Marsaut Safety Lamp, 1880s

Safety lamp, Marsaut, no.1, from the Royal Commission on Accidents in Mines, 1879-86, c. 1885

This lamp embodies the results of a long series of experiments carried out prior to 1885 by Monsieur. J. B. Marsaut, of Bessèges, France. The lamp resembles a bonneted Clanny type, but has three gauzes, one within the other, each slightly more conical than the one outside it; these have 900 apertures per sq. in. The gauzes are protected by a screwed -on sheet iron bonnet with a number of large holes near the lower end to admit air for combustion, and with apertures at the top above a gauze diaphragm of 400 apertures to the square inch to allow the products of combustion to escape. The illuminating power is about 0.5 candles. A vertical screw lock is fitted to the reservoir, but there is no lock to the bonnet. In Mr. Ellis Lever's competition of 1885 the lamp was one of two specially mentioned; it was also one of four most favourably reported on by the Commissioners, there being no explosion in a current moving at a velocity of 3,100 ft. per min.