Safety lamp, Mueseler no.33, Somzee's gas detecting device, use: gas detecting, from the Royal Commission on Accidents in Mines 1879-86, marking: Lampe Avertissante du Grisou systeme Somzee, 1853, Base containing bell arrangement (see 2 stroke numbers).

Presented by The Royal Commission on Accidents in Mines.

This is of the Belgian standard pattern, but provided with additions brought out in 1883 by Mons. L. Somzée for fire triers ' use, consisting of a compound helix of steel and zinc soldered together placed in the space between the gauze and the chimney. When heated to the temperature given by the combustion of a predetermined percentage of gas, the expansion of the helix causes contact with a terminal, closing a circuit comprising a small wet cell and electric bell below the reservoir. A screw lock is fitted. In practice the lamp was found to be too easily deranged.