576 



NATURE 



[June 30, 192 1 



Things Series.) (London and New York : A. Melrose, 

 Ltd.) 6^. net. 



Human Embryology and Morphology. By Sir A. 

 Keith. Fourth edition, revised and enlarged. Pp. 

 viii + 491. (London : E. Arnold.) 30s. net. 



The National Physical Laboratory : Report for the 

 Year 1920. Pp. 132. (London : H.M. Stationery 

 Office.) 5^. net. 



Espace, Temps et Gravitation : La Th^orie de la 

 Relativity g^neralis^e dans ses Grandes Lignes. By 

 Prof. A. S. Eddington. Ouvrage traduit de I'Anglais 

 by J. Rossignol. Pp. xii+262 + iv+i49. (Paris: J. 

 Hermann.) 28 francs. 



Liverpool Marine Biology Committee. Memoirs on 

 Typical British Marine Plants and Animals. No. 

 xxiv. : Aplysia. By Nellie B. Eales. Pp. viii+84+ 

 7 plates. (Liverpool : University Press.) 4s. 6d. 

 ■ Memoirs of the Geological Survev. Special Reports 

 on .the Mineral Resources of Great Britain. Vol. 

 xviii. : Rock-Salt and Brine. By Dr. R. L. Sherlock. 

 Pp. vi+ 123 + 2 plates. (London": E. Stanford, Ltd.; 

 Southampton : Ordnance Survey Office.) 5s. net. 



Some Wemba Words : Some Meanings and Ex- 

 planations. By E. B. H. Goodall. Pp. 140. (Lon- 

 don : Oxford University Press.) 7s. 6d. net. 



The Treaty Settlement of Europe : Some Geographic 

 and Ethnographic Aspects. Bv Prof. H. J. Fleure. 

 <The World of To-Day.) Pp. '83. (London : Oxford 

 University Press.) 2s. 6d. 



Diary of Societies. 



THURSDAY, Junk 30. 



Institution or Civil K.noineebs (Engineering Conference), at 

 10 a.m. — VV. \V. tirierson : The Use of Heintorced Concrete on 

 Uailways. — H. J. Fereday : Impact Tests and Allowances. — A. H. 

 Hall : The Influence of the Automatic and Semi-automatic 

 Machine on the Skill and Hesourcefulness of the Mechanic and 

 Operator. — A. Musker : Mechanical Appliances and Labour in 

 i^ouding and Unloading Ship's Cargoes. — Prof. VV. E. Ualby : 

 The Elastic Limit. — Prof. E. Q. Coker : The Effect of Scratches 

 in Materials. — C. P. Sandberg : Damage to Tires and Kails 

 caused by Brakes or Slipping \s heels.— G. Hatton : The Existing 

 Practice of Inspecting Work and Materials. — M. E. Denny: The 

 Design of Fabricated Ships from the Labour-saving Point of 

 View. — J. C. Telford : Economy of Labour on Shipbuilding as 

 effected by Fabricated Ships, etc. — E. R. Mumford : Recent Tank 

 Research in Screw Propellers. — E. H. Richards and M. G. 

 Weekes : Straw Filters for Sewage-purification. — J. Haworth : 

 Activated Sludge. — J. D. Watson: De-watering Sludge. — J. 

 Daliiel : Battery Locomotives. 



Institution of MECHANic.tL E.vGiNKF.ns, at 10.1.=; a.m.— Conference on 

 the Means of Improving the Thermal Effioicncy of Heat Power 

 Plants. — H. E. Wimperis : Internal-combustion Engine Theory, 

 with relation to Higher Economy.— F. Samuelson : High Steam- 

 Pressxire and other Means of increasing Economy of Steam-Engincs. 

 — E. V. Evans : Chemistry of Combustion. — A. Hutchinson and 

 F. Bainbridge : Blast-Furnace Gases. — D. Wilson : Boiler-House 

 Management (General Causes of Boiler Inefficiency). — Prof. W. A. 

 Bone : Low Temperature Carbonisation. — H. Dunell : Engine- 

 House Management (General Causes of Steam-Engine Inefficiency). 

 — A. E. L. Chorlton : Super-Compression. 



Royal Society, at 4.30.— Sir J. J. Dobbie and Dr. J. J. Fox : 

 The Absorption of Light bv Elements in a State of Vapour. 

 The Halogens.— Prof. W. "A. Bone and the late W. A. 

 Haward : Gaseous Combustion at High Pressures. Part II. The 

 Explosion of Hydrogen-Air and Carbon-monoxide-Air Mixtures. — 

 Prof. A. E. H. Love and F. B. Pidduok : Lagrange's Ballistic 

 Problem.— J. Proudman : The Principles of Internal Ballistics. — 

 R. H. Fowler : A Simple Extension of Fourier's Integral Theorem 

 and Some Physical Applications in particular to the Theory of 

 Quanta.— Capt. D. Brunt : The Dynamics of Revolving Fluid on 

 a Rotating Earth ; and other papers.— The following papers will 

 be read in title :— Takeo Shimizu : A Preliminary Note on 

 Branched a-ray Tracks.— Takeo Shimizu : A Reciprocating Ex- 

 pansion Apparatus for detecting Ionising Rays. — Prof. R. W. 

 Wood : The Time Interval between Absorption and Emission of 

 Light in Fluorescence. 



FRIDAY, JULT 1. 

