22 ANALYSIS AND ADULTERATIONS OF BUTTER. 



of butter without containing a particle of that substance. 

 As the manufacturers of adulterated articles become educated 

 and conversant with analytical methods, they employ the 

 thermometer in the preparation of spurious butter, as the 

 milk dealers are known to employ the lactometer or even 

 chemical tests in the mixing of the watery liquids called 

 milk. The melting point, taken alone, is therefore valueless ; 

 it assumes importance only when used as corroboration of the 

 results obtained by other methods. 



We think it well, however, to give the methods which 

 have been devised, as the various plans proposed, intended 

 more especially for determining the fusing point of butter, 

 apply also to the other solid fats. We arrange the methods 

 in the order in which they appear to have been published as 

 near as this can conveniently be done. 



The method adopted by Drs. Parkes and Campbell Brown 

 was the first to bring the fusing point of butter at all under 

 control. It was based upon the obscuration of the gradua- 

 tions of the thermometer by the gradually cooling fat, which 

 was placed in a test-tube with the thermometer, and the whole 

 immersed in water; heat being applied, two points, called 

 respectively the "softening" and the "melting," were ob- 

 tained. On cooling, the fat gradually obscures the readings, 

 and thus three other points were obtained. They are shown 

 in the following table, published in the Chemical News by 

 Dr. C. Brown. 



In this method the range of temperature given is extremely 

 large, and the difference of 7 between the two first butters 

 tabulated shows that the point of fusion is not well defined. 

 We endeavoured to fix such a point, and to bring it more 

 under control by the use of a little weight which, being 

 placed upon the top of the fat to be fused, will sink when 

 the fat is so far liquefied as to present less resistance than 

 the weight can overcome. 



