Page "Magnetic field" Paragraph 7

Three discoveries challenged this foundation of magnetism, though.

First, in 1819, Hans Christian Oersted discovered that an electric current generates a magnetic field encircling it.

Then in 1820, André-Marie Ampère showed that parallel wires having currents in the same direction attract one another.

Finally, Jean-Baptiste Biot and Félix Savart discovered the Biot – Savart law in 1820 which correctly predicts the magnetic field around any current-carrying wire.