382 



University of California Publications in Agricultural Sciences [Vol.3 



investigators have emphasized. But if there were such a scheme, 

 similar to that which the Bureau of Soils uses, 26 it would be an easy 

 matter to compare the results obtained through the use of the elutri- 

 ator. and determine whether or not the soils examined belong to a 

 given class. The simple comparison of the quantities, in different 



40% 



0.2.5- 0.5 1.0 2.0 4.0 8.0 16. 32. 64-. Grits. 

 Size of Particles. mm. 



Fig. 4. Graph showing the results of the Hilgard elutriator method of 

 mechanical analysis on the nine samples of Hanford fine sandy loam. 



samples, of any given separate or separates is not absolute. For it 

 must be realized that the conception of a soil class includes a certain 

 range in the quantities of particles of the various sizes. This must 

 be so since soils are ordinarily grouped into but ten or twelve class 

 textures, while there exist among soils those with all gradations in 

 the quantities of particles of the various sizes. 



26 Instructions to Field Parties, U. S. Bur. Soils, Bull. 1914, p. 75; ibid., 

 Bull. 85 (1912), p. 28. 



