qe ee, a 
Memoir on Sulphuric Ether. 459 
specific gravity of this vapour, as it was 
sufficient to have 4 or 5 per cent. of volume 
of it to produce abundance of carbonic acid 
and to require a greater abundance of oxygen, 
I found it expedient to ascertain as near as 
possible the exact specific gravity, and at- 
tempted it as follows, in September 1803. 
I took ‘a balloon glass, of the capacity of 
253 cubic inches, having a wide neck, to 
which was adapted a brass cap and stopcock. 
Into this a graduated tube, 3, of an inch dia- 
meter, containing ether of .758 specific gra- 
vity, and a manometer were introduced ;. the 
manometer was as usual a tube of 4, inch bore, 
closed at one end and duly graduated, with a 
globule of mercury sliding in it. The vessel 
was immediately made air tight, and kept so 
for several days, during which time the pro- 
gress of the evaporation and of the gage was 
occasionally noted. The temperature of the 
air in the room was usually about 55° ; but as 
this was of no importance, it was not particu- 
larly noted.—The observations follow :—the 
ether tube was graduated into water grain 
measures ; barometer 30 inches. 
