220 



NATURE 



[April 15, 1920 



in Catalysis. ParCXIII. Contact Potentials and Dielectric Capacities 



of Metals, in relation to the Occlusion of Hydrogen, and Hydrogenation. 



— C. S. Garnett : Colouring Matters of Red and Blue Fluorspar. — Miss 



P. V. McKie : Determination of Nitrofonn by Potassium Permanganate. 



— J. I.. Simonsen : (i) The Constituents of Indian Turpentine from Pinus 



loHf^ilolia. Part I. (2) Note on ihe Constituents of Morinda citri/olia. 



(3) Syntheses with the aid of Monochloromethyl lliher. Part IV. The 



Condensation of Ethyl I5enzyl Sodiomalonale and Monochloromethyl 



Ether. 



FRIDAY, .April 16. 

 RoYAi. Society of Medicine (Clinical Section), at 5.30. 

 Concrete Institute, at 6.— E. Kiander Etchells : Submission of Plans 



to Local Authorities. 

 Institution of Electrical Engineers (Students' Meeting) (at Faraday 



House), at 7. — I. Scoit- lageart : The Vacuum Tube as a Transmitter 



and Receiver of Continuous Waves. 

 Institution of Mechanical Encinf,krs (Informal Meeting), at 7. — 



J. E. Baty and Others : Discu-sion on Planing v. Milling. 

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



— F. R. Wade : Labour Unrest — Its Causes and its Cure. 

 Royal Society of Medicine (Electro- Therapeutics Section), at 8.30. — 



Sir Ernest Rutherford : Development of Radiology (Mackenzie Davidson 



Memorial Lecture). 

 Royal Institution of Great Britain, at g. — Prof. H. Maxwell Lefroy: 



The Menace of Man's Dispersal of Insect Pests, 



SATURDAY, April 17. 

 Royal Institution of Great Britain, at 3. — Prof. W. H. Eccles : 

 The Thermionic Vacuum Tube as iJetector, Amplifier, and Generator of 

 Electrical Oscillations. 



MONDAY, April 19. 

 Institution of Electrical Engineers (Informal Meeting) (at Chartered 



Institute of Patent Agenti), at 7. — G. H. Ayres : Group versus Individual 



Driving. 

 Royal Society of Arts, at 8. — Dr. W. Rosenhain: Aluminium and its 



Alloys (Cantor Lecture). 

 Surveyors' Institution, at 8. — C. B. Fisher : Some Problems connected 



wiih Agricultural Policy. 

 RovAL Geographical Society (at ^olian Hall), at 8.30.— Flight-Com- 

 mander G. M. Dyott : An Air-Route Reconnaissance from the Pacific to 



the Amazon. 



TUESDAY, April 20. 

 Royal Institution of Great Britain, at 3. — Major G. W. C. Kaye: 



Recent Advances in X-ray Work. 

 Royal Statistical Society, at 5.15.— Dr. T. H. C. Stevenson : The 



Fertility of various Social Classes in England and Wales from the Middle 



of the Nineteenth Century to 1911. 

 Institution of Civil Engineers, at 5.30. — Sir Dugald Clerk: Fuel 



Conservation in the United Kingdom (James Forrest Lecture). 

 Institution of Pktroleum Technologists (at Koyal Society of Arts), 



at 5 30.— G. F. Robertsliaw : Methods of Examination of Lubricating 



Oils. 

 Royal Photographic Society of Grf.at Britain (Technical Meeting), 



at 7.— Dr.C. E. K. Mees and A. H. Nietz : The Theory of Development. 

 Illuminating Engineering Society (at Royal Society of Arts), at 8. — 



J. Darch and Others : Discussion on the Lighting of Churches. 

 Royal Anthropological Institute, at 8.15. — R. G. Brown: The 



Races of the L hind win, Upper Burma. 

 Royal Society of Medicine (Pathology Section), at 8.30. — Annua 



General Meeting. 



WEDNESDAY, Xpmi. 21. 



Royal United Service Institution, at 3. — Rev. Father B. Vaughan 

 Modern Patriotism. 



Royal Society of Arts, at 4.30.— Air-Commodore E. Maitland : The 

 Commercial Future of Airships. 



Royal -Society of Medicinii (History of Medicine Section), at 5. — 

 Dr. A. Chaplin : The History of Medical Education at the Universities of 

 Oxford and Cambridge. — Mme. Panayotatou : Baths and Bathing in 

 -Ancient Greece. 



Royal Meteorological Socikty, at 5. — Roval Observatory, Green- 

 wich: Polar Night-Sky kecorder Lieut. N. L. Silvester: Local 



Weather Conditions at MuUion, Cornwall. — J. E. Clark : The Surrey 

 Hailstorm of July 16, 1918. 



Geoi ogic.\l Society of London, at 5.30 — J. W. D. Robinson : The 

 Devonian of Ferques (Bas-Boulonnai-s). — li. S. Cobbold : The Cambrian 

 Horizons of Comley (Shropshire) and their Bra' hiopoda, Pteropoda, 

 Gasteropoda, etc. 



Royal Microscopical Society, in conjunction with the Optical 

 Society and the Faraday Society (at the Royal Microscopical Society), 

 7 to 10. — General Discussion on The Mechanical Design and Optics of 

 the Microscope. — Prof. J. Eyre: Opening Remarks. — J. E. Barnard: 

 A Genera! Survey. —A. The M echanical Design of the Microscofie. 

