166 
among the most powerful of all the agents in promoting vegetation. It 
is sufficient, for instance, to bear in mind that in the productive hus¬ 
bandry of Flanders, putrid urine is the manure that is employed with 
the greatest success ; but we have seen that by putrefaction the urea* of 
the urine is entirely changed into carbonate of ammonia. The fields of 
Flanders are consequently fertilized with a solution of carbonate of am¬ 
monia in water.” 
Baron Liebig, although almost an enthusiast in favor of the efficacy of 
inorganic manures, and although he maintains that plants can find an 
adequate supply of nitrogen in rain water and the atmosphere, neverthe¬ 
less holds the following views, according to the Handbuch fur Augehense 
Landwirthe, (see Patent Office Report, 1847, p.223,) “ that plants re¬ 
ceive nitrogen from the ammonia of rain water, and this ammonia is de¬ 
rived not only from the putrefaction of organic bodies, but it is also in 
part a constituent part of the body of the globe. Animal manures oper¬ 
ate only by the formation of ammonia.” We cannot but think that the 
Baron in maintaining the intervention of the atmosphere in the assimila¬ 
tion of nitrogen, and in claiming that, animal manures act only by means 
of the atmosphere, had in view the support of his favorite theory of in¬ 
organic manures, which is, “ that the crops on a field diminish or in¬ 
crease in exact proportion to the diminution or increase of the mineral 
substances conveyed to it in the manure.” 
J. F. W. Johnston also, in his Agricultural Chemistry, sums up his re¬ 
marks on this subject in the following words, “ thus the immediate and 
visible effect of different vegetable substances in the same state is mea¬ 
sured by the relative quantities of nitrogen they contain— t\\e\r permanent 
effects by the relative quantities of inorganic and carbonaceous matters.” 
This is taking the middle ground between the French and German chem¬ 
ists, but still he acknowledges the principle which is sufficient for our 
purpose. 
* Urea is composed of Carbon. 20. 
Hydrogen. 6.6 
Oxygen. 26.7 
Nitrogen. 46.7 
100.0 
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