 Émile Gagnan

Émile Gagnan (November 1900 – 1979) was a French engineer and, in 1943, co-inventor with French Navy diver Jacques-Yves Cousteau of the Aqua-Lung, the diving regulator (a.k.a.demand-valve) used for the first Scuba equipment.The demand-valve, or regulator, was designed for regulating gas in gas-generator engines, but was found to be excellent for regulating air-supply under varied pressure conditions.