Societies and Academies


    PARIS Academy of Sciences, September 12.—M. Wurtz in the chair.—The following papers were read:—Remarks on a memoir of MM. Lœwy and Perigaud on flexure of telescopes, by M. Villarceau.—On the comparative qualities of water of the Isère and of the Durance, as regards irrigation and provision of soil, by M. de Gasparin. He compared the constitution of the liquids at paints where all the affluents were united, and at different epochs. The two rivers are closely alike as to the quality of the slime they deposit, that of the Isère being only a little more argillaceous (which slightly favours the state of suspension). Now the Durance is largely utilised for irrigation, and enriches the departments of Bouches-du-Rhône and Vaucluse especially with fertile soil; and it is suggested that a like benefit should be derived from the Isère, in Isère and Drome.—On a new mode of exploitation of mines of sulphur, by MM. de la Tour du Breuil. They apply the principle of raising the boiling point of water by means of a dissolved salt. Chloride of calcium is so used; the bath containing 66 per cent, of it. The apparatus consists of two rectangular vessels coupled and inclined. When the operation is terminated in one, the boiling liquid is directed into the other, which is previously filled with ore. While liquation is going on (which takes about two hours) the first vessel is emptied and re-charged. One furnace suffices. The sulphur produced is very cheap (about five francs a ton) and pure. Fusion is possible all the year, as no sulphurous acid is produced; and the extraction is very complete.—The Secretary called attention to the subscription opened for a statue to Lakanal at Foix (Ariège).—On radiophony produced by lampblack, by M. Mercadier. Not only is lampblack the best thermophonic agent at present, but it is susceptible, like selenium, of playing the rSlt of the electric photophone. Instead of selenising one of the faces of his metallic double-spiral receivers, M. Mercadier covers it with lampblack, and they give good effects with intermittent solar, electric-light, and even gas, radiations. When exposed in dark to a copper plate gradually heated with an oxyhydrogen blowpipe, no sound is heard in the telephone till the plate is raised to a dull red; then it gradually increases in intensity. The author is disposed to consider the phenomenon photophonic rather than actinophonic. The resistance of these receivers diminishes as the temperature rises (from 2° or 3° to 50°), and the variation (very small) is represented nearly by a straight line.—Explanation of a contrast in double circular refraction, by M. Croullebois.—On the magnetic metalls, by M. Gaiffe. He experimented with nickel and cobalt, obtained electro-chemically and variously treated before magnetising; some bars being kept hard, others annealed, and others annealed and forged. The figures show what a comparatively great coercitive force these metals (and especially cobalt), may acquire in a pure state, while pure iron, obtained by the same means, gives inappreciable deflections in the magnetometer. The annealed and forged samples produced the greatest effects (the annealed coming next). The weak coercitive force of the metals on issuing from the galvanoplastic bath, is attributed to the presence of hydrogen in combination with them.—On metal-dehyde, by MM. Henriot and Oeconomoides.—On the rotatory power of albuminoid substances of blood-serum, and their determination by circumpolarisation, by M. Fredericq.—On permanganate of potash employed as antidote to the poison of serpents, by M. de Lacerda. A solution of snake poison having been injected subcutaneously under the thigh of a dog, and a 1 per cent, solution of permanganate of potash a few minutes after, the latter prevented all local lesion (abscess, &c.); there was merely a very slight swelling. In other cases of injection into the veins the permanganate proved a powerful antidote.— M. Maumene communicated accounts of a new apparatus for fractional dislillation, and of one for measuring the alcoholic richness of mixtures of alcohol and water.

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    Societies and Academies. Nature 24, 528 (1881).

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