Oct. 5. 1876] 



NA TURE 



5»Q 



which the fire had spared. Examining the wood with a micro- 

 scoj-e he found the starch contents of the cells transformed into 

 a pulpy mass ; sugar was present both in the singed and the 

 unsinged trees. M. Hoffmann tried to reproduce the above 

 phenomenon artifically, but failed, doubtless through not hitting 

 the right temperature. — In another botanical paper M. Pringsheim 

 maintains that the red in Floridese is a modification of the 

 green in these plants, and not an immediate modification of 

 the chloroph\ll of phanerogams. — There is an instructive 

 abstract in the May number of M. Suess' recent work on 

 the orij^in of the Alps. He considers the members of the 

 Alpine chain to have been formed not through a pressure 

 irom below upwards, in the middle, but by a horizontal force 

 acting towards the north or north-east and capable of being 

 deflected by obstacles in its superficial action. In North America 

 and in great part from the Pacific Ocean to the Caspian the 

 same direction of force appears ; but further east, e.g., in the Red 

 Sea and Indian Valley the direction is difTerent ; in the highlands 

 of Central Asia the prevailing movement is towards the south 

 and south-we.^t. M. Suess specifies various forms of mountain- 

 formation. — We note an interesting lecture by M. Jager on the 

 significance of gill-shts in taking of food. They permit rapid 

 eicape of the water sucked in (but not of the morsel) and in a 

 backward direction, not interfering with advance of the fish. In 

 fiish that chase their prey the gills open widely. In flowing 

 water fishes have in general wider gill-slits than in still. GiU-less 

 amphibia get their food mostly in the air or on the surface. Tritons 

 take food under water awkwardly as compared with fishes, and 

 they prefer large bites that the outflow of the water may be faci- 

 litated. — In a paper on conceptions of the arrangement of atoms, 

 M. t'HofT denotes as an " unsymmetrical carbon-atom" one 

 which is combined with four different elenients or radicals. He 

 affirms that every compound containing such an atom must 

 be able to exist in at least two isomeric modifications. Fur- 

 ther, the optical activity of an organic substance is caused by 

 the presence of an unsymmctrical carbon atom. — We find in 

 the June number a brief account of Dr. Bessel's observations 

 on the intensity of heat radiation from the sun in high lati- 

 tudes. This, it appears, increases with the altitude of the 

 pole. — M. Sanson has been making observations on the excre- 

 tion of carbonic acid in the larger domestic animals. Genus and 

 species have influence on the respiration ; thus, Equidje excrete 

 more CO2 than Bovidas. Males excrete more than females ; young 

 animals more than old. Food, so long as it maintains the nor- 

 mal state, has no influence on the breathing functions, nor mus- 

 cular exertion when ended. The excretion of CO2 is directly 

 propoitional to rise of atmospheric temperature, and is inversely 

 as the barometric pressure — these two influences compensate 

 tach other. — It is shown by M. Gassend that plants lose in weight 

 under coloured glass. — From experimenting on the phenomena of 

 affinity in slow oxidation of hydrogen and carbonic oxide through 

 platinum, M. v. Meyer concludes that carbonic oxide is much 

 more strongly attracted by the platinum molecules than hydrogen, 

 and forms an envelope round these, hindering access of the 

 hydrogen molecules to the platinum, and only permitting it when 

 a great part of the carbonic oxide is oxidised. — ^July. — Seme 

 observations by M. Serpieri lead him to an explanation of the 

 zodiacal light as an electrical aurora. — The passage of electricity 

 through gases forms the subject of an investigation by M. Ober- 

 beck. 



Journal de Physique, May — August. — In studying the propaga- 

 tion of heat in crystalline and schistous bodies, M. Jannettaz has 

 improved on Senarmont's method by applying to the (larded) sur- 

 face a small sphere or truncated cone of platinum, which is 

 heated by means of a battery current. In minerals the heat is 

 propagated less easily in the direction perpendicular to a plane 

 of cleavage than parallely to this plane ; in matters of schistous 

 texture less easily in the normal direction than in directions 

 parallel to the laminse, both cases being included under the 

 general rule that heat is propagated most easily between the 

 surfaces that have most cohesion together. Planes of stratifica- 

 tion (unlike planes of schistosity,) have no influence on the posi- 

 tion of the axes of the curves oi fusion. M. Jannettaz describes 

 the plan by which he finds the orientation of the axes of the 

 thermal ellipses relatively to certain guiding lines ; he utilises 

 the doubling of the curve by means of a burefringent prism. — M. 

