1 88 



NATURE 



[October 30, 1919 



lowest degree. The present paper aims at meeting 

 this objection by employing the method of indeter- 

 minate coefficients, which, although applied to various 

 other problems, has not, it is believed, been previously 

 applied to the particular class of problems in hand. — 

 E. G. Barter : Radiation pressure. This paper is a 

 criticism of Sir Joseph Larmor's method of deducing 

 the pressure of radiant energy, and directs attention 

 to certain obscure points in the train of arguments 

 used by him. 



BOOKS RECEIVED. 



The Genetic and the Operative Evidence Relating 

 to Secondary Sexual Characters. By T. H. Morgan. 

 Pp. 285. (Washington : Carnegie Institution of 

 Washington.) 



Die Leitgedanken. By E. Mach. Zwei Aufsatze. 

 Pp. 31. (Leipzig : J. A. Barth.) 2 marks. 



The Cambridge Pocket Diary, 1919-1920. Pp. xv + 

 267. (Cambridge : At the University Press.) 2s. 6d. 

 net. 



The Thermionic Valve and its Developments in 

 Radiotelegraphy and Telephony. By Prof. J. A. 

 Fleming. Pp. xv + 27g. (London: The Wireless 

 Press, Ltd.) 15s. net. 



The Book of a Naturalist. By W. H. Hudson. 

 Pp. viii+360. (London : Hodder and Stoughton.) 

 12S. net. 



Birds in Town and Village. By W. H. Hudson. 

 Pp. ix+274. (London : J. M. Dent and Sons, Ltd.) 

 10s. 6d. net. 



A Popular Guide to the Wild Flowers of New South 

 Wales. By F. Sulman. Vol. ii. Pp. xxxi + 249+ 

 72 plates. (Sydney : Angus and Robertson, Ltd.) 

 6s. net. 



Australian Wild Flowers. Photographed by .\. E. 

 Sulman. Second series. Pp. ii + 61. (Sydney : .^ngus 

 and Robertson, Ltd.) is. net. 



Some Familiar Wild Flowers. Photographed bv 

 A. E. Sulman. Pp. ii + 66. (Sydney : Angus and 

 Robertson, Ltd.) is. net. 



Das Erleben. By A. Koelsch. Pp. xi-l-389. 

 (Berlin : S. Fischer.) 



Mathematical Papers for Admission into the Royal 

 Military .Academy and the Royal Military College, 

 and Papers in Elementary Engineering for Naval 

 Cadetships, March to July. Edited by R. M. Milne. 

 Pp. ii + 40. (London: Macmillan and Co., Ltd.) 

 js. C)d. net. 



Science and Fruit Growing : Being an Account of 

 the Results Obtained at the Woburn Experimental 

 Fruit Farm since its Formation in 1894. Bv the Duke 

 of Bedford and S. Pickering. Pp. xxii + ^5i. 

 (London : Macmillan and Co., Ltd.) 12.?. 6d. net. 



Revision .'\rithmetic. Logarithms, Slide Rule, 

 Mensuration, Specific Gravity and Density. By T. 

 Thomas. Second edition. Pp. 62. (London : Crosbv 

 Lockwood and Son.) 2S. 6d. 



DIARY OF SOCIETIES. 



MONDAY, NdVKMH'^H > 

 SociETV OF Engineers (at Geological Society), at 5.30.— W. Brown: 



Sewer Ventilation find Health. 

 Apistotelian Society (at 22 Albemarle Street, W.i), at 8. — Prof. J. 



Ward (Pre^ideil's [naiizural Addreii): In tie Rez'nning; . . , 

 SociETV OF Chemical Industry (at Chemical Society), at 8.— Ci A. 



Mitchell : Black Lead Pencils and their Pigments in Writing. — Capt. 



E. T. Sterne : Shawiningan Chemical Industries. 

 Royal Gf,o<;raphical Society (at .^oUan Hall), at 8.30. — Major K. 



Mason : Central Kurdi.stan. 



TUESDAY^ NovKMBF.R 4. 

 RovAL HoRxrcui.TURAi, Society (at London Scottish Drill Hall), at 3.— 



J. Snell : The Ormskirk Potato Trials. 

 Z001.0GICAI Society of Londov, at 5.30. — E. Heron Allen : Exhihition of 



Skia-jraphs of Vermiculina from example': grown in a Hypertonic Tank. 



— Dr. G. Marshall: The, Species of Balaninus occurrinz in Borneo 



(Coleoptera, Curciilionida:). — Miss J. B. Proctor : The Variation in the 



Number of Dorsal Scale-rows in our British Snakes. — G- A. Boulenger. 

