until we at last reached a vacant shaft, through which we were drawn up and landed in the prison-house, from whence we walked to the station-house, where we were dressed in our own clothes again. REFINING SILVER. When my underground wanderings were ended, and dinner eaten, it was too late in the day to visit the refining works; but on the next morning, bright and early, I was in the saddle, on my way to visit the different establishments connected with this mine. First, upon the river, at the mouth of the adit, was a stamping-mill, where gangs of stamps were playing in troughs, and reducing the hard ore to a coarse powder. A little way farther down the stream the ore was ground, and then, in blast ovens or furnaces, was heated until all the baser metals in the ore became charged with oxygen to such a degree that they would not unite with quicksilver. The ore was then carried and placed in the bottom of large casks, and water and quicksilver were added, and then they were set rolling by machinery for several days, until the silver had formed an amalgam with the mercury, while the baser metals in the ore were disengaged from the silver. The whole mass being now poured out into troughs, the scoria was washed off from the amalgam, which was gathered and put into a stout leathern bag with a cloth bottom, and the unabsorbed mercury drained out. The amalgam, resembling lead in appearance, being now cut up into cakes, and placed under an immense retort, fire was applied; the mercury, in form of vapor, was driven through a hole in the bottom of the platform into water, where it was condensed, while the silver remained pure in the retort. This is called the barrel process, and is used for certain kinds of ore. I had come self-introduced to the Real del Monte, but that had not prevented my receiving the accustomed hospitality of the establishment. A groom and two of their best horses were at my service during my stay. As the weather was fine, and the roads of the first class of English carriage-ways, I heartily enjoyed the ride down the mountain gorge until it opened upon the broad plain where the second refining establishment, that of Vincente, is situated. Except that the iron floors of their blast ovens were made to revolve while in a state of red heat, all was substantially the same as at the last place. Following the meanderings of the stream, I had been gradually descending from the sharp air of early spring to the more appropriate temperature of the tropics, as I had occasion to notice in looking into the fine garden of the English director, which exhibited both the fertilizing effects of irrigation upon English flowers, and the advantages of tropical heat upon native varieties. [72] A very rich portion of a vein is called a _bonanza_. [73] Mr. Thomas Auld, the director of the company, furnished me very accurate data in relation to affairs, but these are with my other losses at New Orleans.