This is an experiment which might prove interesting. We know , thanks to the work of Oersted and Ampere , that the field around a wire carrying a current and the field around a permanent magnet are identical. Both of these fields are caused by moving charges , although the field around a wire is thought to be due to the oscillation of ions in the crystalline lattice structure of the wire carrying a current , while the field around a permanent magnet is attributed to the alignment of spin of the electrons within the substance of the magnet. It is well known that a permanent bar magnet when suspended by a string will align itself in the direction of the earth’s magnetic field . What I wish to know is how would a wire carrying a current , align itself when suspended in a similar manner , would the wire align itself in the direction of the earth’s magnetic field or would it align itself differently. The experiment can be performed as follows. A straight wire is suspended horizontally from a string and a beam of electrons from an electron gun is directed at it in such a manner that the electrons impinge on one end of the suspended wire , causing a current to flow in the wire. It is possible that some sort of tracking device would be necessary in order to ensure that the current flows in the wire for a sufficient time in order for the wire to align itself. If the wire , when a current is flowing through it , aligns itself in the direction of the earth’s magnetic field , does it demonstrate that the field around a wire carrying a current and the field around a bar magnet are identical (i.e solenoidal ) fields. As a corollary to this , it follows that all electrical wires carrying an electrical current result in solenoidal (closed) fields ,since the current is essentially flowing between the two poles of a dipole , i.e between the positive and negative poles.