300. On this Theory so far as we have explained it, the Tides ought to
be highest directly under and opposite to the Moon; that is, when the
Moon is due north and south. But we find, that in open Seas, where the
water flows freely, the Moon _M_ is generally past the north and south
Meridian as at _p_ when it is high water at _Z_ and at _n_. The reason
is obvious; for though the Moon’s attraction was to cease altogether
when she was past the Meridian, yet the motion of ascent communicated to
the water before that time would make it continue to rise for some time
after; much more must it do so when the attraction is only diminished:
as a little impulse given to a moving ball will cause it still move
farther than otherwise it could have done. And as experience shews, that
the day is hotter about three in the afternoon, than when the Sun is on
the Meridian, because of the increment made to the heat already
imparted.
[Sidenote: Nor always answer to her being at the same distance from it.]
301. The Tides answer not always to the same distance of the Moon from
the Meridian at the same places; but are variously affected by the
action of the Sun, which brings them on sooner when the Moon is in her
first and third Quarters, and keeps them back later when she is in her
second and fourth: because, in the former case, the Tide raised by the
Sun alone would be earlier than the Tide raised by the Moon; and in the
latter case later.
[Sidenote: Spring and neap Tides.