esses of the present time.

The end is not in sight and perhaps never will be. The unexplored region
extends to infinity and, judged by the past, the momentum of discovery
will continue to increase for ages to come, unless the human race decays
through the comfort and ease gained from utilizing the magic secrets
which are constantly being wrested from nature. Among the achievements
of science and invention, the production and application of artificial
light ranks high. As an influence upon civilization, no single
achievement surpasses it.

Without artificial light, mankind would be comparatively inactive about
one half its lifetime. To-day it has been fairly well established that
the human organism can flourish on eight hours' sleep in a period of
twenty-four hours. Another eight hours spent in work should settle man's
obligation to the world. The remaining hours should be his own.
Artificial light has made such a distribution of time possible. The
working-periods in many cases may be arranged in the interests of
economy, which often means continuous operations. The sun need not be
considered when these operations are confined to interiors or localized
outdoors.

Thus, artificial light has been an important factor in the great
industrial development of the present time. Man now burrows into the
earth, navigates under water, travels upon the surface of land and sea,
and soars among the clouds piloted by light of his own making. Progress
does not halt at sunset but continues twenty-four hours each day.
Building, printing, manufacturing, commerce, and other activities are
prosecuted continuously, the working-shifts changing at certain periods
regardless of the rising or setting sun. Adequate artificial lighting
decreases spoilage, increases production, and is a powerful factor in
the prevention of industrial accidents.

It has ever been true since the advent of artificial light that the
intellect has been largely nourished after the completion of the day's
work. The highly developed artificial lighting of the present time may
account for much of the vast industry of publication. Books, magazines,
and newspapers owe much to convenient and inexpensive artificial light,
for without it fewer hours would be available for recreation and
advancement through reading. Schools, libraries, and art museums may be
attended at night for the betterment of the human race. The immortal
Lincoln, it is said, gained his early education la