Point I

In the first place all Fossiles, by the mediation of this Subject, may be perfectly examined, what Metals they properly contain, how many, and how much of each.

For the verifying and demonstrating this first point, I will begin to shew, that Minerals may be most commodiously proved by the Mediation of the Salt of the Earth, and in what manner this is to be done. First, The Mineral is to be finely powdered, whether it be Gold, Silver, Copper, or Lead. To a hundred weight of this, add three or four hundred weight of Calcined or fixed Nitre, [Note, That the small Say weight is here meant] mix all very well together, put the mixture into a very strong Pot, which is to be shut with its Cover, set it upon a small foot in such a melting Furnace, as is described in the fourth part of my Furnaces, kindle the fire by degrees, and let the minera, or Ore flow well with its liquor in the Pot, like water, then pour it out into a Vessel fit for this purpose, suffer it to cool, then take out the Regulus; if it be ☉, ☽, ♀, or ♄, weigh it in a Probatory Balance, and you shall find how much ☉, ☽, ♀, or ♄, there is in that Ore. NB. That Iron and Tin cannot be proved in this manner, for ♂ is not fusible in such a fire, and ♃ is reduced into Scoria by Combustion, by reason of the Salt. NB. That if the Regulus of ☉ or ☽ come not pure, or contain any ♀ or ♄, suffer it to run upon a Test or Cupel, with a little ♄, till it sparkle and shine, and you shall have the Metal fine, which is a proof that may securely be trusted, and according to that a Computation may be made, without any fear of fraud or Sophistication; the Regulus of Copper or Lead, need no other trial, but are judged good. NB. That if the Ore be stubborn, and yields no Regulus in the first melting, let the Pot be again set into the Furnace, (if it be yet whole, putting to the Ore, giving no Regulus, a piece or two of Iron) being covered, least the Coals fall into it, suffer it to flow, then the iron entereth into that untameable Sulphur, existing in the Ore, and hindering it from passing into Regulus, and suffereth the Gold, Silver, Copper, or Lead, contained in that Mineral, to fall down, which is to be poured out into a fit vessel, and the Regulus will settle to the bottom, which being cold is to be separated from the Scoria; but if you will prove whether or no the Gold containeth any Silver, or the Silver any Gold or Copper, or the Lead any Silver or Gold, then suffer the Regulus to flow upon a Cupel, till it sparkle with a Splendour, and afterwards make separation by Aqua fortis, and you shall find how much of every Metal is permixed with the other. There is no need to describe this separation at large, because it is every where known, and now very perspicuously taught by Lazarus Erker, so that it needs no repetition: I have here shewed, and proved, that by the Mediation of Nitre, Minerals may easily and speedily be examined. Therefore, this first Point being now proved and verified, I give thanks to God, who I trust, will further assist me.