Object of the Month
One of the most interesting features of the clock is its pendulum, which has two cylinders filled with mercury to act as the weight, and can be adjusted to increase or decrease the speed at which it swings. Mercury pendulums, first invented by English clockmaker George Graham in 1721, were developed as a method of avoiding inaccuracies in earlier pendulum clocks caused by expansion and contraction of the pendulum rods due to changes in temperature. Mercury expands with an increase in temperature, and the mercury pendulum uses this property to counteract changes in other parts of the clock by shifting the pendulum's center of mass, thereby maintaining a more even rate of swing and resulting in more accurate timekeeping.
Did You Know?
According to his mother, Jack Kennedy was the “problem child”, forgetful and “invariably late” for meals. Sloppy at home & lazy at school, Jack overcame his problems with spelling & grammar to win the 1957 Pulitzer Prize with his “Profiles in Courage” and the presidential election 3 years later.