make a Benefit by grinding such Crucibles to powder, to recover out of them the latent particles of Silver. And hence I might argue, that perhaps _Claveus_ was mistaken, and imagin'd that Silver to have been driven away by the Fire, that indeed lay in minute parts hid in his Crucible, in whose pores so small a quantity as he mist of so ponderous a Bodie might very well lie conceal'd. But Secondly, admitting that some parts of the Silver were driven away by the violence of the Fire, what proof is there that it was either the Salt, the Sulphur, or the Mercury of the Metal, and not rather a part of it homogeneous to what remain'd? For besides, that the Silver that was left seem'd not sensibly alter'd, which probably would have appear'd, had so much of any one of its Principles been separated from it: We finde in other Mineral Bodies of a less permanent nature than Silver, that the Fire may divide them into such minute parts, as to be able to carry them away with its self, without at all destroying their Nature. Thus we see that in the refining of Silver, the Lead that is mix'd with it (to carry away the Copper or other ignoble Mineral that embases the Silver) will, if it be let alone, in time evaporate away upon the Test; but if (as is most usual amongst those that refine great quantities of Metals together) the Lead be blown off from the Silver by Bellowes, that which would else have gone away in the Form of unheeded steams, will in great part be collected not far from the Silver, in the Form of a darkish Powder or Calx, which, because it is blown off from Silver, they call Litharge of Silver. And thus _Agricola_[3] in divers places informs us, when Copper, or the Oare of it is colliquated by the violence of the Fire with _Cadmia_, the Sparks that in great multitudes do fly upwards do, some of them, stick to the vaulted Roofs of the Furnaces, in the form of little and (for the most part) White Bubbles, which therefore the Greeks, and, in Imitation of them, our Drugsters call _Pompholix_: and others more heavy partly adhere to the sides of the Furnace, and partly (especially if the Covers be not kept upon the Pots) fall to the Ground, and by reason of their Ashy Colour as well as Weight were called by the same Greeks [Greek: spodos], which, I need not tell you, in their Language signifies Ashes. I might add, that I have not found that from Venetian Talck (I say Venetian, because I have found other kinds of that Mineral more open) from the _Lapis Ossifragus_, (which the Shops call _Ostiocolla_) from _Muscovia_ Glass, from pure and Fusible Sand, to mention now no other Concretes; those of my Acquaintance that have try'd have been able by the Fire to separate any one of the Hypostatical Principles, which you will the less scruple to believe, if you consider that Glass may be made by the bare Colliquation of the Salt and Earth remaining in the Ashes of a burnt Plant, and that yet common Glass, once made, does so far resist the