ELECTRICAL PROPERTIES OF SILK. l65 



)laced a riband that was not quite dry under an- 

 )ther that was well dried at the fire, upon a smooth 

 >lain; and when he had given them the usual 

 Hction with his ruler, he found that, in what 

 nanner soever they were removed from the plane, 

 the upper one was negatively, and the lower one 

 positively electrified. If both ribands were black, 

 all these experiments succeeded in the same man- 

 ner as with the white. If, instead of the ivory 

 ruler, he made use of any skin, or a piece of smooth 

 glass, the event was the same ; but if he made use 

 )f a stick of sulphur, the electricities were in all 

 3ases the reverse of what they had been before the 

 ribands were rubbed, having always acquired the 

 >ositive electricity. When he rubbed them with 

 paper, either gilt or not gilt, the results were un- 

 certain. When the ribands were wrapped in paper, 

 jilt or not gilt, and the friction was made upon the 

 }aper laid on the plane above mentioned, the rib- 

 ands acquired both of them the negative electricity. 

 If the ribands were one black and the other white, 

 whichever of them was laid uppermost, and in 

 whatever manner the friction was made, the black 

 generally acquired the negative, and the white the 

 positive electricity. 



He also observed, that when the texture of the 

 upper piece of silk was loose, yielding, and retiform, 

 like that of a stocking, so that it could move and 

 be rubbed against the lower one, and the rubber 



