never be a dark-coloured yellow. The relationship between white
and yellow is as close as between black and blue, for blue can be
so dark as to border on black. Besides this physical
relationship, is also a spiritual one (between yellow and white
on one side, between blue and black on the other) which marks a
strong separation between the two pairs.

An attempt to make yellow colder produces a green tint and checks
both the horizontal and excentric movement. The colour becomes
sickly and unreal. The blue by its contrary movement acts as a
brake on the yellow, and is hindered in its own movement, till
the two together become stationary, and the result is green.
Similarly a mixture of black and white produces gray, which is
motionless and spiritually very similar to green.

But while green, yellow, and blue are potentially active, though
temporarily paralysed, in gray there is no possibility of
movement, because gray consists of two colours that have no
active force, for they stand the, one in motionless discord, the
other in a motionless negation, even of discord, like an endless
wall or a bottomless pit.

Because the component colours of green are active and have a
movement of their own, it is possible, on the basis of this
movement, to reckon their spiritual appeal.

The first movement of yellow, that of approach to the spectator
(which can be increased by an intensification of the yellow), and
also the second movement, that of over-spreading the boundaries,
have a material parallel in the human energy which assails every