others, seldom requiring more than eight days for the completion of the process.
The vein of the Descubridora, as well as that upon which the German Mine of San Atenogenes is situated, contain a large proportion of bleierze, or silver mixed with lead. In all, there is a considerable mixture of zinc (blende, estoraque), and native antimony (spiesglaserz), which are very troublesome, as they must be separated by the pepenadores (ore-dressers), before the ores are stamped, both being unfavourable to the action of the quicksilver. Besides these, there is much acaporosa (carbonate of iron).
In order to get rid of a part of these extraneous substances, it becomes necessary to roast the ores after they are dressed; the process lasts about three days, and is continued until fourteen cargas of ore are reduced to ten. The expence is from five to six dollars per monton.
The ores called Colorados may be reckoned also amongst the peculiarities of Angangeo. They are generally found in the levels nearest the surface, and are, in fact, metals in a state of decomposition, strongly impregnated with a reddish oxyd of iron. They are usually rich, containing as much as sixteen, eighteen, and even twenty marcs of silver in the monton (of thirty hundred weight). When amalgamated, they require more time, and more quicksilver, than the other ores of this district, but no magistral. In
