feeling of seeing a blue color. [Footnote: Dr. Freudenberg.
"Spaltung der Personlichkeit" (Ubersinnliche Welt. 1908. No. 2,
p. 64-65). The author also discusses the hearing of colour, and
says that here also no rules can be laid down. But cf. L.
Sabanejeff in "Musik," Moscow, 1911, No. 9, where the imminent
possibility of laying down a law is clearly hinted at.] It would
be possible to suggest, by way of explanation of this, that in
highly sensitive people, the way to the soul is so direct and the
soul itself so impressionable, that any impression of taste
communicates itself immediately to the soul, and thence to the
other organs of sense (in this case, the eyes). This would imply
an echo or reverberation, such as occurs sometimes in musical
instruments which, without being touched, sound in harmony with
some other instrument struck at the moment.

But not only with taste has sight been known to work in harmony.
Many colours have been described as rough or sticky, others as
smooth and uniform, so that one feels inclined to stroke them
(e.g., dark ultramarine, chromic oxide green, and rose madder).
Equally the distinction between warm and cold colours belongs to
this connection. Some colours appear soft (rose madder), others
hard (cobalt green, blue-green oxide), so that even fresh from
the tube they seem to be dry.

The expression "scented colours" is frequently met with. And
finally the sound of colours is so definite that it would be hard
to find anyone who would try to express bright yellow in the bass
notes, or dark lake in the treble.

[Footnote: Much theory and practice have been devoted to this