JOURNAL 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. II, FEBRUARY 19, 1912 No. 4 



PHYSICS. — The density and thermal expansion of ethyl alcohol 

 and its mixtures with water. N. S. Osborne, E. C. McKelvy 

 and H. W. Bearce. Communicated by L. A. Fischer. To 

 appear in the Bulletin of the Bureau of Standards. 1912. 



Part I. The preparation of pure ethyl alcohol. E. C. McKelvy. 

 Ethyl alcohols from different sources were subjected to purifica- 

 tion treatments. The lower boiling impurities were completely 

 removed by heating the alcohol for a considerable time under a 

 reflux condenser, the water of which was held at about 60° C. 

 Dehydration was accomplished by means of lime, aluminium 

 amalgam, and metallic calcium, giving an alcohol of nearly identi- 

 cal physical properties. The first two gave equally good results. 

 The density values obtained with metallic calcium were somewhat 

 higher. The physical properties used as criteria of purity were 

 the density and the critical solution' temperature of alcohol- 

 kerosene mixtures (Crismer). These two methods are of approx- 

 imately equal sensitiveness. An alcohol was obtained which 

 when subjected to an additional dehydration and fractionation 

 gave alcohol of the same density and with no separation into 

 fractions of different densities. Dehydration and subsequent 

 fractionation under reduced pressure gave alcohol of essentially 

 the same density. These results indicate that the alcohol was 

 pure within the limits set by the accuracy of determination of the 

 physical constants used as criteria of purity. Dissolved acetic 

 aldehyde increased the density while ethyl ether and air decreased 

 it. 



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