power weak; hence the inhibitory
influence of the will is slight and the man gets angry easily. In the
phlegmatic temperament the anger-centres are slow to action, the
will-power strong, and the man is thrown off his balance with
difficulty. It is well known that power grows with exercise, and when we
habitually use the will in controlling the emotional centres its power
continually increases. The man learning self-control is simply drilling
the lower emotional centres into obedience to the repressive action of
the higher will. Without further demonstration, it is clear that emotion
is distinct from conscious will, and is automatic in the sense in which
the term has been used in this article.

Imagination also is plainly distinct from consciousness. It acts during
sleep. Often, indeed, it runs riot during the slumbers of the night, but
at times it works with an automatic regularity exceeding its powers
during the waking moments. It is also true that judgment is exercised in
sleep, and that reason sometimes exerts its best efforts in that state.
But not only do the intellectual nets go on without consciousness during
sleep, but also while we are awake. Some years since I was engaged in
working upon a book requiring a good deal of thought. Very frequently I
would be unable to solve certain problems, but leaving them would find a
day or two afterward, on taking pen in hand, that the solution traced
itself without effort on the paper clearly and logically. During the
sleeping hours, or during the waking hours of a busy professional life,
the brain had, without my consciousness, been solving the difficulties.
This experience is by no means a peculiar one. Many scientific workers
have borne testimony to a similar habit of the cerebrum. The late Sir W.
Rowan Hamilton, the discoverer of the mathematical method known as that
of the quaternions, states that his mind suddenly solved that problem
after long work when he was thinking of something else. He says in one
place: "Tomorrow will be the fifteenth birthday of the quaternions. They
started into life or light full grown on the 16th of October, 1843, as I
was walking with Lady Hamilton to Dublin and came up to Brougham Bridge;
that is to say, I then and there felt the galvanic circle of thought
closed, and the sparks which fell from it were the fundamental equations
between _I, F_ and _K_ exactly as I have used them ever since. I felt
the problem to have been at that moment solv