gold remained; to effect the separation of this by
nitrio-hydrochloric acid was more expensive than the value of the
gold; it was therefore left in utensils, or circulated in coin,
valueless. The copper, too, of the native silver was no use
whatever. But the 1/1000th part of gold, being about one and a half
per cent. of the value of the silver, now covers the cost of
refining, and affords an adequate profit to the refiner; so that he
effects the separation of the copper, and returns to his employer
the whole amount of the pure silver, as well as the copper, without
demanding any payment: he is amply remunerated by that minute
portion of gold. The new process of refining is a most beautiful
chemical operation: the granulated metal is boiled in concentrated
sulphuric acid, which dissolves both the silver and the copper,
leaving the gold nearly pure, in the form of a black powder. The
solution is then placed in a leaden vessel containing metallic
copper; this is gradually dissolved, and the silver precipitated in
a pure metallic state. The sulphate of copper thus formed is also a
valuable product, being employed in the manufacture of green and
blue pigments.

Other immediate results of the economical production of sulphuric
acid, are the general employment of phosphorus matches, and of
stearine candles, that beautiful substitute for tallow and wax.
Twenty-five years ago, the present prices and extensive applications
of sulphuric and muriatic acids, of soda, phosphorus, &c., would
have been considered utterly impossible. Who is able to foresee what
new and unthought-of chemical productions, ministering to the
service and comforts of mankind, the next twenty-five years may
produce?