I. The influence of stress and strain on the physical properties of matter.—Part I. Elasticity (continued).—The effect of magnetisation on the elasticity and the internal friction of metals

Abstract

According to Professor G. Wiedemann, the main part of the internal friction which occurs in a torsionally vibrating wire is due to the rotation of the molecules about their axes, first to this side and then to that, as the wire vibrates to and fro. With this view the author’s own experiments on the internal friction of metals had been so far in accordance that he wished still further to test the matter by investigating the effect of magnetisation on the internal friction. The author has already made some experiments on the effect of magnetisation on the torsional elasticity of metals, but the results of these experiments did not entirely satisfy him, inasmuch as the means of eliminating the heating effect of the magnetising solenoid were imperfect. It is true that the observed changes of temperature wrought by the solenoid were comparatively small, but so also was the apparent alteration of torsional elasticity due to magnetisation; and it seemed, therefore, advisable to reopen the inquiry, and to devise more perfect apparatus, whereby the heating effect above mentioned might be entirely done away with.