The Church performed the useful function of marking the hours at a time when clocks were not widely available. So important was the Church clock, that a lawyer Mr Wight who occupied a house in St Andrew Square altered the building of a house on Princes Street so that his view of St Giles Clock would not be obscured. The original steeple clock had been installed about 1552 but had fallen into disrepair. In 1585 it was replaced by one which came from the Abbey Church of Lindores in Fife at the cost £55. It had two faces with ‘twa hands’. It was built to strike the hours, relieving the bellman of that duty. The clock was set from the time shown on a sundial erected on the south wall of the Church.
In 1721 the clock mechanism was replaced by one from a London firm of clockmakers, much to the annoyance of the Edinburgh clockmakers. This clock was repaired and the minute hand inserted in 1797 by the Edinburgh Clockmaker Thomas Reid. Illustrations of the Steeple at this time show it to have four clock faces. In 1912, the firm of James Ritchie and son, installed a non-dial chiming clock which functions to this day. This clock has no faces for it was felt that the faces destroyed the appearance of the steeple. The hours and quarters are struck on the three bells still in the steeple – the great bell, originally cast in 1460 strikes the hours, and two small bells dating from 1706 and 1728 strike the quarters. The old clock was given to the Museum of Edinburgh, where its mechanism can still be seen.
The old St Giles Clock mechanism by Bradley of London now in the Museum of Edinburgh and the hour and minute hands removed in 1912. Near its original location in the steeple there is a brass plaque which reads ‘L Bradley, Londini Fecit MDCCXXI’
In 1700 a carillon of twenty two musical bells was installed in the steeple. These were rung with hammers played from a key board ‘like a harpsichord’. Defoe wrote that the musician played the keys with ‘strong wooden cases protecting his fingers by which he is able to strike with more force’ – an odd analogy with a harpsichord keyboard! The musician was paid 500 merks a year to play traditional Scottish tunes on the bells for an hour at midday except on Sundays and ‘well earns the money’ according to Defoe. Chambers records that the last player of the bells was ‘a lady of advanced age’. This musical interlude was a popular feature of Parliament Square in those days for ‘their melodious harmony they captivate the Ear and charm the Hearer’ according to one commentator but ‘much better heard from a distance’ according to Defoe. When the controversial Act of Union of the Scottish and English Parliaments came into force on 1 May 1707, the cathedral bells rang out the tune ‘Why should I be so sad on my wedding day.’
Citizens and visitors to Edinburgh were much intrigued by the cathedral bells which much have made a big impression. In his autobiography James Nasmyth (1808-1890) recalled:
One of my greatest enjoyments when a child was in going out with the servants to the Calton…While sitting on the grassy slopes of the Calton Hill I would often hear the chimes sounding from the grand old tower of St Giles….The sounds came over the murmur of the traffic in the streets below. The chime-bells were played every day from 12 till 1 – the old-fashioned dinner-hour of the citizens. The practice had been in existence for more than 150 years. The pleasing effect of the merry airs, which came wafted to me by the warm summer breezes, made me long to see them as well as hear them.
My father was always anxious to give pleasure to his children. Accordingly, he took me one day as a special treat to the top of the grand old tower, to see the chimes played. As we passed up the tower, a strong vaulted room was pointed out to me, where the witches used to be imprisoned. I was told that the poor old women were often taken down from this dark vault to be burnt alive! …. What a fearful contrast to the merry sound of the chimes issuing from its roof on a bright summers day…
There was a wild rumbling thumping sound overhead. I soon discovered the cause of this when I entered the flat where the musician was at work. He was seen in violent action, beating or hammering on the keys of a gigantic pianoforte-like apparatus. The instruments he used were two great leather-faced mallets. …. Each key was connected by iron rods with the chime-bells above.”
James Nasmyth was the son of the artist Alexander Nasmyth and was himself a competent artist but is chiefly remembered as an engineer who invented the steam hammer.
R L Stevenson did not share Nasmyth’s enjoyment of the church bells. In Edinburgh, Picturesque Notes he wrote:
I have heard the chimes of Oxford playing their symphony in a golden autumn morning, and beautiful to hear. But in Edinburgh all manner of loud bells join, or rather disjoin, in one swelling, brutal babblement of noise.
Indeed, there are not many uproars in the world more dismal than that of the Sabbath bells in Edinburgh – a harsh ecclesiastical tocsin. How many of them might rest silent in the steeple, how many of these ugly churches might be demolished and turned once more into useful building material, if people who think almost exactly the same thoughts about religion would condescend to worship God under the same roof! 
By 1865 the bells were in a sorry state and the tunes unrecognizable. The last bell player was a lady, Catherine Macleod, who succeeded her father in the post. Fortunately she was very deaf. The chime was dismantled and sold in 1890; one of the bells remains on display within the Cathedral. Another larger bell also remains on display with a Latin inscription which in English reads ‘O Mother of God; remember me, 1504’. It is described as the ‘vesper bell’ and is one of the few relics to have survived the clearance of the Catholic icons at the time of the Reformation.
 Chambers Traditions of Edinburgh p8
 Chambers Traditions of Edinburgh p178-9
 Marshall, R K (2009) p94
 The chime of 15 bells was ordered in 1698 to be made by an Edinburgh founder, John Meikle, but for some reason this was increased to 23 bells for which he was paid 1000 pounds Scots.
 Defoe, D (1991) A Tour through the Whole Island of Great Britain p313
 Maitland p273 . Maitland added that ‘if there were added a few Bells of deeper Note, they would be rendered a complete Set, and perhaps would equal, if not excel every Set of their kind elsewhere.’
 Nasmyth, J p70-73
Stevenson, R L in Edinburgh, Picturesque Notes