C pj ) 
Form’d by a rubb’d Glafs Tube, or by Amber ^ and if the 
Threads were plac’d in a Bottle well cork’d up, or any 
other clofe Glafs, I fuppofe it would anfwer the fame. 
This Difcovery was made this day, being the 23d of 
ffine, 1708. and I doubt not but to carry it farther than 
what I here now give an Account of. 
f t 
F 0 S T S C R I P T. 
r have fince repeated this Experiment with Leaf-Brafs 
cover’d with a Glafs Difh on a Table, and it was obier- 
vable, that (alcho’ the Diih was very thick; upon hold- 
ing the well rubb’d Sealing Wax over it, the Pieces of. 
Leaf-Brafs wdthin v'ouid have a brisk Motion given them, 
and continue fo a confiderable time, ere ihe Wax would 
require any frelh Attrition. But this Appearance will 
not always fucceed ^ for fome time after erdeavouring 
the fame Experiment, i could by no means make it an- 
fwcr as betore rThe Temperature of the Air being then 
alter’d, its moift Effiavia vvere condens’d on the Glafs 5- 
and fo long as it remain’d under fuch Circumftance, it 
v^as attempting it in vain. But I found, that if theGlafs: 
was a little warm’d by the Fire, or plac’d a while in the 
Sunlhine, or well rub’d with a warm dry Linnen Cloath, 
any of which, whereby the Humid might be eva- 
porated, that then the included Pieces of Leaf-Brafs^ 
would, from the affricated Wax', have as brisk a Motion 
given them as before. Now, whether the Fire, Sunlhine, 
or the rubbing the Glafs with a warm dry Linnen Cloath, 
not only clears it from the moift Efflnviu condens'd on ir, 
but likewife gives motion to the Particles of the Glafs hi 
felf : Which Motion Ferns to produce Effinvia, which 
in conjundtion with that of the Sealing-Wax, facilitates 
its Adfion on the premention’d Bodies^ and that it does 
fo 
