PREFACE VII 



Teaching the applications of science to the industries 

 and the arts will give the pupils the first insight into their 

 own desires and capabilities. They will thus begin un- 

 consciously to prepare themselves along the line of pre- 

 vocational work. Later they will also realize the dignity 

 of labor, and the science teaching may easily develop into 

 the various branches of vocational work, and the pupils 

 may be given the rare opportunity of viewing the field of 

 human endeavor and of truly choosing their career in life. 



Many new texts and other publications have been 

 freely consulted in the preparation of this book. Since 

 much of the material has become common property, 

 specific acknowledgment has not been made, but the 

 author takes this opportunity of thanking the many pub- 

 lishers who have so kindly supplied him with reference 

 books. 



Especial thanks are due Mr. James B. Davidson, 

 Superintendent of Schools of Marin County, California, 

 and Mr. David R. Jones, City Superintendent of Schools 

 of San Rafael, California, both of whom have read the 

 manuscript and have given to the book the benefit of 

 their experience. Thanks are also due Messrs Boggs, 

 Davalos, and Persell who made many of the drawings. 

 Acknowledgement is made through the text for other 

 special obligations. The author alone is responsible for 

 any mistakes which may have crept into the work. 



PERCY ELLIOTT ROWELL. 

 Berkeley, California. 

 Tuly, 1913 



