vi SUGGESTIONS TO TEACHERS 



A supply of clean sand, and also some loam, clay and 

 muck soil should be secured in the fall. This material should 

 be dried, pulverized, and passed through a sieve with one- 

 eighth-inch mesh, to remove stones and sticks. 



The exercises are intended to furnish sufficient material 

 for one period per week throughout the year or two periods 

 per week for a half year. Although they are arranged in 

 logical order, it is not necessary that the exercises should 

 be taken up in the exact sequence in which they occur 

 in the text. Indeed, it will be necessary for the teacher 

 to vary the arrangement in order to adapt the study to 

 the season and to the facilities of the school. 



A small working library should form a part of the 

 equipment. For a study of soils this library should include 

 several elementary books on soils, a collection of Farmers' 

 Bulletins from the United States Department of Agriculture 

 and the publications of the State Experiment Station. 



While much of the material in the text is original, the 

 writer has drawn freely from all sources for suggestions 

 and illustrative material. Some of the illustrations have 

 been adapted from the text-books and much material has 

 been taken from the publications of the Agricultural 

 Extension Department. The author wishes to make espe- 

 cial acknowledgment of the helpful suggestions of former 

 Superintendent A. B. Graham and Mr. Clark S. Wheeler 

 of the Agricultural Extension Department of the Ohio 



State University. 



A. G. McCall. 



Department of Agronomy, 

 Ohio State University, 

 June, 1915. 



