140 Scientific Proceedings, Rnijal Dublin Society. 



200 c.c. of the phenolic solution were distilled in a round-bottomed flask, 

 heated on an electric hot plate, and surrounded by a steam-jacket, the usual 

 precautions being taken to ensure regular ebullition, and to prevent access of 

 cooling draughts. The distillate was collected in weighed stoppered cylinders, 

 approximately 10 grams of distillate being collected in each fraction. The 

 exact weight was obtained in each case by weighing the full cylinders. For 

 the estimation of the plienolic substances in each fraction the distillate was 

 diluted to a suitable concentration, and the estimation carried out as described 

 above. 



The values logio (cresol left in flask) were plotted against logio (volume 

 left in flask). The points obtained fell along a straight line. Then the 

 value of ji, the distillation constant, is given by the slope of the line 

 joining the points determined experimentally. See fig. 2. 



The following distillation constants were determined : — 



Comparative Distillations in Steam of Acids from Butter and other Products. 



As well as using the method of steam distillation for the analysis and 

 detection of mixtures of lower fatty acids, it may be applied to detect the 

 presence of acids of comparatively low molecular weight in the presence of 

 higher fatty acids. 



Butter differs from most other fats in containing a relatively high per- 

 centage of butyric acid. The distillation constant of the volatile fatty acids 

 from butter will, therefore, show a lower distillation constant than those 

 from other fats. On this fact a process has been worked out by which 

 butter-fat may be distinguished from other fats. 



The Eeichert-Meissl determination was carried out in the usual way, 

 collecting 110 c.c. of distillation. 100 c.c of the filtered distillate were 

 titrated with a standard barium hydroxide solution to determine the concentra- 

 tion of acid in the distillate. The barium was precipitated by the addition of 

 the calculated amount of sulphuric acid, and the solution made up to 200 c c. 

 It was distilled in an ordinary round-bottomed flask, using a steam-jacket, 

 and the distillate collected in 10-gram fractions, and titrated. The per- 

 centage of acid distilling in each fraction was calculated on the acid present 

 in 100 c.c. of the original Eeichert-Meissl distillate. 



