These mantadas are purchased by a class of men called bolicheros, or owners of boliches. This boliche is, to the common grinding-mills on the mine-estates or haciendas, what the hand-mill of the Israelites was to the modern corn-mills moved by machinery: it is a kind of rocking-stone, placed on the concave surface of a larger stone well accommodated underneath. Metal, in comparatively small quantities, is ground between these two stones by a man who, with the help of a long pole, balances himself on the upper roundish and heavy stone, which by the weight and motion of his own body he keeps rocking incessantly. The metal, or ore, thus ground, is the very richest; poor or ordinary ore could not pay on this small scale: but the ore bought of the labouring miners usually enriches the bolichero, who, tempted by the prospects of a ready fortune, does not hesitate to encourage the thieving practices complained of in the departmental report of our friend the prefect of Junin, himself a native of Cerro Pasco. The town of Cerro Pasco—of which the very “adobes,” or unburnt bricks, partly used in some of the houses, contain silver—is itself so burrowed under, that one is really in no small danger of inadvertently, and especially at night, falling into old mines, or rather pits,—sometimes superficial, sometimes deep and fathomless, and half filled with water. The mines are irregularly wrought under ground; and the experienced hands burrow like rabbits through holes not commonly known, and so come at rich metals by stealth, to be immediately exchanged for dollars at the bolicheros. The best way to prevent such plunder would be to prohibit boliches. While this species of robbery goes on, Cerro Pasco, though removed from the sphere of the earthquakes that infest the coast, is in risk of being swallowed up by the falling-in of the arches of the mines, supported on pillars frequently consisting of rich ore. The thieves pilfer from these pillars, and so weaken the supports of the whole underground fabric, that now and then entire arches fall in, sometimes producing a sacrifice of lives or other disastrous consequences.