New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1882-06-22

moisture into visible cloud. Wserspouts arc gener-
ally formed during period OF great neat anu arc
most frequent in the calm regions between She
tropics. The observer first notices a dark cloud
from which there projection III the
shape of an inverted cone. AS this projection De-
comes larger and extends downward, the water IND
mediately underneath is heaped up and agltated
violently By this time tho whirling motion which
began in tho clouds has reached the water. ana Is
probably continuous throughout, although part
of the whirlng column has not yet been made visi-
bio by the condensation of moisture INTO cloud
The extension Of the projection from the clouds Is
not due according to Professor Ferrel, to the
descent of vapor but the visible condensation OF
tho vapor of the sprally ascending air currents
arising from an increasing rarefaction due to the
accelerated rate of the gyrations the condensation
being similar to that of the cloudseen In exhauStng
an aiG-pump. As the whirlmg of the upper part Oh
the waterspout becomes more intense the rareiac-
ton of the air within is increased and the condeh
saton into cloud continues downward until the en-
tire column is visible. Then there is roaring
noise like that of great waterfall but
within moderate distance around the waterspout,
q calm usually prevails. AS soon as the rapdty OF
the rotary motion is lessened the condensation OF
vapsr is diminished and the column gradually
breaks up and disappears the cloud sometimes dis
charging itself IN rain.
The water under the waterspout is agltated De-
cause tho atmospheric pressure beneath the column
IS less than the pressure around it. This fact is il
Illustrated In another way when a tornado on land
passes over a closed building. In many such cases
the walls and roof OF tho house have been thrown
out violently, showing that the pressure outside
was suddenly and largely diminished and the air
within as suddenly expanded. In this way the tor
nado works great mart of its destruction to life and
property. The progressive motion of tornadoes and
whrlwlnds varies greatly the rate being, probably,
that of the general movement OF that portion OF the
atmosphere of which they are part. Tornadoes
sometimes occur at comparatively low elevations
without reaching down to the surface of the earth,
and in such cases they rage with violence on the
hill-tops leaving intervening valleys unharm ed
During the onward movement tOrnadGs sometimes
rise above the surface tor short time and then de-
scend again. 1t is not improbable that the wind
sometimes reaches force in tornad9s exceeding
what is ever reached in cyclones, but 1t does not
blow for so long time OF travel 50 far as in the
cyclone.
Some meteOroogists, assuming that tornadoes
were formerly confined almost exclusively to the
Immediate neighborhood of the tropics, point to
every tornado that in the West and North
west as an evidence that the climate of the United
States is undergoing important notifications the
character and extent of which can only be dmly
guessed at" 1t is more probable however, that
the supposed in OrnadOes is due TO the fact
that as the country becomes more thickly settled
fewer storms pass by unnOticed. In these days OF
telcgraphs and railroads all disastrous storms are
promptly reported, but when the country was
thinly settled storms seldom heard OF lar from
the places where they occurred.
------------