Alchemy: Ancient and Modern / Being a Brief Account of the Alchemistic Doctrines, and Their Relations, to Mysticism on the One Hand, and to Recent Discoveries in Physical Science on the Other Hand; Together with Some Particulars Regarding the Lives and Teachings of the Most Noted Alchemists

by H. Stanley Redgrove

Helvetius’s Gold Assayed.

§ 66. “The rumour, of course, spread at once like wildfire through the whole city; and in the afternoon, I had visits from many illustrious students of this Art; I also received a call from the Master of the Mint and some other gentlemen, who requested me to place at their disposal a small piece of the gold, in order that they might subject it to the usual tests. I consented, and we betook ourselves to the house of a certain silversmith, named Brechtil, who submitted a small piece of my gold to the test called ‘the fourth’: three or four parts of silver are melted in the crucible with one part of gold, and then beaten out into thin plates, upon which some strong aqua fortis [nitric acid] is poured. The usual result of this experiment is that the silver is dissolved, while the gold sinks to the bottom in the shape of a black powder, and after the aqua fortis has been poured off, [the gold,] melted once again in the crucible, resumes its former shape. . . . When we now performed this experiment, we thought at first that one-half of the gold had evaporated; but afterwards we found that this was not the case, but that, on the contrary, two scruples of the silver had undergone a change into gold.