The Expansion Of Great Britain Essay Research

The Expansion Of Great Britain Essay, Research Paper

Many opinions exist regarding the origin of Great Britain s expansion in the 1700 s. Many people believe that the expansion was a result of the pursuit of trade routes to foreign countries. Others believe that it was driven by the patriotic hearts of British citizens; volunteering for government jobs to better their country. These theories, while not totally devoid of logical thought and true fact, are based on facts which, in turn, relied on the invention of an accurate clock. The expansion of the British Empire in the 1700 s relied more on the invention of an accurate clock than all the social, economical, and financial reasons combined.

The reason for this is simple: For every 15. that one travels Eastward, the local time moves one hour ahead. Similarly, travelling West, the local time moves back one hour for every 15. of longitude. Therefore, if we know the local times at two points on Earth, we can use the difference between them to calculate how far apart those places are in longitude, East or West.(1) This idea was very important to sailors and navigators in the 17th Century. They could measure the local time, wherever they were, by observing the Sun, but navigation required that they also know the time at some reference point, eg. Greenwich, in order to calculate their longitude. Although accurate pendulum clocks existed in the 17th Century, the motions of a ship and changes in humidity and temperature would prevent such a clock from keeping accurate time at sea.(2)

Because of this, Great Britain s trade was confined to only those countries that could be reached by coastal sailing , or sailing along the coast of a body of land. This hampered Great Britain s attempt to build a more powerful economy, and it confined the British empire to expand only within the same parameters of its trading options. Therefore, the inability to calculate one s longitude at sea was a serious problem for Great Britain, and serious measures were taken to correct it.

King Charles II founded the Royal Observatory in 1675 to solve the problem of finding longitude at sea. If an accurate catalogue of the positions of the stars could be made, and the position of the Moon then measured accurately relative to the stars, the Moon’s motion could be used as a natural clock to calculate Greenwich Time. Sailors at sea could measure the Moon’s position relative to bright stars and use tables of the Moon’s position, compiled at the Royal Observatory, to calculate the time at Greenwich. This means of finding Longitude was known as the Lunar Distance Method.

In 1714, the British Government offered, by Act of Parliament, 20,000 for a solution which could provide longitude to within half-a-degree (2 minutes of time). The methods would be tested on a ship, sailing

and should prove to be reliable.

A body known as the Board of Longitude was set up to administer and judge the longitude prize. They received more than a few weird and wonderful suggestions. Like squaring the circle or inventing a perpetual motion machine, the phrase “finding the longitude” became a sort of catch-phrase for the pursuits of fools and lunatics. Many people believed that the problem simply could not be solved.

The longitude problem was eventually solved by a working class joiner from Lincolnshire with little formal education. John Harrison took on the scientific and academic establishment of his time and won the longitude prize through sheer determination and an extraordinary talent and technical insight.

Harrison was born in Foulby, near Wakefield, in Yorkshire in 1693 but his family moved to Barrow, in Lincolnshire, when he was quite young. His father was a carpenter and John followed in the family trade. He built his first longcase clock in 1713, at the age of 20. The mechanism was made entirely from wood, which was not a curious choice of material for a joiner. Three of Harrison’s early wooden clocks have survived; the first (1713) is in London, at the Worshipful Company of Clockmakers’ Collection in Guildhall;. the second (1715), is in the Science Museum; the third (1717) is at Nostell Priory in Yorkshire.

He married his first wife, Elizabeth, in 1718. She died just eight years later and he remarried within six months, to another Elizabeth.

During the latter part of his early career, he worked with his younger brother James. Their first major project was a revolutionary turret clock for the stables at Brocklesby Park, seat of the Pelham family. The clock was revolutionary because it required no lubrication. 18th century clock oils were particularly poor and one of the major causes of failure in clocks of the period. Rather than concentrating on improvements to the oil, Harrison designed a clock which didn’t need it. It was radical thinking of this sort that would be important later on, when he tackled the problem of designing a marine timekeeper.

During the mid-1720’s, John and James designed a series of remarkable precision longcase clocks, to see how far they could push the capabilities of the design. By inventing a pendulum rod made of alternate wires of brass and steel, Harrison eliminated the problem of the pendulum’s effective length increasing in warmer weather, slowing the clock. As a result, Harrison’s regulators from this period achieved an accuracy of one second in a month, a performance far exceeding the best London clocks of the day.

To solve the longitude problem, Harrison would have to devise a portable clock which kept time to the same accuracy as these precision regulators…

Constructed between 1730 and 1735, H1 is essentially, a portable version of Harrison’s precision wooden clocks. It is spring-driven and only runs for one day (the wooden clocks run for eight days). All of the moving parts are counterbalanced and controlled by springs so that, unlike a pendulum clock, H1 is independent of the direction of gravity. The linked balance mechanism also ensures that any change in motion which affects one of the balances is compensated for by the same effect on the other balance.

Harrison’s linked balance mechanism negates the effects of motion of the clock.

H1 was brought to London in 1735 and displayed to the scientific community. Harrison was beseiged by requests from both scientists and socialites to see the timekeeper.

In 1736, Harrison and his timekeeper travelled to Lisbon aboard the ship Centurion, as a test of the clock, and returned on the Orford. H1 performed well in the trial, keeping time accurately enough for Harrison to correct a misreading of the Orford’s longitude on the return voyage. However, Harrison did not ask for a second trial but, instead, requested financial assistance from the Board of Longitude to make a second marine timekeeper.

Larger and heavier than H1, H2 is of fundamentally the same design as H1. Harrison began work on H2 in 1737 but in 1740 realised a deficiency in its design and requested more money from the Board to work on a third timekeeper.

Harrison worked on his third timekeeper from 1740 to 1759. After 19 years of labour, it refused to reach the accuracy required by the Board of Longitude.

H3 incorporated two inventions of Harrison’s; a bimetallic strip, to compensate the balance spring for the effects of changes in temperature, and the caged roller bearing, the ultimate version of his anti-friction devices. Both of these inventions are used in a variety of machines nowadays.

Despite these innovations, work on H3 seemed to lead nowhere and its ultimate role was to convince Harrison that the solution to the longitude problem lay in an entirely different design.

In 1753, Harrison had commissioned John Jefferys, a London watchmaker, to make him a watch following Harrison’s own designs. The watch was intended for Harrison’s own personal use – to help with his astronomical observing and clock testing. Noone in the 1750’s thought of the pocket watch as a serious timekeeper. However, Harrison discovered with his new watch that if certain improvements were made, it had the potential to be an excellent timekeeper.

In 1755, as well as asking for continued support for the construction of H3, he asked the Board of Longitude for support

H4 is completely different from the other three timekeepers. Just 13cm in diameter and weighing 1.45kg, it looks like a very large pocket watch. Harrison’s son William set sail for the West Indies, with H4, aboard the ship Deptford on 18 November 1761. They arrived in Jamaica on 19 January 1762, where the watch was found to be only 5.1 seconds slow! It was a remarkable achievement but it would be some time before the Board of Longitude was sufficiently satisfied to award Harrison the prize.

A second trial of H4 was arranged and William departed for Barbados aboard the Tartar on 28 March 1764. As with the first trial, William used H4 to predict the ship’s arrival at Madeira with extraordinary accuracy. The watch’s error was computed to be 39.2 seconds over a voyage of 47 days, three times better than required to win the 20,000 longitude prize. He turned over his secrets and was eventually awarded the rest of the prize money, though the British parliament was very reluctant to hand it over.


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