126 EXPERIMENT STATION. [Jan. 



from the ether (e) and saponification (s) numbers by means of 



the formula? : — „ 



n = 5 (3) 



1— .0002257 e 



56158 ... 



m = (4) 



n 



Mean Molecular Weight of Fatty Acids in Neutral Fat. — 

 The molecular weight (m) of the acids in the neutral fat can 

 be calculated from the ether number (e) and the percentage of 

 neutral fat (F) — determined either gravimetrically or by dif- 

 ference ^ — by the formula : — 



3X5615.SXF 16S474F 



m = ^ — — or 



e e 



m = 3(m- H) + C3H5 or 3(m— 1 008) + 41 .04 or 



168474 F 3 m + 38.016 



3 m + 38.016 = 



e 



56158 F ^.^ „-^T ._. 

 m = 12.672 (5) 



Fatty Acids in Neutral Fat. — The fatty acids (IST) in neu- 

 tral fat can be calculated from the percentage of neutral fat 

 (F) and the mean molecular weight (m) of the fatty acids in 

 the neutral fat : ^ — o 



3 m + C3li2 



The total fatty acids are equal to the sum of the fatty acids in 

 the neutral fat and the free fatty acids. 



Glycerol. — The glycerol (G) can be calculated in a manner 

 similar to the fatty acids in the neutral fat. 



(._p _92,064__ 

 3 m + 38.016 



Free Fatty Acids. — The acid number (a) can be readily con- 

 verted into percentage of free fatty acids (A) expressed as oleic, 



1 The unsaponifiable matter is a source of error. 



- A close approximation can usually be obtained by using the mean molecular weight of 

 the total fatty acids. 



