Italian physicist who constructed a device for accumulating a large charge by a series of inductions and groundings. He investigated the "animal electricity" of Galvani, and found that the current was generated from the contact of dissimilar metals, and that the frog leg was only acting as a detector. Using this principle, in 1800 he constructed the first battery to produce electricity. Volta's method of stacking round plates of copper and zinc separated by disks of cardboard moistened with salt solution was termed a Voltaic pile. By touching the copper and zinc disks together, Volta showed them to be oppositely charged.