“Not at all, the more metal the better, since it can be made light or heavy at will and so kept under control while other materials could not be made light. It is always desirable to have more than half the weight of our outfit in iron or steel on that account. Well, they landed this material on Phobos and there put it together. The different parts were insulated from each other to provide for the use of repulsion or gravitation as the case might require. “They staked off an exact square five and a half miles on each side, which was about as large a one as they could get on Phobos and at each corner they firmly anchored one end of one of the cables. At the center of the square Mars appeared directly overhead. At this point the crate was put together upside down and its load of magnets arranged inside of it also upside down. The cables 3,760 miles long were coiled in a pile each to itself and the end fastened to the corners of the crate. On Mars this outfit weighed many tons, but on Phobos it was so light that one man could lift it. Wires connected with a battery passed through the cables to regulate the weight of the concern. A small amount of repulsion raised it and carried it to the limit of the attraction of Phobos. The momentum taking it a little further, and within the dominance of that of Mars when light attraction was turned on and the crate rose or rather fell slowly toward Mars. When the cables were stretched out and the crate hung by them, it was within a few feet of the ground in some places, at others as much as one or two hundred. Its motion was from west to east at the incredible speed of 1,160 miles an hour. Its actual rate of travel is 1,681 miles per hour, but the revolution of Mars on its axis is at the rate 521 miles in the same direction, so the difference constitutes the apparent motion of the crate of Magnets. In order to get electric power from these it was only necessary to set up insulated slabs of soft iron along the route of the magnets in such position that they would pass close to them as they swept by. This was done at different places along the route, and covered altogether, distances aggregating more than three thousand miles. Of the remaining distance around the planet a part was over the sea and some over low land, where the scaffolding would be too high to pay. The electricity generated in these stationary armatures was run off to storage batteries wherever required in the equatorial regions of the planet. So, with the cable to Deimos and the big dynamo of Phobos. Mars is supplied with unlimited power at nominal cost.” “But doesn’t the plant require renewal? I should think it would rust out after awhile.”