In order to arrive at a knowledge of wherein consists the means which subvert the equilibrium between two suspended magnets, reference has to be made to the artizan's mode of operating in converting the unmagnetised bar to a magnet. He holds the bar in the middle, and draws one half along the pole of a loadstone; then draws the other half along the other pole, and after a few such alternate _rubbings_ against the poles, the bar is a polarized magnet. From which it was formerly supposed, that iron contains a magnetic fluid which the loadstone rubbings divide, and draw half to each end of the bar. But were such the fact, the ends or poles should be _equals_, whereas they are magnetic opposites. Now, with more reason, it is considered that iron includes two different, removable elements, (correlatives,) which, by the manipulation on the loadstone, are drawn one to each end of the bar, and there remain as polar atmospheres, and constitute what are termed the polarities, or opposite polarities of the bar; the latter opinion is somewhat confirmed by the corresponding manner in which iron filings, while being scattered on a sheet of paper, become arranged round the poles of a magnet lying under the paper. The magnetic relation, which the polar atmospheres of any iron magnet bear to those of every iron magnet, being the same as exists between the polar atmospheres of every individual magnet, makes manifest, that a certain pair of correlative elements is common to all magnetisable iron; but without concluding that, by the same kind of correlatives, the polarities are produced in bodies not ferruginous, which, if the physical fact, so may the animal correlatives be different in some instances. From which it follows, that no one mesmeriser can affect mesmerically every person, nor any one person be so affected by all mesmerisers. Neither are all persons "nervous" alike, which should moderate the war cry against mesmerism generally because of failure in some cases; and should awaken the philosophic mesmeriser, willing to make perfect the science, to investigate the cause of exceptions and difficulties.