BOOK I PART II
time alone ever to make its appearance, or be
taken notice of by the mind. A man in a sound
sleep, or strongly occupyed with one thought,
is insensible of time; and according as his per-
ceptions succeed each other with greater or
less rapidity, the same duration appears longer
or shorter to his imagination. It has been re-
marked by a great philosopher, that our per-
ceptions have certain bounds in this particu-
lar, which are fixed by the original nature and
constitution of the mind, and beyond which
no influence of external objects on the senses
is ever able to hasten or retard our thought. If
you wheel about a burning coal with rapidity,
it will present to the senses an image of a cir-
cle of fire; nor will there seem to be any in-
terval of time betwixt its revolutions; meerly
because it is impossible for our perceptions to
succeed each other with the same rapidity, that