The goldsmiths also employ a chrysocolla[1] of their own, for the purpose of soldering gold; and it is from this chrysocolla, they say, that all the other substances, which present a similar green, have received their name. This preparation is made from verdigris of Cyprian copper, the urine of a youth who has not arrived at puberty, and a portion of nitre.[2] It is then pounded with a pestle of Cyprian copper, in a copper mortar, and the name given to the mixture is "santerna." It is in this way that the gold known as "silvery"[3] gold is soldered; one sign of its being so alloyed being its additional brilliancy on the application of santerna. If, on the other hand, the gold is impregnated with copper, it will contract, on coming in contact with the santerna, become dull, and only be soldered with the greatest difficulty: indeed, for this last kind of gold, there is a peculiar solder employed, made of gold and one- seventh part of silver, in addition to the materials above-mentioned, the whole beaten up together.