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by Madeira ne voyages of
Pursuant to this request, observations of equal altitudes were taken at Portfmouth by Mr. Robertson, master of the Royal Academy, and the warch was set to the true time of that place; and on the 18th of November 1761, Mr. Harrison failed from Portsmouth, for Jamaica, in the Deptford, commanded by captain Digges.
On the 8th of December, by obfervation, the Deptford was, in the latitude 35o. 17 N. and in the longitude by the watch 15o. 17 W. from Portsmouth ; but by the ship's reckoning only 13°. 50'. and most of the ship's company were so confident of 'their reckoning being right, that they wanted to steer more to the westward in order to make the island of Porto Santo, as they were in want of beer, and afraid of lofing time. The captain, however, though he offered to lay five to one that the ship was three days run too far to the eastward, refufed to alter his course, as Mr. Harrison affirmed, that if the above island was accurately taid down in the maps they muft fee it the next morning:
His prediction proved true; for at seven in the morning the isand appeared, upon which both the captain and crew were very thankful to Mr. Harrison for keeping the ship's reckoning by the watch, as otherwise they thould not have seen the island of Madeira at all.
During the voyage from Madeira to Jamaica, the time-piece corrected the errors of the log, when they were full as great as in the voyage from Portsmouth. On their arrival at Jamaica, it appeared that the difference of longitude as found by the timepiece, and calculated by the observations of the tranfit of Mercury, was only five seconds of time, which, at Jamaica is little more than a geographical mile.
After staying a few days on the island, Mr. Harrison failed for England in the Merlin Noop, and the weather during great part of their partage proved so very tempestuous that they were obliged to place the time-piece on the counter in order to avoid its being perpetually exposed to the sea-water. In this situation it suffered continual violent agitations, which could not fail of retarding its motion in fome degree, yet it was found that the time-piece during the whole voyage from Portsmouth till its return had loft only one minute fifty-four seconds and a half ; which in the latitude of Portsmouth amounts to about eighteen geographical miles, or minutes of a great circle, whereas the act requires no more than that it should come within the distance of thirty geographical miles.
But notwithstanding the accuracy with which the time was kept by the machine, some difficulties arose with regard to the longitude of Jamaica, which was said to be not Tufficiently known, notwithstanding it had been determined by accurate obfervations on a transit of Mercury over the fun on the 25th of
October O&tober 1743. Mr. Harrison, however, submitted to make a second experiment of the correctness of his time-keeper, by another vovage to the West-Indies; and the island of Barbadoes was fixed upon by the commiflioners of longitude for that purpose.
Accordingly Mr. Harrison carried his machine on board the Tartar at Spithead, and on the 8th of March 1764, fail d for Barbadoes. In their paffage to the Canaries they met with hard and contrary gales, eipecially in the Bay of Biscay. On che 18th of April, Mr. Harrison declared, that they were fortythree miles to the eastward of Porto Santo ; on which the captain (Sir John Lindley) Iteered directly for it, and at one the next morning they saw the island, which exactly agreed with the distance given by Mr. Harrison.
On the 13th of May they arrived at Barbadoes, Mr. Harrison having during the whole voyage declared how far they were distant from that ifland, according to the best accounts of its longitude. The day before they made the island he declared the distance, and the captain found his declaration to be true.
Soon after their return, Mr. Harrison prelented a memorial to the commisiioners of longitude, in answer to which they declared, they were unanimously of opinion, that the memorialist's time-keeper had kept its time with fufficient exactness, and without losing its longiiude in a voyage from Portimouth to Barbadoes, beyond the neareft limit required by the act of the twelfth of queen Anne; but even considerably within the same. They added, however, " that as Mr. Harrison had not made a
discovery of the principles upon which his faid time-keeper is • constructed, nor of the method of carrying those principles ? into execution, by means whereof other time-keepers might
be framed, of suficient correctness to find the longitude at o sea, within the limits required by the act, whereby the inven! tion might be adjudged practicable and useful in terms of the • said act, and agreeable to the true intent and meaning thereof; • they did not therefore think themselves authorised to grant any ' certificate to Mr. Harrison until lie has made a full and clear • discovery of the faid principles and method, and the fame shall
have been found practicable and useful to their satisfaction. • They however declared they were of opinion, that applica ' tion should be made to parliament for leave to pay to Mr. • Harrison, on his producing his time-keeper to certain perfons ' to be named by the commiffioners, and discovering to them • the principles and manner of making the same, so much • money as will make up the sums already advanced to him ( 10,000 bexclusive of what he has received on account of • improvias his rime-keeper; and moreover to pay him the re' mainder of the reward of 20,000 l, on proof being made to F 2
o their satisfaction that his method will be of common and gee • neral utility in finding the longitude at sea, within the nearest « limits required by the act of the 12th of queen Anne.'
Application was accordingly made to parliament and a bill in consequence of it was passed during the last session, for granting Mr. Harrison 10,000 1. for discovering the longitude by his time-piece, and 10,000 l. more if it should equally answer in a voyage to be made by way of trial to Hudson's Bay. But disputes have hitherto prevented Mr. Harrison from receiving the aboye reward.
