266 Mr. Graham's Account of the Formation of Alcoates. 



aether, and its total abstraction converting alcohol into olefiant 

 gas ; while the supposition that the oxygen and hydrogen exist 

 in the state of water, is altogether gratuitous. 



The process of Richter is exceedingly tedious, from the 

 necessity of conducting it so slowly, and the waste of alcohol 

 is considerable. I tried newly burnt quicklime instead of 

 chloride of calcium, and distilled by the heat of a saline water- 

 bath. If it is merely our object to obtain alcohol perfectly 

 free from water^ no process could be more effectual. The 

 product was of the specific gravity 0*794 ; but it contained a 

 trace of aether, to which the extraordinary lowness of its spe- 

 cific gravity is attributable ; and had an empyreumatic odour, 

 notwithstanding the moderate temperature at which the distil- 

 lation was conducted. This likewise is a very slow process. 



The process which I preferred is founded on the principle 

 of Mr. Leslie's frigorific apparatus. The alcohol is concen- 

 trated by being placed under the receiver of an air-pump, with 

 quicklime. A large shallow basin is covered to a small depth 

 with recently burnt lime in coarse powder, and a smaller basin 

 containing three or four ounces of commercial alcohol is made 

 to rest upon the lime : the whole is placed upon the plate 

 of an air-pump, and covered over by a low receiver. Ex- 

 haustion is continued till the alcohol evinces signs of ebulli- 

 tion, but no further. Of the mingled vapours of alcohol and 

 water which now fill the receiver, the quicklime is capable of 

 combining with the aqueous vapour only, which is therefore 

 quickly withdrawn, while the alcohol -vapour is unaffected. 

 But as water, unless it has an atmosphere of its own vapour 

 above it, cannot remain in the alcohol, more aqueous vapour 

 rises. This vapour is likewise absorbed, and the process goes 

 on till the whole water in the alcohol is withdrawn. Several 

 days are always required for this purpose, and in winter a 

 longer time than in summer. The following cases exhibit the 

 rate, according to which the water is withdrawn. The first 

 experiment was made in summer. Four ounces of alcohol of 

 the specific gravity 0*827 were concentrated. The specific 

 gravity was taken every twenty-four hours, and the following 

 series of results obtained : 



0*827 



0*817 



0*808 



0*802 



0*798 



0*796 

 In this case the whole water was withdrawn in five days, but 



occasionally 



