This investigation was carried out for the purpose of extending to other substances an inquiry into the effect of an electric current on Young's Modulus, which was carried out by Miss Noyes on a steel wire at Cornell University, and described in the Physical Review, No. 4, vol. ii. In the investigation of Miss !Noyes, the wire under examination was heated by a coil, the current being supplied by a storage battery. To vary the method of heating, the current was also sent through the wire with the expectation that the same effects would be obtained as when the wire was heated by the coil. This, however, was found not to be the case, and Professor Nichols, under whose superintendence the investigation was carried out, in his Laboratory Manual of Physics, vol. ii. p. 293, states that an extension of the inquiry to other materials than iron would be of interest.