?9S On the PhiBnorneTia of -the El^cfropkoms^ 



app.iratas is conformable to that ot an electrophorus : tlis 

 glass representing the electric ca-;e, and the upper and 

 lower plate the cover and so^.e, all in their natural state. 



'* Q.. The gia^s helno- tlius furnished with a nietalhc coat- 

 jno; on each gide, iuid having a proper communication with 

 the ground, will admit of beir-g cliarged ; and both coatings 

 may be separated and examined apart witl\out destroying; 

 the insulation of either. 



'' 3. "i'lie apparatus being thus disposed, conmiunicate a 

 strong charge to tlic glass by means of the bent wire ; then 

 remove the charging wire and the chain connected with the 

 lower plate- On the approacli of a finger to the upper coat- 

 ins a small spark will pass, and the same will happen to 

 the under coatino:. This eflect cannot be produced twice 

 bv two succeeding applications to the same coating; but 

 in a favourable state of the atmosphere may be repeated 

 iionic hundred times, by aJternate applications to the two 

 coatings, till the charge of the glass is gradually exhausted. 



** -1. Let the glass be again fully charged ; touch the 

 upper coaling with the finger, and then, by its insulating 

 stem, separate it from the upper and positive Burface of the 

 glass : this coating will then be found negative ; i. e. oppo- 

 site to the fcide of the glass with which it was in contact. 

 This elTect, on repetition, gradually diminishes; but oij 

 touching the coatings alternately two or three times, the 

 negative power of the coating when separated is greatly in- 

 creased, so as to yield strong negative sparks. The same 

 circumstances will happen to the under coatuig; substituting, 

 however, the positive for the negative t-ffects. 



'* 5. Each surface of tlie charged glass therefore, in con- 

 sequence of a momentary interruption of the insulation, has 

 the power of producing a contrary electricity in the coating 

 in contact with it : more electrical matter must have passec} 

 away from the upper coating at the time of touching it tharj 

 the same coating could receive from the upper surface of 

 the glass, and therefore the upper coating, by losing some 

 of its natural quantity, becomes negative : more electric 

 matter must in the same manner have been added to the 

 under coating, which becomes positive. The greatest de- 

 gree of this influential power will be produced in either coatr 

 ing by taking care at the same time to bring the opposite 

 coating into a like slate of influential electricity. 



*' 6. The glass being well charged, let a bent wire in the 

 form of a staple be brought into contact-with the upper 

 and lower coating at the same time: bv this a discharge 

 Hill be effected, but the equilibrium will be only in part 



restored j 



