Diui-nal Tides of the Coasts of Ireland. 119 



I. Diurnal tide at high water. 



1. Maximum value of lunar tide for positive heights =0*50 ft. 



2. iMaximum value of lunar tide for negative heights =0"33 ft. 



3. Maximum value of solar tide =0-30 ft. 



4. Diurnal solitidal interval =11'^ 25"". 



5. Age of lunar tide =6d 181^ 41"». 



II. Diurnal tide at low water. 



1 . Maximum value of lunar tide for positive heights = 0'355 ft. 



2. Maximum value of lunar tide for negative heights = 0*45 ft. 



3. Maximum value of solar tide =0*25 ft. 



4. Diurnal solitidal interval =11^ 25"^. 



5. Age of lunar tide =5'i 2^^ 45'a. 



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

 Range of lunar tide at high water =0*83 ft. 

 Range of lunar tide at low water =0-805 ft. 

 Hence by equation (3), 



cot (m-ij = q:^^ = cot (44° 7') ; 



or, converting the arc into time, 



m—^r,^ = ^^ 2"»; 

 but since m, the moon's hour-angle at high water expressed in 

 Cushendall time, is 10*^ 18°^, we obtain 



u=7ii le-^. 



By equation (4), we have 



max. value of 2M sin2/i= >/ (0-83)2 + (0-805)2 = l-156 ft; 

 from which we obtain 



M = 0-881 ft. 



Also, since the mean value of the solar tide is 0*275 feet, we have 



max. value of 2S sin 2cr = 0-550 ft., 

 and 



S= 0-376 ft. 



Combining the foregoing results, we find for the tide constants 

 at Cushendall, — 



1. Lunitidal interval =7'^ 16™. 



2. Solitidal interval =ll'^25n». 



3. Age of lunar tide 



at high water =6'i \^^ 41«'. 

 at low water =5'^ 2^ 45"*. 



4. Lunar coefficient =0-881 ft. 



5. Solar coefficient =0-376 ft. 



6. Ratio of solar to lunar coefficient, 



or 4 =0-427. 

 M 



