BIG BEN

Evening Post, Volume CX, Issue 78, 29 September 1930, Page 17

BIG BEN

Sir Prank Dyson, British astroiio- } mer-Boyal, writing to "Tho Times," [ directs attention to the excellent per- ji formaii.ee of Big Ben, the famous clock I in the tower of the Britiah Houses of I Parliament. During the year which | ended on 30th April it was compared \ on 288 days at the Royal> Observatory, | and on only twenty-one days did its » error roach more than lsec, the maxi- I mum being I.4sec. This is an admit- | able record for.-n tower clock which ia i going continuously. | The error is kept so small by means £ of a tray which is fixed about half-way t dowu the pendulum. When the clock f is losing slightly a'""half-penny or a | penny is placed in the tray. This £ makes the pondulum vibrate slightly I more quickly, and gradually brings the < clock to time. If the clock is gaining a | half-penny or a penny is removed. As ( it takes a fifth of a second for the I sound of Big Ben to reach the bottom | of the tower and about a couple of | seconds to reach Trafalgar Square, the | limits of reasonable accuracy have been | reached. It is only for astronomicai I purposes that more is required, El