Imagine an enormous furnace holding between two and three hundred tons of metal and burning with such a terrific heat that by contrast boiling water would seem cool and comfortable. Suddenly, while you stand looking at it, but a long way off, a door flies open and the most beautiful cascade--only it is not a waterfall, but a _copper_ fall--pours out. It looks like red, red gold, rich and wonderful, with little flames of red and blue dancing over it. It might almost be one of the fire-breathing dragons of the old story-books; and if it should get loose, it would devour whomever it touched far quicker than any dragon. It hardly seems as if any one could manage such a monster; but it looks easy, after you have seen it done. An enormous horizontal wheel revolves slowly. On its edge are moulds shaped like bricks, but much larger. On the hub of the wheel a workman sits to direct the filling of these. A set of them is filled, and moves on, and others take their place. When they are partly cooled, another workman, at the farther side of the wheel, pries them out of the mould and drops them into water. Then by the aid of the fingers of a machine and those of men, they are loaded upon cars. In copper there is often some gold and silver. The precious metals do not make the copper any better, and if they can be separated from it, they are well worth the trouble. This is done by electricity. It is so successful that the metallurgists are hoping soon to take a long step ahead and by means of electricity to produce refined copper directly from the ore. Indeed, this has been done already in the laboratories, but before the managers of mines can employ the method, a way of making it less expensive must be discovered. No mine that wastes anything is as well managed as it might be; and superintendents are constantly on the watch for cheaper methods and for ways to make the refuse matter of use. Even the scoria, or slag from the furnaces, has been found to be good for something, and now it is made into a coarse sort of brick that for certain rough uses is of value. By the way, the shaft of a copper mine, the Red Jacket, has shown itself of use in a manner that no one expected, namely, it helps to prove that the earth turns around. This shaft is the deepest mining shaft in the world, and when you get into the cage, you go down a full mile toward the center of the earth. If you drop any article into the shaft, it always strikes the east side before reaching the bottom. The only way to explain this is that the earth turns toward the east.