The Elk County advocate. [volume] (Ridgway, Pa.) 1868-1883, 1874-01-15
The Formation of Clouds.

Muhry has lately presented, in very
impressive manner, the conclusions de-
ducible from some observations pub
lished by Meissner, in 1868, on the for
nation of vapor vesicles and of clouds.
The researches of Meissner were mainly
directed to the relations of ozone and
antozone, and it was only as one of the
incidental results of his work that he
announced that, without the presence
of oxygen in the air, there could be no
clouds. In regard to this important
point Meissner's s researches have appar-
emily not attracted the attention that is
due them, and Muhry urges that me-
teorologists and physicists are not yet
to consider that the question of the ex-
istence of vesicles of vapor has been
settled in the negative. Basing his
conclusions on Meissners researches,
Muhry says that the condensation and
precipitation of aqueous vapor would
take place Immediately, in the form of
small drops, if it were not for the pres
ence of oxygen in the air that this gas
itself brings about the transition stage
the vapor vesicle. The experiments
of Meissner consisted in confning with
in the receiver of an air-pump mix
ture of aqueous vapor and the gas to be
experimental on. By a rapid stroke of
the piston the mixture is then quite
suddenly expanded, and the cooling
due to expansion produces a precipita-
ton of portion of the inclosed vapor.
The faint cloud that is seen by close OBJ
servation within the receiver continues
but few minutes, and was first OBJ
served with special care by Saussure.
in 1888. Meissner, however, has shown
that when other gases replace the air
within the receiver, the condensation
in general takes place not in the form
of cloud, but of fine light drops that
fall directly to the bottom, the cloud
being produced only when oxygen is
present, either pure or mixed with other
gases.
These experiments have been repeat
edly and very carefully made by Meiss-
ner with air, nitrogen, hydrogen, car
bonic acid gas, and in pure aqueous
vapor alone, and in various mixtures of
these gasses. Meissner further meas
ured the exact degree of expansion
needed to produce these vaper clouds,
and found that saturated air at 800
inches deposited it's vapor when the
pressure is suddenly reduced to ola
inches; by a second step he passed
from saturated air at ola inches to 16.
inches, when somewhat fainter cloud
was formed F; the third cloud was formed
on passing from 161 to 1875 inches, the
fourth on passing from 1873 to 1917,
and fifth on passing from 1917 to 8.5
inches. These barometria pressures
correspond respectively to attitudes
above the sea of about 5000, $4,000,
$4,000, $4,000, and 27,000 feet, and the
clouds successively formed were of di-
minishing grades of delicacy, those
formed in the rarest medium being ex-
tremely delicate and evanesoent. For
all further degrees of expansion Meiss-
ner was unable to perceive any cloud
vesicles, although minute transparent
drops were present. These results
would be directly applicable to our
atmosphere had Meissner been able to
reduce the temperature of his receiver
to that experienced in the upper re-
gions of the atmosphere.