272 THE ARGUMENT FOR SOLIDITY. 



periodic motion of the waters, due to the action of the moon 

 npon the oceans of a solid attracting globe, these tides, or at 

 least their average amounts, should obviously satisfy the 

 following conditions : — 



(1) The tides at any one place should not differ consider- 

 ably from year to year. 



(2) The tides at two places on the same, or very close, 

 latitude should be the same, or very nearly the same, however 

 far apart their places may be in longitude. 



(3) A place nearer the equator should have a higher tide 

 than one more remote. 



(4) There should be an agreement in amount at each place 

 with the corrected theoretical value for that latitude. 



From the actual results as tabulated the obvious con- 

 clusions are : — 



(1) The greatest variation for different years is, in almost 

 all cases, as great as, or greater than, the average tide at 

 that place ; since this variation must be due to causes other 

 than a moon-caused vibration, these other causes must be at 

 least of the same order of importance as the theoretical 

 one. 



(2) The average tides do not increase regularly towards 

 the equator, but roughly increase from the higher latitude 

 up to about 11°, and then diminish again towards the 

 equator. 



(3) The average observed height is always far in excess of 

 the corrected theoretical height, and, in fact, in the majority 

 of cases, is much nearer the uncorrected equilibrium value. 

 (It is worth noticing that the average of the actual tides for 

 all ports, allowing weight for the number of observations at 

 each, is about -95 of the average theoretical height, calculated 

 on the equilibrium theory and uncorrected. This is very 

 approximately the conclusion at which Professor Darwin 



