The Soil. 
19 
agree, and suggest a common origin for wide areas of our surface 
soils. 
The alkalies are lower than one would expect, judging from 
the number of feldspar particles which are present, and the ratio of 
the soda to the potash is high, as the feldspar recognizable is very 
predominantly orthoclase. The silicic acid is lower than the ap¬ 
parently large number of quartz grains present would suggest. The 
orthoclase contains, in round numbers, 66 per cent, of silicic acid, 
while the average percentage of this acid in these soils is 68.6 per 
cent., which seems lower than the macroscopic examination suggests. 
PORTIONS OF FINE EARTH EXAMINED. 
§ 38. The loess from Cheyenne was not examined further, nor 
was the loessial soil from this county, but the soil A was. The fine 
sand, with particles from 0.25 to 0.05 millimeter in diameter, the 
silt, the dust and the clay were each analyzed with the following 
results: 
TABLE III.—ANALYSES OF PORTIONS OF “FINE EARTH” OF SOIL 
A. SAMPLE TAKEN TEN INCHES DEEP. 
Fine Sand. Silt. Dust. Clay. 
Silicic Acid.82.024 69.247 58.204 40.389 
Sulfuric Acid. 0.017 0.014 0.100 7.060 
Potassic Oxid. 1.914 2.711 3.166 3.000 
SodicOxid. 1.926 1.851 1.323 3.134 
Ferric Oxid. 3.383 5.425 9.109 7.113 
Aluminic Oxid. 6 737 13.018 19.078 14.607 
Calcic Oxid. 1.746 1.188 1.480 6.059 
Magnesic Oxid. 0.777 1.519 2.648 3.982 
Manganic Oxid (brown). 0.150 0.250 0.190 0.168 
Moisture and Organic Matter.. 0.750 4.118 3.980 14.668 
Total.99.424 99.631 99.278 100.180 
The coarser parts of the soil were not analyzed, for the reasons 
that they are comparatively small in quantity and, on account of 
the large size of their particles, are not subject to those actions 
which liberate plant food to any considerable extent. It might 
have been better for a favorable presentation of results had we 
analyzed them, but there was so little to be gained that we did not 
deem it worth the work. This table shows a very decided differ¬ 
ence in the composition of the parts separated by washing the soil. 
We have no basis of comparison with the loess and other soils. The 
series stands alone, but the results that it exhibits are so pronounced 
and so similar to what we would expect that we have little hesitancy 
in accepting it as proven that there is an accumulation of the 
potash in the finer portions of the soil, and a diminution of the 
silicic acid. 
PROBABLE COURSE OF CHEMICAL CHANGES IN SOIL MASS. 
§ 39. We have here probably a rough presentation of the 
