Diurnal Tides on the Coasts of Ireland. 73 



Hence, by equation (3), 



cot(m-4) = ^ = cot(23°28'), 



which, converted into time, gives 



m - in, = P 37"" ; 



but m, the Moon's Hour-angle at High Water, is, in Rathmullan time, 5'' 43'"; 

 and, therefore, 



4 = 4" 6"-. 

 By equation (4), we have 



Maximum value of 23/ sin 2/i = /(0-76)^ + (0-33)' = 0-829 ft. 



From which we obtain 



l/=0-632ft. ; 



and since the maximum value of the Solar Tide is 023 ft., we have by equa- 

 tion (5), 



Max, value of 25 sin 2<t = 0-4G ft., 

 and, therefore, 



5=0-315 ft. 



Combining together the preceding results, we obtain the following Diurnal 

 Tidal Constants for Kathmullan : — 



1. Lunitidal Interval = 4* 6'". 



2. Solitidal Interval = 9" 40"". 



3. Age of Lunar Tide at High Water =5'' 10". 

 Am of Lunar Tide at Low Water = 4" 20". 



4. Lunar Coefficient = 0-632 ft. 



5. Solar Coefficient = 0-315 ft. 



6. Ratio of Solar to Lunar Coefficient, 



or 4=0-498. 

 M 



The Solar and Lunar Tides were carefully constructed from the preceding 

 Constants, and compared with the observed Tides. The results of this compa- 

 rison are given in the six following Tables: — 



VOL. XXIIl. L 



