340 



NATURE 



[June 26, 19 19 



paraffins, ranging from pentane to octane, with a 

 critical solution temperature of about 72° C ; and 

 saturated cyclic hydrocarbons with a critical solution 

 temperature of about 36° C. — M. de Mallmann : The 

 system chlorine-hypochlorous acid-sodium hypo- 

 chlorite.— M. Dalloni : The dome of Noisy-les-Bains 

 and the Habra (Algeria). — M. Mascr^ : The rdle of 

 the nutritive layer of pollen. — H. Piiron : The part 

 played by physiological energy losses in the relation 

 which unites the time of sensorial latency to the in- 

 tensity of stimulation. — J. E. Abelous and J. Aloy : 

 The inversion of saccharose by mechanical ionisation 

 of water. A 5 per cent, solution of sugar in water, 

 after five passages through a spray pulveriser, con- 

 tained the same amount of invert-sugar as a similar 

 solution to which four drops of pure hydrochloric acid 

 has been added and left in repose for the same time 

 (40 minutes). — A. Vandel : The determinism of the 

 two modes of reproduction of Polycelis cornuta. — 

 MM. Hartmann and Peyron : Neo- formations of chorio- 

 ectodermic origin in tumours of the testicle. 



June 10. — M. L^on Guignard in the chair. — G. 

 Bigourdan : Co-ordinates and instruments of the 

 observatory for navigation. Historical account of the 

 position and instruments in the observatory in the 

 H6tel de Cluny, dating from about 1750-75. — A. 

 Hateau : Theory of the flight of aeroplanes at various 

 altitudes. — E. Borel : The theory of ensembles and the 

 decimal numbers.^?. Boutroux : A mode of definition 

 of a class of multiform functions in the whole of the 

 domainof existence of these functions. — H. Cramer : The 

 distribution of the prime numbers. — F. Michaud : The 

 vapour-pressure of liquids in thin layers. Starting 

 with data by Devaux on the variation of the surface 

 tension of a thin film of one liquid on another, such 

 as oil on water, it is shown that the vapour-pressure 

 of the oil on the water under these conditions is 

 reduced to about i /5000th of the normal saturation- 

 pressure. Similar considerations apply to the case of 

 a thin film of a liquid, on a solid, such as water on 

 glass. — Ph. Glangeaud : The casual or superposition 

 volcanic group of the Mont Dor6 massifs. — C. E. 

 Brazier : The influence of the vertical distribution of 

 temperatures on velocities of the wind measured in the 

 neighbourhood of the soil.^G. Bertrand : The pre- 

 servation of fruit without the addition of sugar, 

 alcohol, or antiseptics, and without sterilisation bv 

 heat. Fruit washed in cold water can be kept in a 

 good state of preservation in cold water, provided 

 that the bottles are comoletelv filled and that air is 

 whollv excluded. — R. Fosse : The mechanism of the 

 artificial formation of urea by oxidation and the 

 synthesis of natural principles in plants. 



BOOKS RECEIVED. 



The Analytical Geometry of the Straight Line and 

 the Circle. By J. Milne. Pp. xii + 243. (London : 

 G. Bell and Sons, Ltd.) 55. 



Projective Vector Algebra : An Algebra of Vectors 

 Independent of the Axioms of Congruence and of 

 Parallels. By Dr. L. Silberstein. Pp. vii + 78. 

 (London : G. Bell and Sons, Ltd.) 75. 6d. net. 



Physical Laboratory Experiments for Engineering 

 Students. By Profs. S. Sheldon and E. Hausmann. 

 Part i. : Mechanics, Sound, Heat, and Light. Pp. v+ 

 134. (London: Constable and Co., Ltd.) 65. net. 



Photography : Its Principles and Applications. Bv 

 A. Watkins. Second edition. Pp.xvi + 333. (London: 

 Constable and Co., Ltd.) los. 6d. net.' 



Farm Concrete. Bv K. J. T. Ekblaw. Pp. xi-l-295. 

