FARM EXPERIENCE WITH THE TRACTOR. 6 



the average farm, they have not been in actual use under service 

 conditions for a sufficient length of time to demonstrate their utility 

 conclusively. 



STEAM AND GAS TRACTORS. 



The self-propelled steam thrashing engine was the prototype of the 

 modern steam tractor, the latter differing from the former mainly in 

 the size of the drivewheels and transmission gears. In other words, 

 the steam tractor, generally speaking, was an outfit designed pri- 

 marily for stationary use, but it was gradually adapted to the 

 heavier work of hauling implements and to other work requiring 

 power. A number of years were required for its development, but it 

 finally proved its value on the large areas of prairie opened up for 

 settlement in the West. 



At its best, however, it had several serious disadvantages. It 

 burned bulky fuels, of which it could carry only a limited supply and 

 which required considerable time and labor in conveyance. It con- 

 sumed a large amount of water, which in a dry country was fre- 

 quently a serious handicap. It was heavy and cumbersome and 

 required a man of considerable ability to operate it properly. It 

 ordinarily employed a crew of three to five men and of two to four 

 horses. A delay of half an hour or more was often experienced in 

 getting up steam pressure sufficient to commence work, and consid- 

 erable fuel was consumed in keeping up steam during stops. In 

 many cases the fire would be maintained all night in order to have 

 the engine ready for work the next morning. 



These objectionable features were practically overcome by the gas 

 tractor. It burned a fuel of less bulk and attained a higher thermal 

 efficiency, so that it could easily carry sufficient fuel for a half day's 

 run, and in many cases for much longer. One 2-horse load of fuel 

 would keep the engine in operation for several days. It used com- 

 paratively little water, and, if desired, a low-priced oil could be sub- 

 stituted for water in the cooling system. It weighed less per unit 

 of power than the steam tractor, was shorter, and could therefore 

 turn in less space. While it demanded a thoroughly competent 

 operator in order to secure the best results, he could easily attend 

 to the entire operation of the engine and would frequently find time 

 to operate the plows as well, although the crew usually consisted of 

 two men and occasionally of three men and two horses. The motor 

 could be started in a moment's time, and no fuel need be consumed 

 when the outfit was idle. 



After the steam tractor had been used for plowing for several 

 years, an insistent demand developed for a plowing outfit without 

 the disadvantages of the steam tractor. The early gas tractors were 

 built largely to meet this demand. The gas tractor has therefore 



