princes, suffered himself to be duped with the hopes of making gold, improved the brass-works at Buntheim, below Harzburg, and by these means brought a great revenue to the electoral treasury. Another production of zinc, artificial white vitriol, was also long prepared, used and employed in commerce before it was known that it was procured from this metal. That it was not known before the middle of the sixteenth century, and that it was first made at Rammelsberg, may with confidence be affirmed. Schluter ascribes the invention of it to duke Julius, and places it in the year 1570: but it must be somewhat older than the above-quoted account of Rammelsberg; for the author, who wrote about 1565[94], relates, that in his time one citizen only, whom he calls Henni Balder, boiled white vitriol; and it appears that this person kept the process a secret. That the invention was not then new, is evident from his adding, that what its effects might be in medicine had not been examined; but that its use in making eye-water had been known almost as early as the time when it was discovered. This agrees with another account, according to which the method of boiling white vitriol was found out at the time when Christopher Sander, whose service to the Harz is well-known, was tithe-gatherer. Honemann says that Sander was tithe-gatherer at the mines of the Upper Harz before the year 1564, but that in this year he was principal tithe-gatherer and director of the mines and melting-houses at Goslar. Sander himself, in a paper dated August 3, 1575, seems to ascribe the invention of white vitriol to duke Julius[95]. At first this salt was called _Erzalaun_, a name occasioned by its likeness to alum, but afterwards it was more frequently known by those of _Gallitzenstein_, _Golitzenstein_, and _Calitzenstein_. The latter names however appear to be older than white vitriol itself; as we find that green vitriol, even before the year 1565, was called green _Gallitzenstein_. May not the word be derived from _gallæ_; because it is probable that vitriol and galls were for a long time the principal articles used for making ink and in dyeing? I am of opinion that the white vitriol, which is produced in the mines of Rammelsberg in the form of icicles, gave rise to the discovery and manufacture of this salt. The former, so early as the year 1565, was called white native vitriol, or white _Gogkelgut_, and was packed up in casks, and in that manner transported for sale[96]. I shall not here enter into the old conjectures respecting the origin and component parts of this vitriol; but it deserves to be remarked, that Henkel and Neumann[97] observed in it a mixture of zinc, by which Brandt, a member of the Swedish council of mines, was led to prove, that, when pure, it consists of vitriolic acid and oxide of zinc; and this was afterwards confirmed by Hellot[98].