THE WORKS OF A WATCH. 377 



spring ; it is here represented relaxed, as when 

 the watch is run down. 



On the left hand of this figure we have the 

 barrel^ a cylindrical box, in which the spring is 

 coiled ; and the extremity of the spring in the 

 centre of the coil being fixed to an axle in the 

 centre of the barrel, while the outer extremity is 

 attached to the inner circumference of the barrel 

 by a steel pin, the barrel must thus turn round as 

 the spring uncoils. 



The pyramidal body on the right is the fusee. 

 In winding up the watch, the key is fixed on the 

 pivot of this body, turns the fusee, and through 

 the chain which joins it to the barrel, the barrel is 

 also turned round, and the spring within wound 

 close up to its axle. When the key is removed, 

 the spring acts, the barrel slov/ly revolves, and 

 the chain, wound upon the barrel and drawing on 

 the fusee, turns the fusee round. On the base of 

 this body we observe the spur teeth of a wheel. 

 This wheel is the source of all the movements in 

 the watch. 



We must not neglect to observe a pretty con- 

 trivance to make the mechanical power of the 

 33* 



