The Irish standard. [volume] (Minneapolis, Minn. ;) 1886-1920, 1890-08-30


TIE s is Is BLu 81
vsriety 81 pronslneat laeax.sniy 1,nts
Clever 81 Y - Ne 4 .s9ls
You have al noticed, & said an 81
L tro11omer to- j >Cincinna ii .Times-Star
man, IS d when we look away frc: the
sun int the cloudless sky the heavens
appear blue; when, however. we look u. tn
the direction Of the sun. espec ially
when, after sunset, We look toward the
western horizon, the color il 8 low
/ fish red With the spectroscope Il can
be shown that the white light from the
sun is produced BIZ 9 mingling OF differ
emit colored rays. Indeed this can be
shown by means Of any triangular
prism, say one Of the pendants Of IS
chandelier. One Of these placed II the
path of a beam Of light will project ont
screen band Of seven colors red
orange, yellow, green, light blue. dark
blue and violet. Understanding this,
we can readily see how the effect3i is blue.
when piece OF blue glass is interposed.
or red when red CLASH used All but
the blue and red rays respectively are
absorbed; these, however. pass through
freely, and we say that the body Is
blue, or red, when really the color
is not property Of the glass in any true
sense, but Of the sunlight What has
this to do with the sky colors? will
now show you. Dissolve q little white
CASTLE soap in tumbler Of water, so as
to make the slightly turbid. Place
black screen behind the tumbler and
hold the whole so that the sunlight
must be reflected from the liquid before
it can reach your eye. The liquid will
appear blue. Hold it next in a direct
line toward the sun and it appears vel
lowish red. Now these are the exactap-
pearances of the sky Sky light is re-
fracted light. The water PARTICLES in
the atmosphere, like the PARTICLES OF
soap In the water, retract blue light;
while the background of darkness sur
rounding the earth replaced the black
screen. The atmosphere, like the solu-
ton Of soap and water. transmits yell
low and red rays but slightly refracted.
refracted too low to be seen; hence when
we look toward the source of light in
the evening or morning the sky Is OF a
yellowish red color This effect is more
pronounced then than during the day,
because when the sun is near the hori-
ION the rays travel a greater distance in
the air in order to reach the earth than
when directly above u.s. Consequently
the blue rays are more. thoroughly
refracted.
1.-THE atmosphere has many effects In
modifying the appearance OF the sky /
and the heavenly bodies. Look at Venus
over there near the western horizon and
Just below the crescent moon, which has
come into plain view while we have
been talking ION account Of the deepen.
ing darkness). Its real distance from
the horizon is not as great as it appears,
for the rays OF light which it reflects to
IA, and which it receives from the sun,
are bent downward when they pass into
our air, perhaps fifty miles from the
earth's surface.
''As the effect Is the same as that
which would be produced were there no
atmosphere, by rays proceeding from
higher star, we locate the body in 2
more elevated position than the one
which II. actually ooeuptes. Put dime
on the bottom OF pail flied with water
and you have like conditions with SINH
lar effect. II You place your hand
where you think you see tho coin you
will not touch 1t, but.s spot perhaps an
inch above the true bottom. Again, do
You notice how steadily Venus shines?
II you are here in an hour later, when
the stars are all out, you will observe
that all those near the horizon,
the others to a smaller extent,
are merrily twinkling. This ap-
pearance, made familiar to all OF us by
theold nursery rhyme: Twinkle, twinkle,
little star is not noticeable in the
case Of any. planet except Mercury, and
has been subject of much study on the
part of scientific men; it rs now gener-
ally believed that It arises from the UNI
equal bending of the rays of light as they
pass through aerial currents of different
temperatures and densities. The facts
seem to support this theory, for where
the air is the densest-near the horizon
the effect is moss noticeable, where it
is the rarest--in our zenith-it is less
marked.
'sThis twinkling produces another IL
fusion. When we look at the heavens
on clear winters night the first inn
preston on our mind is that we see an
almost infinite number OF stars. In
truth, seldom can an ordinary eye dis
Germ more than 1000 at once; If you
should observe the sky nightly for q
whole year there would be presented to
your view only about 5000. But il you
take telescope, as Sir VIM. Herschell
did, and point it toward that portion OF
the milky way which looks the wh1test
and the 1nilkiest, you will see more
than GOO, 600 stars pass across the field of
your instrument every fifteen minutes"
Feathored Military Messengers.
The popular name of ''swifts'' is like
" to be more than ever appropriate If
the following announcements is verified:
.sThe training Of swallows for military
purposes is being proceeded with active
" at Roubaix. under the observation OF
Captain Degouy, who has been detached