ELECTRICAL PROPERTIES OF SILK. 165 
placed a riband that was not quite dry under an- 
other that was well dried at the fire, upon a smooth 
plain; and when he had given them the usual 
friction with his ruler, he found that, in what 
manner 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 
of a stick of sulphur, the electricities were in all 
cases the reverse of what they had been before the 
ribands were rubbed, having always acquired the 
positive electricity. When he rubbed them with 
paper, either gilt or not gilt, the results were un- 
certain. When the ribands were wrapped in paper, 
gilt or not gilt, and the friction was made upon the 
paper 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 
he rubbed against the lower one, and the rubber 
