The royal pharmacopœea, galenical and chymical according to the practice of the most eminent and learned physitians of France : and publish'd with their several approbations / by Moses Charras, th Kings chief operator in his royal garden of plants ; faithfully Englished ; illustrated with several copper plates.

CHAP. III. Of the Preparation of Stones, and pretious Stones in general.

I Will not examine the reasons upon which some men have grounded the solid∣ness and hardness of stones, or precious stones, or the cause of their lapidifi∣cation. For their attributing the cause thereof to the proportionate union of the Alkali's with the Earth, or of both of them with Acids, or with water or juices that have a ferment in them, or a petrifying seed, is of little moment. Though we find wood, bones, and other substances to petrifie in some waters, and stones that are hid in the bodies of certain Animals, as also of men, besides that the Birth has been petrified in the wombs of some women. Nor does it signifie much that they have attributed another cause to the Acid of the air, of which we see apparent effects in Earths, which lying upon the superficies of Plains and Mountains, petrifie in succession of time. Or that they would add thereto the natural disposi∣tion which some stones have to resume their shape of stone, after they have lost it, like Plaister; or to communicate that inclination to substances mix'd with them, as Lime does. My chief intention is here to treat of the principal intentions that Chymistry practises upon stones, and precious stones.

The Mechanick imitating Chymistry, calcines in proper Furnaces, with a vio∣lent and long continu'd fire, several common stones, as certain River Flints, and certain stones whereof they make Lime for building, and those whereof they make Plaister. Chymistry sometimes calcines certain precious stones, keeping them some hours in fusion over a violent fire, as is often practis'd upon crystal; sometimes she mixes with them Niter, Salt of Tartar, or some other Salt, when she would calcine them to draw the liquor from them, as to have the liquor of Crystal. Some∣times she only heats them two or three times red hot in the fire, and quench them as often in Water, as is practis'd upon Lapis Lazuli; sometimes she dissolves them in corrosive liquors, as the Saphir in that of Vitriol, and some other precious stones in distill'd Vinegar, and which is that which they call Solntion, or potential Calcina∣tion, which is attended by other operations, of which in due place. She also makes Magisteries of these Stones, though to little purpose, in regard their vertue is much inferior to the stones from whence they are extracted.