December 8. 1921] 



NATVk'E 



487 



simply AOB, equivalent to (OA, OB^ The com- 

 te angle congruence, expressed as (/j, l.^^{l\, i',), 

 AOB = A'0'B', is shown to be the characteristic 

 gle relation of elementary geometrj- ; its use gives 

 ater simplicit}.- and generality- to geometrical thecwy. 



Books Received. 



Seventh Scientific Report on the Investigations of 

 the Imperial Cancer Research Fund. Pp. viii+gH- 

 22 plates. (London : Taylor and Francis.) 155. 



Report of the Canadian Arctic Expedition, 1913- 

 1918. Vol. 5 : Botany. Part A : Vascular Plants. 

 By J. M. Macoun and T. Holm. Pp. 25+13 plates. 

 (Ottawa : F. A. Acland.), ; 



Berichte des Ohara InstitUts fiir Landwirtschaft- 

 liche Forschungen in Kuraschiki, Provinz Okayama, 

 Japan. By M. Kondo, Xogaku-Kakuschi. Band i. 

 Heft 5. Pp. 5 19-628+ plates 8-1 1. (Kuraschiki : 

 Ohara Schonokai.) 2.80 yen. 



Modern Methods of Welding as Applied to Work- 

 shop Practice. By J. H. Davies. Pp. xviii+263. 

 (London : Constable and Co., Ltd.) 21s. 



Laborator\- Exercises in Applied Chemistry- JFor 

 Students in Technical Schools and Universities. By 

 Dr. W. Moldenhauer. Authorised translation by Dr. 

 L. Bradshaw. -Pp. xii+236. (London: Ctxlstable 

 and Co., Ltd.) 12s. 6d. - " - - 



A History of the Association Psychology. By Prof; 

 H. C. Warren. Pp. x+328. (London*: Constable 

 and Co., Ltd.) i6s. 



Hydraulics of Pipe Lines. By Prof. W. F. 

 Durand. (Glasgow Text-books of Civil Engineering. I 

 Pp. xvi+27i. (London : Constable and Co^, Ltd.) 

 185. 



Fuel and Lubricating Oils for Diesel Engines. 

 By W. Schenker. Pp. xii+114. (London : Constable 

 and Co., Ltd.) 105. 



Principles and Practice of Business. By G. Mairet. 

 (Life and Work Series.) Pp. xii+301. (London : 

 1 Macmillan and Co., Ltd.) 55 ' 



A First Book of Apolied Electricity. BvS. R. 

 Roget. (First Books of Science Series.) Pp. viii+ 

 141. (London : Macmillan and Co., Ltd.) 2s. 6d. 



The Autonomic Nervous System. By Prof.- J. X. 

 Langley. Fart i. Pp. viii+jjo. (Camtwidge : W. 

 Heffer and Sons, Ltd.) 55. net. 



A Concise Guide to the Town and Unisersiti- of 

 Cambridge : In an Introduction and Four Walks. 

 Originally written by Dr. J. W. Clark. Seventh 

 edition, entirely revised. Pp. xx+199+map. (Cam- 

 bridge : Bowes and Bowes.) js. e'd. net. 



Oils, Fats, and Fuels. Bv Thomas Hull. Po." 

 viii+,143. (London: Blackie and Son, Ltd.) 35. 6(f. 

 net. 



Agricultiirar Progress in W'estern India. Bv G. 

 Keatinge. . Pp. xii+253. (London: Longmans, 

 Green -and Co.) 65. net. 



Les Sciences et le Pluralisme. Bv J.-H. Rosny, 

 ain^. (Nouvelle Collection scientifique.) Pp. iv+ 

 210. (Paris : F. Alcan.) 8 francs net. 



Oil Shales. Bv Dr. H. B. Cronshaw. (Imperial 

 Institute Monographs on Mineral Resources, with 

 Special Reference to the British Empire.) Pp. x+80. 

 (London : J. Murrav.) 55. net. 



The Prevention of Malaria in the Federated Mal^v 

 States : A Record of Twent}- Years' Progress. Bv 

 Dr. M. Watson and others. Second edition, revised 

 and enlarged. Pp. xxviii+381. (London : J. Murrav.) 

 2,6s. net. 



NO. 2719. VOL. 108] 



Diary of Societies. 



THURSDAY. Dkoibek 8. 

 ROTAL SociKTr, at 4J0.— Lord Rayleigh : A Study of the Glow 

 of Phosphorus, Periodic Luminosity, and Action of Inhibiting 

 Substances (with experimental Demonstration). — Lord Bay- 

 leigh : The Aurora Line in the Spectrum of the Nieht Sky. — 

 E. F. Armstrong and T. P. Hilditch : A Study of" Catalytic 

 Actions at Solid Surfaces. VII., The Influence of Pressure on 

 the Rate of Hydrogenation of Liquids in Presence of Nickel. — 

 W. D. Womersley : The Energy in Air, Steam, and Carbon 

 Dioxide from lOO^ C. to 2000=" C— Lt.-Col. J. W. Gifford : Atmo- 

 spheric Pressure and Refractire Indices, with a Corresponding 

 Table of Indices of Optical Olass. — H. P. Waran : A New Form 

 of Interferometer. — ^H. Harle : The Viscosities of the Hydrogen 

 Halides. 



RoTAL College or SrBGEOss or ExoLAyo, at 5. — Sir Charles Bal- 

 lance : A Glimpse into the History of the Surgery of the Brain 

 (Thomas Ticary Lecture). 



RoTAL SocftTi or Medicixe (Balneology and Climatologv Section), 

 at 5.30.— Dr. A. G. S. Mahomed : The Relation of Atmospheric 

 Electrical Tariations to the Incidence of Epileptic Fits. — Dis- 

 cussion on the Organisation of the Section. 



