all that can be said is that actual experience of it is the only satisfactory reply to the question.
It would seem that what really take the place of the additional interest which form gives to fixed or stationary colour are the elements of change and of rhythm which a mobile colour system introduces.
The increase in the desire for rapid changes contrasting with slower ones, already several times referred to, seems to point to this conclusion, and form, in the sense in which the musician uses the word in speaking of a musical composition, gradually enters into or attaches itself to the colour in the mind of the spectator.
There will always be a certain number of people who perhaps having little natural liking either for music or for colour—or who, caring much for music, have little feeling for other forms of art—will ask whether mobile colour has any "practical objects," or whether it can be turned to any "practical use." They ask this in all sincerity and with no desire to be hypercritical. The question has, to a certain extent, already been dealt with, but may be
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