In post 25.10, I used a special case of the Biot-Savart law to define magnetic field. This law is named after the French physicists Jean-Baptiste Biot (1774-1862) and Félix Savart (1791-1841). But in post 25.15, I described how magnets were known long before Biot and Savart were born. Since magnets attract ferromagnetic material, they must… Continue reading 25.16 Biot-Savart law