Bank’s pendulum, only one in state, shows Earth’s rotation
By: ED KEMMICK | April 15, 2016
Jim Bennett stands above the base of the Foucault’s pendulum that he installed in 1978 in First Citizens Bank, now Western Security Bank, in downtown Billings.
How many people know that the only Foucault’s pendulum in Montana is located in downtown Billings, in the Western Security Bank building?
For that matter, how many people know what a Foucault’s pendulum is?
Basically, it is a simple device that demonstrates that the Earth rotates on its axis. French physicist Leon Foucault (“foo-koh”) debuted his pendulum in 1851 at the Paris Observatory, suspending a 62-pound cannon ball by a 200-foot-long piano wire from the dome of the building. A few weeks later he installed his most famous pendulum in the Pantheon, a public building in Paris.
Pendulums on his design became popular and there are now hundreds of them on display all over the world. The one at Western Security Bank, at North Broadway and First Avenue North, besides being the only one in Montana, is one of just a handful in the United States inside a private business. Almost all the rest are in museums, libraries, planetariums and similar venues.
The pendulum in Billings owes its existence to Jim Bennett, who in 1978 moved his First Citizens Bank into what had been the J.J. Newberry department store at 123 N. Broadway. In the old department store building, Bennett said, there were escalators leading from the ground floor to the selling floor below. But the escalators were out of order and the bank wouldn’t need them anyway.
So, what to do with this big open space in the middle of his new bank? Bennett’s first thought was to cut out a 25-by-25-foot section of the ceiling and install a chandelier.
Then he thought of the Foucault’s pendulum he had seen as a young man. Bennett was born in 1931 in Havre, when his parents were living on a homestead near Logie, 10 miles southeast of Havre. In 1949, the year Bennett graduated from Chinook High School, he was one of 30 Montana delegates who attended the National 4-H Club Congress in Chicago.
It was his first time out of state, and among the marvels he saw in the metropolis was a Foucault’s pendulum at the Museum of Science and Industry. Almost 30 years later, standing inside his new bank, he thought back to that museum visit.
The only place in the country that installed Foucault’s pendulums then was the California Academy of Sciences in San Francisco. The academy said it could install one for $8,000. You didn’t have to be a banker to know that sounded like a pretty good deal.
So Bennett had the section of ceiling cut out to accommodate the cable that would hold the pendulum’s bob, or weight. The hollow brass bob weighs 235 pounds and swings on a 40-foot steel cable. The pendulum is kept in motion by means of an electromagnetic device.
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