In 1820, the Danish professor Hans Christian Oersted, realized an experience in which it demonstrated for the first time the relation between electricity and magnetism. The experiment was to place a magnetized needle parallel to a wire that would be traversed by an electric current. Thus, Oersted observed that, upon closing the circuit key, the wire was driven by an electric current, and at that instant the needle immerged deflected its north-south orientation.
This fact had already been observed when a magnet was approaching a magnet needle, when the key was opened, the current flow stopped and the needle returned to its normal position, in this way the relation between electricity and magnetism was discovered.
In the eighteenth century, the American scientist Benjamin Franklin had attempted to explain the electrical phenomena of attraction and repulsion. In his theory, he accepted that all bodies had a kind of “electric fluid,” responsible for such phenomena.
By having friction, some bodies lost that fluid, others received it and without friction, these bodies remained in their neutral state with equal numbers of negative and positive fluids. According to these ideas, since it is a matter of transferring electricity from one body to another, there would be neither creation nor destruction of electric charges, the total amount of electric fluid being constant.