June 12, 1919] 



NATURE 



299 



is found that the assumption which best agrees with 

 experimental evidence is that the external action of 

 the atom which is electro-positive is eqrivalent to a 

 doublet and a positive charge both situated within the 

 atom. — Prof. W. Peddie : The thermo-dynamics of 

 unstable states. It was pointed out that, although 

 the usual thermo-dynamical definition of absolute 

 temperature applies in all practical cases, the second 

 definition, recently indicated by Sir Joseph Larmor as 

 formally satisfying Carnot's conditions, has an in- 

 teresting theoretical application in the case of unstable 

 states of the working substance. 

 Paris. 

 Academy of Sciences, May 19. — M. Leon Guignard in 

 the chair. — G. Humbert : The measure of classes of 

 ternary positive quadratic forms of given determinant. 

 — A. Gautier : The influence of fluorides on vegetation. 

 Preliminary trials in garden-pots. Of twelve species 

 cultivated under similar conditions, with and without 

 addition of fluorides, seven showed increased growth 

 In presence of fluorides, three were indifferent, and 

 three gave lower yields.— C. Guichard : A mode of 

 generation of isothermal surfaces with plane lines of 

 curvature in a system. — M. Tilho : A scientific expedi- 

 tion of the Institute of France in Central Africa 

 (Tibesti, Borku, Ennedi). — M. Edouard Goursat was 

 elected a member of the section of geometry in succes- 

 sion to M. Emile Picard, elected permanent secretary. — 

 G. Jnlia : Integral or meromorphic functions. — E. 

 KogbetUantz : The developments of Jacobi. — H. 

 Muraour : The determination of temperatures reached 

 in explosive reactions. Both the methods in use pre- 

 suppose that the composition of the gases at the 

 moment of explosion is known. The temp>erature 

 determined varies according as the methane is assumed 

 to exist at the moment of explosion or to be formed 

 during t|;ie cooling. Experiments with a modified 

 bomb are described, and these prove that the greater 

 part, if not the whole, of the methane is formed during 

 the cooling period. — M. H. Robert : A new laboratory 

 form of fractionating column and the measurement 

 of its efficiency. The lower part of the column, a 

 diagram of which is given, is vacuum-jacketed, whilst 

 a similar upper column is cooled externally by a con- 

 trolled air-current; the thermometer is surrounded by 

 a vapour-jacket. Examples of the remarkable effici- 

 ency of the column are given. Pure hexahj^drotoluene 

 was isolated from Borneo petrol ; pentane, hexane, 

 and heptane from American petrol ; acetic anhydride 

 from its mixture with acetic acid. — G. Claude : An 

 important consequence of the commercial synthesis of 

 ammonia. Ammonium chloride has been proved by 

 Georges Ville to be capable of replacing ammonium 

 ■sulphate as a manure, and carries a higher percentage 

 of ammonia. If in the ammonia-soda process the 

 sodium bicarbonate and ammonium chloride are col- 

 lected separately, the latter is available as manure, 

 the chlorine of the salt is utilised, and the consump- 

 tion of sulphuric acid avoided. — P. Lesage ; The 

 stabilisation of characters in plants grown in presence 

 of salt. — H. Coupin : The place where water is 

 absorbed by the root. From experiments detailed the 

 conclusion is drawn that the root absorbs water ex- 

 clusively through its tip, and not through the root- 

 hairs. — M. Dallorl : The Coal Measures on the coast 

 of the province of Oran. — J. Levine : Two hundred 

 and twenty ye&rs of (meteorological) observations in 

 Paris. — G. Liisk : The comparative calorimetry of the 

 ingestion of meat, lactic acid, and alanine in the 

 animal. — A. L. Herrera : The pseudo-organisms of 

 calcium fluosilicates.— E. Bourquelot and M. Bridel : 

 The biochemical synthesis of cellobiose with the aid 

 of emulsin. — E. Kohn-Abrest : Apparatus for the rapid 

 analysis of confined air and unhealthy atmospheres. 

