The _yucca_ (cassava-root) is a plant of fifteen or twenty feet in height. It is difficult to distinguish this plant from the _mandioc_, which is called "wild yucca;" and this, "sweet yucca." This may be eaten raw; but the other is poisonous until subjected to heat in cooking, and then is perfectly wholesome. The yucca answers the same purpose in Peru that the mandioc does in Brazil. It is the general substitute for bread, and, roasted or boiled, is very pleasant to the taste. The Indians also make from it an intoxicating drink. Each plant will give from twenty to twenty-five pounds of the eatable root, which grows in clusters like the potato, and some tubers of which are as long and thick as a man's arm. CHAPTER XII. HERNDON'S EXPEDITION CONTINUED. On the 4th of July, the travellers arrived at the great mining station of Cerro Pasco. The weather was so cold, that the lieutenant, not being quite well, sat by the fire all day, trying to keep himself warm. The town is a most curious-looking place, entirely honey-combed, and having the mouths of mines, some of them two or three yards in diameter, gaping everywhere. From the top of a hill, the best view is obtained of the whole. Vast pits, called Tajos, surround this hill, from which many millions of silver have been taken; and the miners are still burrowing, like so many rabbits, in their bottoms and sides. The hill is penetrated in every direction; and it would not be surprising if it should cave in, any day, and bury many in its ruins. The falling-in of mines is of frequent occurrence: one caved in, some years ago, and buried three hundred persons. An English company undertook mining here in 1825, and failed. Vast sums have been spent in constructing tunnels, and employing steam machinery to drain the mines; and the parties still persevere, encouraged by discovering, that, the lower they penetrate, the richer are the ores. The yield of these mines is about two million dollars' worth a year, which is equal to the yield of all the other mines of Peru together. The lieutenant found the leading people here, as well as at Tarma, enthusiastic on the subject of opening the Amazon to foreign commerce. It will be a great day for them, they say, when the Americans get near them with a steamer.