FARADAY'S EXPERIMENTS. 2*3 



All observations in our times lead to the conclusion that the 

 nitrogen of the air does not possess the property of being con- 

 verted into ammonia ; and, whatever reasons there may exist for 

 the probability of this conversion, we are by no means entitled 

 to elevate to the rank of a principle the mere opinion that a part 

 of the nitrogen of plants arises from this source, as it is an hy- 

 pothesis standing in complete contradiction to all the knowledge 

 which we have yet attained. 



All experiments which appear to piove that the nitrogen of the 

 air becomes fixed in the organism of certain plants, — that peas 

 and beans, for example, vegetating in a soil perfectly destitute of 

 animal matters, must possess the power of appropriating the ni- 

 trogen of the atmosphere, — cannot now have the smallest value, 

 when it is known that the air contains ammonia as a constant 

 ingredient. It must be recollected that these experiments were 

 instituted in districts in which the atmosphere is much richer in 

 ammonia than in the free fields, and that the distilled water, with 

 which the plants were treated, was obtained from spring-water, 

 and contained a much larger quantity of carbonate of ammonia 

 than rain-water. Hence, there is no reason to ascribe the in 

 crease of nitrogen in the seeds, leaves, and stems, to a source 

 which was only imagined to exist, because the quantity of am- 

 monia in the water and air was not considered, and the founda< 

 tion, therefore, of the true explanation was altogether wanting. 



Chemical experiments have shown that ammonia is not only the 

 product of the decay and putrefaction of animal bodies, but that 

 it is also capable of being generated in many chemical processes, 

 when nitrogen, at the moment of its liberation from compounds 

 containing it, is offered to hydrogen ; in such a case, they unite 

 together and form ammonia. 



Compound gases containing nitrogen as a constituent (cyanogen, 

 nitric oxides, nitrous oxides), are converted into ammonia when 

 they are mixed and conducted ever spongy platinum heated to 

 redness (Kuhlmann), or over peroxide of iron (Reiset). 



When steam is conducted over red-hot wood charcoal contain- 

 ing nitrogen, there is obtained, among other products, hydrocyanic 

 acid, which is converted into ammonia and formic acid when 

 treated with alkalies. 



