sometimes by a fourth. These watery mountains spread across the whole channel, and advance with a prodigious rapidity, rending and crushing everything in their way. Immense trees are sometimes uprooted by it and sometimes whole tracts of land are swept away.
Tidal Currents in Rivers
There is no appreciable tidal effect in rivers due directly to the tidal attraction of the sun and moon, but the tidal wave in a river is
- See G. H. Darwin, "The Tides," etc., Scribners, 1898. This contains also an account of the Hangchow Bore based on Captain Moore's survey, to which we shall refer later on.