3-! 4 



NA TURE 



[AucusT I, 1907 



June 27. — " On a Standard of Mutual Inductance." By 

 Albert Campbell. Comnumicated bv Dr. R. T. Glaze- 

 brook, K.R..S. 



The author has designed a standard of mutual induct- 

 ance of such a nature that its value is accurately calculable 

 from the dimensions, and large enough to give good 

 sensitivity in actual use. A high enough value (say 001 

 henry) can be got by having one of the associated circuits 

 a coil of many layers. The objections to such a coil arc 

 overcome as follows : — 



The primary circuit is a pair of single-layer coils wound 

 on a single marble cylinder ; their dimensions can be 

 accurately determined. The secondary is a coil of many 

 layers co-axial with, and midway between, the two primary 

 coils, and of such radius that the mutual inductance is a 

 maximum for change of radius. \ series of curves is 

 given from which the proper dimensions were chosen. All 

 round the mean circumference of the secondary coil the 

 magnetic field due to the current in the primary coils is 

 zero, and is very nearly so over the section of the wind- 

 ing, thus allowing accurate calculation. The principle is 

 applicable to other probleins involving mutual inductance. 



Paris. 

 Academy of Sciences, Julv 22. — M. A. Ch-^uvepu in the 

 chair. — .\ phenomenon resembling the spheroidal state : 

 G. Lippmann. \ strip of plaster of Paris adhering to 

 a plane surface of glass becomes detached on raising the 

 temperature above 100°, sliding over the surface with 

 the greatest ease. — The effect of oxygen, osmotic pressure, 

 acids, and alkalis in experiments on parthenogenesis : 

 Yves Delage. The presence of oxygen is not necessary 

 for the determining of parthenogenesis in starfish — it is 

 even harmful ; the presence of divalent ions is not at 

 all essential, a solution of sodium chloride being often 

 sufficient among sea-urchins. The requisite condition of 

 parthenogenesis among certain of the latter consists in 

 the treatment of the eggs by an acid solution, afterwards 

 an alkaline, the first coagulating, the second liquefying 

 certain constituents of the egg protoplasm. — The dielectric 

 cohesion of helium : E. Bouty. By repeated purifications, 

 the value of the dielectric constant was found to be re- 

 duced from 6i-8 to 18-3. — The effect indicated by the 

 electrolytic detector : M. Tissot. — A new optical pro- 

 perty of magnetic bi-rcfraction belonging to certain non- 

 colloidal organic liquids : A. Colton and H. Mouton. 

 Nitrobenzene shows a magnetic bi-rcfraction of positive 

 sign, increasing proportionally to the square of the field 

 and the thickness traversed. This property is more or 

 less marked throughout the aromatic series, but not among 

 aliphatic compounds. — The spectrophotography of minerals 

 in different regions of the spectrum ; galena and 

 argyrite : A. de Gramont. — The coagulation of albumins 

 by the actions of ultra-violet light and radium : Georges 

 Dreyer and Olav Hanssen. Both serous and egg 

 albumin are coagulated under the action of a prolonged 

 intense light. The serum of the horse is only slightly 

 coagulated by light ; a solution of peptone remains clear, 

 though becoming yellow, the same effect being also 

 noticeable with casein. These results are all due to the 

 ultra-violet portion of the light. Radium coagulates 

 vitellin, but apparently no others. — The heats of form- 

 ation of alkaline protoxides : E. Reng^ade. — A mixed 

 anhydride of sulphuric and nitric acids : Am^ Pictet and 

 Georges Karl. Nitric anhydride dissolves with evolution 

 of heat in freshlv distilled liquid sulphuric anhydride. 

 The product distils entirely at 2iS°-22o°. and analysis 

 shows it to have the composition (SO,)|N,0.. — The 

 combination of nickel and cobalt with boron : Binet 

 du Jassonneix. Compounds have been obtained of the 

 composition NiBo and CoBo (already described by M. 

 Moissan), Ni.Bo, Co, Bo, NiBo., and CoBo,. — \ new 

 silicide of platinum : P. Lebeau and .\. Novitzky. This 

 compound, of the formula SiPt, can be obtained by direct 

 union, is crystallisable, and chemically resembles platinum. 

 — K general method of preparation of anhvdrous metallic 

 bromide;, with oxides as a starting point : F. Bourion. 

 The simultaneous use of sulphur chloride and hydrogen 

 bromide gas provides a convenient means to this end. 



