The Mitchell capital. (Mitchell, Dakota [S.D.]) 1879-1918, 1903-12-04
REASONS WHY SKY
IS OF AZURE TINT
Different Scientists Have Ad-
vanced Different Reasons
to Explain 1t.
EXPERIMENTS
"Sky Blue" Produced in Laboratory
Experiments-Color Caused by
Reflection of Sunlight From
Particles in Air.

Scientific American: Every n 10
tees the blue color of the sky. ]
has grown familiar to US by daily OBJ.
%servation from childhood, yet few per-
sons realize the great scientific and ar
tistic interest attaching to this beau
tiful color.
Sir Isaac Newton tried to explain the
color in the year 1875 by referring 1t to
the blue colors seen in thin soap bub-
bles used in his experiments. He
filled with small particles Of water,
which reflect the blue portion of the
suns light falling upon our earth, n
thus produce the blue tints of the fir
mament
Sir John Herschel explained the col
or of the sky by Newton's theory, but
later writer's have proved that in some
important respects his theory was
wrong.
In 1869 Professor John Tyndall, the
famous British physicist, found that he
could produce SKY blue" by expert
ments in the laboratory.
For his purpose he filled a glass
tube about a yard long and three inches
in diameter with air of one-tenth the
ordinary density mixed with nitrate of
butyle vapor, which is extremely vola-
tile. Then on passing through the
mixture a powerful beam Of electric
light in a room otherwise dark the
mixture precipitated a beautiful blue
cloud, which in color rivaled the fines
Italian sky. Further experiments
proved to Tyndall that he had at last
discovered the secret Of the blue color
of the sky, which has puzzled the
greatest philosophers Of all ages.
Lord Rayleigh, the famous professor
of experimental physics at Cambridge,
Eng, and one of King Edwards orig
ino tua1ya nonrnharc nf fha nav 0r1ar
Of Merit, has investigated Tyndalls
theory Of the color of the sky by pro-
found mathematical researches extend
Ing over many years. He confirms
Tyndalrs theory h a the blue arises
from small particles in the air less
than one hundred t~housandth of an
inch in diameter. Billions n tril-
lions Of these atomic particles fill the
atmosphere, and by rejecting the blue
part of the sun light give the dome
of the heavens a blush tint.
What the Particles Are.
Some Of the particles are water, but
most Of them are composed of the oXy-
gen and nitrogen which we breathe.
Professor T. J. j.. See of the United
States navy is one of the American
scientists who have studied the subject
in another aspect. He has observed the
color of the sky in various attitudes in
high mountains and in dry and moist
countries, such as Egypt and Greece
and Arizona and the Mississippi val
ley. His conclusion is that the beauti-
full red colors Of sunsets and sunrises
SO much Spoken Of by Greek n Rom
an writer's and so often illustrated in
landscape painting arise from water
vapor in the lower layers Of u atmos-
phere, absorbing the blue and trans
hitting the red light. According to DR..
See the reddish colors come from that
part of our air within five miles of the
,yLs1@ +1o l~o- 11,o 80
the sky arises from reflections Of mi
mute particles in the higher parts Of our
atmosphere. The water vapor does not
extend very high, clouds never rising
higher than ten miles above the earth.
The blue streaks cast by clouds at sun
set show that the red arises near the
earth, while the Glue has it's seat very
high up. Above our atmosphere the sky
! has all the blackness Of the darkest
night.
Professor See has watched the dura-
ton of the blue sky after dark and
found it to continue for about an hour
and fifteen minutes, and from this he
shows that our atmosphere extends to
a height Of fully 100 miles. Astronom-
ers have usually found the height Of
the atmosphere by computing the
height Of meteors, but none ever made
the height of the atmosphere over 100
miles.
The study of the blue color of the sky
thus proves also that our atmosphere
extends considerably higher han
scientists have heretofore supposed.
On our dark days the blue color Of the
sky is shut out by clouds, and combi-
nations of colors due to rejecting clouds
and countless myriads Of particles in
the ethereal regions high above the earth
give the bright light which is SO much
relished in daily life. The nature of
the blue sky SO much admired by all
-sA-- H. 1--v~ %
Job, now fully explained by modern
science, still preserves it's ancient
beauty and will inspire mans mind
through coming ages.