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THE ROYAL SOCIETY OF CANADA 



to the bench and a block of wood, F, with an inset piece of brass 

 bearing a sharp vertical line, I, follows up the ball. The position of 

 the index is read to 1/10 of 1/lOth of an inch. 



In Fig. 1, E shows the ball hanging in its position of rest with the 

 block F in contact with it and E\ FS show their positions when the 

 chain has been used to pull the ball back. Fig. 2 (plate) gives a 

 photograph showing the ball in the displaced position. 



The experiment from now onward is described in abbreviated 

 "Instruction Sheet" form with the addition of a few numerical results. 



Experiment I. — Find the relation between the force required to 

 produce a horizontal displacement and the magnitude of that displace- 

 ment. 



Start from the position of zero displacement and loop one ring 

 after another over the post. Read the dynamometer. The dynamo- 

 meter reads to ounces. Double that reading gives very nearly the 

 force in poundals. Therefore, record forces in poundals. Follow up 

 the ball with the block F, and take the scale reading. Enter up 

 results as indicated. 



