In Vitriol, the better part (Copper and Iron) is the least, which is precipitated and separated from the courser and greater part, _viz._ Salt; But, in Tartar, the courser and less part is precipitated and separated from the greater and better part clarify’d: The like is in Metals. Therefore, let every one be wary in separating; and consider before, whether the better or courser part of the Metal is to be precipitated; without which Knowledge, no Man can meddle with this Business. Let also the Workman be ware, who expects any profit from his labour, of Corrosive Waters; as _Aqua fortis_, _Aqua Regia_, Spirit of Salt, Vitriol, Allom, Vinegar, _&c._ in the Solution from which no Good proceeds, as utterly destroying and corrupting all and each of them; proving the same in these words, _From Metals, by Metals, and with Metals, Metals are made perfect_. Metals are also purified, maturated and separated from their Vices, by Nitre burning up the superfluous Sulphur. And all the aforesaid perfections of metals are but particular. For every particular medicine, as well humane, as metallick, purgeth, separateth and perfecteth or amendeth by the taking away the superfluity. For a universal medicine worketh its perfections and emendations, by strengthening and multiplying the radical moisture as well of animals as metals, expelling its enemy by its own natural vertue. But thou sayst excellent examples indeed are delivered by me, but not the manner of doing them. _R._ I have delivered more then you think, although you don’t perceive it: for I am sure after my death that my books will be in greater esteem, from which it will appear that I have not sought vain glory, but the profit of my neighbour to the utmost of my power. But do not, seeing my freeness of writing, think that you may wrest many things from me. For assure your self, that although I have written many things for the publick good, yet I intend not by this means to trouble my self. For I cannot satisfy the desires of all men, nor answer their Epistles, nor inrich all men, who neither am rich my self, nor have sought riches. For although I have gotten the knowledge of these things by Gods blessing, and have tryed the truth of it in small quantity, yet have I never made experience in great store for wealth sake, being contented with Gods blessing. And let this suffice concerning the several purifications of metals according to my experience; as for that universal medicine so famous, I cannot judge of it, being a thing unknown to me; but the possibility thereof I am forc’t to affirm, being moved with the several transmutations of metals; which being unknown, it behoves us to be contented with that favour which God hath bestowed on us. For oftentimes questionless it is better to know little, for Eternal Salvations sake; for most commonly wealth and learning puff up. And pride brings to the Devil the Author of it, from whence God of his mercy preserve us.