544 



NA TURE 



[October i, 1896 



engineering, by Prof. Robinson, beginning Monday, October 

 5 ; architecture, by Prof. Banister Fletcher, beginning on 

 Wednesday, October 7 ; experimental and practical physics, 

 beginning on Monday, October 5, under the direction of Prof. 

 Adams, !•'. R.S. ; pure mathematics — higher mathematics — 

 by Prof. Hudson, beginning on Tuesday, October 6 : and a 

 free Saturday morning class for elementary teachers — strength of 

 materials and theory of machines — by Prof. Capper, beginning 

 Saturday, October 17. Application to join any of the above 

 classes should be made, as soon as possible, to the Professors 

 who will conduct the courses. The formation of the classes 

 is a new feature of the work of the London Technical Education 

 Board, and it is one which will advance technical education in 

 the right direction. 



SCIENTIFIC SERIALS. 



Wicdentanu s Aiinakn der Physik tiitd C hemic. No. 9. — 

 Effect of light on spark discharges, by E. Warburg. This effect 

 is not a direct action, but is the consequence of the shortening of 

 a process preceding the spark discharge, and this shortening is 

 brought about by illumination. The author studied the shorten- 

 ing by applying the difference of potential more or less rapidly, 

 and finding the lowest diftcrence of potential capable of pro- 

 ducing discharge within five minutes, this being the greatest 

 delay observed. The discharge potential thus found he calls 

 the statical discharge potential, to distinguish it from the dynamic 

 discharge potential producing sparks when the current surges to 

 and fro. The experiments made by the author show that the 

 statical discharge potential is not materially influenced by illu- 

 mination. But when a difference of potential nearly seven 

 times as high is applied for a few thousandths of a second only, 

 it always produces discharge when the kathode is illuminated by 

 an arc lamp, and not in the dark. The range of potentials at 

 which discharge only takes place occasionally is very small in the 

 case of illumination, but large in the dark. This explains why 

 a telephone connected with an illuminated spark gap gives a 

 purer note than when it is not illuminated. — Electric refractive 

 indices of water and aqueous solutions, by P. Drude. For 

 oscillations of the frequency of 4 x 10'' per second the square 

 of the electric index of refraction -at 17° C. is 81 '67. Water 

 possesses slight normal dispersion, since the square is So'6o for 

 a frequency of i '5 x 10', and 83 '6 for 8 x 10*. Between 0° and 

 26° the change of n- is proportional to the temperature. It 

 decreases by o'367 per degree. At higher temperatures the 

 decrease is slower. The refractive indices of dilute aqueous 

 solutions are very nearly the same as those of water. — Dilute 

 ferromagnetic amalgams, by H. Nagaoka. In fields of less than 

 20 C.G.S. units the magnetisation of iron amalgams shosvs a 

 discontinuity at the melting-point. On heating an amalgam 

 containing 17S percent, of iron, produced by electrolysis, up 

 to its melting-point ( - 58° C), the intensity of magnetisation in 

 a field of 16 units gradually increased. It suddenly attained a 

 maximum on melting, and gradually diminished on further 

 leating. — Influence of pulling and pushing forces upon magnetic 

 'roperties, by G. S. Meyer. Cobalt also shows the effect 

 discovered in iron by Villari of a maximum of magnetic intensity 

 when under a certain force. In nickel and cobalt tension pro- 

 duces an E.M.F. identical in direction with that produced by 

 longitudinal magnetisation. — An attempt to liquefy helium, by 

 K.Olszewski. (Seep. 377. ) Helium cannot be liquefied by the 

 most powerful methods yet available. It is more permanent 

 than hydrogen, probably owing to its monatoniic structure, and 

 is on that account valuable as a thermometric substance at very 

 low temperatures. A comparison of a helium and a hydrogen 

 thermometer shows, however, that hydrogen lias normal expan- 

 sion as far as — 234'5° C. , its critical temperature, and is there- 

 fore available for thermometric use down to that point. 



Bollettiito delta SocietH Sismologi(a Italiaiia, vol. ii., iSg6, 

 No. 3. — On the Benevento earthquake of March 14, 1702, by 

 M. Baratta. A discussion of the earthquake founded on three 

 old documents recently discovered, and of its relations to the 

 Benevento earthquakes of June 16SS and September 1S85. — 

 Present state of the endogenous phenomena in the Enlian islands, 

 by A. Ricco. — Considerations on recording seismic apparatus 

 and modification of the two-component microseismograph, by 

 G. Vicentini and G. Pacher. A reprint of a paper already 

 noticed in Nature.— Summary of the principal eruptive pheno- 

 mena in Sicily and the adjacent islands during the six months 

 January to June, 1896, by S. Arcidiacono. 



