C'<5] 
When I apply ’d the Tube to the other Feather that 
hung by the Thread, (which, like mod vegetable Sub- 
ftances, is generally Non eleCtric per fe\ the Feather 
was conftantly attracted, and never repell’d , becaufe 
the Virtue communicated from the Tube to the Fea- 
ther, loft itfelf along the Thread 5 which would have 
been retain’d by the Feather, if it had floated in dry 
Air, or been fufpended by an EleCtrical Body. 
Thefe Properties of EleCtric Bodies fhew the Rea- 
fon of that ‘Phenomenon , whereby a rubb’d Tube, 
after having attracted a Feather, repels and chafes it 
about a Room in the Air, and does not attract it a 
fccond time, till the Feather has touch’d fome other 
Bodyj and alfo (hews the Reafon why the Experi- 
ment does not fucceed in moift Weather. 
Pure Air, that is dry, may be rank’d among the 
EleCtrics per fe, becaufe it repels all Bodies in a State 
of Electricity, whether they have been excited to it 
by Wax or Glafs; that is, by either of the two forts 
of Electricity. 
Watery Vapours, that float in the Air, are Non- 
electric 5 from which Mixture the Air becomes more 
languid in its ElcCtricity, when moft impregnated 
with Vapours ; fo that dry Air is more ElcCtric than 
moift ; but cold Air in frofty Weather, when Va- 
pours rife lead of all, is more eleCtric than Air in 
Summer, when the Heat raifes Vapours 5 which renders 
that State of the Air more fit for making EleCtrical 
Experiments. 
The rubb’d Tube retains its ElcCtricity a long time, 
becaufe it repels, and is repell’d by, the dry Air; and 
the Feather, which has been attracted by the Tube, after 
adhering to it a while, is rais’d out of its languid 
State 
