Omaha daily bee., 1903-06-14

north of the present location of the belt of
high pressure and also far inland. This
favorably located district in the summer
season causes a strong indraft of moist,
vapor-laden air from the gulf and Atlantic
coasts, and these indrafts of saturated air,
on reaching higher attitudes, condense,
forming cloud sheets, and thus producing
rain. 1t is true that the above described
circulation is annual, and hence of no I'M
usual occurrence, and has repeated thai
circulation for ages without bringing flood
conditions. This fact alone, then, leads to
the examination OF the air itself at this
particular time to discover II possible the
causes of these unusual results.
Floods Due to Excess of Dust in Air.
! The presence of an excess of dust, Of
whatever nature IL may be, in the atmos-
phere supplies man. little solid bodies and
I surfaces, upon which the vapor can con-
dense into mist and form cloud and rain,
thus producing an excess of rain that would
not otherwise fall. 1t is a very generally
accepted fact that pure air, which is laden
with vapor, must be reduced many degrees
below the point OF saturation, or rain point,
of impure air, before its vapor will begin
to condense into mist or cloud. Some me-
teorologists go so far as to claim that pure
air cannot be made to give up It's moisture
at any temperature, however low it may be
I reduced. and can be made to give up its
moisture only by the introduction Of dust
particles and impurities.
When the temperature of Immense vol
umes of moisture-laden air is falling,
caused either by conventional circulation
or by the drifting of the whole current from
lower to higher ATTITUDES, the little solid
particles of dust in the air give up their
temperature more readily than the air IT.
self. thus exposing millions of little cool
surfaces, which. in turn, extract the heat
from the surrounding saturated coat OF air,
and when the temperature is thus drawn
from this surrounding saturated coat OF air
II gives up a fixed per cent Of its moisture,
which coats the little dust particle or i'm
purity with a thin layer of water, thus
forming mist or cloud. These little particles
of mist run together. increasing in size
until they form water drops; then they fall
10 the earth as rain. II the atmosphere
be pure II may fall to most any tempera-
ture without the formation of rain, for
vapor cannot condense unless II has some
solid body to condense upon. Thus. II dust
is so necessary a factor in the formation
OF rain, as 1t most evidently is, the more
dust there is in the air the more abundant
should be the rainfall. the other conditions
and factors involved ~ the process of
rainfall being present.
Volcanoes POIute the Air.
The volcanoes in the West Indies that
suddenly became active during the early
part of last year nave hurled into the at
mosphere hundreds OF thousands of tons OF
impurities, in the nature of volcanic gases
dust and ashes. These impurities have
been caught up by the primary wind cur
rents and swept over the entire earth. but
the principal amount OF them have beer
carried over the United States, and more
especially that part OF the United States
which lay in the path of the wind currents
coming from the volcanic region. The ma
jority Of these active volcanoes are located
in the belt OF the northeast trades, and
these winds have caught up this dust and
carried IT on into the equatorial belt, where
the air was heated and rose to great
heights, flowing off northward, carrying
this dust and immense quantities of vapol
with 1t. After flowing a certain distance, .
great portion OF these dust, moist-lader
currents were caught in the continental In
draft and drawn into and across the centra
part OF the United States. over what is nov
the flooded district. These currents of air
on reaching higher ATTITUDES, fell in tenn
peraNlre and their moisture began at once
to condense on the dust that was present n
an Overabundanee, and which induced con
densation and increased the rainfall Ia
beyond what II would have been had tn
volcanic dust not been present and the al
had possessed only its normal amount o
impurities. The presence of great quaint
ties OF dust In the air causes the eondensa