of this passage from one polarity to neutrality, and to that of the
opposite name, will there be found a break of continuity of rotation or
haphazard arrangement. If we rotate this rod slowly, horizontally or
vertically, taking observations at each few degrees of rotation of an
entire revolution, we find still the same gradual symmetrical change
of polarity, and that its symmetry is as complete at neutrality as in
evident polarity.

In all these cases there is no complete neutrality, the longitudinal
polarity simply becoming transversal when the rod is east and west.
F, G, H, I, J, Fig. 1, show this gradual change, H being neutral
longitudinally, but polarized transversely. If, in place of the rod,
we take a small square soft iron plate and allow its molecules freedom
under the sole influence of the earth's magnetism, then we invariably
find the polarity in the direction of the magnetic dip, no matter in
what position it be held, and a sphere of soft iron could only be
polarized in a similar direction Thus we can never obtain complete
external neutrality while the molecules have freedom and do not form an
internal closed circle of mutual attractions; and whatever theory we may
adopt as to the cause of polarity in the molecule, such as Coulomb's,
Poisson's, Ampere's, or Weber's, there can exist no haphazard
arrangement in perfectly soft iron, as long as it is free from all
external causes except the influence of the earth; consequently these
theories are wrong in one of their most essential parts.

We can, however, produce a closed circle of mutual attraction in iron
and steel, producing complete neutrality as long as the structure is not
destroyed by some stronger external directing influence.

Oersted discovered that an external magnetic needle places itself