304 



NATURE 



\Aug. 3, 1876 



rocks of Zalasy, near Krzeszowice, which break through sedi- 

 mentary strata of Triassic age. The author, considering the micro- 

 scopic structure of these rocks, argues that they are real Tra- 

 chytes and not Porphyries, as was before supposed. This view 

 is corroborated by the construction of the felspar in regular 

 zones, enveloping one another, the numerous glass-cavities in 

 the latter as well as in quartz, while there exist no fluid- cavities 

 at all, and the abundance of glass and the want of quartz in the 

 seemingly compact base. — Dr. G. A. Koch on the Arlberg tun- 

 nel. He showed four sheets of a large and detailed geological 

 map on the scale of i : 2000, drawn from nature, representing 

 the nearest environs of the tunnel line on the Arlberg, as it 

 was marked out last summer, and illustrated it by a series 

 of sections and specimen of rock. The whole mass of rock to 

 be perforated by the tunnel belongs to the group of gneiss- 

 phyllite, which just at the Arlberg changes into quartz-phyllite, 

 wherein pure quartz abounds. The tunnel measures 6,470 

 metres in length, and attains its culmination in 1,423 metres 

 above the sea, running always nearly parallel to the direction 

 of the strata. This tunnel must be led somewhat more than 

 4*5 kilometres, or about 70 per cent, of its length, through a 

 light-coloured gneiss, which may contain in the least favourable 

 parts about one-fifth of pure quartz. Nevertheless the working 

 of this rock will present no difficulties, as it contains a great 

 deal of felspar, and the vaulting of the tunnel will only be 

 necessary in a few localities where the slates of gneiss are excep- 

 tionally very thin. A little more than one kilometre, or about 

 15 per cent, of the length of the tunnel line passes a nod-slate 

 (iCnoten-Schiefer) similar in structure to gneiss, and easily 

 wrought. Scarcely half a kilometre, or about 7 per cent, of the 

 length, belongs to a very hard, small-laminated mica-schist, con- 

 taining a great deal of quartz, and the rest, somewhat more than 

 half a kilometre, or about 8 per cent, passes a ferruginous mica- 

 schist, including garnets, that abounds more and more in quartz, 

 when coming from Stuben, the Tyrol side of the Arlberg is reached. 

 Dr. Koch also mentioned the difficulties arising from the direction 

 of the strata and the dangerous influence of water in some parts, 

 which are unfavourable to the construction of this tunnel. Finally, 

 he stated that another newly proposed line, though it passes lO'5 

 kilometres in length directly through the crystalline rocks, would 

 not only afford more security, but also would be less expensive, 

 as the total length of the railroad would be diminished, and the 

 management of it much easier, the culminating point of this 

 longer tunnel lying 108 metres deeper than that of the shorter 

 one. — Dr. R. Homes gave an account of his last summer's work. 

 In Austrian countries he mapped the valleys of old and new 

 Prax, Hohlenstein, and Sexter, then the eastern declivities of 

 the Ampezzo Valley ; in Italy he examined the valleys of Cadore, 

 Auronzo, and Comelico. The detailed geological map presented 

 by him comprises therefore nearly the same region, which Dr. 

 H. Loretz had described in the Journal of the German Geological 

 Society in 1874. — Mr. F. Groger spoke about the occurrence of 

 ores of antimony in the Isle of Borneo. 



Paris 



Academy of Sciences, July 24. — Vice-Admiral Paris in the 

 chair. — The following papers were read : — On observation of the 

 infra-red part of the solar spectrum by means of the effects of 

 phosphorescence, by M. Edm, Becquerel. Through two vertical 

 slits in a shutter are admitted two beams of parallel solar rays. 

 One beam, traversing a sulphide of carbon prism and a lens, 

 gives a spectrum which is made to fall on a phosphorescent 

 matter ; the second beam passing through a white flint prism gives 

 a spectrum, the ultra-violet part of which is thrown upon the 

 infra-red part of the first spectrum. What occurs is this : In 

 the infra-red part of the one spectrum, the impressionable 

 matter excited by the ultra-violet rays has its phosphorescence 

 destroyed, but unequally, giving an appearance of unequal illu- 

 mination. Not all phosphorescent substances give the effect im- 

 mediately, and some do not give it. The best substance was 

 found to be phosphorescent hexagonal blende. — M. Becquerel 

 gives particulars of the lines, wave-lengths, &c. — Note on 

 paraldol, a polymeric modiUcation of aldol, by M. Wurtz. — 

 Second note on the reduction of demonstrations to their most 

 simple and direct form, by M. de Saint- Venant. — Theory of the 

 modification of branches to fulfil different functions, deduced 

 from the constitution of the Amaryllidse, &c., by M. Trecul. 

