. There is no longer
any need for human labor in the sense of personal toil, for the physical
energy necessary to accomplish all kinds of work may be obtained from
external sources and it can be directed and controlled without extreme
exertion. Man's first effort in this direction was to throw part of his
burden upon the horse and ox or upon other men. But within the last
century it has been discovered that neither human nor animal servitude
is necessary to give man leisure for the higher life, for by means of
the machine he can do the work of giants without exhaustion. But the
introduction of machines, like every other step of human progress, met
with the most violent opposition from those it was to benefit. "Smash
'em!" cried the workingman. "Smash 'em!" cried the poet. "Smash 'em!"
cried the artist. "Smash 'em!" cried the theologian. "Smash 'em!" cried
the magistrate. This opposition yet lingers and every new invention,
especially in chemistry, is greeted with general distrust and often with
legislative prohibition.

Man is the tool-using animal, and the machine, that is, the power-driven
tool, is his peculiar achievement. It is purely a creation of the human
mind. The wheel, its essential feature, does not exist in nature. The
lever, with its to-and-fro motion, we find in the limbs of all animals,
but the continuous and revolving lever, the wheel, cannot be formed of
bone and flesh. Man as a motive power is a poor thing. He can only
convert three or four thousand calories of energy a day and he does that
very inefficiently. But he can make an engine that will handle a hundred
thousand times that, twice as efficiently and three times as long. In
this way only can he get rid of pain and toil and gain the wealth he
wants.

Gradually then he will substitute for the natural world an artificial
world, molded nearer to his heart's desire. Man the Artifex will
ultimately master Nature and reign supreme over his own creation until
chaos shall come again. In the ancient drama it was _deus ex machina_
that came in at the end to solve the problems of the play. It is to the
same supernatural agency, the divinity in machinery, that we must look
for the salvation of society. It is by means of applied science that the
earth can be made habitable and a decent human life made possible.
Creative evolution is at last becoming conscious.

II

NITROGEN

PRESERVER AND DESTROYER OF LIFE

In the eyes of the chemist the Great