Emile Gagnan

Emile Gagnan (born November 1900) was a French engineer and co-inventor (together with Jacques-Yves Cousteau) of the demand-valve used for the first Scuba equipment ("Aqua-Lung") in 1943. The demand-valve was designed for regulating gas in gas-generator engines, but was found to be excellent for regulating air-supply under variating pressure conditions.