aracter knows what an effort this is, even
if he is talking with persons whom he has known for years, and
with whose mental and lingual characteristics he is well acquainted:
and he also knows how much more difficult it is when he is talking
with persons whom he knows but slightly.

It may here be pointed out how greatly the imaginations of men
differ, and how little account is taken of this difference in every-day
life. In poetry and fiction imagination is recognized; and it is
also recognized to some extent in painting, inventing, and, in
general, in "the arts." But in ordinary life, the difference among
men in imagination is almost never noticed. Yet a French proverb
is "point d'imagination, point de grand general"; and Napoleon
indicated a danger from untrained imagination in his celebrated
warning to his generals not to make "pictures" to themselves of
difficulties and disasters.

The difference in imagination among men is shown clearly by the
difference--and often the differences--between inventors and engineers,
and the scarcity of men who are both inventors and engineers. Ericsson
repudiated the suggestion that he was an inventor, and stoutly and
always declared he was an engineer. This was at a time, not very
long ago, when it was hardly respectable to be an inventor; when,
even though men admitted that some inventors had done valuable work,
the work was supposed to be largely a chance shot of a more or less
crazy man. Yet Ericsson was an inventor--though he was an engineer.
So were Sir William Thompson (afterward Lord Kelvin), Helmholtz,
Westinghouse, and a very few others; so are Edison and Sperry.
Many inventors, however, live in their imaginations mainly--some
almost wholly. Like Pegasus, they do not like to be fastened to a
plough or anything else material. Facts, figures, and blue-prints
fill their souls with loathing, and bright generalities delight them.
The engineer, on the other hand, is a man of brass and iron and
logarithms; in imagination he is blind, in flexibility he resembles
reinforced concrete. He is the antipodes of the inventor; he despises
the inventor, and the inventor hates him. Fortunately, however,
there is a little bit of the inventor in most engineers, and a
trace of the engineer in most inventors; while in some inventors
there is a good deal of the engineer. And once in a while we meet
a man who carries both natures in his brain. That man does marvels.

Despite the great gulf nor