Safety lamp

Safety lamp, A1, Clanny type (bonnetted), Beard and Mackie gas detector and aluminium, use: gas testing, maker: John Davis & Son (Derby) Ltd., marking: makers name, 1907

This fire-triers ' lamp has an attachment patented in 1902 by Mr. J. T. Beard and Mr. M. D. Mackie for the detection of small percentages of firedamp. It consists of a n -shaped wire soldered to a disc which is held down to the wick tube by the screw cap of the oil reservoir. Across then are six twisted platinum wires, and below them one iron wire which the flame should reach before testing. The cap to the flame caused by the presence of ignited firedamp is rendered visible by the glowing of the platinum wires, an effect partly due to occlusion. It is claimed that it will indicate from 0.5 per cent. up to 3 per cent. of firedamp according to the number of wires aglow, The lamp is a bonneted Clanny with a specially long glass blackened on one side; air admission is controlled by a horizontal shutter. A screw lock is fitted.