Safety lamp, Gray no.1, from the Royal Commission on Accidents in Mines, 1879-86, maker: J. Cooke and Co., Birmingham, marking: makers name, 1868-1881

This lamp, which is of the underfeed type, was patented in 1868 by Mr. T. Gray, one of H.M. Assistant Inspectors of Mines, and has been developed principally as a testing lamp. The air for combustion is drawn through four tubes extending from the top to a gauze -protected space round the wick; the waste gases pass off through a metal chimney and a gauze diaphragm, and thence through perforations in the cap, which overhangs the air inlets to break up currents. Illumination, 0.3 to 0.4 candlepower A lead plug lock is fitted. The lamp was one of four most favourably reported on by the Commissioners, whose experiments showed that it could resist explosive mixtures at a velocity of 3,100 ft. per min.