502 



NATURE 



[March 24, 1898 



rock is almost completely converted into a mass of very small 

 rhombohedra, the organic structures being nearly obliterated ; 

 while a preliminary chemical examination seems to indicate that 

 magnesia has been introduced into the rock to a considerable 

 extent. The complete study, microscopical and chemical, of all 

 the stages of the change which has taken place in this rock — a 

 study which will be undertaken by Mr. C. G. Cullis — promises 

 to throw much light on processes of rock-formation of very great 

 interest to the geologist. — Note on Clipperton atoll, by Rear- 

 Admiral Sir W. J. Wharton, K.C.B., F.R.S. This atoll, 600 

 miles from North America, in lat. 10^ 17' N., long. 109° 13' W., 

 possesses a lagoon which is now completely cut off from the sea. 

 In this is a perfectly round hole where soundings of 20 fathoms 

 or more are reported, on the authority of Mr. Arundel, and even 

 deeper ones on that of the captain of a merchant-vessel. On 

 the coral ring there rises a mass of modified trachyte, the subject 

 of the following communication, about 60 feet in height. The 

 great depth of the lagoon and the rock-mass on the ring are not 

 compatible with the origin of the reef by subsidence or outward 

 growth ; and the possible hypothesis is put forth that this reef 

 had grown on the lip of a volcanic crater, or on an island, such 

 as Krakatao, in which the interior has been enlarged and 

 deepened by volcanic explosion. — A phosphatised trachyte from 

 Clipperton atoll, by J. J. H. Teall, F.R.S. Specimens from the 

 projecting rock described in the preceding communication are 

 dark brown, white, or cream-coloured. The brown specimens 

 are trachytes, composed of glassy phenocrysts of sanidine set in 

 a groundmass of microlitic felspars with brown interstitial matter. 

 The light-coloured rocks are more or less altered trachytes, in 

 some of which the glassy phenocrysts of sanidine may still be 

 recognised. Analyses of several specimens show that the rocks 

 all contain varying amounts of phosphoric acid. — The Pliocene 

 deposits of the East of England, Part i. the Lenham Beds and 

 the Coralline Crag, by F. W. Harmer. From the discussion of 

 lists of fossils, a large number of sections, and a series of borings, 

 the author endeavours to establish a number of propositions with 

 regard to the Lenham Beds, the Coralline Crag, and the Red 

 'Crag. His evidence indicates that the Lenham Beds are older, 

 perhaps considerably so, than the Coralline Crag. 



Mathematical Society, March 10. — Prof Elliott, F.R.S. 

 President, in the chair. — Mr. A. N. Whitehead read a 

 paper on the geodesic geometry of surfaces in non-Euclidean 

 space. — Prof. W. Burnside followed with a paper on linear 

 homogeneous continuous groups whose operations are permut- 

 able. — Mr. T. I. Dewar, in the absence of Prof. Greenhill, 

 F.R.S., exhibited, with the aid of stereoscopes, some stereoscopic 

 diagrams of pseudo-elliptic catenaries and geodesies. — Lieut. - 

 Colonel Cunningham, R. E., contributed a supplementary note 

 on Aurifeuillians. — The President briefly brought before the 

 meeting a paper, by Mr. W. F. Sheppard, on the calculation of 

 the sum of the w/th powers of a large number of magnitudes, 

 and then (Lieut. -Colonel Cunningham in the chair) read a paper 

 by himself, on the transformation of linear partial differential 

 operators by extended linear continuous groups. 



Zoological Society, March 15. — Dr. Albert Giinther, 

 F.R.S., Vice-President, in the chair. — A communication from 

 Sir Edmund Loder, Bart., contained copies of some photographs 

 of the Beaver-pond at Leonardslea, Horsham, and gave a short 

 -account of the habits of the animals as there observed. — Mr. R. 

 E. Holding exhibited a pair of horns of the Sunga or Galla Ox 

 of Abyssinia, and made some remarks on the horns of this and 

 ■other varieties of the humped cattle of India and Africa. — A 

 ■communication from Dr. G. Stewardson Brady, F.R.S., on 

 new or imperfectly-known species of Ostracoda, chiefly from 

 New Zealand, was read. It contained descriptions of the 

 Ostracoda collected in New Zealand by Mr. H. Suter, for the 

 Zoological Museum of Copenhagen, and by Mr. G. M. 

 Thomson, of Dunedin. It also included a description of an 

 Ostracod from the Bay of Bengal, presenting some remarkable 

 peculiarities of the mouth-organs, and constituting the type of 

 a new genus, which was proposed to be called Eupathisloiiia. 

 Of the New Zealand species treated of sixteen were described as 

 new, and the new generic term Trachyleberis was proposed for 

 the reception of Cy there scabrocuneata, Brady. — Mr. E. H. J. 

