238 E. A. Schneider — Analysis of a Soil 



or 



I. 2-8500g rm clay 14*46 per cent 



II. 3-4232 sediment<-25 mm h. v._ ___ 17*38 " 



III. 10-0811 " -25 mm h. v.-8 mm h. v. 51*17 " 



IV. 3-3241 " 8 mm h. v.-64 mm h. v. 16*86 " 



19-6784 99-87 " 



These four fractions, obtained by mechanical analysis, repre- 

 sent the natural and characteristic subdivisions of this soil, as 

 the general aspect, the microscopic examination and the chem- 

 ical analysis have shown. They are described as follows : 



I. Clay / has a brownish yellow' color, and appears amorph- 

 ous under the microscope. 



II. Silt, or sediments <*25 mm h. v ; has a bright brick-red 

 color. Under the microscope most of the soil-constituents 

 which can be detected in the fractions composed of sediments 

 of higher hydraulic values are visible also in this fraction with 

 the exception of magnetic iron. All the iron in this fraction 

 appears to be in the form of peroxide. 



III. Sediments -25 mm h. v. — 8 mm h. v. ; have a light choco- 

 late color ; the " streak ' ; of the finely triturated powder is 

 gray and approaches that of the mother-rock, being only 

 slightly darker with a tinge of brown. The subdivisions of 

 this fraction appear under the microscope very much alike ; 

 particles of magnetic iron are discernible in all of them and 

 are larger with the increase of the hydraulic values. 



IV. Sediments 8 mm h. v. — 6Jb mm h. v. ; appear grayish black, 

 somewhat like the mother-rock, when coarsely pulverized. All 

 constituents of the mother-rock can be discerned under the 

 microscope in this fraction in an unchanged state. 



Since it thus appears that the natural subdivisions of this 

 soil correspond with those obtained by mechanical analysis I 

 undertook the chemical analysis of these four fractions. 



Plan of chemical analysis. — My plan was to execute a 

 complete analysis by fusion of each of the four fractions, in 

 order to ascertain their ultimate composition ; further, to an- 

 alyze the same fractions by extraction with hydrochloric acid 

 both in their natural state and after previous trituration, in 

 order to be able to compare them more directly, for estimating 

 their agricultural value. The analysis of the soil itself, tritu- 

 rated and untriturated, by fusion and extraction, entered also 

 into my plan of work. Lack of time, however, prevented me 

 from executing all of these analyses ; but the data which I 

 have obtained enabled me to draw some conclusions. 



Analytical methods. — The analytical methods which I have 

 used in this comparative investigation are somewhat different 



