I20 



NATURE 



[April ii, 1918 



with a wider area than Southern India, and the essen- 

 tial problem appeared to be whether his Bundelkhand 

 ifneiss (Laurentian) and the Bengal gneisses (Keewatin) 

 were older than, and unconformable to, the Dhdrwdr 

 system, or whether they were post-Dhdrwdr eruptives 

 corresponding with portions of the Mysore gneissic com- 

 plex. On lithological grounds the Dhdrwdr system 

 is divided into an Upper and a Lower Division. The 

 former is composed largely of basic flows and sills with 

 their schistose representatives. The Lower Division 

 is composed of dark hornblendic epidiorites and schists, 

 which are distinguishable from the greenstones of the 

 Upper Division by their dark colour and practical 

 absence of chlorite. Brief reference was made to the 

 autoclastic conglomerates usually associated with in- 

 trusions of the Champion Gneiss, to the intrusive char- 

 acter of some of the quartzites or quartz-schists, and 

 to the evidence that the limestones are due to meta- 

 somatic replacement of other rocks by carbonates of 

 lime and magnesia. The Dhdrwdr schists of Mysore 

 contain a widely extended series of banded quartz iron- 

 ore rocks, very similar to those of the Lake Superior 

 district. 



BOOKS RECEIVED. 



Our Vegetable Plot. A Year's Record. By S. 

 Graveson. (London : Headley Bros., Ltd.) Price yd. 

 net. 



Radiography and Radio-Therapeutics. By Dr. R. 

 Knox. Part ii., Radio-Therapeutics. Pp. x + 385-606. 

 (London : A. and C. Black, Ltd.) Price 155. net. 



Married Love. By Dr. M. C. Stopes and others. 

 Pp. xvii+ii6. (London: A. C. Fifield.) 5s. net. 



Frontiers. By C. B. Fawcett. Pp. 107. (Oxford: 

 At the Clarendon Press.) 35. net. 



Cellulose. By Cross and Bevan. New impression, 

 with a Supplenfent. Pp. xviii + 348. (London: Long- 

 mans and Co.) 145. net. 



An X-Ray Atlas of the Skull. By A. A. R. Green. 

 Pp. x + 27. (London : Longmans and Co.) los. 6d. 

 net. 



Analytic Geometry and Calculus. By Prof. F. S. 

 Woods and Prof. F. H. Bailey. Pp. xi + 516. (Lon- 

 don : Ginn and Co.) los. 6d. net. 



Equipment for the Farm and the Farmstead. By 

 Prof. H. C. Ramsower. Pp. xii + 523, (London : 

 Ginn and Co.) 105. 6d. net. 



Everyday Physics. By J. C. Packard. Pp. vi+136. 

 (London : Ginn and Co.) 4s. 6d. net. 



Theory of Maxima and Minima. Bv Prof. H. Han- 

 cock. Pp. xiv+193. (London: Ginn and Co.) 

 I05. 6d. net. 



DIARY OF SOCIETIES. 



THURSDAY, April h. 

 RovAL Institution, at 3.— Experimental Psychology: Lt.-Col. C. S. 



Myers. 

 Institution of Electrical Engineers (Cancer Hospital, Fulham Road), 



.-It 6.— Joint Meeting with the Electrical Section of the Royal Society of 



Medicine. — Papers on Medical Electricity. 

 Institution of Mining and Metallurgy, at 5.30. — Presidential Address : 



Hugh F. Marriott. 

 Optical Society (Imperial College of Science and Technology, South 



Kensington), at 8. — The Balsam Problem : J. W. French. 



FRIDAY, April 12. 



5.30. — Absorption and Phosphorescence : Prof. 



MONDAY, April 15. 

 Royal Geouraphical Society, at 5. — Resection in Survey — The First 



Problem : G. T. McCaw. 

 Royal Society of Arts, at 4.30.— Military Explosives of To-day : J. 



Young. 



TUESDAY, April 16. 

 Royal Statistical Society, at 5.15. 

 Illuminating Engineering Society, at 5. — Light and Vision : the 



Physiology of the Retina: Prof. W. M. Bayliss. 

 Institution of Petroleum Technologists, at 8. — Relation between 



Viscosity and the Chemical Constitution of Lubricating Oils : A. E. 



