CHAPTER I. 



Tab. I. — THE WATCH. 



Fig. 1. The hox, or barrel, containing the main spring, which is the 

 first power ; and the chain, which communicates the power to — 



Fig. 2. The fusee and great wheel. The fusee is tapered at the 

 top to correct the irregular recoil of the spring. The great wheel 

 turns — 



Fig. 3. The centre wheel and pinion, which makes one revolution 

 in an hour, carries the minute hand, and turns — 



Fig. 4. The third wheel and pinion, which turns the contrate wheel. 



Fig. 5. The contrate wheel, which makes one revolution in a min- 

 ute, and turns the balance or escape wheel. 



Fig. 6. The balance wheel, which acts upon the pallats of the 

 verge, and escapes or drops from one pallat to another alternately, 

 thereby keeping the balance in constant vibration. 



Fig. 7. The balance verge and balance or pendulum spring, which 

 regulates the whole machine. 



Fig. 8. The cannon pinion, affixed to the centre wheel arbour, on 

 which the minute hand is placed. 



Fig. 9. The minute wheel. 



Fig. 10. The hour wheel. The two last mentioned wheels are 

 turned by the cannon pinion and having a greater number of teeth, 

 move much slower than the cannon pinion, and mark the hour by the 

 hand on the dial. 



The above is a description of the several wheels alluded to by Pa- 

 Icy, Their relative situation, and combined movement, may be seea 

 by the simple inspection of a watch. 



