Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1891-10-15

blue through this medium, and the
| unilluminated parts of the moon can
not be distinguished from the space
that abuts it. Bright, direct and re-
Elected light is not affected appreciably
by its passage through our atmosphere:
therefore, stars, moonlight and distant
Examinations are not noticeably blue
from that cause
1t may be well to examine sunlight
| to see why it is not made blue in tran
sit and as the moonlight is sunlight
reflected. the explanation will do for
both. and, in fact, for all. To a ter
restrial observer of the sun there is
visible an Illuminated cone. the apex
OF which is in the eye and the base on
the solar disk. Reducing this cone to
the dimensions that the mind can
grasp we will adopt a scale of 5000
600 miles to the inch and imagine or
construct cone ten feet high whose
base is one-half an inch in diameter.
Now if the mathematical point or
apex of this cone be blue, five ten
millionths OF one inch thick. which is
the proportion roughly. considering
the atmosphere to be forty miles high,
it will be seen why sunlight so easily
overcOmes the color of air. If
however, We construct a cone to
illustrate the view of earth to a
lunar observer. We must to a height
OF ten feet have base of two inches
diameter, with a blue coat on that
base one-sixteenth of an inch thick Ca
very thick card is about that thick
ness.) Here the base of the cone is
blue instead OF the fine point, and
every ray travels through the whole
thickness Of the atmosphere of earth
twice. The whole terrestrial disk
lowered by its blue envelope is seen at
once, and If, as we know to be true,
the air colors distant objects blue to
the observer On earth, it must color
earth blue to q lunar eye.
do not forget that when earth is
'full" to the moon there may be
white spot or spots where the direct
solar rays are reflected to the moon,
but that spot cannot equal the appar-
ent area of the solar disk, or rather
one-siXteenth part of the apparent
terrestrial disk
OF course, when the moon is eclips-
ed to earth, the effect to the lunar OBJ
server would be solar eclipse. Then
the blue air should be visible around
the edge of the earth slightly like that
seen about the moon in some cases of
total eclipse and known as the corona.
At such times the aurora should faint
1y-
earth and perhaps slightly be reflected
on the eclipsed satellite.
IF we consider aurora borealis and
Its data. comparing it and them to
netula and comets tails. we must be-
lieve that the earth has on the side OPP
posite the sun Il veritable streaming
appendage of bright luminous effect.
Authorities after differing infinitely in
results, now declare that they are ig-
norant Of the height to which this phe-
nomenon reaches. Humboldt saws ten
degrees, which means any height ac-
cording to distance. The same auro-
ra has been seen from polar localities
to II degrees north. No one knows
their height because our atmosphere
may shut out great part of distant
effects and moonlight and twilight
probably neutralize the higher effects
to all observers. The only question is
does the lunar observer see q tail
streaming after earth? And, consid-
ering the clearness that the tails of
comets exhibit 100, 900, 900 miles dis
tant and visible nebula unknown mil
lions of miles in space, I assert that
aurora borealis should be and is
bright and beautiful trail after our
great mothers glorious garments
There are many colored stars and
planets. Mars is red. Venus is white
Many stars are blue; in one group all
are blue