The Clock Tower, mostly known as Big Ben, anniversary: 150 years on Parliament's grounds.

BIG BEN

The Clock Tower seen today is not the first tower to be built in Parliament’s grounds. The original tower was built in 1288-90, during the reign of King Edward I, and located on the north side of New Palace Yard containing a bell and clock. The bell was first named 'Great Edward' and later 'Great Tom’; it then struck on the hour. A second tower replaced the original one in 1367. This was the first public chiming clock in England. By 1707, this tower had fallen into disrepair and was demolished. A sundial was put up in its place.
A terrible fire destroyed most of the Palace of Westminster in 1834. Architects were invited to submit their designs for the new Palace and a commission was set up to select the best. Out of 97 designs submitted, the architect Sir Charles Barry’s was successful. However, his winning design did not feature a clock tower. He added this to his design in 1836.
The construction of the Clock Tower began in September 1843. This is the iconic tower which stands today in the Houses of Parliament. The Clock Tower was built from the inside outwards, meaning that no scaffolding was visible to the outside world. Materials were transported by river. A winch lifted materials to the masons and bricklayers.
Officially, the Clock Tower’s bell is called the Great Bell though it is better known by the name 'Big Ben'. The name 'Big Ben' is often associated with the Clock Tower and the Great Clock as well as the Great Bell. It was to the Great Bell that the name originally was given.
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.

Dimensions

Dimensions: over 96 metres and 12 metres square
Steps to belfry: 334
Steps to lantern (the Ayrton Light): 393

Amount of stone used: 850 cubic metres
Amount of bricks used: 2600 cubic metres

Number of floors: 11

Locations of building materials:
Anston, Yorkshire
Caen, Normandy, France
Clipsham, Rutland (for restoration work in 1983-5)




Clock dials

Number of clock dials: 4
Clock dials diameter: 7m
Length of hour figures: 60cm
Clock dial frames: cast iron
Glass in each clock dial: 312 pieces of pot opal glass
Illumination of each dial: 28 energy efficient bulbs at 85 watt each
Lifetime of each energy efficient bulb: 60,000 hours



Minute hands

Material: copper sheet
Weight: 100kg, including counterweights
Length: 4.2m
Distance travelled by minute hands per year: equivalent of 190km



Hour hands

Material: gun metal
Weight: 300kg including counterweights
Length: 2.7m
The hour figure of 4 o’clock is shown by the Roman numeral IV, rather than the usual IIII on other clocks.



The pendulum bob

Pendulum bob weight: 203kg
Material: concentric tubes of steel and zinc













[Source: Parliament’s Big Ben's Web]