Timeline was based on a series of recordings of my own voice sounding three harmonising notes around the key of ‘G#’, played simultaneously from six sites across the city at one o’clock. The sound was very short, lasting just under ten seconds, but it cut across all of the ambient sounds, like an aural clock. The sound was synchronised to travel from the first site at Calton Hill to the next at Calton Cemetery and on through North Bridge and Waverley Bridge and across the roof of the National Galleries of Scotland and on to Edinburgh Castle. There was a slight delay between the recordings so it seemed as if there was a domino effect of the sound traveling across the city.
In 1852, Edinburgh installed a time ball at the top of Nelson’s Monument on Calton Hill, to enable the sailors in Leith docks and the Firth of Forth to adjust their chronometers. In 1861, a master clock on Calton Hill was linked by an overhead electric cable to a clock at Edinburgh Castle. This enabled the one o’clock gun at the castle to be fired automatically at exactly one o’clock. The electric cable linking the castle and Calton Hill was 1,225 metres long. It passed over Waverley Valley, without any support, at the height of 73 metres. In the 1860s, Time Gun Maps were published in the Edinburgh & Leith Post Office Directories to show the time taken for the sound of gunfire to travel across Edinburgh.