THE PENDULUM. 



13 



oscillates to and fro that pendulum bob as it 

 is sometimes called. Observe, if I hold the 

 straight stick horizontally, as high as the posi- 

 tion of the balls at the two ends of its journey, 

 you see that the ball is in a higher position at 

 the two extremities than it is when in the 

 middle. Starting from one end of the stick, 

 the ball falls towards the centre, and then 

 rising again to the opposite end, it constantly 

 tries to fall to the lowest point, swinging and 

 vibrating most beautifully, and with wonderful 

 properties in other respects the time of its 

 vibration and so on but concerning which we 

 will not now trouble ourselves. 



Fig. 1. 



If a gold leaf, or piece of thread, or any 

 other substance, were hung where this ball is, 



