arrangement remained the same. This second machine was finished

in 1739. It was more simple in its arrangement, and less
cumbrous in its dimensions. It answered even better than the

first, and though it was not tried at sea its motions were
sufficiently exact for finding the longitude within the nearest

limits proposed by Act of Parliament.
Not satisfied with his two machines, Harrison proceeded to make a

third. This was of an improved construction" target="_blank" title="n.建设；修建；结构">construction, and occupied still
less space, the whole of the machine and its apparatus standing

upon an area of only four square feet. It was in such
forwardness in January, 1741, that it was exhibited before the

Royal Society, and twelve of the most prominent members signed a
certificate of "its great and excellent use, as well for

determining the longitude at sea as for correcting the charts of
the coasts." The testimonial concluded: "We do recommend Mr.

Harrison to the favour of the Commissioners appointed by Act of
Parliament as a person highly deserving of such further

encouragement and assistance as they shall judge proper and
sufficient to finish his third machine." The Commissioners

granted him a further sum of 500L. Harrison was already reduced
to necessitous circumstances by his continuousapplication to the

improvement of the timekeepers. He had also got into debt, and
required further assistance to enable him to proceed with their

construction" target="_blank" title="n.建设；修建；结构">construction; but the Commissioners would only help him by
driblets.

Although Harrison had promised that the third machine would be
ready for trial on August 1, 1743, it was not finished for some

years later. In June, 1746, we find him again appearing before
the Board, asking for further assistance. While proceeding with

his work he found it necessary to add a new spring, "having spent
much time and thought in tempering them." Another 500L. was

voted to enable him to pay his debts, to maintain himself and
family, and to complete his chronometer.

Three years later he exhibited his third machine to the Royal
Society, and on the 30th of November, 1749, he was awarded the

Gold Medal for the year. In presenting it, Mr. Folkes, the
President, said to Mr. Harrison, "I do here, by the authority and

in the name of the Royal Society of London for the improving of
natural knowledge, present you with this small but faithful token

of their regard and esteem. I do, in their name congratulate you
upon the successes you have already had, and I most sincerely

wish that all your future trials may in every way prove
answerable to these beginnings, and that the full accomplishment

of your great undertaking may at last be crowned with all the
reputation and advantage to yourself that your warmest wishes may

suggest, and to which so many years so laudably and so diligently
spent in the improvement of those talents which God Almighty has

bestowed upon you, will so justlyentitle your constant and
unwearied perseverance."

Mr. Folkes, in his speech, spoke of Mr. Harrison as "one of the
most modest persons he had ever known. In speaking," he

continued, "of his own performances, he has assured me that, from
the immense number of diligent and accurate experiments he has

made, and from the severe tests to which he has in many ways put
his instrument, he expects he shall be able with sufficient

certainty, through all the greatest variety of seasons and the
most irregular motions of the sea, to keep time constantly,

without the variation of so much as three seconds in a week, --a
degree of exactness that is astonishing and even stupendous,

considering the immense number of difficulties, and those of very
different sorts, which the author of these inventions must have

had to encounter and struggle withal."
Although it is common enough now to make first-rate

chronometers-- sufficient to determine the longitude with almost
perfect accuracy in every clime of the world--it was very

different at that time, when Harrison was occupied with his
laborious experiments. Although he considered his third machine

to be the ne plus ultra of scientificmechanism, he nevertheless
proceeded to construct a fourth timepiece, in the form of a

pocket watch about five inches in diameter. He found the
principles which he had adopted in his larger machines applied

equally well in the smaller, and the performances of the last
surpassed his utmost expectations. But in the meantime, as his

third timekeeper was, in his opinion, sufficient to supply the
requirements of the Board of Longitude as respected the highest

reward offered, he applied to the Commissioners for leave to try
that instrument on board a royal ship to some port in the West

Indies, as directed by the statute of Queen Anne.
Though Harrison's third timekeeper was finished about the year

1758, it was not until March 12, 1761, that he received orders
for his son William to proceed to Portsmouth, and go on board the

Dorsetshire man-of-war, to proceed to Jamaica. But another
tedious delay occurred. The ship was ordered elsewhere, and

William Harrison, after remaining five months at Portsmouth,
returned to London. By this time, John Harrison had finished his

fourth timepiece--the small one, in the form of 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 l9th 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

previousdetermination 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 II. had reigned and died; and now, in the
reign of George III.--thirty-five years after Harrison had begun

his labours, and after he had constructed four several marine
chronometers, each of which was entitled to win the full