A Brief History of the Compass

"In the 1830s, not much was known about the North Pole," Claudia says. "My great-great-great-grandfather believed that compasses pointed north because there was a huge meteorite up there. This is an old legend; Scheherazade told a tale about nails being pulled out of ships that ventured too close. Meteorites often contain magnetic iron, by the way.

"Early explorers quickly found out that compasses were no good when you began to get close to the magnetic pole. Captain Torvey believed that this happened for two reasons. One, their compasses were too lightweight. Two, he believed that the Great Meteorite, as he called it, moved as the ice pack shifted.

"So he invented the Bath Compass which he believed would be more accurate at close range. He assembled the compass and took a measurement once a day to see if he could learn to predict how the magnetic pole moved.

"Today we know the magnetic pole does move, probably because of fluctuations in the earth's metallic core. Captain Torvey was right about that. But just about everything else he thought was wrong."

An Access Excellence Science Mystery sponsored by Genentech, Inc.
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