PREFACE 



The experiments described on the following pages 

 are designed especially for the use of the students in 

 the four-year course in agriculture in colleges and 

 universities. 



These exercises will give sufficient work to cover 

 two or three terms, depending upon the number of 

 hours devoted to laboratory practice each week. An 

 effort has been made to outline the experiments as 

 clearly and concisely as possible, in order that the 

 student may take up each exercise without delay. 



While these practices are the outcome of several 

 years' experience in teaching Soil Physics at the 

 Ohio State University, they are not all original with 

 the author. Material has been drawn from various 

 sources, and so arranged that it may be adapted to 

 instruction in soils under a wide range of conditions. 



Acknowledgment is due my assistant, Mr. G. R. 

 Hyslop, for valuable suggestions and aid in working 

 out these practices, and to the following for material 

 and suggestions. Prof. M. F. IMiller, University of 

 Missouri, Prof. E. O. Pippin, Cornell University, Dr. 

 L. J. Briggs, U. S. Dept. of Agriculture, Professors 

 Stevenson and Schaub of Iowa State College, and 

 others. 



A. G. McCall. 



Soil Physics Laboratory 



Ohio State University 



Columbus, Ohio. 



August, 1908, ivil999e6 



