98 MECHANICS. 



annexed figures, the one should be chosen which is 

 lightest near the blade, nearly all the motion being in 

 that direction, because the upper end is the centre of 

 motion. The right hand, at a, acting partly as the 

 fulcrum, the hoe handle should be slightly enlarged at 

 that place. Fig. 81 represents a well-formed handle, 



Fig. 81. 



r^T — ' — 



CI 



Well-formeA Iwe . 



Fig". 82 a clumsy one. Rake handles should be made 



O" 



Fig. 



P 



Badly-formed hoe handle. 



largest at the middle, or where the right hand presses. 

 Rake-heads should be much larger at the centre, and 

 tapering to the ends, where the stress is least, the two 

 parts operating as two distinct levers, acting from the 

 middle. Horse-rakes might be made considerably 

 lighter than they usually are by observing the same 

 principles. The greatest strength required for ploW' 

 beams is at the junction with the mould-board, and 

 the least near the forward end, or furthest from the ful- 

 crum or centre of motion. 



Now it may be that the farmer who has had much 

 experience may be able to judge of all these things 

 without a knowledge of the science. But this scien- 

 tific knowledge would serve to strengthen his experi- 

 ence, and enable him to judge more accurately and 

 understandingly by showing him the reasons ; and in 

 many cases, where neiv implements were introduced, 

 he might be enabled to form a good judgment before 



