EXPLANATION OF BOOK NUMBERING 



THE numbers, as given in the list which follows, may be 

 written on Dennison's Labels No. 539, and affixed to the back 

 of the binding, below the title of the respective books. This 

 must be in addition to any other system of numbering, and it 

 may be well to number the books also on the inside of the front 

 cover, in order to save time in case the outside labels come 

 off. 



It would be advisable to segregate the books to be used 

 with this outline, and to arrange them according to the num- 

 bering. This plan permits the pupils to work rapidly and 

 effectively, since they may obtain a desired book, directly by 

 number, without hunting for title or author. Wherever this 

 system has been established, success has marked it from the 

 start. The starred books are those which are referred to by 

 number, and are the most important in connection with this 

 outline. 



The publications of the United States Department of Ag- 

 riculture may be obtained, free of charge, by addressing the 

 Secretary of Agriculture, Washington, D. C. A catalogue of 

 the publications of this department will serve as a source of 

 valuable information, and it should be in the hands of every 

 science teacher. It may be obtained free upon application. 

 The teacher should have the school listed to receive the 

 " Monthly List of Publications," which is sent free upon re- 

 quest. 



xxi 



