PRIMITIVE CLOCKS. 



189 



itself turns a small pinion that carries the "fly-fan." The use of the 

 fan is to keep an even motion. The large wheel that we have spoken 

 of turns once at every stroke of the bell. In Fig. 5, a wire, e, runs 

 over to the center wheel, D. In Fig. 3, a pin on the center wheel 

 pushes up this wire when the clock is ready to strike. If the end of 

 the wire (in Fig. 5) rests at the four notches, it shows that four o'clock 



Fig. 5. 



has been struck. If the center wheel pushes the wire up again, or pulls 

 it out from the notch where it is resting, the large wheels at B are 

 released ; the weight commences to turn A and B, and the pins in A 

 set the hammer c to striking the bell d. It keeps on striking until 

 five has been struck. The wire then drops into a notch and holds 

 the striking-wheel fast until the center wheel moves the wire again 

 thus saying that it is time to strike six. The wheels then turn again 

 until the wire comes down and stops them. Alarm-clocks have an 

 arrangement by which the spring that sounds the alarm is let loose at 

 the hour when the owner wishes to be awakened. 



The boys who went to school in New England sixty years ago had 

 no such device to waken them in cold winter mornings as the modern 

 alarm-clock ; they had to waken each other, in order to have a good 

 start in kindling their fires, so that they could enjoy an hour's hard 

 study, and sometimes a recitation, before breakfast. 



