Scuba Diving

Scuba diving is underwater diving in which divers use a self-contained underwater breathing apparatus, an autonomous supply of breathing gas, that lets them operate independently of a surface air line and dive for longer and more freely than a breath-hold freediver, unlike a surface-supplied diver tethered to a hose. The English engineer Henry Fleuss built the first commercially practical scuba rebreather in 1878, a rubber mask and breathing bag fed by a copper oxygen tank that scrubbed exhaled carbon dioxide and allowed dives of roughly three hours. The decisive open-circuit breakthrough came in 1942, when the French naval officer Jacques-Yves Cousteau and the engineer Émile Gagnan combined an improved demand regulator with high-pressure air tanks to create the Aqua-Lung, patented in 1945; the physician Christian J. Lambertsen coined the acronym SCUBA in a 1952 patent, and the Australian engineer Ted Eldred introduced the single-hose regulator that same year, the configuration still standard today.