Diurnal Tides on the Coasts of Ireland. 129 



. 0-33 deduced from Heights. 



. 0-34 do. do. 



. 03.5 deduced from Times. 



. 0-38 do. do. 



0-35 



According to the Statical Theory of the Tides, the ratio of the Solar to the 

 Lunar effect should be the same for the Diurnal and for the Semidiurnal Tides ; 

 but according to the Dynamical Theories of the Tides, the coefficients in the 

 Solar and Lunar Tides depend in a different manner on the depth of the sea, and 

 therefore, the ratios deduced from the Diurnal and Semidiurnal Tides should be 

 different. According to the Statical Theory of the Tides, excluding the terms 

 depending on Parallax, DecHnation, Hour of Tide, &c., the ratio of the Solar to 

 the Lunar Coefficient is as follows : — 



Solar Coefficient »S (/' .„, 



Lunar Coefficient ^Tl^U'' ^ ^ 



In this equation S and M denote the masses of the Sun and Moon, and Z>, d 

 their mean distances from the Earth. Adopting the received values of these 

 quantities, we should have 



■^ = 359551 X 85; 

 M 



d 59-964 



D 2 X 12032' 



and substituting these values in equation (6), we find, 



Solar Coefficient 



Lunar Coefficient 



= 0-47288. (7) 



S 

 If, instead of calculating the right-hand side of (6), we consider ^ as the 



unknown quantity, and introduce the values of the left-hand side deduced from 



the Tides, we obtain the two following values of the ratio of the Sun's mass to 

 the Moon's, from the Semidiurnal and Diurnal Tides respectively, 



VOL. XXIU. S 



