“Truly impressed – and I’m a watch geek, so that’s saying something”
In retrospect, that was probably rather a sarcastic thing to write in the Palace of Westminster’s visitor book, but I was genuinely bowled over by my experience last Sunday, despite the early hour and my late night before. From scaling all 334 steps of the Great Clock Tower and watching Dent’s mighty movement whirring away with its governor fans click-clacking overhead; to peering out of those world-famous clock faces across a sprawling, sunkissed London town, before standing mere inches from Big Ben and its four melodic counterparts as they bonged-out 10 o’clock – this was tantamount to the Hajj for this watch anorak. Desperate to immerse ourselves fully in the Big Ben experience, my mate Pete and I even spurned the offer of ear plugs, bearing the full force of that 13.7-tonne bronze bell at point-blank range (audible for four and a half miles) and bathing in the deep, subsonic resonance of the iron infrastructure for minutes after the tenth bong had faded. Not even the strains of YMCA, pounding out from the finish line of a 10km fun run on Westminster Bridge below could detract from this most reverent of horological experiences.
Although any UK resident can write to his or her MP and request a guided tour of Big Ben (smug pedants be gone, by the way – it’s now officially acceptable to refer to the whole clock by the big bell’s popular nickname) mine was actually one of several being held this summer in celebration of Big Ben’s 150th anniversary. In an age when the most obscure of milestones are hyped beyond comprehension (40 years since the Moon landing? Why 40?) it’s amazing so little has been made of Big Ben’s one and a half centuries – especially when you consider what an icon this clock actually is. No clichéd Hollywood establishing montage of London would be complete without a policeman / vicar / Hugh Grant cycling past the Clock Tower; Radio 4’s hourly news broadcasts would surely lack all gravitas without its opening salvo of bongs; London’s skyline would merely be anodyne without SW1’s tower (paired with EC1’s St Paul’s dome of course).
Once through the airport-style security gates and duly reminded with an air of forboding that this tour was not for the physically infirm or claustrophobic, we commenced our ascent of the Tower – a phallic masterpiece positively bulging with history.
The view from the bottom of the 334 steps. Deep breath…
The view from the top. Well worth the slog
Denison and Dent’s Clock
It all began with a terrible fire, which destroyed most of the Palace of Westminster in 1834. Out of the 97 designs submitted for the new Palace, master Gothic architect Sir Charles Barry’s was successful and construction of the Clock Tower began in September 1843. Barry was no clockmaker though, and he sought advice from the Queen’s Clockmaker and good buddy, Benjamin Lewis Vuillamy.
Other respected clockmakers, such as the marine chronometer pioneer Edward John Dent, wanted the chance to be involved though, and disputes quickly broke out (this was to set the tone for the entire project – by completion, the chief contractors for the Tower had been reduced to corresponding via letters in The Times). In 1846 therefore, a competition was held to decide who should build the clock. Astronomer Royal, Sir George Airy – who had awarded Dent’s first commission in 1814 to build the Admiralty’s Standard Astronomical Clock – was appointed referee and set out unprecedented standards for the clock to meet.
· the first stroke of each hour to be accurate to within one second
· the clock’s performance to be telegraphed twice a day to Greenwich Observatory
Airy’s demanding standards led to delays that lasted seven years. Most master clockmakers of the day complained that such a level of accuracy was impossible for a clock of its size – at 4.2m and 2.7m, and 100kg and 300kg, the minute and hour hands are particularly susceptible to the elements, acting as windmills on all four clock faces, feeding unwanted energy from the rain and wind back into the delicate movement. The best that could be hoped for, they said, was three minutes a day.
Airy appointed Edmund Beckett Denison – barrister, MP and gifted amateur horologist –to design the clock, then in February 1852, Dent was appointed to build the clock to Denison’s own design, mostly because his quote of £1,800 was half that of Vulliamy’s, but also because Dent had made an impression the year before with a turret clock on display at London’s Great International Exhibition. It won the Council Medal for Horology and after the Exhibition it was erected at King’s Cross Station, where it remains (and where the revived Dent watch brand received its latest public clock commission, for the Eurostar terminal).