Optical Socibtt (at Imperial College of Science and Technology), 

 at 7.30. — L. C. Martin : The Physical Meaning of Spherical Aberra- 

 tion. — Dr. F. Lloyd Hopwood : An Auto-stroboscope and an In- 

 candescent Colour Top. — Lt.-Col. Gifford : Achromatic One Rsdius 

 Doublet Eyepieces. 



Chemical SciciETT (at Institution of Mechanical Engineers), at 8. — 

 Prof. J. W. Gregory : The Genesis of Ores. 



I^TSTiTUTE or Metals (London Section) (at 85 The Minories), at 8. — 

 S. A. E. Wells: Casting in Metal Moulds. 



RoTAL SociETT Or Mkdicxse (Neurology Section) (at Hospital for 

 Paralysis, Maida Yale), at 8. — Clinical Meeting. 



Camera "Clcb, at 8.15. — Capt. H. Lambart : The Intricacies of the 

 Silent Drama and its Making. 



Habveias Societt (at Medical Societv of London), at 3J30. — Sir John 

 Charlton Briscoe, Bart., Sir Sidney Russell Wells, Dr. G. H. 

 Hunt, and Sir William Willeox : Discussion : Is the Anginal 

 Syndrome only of Cardiac Origin? 



SociETi or AxiiQrAKiES, at 8.30. 



FHIDAY, DEcntBEB 9 



DfSTiTrTiox or Water Exgixeers (at Geological Society), at 

 10 a.m.— L. H. Lewis : The Manchester Water Works.— .T." Don : 

 Adsorption in Sand Filters. — C. F. Newton : Indicating and 

 Recording Instruments. — P. B. Crosthwaite : The Louth Flood 

 of 1930. — D. H. Thompson : HTdroloeical Conditions in the (Jhalk 

 at Compton, West Sussex. — Discussion : The Final Report of 

 the Water Power Resources Committee. 



Association or Ecoxomic Biologists (in Botanical Lecture Theatre, 

 Imperial College of Science and Technology), at 2.30. — Prof J. H. 

 Priestley and others : Discussion : The Resistance of the Normal 

 and Injured Plant Surface to the Entry of Pathogenic Organisms. 



Japax Society, at 5.— W. L. Schwartz :' The Potters and Pottery 

 of Satsuma. 



Phtsical Socictt or Loxdox (at Imperial College of Science and 

 Technology), at 5.— G. A. Sutherland and L. Clark: The 

 .\Terage Ranee of fl-ravs in DiflFerent Metals. — Prof. E. Wilson : 

 The Sensitivity of Ballistic GalTanometers. — Prof. R. LI. Jones: 

 The Determination of the Damping Decrement of a Tuning Fork. 

 — Dr. E. A. Owen : The Estimation of the Radium Content of 

 Radio-active Luminous Compounds. 



RoTAL ASTBOXOMICAL SociETr, at 5. — W. M. H. Greaves : Certain 

 Periodic Orbits in the restricted Problem of Three Bodies. — 

 W. M. H. Greaves : Lonff-period Inequalities in the ifovements 

 of Asteroids of which the Mean Motions are nearly half that of 

 Mars. — J. van der Bilt : Observations of Comets made with the 

 10-inch refrjujtor of the University Observatory, Utrecht, Holland. 

 — A. A. Nijland : Observations of Comet 1921a (Reid'i made with 

 the 10-inch refractor of the Universitv Observatorv, Utrecht. Hol- 

 land.— Rev. T. G. B. Phillios : The Third Satellite of Juoiter.— 

 Roval Observatory Greenwich : Mean Areas and Hebographic Lati- 

 tudes of Snnspots in the year 1917. 



RoTAL Socim or Medicixb (Clinical Section), at 5.30. 



IxsTiTCTiox or 51ECHAXICAL ExGiXEEKS (Informal Meeting), at 7. — 

 Continuation of Discussion on Ball and Roller Bearings : Some 

 Recent Types and Criticisms. 



JrxioR IxsTiTFTiox or ExGiXEERS (at Royal United Service Insti- 

 tution), at 7.30. — C. H. Wordingham : "Presidential address. 



RoTAL SocrrvT or "*rin>Tcrvr (Flectro-therapeut'cs Section), at 8.30. — 

 Dr. Carelli : Demonstration of a Method of Radioscopic Ex- 

 amination with the Help of Gas Injections. — Dr. HiddeU : Demon- 

 stration of a Simple -Apparatus for Making Serial Radiographs 

 of Pyloric Region in the Horijontal and Upris-ht Positions. 



Ror»L Socrerr or MEDicnrr (Ophthalmology Section), at S.30. — 

 Clinical Evening. 



SATURDAY, Decevbkb 10. 



IxsTiTTTiox .or Watkb Exgixtebs (at Geological Society), at 

 10 a.m.— L. H. Lewis : The ifanches+er Water Works.— J." Don : 

 Adsorption in Sand Filters. — C. F. Newton : Indicating and Re- 

 cordinp' Instruments.- P. w. Crosthwaite: The Louth Flood of 

 1920. — D. H. Thomnson : Hydrological Conditions in the Chalk 

 »t Comp*on. Wpet Sussex.— Disonssion : The Final Report of the 

 Water Power Resources Committee. 



GiT-innjT Whitf Fellowship (at Lowther Lodge, Kensington Gore. 

 S.W.7). at 2.30. 



VOX DAY. December 12. 



RoT.lL BoiAxic Societt of Loxdox. at 3.— Prof. A. W Bickerton : 

 Gardening (3) : Artistic Gardening. 



