1Q2 
SCENERY OF SWITZERLAND. 
inclined plane in a more or less straight line, any in- 
equality or obstruction, or the entrance of a side 
stream, would drive the water to one side, and when 
once diverted it would continue in the new direction, 
until the force of gravity drawing the water in a 
straight line downwards equalled that of the force 
tending to divert its course. Hence the radius of 
the curves will follow a regular curve-law depending 
on the volume of water and the angle of inclination 
C 
W 
JR 
Fig. 48.— Diagrammatic Section of a Valley (exaggerated) . R R, Rocky 
basis of valley; A A, Sedimentary strata; B, Ordinary level of river- 
C, Flood level. 
of the bed. If the fall is ten feet per mile and the 
soil homogenous, the curves would be so much ex- 
tended that the course would appear almost straight. 
With a fall of 1 foot per mile the length of the curve 
is, according to Fergusson, about six times the width 
of the river, so that a river 1000 feet wide would 
oscillate once in 6000 feet. This is an important 
consideration and much labour has been lost in trying 
to prevent rivers from following their natural laws of 
oscillation. But rivers are very true to their own 
