11£! On the Franklinian Theory of Elect ricUrj. 



he found that llie phial would not receive a charge, becaUsft 

 no fluid could be collected ; and by insulating the phial he 

 found the same result, because no opportunity of escape 

 was aftorded to the fluid f)n tlic outside ; but by forming a 

 conmiunication between the inside and outside coatings the 

 phial was charged with case : in this case it appeared evi- 

 dent that the fluid residing in the outside had been trans- 

 ferred by the action of the machine to the inside : thus it 

 appears that positive and negative electricity are insepara- 

 ble, have a constant tendency to produce and preserve each 

 other, and the increase or decrease of power on either sur- 

 liicc of a plate of glass must be regulated by the increase or 

 decrease of the contrary pov/er on the opposite side. In 

 chftroing positively no t.':radual addition of electric matter 

 can be made to one side without a proper conveyance for 

 an equal quantity to pass oflf on the other side, and in its 

 gradual discharge none can be taken from the positive side 

 without aftbrdino the negative side an opportunity of ob- 

 taining an equal quantity. The experiments of Mr. Brookes 

 have been supposed to militate against this opinion ; but 

 they seem more properly to confirm it, allowing some de- 

 gree of limitation to the general proposition : he found on 

 charging an insulated phial, by means of a pointed \\ire, 

 that in the act of charging both sides indicated positive 

 electricity; by the theory the electric fluid is driven oflf from 

 the external surface by the repulsive action of the positive 

 electricity on the internal side of the phial, and by the con- 

 finement of insulation will be constrained to pass gradually 

 throuoh the point, of course producing the efiect of accu- 

 mulation. You will probably recollect, that during the last 

 sessions your experimental committee repeated these expe- 

 riments with some additional circumstances ; and you will 

 remember, that when the phial was not insulated the fluid 

 seemed to pass oft' instantly ; and the outside, even during 

 the act of chargino-, always indicated the negative electri- 

 city. The most serious objection is derived from the dif- 

 ficulty of conceiving how a fluid incapable of percolatinsr 

 the pores of glass can act through the same pores by a 

 peculiar occult repulsive quality : but when we consider 

 the mysterious qualities of gravitation, of magnetism, and 

 even of fluids, whose disposition to rise to the same level is 

 equally unaccountable, we shall feel obliged to acknowledge 

 that tliis quality affords no rational presumption against the 

 truth of the heorv. After all, whatever judgment we form 

 of the general principle, its application in various instances 

 will be insuflicient to explain the observed phsenomena. 



Mr. 



