464. Memoir on Sulphuric Ether. 
through the neck of the bottle up to the sur 
face of the mercury in the bottle. In this 
way the ether was conveyed through the mer- 
cury without quitting the tube, and by gentle 
agitation was ejected and dissipated in vapour 
in a few minutes afterwards. 'The results in 
several experiments were nearly uniform, giv- 
ing an increase of volume of gas from 255 to 
275 grain measures for each grain of ether 
in weight. This gives the specific gravity of 
ether vapour from 3.1 to 3.3. On the whole, 
I think 3.1 is probably the nearest expression 
in two places of figures that can be at- 
tained. 
Elasticity of Ether Vapour, the same in Air 
and in a Vacuum. 
The same tension or elasticity of ether 
vapour takes place in air as in a vacuum, just 
as with the steam of water and other liquids. 
But this is not true of impure ether if it be 
made to pass through water into the air, be- 
cause by this operation it is improved in 
quality, though greatly diminished in aie 
tity. 
When the tcinpcranaie of the air was 43° 
and barometer 29.70, I passsed up through 
