THE LEVER 253 



obliged to contract with a force of over two hundred 

 pounds. 



The lever is the fundamental basis for many machines, and 

 the moving pulley and the gear are only special forms of 

 levers. The human and other skeletons contain many 

 examples of the lever. 



References : 



1. 1803:151-154. The Lever. 



a. 1509 : 53-55. Kinds of Levers. 



6. 1801 : 83-85. The Lever, its Advantage and Use. 



c. 1802 : 146. The Lever. 



d. 1804 : 102-104. Experiments with the Lever. 



e. 1805 : 84-88. The Lever and its Law. 



/. 1806 : 65-68. The Lever, Straight and Circular. 



g. 1807 : 123-127. The Lever and its Applications. 



h. 1808 : 88-93. The Lever Straight, Bent, Compound. 



i. 1809 : 81-83. The Lever and its Applications. 



j. 1810 : 2-7. Levers. 



k. 1811 : 355-356. The Lever. 



Experiment 82. The Lever. 



Apparatus : A stick 36" X 1" X J", with holes bored every 

 inch through the middle of the flat side, ring stand, nails to 

 fit holes, 3 double hooks of wire to hook over both ends of a 

 nail when it is pushed through a hole in the stick, having a 

 third hook opposite the double part, 12 iron balls all of the 

 same size, with hooks on opposite sides. 



a. Push a nail through the middle hole, and support the 

 stick, by one hook, on a ring stand. Push a nail through the 

 first hole to the left and another nail through the second hole 

 to the right. How many more balls can be hung on one side 

 than on the other ? On which side is the greater weight ? 

 Double the number of balls on one side. How many times 

 the original number can now be supported on the other side ? 



