Invention of Electricity — Ampère


André-Marie Ampère was known as the Isaac Newton of electricity because, in the 1820s, he derived mathematical laws describing the relationship between electric current and magnetism. Ampère’s work made possible the development of electrical power. It is fair to say that electricity simply did not exist in the form that we think of it today before the work of Ampère. Certainly, the natural phenomenon of static electricity and lightning were well-know, due in large part to Benjamin Franklin’s studies during the last half of the 18th century. And, any well-equipped laboratory early in the 19th century included an electric pile, essentially a battery, for experiments in the new field of electrochemistry. It was not until Ampère described magnetism as “electricity in motion” that people began to think of electricity as something that can be used to transmit power and drive machines.

Ampère devised experiments that revealed precisely how electrical currents interact with a magnetic field. The credit discovering that electricity and magnetism are related belongs to a Danish scientist, Hans Christian Ørsted. Ampère’s experiments deftly explored the subtleties of this relationship and illustrated them before an astounded audience of his peers in the Academy of Science. A key phenomenon in understanding this relationship is the deflection of a magnetized compass needle by the magnetic field generated in the vicinity of a wire carrying and electric current. Ampère described this memorably by asking his audience to imagine a man lying along the length of the wire, oriented so that the current flows from his feet to his head, and with his left arm outstretched to the side. With the man looking in the direction of the compass needle, the north pole of the needle deflects in the direction indicated by the man’s left hand. This is rule became known as the “bonhomme d’Ampère.”

André-Marie Ampère is one of the 72 scientists and engineers named on the Eiffel Tower.



A dead poet, a reformed anarchist, and an earnest engineer celebrate the 19th century revolution in science and technology that transformed Paris and conquered the world — a collection of essays on the theme.

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William Nuttle

Navigating a changing environment — hydrologist, engineer, advocate for renewable energy, currently writing about the personal side of technological progress