Evening star., 1909-09-05
WORLDS TWO ATMOSPHERES
LAYERS DIFFER IN THEIR
COMPOSITION.
THEIR
Strange Data Obtained by the En-
ployment of Sounding Balloons.
Neither Clouds Nor Storms.

From the Literary Digest.
That the upper part of our atmos-
phere differs so much from the lower
in composition and characteristics that
it may be practically regarded as a
separate layer floating on the lower,
much as a layer of oil floats on water.
is what we are told by writer in the
Revue Scientihque. This fact has been
discovered only recently, and by means
of data obtained with "sounding ball
looms" The higher or floating layer Of
our atmosphere is quite dry, almost
perfectly still and is Of almost he
same temperature throughout. 1t is the
still atmosphere, as opposed to the
tumultuous region of clouds and storms
just below 1t. Says the writer from
whose account we Translates:
When balloon ascension, or the as
cent of mountain. is made. ii is per-
ceived that the temperature falls as we
rise. Until recent years 1t was supposed
that this decrease. which takes place in
all countries and under the most different
conditions, continued up to the extreme
limits of the atmosphere. But data gath
cred by means of sounding balloons
have shown that this Interpretation does
not correspond with the reality. In all
latitudes the decrease of temperature
ceases at a height of between seven and
one-haf and nine and one-half miles.
AT higher points the temperature of the
air either remains stationary, or else,
is often the case, it increases slightly
with the height.
Three Distinct Regions.
1T is shown by Mr.. w. ]. Humphrey
- that the part of the atmosphere
hitherto explored may be divided into
three more or less distinct regions
THE first extends to height of about
10000 feet and is the lowest and densest.
Its winds are irregular. and the direction
is determined chiefly by the relative po-
sitions of centers of high and low pres
sure. The temperature decreases quite
lrregularly, and diversions often present
themselves. 1t is in this layer partic-
ularly that rain clouds or snow clouds
occur.
I'm the second region. between 10000
ana 3O,0OO feet, the decrease of temper
ature becomes much more regular; it
is sensibly controlled by the laws of adj
aDatlc expansion labout i degrees +. to
100 feet).
The centers of high and low pressures
still exert. In this region, great influence
on the direction of the winds: neverthe-
less, as we rise. this influence lessons; in
the end the movements Of the atmosphere
according to the laws of the general cir
cuiatlon. prevail, while the velocity of the
currents grows greater and greater In
TINS region neither cOndenSa ton nor pre-
cipitation takes place. The nimbus clouds
are below 1t. in fact, and the cirrus float
in its upper part. This zone is sometimes
the seat of vertical convection currents
whose extent and intensity are variable;
but generally. as shown by the absence of
clouds and the regular decrease of th,,
temperature, 1t Is most stable
Layer of Inversion.
The third region is that above the
limit. The Temperature, in
stead of decreasing. rises with the height.
and some authors call the region, on this
account the layer of inversion In this
part of the atmosphere the air would ap-
pear to be excessively dry and the veloc-
ity of the wind much less than in the
subjacent layer: vertical convection cur
rents cannot exist because the tempera-
ture increases with the altitude 1t is now
proved that the height at which this
zone is found depends on the season, the
latitude and the barometric pressure 1t
is greater in summer than in winter and
at the equator than In our part of the
world 1t Is weaker above centers of low
pressure than above high The higher
this inversion layer the lower is it's tenn
perature. all other things being equal.
ITO sum up. the earth may be regarded
as surrounded by two distinct and super
posed atmospheres that mingle only very
SnSnIly. Hc lOWtT Is lHdI Ill which are
produced the disturbances that cause
weather changes: the temperature there
falls rapidly the altitude increases; it
nearly tWo-thirds. perhaps even
of the total mass of oxy-
gen and nitrogen, still larger proportion
of the carbonic gas and almost all the
water vapor. The higher layer floats on
the lower somewhat as oil floats on
water, its temperature rises with the al
titude. quite rapidly at first and then
much more slowly. Sometimes, even the
temperature within 1T varies so little that
1t may be considered as constant: whence
the name of isothermal layer given to if
by its discoverer. Mr.. Teisserenc de Bort