Time Balls, like this one in Semaphore, were a common sight in port areas around the world before the introduction of wireless telegraphy. The first such Time Ball was constructed at Greenwich, England, in 1833 with this one in Semaphore being built in 1875.
At precisely 1pm daily, the black ball would drop, signalling ships in the harbour to rate their chronometers and other vital navigation instruments. Interestingly, and following British tradition, the ball did not fall at noon as Greenwich astronomers were otherwise engaged at that hour. American Balls, on the other hand, usually dropped at noon.
The Semaphore Time Ball was built, adjacent to the old signal station, by Mr. Henry Burge and the first ball dropped on the press of an electric button in the Observatory in the West Parklands, Adelaide, by Hon. W. Morgan on 2 August 1875.
To ensure ships masters were ready to rate their time pieces at 1pm, the ball was manually raised to halfmast at five minutes to 1pm, and to the masthead at three minutes to 1pm – a total distance of 13 feet. The 5-6ft diameter ball was then dropped by electric command from the Observatory at precisely 1pm.
Replaced by wireless telegraphy, use of the Time Ball discontinued on 1 February 1932 (I originally wrote this review precisely 82 years from that date on 1 February 2014).
The tower became dilapidated over time but thankfully in 1992 it was restored and a mechanism installed that operates the Time Ball by electric motor. The ball still drops at 1pm daily.
Walk up to the tower and enjoy very pleasant views down to the beach (last picture attached). The grass area by the Sentinel is a favourite spot of mine for a picnic.
Address: Beach end of Semaphore Road
Directions: Just inland from the Jetty