OITESTION OF THE SOURCES OF THE NITROGEN OF VEGETATION. f")! 
The nitrogen was determined in seed, in the products of growth, and in tlie soils 
before and after growth. The seeds and plants were dried at 50° C. for analysis, and 
it was found that the lupin seeds contained an average of O'OOO gram, nitrogen per 
seed, and that 20 incarnate clover seeds contained 0'003 gram of nitrogen. 
Summary of Dr. Frank’s results in the summer of 1885. 
Nitrogen. 
Per cent 
in soils. 
Total in 
soil and 
seed at 
commence- 
■ ment. 
In the 
plants. 
Total in 
soil and 
plants at 
conclusion. 
Gain or loss on the 
Before 
experi¬ 
ment. 
After 
experi¬ 
ment. 
Actual, 
Per cent. 
Per cent. 
Per cent. 
Grams. 
Grams. 
Grams. 
Gr-jms. 
Per cent. 
1. Earthen evlinder withoiit plant 
0-0957 
0-0907 
20-5755 
— 
19-5112 
-1-0643 
- 5-1 
2. Glass cylinder without plant 
0-0957 
0-0837 
9-2589 
— 
8-0979 
-1-1610 
-12-5 
o. Glass evlinder without plant 
0-0957 
0-0832 
7-1775 
6-2400 
-0-9375 
- 8-69 
4. j 
Earthen cylinder with 31 
lupin seeds.f 
0-0957 
0-1065 
20-5547 
0-8208 
23-6758 
+ 3-1211 
+ 15-2 
5. G 
lass cylinder with 1 lupin seed 
0-0957 
0-0992 
9-0373 
0-1138 
9-4781 
+ 0-4408 
+ 4-87 
' Glass cylinder with 1 lupin, 1 
6. J 
and 20 incarnate clover > 
0-0957 
0-0854 
8-29039 
0-2295 
7-6169 
-0-67349 
- 8-08 
seeds.J 
7. Glass cylinder with 2 lupin seeds 
0-0957 
0-0893 
8-8032 
0-0274 
8-22.51 
-0-5781 
- 6-56 
It is seen that the actual amounts of nitrogen involved were large, being about 
20 grams in the experiments in the wider vessels, and nearly half as much in those in 
the narrower vessels. The losses were in some cases about, or more than, a gram; 
and one of the two gains amounted to more than 3 grams. 
In each of the three experiments without a plant (Nos. 1, 2, and 3), there was a 
loss of nitrogen. Frank states that it was not as nitric acid, which either diminished 
but little, or increased, there being no plant to take it up. Nor was it as ammonia, 
as a direct experiment with a rich peaty soil, enclosed under a luted bell jar, and 
ammonia free air passed through it, showed very little ammonia evolved. He points 
out that the more imperfect the ventilation of the soil, the less was the gain; and he 
considers it probable that in the absence of ventilation the evolution of free nitrogen 
would be enhanced. In fact the losses were greater in experiments 2 and 3 with 
vessels 80 cm. (= 31’5 in.) deep, and only 11 cm. (= 4'3 in.) wide, than in No. 1 
with a width of 17'5 cm. (= 6'9 in,). 
It is indeed obvious that, with vessels so narrow and deep, and closed at the 
bottom, as according to the description we conclude they were,^' and with no plant to 
cause evaporation, and with consequently very little aeration, the conditions would be 
favourable for the evolution of free nitrogen, and the more so in the narrower vessels. 
In fact it may be doubted whether, if there had been holes at the bottom of the 
* We have since ascertained that the vessels were closed at the bottom. 
