REPORT OF THE CHEMIST. 



285 



According to Sclieffer, mixtures of pure butter and lard gave the 

 f oUowine: data: 



A trial of this method has shown that it is capable of giving valua- 

 ble qualitative indications in respect of the purity of the sample under 

 examination. 



The best method to secure a sensibly uniform -weight of fats is to 

 melt them and measure out from a pipette one cubic centimeter of 

 each. The fats which do not melt ^asily should be stirred up thor- 

 oughly with a wire, while the temperature is raised from 18 to 2S^ C. 



ANALYSES OF BUTTERS AND BUTTER SUBSTITUTES. 



In the following tables are found the analyses of — 



(1) Butters which are shown by the analyses to be genuine. 



(2) Butters which are doubtful on account of low specific gravity 

 and a low amount of soluble acid. 



(8) Oleomargarines, butterines, oils, and lards. 

 The follovring methods of analyses, not already described, were 

 employed: 



SPECIFIC GRAVITY. 



Preparation of the sample. 



About half a pound of the butter is melted in a dry beaker in the 

 water bath, stirred occasionally, and when the whole has melted and 

 the water and curd have settled to the bottom the clear fat is poured 

 on a ribbed filter in a jacketed funnel. If the filtrate is not perfectly 

 clear and bright it must be refiltered after being reheated. A tem- 

 perature of 45° to 50° C. will be found most suitable to effect the melt- 

 ing; a higher temperature should be avoided, as otherwise the density 

 may be largely increased. For this reason the fat is kept in a melted 

 condition as short a time as possible. 



DETERMINATION OF THE SPECIFIC GRAVITY. 



The filtered fat is melted on the water bath at 45° C. and poured into 

 an ordinary 25-cubic-centimeter specific-gravity bottle. The bottle, 

 with its contents, is then placed in a shallow glass dish full of warm 

 water and kept at the temperature of 40" C. for ten minutes. The water 

 in the dish should be nearly on a level with the top of the bottle. The 

 bottle is kept full by the addition of more fat if necessary. At the end 

 of the specified time the stopper is inserted, the excess of fat mped off, 

 and the bottle withdrawn from the bath, Aviped thoroughly, and al- 

 lowed to cool before weighing. The increase in weight is equal to the 



