. Handbook of nature-study for teachers and parents, based on the Cornell nature-study leaflets. Nature study. 838 Handbook of Nature-Study THE MAGNET Teacher's Story NTIL comparatively recent times, the power of the mag-net was so inexplicable that it was regarded as the working of magic. The tale of the Great Black Moun- tain Island magnet described in the "Arabian Nights Entertainments"—the story of the island that pulled the nails from passing ships and thus wrecked them— was believed by the mariners of the Middle Ages. Pro- fessor George L. Burr assures me that this mountain of
. Handbook of nature-study for teachers and parents, based on the Cornell nature-study leaflets. Nature study. 838 Handbook of Nature-Study THE MAGNET Teacher's Story NTIL comparatively recent times, the power of the mag-net was so inexplicable that it was regarded as the working of magic. The tale of the Great Black Moun- tain Island magnet described in the "Arabian Nights Entertainments"—the story of the island that pulled the nails from passing ships and thus wrecked them— was believed by the mariners of the Middle Ages. Pro- fessor George L. Burr assures me that this mountain of lodestone and the fear which it inspired were potent factors in the development of Medieval navigation. Even yet, with all our scientific knowledge, the magnet is a mystery. We know what it does, but we do not know what it is. That a force unseen by us is flowing off the ends of a bar magnet, the force flowing from one end attracted to the force flowing from the other and repellent to a force similar to itself, we perceive clearly. We also know that there is less of this force at a point in the magnet half-way between the poles; and we know that the force of the magnet acts more strongly if we offer it more surface to act upon, as is shown in the experiment in drawing a needle to a magnet by trying to attract it first at its point and then along its length. That this force extends out beyond the ends of the magnet, the child likes to demon- strate by seeing across how wide a space the magnet, without touching the objects, can draw to it iron fihngs or tacks. That the magnet can impart this force to iron objects is demonstrated with curious interest, as the child takes up a chain of tacks at the end of the magnet; and yet the tacks when removed from the magnet have no such power of cohesion. That some magnets are stronger than others is shown in the favorite game of "stealing tacks," the stronger magnet taking them away from the weaker; it can also be demonstrated
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