have the faculty it will be borne in on you how other men will
feel on your subject. The skill of politicians, where it does not
confine itself to estimating how much the people will stand before
rebelling, consists in this intuition of the movement of public opinion;
and the great leaders are the men who have so sure a sense of these
large waves of popular feeling that they can utter at the right moment
the word that will gather together this diffused and uncrystallized
feeling into a living force. Lincoln's declaration, "A house divided
against itself cannot stand, I believe that this government cannot
endure permanently half slave and half free," brought to a head a
conflict that had been smoldering ever since the adoption of the
Constitution, and made him the inevitable leader who was to bring it to
a close. It will be noticed, however, that the time had to come before
the inspired word could make its appeal. The abolitionists and
antislavery men had long been preaching the same doctrine that Lincoln
uttered, and the folly and wickedness of slavery had been proved by
philosophers and preachers for generations. Until the time grows ripe
the most reasonable doctrine does not touch the hearts of men; when the
time has ripened, the leader knows it and speaks the word that sets the
world on fire for righteousness.

The same faculty, on a smaller scale, is needed by every one of us who
is trying to make other people do anything. The actual use of the
faculty will vary greatly, however, with different kinds of arguments.
In certain kinds of scientific argument any attempt at persuasion as
such would be an impertinence: whether heat is a mode of motion, whether
there are such infinitesimal bodies as the ions which physicists of
to-day assume to explain certain new phenomena, whether matter consists
of infinitesimal whirls of force--in all such questions an argument
appeals solely to the reason; and in such Bacon's favorite apophthegm
has full sway, Dry light is ever the best. In Huxley's arguments for the
theory of evolution feeling had some share, for when the theory was
first announced by Darwin some religious people thought that it cut at
the foundations of their faith, and Huxley had to show that loyalty to
truth is a feeling of equal sanctity to scientific men: hence there is
some tinge of feeling, though repressed, in his argument, and a definite
consciousness of the feelings of his audience.

At the other extreme a