118 



THE OCEAN. 



the ebb and flow, restrained between clialns of rocks and shallows, 

 move at the time of high water with a speed of nearly 10 miles per 

 hour. Then comes the strait which bears the significant name of 

 the Deroute Passage, and in which the currents flowing along the 



Fig. 41.— Course of the Tide in the Irish Sea. 



rugged western coast of Cotentin meet those which come directly 

 from the open sea by the breach opened between the islands of 

 Jersey and Guernsey ; there the marine rivers, less rapid, are never- 

 theless animated by a speed of nearly 10 feet per second.* Since the 

 disaster of La Hogue, where Tourville, unable to sail against the for- 

 * Mounier, Memoire sur Us Courants de la Manche. 



