Of Metals, Gold, Silver, Brass, &c. 217 A. Pray what is the proper Nature of Metals?

B. Those Bodies are only called Metals, which are capable of being melted, or put into Fufion; of being malleated, or drawn out into thin Plates by hammering; and whofe Substance is more folid and weighty than any other Bodies.

A. How many, I pray you, of those metalick Bodies do you reckon?

B. They are in Number seven, viz. Gold, Silver, Brafs, Copper, Iron, Tin, Lead. A. Pray give me an Account of thefe Metals, and I fhall be obliged to you. B. That I gladly will, as follows:

1. Gold, is the most perfect of all Metals, or Bodies whatfoever, it is the most folid and compact of any; its Ductility is not only exceeding all others, but vaftly furprizing, as appears by thofe Instances I gave when we difcourfed of this Property of Bodies; it is fo pure, when cleanfed from Ore, that Fire will not touch, alter, or diminish its Quantity, and is reckoned on this Account the most valuable of all Metals: It is found in Mines in various Places of the World; Grains of Gold are alfo found in the Sand of many Rivers; and feveral Stones contain Particles of Gold, as Lapis Lazuli, Lapis Armenus, &c.

2. Silver,

2. Silver, is the next pure and perfect Metal to Gold; it is alfo next to it in Ductility, and Ponderofity; its Particles are most like thofe of Gold, and will therefore mix with Gold in Liquefaction; and in fhort, is in all Refpects, but two, fimilar to Gold: For, 1. Their Colour is different. 2. They require different Mediums to diffolve them; for Gold requires Aqua Regalis, and Silver Aqua Fortis, which alfo diffolves all other Metals: It is found in Mines, generally mixed with other Metals, as Gold, Copper, Lead.

3. Brass, is a Sort of Copper, mixed with Lapis Calaminaris, according to Job xxviii, 2. Brafs is molten out of the Stone; that is, by the Heat of fubterranean Fire, the Stone is fufed and tranfmuted into the Subftance of Brafs: It is dug out of Mines, or Hills, Deut. viii. 9. and is alfo factitious, or made by Art.

4. Copper, is a Metal, that abounds with Vitriol and Sulphur; the Ore is found in a Powder, or Stone, in many Mines of Europe, but especially in Sweden and Den

mark.

5. Iron, is a very porous Metal, compounded of a vitriolic Salt, Sulphur, and Earth, il digefted together; it is much harder, lefs ductile, and more impure, than the foregoing Metals. Iron Ore is found in many Mines of Europe, in Form of a

Stone,

Of Tin, Lead, Stones.

Stone, or Marcaffite. Steel is only Iron rified, and indurated, or hardened.

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6. Tin, is a malleable Subftance, fulphureous, and easily put into Fufion, or melted; it is of a Silver Colour, but more porous and lighter than Silver. It was by Pliny called a white Lead. It is found in mány Mines, especially in our own Island.

7. Lead, is a Metal-filled with Sulphur, or a bituminous Earth, which makes it more fupple and pliant than any other; it is alfo found to contain fome Mercury; it is the most grofs and impure of all Metals, and therefore the eafieft to be diffolved: It is found in many Countries, fixed to diverse Sorts of Stones and Earths, containing fome Silver, and fome both Gold and Silver. And these are the principal Accounts I meet with concerning the Nature and Production of Metals.

A. Well, Sir, I heartily return you thanks; and, if you are not tired with talking fo long, I fhould next be glad to hear you on the Subject of the fixth general Head, viz. Stones.

B. No, Sir, I am never tired on the Subjects of Mathematicks and Philosophy; and therefore I will go on to enumerate fome of the principal Stones, and hint to you the particular Properties of each of

them.

1. Marble,

1. Marble, is a curious Subftance, arifing from an earthy Juice, well purged, concocted, and digefted in the great Laboratory of the Earth; a Body very compact and hard, and may be calcined to Powder, but cannot be put into Fufion.

2. Alabastre, is a Kind of Marble, but more foft and friable, and is cumbustible like Lime; but as ponderous and polite as Marble it felf.

3. Porphyry, is another Species of Marble, various coloured, fomewhat lighter than Marble, yet very hard.

4. Flint, is an exceeding hard Substance, generated from the pellucid Particles of Sand compacted together, and indurated; and may be put into Fufion, whence Glafs is made.

5. Chryftal, is a very pellucid transparent Gem; the moft pure is found in the Tops of Rocks and Mountains, and dug out of the Bowels of the Earth alfo; it is not coloured, is fofter than other Gems, and therefore shineth not much; it confifteth of an aqueous Subftance, and is therefore eafily liquefied and converted into Glafs, faith Cardan.

6. Adamant, or Diamond, is in Colour and Figure much like Chrystal, generated in the fame Manner, but its Hardnefs far exceeds that of all other Bodies; for it will

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Of various Kinds of Stones and Gems. 221

cut and penetrate the Texture of any of them; it has an electrick Quality, in attracting Straws, Feathers, &c. being warmed by Attrition.

7. Beryll, is a Stone, much of the Nature of a Chryftal, of a faint green Colour; found at the Roots of Mount Taurus, in the River Euphrates, and in the Indies.

8. Smaragdus, an Emerald of a lovely Green, and of fo ftrong a Luftre, that it shineth in the Light of the Sun or Candles; it is very transparent, and said to tinge the Air with its Greennefs.

9. Carbuncle, is a precious Stone of a tranfcendent Luftre; being of a glowing fiery Colour, like a burning Coal, as the Name importeth.

10. Ruby, fo named of its noble red Colour, is the most valuable of all precious Stones next the Diamond; it is faid to be first white, and to grow red gradually from a fanguine Juice, of which it is nourished and generated from at first.

11. Hyacinth, or Jacinth, is a Species of the Carbuncle, of a red-lead Colour; ic having its Name from a Flower of the fame Colour.

12. Amethyst, this is near the Nature of an Hyacinth, is of a purple Colour, arifing as it were from a Mixture of red and blue; they are very hard, and the harder the better.

13. Sapphir,