Diving helmet made by Siebe-Gorman & Company Ltd, 19th century.

Diving helmet, 19th century.

Diving helmet, 19th century.

Deep-sea diver, Science Museum, London, 2007.

Deep-sea diver, Science Museum, London, 2007.

Deep-sea diver, Science Museum, London, 2007.

Three men wearing gas masks, c 1930s.

Animated implements in a kitchen, c 1830s.

Bellows camera, c 1880.

'The Chymist', 1650.

Resuscitator kit, English, 1774.

Resuscitator kit, English, 1774.