of El-ectricili/. JOI 



tci of breaking a stick of sealing-wax will produce the two 

 contrary electricities in the two contiouous extremities -• if 

 two diilerent substances be rubbed together when insulated 

 utiless the conductina" powers of these substances be pre- 

 cisclv similar, they will exhibit o])positc sions of electricity: 

 ■the mere contact between two bodies in ditierent states pro- 

 duces an apparent equilibrium, and each ceases to be cha- 

 racterized by any peculiar properties. — ^iinothcr cireum- 

 «tance which renders the theory of two fluids improbable 

 is, that the quality produced depjuds aiot only an the na- 

 ture n^ the elccti-ic, bul on that of the rubber. Those 

 electrics which with some rubbers produce positive, with 

 others pmduce negative electricity; and aJmost every elec- 

 tric may be made to produce, at pleasure, either positive or 

 iiegative electricity by the adaptation of proper rubbers. 

 The visible electric atmosphere may be adduced, as another 

 proof, in favour of the homogeneity of the electric fluid, 

 if a ball, at the termination of a brass rod whose upper 

 end is connected with the prime conductor, be inserted in 

 an exhausted receiver at a sufficient distance from another 

 ball to prevent a spark from passing between them, the 

 upper ball will have a lucid atmosphere extcndintr itself 

 towards the lower ball, while the latter is destitute of any 

 such appearance. If the upper ball be kej)t ne^ativelv elec- 

 trified by connecting it with the rubber instead'of the prime 

 conductor, the effects will be reversed, and the lov\'er ball 

 distinguished by a lucid atmosphere : thus we have an 

 ocular demonstration of the unity of the fluid ; for, if there 

 were two fluids, both s-hould liave atmospheres : under ±liese 

 various considerations 1 think we mav be justified iu ascribino- 

 all electrical appearances to thxi actioji of a single fluid. 



With respect to the elasticity of this fluid, I'much doubt 

 whether it is susceptible of proof; as, however, its elasti- 

 city is iijfcrred from its repulsive property, it will come 

 under oiir notice \n the next proposition. 



The universal diffusion of this fluid may be presumed 

 from our experience : no place has yet been found where, 

 by the usual means of excitation, electricity cannot be ob- 

 tained ; and no reason can be assigned for any partial of 

 Joeal conllncment when moisture and other conductors are 

 at Ir.md to convey it over the whole earth. It will on the 

 present occasion be superfluous to examine the identitv 

 of lightning and electricity : it will be sufiicient to observe 

 tliar, by the proper management of the electrical kite, it 

 inay ut all limes be collected from the almosphere. 



C A The 



