430 GK. Gilbert—The Deflection of Streams. 
tion. Where the curvature has a convexity to the right, these 
two influences conspire, and their resultant is deducible by 
addition. ' Where the curvature has a leftward convexity the 
influences are opposed, and their resultant is deducible by sub- 
traction. [The terminology here and through the remainder of 
the paper is adjusted to the northern hemisphere exclusively.]. 
If we represent by R the joint selective power on curvatures of 
right hand convexity and by L the joint selective power on 
curvatures of left hand convexity, then we deduce by simple 
combinations and transformations of equations (8) and (4). 
R _v,+2,+2pn sin : ‘ (5) 
L™~ v,+,—2n sin A 
v, and v, may be the velocities of any two threads of current. 
moving at different rates, but for purposes of convenience and 
simplification we now assume that they are symmetrically re- 
lated to the mean velocity v; and introducing this relation in 
(5) we obtain , 
Ro +pn sin r : : (6) 
L v—pnsinaA 
together with all other channel features, are determined by the 
water at its flood stage. It is therefore proper to consider 10 
this connection the mean flood velocity. That was determined 
by Humphreys and Abbott to be, at. Columbus, Kentucky, 8° 
feet per second. The latitude of the locality is 37°. Giving 
these values to p, v, A, and substituting for 7 its numerical 
value ‘000072924, we obtain from (6) 
R 
e =< 081 
ple suffices to show that while the influence of rotation is sma¥', 
as compared to that of curvature, it is still of the same ord 
