The safety lamp was used in the powder room of the Cairo to light the magazine. It was placed inside of a box that was part of the magazine bulkhead. It was lined with soldered sheets of copper, and when in use had a few drops of water in it. To throw as much light as possible into the magazine room, the bulkhead opening was covered by two panes of glasses. The glass closest to the magazine was framed and easily removed. A small dome or reversed funnel of copper was placed above the lamp and fitted with a pipe to redirect the smoke.
Copper, wood, L 6, Tube Dia 6, L 29.5, W 25.2, Th 2.4 cm