UNIVERSITY OF CALIFORNIA. 



DETERMINATION OF CHARACTEK OF SOILS. 



Observation in the Field Derivation, Position, Depth, 

 Substratum, Natural growth, Climate. 



Experience in cultivation. 



Taking of fair specimens difficulty precautions. 



Examination of subsoils best adapted to general pur- 

 poses. 



PHYSICAL PROPERTIES of soils quite as important as chemical 

 composition. 



"Lightness" "Heaviness" Porosity Absorption of 

 aqueous Vapor Water-holding power Capillary co- 

 efficient Color Specific" gravity. 



Difficulty and tediousness of direct determination of these. 

 Mechanical analysis as a substitute, sufficient for practical pur- 

 poses. 



Elutriation. Subsidence method faults. 



Hydraulic method. 



Apparatus of Noebel Fresenius Mueller Schoene. 



Mixed character of sediments, and inconstancy of re- 

 sults. Causes "Flocculation." 

 Preliminary preparation Boiling removal of gravel and clay 



prior to washing. 



The Churn Elutriator or Soil-washer Construction Precau- 

 tions in use. 



Character and nomenclature of sediments. 



Direct determination of Clay by precipitation. 



Action of common Salt. Lime. 



Influence in formation of bars at river mouths. 

 Importance of Flocculation Effects of tillage "Woolly" condi- 

 tion Tamping of clays. 



Molecular properties of sediments absorptive coeffi- 

 cients mechanical resistance. 



Estimation of tillability of soils; influence of sediments 

 on " lightness " and " heaviness ;" clay not the only 

 factor of "heaviness." 



Influence of Flocculation. 



Porosity ^s. Resistance to tillage. 

 Absorbing power of Soils. 



Not in direct ratio to clay. Examples. 



Influence of Sediments of Ferric Oxide of Humus. 

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