SUBSTITUTES FOR THE TRACTOR 227 



spreader. Stationary machines, as a rule, use rotary motion, 

 though, as in the threshing machine, some reciprocating parts 

 are often added. 



In Europe, and to a less extent in this country, great efforts 

 are being made to develop substitutes for the direct traction 

 method. Several schools of inventors have grown into 

 prominence, each with a different idea as to how best to 

 apply mechanical power to the soil. The majority advocate 

 direct traction. Another large and well-established school 

 would have the power stationary, or at least portable, the 

 working implements being drawn back and forth by cables. 

 A third group insists that motive and working power be com- 



Cable plowing scene 



bined in one self-propelling frame or unit, while a fourth ad- 

 vocates the use of animals for propelling the outfit and mechani- 

 cal power for driving the working parts. Nor can we overlook 

 entirely the efforts of men to replace the power of heat engines 

 by electricity from some cheap and abundant supply. 



CABLE PLOWING TACKLE 



As we have seen, the use of a cable and winding drum for 

 pulling plows is one of the earliest ideas in mechanical culti- 

 vation. A short cable, along which the motor propels itself 

 by winding the cable around a drum mounted on the frame, has 

 also been in quite common use for pulling engines out of diffi- 



