Foreign News: Benpenny

Probably the best known timepiece in the world is Big Ben, giant clock atop the Houses of Parliament. His Majesty’s Astronomer Royal, Sir Frank Watson Dyson revealed in London last week that Big Ben was not only one of the most famed, but, for an old clock, one of the most accurate of timepieces. After a 288-day comparison with the Royal Observatory at Greenwich (Astronomer Dyson’s special charge) it was found that Big Ben’s maximum deviation was only 1.4 sec. per day, that only on 21 days in the whole period of observation did the deviation exceed 1.o sec. No intricate mechanical adjustments but a mere pocketful of small change maintains the accuracy of Big Ben.* “Whenever the clock is losing slightly,” explained Astronomer Royal Dyson, “we just drop a ha’penny or a penny on a tray fixed about half way down the pendulum. If the clock is gaining, we take the penny out. As it takes a fifth of a second for the booming of Big Ben to reach the street, and two seconds to reach Trafalgar Square, we may consider that the limits of reasonable accuracy have been reached.”

*Last year while Big Ben’s works were being overhauled and cleaned, two workmen perched behind the glass face for several hours, pushing the minute hand around.