Peripateticall institutions. In the way of that eminent person and excellent philosopher Sr. Kenelm Digby. The theoricall part. Also a theologicall appendix of the beginning of the world. / By Thomas White Gent.

LESSON VIII.

Of Impassibility, Destruction, and the Accidents of Mixt bo∣dies.

1 THose bodies which are esteem'd not to suffer at all, that is, no losse; as Gold, though it melt, yet consumes not; the Asbestus stone is purifi'd by flames and not endamag'd; Hair grows not more flaccid, that is, its parts are not more loos'ned, with water; the Adamant is so call'd, because neither the hammer nor fire can master it: These have got a name, through the unskilful∣nesse of Artificers.

2. For, the Moderns have found out how a Diamant may be resolv'd to dust, nay, even melted: as also, how to make

Gold volatile: the Asbestus, in the very stone, both suffers from a very violent fire, and, when divided into hairs, is able to re∣sist only a moderate one.

3. It appears, consequentially, what must necessarily follow, if fire be apply'd to a confirm'd and establisht body: For, since some parts of a Compound are moi∣ster then the rest, the first efficacy of the fire will be exercis'd upon them; with which, if there be any fiery parts mix'd, those first fly out with the fire, and are call'd Spirits.

4. The next are the moist and more in∣sipid parts, and they are call'd Flegme: Then, the more concocted parts, in which Earth, Fire and Water are well mix'd; and they are call'd Oyls or Sulphurs, and need a strong fire to extract them.

5. That which remains uses, by the Chymists, to be washt in water: wherein they find a more solid part, which sinks down, and this they call Salt; and a lighter part that swimms a top, which they throw away as unusefull; notwithstanding, 'tis dry in the highest degree, and very effica∣cious to fix fluid bodies.

6. But, if a Compound of these two be throughly bak'd in a very strong fire, the

moisture of the Salt is liquifi'd, and the o∣ther being clasp'd into it, and, as it were, swimming in it, so condenses it into a po∣rous body, that it remains alwaies pervious to fire: and such a body is call'd Glasse or vitrify'd.

7. Whence, 'tis clear, that these bodies are in part, made, and, in part, resolved or extracted by the operation of Fire: and that they are not Elements, but Com∣pounds, containing the nature of the whole, as appears by Experience.

8. Out of what has been said, it may be understood, what a mixt body is, viz. A body coagulated of rare and dense parts, in a determinate number, bignesse, and weight.

9. And, when many such unite into one, a certain homogeneous sensible body emerges, serviceable for mans use; though it be seldome so pure, as to be unmixt with others.

10. Hence, again, it appears, that it concerns not a mixt body, of what Figure it be: since, with the same proportion of parts, it may be of any; especially, when one body is compos'd of many little ones. All things, therefore, receive their figure from the circumstances of their Originati∣on.

11. For, since the same things must be produc'd after the same manner; and those that are divers, different ways: the variety of manners occasions the variety of figures.

12. For, that which equally dilates eve∣ry way, becomes spherical; that which di∣lates irregularly, becomes like a Bowl; that which faints in growing longer, be∣comes like a Top.

13. That which cannot extend it self in length, becomes parallelly flat; that which is, in some part, defective in breadth, be∣comes a hexagon, a quadrate, &c. that which cannot dilate it self in breadth, be∣comes oblong. And thus, at large, and in generall, 'tis evident, whence proceed the figures of mixt bodies.