The midland journal. (Rising Sun, Md.) 1885-1947, 1903-05-22
POINTS ABOUT PIGMENTS.
What 1t Is That ColOrs the Leaves
md Flowers and Everything
in Nature.

and Flowers and Everything
In Nature.
A pigment is substance which i'm
parts color to an object, as does
paint. White light is made up of
waves of different lengths, which,
when falling upon our eyes, gives us
the sensations of red, blue, green and
so forth, according to the length of
the waves. When all the different
waves reach our eyes together, then
we see white. A pigment absorbs or
stops some of these waves of light
and reflects others. Thus if it is a
red pigment, it absorbs blue, yellow,
green and violet and reflects red. If
it is yellow pigment, it reflects yell
low only. All bright colors are not
due to pigments; for instance, there
is no pigment in the rainbow. The
colors of the rainbow are due to the
fact that waves of sunlight are re-
fected from the round raindrops at
different angles, according to their
length, and SO the white light is split
up into the different colors of which
it is composed. The same is true of
a glass prism, says the New Mexico
Bulletin.
The colors of flowers and leaves are
due to pigments; SO also the colors
of most birds and butterflies, though
sometimes feathers and butterfly
scales are so constructed as to reflect
the light at different angles in the
manner of a prism. These prismatic
effects in birds and butterflies may
be known from those due to pig
ments by the fact that the colors
change according to the angle at
which the objects are viewed, One
of the commonest kinds of flower
pigments is that which Is either pink
or blue and is called anthocyan,
which Is to say flower blue This sort
of pigment is seen in many wild and
garden flowers, and also in some
leaves, as those of the cultivated
.coleus. 1t is pink when the sap is
acid, blue when it is not acid or al
kaline. In some flowers, such as the
forget-me-not, the sap of the buds is
acid, and they are accordingly pink,
but later it loses it's acidity, and they
become blue. If you take some blue
flower and soak it in dilute acid, it
will shortly become pink.
Another group of pigments varies
from scarlet through orange to yell
low. These are such as color the rays
of sunhowers and the red and yellow
autumn leaves. The yellow form
which colors leaves is called Xantho-
phyll, which means leaf yellow.
The green color of leaves is due to
still another pigment, called chloro-
phyll or leaf green. This substance
is of great Importance to the plant
for other reasons than that of its
color.
White pigment are sometimes
found In butterflies, but white flow
ers do not owe their whiteness to
pigment. Flowers are made up of
innumerable little cells, and in white
flowers these are filled with air. The
little particles of air reflect all the
light, and so the flowers appear
white. You can prove this by viol-
emily squeezing or crushing the
petals of white flower, when they
will become translucent. The same
is true to Snow, which Is white be-
cause of the innumerable particles of
air entangled between the ice crys-
tails. If snow is crushed or beaten
down, it loses its dazzling brightness
entirely.
If you have no snow, you can see
the same thing in piece of cube SUI
gar. 1t is very white, but drop it
into your tea and it at once loses its
pure whiteness, while little bubbles
of air rise to the surface of the tea.
A very important animal pigment
is haemoglobin; this is found in our
blood corpuscles, and gives the blood
its beautiful scarlet color. In small
quantities it looks straw yellow, so
that red blood corpuscles seen under
the microscope do not look red at
all. The haemoglobin, like the an
thocyans, has two different phases
When it contains oxygen absorbed
from the air in the lungs it is bright
scarlet; but as the blood travels
round the body this oxygen it set
free, and the haemoglobin thus be-
comes reddish purple, as it is in our
veins. You can see the blush or pur-
pie veins at your wrist, and you
know very well the color of scarlet
blood as it flows from a wound.