JOHN HARRISON AND THE FINDING OF LONGITUDE
Longitude is one of the co-ordinates given around the globe to help pin-point the location of a given place. The longitude planes from pole to pole lengthways. Before the technology of the modern world made calculating earth positions a simple task, the longitude posed the greatest of sea-going problems and became the subject of scientific and astronomical debate in the early eighteenth century. Ships could easily lose themselves by not being able to calculate the longitude and it has also caused many sea-going disasters.
In October 1707, the fleet of Admiral Sir Clowdisley Shovell were wrecked off the Scilly through not being able to gauge the correct longitude position of the fleet. Over two thousand men, including Shovell, were lost. This brought the subject to the fore and in July 1714, Parliament passed the Longitude Act. This convened a Board of Longitude to examine the problem and set up a £20,000 prize for the person who could invent a means of finding longitude to an accuracy of 30 miles after a six week voyage to the West Indies. It also made minor awards for discoveries and improvements to the general problem. The Board consisted of the Astronomer Royal, the President of the Royal Society, First Lord of the Admiralty, Speaker of the House of Commons, the First Commissioner of the Navy Board and three professors of mathematics from Oxford and Cambridge.
One method that was examined was the finding of longitude by astronomical means. The Astronomer Royal, Nevil Maskelyne thought that lunar tables charting lunar and star positions would be the answer to the problem. He resolutely rejected the possibility that a mechanical device could find solution to the longitude problem. This was to cause much anger and bitterness between himself and John Harrison, the man who produced the chronometer that finally solved the problem.
John Harrison was born in Foulby, Yorkshire on 24th March 1693. He was the eldest son of a carpenter and joiner, serving Sir Rowland Winn of Nostell Priory. Harrison received only a limited education but had a keen interest in machinery. He was employed on an estate in Lincolnshire and developed, with his brother, a series of clocks that kept very accurate time. In 1715, they developed an eight day clock, using wooden wheels. Later, in 1726, Harrison developed a grid-iron pendulum to avoid problems in timekeeping due to variations in temperature. He also invented a recoil escapement which meant that parts of the clock did not need to be oiled. In August 1718, he married Elizabeth Barrel and had a son, John born the following year. Seven years later, she died. Not long after, he married for the second time, to Elizabeth Scott and had another son, William and a daughter, Elizabeth. His first son, John, died at the age of 18 and William helped his father towards winning the prize.
The prize offered by the Board of Longitude was a tempting one for Harrison and he set out to make a sea-going timekeeper that could keep accurate time to claim the prize. It became his life-long work. The idea was to be able to compare local time to that of the pre-determined Greenwich time (which the timekeeper or chronometer would be set to), and thus find the longitudinal position of the ship.
In 1735, Harrison completed the first of his timepieces. It was made of brass and wood and weighed 72lbs. The chronometer was sent on a voyage to Lisbon to trial its accuracy. On its return, he was awarded £500 from the Board as a minor discovery. Harrison continued to improve his design and completed a second timepiece in 1739. This was less cumbersome than his previous clock. He continued to improve the design and his third timepiece, completed in 1749 was awarded the Copley Medal of the Royal Society.
His fourth timepiece, in the form of a pocket watch, was completed in 1759, and was the one with which Harrison intended to claim the prize. It was taken on board HMS Deptford for a voyage from Portsmouth to Jamaica and his son, William, accompanied it, to ensure that it was wound daily. The ship left in November 1761 and arrived in Jamaica on 26th March 1762. On arrival, the clock was checked and found to be 1 minute and 54 seconds out, a matter of 18 geographical miles. Harrison had succeeded and went to claim his prize.
Maskelyne, however, refused to accept the mechanical device, and being a more educated man than Harrison, was able to persuade the Board not to award the prize. Harrison then petitioned Parliament, who passed an Act specifically authorising £5000 to be awarded to him. Harrison was still unsatisfied - he felt he should have the whole prize as he had fulfilled the criteria of the Board. To show that it was no fluke, William again took the timepiece on another voyage to Barbados in 1764. This time the timepiece was accurate within 10 miles, even better than before. Still the Board refused to award the main prize although admitting that he had proved that the clock was effective. Parliament again intervened. It passed another Act to award £10000 on condition that Harrison explained the principles of the chronometer in full and that, if it could be replicated and work effectively by other craftsmen, the remainder of the prize would be awarded. Harrison was bitter at the way he was being treated, but agreed to the conditions. An exact copy of the his fourth timepiece (known as H4) was made by Larcum Kendal and was taken on Captain James Cook's second voyage between 1772-1774.
In the meantime, he made a fifth timepiece. William wrote to George III, whose interest in science was well known and had his own observatory in Richmond, to ask if he would care to observe and judge the timepiece for himself. The King took it to Richmond and was well pleased with the accuracy it maintained. In 1773, he appealed directly to the Prime Minister, Lord North on Harrison's behalf. In June 1773, Harrison was awarded £8750, totalling in effect the prize money offered. However, the Board were careful to point out that it was not the prize, but merely a bounty awarded by Parliament. A new Act, repealing the previous one, set out new strict conditions for the award of the prize money was passed - duplicate entries were required, they had to undergo a full year's trial at Greenwich and two voyages around Britain (one eastward and one westward), followed by a long distance voyage (destination stated by the Board) and followed by a year's post-voyage observation at Greenwich. The prize money was never claimed!
On Cook's return, Harrison felt his efforts had been totally vindicated as Cook extolled the virtues of the timepiece, and Cook had been able to make the first, accurate charts of the South Sea Islands. He was so pleased with the effectiveness of the chronometer, that he took it with him on his third and final voyage.
John Harrison died on his 83rd birthday on 24 March 1776 at Red Lion Square, London. He was buried in a vault in Hampstead church. A tomb was later erected by his son, William. In 1879, the London Company of Clockmakers reconstructed it as a mark of respect - even though Harrison had not been a member. His wife, Elizabeth, died a year later and William died in 1815.
The Longitude Act 1773 was repealed in 1828 and the Board of Longitude was disbanded. Although the main prize was never actually awarded, to all intents and purposes, Harrison had been the main winner. In total, the Board had made disbursements of £100,000 in the course of its life, the last being in 1815. After this, the problem of longitude had been solved and disasters, such as that that happened to Shovell's fleet, were no longer possible.
© Royal Naval Museum Library, 2004
The information contained in this INFORMATION SHEET is correct as far as we are able to ascertain from our sources. It is not intended to be an exhaustive or complete history of the subject. Please contact the library for a bibliography of further reading materials, if available.