COST OF AMMONIA. 325 



source of ammonia in giiano will be exhausted ; that we 

 have no prospect of discovering a new and richer soiu'ce ; 

 that the annual increase of population, not only in 

 England but in all European countries, is more than 1 

 per cent. ; and, finally, that in proportion to the increase 

 in the population in the United States, Hungary, &c., a 

 corresponding diminution must follow in the exportation 

 of corn from those countries. From these considerations 

 the hope of augmenting the crops of a country by the 

 importation of ammonia must appear utterly vain, 



Li Germany, a pound of Avheat costs at present 

 4 kreutzers (l|rf.); a pound of sulphate of ammonia, 

 9 kiTutzers (34fZ.) ; and if it were possible with a pound 

 of this salt, added to our ordinary manures, to produce 

 2 poimds more of wheat, then for every outlay of one 

 florin (2s.) in money, the German farmer would receive 

 53 kreutzers (Is. 9^.) in corn. This relation of outlay 

 to income is evidently well known in practice, for up to 

 this moment salts of ammonia have nowhere come into 

 general use ; and though many manufacturers of manure 

 add a certain quantity of ammonia to their productions, 

 this is chiefly to humour the fancy of formers for this 

 substance ; but none of them can tell what advantage 

 results from this addition. This prejudice will soon dis- 

 appear of itself, when farmers have learned to make a 

 proper use of the nitrogenous food which nature supplies 

 spontaneously to the land without any aid on their part. 



The abundant supply of nitrogenous food in the soil, 

 the increase of the same in well-cultivated ground, the 

 examination of rain-water and of the atmosphere, all 

 facts observed in cultivation in general, prove that, even 

 wdth the highest system of forming, the soil is not ex- 

 hausted in its store of nitrogenous food, and that conse- 

 quently there is a circulation of nitrogen, like that of 



