1902 Encyclopedia > Tides > [Synthetic Method] Diurnal Tides
(Part 32)   32. Diurnal Tides  These tides have not been usually
treated with completeness in the synthetic method. In the tide-
tables of the British Admiralty we find that the tides at some
ports are "affected by diurnal inequality"; such a statement may
be interpreted as meaning that the tides are not to be predicted
by the information given in the so-called tide-table. The
diurnal tides are indeed complex, and do not lend themselves
easily to a complete synthesis. In the harmonic notation the
three important tides are K1, O, P, and the lunar portion of K1
is nearly equal to O in height, whilst the solar portion is
nearly equal to P. A complete synthesis may be carried out on
the lines adopted in treating the semi-diurnal tides, but the
advantage of the plan is lost in consequence of large
oscillations of the amplitude through the value zero, so that
the tide is often represented by a negative quantity multiplied
by a circular function. It is bes