iv PREFACE 



farmer to know their composition, and how much of each 

 element they contain. This analysis serves a two-fold 

 purpose: First, the composition of a plant shows what 

 elements, and what quantity of each, have been removed 

 from the soil. This, in turn, determines what the soil 

 must contain to grow plants in a healthy condition. Second, 

 in feeding vegetable products to livestock, the composition 

 of these vegetables must be known in order that the rations 

 may be compounded correctly. 



Furthermore, chemistry explains how plants grow and 

 are nourished. It shows the kind and the quantity of 

 foods which plants require at various stages of their growth, 

 and this guides the farmer in properly handling his crops. 

 It teaches what purposes the different elements in the food 

 supplied serve in animal economy and how the best results 

 in animal feeding may be obtained with the least outlay 

 of time, labor, and expense. 



The purpose of this text is to furnish the knowledge of 

 the fundamentals of chemistry required for intelligent 

 agriculture and to apply this knowledge to the art of 

 agriculture and to the problems of the agriculturist. No 

 attempt has been made to limit its scope to the study of 

 soils, fertilizers, and manures, although these subjects are 

 given careful consideration. In addition, such subjects as 

 feeds, nutrition, sanitary water, boiler water, and insecti- 

 cides, subjects in which not only the farmer, but the sub- 

 urban resident is interested are discussed in as non- 

 technical language as possible. 



The student of this book is urgently requested to make 

 a careful study of the first chapters; for in them has been 

 given in as concise and elementary form as is practicable 

 the chemistry applied in the chapters which follow. Each 

 succeeding chapter requires a knowledge of the preceding 

 chapter, consequently they should be studied in sequence. 



The author wishes to express here his indebtedness 

 to Professor Charles M. Allen, Pratt Institute, for carefu) 



