Flexible Poles for Monument Movements

Article excerpt

Flexible poles for monumental movements

The construction of the pyramids and other monuments in ancient Egypt often required the moving and lifting of massive stone blocks. How that was done -- in a civilization that lacked simple machines such as the pulley and wheel and could not depend on domesticated animals for power -- has long been a mystery. Now John Cunningham, a professor of design and sculpture at Skidmore College in Saratoga Springs, N.Y., suggests that the Egyptians may have relied on long, slender, flexible poles to help do the work of transporting and raising heavy objects. His proposal appears in a letter published in the March 3 NATURE.

The idea is to support the load on a set of parallel, evenly spaced rods long enough to extend beyond the load's edges. Each rod would bend according to the amount of force exerted directly on it. A single person could gradually lift the load by first raising the end of one rod to a new height, say, a fraction of an inch higher, then placing a support underneath it. The entire load moves up; the rods that haven't yet been shifted straighten slightly; and the one that has been lifted is bent a little more.

Applying this operation successively to all the rod ends elevates the load by the same distance that one rod is lifted -- a divide-and-conquer strategy for coping with a massive weight. Using more rods under a given load makes it easier to lift each rod end. In contrast, rigid levers used for the same purpose would have to bear a large part of the full load at each step, making the lifting much more difficult. …