 (a) General. Prof. F. J.Cheshire: The Mechanical Design of Micro- 

 scopes. — C. Beck: The Standard Microscope. — F. W.Watson Baker: 

 Progress in Microscopy from a Manufacturer's Point of View. — P. Swift : 

 A New Microscope. — \b) Metallurgical. Dr. W. Rosenhain: The Metal- 

 lurgical Microscope. — Prof C. H. Desch : The Construction and Pesign 

 of Metallurgical Microscopes.— E. F. Law : The Microscope in Metal- 

 lurgical Research. — H. M. Sayers: Illumination in Micro-metallography. 

 — (c Petrological. Dr. J. W. Evans : The Requirements of a Petrological 

 Microscope. — B. The Optics of the Microsccfie. Prof .\. E. Conrady : 

 Microscopical Optics.— Dr. H. Hartridge : An Accurate Method of 

 Objective Testing. — H. S. Rvland : The Manufacture and Testing of 

 Microscope Objectives. — F. Twyman : Interterometric Methods. 



THURSDAY, April 22. 



Royal Institution of Great Britain, at 3. — S. Skinner: The Tensile 

 Strength of Liquids. 



Royal Society, at ^.jo.— Probable Pa/iet s.—Frof. W. E. Dalby : Re- 

 searches on the Elastic Properties and the Plastic Extension of Metals.-r- 



NO. 2633, VOL. 105] 



H. W. Hilliar : Experiments on the Pressure Wave thrown out by 

 Submarine Explosions. — E. F. Armstrong and T. P. Hilditch : A Study 

 of the Catalytic Action at Solid Surfaces. III. The Hydrogenation of 

 Acetaldehvde and the Dehydrogenation of Ethyl Alcohol in the Presence 

 of Finely Divided Metals. IV. The Interaction of Carbon Monoxide 

 and -Steam as conditioned by Iron Oxide and by Copper. — Dr. T. R. 

 Merton : The Structure of the Baliner Series of Hydrogen Lines. — Prof. 

 H. A. Wilson: Diamagnetism due 10 Free Electrons. 



FRIDAY, April 23. 



Physical Society, at 5.- M. C. E. Guillaume : The Anomaly of the 

 Nickel-Iron Alloys : Its Causes and its Applications (Guthrie Lecture). 



Institution of Mechanical Fk&inkers, at 6.— The late W. J. Lineham : 

 (i) The Hardening of Screw-Gauges with the least Oislorlion in Pitch 

 (referring to Water Hardening). (2) The Hardening of Screw-Gauges 

 with the least Distortion in Pitch (referring to Oil Hardening). 



Royal Institution of Great Rritain, at 9. — Sir Israel Gollancz: 

 Shakespeare's Shvlock and Scott's Isaac of York.' 



SATURDAY, April 24. 

 Royal Institution of Great Britain, at 3. — Prof. W. H. Eccles: The 

 Thermionic Vacuum Tube as Detector, Amplifier, and Generator of 

 Electrical Oscillations. 



CONTENTS. PAGE 



The Encouragement of Discovery 189 



English Cytology. By J. B. G 190 



Matrices. By G. B. M. .191 



The Chemistry of Animal Products. By W. M. B. 192 



Physics : Theoretical and Practical. By H. S. A. 193 



Minerals and Metals 193 



Our Bookshelf ... 195 



Letters to the Editor: — 



ThePlumageBillandBird Protection. — Dr. Walter E. 



Collinge ... 196 



The Physiology of Migrations in the Sea. — Prof. 



Alexander Meek 197 



Muscular Efficiency. ( Wiik Diagrams.) — Pl. Mallock, 



F.R.S 197 



A Dynamical Specification of the Motion of Mercury. 



— aeorge Vv^. Walker, F.R.S 198 



The Construction of a Magnetic Shell Equivalent to a 



Given Electric Current. — Dr. A. A. Robb . . . 199 

 Volcanic Rocks in the Anglo-Egyptian Sudan. — Dr. 



G. W. Grabham 199 



The FitzGerald-Lorentz Contraction Theory. — 



Horace H. Poole 200 



Moseley Memorial. — Sir Henry A. Miers, F.R.S., 



C. G. Darwin, and Dr. H. Robinson . . . 200 



The Aurora of March 22-23.— W. B. Housman . . 200 



The Nitrogen Problem : By-products .... 201 



A Survey of National Physique. {Wilh Diagram.) 202 



The Doctor of Philosophy in England 204 



British Crop Production. {Coiitittueu.) By Dr. 



Edward J. Russell, F.R.S 206 



Obituary 208 



Notes . . 209 



Our Astronomical Column : — 



Conjunction of Jupiter and Neptune 213 



A Nova in a Spiral Nebula . 213 



The Madrid Observatory 213 



National Education 213 



Aeronautics at the Imperial College 214 



The Parallaxes of Globular Clusters and Spiral 



Nebulae 215 



The Forestry Commission 215 



Recent Fishery Investigations. By J. J 216 



Flora of the Hawaian Islands 217 



University and Educational Intelligence 217 



Societies and Academies 217 



Books Received 219 



Diary of Societies . . .%.... 219 



(Index) 



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