Heinke (diving equipment manufacturer)

John married Louisa Margaret Leathart in 1840 In 1818, Gotthilf Frederick Heinke opened an ironmongery shop business in London and, in 1819, he got a workshop at 103 Great Portland Street in London.

Inspired by William F. Saddler, Heinke started using solid brass for diving helmets' breastplates, instead of copper sheet.

They did not have the outer protective grills as in other helmets; thus they had better visibility for divers, and it was easier to keep the windows clean.

He introduced an additional exhaust valve on the front side of the breastplate, which is now called the "peppermill" because of the holes in its cover.

Their square breastplate made it easier for the diver to bend forwards to look for pearl oysters on the seabed.