THE TRACTOR PLOW HITCH 



169 



stantly moves from side to side and up and down on 

 account of the variations in shapes and the intensity 

 of the pressure of the earth against the bottom. But 

 for the sake of explaining the principle we will assume 

 that this point is correct. In actual practice a slight 

 variation does not materially affect the working of the 

 plow. 



Being obliged to turn the tractor in this direction shows that the draft 

 of the plow has a tendency to pull the wheels toward the plowed ground. 

 This puts enormous end-thrust on the front of the tractor, and demands 

 additional power for operation. 



It is impossible to pull a plow in the true line of draft 

 because the hitch would be below the surface of the 

 ground. 



The fact that the power cannot be operated in a line 

 parallel with the landside through the center of draft of 

 the plow necessitates two lines of draft. These two 



