18. MELTING POINTS OF FAT ACIDS. 17 



Heintz also noticed that a mixture of three fat-acids could melt 

 at a still lower temperature, even if the third fat-acid added 

 possessed a higher melting-point than either of the others. A 

 mixture of 30 parts of palmitic and 70 of myristic acid melts at 

 46 "2°, and solidifies amorphous. To 20 parts of this mixture 

 stearic acid was added in the following proportions, and melting- 

 point and manner of solidification observed : 



To 20 parts of a mixture of 30 parts of myristic with 70 of lauric 

 acid, melting at 35 'l", palmitic acid was added, and the following 

 observations made : 



These tables show clearly that it is important to examine the 

 fractions in the succession in which they w^ere prepared. For 

 instance, supposing the first precipitate to have yielded a fat- 

 acid melting at 68°, which might consequently be considered as 

 stearic acid, the following precipitates fat-acids melting at about 



9 