— The alloys of nickel and tin: Em. Vigouroux The 



effect rf rleclrir sp.urking upon a mixture of nitrogen 



and oxygen at low temperatures : E. Briner and E. 

 Durand. — Discontinuities observed in the molecular con- 

 ductivity of dissolved chromium sulphates : Albert Colson. 

 — The rotatory power of the proteids extracted from the 

 flour of cereals by aqueous alcohol : M. Lindet and I,. 

 Ammann. — Menthane i ; S-dicarboxylic acid and a new 

 dicyclic ketone : Ph. Barbier and V. Grigrnard. — The 

 origin of the deposits of colouring matter in red wine : 

 V. Martinand." Malic acid in wine must, and its de- 

 struction in fermentation : W. Mestrezat. — The lique- 

 faction by diastase of fecula starch : A. Fernbach and 

 J. Wolff. — Living reagents and diffusion : Michel 

 Vegounow. — A new genus of Sapotacea; in West Africa, 

 with seeds containing an edible fatty matter : .Aug. 

 Chevalier. This tree provides a fine red well-veined 

 wood, of density almost equal to unity. — The Pachy- 

 podium of Madagascar : MM. Costantin and Bois. — 

 New researches on the cytology of the ' seeds of 

 Graminaceie : A. Guilliermond. — The morphological 

 value of the caruncle of Notopygos labialus : A. Malaquin 

 and A. Dehorne. — The destructive function of the spleen 

 towards trypanosomcs : A. Rodet and G. Vallet. In the 

 case of infection by Trypanosoma hrucci, the spleen 

 actively destroys the parasites. — The injection of artificial 

 serums : C. Fleig. Those containing iron have been used 

 with success in many cases of chlorosis. — The activity o^H! 

 Etna : A. Ricco. ^H 



C.-VLCUTTA. " ^1' 



Asiatic Society of Bengal, lulv 3. — Nriics on the Pollin- 

 ation of flowers in India. Note No. 4. On cotton in 

 Behar : 1. H. Burkill. The flowers of Gossypium 

 neglcctiini and G. intcrmeditim in Behar arc a little visited 

 by insects, chiefly small Hymenoptera of the genera 

 Ceratina and Halictus, w-hich seek honey in vain, and may 

 collect pollen. Longer longued insects, such as Xylocopa, 

 ;\nthophora, and a few Lepidoptera only rarely go to the 

 flowers. Plants intermediate between the two species, 

 which are grown mixed, testify to the occurrence of cross- 

 fertilisation : but they are rare, and the very early self- 

 pollination in the flowers shows how much more the 

 cotton crop depends on spontaneous self-fertilisation than 

 on pollination by insects or other external agency. 



CONTENTS. PAGE 



Zoology as an Experimental Science. By J. A. T. 313 



Books on Patent Law 314 



Our Book Shelf: — 



• Gulicli : "The Efficient Life" 315 



Johns: " Flowers of the Field " 315 



" Cyclopedia of American Agriculture " 315 



Letters to the Editor" — 



Root Action and Bacteria.— Spencer Pickering, 



F.R.S 315 



Biological Expedition to the Eirket el Qurun. — 



W. A. Cunnington and C. L. Boulenger . . 516 



The Atottiic Weight of Cobalt.— F. H. Parker and ' 



F. Peake Sexton 316 



Single-Plate Colour-Photography. By C. J 317 



Centenary of the Geological Society 317 



Dr. August Dupre, F.R.S. By C. S 318 



The British Association at Leicester 318 



Inaugural Address \,y Sir David Gill. K.C.B., 

 LL.D., D.Sc, F.R.S., Hon. F.R.S.E., &c.. 



President of the Association 319 



Section A. — Mathematics and Physics. — Opening 

 Address by Prof. A. E. H. Love, M.A., D.Sc, 



F.R.S., President ofthe Section. {I//iistiated.) 327 



Notes 332 



Our Astronomical Column : — 



Astronomical Occurrences in August 336 



Daniel's Comet (igo?;/). (Illustmled.) 336 



The Heliomicromcter 336 



Searchcphemerides for Comet 1894 IV. (E. Swift) . 337 



A Quickly Changing Variable Star 337 



The Variation of the Pole 337 



University Reform 337 



Archaeological Explorations in Chinese Turkestan. 339 



New High Vacuum Pump. [Uluilraliil.) 340 



The Cause of Earthquakes . 341 



University and Educational Intelligence 341 



Societies and Acadenaies 342 



NO. 1970 VOL, 76] 



