Obfervations on tht Theory of EUUric JltraBion. 465 



That tK^ attraftion fubfifllng between two bodies in oppofite dates of ele£lrlcity may be 

 explained, it is neceffary to confider previoufly the cafe of two bodies in their natural or 

 ordinary ftate. In this cafe the force fubfifting between each body and its own portion of 

 the cledric fluid is not in a ftate of faturation, becaufe it muft be fufficiently ftrong to 

 counterbalance the elafticlty of the fluid. Each body is therefore ftill capable of being 

 attrafted by the fluid belonging to the other, and each portion of the fluid is alfo capable 

 of fuch attraiElion. This force, if it fhould operate alone, would draw the bodies toge- 

 ther ; but the mutual repulfion of the two portions of the fluid tends to produce the oppo- 

 fite effeft. The quiefcence of the bodies proves the equality of thefe forces. 



If two bodies in oppofite ftates of eleftricity be brought together, the body pofitively 

 eleftrificd cannot be attrafted towards the remaining ele£lric fluid belonging to the other, 

 becaufe this body may be confidered as faturated with the fluid, and that portion of the 

 fluid as faturated with folid matter. For the oppofite reafons an attradlion will take place 

 between the body negatively eleflrified and the fluid belonging to the former. It remains 

 to be fliewn, that this attradlive force may exceed the mutual repulfion of the two portions 

 of fluid. It mufl; be obferved, that the repulfion remains the fame, becaufe the fum of the 

 two quantities of fluid is not altered; whereas the attra£lion is augmented by the unequal 

 diflribution of the fluid. The one body is charged with more fluid than that which its 

 own attrafting force is capable of retaining, and the redundant fluid will confequently be 

 ftrongly impelled towards the other body, whofe attradlive power is at the fame time in- 

 creafed by the deficiency of its own portion of fluid. 



In the cafe of two bodies fimilarly eleflrified the bodies may be either both pofitively, or 

 both negatively ele£lrified. When they are both pofitively eledtrified, they are both fatu- 

 rated with the eleftric fluid ; and when they are both negatively eledtrified, both remaining 

 portions of the eledlric fluid are reciprocally faturated with folid matter. In neither cafe 

 therefore can any attraftion take place between either body and the fluid belonging to the 

 other. Confequently, the repulfion exifting between the two portions of the fluid muft 

 operate without reCftance, and the two bodies be repelled from each other. 



Should this folution of ele£lric attra£lion and repulfion be admitted, it will perhaps alfo 

 remove the difllcu!^ of magnetic repulfion. In this part of philofophy it has been found 

 difiicult to explain the repulfion of the correfponding poles agreeably to the theory of a 

 magnetic fluid. In every magnetical body the equilibrium of this fluid is fuppofed to be 

 difturbed, and one part of the body is conceived to be overcharged with the fluid, whilft 

 the other is undercharged. The difficulty was to explain the repulfion of the undercharged 

 poles, as in eleftricity to explain the repulfion of bodies negatively eleftrified. Mr. Kirwan 

 has indeed, in a Memoir contained in the Sixth Volume of the Tranfadlions of the 

 Academy, referred the phsenomena of magnetlfm to cryftallization ; but his mention of 

 the term faturated in that Memoir feems to imply, that he does not mean to exclude the 

 fuppofition of a magnetic fluid. If this be adopted, the preceding folulion may be applied 

 to the phenomena of magnetifm, in the fame manner in which it has been already applied 

 to thofe of eleftricity. 



Vol. IV. — January 1801. 3O The 



