5G0 



TIDAL WAVE CALLED 'THE BORE.' 



[Cu. XXI. 



away a quarter of a mile of land in three years ending in 



1786* 



Tidal wave called ' the Bore.' — Before concluding my re- 

 marks on the action of the tides, I must not omit to men- 

 tion the wave called 'the Bore,' which is sometimes pro- 

 duced in a river where a large body of water is made to rise 

 suddenly, in consequence of the contraction of the channel. 

 This wave terminates abruptly on the inland side ; because 

 the quantity of water contained in it is so great, and its 

 motion so rapid, that time is not allowed for the surface of 

 the river to be immediately raised by means of transmitted 

 pressure. A tide wave thus rendered abrupt has a close 

 rmnWv. observes Mr. Whewell, to the waves which curl over 



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The Bore which enters the Severn, where the phenomenon 

 is of almost daily occurrence, is sometimes nine feet high, 

 and at spring-tides rushes up the estuary with extraordinary 

 rapidity. The finest example which I have seen of this wave 



ISTova 



said to rise in some 



places seventy feet perpendicular, and to be the highest in 

 the world. In the large estuary of the Shubenacadie, which 

 connects with another estuary called the Basin of Mines, 

 itself an embranchment of the Bay of Fundy, a vast body of 

 water comes rushing up, with a roaring noise, into a long 

 narrow channel, and Avhile it is ascending, has all the ap- 

 pearance of pouring down a slope as steep as that of the 

 celebrated rapids of the St. Lawrence. In picturesque 

 effect, however, it bears no comparison, for instead of the 

 transparent green water and snow-white foam of the St. 

 Lawrence, the whole current of the Shubenacadie is turbid 

 and densely charged with red mud. The same phenomenon 

 is frequently witnessed in the principal branches of the 



Me 



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In 



HoojzIv.' savs Eennell, ' the Bore commences at H 



Point, the place where the river first contracts itself, and is 



H 



|V 



is its motion, 



Von Hoff, vol. i. p. CO. 

 t Phil. Trans. 1833, p. 204. 

 I See Lyell's Travels in North Ame- 



ri1*r, in 1842, vol. ii. p. 166. London, 



1845. 



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