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 formulæ for determining
the establishnent, 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
uggestions 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 phænomena in the tides which have been considered as cases of interference. Mr. Whewell was led, from certain remarkable changes in the epoch of this phæno- 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-
