Societies and Academies

Abstract

PARIS. Academy of Sciences, August 31.—M. P. Appell in the chair.—G. Bigourdan: Observation of the eclipse of the sun of August 21, 1914. The times of the commencement and end of the eclipse were observed under unfavourable conditions.—E. Vallier: Internal ballistics. Various formul from the recent work of N. Zaboudski. — Experiments on the gas pressures and projectile velocities in 3-in. (76.2 mm.) cannon. Approximate formuæ are deduced for the velocities and pressures as functions of the weight of the explosive, weight of the projectile, length of the powder chamber, and thickness of the band of explosive.—Kr. Birkeland and M. Skolem: Calculation of the lines of equal intensity in the zodiacal light, on the supposition that it arises from the light diffused by a nebula of electrons or of radiant matter of solar origin. The formuke deduced are illustrated graphically in seven diagrams—H. Bourget: Partial eclipse of the sun of August 21 observed at the Observatory of Marseilles. The first and second contacts were observed under good conditions.—D. Saint.Blancat and L. Montangerand: Observation of the partial eclipse of the sun of August 21, 1914, at the Observatory of Toulouse. The times of first and second contacts are given.—I. Tarazona and V. Marti: Observation of the eclipse of the sun of August 20 21, 1914, made at the astronomical observatory of the University of Valentia (Spain). J. J. Landerer: The total eclipse of the sun of August 20–21, 1914.—L. Bouchet: New determinations of Poisson's coefficient for vulcanised indiarubber. The pressures were produced by electrostatic means. The value found for Poisson's coefficient was appreciably equal to 0.5, signifying that indiarubber is incompressible.