Martinsburg herald. [volume] (Martinsburg, W. Va.) 1881-1920, 1901-02-09
STUDYING THE CLOUDS.
Interesting Results Obtained by
international Survey.
HIGHEST ARE TEN NILES Up.

ferent Layers Dcscribed--Tshe Low
est Come within n Few Hundred
Feet of the Emrth--Their Velocity
as High as Three Miles a Minute.
The work OF the international cloud
survey Is ended, and some OF the re-
suits are made public in volume pre-
pared by Professor Frank III. Bigelow,
meteorological and astronomer of the
national weather bureau, who directed
the American branch OF the survey.
In this country Is stations carried on
the work. The observers were rcquir-
ed among other things to measure the
height and velocity OF clouds.
The highest of all clouds were discov-
cred to be those delicate. white. fihrous,
detached masses of frozen yapor seen
high against the blue sky. Sometimes
they arrange themselves in belts cross
Ing the heavens. often they appear to
be groups of motionless islands far up
In the blue. atmospheric sea- The top
most point 81 the highest OF these
measured was ten miles above the
earth. These highest clouds named
cirrus were found to confine them
selves 20 an atmospheric stratum or
belt extending from the ten mile height
to within 81 miles OF our heads.
The second highest clouds were dis
covered 20 be those appearing as thin,
whitish sheets, at times completely
covering the sky. Covering the sun or
moon. they produce halos thereabout.
These, the GIRO stratus, are found TO
be companions of the cirrus of medium
height, Their belt, 5i6 miles deep, Is
included between points . 1-3 and 3h
miles up.
The third highest clouds were found
to be those forming the mackerel sky.
These, named GIRO cumulus, are globu-
lar masses, white fakes or whisps,
without shadows and arranged In
groups or rows. Their belt extends
from a point eight miles above our
heads to within two miles of the earth
and is consequently six miles deep.
Fourth in order OF height are the
alto stratus--thick. blush gray sheets.
often showing a brilliant patch In the
neighbornood OF the sun or moon. In
warm weather their belt. six miles
deep. begins eight niles up and ends
tri1e over mile above us.
Then come those large. white or
grayish and partially shaded masses
often so closely packed together that
their edges are confused. Sometimes
they appear like a ragged wall built
of rough stone, growing gradually
smaller and smaller toward the bot
tom. These are the alto eumulus
clouds The roof OF their belt Is about
6A miles. its bottom one mile above
the earth.
The long. overlapping rolls Of dark
strato cumulus clouds, frequently COW
ering the whole sky. especially about
the present season of the year. are
sixth in height. They show patches
of blue sky between them and. al
though dark. do not bring rain. TO
reach their belt balloon need ascend
only two-thirds of mile. whence it
would travel three and one-third miles
to the top. which is four miles above
the earth.
The woolpack or cumulus clouds
were found to be seventh in height.
These are dome shaped on their upper
surface. but fiat at their base. When
opposite the sun. their sides nearest
the sun are brighter than their mar
gins. When the sunlight falls upon
them aslant, they show deep shadows.
When on the same side of the sky as
the sun. they appear dark. with sill
very Innings. The careful measure
ment of their belt showed that its up
per limit is 21a miles, its lower third
of a mile up in the sky.
The lowest of all cloud forms was
discovered TO be the stratus. horizontal
sheets of lifted fog seen ON damp days
or in very damp localities. Their belt.
the shallowest of all. is at the most
only ~ miles deep. 1t clears the earth
by few hundred feet. Thus it is
seen that the belts, strata or layers oc-
cupied by these eight species of clouds
overlap.
Thunder heads, occupying a special
class, were found to raise their snow
capped SUBMITS sometimes to 2-3
miles, while their great fat bases
sometimes venture within "a mile of
earth. Thus their belt is nearly eight
miles deep in the height of their sea-
son.
The fastest of the thousands OF
clouds whose speeds were measured
was darling through the supper air at
the enormous velocity of 1913 miles an
hour. This was GIRO cumulus cloud.
one Of the mackerel sky class observed
in December. The slowest cloud OBJ
served was of the cumulus or woolpack
category. 1t was moving at about
nine-hundredths OF a mile an hour.
The first accurate knowledge as to the
velocity Of the wind at various heights
was thus obtained from the clouds.
The atmosphere was found to consist
of layers. each Of which Is moving
more swiftly than that next below 1t.
One important discovery by Profess
or Bigelow Is that clouds not only
travel faster In cool than warm wealth
er, but that their velocity is greater in
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