— 156 — 



3. "On new methods for the separation of mixtr.res of liquids of which 

 the boiling-points are the same, or lie close together 1 )." This paper is 

 the first of a series of articles which apparently treats the subjects just 

 referred to in greater detail. We intend to deal with this matter when 

 the series is completed. 



4. "On fractional distillation with steam 2 )." A. Golodetz has carried 

 out several distilling-experiments with the object of discovering whether 

 it is easier to separate a mixture of liquids with different degrees of vola- 

 tility by means of distillation with water or by dry distillation. He ob- 

 tained the following results: — 



"a) Fractional distillation of mixtures of substances insoluble in water, 

 and water (provided the b. p. be not too high), gives excellent results, 

 much better than those obtained by ordinary distillation under similar 

 conditions. 



b) The distillation of mixtures of high b. p. gives less satisfactory results, 

 but when high rectifying apparatus is employed, distillation with water 

 also answers very well in this case. 



c) In the course of the rectification-process the mixture distilled with 

 water undergoes certain changes consisting in the simultaneous alter- 

 ation of temperature and pressure, which changes proceed in different 

 directions. 



d) The process of distillation is completely governed by Young's law, 

 according to which the quantity of liquid which has been distilled off 

 in the presence of water up to the mean of the difference in tem- 

 perature between the boiling-points of each component part, equals 

 in quantity the whole of the first component, plus the corresponding 

 quantity of water. 



e) The result of the fractionation depends upon the difference between 

 the boiling points of the individual components with water, and upon 

 the quality of the rectifying apparatus." 



Apart from conclusions b and d, the other statements are incorrect. 

 The author has made too light of his task. He makes two experiments 

 in fractionation with a mixture of benzene-toluene and water, and then 

 compares the results of this distillation with water with the results of an 

 experiment in dry distillation made by another author. The separation in 

 the said author's experiment having given less favourable results than in 

 his own, Golodetz concludes that fractionation of the oil-mixture witiv 

 water is the better method. In arriving at this conclusion, he happerri 

 to have hit upon a rather poor experiment in separation among those 

 recorded in literature. Thus, for example, Young's distilling-experiments 3 ) 



« 



*) Chem. Ztg. 36 (1912), 273, 297. 



2 ) Zeitschr. f. physik. Chem. 78 (1912), 641. 



3 ) Fractional Distillation, London 1903, p. 174. 



