Flora in all
her gorgeousness of coloring. The paleness of mountain and arctic
flowers, and the brilliancy of those of the tropics, point to the same
cause which gives the temperate zones their brightest flowers when heat
rays preponderate.

As depth of color seems connected with the red or heat rays; so perfume
belongs rightfully to the summer blossoms; when light is the strongest,
then we have our pinks, and roses, and lilies.

There are also in the spectrum four secondary colors: orange, green,
indigo, and violet. The secondary colors are alternate with the primary
in the spectrum, and are formed by a mixture of the two primary nearest
them--as orange, formed by a union of red and yellow; green, by a
mixture of yellow and blue; indigo and violet, of blue and red. Thus:

Red,

_Orange_,

Yellow,

_Green_,

Blue,

_Indigo_,

_Violet_.

Tertiary colors are many more than both primary and secondary. They are
hues not found in the spectrum. They are nature's stepchildren rather
than children, and many of them might not inappropriately be called
children of art; yet although most of them are of inventions that man
has sought out, they are at best but shades, and must all look back to
the spectrum as their common parent.

Each of the primary colors forms a simple contrast to the other two;
thus blue is contrasted by yellow and by red, either of which forms a
simple contrast to it; but as it is a law of color that compound
contrasts are more effective than simple in the proportion of two to
one, it follows that a mixture of either two of the primitive colors is
the most powerful contrast possible with the other.

Red and yellow form orange, the greatest and the most harmonious
contrast to blue; red and blue form violet or purple, so much admired in
contrast with yellow in the pansy; yellow and blue form green, the
contrast to red, and the color needed to restore the tone of the optic
nerve when strained or fatigued by undue attention to red. This is the
most common and admirable contrast in the vegetable kingdom; the
brilliant red blossom or fruit, with green leaves, as instance the fiery
tulip, the crimson rose, the scarlet verbena, the burning dahlia, the
cherry and apple trees, the tomato or loveapple of my childhood, and the
scarlet maple and sumach of our American October.

There are two distinct harmonies of color: the harmony of contrast, and
the harmony of shading. The former is the harmony of str