of sewage, (1) in alkaline solutions, (2) in distilled water. 357 
settle, and the clear liquid was drawn from the top. One per cent, 
solutions in pure water were made for immediate analysis, and 
then two 1 per cent, solutions were made, one of which was made 
faintly alkaline with soda solution (called alkaline solution) and 
the other of ammonia-free distilled water (called non-alkaline so- 
lution). The two ammonias, nitrates and nitrites, were estimated 
from time to time after incubating for the several times mentioned 
in the following tables. The figures represent parts per 100,000. 
Incubation 
Alkaline solution 
Free NH 3 
Albumin- 
oid NH 3 
Total NH 3 
Nitrates 
Nitrites 
Sample I. 
Initial analysis 
0-040 
0-700 
0-740 
0-040 
nil 
2 days 
0-304 
0-320 
0-624 
0-008 
trace 
1 3 days 
0-464 
0-560 
1-024 
0-020 
nil 
52 days 
0-704 
0-160 
0-864 
0-023 
33 
Sample II. 
Initial analysis 
0-524 
1-040 
1-564 
0-069 
nil 
3 days 
0-365 
0-400 
0-765 
0-014 
3 ) 
1 7 days 
0-636 
0-500 
1-136 
0-019 
33 
37 days 
0-160 
0-400 
0-560 
0-029 
33 
Incubation 
Non-alkaline solution 
Free NH 3 
Albumin- 
oid nh 3 
Total NH S 
Nitrates 
Nitrites 
Sample I. 
Initial analysis 
0-040 
0-700 
0-740 
0-040 
nil 
2 clays 
0-370 
0-560 
0-930 
0098 
trace 
1 3 days 
0-384 
0-240 
0-624 
0-035 
nil 
52 days 
0-264 
0-440 
0-704 
0-088 
33 
Sample II. 
Initial analysis 
0-524 
1-040 
1-564 
0-069 
nil 
3 days 
0-325 
0-640 
0-965 
0-079 
33 
17 days 
0-369 
0-800 
1-169 
0-039 
33 
37 days 
nil 
0-160 
0160 
0-092 
3 ) 
The more noticeable facts in the above tables are (1) smaller 
quantities of nitrates in the alkaline solutions than in the non- 
alkaline ; (2) a larger comparative increase of free ammonia in the 
24 
VOL. XIV. PT. IV. 
