But here we shall be constrained to make a little digression to serve for advertisement. In metallick dissolutions, (and let this be a maxim) we must rather take raw minerals, coming from the earth, and not the accomplished metals, and that for three reasons. The first, for that excuseth you of labour, and length of time, to calcine them, and make them dissoluble. The second, that in the dissolution of the minerall you shall find more of the salt, and shall extract it more easily, then in six of one of their chalx. And the third, for that the spirits of metall, are not yet at first so imprisoned in their corporall masse, as in the superficies within this minerall and in much greater aboundance: there when it hath passed the asperity and rigour of the fire, to separate the metal, most part of the spirits disperse themselves and the rest are drowned and barred fast in the bottome of the body: whence it is a difficulty to draw them; so that afterwards the oil is worse easie to extract from salt, in the dissolution of chalks, then of that which shall be drawn from the minerals. Take then of this _Azure_ stone for the shorter, or if you have it not of _es asium_ burned Brasse, which we make _conpellans_ of brasse, in three parts of lead, (verdigrease is too gummy and unfit) or making meal of the filings of copper, even as we said heretofore of iron, putting thereunto a little _aqua fortis_, make it clear, which will be green, as an _Emeraud_, and pursue it, in and through all as you did iron: till the salt or gum remain in the bottome congealed, proper for hollow ulcers, and many other effects of chirurgery; you may yet governe this gum with phlegme and _aqua vitæ_, as you did iron. And of the first very gumme extracted by the vineger, may thence draw an oil, as it was said of lead. In regard of the earths that remain of the dissolutions of the _aqua vitæ_, without any further dissolving of it, nor leaving any tincture therein, nor to disjoin them which is hard to do, nor to clarifie the _aqua vitæ_, but will remain impasted together as milk with dough, for they will be white, after you have dryed them well in the Sunne, or before a gentle fire. Put them upon a plate of iron, or of warmed copper: and if they fume not, it is a signe they are all deprived of their spirits. Yet put them in a cornue, with a naked bottome among coals, and perfect the drying of them; then at last give a fire of calcination. Cast _aqua vitæ_ thereon to dissolve that which you can; and evacuating the dissolution, perfect to dry the moisture which may thereof remain giving againe fire of calcination in the end: and againe putting _aqua vitæ_ thereon to perfect the extraction of all the salt therein remaining, which will be perfected in the third or fourth reiteration. I have put you to an addresse of great effects, where I do not pretend to lead you by the hand any further, not to injure good and curious spirits, that by long labours and perquisitions