The Clock
In 1848, the Astronomer Royal, Sir George Airey, and barrister Edmund Denison (who was an amateur watchmaker) took charge of designing the Great Clock. Clockmaker Edward Dent had the job of building it.
Denison collaborated closely with Edward John Dent who constructed the clock. Dent had completed a very successful public clock for the Royal Exchange under Airy's direction and was the clockmaker of choice of both Denison and Airy. Turret clocks were not his main interest and Dent had won awards for his development of the marine chronometer. Both Denison and Airy were impressed with his progressive approach. Dent died before the clock was completed and his nephew, Frederick Rippon became head of the firm having satisfied his uncle's condition that he change his surname to Dent. Frederick Dent completed the work and installation after his uncle's death, and the inscription on the frame of the clock bears his name.
Clock Tower
Photography by Deryc Sands.Clock Tower
Clock Tower From Parliament Square
Image supplied by House of Commons Information OfficeThe Clock Tower is 96.3 metres tall and is a turret clock structure located at the northeastern end of the Houses of Parliament building in Westminster, London. This famous tower is colloquially known as Big Ben, but this name actually belongs to the clock's main bell.
The tower has also been referred to as St. Stephen's Tower or The Tower of Big Ben, in reference to its bell.
The tower has also been referred to as St. Stephen's Tower or The Tower of Big Ben, in reference to its bell.
St Stephen's Tower
Structure
The tower was raised as a part of Charles Barry's design for a new palace, after the old Palace of Westminster was destroyed by fire on the night of 16 October 1834. The tower is designed in the Victorian Gothic style, and is 96.3 metres (316 feet) high.
The first 61 metres (200 feet) of the structure is the clock tower, consisting of brickwork with stone cladding; the remainder of the tower's height is a framed spire of cast iron. The tower is founded on a 15 by 15 metre (49 by 49 foot) raft, made of 3-metre (9-foot) thick concrete, at a depth of 7 metres (23 feet) below ground level. The tower has an estimated weight of 8,667 tonnes (9,553 tons). The four clock faces are 55 metres (180 feet) above ground.
Due to ground conditions present since construction, the tower leans slightly to the northwest, by roughly 220 millimetres (8.66 inches). Due to thermal effects it oscillates annually by a few millimetres east and west.
The first 61 metres (200 feet) of the structure is the clock tower, consisting of brickwork with stone cladding; the remainder of the tower's height is a framed spire of cast iron. The tower is founded on a 15 by 15 metre (49 by 49 foot) raft, made of 3-metre (9-foot) thick concrete, at a depth of 7 metres (23 feet) below ground level. The tower has an estimated weight of 8,667 tonnes (9,553 tons). The four clock faces are 55 metres (180 feet) above ground.
Due to ground conditions present since construction, the tower leans slightly to the northwest, by roughly 220 millimetres (8.66 inches). Due to thermal effects it oscillates annually by a few millimetres east and west.
The Clock Tower from Westminster Bridge
Photography by Deryc SandsClock Mechanism
This is the clock mechanism within the Clock Tower. In 1848, the Astronomer Royal, Sir George Airey, and barrister Edmund Denison (who was an amateur watchmaker) took charge of designing the Great Clock. Clockmaker Edward Dent had the job of building it.
Clock Mechanism
Photography by Deryc SandsReliability
The clock is famous for its reliability. This is due to the skill of its designer, the lawyer and amateur horologist Edmund Beckett Denison, later Lord Grimthorpe. As the clock mechanism, created to Denison's specification by clockmaker Edward John Dent, was completed before the tower itself was finished, Denison had time to experiment. Instead of using the deadbeat escapement and remontoire as originally designed, Denison invented the double three-legged gravity escapement. This escapement provides the best separation between pendulum and clock mechanism. Together with an enclosed, wind-proof box sunk beneath the clock room, the Great Clock's pendulum is well isolated from external factors like snow, ice and pigeons on the clock hands, and keeps remarkably accurate time.
The idiom of putting a penny on, with the meaning of slowing down, sprang
from the method of fine-tuning the clock's pendulum by adding or subtracting penny coins. Even to this day, old pennies, phased out of British currency by the 1971 decimalisation, are used.
Despite heavy bombing the clock ran accurately throughout the Blitz during World War II.
It slowed down on New Year's Eve 1962 due to heavy snow, causing it to chime in the New Year 10 minutes late.
The clock had its first and only major breakdown in 1976. The chiming mechanism broke due to metal fatigue on 5 August 1976, and was reactivated again on 9 May 1977. During this time BBC Radio 4 had to make do with the pips.
It stopped on 30 April 1997, the day before the general election, and again three weeks later.
On Friday, 27 May 2005, the clock stopped ticking at 10.07 p.m., possibly due to hot weather (temperatures in London had reached an unseasonal 31.8ºC/90ºF). It resumed keeping time, but stalled again at 10.20 p.m. and remained still for about 90 minutes before starting up again.
On 29 October 2005, the mechanism was stopped for approximately 33 hours so that the clock and its chimes could be worked on. It was the lengthiest maintenance shutdown in 22 years.
In 2005, a terrorist manual was found in the home of Abu Hamza al-Masri, marking Big Ben, the Statue of Liberty and the Eiffel Tower as terrorist targets. In his trial at The Old Bailey in 2006 he denied all knowledge of their being targets.
Big Ben's "Quarter Bells" were taken out of commission for four weeks starting at 0700 hrs GMT on 5 June 2006 as a bearing holding one of the quarter bells was damaged from many years of wear and needed to be removed for repairs. During this period, BBC Radio 4 broadcast recordings of British bird song followed by the pips in place of the usual chimes.
