Northern tribune. [volume] (Cheboygan, Mich.) 1875-1885, 1884-05-15
Local Warnings Against Tornadoes.

LOcai warnings Against T0rnadOes.
I have lately examined with some
care the excellent compilation by Ser
geant Finley. of the Signal Service,
characteristics of Six Hundred lorna
does" with reference to the question OF
devising a simple apparatus for saving
human life. Saving property seems to
be out OF the question, as no structure
can Withstand the force of the tornado
wind. Life may be saved by recourse to
underground shelters, cellars, etc., such
as have actually been built in many
places for this end. Two facts may be
quoted from the work named: First
Three hundred and forty-seven out of
three hundred and ninety-three lorna
does Chat is, eighty per cent? origi-
mated between the west and the south
southwest points; Second-The average
velocity OF progression was about one
mile in two minutes. . . If five
minutes warning could have been given
at any of the late tornadoes, many lives
might have been saved. If each house.
hold could be warned by the continuous
ringing OF a bell, for example, that a
wind of destructive force (say seventy
miles per hour and upward) was APP
preaching, and that five minutes were
available in which to seek shelter, this
would be well worth doing.
l have found that it is practicable to
erect, at a moderate expense, Qess than
5000, an apparatus which would give
from three to five minutes warning to
all the inhabitants of a small town, by
the firing OF a cannon, for instances; and
in addition, and without any increased
expense, this apparatus could ring a bell
in every house. The additional ex-
pense to each house would be less than
ten dollars, the cost of maintenance
would be less than one hundred
dollars a year, and the work would be
done by an intelligent person. The
system, for a small town, would be
something like the following: Suppose a
circle described about the town with a
radius of from two to two and one-half
miles. The only serious danger from
tornadoes is to be feared from the part
of this circle between the west point
and the southwest point. Along the
circumference of this circle, between
the south-southwest and west points,
run a line of single telegraph-wire on
twenty posts to the mile, and from the
west point bring the wire into the town,
letting it end at the telegraph office. 1t
is grounded at each end of the line, and
at the telegraph Office it is connected
with a battery, which sends a constant
current over the line. Within the town,
connection is made in various houses
with magnets. Each magnet holds a
detent, which prevents q bell from being
rung by the action of a cheap clock
work governed by a coiled spring. II
the circuit is broken anywhere in the
line, each bell begins to ring, and con-
tinues to sound till its spring is run
down; for four or five minutes for ex-
ample. A cannon could be fired by a
simple device, which would warn per.
sons in the fields, etc., to seek shelter.
one of the engine-houses of the fire de-
partment, and ring a bell there. This
would be the signal for the man on
watch to repeat the warning simulta.
neously through as many local circuits,as
desirable.
1t remains to indicate the way in
which the circuit is to be broken by the
wind. The circuit of telegraph poles
from the south-southwest to the west
points would contain about fifty poles.
On every one of these the wire would
run first to an insulator, then to an
iron horizontal axis screwed into the
side Of the post. On this axis a piece OF
board one foot square a revolve freely.
An iron rod projects below this board,
and from the lower end of it a small
wire goes to a pin in the telegraph-pole.
This pin is connected by wire to second
:asulator. From this the line goes to
the next pole, and so on. The circuit
ordinarily passes to the first insulator,
thence to the iron rod, thence down the
iron rod to the thin wire, through the
pin to the second inSulator, and SO to the
next telegraph-pole. The thin wire ia Q
necessary part of the circuit 1t is SC
made that j twill break when the pressure
of the wind on the square board is fifty
pounds. The apparatus for each post il
tested practically before it is set up.
This a be done at any time in asimple
manner Whenever any single one 81
these boards is subjected to the pressure
of fifty pounds, its wire will be ruptured.
and the circuit will be broken, thu!
sending the necessary warning along
the whole line. 1 have made one suck
Indicator, which is connected with s
small bell in this observatory. The
wire is arranged SO that it breaks ats
wind-velocity of about ten miles pei
hour, and it works in a perfectly sue
cesssul manner. The extension of the
system for the protection of q small towr
is a simple matter. For a large city
q moro expensive system would
have to be provided, as the wires be-
tween poles should be carried under.