melody, which is pure succession. This fundamental difference between
time and space cannot be over-emphasized. A musical note prolonged,
becomes at last scarcely tolerable; while a beautiful color, like the
blue of the sky, we can enjoy all day and every day. The changing hues
of a sunset, are _andante_ if referred to a musical standard, but to
the eye they are _allegretto_--we would have them pass less swiftly
than they do. The winking, chasing, changing lights of illuminated
sky-signs are only annoying, and for the same reason. The eye longs
for repose in some serene radiance or stately sequence, while the ear
delights in contrast and continual change. It may be that as the eye
becomes more educated it will demand more movement and complexity, but
a certain stillness and serenity are of the very nature of light,
as movement and passion are of the very nature of sound. Music is a
seeking--"love in search of a word"; light is a finding--a "divine
covenant."

With attention still focussed on the differences rather than the
similarities between the musical art and a new art of mobile color,
we come next to the consideration of the matter of form. Now form
is essentially of space: we speak about the "form" of a musical
composition, but it is in a more or less figurative and metaphysical
sense, not as a thing concrete and palpable, like the forms of space.
It would be foolish to forego the advantage of linking up form with
colour, as there is opportunity to do. Here is another golden ball to
juggle with, one which no art purely in time affords. Of course it is
known that musical sounds weave invisible patterns in the air, and to
render these patterns perceptible to the eye may be one of the more
remote and recondite achievements of our uncreated art. Meantime,
though we have the whole treasury of natural forms to draw from, of
these we can only properly employ such as are _abstract_. The reason