If you have a good quantity of it, that you may distill a spirit thereof, you will get not only an acid (or sowre) but also a volatile spirit, which in the infirmities of the brain is most excellent; that which in the distilling remains behind, may be reduced again into a body, so that you lose nothing of the silver, save onely that which is turned into spirit. Moreover, the acid (or sowre) oyl of common Vitriol, doth precipitate all metals and stones of beasts or fishes; also pearls and corals, they being first dissolved in spirit of salt or of Nitre, and maketh fair light powders of them (which by the Apothecaries are called Magisteries) much fairer than by precipitation with salt of Tartar is done, especially of corals and pearls, such a fair glistering and delicate powder is made; and likewise also of mother of pearl, and other shels of snailes, that it giveth as fair a gloss to them, as the fairest oriental pearls have; which way hath not been made common hitherto, but being known only to few, hath been kept very secret by them, as a singular Art. Such Magisteries commonly were precipitated out of vinegar only by salt of Tartar, which for lightness, whiteness and fair gloss are not comparable at all to ours: But if instead of the oyl of Vitriol you take oyl of sulphur, then these powders will be fairer than when they are done by the oyl of Vitriol, in so much, that they may be used for painting for a black skin. Having made mention of Magisteries, I cannot forbear to discover the great abuse and error, which is committed in the preparing of them. _Paracelsus_ in his Archidoxes teacheth to make Magisteries, which he calleth extracted Magisteries: but some of his disciples teach to make precipitated Magisteries which are different from the former. _Paracelsus_ is clean of another opinion in the preparing of his Magisteries, than others in the making of theirs: doubtless _Paracelsus_ his Magisteries were good cordial living medicines, whereas the other are but dead carkases, and although they be never so fair, white and glistering, yet in effect they prove but a gross earthy substance, destitute of vertue.