PREFACE 



THIS book is not intended to prepare for college entrance 

 examinations ; it will not, in fact, prepare for any of the 

 present-day stock examinations in physics, chemistry, or 

 hygiene, but it should prepare the thoughtful reader to meet 

 wisely and actively some of life's important problems, and 

 should enable him to pass muster on the principles and 

 theories underlying scientific, and therefore economic, man- 

 agement, whether in the shop or in the home. 



We hear a great deal about the conservation of our natural 

 resources, such as forests and waterways ; it is hoped that 

 this book will show the vital importance of the conservation 

 of human strength and health, and the irreparable loss to 

 society of energy uselessly dissipated, either in idle worry 

 or in aimless activity. Most of us would reproach ourselves 

 for lack of shrewdness if we spent for any article more than 

 it was worth, yet few of us consider that we daily expend 

 on domestic and business tasks an amount of energy far in 

 excess of that actually required. The farmer who flails his 

 grain instead of threshing it wastes time and energy ; the 

 housewife who washes with her hands alone and does not 

 aid herself by the use of washing machine and proper bleach- 

 ing agents dissipates energy sadly needed for other duties. 



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