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Franklin didn't actually discover electricity

Monday, May 27, 2002

By Michael Woods, Post-Gazette National Bureau

PHILADELPHIA -- No scientific experiment -- except, perhaps, the detonation of the first atomic bomb -- is more familiar to the public than Benjamin Franklin's legendary kite experiment.

(Ted Crow, Post-Gazette)

As famously depicted by numerous artists, Franklin and a boy fly a kite in a field during a terrible thunderstorm. Lightning strikes the kite and an arc of electricity flies from a key on the kite string to Franklin's finger.

Eureka! Ben Franklin "discovers" electricity.

But as next month's 250th anniversary of the experiment approaches, questions remain whether it was a true scientific advance, a meaningless stunt, or historical hogwash.

Simplistic portraits of the experiment may underlie doubts about its reality and importance, said Claude-Anne Lopez, author of several books on Franklin. For instance, a lightning strike would have killed or seriously injured both Franklin and the boy. And the individual depicted as a small boy actually was Franklin's 21-year-old son, William.

"Franklin was an amazing individual," Lopez said. "Statesman, philosopher, author, bon vivant, newspaper publisher, revolutionary, businessman, a kid who was taken out of school at age 10, ran away from home, and learned everything he knew from reading. Maybe the idea that he also was brilliant scientist just strains the limits of belief."

"The kite experiment was quite real," said H. W. Brands Jr., a historian at Texas A&M University and author of "The First American: The Life and Times of Benjamin Franklin."

"Historians of science today still consider his work among the most significant of the 18th century. For this experiment, and related work, he received the era's equivalent of the Nobel Prize, and was hailed as one of the great scientists of the age."

However, the experiment did not make Franklin the discoverer of electricity.

The ancient Greeks knew about electricity. Thales of Miletus, who died around 546 B.C., discovered that static electricity could be made by rubbing amber with wool. The word "electron" originated in a Greek word for amber.

Scientists in Europe experimented with electricity long before Franklin.

Biographers say Franklin became interested in one of the era's greatest mysteries -- the nature of electricity -- in 1746 after reading about experiments done in Europe.

In Franklin's day, scientists were struggling to understand basic principles of electricity, such as attraction and repulsion. Franklin did coin today's terms for the types of attraction -- positive and negative. He introduced other common electrical terms such as "battery," "plus" (for positive charges), "minus" (for negative charges), "electrician," "electrified," and "charge."

Franklin turned his Market Street home in Philadelphia into an electrical laboratory, using jerry-built instruments made from household items. He brought electricity into the house dangerously -- via a wire leading from an iron rod attached to the chimney.

"On the staircase opposite my chamber door, the wire was divided, the ends separated about 6 inches, a little bell on each end," Franklin wrote in one letter to friend and fellow inventor Peter Collinson in London.

Franklin's famous electric bells signaled when electricity was in the atmosphere and available for use in his experiments. Sometimes the bells chimed softly when small sparks jumped between the wires. Sometimes they rang. Franklin described huge arcs of electricity, as thick as his index finger, which lit up the staircase like bright sunlight.

The gadgets terrified Franklin's wife, Deborah, who wanted to disconnect the electric bells.

One experiment was nearly fatal.

While trying to kill a turkey by electrocution, Franklin accidentally shocked himself. He blamed the mistake on boisterous house guests, gathered to view the spectacle, who distracted him. The shock threw Franklin to the floor, where he flopped in convulsions.

"In the beginning, electricity was a game, a parlor trick," Lopez explained. "They had traveling electricians who amused people with demonstrations. Franklin moved beyond that, and began building a hypothesis that lightning is electricity, and then developed an experiment to test the hypothesis."

Franklin observed similarities between lightning and the stuff in the parlor tricks.

Both lightning and electricity looked like light, appeared in forked arcs, crackled, and could kill animals. He described the experiment to prove that electricity and lightning were one in the same -- the electric kite experiment -- in a letter to Collinson.

Collinson published the letter in 1751, and European scientists were quick to try the experiment. At least one was electrocuted before a French scientist named Thomas-Francois D'Alibard succeeded in Marly, France, in May 1752. Scientists in England and Belgium also did the experiment before Franklin.

News was slow to reach the New World in those days, and Franklin probably was unaware that others had beaten him to the punch, according to Lopez.

Franklin planned to test his ideas about lightning not from a kite, but from the steeple of Christ Church, which then was under construction in Philadelphia.

By spring of 1752, the steeple was still unfinished, and Franklin, growing inpatient, decided to use the kite. The experiment took place sometime in June 1752, with the exact date never recorded.

Franklin and his son, William, were the only witnesses. Everything known about the actual experiment appeared in an account published 15 years later by Franklin's friend Joseph Priestley, the British chemist who discovered oxygen. Franklin read the account before Priestley published it.

It was the classic "never-try-this-at-home" experiment. Ben and his son escaped with their lives because lightning never actually struck the kite. Rather, it encountered small amounts of electricity collecting in the storm clouds.

The kite carried a wire intended to attract electricity and channel it down the string to a metal key. By some accounts, Franklin touched the key when he saw threads on the string stand on end, signaling the presence of electricity. A spark jumped to his finger, proving that lightning and electricity were one and the same.

Franklin's discovery that lightning was a huge electrical spark had immediate practical and scientific impacts.

"He went from an idea, to proving the idea with an experiment, to applying the experimental results in designing a lightning rod to protect property," Lopez noted.

The lightning rod consisted of an iron rod attached to the top of a building, connected to a wire that carried lightning strikes harmlessly into the ground. Franklin's lightning rods sprouted in Philadelphia, New York, Boston, and all over Paris and London.

King George III, who despised Franklin's anti-British politics, was furious. The king ordered his science adviser to denounce Franklin's design as faulty. The adviser refused, declaring that even a king couldn't change the laws of science. George fired him on the spot.

Franklin's work also encouraged other scientists.

Italian physician Luigi Galvani, for instance, had fashioned a crude battery made from metal placed in fluids from a frog's body. Dissected frogs twitched when connected to the battery. Galvani though it was due to "animal electricity," a special force found only in living things.

After reading about Franklin's experiment, Galvani took dissected frog legs outside during an electrical storm and found that they also twitched. It led other scientists, including Alessandro Volta, to show that muscles contracted not because of "animal electricity" but because of the same electricity as in Franklin's electric kite.

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