Note Note 7, p. 232 — BOOK VII.

[7] Minium secundarium. (Interpretatio,—menning. Pb3O4). Agricola derived his Latin term from Pliny. There is great confusion in the ancient writers on the use of the word minium, for prior to the Middle Ages it was usually applied to vermilion derived from cinnabar. Vermilion was much adulterated with red-lead, even in Roman times, and finally in later centuries the name came to be appropriated to the lead product. Theophrastus (103) mentions a substitute for vermilion, but, in spite of commentators, there is no evidence that it was red-lead. The first to describe the manufacture of real red-lead was apparently Vitruvius (VII, 12), who calls it sandaraca (this name was usually applied to red arsenical sulphide), and says: "White-lead is heated in a furnace and by the force of the fire becomes red lead. This invention was the result of observation in the case of an accidental fire, and by the process a much better material is obtained than from the mines." He describes minium as the product from cinnabar. Dioscorides (V, 63), after discussing white-lead, says it may be burned until it becomes the colour of sandaracha, and is called sandyx. He also states (V, 69) that those are deceived who consider cinnabar to be the same as minium, for minium is made in Spain out of stone mixed with silver sands. Therefore he is not in agreement with Vitruvius and Pliny on the use of the term. Pliny (XXXIII, 40) says: "These barren stones (apparently lead ores barren of silver) may be recognised by their colour; it is only in the furnace that they turn red. After being roasted it is pulverized and is minium secundarium. It is known to few and is very inferior to the natural kind made from those sands we have mentioned (cinnabar). It is with this that the genuine minium is adulterated in the works of the Company." This proprietary company who held a monopoly of the Spanish quicksilver mines, "had many methods of adulterating it (minium)—a source of great plunder to the Company." Pliny also describes the making of red lead from white.