On the effects of changes of temperature on the elasticities and internal viscosity of metal wires

At the outset the object of this investigation was to determine the variation, produced by rise of temperature, in the rigidity-modulus and in the Young’s modulus of wires of different metals, but the observations made for this purpose yielded what seemed to us interesting information as to the viscosity of the substances examined, and led to an extension of the research. Heretofore but little attention seems to have been paid to alteration of rigidity with temperature, though several results, of apparently very different degrees of value, are available for Young’s modulus. The earliest of these are probably those of Wertheim’s experiments, but on account of the smallness of the quantities observed it is not possible to regard them as even nearly correct.