A more sophisticated version of the hydrogen lamp invented by Alessandro Volta (inv. 1243). Incomplete. A glass bottle rests on a wooden box whose top is fitted with a brass collar and stop-cock. A vase-shaped glass reservoir is fitted to a brass collar above the stop-cock. The bottle contained hydrogen generated by reaction between diluted sulfuric acid and zinc. The gas was expelled from a nozzle (missing) by the pressure of the water pouring from the reservoir. An electrophorus was used to produce a spark in the spark gap. This ignited the gas, lighting the taper. The electrophorus is in the base of the instrument and can be removed for charging by rubbing with silk or cat fur. A key moved the spark-producing upper electrophorus plate and the gas stop-cock simultaneously. Provenance: Lorraine collections.