412 On the Properties of a Mixture of Liquids. 



In the same way as in the preceding section, we may 

 calculate the value of 7r B /7r A . For benzene and ethyl acetate 

 we have 



78 — 

 logWB/7r A = -038 x log ~ -1-978 = '020. 



oo 



To compare with this we have as the vapour-pressure of 

 benzene at 50° according to S. Young 269 milliin., or 

 Regnault 271 millim.; while from 0. Schumann's observa- 

 tions (Wied. Ann. xii. p. 47) that of ethyl acetate is 284 



millim. Now log |H = -0235, log ||| = 0203. 



Similarly for benzene and methyl acetate 



log V r A=-081og^|-T705=-297, 



and Schumann's experiments give tt b (for methyl acetate) 

 = 588 millim. 



L ° g 269 = ' 3396 > and lo &' 27l = ' 3364, 



The discrepancy in this case is more serious than in the other 

 two. 



For the further testing of the theory, some preliminary 

 experiments on the vapour-pressure of mixtures of the liquids 

 used have been carried out. They, together with the results 

 detailed above, seem to indicate that while the theory of the 

 present memoir may serve as a useful introduction to this 

 almost untouched subject, it will require emendation before 

 representing the facts with the degree of accuracy attainable 

 in the experiments themselves. Probably the weakest point 

 of the theory lies in the assumption that the vapours obey 

 Boyle's law up to the moment of condensation, and better 

 agreement may be looked for when allowance is made for the 

 greater density of the nearly saturated vapour, in calculating 

 the thermodynamic potential. I hope to be able to continue 

 the research along the lines here indicated, both of theory 

 and experiment. 



The experimental part of this research was carried out in 

 the laboratory of Prof. Ostwald, at Leipzig, and it gives me 

 much pleasure to express my thanks to him and to Dr. Le 

 Blanc for the many valuable suggestions as to methods, and 

 other assistance for which 1 am indebted to them. 



