Diurnal Tides of the Coasts of Ireland. 263 



Adding the first two of each of the preceding, we find — 



Range of lunar tide at high water =0'625 ft. 

 Range of lunar tide at low water =0"670 ft. 



Hence by equation (3), 



cot {m-i„,) = ^7^ = cot (47°) j 



or, convei'tiug the arc into time, 



TO — i„j = 3^ 14'»; 



but since m is the moon's hour-angle in Kingstown time, at 

 high water, and is equal to lO'* 53™, we find 



i„,=7^39'^. 

 By equation (4), we have 



max. value of 2Msin2^= -/ (0-625)2 + (0-670)2 = 0-916 f^ . 



from which we obtain 



M = 0-685 ft. 



Also, since the maximum value of the solar tide is 0-255 ft., we 

 find 



max. value of 2S sin 2o-=0-510 ft., 

 and 



S = 0-348 ft. 



Combining these results, we obtain as tide constants at Kings- 

 town, — 



1 . Lunitidal interval = 7^ SQ"*. 



2. Solitidal interval = 10»» 26°». 



3. Age of lunar tide 



at high water =6^ 17''. 

 at low water =4^^ II**. 



4. Lunar coefficient =0-685 ft. 



5. Solar coefficient =0-348 ft. 



6. Ratio of solar to lunar coefficient, 



or 4 =0-508. 

 M 



The theoretical tides were carefully constructed with the 

 foregoing constants, and compared with the observed tides. 

 The results of the comparison arc contained in the following 

 Tables:— 



