Making It and Using It

Sal Ammoniac was known from antiquity as a natural sublimate collected from the soot of burning camel dung near certain Egyptian sites associated with the god Amun, whose Latinized name may lie behind the word ammonia itself, though that etymology is debated. By the medieval period it was manufactured deliberately across the Islamic world and later Europe by subliming soot, urine salts, and other nitrogenous animal waste in closed vessels, collecting the white crystalline sublimate that condensed on the vessel's cooler upper surface. It dissolves readily in water with a marked cooling effect, sublimes cleanly when heated without passing through a liquid phase, and reacts with many metal salts to form new volatile compounds, all properties that made it one of the most used reagents in the alchemical workshop.

Metalworkers used it as a flux for soldering, since it cleans oxide films from metal surfaces at soldering temperatures; dyers and textile workers used it as a mordant; and alchemists used it constantly in combination with corrosive sublimate (mercuric chloride) and other salts to make compound preparations such as sal alembroth. Its sharp, ammoniacal smell and its habit of vanishing entirely into vapor on gentle heat, leaving no visible residue unless a metal salt were combined with it, gave it a reputation as an unusually spiritual, volatile salt, one that seemed to carry an active principle rather than sitting inert like common salt.