vi PREFACE TO SECOND EDITION 



somewhat the earlier statements about the necessary amount 

 of leakage to be considered. 



The problems that have been added have been found very 

 useful in affording an insight into some of the broader questions 

 that enter into the design of sewers, as well as in giving the stu- 

 dent a chance to apply his theory to a concrete example. 



The book as a whole is not materially changed, and continued 

 experience in large classes has confirmed the author in his belief 

 that for the general course student in Civil Engineering it con- 

 tains the essentials of sewer design so arranged as to be readily 

 intelligible to the average mind. 



H. N. 0. 



