Societies and Academies

Abstract

PARIS Academy of Sciences, October 30.—Vice-Admiral Paris in the chair.—The following papers were read:—Letter of Mr. Hind communicated by M. Leverrier, on the intra-Mercurial planet.—Study of the organs of reproduction in ephemera, by M. Joly.—On a new electric lamp devised by M. Sabloschkoff, by M. Denayrouze. The carbons are fixed parallel, and the short interval between them is occupied by an insulating substance which disappears along with them (as the wax of a candle disappears from the wick). Various insulating substances are used, sand, glass, mortar, lac, &c. The simplest and cheapest is a sand of pounded glass.—On the distribution of magnetism on the surface of magnets, by MM. Tréve and Durassier. The more a steel is carburetted, the more is the magnetism condensed towards its extremities; the less carburetted, the more is magnetism spread out equally over its surface. The authors are having a series of steels prepared by hardening with cold water, and they seek to formulate a simple law establishing the relation between the coercitive force and the proportion of carbon.—On the deterioration of vineyards of Côte-d'Or, by M. du Merisel. —M. Wery submitted an apparatus for ventilating apartments and mines, or increasing the draught of chimneys.—On the rotatory polarisation of quartz, by MM. Soret and Sarasin. They extend their observations to the ultra-violet rays more refrangible than the line N, and also make more precise measurements. The results are tabulated.—On the laws of vibratory motion of diapasons, by M. Mercadier. The number of vibrations of a prismatic diapason is proportional to its thickness and inversely as the square of its length. The isochronism of vibrations is not absolutely rigorous; the duration of the period depends on the amplitude and the temperature. In using a diapason as chronograph or interrupter, the instrument will not give results quite identical unless you operate at the same temperature and give the vibrations the same amplitude. If (as is generally the case) one does not need complete identity and large amplitudes, then provided an amplitude of 2 to 3 mm. be not exceeded, and one operate at temperatures little different, one is certain to have the same number of periods per second to nearly 0'0001.—Chemical reactions of gallium, by M. Lecoq de Boisbaudran. Inter alia, further experiment confirms the opinion, that oxide of gallium is more soluble than alumina in ammonia. Carbonate of soda only precipitates indium after gallium. Chloride of gallium is very soluble and deliquescent. A slightly acid solution of it dried at a mild heat, gives needles or crystalline lamellae, which act strongly on polarised light. Sulphate of gallium is not deliquescent. —On terephtalic aldehyde, by M. Grimaux. —On the simultaneous formation of two trioxyanthraquinones and the synthesis of anew isomer of purpurine, by M. Rosenstiehl.—On the electric apparatus of the torpedo (third part), by M. Rouget. In the electric discs, besides ramifications of nerve-fibres and the reticulated nervous plate, one finds only vessels and cell-elements, nbrillse and membranes belonging all to the connective tissues. M. Rouget offers a theory as to the mechanism by which the nervous elements produce electrical effects. —On the phenomena of division of the cellular nucleus, by M. Balbiani.—Variations ot the electric state of muscles in tetanus, produced by passage of a continuous current, studied by means of the induced contraction, by MM. Moral and Toussaint. In such tetanus the induced contractions (shocks, isolated or associated into a tetanus of short duration) are to be regarded as accidents, though the comparison of the two traces (inducer and induced) indicates but imperfectly the cause of these accidents. The electric state of the muscle is sensibly uniform during the whole duration of the contraction.—On some parts relating to nutrition of the embryo in the egg of the hen. The blastoderm derives its elements from the yolk, whereas at the beginning of incubation, and at least till the time of complete closure of the amnion, the embryo is developed at the cost of the albumen. —On the influence of poisoning bytthe bulbous agaric on glycremia by M. Oré.—On the employment of picric acid in treatment of wounds, by M. Curie.