III.: Fine silver and fine gold, of equal goodness every where.

25. Silver and gold, when pure and unmixed with base metals, are called fine, or fine silver, and fine gold. And these, called the precious and noble metals, when thus pure, have every where the same characteristics, and in all respects the same qualities, so far as hath hitherto been discovered; that is, an ounce of any fine silver, is exactly of the same intrinsic worth or value, with an ounce of any other fine silver: And the same of fine gold, with respect to fine gold.

But these precious metals are seldom found pure, till they are made so by art for particular purposes; and when they are not pure, the metal commixed with them is called alloy. This alloy is reckoned of no value; that is, if to an ounce of fine silver be superadded, suppose, an ounce of copper; this addition of copper, though it increases the mass to double the quantity, yet gives that mass no additional value: So that one ounce of fine silver, is of as great value as the two ounces of this mixed mass. And the reason of it is, because these metals cannot be again separated, either without a total loss of the copper, or without more cost than profit. In like manner, not only copper, but silver also, is an alloy to gold; and when they are commixed together, the silver is reckoned of no value, unless it be in such proportion to the gold, as to make it worth the refiner’s while to separate them.

Silver and gold, when alloyed, are said to be of such a fineness, according to the proportion there is of fine silver or fine gold, to the whole mass. Thus, a mass of silver, containing eleven parts of pure or fine silver, and one part of alloy, is said to be 11/12 fine; or with us in England, cleven ounces fine; because our pound for weighing gold and silver, is subdivided into twelve ounces.