A Fibrous or STYRIATED ORE of Green Copperas. 'Tis white, and form'd almost like Sal Ammoniac; but hath the perfect Tast of Green Vitriol. Acids stir it not.

Besides the places mention'd, and others, Green Copperaas is plentifully made here in England, as at Debtford, and else where. The Copperas Stones or Fire-Stones are found on the Sea-shore in Essex, Hamphire, and so Westward; the best of a bright Silver-colour. For the making of Copperas, they make Beds sometimes an hundred feet long, and fifteen broad at top; well ram'd first with Clay, and then with Chalk. In these Beds the said Stones are laid about two feet thick: which by Sun and Rain, are gradually dissolv'd; and in five or six years time, begin to turn into a kind of Vitriolick Earth, which will swell and ferment like levened- Dough. And once in four years, the Bed is renewed with fresh Stones. In a Boyler containing about twelve Tuns of Vitriolick Liquor running from the Bed, they put in by degrees, about fifteen hundred pounds of old Iron; which both quickens the boyling, and prevents the setling and melting of the Copperas at the bottom of the Boyler, and of the Boyler it self. Sometimes, in stirring the Earth on the Beds, they find pieces of Native Copperas. See a particular and exact account of these Works at Debtford, communicated by Mr. Colwal, the Founder of this Musæum, and by Me published in the Philosophical Transactions. (a)(a) N. 142. Of the Nature of Vitriol, see several considerable Observations grounded on Experiment, in the same Transactions. (b) (b) N. 103. & 104. Amongst other particulars, an excellent way of purifying it from its Okre.

The three principal Parts hereof are, an Acid Spirit, fixed Salt, and Sulphur. The last, a good Hypnotick, in some Cases, where Opium is not safe.

Native Vitriol, saith Ambrosinus, (c) (c) Aldrov. Mus. Met. given to the quantity of ʒj in any convenient vehicle, is a great Remedy in Germany and Hungary for the Plague. Blew Vitriol of excellent use against Venereal Ulcers. Both of this, and the Green, is made the Powder called Sympathetick; the Description whereof may be seen in Papinius, and out of him in Wormius. I doubt not, but that the Stiptick Liquors of Mr. Lyster and of Mr. Deny, are both made of Vitriol.