About the middle of the seventeenth century, Huygens made his great improvement in clock-work, which produced many others from our own countrymen[1116]; the latest of which was the introduction of repeating watches, in the time of Charles II., who, as I have been informed by the late lord Bathurst, sent one of the first of these new inventions to Lewis XIV. The former of these kings was very curious with regard to these time-measurers; and I have been told by an old person of the trade, that watchmakers, particularly East, used to attend whilst he was playing at the Mall; a watch being often the stake.
But we have a much more curious anecdote of royal attention to watches in Dr. Derham’s Artificial Clock-maker (p. 107). Barlow had procured a patent, in concert with the Lord Chief Justice Allebone, for repeaters; but Quare making one at the same time upon ideas he had entertained before the patent was granted, James II. tried both, and giving the preference to Quare’s, it was notified in the gazette. In the succeeding reign, the reputation of the English work in this branch was such, that in the year 1698, an act passed, obliging the makers to put their names on watches, lest discreditable ones might be sold abroad for English[1117].
Letter on the pretended Watch of King Robert Bruce[1118].
You will remember that I formerly mentioned something to you in reference to the observations made by the Hon. Daines Barrington, on the earliest introduction of clocks, published in the Annual Register for 1779, under the article Antiquities, p. 133. According to your desire, I will communicate what circumstances come within my personal knowledge, about a watch that corresponds very much to one described by him as once the property of king Robert Bruce. I must be indulged, although in some particulars I cannot speak with absolute certainty, as so much time hath elapsed since the transaction I am going to relate.
Being early fond of anything ancient or uncommon, I used to purchase pieces of old coin from a goldsmith who wrought privately in Glasgow, and sometimes went about as a hawker. Having often asked him from the curiosity of a boy, if he had ever been at the castle of Clackmannan, or heard of any antiquities being found there, he told me that he had purchased from Mrs. Bruce, who is the only survivor of that ancient family in the direct line, an old watch, which was found in the castle, and had an inscription, bearing, that it belonged to king Robert Bruce. I immediately asked a sight of it; but he told me it was not at hand. He fixed a time for showing me this invaluable curiosity; but even then it could not be seen. My avidity produced many anxious calls, although by that time I began to suspect he meant to play upon me, especially as I did not think it altogether credible that Mrs. Bruce would sell such a relict of her family if she had ever had it in her possession. At length I was favoured with a sight of it. The watch, as far as I can recollect, almost entirely answered the one described. It had a ground of blue enamel. It had a horn above the dial-plate instead of a glass. The inscription was on the plate. But whether it was Robertus B. or Robertus Bruce, I cannot remember. The watch was very small and neat, and ran only, to the best of my knowledge, little more than twelve hours, at least not a complete day. The Hon. Mr. Barrington does not mention anything about this circumstance. It is about twelve years since I saw it. Whether there be any castle in Fife properly called Bruce castle, I know not; but the castle of Clackmannan hath always been the residence of the eldest branch of the family; and although the town in which it stands now gives name to a small county, yet in former times, and still in common language, that whole district receives the name of Fife, as distinguishing it from the county on the other side of the firths of Forth and Tay. The first thing that occurred to me about the watch itself, was in regard to the inscription. Observing that all the coins of king Robert’s age bore Saxon characters, I could not believe the inscription to be genuine, because the characters were not properly Saxon, but a kind of rugged Roman, or rather Italic characters, like those commonly engraved, but evidently done very coarsely, to favour the imposition. He valued it at 1l. 10s., but I would have nothing to do with it. The first time I had an opportunity of seeing Mrs. Bruce of Clackmannan, after this, I asked her if such a watch had ever been found. She told me that she never so much as heard of any such thing. This confirmed the justness of my suspicion.
I paid no further regard to this story till about seven years ago, when I received a letter from a friend, informing me, that a brother of his in London, who had a taste for antiquity, had desired him, if possible, to procure some intelligence from Glasgow about a watch, said to be king Robert Bruce’s, which had thence found its way to London, and was there making a great noise among the antiquaries. I then applied to my former goldsmith, who was then in a more respectable way, and mentioned the old story. He immediately fell a-laughing, and told me, that he did it merely for a piece of diversion, and thought the story would take with me, as I had been often asking about the place. He said that it was an old watch brought from America; that, to get some sport with my credulity, he had engraved the inscription upon it in a rough, antiquated-like form; that he had afterwards sold it for two guineas; he had learned that it was next sold for five, and had never more heard of it.
However early the invention of clocks might be, I am greatly mistaken if any authentic documents can be produced of the art of making pocket-watches being discovered so early as the beginning of the fourteenth century. Lord Kaimes, somewhere in his Sketches of Man, asserts, that the first watch was made in Germany, so far as I can remember, near the close of the fifteenth century[1119]. If any watch had been made so early as R. Bruce’s time, it is most likely the inscription would have been in Saxon characters, as not only the money both of Scotland and England, but of Germany, in that age, bears a character either Saxon, or greatly resembling it.
Whatever ardour one feels for anything that bears the genuine marks of antiquity, it is certainly a debt he owes to those who have the same taste, to contribute anything in his power that may prevent impositions, to which antiquaries are abundantly subject, through the low humour or avarice of others; or that may tend to confirm a fact by proper comparison and minute investigation of circumstances. Besides, this is of greater moment than settling the genuineness of a coin, or many other things of the same nature, because it involves in it the date of a very important discovery. It doth not merely refer to the history of an individual, or even of one nation, but to the history of man. It respects the progress of the arts; and an anachronism here is of considerable importance, because, being established upon a supposed fact, it becomes a precedent for writers in future ages.
