224 Mr AIRY ON A NEW CONSTRUCTION OF THE GOING-FUSEE. 



adjustment is corrected by a small motion of the lever-frame. I should 

 think that an inclination of 40 3 to the horizon would be found convenient. 



For fully understanding the action of the mechanism, the following 

 remarks may be useful. 



If the wheel k, fig. 3, be forced a little in the direction opposite to that 

 of winding up, the clock will go for some time without any descent of W. 

 For, (using a to denote the point of the barrel where the teeth of k act on 

 those of h), abc may then be considered as a lever whose fulcrum is c: the 

 force acting downwards on a, will depress b, and will make several teeth of 

 the internal ratchet glide under f, and will, at the same time, carry d further 

 in the horizontal direction ; then if the force on k ceases, the force w, acting 

 now with increased statical momentum, will thrust f against the teeth of 

 the ratchet, and will maintain the pressure and motion at c, by the motion 

 of the whole lever-frame and toothed wheel round a. In this respect, the 

 action of this mechanism is similar to that of Harrison's going-fusee. 



If the distance ba (using a to denote the fulcrum of the lever-frame) be 

 greater than the radius of the barrel, the force which acts on c during the 

 winding up, is greater than that which acts during the ordinary going of 

 the clock. If b a be less than the radius of the barrel, the force which acts 

 during the winding up is less. 



It has been supposed in the whole of this explanation, that b and c are in 

 the same horizontal line, and that the pressure which the teeth of the wheel 

 exert on these of the pinion is to be upwards. If the pressure is to be 

 downwards, the only difference in the form of the construction will be, that 

 the lever-pivot a will be between the wheel-center and the pinion-center, 

 and that the inclined arm ad of the lever-frame will be turned towards the 

 pinion ; its length, &c. will be determined by the same considerations as in 

 the case which has been fully treated. If b and c are not in the same 

 horizontal line, all that is necessary is, to make the barrel-line pass over a 

 pulley, so that the direction of its action shall be perpendicular to the line 

 be : no alteration whatever is needed for the arm ad, or the line which acts 

 on it. An instance of such a case is represented in figure 6. 



