The Red Cloud chief., 1881-06-16

and sucked in below by the inaowins
currents, each tiuc adding to their coat
ing OF snow and ice before their fina
fall TO earth.
When the tornado is very small il
the area covered by the gyratory mo
ton. a land spout or a water spout il
formed, as it may happen to occur on
Hand or at sea. In these the gyratOry
velocity rapidly diminishes with dis
lance from the center. Their destruct
i've effects are sudden and often great
but the area of violence is small. j.
the center Of a waterspout, as i'm f':a'
of a tornado when in full force, RAIN
falls or water descends in ar i1fln'
though a heavy shower Off. Iai,s III
the vicinity. On land dr. a nSns
substances are carried - anu d 'hey
are being collected f1m 81. SUES Wy
currents coward tue vortex
below. thew ass,.iie the form OF a cone,
which meets the descending spout.
fallino ann emily from the clouds, and
Thus Give the whole phenomenon the
a~nnesr.nce of an hour-glass.
re observed diameter Of water
srJuts range between two and Two
hundred feet or more, and their heights
from thirty to fifteen hundred feet.
sometimes very much more; but none
of these observations can be regarded
as at all exact. With a high tempera-
ture and a very low dew point Mr.. Fer
rel calculates that a water spout might
reach a mile i'm height, but such condi-
tions must occur rarely. Water spOuts
are often observed to drop down from a
cloud in an incredibly short space OF
time, and TO be drawn up again in the
same manner; but this is all an Illusion
When the gyrations are such as TO not
quite reduce the tension and iempera-
ture i'm the center, SO rs to condensc the
aqueous vapor and make il visible, a
very slight increase at once reduces the
temperature sufficiently. and the spout
appears from top TO bottom almost in
simultaneously. just the reverse OF this
takes place, when the spout breaks, and
il seems to be drawn up instantly; it is
dissolved, not lifted. Tornadoes and
waterspouts originate only in an I'M
stable state of equilibrium OF the air,
which requires an unusually rapid de-
CttdSc vi temperature "it ihSiNdoN Va
altitude. This can take place only
when the strata nearest the earth are
unusually heated; accordingly they
never occur at night or in the
winter, and but rarely in cloudy
weather. If any agitation of the air,
such as that arising from the discharge
of cannon. tends to break up these me-
teors, then any considerable disturb
ance of the air from any u must
tend to prcvent their formation. Hence
they occur at sea and OF the lakes only
when there is little or no wind.
White squalls are invisible spouts.
In such cases the dew point is so low,
and the cloud when formed so high.
that the gyrations are invisible. Still
the gyratious and the rapidly ascending
current in the central part are there,
and also the rising and the boiling OF
the sea. Over the boiling sea, high up
in the air, is a patch of white cloud.
formed by the condensation OF the
vapor when it reaches the required
height. The bulls-cye squalls on the
west coast of Africa arc of precisely the
same nature. In these cases the air is
too dry to furnish the cloud necessary
To make the spout, or center of the
gyratory movement, visible.
In hot, dry climates these ascending
whirls of air form sand spOuts or pillars
of sand. Both water spouts and sand
spouts arc hollow. -Scientifc american.