44 THE PRINCIPLES OF AGRICULTURE 



will then require 1,000,000,000 of them to completely fill the 

 cubic inch, while their aggregate surface area must measure 

 3141.59 square inches." 



53b. Another illustration may be taken ("Texture of Soil 

 and Conservation of Moisture," being a first lesson in the Cornell 

 farmer's reading course): "Let us suppose the soil in one of 

 your plowed fields is in little lumps of the uniform size of inch 

 cubes — that is, one square inch on each side of the cube. How 

 many square inches of surface has that cube exposed to root 

 contact and moisture film ? Now imagine that one of these inch 

 cubes is broken up into smaller cubes measuring one -eighth of 

 an inch, — how many square inches of surface will you now have 

 exposed to root contact and film moisture ? Now reflect what 

 you have done in breaking up the inch cube of earth. The 

 amount of earth has not been increased one atom ; yet, by fining 

 it, you have increased just eight times the root pasturage and 

 surface for water film. The practical point of this lesson is that 

 by superior tillage you can expand one acre into eight, or by 

 neglectful management eight acres can be reduced to one. It 

 also demonstrates why a skillful farmer can produce as much 

 from fifty acres as a careless one can from four hundred, and 

 also confirms the assertion that success in modern agriculture 

 depends more on the size of the farmer than upon the size of 

 the farm." 



53c. This hning or dividing of the soil, therefore, increases 

 the feeding area for roots ; or, as Jethro Tull said, it extends 

 the "root pastiirage." "The value of simple tillage or fining of 

 the land as a means of increasing its productivity was first clearly 

 set forth in 1733 by Jethro Tull, in his 'New Horse Hoeing Hus- 

 bandry.' The premises upon which Tull founded his system are 

 erroneous. He supposed that plant roots actually take in or ab- 

 sorb the fine particles of the earth, and, therefore, the finer and 

 more numerous these particles the more luxuriantly the plant 

 will grow. His system of tillage, however, was correct, and his 

 experiments and writings have had a most profound influence. 

 If only one book of all the thousands which have been written on 

 agriculture and rural affairs were to bo preserved to future gen- 



