Peninsula. — 

 Mr. W. W. Skeat gives an account {to Sections D, H and K) 

 of the Cambridge Exploring Expedition. An extensive collec- 

 tion of vertebrates was made, and the first two species of 

 Peripalus found in the Malay peninsula were discovered. These 

 latter have recently been described by Mr. R. Evans. 



Plankton Investigation. — .Mr. Garstang reports upon his 

 periodic work in the English Channel. 



On September 13 the following papers were taken :^ 

 (i) Mr. T- Stanley Gardiner, on the coral islands of the 

 Maldives.— The Maldive group to the south-west of Ceylon is 

 made up of a large series of comparatively shallow banks, 

 separated from one another by channels of about 170 fathoms in 

 depth. They extend north and south as a chain, double in the 

 centre, for 550 miles. All are covered with coral reefs, arising 

 to the surface. Some banks have on their circumferences the 

 single ring-shaped reefs of perfect atolls, while others are 

 studded with numbers of small isolated reefs, many of which are 

 of circular form with shallow lagoons (atoUons). The two 

 classes of bank merge into one another, and the changes, going 

 on at the present day, are such that the atolls may be supposed 

 to have arisen by the fusion of the smaller reefs. All land in 

 the group owes its origin directly or indirectly to elevation, and 

 in most atolls is very markedly washing away. Everything 

 points to a state of rest at the present day. The atoll reefs are 

 perfecting themselves on all sides, and passages are closing up. 

 The reefs, however, are not broadening, but to a certain point 

 narrow as they become more perfect. The central basins of 

 atollons are everywhere coming into free communication with 

 the lagoons of the atolls. There is no trace of the filling in of 

 the latter ; indeed, such evidence as was found pointed, on the 

 contrary, to their further widening and deepening and to the 

 gradual destruction of the shoals and lands within the encircling 

 reefs. The Maldive group marks the existence of an ancient 

 land-area, but the changes going on are not consistent with the 

 view that the reefs were formed on the subsidence of the land. 

 The various reefs appear rather to have grown up separately on 

 slight elevations of a common plateau at a depth of 150 fathoms, 



