A wealthy printer and publisher, he was one of the signatories to the peace between the USA and Great Britain after the War of American Independence. His main scientific achievements were the formulation of a theory of electricity, based on the concept of an electric fluid, which introduced (and arbitrarily defined) positive and negative electricity, and a demonstration of the electrical nature of lightning, which led to the invention of the lightning conductor. His inventions include the ‘Franklin stove’ (a kind of free-standing cast-iron heater) and bifocal spectacles.