SOME PHYSICAL PROPERTIES OF THE SOIL 125 



ds 1 agreed rather closely (see Fig. 20). The effective 

 diiimeter of the particles of some of our common soils, to- 

 gether with the effective surface exposed, is given 

 below : 2 



The method of King has certain advantages, besides 

 giving an idea as to the number of particles, their internal 

 surface, and the relation of this internal surface to soil 

 conditions. In the first place, a single figure is used 

 to express the size of particle ; secondly, from this effec- 

 tive size of particle the probable rate of air and water 

 movement may be calculated ; and, thirdly, the number 

 of particles and the internal surface calculated therefrom 

 have a fairly definite relationship to the plant, as such 

 figures are so closely correlated to the circulation of air 

 and water. 



1 King, F. H. Physics of Agriculture, p. 123. 

 by the author, Madison, Wisconsin. 1910. 

 2 Ibid., p. 124. 



Published 



