GENERAL MEETING. 21 
249TH MEETING. Marcu 15, 1884, 
The President in the Chair. 
Fifty members present. 
The Chair announced the election to membership of Messrs. 
Mark BrickKELL Kerr, SAMUEL Hays KAUFMANN, JOSEPH 
Sizas DILLER, CHARLES Henry WuHits, and WILLIAM Lavw- 
RENCE. P 
Mr. G. K. Gitpert made a communication on 
THE DIVERSION OF WATER COURSES BY THE ROTATION OF THE 
EARTH. 
[Abstract. ] 
It being admitted that the rivers of the northern hemisphere are, 
by the rotation of the earth, pressed against their right banks, and 
those of the southern hemisphere: against their left banks, it re- 
mains to determine whether this pressure is quantitatively sufficient 
to appreciably modify the courses of rivers. Opinion is divided, 
and the results of observation have been largely negative. Those 
who regard the cause as insufficient to produce observable results 
have approached the subject from two points of view, which are 
illustrated by the discussions of Messrs. Bertrand and Buff. The 
former computes that a river flowing in N. lat. 45° with a velocity 
of three metres per second exerts a pressure on its right bank of 
s3ss0 Of its weight, and regards this pressure as too small for con- 
sideration. The latter points out that the deflecting force, by com- 
bining with gravitation, gives the stream’s surface a slight inclina- 
tion toward the left bank, thereby increasing the depth of water 
near the right bank, and consequently increasing the velocity of 
the current at the right. This increment of velocity has a certain 
erosive effect, but it is regarded as less than that assignable to wind 
waves on the same water surface, so that the prevailing winds have 
a more important influence than the rotation of the earth. 
The object of the paper is to consider the theoretical effect from 
anew point of view. The form of cross-section of a stream flow- 
ing in a straight channel depends on the loading and unloading of 
detritus, anti is essentially stable, its character being naturally 
