74 



MECHANICS. 



Fig. 55. 



ward, and loosens the stump ; while in this position, 

 another chain is made to connect gtoh, and the horse 

 is turned ahout, and draws the lever backward to i, 

 which still further increases the loosening ; a few rep- 

 etitions of this alternating process tears out the stump. 

 Very strong chains are requisite for this purpose. 

 Large stumps may require an additional horse or a 

 yoke of oxen. Where the stumps are remote from 

 each other, iron rods with hooks may he used to con- 

 nect the chains. 



The power which may be given to this and to all 

 other modes of using the lever, as we have already 

 seen, depends on the difference between the lengths of 

 its two arms. A yoke of oxen, drawing with a force 

 of 500 pounds on the long arm of a lever 25 feet long, 

 will exert a force on the short arm of six inches equal 



