The Fixation of Nitrogen. 21 
foot were taken as one sample and gave 4.27 percent soluble in 
water. 
ANALYSES 
XVI 
XVII 
Water-Soluble 
Fabratory 
No. 632 
First Foot 
Percent 
Water-Soluble 
Fabratory 
No. 633 
Second and 
Third Foot 
Percent 
Calcic sulfate . 41.882 42.122 
Magnesic sulfate . 8.747 18.397 
Sodic sulfate . 10.847 5.747 
Sodic chlorid . 34.014 28.019 
Sodic silicate . 1.276 1.479 
Manganic oxid .. 0.070 
Ignition ..'. 3.234 4.184 
100.000 
100.000 
These water-soluble portions were tested for nitric acid and 
there was not enough present to give a reaction with ferrous sul¬ 
fate and sulfuric acid. That the water-soluble should be made up 
so largely of calcic sulfate is what one would expect, because this 
salt, as the mineral gypsum, can be seen forming veinlets and 
small aggregations throughout the mass of the soil. This is the 
case to a greater extent in the second and third than in the first 
foot. The quantity of sodic chlorid is larger than usual but is still 
within the limits of tolerance for almost all plants. 
ANALYSES 
Sand . 
Silicic acid (sol.) . 
Sulfuric acid . 
Chlorin . 
Phosphoric acid. 
Carbonic acid . 
Lime . 
Magnesia . 
Sodic oxid . 
Potassic oxid . 
Ferric oxid. 
Aluminic oxid . 
Manganic oxid . 
Water expelled at 100° 
Ignition ... 
Sum. 
Oxygen equiv. to chlorin 
Total. 
XVIII 
XIX 
Soil 
Soil 
laboratory 
laboratory 
No. 632 
No. 633 
First Foot 
Second and 
Third Foot 
Percent 
Percent 
48.951 
47.747 
22.377 
17.945 
0.708 
3.194 
0.387 
0.599 
0.156 
0.217 
3.968 
3.709 
4.624 
5.877 
2.650 
2.864 
0.740 
1.033 
1.082 
1.356 
4.344 
3.374 
5.286 
7.405 
0.168 
0.675 
1.707 
2.933 
2.986 
(1.207) 
100.134 
100.135 
0.087 
0.135 
100.047 
100.000 
Another soil in which the conditions were worse even than 
in the preceding is represented by the next sample. This ground 