 Mannheim points out some new optical properties deductd from 

 a geometrical study of the surface of the wave, and M. Aiouton 

 describes a rapid means of determining the interior resistance of 

 a battery. — A new manometer for measurement of high presr 



sures is described by M. Cailletet ; it is based on the observed 

 fact that a cylindrical glass reservoir is diminished in volume 

 proportionally to the pressure en it, up to a point near that 

 of rupture, and that this deformation is not permanent. Such 

 a cylinder, with spherical calottes and a capillary tube, is 

 fillet with coloured liquid and screwed by means of a copper 

 adjutage into the top of a strong steel cylinder in which 

 the pressure is to be produced, the capillary tube projecting. 

 The pressure sends the liquid up in the latter. —-M. Marey de- 

 scribes an apparatus for showing the velocity of a ship at any 

 instant, and which is an improvement on the methods of Pilot 

 and Darcy. Two vertical tubes have their lower ends bent at 

 right angles ; the orifice of the one is turned forwards, that of 

 the other backwards (in the water). The tubes are continued 

 upwards and enter two capsules (like tho;e of aneroids) placed 

 opposite each other. The inner opposed faces of these are con- 

 nected by a bar too;hed on its upper edge, which catches in the 

 toothed wheel of a dial pointer. Two caoutchouc tubes above 

 connect the capsules with a f" tube, by which water is first 

 sucked up so as to fill the apparatus. The variations of pressure 

 produced by the ship's motion are now revealed on the dial 

 through expansion and contraction of the capsules. The advan- 

 tage of the method is that no change in depth of immersion 

 through pitching, &c., affects the position ot the pointer, but 

 any change in the ship's velocity is at once indicated. — 

 It is shown by M, Mercadier that the duration of the period 

 of a tuning-fork depends on the amplitude and the tempera- 

 ture, and that, using the instrument as chronograph or inter- 

 rupter, identical results at different times will only be had if 

 the temperature and the amplitude be the same. If, as is usual, 

 complete identity and large amplitudes be not required, then, so 

 long as an amplitude of 3 mm. to 4 mm. is not exceeded, and the 

 temperatures are little different, one is certain of having the 

 same number of periods per second to nearly O'ocoi. — M. Gemez 

 writes on determination of the temperature of solidification of 

 liquids, particularly of sulphur ; M. Duboscq describes, with 

 figures, his improved apparatus for projection of bodies placed 

 horizontally (e.g., the magnetic curves) and his transparent projec- 

 tion-galvanometer ; and M. Lippmann gives a resume o{ theories of 

 the radiometer. — M. Terquem having sought some alcohol varnish 

 which would cover glass with an almost invisible layer, on which 

 one might write or draw, recon -mends one composed of alcohol 100 

 cubic centimetres, mastic 7, sandarach 3. — M. Becquerel gives 

 an account of his experimental researches on rotatory magnetic 

 polarisation (which he has described to the Paris Academy). — 

 M. Jannettaz has observed that in the process of piercing a 

 crystal normally to the plane of symmetry, the air interposed 

 between the deformed and the traversed lamina gives nse to 

 elliptical coloured rings similar to ellipses of conductivity, and 

 he has investigated the value of the coefficients of elasticity 

 according to the radii vectors of those curves. He determined 

 the coefficients of elasticity of flexure of gypsum plates in dif- 

 ferent direction, especially those parallel to the axes of the 

 ellipses. Comparing their relations with those of the axes of 

 conductivity, he found the former to be represented by the cubes 

 of the second (the numbers being i 939 and i 247). 



Archives des Sciences Physiques et Naturelles, April- 

 August. — These numl ers contain several useful papers. There 

 is a review of Swiss geology for 1875. — The origin of the 

 Tchernozem, or black earth covering the upper parts of the 

 southern plain of Russia, from the Carpathian to the Oural, has 

 been much discussed. M. Bogdanow finds in his researches on 

 the subject, that the deposit consists, and cont.nues to be formed, 

 of the remains of vegetation both of steppes and of forests ; its 

 thickness, colour, and composition vary with the subsoil ; the 

 thickest layers are l"8 m (Murchison said 6 m.), and indicate 

 that the region has long since emerged. The Tchernozem has 

 been met with in other coun.ries, Transylvania, Moravia, North 

 America, &c. M. Bogdanow traces the history of the plains of 

 Russia and of their fauna. — M. Demole studies the action of 

 bromine on ethylenic chlorhydrine, and a new simplification of 

 the fundamental electro-dynamic law, viewed in relation to the 

 principle ot conservation of energy, is furnished in a note by M. 

 Clausius — 1. 1 reply to the question: Has the age of a tree 

 influence on the mean epoch of its foliation ? M. de Candolle 

 states that in only some few species, as the vine, the foliation is 

 retarded by aj^e. Young trees are often earlier than those of 

 tweny, thirty, or forty years of the same species ; but this may 

 be due to nearness to the ground, or to other local circumstances, 

 independent of age. Similar reasons will account for buds in the 