Dent died in 1853 and his stepson, Frederick, completed the clock in 1854 for a final bill of £2,500. Working along similar lines to a grandfather clock, it is regulated by a 2-second, 4.4m pendulum and powered by three stone weights totalling 2.5 tonnes, which are wound up on Mondays, Wednesdays and Fridays.
If you watch Dent’s Big Ben clock movement long enough, you’ll eventually figure out how it all works, so logically is everything laid out. Watchismo Times regulars probably won’t resist comparing its lateral array with Ruchonnet’s Cabestan
The “governor” fans above the movement use air resistance to regulate the rate with which the chiming mechanism unwinds
Crucially, Dent’s clock is accurate to within one second per day – just as Airy wanted – and as such Big Ben remains the largest and most accurate striking mechanical clock in the world.
Pre-decimal-currency pennies are still used by the Palace of Westminster’s three appointed clockmakers to regulate the clock mechanism: adding one penny causes the clock to gain two-fifths of a second in 24 hours.
The achievement of such accuracy was partly thanks to the British government’s perennial inability to get anything done on time (or budget). The Clock Tower’s construction was delayed for 5 years, and until its installation in 1859, Dent’s 5-tonne behemoth of a mechanism was kept at his factory on the Strand. In the meantime, Denison tinkered, most notably inventing the 'Double Three-legged Gravity Escapement' in the process (later known as the Grimthorpe Escapement when Denison was made Baron Grimthorpe in 1886). Since used in turret clocks all over the world, this revolutionary mechanism is key to Big Ben’s world-beating accuracy, ensuring the swing of the pendulum is unaffected by the weather’s influence on the hands. In an agonizingly simple but revolutionary manner, Denison’s gravity escapement isolates the pendulum from the going train. The energy from the going train alternately lifts two rocking gravity arms, which, when falling, give constant and independent impulses to the pendulum.
This Flash animation showing the inner workings of Big Ben, is brilliant --> Click here
No photography allowed up the Tower – but I managed to sneak in a clandestine snap (above) with my mobile in the space between the clock room and the clock faces. Each face is 7m in diameter and has 312 separate pieces of pot-opal glass panels framed by gun metal. Illumination of each dial is performed in a delightfully rudimentary manner by a bank of 28 oversized energy-efficient bulbs at 85W each. Lifetime of each bulb is 60,000 hours
The Bells! The Bells!
Denison also became involved in the design of the bells for the clock, in particular Big Ben. Until the Westminster clock tower, the largest bell ever cast in Britain was Great Peter in York Minster, weighing 10.3 tons. (Now, Big Ben is only superseded in Britain by Great Paul at St Paul’s Cathedral down the road.)
But Denison was adamant that his own design, method and alloy recipe would allow a larger bell to be created. Eventually, a 16-ton monster was cast at the Warner & Sons foundry in Stockton-on-Tees in August 1856. Too wide to be transported by rail, it arrived at the Port of London by sea, from where it was pulled across Westminster Bridge by 16 white horses.
The bell was hung in New Palace Yard. It was tested each day until 17 October 1857 when a 1.2m crack appeared. No-one would accept the blame. Theories included the composition of the bell’s metal or its dimensions. Warners blamed Denison for insisting on increasing the hammer’s weight from 355kg to 660kg.
Warners asked too high a price to break up and recast the bell so George Mears at the Whitechapel Foundry was appointed. The second bell was cast on 10 April 1858.
This bell was 2.5 tonnes lighter than the first. Its dimensions meant it was too large to fit up the Clock Tower’s shaft vertically so Big Ben was turned on its side and winched up. It took 30 hours to winch the bell to the belfry in October 1858. The four quarter bells, which chime on the quarter hour, were already in place.
