84 
Sill J. B. LAWBS AND PROFESSOR J. H. GILBERT ON THE 
rich garden surface soil, mixed with more or less sand, or quartz, or both. The plants 
grown were lupins, hemp, and haricots ; in some cases in free, and in others in confined 
air. In the latter cases, the materials were put into a large glass balloon, or carboy, 
moistened with pure distilled water, the seed sown, and then the whole perfectly 
closed from the outer air by means of caoutchouc, arrangement being made, however, 
for the supply of carbonic acid. 
In the experiment with lupins in confined air, the largest amount of the rich 
soil was used, and the result was so striking, that Boussingault repeated it the next 
year, 1859,^ when he obtained an almost identical result. In no other case was there 
anything like the same amount of gam of nitrogen, and we must only refer in any 
detail to the conditions and the results of these two experiments. They were as 
follows :— 
Soil, &c. 
Nitrogen. 
Date. 
Plant. 
Air. 
At commencement. 
At conclusion. 
Soil. 
Sand. 
Quartz. 
Ash. 
In 
soil. 
In 
seed. 
Total. 
\u 
soil. 
In 
plant. 
Total. 
Gain. 
1858 
1859 
Lupin 
Lupin 
Confined 
Confined 
grams. 
130 
130 
grams. 
1000 
720 
grams. 
500 
150 
grams. 
0-2 
01 
grams. 
•3393 
•3380 
grams. 
•0204 
•0200 
grams. 
•3597 
•3580 
grams. 
•4055 
•3834 
grams. 
•0246 
•0417 
grams. 
•4311 
•4251 
grams. 
+ •0714 
+ •0671 
It should be stated that, taking the mean of 7 determinations by the soda-lime 
method, the rich garden soil used contained 0'261 per cent, of nitrogen. This 
Boussingault calculated would correspond to 11,310 kilog. nitrogen per hectare' 
(= 10,098 lbs. per acre), one-third of a metre deep. He also determiued the 
amounts of ammonia, nitric acid, and carbon, in the soil; and he concluded that 
the nitrogen, beyond the small amount existing as ammonia or nitric acid, was in 
combination as organic matter. In fact it existed in organic detritus, and especially 
in a black substance which he observed by the microscope. 
Referring to the figures, it is seen that in the experiment in 1858 there was a gain 
of 0'0714 gram nitrogen, upon a total of 0’3597 supplied in soil and seed. Further, 
calculation shows that, of the total gain 0‘0672 gram was in the soil, and only 
0'0042 gram in the plant, notwithstanding that the original soil contained 0’3393 gram 
nitrogen. Boussingault remarks that the fertilising matters in the soil had thus 
scarcely taken any part in the growth ; the conclusion being that it was only the 
nitrogen that existed as, or was transformed into, ammonia or nitric acid, that was 
available. He further remarks, that it was impossible, that anything like the amount 
of excess of nitrogen in the soil could be due to the debris of the vegetable matter of 
the lupin, roots, &c. He adds ;— It is the soil and not the ^olant ivhich has fixed 
the nitrogen ; and one such result can only he admitted if conjlrmed hy future 
experiments. 
* ‘ Agvouomie, etc.,’ p. 329. 
