Abstract
PARIS. Academy of Sciences, October 4.—M. Bouchard in the chair.—A method permitting the measurement of the effective temperatures, of the. stars. First results: Charles Nordmann. A development of the photometric method described by the author in a previous paper. Values are given for fifteen stars, ranging from 2980°, C. for the absolute effective: temperature of p Perseus, 5990° C. for the sun, to 60,000 for A Taurus. It is noted that the numbers found, with slight exceptions, are arranged in the order predicted by Sir Norman Lockyer from considerations based on:the appearance of the enhanced lines of the spectrum.—The hypergeometric equation: Mme. V. Myllor-Lebedeff.—The differential equations the general integral of which is uniform and admits mobile essential singularities: J. Chazy.—The measurement of high pressures deduced from the variations of resistance of conductors submitted to the pressures to be measured: A. Lafay. The change of resistance with pressure has been studied for platinum, mercury, and manganin. The first of these is not practicable for pressure measurements, since the temperature coefficient is more than 1900 times the pressure coefficient, and there are variations with different wires. Mercury gives more satisfactory results, but on account of its low temperature coefficient manganin is better.—The thermal properties of silver nitrate: M. Guinchant. Cryoscopic determinations with solutions of the nitrates of lithium, potassium, and thallium in fused silver nitrate gave cryoscopic constants agreeing closely with that deduced from the latent heat of fusion. Determinations were also made with lead nitrate, silver chloride, iodide, fluoride, iodate, and sulphate.—The examination of essence of turpentine: Paul Nicolardot and Louis Clement. Mixtures of pure essences with known quantities of resin oil, petrol, and white spirit were made, fractionally distilled both under ordinary and reduced pressure, and the physical properties of the fractions measured.— The decomposition of silver tetrachlorplatinate by water, and the preparation of fulminating platinum: Jules Jacobsen-The magnetic disturbance and aurora borealis of September 25, 1909: Alfred Angot. This magnetic disturbance is the greatest that has been observed since the commencement of observations at the Parc-Saint-Maur Observatory in 1883.
Article PDF
Rights and permissions
About this article
Cite this article
Societies and Academies . Nature 81, 480 (1909). https://doi.org/10.1038/081480a0
Issue Date:
DOI: https://doi.org/10.1038/081480a0