Page:Philosophical Transactions - Volume 001.djvu/354

 characters, that distinguish one sort from another?

64. What proportion of Metal it affords? (As in our Iron-mines 'tis observed, that about three Tuns of Iron-stone will afford one Tun of Metal: And I have had Lead-Ore, which an Ingenious man, to whom I recommended such Tryals, affirm'd to me to afford three parts in four of good Lead.)

65. Whether the Ore be pure in its kind from other Metals, and, if not, of what Metals it participates; and in what proportion? Which is especially to be inquired into, in case the Mine be of a base metal, that holds a noble metal: (As I have known it observ'd, that Lead-Ore, that is poor in its own metal, affords more Silver, than other; and I remember, that the Ore lately mention'd, being rich in Lead, scarce afforded us upon the Cuppel, an Atome of Silver. And Matthesius informs us, that a little Gold is not unfrequently found in Iron-Ore. And I have by me some Gold, that never endur'd the Fire, taken out of a Lump of Tin-Ore.)

About the sixth Title.

66. What are the mechanik and prævious Operations, as Beating, Grinding, Washing, &c. that are used to separate the Ore from the Heterogeneous Bodies, and prepare it for the Fire? Or whether the Ore requires no such preparation? (as It often happens in Lead, and sometimes in Iron, &c.)

67. Whether Mercury be made use off, to extract the nobler from the baser metals? (as is their practice in Peru, and other parts of the West-Indies.)

68. Whether the leaving the Ore expos'd to the open Air and Rain for a good while, be used as a Præparative? (as I have seen done in Iron-stone.)

69. Whether the Burning and Beating of the Ore be used to prepare it for the Furnace? (as is practised in Iron, and almost always in Copper:) And, in case they use it more than once, how often they do it; (for, Copper-Ore is in some places washed 8. or 10. times, and in others, 12. or 14.) and with what circumstances; as, how long the Ignition lasts at a time, whether the Ore be suffer'd to cool of it self, or be quench'd? whether it be washed betwixt each Ignition?

70. What Flux-powders, and other ways they have to try Rh