"The man entered the mine, carrying a bar of iron and a rawhide bag. In a little while I heard the blows of the bar, and in the course of half an hour he returned with about twenty pounds of ore in the bag. Then the man and the woman pounded the ore upon flat stones, and reduced it to a coarse dust, which was placed in an earthen pot over a fire. The fire was fed and tended by the boy, while the man and woman looked on; they had performed their share of the toil, and were willing to give the youth a chance. "A smaller pot was brought, in which the ore was placed after half an hour's roasting in the large one. This pot was filled with the dust, deposited on the bed of coals, and covered with a loosely fitting lid. The wood was piled over it and the fire burned fiercely. The whole mass became red-hot, and the fumes of sulphur filled the air as they rose from the smelting-pot. "The fire was allowed to burn down, and when it was reduced to ashes and embers the pot was lifted out, and its contents were poured on the ground. There was a confused mass of slag and ashes, and in a few moments the man who had taken the ore from the mine pushed from the slag a button of silver weighing something more than an ounce. It was thrown into water to cool, and when in a condition to be handled it was passed over to me. I gave the man a dollar, together with some smaller coins to the woman and boy, and then walked away with my trophy." Frank and Fred were much interested in this account of the silver mines of Bolivia, and the primitive ways of working them. As soon as the conversation was over they wrote it out, as nearly as they remembered it, in order that none of the information should be lost. Then followed a technical account of the character of the ores, but it might be tedious to the general reader, and we will omit it. Their informant further told the youths that a good many of the natives support themselves by melting the ores in the manner just described, and selling the buttons for what they will bring. The silver thus obtained is not chemically pure, but is good enough for purposes of sale. Fred asked if accidents were common in the mines at Potosi. [Illustration: GALLERIES IN A SILVER MINE.] "Of course they have accidents there," was the reply, "but probably no more on the average than in mines in other parts of the world. Most of them are due to carelessness, either in failing to support the roof properly after the ore is taken out, or not taking proper hold of the ladders while ascending or descending. Sometimes the roof of a mine falls in, but there is generally sufficient warning to allow the men to escape. Rocks occasionally become dislodged and fall upon the workmen; I was one day walking in a mine when a stone weighing at least a ton fell behind me, right in my tracks. If I had been three or four seconds later it would have crushed me. [Illustration: CAVING IN.]