BUTTER. 67 



more exact. The following reagents are required. 



Glyceifol Soda. — lOO grams of pure sodium hydrox- 

 id are dissolved in lOO c. c. of distilled water, and al- 

 lowed to stand until clear. 20 c. c. of this solution are 

 mixed with 180 c. c. of pure concentrated glycerol. 

 The mixture may be conveniently kept in a capped bot- 

 tle holding a 10 c. c. pipette. 



Sulfuric Acid. — 20 c. c. of pure concentrated sulfuric 

 acid, made up with distilled water to 100 c. c. 



Barium Hydroxid. — An approximately decinormal, 

 accurately standardized, solution of barium hydroxid. 



Indicator. — An alcoholic solution of phenolphtha- 

 lein. 



About 50 grams of the sample are placed in a 

 beaker, and heated to a temperature of 120° to I40°F, 

 until the water and curd have settled to the bottom. 

 The clear fat is then poured on a warm dry plaited fil- 

 ter, and kept in a warm place until 25 or 30 c. c. have 

 been collected. If the filtrate is not perfectly clear, it 

 should be reheated for a short time and again filtered. 



A 300 c. c. flask is washed thoroughly, rinsed with 

 alcohol and then with ether, and thoroughly dried by 

 heating in the water oven. After cooling, it is allowed 

 to stand for about 15 minutes and weighed. A pipette, 

 graduated to 5.75 c. c, is heated to about I40°F and 

 filled to the mark with the well mixed fat, which is 

 then run into the flask. After standing for about fif- 

 teen minutes, the flask and contents are weighed. 20 c.c. 

 of the glycerol soda are added and the flask heated 

 over the Bunsen burner. The mixture may foam 



