302 AMMONIA AND NITKIC ACID. 



which the farmer lays out in its purchase will always 

 ensure an adequate return. 



Now, when his common sense tells him that such a 

 supposition is impossible, and that he has only to open 

 his eyes to observe by innumerable facts that ammonia 

 is no exception to other nutritive substances, he will of 

 himself come to the conclusion that the inactivity of 

 the great mass of nitrogen in his field is not due to any 

 condition peculiar to itself, which science can neither 

 investigate nor explain, but that it is inactive, just as 

 phosphoric acid, potash, lime, magnesia, silicic acid, and 

 iron, are inactive, when there is wanting in the ground 

 one of the conditions necessary to make 'them available. 



The theory that by far the greater portion of the 

 nitrogen in the ground is incapable of serving for the 

 nutrition of plants, cannot be proved by the fact that 

 the crops do not bear any proportion to the amount of 

 nitrogen in the soil ; for were this the case, then all 

 soils must be equally abundant in all other conditions 

 for the growth of plants, and everywhere possess the 

 same geological and mechanical condition. But this 

 assumption is impossible, for on the whole surface of 

 the globe there are not two districts in which the soils 

 are identical in these respects. 



This theory must be strenuously opposed, not only 

 because it is false generally, and that it has never yet 

 been proved to be true even in a single case, but still 

 more on account of the pernicious influence which it 

 exercises upon the practice of the farmer. For since it 

 induces him to suppose that it is impossible to give the 

 necessary efficacy to the store of nitrogen in his land, 

 he will never think even of attempting to do so. Being 

 convinced beforehand that he need not try to raise the 

 treasure buried in his field, he never even makes the 

 attempt. 



Since the exact observation made in the cultivation 

 of entire countries and divisions of the globe for centu- 

 ries past, and also well-established facts, make it prob- 

 able that a source of nitrogenous food exists, which en- 

 sures annually to a cultivated field without the husband- 



