Safety lamp, Hann, Boty type, by T. Errington, Sunderland, marking: makers name, 1868

This is of the Boty type, and shows improvements patented in 1868 by Messrs. W. and E. M. Hann, of Hetton Colliery. Air is admitted directly to the flame through four rows of fine holes in the following -up ring; in order to protect them from dirt, they are supplied by one row of larger holes in the exterior ring. The gauze case is replaced by a metal cylinder with gauze cap. A screw lock is fitted. In another modification the glass was protected by wire gauze outside and a wire gauze cap.