Societies and Academies

Abstract

PARIS. Academy of Sciences, December 19, 1921.—M. Georges Lemoine in the chair.—The president announced the death of M. Henry Parenty, correspondant for the section of mechanics.—E. Borel: The theory of games of chance and integral equations with symmetrical nucleus.—P. Termier and L. Joleaud: Summary of our knowledge of the Suzette layer (exact age, constitution, and extent): the question of its origin. This layer came from the Alps in the Aquitanian period, and is exclusively formed of Triassic elements.—C. Richet: The psychological unity of time.—G. Gouy: The surface tension of electrified electrolytes. In a recent communication M. Félix Michaud has proved that the surface tension of an electrolyte is not changed by the electrification of the surface, and hence raises an objection to the ionic hypothesis, since the ions, by accumulating at the electrified surface, should modify the capillary forces. The author states that it is not the ionic theory that is at fault, but the view that the charge is constituted by the ions accumulated at the surface. The latter hypothesis is inadmissible, since a small charge does not diminish the osmotic pressure in the interior of the electrolyte nor the total number of ions per unit of volume.—G. Friedel and L. Royer: Mixtures of anisotropic liquids and the identity of the stratified liquids of Grandjean with liquids of the azoxyphenetol type.—R. Lagrange: The absolute differential calculus.—J. Wolff: The series —A. Denjoy: Quasi-analytical functions with real variable.—E. Delassus: Closed articulated chains.—H. Abraham and R. Planiol: An astronomical chronograph of precision. An auxiliary electrical clock, controlled by an astronomical clock, beats tenths and twentieths of a second, and these are marked on a smoked strip by a recording galvanometer; the same instrument records the observed times on the same strip, and an accuracy of 0.01 sec. (or greater if required) is readily attained by a direct reading without a micrometer.—J. P. Lagrula: The principle and scheme of a recording chronograph with geometrical synchronisation.—J. Guillaume: Observations of the sun made at the Lyons Observatory during the third quarter of 1921. Ninety days' observations are summarised in three tables, showing the number of spots, their distribution in latitude, and the distribution of the faculæ in latitude.—E. Esclangon: The relativity of time.—J. Le Roux: Interference and reflection in a mobile system.—J. Chappuis and M. Hubert-Desprez: Electrolysis by stray currents. Two metal plates forming the electrodes were placed in sawdust or earth moistened with an electrolyte contained in a wooden box. The course of the corrosion was followed continuously by X-ray photographs.—M. Taffin: The measurement of double refraction in tempered glass.—M. Siegbahn: New measurements of precision in the X-ray spectrum. A description of an improved instrument of a type described in 1918, capable of measuring a wave-length with an accuracy of 0.002 per cent.—A. Sellerio: Analogies and differences between the total galvano-magnetic effect and its correlative thermomagnetic effect.—J. Duclaux: The mechanism of continuous-light radiation.—B. Bogitch: The expansions of some refractory materials at high temperatures. Refractory bricks of silica, bauxite, clay, chromite, and magnesia and their expansions were studied up to 1500° C. Bauxite bricks had the lowest coefficient of expansion. Silica gave an irregular curve and lost its strength at about 600° C. The highest expansions were shown by magnesia and chromite bricks, and hence these are suitable only for furnaces in continuous work.—A. Charriou: The lime carried down by ferric hydroxide precipitates. To reduce the amount of lime adsorbed by precipitated ferric hydroxide to a minimum the calcium chloride solution should be very dilute and the ammonia added only just sufficient to precipitate the iron.—M. Grandmougin; The halogen derivatives of indigo.—J. B. Senderens and J. Aboulenc: The catalytic hydrogenation of the polyphenols in the wet way. Hydroquinone, resorcinol, pyrocatechol, pyrogallol, and phloroglucinol can be reduced in the presence of nickel by hydrogen under pressure (30 to 50 atmospheres) at temperatures between 115° C. and 145° C. At higher temperatures secondary reactions take place; thus resorcinol at 120° C. gives resorcite (1:3-cyclohexanediol), but at 180° C. some cyclohexanol is produced.—M. Lespieau: Derivatives of erythritol-acetylene,