SUBSTITUTES FOR THE TRACTOR 231 



good seed bed without further travel over the ground. In 

 this way, as with a traction engine pulling plows, disks, and 

 harrows at one time, the traction wheels are always on solid 

 footing, and there is less waste of power in propulsion. Several 

 machines of this general character are now claiming attention, 

 abroad. One great objection to this principle, especially in 

 the New World, is that the burying of vegetation is often the 

 prime object of plowing. The cylinder would undoubtedly 

 mix this trash with the soil more thoroughly than the plow, 

 yet the lighter material may usually be found on the surface 

 in considerable quantities. 



A South Dakota college professor has attached to the rear 

 of a wide-wheeled tractor a spiral tillage device which is actuated 

 by a chain and sprocket. A Kansas farmer repeats an idea 

 recently brought out in France i. e. y a series of small 

 plows connected by radial rods to a rotating shaft, each one 

 imitating the action of a spade upon the soil. In another 

 outfit, made in Italy, the ordinary plowshare is replaced by 

 a pair of auger-like screws which precede the machine and are 

 rotated in directions opposite to each other as the machine 

 moves forward. 



The use of electricity in plowing has been limited. The 

 self-contained electric motor has never been perfected, at 

 least in an economical way. To generate, by means of primary 

 cells, the amount of power required even for very light work is 

 out of the question, owing to the cost, bulk, and general unsuita- 

 bility of the necessary batteries. The storage battery, which 

 has been successfully used on small automobiles and trucks, 

 is too bulky, costly, and expensive in operation to be practicable 

 on a heavy plowing machine. 



One development in this line is the self-contained "gasoline- 

 electric*' motor. In this the power of a gas engine is trans- 

 formed by a generator into electricity, and this used to drive 

 the machine. In some present motor trucks all four wheels 

 are driven, with a small motor on each wheel. A storage 