Dunstan and F. B. Thole. 



WEDNESDAY, April 17. 

 Royal Meteorological Society, at 5. — The Variations of Underground 



Water-level near a Tidal River: E. G. Bilham.— Suggestions as to the 



Conditions Precedent to the Occurrence of Summer Thunderstorms, with 



Special Reference to that of June 14, 1914 : J. Fairgrieve. 

 Geoi.ogica l Society, at 5.30. 

 Royal Society of Arts, at 4.30. — Agricultural Machinery : F. S 



Courtney, 



THURSDAY, April 18. 

 Institution of Mining and Mp;iallurgv, at 5.30. 

 LiNNEAN Society, at 5. — Narrative of the Percy "Sladen Expedition 



Brazil in 1913, with Lantern-slides : Prof. J. P. Hill. 

 Royal Institution, at 3. — Present-day Applications of Experimental 



Psychology: Lt.-Col. C. S. Myers. 

 Institution of Electrical Engineers, at 6.— Overseas Distribution o 



Engineering Appliances : L. Andrews. 

 Chemical Society, at 8.— Hugo Miiller Lecture : The Old and the New 



Mineralogy : Sir Henry Miers. 

 Royal Society OF Arts, at 4.30.— Water Power in India: A. Dickinson. 



FRIDAY, April 19. 

 Institution of Mechanical Engineers, at 6. 



Royal Institution, at 5. 30. —The Use of Soap Films in Engineering: Major 

 G. I. Taylor. 



SATURDAY, April 20. 

 Royal Institution, at 3. — Musical Instruments Scientifically Considered 

 Prof. E. H. Barton. 



Royal Institution, 

 E. C. C. Baly. 



Royal Astronomical Society, at =;. — The Secular Acceleration of the Sun 

 as Determined from Hipparchus' Equinox Observations; with a Note on 

 Ptolemy's False Equinox : J. K. Fotheringham. — Differential Transit 

 Observations : W. E. Cooke.— The Chromospheric and Coronal Spectrum 

 (\ 6300-A.76oo)inthe Total Solar Eclipse, 1911, April 28 : Rev. A. L. Cortie. 

 SATURDAY, April 13. 



Royal Institution, at 3.— Musical Instruments Scientifically Considered : 

 Prof. E. H. Barton. 



CONTENTS. PAGE 



A Survey of Experience. By Dr. Bernard Bosanquet loi 



Practical Aspects of Pruning • loi 



Our Bookshelf 102 



Letters to the Editor: — 



The Eotvos "Tour de Force."— Prof. C. V, Boys, 



F.R.S 103 



The Motion of the Perihelion of Mercury.— Harold 



Jeffreys 103 



Bee Disease.— David Ellis ; The Writer of the 



Article • 'Oj 



Prices of Scientific Apparatus.— Fredk. J. Brodie . 104 



Cotton-growing Statistics 104 



Modern Methods of Welding. {Illustrated.) By 



C. R. D 105 



Sulphuric Acid and the War. By Sir T. E. Thorpe, 



C.B., F.R.S 107 



International Scientific Nomenclature 108 



Notes 109 



Our Astronomical Column : — 



Spectrum and Radial Velocity of N.G.C. 1068 ... 1 14 



Changes in the Spectrum of 7 Argus 1 14 



United States Naval Observatory I '4 



Corrections to the Bonn Durchmusterung II4 



Auroral Observations in the Antarctic. {With 



Diaiirams.) By Dr. C. Chree, F. R.S .114 



The Annual Conference of the National Union of 



Teachers . ^'5 



The Indigo Industry no 



A French Society of Chemical Industry 116 



Civil Service Estimates for Science and Education 116 



University and Educational Intelligence 118 



Societies and Academies "9 



Books Received 120 



Diary of Societies 120 



ST. 



Editorial and Publishing Offices: 

 MACMILLAN AND CO., Ltd., 

 M.^RTIN'S STREET, LONDON, W.C.2. 



Advertisements and business letters to be addressed to the 

 Publishers. 



Editorial Communications to the Editor. 

 Telegraphic Address ; Phusis, London. 

 Telephone Number : G'Errard 8830. 



NO. 2528, VOL. icii^ 



