MOTIVE POWER 



483 



work that had been rendered slow and inefficient by the 

 number of horses required to supply the necessary power. 

 The expense and labor of operating a steam engine prevented 

 its adoption as a farm power except on large farms having 

 sufficient work to require an engine throughout a season 

 for threshing, sawing, or other heavy work. The number 

 of horses needed on a large grain farm to furnish the 

 traction power for seeding, harvesting, and threshing was 

 not sufficient to do the plowing in the limited season in 

 which it had to be done. To avoid maintaining a number 

 of horses for the plowing season only, the farm operators 

 experimented with their steam tractors which, with a skilled 

 crew, were available in the 

 plowing season. The re- 

 sult was that the plowing 

 could be done by the 

 horses required for the 

 other operations of grain 

 farming supplemented by 

 the steam tractor, and the 

 practicability of plowing 

 large unobstructed fields 

 with steam threshing en- 

 gines was clearly proved. 



Gas tractor. The development of the gas engine and its 

 application to the small tractor (Fig. 373) operated by one 

 man have placed a machine suitable for both tractor and 

 stationary work within the possibilities of the ordinary 

 farm. The desirability of adding a tractor to the farm 

 equipment is open to much discussion. It is dependent on 

 the mechanical ability of the landowner, the nature of the 

 soil, the work that can be performed by the tractor, and 

 the number of horses which are required to carry on the 

 farm work in addition to the tractor. Men with mechanical 

 ability prefer working with a machine rather than with 

 a horse, and they substitute mechanical methods wherever 



After J. I. Case Threshing Machine Co. 



F!G. 373- A wheel gas tractor 