 Some New Fishes from near the West Coa«t of Lake Tanganyika — The 

 Hon. Paul Methuen : Description of a New Snake from the Transvaal 

 together with a New Diagnosis and Key of' the Genus Xenocalmus, and 

 of some Batrachia from Madagascar. 



MiNERALOGiCAL SociETV (Anniversary Meeting, at Geological Society), 

 at 5.30. — Dr. W. R. Schoeller and A. R. Powell : ViHamaninite, a New- 

 Mineral. — A. Russell : The Occurrence of Phenasite and Scheelite at 

 Wheal Cock, St. Just, Cornwall. — L. J. Spencer : New Crystal-form* on 

 Pyrites, Calcite, and Epidote. — Ur. G. F. H. Smith : A Curious Crystal 

 Irom the Binnenthal. 



Institution of Civil Engineers, at 5.30. — Sir John Purser Griffith : 

 Presidential Address. 



Rontgen .Society (at the Medical Society of London), at 8. 15. 



Royal Institute of British Architects, at 8.30. — J. W. Simpson: 

 Presidential Address. 



iVEDNESDA.y, November 5. 



Geological Society of London, at 5.30. — H. H. Thomas : Some 

 t- eatures in the Topography and Geological History of Palestine, Illus- 

 trated by Aeroplane Photographs taken during the War, 



IxsTii L'TiON OF AuToiMOBiLE ENGINEERS (at Royal Socictv of Arts\ at 

 8.— br. L. Aitchison : Valve Failures and Valve Steels in Internal Com- 

 bustion Engines. 



Society ok Public Analysts and Other Analytical Chemists (at 

 Chemical Society), at 8. — G. R. Thompson: Egyptian Bricks.- — A. R. 

 Powell and Dr. W. R. Schoeller : The Analysis of Brazilian Zirconium 

 Ore. — Ethel M. Taylor: The Halogen Absorption of Turpentine. 



Entomological Society of London, at %.-~Frobable f aptrst Dr. T. A. 

 Chapman :(i) Contributions to the Life-history oi Lycaenaeup/iemus, Hb.; 

 (2) Notes on Lycacna aicoti, F. — Dr. G. D. H. Carpenter : Notes on 

 Species of Pseudacrsea from Uganda. 



THURSDAY, November 6. 

 Royal Society (jointly with the Koval Astronomical Society), at 4.J0. 



— Sir Frank Dysun, Prof Eddingttn, and Others: Discussion on t;ie 



Results of the Observations obtained at the Total Solar Eclipie on May 19, 



1919. 

 Linnkan Society, at 5. 

 Royal College of Physicians, at 5.— Dr. A. P. Beddard : Some Remar<s 



on Chrcnic Arthritis (Bradshaw Lecture). 

 Chemical Society, at 8. 



FRIDAY, November 7. 

 Royal Astronomical Society (Geophysical Committee), at 5.— Col. 



Sir S. G. Burrard, Prof. A. E. H. Love, and Others : Discussion on 



Isostasy. 

 TechnicAiL Inspection Association (at Royal Society of Arts), at 7.30.— 



Prof. Baly : The Spectroscope in the Science of To-day. 



CONTENTS. PAGE 



Education and Life 169 



Mathematical Text-books . 169 



Mineral Resources of Georgia. By H. L 171 



Our Bookshelf 171 



Letters to the Editor: — 



International Relations in Science. — Sir E. Ray 



Lankester, K.C.B., F.R.S 172 



The Response of Plants to Wireless Stimulation. 



(/IIui«rated.)— Sir J. C. Bose l?^ 

 A New British Enchyirteid Worm.— Rev. Hilderic 



Friend . 174 



A Photoelectric Theory of Colour Vision. — Dr. -H. 



Stanley Allen 174 



Luminous Worms.— H. E. Aldridge 174 



Reconstruction 174 



The Fauna of the Inle Lake 176 



Notes 177 



Our Astronomical Colump : — 



Large Meteors I79 



Comet igig* (Brorsen-Metcalf) 180 



The New Laboratories at Rothamsted. (Illustrated.) 180 

 The British Association at Bournemouth : — 



Section G — Engineering — Opening Address by Prof. 

 J. E. Petavel, D.sic., F.R.S., President of 



the Section . 181 



University and Educational Intelligence 185 



Societies and Academies * 187 



Books Received 188 



Diary of Societies . 188 



Editorial and Publishing Offices : 



MACMILLAN AND CO., Ltd., 



ST. MARTIN'S STREET, LONDON, W.C.2. 



Advertisements and business letters to be addressed to the 

 Publishers. 



NO. 2609, VOL. 104] 



Editorial Communications to the Editor. 

 Telegraphic Address: Phusis, London. 

 Telephone Number : Gerh.\rd 8830. 



