John Lethbridge was the inventor of the first underwater diving suit. Lethbridge came up with this idea while working as a salvager for the East India Company. His design consisted of an airtight, oak barrel. The barrel was six feet in length and the diver had to lay flat on his stomach once the barrel was put into the waters with the help of a rope. It had two airtight holes on the sides for the hands and a hole with glass in the front for the diver’s window. During trials, Lethbridge demonstrated that the suit enabled divers to stay 12 fathoms underwater for at least 30 minutes at one go.
Once the diver comes out of the water after 30 minutes, fresh air was pumped into the suit through a vent using bellows. The used air was let out through another vent at the same time.
The suit was used mostly to retrieve material from wrecks. During Lethbridge’s first salvage operation using his invention, he recovered 25 chests of silver and 65 cannons!