Peter Terreros, the first Count of Regla, became one of the rich men of the last century in consequence of a lucky mining adventure. In olden times the water in the Real del Monte mines had been lifted out of the mouth of the Santa Brigeda and other shafts in bulls' hides carried up on a windlass. When near the surface, this simple method of getting the water out of a mine has great advantages on account of its cheapness, and is now extensively employed in Mexican mines. But after a certain depth had been reached, the head of water could no longer be kept down by this process, and, in consequence, the Real del Monte was abandoned about the beginning of the last century, and became a complete ruin; for no wreck is more complete than that which water causes when it once gets possession of a mine, and mingles into one mass floating timbers, loosened earth, rubbish, and soft and fallen rock. By the mining laws of Mexico, the title to a mine is lost by abandoning and ceasing to work it. It becomes a waif open to the enterprise of any one who may "re-denounce" it. The title to the soil in Mexico, as in California, carries no title to the gold and silver mineral that may be contained in the land. The precious metals are not only regarded in law as treasure-trove, but they carry with them to the lucky discoverer the right to enter upon another person's land, and to appropriate so much of the land as is necessary to avail himself of his prize. Colonel Fremont's Mariposa claim, and all other California land claims, are subject to this legal condition. PETER TERREROS. Peter Terreros, then a man of limited means, conceived the idea of draining this abandoned mine by means of a tunnel or adit (_socabon_) through the rock, one mile and a quarter in length, from the level of the stream till it should strike the Santa Brigeda shaft. Upon this enterprise he toiled with varied success from 1750 until 1762, when he completed his undertaking, and also struck a _bonanza_, which continued for twelve years to yield an amount of silver which in our day appears to be fabulous. The veins which he struck from time to time, as he advanced with his _socabon_, furnished means to keep alive his enterprise. When he reached the main shaft, he had a ruin to clear out and rebuild, which was a more costly undertaking than the building of a king's palace. Yet his _bonanza_ not only furnished all the means for a system of lavish expenditure upon the mines and refining-works, but from his surplus profits he laid out half a million annually in the purchase of plantations, or six millions of dollars in the twelve years. This is equal to about 500,000 pounds' weight of silver. Besides doing this, he loaned to the king a million of dollars, which has never been paid, and built and equipped two ships of the line, and presented them to his sovereign.