imitate them with crayons, paints, and colored
stuffs, so as to test the growth of perception, and learn by simple yet
accurate terms to describe each by its hue, its value, and its chroma.

(28) Pigments, rather than the solar spectrum, are the practical agents
of color work. Certain of them, selected and measured by this system
(see Chapter V.), will be known as MIDDLE COLORS, because they stand
midway in the scales of value and chroma. These middle colors are
preserved in imperishable enamels,[9] so that the child may handle and
fix them in his memory, and thus gain a permanent basis for comparing
all degrees of color. He learns to grade each middle color to its
extremes of value and chroma.

[Footnote 9: When recognized for the first time, a middle green,
blue, or purple, is accepted by most persons as well within
their color habit, but middle red and middle yellow cause
somewhat of a shock. "That isn't red," they say, "it's terra
cotta." "Yellow?" "Oh, no, that's--well, it's a very peculiar
shade."
Yet these are as surely the middle degrees of red and yellow as
are the more familiar degrees of green, blue, and purple. This
becomes evident as soon as one accepts physical tests of color
in place of personal whim. It also opens the mind to a generally
ignored fact, that middle reds and yellows, instead of the
screaming red and yellow first given a child, are constantly
found in examples of rich and beautiful color, such as Persian
rugs, Japanese prints, and the masterpieces of painting.]

(29) Experiments with crayons and paints, and efforts to match middle
colors, train his color sense to finer perceptions. Having learned to
name colors, he compares them with the enamels of middle value, and can
describe how light or dark they are. Later he perceives their
differences of strength, and, comparing them with the enamels of middle
chroma, can describe how weak or strong they are. Thus the full
significance of these middle colors as a practical basis for all color
estimates becomes apparent; and, when at a more advanced stage he
studies the best examples of decorative color, he will again encounter
them in the most beautiful products of Oriental art.

+Is it possible to define the endless varieties of color?+

(30) At first glance it would seem almost hopeless to attempt the naming
of every kind and degree of color. But, if all these varieties possess
the sa