ELECTRICAL PROPERTIES OF SILK. 163 
the paper-hangings of the room. He repeated the 
experiment, and found it would continue hanging 
near an hour. Having stuck up the black and 
white stockings in this manner, he eame with an- 
other pair highly electrified; and applying the 
white to the black, and the black to the white, he 
carried them off from the wall, each of them hang- 
ing to that which had been brought to it. The 
same experiments held with the painted boards of 
the room, and likewise with the looking-glass, to 
the smooth surface of which both the white and the 
black silk appeared to adhere more tenaciously than 
to either of the former. 
Similar experiments, but with a greater variety 
of circumstances, were afterwards made by Mr 
Cigna of Turin, upon white and black ribands. 
He took two white silk ribands just dried at the fire, 
and extended them upon a smooth plane, whether 
a conducting or electric substance was a matter of 
indifference. He then drew over them the sharp 
edge of an ivory ruler, and found that both ribands 
had acquired electricity enough to adhere to the 
plane ; though, while they continued there, they 
showed no other sign of it. When taken up sepa- 
rately, they were both negatively electrified, and 
would repel each other. In their separation, electric 
sparks were perceived between them; but when 
again put on the plane, or forced together, no light 
was perceived without another friction. When, by 
