430 New Outlines of Chemical Philosophrj. 



that the electrical elements pass through glass instantaneously, 

 I ordered a glass ball three inches diameter to be blown with a 

 long neck, tliat a thermometer-tube might be sealed into it 

 with the blow-pipe. But as the artist to whom I gave the or- 

 der did not execute it so soon as he might have done, he gave 

 Bie an opportunity of trying what might be done without his 

 assistance. 



It is well knowni to every tyro in this science, that animal sub- 

 stances are better conductors of electricity than glass. On this 

 principle I supposed tliat the electrical elements might be pre- 

 vented from entering into a glass phial, as effectually as if its 

 mouth were hermetically sealed. 



To try what might be done on this principle, I procured a 

 Florence flask, and fitted into the top of its neck a glass stopper, 

 but not by grinding, for that was not necessary in this experi- 

 ment. To the lower part of the glass stopper, one end of a 

 strip of Dutch plate-glass, a quarter of an inch in breadth, was 

 fixed with sealing-wax ; to the other end two slips of Dutch leaf, 

 each an inch and a half in length and a quarter of an inch in 

 breadth, were fixed. The strip of glass being suspended in the 

 axis of the flask, its neck and stopper were covered with moist 

 bladder. 



The palm of the hand being laid upon the stopper, and an 

 excited barometer-tube carried over the back of it with a vibra- 

 ting motion, not the least effect was produced in the leaves within 

 the flask ; for all the electricity communicated to the hand was 

 conducted to the floor, through the person of the experimenter*. 



But the flask being taken up by its neck and an excited tube 

 of glass held under the bottom of it, at the distance of two or 

 three inches, the leaves instantly diverged ; and when the tube 

 was caused to vibrate horizontally, even to the number of four or 

 five times in a second, the same number of vibrations were per- 

 formed, in the same time, by the leaves within the flask: and 



he same phcenomena were produced bv a rubbed stick of sealing- 

 •vax, though in a less degree. 



These experiments demonstrate in the most satisfactory man- 

 ner, that glass is permeable by the electrical elements, and that 



ney pass through it instantaneously, both by induction and di- 



ect communication. 



Exp. 6. A brass ball properly insulated will become elec- 

 trified by induction, as soon as a charged barometer-tube is 

 held over it at a proper distance, but in a state of electricity 

 contrary to that of the tube. 



• When the top of the flask is perfectly covered with the hand, the 

 bladder is uimccessai v. 



The 



