Diving/smoke helmet, by Augustus Siebe. Probably a smoke helmet used by the Deane Brothers of Deptford

In the 1820s, after a period as a merchant seaman, Charles Deane developed and patented this type of helmet (made from copper and connected via a leather hose to a pumped air supply) to be used for fighting fires on land and aboard ship. The first smoke helmets were made by Augustus Siebe in 1928 and soon repurposed by the Deane brothers as diving helmets with a loosely attached suit. The ‘open’ diving suit, like a diving bell, was used in an upright position to avoid it flooding. This helmet – dating to the late 1820s - is the only known surviving example of the smoke/diving helmet that in effect launched a global diving industry and transformed underwater exploration. The Deane brothers used this type of helmet to recover artefacts from the wrecks of the Mary Rose and Royal George amongst others.