The Wichita daily eagle. [volume] (Wichita, Kan.) 1890-1906, 1895-08-09
THE USE or DUST.
sh Important Factor In the Sum OF hT'
man Comfort.

| The USE Or OOSIs
.h Important Factor In the Sum Of l.v,
| man Comfort.
Those who have not investigated
the matter are apt to be surprised
when they are told that dust is a very
important factor in our comfortable
existence. So useful is it, indeed, that
we could not very well do without It,
and this thought should console those
who complain about the dustiness OF
the streets and highways in summer.
In the first place, we owe the beau
tiful blue of the armament to dust.
Were it not for its existence, the
heaven would be blacker than we see
/. on nights when the moon is hid be-
hind cloud. The glowing sun would
during the day shine sharply on this
black background, and the surface OF
the earth would be characterized by
the same sharp contrast of intense
light and deep shadow. The moon and
stars would be visible by day, and they
alone would not suffice 20 subdue the
sharp contrast.
When we look at the moon through
the telescope we ascertain how the
earth would look were there no dust,
for there is no atmosphere about the
moon, and consequently no dust is sus-
pended in the air.
! Our soft, uniformly diffused day.
light. for which our eyes are specially
adapted, is due to the dust, and the
beauty of the landscape. as can readily
be understood, is also due in no small
part to the same despised article.
While it has been explained how tho
| dust makes the whole vault of heaven
light, we have not told why it is chiefly
the blue rays of the sunlight that are
reflected, and the green, yellow and
req are at the same time only to a
small extent. The size of the dust
particles has much to do with this mat
ter. The air currents only bear the
| finest particles to every stratum, and
these fine particles which are of chief
interest in this connection.
The ether waves which constitute
the essence of the mechanism of light
are microscopically small, although
they vary in their smailness. Many Of
the fine particles of dust are large
enough to reflect the extremely short
blue ether waves, but fewer are
capable of rejecting the yell
low and green waves, while
still fewer are large enough to
influence the long, red, ethereal
waves. Consequently, the long red
waves pass through the greater ma
jority of the dust particles without be-
ing reflected. while the shorter blue
waves are intercepted and diffused at
every point, and hence become visible.
1t is for this reason that not only the
finest dust, but the heavens them
selves appear blue to our eyes
This blue sky is most often found in
the country. and city residents will
naturally seek to know why it is that
the sky in their vicinity has a whitish
or grayish appearance. This is be-
cause the particles have united, and
are able to reflect the light in it's en-
tirety. When there are a large num-
Der of large, coarse dust particles in
the air, as is the case in the city, the
sky has whitish tinge. The sky is
bluest on the mountainous, because
there the air is SO rariied as to sup
port only the finest dust particles.
The sky would be almost black at a
great height if there were no dust
particles in supervision. As we turn
our eyes to the lower strata of the air
stewards the horizon. we see it grow
pale.
The blue skies of Italy and the trop-
les are famous to all travellers or read
ers of books of travel. Why is it that
the skies there are bluer? Are the
dust particles finer? The answer is,
Yes" Not that the dust that rises
there is finer, but that in our climate
the dust is soon saturated with water
vapor. which makes them coarser.
The vapor retains its watery charac.
ter, and does not condense on the float
ing dust. 1t is not condensed into
clouds until it reaches much more
lofty, and hence colder regions.
To dust, then, we owe our fogs,
clouds, rain, snow. delightful sunsets
and the cernlean sky. Did it not exist,
the only objects upon which the vapor
could condense would be the face of
the earth itself. with the men, ami.
mails, houses and trees upon it All of
these would begin to drip with water
whenever the air was sufficiently cool.
In winter everything would be covered
with a crust of ice. Umbrellas would
not prevent US from being constantly
wet, for our clothes would become
saturated with the water condensed
from the vapor which had fallen upon
us.
Were we to fly indoors we could not
escape it, as the vapor-laden atmos.
,phere would follow us, and condepse
upon the walls Of our rooms and the
furniture of our houses.
We're there no dust, our world, in
short. would be a very different one.
! 1t is only recently that scientists
have begun to appreciate the important
part played by the much despised dust
in the economy of nature. This grow
ing interest in it has led them to take
measures to count the numbers of par.
ticles in given space.
At the surface in London and Pari.
it has been found that a cubic cent?.
meter, or a little less than six hun.
dredths of cubic inch. contains near,
ly a'quarter of a million of particles o!
dust. On the top OF the Alps. how.
ever, the number to cub centimeter
decreases to two hundred PARTICLES
Golden Days.