This peculiar device, in the collection of the Science Museum in South Kensington, London, looks like a tiny gas chamber a movie villain would use. Throw in your enemy—in this case, a small innocent canary—close the hatch, turn open the valve to let in poisonous gas from the cylinder above, and then laugh manically as the bird suffocates and die.

In reality, it’s the opposite. This device is used not to kill canaries, but to revive them. The cylinder attached to the top of the metal box contains life giving oxygen. They are known as Canary Resuscitators.