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 largely by the light of the fireplace.  But all were not endowed with the persistence of Lincoln, so that illiteracy was more common in his day than in the present age of adequate illumination.

The theatrical stage not only depends for its effectiveness upon artificial light but owes its existence and development largely to this agency.  In the moving-picture theater, pictures are projected upon the screen by means of it and even the production of the pictures is independent of daylight.  These and a vast number of recreational activities owe much, and in some cases their existence, to artificial light.

Not many centuries ago the streets at night were overrun by thieves and to venture outdoors after dark was to court robbery and even bodily harm.  In these days of comparative safety it is difficult to realize the influence that abundant illumination has had in increasing the safety of life and property.  Maeterlinck in his poetical drama, “The Bluebird,” appropriately has made Light the faithful companion of mankind.  The Palace of Night, into which Light is not permitted to enter, is the abode of many evils.  Thus the poet has played upon the primitive instincts of the impressiveness of light and darkness.

By combining the symbolism of light, color, and darkness with the instincts which have been inherited by mankind from its superstitious ancestry of the age of mythology, another field of application of artificial light is opened.  Light has gradually assumed such attributes as truth, knowledge, progress, enlightenment.  Throughout the early ages light was more or less worshiped and thus artificial lights became woven in many religious