An improvement over the kerosene/paraffin bull’s-eye lantern, and before the general use of battery-operated flashlights, the carbide lamp or acetylene gas lamp was used by inspectors as a portable light source. It uses calcium carbide (CaC2) and water as its fuel. By blending the two, acetylene gas is generated and the flame produces a bright, white light. The first such lantern was patented in 1900 and subsequent lanterns were significantly improved over the next 20 years of production.
The lantern pictured here was designed for inspection use (circa1915). It is small (7 in.), portable, and features a blackout lens cover in order to let the inspector cut off the light without extinguishing the burning gas.
The term "lamp" is somewhat of a misnomer in describing these lanterns and has since became part of our idiomatic language. Lamps are generally stationary, whereas lanterns are portable and designed with hooks or hoops on top to allow them to be carried or hung.