Like
a youthful George Washington chopping
down the cherry tree, Benjamin Franklin
flying the kite in the lightening storm is an image known to every school
child. Unlike the cherry tree myth,
Franklin really did fly a kite in a storm on June 10, 1752.
It
was the most spectacular of the Philadelphia
sage’s experiments with electricity which earned him world wide acclaim as
a scientist. The adventure would also
have world-wide political implications.
Born
in Boston in 1707, Franklin’s
amazing career is too rich and varied to recount here. Suffice it to say after Franklin arrived in
Philadelphia as a 17 year old run-away apprentice in 1723 he was a printer,
writer, author, editor, and publisher;
businessman; post master; local official; militia officer; inventor; scientist,
philanthropist, founder of the first insurance company, fire brigade, and hospital
in the colonies; founder of the University
of Pennsylvania and the American
Philosophic Society; colonial agent in Britain;
delegate to the Continental Congress
and member of the committee which drafted the Declaration of Independence; diplomat and Minister to France; President of Pennsylvania, and member of the Constitutional Convention. Whew! And that leaves out a lot.
By
1752 Franklin was semi-retired from his successful printing businesses and
focusing his attention on his electrical experiments. Franklin, experimenting with a Lyden Jar, a container for storing an
electrical charge, had already proven the existence of positive and negative
electrical charges and shown them to both be forms of the same “electrical
fluid.” He had also described conservation of a charge. These were critical advances in scientific
learning.
In
1750 he published a paper describing a kite experiment to show conclusively
that lighting as a form of electrical discharge. Adapting his experiment to an
iron rod instead of a kite Frenchman Thomas-François Dalibard succesfully proved Franklin’s hypothesis in May 1752.
Of course Franklin would have no way of knowing that when
he took his son and faithful assistant William
out to an open area near the edge of the city that day to finally execute
the experiment himself. Under
threatening skies he attached
his kite to a silk string, tying an iron key at the other end. A thin wire was wound around the key run into
a Leyden jar. A silk ribbon was tied to the key for Franklin to hold.
He
launched the kite as the storm approached and once it was aloft, moved under
the cover of a barn so that he would not get wet. As the thunder storm cloud
passed over Franklin’s kite, negative charges in the cloud passed onto his
kite, down the wet silk string, to the key, and into the jar. Franklin,
standing on dry ground inside the barn and holding the dry ribbon was insulated
from the negative charges on the key. When he moved his free hand near the iron key,
a spark jumped from the key to his exposed knuckle because the negative charges
in the key were so strongly attracted to the positive charges in his body.
He
had successfully shown that lightning was static electricity. Franklin was lucky to have survived the
experiment. Others who tried to
duplicate it were electrocuted, including noted Russian scientist Georg Wilhelm Richmann.
Franklin would have died too, had lightning actually
struck the kite. He was aware of that
danger. Which is why he flew his kite
early in the storm close to the clouds where it picked up electrical discharges
without actually being struck by lightning.
A supremely practical man, he quickly turned his
discovery to use with the invention of the lighting
rod which protected buildings from deadly lightning strikes which every
year were responsible for many fires and deaths.
His findings made him one of the most famous men in the
world. The prestigious Royal Society awarded him its Copley Medal in 1753 and elected him a Fellow of the Society, an honor granted
to few Colonials, in 1756. Franklin also did pioneering work on the wave
theory of light, meteorology, cooling by evaporation, heat conductivity, and
oceanography over his long life.
Franklin’s fame as a scientist and as the author of pithy
sayings in his famous Poor Richard’s
Almanac, opened many important doors for him when he became agent for
Pennsylvania and other colonies in London
from 1757 to 1775. When he arrived
in France as American Minister in 1776, he found himself the object of public
adoration and private respect due in no small measure to his enormous
scientific reputation. With an in to the
great Salons of Paris he carefully exploited his fame and cultivated relationships
that would pay off for the struggling new nation first with significant loans,
then with official recognition, and finally with French troops on the ground
and a fleet off shore that bottled up unfortunate General Cornwallis and the
main British Army at Yorktown.
A good case for that can be made that it was all due to
that George Washington owed his most
famous battle field victory to that dangerous experiment in 1752.
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