298 MIMONIA AND NITEIC ACID. 



realised. The salts of ammonia were so far from exerting 

 any influence in augmenting the corn-crop, that they 

 diminished it in every experiment. In the crop of straw 

 there was a small increase. 



In these cases the salts of ammonia had not enlarged 

 the corn crop, but had produced the opposite effect from 

 guano, by which corn crops are generally augmented. 



These experiments cannot, however, be regarded as 

 decisive proofs against the view of the action of ammonia, 

 because a comparative experiment with guano was not 

 made at the same time and place. It is not impossible, 

 that upon this particular field guano might have produced 

 the same results. Some years later, Lawes and Gilbert 

 published a series of investigations, which seemed to 

 establish the operative power of ammonia, or rather of 

 salts of ammonia. These investigations were intended to 

 show, that the incombustible nutritive substances of wheat 

 were not, of themselves, sufficient to enliance the fertility 

 of a field, but that the crop of corn and straw stood 

 rather in proportion to the supply of ammonia. In fact, 

 that increased crops could be obtained by salts of am- 

 monia alone, inasmuch as nitrogenous manm^es were pecu- 

 liarly adapted for the cultivation of wheat. 



The experiments of Messrs. Lawes and Gilbert are very 

 far, indeed, from proving the conclusions which they wish 

 to draw ; they estabhsh rather the fact that these gentle- 

 men have not the shghtest notion of what is meant by 

 argument or proof. 



They did not attempt to discover whether salts of 

 ammonia alone could produce from one portion of a field 

 continuous larger crops than were yielded by an un- 

 maniu-ed portion of the same field. 



Neither did they attempt to discover what crops would 

 be j-ielded by an equal plot of ground by manuring with 