 (New York : The Macmillan Co. ; London : Mac- 

 millan and Co., Ltd.) 85. 6d. net. 



The Modern Milk Problem in Sanitation, Economics, 

 NO. 2591, VOL. 103] 



and Agriculture. By J. S. MacNutt. Pp. xi + 258-1- 

 plates xvi. (New York : The Macmillan Co. ; London s 

 Macmillan and Co., Ltd.) 105. 6d. net. 



Peach-Growing. By H. P. Gould. Pp. xxi+426+- 

 plates xxxii. (New York : The Macmillan Co. ; 

 London: Macmillan and Co., Ltd.) los. 6d. net. 



Navigation By Prof. H. Jacoby. Second edition. 

 Pp. xi + 350. (New York: The" Macmillan Co.; 

 London : Macmillan and Co., Ltd.) iis. 6d. net. 



The Causes and Course of Organic Evolution. By 

 Prof. J. M. Macfarlane. Pp. ix-f875. (New York: 

 The Macmillan Co ; London: Macmillan and Co., 

 Ltd.) 175. net. 



DIARY OF SOCIETIES. 



THURSDA y, June 26. 



Royal Society, at 4.30.— Dr. A. E. H. Tutton : Monoclinic Double 

 Selenates of the Cobalt Group.— Hertha Ayrton : A New Method 

 of Driving off Poisonous Gases.— Dr. F. W. Aston : Experiments 

 with Perforated Electrodes on the Nature of the Discharge in Gases at 

 Low Pressure. — Mary Seegar and Prof. Karl Pearson : De Saint-Venant 

 Solution for the Flexure of Cantilevers of Cross-section in the Form of 

 Complete and Curtats Circular Sectors; and on the Influence of the 

 Manner of Fixing the Built-in End of the Cantilever on its Deflection.— 

 Dr. H. Jeffreys : The Relation between Wind and the Distribution of 

 Pressure.— Prof. C. H. O'Donoghue : The Blood Vascular System of the 

 Tuatara, Sphenodon punctatus.—And other Papers. 

 FRfDAY, June 27. 



Physical Society, at >;.— Prof. C. L. Fortescue : The Current-Voltage 

 Characteristics of High-Votage Thermionic Rectifiers.— Prof. Ernest 

 Wilson : The Measurement of Small Susceptibilities by a Portable 

 Instrument. 



MONDAY, June 30. 



Institution of Electrical Engineers, at 6.— Capt. L. B. Turner: The 

 Oscillatory Valve Relay : A Thermionic Trigger Device. 



CONTENTS. PAGE 



Forest Policy and Law in the United States 321 

 Inorganic and Physical Chemistry. By Prof. W. C. 



McC. Lewis .322 



The Primitive Nervous System. By Prof. G. 



Elliot Smith, F.R.S 322 



Our Bookshelf . 323 



Letters to the Editor :— 



The Credibility of Long-continued Experiments. — 



Dr. E. J. Russell, F.R.S. 324 



The Lustre of Some Feathers of Humming Birds. — 



H. J. Charbonnier .... 324 



The Stinging Instinct in Bees and Wasps. — F. W. L. 



Sladen ... 325 



The American Astronomical Society.-— Dr. Joel 



Stebbins . -325 



Grain Pests and their Investigation. By Dr. A. D. 



Imms • • 325 



The Jewelry Trade in War-Time 326 



Notes . . . 327 



Our Astronomical Column : — 



The Planets 35« 



Admiralty Tide-tables 33' 



The National Physical Laboratory 331 



Physiology of Sex and Reproduction in Poultry. 



By J. A. T 332 



Science and Industrial Development 333 



The History of the London Plane. {Illustrated.) . 333 



University and Educational Intelligence 336 



Societies and Academies 337 



Books Received 34° 



Diary of Societies 340 



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Advertisements and business letters to be addressed to tht 

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Editorial Communications to the Editor. 

 Telegraphic Address : Pnusis, London. 

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