572 BOOK XII. 



months to the air in order to soften it, it is thrown into vats and dissolved. 

 After this the solution is poured into the leaden rectangular pans and boiled 

 until it condenses into alum. The pyrites and other stones which are not 

 mixed with alum alone, but which also contain vitriol, as is most usually the 

 case, are both treated in the manner which I have already described. Finally, 

 if metal is contained in the pyrites and other rock, this material must be dried, 

 and from it either gold, silver, or copper is made in a furnace. 



VitrioP^ can be made by four different methods ; by two of these methods 



i^The term for vitriol used by the Roman authors, followed by Agricola, is 

 atramentum suiorium, literally shoemaker's blacking, the term no doubt arising from its 

 ancient (and modern) use for blackening leather. The Greek term was chalcanthon. The 

 term " vitriol " seems first to appear in Albertus Magnus (De Miner alihus, Liber v.), who 

 died in 1280, where he uses the expression " atramentum viride a quihusdam vitreolum vacatur." 

 Agricola {De Nat. Foss., p. 213) states, "In recent years the name vitriolum has been given to it." 

 The first adequate description of vitriol is by Dioscorides (v., 76), as follows : — " Vitriol 

 " (chalcanthon) is of one genus, and is a sohdified liquid, but it has three different species. 

 " One is formed from the liquids which trickle down drop by drop and congeal in certain 

 " mines ; therefore those who work in the Cyprian mines call it stalactis. Petesius calls 

 " this kind pinarion. The second kind is that which collects in certain caverns ; afterward 

 "it is poured into trenches, where it congeals, whence it derives its name pectos. The 

 " third kind is called hephthon and is mostly made in Spain ; it has a beautiful colour but is 

 "weak. The manner of preparing it is as follows : dissolving it in water, they boil it, and 

 " then they transfer it to cisterns and leave it to settle. After a certain number of days it 

 " congeals and separates into many small pieces, having the form of dice, which stick 

 " together like grapes. The most valued is blue, heavy, dense, and translucent." Pliny 

 (xxxiv., 32) says : — " By the name which they have given to it, the Greeks indicate 

 " the similar nature of copper and atramentum sutorium, for they call it chalcanthon. There 

 " is no substance of an equally miraculous nature. It is made in Spain from wells of this kind 

 " of water. This water is boiled with an equal quantity of pure water, and is then poured 

 "into wooden tanks (fish ponds). Across these tanks there are fixed beams, to which hang 

 "cords stretched by little stones. Upon these cords adheres the limus (Agricola's 'juice') in 

 " drops of a vitreous appearance, somewhat resembling a bunch of grapes. After removal, it 

 "is dried for thirty days. It is of a blue colour, and of a brilliant lustre, and is very like 

 " glass. Its solution is the blacking used for colouring leather. Chalcanthon is made in 

 " many other ways : its kind of earth is sometimes dug from ditches, from the sides of which 

 " exude drops, which solidify by the winter frosts into icicles, called stalagmia, and there is 

 " none more pure. When its colour is nearly white, with a slight tinge of violet, it is called 

 " leukoion. It is also made in rock basins, the rain water collecting the limus into them, 

 " where it becomes hardened. It is also made in the same way as salt by the intense heat of 

 " the sun. Hence it is that some distinguish two kinds, the mineral and the artificial ; the 

 " latter being paler than the former and as much inferior to it in quality as it is in colour." 



While Pliny gives prominence to blue vitriol, his solution for colouring leather must 

 have been the iron sulphate. There can be no doubt from the above, however, that both 

 iron and copper sulphates were known to the Ancients. From the methods for making vitriol 

 given here in De Re Metallica, it is evident that only the iron sulphate would be produced, 

 for the introduction of iron strips into the vats would effectually precipitate any copper. 

 It is our belief that generally throughout this work, the iron sulphate is meant by the term 

 atramentum sutorium. In De Natura Fossilium (p. 213-15) Agricola gives three varieties of 

 atramentum sutorium, — viride, caeruleum, and candidum, i.e., green, blue, and white. Thus 

 the first mention of white vitriol (zinc sulphate) appears to be due to him, and he 

 states further (p. 213) : " A white sort is found, especially at Goslar, in the shape 

 " of icicles, transparent like crystals." And on p. 215 : " Since I have explained 

 " the nature of vitriol and its relatives, which are obtained from cupriferous pyrites, 

 " I will next speak of an acrid solidified juice which commonly comes from cadmia. It is found 

 " at Annaberg in the tunnel driven to the Saint Otto mine ; it is hard and white, and so 

 " acrid that it kills mice, crickets, and every kind of animal. However, that feathery sub- 

 " tance which oozes out from the mountain rocks and the thick substance found hanging 

 " in tunnels and caves from which saltpetre is made, while frequently acrid, does not come 

 " from cadmia." Dana (Syst. of Min., p. 939) identifies this as Goslarite — native zinc sulphate. 

 It does not appear, however, that artificial zinc vitriol was made in Agricola's time. 

 Schliiter (Hueite-Werken, Braunschweig 1738, p. 597) states it to have been made for the first 

 time at Rammelsberg about 1570. 



