Franklin's Lightning - Kite experiment (June 15, 1752) - on this date in history

from Garrison Keillor's Writer's Almanac (daily program supplied by Minnesota Public Radio):

On this day in 1752, Benjamin Franklin is believed to have performed his famous kite experiment and proved that lightning is electricity. He tied the kite to a silk string with an iron key on the end of the string. From the key, he ran a wire into a Leyden jar, a container that stored electrical charge. He then tied a silk ribbon to the key, which he held onto from inside a shed, to keep it dry. The electrical charge from the storm overhead passed through the key and into the Leyden jar.


Franklin, as it turns out, was lucky to have conducted this experiment safely. Several others who attempted it after him were electrocuted. He used the information he gained to design lightning rods, which conducted a storm's electrical charge safely into the ground. One of Franklin's lightning rods saved his own house years later, during a storm.

Although Franklin described his kite endeavor in a letter later that fall, the full account of the experiment wasn't written down until 15 years after the fact by a man who wasn't even present: Joseph Priestly. However, he wrote it after detailed correspondence with Franklin, so his account is generally believed to be reliable.