186 



SEWER DESIGN 



are made ten times the true value. The diagram is supple- 

 mented by Mr. F. S. Bailey, in order to show larger sizes and 

 is published in enlarged form in Engineering News, Vol. XXXII, 

 p. 403, the construction being as before except that the value 

 of n is taken at .015. 



A rather complicated set of formulae has been published by 

 Messrs. Adams and Gemmell (see Engineering News, Vol. 

 XXIX, p. 396) for sewers from 6 inches up to 5 feet in diameter. 

 All the values are kept in ofte diagram by placing one part 

 of the diagram to a certain scale over another part already 

 drawn to a larger scale, and by reading ordinates for one part of 

 the diagram on one side and for another to a different scale 

 on the other. The result is a very compact diagram, but one 

 likely to lead to confusion. These are the diagrams given 

 in the very convenient " Sewerage Engineer's Note-Book " 

 by Albert Wollheim, London, who thinks them the " most 

 handy diagrams yet printed." 



In the Paving and Municipal Engineer, Vol. VII, pp. 116 

 and 119, are two diagrams by John W. Hill. 



In order to make more definite the errors involved by 

 using the tables of Latham or diagrams based on those tables, 

 values of v, for various slopes and sizes of pipes have been 

 computed and are shown, side by side, in Table XXIII. 



TABLE XXV 



SHOWING VALUES OF v, FOR DIFFERENT SLOPES AND SIZES OF 

 PIPE BY FORMULA OF WEISBACH AND KUTTER 



