n of
other things which we might think about. A thousand and one objects are
possible to our thought at any moment, but all except one thing occupy a
secondary place, or are not present to our consciousness at all. They
exist on the margin, or else are clear off the edge of consciousness,
while the one thing occupies the center. We may be reading a fascinating
book late at night in a cold room. The charm of the writer, the beauty
of the heroine, or the bravery of the hero so occupies the mind that the
weary eyes and chattering teeth are unnoticed. Consciousness has piled
up in a high wave on the points of interest in the book, and the bodily
sensations are for the moment on a much lower level. But let the book
grow dull for a moment, and the make-up of the stream changes in a
flash. Hero, heroine, or literary style no longer occupies the wave.
They forfeit their place, the wave is taken by the bodily sensations,
and we are conscious of the smarting eyes and shivering body, while
these in turn give way to the next object which occupies the wave. Figs.
1-3 illustrate these changes.

[Illustration: FIG. 3]

CONSCIOUSNESS LIKENED TO A FIELD.--The consciousness of any moment has
been less happily likened to a field, in the center of which there is an
elevation higher than the surrounding level. This center is where
consciousness is piled up on the object which is for the moment foremost
in our thought. The other objects of our consciousness are on the margin
of the field for the time being, but any of them may the next moment
claim the center and drive the former object to the margin, or it may
drop entirely out of consciousness. This moment a noble resolve may
occupy the center of the field, while a troublesome tooth begets
sensations of discomfort which linger dimly on the outskirts of our
consciousness; but a shooting pain from the tooth or a random thought
crossing the mind, and lo! the tooth holds sway, and the resolve dimly
fades to the margin of our consciousness and is gone.

THE "PILING UP" OF CONSCIOUSNESS IS ATTENTION.--This figure is not so
true as the one which likens our mind to a stream with its ever onward
current answering to the flow of our thought; but whichever figure we
employ, the truth remains the same. Our mental energy is always piled up
higher at one point than at others. Either because our interest leads
us, or because the will dictates, the mind is withdrawn from the
thousand and one things we