Abstract
PARIS. Academy of Sciences, October 13.—M. F. Guyon in the chair.—Paul Marchal: The acclimatisation of Novius cardinalis in France. In 1912 Icerya purchasi was accidentally introduced into France, at Cap Fer-rat, and caused great damage. This plant pest has been successfully fought in California and elsewhere by the introduction of its natural enemy, Novius cardinalis, and steps were taken to acclimatise this at Cap Ferrat. The results were completely successful, the Icerya being rapidly exterminated.—Charles Depéret: The fluvial and glacial history of the Rhône valley in the neighbourhood of Lyons. Evidence is given that there were three glacial invasions of this region and not two, as currently held, leading to the formation of three fluvio-glacial terraces.—Leopold Fejér: Trigonometric polynomials.—Michel Fekete: A property of the roots of the arithmetical means of a real integral series.—N. Gunther: The cononical form of algebraical equations.—M. Tomassetti and J. S. Zarlatti: The problem of two bodies of variable masses.—Thadee Peczalski: Relations between the coefficients of expansion and the thermodynamical coefficients.—France Giraud: Certain reactions depending on reply currents.—R. Dongier and C. E. Brazier: The sound effect produced at the contact of a metallic point and the surface of a crystal or a metal by the passage of an alternating current. A faint musical note was first noted in a galena detector at the Eiffel Tower. Means have been found to reinforce this note so that wireless signals can be heard at a distance of 22 metres from the apparatus.—Ch. Gravier: An automatic method of developing photographic plates.—B. A. Dima: The photo-electric effect of metallic compounds. The photo-electric effect of analogous compounds of the same metal depends on the valency of the metal in those compounds. The four oxides of manganese offer a clear example of this.—Yugi Shibata and G. Urbain: The spectrochemistry of the complex cobalt compounds. A study of the absorption bands in the visible and ultra-violet spectra of solutions of complex cobalt salts.—M. Taffanel and Le Floch: The combustion of gaseous mixtures. Mixtures of methane and air were heated to various temperatures between 535° C. and 640° C, and the rates of combustion measured. These results are extrapolated to evaluate the inflammation temperatures of these mixtures.—P. Lemoult: Leucobases and colouring matters of diphenylethylene. The first stage of oxidation of the cyclohexylidenic leucobase, E.HI0.=C.[EH4N(CH3)2]2.
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