Sir William Thomson’s Battery

A form of Daniell battery, of the gravity type. The receptacles are shallow wooden trays lined with lead. A thin plate of copper rests on the bottom. The zinc plate is of gridiron shape, and rests on wooden blocks which support it in a horizontal position above the copper. One tray is placed on top of the other, the upper tray resting on the corners of the zinc plate which rise above the level of the top of the flat vessel. Thus connection is assured without wires or binding posts. It is charged like a gravity battery. The density of the zinc sulphate solution should be between 1.10 and 1.30. The circuit must be kept closed to prevent deposition of metallic copper on the zinc. The entire disposition of the battery is designed to reduce resistance.