XXXI 



THE CHOICE OF POWER 



IN SELECTING a tractor for plowing, there are 

 countless factors to be taken into consideration. 

 In choosing a particular motor out of a general class, 

 its adaptability to the most pressing work must 

 be considered. However, before coming to that point, the 

 broader question of the type of power must be settled. It 

 would be next to impossible here to compare intelligently the 

 multitude of breeds and types, but a brief comparison of the 

 animal, steam and gas motors should be reviewed before making 

 the final selection. In purchasing a motor for plowing, one 

 should satisfy himself as to the investment; the efficiency ia 

 various particulars; the question of fuel supply; the cost of 

 maintenance during work and idleness; the attendance re- 

 quired; the concentration of power; the speed; effect upon the 

 soil; the range of usefulness; the endurance and the many 

 phases of each and every one of these essential considerations. 

 The horse is the product of thousands of years of natural 

 selection and of three centuries of careful breeding. The best 

 examples of his kind have seen but little improvement during 

 the century and a half of steam engine history. The steam 

 tractor is old and the gas tractor new. The traction mechan- 

 ism of both is in about the same state of perfection, but in a 

 quarter of a century of real development the gas engine has 

 become thermally much more efficient than the steam engine. 

 We may look for more rapid progress in the gas engine than in 

 the steam engine or the horse, but as an average of all represen- 



