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which I threw out a hint in my third paper, and 
which I have iince taken an opportunity of making, 
touching the electrical cohefion of glafs. The experi- 
ment is as follows : 
I took two panes of common window-glafs, about 
nine inches fquare, the thinned, the molt even, and 
the fmootheft in their furfaces I could get. I covered 
one of the fides of each with tin-foil, leaving the fpace 
of near an inch from the edges uncovered. I warmed 
them a little at the fire ; and, applying the two bare 
tides together, I laid them upon four wine-glades, 
which lupported them at the corners. I then brought 
dowm a chain from the prime conductor, nearly to 
touch the coating of the upper plate, and applying a 
wire, which I held in my hand, to the coating of the 
under plate, the machine was put in motion, and the 
electrification performed, as in the cafe of the com- 
mon eleCtrical pane. When the operation was com- 
pleted, I removed the chain and the wire, and taking 
hold of twooppofite corners of the upper glafs (thofe 
correfponding to them in the other having been pur- 
pofely cut away, I lifted it, and found, that the un- 
der glafs came up with it. The cohefion appeared to 
me to be confiderably ftrong ; but I had not any pro- 
per apparatus ready to meafure the ftrength of it. 1 laid 
them down again on the wine-glaffes, and procured 
an explofion, as in the cafe of the common eleCtrical 
pane. I then took hold of the corners of the upper 
glafs, and lifted it ; but found, that the cohefion was 
diffolved, the under glafs remaining behind. 
I could indeed perceive, that, after the difcharge, 
there was fiill fome fmall degree of cohefion between 
the pfates, which felt as if fome glutinous fubftance 
had; 
