Societies and Academies

Abstract

PARIS. Academy of Sciences, September 6.—M. Bouchard in the chair.—The theoretical tides of the geoid, on the hypothesis of an absolute rigidity of the earth: Ch. Lallomand. Defining the geoid as the surface of mean level confining a volume equal to that of the globe, the mean tides at the equator are worked out for both the solar and lunar waves.—The Brownian movement and molecular constants: Jean Perrin and M. Dabrowski. Experiments have been made on two emulsions of different substances containing minute particles in suspension. The results are applied to determine the constant N of Avogadro in Einstein's formula, and also in a formula based on the distribution of the particles under the action of gravity. The former leads to a value of 70×1022, and the latter to 70.5×1022. The close accord of these results is a striking confirmation of the kinetic theory on which the formulge are based. The most probable value of the charge of the electron e from these values is 4.1×10.10.—Calorimetric and cryoscopic constants of mercuric bromide: M. Guinchant. The measured latent heat of fusion gives a cryoscopic constant according to van't Hoff's formula of 403; actual cryoscopic determinations in various solvents furnished a constant of 283 to 407, the average value being 340.—The life of fungi in fatty media: A. Roussy. For various moulds it was found that fatty substances were capable of replacing carbohydrates in culture media. The concentrations of fat most favourable for growth of the moulds were determined.—Some wild yams of Madagascar: Henri Jumelie and H. Perrier de la Bathie.—The experimental transmission of exanthematic typhus by the body louse: Charles Nicollc, C. Comte, and E. Conseil.—The geological structure of the peninsula of Cape Bon, Tunis: A. Allemand-Martin.