Known in French as an eprouvette (‘test tube’), this device tested how much of a certain type of gunpowder was needed to fire a standard ball. Range was measured by the distance travelled, whilst the power was measured by how many notches were reached on the wheel. This pistol-shaped flintlock type dates to the late 18th century and is inscribed with the name 'CLAUDE REVACHON', a rifleman in Napoleon’s army.