January 3, 1901J 



NATURE 



243 



to Mr. C. Trubenbach, managing director in London, who for- 

 warded them to the author for examination. They consisted 

 of (i) boulders, (2) the diamantiferous rock (blue ground), 

 (3) country rock. (l) One angular specimen, a felsite or por- 

 phyrite, with fluxion structure, might be only a fragment of a 

 dyke or a flow ; the other eight were more or less water-worn. 

 All were holocrystalline igneous rocks, two being saxonites, two 

 varieties of Iherzolite, with a few garnets, one an enstatile-euly- 

 site, one an eclogite like those described last year, but without 

 any diamonds, one a hornblendic gabbro, exhibiting an interest- 

 ing micropegmatitic structure with felspar and pyroxene, and one 

 a diorite. (2) The blue ground presented a general resemblance 

 to that from the De Beers mines — the so-called kimberlite — but 

 its matrix contained a much larger amount of a minute, second- 

 ary brown mica. This matrix had been analysed by Mr. C. 

 James at University College, with the result that the CO2 

 and H,0 only amounted to 13 "55 per cent., the magnesia being 

 12 "14, and the other constituents showing that serpentine could 

 not, at most, form more than about 25 per cent, of the rock. This, 

 then, was yet another proof that the so-called kimberlite could 

 not be an altered peridotite, but was really, as the writer con- 

 tended, a breccia of rather variable composition. No diamonds 

 were observed this year in the boulders described, but Mr. 

 Trubenbach had obtained another specimen of a pyrope enclos- 

 ing a small but well-formed diamond. (3) The country-rock. 

 Of this the writer had examined, among others, a variety called 

 "bastard blue" by the miners, which had occurred above the 

 ordinary " blue" and was supposed by them to be related to it. 

 This, however, was not the case. It was a mudstone containing 

 little pebbles of diabase and, more rarely, of a microgranite and 

 a subcrystalline limestone. It was, however, interesting as show- 

 ing the existence of basic igneous rocks of Triassic or pre-Triassic 

 age. Besides that, and the additional evidence as to the nature 

 of the blue ground, this investigation brought the number of 

 species or strongly-marked varieties of holocrystalline rocks 

 which occur as boulders more or less waterworn up to seven at 

 the very least. The author was of opinion that the most en- 

 thusiastic advocate of concretionary action would now be obliged 

 to admit that the specimens, two of which, described in his last 

 paper, had contained diamonds, were rock fragments which had 

 been shaped by the action of water. 



Mathematical Society, December 13, 1900.— Dr. Hobson, 

 F.R.S., President, in the chair. — Mr. Basset, F.R.S., spoke on 

 the real points of inflexion of a curve. — Miss Barwell read a 

 paper entitled, " On the conformal representation of polygons on 

 a half plane." — Prof. Elliott, F.R.S., communicated his own 

 paper, " The syzygetic theory of orthogonal Binariants," and gave 

 an account of a paper by Mr. A. L. Dixon entitled "An addition 

 theorem for hyperelliptic functions." — The following papers were 

 communicated by their titles : On some properties of groups of 

 odd order, ii., Prof. Burnside, F.R.S. — On discriminants and 

 envelopes of surfaces, Mr. R. W. Hudson. — Note on the in- 

 flexions of curves with double points, Mr. H. W. Richmond. 



Zoological Society, December 18, 1900.— Dr. A. Giinther, 

 F.R.S., Vice-President, in the chair. — The Secretary exhibited, 

 on behalf of Major A. St. Hill Gibbons, the skull and horns of 

 a white rhinoceros [.Rhinoceros simus?) from the White Nile, 

 and the mounted heads of two species of Topi antelopes, which 

 had been procured by Major Gibbons during his recent journey 

 through Africa from south to north. — The Secretary also 

 exhibited, on behalf of Sir Harry Johnston, K.C.B., some 

 pieces of skin of an apparently new species of zebra which had 

 been ascertained to inhabit the forest on the banks of the 

 Semleki River near the borders of the Uganda Protectorate. — A 

 communication was read from Capt. Stanley S. Flower, contain- 

 ing an account of the animals he had obtained or observed during 

 Sir William Garstin's expedition to the White Nile. Amongst 

 these were examples of several rare species of antelopes, such 

 as the white-eared kob ( Cobus leucotis) and Mrs. Gray's kob 

 {Cobus maria), and numerous specimens of the shoe-bill or 

 whale-headed stork {Balaeniceps rex). — A communication was 

 also read from Mr. W. Malcolm Thomson containing an 

 account of a large branchiate polynoid {Lepidonotus gigattteus 

 Kirk) from New Zealand. — A communication from Mr. H. M. 

