RURAL ENGINEERING. 887 



not available, but after the sod was broken they proved an unprofitable in- 

 vestment for the individual fanner in a large percentage of cases. A few 

 owners have found the tractor a very profitable investment, doing its work more 

 satisfactorily and uuich cheaper than could be done with liorses, while a great 

 many discontinued its use after a trial. The percentage of owners reporting 

 favorably regarding the tractor decreases with the length of time they have 

 used their outfit, due partly to the fact that the older machines were not as 

 good as the later ones, but mainly to a better realization of the tractor's value 

 in their work. . . . Owners who report unfavorably regarding the tractor ob- 

 tain poorer average results than those who state that the tractor is a good 

 investment. . . . 



" The average life of a tractor as estimated by owners in North Dakota is 

 about six years, while the average life as estinnited by owners in States other 

 than North Dakota is about eight years. To judge by the small i)ercentage of 

 reports received for tractors three or more years old, it would appear that a 

 large number of outfits three, four, and five years old are no longer in use, 

 indicating that tlie average life is even less tlian six years. The plowing done 

 with tractors has been little, if any, deeper than that done with horses. Com- 

 bination work is not practiced to a great extent, and usually is limited to har- 

 rows or drags after the gang plow. The percentage of tractors which are op- 

 erated at night is comparatively small, varying from 11 to 14 per cent, al- 

 though the tractor's efficiency at night is very good. No injurious packing of 

 the soil is caused by the tractor's wheels if the soil is in proper condition to] 

 be worked. The item of repairs has been one of considerable importance i 

 connection with the use of farm tractors, but the data indicate that a large 

 percentage of such repairs have been caused by inefficient operation. 



" The necessity for the operator of a gas tractor being thoroughly trained 

 for his work, if a tractor is to prove a success, is obvious. . . . 



" The tractors which have been operated by kerosene show, as a whole, 

 slightly better average results than those operated by gasoline, indicating that the 

 heavier fuels can be burned at least as satisfactorily as the lighter ones. The 

 amount of kerosene used per unit of work, however, is usually slightly more 

 than for gasoline, which would appear to indicate that the combustion of the 

 kerosene is generally not as perfect as that of the gasoline. This is partly due 

 to tiie fact that many owners are burning kerosene in tractors equipped with 

 ordinary gasoline carburetors. . . . 



" The data apparently show that the tractors with drawbar ratings of 15 

 horsepower are giving slightly better results than either the larger or smaller 

 sizes. The tractor has not, as a rule, displaced its equivalent in work horses 

 as regards either power or value. Its purchase, therefore, usually increased the 

 investment in power, as well as in certain kinds of equipment. The necessity 

 for a large acreage, if the invested capital per acre is to be kept within a safe 

 limit, is very apparent, although in many farming communities a tractor may 

 prove profitable on a small acreage, provided the owner can obtain some lucra- 

 tive custom work for the tractor when it is not required on the home farm. , . . 

 The modern gas tractor of 10 or more horsepower has thus far. within its 

 limited area of use, proved to be an auxiliary of the farm horse rather than a 

 substitute. . . . 



"Up to the present time the tractor appears to have made for itself no 

 important place in the agricultural economy of this country. In a few limited 

 localities in the West where conditions especially favov its use large tractors 

 are used by some men with apparent profit. The general situation, however, 

 indicates that the large tractor is not to be a factor in increasing farming by 

 extensive methods and on a large scale, for a few years at least. Instead 



