A metal, as I have said, is a natural mineral body that may be liquid, as is quicksilver, or hard although it may melt in a fire as does gold, silver copper, and lead, or become soft as does iron. Metals are found in veins, either pure or mixed with earth and stone. I shall describe the pure metal first and then take up the veins from which each is recovered, i.e., the mixed and compound minerals of that genus. The older writers have held that only gold and true quicksilver are found in veins. Pliny, who has compiled the writings of the Greeks and Latins in his Natural History, denies that silver is ever found pure. He writes that it never occurs naturally in its true form and never has the sparkling brilliancy of gold. However, all the mines of Germany cry out with one voice against this conclusion. Pure silver, copper, iron and bismuth are dug from the earth. The other two genera of “ lead” minerals 1 are found almost pure. However, the true, virgin metal created originally within the earth is either simple, such as quicksilver, always, tin and iron, almost always, and silver, commonly, or mixed with another metal, usually gold, copper, lead or bismuth. The oldest writers, Diemachus, Megasthenes, Aristeas, Herodotus and many others, have said that gold is found pure. Whenever I think about their writings the present methods of recovering gold are brought to my mind and I am always led to the . . .