REPORT OF THE CHEMIST. 



59' 



It appears from the table that the saturation equivalent is an almost 

 certain test of pure butter. Its range in the analyses made is from 

 249.5 to 230.8, while in the oleomargarine it rises to 2S-1.7. 



MANIPULATION. 



The dried and filtered butter fat is weighed in a small beaker with a 

 2 c. c. pipette. Five stout half-pint clear glass beer bottles with patent 

 rubber stopper are provided. Into three of these two c. c.s of the 

 incited fat (35°) are run, the beaker and pipette being weighed each 

 time, so as to secure the exact weight of fat taken. Into each of the five 

 bottles are now ru'i 25 c. c. of the alcoholic potash solution. The bot- 

 tles are then stoppered and placed on steam bath, being shaken every 

 five minutes until the fats are saponified. When the bottles are nearly 

 cool they are opened, and 1 c. c. phenolphthalein solution (e. g. to 250 

 c. c. alcohol) run in. 



They are now titrated with semi-normal hydrochloric acid until neu- 

 tral. The two blanks give the strength of the alkali solution, and the 

 three bottles of fats show how much of the alkali had been neutralized 

 in saponification. The following table shows the results of this process 

 in the butters already analyzed : 



Triplicate and duplicate determination. 





Saturation coefficient. 



No. 











1. 







3. 



Mean. 



1 



215.0 



245.3 



244.7 



245.0 



M 



244. 9 



245.0 



244.9 



244.9 



8 



245. 3 



244.6 



244.6 



244.8 



24 



284.6 



284.8 



284 7 



284.7 



4 



245.9 



246.3 





246.1 



6 



247.2 



247.0 





247.1 



7 



246.5 



246.3 





246.4 



14 



247.1 



246.4 





246.7 



15 



245.6 



244.8 





245.2 



16 



244.6 



244.2 





244.4 



17 



243.7 



244.1 





243.9 



18 



244.4 



244.1 





244. 2 



19 



249.2 



248.7 





24*9 



20 



283.8 



284.1 





283.9 



21 



282.4 



282.6 





282.5 



23 



280.0 



280.0 





280. 



SOLUBLE AND INSOLUBLE FAT ACIDS. 



The best proof of a pure or adulterated butter is in the relative pro- 

 portion of soluble and insoluble acids which it contains. A first-class 

 butter fat may have as high as 7 per cent, soluble acid, while the aver- 

 age may be placed at 5 per cent. On the other hand, the adulterants 

 used in butter and the substitutes therefor will be found to contain only 

 5 per cent, or less of soluble acid. It may be granted that no unadul- 

 terated butter will contain less than 4 per cent, soluble acid, while the 

 limit might well be placed at 4.5 per cent, without excluding any desira- 

 ble genuine butter. The estimation, therefore, of the soluble acid is an 

 argument convincing alike to the chemist and the court whenever the 

 purity of a butter is called in question. 



There is nothing particularly novel in the method which has been em- 

 ployed in the present work, but a brief summary of it will be given. 