 Institution of Civil Engineers (Engineering Conference), at 

 10 a.m. — R. G. H. Clements : Road Vehicles and their Relation 

 to Road Surfaces. — A. Dryland :^ Advantages of Bituminous 

 Macadam. — C. H. J. Clayttm : The Conservancy and Maintenance 

 of Rivers from the Point of View of Land Drainage. — R. F. 

 Grantham : The Effect of Sluices and Barrages on the Discharge 

 of Tidal Rivers.— G. E. W. Cruttwell : The Utility of Models for 

 Estuarial Experiments. — H. C. Reid : The Relative Advantages 

 of Dredging and Training-walls in Estuaries. — E. Latham : The 



NO. 2696, VOL. 107] 



Use of Inertia Gauges in Pile Driving. — A. L. Bell : The Bearing 

 Power of Soils. — Sir James McKechnie : Internal-combustion 

 Engines with Large Cylinders.— Sir Vincent L. Raven : The 

 Mechanical Advantages of Electric Locomotives compared with 

 Steam. — T. Crook : The Effect of the Wfir on Mineral Supplies.— 

 M. ueacon : The Utilisation of Exhaust Steam in Turbines.— 

 W. c. Mountain : Steam vermg Electric Winding.— S. Cowper- 

 Coles : The Relative Values of Protective Metallic Coatings for 

 Iron and Steel. — J. Richardson : Recent Progress in Large 

 Diesel Engines for the Mercantile Marine. — R. J. Walker and 

 8. S. Cook : Experience with Marine Turbine Reduction-gears. — 

 E. Sandeman : Compensation Water. — F. W. Macaulay : Pipes for 

 Pressure Conduits.— Dr. H. Lapworth : The Relation of Run-off 

 to Rainfall. — Economic Limits of Dijtribution from Coal-fired 

 Stations. — B. Welbourn : Low-voltage Overhead Distribution. 



Institution of Mechanical Engineers, a ; 10.30 a.m.— Conference on 

 the Aleans of Improving the Thermal Efficiency of Heat IPower 

 Plants. — R. Nelson : Waste-Heat Utilisation. — Sir Henry Fowler : 

 Superheating.— Dr. W. R. Ormandy : Liquid, Colloidal, and 

 Powdered Fuels. — H. Moore : Liquid Fuels (Internal-combustion 

 Engines).— A. W. Bennis : Automatic Stokers.- W. H. Patchell : 

 Air Heating for Boiler Furnaces. — C. E. Stromeyer : Feed-Heat- 

 ing and Economisers.— Prof. AV. E. Dalby : The Indicator as 

 an Aid to Economy. 



Geologists' Association (in .^^rchitectural Theatre, University 

 College), at 7.30.— H. Bury: Some High-level Gravels of North- 

 East Hampshire. 



MONDAY. July 4. 



RoTAL Botanic Society of London, at 3.— Prof. A. R. Bickerton : 

 The Generic Simplicity and Great Importance of Basic Prin- 

 ciples in all Scientific Work. (1) The General Graphics of 

 Science. 



RoTAL Institution of Great Britain, at 5.— General Meeting. 



Aristotelian Society (at University of London Club, 21 Gower 

 Street), at 8.— Dr. F. C. S. Schiller : Arguing in a Circle. 

 WEDNESDAY, July t5. 



RoTAL Society of 5Iebicine (Annual General Meeting), at 5.— Pre- 

 sentation of Gold Medal to Sir Almroth Wright. 



THURSDAY July 7. 

 Medico-Leoal Society (Annual General Meeting) (at 11 Chandos 

 Street, W.l), at 8..30.— Prof. A. Louise Mcllroy : Som* Factors 

 in the Control of the Birth-rate. 



CONTENTS. PAGE 



American and British Superannuation Systems 545 



Lord Rayleigh's Scientific Papers 546 



Studies of British Mammals 547 



Forestry in France 548 



Our Bookshelf 549 



Letters to the Editor:— 



Co-operative Indexing of Periodical Literature. — 

 Dr. F. A. Bather, F.R.S. ; Prof W. M. 

 Flinders Petrie, F.R.S. ; Dr. John W. Evans, 

 F.R.S. ; Arthur Percival Newton; Stephen 



Gaselee, C.B E 550 



W. Warde Fowler : A Personal Appreciation. — 



H. E. A. . . . 551 



lonisation Potential and the Size of the Atom. — Prof. 



' A. S. Eve ..... 552 



A Novel Magneto-Optical Effect. — Sir Oliver 



Lodge, F.R.S. . . 553 



Helicopters.— A. Mallock, F.R.S. . . . -553 



A Physical Interpretation of the Energy Quantum. — 



Ian Auckeri 553 



University Stat sties of the United Kingdom, 



1919-^0 554 



Protective Measures against X-rays and Radium 557 

 Cosmogony and Stellar Evolution. I. [Illustrated.) 



By J. H. Jeans, Sec.R.S 557 



Obituary : — 



Dr. A. M. Kellas 560 



Notes .... 561 



Our Astronomical Column : — 



Occultation of Venus . . 566 



The Total Amount of Starlight ......... 566 



Periodicity of Variable Stars 566 



Royal Sanitary Institute: Folkestone Congress, 



June 20-25 567 



The Importance rf Pesearch in the Development 

 of the Mineral Industr.es. By Sir Richard 



Redmayne, K C.B. . 568 



The Genetics of Sex. By Prof. R. Ruggles Gates 571 

 University and Educational Intelligence . . . 572 



Calendar of Scientific Pioneers 573 



Societies and Academies ... 573 



Books Received 575 



Diary of Societies 576 



