I 17 1 and fecondcafe, they contain zinc and vitriolic acid; in the third, they are compofed of iron and vitriolic acid ;• and in the laft cafe, copper and the above-mentioned acid are its integrant parts; and the firfb and fecond is vitriol of zinc, the third that of iron, and the laft that t>f COPPER; 43. There are but few inftances of a metal being found naturally united with any other acid thani the vitriolic ; arid therefore it, may be concluded,- with a pretty good de gree of certairity, that fuch metallic falls which have the above qualities are vitriolic. 44. There are inftances that the vitriolic me tallic falts cohtain more than one metal for their bafts; and in fuch a cafe, the colours of the filts are of a hue intermediate between the original colour of the fait, when it con tains but one metal. EXPERIMENT XV. 45- If a fait found in its pure and native ftate, dr its ore, be thrown on live coals, or a red-hot plate of copper, and its fumes have a fmell like garlick, and a white fpot remains on the copper-plate, or the fumes caught upon a Copper-plate look like a white powder, it is certain that the fait or ore thus examined is ARSENIC. EXPERIMENT XVI. 46. If you put into a folution fufpe&ed to contain Glauber's falt y or fal mirabile, fome fpirit of wine, a white powder will be precipitated, in cafe it really contains Glauber’s salt. C E X P E-