A Study in Magnetism

Abstract

THE name of Faraday will go down to posterity foremost amongst the names of the scientific men of this century, for the simple comprehensiveness and original beauty of his researches in electricity and magnetism; chiefly, perhaps, for his discovery of magneto-electricity—the kind of electricity that can be induced in conductors which are caused to pass near magnets. Those who have carefully read Faraday's works know how he was led to this discovery by the conception he had formed of magnetic force. Until his time magnetic attractions and repulsions had been explained as a kind of action-at-a-distance. Faraday explained them as the results of the action of the medium filling the intervening space; and he gave several indisputable proofs that the space surrounding a magnet was thrown into a peculiar condition by the presence of the magnetism. Two centuries previously another Englishman, as uniquely great if not greater, Dr. Gilbert, had in his famous treatise “De Magnete,” told how iron filings sprinkled on a piece of card beneath which a magnet lay, assumed certain mysterious lines. To these lines Faraday gave the name of lines of force, and showed that they represented, wherever they went, the direction and strength of experiment. In the volumes of his researches he filled several entire plates with drawings of the figures assumed by the lines under various combinations. They had taught him to anticipate magneto-electricity and electromagnetic rotation. He had diligently followed them up from the hint afforded by Dr. Gilbert's experiment with the iron filings. He had begun to apply the method to the investigation of the interaction of electric currents when the decay of age overtook him, and the research dropped from his grasp. Had he lived the study which the writer of the present article is about to narrate-would have been completed long ago.