Safety lamp, Ashworth-Hepplewhite Gray, Gray type, use: gas detecting, maker J. Davis and Son, Derby, marking: makers name, 1888

This is a development of Gray's original lamp (Inv. 1886-199); a gauze cap is introduced above the glass, which is conical for the better emission of light upwards. The internal discharge orifice into the cap is conical. The air supply through the pillars is controlled by slightly rotating a shutter on the cap, or by ferrules sliding over holes in the pillars, as patented in 1887 by Mr. J. Ashworth. These features made it one of the best ordinary lamps for fire-triers ' use. A screw lock is fitted.