ether the sensation ends as soon as the stimulus is
removed. If there is any after-image, is it positive or negative?

15. Tactile adaptation. Support two fingers on the edge of a table,
and lay on them a match or some other light object. Let this
stimulus remain there, motionless, and notice whether the tactile
sensation remains steady or dies out. What is the effect of making
slight movements of the fingers, and so causing the stimulus to
affect fresh parts of the skin?

16. Temperature sense adaptation. Have three bowls of water, one
quite warm, one cold, one medium. After holding one hand in the
warm water and the other in the cold, transfer both simultaneously
to the medium water and compare the temperature sensations got by
each hand from this water. State the result in terms of
adaptation.

17. Overtones. These can be quite easily heard in the sound of a
large bell. What use does the sense of hearing make of overtones?

REFERENCES
For a somewhat fuller discussion of the topic of sensation, see
Warren's _Human Psychology_, 1919, pp. 151-214; and for a much fuller
discussion, see Titchener's _Textbook of Psychology_, 1909, pp.
46-224.

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For a really thorough consideration of the facts and theories of color
vision, see J. Herbert Parsons, _An Introduction to the Study of
Colour Vision_, 1915.

For a more complete statement of the Ladd-Franklin theory, see the
article on "Vision", in Baldwin's _Dictionary of Philosophy and
Psychology_, 1902.

For a recent study that has revolutionized the psychology of the sense
of smell, see _Der Geruch_, by Hans Henning, 1916, or a review of the
same by Professor Gamble in the _American Journal of Psychology_,
1921, Vol. 32, pp. 290-296.

For an extensive discussion of the "Psychology of Sound", sec the book
with this title by Henry J. Watt, 1917.

For a full account of taste, see Hollingworth and Poffenberger's
_Sense of Taste_, 1917.

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CHAPTER XI

ATTENTION

HOW WE ATTEND, TO WHAT, AND WITH WHAT RESULTS

"Attention!" shouts the officer as a preliminary to some more specific
command, and the athletic starter calls out "Ready!" for the same
purpose. Both commands are designed to put the hearer in an attitude
of readiness for what is coming next. They put a stop to miscellaneous
doings and clear the way for the specific reaction that is next to be
called for. They nullify the effect of miscell