INTRODUCTION 



LANT life and animal life are dependent upon 

 the changes which are continually taking 

 place in nature. The laws of nature, as far 

 as they are known, are set forth in the 

 various sciences among which chemistry oc- 

 cupies a prominent place. In every-day life 

 affairs, chemistry takes an important part because it 

 is the science which treats of the composition and uses 

 of substances found in nature. Plant and animal foods 

 which are essential for life are simply mechanical mix- 

 tures of various forms of matter which are constantly 

 undergoing changes and exemplifying the laws of chem- 

 istry. In agriculture, chemistry takes an important 

 part, the term Agricultural Chemistry being applied to 

 that branch of the science which concerns itself with the 

 practical application of the laws of chemistry to the 

 science of agriculture. 



In the cultivation of the soil, production of crops, feed- 

 ing of animals, manufacture of farm products, prepara- 

 tion and use of human foods, and in all life processes 

 numerous chemical changes take place, and it is in part 

 the province of chemistry to investigate these changes so 

 as to assist nature in rendering the plant food of the soil 

 more available, and to produce crops of the highest 

 nutritive value, as well as to indicate ways in which the 

 best possible use can be made of farm products in the 



