When iron ore has been turned into steel bars or wheels or gears, another kind of lifter can handle them. This one does its work with a huge electro-magnet that holds heavy weights when electricity is running through it. The operator drops the magnet onto the load of iron or steel that he wants to lift. Then he turns on the electricity which makes the magnet and the piece of metal stick together. The operator moves the load wherever it is supposed to go. Then he turns off the electricity. The magnet lets loose and is ready for another job. MACHINES FOR LUMBER, TOO Machines dug and loaded and delivered the coal that keeps your house warm. Machines helped cut the lumber that went into building your house, too. Far out in the woods, power-driven saws sliced quickly through the trunks of great trees. Caterpillar tractors hauled the logs out along rough forest trails. Perhaps the cats, using booms, lifted the logs onto extra-long trailers behind trucks and started them on the way to the sawmill. Or the cats may have snaked the logs to a river so they could float downstream to a sawmill. [Illustration] No matter how the logs reached the sawmill, they were put at last onto belts which pushed them against huge whirling saws. A whole set of saws, all whining and screaming at once, turned the thick log into boards. Other machines planed the boards to make them smooth and then cut them to exactly the right sizes. Finally lift-trucks picked up great piles of board at once, whizzed them away and hoisted them elevator-fashion into high stacks. [Illustration] [Illustration] BRAIN POWER [Illustration] The operators of most machines sit where they can see what they are doing, or where they can get signals from helpers. But there is one that does things in a new way. Its operator just watches television in his cab. He never sees the parts of his machine at work. Instead, he looks at the television screen. A television camera on the roof of the building photographs what is going on below. This is what the eye of the camera sees: One machine that gathers up pieces of scrap metal and dumps them into a squeezer; the squeezer that presses the scraps into neat bundles; a conveyor that loads the bundles into a railroad car. The operator watches the moving picture. Then he pushes levers that control the loaders and other levers that send a car on its way when it is full. The only thing he can’t do is switch on a regular TV program and watch a show while he works! [Illustration]