Safety lamp, Gauzeless, no specific type, gauzeless and aluminium, use: gas testing, maker: Best's Gauzeless Lamp Co. Ltd., Leeds, 1925

This lamp, modern in 1926, which has the Mueseler chimney, and under-air feed, is designed as an official's testing lamp, and has two glasses, the inner one of which terminates at its upper end in a metal chimney. A spiral spring is coiled round the upper part of the chimney and serves to keep the chimney and the inner glass in close contact with the seating round the wick -tube. Air enters through holes in the ring supporting the bonnet, and its quantity is regulated by a hand -operated shut off of the Stokes type. The air then passes through a perforated copper cap, having holes about one -twentieth of an inch in diameter, and down the annular space between the two glasses, passing through another perforated plate at the bottom and finally emerging into the chamber surrounding the wick tube. The products of combustion pass up the chimney and escape through holes in the top of the bonnet. The pillars in front of the glass, it will be noticed, are made “blade" shaped in order to minimise the breadth of shadows cast by the light, while still retaining the protection afforded by the pillars. A half -inch flat wick is used and an electric re-lighting device is embodied in the oil cup whereby the lamp can be lit without the necessity of removing the oil cup. The lock takes the form of a spring pawl on the oil cup, which engages in teeth cut on the underside of the following -up ring below the glass. The action of the pawl prevents the oil cup from being unscrewed, unless the pawl is withdrawn from the ratchet teeth by an electro -magnet.