The same appearance is sometimes seen at jewelled pivot holes, and has been erroneously supposed to be produced by the operation of the pivot on the hole. It is singular that oil will act more forcibly on fine brass th ,n on the common sort, or even on copper ; a metallic soap some what resembling verdigrease will soon show itself on the former, while the latter will have no appearance of being injured. But we are not to infer from this, that copper boles would be preferable to those oracle in line brass ; for although the oil in this case would be more durable, front its acting more slowly on copper than on brass, yet the increase of friction from the copper would more than counterbalance this advantage. It can hardly have escap ed the eye even of the most indifferent observer, that oil acts more readily and forcibly on new than on old work. On the former, it will frequently show itself in the course of 24 hours. Oil varies so much in its quality, that some will become so thick and viscid in the course of a few months, as to stop the machine altogether. This has oc curred in the e.,perience of a very celebrated artist, who inlorms us that " his regulator, which has been found to gu to a greater degree of accuracy (though not to a second in two months, as has been said of others) than even that at Verona, as observed by the astronomer Cagnoli, or that at IVIanheirn, as observed by Mayer, was found to perform very indifferently alter being cleaned, and at the end of three or four months stopped altogether, which arose from the application of bad oil." We are of opinion, that where the pivots are small, and the revo lutions of the wheels quick, jewelled pivot holes are the best. It. will not be an easy matter to do without oil, particularly in pocket or box chronometers, although as tronomical clocks or regulators may be so constructed as not to require it.
On the Machinery for going in time of Winding.
THE earliest machinery for going in time of winding is the simplest and best that has yet been produced ; al though, upon the whole, it may not be so convenient in its application. In the old thirty hour clocks, the first wheel or the going part had on its arbor a fixed jagged pulley A : (See Plate CCCIV. Fig. 6.) On the arbor of the first wheel of the striking part was a moveable jagged pulley H, with click and ratchet to it. Over these, and through or under the pullies of the countrr weight jz and main weight P, went an endless cord, woven either of silk or cotton. Both parts of the clock were carried On by a single or main weight ; and, when winding it up, this was done by the striking pulley ; by which means, the weight acted constantly on the going part. This is a method which we adopted in some common regulators, and afterwards found it was the same that Berthoud had used in some of his. The moveable and winding up pulley with its ratchet was on a fixed stud, having a click and spring, which were fixed to one of the plates, as was also the stud. The other pulley was on the arbor of the first wheel, and fi red to it. The only inconvenience
and objection to this contrivance, particularly in eight day clocks, arises from the wearing of the cord on the jagged part of the pullies. which produces a great deal of dust, and makes the clock get sooner dirty than it would do, if this was effected in a different way. In clocks which go a month, or six months, as some of Berthoud's did, this will be very much obviated, particularly with a fine and well wove silken cord.
There is a very ancient way of going while winding, which was long applied to the fusees in clocks and watches. On the inside of the great wheel is another wheel, whose teeth are cut to look inward to the centre, upon which acts a pinion of six, which runs in the bottom of the fusee, and is turned round with it. The fusee arbor is free within both the great wheel and the fusee ; upon it is fixed the fusee ratchet, and a wheel with about half the number of teeth of those in the inward toothed wheel. It is evident, that if the fusee arbor is turned round, the wheel fixed on it, which acts also into the pinion of six, will by this make the pinion turn ; and this again, acting on the inside wheel teeth, will apply as much force to it as the fusee requires in setting up. When wound up, the click in the great wheel, as in the ordinary way, stops the fusee by the ratchet from running back. This method takes six times longer of winding up than by the common way ; and the great strain which is laid on the pinion and inside wheel teeth soon destroys them. With a little more apparatus, a fusee of this kind can be made to wind up whichever way the arbor is turned ; hence it got the name of the drunken fnaee (See the particulars of it in Thiout,vol. ii. p. 383. and Plate xxxviii. Fig. 14.) A .going in time of winding, of later application to clocks and regulators, consisted of an ardor within the frame, on which was a pin, and an arm inside, with a nib and deer's foot joint ; another arm on the outside when pulled down, served to make the jointed nib rise and pass the third wheel teeth ; a spring acting on the pin brought the nib in a contrary direction, to act on the third wheel teeth, by which it gave motion to the swing wheel during the time of winding, and continued to do so until getting clear of the teeth.
The general method which is now adopted, both in clocks and chronometers, consists of an auxiliary spring, ratchet, and detent. In clocks, two springs are somewhat used ; being doubled round, are screwed by one end to the back of the auxiliary ratchet ; the other end is made to act against the arms or crosses of the great wheel. On the op posite side is the click, which acts with the barrel ratchet ; and when the force of the weight is taken off by winding up, the force of the springs act on the great wheel, and not being allowed to bring the auxiliary ratchet forward, which they would do; but this is prevented by the detent, consist ing of an arbor whose pivots run in the frame, and an arm acting against the face of the small teeth in the auxiliary ratchet.