Safety lamp

Safety lamp, Davy in case no.4, from the Royal Commission on Accidents in Mines 1879-86, maker: J. Mills and Sons, Newcastle-on-Tyne, marking: makers name, 1865-1882

This form of lamp was introduced about 1865 in the Earl of Durham's Collieries; it consists simply of an ordinary Davy lamp, enclosed in a round tin case reaching at least as high as the gauze, to protect it from strong currents. case has holes at the bottom for the admission of air and has glass either all round (as in this instance) or in the form of a window. There are screw locks to both lamp and case. The Commissioners ' tests showed this form to be safe in explosive mixtures at velocities up to 2,000 ft. per min., and this particular lamp resisted 3,000 ft. per min. The diminished amount of light was more than counterbalanced by its increased steadiness.