The times. [volume] (Washington [D.C.]) 1897-1901, 1901-01-21
A Study OF The CLOUDS
New Facts Discovered by the In
terna;ional Survey.
Altitude of the Various Kinds of
.aporOus Formatiops-1hc Highest
of Them From Three and IA Half TO
Four Miles Above the Enrth-Area
Affected by storms.

Prof. Frank H Bigelow, meteorologist
and astronomer of the National Weather
Bureau. who directed the American branch
CT the survey. In this country fifteen sta
tions carried on the work. The observers
were required among other things to
measure the height and velocity Of clouds
The highest of all clouds were discovered
TO be those delicate, white, fbrous de-
tached masses Of frozen vapor seen high
against the blue sky. Sometimes they ar
range themselves in belts crossing the
heavens. Often they appear to be groups
of motioniess islands. far up in the blue,
atmospheric sea. The topmost point of the
highest of these measured was ten miles
above the earth. These highest clouds
named cirrus-were found to conine them
selves to an atmospheric stratum or belt
extending from the ten-mile height 10
within three and a half miles OF our
heads
The second highest clouds were dlscov-
cred TO be those appearing as thin, whitish
sheets. at times completely covering tine
sky. Covering the sun or moon, they pro-
duce halos thereabout These, the GIRO
stratus, are found to be companions of the
cirrus of medium height. Their belt. FIVE
and half miles deep, is included between
points, nine and one-third and three and
three quarters miles up.
The third highest clouds were found to
be those forming the rackerel sky. These
named GIRO cumulus. are globular masses
white fakes or whisps, without shadows
and arranged in groups or rows. Their
belt extends from point eight miles above
our heads 10 within two miles of the earth
and is consequently six miles deep
Fourth in the order of height are the
alto stratus-thick bluish-grey Sheets
often showing a brilliant patch in the
neighborhood of the sun or moon In
warm weather their belt-six miles deep
begins eight miles up and ends trine
over mile above US.
Then come those large white or greyish
and partially shaded masses often so
closely packed together that their edges
are confused. Sometimes they appear like
ragged wall built of rough stone grow
ing gradually smaller and smaller toward
the bottom. These are the alto cumulus
clouds. The roof of their belt is about
six and a quarter miles; its bottom one
mile above the earth.
The long, overlapping rolls of dark
strato-cumulus clouds frequently cover
ing the whole sky, especially about the
present season Of the year. are sixth in
height. They show patches of blue sky
between them, and although dark do not
need ascend only two-thirds of a mile.
whence it would travel three and one
third miles to the top. which is four miles
above the earth
The wool-pack or cumulus clouds we're
found to be seventh in height These are
domeshaped on their upper surface, but
fiat al their base. When opposite the sun
than their margins. 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 measurement or
their belt showed that its upper limit is
two and a half miles, its lower q third of
a mile up in the sky.
The lowest of ali cloud forms was dis
covered to be the stratus, horizontal
sheets of lifted fog seen on damp days or
in very damp localities. Their belt, the
sha1lowest of all. is at the most only
mile and a half deep. II clears the earth
by a few hundred feet. Thus 1t is seen
that the belts. strata or layers occupied
by these eight species OF clouds overlap.
Thunder heads. occupying special class.
were found to raise their snow-capped
submits sometimes to eight and two
thirds miles, while their great fiat bases
sometimes venture within a mile Of earth.
Thus their belt is nearly eight miles deep
in the height Of their season. Some OF
these mountains of the sky measured in
July seven and one-half miles from base
to summit, and so were higher than the
tallest of the Himalayas.
They are undoubtedly snow-capped.
Prof. Bigelow in midsummer found the
temperature of one such summit TO be rs
degrees below zero, Centigrade-wbich is
as cold as the ground temperature OF the
polar regions in midwinter
Were We 10 ascend in a balloon and
]a,Iy=
rom base TO summit, We would travel first
through layer Of dry air and vapor; then
through another Of dry air. yapor and
water; a third of freezing vapOr. water
and ice. and finally, through the summit,
composed Of dry air, vapor, and ice, but
20 water.
The fastest of the thousands Of clouds
whose speeds we're measured. vas darling
through the upper air at the enormous
relocity of 19S miles an hour This was a
drro-cunulus cloud-one Of the mackerel
Ky class. observed in December. The
slowest cloud observed was of the cumu-
lus or wooI-pack category. II was moving
at about nine hundredths Of mile an
hour.
The average yelocities Of the different
classes varied very nearly according to
their average heights.
The first accurate knowledge as to the
velocity o. the wind at various heights
was thus obtained from the clouds The
atmosphere was found to consist of lay
ers. each Of which is moving more swiftly
than that next below II.
One important discovery by Prof Bige-
low is that clouds not only travel faster
in cool than in warm weather. but that
their velocity is greater in regions of low
than in those OF high atmospheric pres
sure.
The direction Of the rapidly rushing
torrent Of air in the region Of the high
est clouds is found al each station TO b.
due eastward across the United States
and foreign statistics indicate that it con
tinues thus around the entire world. I
caught in this upper current an airshil
or balloon would continue 10 circumnavi
gate the world. The ashes from Krakatoa
the volcano, continue around the eartl
for several years, and produced wonder
full sunset effects.
AS the earth's surface Is approached
Prof. Blgelow finds, the air currents be
come more and more serpentine. A mill
and half UP eddies begin to form. Still
lower and against the earth's surface
these eddies form great storm vortice.
1900 to 1000 miles in diameter.
The cloud survey. according to Prof
Bigeiow, Proves that storms are forme,
only in the thin skin Of air nearest tn,
ground. The high. white clouds know NJ
storms When the wind is changing I,
blow up weather disturbances below thi
eastward drift Of atmosphere carrying
these clouds continues undisturbed. Til,
most rapid storm motions are in TIT
clouds one and one-half miles up. Abov
and below this height The storm motion
decrease