the very first near 20 seconds per day; a circumstance which is not my business to account for; but which, as it kept near mean Time in the Voyage to Barbadoes, seems to shew that the Watch cannot be taken to pieces and put together again without altering its Rate of going considerably, contrary to Mr. Harrison’s Assertions formerly.”

When I made the Discovery, upon Oath, of the Principles and Construction of the Watch, to six Gentlemen appointed by the Board of Longitude and to Mr. Maskelyne, (who insisted on having a Right to attend, as being a Commissioner) which Discovery was finished on the 22d Day of August, 1765, as appears by the annex’d Certificate,[2] the Watch then remained in my Hands, all taken to pieces: I little imagined the Board of Longitude would take it from me, as not conceiving any Use they could make of it; and having besides received Assurances from them, that they only wanted the formal Delivery of it, in compliance with the Terms of the new Law, without meaning to deprive me of the Use of it: I therefore went on making some experiments, and alter’d the Rate of its going, thereby to determine a Fact I wanted to be satisfied about. The Watch was under this Experiment the latter End of October, 1765, when upon receiving the Certificate for the Remainder of the first Moiety of my Reward, I was ordered to deliver it to the Board. My Son, attending with it, being asked if it was then as fit as before to ascertain the Longitude, reply’d in the Affirmative; for as I have before shewn, the Rate of its going, when once ascertained, does not prevent its keeping the Longitude. He was not asked the present Rate of its going, nor could he have answer’d with precision if he had, because we had not had Notice sufficient to determine that Point; but we did, at that Time, tell several of our Friends that it went about 18 or 19 Seconds a Day, fast, and we have at several Times since (without ever dreaming that this was to become a Point of public Discussion) had Occasion to mention the same Thing to several Members of Parliament, Commissioners of Longitude and other Gentlemen, insomuch that we did not believe any body was uninformed of it, who at all attended to the Business of the Longitude.

This may serve to account for the Circumstance which Mr. Maskelyne declares, it was none of his Business to account for, why the Watch was getting near 20 Seconds per Day; but as to his Inference, I must say it betrays the most absolute Ignorance of Mechanics, and of this Machine in particular, in which it is obvious (and for this Fact I appeal to the Watchmakers who saw it taken to Pieces) that its going at the same Rate when put together again, as before, depends (if none of the Parts are alter’d) upon nothing more complicated than putting a single Screw into the same Place from whence it was taken. Indeed this Passage, and the ignorant and puerile Remarks which Mr. Maskelyne has been suffer’d to prefix to my written Description of the Watch (to the Disgrace of this Country in those foreign Translations it has already undergone) bring strongly to my Remembrance an Observation made by some of the Gentlemen present at the Discovery, “that they wonder’d at his Patience in attending so long to a Subject he seem’d so totally unacquainted with.”

Mr. Maskelyne then proceeds to tell us of a Change that happen’d in the going of the Watch, and says, “this Change began in the Beginning of August, on the few and only hot Days we had last Summer, which yet were not extreme, the Thermometer within Doors having never risen above 73°. The Rest of the Summer in general was remarkably cool and temperate.” When I took this Watch to Pieces I informed Mr. Maskelyne and the other Gentlemen, that in trying any Experiments with it, in Respect to Heat and Cold, it would be proper that it should be so fixed that, as far as could be, the Heat should have an equal Influence on all Sides of it; and it is obvious that the Thermometer ought to have been kept in the same Box with it; but as this was not done, I apprehend the Effects of Heat mention’d above do not merit much Attention; and therefore shall only observe that the Watch was placed in a Box with a Glass in the Lid and another in one Side, in the Seat of a Window level with the lowest Pane of the Window, and exposed to the South East, whilst the Thermometer, which was to ascertain the Degree of Heat the Watch was exposed to, was placed in a shady Part of the Room: Now ’tis obvious that while the Air surrounding the Thermometer might be very temperate, there might, if the Sun shone upon it, be a heat in the Box, superior to what was ever felt in the open Air in any Part of the World; and perhaps greater than any human being could subsist in, and consequently improper, or at least unnecessary for this experiment.

Mr. Maskelyne next tells us of an irregularity which he says happened in cold Weather, and says, “However, it seems in general that the Frost must have been the cause of these irregularities, as well as of the Watch’s going so much slower in the Month of January, than it had gone before.” Mr. Maskelyne ought along with this, to have published what I told him when I explained it; that the Provision against the effects of Heat and Cold was not in this Machine extended to all Degrees; that I never had tryed it so low as the freezing Point, which according to the best Informations I have been able to procure is a Degree of Cold that never did exist between the Decks of a Ship at Sea, in any Climate yet explored by Mankind.

Mr. Maskelyne then comes to the Rate of its going in different Positions; and says, “It is obvious, these last-mentioned Trials of the Watch in a vertical Position could not be designed to shew how near it would go at Sea, where it can never obtain these Positions: the Intent of them is to prove how near Mr. Harrison’s Execution of his Watch comes up to his Principles, with respect to the making all the Arcs described by the balance, whether large or small, to be performed in the same Time, as Mr. Harrison asserts them to be.” Mr. Maskelyne here also might have had Candour enough to inform the Public, as I did him, that although the Watch was quite sufficient to answer the Purposes required of it in Navigation, and to fulfil what was prescribed by the Act of Queen Anne, yet it was far from being in a state of Perfection, as an universal exact Time-Keeper for every Purpose: I shew’d him and the rest of the Gentlemen the Reasons why the Machine then before them, would not go at the same Rate in such different Positions into which the Motion of a Ship could never put it; and whilst I explained to them those Imperfections in the particular Machine we were examining, I also in the clearest Manner I was able, pointed out the means of remedying them with certainty in others, which the Gentlemen skill’d in Mechanics seem’d perfectly to comprehend, and to be satisfied of the Truth which I again assert, that Watches made on my Principles will endure a much greater Motion and change of Position than they can ever be subject to in a Ship; and that they will not be affected by any Degree of Heat or Cold, in which a Man can live.

If any Thing was meant to be concluded with respect to me by this Experiment, either in Point of Property or of Reputation, common Justice would have required that I should have had an Opportunity of seeing the Facts ascertained; and when such a