American politician and scientist Benjamin Franklin (1706–1790) was a tireless inventor. By 1748, he had made enough money from various businesses to concentrate on scientific research and inventing new devices. Among his many creations were bifocal glasses, a metal-lined fireplace called the Franklin Stove, the musical instrument known as the glass harmonica (for which Handel, Mozart and Beethoven wrote works) and, most famously, the lightning rod. Franklin was one of the key Founding Fathers of the United States and signatory to the United States Declaration of Independence in 1776.

Lightning rod

In June 1752 Franklin attached a metal key to one end of a kite string and flew the kite in a stormy sky. Franklin took steps to ensure he was insulated, so that the electricity would not flow through his body and electrocute him. By showing that sparks jumped from the key to his hand, he proved that lightning was a form of electricity. His experiments lead to his invention of the lightning conductor (lightning rod), a metal rod attached to a high building and connected to the ground. If lightning were to hit the structure, it would strike the rod and be conducted to the ground through the wire, instead of passing through the building where it could start a fire or even cause an explosion.