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laborious investigations which have led to its establishment, but 

 which are no longer necessary for its explanation or proof. This 

 observation may be applied, in some degree, to his very ingenious 

 Memoir " On the Empirical Laws of the Port of London", in which 

 he attempts to deduce from observation and from very simple ge- 

 neral considerations, the character of the formulae for determining 

 the establishment, the semimenstrual inequality, the corrections for 

 lunar and solar parallax and declination, both as affecting the times 

 and the height of high water. Similar observations may be ex- 

 tended to his papers on the " Empirical Laws of the Tides of the 

 Port of Liverpool," and also on the " solar inequality and diurnal 

 inequality" of the tides at the same place, which are full of valuable 

 suggestions which the subsequent investigations of Mr. Lubbock 

 have, in some cases, very remarkably confirmed and extended. 



The last of the series of researches of Mr. Whewell relate to the 

 diurnal inequality of the height of the tide, which the discussion of 

 the tides at Liverpool had exhibited, though under circumstances 

 much less striking than those which characterize its appearance in 

 other places. The first of his memoirs on this subject relates to the 

 diurnal inequality at Plymouth and Sincapore, at the last of which 

 places its magnitude is very remarkable, making a difference of not 

 less than six feet in the height of morning and evening tide, and quite 

 sufficient to obliterate, under certain circumstances, one of the semi- 

 diurnal tides, and explaining certain phsenomena in the tides which 

 have been considered as cases of interference. Mr. Whewell was 

 led, from certain remarkable changes in the epoch of this pheeno- 

 menon, which seemed to be deducible from the observations at Bris- 

 tol, Liverpool and Leith, to suspect that its progress along the coasts 

 of Europe and Great Britain was retarded according to some regular 

 law. His subsequent discussion, however, of the .simultaneous ob- 

 servations made in June, 1835, with an especial view to this in- 

 equality, showed that the differences of diurnal inequality were go- 

 verned by local causes, and consequently negatived altogether the 

 hypothesis of its progressive propagation according to a law distinct 

 from that of the other inequalities of the tides. 



The preceding abstract of Mr. Whewell's Researches on the Tides 

 is necessarily very brief and imperfect, and little calculated to con- 

 vey to the minds of those who have not read his very extensive series 

 of memoirs an adequate notion of the amount of labour and of 

 thought which the discussion of such extensive series of observa- 

 tions must have required. 



The importance of the results which have been obtained by him 

 and Mr. Lubbock, may be best estimated by the rapid advancement 

 which has been made in our knowledge of the laws which regulate 

 the movements of the tides during the last six years, and which is 

 entirely owing to their joint labours. Theory, though little culti- 

 vated and little known, was then in advance of observation : tide 

 tables were constructed by unpublished rules, which formed a pro- 

 fitable possession to those to whom the secret was known : and the 

 distinctive characters of the tides in the different ports of this king- 



