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LI I. On the Tides on the Coast of Great Britain. By 

 J. W. LUBBOCK, Esq. F.R.S* 



[With a Map.] 



1X/TUCH valuable information on the subject of the tides 

 *-*-* being scattered in works relating to navigation, it may 

 perhaps be useful to exhibit at one view in a small map the 

 progress of the tide or high water round Great Britain, where 

 it is better known than in any other part of the globe, the rise 

 throughout being considerable, and therefore the time of high 

 water easily observed. The plan of the map is taken from 

 one in the first volume of Dr. Young's Lectures on Natural 

 Philosophy. I hope it may tend to draw the attention of sci- 

 entific men residing on the coast to this important subject, 

 which has been hitherto so much neglected. It is to be re- 

 gretted that the time of high water is not given in all maps 

 in those few places where it is known with sufficient ac- 

 curacy. 



The progress of the tide round Great Britain is a striking 

 instance how much this phenomenon is influenced by local 

 circumstances : for while the tide in the open ocean follows the 

 moon, proceeding from East to West; here the general direc- 

 tion, and particularly that of the tide up the Channel, is from 

 West to East. The tide which arrives from the Atlantic divides 

 into two branches ; the one going up St. George's Channel, 

 the other up the English Channel. The former meets the tide 

 from the north-west coast of Ireland near St. John's Point 

 on the north-east coast of Ireland, opposite the Isle of Man. 

 The other branch proceeds up the Channel, making high water 

 at Beachy Head, Dungeness, and Deal, at nearly the same 

 time as at Dieppe, Boulogne and Calais. This tide appears to 

 divide, after passing the Straits of Dover, into two branches ; 

 one of which meets the tide which comes from the North, at 

 the sand called the Kentish Knock ; the other branch makes 

 flood tide along the opposite coasts of Flanders, Holland 

 and Jutland, as far as the entrance of the Sleeve. The tide 

 from the north-west coast of Ireland divides into two branches; 

 one of which meets the tide which comes up St. George's Chan- 

 nel near St. John's Point, as before said ; the other proceeds 

 round the coast of Great Britain until it meets the tide which 

 comes up the English Channel, off' the Kentish Knock. 



There is no perceptible tide on the opposite coast of Nor- 

 way, although there is further north, as at Hammerfest and 

 at the North Cape. The crest of the tide which makes high 



* Communicated by the Author. 



water 



