[ 3°3 ] 
tube’s atmorphere would have remained, and the 
threads continue to diverge j but they clofe on with- 
drawing the tube, becaufe the tube takes with it all 
tts own Atmofphere, and the eledlric matter, which 
had been driven out of the fubftance of the prime 
condudlor, and formed atmofpheres round the threads, 
is thereby permitted to return to its place. 
Take a /park from the prime condudior^ near the 
threads, when they are diverged as before, and they 
will clofe. 
For by fo doing you take away their atmofpheres, 
compofed of the eleilric matter driven out of the 
fubftance of the prime conducftor, as aforefaid, by 
the repellency of the atmofphere of the glafs tube. 
By taking this fpark you rob the prime conduftor of 
part of its natural quantity of tlie elecftric matter ; 
which part fo taken is not fupplied by the glafs tube, 
for when that is afterwards withdrawn, it takes with 
it its whole afmofphere, and leaves the prime con- 
dudlor eledrifed negatively, as appears by the next 
operation. 
Then withdraw the tube, and they will open again. 
For now the eledlric matter in the prime conduc- 
tor, returning to its equilibrium, or equal diffufion, 
in all parts of its fubftance, and the prime con- 
ductor having loft fome of its natural quantity, the 
threads connected with it lofe part of theirs, and 
fo are eleCtrifed negatively, and therefore repel each 
other, by Pr. III. 
Approach the prime conduAor with the tube near the 
the fame place as at firft^ and they will clofe again. 
Becaufe 
