unfitted by natural aptitudes or by training.

The man who is trying to do work for which he is unfitted feels repressed,
baffled and defeated. He may not even guess his unfitness, but he does
feel its manifold effect. He lacks interest in his work and, therefore,
that most vital factor in personal efficiency--incentive. He cannot throw
himself into his work with a whole heart.

When Thomas A. Edison is bent upon realizing one of his ideas, his
absorption in his work exemplifies Emerson's dictum: "Nothing great was
ever accomplished without enthusiasm. The way of life is wonderful--it is
by abandonment." He shuts himself away from all interruption in his
laboratory; he works for hours oblivious of everything but his idea. Even
the demands of his body for food and sleep do not rise above the threshold
of consciousness.

Edison himself says that great achievement is a result, not of genius,
but of this kind of concentration in work--and, until the mediocre man has
worked as has Edison, he cannot prove the contrary. Mr. Edison has results
to prove the value of his way of working. Even our most expert
statisticians and mathematicians would find it difficult to calculate,
accurately, the amount of material wealth this one worker has added to
humanity's store. Of the unseen but higher values in culture, in
knowledge, in the spread of civilization, and in greater joy of living for
millions of people, there are even greater riches. Other men of the past
and present, in every phase of activity, have demonstrated that such an
utter abandonment to one's tasks is the keynote of efficiency and
achievement. But such abandonment is impossible to the man who is doing
work into which he cannot throw his best and greatest powers--which claims
only his poorest and weakest.