464 MR. J. B. LAWES, DR. GILBERT, AND DR. PUGH ON 
that supplied in the combined form, was observed to be the largest in some of the cases 
where no nitrogenous manure was employed, and where the total amount of combined 
Nitrogen within the reach of the plants was confined to a few milligrammes only, con- 
tained in the original young plants or seeds that were planted. In some such instances, 
the amount of combined Nitrogen found in the products was about forty times as much 
as was supplied. In other cases, the assimilation of free nitrogen only seemed to take 
place when the activity, and stage of growth, of the plants, had been forced beyond a 
certain point by the use of considerable amounts of nitrogenous manure. 
Results and conclusions so astonishingly conflicting as those of M. BoussincauLr and 
M. G. VILLE, have naturally incited others, either to investigate anew, or to seek, in 
the conditions provided in their experiments, for some explanation of the discordance. 
Before entering upon the consideration of our own experiments bearing upon the points 
in question, it will be desirable to add to the foregoing review a brief notice of the 
labours, or opinions, of these other experimenters or arbitrators. 
C.—M. Miner’s Experiments *. 
In 1851, M. Mine made some experiments in reference to the assimilation of Nitrogen 
by plants. He seems to assume that Boussineaut had concluded from his experiments 
that the free Nitrogen of the atmosphere was appropriated by plants; and he refers to 
the experiments of M.G. VILLE as confirmatory of such a view. M.Minz made three 
sets of experiments in reference to this question. 
1. He grew Wheat and Peas, respectively, in powdered glass as soil, allowing them 
contact with common air, and watering them with pure water. The Wheat increased 
in Nitrogen in amount equal to one-fourth of that contained in the seed sown; whilst 
its carbon, hydrogen, and oxygen were double those of the seed. The Pea-plants 
doubled the carbon, oxygen, and hydrogen of the seed sown, and their Nitrogen. was 
threefold that of the seed. 
2. Lentils, Peas, Haricots, Beans, Wheat, Rye, and Oats were grown in a sterile 
matrix under a bell-glass. They were respectively supplied with’ an atmosphere of 
known composition, and with acetate of ammonia in the soil. The plants increased in 
Nitrogen, and the ammonia in the soil diminished; but the free Nitrogen of the air was 
not perceptibly affected. 
3. This series of experiments was in every way similar to the second, with the excep- 
tion that the Nitrogen of the air was replaced by hydrogen. The plants flourished, 
and took up some of the acetate of ammonia. 
M. Mivz concludes that plants do not appropriate the free Nitrogen of the air. 
D.—M. Roy’s VIEWS ON THE SUBJECT OF THE ASSIMILATION OF NITROGEN BY PLANTS}. 
M. Roy gave a paper on this subject in 1854. His supposition was that carbonate of 
ammonia constituted the chief source of Nitrogen to plants. Leguminous plants, he 
* Compt. Rend. xxxii. + Ibid. xxxix. 
