13. How secondary qualities produce their ideas.
After the same manner, that the ideas of these original qualities
are produced in us, we may conceive that the ideas of secondary qualities are also produced, viz., by the operation
of insensible particles on our senses. For, it being manifest that there are bodies and good store of bodies, each
whereof are so small, that we cannot by any of our senses discover either their bulk, figure, or motion,--as is
evident in the particles of the air and water, and others extremely smaller than those; perhaps as much smaller
than the particles of air and water, as the particles of air and water are smaller than peas or hail-stones;--let us
suppose at present that the different motions and figures, bulk and number, of such particles, affecting the several
organs of our senses, produce in us those different sensations which we have from the colours and smells of
bodies; v.g. that a violet, by the impulse of such insensible particles of matter, of peculiar figures and bulks, and
in different degrees and modifications of their motions, causes the ideas of the blue colour, and sweet scent of that
flower to be produced in our minds. It being no more impossible to conceive that God should annex such ideas to
such motions, with which they have no similitude, than that he should annex the idea of pain to the motion of a
piece of steel dividing our flesh, with which that idea hath no resemblance.