[The time and place at which watches were first made similar to those now in use, are not positively determined. The first step towards its accomplishment must have consisted in making a mainspring the source of motion instead of a weight[1120]. The invention of the fusee speedily followed the mainspring, and without it the former would be useless, in consequence of its tension varying according to the size of its coil. In the time of Elizabeth a watch was a very different kind of instrument to one of the present day. As regards size, it closely resembled one of our common dessert-plates. Before Dr. Hooke’s improvement, the performance of watches was so very irregular that they were considered as serving only to give the time for a few hours, and this in rather a random kind of way. The invention by Dr. Hooke of a spiral spring applied to the arbor of the balance, by which means effects were produced on its vibrations similar to the action of gravity on the pendulum of a clock, was perhaps of more importance than any improvement which has been subsequently made. Watches were common in France before 1544, as in that year the corporation of master clockmakers in Paris had a statute enacted to ensure to themselves the exclusive privilege of making and causing to be made clocks and watches, large or small, within the precincts of that city. The anchor-escapement was invented by Clement, a London clockmaker, in 1680. Previously to 1790, two kinds of watches were made, the vertical and the horizontal. The former was first used in clocks, then in watches. The horizontal was invented in 1724, by George Graham, F.R.S. (an apprentice of the renowned Tompion), to whom we are indebted for two of the most valuable improvements in clocks which have ever been made, viz. the dead-beat, or Graham escapement[1121], as it is called, and the mercurial compensation pendulum. The best proof that can be adduced of the importance of these inventions is, that they still continue to be employed in all their early simplicity, in the construction of the best astronomical clocks of the present day. Graham’s horizontal escapement is still extensively employed in the Swiss and Geneva watches, but in the better sort of those of English manufacture, it has been superseded by the duplex, and recently by the lever, which is nothing more than the application of Graham’s dead-beat escapement to the watch, though patents have been taken out by various persons who have claimed the invention. The most remarkable inventions of this period were those of Harrison, consisting of his gridiron pendulum, the going fusee, the compensation curb, and the remontoir escapement. In 1736, he appears to have completed his longitude watch, and received from the Royal Society their gold medal; he ultimately received the government reward of £20,000, together with other sums from the Board of Longitude and the Honourable East India Company. Notwithstanding his application of the compensation curb to the watch, it was still a subject of inquiry, and by many persons it was thought that the expansion and contraction of the metal, of which the spring is composed, was the source of variation in the equality of its motion under changes of temperature; but the consideration that the change of rate in the clock, with a seconds pendulum, in passing from the winter to the summer temperature, amounted only to about twenty seconds, while that of the watch exceeded six minutes and a half under similar circumstances, led careful observers to infer that some other cause must be assigned for the anomaly, and the loss of elasticity of the balance-spring by heat began to be suspected, as appears by the following passage in the Prize Essay of Daniel Bernoulli, read before the French Academy:—“I must not omit (said this celebrated geometrician) a circumstance which may be prejudicial to balance watches; it is, that experimental philosophers pretend to have remarked that certain changes of elastic force uniformly follow changes of temperature. If that be the case, the spring can never uniformly govern the balance.” That which Bernoulli only conjectured, was in 1773 established as a matter of certainty, and the amount in loss of time due to each of the three conjointly operating causes determined by Berthoud to be,—loss by expansion of the balance, 62 seconds; loss by elongation of the balance-spring, 19 seconds; and loss by the diminution of the spring’s elastic force by heat, 312 seconds, by an increase of 60° of heat of Fahrenheit’s scale. We have previously observed that Harrison’s compensation curb was inefficient, as besides other defects, it interfered too much with the isochronism of the balance-spring, as the inventor himself was candid enough to confess that the balance, balance-spring, and compensation curb, were not contemporaneously affected by changes of temperature, since small pieces of metal were sooner affected than large, and those in motion before those at rest. Whence he was led to conclude, that if the provision for heat and cold could properly reside in the balance itself, as was the case with his gridiron pendulum clocks, the time-piece might be made much more perfect. This ingenuous observation is the more to Harrison’s credit, as it was certainly his interest to conceal such a suggestion, being at that time a candidate for the government reward. The complexity of Harrison’s timekeeper and the high price, £400, demanded by Kendall to make them after that model, still left the timekeeper to be discovered that would come within the means of purchase of private individuals: for admirably as Harrison had succeeded in the construction of those which had procured him his reward, and great as were the talents of his assistant Larcum Kendall, yet for practical purposes, there needed an instrument of greater simplicity, and to John Arnold we are indebted for its invention.
Arnold is also celebrated for the manufacture of the smallest repeating-watch ever known: it was made for his majesty George III., to whom it was presented on his birthday, the 4th of June 1764. Although less than six-tenths of an inch in diameter, it was perfect in all its parts, repeated the hours, quarters and half-quarters, and contained the first ruby cylinder ever made. Indeed so novel was the construction of this little specimen of mechanical skill, that he was forced not only to form the design and execute the work himself, but also to manufacture the greater part of the tools employed in its construction. It is minutely described in Rees’s Cyclopædia, and also in the Sporting Magazine of that time, in which latter work it is correctly stated to be of the size of a silver twopence, and its weight that of a sixpence. The King was so much pleased with this rare specimen of mechanical skill, that he presented Mr. Arnold with 500 guineas; and the Emperor of Russia afterwards offered Mr. Arnold 1000 guineas for a duplicate of it, which he declined.