Diurnal Tides on the Coasts of Ireland. 99 



From the preceding Tables the Solar and Lunar Diurnal Tides at Do- 

 naghadee were calculated separately, and found to give the following results : — 



I. — Diurnal Tide at High Water. 



1. Maximum value of Lunar Tide for Positive Heights = 042 ft. 



2. Maximum value of Lunar Tide for Negative Heights =: 0'38 ft. 



3. Maximum value of Solar Tide = 0-28 ft. 



4. Diurnal Solitidal Interval = 11" 12°'. 



5. Age of Lunar Tide = 6" 5". 



IL — Diurnal Tide at Low Water. 



1. Maximum value of Lunar Tide for Positive Heights = 0-39 ft. 



2. Maximum value of Lunar Tide for Negative Heights — 0-42 ft. 



3. Maximum value of Solar Tide = 0-28 ft. 



4. Diurnal Solitidal Interval = 11* 12"". 



5. Age of Lunar Tide = 5" 2\ 



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



Range of Lunar Tide at High "Water = 0-80 ft. 

 Range of Lunar Tide at Low Water = 0'81 ft. 



Hence, by equation (3), 



cot(m-?„.) = ^ = cot(45°21'), 



or, converting the arc into time, 



m - 4 = 3" 7"- ; 



but since m is the Moon's Hour-angle, in Donaghadee time, at High Water, and 

 is 10" 40"", we obtain, finally, 



»„. = 7" 33'". 

 By equation (4), we have 



Max. value of 2M sin 2m = V (O-SOy+JO-81)' = 1 -1 39 ft. 



o2 



