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PARIS. Academy of Sciences, July 23.—G. Bigourdan: Some sunspot observations hitherto unpublished, made at the Paris Observatory from 1683 to 1719 by Ph. La Hire and by G. Ph. La Hire.—L. Blaringhem: The fertility of Hemerocallis fulva.—P. Helbronner: The figure of the earth deduced from the measurement of the arc of the meridian of the French Alps.—Léon Pomey: The theory of algebraical curves.—E. Cartan: The Betti numbers of spaces of closed groups. —Silvio Minetti: An upper limit of the increase of the maximum modulus of an integral function of finite genus.—R. Duchêne: The influence of lead tetraethyl on the deflagration of gaseous hydrocarbon mixtures. The effect of the addition of 5 per cent of lead tetraethyl to a hexane-air mixture, and the photographs of tho flame produced on explosion, point to the fact that the lead compound exerts an antidetonating action in a homogeneous gaseous mixture.—L. d'Azambuja: Images of the solar chromosphere obtained in the spectroheliograph with the infra-red line λ8542 of ionised calcium.—Louis Pirot: Determinations of astronomical positions by means of the prism astrolabe.—A. Launert: The action of mixtures of salts on copper. The mixtures used were potassium and strontium chlorides, potassium and barium chlorides, barium and strontium chlorides. Rods of copper were heated in these mixtures to temperatures below the eutectic points (530° C. to 725° C.), and the changes in the density and electrical resistance of the metal measured.—R. Jouaust: The phenomena of propagation of radiotelegraphic waves. The phenomenon of the aurora has been explained as being due to ionisation at a great altitude (200km. to 400 km.) caused by particles emanating from the sun. It is suggested that this same ionised layer is responsible for the reflexion downwards of the electromagnetic waves.—F. Bedeau and J. de Mare: The stabilisation of the oscillations of relaxation.—Maurice Lambrey: The absorption spectrum of nitric oxide. Completion of work discussed in an earlier communication.—Paul Soleillet: The polarisation of the resonance radiations of cadmium.—Jean Becquerel: The existence, for a uniaxial crystal, of two different magnetic rotatory powers, along the axis andalong anormal to the axis.—Armand de Gramont and Georges Mabboux: Applications of ultra-microscopic illumination to the bubble of a spherical level.—Jean Thibaud: The refractive index of glass for X-rays of great wave-length.—L. Mallet: The spectral study of the luminescence of water and carbon disulphide submitted to the gamma radiation. —G. Allard: An allotropic state of silver. Ordinary silver has been shown by the X-ray method to be cubic. The silver obtained by the action of copper upon a solution of silver nitrate examined by the powder method gives a series of lines quite incompatible with a cubic structure and has proved to be orthorhombic.—René Delaplace: The gaseous contraction of hydrogen submitted to the electric discharge. Previous work on this subject has led to the suggestion that the abnormal contractions observed are due to a polymerisation of the hydrogen. In the experiments described the discharge tubes were made of Pyrex glass, without tap or ground joint, and cleaned by heating in a.vacuum to 400° C. A contraction was observed, but the presence of methane and of carbon monoxide was proved.—André Léaute: Results of briquetting coal by means of hydrocarbons partially dehydrogenated by sulphur.—Arakel Tchakirian: The volumetric estimation of germanic acid: studies of some hydrated forms of this acid and its salts.—Adolphe Lepape: The separation of krypton and xenon from atmospheric air. In preparing krypton and xenon by the slow evaporation of liquid air, the yields are extremely small owing to the fact that as the liquid phase diminishes the proportion of the two gases escaping with the oxygen increases. A method of reducing these losses is given. A litre of xenon and several litres of krypton have been prepared.—R. Levaillant: A new method of preparing alkyl sulphates. The reaction proposed is Cl. SO2 . OR +NO . OR′ =SO2(OR)(OR′) +NOCl, in which R and R′ are alkyl groups.—A. Morel and P. Preceptis: The reciprocal actions of picric acid and cycloglycylglycine.—G. Delépine: The age of the grits of Naranco (Asturia). The fauna of these ferruginous grits clearly points to their age as middle Devonian.—R. Esnault-Pelterie: The law of the constitution of the atmosphere. A discussion of the formulae proposed for giving the density of the air as a function of the altitude.—N. P. Péntcheff: The rare gases of thermal springs and the earthquakes of April 14 and 18, 1928, in Bulgaria. Although the amount of water issuing from the springs was changed by the earthquakes, the proportions of helium and argon remained the same.—V. Ghimpu: Contribution to the caryological study of the genus Medicago.—Maresquelle: The respiratory exchanges of plants attacked by the Uredineæ.—Laurent Rigotard: Alpine agronomy applied to the study of the formation of arable soils.—E. Miège: The presence of forms of the Inflatum type in Triticum durum.—V. Pertzoff: The lipase of the caterpillars of Galleria mellonella.—F. Rathery, R. Kourilsky, and Mile. Yv. Laurent: Insulin, folliculin, and glycsemia in the normal dog.—Philippe Fabre: Electrocardiography by means of commercial oscillographs. —Edm. Sergent, A. Donatien, L. Parrot, F. Lestoquard: The transmission of bovine piroplasmosis to Theileria dispar of north Africa by the tick Hyalomma mauritanicum.—E. Marchoux: Man is less sensitive than Macacus rhezus to the virus of yellow fever.—J. Bridré, A. Donatien, and D. Hilbert: Stovarsol, a specific against contagious agalaxy of the sheep and goat.
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Societies and Academies. Nature 122, 386–387 (1928). https://doi.org/10.1038/122386a0
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DOI: https://doi.org/10.1038/122386a0