— 139 —
      §21. Ideas being thus distinguished and understood, we may be
able to give an Account, how the same Water, at the same time,
may produce the Idea of Cold by one Hand, and of Heat by the
other: Whereas it is impossible, that the same Water, if those Ideas
were really in it, should at the same time be both Hot and Cold. For
if we imagine Warmth, as it is in our Hands, to be nothing but a
certain sort and degree of Motion in the minute Particles of our Nerves, or
animal Spirits, we may understand, how it is possible, that the same
Water may at the same time produce the Sensation of Heat in one
Hand, and Cold in the other; which yet Figure never does, that
never producing the Idea of a square by one Hand, which has pro-
duced the Idea of a Globe by another. But if the Sensation of Heat
and Cold, be nothing but the increase or diminution of the motion
of the minute Parts of our Bodies, caused by the Corpuscles of any
other Body, it is easie to be understood, That if that motion be
greater in one Hand, than in the other; if a Body be applied to the
two Hands, which has in its minute Particles a greater motion,
than in those of one of the Hands, and a less, than in those of the
other, it will increase the motion of the one Hand, and lessen it in
the other, and so cause the different Sensations of Heat and Cold,
that depend thereon.
Locke Hum II, 8, §21, p. 139