Memoir on Sulphuric Ether. 465 
water into a graduated tube containing 51 
grain measures of air, about 3 or 4 grains of 
-73 ether. The air was in a few minutes ex- 
panded to 74 measures ; and the ether baro- 
meter (that is, a barometer with the same 
kind of ether thrown up into the vacuum) 
stood at 20.5 in the same temperature; hence 
29.7 , 
we have 55x ar ox 51)=74 nearly ; which 
accords with the beforementioned theorem. 
The tube being afterwards immersed in water 
of 66°, gave 104 measures of vapourized 
gas; and in 70° gave 118 measures.—It 
stood for some months in water, still retain- 
ing a fluctuating volume of gas, according 
to the changes of barometer and thermo- 
meter; andat last the gas was passed through 
water, and instantly gave the original 51 mea- 
sures of air. 
The quality of ether may be judged of 
from passing a small portion of it through 
water in a graduated tube. Thirty grain 
measures of the best ether (.73), passed up a 
tube of 8 inches long filled with water, lost 
4or 5 grains. Thirty grains of another 
ether, consisting of a mixture of 15 ether 
(.735) and 15 alcohol, (.85) when passed in 
like manner, only gave 5 measures of fluid 
ether, swimming on the surface of the water. 
VOL. III. Nnn 
