If it be mingled with Spring water, it doth make it pleasantly sowrish, and in taste and vertue like unto the natural sowre water of wells.
Also by this spirit, many diseases may be cured at home; so that you need not go to bathes afar off, for to be rid of them.
Here I could set down a way, how such a spirit may be got in great abundance for the use of bathing, without distillation, whereby miraculous things may be done, but by reason of the ungratefulness of men, it shall be reserved for another time.
Of the vertue and use of the corrosive oyl of Vitriol.
This oyl is not much used in Physick, although it be found almost in every Apothecaries shop, which they use for to give a sowrish tast to their syrups and conserves. Mingled with spring water and given in hot diseases, it will extinguish the unnatural thirst, and cool the internal parts of the body. Externally it cleanseth all unclean sores, applyed with a feather; it separateth the bad from the good, and layeth a good foundation for the cure.
Also if it be rectified first, some metals may be dissolved with it and reduced into their Vitriols, especially Mars and Venus; but this is to be done by adding common water thereunto, else it will hardly lay hold on them. The way of doing it is thus.
How to make the Vitriol of Mars and Venus.
Take of your heavy oyl, just as it came over, viz. together with its phlegm (but that the Volatile spirit be drawn off from it first) as much as you please, put it into a glass body together with plates of copper or iron, set it in warm sand, and let it boyl until that the oyl will dissolve no more of the metal, then power off the liquor, filtre it through brown paper, and put it into a low gourd glass, and set it in sand, and let the phlegm evaporate until there appear a skin at the top, then let the fire go out, and the glass grow cool; then set it in a cold place, and within some days there, will shoot fair Crystals; if of Iron, greenish; if of Copper, then something blewish; take them out and dry them upon filtering paper, the remaining liquor, which did not shoot into Vitriol, evaporate again in sand, and then let it shoot as before; continue this proceeding, until all the solution (or filtred liquor) be turned to Vitriol. This Vitriol is better and purer than the common; for it yieldeth a better Volatile spirit, and for that reason I did set down the way how to make it. There may also be made a good Vitriol of both these metals by the means of ordinary yellow brimstone; but because the making of it is more tedious, than of this here set down, I think it needless to describe its preparation in this place.
The way to make a fair blew Vitriol out of Luna (that is, silver.)
Dissolve the shavings or filings of silver with rectified oyl of Vitriol, adding water thereunto, but not so much as to Iron and Copper: Or else, which is better, dissolve calcined silver, which hath been precipitated out of Aqua fortis either with Copper or salt water; the solution being ended pour it off and filtre it, and drop into it of Spirit of urin or Sal armoniac, as long as it doth hiss, and almost all the silver will precipitate again out of the oyl, and so there will fall a white powder to the bottom; This precipitated silver together with the liquor pour into a phiall-glass, set it to boyl in sand for twenty four hours, and the liquor will dissolve again almost all the precipitated silver-calx and become blew thereby. Then pour off the solution (or liquor) and filtre it through brown paper, and abstract the moisture till a skin arise at the top; then in a cold place let it shoot to Vitriol. With the remaining liquor proceed further, as above in the preparation of the Vitriol of Iron and Copper hath been taught.