n We owe to Julien Le Roy," continues Berthoud, " the suppressing of the bell in repeating watches, a change which has made these machines more simple, by rendering the movement larger, more solid, and less exposed to dust. These watches, which he called raised brass edges, are of a more handsome form. From the time of this celebrated artist, all the French repeater s have been made according to this model ; but in England, where repeating watches were invented, they make them for the most part with a bell ; and in Spain, this construction is still more preferred. In repeating watches without a bell, the hammers strike on brass pieces, either soldered or screwed to the case. Re peating watches with a bell have, also, as those without one, the property of being dumb, that is to say, of being able to make it repeat at pleasure, without the hammers being allowed to strike on the bell, or brass pieces." This effect is produced after the pendant is pushed in, by putting the point of the fme-finger on a small spring button, that comes through the case. Being a little press ed in, it opposes a piece against the hammers, which prc vents them from striking either a bell or the brass pieces inside of the case ; by which means the blows for hours and quarters are felt, though they cannot now be easily heard. This makes this kind of repeaters very convenient for those who are deaf, as during the dark of night they can feel the hour at a time when they cannot sec it. These sourdine or dumb parts have been left off of late years ; yet they are not without their advantages, as has been now shewn.
The late Julien Le Roy had tried to render repeating watches more simple, by suppressing the wheel-work which' serves to regulate the intervals between the blows of the hammers, and also the main repeating spring. This celebrated artist succeeded in these, to construct new re peating movements, of which several have been made. But it appears that the public have not found them very conve nient, so that this mode of composing them has not been imitated.
The only one of this kind which we have seen of Julien Le Roy's, was a very good one in the possession of John Rutherfurd, Esq. of Edgerston. Although they have not been copied, they certainly deserve to he so.
Repeaters have of late been made with springs in place of bells, which are a very ingenious substitute, it must be allowed, of Swiss invention, though they are as superfluous as bells. Considerable trouble is necessary in making and placing them. They ought never to be recommended, if it could be avoided ; but we are often obliged to yield to the fashion of the day, even when it does not coincide with our own opinion. When three or more hammers are used to give the quarters, we then would admit springs in place of bells, as when they are well tuned, they give a most beau tiful chime for the quarters : were bells introduced for this purpose, they would give a clumsy appearance to the watch. Julien Le Roy saw good reasons for setting aside the bell ; and no plan of a repeater will ever be superior or equal to that of his, which Graham frequently adopted in many of his watches, though his repeating motions were different ; Julien Le Roy's having what is called the plain, and Graham's the Stogden motion, a most ingenious con trivance, requiting great judgment to plan, and nice execu tion in making it. This motion is well adapted for half
quarters : Though we have hardly seen a French repeater with it, yet it is not unknown to the foreign artists, as ap pears from Thinut's work, torn. ii. p. 367, plate xxxvi. fig. 3. Paris, .1741. This repeating motion must have got its name from the inventor. Upon Myth ing after him when in London, in the year 1770, we learned, with much regret, that he had died a few months before in a charity work house, at a very great age. The name appears to be Ger man ; but whether he was a foreigner or an Englishman, we have not been able to learn.
We shall now lay before our readers a complete descrip tion of the repeating movement and motion-work of clocks and watches, which we have taken principally from Ber thoud's Essai sur I'Horlogerie Clocks that have a striking part, strike of themselves the hours, and some strike the hours and half hours ; but those having a repeating part strike only on a cord being pulled, if it is a clock ; and if it is a watch, when the pendant or pusher is !laced home ; thus two hammers strike the hour and the quarters, which the hands point to on the dial. We shall see, by the description of a repeating clock, how this is produced ; but before doing so, we shall give a general idea of this ingenious mechanism, which is nearly the same for a clock as for a watch.
In order to make a clock repeat the hour, (see Plate CCCV. Fig. 2.) the cord X is drawn, which is wound round the pully P, fixed on the arbor of the first wheel of a par ticular wheel work, the sole object of which is to regulate the intervals between each blow of the hammer. The ar bor of this wheel has on it a hook, which takes hold of the inner end of the repeating main-spring contained in the barrel B, Fig. 3. On this arbor is also a plain wheel G, Fig. 1. having fifteen pins in it which serve to raise the hammers, twelve of them for the hours, and three for the quarters. The number of blows that the hour hammer strikes, depends on the greater or less course which the pin wheel G is made to take when pulling the cord, and this course depends itself on the hour pointed at by the hands on the dial. Thus, if the cord is drawn when it is twelve hours and three quarters, the pin wheel is obliged to make an entire revolution ; at this instant the repeating spring brings it back, in which course it makes the ham mer give twelve blows for the hours, and then three for the quarters. To distinguish the quarters from the hours, a second hammer is added, which, with the first, makes a double blow at each quarter.