Memoir on Sulphuric Ether. 457 
water till the vapour arose from the ether and 
depressed the mercury, which ascending in the 
other leg, was brought to a level in the two. 
In this way, the same ether, in the tempera- 
ture of 98°, exhibited a force equal to the at- 
mosphere. Something like this I find takes 
place in alcohol of .83 specific gravity. It 
boils in a phialat 176°; but ina tube, its va- 
pour is equal to the atmosphere in a tempe- 
rature of 172°. Pure ether, of .72 specific 
gravity, boils in the tube at 95 or 96°, as Gay 
Lussac has observed; but in a phial I find 
the thermometer may be raised to 98° in the 
boiling liquid. The boiling point of amixture 
of pure ether and pure alcohol may be made 
to vary from 96 to 170°; but we cannot infer 
the boiling point from a knowledge of the 
proportions of the mixture ; it isalways much 
nearer that of ether than the proportions 
would indicate. Indeed it is the same with 
alcohol and water and all similar mixtures, 
A mixture of equal parts of alcohol and wa- 
‘ter boils at 183°; whereas by the rule of 
proportion it ought to boil at 194°. A mix- 
ture of 4 parts ether and 3 parts alcohol I 
found boiled at 117° in the tube, and 122 or 
123° in theair, which by proportion should 
have boiled at 127°. It wasof specific gra- 
VOL, Il. Mmm 
