224 PHILOSOPHICAL TRANSACTIONS, [aNN0 1771. 



counting for the phenomena of electricity, is not new. ^pinus, in his Tenta- 

 men Theoriae Electricitatis et Magnetismi, has made use of the same, or nearly 

 the same hypothesis; and the conclusions he draws from it, agree nearly with 

 Mr. C.'s, as far as he goes. However, as Mr. C. has carried the theory much 

 farther than he has done, and has considered the subject in a different, and in a 

 mor? accurate manner, he hopes the Society will not think this paper unworthy 

 their acceptance. 



The method he proposes to follow is, first, to lay down the hypothesis ; next, 

 to examine by strict mathematical reasoning, or at least, as strict reasoning as 

 the nature of the subject will admit of, what consequences will flow from thence; 

 and lastly, to examine how far these consequences agree with such experiments 

 as have yet been made on this subject. In a future paper, he intends to give the 

 result of some experiments he was making, with intent to examine still further 

 the truth of this hypothesis, and to find out the law of the electric attraction 

 and repulsion. 



Hypothesis. — There is a substance, which Mr. C. calls the electric fluid, 

 the particles of which repel each other, and attract the particles of all other 

 matter, with a force inversely as some less power of the distance than the cube : 

 the particles of all other matter also repel each other, and attract those of the 

 electric fluid, with a force varying according to the same power of the distances. 

 Or, to express it more concisely, if we consider the electric fluid as matter of a 

 contrary kind to other matter, the particles of all matter, both those of the 

 electric fluid and of other matter, repel particles of the same kind, and attract 

 those of a contrary kind, with a force inversely as some less power of the dis- 

 tance than the cube. For the future, he would be understood never to com- 

 prehend the electric fluid under the word matter, but only some other sort of 

 matter. 



It is indififerent whether we suppose all sorts of matter to be indued in an equal 

 degree with the foregoing attraction and repulsion, or whether we suppose some 

 sorts to be indued with it in a greater degree than others; but it is likely that 

 the electric fluid is indued with this property in a much greater degree than other 

 matter; for in all probability the weight of the electric fluid in any body bears 

 but a very small proportion to the weight of the matter; but yet the force with 

 which the electric fluid therein attracts any particle of matter, must be equal to 

 the force with which the matter therein repels that particle; otherwise the body 

 would appear electrical, as will be shown hereafter. To explain this hypothesis 

 more fully, suppose that 1 grain of electric fluid attracts a particle of matter, at 

 a given distance, with as much force as n grains of any matter, lead for instance, 

 repel it: then will ] grain of electric fluid repel a particle of electric fluid with 

 as much force as 71 grains of lead attract it; and 1 grain of electric fluid will 



