54 



MECHAXICS. 



corner of the platform, and rest on one point at the centre. 

 We have taken the two only, to simplify the explanation. 

 A powerful stump-extracting machine, allowing a suc- 

 cession of efforts in the use of the lever, is exhibited by- 

 fig. 55. The lever, a, should be a strong stick of timber, 

 furnished with three massive iron hooks, secured by bolts 

 Fig. 55. passing through, as 



represented in the 

 figure. Small or 

 truck wheels are 

 placed at each end 

 of the lever, merely 

 for the purpose of 

 moving it easily over 

 the ground. The 

 stump, 5, used as a 

 fulcrum, has the 

 chain passing round 

 near its base, while 

 another chain passes 

 over the top of the 

 stump, c, to be torn 

 out. A horse is at- 

 tached to the lever 

 Lever Stiimj) MAchine. at d^ and, moving tO 



, draws the other end of the lever backward, and loosens 

 the stump ; while in this position, another chain is made 

 to connect g to A, and the horse is turned about, and draws 

 the lever backward to ?*, which still further increases the 

 loosening ; a few repetitions of this alternating process 

 tear 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 be used to 

 connect the chains. 



The power which may be given to this and to all other 



