[ 9i ] 
the other, rarefies the air very evidently. Which 
fhews, I think, that the eledric fire mud produce 
heat in itfelf, as well as in the air, by its rapid mo- 
tion. 
The charge of one of my glafs jars, which will 
contain about five gallons and a half, wine meafure, 
darting from wire to wire, will, by the diflurbance 
it gives the air in the explofion repelling it in all di- 
rections, raife the column in the tube K up to d , or 
thereabouts ; and the charge of the above-mentioned 
cafe of bottles will raife it to the top of the tube. 
Upon the air’s coalefcing, the column, by its gravity, 
inflantly fubfides till it is in equilibrio with the rarefied 
air ; it then gradually defcends, as the air cools, and 
fettles where it flood before. By carefully obferving 
at what height above the gage-wire b the defcending 
column firfl flops, the degree of rarefadion is difco- 
vered ; which, in great explofions, is very confiderable. 
EXP. X. 
I hung in the thermometer, upon the hook I, 
fucceflively, a flrip of wet writing paper, a wet flax- 
en and woolen thread, a blade of green grafs, a fila-^ 
ment of green wood, a fine filver thread, a very fmall 
brafs wire, and a flrip of gilt paper; and found that 
the charge of the glafs jar, pafling thro’ each of thefe, 
efpecially the lafl, produced heat enough to rarify the 
air very perceptibly. The charge of the cafe of bot- 
tles fent thro’ the brafs wire confumed great part of 
it into fmoke. The thermometer appeared quite 
opaque with it. 
O 2 
EXP. 
