294 POWER AND THE PLOW 



power production. We must remember that coal and wood 

 are used only in steam engines, which waste far more energy 

 than the motors burning gasoline and kerosene. The animal 

 motor on the farm, converting into power for plowing a low 

 percentage of the energy it receives, places the products of 

 the field far down the list as power producers. 



The engine will outlast the horse, if properly cared for. 

 Repairs cost no more than shoeing and veterinary attendance. 

 The storage space for the animal and its food must be enor- 

 mously greater than that for the tractor. In the city, the 

 forty-horsepower auto seems lost in a corner of the barn which 

 formerly housed a half dozen horses, their feed and equipment, 

 and the modern garage in the back yard seems like a playhouse. 

 On the farm the shed for the tractor is insignificant compared 

 with the horse barn and needs far less care in its construction. 

 A ton of hay occupies from 400 to 600 cubic feet of space; a 

 ton of coal from 35 to 40 cubic feet; a ton of gasoline about 47 

 cubic feet; and a ton of kerosene about 40 cubic feet. Given 

 the space required to store the work horse's feed for an hour, 

 one would figure on about 10 per cent, as much per tractive 

 horsepower hour for a steam engine, 2.5 per cent, for the 

 gasoline engine, and 2.3 per cent, for the kerosene engine. 



One horse plows an acre per day. The steam plowing en- 

 gine plows thirty acres in the daytime, and as much more at 

 night, if required. The gas tractor, stopping less often for 

 supplies, may compare favorably with the larger steam tractor, 

 since it will travel more miles in a day for the same geared 

 speed. The horse must cease work for rest while either tractor 

 works on. The gas tractor carries fuel and water for the day. 

 It can go farther from the base of supplies than the horse, 

 which must have food and drink every eight miles of plowing, 

 or the steam tractor, which runs short of water in two. 



Endurance is the horse's weakest point, and flexibility his 

 strongest. By coupling from one to ten large horses together 

 in teams of different size, one has economical motors of from one 



