Chap. 4.] EleRrtcal Spider. 331 



explofion, becaufe, both fides being infulated, the bot- 

 tle was not charged ; but if a chain is fufpended from 

 the brafs ball of the phial to the table, and the coat- 

 ing brought in contact with the conductor, after a 

 few turns of the machine remove the phial as be- 

 fore ; then if the discharger is applied, an explofion 

 will be heard, and the bottle will be difcharged ; be- 

 caufe, in this cafe, the infulation of the infide is de- 

 ilroyed by the chain, and the phial becomes capable of 

 receiving a charge. 



That the charge of a coated jar refides in the glafs, 

 and not in the coating, is proved in the following 

 manner: let a plate of glafs between two metallic 

 plates, about two inches in diameter^ fmaller than 

 the plate of glafs j charge the glafs, and then re- 

 move the upper metallic plate by an infulated handie j 

 take up the glafs plate, and place it between two other 

 plates of metal uneteftrified and infulated, and the 

 plate of glafs thus coated afrefh will ftill be charged. 

 The following experiments are further ' illuftrative of 

 the nature of the Leyden phial. 



A cork ball, or an artificial fpider made of burnt 

 cork, with legs of linen thread, fufpended by filk, wiil 

 play between the knobs of two bottles, one of v/hich. 

 is charged pofuively, the other negatively, and will in 

 a little time difcharge them. 



A ball fufpended on filk, and placed between two 

 brafs balls, one proceeding from the outfide, the other 

 from the infide of a Leyden jar, when the bottle is 

 charged, will fly from one knob to the other, and by 

 thus conveying the fire from the infide to the outfide 

 of the bottle will foon difcharge it. 



An infulated cork ball, after having received a fpark, 

 will not play between, but be equally repelled by two 

 bottles, which are charged with the fame power. 



A wire 



