THE ANALYSIS OF VIRGIN SOILS. 



341 



valley of the Mississippi river, and known locally as the 

 " Table lands ; " a noted cotton-producing upland region. The 

 brown or yellow, moderately clayey loam is of great uni- 

 formity throughout its region of occurrence, and is evidently 

 derived from such widely-spread sources that it represents no 

 special rock or complex of rocks. Its natural growth is a mix- 

 ture of oaks and hickories, strong and well-developed trees, 

 such as any land-seeker would at once approve for settlement. 

 Its cotton product when fresh was a 4OO-pound bale of cotton 

 lint per acre. It may therefore well be considered a typical 

 generalized soil of the humid upland of the Mississippi valley. 

 Its physical analysis is given in chapter 6, it being No. 219 

 of the table on p. 98. 



Strength of Acid used. Three different strengths of acid 

 were simultaneously employed, viz., chlorhydric of i.io, 

 1.115 and 1. 1 60 density. With these the soil was digested at 

 steam heat in porcelain beakers covered with watch glasses for 

 five days each, then evaporated and analyzed as usual. The 

 results were as follows : 



ANALYSIS WITH ACID OF DIFFERENT STRENGTHS. 



It will be noted that the strongest acid produced the smallest 

 amount of decomposition of the soil silicates, e. g. the silica 

 soluble in carbonate of soda solution being 3% less than in the 

 case of the acid of medium strength ; a result possibly due to 



