Atlanta tri-weekly journal. [volume] (Atlanta, Ga.) 1920-19??, 1923-02-15
Cornell Professor Describes
Experiments in AirpIane,
Fog DiSpeIIed in Five to Ten
Minutes Process Patented

DAYTON, O., Feb. 19.-(By the
Associated Press.) - Rainfall has
been caused and clouds have been
made to disappear in a series of eX
periments which are being conduct
here at McCook field. according to
announcement made today by the
experimenters, Prof. Wilder D. Ban
croft, of Cornell university, and L.
Francis Warren. The successful ex
periments were made with the CO.
operation of the army air service.
Results of the experiments were
described as absolutely uncanny'
by observers at the army air field
In brief, the clouds We're made to
disappear and precipitate their
moisture by the dropping of cleo
trically charged grains of sand upon
them from airplanes.
Prof Bancroft and Mr.. Warren
claim that the process will be of
great value in the commercial
world, as fogs over cities, harbors
and flying fields can be made to- dis
appear, thereby insuring safety to
travel and transportation. They do
not claim that in every instance rain
or precipitation can ben produced as
they say all clouds do not contain
sufficient moisture. Some of the ex-
periments demonstrated that while
slight precipitation was caused, this
Precipitation was eVaporated before
it reached the earth.
In payment for it's cooperation
during the tests, the army air serv.
ice has been given the free use OF
the process, for which patents are
pending, for the removal of mists
and fogs over it's flying fields.
Tested Over Year
The experiments have been in
progress at McCook field here for
the last year and a half, and will
be continued at Moundsville, w,
Va, on the Washington-Dayt air
route, and possibly at Washington
where fog conditions are more >fre
quent and better than at Dayton
In making the announcement OF
his successful experiments, Mr.
Warren said that elaborate scien
tific researches have shown that
a particle OF atmospheric moisture
carrying an electric charge has a
tendency to grow in size, even un-
der conditions so adverse to en-
largement as to cause unchanged
drops to evaporate; the theory be-
ing that the electric charge dimin-
ishes the surface tension of the
drops and thus facilitate further
condensation and coalescence.
In the experiments, La Pere
plane, carrying about. eighty pounds
of sand, of about $50 mesh, with a
wind-driven generator operating an
electric, equipment capable of charg.
ing the sand with high voltages,
either positively or negatively at
the will of the operator, was en-
ployed. The sand was charged to
approximately 10000 volts. or a
charge of the order of .0006 electric
static units per grain. and was scat
tered through the action of the plane
propeller at a heighth of about 500
feet above the tops of the clouds,
about 100 miles per hour.
The time taken to precipitate and
destroy the clouds, from the period
of the first direct attack to the
period of final disappearance, in
utes and in several cases was less
He pointed out that the tempered
ture and general climatic conditions
were variable, as shown by the
months of the recorded experiments
April Is, June 20, July 10, August /,
August s., November IA and other
times, as shown by affidavits of air
service officers and others
Character of Clouds
Ill H. Il AGrS ~
rem said, varied in from several
thousand feet in length and breadth,
to several miles; the thickness from
500 feet to 1.500 feet; the altitude
from $500 to 10000 feet, and par
took for the most part Of the ma
ture of Cumulus and Stratus, or
haze-like clouds, which consist of
fog in a horizontal stratum, all con-
tanning slight moisture which was
quickly evaporated in the dry air
below the clouds. Some of the eX-
periments, Mr.. Warren said, were
followed by snow flurries over the
flying field, and light rainfall over
the adjacent regions. Coarse sand
that will fall rapidly over definite
locality, thereby producing quick re-
suits, will be employed for fogs and
mists, Mr.. Warren announced, Sand
powdered to sizes that will fall by
gravity. slowly through. the varying
winds and be widely dispersed. will
be employed for artificial rain-mall-
ing. One or more tons of minute
dust particles as fine or finer than
talcum powder, and having trillions
of particles per cubic centimeter
that, when scattered. will cover
enormous areas, will be carried by
a plane flying seventy or eighty
miles per hour, and liberated as a
catalytic agent, at the rate of about
twenty-five to thirty-five pounds per
minute.
How Rain Is Made
Mr.. Warren explained that scien-