A story of doubtful authenticity concerns the then head of the U.S. Patent Office who, in 1899, is reputed to have sent his resignation to President McKinley and urged the closing of the office on the grounds that, “everything that could be invented has been invented.”

It’s the sort of comment that causes people hearing it for the first time to scoff at such arrogance, particularly if they’ve read it via the newly installed app on their smartphone. But even if the story isn’t true, it does help highlight the fact that many developments in technology that we think of as being “new” are often nothing more than refinements of an already established concept.

Rebreathers, for example, have been in use since 1878, when Henry Fleuss designed an apparatus that would allow divers access to flooded compartments and tunnels beyond the reach of a helmeted diver towing a cumbersome and restrictive umbilical air hose.

Consisting of a copper cylinder of compressed oxygen, a breathing bag (or “counter-lung”) and a “scrubber” filled with pieces of sponge rubber saturated in a caustic potash solution to remove the excess carbon dioxide, the device worked perfectly and proved its worth in several highly publicised diving projects.

Despite this initial success, the conservative attitude shown by working divers toward their equipment carried the day; rebreathers might have been invented, but they certainly weren’t accepted. Even the military was slow to appreciate their worth.

Today — more than 130 years after its debut — the rebreather is finally gaining the widespread acceptance it deserves. Already in daily use as an exploration tool for certain categories of technical diver, the basic concept has been refined and enhanced to the point where, with appropriate training, divers at every level of experience can safely enjoy the advantages that a rebreather offers.

_Diving since 1961 — with a background in military, commercial, recreational and technical diving — David Strike has dived extensively throughout the Asia-Pacific region, is a Fellow of the Explorers Club, and the organiser of the biennial OZTeK Diving Conference.___