The silver star., 1900-03-23
SCIENTIFIC TOPICS.
CURRENT NOTES OF DISCOVERY
AND INVENTION.
Causs Of fhandsr = Mystsry-s scisncs
Has Bssa Uaabie t. Account fer the
Phsnonsnon- Barhsrs scissors and
Conbs-Ceaeh asd Cradle.

What is the cause Of thunder. mean
ing the cause of the noise? We do net
know. The thunder. we know, Is
result of the phenomenon we call
lightning" but just what II Is has not
been as yet adequately determined.
The electric discharge produces . Va
riety OF effects. Psychological. lumin-
GUS, caloridc, magnetic, mechanical ana
chemical, whose characteristics are
more or less well recognized. 1t is fair
to presume that we must hunt for the
cause OF the noise In the calorinc, me-
chanical or chemical attributes. Most
of the authorities in definition say
thunder is the noise Immediately fol-
lowing q Hash of lightning. and Is due
to the disturbances of the nir caused
along Its path by the discharge. ana
they let it 60 at that. 1t may be that
the real explanation will be found part
ly in each of the calorific. mechanical
and chemical actions. mere dis-
turbance OF the air is hardly an ade-
quate reason. We have too little evil
dence to go upon. The heating ef-
fects, so called, may have some bear
ing. We know the spark will infiame
ether. alcohol and some of the hydro
carbon gases; yet 1t does not ignite
gunpowder. except by the help OF
wet string which becomes heated.
Leyden jar charged and discharged
several times in rapid succession be-
comes heated. But does air? Mechan-
ical effects are numerous and usually
disastrous to any solid body not good
conductor. We are shown by Kinners-
ley's thermometer that some effect Is
produced on a body of water. but 1t Is
asserted not to be due to any increase
Of temperature in the air The chemi-
cal effects are most varied. Priestly
found reduction Of volume in moist
air by passage of the spark (Which
may be Significantly and that the air
became acid. Cavendish found this
was due to the formation OF nitric acid
by the chemical action OF the dis
charge. Compound gases are readily
decomposed, but air is not a compound
gas; 1t is merely mixture OF oxygen
and nitrogen, and neither OF its con-
stituents is combustible. One assists
combustion of other bodies, while the
other is inert in that sense. But We
may get some light on the subject, yet
from the indefatigable army of cleo
trical investigators. Possibly the re-
searches in the liQuefaction OF gases
may help out. In recent paper on
the subject 1t is stated that ozone
liquefles at atmospheric pressure at q
temperature OF 1854 degrees Fahren-
heit and that it is easily exploded.
Now. 1t is well known that the electric
discharge produces this so-called al
lotropic oxygen in great abundance.
According to Priestly the electric dis
charge effects a reduction Of volume
in moist air. which would indicate or
dinarily fall of temperature. Moist
air Is the usual atmospheric condition
during lightning flashes. Possibly the
stream of innumerable sparks in a
stroke OF lightning produces q cumula-
tive or intensive effect. first lowering
the temperature. then forming ozone.
then causing Its liquefaction, and final
ly its explosion. or perhaps detonation.
which expresses more accurately the
terrifying crash following or accom-
panying lightning stroke near at
hand. This IL mere speculation. and
I give It for what 1t is worth.-Electri-
cal Rovlaw