EDITORIAL OBSERVATIONS. 
227 
be derived partly from these sources and partly from the free 
and gaseous nitrogen existing in the atmosphere, is so im¬ 
portant and interesting a question that the solution of it 
has from time to time engaged the attention of several very 
eminent and distinguished chemists. At a recent meeting 
of the Chemical Society, a paper by Mr. J. Lawes, F.R.S., 
and Dr. Gilbert, F.R.S., was read, in which these gentlemen 
stated that the main object of their experiments, which 
had been carried on for a period of twenty years, was to dis¬ 
cover the source of the nitrogen of vegetation, and especially 
whether free nitrogen could be assimilated by plants.^^ 
After referring to the influence of ammonia, nitric acid, 
and other nitrogen-containing compounds, on certain crops, 
the authors proceed to remark that ^Ghe question as to the 
power of plants to assimilate free nitrogen had been inquired 
into by many investigators. Boussingault’s experiments on 
this point had been made under various conditions; and 
eventually he excluded plants altogether from the external 
air, all the air supplied to the plants being previously washed 
with sulphuric acid, carbonic acid being occasionally supplied 
in addition. He came to the conclusion that plants did not 
assimilate free nitrogen. The experiments of M. Ville, who 
employed an iron case with glass windows to contain his 
plants, led him to an exactly opposite conclusion; there was 
little doubt, however, that in these experiments the increase of 
combined nitrogen was due to the impurity of the distilled 
water supplied to the plants. De Lucca considered that 
ozonized air might efiect the oxidation of free nitrogen, and 
give rise to the formation of nitric acid. 
The question having been left in this conflicting state, the 
authors, with the assistance of Dr. Pugh, had taken it up. 
With respect to the action of ozonized air contained in the 
cells of leaves on nitrogen, it was not probable that ozone 
would be formed during the evolution of oxygen from a plant 
placed in the sun^s rays, since these rays possessed a great 
reducing power; still less could ozone be formed when the 
plant was in the shade, for the oxygen would then be con¬ 
sumed in the oxidation of carbon to form carbonic acid; ozon¬ 
ized air might, however, act on the nitrogen in the air, and 
give rise to the formation of nitric acid. In order to deter¬ 
mine whether plants could assimilate free nitrogen, they em- 
