“Until then, electricity had been thought to involve two types of fluids, called vitreous and resinous, that could be created independently. Franklin’s discovery that the generation of a positive charge was accompanied by the generation of an equal negative charge became known as the conservation of charge and the single-fluid theory of electricity.”

“Until then, electricity had been thought to involve two types of fluids, called vitreous and resinous, that could be created independently. Franklin’s discovery that the generation of a positive charge was accompanied by the generation of an equal negative charge became known as the conservation of charge and the single-fluid theory of electricity.”

— Walter Isaacson