2 BULLETIN 174, U. S. DEEABTMEXT OE AGPJCULTUBE. 



exceptional, results from their outfits. At the same time, men who 

 hare not succeeded are not usually inclined or afforded an opportunity 

 to make their experiences generally known. It is necessary to con- 

 sider carefully the. results obtained by all users, whether they have 

 succeeded or failed, in order to obtain correct information as to the 

 present status of the farm tractor. The data in this bulletin are based 

 upon the experience of a large number of users in both classes. It is 

 important for everyone interested that a reliable and impartial survey 

 be made available. The relative efficiency of various makes of 

 tractors is not considered in this bulletin. It is obvious, however, 

 that this factor of the efficiency of some particular machine may be a 

 most important one to the individual farmer. 



DESIGNATION OF TRACTORS. 



Owing to the numerous terms used to designate tractors in various 

 sections, it may be well to state that in this bulletin the term "gas 

 tractor" is used to designate those machines which derive their power 

 from an internal-combustion engine burning a vaporized fuel (regard- 

 less of the kind of oil burned), which are designed for pulling imple- 

 ments and for doing stationary work. When the term "gasoline 

 tractor" occurs it denotes an outfit of the kind just mentioned in 

 which gasoline is regularly used for fuel. Similarly, the term " kero- 

 sene tractor" is used to denote a "gas tractor" in which kerosene is 

 the ordinary fuel. By a "steam tractor" is meant an outfit deriving 

 its power from steam generated in a boiler, heated by means of a fire 

 of coal, wood, straw, or similar fuel. 



The smaller machines, designed especially for cultivation, plowing, 

 etc., commonly known as "autoplows" and "autocultivators," in 

 which the tillage implement and power plant are combined in one 

 unit, have not been considered in this bulletin, as these do not prop- 

 erly come under the title of tractors. While there are numerous types 

 of these small self-propelled plows and cultivators intended particu- 

 larly for use on small farms, few of them have been in actual service 

 long enough and in sufficient numbers to demonstrate their ability 

 to perform the work for which they are intended. 



Xor should the data or remarks contained herein be considered as 

 applying to the various types of small tractors designed to pull two 

 or three plow bottoms and selling at a comparatively low figure, large 

 numbers of which have been placed on the market during the past 

 few months. These small, low-priced outfits represent the latest 

 phase of the development of the farm tractor and may fairly be con- 

 sidered as belonging to a different class than those under discussion 

 in this bulletin. While they give promise of proving an economical 

 source of power for a great deal of the field and stationary work on 



