the useful purpose of separating colors one from another,
as lead lines do in old cathedral windows, than which nothing more
beautiful has ever been devised.

Coming now to the consideration, not of differences, but similarities,
it is clear that a correspondence can be established between the
colors of the spectrum and the notes of a musical scale. That is,
the spectrum, considered as the analogue of a musical octave can
be subdivided into twelve colors which may be representative of
the musical chromatic scale of twelve semi-tones: the very word,
_chromatic_, being suggestive of such a correspondence between sound
and light. The red end of the spectrum would naturally relate to the
low notes of the musical scale, and the violet end to the high, by
reason of the relative rapidity of vibration in each case; for the
octave of a musical note sets the air vibrating twice as rapidly as
does the note itself, and roughly speaking, the same is true of the
end colors of the spectrum with relation to the ether.

But assuming that a color scale can be established which would yield
a color correlative to any musical note or chord, there still remains
the matter of _values_ to be dealt with. In the musical scale there is
a practical equality of values: one note is as potent as another. In
a color scale, on the other hand, each note (taken at its greatest
intensity) has a positive value of its own, and they are all
different. These values have no musical correlatives, they belong to
color _per se_. Every colorist knows that the whole secret of beauty
and brilliance dwells in a proper understanding and adjustment of
values, and music is powerless to help him here. Let us therefore
defer the discussion of this musical parallel, which is full of
pitfalls, until we have made some examination into such simple
emotional reactions as color can be discovered to yield. The musical
art began from the emotional response to certain simple tones and
combinations, and the delight of the ear in their repetition and
variation.

On account of our undeveloped sensitivity, the emotional reactions
to color are found to be largely personal and whimsical: one person
"loves" pink, another purple, or green. Color therapeutics is too
new a thing to be relied upon for data, for even though colors
are susceptible of classification as sedative, recuperative and
stimulating, no two classifications arrived at independently would be
likely to correspond. Most