The idiom of putting a penny on, with the meaning of slowing down, sprang
from the method of fine-tuning the clock's pendulum by adding or subtracting penny coins. Even to this day, old pennies, phased out of British currency by the 1971 decimalisation, are used.
Despite heavy bombing the clock ran accurately throughout the Blitz during World War II.
It slowed down on New Year's Eve 1962 due to heavy snow, causing it to chime in the New Year 10 minutes late.
The clock had its first and only major breakdown in 1976. The chiming mechanism broke due to metal fatigue on 5 August 1976, and was reactivated again on 9 May 1977. During this time BBC Radio 4 had to make do with the pips.
It stopped on 30 April 1997, the day before the general election, and again three weeks later.
On Friday, 27 May 2005, the clock stopped ticking at 10.07 p.m., possibly due to hot weather (temperatures in London had reached an unseasonal 31.8ºC/90ºF). It resumed keeping time, but stalled again at 10.20 p.m. and remained still for about 90 minutes before starting up again.
On 29 October 2005, the mechanism was stopped for approximately 33 hours so that the clock and its chimes could be worked on. It was the lengthiest maintenance shutdown in 22 years.
In 2005, a terrorist manual was found in the home of Abu Hamza al-Masri, marking Big Ben, the Statue of Liberty and the Eiffel Tower as terrorist targets. In his trial at The Old Bailey in 2006 he denied all knowledge of their being targets.
Big Ben's "Quarter Bells" were taken out of commission for four weeks starting at 0700 hrs GMT on 5 June 2006 as a bearing holding one of the quarter bells was damaged from many years of wear and needed to be removed for repairs. During this period, BBC Radio 4 broadcast recordings of British bird song followed by the pips in place of the usual chimes.
Clock Tower At Dusk
The Great Bell - Big Ben
Big Ben, officially known as the Great Bell of Westminster, is the largest bell in the tower and part of the Great Clock of Westminster.
The name Big Ben was first given to a 14.5 tonne (16 ton) hour bell, cast on 10 April 1856 in Stockton-on-Tees by George Mears. The bell was never officially named, but the legend on it records that the commissioner of works, Sir Benjamin Hall, was responsible for the order; another theory is that the bell may have been named after heavyweight boxer Benjamin Caunt who was popular at the time. There's also a story that the bell was to be called "Victoria" in honour of Queen Victoria, but the ceremonial speeches went on so long that some joker shouted out "Oh, just call it Big Ben and have done with it!" and the name stuck.
The Great Bell in the Clock Tower is widely known as Big Ben.
The bell weighs 13.8 tonnes and was first rung in 1859
Other Bells
Along with the main bell, the belfry houses four-quarter bells that play the Westminster Quarters on the quarter hours. The four quarter bells are G sharp, F sharp, E, and B . They play a 20-chime sequence, 1-4 at quarter past, 5-12 at half past, 13-20 and 1-4 at quarter to, and 5-20 on the hour. Because the low bell (B) is struck twice in quick succession, there is not enough time to pull a hammer back, and it is supplied with two hammers on opposite sides of the bell.
Clock Face - External View
A 1.63 m (5 foot 4 inch) person has been inserted into the picture at correct scale. The hour hand is 9 feet (2.7 m) long and the minute hand is 14 feet (4.3 m) long.
Augustus Pugin designed the clock and dials. The clock faces are set in an iron framework 21 feet (7 metres) in diameter, supporting 576 pieces of opal glass, rather like a stained glass window. Some of the glass pieces may be removed for inspection of the hands. The surround of the dials is heavily gilded. At the base of each clock face in gilt letters is the Latin inscription 'DOMINE SALVAM FAC REGINAM NOSTRAM VICTORIAM PRIMAM' meaning 'O Lord, keep safe our Queen Victoria the First'.
The clock became operational on 7 September 1859.
The clock faces were once large enough to allow the Clock Tower to be the largest four-faced clock in the world, but have since been outdone by the Allen-Bradley Clock Tower in Milwaukee, Wisconsin. The builders of the Allen-Bradley Clock Tower did not add chimes to the clock, so the Great Clock of Westminster still holds the title of the "world's largest four-faced chiming clock." The clock mechanism itself was completed by 1854, but the tower was not fully constructed until four years later in 1858.
During World War II, the Palace of Westminster was hit by German bombing, destroying the House of Commons and causing damage to the tower's western clock face.
The clock became operational on 7 September 1859.
The clock faces were once large enough to allow the Clock Tower to be the largest four-faced clock in the world, but have since been outdone by the Allen-Bradley Clock Tower in Milwaukee, Wisconsin. The builders of the Allen-Bradley Clock Tower did not add chimes to the clock, so the Great Clock of Westminster still holds the title of the "world's largest four-faced chiming clock." The clock mechanism itself was completed by 1854, but the tower was not fully constructed until four years later in 1858.
During World War II, the Palace of Westminster was hit by German bombing, destroying the House of Commons and causing damage to the tower's western clock face.
The Face Of The Great Clock of Westminster
Clock Face - Internal View
The minute hands of the great clock are made of copper and the hour hands are made of gunmetal.
The numerals are about half a metre high and there are 312 panes of glass in each of the four faces.
The numerals are about half a metre high and there are 312 panes of glass in each of the four faces.
View Of The Clock Face From Inside The Clock Tower
Photography by Deryc Sands
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