n that of an engine running on rails. Steam automobiles and
traction engines are still confined to special purposes, the natures
of which prove that certain elements of adaptability are still lacking
in order to render them universally useful as are the locomotive and
the steam-ship.

In nearly every other important line of human needs and desires it
will be found that merely tentative efforts have been made by
ingenious minds resulting in inventions of greater or less promise.
Many of the finest conceptions which have necessarily been set down as
failures have missed fulfilling their intended missions, not so much
by reason of inherent weakness, as through the want of accessory
circumstances to assist them. As in biology, so in industrial progress
the definition of fitness appended to the law of the survival of the
fittest must have reference to the environment.

A foolish law or public prejudice results in the temporary failure of
a great invention, and the inventor's patent succumbs to the
inexorable operation of the struggle for existence. Yet, fortunately
for mankind, if not for the individual inventor, an idea does not
suffer extinction as the penalty for non-success in the struggle. "The
beginning of creation," says Carlyle, "is light," and the kind of
light which inventors throw upon the dark problems involving man's
industrial progress is providentially indestructible.

Twentieth century inventions--as the term is used in this book--are,
therefore, those which are destined to fulfil their missions during
the ensuing hundred years. They are those whose light will not only
exist in hidden places, but will also shine abroad to help and to
bless mankind. Or, if we may revert to the former figure, they are
those which have not only been planted in the seed and have germinated
in the leaf, but which have grown to goodly proportions, so that none
may dare to assert that they have been planted for nought. A man's age
is the age in which he does his work rather than that in which he
struggles to years of maturity. Moore and Byron were poets of the
nineteenth century, although the one had attained to manhood and the
other had grown from poverty to inherit a peerage before the new
century dawned.

The prophetic role--although proverbially an unsafe one--is
nevertheless one which every business man must play almost every day
of his life. The merchant, the manufacturer, the publisher, the
director, the manager, and eve