 Branches may be divided into the terminated or definite, and the 

 non-terminated or indefinite. The definite branches are the leaves, 

 stipules, spaths, bracts, sepals, petals, stamens, and styles, or stig- 

 matic divisions. The indefinite branches are the roots or subter- 



ranean branches and the adventitious, the aerial branches properly 

 so-called, the peduncules, the receptacular cups, the ovaries, and 

 lastly the ovules. — Reply of M. Hira to the critique of M. Ledieu 

 in Comptes Rendus of July 10. — On the flowering of Cedrela 

 sinensis at the Museum, by M. Decaisne. A Chinese tree. 

 — M. Milne-Edwards referred to the loss sustained by the 

 Academy in the death of M. Ehrenberg, who was one of 

 the Foreign Associates on June 27 last. — On the production 

 of electric efiflavia, by M, Boillot. Two modifications of appa- 

 ratus formerly described. — Photometric researches on coloured 

 flames, by M. Gray. He describes a new method. — Note on 

 the radiometer, by M. Gaiffe. He makes one with the vanes 

 painted dull-blue on one side, dull-red on the other ; it will turn 

 either way according to the source of light and heat. Solar 

 rays move it one way, a gas flame or radiation from a heated iron 

 plate sends it the opposite. — On radiometers with vanes formed 

 of different matters, by MM. Alvergniat Bros. No. i had vanes 

 of silver and transparent mica ; No. 2, aluminium and blackened 

 mica ; No. 3, aluminium and unblackened mica ; No. 4, 

 a radiometer weighing altogether 600 mgr. ; No. 5, silver 

 and aluminium ; Nos. 6, 7, 8, mica and varnished copper, 

 green, blue, red, and yellow. Effects are described. — On the 

 cause of movement in the radiometer, by M. Sulet. He sup- 

 poses it to be a difference of temperature in the faces of the 

 vanes. A radiometer with magnetic needle retained an inva- 

 riable position of deflection four days, the light source 

 remaining constant. Action of condensed gases cannot be 

 admitted here. Decomposition of alkaline bicarbonates, moist 

 or dry, under the influence of heat and vacuum, by M. Gautier. 

 — Photographic inscription of the indications of Lippmann's 

 electrometer, by M. Marey. The opacity of the mercury column 

 is utilised to obstruct, to a variable extent; a slit through which 

 light passes to the photographic screen. The electrometer is 

 somewhat modified. M. Marey shows the curves got from varia- 

 tion of the electromotive force in the heart of a tortoise and that 

 of a frog. — On the existence of alterations in the peripheric ex- 

 tremities of cutaneous nerves in a case of pemphigoid eruptions, 

 by M. Dejerine. — On the physiological theory of fermentation, 

 and on the origin of zymases (soluble ferments), apropos of a note 

 of MM. Pasteur and Joubert on the fermentat'on of urine, by M. 

 Bechamp. — On the malacologic fauna of the islands St. Paul and 

 Amsterdam, by M. Velain. — On the reproduction of dioic Vol vox, 

 by M. Henneguy. Sexuality appears by slow degrees, the male 

 sex before the female, in proportion as the species is exhausted 

 by a sexual reproduction. — On the geological age of some metallic 

 veins, and especially veins of mercury, by M. Virlet d'Aoust. — 

 On the photography of colours, by M. Cros. — On the vertical 

 column observed above the sun on July 12, by M. Guillemin. — 

 M. Larrey presented an Italian memoir by Dr. Minich, " On the 

 antiseptic cure of wounds, and a new mode of dressing." He 

 (Dr. Minich) prefers sulphite of soda to phenic and salicylic 

 acid. 



CONTENTS Pack 



Our Oyster Fisheries 285 



Smith on Ferns. By J. G. B. . . , ?86 



Turner on the Placenta By P. S , 287 



Our Book Shelf : — 



Gross's " Elementary Treatise on Kinematics and Kinetics " . . 288 

 Lbtters to the Editor :— 



The Direct Motion in the Radiometer an Effect of Electricity. — 



Rev. Joseph Delsaulx, S J. (ffjM///?<j/raif/V«) 288 



A Brilliant Meteor.— Hon. F. A. R. Russell ; Vice-Admiral 



Eras. Ommanney 289 



D-line Spe«tra. — Major W. A. Ross 289 



Pyroxidation. — Major W. A. Ross 289 



Abstract Report to "Nature" on Experimentation on Ani- 

 mals FOR THE Advance of Practical Medicine, V. By Dr. 



Benjamin W. Richardson, F.R.S 289 



Our Astronomical Column :— 



Huth's " Moving Star" of 1801-2 291 



Venus in Inferior Conjunction 292 



The August Meteors 292 



The Kew Gardens Report 292 



On the Classification of the Vegetable Kingdom, I. By Prof. 



W. T. Thiselton Dyer (Jf«M ///Kf/ra/ic«j) 293 



Meteorology in Japan 295 



Gentilli's Tacheometer 296 



The Radiometer in France. By W. de Fonviellh 296 



Prof. Stkere's Expedition to the Philippines. By R. Bowdler 



Sharpe 297 



Science in Germany 298 



Notes 298 



Scientific Serials 301 



Societies and Academies 302 



Erratum. — Vol. xiii. p. 155, col. i, line 15 from bottom, for "mile" read 

 " rule.'' 



