Tag Archives: firth of forth

Edinburgh’s Time Machine (2)

The falling timeball (see here), as a means of indicating the time to ships in the Firth of Forth and to the gunner on the ramparts of Edinburgh Castle, hit a snag. Edinburgh and its environs suffer dense sea mists known locally as the haar (think ‘Arr, Jim lad’, Robert Newton’s interpretation of LJS by RLS…or the much better take-off by Tony Hancock – and if you don’t know what I’m on about, I’m sure Google will come to the rescue). The haar obscures the Time Ball, rendering it useless both to ships at sea and to the one-o’clock gunner on the castle ramparts, who probably had trouble finding his gun in the mist anyway. New technology came to the rescue. A wire was strung from the observatory to the castle (the mind boggles at this) so that at precisely 1pm somebody in the observatory could throw a switch to actuate an electric bell in a box on the wall beside the gunner on the ramparts. Though the Time Ball could not be seen from ships, the bang could be heard.

These days the gunner tugs a lanyard. Back then he would have lit a fuse. Did the delays matter? Did someone calculate the time it would take for the electricity to reach the bell (a bit more than the speed of light, probably) and the time for the fuse to burn down and fire the gun? You bet they did. From small beginnings like this, men flew to the moon.

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Edinburgh’s Time Machine*

My apologies to Michael Caine, but a lot of people do know this. Edinburgh has a One O’Clock gun. It is high on the castle walls and booms out over the city at precisely 1pm (except on Sundays, Good Friday and Christmas Day, when apparently time is of little importance). If you happen to be walking along Princes Street when the gun is fired you will notice a dozen or so people around you glance at their watches, despite the fact that the time on some of the most sophisticated of these will be set automatically by radio from Frankfurt (and also, believe it or not, from Cumbria). What a lot of people may not know is that the time-setting One O’Clock gun is the audible representative of a visual version on Calton Hill.

Let me explain. Once upon a time, ships moored in the Firth of Forth had chronometers, accurate clocks that enabled their navigators, using sextants, to determine their precise position anywhere on the Globe. The One-O’Clock gun allowed them to set their chronometers accurately – accurately because those in the observatory on Calton Hill knew about such things. A couple of minutes before 1pm the Time Ball (the black ball at the top of the Nelson Monument, adjacent to the observatory and visible from the Castle and to those looking east along Princes Street, see photo) was wound to the top of the white mast. At precisely 1pm it fell. Seeing this, the gunner on the castle ramparts lit the fuse on his cannon (or as he does today, pulled the lanyard on his howitzer). There was, and still is, a very loud bang. It did, and still does, scare the living wosnames out of tourists.

To be continued…

*This, as you may know, is the title of an H G Wells novel. If you want to buy a first edition, there is one for sale here. Note the price.

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