Memoir on Sulphuric Ether. 451 
acid and alcohol. By due management a 
liquid of the specific gravity .785 or .79 is 
obtained, called ether. It is the ether of the 
third quality, just mentioned, and is in fact, 
a compound of alcohol and ether chiefly, in 
proportions to be investigated hereafter. In 
this state it is usually called unverified 
ether. 
When this last liquid is redistilled by a 
moderate heat till one half has passed over, 
the liquid in the receiver is denominated rec- 
tified ether. It is usually about .75 specific 
gravity, corresponding to the second quality. 
It still consists of ether and alcohol, but with 
much less alcohol than before. There is 
great reason to believe that both the wnrec- 
tified and rectified ether, as thus prepared, 
are destitute of water, except so far as it is 
an essential element of the two liquids, ether 
and alcohol in their purest states; the sul- 
phuric acid being well able to retain ail the 
excess of water of common alcohol in the 
temperatures eeaphyes in the two distilla- 
tions. 
Ether of the first ennod or that in its 
prired state, is to be obtained from the recti- 
fied ether just mentioned. The object is to 
abstract the alcohol still remaining in the 
rectified ether, This may be done in great; 
