Effect on the resistance and thermoelectromotive force of nickel wires, of tension combined with transverse magnetization.—The wires 10 cm long and.14 cm in diameter were stretched while being magnetized transversely with a field of from 1000 to 9000 gauss. The application of tension was found to cause a marked decrease in the change due to the transverse magnetic field, both $\frac{\Delta R}{R}$ and $\frac{\Delta E}{E\Delta t}$ being decreased to half or less by a stress of 20 kg/${\mathrm{mm}}^2$.

Effect on the Hall and Nernst effects in a nickel plate, of tension in the direction of the electric and thermal currents was studied for a tension of 28.5kg/${\mathrm{mm}}^2$ and for fields up to 20,000 gauss and found to be zero. These results suggest that the Hall and Nernst effects are associated with the action of the magnetic field not on the atoms but on the free electrons, while the change of resistance and of thermoelectromotive force in a magnetic field are associated with a deformation of the atoms by the field.

Ewing's model of the ferromagnetic atom in which elliptic electronic orbits supply the magnetic control and a circular orbit the necessary Weber elements, is shown to account for the changes of length, of resistance, and of thermoelectromotive force on magnetization and the effect of tension on these changes if we assume the nickel atom is compressed in the direction of magnetization and expands at right angles, and that tension increases the stability of Weber elements with planes in the direction of the magnetic field.

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