"If you could change acqua fortis into salt—a simple enough proposition—by what reason did someone like myself scoff at the proposition that, given the right method, it was possible to turn stone into gold?"
—Iain Pears, An Instance of the Fingerpost (New York: Riverhead Books, 1998), 103
"Nitric acid, HNO3, is called acqua fortis. A clear liquid with a very pungent smell and acrid taste. Noted that it separates gold and silver (and indeed dissolves silver, though not gold). Said to be isolated by Geber, who however is probably not the Arab Ja:bir but a European taking his name. Distilled from vitriol and saltpetre."