From Water and other Liquids, ce. 565 
ihe temperature of the air in the room, 62°, the 
mercury stood at 17. 00 inches, the barometer 
at the same time being 29. 75. Hence the force 
of vapour from ether at 62°is equal to 12. 15 
inches of mercury, which accords with the force 
of aqueous vapour at 172°, temperatures which 
are 40° from the respective boiling points of the 
liquids. By subsequent observations I found the 
forces of the vapour from ether in all the diffe. 
rent temperatures from 32° to 102° exactly cor- 
responded with the forces of aqueous vapour of 
the like range, namely from 142° to 212°: the 
vapour from ether depresses the mercury about 
6 inches in the temperature of g2°. 
Finding that ether below the point of ebullition 
agreed with water below the said point, I naturally 
concluded that ether above the point would give 
the same force of vapour as water above it; and 
in this I was not disappointed ; for, upon trial 
it appeared that what I had inferred only from 
analogical reasoning respecting the force of aque- 
ous vapour above the boiling poinr, actually 
happened with that from ether above the said 
point. And ether isa much better subject for 
experiment in this case than water, because it 
does not require so high a temperature.’ 
I took a barometer tube of 45 inches in length, 
and having sealed it hermetically at one end, 
bent it into a syphon shape, making the legs pa- 
