9 
inally present in the soil. This was deducted from the amounts 
found. 
The basic nitrogen was determined by precipitation with phospho- 
tungstic acid in water solutions obtained by filtering the residue left 
after the distillation with magnesium oxid. As shown by previous 
investigators, 1 the nitrogen thus obtained in this precipitate occurs 
largely in the form of diamino acids. Purins, alkaloids, etc., may 
also be precipitated by phosphotungstic acid, and, therefore, if pres- 
ent, would be contained in this group. The nonbasic nitrogen was 
determined by subtracting the sum of the other two groups from the 
total nitrogen dissolved. While this group is now referred to by 
some investigators as monamino acids, Jodidi and Robinson have 
each brought forth evidence that it is not made up wholly of mon- 
amino acids. Just what other bodies occur in this group is not yet 
known. The results obtained, calculated as in all other cases in 
this bulletin on the water-free basis, are given in the following table: 
Organic nitrogen of Hawaiian soils. 
[Soluble in hydrochloric acid.] 
Per cent 
of total 
nitrogen. 
Per cent of the soil. 
Per cent of nitrogen in solution. 
Soil No. 
Amid. 
Basic 
nitrogen. 
Nonbasic 
nitrogen. 
Total. 
Amid. 
Basic. 
Nonbasic. 
379 
71.96 
72.59 
67.51 
91.80 
90.91 
88.52 
80.42 
84.62 
91.22 
0.095 
.141 
.074 
.024 
.054 
.042 
.225 
.042 
.079 
0.030 
.028 
.033 
.012 
.020 
.017 
.097 
.019 
.055 
0.300 
.368 
.131 
.075 
.124 
.131 
.663 
.099 
.276 
0.426 
.559 
.239 
.112 
.200 
.193 
.998 
.165 
.416 
22.30 
24.79 
30.96 
21.43 
27.00 
21.76 
22.55 
25.45 
18.99 
7.04 
5.01 
13.81 
10.71 
10.00 
8.81 
9.72 
11.51 
13.22 
70.42 
428 
66.27 
447 
54.82 
292 
66.96 
343 
62.00 
345 
67.88 
347 
66.43 
405 
60.00 
406 
66.35 
23.91 
9.98 
64.57 
The above table shows that there is considerable variation in the 
amounts of soluble nitrogen in different soils. In soil No. 447 only 
67.51 per cent of the total nitrogen was dissolved, while No. 292 
yielded 91.80 per cent. Concerning the insoluble nitrogen very little 
is known. 
AMIDS. 
Upon distilling the solutions after making them alkaline with mag- 
nesium oxid approximately 25 per cent of the nitrogen in solution was 
obtained in the form of ammonia, here referred to as amid nitrogen, 
and all the soils studied, with the exception of Nos. 447, 343, and 406, 
yielded approximately the same relative amounts of nitrogen as 
ammonia. It Is of interest to note that the amids constitute a 
33297°— 14- 
1 Jodidi, loc. cit.; Robinson, loc. cit. 
