ELECTRICAL PROPERTIES OF SILK. 169 
any part of the apparatus. A dense stream of 
electricity appeared between the rod and the silk, 
and the conductor gave very many sparks. 
5. The knob of a jar being substituted in the 
place of the metallic rod, it became charged nega- 
tively. 
6. The silk alone, with a piece of tinfoil applied 
behind it, afforded much electricity, though less 
than when the cushion was applied with a light 
pressure. The hand being applied to the silk as a 
cushion, produced a degree of excitation seldom 
equalled by any other cushion. 
7. The edge of the hand answered as well as the 
palm, 
8. When the excitation by a cushion was weak, 
a line of light appeared at the anterior part of the 
cushion, and the silk was strongly disposed to re- 
ceive electricity from any uninsulated conductor. 
These appearances did not obtain when the excita- 
tion was by any means made very strong. 
9. A thick silk, or two or more folds of silk, ex- 
cited worse than a single very thin flap. The silk 
used was that which the milliners call Persian, 
10. When the silk was separated from the cylinder, 
sparks passed between them ; the silk was found to 
be in a weak negative, and the cylinder in a posi- 
tive state. 
The foregoing experiments show that the office 
VOL. III. M 
