Mr GRAHAM'S Account of the Formation of Akoates. 185 



tion crystallizes readily when farther concentrated. A solution 

 saturated at 170, and which consisted of 10 parts alcohol and 7 

 parts chloride of calcium, or nearly the atomic proportions of the 

 alcoate, crystallized slowly upon cooling, forming crystals upon 

 the surface of the liquid and sides of the phial, of great regularity 

 and beauty. The whole crystallized during a cold night, leaving 

 no mother liquor whatever. 



The injurious effect of the presence of water, in the forma- 

 tion of this alcoate, was evident in alcohol of the specific gravity 

 0.798, in which the contaminating water did not amount to 1 

 per cent. A solution of chloride of calcium in alcohol of this 

 strength did not crystallize readily, and the crystals eventually 

 deposited were small and ill formed. Chloride of calcium does 

 not crystallize at all in alcohol of the specific gravity 0.827. The 

 same inconvenience arises from employing chloride of calcium 

 containing a little water. 



Although the alcoate of chloride of calcium in a state of pu- 

 rity is entirely decomposed at a temperature not exceeding 250, 

 yet, when water is present, alcohol can be retained by the chlo- 

 ride of calcium at a much higher temperature. Thus I repeat- 

 edly found, that chloride of calcium, from which alcohol had 

 been rectified, and which afterwards had been washed out the 

 retort by water, gave indications of the presence of alcohol, after 

 being exposed on the sand-bath to a heat of 400 or 500 for 

 several hours. Transferred in a crucible to the fire, after it 

 ceased to lose weight on the sand-bath, alcohol-vapour was emit- 

 ted, which took fire and burned. 



2. Alcoate of Nitrate of Magnesia. 



It is difficult to expel the whole of the water with which ni- 

 trate of magnesia is combined, without driving off a portion of 



VOL. XI. PART I. A a 



