There are many to whom it at once provides a surpassingly interesting source of enjoyment and education, and some to whom, like my medical friend, it will open up an entirely new world of sensations; and there are others, again, to whom it will be supremely distasteful. It is well to recognize this to avoid disappointment, and be prepared for very divergent expressions of opinion about it. Speaking broadly, it appeals most to those who have had an artistic training into which color has entered, and it is less attractive to those whose interests center in music. This is not what the author personally expected. He imagined that the connection with music being so close on some points, those who would take the greatest interest in mobile color would be musicians; but, with some striking exceptions among distinguished musicians, the musical world, as far as it has yet come into contact with color-music, has been at first inclined to see points of divergence rather than those of analogy and to look upon the art as a possible rival. A similar attitude is often adopted toward any new departure in science or art, and there is no reason for resenting it; it merely makes the cooperation of those among musicians who are able to take a sympathetic view and welcome the endeavor to open up new fields of investigation all the more valuable. * * * * * From time immemorial child and man have taken the keenest delight in fireworks and colored lights which are after all a species of light music. Since the adoption of electricity for lighting it is comparatively easy to produce the most wonderful effects both indoors and out. As yet little thought has been given to producing harmonious light effects on streets--save in advertising signs. For the most part the lighting is garish in the extreme, often positively painful to the eyes, but in time this will be corrected. Public authorities cooperating with private owners will work out schemes for lighting streets and shops that will yield charming effects. * * * * * Already much has been done in the theater, especially in Russia and Germany. The value of light effects is being recognized. Soft music is often played to enhance the effect of a tender or pathetic scene, and it is quite common for the lights to change in harmony. By the use of light alone as an accompaniment to a love scene the same effect on the audience can be secured as by the use of soft music. So far all this has been done crudely and for the most part unscientifically. Producer and electrician have worked together in a haphazard way, often with great success, sometimes with most disagreeable results.