The earliest known description of zinc as a metal is found in the treatise on minerals by Paracelsus, and it is he who first designates the metal by the name familiar to us. Paracelsus says: “There is another metal, zinc, which is in general unknown. It is a distinct metal of a different origin, though adulterated with many other metals. It can be melted, for it consists of three fluid principles, but it is not malleable. In its colour it is unlike all others, and does not grow in the same manner; but with its _ultima materia_ I am as yet unacquainted, for it is almost as strange in its properties as argentum vivum.” The alloy of zinc with copper which we call brass was known and much prized by the Roman metal workers, and they also knew the zinc earth, calamine, and used this in the production of brass. Who first separated the metal from the earth is unknown; so too is the original inventor of white vitriol (sulphate of zinc). Beckmann quotes authorities who ascribe this to Julius, Duke of Brunswick, about 1570. Beckmann says white vitriol was at first known as erzalaum, brass-alum, and later as gallitzenstein, a name which he thinks may have been derived from galls, as the vitriol and galls were for a long time the principal articles used for making ink and for dyeing. Green vitriol, he adds, was called green gallitzenstein. The true nature of several vitriols was not understood until 1728, when Geoffrey studied and explained them. The ideas entertained of zinc by the chemists who studied it were curious. Albertus Magnus held that it was a compound with iron; Paracelsus leaned to the idea that it was copper in an altered form; Kunckel fancied it was congealed mercury; Schluttn thought it was tin rendered fragile by combination with some sulphur; Lemery supposed it was a form of bismuth; Stahl held that brass was a combination of copper with an earth and phlogiston; Libavius (1597) described zinc as a peculiar kind of tin. The metal he examined came from India. The white oxide of zinc was originally known as pompholyx, which is Greek for a bubble or blister, nihil album, lana philosophica, and flores zinci. The unguentum diapompholygos, which was found in the pharmacopœias of the eighteenth century, and was a legacy from Myrepsus, was a compound of white lead and oxide of zinc in an ointment which contained also the juice of nightshade berries and frankincense. It was deemed to be a valuable application for malignant ulcers.