We will now return to the different kinds of copper, and its several combinations. In Cyprian copper we have the kind known as "coronarium,"[1] and that called "regulare,"[2] both of them ductile. The former is made into thin leaves, and, after being coloured with ox-gall,[3] is used for what has all the appearance of gilding on the coronets worn upon the stage. The same substance, if mixed with gold, in the proportion of six scruples of gold to the ounce, and reduced into thin plates, acquires a fiery red colour, and is termed "pyropus."[4] In other mines again, they prepare the kind known as "regulare," as also that which is called "caldarium."[5] These differ from each other in this respect, that, in the latter, the metal is only fused, and breaks when struck with the hammer, whereas the "regulare" is malleable, or ductile,[6] as some call it, a property which belongs naturally to all the copper of Cyprus. In the case, however, of all the other mines, this difference between bar copper and cast brass is produced by artificial means. All the ores, in fact, will produce bar or malleable copper when sufficiently melted and purified by heat. Among the other kinds of copper, the palm of excellence is awarded to that of Campania,[7] which is the most esteemed for vessels and utensils. This last is prepared several ways. At Capua it is melted upon fires made with wood, and not coals, after which it is sprinkled with cold water and cleansed through a sieve made of oak. After being thus smelted a number of times, Spanish silver-lead is added to it, in the proportion of ten pounds of lead to one hundred pounds of copper; a method by which it is rendered pliable, and made to assume that agreeable colour which is imparted to other kinds of copper by the application of oil and the action of the sun. Many parts, however, of Italy, and the provinces, produce a similar kind of metal; but there they add only eight pounds of lead, and, in consequence of the scarcity of wood, melt it several times over upon coals. It is in Gaul more particularly, where the ore is melted between red-hot stones, that the difference is to be seen that is produced by these variations in the method of smelting. Indeed, this last method scorches the metal, and renders it black and friable. Besides, they only melt it twice; whereas, the oftener this operation is repeated, the better in quality it becomes.

(9.) It is also as well to remark that all copper fuses best when the weather is intensely cold. The proper combination for making statues and tablets is as follows: the ore is first melted; after which there is added to the molten metal one third part of second-hand[8] copper, or in other words, copper that has been in use and bought up for the purpose. For it is a peculiarity of this metal that when it has been some time in use, and has been subject to long-continued friction, it becomes seasoned, and subdued, as it were, to a high polish. Twelve pounds and a half of silver-lead are then added to every hundred pounds of the fused metal. There is also a combination of copper, of a most delicate nature, "mould-copper,"[9] as it is called; there being added to the metal one tenth part of lead[10] and one twentieth of silver-lead, this combination being the best adapted for taking the colour known as "Græcanicus."[11] The last kind is that known as "ollaria,"[12] from the vessels that are made of it: in this combination three or four pounds of silver-lead[13] are added to every hundred pounds of copper. By the addition of lead to Cyprian copper, the purple tint is produced that we see upon the drapery of statues.