The New York herald., 1921-08-14
Doing Justice to the Thunderstorm
Although Among the Most Terrifying of Natural
Phenomena 1t Is Less Dangerous Than Motor Car.
BY JACQUES w. REDWAY.
Fellow American Meteorological Society


companies showing that in Canada
the efficiency OF lightning rods is 97.2
per cent.
In the vicinity of New York Bay
most of the thunderstorms travel in
a V-shaped windrow from a westerly
to an easterly quadrant, and the path
along which the storm sweeps may be
anywhere from fifty to more than two
hundred miles in length. In the vi
cinity of New York city the first ap-
pearance of a thunderstorm is the
dense threatening cloud that gathers
in the northwest. Thunderstorms oc-
cur on about thirty-five days Of the
year. In 1920 fifty thunderstorms oc-
Cured on thirty-seven days.
| The high topped summer cloud the
cumulo- nimbus of the weather man
and the thunderhead Of the layman, is
the factory of the thunderstorm. The
| thunderhead is in most violent COM
motion within itself. Within it's mass
up drafts are carrying a column OF
air two, three and even four miles
high. The air is laden with moisture
| in the form of vapor. When the
moisture Is condensed to raindrops a
great amount Of heat is set free and
this adds to the vigor of the up draft
| driving with such force against the
raindrops that they are shattered into
mist.
The shattering of the raindrops sets
free an enormous quantity Of cleo
tricity; and the passage of the cleo
trlcity between cloud and cloud or be-
tween cloud and earth constitutes the
lightning. This explanation Of the
workings of a thunderstorm is some
thing more than theory. DR.. Simp-
son, now head of the British Meteoro-
logical Office, produced miniature
thunderstorms by shattering falling
drops Of water. Airmen have added
their testimony to the fact that the
up drafts of the thunderhead are
strong enough to shatter the drops.
A simple experiment, within the
reach Of the possessor Of few feet of
garden hose. goes long way to con-
firm Simpsons experiment by prov
ing it's converse. The nozzle of the
hose Is adjusted so that the water
elected becomes fine spray. II now
a vulcanite ruler be rubbed with a
bit of silk and held near the spray
the droplets will be electrified and will
at once gather into very large drops
which fall to the ground as though
they were shot.
Nature cannot be trapped into a
one way arrangement. If charging
droplets Of water with electricity
causes them to coalesce into large
drops then breaking the large drops
into spray releases the electricity.
Actual operations within the thunder
head are not quite SO simple. but they
do not differ in principle from the
foregoing description.
Earthquakes possibly excepted, 1t is
doubtful IL any natural phenomenon
Is more terrifying than tkunderstorms
but few of the greater phenomena of
nature are less destructive to life and
property. A single summer hot spell
is far more fatal. And IL one is in
doors away from open windows and
metal pipes the danger from light
ming stroke practically is zero. The
nervous person who is subject to
fainting spells should be in the COM
pany OF some one with steady nerves;
but only one person in one-quarter of
q million Is killed by lightning.