viii CONTENTS 



CHAPTER VI 



MATHEMATICAL FORMULA 



PAGE 



Hawksley; Biirkli-Ziegler; Adams, McMath; Analysis of Factors Com- 

 pared with those of N. Y. Diagrams; New Orleans Diagram; Crane's 

 Slide-rule; Dow's Diagram 78 



CHAPTER VII 



ESTIMATING FUTURE POPULATION 



Census Reports; Chicago and Baltimore Curves; Comparison of Different 

 Cities; Boston and Brockton Methods; Laws of Rafter-Baker; Kuich- 

 ling's Law; Future Population of Ithaca 93 



CHAPTER VIII 



AMOUNT OF SEWAGE PER CAPITA 



Relation between Amount of Sewage and Water-supply; Consumption in 

 American Cities; Analysis for Boston's Future Supply; Analysis at New- 

 ton, Mass.; Examples of Variation of Water-consumption and of Sewage- 

 flow in American Cities; Methods of Stating the Amount of Maximum 

 flow 105 



CHAPTER IX 



GROUND-WATER REACHING SEWERS 



Variation in Height of Ground-water; Statistics of Amount of Infiltration; 

 Coffin's Experiments on Tightness of Pipe-joints; Senior's Experiments; 

 Conclusions 142 



CHAPTER X 



GRADES AND SELF-CLEANSING VELOCITIES 



Hooker's Thesis on Suspension of Solids in Flowing Water; Relation by 

 Experiment between Velocity and Suspension; Effect of Shape and 

 Specific Gravity of Pieces Moved; Velocities Required by Engineers; 

 Grades Required to Secure these Velocities 153 



CHAPTER XI 



DEVELOPMENT OF FORMULA. FOR FLOW 



Chezy formula; de Prony's Formula; Eytelwein's Formula; Weisbach'a 

 Coefficients; Latham's Tables; Darcy's Experiments; Bazin's Formula; 

 Humphreys & Abbot; English Formulae 165 