Big Ben rang out on 11 July 1859 but its success was short-lived. In September 1859, the new bell also cracked and Big Ben was silent for four years. During this time, the hour was struck on the fourth quarter bell. The dispute went public and resulted in two libel cases against Denison, who was found to have befriended one of the technicians at the foundry, got him drunk and bullied him into giving false testimony that the fault had been due to poor workmanship and concealed filler. The cantankerous lawyer lost both cases and a close examination of Big Ben in 2002 found that there was no filler in the bell. As one contemporary of Denison put it: "Zealous but unpopular, self-accredited expert on clocks, locks, bells, buildings as well as many branches of law, Denison was one of those people who are almost impossible as colleagues, being perfectly convinced that they know more than anybody about everything - as unhappily they do."
In 1863, a solution was found to Big Ben’s silence by Sir George Airy, the Astronomer Royal:
· Big Ben was turned by a quarter turn so the hammer struck a different spot
· the hammer was replaced by a lighter version
· a small square was cut into the bell to prevent the crack from spreading
The total cost of making the clock and bells and installing them in the Clock Tower reached £22,000.
The famous “Westminster chimes” – emulated on a smaller scale by Grande Sonnerie wristwatches – are struck by four quarter bells positioned around Big Ben tuned to G, F, E and B. Their tune is based on Handel’s Messiah, a phrase from the aria I Know that My Redeemer Liveth. They were set to verse and the words are inscribed on a plaque in Big Ben’s clock room:
All through this hour
Lord be my Guide
That by Thy Power
No foot shall slide
Why “Big Ben”?
Officially, the Clock Tower’s bell is called the Great Bell though it is better known by the name 'Big Ben'.
There are two theories for this name’s origin. These are that the Great Bell was:
· named after Sir Benjamin Hall, First Commissioner for Works 1855-1858, whose name is inscribed on the bell
· named after Ben Caunt, a champion heavyweight boxer of the 1850s
The first theory is thought to be the most likely.
Stop – Hammer Time!
Stoppages are rare, but the most notable are:
2007: the longest suspension of the hour strike (Big Ben) since 1990. Big Ben's famous 'bongs' were silent for seven weeks in 2007, allowing essential maintenance work on the clock mechanism to take place. From 11 August to 1 October, an electric system kept the clock moving, but Big Ben, the name for the Great Bell, and the quarter bells were quiet. This was the final phase of a programme of planned works to prepare for the Great Clock's 150th anniversary in 2009.
October 2005: The clock mechanism was also suspended for two days in to allow inspection of the brake shaft.
Over the years, the clock has been stopped accidentally on several occasions - by weather, workmen, breakages or birds. The most serious breakdown occurred during the night of 10 August 1976 when part of the chiming mechanism disintegrated through metal fatigue, causing the mechanism to literally explode under its own immense forces, dropping its weights to the base of the Tower with a noise that the policeman on duty initially reported as being an IRA bomb. The Great Clock was shut down for a total of 26 days over nine months - the longest break in operations since it was built - until it was fully repaired.
The Secret’s Out
But despite Big Ben’s remarkable, unflagging accuracy, one burning question remains: how is it checked? Mike McCann, who rejoices in the title of Keeper of the Great Clock, gives a slightly embarrassed laugh when he is asked. The answer is that he does what everyone else does: he rings up the speaking clock. He does so from the phone in the clock room at five to the hour precisely, starting a stopwatch on the third pip, and then goes up the belfry to see when the hammer on Big Ben strikes the hour. Simple, if not technologically sophisticated.
See also on Watchismo: Alex Doak’s report on modern Dent’s most recent public clock commissionSources:
Related "Alex Doak" Posts at The Watchismo Times;
UnBNBelievable - Confrérie Horlogère
Sarpaneva's Black Moon Rising
Plenty of Scratches but only one Dent
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