Delaware gazette and state journal. (Wilmington, Del.) 1883-1902, 1900-03-22
rHroarsE or rHrNnER.
A Theory Suggested for Something Not Yet
Understood.

A Theory Suggested for Something Not Yet
Understood.
Electrical Review.
What is the cause of thunder, mean
ing. the cause Of the noise? We do not
know. The thunder, We know, is a
result of the phenomenon we call
.'lightning," but Just what 1t is has
not been as yet adequately determined.
The electric discharge produces q
variety Of effects, physiological, lumi-
nous, caloritic, magnetic, mechanical
and chemical, whose characteristics are
more or less well recognized. 1t is fair
10 presume that we must hunt for the
cause of the noise in the calorific,
mechanical or chemical attributes.
Most of the authorities in definition
say thunder is the noise Immediately
following flash Of lightning, and is
due to the distui Dances OF the air
caused along its path by the discharge,
and they let it go at that 1t may be
thut the real explanation will be found
partly in each of the oalorific, mechani-
cal and chemical actions. A mere dis
turbance of the air is hardly an ade-
uuate reason. We have too little owl
dence to 60 upon. The heating effects,
SO called, may have some bearing. We
know the spark will inflame ether,
alcohol, and some of the hydrocarbon
gases; yet it does not ignite gunpowder,
except by the help Of a wet string which
becomes heated. A Leyden jar charged
and discharged several times in rapid
succession becomes heated. All solid
conductors become heated by it. But
does arr Mechanical effects are
numerous and usually disastrous to any
solid body not good conductor. We
are shown BY Kinnersley's Thermometer
that some effect is produced on body
of water, but it is asserted not to be
due to any increase of temperature In
the air.
The chemical effects are most varied.
Priesrly found reduction Of volume
in moist air by passage of the spark
(which may be signifirant), and that
the air became acid. Cavendish
found this was due to the formation of
nitric acid by the chemical action of
the discharge. Compound gases are
readily decomposed. but air is not a
compound gas it is merely mixture
of oxygen and nitrogen, and neither OF
its constituents Is oombustible.t One
assists combustion of other bodies,
while the other is inert in that sense.
But we may get some light on tho
subject yet from the indefatigable army
of electrical Investigators. Possibly,
the researches in the liquefaotion Of
gases may help out. Ip recent paper
on the subject 10 Is stated that ozone
liquefies at atmospheric pressure at a
temperature of l35. A degrees Fahren-
heit, and that it is easily exploded.
Now, it is we'll known that the electric
discharge produces this so-called allo-
tropic oxygen in great abundance. Ac-
cording to Priestly the electric dis
charge effects reduction of volume in
moist air, which would indicate ordi-
narily fall of temperature. Moist air
is the usual atmospheric condition
during lightning flashes. Possibly the
| stream OF innumerable sparks in q
stroke of lightning PRODUCES q cumula-
| tive or intensive effect, first lowering
the temperature, then forming ozone,
then causing its liquefaction, and
finally its explosion, or perhaps detona-
| tion, which expresses more accurately
| the terrifying crash following or accom-
papyIng a lightning stroke near at
hand. This is mere speculation, and
give it for what 1t is worth.