Abstract
The adiabatic tension coefficient of resistance of single tetragonal tin crystals has been determined for various orientations. Bridgman's theory, as modified by Cookson, has been extended to the tetragonal case and the experimental points found to lie within experimental error on the curves computed according to this theory. As measured directly, the tension coefficients depend both on the primary and secondary orientations of the crystal; for θ=90 they depend on the secondary orientation which is contrary to what has been found in the case of the trigonal crystals studied. The tension coefficients for specific resistance are found by allowing for the change in resistance which necessarily arises from the change in dimensions and these are found to be independent of the secondary orientation whatever the primary orientation, again contrary to what holds for trigonal crystals.