Bismarck daily tribune. [volume] (Bismarck, Dakota [N.D.]) 1881-1916, 1912-07-08
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= DR.. S1EiNME1Z TALKS =
= ABOUT LIGHTNING. =
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In a recent paper read before the
Electrical Section Of the Franklin In
stitute, DR.. Charles Proteus Stein
metz, the electrical genius OF the
General Electric Company, disclosed
some very interesting facts about
lightning and thunder in general.
I'm the early days lightning was
explained as the discharge Of the
Clouds" says DR.. Steinmetz, "The
clouds were thought to be positively
charged, and the ground negatively
charged. the sparks jumping from the
cloud to the ground. Speculations
were made as to how the clouds be-
came charged, and as then the only
method Of producing electricity was
by friction, it was said it might be
the friction of the vapor through the
air, or the rain drops through the air,
or some other form Of friction. That
explanation used to appear satisfac.
tory, but with our present knowledge
of d~ielectric phenomena, it is not
satisfactory any more.
1T was thought that lightning was
the discharge from the cloud to the
ground. That means that the electric
field between the cloud and the
ground must be beyond the break
down strength Of air. In a uniform
field the breakdown strength Of air
is about $4,000 volts per inch, or near
" a million volts per foot. Even II
the cloud is only 1000 feet above the
ground, this would require a thousand
million volts. II there were an cleo.
trostatic field between the cloud and
the ground Of a thousand million volts
extending v e the whole area Of the
thunder cloud, this would represent
such an immense amount Of electric
energy that 1t Is uncomfortable how
any reasonable source of energy can
produce 1t; how 1t a exist without
having a destructive effect far beyond
anything known of lightning. Furth-
ermore, a uniform field cannot we'll
exist between clouds and ground, on
account of the unevenness Of the
ground surface.
We cannot consider the lightning
discharge as a simple electric rupture
In the same way that an overloaded
beam may break mechanically, but as
an equalization Of internal stresses,
such as a piece OF hot glass that Is
rapidly chilled and thereby full OF
internal compression and tension
strains, suddenly breaking all over by
the internal stresses. So with our
present knowledge we must consider
this as the most probable explanation
not certain by any g
the lightning discharge Is the
phenomenon Of the equalization Of in
ternal electric stresses in the cloud,
and is analogous to the splintering or
breaking Of an u~nevenly stressed brit
tie material, like glass. Lightning
discharges are the result of the volt
age inequalities produced In the
clouds by the unequal rate OF con-
glomeration Of rain particles due to
the unequal cloud density. 4
I'm. agreement with this Is mat
heavy lightning strokes are usually
followed by a heavy downpour OF rain
in reality they are preceded and caus-
ed by it, but it takes time for the
rain drops to come down.
"The lightning rod is q great pro-
lection and l would not like to be IN
an exposed place without such protec.
tion. But you must not expect that
one rod on one end Of the building
will completely protect the other
= hundred or more feet away. There
must be sufficient rods to extend their
protective zone over the entire area;
the apex OF the roof, and other pro.
jecting edges must be protected by
connecting wires, etc. That Is, like
any other apparatus, the lightning roo
protection must be installed intelli-
gently and properly to be effective.
But the general principle is correct.
only 1t must be nationally applied
The reflection on the people OF the
western part of the state about the
alleged resubmission influence on the
voting is resented by the people OF
that section.