434 A. C. Baines—The Deflection of Streams 
Art. LIT.—On the Sufficiency of Terrestrial Rotation for the 
Deflection of Streams ; by A. C. BAINEs. 
In a paper on this subject in the June number of this 
Journal Mr. G. K. Gilbert has investigated the combined effect 
of the earth’s rotation and the centrifugal force in causing a 
difference in the velocity at the right and the left banks of 
rivers, and has shown that where a river flows in a curve the 
line of maximum velocity is shifted toward the right bank by 
the combined action of the deflecting force due to the earth’s 
rotation and the centrifugal force developed in moving along a 
curve. Mr. Gilbert comes to the conclusion that the earth’s 
rotation is effective in causing the erosion of the right bank, 
only in connection with and as an adjunct to the centrifugal 
force—or that the earth’s rotation has no effect in shifting the 
courses of straight streams. 
No other conclusion seems possible when only the extremely 
small difference in the velocity at the right and left banks due 
to the earth’s rotation is taken into account for the small excess 
Let v be the velocity of any particle in the stream; let v, be 
the velocity of any particle at the surface; let v, be the velocity 
