Instead of placing the magnet perpendicular to the plane of the loop, it may be placed parallel to its plane. Fig. 14d shows the magnet and loop both vertical.
The field shows that the magnet will be rotated, and will finally take for stable equilibrium an axial position, with the N end pointing as determined by the rule already given.
Fig. 14d.
If two loops are placed with their axes in the same straight line as follows, Figs. 14f, 14g, a reproduction of Figs. 14b and 14c will become evident.
It is obvious from these spectra that the two loops attract or repel each other according to the direction of the current, which fact may be shown by bringing a loop near to another loop suspended from the ring stand, Fig. 9, or by using the ordinary apparatus for that purpose—De la Rive's battery and Ampere's stand.
Fig. 14f.
Fig. 14g.