Nitrogen Fixation 7 
evaporated to dryness at ioo° C. and was finally dried at 160 0 C. 
at which temperature it smelled faintly acid. Incipient decomposi¬ 
tion had taken place. This analysis, as all of those given in this bulle¬ 
tin, presented some difficulties, which every chemist will recognize 
and for this reason moisture, organic matter, etc., have simply been 
given as loss. 
ANALYSIS I. 
WATER SOLUBLE PORTION OF SOIL FROM BLACK SPOTS. 
Laboratory No. 584. 
Per Cent. 
Calcic Sulfate . 
Sodic Chlorid . 
Calcic Nitrate . 
Magnesic Nitrate . 
Sodic Nitrate. 
Potassic Nitrate . 
Silicic Acid .. 
Loss (water, organic matter, etc.) 
46.883 
10.03 3 
12.073 
17.878 
6.03 S 
5.871 
0.3 65 
0.861 
100.000 
The sum of the nitrates is 41.859 or 5.628 per cent of the sur¬ 
face soil. 
This analysis represents a spot possibly 12 feet in diameter 
and almost circular. This is, taken alone, no large area but there 
were a number of these spots all entirely devoid of vegetation, most 
of them black and glistening. There were others occurring under 
different conditions, namely, as round or elliptical, somewhat ele¬ 
vated spots and these, too, were unproductive, but there was a zone 
about the edges of these spots where oats, barley, and wheat grew 
luxuriantly. Many other anomalous things were met with in this 
section of the state. In some places there were no apparent reasons 
why crops should not, but they did not grow. In others there was 
some alkali but the amount of it was less than in others where the 
crops, not necessarily the same crops, were very good. An analysis 
of this alkali showed it to be essentially sodic sulfate with some sodic 
chlorid, about 5.5 per cent of the water soluble, and a relatively 
large amount of potash with some lime and magnesia. Neither 
the quantity nor the composition of this alkali affords a satisfactory 
explanation for the very bad condition of the crops. Only the 
alkali was collected at this place with as little soil as possible, the 
idea being that it was probably the composition and not the quantity 
of the alkali that might be producing the trouble. Twenty per 
cent of it was soluble in water, and ninety per cent of the soluble 
consisted of sulfates, six per cent of chlorids and about three and a 
half per cent of silicic acid, etc. The presence of nitrates was not 
suspected but subsequently it proved that the water soluble portion 
gave a strong reaction for nitric acid. This is suggestive only and 
