Mr GRAHAM'S Account of the Formation of Alcoates. 181 



quantity of gas is emitted at the temperature of the atmosphere, 

 even in the vacuum of an air-pump. 



From one experiment, water appears to have the power to in- 

 duce the evaporation of alcohol by absorbing its vapour, as sul- 

 phuric acid does, but much more feebly. Two cups, one con- 

 taining alcohol and the other pure water, were enclosed together 

 in a tin canister which was nearly air-tight, and set aside in a 

 quiet place for six weeks. The cups were not in contact, but a 

 little apart from each other. At the expiration of that period it 

 was found, on opening the canister, that the cup which origi- 

 nally contained pure water, now contained a mixture of water and 

 alcohol, while the alcohol remaining in the other cup was of di- 

 minished strength. Professor LESLIE informs me, that he per- 

 formed a similar experiment a considerable time ago, although 

 no account of it was published. But the absorption of alcohol- 

 vapour by water is so feeble as not to occasion a sensible reduc- 

 tion of temperature in the alcohol. 



Chloride of calcium is disqualified as an absorbent of aqueous 

 vapour in the purification of alcohol, for the same reason as sul- 

 phuric acid. I find that chloride of calcium absorbs the vapour 

 of absolute alcohol, and runs into a liquid, or it deliquesces in 

 alcohol-vapour. A small quantity of this substance was sus- 

 pended in a little capsule, at the height of two inches above a 

 quantity of absolute alcohol, in a close vessel. In the course of 

 twenty-four hours it was entirely resolved into a liquid, just as 

 if it had been suspended over water. The liquid proved to be a 

 solution of chloride of calcium in absolute alcohol. The experi- 

 ment was frequently repeated. As salts which deliquesce from 

 the absorption of aqueous vapour are always capable of forming 

 hydrates, I was led from the observation of this fact to attempt 

 the formation of analogous compounds of alcohol and salts, to 

 which I now proceed. 



