1 24 Mr. Drinkvvater on the Preparation of 



quicklime and the same alcohol mixed with it; the mixture 

 was then allowed to digest a \\hole week at the ordinaiy tem- 

 perature of the laboratory, about 60" F. After this time the 

 alcohol was distilled off as before, but was redistilled very 

 slowly, at first at the rate of about one drop in ten seconds 

 (heat of water-bath 165° F.) ; this was continued till about 

 one-twentieth of the whole had distilled over, the object being 

 to allow any minute quantity of water which the alcohol 

 might still retain to evaporate or diffuse itself into the atmo- 

 sphere of absolute alcohol above it ; the redistillation was 

 then contmued rapidly, the heat of the bath being increased 

 to 180° F. till about one-twentieth more had passed over; 

 the receiver was then changed and the remaining part slowly 

 distilled off. 



The specific gravity of this alcohol taken twice was '7944 

 at 60° F. As a further test of its purity it was divided into 

 two equal parts ; one part was again digested on quicklime, 

 and the other on sulphate of copper deprived of water by 

 heat, the method of operation being as follows : — 



1st. Some lumps of fresh-burnt quickhme were heated to 

 a red heat, and in that state quickly pulverized and intro- 

 duced into the tin boiler of a small still, which was partly 

 immersed in water to prevent the melting of the solder. 



This vessel was completely filled with quicklime, and was 

 kept corked till suflficiently cool, when the alcohol was added, 

 but it being comparatively small in quantity the lime ap- 

 peared perfectly dry ; the vessel was then securely corked. 



2nd. A quantity of sulphate of copper was exposed to a 

 red heat till completely deprived of water ; it was then quickly 

 pulverized and introduced into a small tin boiler, and when 

 cold the alcohol (which was insufficient to cover it) was added, 

 and the vessel closely corked. 



These vessels with their contents were kept at the ordi- 

 nary temperature of the laboratory (about 60° F.) for four 

 days ; they were then partly immersed in a water-bath, and 

 kept at a temperature of about 150° F. for forty-eight hours, 

 after which the alcohol was distilled and redistilled with all the 

 precautions before- mentioned ; the temperature of the water- 

 bath on the redistillation never exceeded 172° F., and the 

 first tenth joart was put aside in each case as possibly impure. 



The specific gravities of the alcohol thus obtained were as 

 under : — 



