# Flexible poles for monument movements.

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. To demonstrate his idea, Cunningham orchestrated the lifting of a 2,600-pound load using 12 oak poles, each 1.75 inches square and 14 feet long.

"The method is astonishingly versatile," says Cunningham. "The force you can exert with these things is truly immense." A slight modification of the technique allows someone to move a heavy load in a horizontal direction. A similar principle applies when a group of people carry a load suspended from a set of poles made from bamboo or some other flexible material. The flexible poles ensure that the load's weight is fairly distributed among the bearers.

Evidence for Cunningham's scheme can be seen in ancient Egyptian art. "Loads are commonly depicted being carried on poles," he says, "and actual poles exist in museum collections." Levers, on the other hand, rarely appear in the paintings.

What surprises Cunningham is that such a simple idea has been largely lost to history. "Our modern technology is completely unaware of this force-multiplying effect," he says. "The ancient Egyptians, for example, may not have needed to use ramps in order to lift the massive building materials used in their great constructions on the Giza plateau. More importantly, there may exist new contemporary applications of the principle as well." Cunningham has applied for a patent on a structural system, based on the flexible-rod idea, that could be used in the foundations of large structures such as shopping malls to protect them from earth movements associated with earthquakes.
No portion of this article can be reproduced without the express written permission from the copyright holder.

Title Annotation: Printer friendly Cite/link Email Feedback construction of monuments in ancient Egypt Science News Apr 16, 1988 525 A sight for shadowed eyes. If it moves, catch it. Antiquities Construction equipment Poles (Building) Poles (Engineering) Structural engineering