480 Memoir on Sulphuric Ether. 
require 6 atoms of oxygen, weighing 42, for 
their combustion; that is, such compound 
atom would require rather more than double 
its weight of oxygen, which is the propor- 
tion I find by experiment for ether va- 
pour. Hence then we may conclude, that the: 
atom of ether weighs 20.8, and is compounded 
of 1 atom of water and 2 of olefiant gas. 
In January 1809, [ made an experiment 
on the slow combustion of ether in a lamp, - 
in a large balloon glass. The capacity of 
the balloon was 2 cubic feet ; hence the oxy- 
gen of the common air in it would weigh 250 
grains, nearly.—A small lamp with ether 
was lighted and instantly dropped into the 
balloon, which was immediately closed. The 
lamp burned till it was extinguished for want 
of air. After a few minutes it was taken 
out, and the loss of weight ascertained to be 
31 grains. The residuary gas being examined, 
was found to contain 16 per cent. oxygen, 
and 3 or 4 carbonic acid; but in order to ob- 
tain the carbonic acid more accurately, the 
whole volume of air was subjected to lime 
water, in such manner, thatall the air which 
caine out was agitated in the lime water that 
entered the balloon. The quantity of lime 
water requisite to saturate the carbonic acid, 
was as much as saturated 107 grains in weight 
