Societies and Academies

    Abstract

    PARIS. Academy of Sciences, July 11.—The president announced the death of M. -Leffler, correspondant in the Section of Geomerry. E.—Cartan: The Rieman forms of geometries with semi-simple fundamental group.—G. Pfeiffr Systems of partial differential equations of the first order with several unknown functions possessing the integral of Hamburger.—Soula: The comparison of the two functions ∑anzn and ∑zn/an.—Ernest Esclangon: Observations of the partial eclipse of the sun of June 29, 1927, made at the Strasbourg Observatory. The results of measurements of the times of first and second contacts are given. The weather conditions were very favourable.—Th. Moreux: Observations of the eclipse of the sun of June 29, 1927, at Bourges.—Raoul Ferrier: The limit of application of the theory of the vector potential.—P. Lasareff: The law of viscosity of H. Le Chatelier. This formula expressing the viscosity η of glass as a function of the temperature t, namely, log (log η/η0,) = N-Mt, where η0 M, and N are constants, has been applied to the experimental data of Stott for glass, of Thorpe and Rodger for amyl alcohol, and of Deriaguine and Khananov for solutions of sugar in glycerol. The formula applies in all these cases.—Félix Michaud: Binary mixtures of volatile liquids. The case where the two components form a compound.—Emmanuel Dubois: The Volta effect. A metal becomes electronegative with respect to its initial state if it is heated (in a vacuum) to a sufficiently high temperature. The saline impurities which are normally found on the surface of a metal, and probably also in the body of the metal, may take an important part in these variations.—Nicolas Perrakis: The magnetic study of vanadium tetroxide and trioxide; the measurement of the atomic moment of trivalent and tetravalent vanadium. Whilst vanadium in the state of tetroxide possesses within two well determined intervals of temperature two different moments, the one of 8 and the other of 14 magnetons, in the state of trioxide it possesses a moment of 9.5 magnetons.—Edgar Pierre Tawil: Some observations in reso nance made on piezo-electric quartz.—R. Descamps: The natural rotatory power, in the ultraviolet, of aqueous solutions of the neutral tartrates of sodium, potassium, and ammonium.—L. Andrieux: A new method of preparing boron. On electrolysing at 1100° C. a mixture of boric anhydride (2 mol.), magnesia (1 mol.), and magnesium fluoride (1 mol.) in a carbon crucible with an iron cathode, there is obtained a deposit on the cathode which consists mainly of boron. After powdering, treating with hydrochloric acid and drying in a vacuum, this deposit contains 92 per cent, of boron.—Josef Hrdlička: The influence of the preliminary lighting and the disagreement with the law of reciprocity in photography.—Mlle St. Maracineanu: the special effect of polonium, sunlight, and electricity at high voltage on lead. The results of the experiments described suggest that the formation of a new radioactive substance occurs in the lead sheet.—Deslandres: Remarks on the preceding communication. These results are of great interest but very complex, and their exact interpretation requires much additional research.—Albert Portevin and Etienne Pretet: Study of the velocity of solution of the ultra-light magnesium alloys. A discussion of the methods available for measuring quantitatively the rate of solution.—F. Bourion and E. Rouyer: Determination of some complex compounds by the boiling-point method.—Pariselle: The polarimetric and electrometric study of the alkaline aluminotartrates. A double phenomenon of mutarotation.—Charles Prevost: A new class of tautomeric compounds; the ionic theory of tautomerism.—Mlle Jeanne Lévy and P. Weill: The reality of the semipinacolic trans position. The study of anisylmethylethylglycol. From the experiments described it is concluded that the transformation of anisylmethylethylglycol into a ketonic product different from that furnished by the aldehydoketonic transposition of anisylmethylbutaiial demonstrates the reality of the semipinacolic trans position. In the semipinacolic transposition the ethyl radical shifts more easily than the methyl radical.—Edouard Roch: The western extremity of. the Djebilets massif (Morocco).—P. Russo: The presence of Archseocyathus in the Djebel Ighoud (Western Morocco).—V. Agafonoff: The zones of the soils of France.—J. Dufay: The intensity of the green line of the polar aurora in the spectrum of the nocturnal sky.—Edouard Salles: The fixation of the radioactivity of the air by the terrestrial electric field.—Henri Coupin: The carbon nutrition of Penicillium glaucum by means of various carbon compounds of the aromatic series. Compounds of the aromatic series are much less favourable than compounds of the fatty series for securing the carbon nutrition of Penicillium glaucum, and this;is grobably true also for other moulds.—M. Bridel and Ch. Aagaard: Is melezitose a combination of saccharose with glucose? The experiments described do not confirm the view of Kuhn and van Grundherr that melezitose is a combination of saccharose and glucose.—A. Demolon and G. Barbier: Elective ionic absorption in colloidal clay.—Mme Lucie Rabdoin and Rene Fabre: Com parative researches on the glutathione content of some tissues and blood in the normal pigeon, the under-fed pigeon, and the pigeon deprived of B vitamin.—C. Arnaudi, W. Kopaczewski, and M. Rosnowski: The physico-chemical antagonisms of micro-organisms

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    Societies and Academies. Nature 120, 281–283 (1927). https://doi.org/10.1038/120281a0

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