38o 



NATURE 



[July io, 1919 



with a glass envelope containing the f^as the pressure 

 of which is to be measured. The jiipparatus can be 

 utilised as a null instrument by connecting one side 

 to an ordinary mercury manometer, or can be used 

 directly aft<'r calibration. A set of measurements of 

 the pressures of nitrogen peroxide at different tem- 

 peratures is gi\(ii as ;in t\anii)Ie of the application of 

 the manomctci-. A. Joannis : Some properties of the 

 acid phosphates. An account of the action of liquid 

 anhydrous ammonia on the mono- and di-alkali phos- 

 phates. — J. Guyot and L. J. Simon : The action of 

 dimethyl sulphate on the sulphates of the alkalis and 

 alkaline earths. A mixture of methyl sulphate and 

 potassium sulphate in equi-molecular proportions 

 when heated to 200° C\ reacts quantitatively to form 

 potassium pyrosulphate and methyl ether. The action 

 of sodium or lithium sulphate is similar, but the re- 

 action is not complete.— Ch. Audebeau Bey : The 

 lowering of the north of the Egyptian delta since the 

 Roman T^mpire. — S. Stefanescu : " The structure of the 

 plates of the molars of Elephas indicus, and the 

 different origin of the two species of living elephants. 

 A study of the molars leads to the conclusion that the 

 origin of Elephas indicus is quite different from that 

 oi Elephas africanus. — A. Baldit : Certain cases of 

 diminution of the wind veloeity with altitude. — M. 

 Mascre : New remarks on the role of the nourishing 

 laver of pollen. — S. Posternak : Two crvstallised salts 

 of the phospho-organic reserve principle of green 

 plants. The two salts, details of preparation and 

 purification of which are given, have the composi- 

 tions C,H„0„P„Ca,Na« and CeH,,0„PeNa.,.— J. 

 Amar : The hasmatopneic coelKicient. — P. Woog : The 

 variable persistence of luminous impressions on 

 different regions of the retina. — A. Robin : The 

 soluble and insoluble nitrogen in the tissue of can- 

 cerous liver ; new conception of the genesis of 

 cancer. — H. Bierry : Proteid sugar.— H. Coutiere : The 

 limb of the Arthropods. — E. Sollaud : The embrvonic 

 development of the Palaemonidae. — P. C. de Baillon : 

 The existence in locusts and crickets of an organ 

 serving for the rupture of the chorion at the moment 

 of eclosion. — ^M. Baudouin : Mode of ossification of 

 the great trochanter in man of the polished Stone 

 oeriod. 



BOOKS RECEIVED. 



Text-book on Practical Astronomy. By Prof. G. L. 

 Hosmer. .Second edition. Pp. ix+205. (New York : 

 y. Wilev and Sons, Inc. ; I^ondon : Chapman and 

 Hall, Ltd.) 9,s-. 6d. net. 



The Preparation of Substances important in Agri- 

 culture. By Prof. C. A. Peters. Third edition. 

 Pp. vii + Si. (New York: J. Wiley and Sons, Inc.; 

 London : Chapman and Hall, Ltd.) 4.S. net. 



Australia : Problems and Prosoects. Bv the Hon. 

 Sir Charles G. Wade. Pp. 1 1 1'. (Oxford : At the 

 Clarendon Press.) 45. net. 



Vicious Circles in Disease. By Dr. J. B. Hurry. 

 Third and enlarged edition. Pp. xx+377. (London : 

 T. and A. Churchill.) 155. net. 



The Nile Projects. Bv Sir William Willcocks. 

 Pp. xvi-f- 184 + plates 6. (London: E. and F. N. 

 Spon, Ltd.) 



DIARY OF SOCIETIES. 



MONDAY, July 14. 

 Faraday Society, at 8.— L. A. Wild : A Method of Measuring the Mag- 

 netic Hardness of Ferrous Metals and its Utility for carrying out Research 

 Work on Thermal Treatment.— K. Honda and H. Takagi : A Theory of 

 Invar.— W. E. Forsythe : The Disappearing Fihment Type of Optical 

 Pyrometer.— Dr. A. W. Porter : The Equation for the Chemical Equi- 

 hbrium of Homogeneous Mixtures. I. Equilibrium at Constant Tern- | 



perature. — F. H. Jefferey : The Electrolysis of Solutions of .Sodium 

 Nitrate using a Silver Anode.— I. Langmuir : The Mechanism of the 

 Surface Phenomena of Flotation.— E. A. Ashcroft : Some Chemically 

 Reactive Alloys. 



TUESDAY, July 15. 



Society of Chemical Industry (at the Mansion House), at 11 a.m.— 



Annual General Meeting. Address by the President, Prof. Henry Louis. 



