CHAPTER IV. 



THK FUSING POINT. 



The very gradual and almost imperceptible manner in which, 

 fats, particularly butter, begin to soften, melt, and liquefy on 

 the application of heat, renders it difficult to fix the point of 

 actual fusion. 



"We employ the term " fusing point " with some reserve. 

 Most fats, if not aU, are mixtures of different glycerides, 

 amongst which olein is rarely absent. This glyceride, pos- 

 sessing the power of dissolving considerable quantities of 

 palmitin or stearin even at ordinary, and doubtless far larger 

 amounts at elevated, temperatures, plays the same part in soft . 

 fats as does water ia saline solutions. It takes up on heating 

 the glycerides which are mixed with it, and as soon as the 

 mass is clear, it is termed " fused," although, properly speak- 

 ing, it ought to be called a perfect solution. Hence it is 

 obvious that the so-caUed fusing point is not a sharp, decided 

 phenomenon. 



Experience has taught all those who have worked upon 

 butter analysis, that the fusing point — to take which so many 

 methods have been devised — :is, after all, of little value in 

 affording an indication as to the genuineness or otherwise of 

 a given sample of butter. Mixtures of solid and liquid fats 

 can very easily be prepared, having the normal melting point 