NO. 1405, VOL. 54] 



SOCIETIES AND ACADEMIES. 



Paris. 

 Academy of Sciences, September 21. — M. A. Cornu in 

 the chair. — The President announced the loss that the .\cademy 

 had sustained in the death of M. Fizeau, and the meeting was 

 adjourned in consequence. 



New South Walks. 

 Linnean Society, July 29. — Mr. Henry Deane, President, 

 in the chair. — .■\ppendix to the Australian Clivinides (fam. 

 Carabidic), by Thomas G. Sloane. .Since his paper was read 

 (at the June meeting) the author has h.ad the opportunity of 

 examining the Clivinides of King's Sound, W.A., and its 

 vicinity, in the Macleay Museum. The collection comprises 

 sixteen species, of which two are described as new. — Descrip- 

 tions of new species of Australian Coleoptera, by Arthur M. 

 Lea. Two genera and thirty-four species belonging to the 

 families TencbrionidiT and Curculionidie are described as new. 

 Two very interesting species are noted — an apterous Pleroheheiis 

 and a Cossonid having an 8-jointed funicle. — Descriptions of some 

 new Araiieida- of New South Wales, No. 6, by W. J. Rainbow. 

 Eight species, comprising representatives of the si,eTier& A^epkila, 

 Epeira, Doloincdes, and Actinoups, are described as new. The 

 last named is specially interesting from the fact that it is the 

 first of the genus recorded from Australia. Five of the spiders 

 described are remarkable for their protective colouration or 

 mimicry ; in addition to these, numerous other examples are 

 instanced. After summing up all the facts recorded, the writer 

 concludes by dividing the Araiieid(e into two groups, viz. : (l) 

 (a) spiders whose colouration and {/>) formation is protective : 

 and (2) spiders that mimick, (a) animate or (/i) inanimate ob- 

 jects, and (1) whose colours are attractive. — Description of a new 

 species of Ablepharus from Victoria, with critical remarks on two 

 other Australian lizards, by A. II. S. Lucas and C. Frost. 

 Ablepharus rhodoiioides, sp.n., from Mildura, is allied \.a A. gi-eyi. 

 Gray, by the head-scaling, but in habit it resembles species like 

 A. tiiiielleri, Fischer, and A. litiealiis. Bell, which are remark- 

 able for the reduction in the size of the limbs, ,as well as in the 

 number of the digits. A. greyi, described from West Australia, 

 is recorded from the Boggabri District, N.S.W. Heinispherr- 

 iodon tasmanictim, Lucas and Frost (Proceedings, 1893, p. 227), 

 as the outcome of the examination of series of additional speci- 

 mens, is now reduced to a variety of the veiy variable Hoinolc- 

 pida casiiariiieie, D. and B. — On a new genus and three new 

 species of mollusca from New South Wales, New Hebrides, and 

 Western Australia, by John Brazier. 



CONTENTS. PAGE 



Chemistry in Daily Life 521 



Our Book Shelf: — 



Woodward: " Crystallography for Beginners " . . . 522 



Step: " By the Deep Sea " 522 



Letters to the Editor: — 



The Utility of Specific Characters. — W. T. 

 Thiselton-Dyer, C.M.G., F.R.S. ; J. T. Cun- 

 ningham . 522 



Fossil Tridacnids in the Solomon Islamls. (/lliis- 



tralcd. )— Dr. Arthur Willey ... 523 



Visual -Vid in the Oral Teaching of Deaf Mutes. — T. 



Hawksley . . 523 



International Meteorological Conference at Paris . 523 

 Armand Hippolyte Louis Fizeau. By Prof. A. Gray, 



F.R.S 523 



Notes 524 



Our Astronomical Column:— 



The Solar Rotation 526 



A New Spectroscopic Binary 527 



The \'ariable Star Z Herculis 527 



The British Association : — 



Section H— .\nthropology. — Opening .\ddress by 



Arthur J. Evans, President of the .Section . . . 527 

 Section K— Botany.— Opening Address by Dr. D. H. 



Scott, F.R.S., President of the Section 535 



The Conway Expedition to Spitzbergen 543 



University and Educational Intelligence 543 



Scientific Serials 544 



Societies and Academies 544 



