ly spontaneous Discharges. 207 



two coatings of the jar through the perforation in its side. Being 

 now satisfied that the latter spark did not depend on the mode 

 in which the discharge was effected, I proceeded to connect the 

 upper part of the inside coating of the jar in six different points 

 with the chain, by means of three pieces of metallic wire placed 

 -in the jar diameterwise, their opposite ends pressing somewhat 

 stiffly against its opposite sides. The jar was then charged and 

 discharged twice, as before ; and at each discharge the spark 

 again occurred at the perforation without any sensible difference 

 in its appearance: but on attempting to repeat the experiment 

 the third time, the charge exploded before it had arrived at it« 

 former intensity; and on examining the perforation there were 

 now found several fractures proceeding from it, through one or 

 other of which the jar, during every succeeding attempt to 

 charge it, continued to explode ; notwithstanding several expe- 

 dients were employed to prevent it. The jar having thus be- 

 come unable to retain a charge sufficient for the purpose in 

 view, and the other damaged ones appearing to be so fractured 

 as to forbid any attempt to employ them, 1 was unable to pro- 

 ceed further in the inquiry, and obliged to rest satisfied with 

 having ascertained the following facts : 



1. That when a Leyden jar, under the circumstances already 

 described, is charged to a certain height, and then discharged 

 in the usual way, — the charge will separate or divide itself into 

 two portions, one of which will pass through the metallic me- 

 dium employed to produce the discharge ; while the other por- 

 tion will pass from one coating of the jar to the other, through 

 the perforation in its side. 



2. That this separation of the charge takes place with every 

 mode of discharge by which a spark is elicited at the ball of the 

 charging wire. 



3. Tiiat when tlie charging wire communicates in several 

 points with the upper part of the coating, all other circumstances 

 remaining the same, the separation of the charge still ensues - 

 and the ratio of its separated portions to each other experiences 

 no sensible alteration. 



Should future experiments show that this phaenomenon de- 

 pends on the limited aod imperfect communication with the in- 

 side of the jar, it would afford information of much practical 

 usefulness. If, on the contrary, it should be found to be wholly 

 independent of that circumstance, the investigation of its cause 

 would still be interesting, as its discovery would perhaps throw 

 additional light upon the other singular phaenomena of the Ley- 

 den jar. These considerations, together with the uncertainty 

 whether I may hereafter have the oj)portunity and means of re- 

 suniiiig and completing the inquiry, liave induced me to lay it 



before 



