Green glass instrument in the shape of a spherical flask with a long neck. Two electrodes protruding from opposite sides are secured with sealing wax. Internally they terminated in sharp points (forming a spark gap) and externally they carried small rings. The pistol would be filled with hydrogen from a rubber bag (missing). The gas was exploded by a spark from a Leyden jar. The detonation caused the violent expulsion of the barrel stopper.
In 1776, Alessandro Volta began a series of experiments in which he used an electric spark to ignite methane (which he observed and collected in swamps) and detonate a mixture of hydrogen and air. These experiments led him to invent his electric pistol, hydrogen lamp, and eudiometer. Provenance: Lorraine collections.