Safety lamp, Clanny, no.19 (bonnetted), from the Royal Commission on Accidents in Mines, 1879-86, c.1882

Presented by The Royal Commission on Accidents in Mines.

This is of the standard form, except that over the gauze is slipped a copper bonnet as proposed by Messrs. W. Smethurst and J. Ashworth; this bonnet is double at the top and the bottom, so as to baffle the entering air and outgoing gases respectively. Thus protected the Commissioners found that the lamp was not dangerous in an explosive mixture having a velocity of 1,500 ft. per min. Illuminating power, 0·3 candlepower A lead plug lock is fitted.