A glowworm lamp lights Dr. Barlow's egg cargo.
Glowworms are creatures aboard the Leviathan that provide light when a tune on a command whistle is played. They seem to be the Darwinist equivalent to electric lights.
In the series[]
Glowworms are first introduced in Leviathan, when Mr. Rigby uses them to help Deryn and Newkirk see during a topside drill. Alek first sees them after the crash of the airship in Switzerland, and notes that they do not provide heat as an oil lamp would. When glowing, the light they provide is described as a pale green. They are used both within the skin of the airship and in lamps, both portable and in the gondala, on the Leviathan.
At first, Alek thinks that the light given off by glowworms is unpleasant or sickly looking, and he thinks so again after his fight with Deryn in Goliath. Alek eventually learns the whistles to control some of the creatures on the ship, including glowworms, but Bovril often turns on the lights for him.