Scientific Serials

Abstract

Annalen der Physik, May.—Researches on the normal cell, especially the Weston element, by W. Jaeger and St. Lindeck. This paper contains the results of an exhaustive experimental study of the Clark and Weston cells. The researches of E. Cohen had thrown some doubts upon the suitability of the Weston cell as a standard, especially in the neighbourhood of 0° C. In the present paper it is shown that these irregularities only occur about 0° C. and with the cell containing 14.3 per cent. amalgam, no trace of any irregular deviations appearing when the cell is used at 10° C. or higher temperatures. Further, if the amalgam is made slightly weaker in cadmium, 12 per cent. or 13 per cent., these irregularities near 0° disappear, and the measurements are trustworthy at all temperatures. It is concluded that the strictures of Cohen with regard to this cell are not justified, and that the Weston element is eminently suitable as a standard of electromotive force.—The calculation of isotherms, by C. Dieterici. The fundamental equation of condition of van der Waals is modified, in part empirically, without assuming that the cohesion pressure and the volume correction are determined, and the results applied to the measurements of Young on isopentane and benzene, of Ramsay and Young on ether andwater, and of Cailletet and Matthias on sulphur dioxide and carbonic acid.—Contribution to the theory of electric discharges in gases, by J. Stark.—On the variation of the dielectric constant with pressure and temperature, by J. Koenigsberger.—The constancy of the sparking potential, by K. R. Johnson.—On Jaumann's clear J-surface, by A. Korn. A discussion of a phenomenon first observed by Jaumann in a vacuum tube.—The internal friction of argon and its variation with temperature, by H. Schultze. The absolute value found for the viscosity coefficient of argon is practically identical with that previously determined by Lord Rayleigh, but the alteration of viscosity with temperature is found to be somewhat greater according to the author's experiments. The formula suggested by Sutherland gives a good approximation to the results of the experiments.—On the internal friction of gases and its change with the temperature, by P. Breitenbach. An application of Sutherland's formula to the experiments previously published by the author on the temperature coefficient of the viscosity of air, ethylene, carbonic acid, hydrogen and methyl chloride. The agreement between the calculated and experimental results is so good as to amount to a proof of Sutherland's theory.—The equilibrium figures of powders, by F. Auerbach.—On the influence of temperature on the elasticity of metals, by C. Schaefer. Experiments were carried out on nine metals, and the value of the torsion modulus measured at - 186°C., - 70° C. and about 20° C. If the temperature coefficients of the different metals are plotted as ordinates, and the melting points as abscissae, a smooth curve passes through the whole of the results.—Remarks on a paper of T. Middel on the cause of the thermal change of delicacy in balances, by W. Felgentraeger.—Liquid crystals, by O. Lehmann. A reply to some remarks of G. Tammann.—On the distribution of electricity on an ellipsoid, by G. Jaeger.