DRY-FARMING 



the direct traction method, that is to say, 

 where the engine travels over the land 

 and drags the plows, harrows, packers, 

 and seeders along with it. This may be 

 avoided by what is termed the double en- 

 gine system, where the engines remain 

 stationary, and the tillage implements 

 are drawn across the field on a steel 

 cable. The advantage of the double en- 

 gine system over the direct system may 

 be summed up as follows : 



(1 ) The engines do not travel over the 

 fields, but move along the headlands, and 

 so the cropping ground is not damaged 

 by the heavy weight of the engines. 



(2) The whole effort of the engine 

 goes directly into the work of the plow, 

 whereas it has been estimated that quite 

 three fifths of the power given off by 

 the direct traction-engine is required to 

 propel itself. 



(3) With the double engine system the 



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