Nikola Tesla was a Serbian American inventor, electrical engineer, mechanical engineer, physicist, and futurist. A clock worked by the electrolytic deposition and resolution of a deposit of metal upon a disc. It is the invention of Nikola Tesla. A metallic disc is mounted on a transverse axis, so as to readily rotate. It is immersed in a vessel of copper sulphate. A current is passed through the bath, the terminals or electrodes being near to and facing the opposite edges of the disc, so that the line connecting the electrodes lies in the plane of the disc. If a current is passed through the solution by the electrodes, copper is deposited on one side of the disc, and as it rotates under the influence of the weight thus accumulated on one side, the same metal as it is brought to the other side of the disc is redissolved. Thus a continuous rotation is maintained. The cause of the deposition and solution is the position of the disc; one-half becomes negative and the other positive in their mutual relations.