THE SOIJECES OE THE NITEOGEN OE VEGETATION, ETC. 
455 
in the soil an amount of carbonate of potash very nearly corresponding in potash to 
the amount of nitrate of potash which would represent the observed loss of Nitrogen. 
He concluded that nitrate had been decomposed in the soil, by the organic matter of 
the debris of the seeds and of the roots, and that Nitrogen had been evolved. If we 
clearly understand this explanation of the loss of Nitrogen of the nitrate, we would 
suggest that it would seem to require for its validity that the plant should have assimi- 
lated potash from the nitrate exactly corresponding in amount to the Nitrogen it fixed 
from the same source. 
From the results of these experiments with nitrate, Boussixgault drew the following 
conclusions : — 
1. That there was no assimilation of free Nitrogen. 
2. That there was a loss of supplied Nitrogen, either from the soil, or by the plant. 
3. That, in the two cases, the amount of carbon assimilated bore a close relation to 
that of the Nitrogen taken up by the plant. 
It is seen, then, that the results of the laborious investigations of Boussingault, 
extending at intervals over a period of more than twenty years, have led him to con- 
clude that, neither Leguminous plants, nor the others experimented upon, were able, 
either when their supplies of combined Nitrogen were limited to that contained in the 
seed sown, or when their 'vigour of growth was stimulated by artificial supplies of com- 
bined Nitrogen, to assimilate the free or uncombined Nitrogen of the atmosphere. 
B. — M. G. Ville’s Expeeimexts*. 
1. M. G. Ville’s determinations of the Ammonia in the atmosgAiere. 
M. G. ViLLE, of Paris, commenced his investigations, on the subject of the assimilation 
of Nitrogen by plants, in 1849. He first sought to determine the proportion of 
Ammonia in the atmosphere. To this end, he aspired known quantities of air through 
acid, and determined the amount of ammonia absorbed. He operated upon very much 
larger volumes than previous experimenters had done. His results show, moreover, a 
much smaller proportion of ammonia in the air than those of others. 
The air of Paris, during part of 1849 and part of 1850, gave a mean of only 0'0237 
part by weight of ammonia, to 1,000,000 parts by weight, of air; and that of the 
suburbs of Paris, during some period of 1852, gave 0‘0211 parts of ammonia, to 
1,000,000 parts of air. 
2. M. G. Ville’s general plan of experimenting on the guestion of the assimilation 
of Nitrogen hy plants. 
M. G. ViLLE employed specially-made porous flower-pots, and used, as soil, washed 
* Eecherclies Experimentales siir la V^etation, par M. Geokqes Ville. Paris, 1853. 
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