PREFACE IX 



the other comprises seventy-six books, so chosen as to enable 

 the instructor to emphasize any particular branch of science. 

 It is not intended that all of the references be utilized. The 

 General Science course should be adapted to the locality. It 

 is easier for the teacher to select what is wanted, from a suffi- 

 ciently large list, than it is to hunt for material outside of the 

 references. 



In addition to these library books, the list of the publica- 

 tions of the United States Department of Agriculture is quite 

 large and the number of references to them considerable. 

 New publications are constantly appearing, and the teacher 

 may add to this list indefinitely. The pupils should be urged 

 to get the " bulletin habit." 



I wish to thank the publishers of the books to which I have 

 referred for their kindness and cooperation, and the teachers 

 who have supplied me with valuable suggestions. Especially 

 do I wish to express my appreciation to Mr. Allan B. Camp- 

 bell for his assistance, without which the appearance of the 

 book this year would have been impossible. To one other, 

 however, the greatest credit is due, for her assistance ex- 

 tends back through many patient years, and without her 

 stimulating influence the ability to gather together the facts 

 contained in this outline would have been an impossibility at 

 any time. To her this book is dedicated. 



PERCY ELLIOTT ROWELL. 



Los ANGELES, CALIFORNIA, 

 July, 1911. 



