PREFACE 



Since the time of Liebig, agriculture in its many phases has 

 profited from the science of chemistry. A store of useful infor- 

 mation has been made available through the study of the elements 

 and compounds fundamentally concerned in the art of agricul- 

 ture. It is reasonable to expect that this art will in the future 

 be enriched from the same source. 



This little book was written in the interest of the young farmer 

 and the student beginning the study of agricultural chemistry. 

 No extended knowledge of chemistry is required for its under- 

 standing. It makes no special appeal to the chemist. It is a 

 survey of the general field of chemistry applied to agriculture, 

 with the emphasis always placed on the applied side. 



Throughout the book we have striven to express safe views 

 rather than to echo the most recent. Hypotheses and theories 

 have not been discussed. We have attempted to give, in general, 

 only well tested and established principles. Formulas and re- 

 cipes have been avoided as far as possible. While we recognize 

 their helpfulness, nevertheless, they are as yet but imperfect 

 expressions of relations not fully understood. 



The authors have drawn freely from various publications, en- 

 deavoring to bring together from scattered sources the materials 

 essential to such a work on agricultural chemistry. In this re- 

 gard we are especially indebted to the works of Ingle, Warington, 

 Storer, Voorhees, Vivian, Jordan and others, all of which have 

 aided greatly in the preparation of this work. 



