206 SOURCES OF AMMONIA. 



Now, it may be asked, Is there no means of increasing the 

 amount of ammonia which exists in the atmosphere, as well as 

 in the form of plants and animals, and which we shall assume to 

 be a limited quantity ? This question may be repeated in another 

 form, viz. Whether there exist undoubted facts for the opinion 

 that the nitrogen of the air possesses, under any condition, the 

 power of assuming the form of ammonia, or of any other com- 

 pound of nitrogen ? Besides nitric acid and ammonia, we do 

 not know any other compounds of nitrogen, except those exist- 

 ing in plants and animals, or which may be prepared from them. 

 With the exception of these compounds, nitrogen exists only in 

 the form of a gas, which has been recognised as one of the prin- 

 cipal constituents of air. 



An ignorance of the proper sources whence vegetation receiv- 

 ed its nitrogen, led philosophers long since to the opinion, that 

 plants must possess the power, in some way or another, of appro- 

 priating the nitrogen of the air in their vital processes. In fact, 

 until it was known that ammonia formed a constituent of the air, 

 there was scarcely any reason to doubt this power of plants ; for 

 how otherwise were wild plants to obtain the nitrogen of their 

 azotized constituents ? 



But ammonia was known and considered only as a product of 

 the destruction and decomposition of the organism. The pro- 

 duction and formation of ammonia presupposed the existence of 

 plants or animals. Hence there have arisen two views respect- 

 ing the origin of ammonia, the correctness of which we have as 

 little means of establishing by decisive evidence, as we have of 

 answering the questions — Whether the hen existed before the 

 egg, or the egg before the hen ; or whether water was first creat- 

 ed as water, or as hydrogen and oxygen ? We have sufficient 

 reason to believe that the vegetable preceded the animal kingdom ; 

 and we assume, that before plants were formed, the conditions 

 essential for their life and increase must have existed ; and that 

 then, as well as now, ammonia must have been a constituent of 

 the air ; and that the destruction of plants did not precede the 

 formation of ammonia. Now, it is obvious that if the same 

 causes now continue in action, as those which effected the forma- 

 tion of ammonia at the commencement of vegetation,— if their 



