h concerned to heed it,
whereof more will be said by and by;) that we should rather assign the
beginnings of _February_ and _November_, than the two _AEquinoxes_.

Now in order to the giving account of these three Periods, according to the
_Laws of Motion_ and _Mechanick Principles_; We shall _first_ take for
granted, what is now adayes pretty commonly entertained by those, who treat
of such matters; _That a Body in motion is apt to continue its motion, and
that in the same degree of celerity, unless hindred by some contrary
Impediment_; (like as a Body at rest, to continue so, unless by some
sufficient mover, put into motion:) And accordingly (which daily experience
testifies) if on a Board or Table, some loose incumbent weight, be for some
time moved, & have thereby contracted an _Impetus_ to motion at such a
rate; if that Board or Table chance by some external obstacle, or
otherwise, to be stopped or considerably retarded in its motion, the
incumbent loose Body will shoot forward upon it: And contrarywise, in case
that Board or Table chance to be accelerated or put forward with a
considerably greater speed than before, the loose incumbent Body, (not
having yet obtained an equal _Impetus_ with it) will be left behind, or
seem to fly backward upon it. Or, (which is _Galilaeo_'s instance,) if a
broad Vessel of Water, for some time evenly carried forward with the water
in it, chance to meet with a stop, or to slack its motion, the Water will
dash forward and rise higher at the fore part of the Vessel: And,
contrarywise, if the Vessel be suddenly put forward faster than before; the
Water will dash backwards, and rise at the hinder part of the Vessel. So
that an Acceleration or Retardation of the Vessel, which carries it, will
cause a rising of the Water in one part, and a falling in another: (which
yet, by its own weight, will again be reduced to a Level as it was before.)
And consequently, supposing the Sea to be but as a loose Body, carried
about with the Earth, but not so united with it, as necessarily to receive
the same degree of _Impetus_ with it, as its fixed parts do: The
acceleration or retardation in the motion of this or that part of the
Earth, will cause (more or less, according to the proportion of it) such a
dashing of the Water, or rising at one part, with a Falling at another, as
is that, which we call the Flux and Reflux of the Sea. {269}

[Illustration]

Now this premised, We are next, with him, to supp