The riches of the place consist chiefly in the mines, which we supposed to lie far up the country, though we could never learn where, or at what distance; for the situation is concealed as much as possible, and troops are continually employed in guarding the roads that lead to them: it is almost impossible for any man to get a sight of them, except those who are employed there; and, indeed, the strongest curiosity would scarcely induce any man to attempt it, for whoever is found upon the road to them, if he cannot give undeniable evidence of his having business there, is immediately hanged up upon the next tree. Much gold is certainly brought from these mines, but at an expense of life that must strike every man, to whom custom has not made it familiar, with horror. No less than forty thousand negroes are annually imported on the king’s account, to dig the mines; and we were credibly informed, that the last year but one before we arrived here this number fell so short, probably from some epidemic disease that twenty thousand more were draughted from the town of Rio. Precious stones are also found here in such plenty, that a certain quantity only is allowed to be collected in a year; to collect this quantity, a number of people are sent into the country where they are found, and when it is got together, which sometimes happens in a month, sometimes in less, and sometimes in more, they return; and after that, whoever is found in these precious districts, on any pretence, before the next year, is immediately put to death. The jewels found here are diamonds, topazes of several kinds, and amethysts. We did not see any of the diamonds, but were informed that the Viceroy had a large quantity by him, which he would sell on the King of Portugal’s account, but not at a less price than they are sold for in Europe. Mr. Banks bought a few topazes and amethysts as specimens: of the topazes there are three sorts, of very different value, which are distinguished here by the names of Pinga d’agua qualidade primeiro, Pinga d’agua qualidade secundo, and Chrystallos armerillos: they are sold, large and small, good and bad together, by octavos, or the eighth part of an ounce; the best at 4s. 9d. All dealing, however, in these stones is prohibited to the subject under the severest penalties: there were jewellers here formerly, who purchased and worked them on their own account; but about fourteen months before our arrival, orders came from the court of Portugal, that no more stones should be wrought here, except on the King’s account: the jewellers were ordered to bring all their tools to the Viceroy, and left without any means of subsistence. The persons employed here to work stones for the King are slaves.