"STORIES FROM THE KANSAS STATE CAPITOL: THE FOUCAULT PENDULUM"

A Moment in Time

Kansas Historical Society

April 2001, Part 5 of 10

A monthly series from the Kansas Historical Society

The Kansas State Capitol was once the home of the world's "tallest pendulum." On November 15, 1945, Dr. George W. Davis of Ottawa hung a 105-pound lead weight which was attached to a 163-foot piece of number 14 wire. This was suspended to the ground floor from the inner dome of the Kansas Capitol. At 9:00 a.m. each morning, L. D. Robinson , custodian, would start the pendulum swinging back and forth in a 14-foot swath across the floor. Later in the day, the pendulum would be swinging in a path well off the original course. What did this mean?

In 1851, physicist Jean Foucault, came up with the idea to prove a long-known belief that the earth rotates on its axis. Foucault knew that a pendulum which is supported so as to be free to swing in any plane will tend, because of its inertia, to keep on swinging in the same direction. Therefore, if the earth were stationary, an undisturbed pendulum would continue to swing in the same direction until friction finally stopped it. But if the earth rotates, a swinging pendulum would appear to change direction according to the earth's rotation.

Numerous changes were made to perfect the performance of the pendulum. Davis used plow discs and filled them with melted lead. Robinson was quoted as saying "We tried piano wire on the first one and it wouldn't hold the weight. I had to send three or four workmen up to the dome with some heavier wire. We used a 105-pound weight first. Now the pendulum weighs 205 pounds and works all right." The swivel from which it hung had to be oiled to minimize friction. Measurements were made and proved that the pendulum had not varied from its orbit one-hundredth of an inch.

There were at least eight other Davis-placed, Faucault pendulums throughout the United States including Yale, Princeton and the University of Chicago. Others were at the Museum of Science in Washington D.C., Griffith Park Museum in Los Angeles and Berry school in Berry, Georgia plus another in Kansas at the Franklin County Courthouse. Faucault's original pendulum was displayed in the Pantheon in Paris.

Davis said: "It was my ambition to put one in the national capitol in Washington. I went there one time with my wife, Dr. Josephine Davis, who is 13 years my junior. We looked at the dome and observed where the pendulum would swing. 'Father, you can't do it,' my wife said. 'Your chart will cover the Great Seal of the United States.' I saw that she was right and decided to give it up."

While the pendulum entertained and stimulated thought-provoking onlookers, it apparently became somewhat burdensome to Robinson who had to start it each morning and patrol it to see nobody interfered with its natural motion. A railing was eventually built around it for protection. A glass enclosure was suggested by Davis but was never constructed.

Robinson contended that "People in the statehouse are in the mood to see dignity, not to see a scientific experiment that looks like an amusement piece. I think it makes the statehouse look like some kind of a grown-up county courthouse." When Robinson was once asked if it could tell time, he replied, "Yes, and no. But who cares? You can't carry a thing like that around in your pocket."

To learn more stories about the Kansas State Capitol, join a free guided tour at 9:00 a.m., 10:00 a.m., 11:00 a.m., 1:00 p.m., 2:00 p.m. or 3:00 p.m. Monday - Friday. The Capitol is located at 300 W. Tenth Topeka KS 66612; 785-296-3966; www.kshs.org. To reach the Capitol in downtown Topeka take exit 362B I-70 and follow the signs. During the legislative session, January through May, parking is limited.

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© Kansas Historical Society 2001