ounces of the above-mentioned earth, yield an ounce and a half only of silver." It is not, however, possible to reconcile so small a gain with the annual produce of four millions two. hundred and fifty thousand forty-three piastres, resulting from an average estimate of the first ninety-three years during which the mines of Potosi were wrought. This was the amount of the coinage; but the extraction of silver was still greater, it having been annually carried to five thousand quintals.
This fecundity was calculated to draw the public attention exclusively to the above mineral territory, and to throw a discredit on all the other mines of Peru, which were not capable of yielding collectively more than a thousand quintals of silver. Of this produce, Oruro supplied seven hundred quintals; Castro Virreyna, two hundred; and the remainder belonged to the excavated mountains. At Potosi, however, the encouragement was equal to the abundance of the acquired riches. Thirteen thousand Indians were placed on a permanent establishment, and constantly engaged in the different tasks assigned to them; at the same time that five thousand quintals of mercury were annually consumed, in separating the metal from the ores. This extraordinary consumption was owing to the ignorant method of assigning to each quintal of silver, an equal quantity of that necessary ingredient.
It would appear that the epoch is not very distant, when the clouds which have hitherto obscured the Peruvian horizon, in this doctmastic part, as well as in all the other branches of mineralogy, will be dispersed. The expedition which has, with this view, been confided by His Catholic Majesty to the
