§ 95. SOILS. 165 



X. 



TO DETERMINE ALL EXCEPT MANGANESE, WITHOUT DIVIDING THE 

 SOLUTION. 



a. Eliminate P2O5 from tlic filtrate from tiie silica, by means of Sn 

 (VIII, b). 



b. First Filtr. (From the precip. by Sn.) Precipitate Al and Fe with 

 NH4HO and NH4C2H3O2, and treat this precipitate as directed for the 

 treatment of the correspondin<j one by NaCaHgOa in VIII, b. 



c. Second Filtr. Treat this, for the estimation of Ca, SO3, K, Na, and 

 Mg, as directed in Scheme V, 3, 4, 5 and 6. 



CHAPTER y. 



ANALYSIS OF SOILS AND ROCKS. 

 I. 



SOILS. 



95 • The following general method of analyzing soils, 

 by Emil Wolff, was approved at the annual meeting of 

 German Agricultural Chemists in Gottingen, in" 1864, 

 and is given in full in his work on agricultural analysis, 

 referred to in the preface. 



In his introductory remarks, Prof. WoliF writes : " Of 

 course it is not essential that the experienced chemist 

 should follow strictly all the methods for the separation 

 and quantitative estimation of particular components of 

 the soil, that are given here as guides for the beginner 

 in chemical analysis, and are used by me ; those methods 

 may be modified in many cases without impairing the 

 accuracy of the analytical work. But it is necessary 

 that all chemists who undertake accurate analyses of 

 soils should agree to follow the same course in regard to 



