29. Time Ball Tower – The Esplanade
‘The Sentinal of Semaphore’ – this solid stone structure was built in 1875. At 1pm daily, the black ball drops, signalling ships to rate their chronometers, vital navigation instruments. Similar towers were set up in many cities around the world.
The first Time Ball was built at Greenwich in 1833. The original balls were dropped at 1pm, that being chosen because the astronomers were busy observing the meridian. American Time Ball were usually dropped at noon.
The Semaphore Time Ball was built by Mr. Henry Burge, the successful tenderer, upon the concrete foundation laid by Mr. Hill. Its duties began on August 2. 1875, by the pressing of an electric button at the Observatory in the West Parklands, Adelaide, by Hon. W. Morgan.
The ball was raised manually to halfmast at five minutes to 1pm, and to the masthead at three minutes to 1pm – a total distance of 13 feet. A ball in diameter of six feet was listed in 1898, although modern sources put it at five feet. The ball was then dropped by electric command from the Observatory at precisely 1pm.
A similar service became available in 1920 when a Time Ball was erected on the dome of the Harbour Board Building on Lipson Street in Port Adelaide. Replaced by wireless telegraphy, both of these services were discontinued from February 1, 1932.
In 1992, the Tower was restored and a mechanism installed that operates the Time Ball by electric motor. The ball still drops at 1pm daily.