Familiar letters of the physics of the Earth : treating of the chief movements of the land, the waters, and the air, and the forces that give rise to them /
Henry Buff, A. W. Hofmann · 1851
FLOW OF RIVERS.Ly.the whole of the water touches the bottom, in its turn, in a shorter time, and thus meets with more | stoppage.This cannot happen so much with deep water, because the film that touches the bottom is much smaller in proportion to the bulk of water that is above it.This shows why the water taken across the breadth ofa stream, at any given place, runs more slowly in the shallow parts than in the deeper; and why again the rate of flow of brooks and rivers is greater when they are swelled by floods.And now you will see why, when, in very winding rivers, suitable cuttmgs are made, which shorten the channel, and for equal lengths increase the fall, the level of the water above must be lowered.The same cause, too, which in every case favours 18 THE TIDES; and slower, till, after three hours more, the flood-.ee ee rll erm -. a CN a e e hi