68 



BULLETIN 376, U. S. DEPARTMENT OF AGRICULTURE. 



Rela+ive capacities -for left slants >jI- ^i~ 



Relative capacities tor right slants. 



Fig. 6. — Logaritlunic diagram showing relative capacities of wood-stave pipe of various diameters for 

 any given liydraulic gradient. For instance, an 8-inch pipe will carry one-third as much as a 12-inch 

 pipe, and an 18-inch pipe will carry three times as much as a 12-inch pipe. For the first problem, enter 

 the diagram at the bottom (as noted) on the left slanting line leading from 12 inches as a base. The inter* 

 section of this slant with the vertical line above 8 is approximately on the horizontal line representing 1/3, 

 as shown by figures at left of diagram. Similarly for the second problem follow the right slant from 12 

 as a base to the intersection of this slant with the vertical line from 18. This intersection is approxi- 

 mately on the horizontal line representing 3 as shown by figures at right of diagram. 



