Magnetization.
That matter virtually remembers its impressions is plain when we study magnetism. Steel when magnetized for the first time does not behave as when magnetized afterward. It is as if magnetism at its first onset threw aside barriers which never again stood in its way. If the steel is to be brought to its original state it must be melted and recast, or raised to a white heat for a long time. In quite other fields of channeled motion we remark that violins take on a richer sonority with age; their fibres, under the player’s hand, seem to fall into such lines as better lend themselves to musical expression.
In 1878 the late Professor Alfred M. Mayer of the Stevens Institute of Technology, Hoboken, New Jersey, published a series of remarkable experiments in the “American Journal of Science.” He there told and pictured how he had magnetized several small steel needles, thrust through bits of cork set afloat in water, the south pole of each needle being upward. As the needles repelled each other, or had their repulsion somewhat overcome by a large magnet held above them with its north pole downward, the needles disposed themselves symmetrically in outlines of great interest, which varied, of course, with the number of needles afloat at any one time. Three needles formed an equilateral triangle, four made up a square, five disposed themselves either as a pentagon or as a square with one magnet at its centre, and so on in a series of regular combinations, all suggesting that magnetic forces may underlie the structure of crystals.
Mayer’s floating magnets.