 Schuster described a new species of flagellate Protozoan, which 

 he proposed to name Lophonionas sulcata. This species 

 occurred as an endo-parasite in the upper part of the colon of 

 Blatta americaira, Liun. — Mr. J. T. Cunningham read a paper 

 on the early post-larval stages of the Common Crab {Cancer 



NO. 1482, VOL. 57] 



pa^tirtts), and pointed out the affinity of that species with the 

 Circular Crab {Atelecyclus heterodon). — Mr. Oldfield Thomas 

 read a paper on some mammals collected by the late Mr. Henry 

 Durnford in 1877-8 in Chubut, Patagonia. — Mr. Martin Jacoby 

 contributed an addition to our knowledge of the phytophagous 

 Coleoptera of Africa by describing forty-three new species of the 

 groups Halticince and Galeructnce, specimens of which had been 

 collected by Mr. Guy A. K. Marshall in Mashonaland and 

 West Africa. Two new genera, viz. Cheiridisia and Pseude- 

 djisia, were characterised. 



Royal Meteorological Society, March 16.— Mr. F. C. 

 Bayard, President, in the chair. — A lecture on photographing 

 meteorological phenomena was delivered by Mr. A. W. Clayden, 

 who gave details of his experiences as Secretary of a Committee 

 of the British Association. After referring to the extreme value 

 of photographic methods of recording the movements of instru- 

 ments, the lecturer spoke of the real importance of preserving 

 photographic records of all sorts of unusual meteorological 

 phenomena, and emphasised the necessity of companion photo- 

 graphs showing the same scene under normal conditions. It 

 was suggested that meteorologists throughout the country should 

 co-operate with the Royal Meteorological Society in securing 

 such records. The phenomena of the lightning discharge, as 

 distinguished from those of a single flash, were next described 

 and illustrated by a number of lantern slides. Some of the 

 puzzles offered by lightning photographs were next alluded to, 

 and the lecturer stated that he had repeatedly found that a single 

 discharge lasted several seconds. Mr. Clayden then spoke ot 

 the "black" flashes shown in photographs, and described the 

 steps by which, some years ago, he was led to the proof that 

 they were merely a photographic phenomenon, but one which 

 still remains unexplained. Passing on to a consideration ot 

 cloud photography, the various methods in use were explained 

 and a large number of lantern slides were exhibited, in some of 

 which the clouds were shown on a background of blue sky in 

 nearly their natural colours, a result obtained by the employ- 

 ment of suitable developers on a specially prepared plate. The 

 method employed at Exeter by the lecturer for the measurement 

 of cloud altitudes was fully described. This differs from all 

 other methods in using the sun as a reference point. Mr. 

 Clayden then spoke of the difficulty in getting good pictures of 

 cirrus clouds, and described the methods dependent on the 

 polarisation of the blue light of the sky, but expressed a con- 

 viction that polarisation had nothing to do with their efficiency, 

 which was really due to a general lessening of brightness which 

 enabled the exposure to be properly judged. 



Cambridge. 



Philosophical Society, February 7. — Prof Newton, Vice- 

 President, in the chair. — " The coral reefs of Funafuti, 

 Rotuma, and Fiji, together with some notes on the structure 

 and formation of coral reefs in general," J. Stanley Gardiner. 

 The author had accompanied Prof. Sollas' expedition to Funa- 

 futi in 1896. Funafuti cannot be regarded as a typical atoll, as 

 it shows an elevation of at least 10 feet. Its islands are the 

 remains of the original reef, and are rapidly being washed away; 

 while the present reef is extending outwards by nullipore 

 growth, forming masses outside and joining them on to the rim. 

 In Viti Levu, Fiji, soft limestone attains an elevation of 900 

 feet and alternates with " soapstone," which the author regards 

 as a shallow water deposit analogous to the sand covering the 

 inner reefs round Viti Levu. Many of the islands of Lau are 

 of hard limestone, and represent raised atolls. In the case of 

 Vatu Vara a vertical thickness of 1030 is attained. Evidence is 

 given to show that the Fiji Group has been stationary for a long 

 period, and that the conditions and formation of its reefs strongly 

 oppose the subsidence theory. It is also contended that reefs 

 spread outwards on their own talus, while lagoons are formed by 

 solution. Evidence for the latter is given from the washing 

 away of the limestone islands of Lau, the atoll-reefs of which 

 are considered to have been formed by this means. The form- 

 ation of coral reefs is due rather to nullipore than coral growth, 

 and depends largely on the depth to which light can penetrate 

 sea water. — "Methods for the demonstration of- 'connecting 

 threads ' in the cell-wall," Walter Gardiner. The author gives 

 further details of his " Kolossow-Safranin " method, and de- 

 scribes a modification of Meyer's method, which he calls the 

 " iodine-acid violet " method. The paper also deals with the" 

 theorv of both of the above modes of investigation. 



