Frictional Resistance in Artificial Waterways 27 
these sections the channel is in excellent condition, perfectly 
straight and of uniform cross-section and grade. Elevations of 
the water surface and cross-sectional area measurements were made 
at intervals throughout their lengths. The water surface pulsated 
.01 feet. 
Section (a), Fig. 9, borders on Stone Street, Pueblo, and is 
1,495 feet in length. Its bed is of smooth, waterworn adobe, from 
which project very fine rootlets from the cottonwood trees planted 
in rows on either side of the canal. 
Section (b), Fig. 10, also bordering on Stone Street, Pueblo, 
has a lining of smooth, waterworn adobe, but the absence of root¬ 
lets accounts for the low value of (n) in comparison with section 
(a). Its length is 1,600 feet. 
