i6 



FATS, OILS, AND WAXES 



To half a cubic centimetre add 2 c.c. of sulphuric acid to 

 which have been added o-i c.c. of a 5 per cent solution of 

 either j8-naphthol or resorcinol ; the former should give a 

 green colour with a marked fluorescence, while the latter 

 should give a bright red coloration. 



QUANTITATIVE ESTIMATION OF FATS. 



I . By Means of Soxhlefs Extraction Apparatus. — The fact 

 that oils and fats are readily dissolved by ether, chloroform, 

 and light petroleum is made use of in their estimation ; but 

 it must be borne in mind that the method only yields correct 



results provided other substances, which 

 would be extracted by the solvent em- 

 ployed, are absent from the material 

 under examination. 



The general arrangement of the ap- 

 paratus required is given in Fig. i. The 

 flask F, which is half-filled with the sol- 

 vent to be employed, is connected to the 

 extractor by a closely fitting cork. The 

 material to be extracted is put into a 

 thimble made of special quality filter 

 paper and placed in the extractor, which 

 is connected to a reflux condenser (C). 



The method may be conveniently em- 

 ployed for determining the proportion of 

 oil in the reserve food of the castor-oil 

 seed, for example. 



A number of seeds, freed from their 

 testas, are weighed in the thimble, which 

 is then placed inside the extractor ; a few 

 small chips of porcelain are placed in the flask F, which is 

 then weighed and after being half-filled with freshly distilled 

 ether it is attached to the Soxhlet. The apparatus is then 

 connected up. The ether in the flask F volatilizes and 

 passes up the tube T into the extractor and condenser, and 

 gradually fills the Soxhlet ; on reaching a certain level it 

 siphons over into the flask, carrying with it the fat in 



I ^ U H. ^ I 

 \ f 



Fig. I. 



