POWER AND THE FOOD SUPPLY 283 



tain maximum yields indefinitely, if production is to keep pace 

 with demand. 



The lack of power for plowing is the greatest obstacle to 

 the extension of our wheat raising area into virgin fields and 

 the realization of greater returns from our older lands. This 

 work of plowing with which man began his systematic labor 

 remains to-day his severest toil. For man, as well as animals 

 on the farm, the dusty monotonous work of plowing is the 

 hardest drudgery. Think of the power required to pull a 

 plow only the distance across the room, and then of the eight 

 and one fourth miles of furrow travel in every acre of land. 

 To plow a square mile with a twelve-inch plow, one man and 

 two or three horses must each walk 5280 miles, the team con- 

 stantly exerting power enough to move ten tons over a city 

 street. It is easier, and the distance less, to walk around the 

 earth at the equator than to follow such a plow turning a tract 

 of five square miles. To plow three townships the plowman 

 must walk as far as from the earth to the moon and back again, 

 and sixty thousand miles farther. To equal our annual tale 

 of plowing, seventeen to twenty plowmen must make a round 

 trip to the sun. Pulling a plow three and one half inches 

 deep through prairie sod is equivalent to lifting a constant 

 load of seven ' hundredweight. The plowmen in the United 

 States turn over eac^h year two billion tons of earth. They 

 exert power enough to lift the visible portion of Manhattan to 

 one and a half times the height of the Eiffel Tower, and the 

 cost of their work places an annual tax of $25 on every family 

 in this broad land of ours. 



Plowing is the greatest single item of power consumption 

 on the farm. To plow an acre of old land, the farm horse 

 works from eight to fifteen hours under a greater strain than 

 in any other task. One fifth his total hours of work and one 

 third his yearly expenditure of power in the Corn Belt are at 

 the plow. In small grain sections one fourth his hours and 

 one half his power are expended in turning^the soil. Plowing 



