Memoir on Sulphuric Ether. 447 
This theorem is most beautifully illustrated 
by sulphuric ether. Let a common barome- 
ter have a drop of ether let up into the va- 
cuum; it will instantly depress the mercury 
several inches, more or less according to the 
temperature. Suppose it were 10 inches, the 
barometer being 30; then # -~=1.5; that is, 
if ether be passed up into air under those cir- 
cumstances, it will in due time increase the 
volume of air 50 per cent. 
For six years after this I was occasionally 
engaged in the further investigation of the 
nature and properties of ether, in which se- 
veral additional facts, and some corrections 
of those antecedently announced, occurred. 
The combustion of ether was effected in va- 
rious ways, as well asits analysis, by heat and 
by electricity. 
During all this time I procured my ether 
in small quantities at a time, and of various 
druggists as suited my convenience. Once or 
twice I ascertained the specific gravity of the 
article to be at or near.75; and I never found 
reason to suspect there was much difference 
in the specimens. Occasionally when great 
partof the ether was evaporated by time and 
neglect, I found a few drops at the bottom 
of the phial, which did not possess the pro- 
