— 140 —
      §22. I have in what just goes before, been engaged in Physical
Enquiries a little farther than, perhaps, I intended. But it being
necessary, to make the Nature of Sensation a little understood, and
to make the difference between the Qualities in Bodies, and the Ideas
produced by them in the Mind, to be distinctly conceived, without
which it were impossible to discourse intelligibly of them; I hope,
I shall be pardoned this little Excursion into Natural Philosophy, it
being necessary in our present Enquiry, to distinguish the primary,
and real Qualities of Bodies, which are always in them, (viz. Solidity,
Extension, Figure, Number, and Motion, or Rest; and are some-
times perceived by us, viz. when the Bodies they are in, are big
enough singly to be discerned) from those secondary and imputed
Qualities, which are but the Powers of several Combinations of those
primary ones, when they operate, without being distinctly dis-
cerned; whereby we also may come to know what Ideas are, and
what are not Resemblances of something really existing in the
Bodies, we denominate from them.
Locke Hum II, 8, §22, p. 140