[Nitric acid was known in alchemical days as aqua fortis. It could dissolve almost anything but gold, which in the last quote is referred to as “Sun” or (elsewhere) “Sol,” reflecting its astrological counterpart. First are some Wikipedia entries on aqua fortis:]
“In alchemy, aqua fortis (Latin for “strong water”) is nitric acid (HNO3). Being highly corrosive, the solution was used in alchemy for dissolving silver and most other metals with the notable exception of gold, which can be dissolved using aqua regia or “regal water”. Aqua fortis was prepared by mixing either sand, alum, or vitriol, or the last two together, with saltpeter, then distilling it by a hot fire. The gas collected from this condenses into aqua fortis. It was first described by alchemist Pseudo-Geber.Aqua fortis was useful to refiners for parting or separating silver from gold and copper; to the workers in mosaic for staining and coloring their woods; to other artists for coloring of bone and ivory, which is done by tinging the items with copper or verdigris, then soaking in aqua fortis. Some also turn it into aqua regia, by dissolving in a quarter of its weight of sal ammoniac, and then use this to stain ivory and bone, of a fine purple color. Bookbinders also put it on leather, making fine marble covers for books. Diamond cutters used it to separate diamonds from metalline powders. It was also used in etching copper or brass plates. It was mixed with oil of vitriol and used to stain canes to appear like a tortoise shell by applying several coats while the cane is over hot coals. The canes were then given a gloss with a little soft wax and a dry cloth.”Pasted from <https://en.wikipedia.org/wiki/Aqua_fortis>
[And…]
“The first mention of nitric acid is in Pseudo-Geber’s De Inventione Veritatis, wherein it is obtained by calcining a mixture of niter, alum and blue vitriol. It was again described by Albert the Great in the 13th century and by Ramon Lull, who prepared it by heating niter and clay and called it “eau forte” (aqua fortis).Glauber devised a process to obtain it by distillate potassium nitrate with sulfuric acid. In 1776 Lavoisier showed that it contained oxygen, and in 1785 Henry Cavendish determined its precise composition and showed that it could be synthesized by passing a stream of electric sparks through moist air.”Pasted from <https://en.wikipedia.org/wiki/Nitric_acid>
[Instructions for working with Nitric acid (aqua fortis):]
Treatise on Metallic Medicine by Joseph Du ChesneParis, 1641
“Reduce the Sun in Mercury and calcine it with common aqua fortis, extracting the water and pouring it back three times on the feces. To finish this work properly, put the feces in a crucible on live coal till they turn all red and do not smoke any longer. Then your gold is perfectly calcined or precipitated, and all you have to do is wash it several times with dew water. When this gold lime has been thus prepared, put it in a vessel and pour over it 4 times as much good brandy. Cohobate 7 times in B. M., the last time with a small ash-fire, after which your Sun, at the bottom, will be turned into as fine a liquid as the others, and even more subtle.”Pasted from <http://rexresearch.com/duchesn/duchesne.htm#1>
