16 



plate. Dissolve the dry soap in a liter of boiling water, and if alcohol has been used 

 boil for forty minutes in order to remove it, adding sufficient water to replace that 

 lost in boiling. Add 100 cc of 30 per cent sulphuric acid (25 Baume sulphuric acid) 

 to free the fatty acids, and boil until they form a clear, transparent layer. Collect 

 the fatty acids in a small beaker and place on the steam bath until the water has 

 settled, then decant them into a dry beaker, filter, using a hot-water funnel, and 

 dry twenty minutes at 100 C. When dried, cool the fatty acids to 15 C. or 20 C. 

 above the expected titer and transfer to the titer tube, which is 25 mm in diameter 

 and 100 mm in length (1 by 4 inches) and made of glass about 1 mm in thickness. 

 This is placed in a 16-ounce, salt-mouth bottle of clear glass, about 70 mm in diam- 

 eter and 150 mm high (2i by 6 inches) , fitted with a cork, which is perforated so 

 as to hold the tube rigidly when in position. The thermometer, graduated to 0.1 

 C., is suspended so that it can be used as a stirrer, and the mass is stirred slowly 

 until the mercury remains stationary for thirty seconds. The thermometer is then 

 allowed to hang quietly, with the bulb in the center of the mass, and the rise of the 

 mercury observed. The highest point to which it rises is taken as the titer of the 

 fatty acids. 



The fatty acids are tested for complete saponification as follows: 

 Three cc of the fatty acids are placed in a test tube and 15 cc of alcohol (95 per 

 cent by volume) added. The mixture is brought to a boil and an equal volume of 

 ammonia (0.96 sp. gr. ) added. A clear solution should result, turbidity indicating 

 unsaponified fat. The room temperature must be reported. 



The referee had 4 a thermometer made which removes some of the 

 difficulties. It is graduated in one-tenth degrees from 25 C. to 60 C.,' 

 and has a bulb which allows the temperature to rise much higher with- 

 out injury to the thermometer. This instrument can always be 

 immersed in the fat to a definite point, and thus the error due to the 

 rising of the mercury column above the liquid will always be the same* 



L. M. TOLMAN, 



Associate Referee on Fats and Oils. 



Recommended for publication. 

 H. W. WILEY, 



Chief of Bureau and Secretary A. 0. A. C. 



Publication authorized. 

 JAMES WILSON, 



Secretary. 



WASHINGTON, D. C., January 3, 1905. 



