Reilly & VLiCKmBOTTOM— Ooncentratton of Alcoholic Liquors. 235 



where a and b represent the percentage by volume of alcohol and water respec- 

 tively in the original liquid, and da and dh the percentage of alcohol and 

 water respectively in the vapour, 'J'he above relation may be represented by 

 a hyperbola. The value for c with dilute solutions of various alcohols varies 

 from 10-9 for methyl alcohol to 50 for amyl alcohol and 61 for capryl alcohol. 

 The coefficient c increases with the molecular weight of the alcohol. The 

 relation established by Duclaux has been verified for ethyl alcohol and 

 several of the higher alcohols up to the point corresponding with mixtures of 

 constant boiling point. 



Sorel,' pursuing the problem from the point of view of its industrial 

 application, carried out distillations on quantities of four litres of liquid. He 

 took precautions to prevent loss of heat by radiation, and probably it is due 

 to this fact that his results differ somewhat from those of Duclaux. Against 

 the volume distilled, Sorel plotted the composition of the remaining liquid, 

 and obtained a curve representing the rate of elimination of alcohol from the 

 aqueous solution. 



The distillation of dilute solutions can be represented approximately by 

 the expression 



Va = {V-dV){a - da) + UdV, 



or U = a + y jy., 



where 



V = volume remaining in the flask at any moment ; 



a = concentration of alcohol in the solution ; 

 11= concentration of alcohol in the distillate. 

 Mariller - uses the coefficient K, which is given by 



j^ percentage of alcohol in vapour 

 percentage of alcohol in liquid ' 



or, in the Duclaux notation (see above), = — = ~-=. 



' ^ a ac + iOO 



It is found that the coefficient K, which may be called the coefficient of 

 solution, or better, the coefficient of enrichment, is dependent on the alcoholic 

 concentration. It is found that on Sorel's formula. A' ^ 9'9 for ethyl alcohol of 

 1 per cent, concentration, and this value gradually diminishes as a increases. 

 With « = 20 K = 3'31, with a - 50 K = I'O, and, as a increases, the value of 

 K gradually falls from 1-5 to 1. Thus for a = 96, K= 1002, and for a = 97, 

 K is recorded as I'OOl, and for a = 100, K is given as 1. The last two 

 values are apparently incorrect, for it would be expected that K should 



1 Comptes rendus, 1892, 116, 093. 



- "La Distillation Fractionn^e," 1917, p. 21^ : cf. also " Le Bulletin de I'Assoc. des 

 Chimistes," 1911, p. 4-73, &c. ; and " La Distillation," p. 147. 



2l 2 



