Academy of Sciences, October 23.-The greater part of the communications read at this meeting were devoted to chemical subjects. Of mathematical papers only one was presented-* namely, a continuation of M. Chasles' memoir on the determina* tion of a series of groups of a certain number of points on, a geometrical curve.-A note was read by M. J. Bertrand on the mathematical theory of dynamical electricity, and a memoir by?. E. Mathieu on the integration of equations to the partial differences of mathematical physics.-M. du Moncel presented some observations relating to a recent communication by M. Ruhmkorff upQn some experiments in magneto-electric induction, in which he claimed to have already ascertained and published facts analogous to those of the German author. -M. P. A. Favre read a continuation of his thermic researches upon the electrolysis of the hydracids.-A fifth letter from Father Secchi on the various aspects of the protuberances and other remarkable parts of the surface of the sun was read, in which he describes the results of simultaneous observations made by himself at Rome, and by M. Tacchini at Palermo.-M. Secchi also presented a note on a new method of observing the eclipses and passages of Venus, by means of a spectroscopic apparatus modified by having at a distance of about 20 centimetres in front of the spectroscope, an additional prism having its refringent angle parallel to the fissure.-The chemical papers were as follows:-a theory of simple reactions limited by inverse action, and an application of the same to the transformations of phosphorus, by M. J. Lemoine. -Researches in chemical statics, by M. Stas, containing a discussion of the phenomena which occur in the precipitation of dilute solutions of salts of silver by hydrochloric, hydrobromic, and hydriodic acids, and by chlorides, bromides, and iodides. This paper contains some results of great importance in the analysis of bodies containing silver.-The conclusion of the second part of M. Berthelot's investigation of the ammoniacal salts.-A note on the transformation of glucoses into monatomic and hexatomic alcohols, by M. G. Bouchardat, communicated by M. A. Wurtz. The author acts upon the glucoses by means of an amalgam of sodium. He describes its action upon glucose and sugar of milk.-A note on the hexabromide and hexachloride of silicium, by M. C. Friedel, ako presented by M. A. Wurtz; and a note on the method of determining the gases evolved by an explosion of nitroglycerine, by M. L. L'Hote, presented by General Morin. From the researches of the last-mentioned author it appears that 1 gramme of nitroglycerine produces 284 cub. centim, of gas, containing by volume 4572 of carbonic acid, 20*36 of binoxide of nitrogen, and 33 '92 of nitrogen.-M. Elie de Beaumont called attention to some specimens of native phosphate of lime from Caylux and Cajare, and noticed the importance of these deposits for agricultural purposes. M. Combes also remarked upon this subject.-M. Chapelas presented a note on a remarkable meteor observed during the night of the 19th October.