464 TRANSFERRING AND TRANSFORMING ENERGY 



The lever was probably one of the first machines used 

 by primitive man. He pried up rocks and pried open 

 logs to get the roots and small animals he needed. It 

 was to him simply a convenient way of using a stick. But 



when Archimedes, 



the greatest mathe- 

 matician of ancient 

 times, worked out 

 the principle of this 

 simple machine, he 

 was so much im- 

 pressed with the 

 mechanical advan- 

 tage to be derived 

 from its use that he 

 said, " Give me a 

 fulcrum on which to 

 rest and I will move 

 the earth." 



He found, as was 

 indicated in Experi- 

 ment 145, that the 

 longer the power arm 

 is than the weight 

 arm, the greater is 

 the weight a given 

 force can lift, but 

 the smaller the dis- 

 tance it can lift it. If the experiment could have been accu- 

 rately conducted, it would also have proved that the power 

 multiplied by the distance the power moves is equal to the 

 weight multiplied by the distance the weight moves. 



GRINDING CORN, SCOTCH HIGHLANDS 

 A simple application of the lever. 



