This watch has since then obtained an extensive historical reputation, and it is preserved in the archives of the Clockmakers' Company as one of their most valuable treasures, for it is the earliest known English jewelled watch, and is the identical instrument produced before the House of Commons Committee, as evidence to upset, and which did upset, poor Facio's[ 59] claim for an extension of patent. Alas, for ancient reputations, it has been but recently discovered that Huggeford's watch was but a fraud, and that the jewel on the cock which deceived the Parliamentary Committee into supposing that Ignatius Huggeford, an Englishman, had applied jewels to watches long before Facio had been heard of, has nothing to do with the working of the watch. The jewel has been merely stuck on, just in the place where a jewel should be;[ 60] but as it is only fixed to the surface of the brass and no pivot plays in the jewel, it may be averred that the amethyst has no more to do with the movement of the watch than the silver ornaments on the watch-case. It is clear by the words in Facio's petition that his application of jewelling to watches was not merely done with the idea of ornamenting them,—in that there would have been no novelty,—and it seems probable that the amethyst would have been placed upon the face of the watch if the object of inserting it anywhere had simply been ornamentation; to speak plainly, none other than a fraudulent purpose could be served by its being placed where it is. It is, we fear, not impossible that the jewel was placed there at the instance of some of the members of the Clockmakers' Company, who, being perhaps jealous of the foreign invention, and fearful of its effects upon their own private trade, were still unable to prevent the grant of a patent, in May, 1703, for fourteen years to the inventor. But by December of that year, when application was made for the extension of the patent, they had had time to consider affairs and to prepare their opposition. We may believe this watch to have been Ignatius Huggeford's, and to have been all that it was sworn to be by the members of that Company, but, when we remark that neither is any mention whatever made by them, nor, as far as it appears, any question asked of them before the Parliamentary Committee as to the[ 61] jewel being upon the cock during the whole of the time of its being in their possession, we cannot but arrive at the conclusion that the jewel was placed upon Huggeford's old watch—the date of which could be shown—at the order of some of the members of the Clockmakers' Company with the purpose of defeating the patent, and that the Committee of the House of Commons were not as careful as they ought to have been in inspecting the jewel, for if they had, they must have seen the want of connexion between the amethyst and the pivot, which, it was pretended, was working in it. The probability is that at this time our English watch-makers scarcely knew how to apply a jewel, or otherwise they would have inserted the pivot in a proper manner. The story is anyhow a very extraordinary one, for, supposing the Clockmakers' Company to be innocent of conspiracy on the subject, it must have been a miraculously curious whim which possessed old Huggeford to insert a jewel as an ornament in a place where it would not be seen, and still more wonderful that it should, sham as it was, be placed exactly where it should suit the purpose of after-litigation. Of course there can be no imputation arising out of this incident to affect the members of the Clockmakers' Company of the present time, for they are no more answerable for what was done above a century and a half ago than the Parliament of to-day is to be blamed for allowing the execution[ 62] of Charles I., or for enacting the laws which led to the loss of our American colonies.

After the invention of jewels for watches came a still more important discovery.

Since 1530, when Gemma Frisius first proposed to ascertain the relative longitude of any place or ship at sea, by means of an horological machine for indicating the time of the first meridian, the subject had excited the attention of most of our philosophers, but unavailingly, as there was then no chronometrical instrument, upon which reliance might safely be placed. Huygens, in 1664, had contrived a time-piece actuated by a spring and regulated by a pendulum, but the pendulum was affected by the tossing of the ship, and by a change of temperature, as well as being subject, as was afterwards discovered, to a variation in weight depending on the parallel of latitude. The Academy of Sciences at Paris proposed, in 1720, a reward for the best paper in reply to the question:—'What is the most perfect method of preserving on the sea the equable motion of a pendulum?' The reward was given to a Dutchman named Massy, but his plan was not carried out. An English watch-maker named Henry Sully happened to be about this time in Paris directing a large manufactory of chronometers, and he presented the French Academy with a marine time-keeper of superior construction to the time-pieces of that period, and accompanied his gift by a memoir[ 63] describing it. Whilst still engaged in the study of his art, Sully, who was a clever man, unfortunately died, and the opportunity of advance seemed to have passed away.

About this time Graham invented the Mercurial Compensation pendulum, which consisted of a glass or iron jar filled with quicksilver and fixed to the end of the pendulum rod, which, when heat lengthened the rod, expanded simultaneously the quicksilver, and made the centre of oscillation to continue at the same distance from the point of suspension. He afterwards conceived a notion, which John Harrison subsequently worked out, of making a compensation pendulum (or a pendulum that should in itself contain the power of equalizing its own action, whatever the change of temperature), forming it of various metals. In 1726 Harrison invented what is called the gridiron pendulum, composed of nine rods, five of steel and four of brass, which are so arranged that those which expand most are counteracted upon by those of less expansion. These two compensation pendulums, the gridiron and mercurial, are still in use, and with slight improvements are found to keep to time very accurately.

The period had now arrived for the making of marine time-keepers sufficiently accurate for nautical use, and styled chronometers because they are most accurate time-measurers. Their value to navigators, and the immense impetus which would[ 64] by such instruments be given to the science of navigation, had long been foreseen, but there were many great difficulties in the way of obtaining a perfect chronometer. The sailor, before the invention of this instrument, could ascertain the latitude of his ship at sea, by observation of the fixed stars. Supposing these stars to have first appeared to him in the zenith, and at his next observation to be one, two, or three degrees south of the zenith, he would know that he had sailed just so many degrees north of the place in which he first observed them. It was not, however, so easy for him to compute longitudes, because the diurnal revolution of the earth causes each meridian to pass successively under the same stars. It was necessary to have an accurate time-keeper, and to set it carefully to the solar time of some port in the kingdom, whose longitude was well known. The time-piece might then be carried out in a vessel sailing abroad, and the computations made by means of it would prove most wonderfully exact and important. By simply observing the moment at which the sun reached his meridian, when of course it would be 12 o'clock at noon, solar time, and then noting the difference between the solar time thus ascertained and the time of the chronometer, the mariner would be able by calculating 15 degrees to one hour of time, or 15 geographical miles to one minute, to make out his longitude. For example, if the time[ 65]-piece had been set to time at the meridian of Greenwich observatory, and if it be one o'clock by the time-piece when it is mid-day, or meridian by the sun, then the place in which the longitude is taken must be in long. 15 degrees east of the meridian of Greenwich, and if it be eleven o'clock by the chronometer when the sun attains his meridian, then the place must be in long. 15 degrees west of the meridian of Greenwich. It is not indispensably necessary, that every chronometer used for maritime purposes should keep time exactly with that of the Greenwich observatory, or of any other instrument of known excellence, provided always that its rate as seamen call it, or the daily loss or gain of the chronometer, is well ascertained, and so may be computed in the calculations to be made. The indispensable requisite of a chronometer, however, is that the daily loss or gain shall not vary materially from itself at different periods, or under the changes of temperature of different climates, and these qualities being found in an instrument of any shape or make, constitute a marine chronometer.