Chap. T.] niENOMEXA OF THE TIDES. 117 



points round the coast, and the discrepant hours at 

 which the former occurs on the east and west coasts 

 respectively. The difFicuhies which arose in my own 

 mind on the subject, and the doubts I entertained as to 

 the accuracy of the ordinary authorities, have been so 

 satisfactorily removed by a communication from Ad- 

 miral Fitzroy, tliat I regret my inability to incorporate 

 at length the valuable information with which he has 

 supphed me. 



His opinion is, that Ceylon as a prolongation of the 

 great Indian peninsula, projects so far into the Indian 

 Ocean as to oppose an effectual barrier to the fi'ee and 

 simultaneous action of its waters, under the attraction of 

 the moon. Hence they may be considered as broken 

 into two independent sections or zones, each with a time 

 pecuhar to itself, and a tide-wave moving from east to 

 west ; — and each more or less influenced by superadded 

 phenomena, differing essentially according to the local 

 features of the respective shores. Thus the most easterly 

 tide impinges on the coast of Ceylon, reacliing Batticaloa 

 about fom^ o'clock in the afternoon, Trincomalie about 

 two hours later, and thence passing towards Coromandel 

 and Madras. Whilst this wave is pm^suing its course, 

 the moon has been already acting on the opposite 

 side of India, and forming another tide-wave akeady 

 in motion towards the coast of Arabia and Africa ; con- 

 sequently withdrawing the waters, and depressing their 

 level in the Gulf of Manaar. But before they can be 

 much reduced on the west they are overtaken by the 

 wave from the east, which arrests theu' further fall, and 

 hmits the change of level to something less than thirty 

 inches. 



Again on the moon ceasing to influence the western 

 section of the sea, the tendency of the tide-wave when 

 released from her attraction is to return towards, and 

 (because of acquired momentum) even heyofid^ its former 

 position of equilibrium, while receding towards the coast 

 of Malabar and Ceylon. Hence a continuance of oscilla- 



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