The Iowa plain dealer. [volume] (New Oregon, Howard County, Iowa) 1867-1895, 1888-05-10
RAIN CLOUDS.


densation-IIow Water 1. Drawn Into
the Air and WHY IL Dcscenels.
Did YOU ever stop 10 think, when
you looked out of the window and saw
dull. gray c'ouds from which the rain
was so steadily pouring, and which
seemed 10 shut in the world all
around. that. in reality, they extend
cd over a very small part Of the coun-
Try; that somewhere else, perhaps
only twenty or thirty or hundred
miles away. the sun was shining. and
all was bright and beautiful? This is
really the case. For storms. however
long and drcary. do not extend over
many miles; and though it always is
raining ut some place in the world.
yet always and at the same time it is
pleasant somewhere else. Now. let
us see why this is.
Suppose that on warm summer
afternoon we were to bring n pitcher
Of clear. col water, fresh from the
well. and to place it on the table in
the dining-room. Now, no matter
how carefully we may have dried the
pitcher before bringing it in. we shall
discover if we watch closely. that the
outside soon becomes wet or misty;
and that the mist grows heavier and
gathers into drops and perhaps even
runs down the pitcher TO the table.
Now. where does this water come
from? Mt through the sides of the
pitcher, that is impossible; but from
the mir. We can not see ii. perhaps.
but still it is there in the state Of vapor
How came it there? Did you ever
notice. after rain, how in 4 short
time the puddles became dry. and how
the moisture disappeared from the
cras, and leaves rs soon rs the sun
shonc ont and the wind blew? Or.
did you ever noice that if you left a
pan Of water out-of-doors the water
each day grew less and less, until all
was gone and the pan dry?
All the water that was in the pud-
dies, on the grass and leaves Except
that which soaked into the ground)
and in the pan. was taken up as vapor
into the air-has ''eyaporatcd." rs we
say. The same thing happens when
water boils. only it then evapora' cs
more rapidly. and we can see the
vapor arising as steam. II you live
near a river. or in country where
thcr, are brooks. perhaps you can see
this evaporation actually taking place.
Get up early some morning. before the
,.scn- Lob ,,,A Il L..
river. You may sec long line of mis-,
or fog. like big white cloud, hanging
over the water. Now. this mist is only
the water cvaporating from the river
aud is just now visible Us fog because
the air is cool. And the sun has
shone, the air becomes warmed and
the fog disappears. but the cv aporation
goes on. nevertheless deed. it is
going on continually, and all over the
earth; so that if the water were not
returned to us as rain, snow and dew.
all the oceans. lakes and rivers would
III time dry up and disappear All the
trees. grass and plants would then
wiihcr. and our beautiful land would
become as dry and parched rs the
great desert Sahara.
Having learned how the water il
drawn into the air. let us see how and
Why it comes down again rs rain OF
snow or dew.
There is singular thing about thi,
moisture, which is this: tho air will
hold only certain quantity of it. and
that quantity depends upon the tenn.
perature of the air. But warm air al
ways holds more than cold; SO. how.
ever warm the air may be. or how
ever / much moisture it may con.
tain rs invisible yapor. we have only
to cool it enough and the vapor con
denscs. rs we say; that is. it becomes
visible. first rs fog or mist. and thcr
rs drops Of water. such rs we sec OF
the pitcher. And the reason we see
white fog rising ut night. after thu
sun goes down, is only because til.
water. which has been evaporating al
day and going up into the air rs in
visible vapor. becomes condensed t
fog by the cooling of the air when the
suns heat is withdrawn. When thu
sun rises. the fog disappears; but tn.
yapor still asccnds. and when it rcaclle.
the altitude where the air is always
cool. it becomes condensed again a.
fog. only it is then called ''clouds. '
| And if it becomes condensed enough
10 form in drops of water, they fall,
and 1t rains orsperhaps. it SHOWS
for snow is but froz,n rain. George
T. Merrill. in ST. Nicholas.