36o 



NATURE 



[June 28, 1917 



conjugated biquadratic forms with integral coefficients. 

 — J, S(enaud : Points of identification, in limes of fog, 

 of the great French ports on the Atlantic Ocean. — P. 

 Chevenard : A self-recording differential dilatometer. 

 Two test pieces, one of a standard chrome nickel 

 alloy {^'haros ") of known coefficient of expansion, are 

 arranged to move an optical lever, the magnification 

 being about 300. Curves are given for a ferro-nickel 

 (59-2 per cent, nickel), electrolytic iron, and forged 

 nickel. — J. Repelin and L. Joleaud : Limits of the marine 

 Aquitanian in the Provencal region. — H. Jumelle : The 

 palm-trees producing vegetable horsehair of Mada- 

 gascar. — L. Bordas : The function of some Ichneu- 

 monides as auxiliaries in forestry. Two species of 

 Pimplinae — Rhyssa and Ephialtes — assist in the defence 

 of forests against the attacks of Sirex and Callidium. 

 The Ichneumons deposit their eggs in the larvae of Sirex 

 and other pests, and in consequence are of great ser- 

 vice in the preservation of forest tre^s. — J. Pavillard : 

 Some new or slightly known Protozoa of the Mediter- 

 ranean plankton. 



Cape Town. 

 Royal Society of South Africa, April 18. — Dr. L. 

 P^inguey, president, in the chair. — Sir Thoipas 

 Muir : Note on the expansion of the product of two 

 oblong arrays. The form taken by Binet and Cauchy's 

 well-known expansion of the year 1812 is that of a 

 sum of products of pairs of determinants ; the form 

 of the expansion now given is that of an aggregate 

 of single determinants. The relation between the two 

 is explained and a historical remark added. — J. S. v. d. 

 Lingen : Notes on radiation of crystals, (i) Radiation 

 patterns of the transformation of magnesium hydroxide 

 to magnesium oxide. The patterns show that the 

 reflecting planes of the crystal are disturbed when 

 water is driven off. The " spots " become drawn 

 out into radial lines, and these radial lines reflect 

 the intensity of the X-ray spectrum. (2) Dia- 

 mond tests by radiation patterns. The following 

 stones were examined: — "Made," "spotted" stone, 

 "spotted rejection" stone, and an "inferior brown 

 (block " with a spot in it. The patterns show that a 

 "spot" in a stone causes a discontinuity in the inten- 

 sity of individual spots of the patterns, and that a 

 fracture of the lattice causes a discontinuity of the 

 spots so that they now represent irregular markings on 

 the plate. An ideal diamond's pattern shows a uniform 

 intensity in all the spots. (3) Bultfontein apophyllite, 

 (i) ideal, and (ii) showing a cleavage crack along a 

 cleavage plane. The flaw causes the spots of the 

 "flawed" crystal to present a nebular appearance, 

 whereas the ideal stone shows a uniform distribution 

 of intensity in the elliptic spots. This represents a 

 case of discontinuity in the lattice normal to the inci- 

 dent rays. (4) Serpentine, "malachite, and pseudo- 

 morph quartz. Serpentine shows a regular " radial 

 line " pattern symmetrical to a line parallel to the 

 threads of the crystal. This indicates that serpentine 

 is not triclinic unless every specimen examined was a 

 'T:win." Malachite shows three "lines" parallel to 

 the threads and some minor radial lines normal to the 

 former deviatirie slightlv from the normal. Crocido- 

 lite : A long exposure shows that it Is microcrystalline 

 and that the elementarv units have a tendency to 

 favour a direction parallel to the threads. (5) A 

 square-plate of iodine showed, after an exposure of 

 about an hour, a diffraction phenomenon similar to 

 that described bv Prof. Laub, of Buenos Aires. In 

 this case the nlate shows diagonal lines of zero in- 

 tensity. — S. Schonland : A summary of the distribution 

 of the genera of South African flowerincr plants (with 

 soecial reference to the flora of the Uitenhage and Port 

 Elizabeth divisions). This is to a large extent based 

 on published data, checked and enlarged, however, by 



NO. 24.87. VOL. QqI 



the author's personal knowledge. It was compiled in 

 connection with a study of the flora of Uitenhage and 

 Port Elizabeth, but it is hoped that it may be welcome 

 to other botanists who desire to have readily available 

 a summary showing the general trend of distribution 

 of South African genera.— Prof. G. Elliot Smith : Note 

 upon the endocranial cast obtained from the ancient 

 calvaria found at Boskop, Transvaal (see p. 353). 



BOOKS RECEIVED. 



L'Qiuf et les Facteurs de I'Ontogen^se. By Prof.- 

 A. Brachet. Pp. 349-(-xii. (Paris: O. Doin et Fils.) 

 6 francs. 



The Organisation of Thought : Educational and 

 Scientific. By Prof. A. N. Whitehead. Pp. vii+228. 

 (London : Williams and Norgate.) 6s. net. 



DIARY OF SOCIETIES. 



THURSDAY, Jun-e 28. 



Royal Society, at 4.30. — Contribution to the Study of thje Magnetic Pro- 

 perties of Manganese and of some Special Manganese Steels : Sir Robert 

 Hadfield, Ch. Ch^neveau, and Ch. Geneau.— Note on the Specific Heat of 

 Water : W. R. Bousfield. — The Specific Heat of Aqueous Solutions, with 

 Special Reference to Sodium and Potassium Chlorides : W. R. Bousfield 

 and C Elspeth Bousfield. — The Rankine Trochoidal Wave: Sir Gearge 

 Greenhill. — The Tribo-electric Series : Dr. P. E. Shaw. — And other 

 Papers. 



MONDAY, JuLY_2. 



Aristotelian Society, at 8. — Relation and Coherence : Miss L. S. 

 Stebbing. 



CONTENTS. PAGE 



The Electrification of Our Railways. By Dr. A. 



Russell . 341 



Cotton Cultivation in the United States 342 



General Chemistry. By T. M. L 343 



Our Bookshelf 343 



Letters to the Editor: — 



Chinese and Persian Giraffe Paintings. {Illustrated. ) 



— Dr. C. R. Eastman 344 



The Nature of Renal Activity. — Prof. W. M. 



Bayliss, F.R.S. ; The Reviewer ....... 344 



The Origin of Flint.— Cecil Carus- Wilson ; Dr. 



F. J. Allen 345 



A Note on Chaffinches and Cuckoos. — Honor 



M. M. Perrycoste ... 345 

 Jupiter's Satellites and the Velocity of Light. — Prof. 



A. W. Warrington 345 



Arcs of Halop. — W^alter W. Bryant 345 



Horse-breeding and Horse-racing. By Prof. J. C. 



Ewart, F.R.S 346 



The Destruction of House-sparrows. By Dr. 



Walter E. CoUinge . . ; . 347 



The Publication of the •' Kew Bulletin " 348 



Prof. Kr. Birkeland. By Dr. C. Chree, F.R.S. . . 349 



Notes 349 



Our Astronomical Column :— 



Orbit of Comet 1915a (Mellish) 353 



The Solar Physics Observatory 354 



The Spectra of Nebulae 354 



Annual Congress of the South-eastera Union of 



Scientific Societies . . . 354 



The Future of the X-ray Industry ....... 355 



The Argentine Society of Natural Sciences . . . 355 



Educational Reconstruction 356 



University and Educational Intelligence 357 



Societies and Academies 358 



Books Received 360 



Diary of Societies 360 



ST. 



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