These

afforded by the documents of the times. summaries, as they are called, are inserted by Hume, in the place of the speeches which the ancient historians were wont to put into the mouth of their leading men; and, interesting as they are, deserve no more credit, considered as the character of parties, or as accounts of what was really said, than it is usual to bestow on those elaborate harangues. There is much reason to believe that the historian began the reigns of the two first Stuarts with a sincere conviction that sufficient allowance had not been made for the peculiar situation of those princes. But his delinquencies are such, that this excuse must be of small avail in his defence. The majority of more than one generation in this country have derived their notions of English history almost exclusively from the pages of Hume; but so low has he fallen as a historical authority, that the persons who have read scarcely anything else, rarely show courage, or rather weakness, enough to make any appeal to him.

JOHN HARRISON was born in May, 1693, at Foulby, in Yorkshire. His father, who was a joiner, trained him from an early age to the same business; but he soon began to study machinery. He turned his attention to the mechanism of clocks; and to obviate the irregularities produced in their rate of going by variations of temperature, he invented the method of compensation, employed in what is now called the gridiron pendulum, before the year 1720. This contrivance consisted in constructing a pendulum with bars of different metals, having different rates of expansion so as to correct each other: it is described in all popular treatises on physics. By this means it is stated that he had, before the year above mentioned, constructed two clocks which agreed with each other within a second a month,

and one of which did not vary, on the whole, more than a minute in ten years.*

This success induced him to turn his attention to watches, or rather to time-keepers for naval purposes. It would be impossible without the help of plates to render intelligible the rise and progress of his methods, for which we must refer the reader to treatises on Horology. His first instrument was tried upon the Humber, in rough weather, and succeeded so well that he was recommended to carry it to London, for the inspection of the Commissioners of Longitude.

The question of the discovery of the longitude had been considered of national importance since the year 1714, when an Act was passed offering 10,000/., 15,000/., and 20,000l. for any method of discovering the longitude within 60, 40, or 30 miles respectively. In 1735 Harrison arrived in London with his time-piece, and showed it to several members of the Royal Society. He obtained a certificate of its goodness, signed by Halley, Smith, Bradley, Machin, and Graham, in consequence of which he was allowed to proceed with it to Lisbon, in a king's ship, in 1736. The watch was found to correct the ship's reckoning a degree and a half; and the Commissioners thereupon gave Harrison 500l., to enable him to proceed. He finished a second time-piece in 1739, and a third in 1758, each nearer to perfection than the former, and both abounding in ingenious contrivances to overcome the effects of temperature, and of the motion of a vessel at sea. In 1741 he obtained another certificate, signed by almost every name of eminence in English science of the time. In 1749 the gold medal of the Royal Society was awarded to him. In 1761, having then a fourth

• Folke's Address to the Royal Society, Nov. 30, 1749. VOL. III.

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time-piece in hand, but being convinced that the third was sufficiently correct to come within the limits of the act of parliament, he applied to the Commissioners for a trial of it. Accordingly, in 1761 (Nov. 18), his son, William Harrison, was sent in a king's ship to Jamaica with the watch, and returned to Portsmouth, March 26, 1762. On arrival at Port Royal, Jan. 19, 1762, the watch was found wrong only 5 seconds; and at its return, only 1 minute 54 seconds. This was sufficient to determine the longitude within 18 miles; and Harrison accordingly claimed 20,000l., in a petition to the House of Commons, presented early in 1763. The Commissioners had awarded him 15007., and promised 1000/. more after another voyage. Owing to some doubt as to the method of equal altitudes employed in finding the time at Port Royal, they do not appear to have been of opinion that the first voyage was conclusive. In 1763 an act passed, by which, firstly, no other person could become entitled to the reward until Harrison's claim was settled; and secondly, 5,000l. was awarded to him on his discovery of the structure of the instrument. But the Commissioners not agreeing about the payment, another voyage was resolved on, and Mr. William Harrison sailed again for Barbadoes, with Dr. Maskelyne, afterwards the Astronomer Royal. The result was yet more satisfactory than before; and in 1765 a new act was passed, awarding to Harrison the whole sum of 20,000l.: the first moiety upon the discovery of his construction; the second, so soon as it should be found that others could be made like it. In this act it is stated that the watch did not lose more than ten miles of the longitude. But Harrison had by this time been rendered unduly suspicious of the intentions of the Commissioners. He imagined that Dr. Maskelyne had treated him

unfairly, and was desirous of having no method of finding the longitude except that of lunar observations. An account of the subsequent proceedings, of which the following is an abstract, was printed in self-defence by the Commissioners :

May 28, 1765, Mr. Harrison's son informs the Commissioners that he is ready to deliver the drawings and explanations, and expects a certificate that he is entitled to receive the first moiety of the reward. The Commissioners are unanimously of opinion that verbal explanations and experiments, in the presence of such persons as they may appoint, will be necessary. May 30, Mr. Harrison attends in person, and consents to the additional explanation; and certain men of science, as well as watchmakers, are instructed to receive them. June 13, Mr. Harrison, being present, is informed that the Board is ready to fix a time to proceed, on which he denies ever having given his assent, and refers to a letter which he had delivered at the last meeting. The letter had not, says the Commissioners' Minute, been delivered, but had been left upon the table, unnoticed by any one. It was to the effect that Harrison was willing to give further verbal explanation, but requires to know to whom it must be given; "for," says he, "I will never attempt to explain it to the satisfaction of the Commissioners, and who they may appoint; nor will I ever come under the directions of men of theory." He further refuses to make any experimental exhibition, and ends by complaining of the usage he has received. He was then told by the Board that he would only be asked for experiments in cases where there were operations which could not be fully explained by words, such, for instance, as the tempering of the springs; on which he left the Board abruptly, declaring, "that he never would consent to it, as long as he had a drop of English blood in his