PARIS. Academy of Sciences, October 7.—M. Lippmann in the chair.—Maurice Hamy: An arrangement of the arc with iron electrodes working with alternating currents. The spark spectrum of iron, used as a comparison spectrum, presents difficulties owing to the variations caused by slight changes in the experimental conditions. The arrangement of the arc between iron electrodes described in the present paper was designed to replace the spark as a source of the iron spectrum.—Gustave Sannia: The simple characteristics of partial differential equations with two variables.—N. Saltykow: The theorv of partial equations.—U. Cisotti: The movement of a solid in viscous liquid.—E. Me ”rigeault: The influence of the velocity of combustion on the efficiency of” a gas motor. —V. Auger: A new volumetric method for the estimation of uranium. The solution is reduced with metallic zinc and titrated with a standard solution of a ferric salt, using: ammonium thiocyanate as indicator.—Paul Gaubert: The polychroism of crystals of potassium sulphate artificially coloured.—Marcel Mirande: The presence of hydrocyanic acid in Trifolium repens. The presence of hydrocyanic acid, or of a substance giving rise to it under the action of an enzyme, was proved in the stems and leaves of this plant. None was found in the roots.—C. Dhéré and W. de Rogowski: The absorption of the ultra-violet rays by α- and β-chlorophvll and by crystallised chlorophyll. Pure chlorophylls are remarkably transparent for the ultra-violet rays.—Léopold Le Moult: The destruction of certain Hemiptera by vegetable parasites.—M. and Mme. Pierre DelanoS: The relations between the cysts of Carini of the lung of the rat and Trypanosoma lewisi. The authors conclude that the pneumocvsts of Carini represent a new parasite of the rat; thev are not connected with Trvbanosoma lewisi. —E. Foëx: The “Fibrinkorper” of Zopf, and their relations with the metachromatic corpuscles.