320 



BUTTEE. 



strengtli that 2 c.c. of caustic soda solution should neutralise 

 about 35 c.c. The apparatus should have exactly the dimensions 

 given in the figure, and the temperature of the cooling water 

 should be such that the distillate enters the flask at about 20° C. 

 The flask is heated by a small flame till the fatty acids are 

 just melted, and the flame then turned up to such a height that 

 110 c.c. of distillate are collected in from 19 to 21 minutes, when 



^Aj<y>o 



Fig. 44. — Polenake Apparatus. 



the flame is immediately removed, and the flask replaced by 

 a cylinder. 



The flask is placed for ten minutes in water at 10° C, and after 

 the physical condition of the insoluble fatty acids has been 

 noted, the contents are well mixed, filtered, and 100 c.c. are 

 titrated as in the Eeichert-Wollny process. 



The whole of the distillate is passed through the filter, and 



