EXAMINATION OF FATS. 



1413 



If determined at room temperature, the following formula may be 

 used to calculate the specific gravity at 15.5: a 



G=G'+.00064 (T-15.5). 

 G=sp. gr. at 15.5. 

 G'=sp. gr. at T. 

 0.00064=mean correction for 1 C. 



This is only approximately correct, as the correction varies for dif- 

 ferent oils, but will satisfy ordinary requirements. If a higher degree 

 of accuracy is desired, the factors given in the following table may be 

 employed, but to obtain the best results the determination must be 

 made at standard temperature. 



Factors for calculating specific gravity. b 



The following table gives correction for solid fats.' 



Factors for calculating specific gravity. 



DETERMINATION AT THE TEMPERATURE OF BOILING WATER. d 



STANDARDIZATION OF FLASKS. 



First method. Use a small specific gravity flask of from 25 to 30 cc 

 capacity. The flask is to be thoroughly washed with hot water, 

 alcohol, and ether, and then dried. After cooling in a desiccator, the 

 weight of the flask and stopper is accurately determined. 



a Allen, Com. Org. Anal., 3d ed., vol. 2, pt. 1, p. 33; Winton, Conn. Expt. Sta. 

 Kept., pt. 2, 1900, p. 149. 



b Allen, Com. Org. Anal., 3d. ed., vol. 2, pt. 1, p. 33. 

 c Allen, Com. Org. Anal., 3d ed., vol. 2, pt. 1, p. 32. 

 d U. S. Dept. Agr., Div. Chem. Bui. 46, revised, p. 51. 



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