Societies and Academies

Abstract

PARISAcademy of Sciences, October 1.—M. Peligot in the chair. -The following papers were read:-On the order of appearance of the first vessels in the shoots of Lysimachia and of Ruta, by M. Trecul.—Reply to M. Angot's last note on the system of winds in the region of the Algerian chotts, by M. Roudaire.- Boric.acid; methods of investigation; origin and mode of formation, by M. Dieulafait. Inter alia, he considers (in oppo sition to some high authorities) that the boric acid and accompanying substances in the lagoni of Tuscany and in analogous beds, are (with exception of the carbonic acid) products exclusively sedimentary, their mode of formation being fully explained from a study of the mother-waters of salt-marshes. It is unnecessary to call in any volcanic action. Boric acid seems to have existed in seas from the earliest ages, and to have been deposited wherever portions of sea got separated under suitable conditions. This occurred on an immense scale at two epochs widely apart, viz., in the trias, and at a certain horizon of the tertiary formation,- It is in the last mother-waters of salt-marshes that boric acidis concentrated.-Employment of pyritous earths for treatment of phylloxerised vines, by M. Dufresnoy.—Integrals of oblique developers of any order, by Abbæ Aoust.—Discovery of oxygen in the sun, and new theory of the solar spectrum, by Prof. Draper.—Note on the magnetisation of tubes of steel, by M. Gaugain. If a neutral cylindrical bar of steel, at ordinary temperature, be introduced into a magnetised tube of steel and withdrawn after a few seconds, it will be found weakly magnetised in the same sense as the tube. But if, after insertion, the system be heated with a lamp to about 300 deg., allowed to cool, and the core then drawn from the tube, the tube will be found to have lost a large part of its original magnetism, and the core to have taken an inverse magnetism.—On the exact measurement of the heat of solution of sulphuric acid in water, by M. Croulle-bois. The hitherto divergent results are attributed to a fact observed by M. Kirchhoff, viz., that the thermal effect is intimately connected with the tension of aqueous vapours emitted by the solution, and consequently with the temperature. Taking this into account the author gives a table of calories corresponding to different temperatures from 10° to 24°.—Continuation of researches on the effects of electric currents of high tension, and their analogies to natural phenomena, by M. Plantæ. This relates to effects had on placing the positive electrode of a battery of 800 secondary couples in distilled water, and bringing the negative platinum wire near the surface, a column of water having been inserted in the circuit to obviate fusion. A small globe of fire appears, taking an ovoid form when the electrode is raised a little, while a number of blue luminous points in concentric circles are seen at the surface of the water. Rays presently start from the centre and join the points; they go into gyration in one direction or the other, and describe spirals; sometimes they disappear on one side. Lastly, with increased velocity of. gyration, all vanish, and only the blue concentric rings are left. The experiment bears on the formation of globular lightning.—Some new researches on the metal davyum, by M. Kern. New researches on the density confirm the former. From preliminary experiments the equivalent is shown to be greater than 100, and probably near 150-154.—New modes of formation of oxide of ethylene, by M. Greene.— Note on the wire-drawing of platinum, by M. Gaiffe. He has got stronger fine wire by excluding atmospheric dust more completely.—On the fecundation of echinoderms (continued), by M. Fol.—Metamorphoses of cantharides (Caniharis vesicatoria), by M. Lichtenstein.—On the mutual antagonism of atropine and muscarine, by M. Prevost. He asserts (contrary to some) that large doses of muscarine will produce toxical effects in animals previously atropinised.—Trajectory of the bolide of June 14, 1877, by M. Gruey.—Meteorological observations in a balloon, by MM. Tissandier. They found a layer of air 400 m. thick, at a height of 400 m., moving pretty rapidly between two other layers almost motionless; a rare phenomenon.—On a halo observed at Brest on August 31, 1877, by M. Salicis.—Reflections on the meteorological works of M. Brault, by M. Buys-Ballot.