136 The Rev. Samuel Hadghton on the Solar and Lunar 



a cos A _a 



6cosJ5~^' C12) 



a cos A a 



e cos C~ y' 



aud, since the angle between Bunown and Dunmore is 84°, and between Bunown 



and Portrush is 32°, we have also, 



A-c = sr. ^^^^ 



The following values of a, b, c, are found by measurement ; and of a, /3, 7, from 

 the Table of Establishments, 



a= 444, a= 25'", 

 b= 590, li= 90"', 

 c = 1207, 7=203". 



Introducing these values into equations (12) and (13). we obtain from the first 



equation, 



^ = 69° 6' ; 



and from the second equation, 



A = 76° 6'. 



The mean of these two values is 72° 36', and since the line joining Caherciveen 

 and Bunown is a meridian (nearly), it follows that the Lunar Diurnal Cotidal 

 line, on the west coast of Ireland, is 17° 24' west of north ; and that the 

 Tide approaches the coast from the W. 17° 24' S. 



The Solar Diiu-nal Tide approaches the coast in a different direction, as is 

 seen from the fact that it arrives at Bunown before it reaches Caherciveen ; 

 and it also appears to undergo some unexplained retardation in the narrow 

 channel between Antrim and Scotland, as it arrives at Cushendall and Portrush 

 later than at any other stations. 



3. — Age of Lunar Diurnal Tide. 



The following Table gives the Age of the Lunar Diurnal Tide at each of 

 the Irish stations :— 



