448 
ME. J. B. LAWES, BE. GILBEET, Al^D BE. PUGH ON 
A. — M. Boussingault’s Experiments. 
1. M. Boussingault’s ex;periments in 1837 and 1838, in which the plants were allowed 
free access of air, hut were ^protected from rain and dust. 
In 1837* Boussingault grew, in burnt soil, watered with distilled water, and with 
the access of free air, a pot of Trifolium for two months, and another for three months ; 
also a pot of Wheat for tAvo months, and another for three months. 
The total Nitrogen in the seeds sown in the two experiments with Trifolium, amounted 
to 0-224 gramme. The Nitrogen in the produce, soil, pot, &c., amounted to 0-276 
gramme. There was a gain, therefore, of 0-052 gramme of Nitrogen = nearly 20 per 
cent, of the total Nitrogen of the products. The development of vegetable matter, 
implying, of course, the assimilation of carbon, hydrogen, and oxygen, was, however, 
in a much greater proportion ; the dry matter of the produce in the two experiments 
amounting to nearly three times that of the seed sown. 
In the two experiments Avith Wheat, the total Nitrogen in the seed was estimated at 
0-100 gramme. The Nitrogen in the products was exactly the same amount. In the 
case of the Wheat, there Avas, therefore, no gain of Nitrogen indicated. Nevertheless 
the dry matter of the produce amounted to nearly double that of the seed. 
In 1838f, Boussingault, in a similar manner, soAved Peas containing 0-046 gramme 
Nitrogen. The plants obtained; yielded flowers and ripe seed, and their dry matter 
Avas more than four times as much as that of the seed soAvn. The Nitrogen of the total 
products amounted to 0-101 gramme. Here again, therefore, the Leguminous plants 
seemed to gain Nitrogen from some undetermined source. 
Boussingault made experiments in the same year (1838), with Trifolium, and with 
Oats. In these cases, he commenced with carefully selected plants instead of with seeds. 
The Trifolium nearly trebled its total vegetable matter during growth ; and it gained 
0-023 gramme of Nitrogen out of 0-056 gramme in the total products. The Oat, on the 
other hand, indicated only 0-053 gramme Nitrogen in the total products, Avhilst it Avas 
estimated that there Avas 0-059 gramme contained in the plants taken for the experi- 
ment. The total vegetable matter was, however, doubled. 
The substance of M. Boussingault’s conclusions from the above experimental results, 
may be stated as follows : — That under several conditions, certain plants seem adapted 
to take up the Nitrogen in the atmosphere ; but that it was still a question, under Avhat 
cu-cumstances, and in what state, the Nitrogen AA^as fixed in the plants. He submitted 
— that the Nitrogen might enter directly into the organism of the plant, provided its 
green parts Avere adapted to fix it; that it might be conveyed into the plant in the 
aerated water taken up by its roots ; that, as some physicists suppose, there may exist 
in the atmosphere an infinitely small amount of ammoniacal vapour. He further 
suggested that the gain of Nitrogen beyond that supplied in manure, which he had 
observed in agricultural production on the large scale, and which he thought evidently 
* Arm. de Chim. et de Phys. ser. 2. tome Lsvii. 1838. f Ibid, tome Lxii. 
