EUSII OF THE TIDE UP EIVEIIS. 121 



they arrived at the sea-shore Ganga recoiled with aifiight before the 

 impure and monstrous ocean; she fled abruptly by a 'thousand channels, 

 and since that epoch she comes and goes by turns, now venturing to 

 descend, and now fleeing again towards the mountains, twice a day.* 

 It is in the bay of the Seine that the mascaret, or " eager," has been 

 most regularly and carefully observed. Flowing from the open sea 

 with a speed of from 15 to 20 feet per second, the liquid wall 

 remains curved towards the centre, under the pressure of the fluvial 

 current. The two points of the enormous crescent break in foam on 

 the shores ; while in the middle of the concavity, the even, rounded 

 wave advances without even rippling the water before it. It seems 

 to turn on the river like a gigantic serpent ; rising from 6 J to 10 

 feet above the liquid plain ; whilst behind it rise waves or eteules in 

 concentric undulations quite as high, the advanced guard of the 

 tidal mass. All the obstacles placed in the way of the mascaret 



Fig. 42.— Profile of a tidal wave observed in the bay of the Seine (after M. Partiot). 



irritate it by increasing its impetus ; at length the tide, entering a 



left bank 



Fig. 43.— Height of the "mascaret" or tidal wave observed between Caudebec and Meilleraye 

 (after M. Partiot). 



wider and deeper part of the bed, gradually calms and moderates its 

 height till it meets with another shallow or promontory. Moreover, 

 each tide- wave is distinguished from the preceding by reason of the 

 difference of winds, currents, and the masses of water put in motion. 

 There is nothing more curious than to see, from the height of a pro- 

 montory, two waves repelled obliquely by the banks crossing their 

 furrows, and their eteules. 



The sole means of diminishing the force of the mascaret, which in 

 several estuaries, and especially in the bay of the Seine, is some- 

 times dangerous to small vessels, is to regulate the channel by deep- 

 ening the shallows and straightening the banks. The works, 

 * Carl Ritter ; Von Hoff, Verdnderungen der Erdoberfldche, t. i. p. 378. 



