While Benjamin Franklin is known as a statesman and diplomat, he was also an accomplished inventor and scientist. Franklin was mainly a writer by professional, but he also investigated natural phenomena, such as ocean currents and lightning. His marine research led to his publication of a map of the Gulf Stream currents. Franklin developed theories about electricity, made famous by his experiment with a kite and a key during a lightning storm. As a result of his work with electricity, Franklin invented the lightning rod, which provided buildings from lightning strikes . Always curious and imaginative, Franklin also invented the bifocal glasses, the Franklin stove, an odometer for carriages and a musical instrument called a glass harmonica.