Man has always wished to be able to fly. Seeing how birds do it and not being able to do it has obsessed him, to the point of causing quite a few accidents. It is a craving that even very young children know. Some mishaps caused by the viewing of the movie Superman at the end of the seventies may be proof.
At the end of the 19th century, two fundamental interactions were known: electromagnetic and gravitational. In one respect, both are quite different. Electrically charged bodies can have a positive or a negative charge. A positive and a negative charge attract each other; two positive or two negative charges repel each other. Likewise, magnetic bodies have two ends with magnetism of a different type, north and south. If we bring two magnets together, the north end of one and the south end of the other attract each other; ends of the same type repel each other.
