divided into five differing Substances, Salt, Spirit, Oyle, Phlegme and Earth; of which the three former by reason of their being so much more Operative than the Two Later, deserve to be Lookt upon as the Three active Principles, and by way of Eminence to be call’d the three principles of mixt bodies.
Next, that these Principles, Though they be not perfectly Devoid of all Mixture, yet may without inconvenience be stil’d the Elements of Compounded bodies, and bear the Names of those Substances which they most Resemble, and which are manifestly predominant in them; and that especially for this reason, that none of these Elements is Divisible by the Fire into Four or Five differing substances, like the Concrete whence it was separated.
Lastly, That Divers of the Qualities of a mixt Body, and especially the Medical Virtues, do for the most part lodge in some One or Other of its principles, and may Therefore usefully be sought for in That Principle sever’d from the others.
And in this also (pursues Eleutherius) methinks both you and the Chymists may easily agree, that the surest way is to Learn by particular Experiments, what differing parts particular Bodies do consist of, and by what wayes (either Actual or potential fire) they may best and most Conveniently be Separated, as without relying too much upon the Fire alone, for the resolving of Bodies, so without fruitlessly contending to force them into more Elements than Nature made Them up of, or strip the sever’d Principles so naked, as by making Them Exquisitely Elementary to make them almost useless,
These things (subjoynes Eleu.) I propose, without despairing to see them granted by you; not only because I know that you so much preferr the Reputation of Candor before that of subtility, that your having once suppos’d a truth would not hinder you from imbracing it when clearly made