10. Powers thus make a great part of our complex ideas of particular substances.
Powers therefore justly make a
great part of our complex ideas of substances. He that will examine his complex idea of gold, will find several of
its ideas that make it up to be only powers; as the power of being melted, but of not spending itself in the fire; of
being dissolved in aqua regia, are ideas as necessary to make up our complex idea of gold, as its colour and
weight: which, if duly considered, are also nothing but different powers. For, to speak truly, yellowness is not
actually in gold, but is a power in gold to produce that idea in us by our eyes, when placed in a due light: and the
heat, which we cannot leave out of our ideas of the sun, is no more really in the sun, than the white colour it
introduces into wax. These are both equally powers in the sun, operating, by the motion and figure of its sensible
parts, so on a man, as to make him have the idea of heat; and so on wax, as to make it capable to produce in a man
the idea of white.
