Scientific Serials

Abstract

Journal de Physique, III., No. 34, Oct. 1874.—This number commences with the first portion of a paper by M. J. Bertrand, entitled “Demonstration of Theorems rdating to Electro-dynamic Actions” The object of this paper is to simplify Ampère's demonstrations of the theorems of electrodynamics.— Arrangement for obtaining projections of the metallic rays and their reversal, by M. Boudreaux. Instead of the electric light or oxyhydrogen flame, the author employs a mixture of the chlorate of the metal with one-sixth of its weight of powdered gum-lac. The mixture is inflamed in a carbon crucible placed in a lantern provided with a vertical slit. Reversals of the metallic lines are effected by allowing a beam of white light (Drummond or sunlight) to pass through the deflagrating mixture and analysing the resulting rays by prisms. By allowing the sunlight to fall only on one-half of the slit, the coincidence of bright with dark lines can be shown.—M. Mascart contributes a paper describing two pieces of apparatus for obtaining the phenomena of interference. —On the magnetisation of steel, by M. E. Bouty.—This number contains a translation of Lord Rayleigh's paper on the manufacture and theory of diffraction gratings from the Philosophical Magazine for February and March.—Sensibility of silver bromide to rays supposed to be chemically inactive, by H. Vogel, from Poggendorff's Annalen.—From the same journal there is a paper by H. Streintz, on changes in the length and elasticity of a wire under the influence of an electric current.—From the Proc. Roy. Soc. there are translations of Prof. Tyndall's paper on the transmission of sound, and Mr. Norman Lockyer's note on a new class of absorption phenomena.