12 



vegetation; but without the nitrogen, only a very 

 feeble growth could be obtained # 



The fact is, Liebig saw a great light illuminating 

 the heavens of his beloved science, and not having 

 the patient research of less gifted minds, he uttered 

 premature thoughts, grand in their conception, but 

 too deeply colored by his excited imagination. He 

 discovered, what seemed to him, a vast store house 

 of ammonia in the air, and supposing that all plants 

 could absorb, through their leaves, from that source 

 alone, all the nitrogen they needed, he made a posi- 

 tive declaration that there is no necessity of collect- 

 ing the elements of the atmosphere in the soil. 



Now, we regard this question as> settled, that the 

 nitrogen of the air, though all-sufficient, must in 

 some way be oxidized and become a constituent of 

 the earth, before plants can receive and assimilate it, 

 and make it a part oi their structure. 



CHAPTER II. 



COVERING THE SOIL. 



When green crops are raised to improve the land. 

 it is not indispensable that they should be plowed in 

 to accomplish this object. You need not turn them 

 in, till you are under the necessity of doing it, to 

 prepare the ground for a future crop. But if the 

 greendressing should be Hungarian millet, or white 

 mustard or any thing that might seed the ground at 

 an improper time, you can either plow it in, or cut it 



See a beautiful plate in illustration of this subject, in American Agricul- 

 turist, March, 1876. 



