No. 7. DEPARTMENT OF AGRICULTURE. 225 



were an expense to the producer. Not content to produce nitro- 

 genous compounds which had already entered the animal kingdom, 

 the chemist discovered the means of calling to his aid innumerable 

 bacteria which have the power of fixing the free nitrogen from the 

 atmosphere. But with all this the chemist was not content, and he 

 has kept on experimenting until to-day it is reported that in Europe 

 and America there are factories iu successful operation fixing the 

 free nitrogen of the atmosphere and making it available for plant 

 growth. If this has really been accomplished, and the chemist has 

 succeeded in transforming the nitrogen of the air into a compound 

 available for plant food and at a slight cost, a new era in farming 

 has arrived. 



PHOSPHORIC ACID. 



When phosphorus was needed for the growth of plants, bones 

 were first used; later the}- were treated with acid to make them 

 quickly available. 



Phosphate rocks were next utilized, and after that certain linings 

 of steel furnaces. Thus we see that the chemist has placed the prin- 

 cipal inorganic fertilizers in the hands of the farmer. 



Whenever he found products whether of nature's make or man's 

 which contained the elements of fertility necessary for plant de- 

 velopment, he devised a method of treatment which would make 

 the food available for plant nutrition. 



Knowing the value of the elements taken up by the plant enables 

 the farmer to grow such crops as will exhaust the soil to the least 

 degree, or if a crop which requires a large amount of a certain fer- 

 tilizer is raised, that ingredient can be supplied in the greatest 

 abundance. 



The study of plant nutrition, which Liebig first investigated, has 

 enabled the farmer to put on his fields just those compounds which 

 will be of the most value to his crops. 



The soil is not a dead mass as was once supposed, but is now 

 known to be teeming with life and must be treated as such. 



FINDING VALUE. 



Chemistry helps the farmer by determining the value of what he 

 produces, uses and loses. In feeding stock it is of great importance 

 for the farmer to know not only what can be used, but what has the 

 greatest feeding and manurial value. It often happens that a 

 farmer can gain by selling part of what he has raised and buying 

 some cheaper feed. The compounds found in feeds of most value 

 are protein, fat and carbo-hydrates. These vary greatly in different 

 feeds as bran, middlings, brewers' grain, linseed m?al, cotton-seed 

 meal, etc., but if the feeder understands the value of each, he can 

 so buy as to get the best results for the least money. 



NEW FEEDS. 



Many new feeds have been placed at the disposal of the farmer 

 through the work of chemistry. When cotton-seed was a nuisance 

 to the man who produced it, and a nuisance to his neighbor as well 

 as to the fish in the creek whore it was usually thrown, the chemist 

 took it, extracted the oil, which immediately became a valuable pro- 

 duct, and produced from the cake a valuable cattle-feed and the 



15—7—1^06, 



