In the preceding chapters the progress of light has been sketched from its obscure infancy to its vigorous youth of the present time. It has been seen that progress was slow until the beginning of the nineteenth century, after which it began to gain momentum until the present century has witnessed tremendous advances. Until the latter part of the nineteenth century artificial light was considered an expensive utility, but as modern lamps appeared which supplied adequate light at reasonable cost attention began to be centered upon utilization, and the lighting engineer was born. Gradually it is being realized that artificial light is no longer a luxury, that it may be used in great quantity, and that it may be directed, diffused, and altered in color as desired. Although the potentiality of light has been barely drawn upon, the present usages surpass the most extravagant dreams of civilized beings a half-century ago. Mere light of that time was changed into more light as gas-lighting developed, and more light has increased to adequate light of the present time through the work of scientists. It is apparent that a sudden enforced reversion to the primitive flames of fifty years ago would paralyze many activities. Much of interest and beauty would be blotted out of this brilliant, pulsating, productive age. It is startling to note that almost the entire progress in artificial lighting has taken place during the past hundred years and that most of it has been crowded into the latter part of this period. In fact, its development since it began in earnest has gone forward with ever-increasing momentum. On viewing the wonders of modern artificial lighting on every hand it is not difficult to muster the courage necessary to venture into its future. The lighting engineer has been a natural evolution of the present age, for the economic aspects of lighting have demanded attention. He is increasing the safety, efficiency, and happiness of mankind and civilization is beginning to feel his influence economically. However, with the advent of adequate, efficient, and controllable light, the potentiality of light as an artistic medium may be drawn upon and the lighting artist with a deep insight into the possibilities of artificial light now has his opportunity. But the artist who believes that a new art may be evolved to perfection in a few years is doomed to disappointment, for it is necessary only to view retrospectively such arts as painting and music to be convinced that understanding and appreciation develop slowly through centuries of experiment and contact.