xii PREFACE 



list of books on irrigation. No attempt is made to supply 

 in this volume a complete bibliography of irrigation. 



To friends and colleagues in many parts of the world 

 hearty thanks are offered for valuable help rendered in 

 the preparation of this book. My Utah colleagues, many 

 of whom have been connected with the long experimental 

 study of irrigation at the Utah Station, have given freely 

 of their time and information to make the book accurate 

 and worthy of the cause. I am under particular obliga- 

 tion to Dr. Robert Stewart, Dr. F. S. Harris, Prof. W. W. 

 McLaughlin and Prof. L. A. Merrill, and to Librarian 

 Elizabeth C. Smith, who has kindly gathered irrigation 

 literature from all parts of the world. My brother, Prof. 

 O. J. P. Widtsoe, has in many ways given most valuable 

 help. If this book and its companion volume shall be of 

 service, the first credit belongs to Dr. L. H. Bailey, the 

 Editor of the Rural Series of books, through whose wise 

 and kindly urging these books were written, and the many 

 others, by other hands, which have made available to 

 humanity the great applications of modern science to 

 rural problems. 



JOHN A. WIDTSOE. 



LOGAN, UTAH. 



NOTE. Unless otherwise stated, wherever 

 "inch" or "foot" of water is used in this book 

 it refers to the depth to which the water would 

 cover the ground. 