It has indeed been said, that the instrument does not keep equal time, being considerably affected by heat and cold, and that Mr. Harrison, in order to determine the variations of his machine, has constantly had recourse to a thermometer. But we cannot help doubting the validity of this objection, because it appeared, that the instrument had lost only one minute fiftyfour seconds and a half during the whole passage to and from Jamaica, as we have already observed. And it must therefore surely be very absurd to suppose that the errors arising from heat and cold could so accurately correct each other, especially when it is remembered that the voyage to Jamaica was in December, and consequently the ship must pass from extream cold to extream heat; whereas the voyage home was four months after, and therefore at a time when the weather was very different with regard to heat and cold. To which if we add the finding the Madeiras, and other islands during the passage to Jamaica, it seems hardly possible to doubt that the machine kept equal time during the whole voyage. . ..
It must after all be admitted, however, that even fuppofing Mr. Harrison's machine sufficiently exact, it is possible that it may not entitle him to the reward of 20,000 l. above-mentioned. For, if its construction be of fo nice and complicated a nature, as not to admit of its being of common and general utility at sea, his method certainly does not come within the intent and meaning of the act by which that reward is granted. The instrument can be of little use, if it requires the constant attendance of an artist of equal experience and ingenuity with the inventor. On the other-hand, it is prefumed the Commissioners of the Lon-' gitude do not expect that Mr. Harrison's machine should come as cheap, or be as little liable to accidents, as the common forestaves, and compass-boxes that are fold at the Ship-chandlers.' Hence we conceive that the difference between Mr. Harrison and the Commisioners might be easily adjusted, if they could agree about the construction of the words common and general utility.
Minutes of the Proceedings of the Commissioners appointed by Art of
Parliament for the Discovery of the Longitude at Sea, at their Meetings on the 25th, 28th, and 30th of May, and 13th of June, 1765, with respect to carrying into Execution fo much of an Aat passed in the last Sessions of Parliament, as relates to the giving Mr. John Harrison a Reward, upon his making a Discovery of the Principles of his Watch er Time-keeper. 4to. 6d.
Billingsley. M H ESE minutes relate to the difference between the
1 Commissioners of Longitude, and Mr. Harrison; and the following are the principal circumstances.
At a meeting at the Admiralty on Tuesday the 28th of May, 1765, the act passed in the last session of parliament for explaining and amending those of the 12th of Queen Anne, and 26th of George II. was read : after which the board went into the consideration of proper means for carrying the said act into execution; and having discoursed some time upon that part of it which relates to giving a reward to Mr. John Harrison, upon his discovering the principles of his watch or time-keeper, his fon, who was attending, was desired to inform the board, in what manner his father proposes to discover the said principles. He answered, that he was commissioned by him to deliver to the board the identical drawings from which his faid watch or timekeeper was made, with explanations thereof in writing; and that his father expects that the Commissioners will, upon receipt of the said drawings and explanations, give him a çeitificate to enable him to receive the first reward directed to be paid him by the above-mentioned act ; and that he is not authorized by his father to offer any other mode of discovery. He then withdrew.
The board then took into consideration the method of difcovery proposed by Mr. Harrison, and being unanimously of opinion, that drawings and written explanations alone, will not be a fufficient and satisfactory discovery of the principles of the said warch or time-keeper, agreeable to the before-mentioned act; Refolved, That Mr. Harrison be acquainted, that the Commissioners do expect his compliance with what is undermentioned, before they can give him the certificate he requires,
1. That he shall discover fully, by drawings and a written explanation, the principles upon which his laid watch is constructed, and deliver the same to this board, upon oath.
2. That he shall give a farther explanation by word of mouth, and experimental exhibitions where judged 'necesary, of the said principles, and of every thing relative to the construction of she laid waich; producing the same; taking it to picces ; aud F3
answering, upon oath, to every question proposed by the board, and such persons as may be appointed by them for the examination thereof.
3. That he is to make over the property of the three several timekeepers, and the watch, when he fall receive his certificate.
Mr. Harrison's fon was then called in, and these resolutions having been read to him, and a copy given him to shew to his father, he withdrew. • At a meting at the Admiralty on Thursday the 30th of May, 1765, Mr. John Harrison was called in, (together with his son) and discoursed with concerning the method proposed for the discovery of the principles of his watch or time-keeper ; and consented to do it agreeable to the resolutions of the last board.
The board then took into consideration the nomination of proper persons to be prefent when the discovery shall be made : And, after some time spent therein, Mr. Harrison and his son were again called in; and some persons, who were named by the Commissioners, having been objected to by them, the board came to the following resolutions, which were agreed to by Mr. Harrison, viz.
That, in addition to such of the Commiffioners who shall chuse to be present, three gentlemen skilled in mechanicks, and three watchmakeis, bę appointed to attend when the abovementioned discovery shall be made,
Refolved, That it be an instruction to such of the above-mentioned * gentlemen and watchmakers, as may be inclined to attend, to meet Mr. Harriíon as soon as possible, and to continue their meetings with him without interruption : And that they be enjoined not to make any discovery of the principles of the watch to any but the board, without leave of the Commisfiöners.
AT a meeting at the Admiralty on Thursday the 13th of June, 1765,
the Admiral y..
orbes, Admirals of the B!ue, Sir George Pocock,
m with as
* They are named in the minutes ; but ve have omitted them in this ahira?,