years on the surface, is now thought
capable of yielding a second crop; and when I was at Lima, they were
actually turning it up, and milling it over again with great success.
This is a proof that these minerals generate in the earth like all
other inanimate things;[3] and it likewise appears, from all the
accounts of the Spaniards, that gold, silver, and other metals are
continually growing and forming in the earth. This opinion is verified
by experience in the mountain of Potosi, where several mines had
fallen in, burying the workmen and their tools; and these being
again opened up after some years, many boxes and pieces of wood were
discovered, having veins of silver actually running through them.[4]

[Footnote 3: It is merely a proof that the ore had been formerly very
imperfectly managed, and still contained enough of silver to pay for
extraction with profit, by more expert methods.--E.]

[Footnote 4: This proves only change of place, by solution,
infiltration, and deposition not growth, increase, or new
production.--E.]

All these mines become the property of their first discoverer, who
immediately presents a petition to the magistrates, desiring to have
such a piece of ground for his own. This is accordingly granted, and
a spot of ground eighty Spanish yards in length by forty in breadth[5]
is measured out and appropriated to the discoverer, who chuses what
spot he pleases within these bounds, and does with it as he thinks
fit. The exact same quantity is then measured off as belonging to the
king, and is sold to the best bidder, there being always many who are
willing to purchase, what may turn out an inestimable treasure. After
this, if any person may incline to work a part of this mine on his own
account, he bargains with the proprietor for a particular vein. All
that is dug out by any one is his own, subject however to payment of
the royal duties; being one-twentieth part for gold, and a fifth for
silver; and some proprietors find a good account in letting out their
grounds and mills to others.

[Footnote 5: In Harris this is said to be _about 1200 feet in length,
and 100 in breadth_, which is obviously absurd; as the one measure
gives the Spanish yard at 15 English feet, and the latter at 2-1/2
feet. Both measures are probably erroneous; but there are no data for
their correction.--E.]

There are gold-mines just beyond the town of Copaipo, and in all the
country around, which have attracted many purchas