474 



NATURE 



[December 23, 1915 



processes. In this connection note has to be made of 

 the distinct line of demarcation between colloidal and 

 non-colloidal clay, the former state being inimical to 

 filtration processes generally. After studying the 

 various phenomena of the effect of weathering, ad- 

 sorption and absorption of metals and of water during 

 dressing and milling operations, their influence on 

 specific gravity and the effect of heat on clay, the 

 author deals with the viscosity of clay, its influence, 

 and the use and value of electrolytes. He adduces from 

 the facts premised in his investigation the highly 

 absorptive properties of colloidal as compared with 

 non-colloidal clay, and the powers which clays possess 

 of retaining liquids and dissolved salts, and he draws 

 the following conclusions : — (a) Adsorption of gold solu- 

 tion may occur during treatment, but the main loss 

 is probably due to absorption. This conclusion is 

 strengthened by the fact that (i) non-colloidal clay is 

 only slightly absorbent; (2) colloidal clay is highly 

 absorbent; and (3) burnt clay (i.e. after the colloidal 

 envelope has been destroyed) is practically non- 

 absorbent; (fc) the weathering of clay slime should be 

 avoided except in the instance where the decomposition 

 of refractory mineral is desired ; (c) clay slime should 

 be allowed an extended time of contact with wash 

 solutions. This precaution is, of course, unnecessary 

 if the ore has been roasted before cyanide treatment. — 

 E. Maxwell-Lefroy : Wolframite mining in the Tavoy 

 District, Lower Burma. This is an informing paper 

 dealing with the chief mineral product of the district. 

 Nearly one-fifth of the total world's output of wolfram 

 comes from Tavoy, so that particulars of the occur- 

 rence and methods adopted for mining and marketing 

 the mineral should be of interest. 



Paris. 

 Academy of Sciences, December 6.— M. Ed. Perrier in 

 the chair. — Ch. Fremont : A clock escapement of the 

 thirteenth century. The description is taken from a 

 manuscript dating between 1240 to 125 1, by a French 

 architect, Villard de Honnecourt. It is more than a 

 century earlier than the clock made by Henri de Vic 

 for Charles V., about 1370. — G. Moch : The double 

 detonation of projectiles possessing a high initial 

 velocity. Remarks on a communication on the same 

 subject by M. Agnus, with references to earlier dis- 

 cussions of the phenomenon. — P. Le Roland and A. 

 Carpentier : An induction Apparatus for detecting 

 metallic fragments. — Louis Malctes : Electrical influ- 

 ence in a cell with an insulating wall, and with liquid 

 nucleus.— L. Wertenstein : The charge of the radio- 

 active recoil.— L. Tschugaeff and W. Khlopine : The 

 series of hydroxo-platlnic salts. The new series is 

 prepared by the action of ozone on Peyrone's chloride 

 (NH3)2PtCl2, in presence of ammonium carbonate. 

 The general formula is [Pt.sNH3(OH)]X^ where X 

 is CI, (NO.,),_ etc. These substances have the property 

 of forming Insoluble carbonates and sulphates, and 

 resemble barium salts in this respect. — M. Fleury : The 

 subterranean hydrology of Alvlella. — A. Gnepin : Re- 

 sults of a shell wound "of the brain. Surgical ablation 

 or destruction of a third of the left cerebral hemisphere 

 and subsequent recovery with appreciable nervous 

 troubles resulting. — R. Desplats and R. Paucot : A 

 radloscopic method for the localisation of projectiles. 

 — Louis Ronle : New researches concerning the migra- 

 tion of the salmon. — M. Caullery and F. Mesnil : The 

 structure of a parasitic Copepod, Xenocoeloma brumbti, 

 and Its relations with Its host, Polycirrus arenivorus. 



BOOKS RECEIVED. 



Elementos de FIsIca Descrltlva para a 4* E. 5* 

 Classes. By Profs. F. J. S. Gomes and A. R. 

 Machado. q* Edicao, Revlsta by Prof. A. R. Machado. 

 Pp. 528. (Braga : Livraria Escolar De Cruz and Ca.) 



Rainfall of India. Twenty-fourth Year, 1914. (Cal- 

 cutta : Superintendent Government Printing-, India.) 



Transactions of the Royal Society of Edinburgh. 

 Vol. 1. Part ii. Session 1913-14- Pp- 253-516 + plates. 

 (Edinburgh : R. Grant and Son ; London : Williams 

 and Norgate.) 275. 



The Romanes Lecture, 1915 : Science and the Great 

 War. By Prof. E. B. Poulton. Pp. 47. (Oxford: 

 At the Clarendon Press.) 25. net. 



Live Stock Journal Almanac, 1916. Pp. 188. (Lon- 

 don : Vinton and Co., Ltd.) is. 



City and Guilds of London Institute. Department 

 of Technology, Exhibition Road, S.W. Report on the 

 Work of the Department for the Session 1914-15. Pp. 

 x + 451. (London: John Murray.) 



Fourth Report on the Cost of Food in th§ Produc- 

 tion of Milk in the Counties of Kent and Surrey. By 

 G. H. Garrad. Pp. 95. (Wye: S.E. Agricultural 

 College.) 25. 



New Zealand. Department of Mines. Geological 

 Survey Branch. Bulletin No. 17. (New Series.) 

 The Geology and Mineral Resources of the Buller- 



Mokihinui Subdivision, Westpart Division. By P. G. 

 ton : J. Mackay.) 



Morgan and J. A. Bartrum. Pp. viii + 210. (Welllng- 



Canada. Department of Mines. Geological Survey. 

 Memoir 34 : The Devonian of South-western Ontario. 

 By C. R. Stauffer. Pp. v + 341. (Ottawa: Govern- 

 ment Printing Bureau.) 



Metamorphic Geology. By C. K. Leith and W. J. 

 Mead. Pp. xxIii + 337. (New York: H. Holt and 

 Co.) 2.50 dollars. 



CONTENTS. PAGE 



The "Wheat Problem" and Synthetic Nitrates . 447 



The Fauna and Flora of Central America .... 448 



Fossil Man. By A. S. W 450 



The War and the Future 451 



Our Bookshelf 452 



Letters to the Editor:— 



The Organisation of Science.— " F.R.S." . ... 453 

 Notes on Stellar Classification. {With Diagrams.) 



By Sir Norman Lockyer, K.C.B., F.R.S 454 



A Pliocene Flotsam. {Jllustraled.) . 455 



National Economy in Fuel. By Prof. J. S. S. Brame 457 



Agricultural Education and Research 458 



Sir Henry Roscoe, F.R.S. By Sir T. E. Thorpe, 



C.B., F.R.S 459 



Notes 461 



Our Astronomical Column :— 



o Ceti . . 466 



Comet 191 ■!£ (Taylor) 466 



Geminid Meteor Shower 466 



Notes on Variable Stars 466 



A Tungsten Arc Lamp. {Illustrated.) 467 



The Working and Maintenance of Steam Boilers 468 

 Behaviour of Plants in Response to the Light. 



{Illustrated.) By Dr. «arold Wager, F.R.S. ... 468 



University and Educational Intelligence 472 



Societies and Academies 473 



Books Received 474 



Editorial and Publishing Offices : 



MACMILLAN & CO., Ltd., 



ST. MARTIN'S STREET, LONDON, W.C. 



Advertisements and business letters to be addressed to the 

 Publishers 



Editorial Communications to the Editor. 

 Telegraphic Address : Phusis, London. 

 Telephone Number : <1errard 8830. 



NO. 2408, VOL. 96] 



