a watch. At length William Harrison set sail with this timekeeper
from Portsmouth for Jamaica, on November 18th, 1761, in the Deptford
man-of-war. The Deptford had forty-three ships in convoy, and arrived
at Jamaica on the 19th of January, 1762, three days before the Beaver,
another of His Majesty's ships-of-war, which had sailed from Portsmouth
ten days before the Deptford, but had lost her reckoning and been
deceived in her longitude, having trusted entirely to the log.
Harrison's timepiece had corrected the log of the Deptford to the
extent of three degrees of longitude, whilst several of the ships in
the fleet lost as much as five degrees! This shows the haphazard way
in which navigation was conducted previous to the invention of the
marine chronometer.

When the Deptford arrived at Port Royal, Jamaica, the timekeeper was
found to be only five and one tenth seconds in error; and during the
voyage of four months, on its return to Portsmouth on March 26th, 1762,
it was found (after allowing for the rate of gain or loss) to have
erred only one minute fifty-four and a half seconds. In the latitude
of Portsmouth this only amounted to eighteen geographical miles,
whereas the Act had awarded that the prize should be given where the
longitude was determined within the distance of thirty geographical
miles. One would have thought that Harrison was now clearly entitled
to his reward of 20,000L.

Not at all! The delays interposed by Government are long and tedious,
and sometimes insufferable. Harrison had accomplished more than was
needful to obtain the highest reward which the Board of Longitude had
publicly offered. But they would not certify that he had won the
prize. On the contrary, they started numerous objections, and
continued for years to subject him to vexatious delays and
disappointments. They pleaded that the previous determination of the
longitude of Jamaica by astronomical observation was unsatisfactory;
that there was no proof of the chronometer having maintained a uniform
rate during the voyage; and on the 17th of August, 1762, they passed a
resolution, stating that they "were of opinion that the experiments
made of the watch had not been sufficient to determine the longitude at
sea."

It was accordingly necessary for Harrison to petition Parliament on the
subject. Three reigns had come and gone since the Act of Parliament
offering the reward had been passed. Anne had died; George I. and
George