Experiments and Observations on Electricity Made at Philadelphia in America
Franklin reports a series of electrical experiments conducted in Philadelphia, communicated as letters to London Fellow of the Royal Society Peter Collinson. He establishes the concepts of positive and negative charge, demonstrates that the force in a Leyden jar resides in the glass itself rather than the water or wire, and proposes that lightning is an electrical phenomenon. The work culminates in his suggestion that pointed iron rods connected to the ground could protect buildings and ships from lightning strikes.