Mr Graham oji the Absorption of Vofpours by Liquids. 333 



5. The capacity of liquids of dissimilar composition to ab- 

 sorb the vapours of each other is also exceedingly general. 

 We may always presume with safety, that if two liquids are 

 miscible in all proportions, the more fixed liquid is capable of 

 absorbing the vapour of the more volatile liquid. Yet the 

 only instances of such absorption which have been attended to 

 are the absorption of aqueous vapour by sulphuric acid, and 

 of the same vapour by nitric acid. 



6. Alcoholand waterare miscible liquids, of which water is the 

 more fixed ; and I find water to absorb the vapour of alcohol at 

 the temperature of the atmosphere with considerable avidity. 



Sulphuric acid also absorbs alcohol vapour with avidity, as 

 was stated in a former communication. The following expe- 

 riment was performed, with the view of ascertaining the rela- 

 tive intensity with which water absorbs the vapour of alcohol, 

 and sulphuric acid the vapours of water and of alcohol. 



(1.) A small Wedgewood basin, one inch and a half in diame- 

 ter, containing 200 grains water, was supported over sulphuric 

 acid in a cylindrical vessel, and closed in. Upon opening the jar 

 after twelve hours, the water was found to have lost eleven 

 grains. {%) The acid was stirred up, and instead of the water 

 200 grains absolute alcohol were introduced into the basin, 

 and the whole closed in as before. In twelve hours the alco- 

 hol was found to have lost sixty grains, and the sulphuric acid 

 had acquired a reddish tinge. (3.) The sulphuric acid was 

 now withdrawn from the jar, and pure water substituted as the 

 absorbing liquid. The quantity of absolute alcohol in the 

 basin being again increased to 200 grains, and the lid care- 

 fully luted down, in twelve hours the alcohol lost 45 grains, 

 and the water below had acquired the taste of alcohol very 

 sensibly. The vapour of sulphuric ether is absorbed with great 

 avidity by alcohol, and with much less force by water. 



The vapour of alcohol is likewise absorbed by castor oil, 

 especially after some alcohol has been previously mixed with it, 

 although with a very feeble force. Retained over alcohol for 

 ten days 200 grains castor oil became 273 grains. Bichlo- 

 ride of mercury deliquesces in alcohol vapour, although slow- 

 ly when in hard crystals. Twenty grains of the crystals (not 

 reduced to powder,) suspended in a capsule over alcohol be- 



VOL. VIII. NO. II. APRIL 1828. Y 



