Hydrogen lamp invented by Alessandro Volta. Consists of a glass globe with a brass base and brass collar with stop-cock. Above the latter projects sideways a bent tube terminating in a nozzle. Next to it are two electrodes forming a spark gap and a small brass tube for holding a waxed taper. A vase-shaped glass reservoir is fitted to a brass collar above the stop-cock. The hydrogen in the globe was expelled from the nozzle by the pressure of the water pouring from the reservoir. The gas, ignited by the small spark from an electrophorus, lit the taper. Provenance: Lorraine collections.