There are many experiments which support this view.  For example, if we heat a magnet red hot it loses its magnetism, perhaps because the heat has disarranged the particles and set the molecular poles in all directions.  Again, if we magnetise a piece of soft iron we can destroy its magnetism by striking it so as to agitate its atoms and throw them out of line.  In steel, which is iron with a small admixture of carbon, the atoms are not so free as in soft iron, and hence, while iron easily loses its magnetism, steel retains it, even under a shock, but not under a cherry red-heat.  Nevertheless, if we put the atoms of soft iron under a strain by bending it, we shall find it retain its magnetism more like a bit of steel.

It has been found, too, that the atoms show an indisposition to be moved by the magnetising force which is known as hysteresis.  They have a certain inertia, which can be overcome by a slight shock, as though they had a difficulty of turning in the ranks to take up their new positions.  Even if this molecular theory is true, however, it does not help us to explain why a molecule of matter is a tiny magnet.  We have only pushed the mystery back to the atom.  Something more is wanted, and electricians look for it in the constitution of the atom, and in the luminiferous ether which is believed to surround the atoms of matter, and to propagate not merely the waves of light, but induction from one electrified body to another.

We know in proof of this ethereal action that the space around a magnet is magnetic.  Thus, if we lay a horse-shoe magnet on a table and sprinkle iron filings round it, they will arrange themselves in curving lines between the poles, as shown in figure 28.  Each filing has become a little magnet, and these set themselves end to end as the molecules in the metal are supposed to do.  The “field” about the magnet is replete with these lines, which follow certain curves depending on the arrangement of the poles.  In the horse-shoe magnet, as seen, they chiefly issue from one pole and sweep round to the other.  They are never broken, and apparently they are lines of stress in the circumambient ether.  A pivoted magnet tends to range itself along these lines, and thus the compass guides the sailor on the ocean by keeping itself in the line between the north and south magnetic poles of the earth.  Faraday called them lines of magnetic force, and said that the stronger the magnet the more of these lines pass through a given space.  Along them “magnetic induction” is supposed to be propagated, and a magnet is thus enabled to attract iron or any other magnetic substance.  The pole induces an opposite pole to itself in the nearest part of the induced body and a like pole in the remote part.  Consequently, as unlike poles attract and like repel, the soft iron is attracted by the inducing pole much as a pithball is attracted by an electric charge.