Nashville union and American. [volume] (Nashville, Tenn.) 1868-1875, 1871-05-05
COLOR OF THE Sky.

From an interesting paper in the PTac-
teal Farmer, contributed to that jour-
nal by Gen. A. J. Pleasonton, of Phila.,
on the influence of the blue color of thu
sky on the development of animal aud
vegetable life, we make the extracts be-
low. After referring to the intense~blue
of the tropical and equatorial sky, as men,
toned by Humboldt, and to the equally
intense blue of the circumpolar sky, as
observed by various arctic and antarctic
nayigstors, Gen. Pleasanton suggests the
hypothesis that this intense blue may be
owing to the escape from the earth of
positive electricity at the poles, as shown
in the auroral light, and to its return at
the equator, as shown in the zodiscsl
light. He then proceeds:
Il was announced in England about the
beginning of this century, that the red
ray of light was Nesting, the yellow ray
was illuminating, and the blue ray in a
remarkable degree stimulated the deVel-
opment of vegetable life.
From this discovery we can imagine
the immense influence which the intense
ly blue color of the sky in the equatorial
regions has, and always has had, in con-
junction with the sun's white light, and
the heat and moisture of these regions,
upon the DEVELOPMENT there of vegetable
life.
This intensely blue color of the sky in
the arctic regions may also serve to explain
the exuberance OF animal life there. II
being known that the deeper water of
| the arctic ocean is much warmer than the
surface water which is often frozen, fur.
nishes abundant food for its inhabitants.
The increased temperature of this deep
water is probably derived from radiation
of heat from the interior of the earth un.
der it-ss all those regions are more OF
less volcanic; witness Iceland, Jean May.
en-, Spitzbergen, etc. Thelaws of animal
and vegetable life being very analogous,
what would stimulate one would proba
bly, have a similar effect upon the other.
In the arctic waters you have warmth,
food, light and electricity, escaping
! through the waters into the air, and al
stimulating life.
Whoever has noticed the color of the
electric spark in atmospheric air, from al
electric machine, will readily recognize
its likeness of color to the blue color OF
the sky.
One of the most beautiful illustrations
of the mighty influence of the blue colo
of the sky upon vegetation, is TO be foun(
in the green color of the leaves of plants
1t is known that blue and yellow wheI
mixed produce green, which is darker
when the blue is in excess over the vel
low, and the reverse when the yellow
predominates. Now let US observe th
process of germination-Seeds are plantet
in the soil--at first white worm-lik
thread at the lower part of the seed az
pears; it is white, and contains all tn
primary rays of light; it is the root of tn
plant-and remaining under the soil cor
linues white. At the upper end of th
seed also appears white swelling, whic
continues to grow upward till it approach
es the surface of the soil, when chang
occurs in its color. This is the leaf
absorbs yellow from the soil which
brown Composed of yellow aud black,
and as soon as il comes within the infiu
ence of the blue sky, it absorts from
the blue light, which, mixing with th
|, yellow already absorbed, produces a ye
lowish-green, which finally assumes tn
deeper tiDge of green that is natural t
the plant. The plant blossoms, forms i
seeds and seed vessels, and hsyin
fulfilled its mission, the blue color of IL
green of the leaves is eliminated, Ii
leaves become yellow, and absorbing Il
carbon of the plant, they change the
color to brown-the sap vessels of Il
, leaves are choked by the carbon-th
leaves are dead and fail to the grounr
Thus the blue ray is the symbol of vita
: ty; the Yellow ray, that ofdecay and deaf