TIDAL WAVES. 113 



by the intervention of the British islands, and the 

 comparatively narrow space between England and 

 France, is very remarkable on the Danish shores, 

 where the ebb and flow of the sea ceases to be 

 perceptible, and it is constantly high water. 



The height to which the tide flows is various 

 in different parts of the world, and this dissimi- 

 larity is chiefly occasioned by the conformation 

 of the coast. In the Mediterranean there is 

 little or no tide, while in some parts of the 

 American coast, as in the Bay of Fundy, the 

 spring tide frequently rises to the extraordinary 

 height of 120 feet, and in Asia, as at the mouth 

 of the Indus, the rise of the tide is 30 feet. 

 Even in Britain there is great difference in the 

 depth of high water at different places. At Chep- 

 stow, in the Bristol Channel, the rise of the tide 

 is much higher than in many other places, being 

 from 45 to 60 feet, and, after a strong westerly 

 wind, it is said sometimes to reach 70 feet. 



The very striking phenomenon called the Bore 

 cannot be passed over in silence while referring to 

 the subject of the tides. Where an estuary is 

 narrow, and the shore is level to a considerable 

 distance inland, the great body of water pro- 

 duced by the tidal wave being suddenly forced 

 into a confined space, rises to a proportionate 

 height between the opposite shores, and flows 

 onward, partly under the influence of the original 

 impulse acting upon it, and partly by its own 

 gravitation 1 ! Into the Bay of Fundy, already men- 

 tioned, the (i bore " rushes with tremendous force, 

 I 



