The difficulty appears to consist in the inferior impressionability of the eye to its particular order of beauty.  To the average man color—­as color—­has nothing significant to say:  to him grass is green, snow is white, the sky blue; and to have his attention drawn to the fact that sometimes grass is yellow, snow blue, and the sky green, is disconcerting rather than illuminating.  It is only when his retina is assaulted by some splendid sunset or sky-encircling rainbow that he is able to disassociate the idea of color from that of form and substance.  Even the artist is at a disadvantage in this respect, when compared with the musician.  Nothing in color knowledge and analysis analogous to the established laws of musical harmony is part of the equipment of the average artist; he plays, as it were, by ear.  The scientist, on the other hand, though he may know the spectrum from end to end, and its innumerable modifications, values this “rainbow promise of the Lord” not for its own beautiful sake but as a means to other ends than those of beauty.  But just as the art of music has developed the ear into a fine and sensitive instrument of appreciation, so an analogous art of light would educate the eye to nuances of color to which it is now blind.

[Illustration:  PLATE XIV.  SONG AND LIGHT:  AN APPROACH TOWARD “COLOR MUSIC”]

It is interesting to speculate as to the particular form in which this new art will manifest itself.  The question is perhaps already answered in the “color organ,” the earliest of which was Bambridge Bishop’s, exhibited at the old Barnum’s Museum—­before the days of electric light—­and the latest A.W.  Rimington’s.  Both of these instruments were built upon a supposed correspondence between a given scale of colors, and the musical chromatic scale; they were played from a musical score upon an organ keyboard.  This is sufficiently easy and sufficiently obvious, and has been done, with varying success in one way or another, time and again, but its very ease and obviousness should give us pause.

It may well be questioned whether any arbitrary and literal translation, even though practicable, of a highly complex, intensely mobile art, unfolding in time, as does music, into a correspondent light and color expression, is the best approach to a new art of mobile color.  There is a deep and abiding conviction, justified by the history of aesthetics, that each art-form must progress from its own beginnings and unfold in its own unique and characteristic way.  Correspondences between the arts—­such a correspondence, for example, as inspired the famous saying that architecture is frozen music—­reveal themselves usually only after the sister arts have attained an independent maturity.  They owe their origin to that underlying unity upon which our various modes of sensuous perception act as a refracting medium, and must therefore be taken for granted.  Each art, like each individual, is unique and singular; in this singularity dwells its most thrilling appeal.  We are likely to miss light’s crowning glory, and the rainbow’s most moving message to the soul if we preoccupy ourselves too exclusively with the identities existing between music and color; it is rather their points of difference which should first be dwelt upon.