Oh! Is that the time?

Back in the Eighteenth Century when Lord Dandy-Lyon decided to commission a clock for Ragwort Hall, his palatial estate in the country, he would have visited a specialist clock-maker to have it designed and made to order.  It might be a long-case clock for the hallway or a tower clock to be installed above the stable block.  But, whatever, the situation, it could be the first clock to be set up at his home that was both reliable and accurate (many clock-makers might disagree).  How then, to get the time right?  There are no radios giving time pips every hour and no other reliable clocks for any number of miles.  The answer is simple, the clock-makers will make his Lordship a sundial to go with the clock.  The clock-makers will check the exact location of Ragwort Hall, work out its Latitude (degrees North or South of the Equator) and design a sundial with the Gnomon fixed at the correct angle.  When this is set up properly (and is pointing due North) its shadow will show LOCAL time whenever the sun is shining.  That way, his Lordship, or his trusty servants, will be able to check the clock time periodically.

Local time is significant because, until the arrival of the railways and the telegraph system of communications, noting the time was a local matter and what time it was on the other side of the country was of no concern.  To demonstrate this: the Longitude for Land’s End is 5° 4' 4.2" West (of Greenwich) and for Lowestoft it is 1° 45' 5.72" East; which means that (according to my calculations) Local Noon {1} in Lowestoft is 29 minutes and 48 seconds earlier than Local Noon in Land’s End.

Memo to Lord Dandy-Lyon: “Train your servant before you Trust your servant.”

Royal Collection Trust / © Her Majesty Queen Elizabeth II 2020

Move forward now to the early Nineteenth Century and imagine yourself aboard a Royal Navy Battleship – the HMS Vulcan.  Captain Fearless and his officers will be on the quarter-deck (precursor to a modern-day ship’s bridge); one side will be the Captain’s territory and the other side for his Lieutenants, the time is fast approaching mid-day.  Almost all of the officers will have their sextant with them and will be using this to get a sighting of the Sun and the horizon to determine when it has reached its highest point, making it mid-day, and the angle between the Sun, the ship and the horizon.  When the officers have agreed between themselves, the First Lieutenant will approach the Captain and advise that they make it Noon, the Captain will agree and thus Noon it is.  Bells will be rung, hourglasses will be turned and the ship’s new day will officially begin.  The navigators, at this point, will be charging down to the chart-room with their calculations and will proceed to plot their location.

The navigators would use their charts, Nautical Almanacs and chronometer (set accurately to display the time at Greenwich {2} or their base port throughout their voyage) to determine their position at sea (Latitude and Longitude) and bearing.  Then they can advise the Captain of their progress and position.  Obviously, as it takes a while to collect their observations and make their calculations, they cannot pinpoint their exact position at sea, but they will be fairly close.

Nowadays, however, fixing the position of ships and planes can be carried out at any time, regardless of cloud cover (which can stymie sextants), using modern satellite technology and time measurement.  Time is measured now by the vibration of caesium atoms and this is regarded scientifically as the most precise means possible of maintaining accuracy. 

In Great Britain, Greenwich Mean Time and British Summer Time are the two official times used. Whereas overseas, Co-ordinated Universal Time - which, to the layman, is effectively the same as GMT - is the standard for setting timekeeping around the world - and in manned space vessels.

With all this accuracy, you can check the time, to a fraction of a second, at any time, night or day.  But, do we really care about the exact time?  Ask somebody what the time is and, as like as not, they may say “Oh, about a quarter past seven.”  Which gives plenty of leeway!  But, if you are racing to catch a train or are a pub landlord about to announce “Time, gentlemen, please!” then the exact time is critical.

We have four mechanical clocks and one battery clock in our living room, each of which is true unto itself and we love them all, their ticking, their chimes and observing their intricate movements are a joy to hear and to behold.

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 {1} Noon – or mid-day – is the precise moment that the Sun is at its highest point in the sky that day.  If you are in the Northern Hemisphere, the Sun will be to your South and your shadow (pointing North) will be shorter than at any other time in the day.  The Sun will never be directly overhead, unless you live in the Tropics. 
The Tropic of Cancer is 23ﹾ 28’ North of the Equator and Capricorn is the same distance to the South.  The Latitude of Lizard Point in Cornwall is 49° 57' 19.19" North and for Eastbourne it is 50° 46' 7.36" North; thus, in the United Kingdom, we are a long way from seeing the Sun too high in the sky, being closer to the North Pole than the Equator.


 {2} In the Nineteenth Century, Greenwich Mean Time was adopted as Great Britain’s “official” time by Act of Parliament: The Statutes (Definition of Time) Act 1880.  Subsequently repealed by The Interpretation Act 1978.  British Summer Time was first enacted legally in 1922 (after being used as a temporary measure in the Great War) and British Standard Time in 1968, but these acts were repealed by The Summer Time Act 1972. 

Excellent reading:
AC GARDNER     “Teach Yourself Navigation”.  The English Universities Press Ltd – Second Edition 1973
AP HERBERT       “Sundials Old & New”.  Methuen & Co Ltd - 1967
Dava SOBELL      “Longitude – The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time”.  Fourth Estate Ltd - 1996
 

With thanks to staff at the National Archives and Worthing Library (Reference Department) for their kind guidance by pointing me in the right direction in my researches and also to staff at the Royal Collection Trust and the British Sundial Society.

The cartoon came from the February 1994 Bulletin of the British Sundial Society; I have not been able to track down who drew it but if you know who does, please let me know and I will be delighted to acknowledge him or her.  
The cartoon is, in fact, a copy of a 19^th century drawing which is in the Royal Collection, if you would like to look at the original, please click here:  Thomas Rowlandson - 1808.

 
The Royal Collection is a vast repository of wonderful pieces of art and I would recommend using the link as a way into explore this wonderful Collection.