Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1879-03-26
NUMBER ! 3.

'hii" toihauo came TO the
ground three miles north and
two miles east of the point at
which the second left the earth:
again indicated on the map that il
was only a continuation of the 9TH
ers. This tornado travelled about
hive mics due east and left the earth.
from shls point on to Lake Michi-
gan, the storm only came to the
earth III form Of a violent wind NOV
ing toward the east. Through tho
Whole course OF the tornado track
the report notes, with great deal
/, of detail, all the peculiar movements
OF .he wind as 1t played with the
habitations of men. The whlrhng mo-
tion of the wind was in the opposite
direction to the suns course; that
is the wind on the north limit of tho
tornado blew to the west and on
| the south limit to the east. This
was proven 10y the finding of build
Ings and fences and all things nova
| bic that were on the north of tho
center of the track moved to the
west Of their original location. and
south of the center OF the tornado
track things were moved east, The
forward movement of tho storm is
given at Is miles, and that of tho
tornado at 20 miles per hour. The
circular motion of the wind would
vary, of course, with the distance
from the center Of the tornado. Tho
lifting power Of the tornado is inter-
esting. The report says: "The per-
/ pendicular velocity can be approxi-
imated by She lifting force exerted
upon bodies while holding them in
suspension. At Osmonson's, horse
weighing about l,l00 pounds was
carried over twenty rods A horse
of about the same weight on the
premises of II. Palmer, Oregon, was
carried eighty rods. A horse of this
size would not expose a lifting sur
face to the wind Of over II square
feet. To lift such an animal would
require, then, an upward pressure
Of the air of llO0-li-7S.5 pound.
per square foot. This pressure is
produced by wind moving with a
velocity Of l2l6 miles per hour. At
r b. Chandler's piece OF pine SxS
inches and six feet long was carried
one-lourth mile. This timber could
not expose a greater surface to the
wind than s. square feet. Mahan
gives the specific gravity of pine as
two thirds that Of water. This irag-
ment would accordingly weigh III
pounds, and would require aa up.
, ward pressure per square foot OF
= .5J=2O pounds, and an upwarG
velocity Of the wind of 63.2 miles al
hour. At McCarthy's in the west
ern part Of Oregon, an oak sill, 0xa
inches aud 20 feet long, was carried
fifteen rods. This would expose q
surface Of about 20 square feet ant
weigh 600 pounds. The force neces.
sary to lift the weight, 30 pound.
pen square foot, would require per
pendIcular velocity Of the wind o
ia miles an nour. The grant,
boulder carried fifteen PODS on th,
F., premises Of l.. Hake, township 0
Jefferson, 10 inches square, anC
more than q inches in thickness
must have weighed more than l31
pounds To hold this rock ia sus
pension would require lifting fore
, OF 1872 lbs. per square foot of sur
face. This force would be exerte,
by wind moving with an upwar,
! velocity Of 10 miles ap hour.
large number Of similar example
might be given these, however, AZ
considered sufficient TO show th
!, very great velocity with which I'll,
winds moves IN such q storm"
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