THE INVESTIGATION AND TESTING OF BUTTER. 195 



Potassium oxide, 19*329 



Sodium oxide, 7*714 



Calcium oxide, 23*092 



Magnesium oxide, ... ... ... ... 3*287 



Phosphoric anhydride, ... ... ... ... 44*273 



Chlorine, 2*604 



Iron, sulphuric acid, and loss, 0*288 



100*587 

 Deduct oxygen replaced by chlorine, 0*587 



100*000 



The quantity of phosphoric acid quoted above includes that formed by the 

 burning of the phosphorized lecithin. 



106. The Investigation and Testing of Butter. Ordinary chemical 

 analysis of butter offers no special difficulty. If butter is to be 

 tested for adulterants, the methods used in determining its chemical 

 composition are for the most part not available. The processes 

 used for this purpose are of a special kind. In such a test of butter, 

 what is sought for is the presence of (1) deleterious colouring mat- 

 ters; (2) preservatives; (3) unusual quantities of water, or of foreign 

 solid bodies which have been added to the butter for the sake of in- 

 creasing its weight; and (4) foreign fats. The substances mentioned 

 under Nos. 1, 2, and 3 demand difficult and complicated methods of 

 investigation, so that they can only be carried out by a chemical 

 specialist. On the other hand, it is easy to detect adulteration of 

 butter with water, which is the most common of the above-men- 

 tioned adulterants. This method of adulteration is easily effected 

 by melting unsalted butter in hot water, and by stirring up the fat 

 with the water; or by working unsalted butter in salt water, or 

 working salted butter with fresh water. The weight of the butter 

 can be increased by this action to the extent of 26 per cent. 

 Owing to the wide extension of the trade in margarine, and its 

 use as an article of consumption, as well as the custom of selling 

 margarine as butter, the investigation of butter for foreign fat, or 

 the difference between butter and other fats, is especially important. 

 The most valuable methods of research used for this purpose, are 

 based upon the fact that butter-fat contains a number of neutral 

 fats, with volatile easily-soluble fatty acids, forming on an average 

 about 8 to 9 per cent of its weight, which in other fats are either 