—At 3.30 p.m.— Conference. Sir William f. Pope : Inter-Allied Chemical 



Federation.— Prof. C. Moureu : "Sir William Ramsay." 



WEDNESDAY. July 16. 



SficiETY OF Chemical Industry (at the Clothworkers Hall 'Mincing Lane, 

 E.G.), at 10.30 a.m.-i p.m., and 3-5 p m.— Conference on the Production 

 and Consumption of Sugar within the Briii>*h Empire. Speakers : Major 

 Courthope, Sir Richard Garton, Sir Daniel Hall, W. Martineau, Dr. 

 E. J. Russell, Sir George Suiherland, and Louis Souchen. — At the 

 Salters' Hall, St. Swithin's Lane, E.C., at •10.30 a.m.-i p.m., and 

 3-5 p.m.— Conference on Power Plant in Chemical Works. Capt. C. J. 

 Goodwin : Waste Heat Boilers and Pulveri.sed Fuel in Chemical Factories. 

 — A. H. Lymn : Modern Gas Producer Practice for Power Purposes. — 

 J. L. Hodgson : Differential Pressure Meters for Measuring Gas, Sieam, 

 and Air Flow.— Prof. W. A. Bone and P. St. G. Kiike: Recent Develop- 

 ments in Surface Combustion Boilers. — P. Parri.sh : A Modern Chemical 

 Works Power Plant and the Production of Steam from Low Grade Fuel. 

 —Prof. J. W. Hinchley : Notes on the Operation of a Chemical Works 

 Power Plant. — H. Martin : Electrical Supply in a Chemical Works. 

 THURSDAY, July 17. 



Socif.ty of Chemical Industry (at the Salters' Hall, St. Swithin's Lane, 

 E.C.), at 10.30 a.m. -I p.m., and 3-5 p.m.— Conference on Dye Stuffs, 

 Synthetic Drugs, and Associated Products. Dr. Herbert Levinstein: 

 Progress in the British Dyestuff Industry. — James Morton : DyestufTsand 

 British Textiles — Prof. G. T. Morgan: Certain Colour-producing Inter- 

 mediates.— E. V. Evans : The Manufacture of Intermediates.— F. H. 

 Carr : The Manufacture of Synthetic Drugs. — Dr. W. K. Innes : Photo- 

 graphic Chemicals. — Dr. M. O. Forster : The Organised Preparation of 

 Laboratory Chemicals.— At the Goldsmiths' Hall, Foster Lane, EC, at 

 .10.30 a.m.-i p.m. — Conference on the Chrome Tanning Industry. 

 Prof. D. McCandlish: The Development of the Chrome Tanning 

 Industry in the United States of America. — M. C. Lamb : The 

 Progress of the Chrome Tanning Industry in Great Britain. — Dr. 

 Gordon Parker: The War Services of the Chrome Tanning Industry.— 

 At 3-5 p.m — Conference on Recent Developments in the Fermenta- 

 tion Industries. Sir Frederick Nathan : The Manufacture of Acetone. — 

 Amos Gill : The Acetone Fermentation Process and its Technical Appli- 

 cations. — A. Chaston Chapman : The Employment of Micro-organisms in 

 the Service of Chemical Industry — A Plea for a National Institute of 

 ?/Iicro-biology. 



CONTENTS. PAGE 



Productive Duality. By H. W. C 361 



Text-books of Chemical Analysis 362 



The Value of a Garden 362 



Our Bookihelf . . 363 



Letters to the Editor : — 



Military Camouflage. — Major Adrian Klein and 



Dr. J. C. Mottram . . . . 364 

 Question Relatini^ to Prime Numbers. — Prof. G. N. 



Watson, F.R.S ... 364 



Lord Rayleigh, O.M., F.R.S. By J. J. T. ; R. T. G.; 



C H. L. . . ... 365 



Prof Adrian J. Brown, F.R.S. By H. E. A. ... 369 



The Trans-Atlantic Flight of the R 34 369 



Notes . 370 



Our Astronomical Column : — 



The Eclipse and Wireless Telegraphy 374 



The Parallax of the Pleiades 374 



Painting the Corona 374 



The British Scientific Products Exhibition .... 374. 



Strong: Electrolytes and lonisation . ... 376 

 The Fisheries and the Itternational Council. II. 



By Prof. Mcintosh, F.R.S 376- 



University and Educational Intelligence 378 



Societies and Academies • • • • 379 



Books Received 380 



Diary of Societies 380 



ST, 



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 M.VCMILL.^N AND CO., Ltd., 

 MARTIN'S STREET, LONDON, W.C. 



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to be addressed to the 



NO. 2593. VOL. 103] 



Editorial Co)iii>iuiiicalions to the Editor 

 Telegraphic Address: Pnusis, London. 

 Telephone Number: Gerrard 8830. 



