Licence: Public Domain Mark
Credit: On the lines of magnetic force / Professor Faraday. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![1852. WEEKLY EVENING MEETING, Friday, January 23. Sir John P. Boileau, Bart., F.R.S, V.P. in the Chair. Professor Faraday, ] On the Lines of Magnetic Force. That beautiful system of power which is made manifest in the magnet, and which appears to be chiefly developed in the two extremities, thence called ordinarily the magnetic poles, is usually rendered evident to us in the case of a particular magnet by the attractive or repulsive effect of these parts on the corresponding parts of another magnet; and these actions have been employed, both to indicate the direction in which the magnetic foi’ce is exerted and also the amount of the force at different distances. Thus, if the attraction be referred to, it may he observed either upon another magnet or upon a piece of soft iron; and the law which results, for effects beyond a certain distance, is, that the force is inversely as the square of the distance. When the dis- tances of the acting bodies from each other is small, then this law does not hold, either for the surface of the magnets or for any given point within them. Mr. Faraday proposes to employ a new method, founded upon a property of the magnetic forces different from that producing attraction or repulsion, for the purpose of ascertaining the direction, intensity, and amount of these forces, not to the displacement of the former method but to be used in conjunction with it; and he thinks it may be highly influential in the further development of the nature of this power, inasmuch as the principle of action, though different, is not less magnetic than attraction and repulsion, not less strict, and the results not less definite. The term line of magnetic force is intended to express simply the direction of the force in any given place, and not any phy- sical idea or notion of the manner in which the force may be there exerted; as by actions at a distance, or pulsations, or waves, or a current, or what not. A line of magnetic force may be defined to be that line which is described by a very small magnetic needle, when it is so moved in either direction corre-](https://iiif.wellcomecollection.org/image/b22377001_0003.jp2/full/800%2C/0/default.jpg)
