Elements of electricity, magnetism, and electro-magnetism : embracing the late discoveries and improvements : digested into the form of a treatise, being the second part of a course of natural philosophy : compiled for the use of the students of the University at Cambridge, New England / by John Farrar.
- John Farrar
- Date:
- 1826
Licence: Public Domain Mark
Credit: Elements of electricity, magnetism, and electro-magnetism : embracing the late discoveries and improvements : digested into the form of a treatise, being the second part of a course of natural philosophy : compiled for the use of the students of the University at Cambridge, New England / by John Farrar. Source: Wellcome Collection.
Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.
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![axis, and having their bent extremities Z, C, Z', C', immersed in cups filled with mercury, so as to admit of their readily taking a motion of oscillation by which they might approach to, or recede from each other. It ]^ sufficient to connect the mercury of these cups, or their supports with the poles of the voltaic apparatus, in order to produce the tVvO combinations of figures 162, 163. Now the aitraclion and repulsion of the conductors, as ob- served by M. Ampere, were always such as the construction of these figures indicates and enables us to foresee. 284. M. Ampere proposed to make these phenomena the fun- damental principle of the whole theory of electro-magnetism, by considering them, not as compound results in the way we have done, but as simple efiects resulting from an attraction or repul- sion, which the electric currents would exert upon each other immediately, without sensible tension, according as they are transmitted through the metallic conductors in the same direction or in opposite directions. This hypothesis, which attributes to fluid currents an attractive property, depending on their differ- ent or similar directions, is iti the first place, completely opposed in itself to all the analogy observed in the other laws of attraction. It would, moreover, be necessary to modify it by another en- tirely arbitrary circumstance, in order to deduce from it the varialion of intensity which is observed in the transvci'se action of the elementary laminae of the uniting wire, according to the obliquity of their direction to the lines which separate them from the magnetic particles subjected to the action ; whereas this par- ticular may be considered as only a compound result of the unknown distribution of the elementary magnetism, when we attribute the magnetic action of the wires to such an action. Finally, upon the latter supposition, the influence of the uniting wires upon magncls is referred to the general analogy of the action of magnetic bodies upon each other; while, in order to explain this influence according to the hypothesis in question, M, Ampere is obliged to make a multitude of other si ill more compli- cated suppositions; for he is under the necessity of considering all the mutual actions of magnetic bodies in general, as pro- duced by voltaic currents circulating about the metallic particles which compose them, in a manner greatly resembling the vortices of Descartes. Ilonce arises a complication of arrangements and suppositions very difl'icult to be explained ; while, on the other](https://iiif.wellcomecollection.org/image/b21051483_0376.jp2/full/800%2C/0/default.jpg)
