But this is not all; for although I formerly told You how Little Credit there is to be given to the Chymical Processes commonly to be met with, of Extracting the Mercuries of Metals, Yet I will now add, that supposing that the more Judicious of Them do not untruly affirme that they have really drawn true and running Mercury from several Metals (which I wish they had cleerly taught Us how to do also,) yet it may be still doubted whether such extracted Mercuries do not as well differ from common Quicksilver, and from one another, as from the Mercuries of Vegetables and Animalls. _Claveus_,[21] in his Apology, speaking of some _experiments_ whereby Metalline Mercuries may be fixt into the nobler metals, adds, that he spake of the Mercuries drawn from metals; because common Quicksilver by reason of its excessive coldnesse and moisture is unfit for that particular kind of operation; for which though a few lines before he prescribes in general the Mercuries of Metalline Bodies, yet he chiefly commends that drawn by art from silver. And elsewhere, in the same Book, he tells us, that he himself tryed, that by bare coction the quicksilver of Tin or Pewter (_argentum vivum ex stanno prolicitum_) may by an efficient cause, as he speaks, be turn'd into pure Gold. And the Experienc'd _Alexander van Suchten_, somewhere tells us, that by a way he intimates may be made a Mercury of Copper, not of the Silver colour of other Mercuries, but green; to which I shall add, that an eminent person, whose name his travells and learned writings have made famous, lately assur'd me that he had more then once seen the Mercury of Lead (which whatever Authors promise, you will find it very difficult to make, at least in any considerable quantity) fixt into perfect Gold. And being by me demanded whether or no any other Mercury would not as well have been changed by the same Operations, he assured me of the Negative. [Footnote 21: _Dixi autem de argento vivo a metallis prolicito, quod vulgare ob nimiam frigiditatem & humiditatem nimium concoctioni est contumax, nec ab auro solum alterato coerceri potest._ Gast. Clave. in Apoll.]