 Kyle (of St. Andrews, N.B. ), contained a description of a new 

 genus and species of flat-fishes from New Zealand, under the 

 name Apsetta thompsoni. — Dr. A. G. Butler contributed a paper 

 on the butterflies lately collected, and presented to the British 



NO. 1627, VOL. 63] 



Museum, by Lord Delamere. The specimens had been 

 obtained chiefly near Mount Kenya, in British East Africa, and 

 had been referred by the author to seventy-nine species, which 

 were enumerated in the paper. — Prof. D'Arcy W. Thompson, 

 C.B. , exhibited and described a large specimen of a cuttle-fish 

 {Ancistroteuthis robusta Steenstrup) from Unalaska. The 

 generic position of this cuttle-fish had previously been uncer- 

 tain, owing to the absence of knowledge of the tentacular club. 

 This was now described for the first time, and confirmed 

 Steenstrup's provisional identification. — Mr. F. E. Beddard, 

 F.R. S., described a new species of earthworm under the name 

 of Amyntas alexandri. The specimen had been sent to him 

 from Kew Gardens, whither it had been imported from the 

 neighbourhood of Calcutta. 



Paris. 



Academy of Sciences, December 24, 1900. — M. Maurice 

 Levy in the chair. — Formulas and tables for calculating the 

 times and heights of high and low water, the heights from hour 

 to hour being known, by M. E. Guyou. The heights for three 

 consecutive hours being known, a very simple formula is given 

 for calculating the time of high water. — On the origin of 

 chemical combination and ' the combination of silver with 

 oxygen, by M. Berthelot. Silver foil, heated with oxygen in 

 sealed tubes at varying temperatures, is slightly attacked, some 

 argentous oxide being formed and the silver becoming different 

 in appearance. This action commences at a temperature of 

 about 200° if the time of heating is very prolonged, and becomes 

 very appreciable at 500°-550° C. If the oxygen is replaced by 

 steam or carbon dioxide the silver is absolutely unchanged. — 

 Silver and carbon monoxide, by M. Berthelot. Silver foil, after 

 four hours heating with dry carbon monoxide at 500°-550°, be- 

 comes chaniied in appearance, and some three to four per cent, 

 of the gas disappears, carbon being deposited and carbon di- 

 oxide produced. — Hydrogen and silver, by M. Berthelot. 

 Hydrogen, heated with silver at 550° in a sealed tube, behaves 

 differently from nitrogen, steam or carbon dioxide, as the metal 

 alters considerably in appearance. It is possible that a com- 

 pound is formed analogous to sodium hydride. — On the theorem 

 of Hugoniot and some analogous theorems, by M. P. Duhem. — 

 The first sign of life, by M. Augustus D. Waller. Following 

 up some researches on the last sign of life, it results that if a 

 blaze is the last sign it should also be the first. Some experi- 

 ments with hens' eggs confirm this view. — On congruences of 

 which the two focal pencils are cyclic, by M. C. Guichard. — 

 The homographic compass, realising by articulations general 

 plane homography, by M. G. Koenigs. — On Neumann's 

 method of the arithmetical mean, by M. W. Stekloff. 

 — On a series relating to a theory of a linear differential 

 equation of the second order, by M. A. Liapounoff. — On 

 the theta functions of three variables, by M. M. Krause. — The 

 theorem of vortices in thermodynamics, by M. Jougnet. — 

 Permanent modifications of metallic wires and their electrical 

 resistance, by M. H. Chevallier. The same wire is submitted to 

 a series of heatings, which are alternately fixed and oscillating, 

 and the variations of resistance measured. It was found that 

 the permanent variations of resistance are greater when the 

 temperature is oscillating than when it is fixed. — On the electro- 

 motive force of magnetisation, by M. Rene Paillot. It has 

 been shown by M. Hurmuzescu that in a battery formed of two 

 electrodes of iron, one of which is magnetised, the latter 

 becomes positive with respect to the non-magnetised one. 

 These experiments have now been extended to much stronger 

 fields, 30,000 units, and it is found that for a given specimen of 

 iron and acid the electromotive force of magnetisation tends 

 always to a fixed limit. — The luminescence of a rarefied gas 

 round metallic wires communicating with one of the poles of 

 an induction coil, by M. J. Borgmann. — An apparatus allowing 

 several physiological applications of the light produced by an 

 incandescent lamp, by MM. Foveau de Courmelles and G. 

 Trouve. An application of parabolic mirrors. — On the lique- 

 faction of gaseous mixtures. The isotherms of a mixture, by 

 M. F. Caubet. A discussion of results obtained with mixtures 

 of carbon dioxide and sulphurous acid, and of carbon dioxide 

 with methyl chloride. — A contribution to the study of rarefied 

 gases, by M. Albert Colson. — Influence of pressure on the 

 phenomena of chemical equilibrium, by M. O. Boudouard. A 

 description of some experiments upon the formation of carbon 

 monoxide from carbon dioxide and charcoal. — On the selenides 

 of copper, by M. Fonzes-Diacon. Some new methods of pre- 



