Henry Albert Fleuss (13 June 1851 – 6 January 1933)[1] was a pioneering diving engineer, and Master Diver for Siebe, Gorman & Co. of London.

His apparatus consisted of a rubber mask connected to a breathing bag, with (estimated) 50-60% O2 supplied from a copper tank and CO2 scrubbed by rope yarn soaked in a solution of caustic potash, the system giving a duration of about three hours.

Fleuss's apparatus was first used under operational conditions in November 1880 by Alexander Lambert, lead diver of the Severn Tunnel construction project.

Trained by Fleuss, he was able to close a submerged sluice door in the tunnel which had defeated the best efforts of hard hat divers due to the danger of their air supply hoses becoming fouled on submerged debris, and the strong water currents in the workings.

Some time before the First World War, the Fleuss-Davis independent breathing set for hardhat divers appeared.