PAEAGBAPHS FOE THE TEACHEE xi 



Acknowledgements. To hundreds of young people in 



many places the author is under the profoundest 

 obligations, for they have instructed him in the point 

 of view. Specific aid has been given by many person-. 

 From the teacher's point of view, proofs have been 

 lead by Miss Julia E. Rogers, Minburn, Iowa; Miss 

 L. B. Sage, Norwich, N. Y. ; Mrs. Mary Rogers Miller, 

 lecturer of the Bureau of Nature -Study in Cornell 

 University. From the botanist's point of view, all the 

 proofs have been read by Dr. Erwin F. Smith, of 

 the Division of Vegetable Phvsiologv and Pathology, 

 United States Department of Agriculture, and his 

 suggestions have been invaluable. Chapters XI and 

 XII are adapted from two papers which were con- 

 tributed to a Farmer's Reading -Course under the 

 author's charge, by Dr. B. M. Duggar, of Cornell 

 University. Two specialists, with whom it lias been 

 the author's privilege to associate as teacher and 

 collaborator, have contributed particular parts: Dr. 

 K. ('. Davis, the greater portion of Pari III. and 

 II. Easselbring, the most of Chapter XXV. On special 

 problem- the author has had the advice of Dr. K. M. 



Wiegand, of Cornell University. 



L. II. BAILEY. 



Eorth i i.i i i; m. Department, 



< '"i.si i.i. I M\ ER8H \ . I i BACA, N. Y. 

 ( (ctober 1 . 1900. 



