PREFACE V 



revision of the chapters on General Chemistry and the 

 critical reading of the whole text, and to Dr. C. A. Peters, 

 Amherst Agricultural College, for many helpful sugges- 

 tions and criticisms. Acknowledgment is made to Mr. J. 

 Ross Hanahan of Planters' Fertilizer Company for Figs. 

 37, 38 and 39, to Mr. John S. Carroll of the German Kali 

 Company for Figs. 40, 41 and 42 and 52-60, and to Dr. 

 Wm. S. Myers of the Chilean Nitrate Propaganda for Figs. 

 45-51. The following members of the faculty of Clemson 

 College furnished photographs: Director J. N. Harper, Dr. 

 F. H. H. Calhoun, Prof. W. A. Thomas, and Mr. F. G. 

 Tarbox. Mr. T. C. Hough furnished valuable aid by mak- 

 ing drawings. Director Thorne of the Ohio Experiment 

 Station and Director Hartwell of the Rhode Island Experi- 

 ment Station very kindly gave permission for the repro- 

 duction of cuts used to illustrate bulletins of their respective 

 stations. Cuts from Farmers' Bulletins of the United States 

 Department of Agriculture were reproduced as well as cuts 

 from bulletins of the South Carolina Experiment Station. 



Standard books that bear on the subject have been 

 freely consulted. Grateful acknowledgment is also due 

 my father, Thomas W. Keitt, for valuable assistance in 

 reading proof. 



T. E. KEITT. 



CLEMSON COLLEGE, 1916. 



