It had long been deemed of the utmost importance to devise some easier mode of locomotion; but it was not till 1833 that the circumstance of two water-wheels having been thrown out of work by the opening of the deep Georg Adit in the Hartz mines suggested the idea of employing the pump-rods for aiding the ascent of the miners. The trial was first made with a portion of one hundred fathoms. This was divided into twenty-two portions; and on each portion iron steps were fixed, at intervals of four feet, while hand-holds were fixed at convenient distances. A reciprocating motion of four feet was given to each rod, and the miners stepped to and fro from a bracket or ledge on one rod to the parallel one on the other. As one rod is always descending while the other is ascending, and _vice versâ_, it is easy to understand how this alternate stepping on to the little platforms must lead to the ascent or descent of the miner. At the division between each two of the twenty-two portions, there is a larger platform on which he may rest awhile; and nothing is lost by his rest, for the reciprocal motion goes on, and is ready again for his use when he is ready for it. This first machine surpassed expectation. Short as the length of ascent was, many invalids of the district were now able to resume their underground labours, as the fatigue of mounting or descending was reduced, by the alternate action of the machinery, to a mere easy lateral motion. The advantages of this new method in saving both time and power were so obvious that it was soon imitated in the other deep metalliferous veins of the Hartz; and at present power-ladders or _man-engines_ of an improved construction, such as the substitution of a single rod for the double apparatus above described, are in very general use over the Continent, whence they have passed in a modified form into Cornwall, where they are worked by steam. In Fowey Consols Mine the machine extends to a depth of 1,680 feet. The rod is eight inches square, with twelve-inch platforms at intervals of twelve feet; and there are stationary platforms equidistant at the side of the shaft. When a miner is about to descend the steps on a movable platform, the rod descends and carries him down twelve feet; he steps upon a fixed platform while the rod rises again; he then steps upon another movable platform, and descends another twelve feet, and so on to the bottom. In ascending, there is simply a reversed process. It is a very interesting sight to witness the ascent or descent of bodies of miners at certain hours of the day and night. You see them passing each other in the shafts, in a kind of zig-zag course, of as great regularity as any zig-zag will permit. As one miner steps off the rod platform to one fixed platform, another steps on to it from another fixed platform on the other side. Thus there are two streams of miners moving in opposite directions along the same rod at the same time, and this curious spectacle is rendered