Navigators had to know the time accurately in order to work out longitude so they could plan the safest and shortest sailing routes. Astronomers calculated the time at observatories.

The new time balls of the nineteenth century allowed ships' captains to set their chronometers from a distance, without actually going to an  observatory.

Our timeball, which was conserved in 2009, is a great example of  the work of Maudslay, Sons and Field, supported by eminent  astronomer Charles Piazzi Smyth, who helped devise and install it in 1852. Piazzi Smyth continued to work out the time and triggered the ball drop himself, later devising an automatic system to drop it.

Why was time so important?

It was all about navigation. Latitude is easy – read the angle to the pole star. For longitude – they had worked out maps of the stars and lots of tables; however to find out exactly where you were you had not only to look at the stars and look at the star charts, you had to know what time it was too. If your chronometer was even a few seconds out you could be a mile out in your calculations. Not much in the size of the Atlantic, but a long way if you were headed for a particular port, or trying to avoid rocks.

Ships that could find the shortest, safest routes around the globe were the most profitable. Britain’s wealth in the nineteenth century was powered by Empire and the industrial revolution – raw materials from across the globe worked in British factories and mills; finished goods exported to all countries. Time delays, losses of ships, losses of cargoes, damage in transit – these were the demons that turned profit to loss. The profit was put into great public buildings and public works like water and sewage schemes and railways, as well as into private wealth and consumption.

The world we live in today would have been different without it, and the men who worked in this building to set the time were a part of that whole sequence of events. The first real invention that improved navigation was Harrison’s chronometer, which was much more accurate than earlier ones. The second was a network of observatories like this one around the globe, staffed by astronomers, who worked out time exactly. Ship’s captains could then check their chronometers routinely before setting off on the next leg of their voyages. Before the installation of the time ball, ships captains walked up the hill to get the time. With the time ball in place, they could stand on deck in the Forth and get an accurate time check. It was so successful there was an immediate campaign for an audible signal for foggy days, and 9 years later, in 1861, the one o'clock gun was introduced.

New technology was applied everywhere in the Victorian era. Astronomer Piazzi Smyth could even drop the time ball automatically, though it had to be raised manually first. Read Piazzi Smyth’s note about timings for winding the ball up for the drop. When the gun was introduced a cable was run across from Calton Hill to the castle and the gun and time ball were both fired simultaneously from the Observatory. A high level cable was run from the Nelson Monument to the castle in a single span in 1861, and in 1865 it was replaced by a thicker cable. The possible dangers of this long cable must have been immense and in 1873 it was re-routed across the tops of buildings on the North Bridge and up the Royal Mile to the Castle. Eventually it was mostly replaced by a low level cable with repeater clocks, initially run from Calton Hill and later run from the Blackford Hill Observatory, which continued in use until the beginning of the 20th century.

At the same time – ie the 1850s and 60s - the railways were introducing a standardised time across the country. For a brief period the astronomer on Calton Hill supplied accurate times not only to Edinburgh, but to Glasgow, Dundee and Newcastle. By the 20th century radio had replaced the need for mariners to check with astronomers and before the end of the 20th century GPS enabled precise positional information to be easily obtained.