Diurnal Tides of the Coasts of Ireland. 269 



Adding together the first two of each of the preceding, we 



Range of lunar tide at high water =0-43 ft. 

 Range of lunar tide at low water =0-37 ft. 



Hence by equation (3), 



cot(m-z,„)=^ = cot(40°43'); 



or, converting the arc into time, 



m-4=2J»48"»; 



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

 Dunmore time, is 4^ SG"", we obtain 



4=1^48'". 

 By equation (4), we have 



max. value of 2M sin 2/.= ^(0-43)^+ (0-37r=0-567 ft. ; 



from which we obtain 



M= 0-441 ft. 



Also, since the mean value of the solar tide is 0-14 feet, we have 

 by equation (5), 



max. value of 2S sin 2o-=0-28 ft., 



S= 0-192 ft. 



Combining the foregoing results, we obtain for the tide con- 

 stants at Dunmore, — 



1. Lunitidal interval =1^48'». 



2. Solitidal intei-val =5^ 'i5"'. 



3. Age of lunar tide 



athigh water =5*1 19'». 

 at low water =5^ 14^^. 



4. Lunar coefficient =0-441 ft. 



5. Solar coefficient =0-192 ft. 



6. Ratio of solar to lunar coefficient, 



or If =0-436. 

 M 



The theoretical tides were constructed with the foregoing tide 

 constants, and compared with the observed tides, with the follow- 

 ing results. 



