Belmont chronicle. [volume] (St. Clairsville, Ohio) 1855-1973, 1888-04-05
Up IN THE CLOUDS.

! \ cloud IS a mass of visible vapOr or
water particles held in suspension in the
atmosphere. If it rests upon the surface
of the earth we call it fog. We see a
mass of vapor on the summit of noun
tain, we call it cloud; but if We climb
to the top of the mountain and find our
selves in the cloud we see it to be SIM
ply fog.
To our observation, clouds take forms
that are almost infinite in variety, Vet
they may be divided into six classes,
each presenting quite distinct character
istics. These are known as cirrus, Gu
mulus, and stratus cloud as simple di-
visions; and cirro-cumulus. cirro-stratus,
and cumulo- stratus as compound divis-
ions.
The cirrus cloud consists of long, slen-
der filaments. either parallel or diverg-
ing from each other. These clouds have
the greatest elevation and the least den
Sity of all clouds. Even in fair weather
the sky is seldom free from small distant
groups of cirrus clouds. They are thought
to be made up of spicula of ice or flakes
of snow, since at the great height at
which they float-from five to eight
miles above the earth-the temperature
of the air is below freezing point even
in midsummer.
The cumulus cloud is much denser
than the cirrus, and is formed nearer
the earth. 1t usually has the form of a
hemispherical or convex mass with hOr-
izontal base. This is the cloud often
seen in large masses near the horizon,
looking like huge mountains of snow.
The rounded top Of this cloud results
from the mode of its formation. As
the earth is heated by the suns rays,
currents of warm air arise, carrying with
them invisible vapOr. When they reach
a certain height, this vapor is condensed
and forms cloud, and since the upward
motion is greater under the center of the
cloud, the vapor is there carried to its
greatest height.
The stratus cloud is widely extended
horizontal sheet, often covering the en-
tire sky, and so low that it freqently
touches the earth's surface in the shape
of fog.
As for-the compound notifications of
cloud forms, the cirrO-cumulus is seen
in small rounded masses, often very near
together. On account of their feecy
appearance these are often called "woOly
clouds" This cloud is very frequent in
summer, but seldom precedes rain.
The cirro-stratus consists of fibrous
clouds spread out in strata, which are
either horizontal or slightly inclined to
the horizon. Sometimes the whole sky
is mottled with this cloud, looking like
the back of mackerel, and, therefore,
it is called mackerel sky. This cloud
always presages wind and rain.
The cumulo-stratus is the large dark
cloud formed by the massing of the fleecy
cumulus in great heaps. These clouds
are to be seen in great magnificence on
the approach of a thunderstorm, and
are, therefore, often called thunder
heads" Some meteorolOgistS also class
ify with the above the nimbuS cloud,
from which rain is falling, but others do
not think it worth while to keep this
division.
The height of cloud is measured by
trigonometrical rule by observing its di-
rection simultaneously at two stations.
In mountainous countries it can bet
compared with the peaks near which it
passes. Most accurate results are, how
ever, obtained by ascending in balloon
and noting the height of the barometer
when entering the cloud and again
when emerging from it, the barometer
giving the means of computing CORE
spending attitudes.
The height of clouds is variable. The
stratus, as we have said, often descends
to the earth. In pleasant weather the
lower limit of cumulus clouds varies
from 5000 to 5000 feet elevation, and
their upper limit from 5000 to $4,000
feet. Cirrus clouds never descend be-
low the summit of Mont Blanc, which
has height of 1874 feet, and are Of
ten seen to be far above mountains that
are 10000 feet high. 1t is estimated,
however, that they would not be visible
at a height exceeding ten miles. In
vertical thickness clouds are supposed to
seldom exceed half a mile, but the enor-
nous masses of cumulus are sometimes
estimated at over three miles.
Clouds move with the wind, and there
is no way of estimating their move
ment but by measuring the velocity of
the wind currents. Clouds reflect light,
of course, or they would not be visible;
such light as can pass through them is
refracted out of its path by the presence
of vapor particles. Thus, when we see
objects through fog we often notice
that they are distant from their true po-
sition or unnaturally magnified.
The effect of clouds on heat is to less
en- light, the water particles absorbing
it and lowering the temperature of the
air by their conversion into invisible va
por. Nevertheless, clouds hanging low
in cold weather prevent fall of temper
ature by preventing the radiation Of
heat from the earth's surface. As re-
CARDS moisture, clouds are, obviously,
moisture itself as well as the cause of
!