At Home: A Short History of Private Life

by Bill Bryson

Consider just the first 180 feet of the structure, up to the first platform—already the height of a ten- or twelve-story building. Up to that height the legs lean steeply inward at an angle of 54 degrees. They would clearly fall over if they weren’t braced by the platform. The platform just as clearly couldn’t be up there without the four legs underneath to support it. The parts work flawlessly when brought together, but until they are brought together they cannot work at all. Eiffel’s first challenge, therefore, was to devise some way to brace four immensely tall and heavy legs, each straining to topple inward; then, at the right moment, be able to ease them into position so that all four came together at exactly the right points to support a large and very heavy platform. An incorrect alignment of as little as one-tenth of one degree would have put any leg out by a foot and a half—far more than could be corrected without taking everything down and starting all over again. Eiffel effected the delicate operation by anchoring each leg in a giant container of sand, like a foot in a large boot, which held them securely during construction. Then, when work on them was complete, the legs could be eased into position by letting sand out of the boxes in a carefully controlled manner.