BOOK X.

UESTIONS as to the methods of smelting ores andof obtaining metals I discussed in Book IX.Following this, I should explain in what manner theprecious metals are parted from the base metals, oron the other hand the base metals from the precious 1 .Frequently two metals, occasionally more thantwo, are melted out of one ore, because innature generally there is some amount of gold insilver and in copper, and some silver in gold, copper,lead, and iron ; likewise some copper in gold, silver, lead, and iron, andsome lead in silver ; and lastly, some iron in copper 2 . But I will begin withgold.

Gold is parted from silver, or likewise the latter from the former, whetherit be mixed by nature or by art, by means of aqua valens 3 , and by powderswhich consist of almost the same things as this aqua. In order to preserve thesequence, I will first speak of the ingredients of which this aqua is made, thenof the method of making it, then of the manner in which gold is parted fromsilver or silver from gold. Almost all these ingredients contain vitriol oralum, which, by themselves, but much more when joined with saltpetre, arepowerful to part silver from gold. As to the other things that are added tothem, they cannot individually by their own strength and nature separatethose metals, but joined they are very powerful. Since there are manycombinations, I will set out a few. In the first, the use of which is commonand general, there is one libra of vitriol and as much salt, added to a third of alibra of spring water. The second contains two librae of vitriol, one of salt-petre, and as much spring or river water by weight as will pass away whilstthe vitriol is being reduced to powder by the fire. The third consists of fourlibrae of vitriol, two and a half librae of saltpetre, half a libra of alum, and oneand a half librae of spring water. The fourth consists of two librae of vitriol,as many librae of saltpetre, one quarter of a libra of alum, and three-quartersof a libra of spring water. The fifth is composed of one libra of saltpetre,

.gsm

x Vile a precioso.

“The reagents mentioned in this Book are much the same as those of Book VII,where (p. 220) a table is given showing the Latin and Old German terms. Footnotes in explana-tion of our views as to these substances may be most easily consulted through the index.

3 Aqua valens, literally strong, potent, or powerful water. It will appear later, fromthe method of manufacture, that hydrochloric, nitric, and sulphuric acids and aqua regia weremore or less all produced and all included in this term. We have, therefore, used either theterm aqua valens or simply aqua as it occurs in the text. The terms aqua fortis and aquaregia, had come into use prior to Agricola, but he does not use them; the Alchemists usedvarious terms, often aqua dissolvia. It is apparent from the uses to which this reagent wasput in separating gold and silver, from the method of clarifying it with silver and from thered fumes, that Agricola could have had practical contact only with nitric acid. It is probablethat he has copied part of the recipes for the compounds to be distilled from the Alchemistsanc | su ch works as the Probierbuchlein. In any event he could not have had experiencewith them all, for in some cases the necessary ingredients for making nitric acid are not allpresent, and therefore could be of no use for gold and silver separation. The essential in-gredients for the production of this acid by distillation, were saltpetre, water, and eithervitriol or alum. The other substances mentioned were unnecessary, and any speculationas to the combinations which would result, forms a useful exercise in chemistry, but of littlepurpose here. The first recipe would no doubt produce hydrochloric acid.