The British Government, impressed with the necessity of finding the correct longitude at sea, had offered in 1713 very liberal rewards of ten, fifteen and twenty thousand pounds to anyone who could construct chronometers that would enable the position of a ship to be found within 60, 40 and 30 miles respectively.
In 1751 Harrison, after making sundry attempts, brought a watch to London which, when tested on a voyage from England to Jamaica and back, lost only 1 minute 53-1/2 seconds, and thus enabled the longitude to be found within eighteen miles.
He claimed the reward of £20,000, but only received sums on account from time to time, and it was after much agitation that he finally was paid in full in 1773.
Owing to the success of this timepiece and the subsequent discussions over the award, the inventor got the sobriquet of "Longitude Harrison."
The Irish Times, April 25th, 1931