extinguishing the light and pondering upon his helplessness in the
resulting darkness, man may gain an idea of its overwhelming importance.
Those unfortunate persons who suffer the terrible calamity of blindness
after years of dependence upon sight will testify in heartrending terms
to the importance of light. Milton, whose eyesight had failed, laments,

O first created beam and thou great Word
"Let there be light," and light was over all,
Why am I thus bereaved thy prime decree?

Perhaps only through a similar loss would one fully appreciate the
tremendous importance of light to him, but imagination should be capable
of convincing him that it is one of the most essential and
pleasure-giving phenomena known to mankind.

A retrospective view down the vista of centuries reveals by contrast the
complexity with which artificial light is woven into human activities of
the present time. Written history fails long before the primitive races
are reached, but it is safe to trust the imagination to penetrate the
fog of unwritten history and find early man huddled in his cave as
daylight wanes. Impelled by the restless spirit of progress, this
primitive being grasped the opportunity which fire afforded to extend
his activities beyond the boundaries of daylight. The crude art upon the
walls of his cave was executed by the flame of a smoking fagot. The fire
on the ledge at the entrance to his abode became a symbol of home, as
the fire on the hearth has symbolized home and hospitality throughout
succeeding ages. The accompanying light and the protection from cold
combined to establish the home circle. The ties of mated animals
expanded through these influences to the bonds of family. Thus light was
woven early into family life and has been throughout the ages a