On April 21, 1820, Hans Christian Oersted was delivering a lecture when he first noticed that a compass needle deflected from magnetic north when the electric current of the battery was switched on and off. This confirmed a direct relationship between electricity and magnetism.
Oersted first thought that magnetic effect radiate from all sides of a wire carrying electric current but later when he did his research, he found out that electric current produces a circular magnetic field as it passes through the wire.
Apart from electromagnetism, Oersted also discovered aluminium. Humphry Davy had first discovered the alloy aluminium-iron. However, Oersted was the first person to isolate aluminium from an alloy of aluminium chloride.