 NO. 2589, VOL. 103] 



Cape Town. 

 Royal Society of Soutli Africa, April 16. — Dr. J. D. F. 



Gilchrist, president, in the chair. — J. R. Sutton: Some 

 controversial notes on the diamond. The author dis- 

 cusses the spontaneous breaking of diamonds and re- 

 affirms his previous conclusions on the subject. It is 

 claimed that there is no fundamental difference of 

 process between the spontaneous breaking of a pure 

 colourless crystal containing an inclusion of foreign 

 mineral and that of opaque or clouded diamond. The 

 probable derivation of distorted diamonds (pseudo- 

 cleavage) from groups and clusiters is also considered. 

 The hardness of the diamond is generally over- 

 estimated. 



Calcutta. 

 Asiatic Society of Bengal, May 7. — N. Annandale and 

 H. G. Carter: Notes on the vegetation of Seistan. 

 The paper is based primarily on a collection of plants 

 made, mainly in desert country and in the Hamun-i- 

 Helmand or lake basin of Seistan, in November and 

 December, 1918. A list of these plants is given and 

 an attempt made to estimate the more conspicuous 

 characters of the vegetation of several different types 

 of environment, viz. the stony desert, the alluvial 

 plain, the banks of streams of saline water, and the 

 Hamun. Among the more interesting points brought 

 out are the correlation between conspicuous colours 

 and poisonous qualities in the plants of the desert, 

 the different effects of soluble salts on the growth of 

 different grasses, and the production of stiff, bayonet- 

 like leaves in the same group in halophytic conditions. 



BOOKS RECEIVED. 



Mathematical Papers for Admission into the Royal 

 Military Academy and the Royal Military College and 

 Papers in Elementary Engineering for Naval Cadet- 

 ships for the years 1909-18. Edited by R. M. Milne. 

 (London : Macmillan and Co., Ltd., 1919.) 7s, 



The Principles of Electric-Wave Telegraphy and 

 Telephony. By Prof. J. A. Fleming. Fourth edition, 

 revised. Pp. xvi + 707 + plates vii. (London : Long- 

 mans, Green, and Co., 1919.) 42^. net. 



Mammalian Physiology : A Course of Practical 

 Exercises. By Prof. C. S. Sherrington. Pp. xi + 

 156 + plates ix. (Oxford: At the Clarendon Press, 

 1919.) i2s. 6d. net. 



Soils and Manures in New Zealand. By L. J. Wild. 

 Pp. 134. (Auckland and London : Whitcombe and 

 Tombs, Ltd., 1919.) 2s. 6d. 



The America of To-day : Being Lectures Delivered 

 at the Local Lectures Summer Meeting of the Uni- 

 versity of Cambridge, 1918. Edited by Dr. G. 

 Lapsley. Pp. xxv+254. (Cambridge : At the Uni- 

 versitv Press, 1919.) 125. net. 



The Evolution of the Dragon. By Prof. G. Elliot 

 Smith. Pp. xx+234. (Manchester: At the Univer- 

 sity Press; London: Longmans, Green, and Co., 

 1919.) JOS. 6d. net. 



The Chemists' Year-Book, 1918-19. Edited by 

 F. W. Atack, assisted by L. Whinyates. Vol. i., 

 pp. vi+422; vol. ii., pp. iv + 423-1 146. (London and 

 Manchester: Sherratt and Hughes, 1919.) 155. net 

 two vols. 



Studies in the Construction of Dams : Earthen and 

 Masonry. Arranged on the Principle of Question and 

 Answer' for Engineering Students and Others. By 

 Prof. E. R. Matthews. Pp. v + 43. (London : Charles 

 Griffin and Co., Ltd., 1919.) 4.^'. (id. net. 



National and International Right and W'rong : 

 Two Essavs. Bv Henrv Sidgwick. With a preface 

 bv the Right Hon. Viscount Bryce. (Reprinted from 



