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PHYSICAL GEOGRAPHY. 



THE EXACT COMPOSITION OF OUR SOILS. 



In addition to our general description of the soils of the state, it 

 may be desirable to present analyses of them from different localities. 

 Dr. Jackson, in his final report, gave the results of a large number, 

 which I will reproduce in the form of a table. In analyses made at the 

 present day, greater attention is paid to the determination of phosphoric 

 acid, the alkalies, and nitrogenous compounds, than appears to have been 

 devoted to the subject by Dr. Jackson. The table will show the average 

 composition of the soils of the state, in respect to insoluble silicates, the 

 peroxide of iron, alumina, lime and its compounds, magnesia, and the 

 organic matter. The column stating the percentage of water is not of 

 any practical importance. In a few cases special determinations were 

 made of the organic matter, the following being invariably present: "(i) 

 Crenic acid and crenates of bases; (2) apocrenic acid, combined also 

 with bases ; (3) humic acid, combined also with bases ; (4) humic, or neu- 

 tral undecomposed vegetable matter; (5) extract of humus, and (6) a 

 second extract, not yet named, separated from the above ; (7) phosphoric 

 acid in minute quantities." 



ANALYSES OF SOILS BY DR. JACKSON. 



