BOOK I PART II
before it appeared greater than another. Nor
is this the only correction, which these judg-
ments of our senses undergo; but we often dis-
cover our error by a juxtaposition of the objects;
or where that is impracticable, by the use of
some common and invariable measure, which
being successively applied to each, informs us
of their different proportions. And even this
correction is susceptible of a new correction,
and of different degrees of exactness, accord-
ing to the nature of the instrument, by which
we measure the bodies, and the care which we
employ in the comparison.
When therefore the mind is accustomed to
these judgments and their corrections, and
finds that the same proportion which makes
two figures have in the eye that appearance,
which we call equality, makes them also corre-