_Pass an excited glass tube near the other end of the prime
conductor, so as to give it some sparks, and the threads will
diverge._
Because each thread, as well as the prime conductor, has acquired an
electric atmosphere, which repels and is repelled by the atmospheres
of the other threads: if those several atmospheres would readily mix,
the threads might unite, and hang in the middle of one atmosphere,
common to them all.
_Rub the tube afresh, and approach the prime conductor therewith,
crossways, near that end, but not nigh enough to give sparks; and
the threads will diverge a little more._
Because the atmosphere of the prime conductor is pressed by the
atmosphere of the excited tube, and driven towards the end where the
threads are, by which each thread acquires more atmosphere.
_Withdraw the tube, and they will close as much._
They close as much, and no more; because the atmosphere of the glass
tube not having mixed with the atmosphere of the prime conductor, is
withdrawn intire, having made no addition to, or diminution from it.
_Bring the excited tube under the tuft of threads, and they will
close a little._
They close, because the atmosphere of the glass tube repels their
atmospheres, and drives part of them back on the prime conductor.
_Withdraw it, and they will diverge as much._
For the portion of atmosphere which they had lost, returns to them
again.