COMPOUND ELECTRICAL ll^STRUMENT. Ql 



plate B will come near A, and D will remove away from C ^^^ yfcs as a 

 Ml I • 1 • 1 • n L condenier, a 



till the wires b and/touch one another, at which inftant the fmgie and double 



wire </ touches the wire ^. Now if the plate E and F are multiplier, and 

 near one another, they will form a third condenfer, and nearly ei^-^ricity. 

 the whole of the charge of D is communicated to E in the 

 fame manner the charge of B was communicated to C ; at the 

 fame time B recruits its charge by coming near A, which will 

 be communicated to C, which induces a contrary ftate on D, 

 and which D communicates to E, and this operation is re- 

 pealed every time the lever Is moved backwards and forwards; 

 fo that the charge on C is increafing at every motion of the 

 lever, while the charge on A remains the fame ; and when C 

 becomes fo much charged as not to be capable of receiving 

 any more from B (which will be the cafe in a certain number 

 of motions) the operation will ftill go on between D and E, 

 the charge on E increafing while the charge on C remains the 

 fame, fo that E will acquire a charge as much greater than C 

 as the charge on C is greater than the charge on A, which will 

 be manifefled by removing the plate F away from E. When 

 the wire a is fcrewed into the plate A, and conne6ted with E 

 by means of the wire 4 5; the inftrument then pofleflTes all the 

 properties of the double of electricity, for then all the charge 

 communicated to E (which is of the fame nature as that of A) 

 will be communicated to A, which will continually increafe the 

 intenfity of its charge, and that will have an increafed efFe6l 

 on B, &c. at every motion of the lever. There is no limits to 

 this accumulation, but that where the charge is fo intenfe as to 

 pafs from one plate to the other in the form of a fpark. 



I have made many experiments with this inftrument relative On the fpon- 



to its fpontaneous electricity, and I find, as a tingle multiplier ^^"?°"^ 5'^^* 

 ,,. , ,^ •'. ^,.,7^. tricity of thjj 



(that is when an electrometer is connetied with C) it has no inftrument. ' 



efFed on the moft delicate gold leaf eleflrometer I could make; 



but as a double multiplier (that is when an eleflrometer is 



conneded with E) there is fome fmalleffed if fome eledricity 



had been communicated to it within an hour or two, although 



it may have been difcharged by touching each of the plates with 



a metal point (which I find is the moft efFedual way of dif- 



charging fmall portions of eledricity,) but if it has ftood three 



or four hours after being difcharged, it will not give any figns 



of eledricity. When ufed as a doubler it always becomes 



elei^irified with between eight and fixteen motions of the lever, 



2 evj^n 



