, therefore, we perceive no succession at
all.

11. In slow motions.

This also happens where the motion is so slow as not to supply a
constant train of fresh ideas to the senses, as fast as the mind is
capable of receiving new ones into it; and so other ideas of our own
thoughts, having room to come into our minds between those offered to
our senses by the moving body, there the sense of motion is lost; and
the body, though it really moves, yet, not changing perceivable distance
with some other bodies as fast as the ideas of our own minds do
naturally follow one another in train, the thing seems to stand still;
as is evident in the hands of clocks, and shadows of sun-dials, and
other constant but slow motions, where, though, after certain intervals,
we perceive, by the change of distance, that it hath moved, yet the
motion itself we perceive not.

12. This Train, the Measure of other Successions.

So that to me it seems, that the constant and regular succession of
IDEAS in a waking man, is, as it were, the measure and standard of all
other successions. Whereof if any one either exceeds the pace of our
ideas, as where two sounds or pains, &c., take up in their succession
the duration of but one idea; or else where any motion or succession is
so slow, as that it keeps not pace with the ideas in our minds, or the
quickness in which they take their turns, as when any one or more ideas
in their ordinary course come into our mind, between those which are
offered to the sight by the different perceptible distances of a body in
motion, or between sounds or smells following one another,--there also
the sense of a constant continued succession is lost, and we perceive it
not, but with certain gaps of rest between.

13. The Mind cannot fix long on one invariable Idea.

If it be so, that the ideas of our minds, whilst we have any there,
do constantly change and shift in a continual succession, it would be
impossible, may any one say, for a man to think long of any one thing.
By which, if it be meant that a man may have one self-same single idea a
long time alone in his mind, without any variation at all, I think, in
matter of fact, it is not possible. For which (not knowing how the ideas
of our minds are framed, of what materials they are made, whence they
have their light, and how they come to make their appearances) I can
give no other reason but experience: and I would have any one try,
whether he can keep one unva