X AUTHORS 1 PREFACE 



follow the entire text, in which event we think it will be 

 found possible to omit certain sections and yet have a 

 connected treatment of the subject. On the other hand, 

 very little attempt has been made to supply illustrations 

 of the principles which are explained. Such illustrations 

 and amplifications are left to be added by the teacher as 

 local conditions and interests may dictate. 



The book, as its title implies, deals largely with the 

 Principles of Soil Technology, and applications of these 

 to local practice should constitute a part of the instruc- 

 tion. 



Attention is called to the outline of contents, which 

 shows the method of treatment and the relation of the 

 several parts of the subject. As an elementary treatise, it 

 has been the aim to properly balance the discussion of 

 all phases of the subject, which may be followed in 

 greater detail in advanced courses. 



In the illustrations, endeavor has been made to 

 include cuts of all of the more common types of soil- 

 working implements. We are indebted to the United 

 States Bureau of Soils for several illustrations, and to 

 Pfeffer's 'Pfiangenphysiology' for three cuts which, by 

 mistake, were not credited in the text. 



THE AUTHORS 



Cornell University, 



Ithaca, N. Y. 



October 18, 1909. 



