"Castro's mine is situated on the southern ridge, and was the first mine worked to any extent. There the veins are very large; in fact, from the manner in which a number of horizontal veins are seen falling into the perpendicular or master vein, the great body of the mountain would appear to consist of lodes. This mass of ore is in general rich. It has been worked open to the surface, somewhat like a quarry, so that it is not difficult to calculate in cubic feet the quantity that has been excavated. The mine is supposed to have yielded in the course of the last six years gold to the value of 40,000_l._, and by measuring the excavations it would appear that this amounts to, on an average, one ounce of fine gold to every ten or twelve quintals of ore. In 1821 the existence of silver was only imagined. In 1823 it was fully ascertained. Ever since 1824 it has constituted a small but constant portion of the produce of Quebrada-honda, and in 1827 it was decidedly evinced in Coralillo. The discovery of gold in Coralillo led them to work in Quebrada-honda, where they found both gold and silver, and the discovery of silver in Quebrada-honda, by strengthening the expectation of it in Coralillo, led in its turn to the discovery of silver there. In Quebrada-honda they only work on the ground in the immediate vicinity of the stream, and that in the most imperfect manner; but great light has been thrown on the value of the ores on this spot and in the district generally by the progress made in working what is called Padre Arias Mine, which takes its name from an ecclesiastic who first worked it. This mine is situated in low ground near the verge of the stream, and was at first only worked for gold. There were soon, however, indications of silver, which increased progressively in sinking, till at the depth of only 10 yards the influx of water exceeded the means of draining, and the works under water-level were necessarily abandoned, at a time when ores were yielding upwards of 200 oz. of silver to the ton, a striking proof of the tendency of silver ore to improve in this district as the depth increases. "Mr. Richard Trevithick, that eminent Cornish miner and engineer, so well known for his inventions, and particularly for the high-pressure steam-engine and the drainage of the Pasco Mines in Peru, when unfortunately civil war burst out in Peru, and the Royalists, considering those engines as the main instrument for supplying money to the Independents, rendered them useless by destroying or carrying off some of the most important pieces. "Mr. Trevithick having heard favourable reports of the mining district we are now describing, soon after repaired thither, and was so fully impressed with its value and importance that he made an extensive contract for different properties, and resided in the country for four years.