Joseph Priestley isolated oxygen in August 1774 by heating mercury oxide, calling it "dephlogisticated air"; Antoine Lavoisier recognized its role in combustion and respiration and named it "oxygen" (1777), grounding the modern chemical revolution. Monturiol explicitly cited both in his posthumous Ensayo (1891) to justify the breathable-air calculation for the Ictíneo II and the design of the anaerobic chemical furnace with potassium chlorate.