826 FOODS AND FOOD ADULTERANTS. 



Rosin may be tested for by heating a fragment of the wax for fifteen minutes with con- 

 centrated nitric acid. Pour a little cold water on the wax swimming on the surface 

 and decant the fluid. In the presence of rosin, a yellow, flocky body is thrown down 

 on cooling or on dilution. Ammonia dissolves the flocks and becomes colored red 

 brown. Stearic acid is tested for by Fehling's method, boiling the wax for forty-five 

 minutes with twenty times its weight of alcohol, allowing the resultant solution to 

 cool slowly, filtering and adding water to the filtrate. A precipitate or cloudiness 

 indicates stearic acid. If a negative result is given, stearin should be sought for by 

 Gottlieb's method, based on the solubility of oleate of lead in ether. Stearin if 

 present is liable to influence the test given above for stearic acid. The distinction 

 between the two can be made by means of an alcoholic solution of lead acetate, which 

 causes no precipitate in the filtrate from pure wax or from that adulterated with 

 stearin. 



B. On cooling the wax floats on the top and the fluid remains clear and is bnt 

 slightly yellow. If not adulterated with paraffin the wax is pure. If the specific 

 gravity of the wax be less than 0.960 and no other adulterants have been found the 

 presence of paraffin is assured. 



To take specific gravity of waxes Donath keeps the wax melted for some time in 

 order to extricate air bubbles and then pours into a potash mold. After fully cool- 

 ing the wax is molded into the desired form, brushed over with a camel's hair brush 

 wet with water and the specific gravity taken in a pycnometer. 



DETECTION OF ADULTERANTS.* 



The author says that white wax contains 3 to 5 per cent of tallow, and that man- 

 ufacturers add turpentine or resin in order to impart to wax the requisite tenacity. 

 Hence these additions, unless present in large quantity, cannot be regarded as adul- 

 terants. The specific gravity of wax when higher than 0.964, indicates the presence 

 of stearin, resin, or Japan wax, and when lower than 0.956 paraffin, ozokerit, or 

 tallow is present. Chloroform or fatty oils form a clear solution with dry wax and 

 a slightly turbid one with moist wax. By treating pure beeswax with a saturated 

 solution of borax at 80, the aqueous solution is rendered turbid; when Japau wax 

 or stearin is present, a milky solution is obtained, remaining opaque after cooling. 

 By boiling wax in a solution of soda (1 : 6), pure wax gives a translucent solution. 

 If milky, stearin is present ; if pasty or stiff, Japan wax has been added. When the 

 specific gravity is less than 0.956 and the wax behaves with borax and soda like pure 

 wax, paraffin or ozokerit has been added ; the same result is obtained when the 

 specific gravity is correct and the borax or soda test indicates the presence of Japan 

 wax. Ceresin (white or yellow) forms milky solutions in the borax or soda test, or 

 behaves like beeswax, but has a lower specific gravity. 



MKTHOD OF DETECTING ADULTERATION OF BEKSWAX.t 



Adulteration of beeswax can be detected by the following methods : 

 To determine the specific gravity an egg-sized piece of wax is placed in a beaker 

 with 33 per cent alcohol, shaken vigorously to remove adhering bubbles, and alcohol 

 or water added until the wax just floats. The density of the mixture is then ascer- 

 tained by a spindle. 



To determine the mineral and coloring matters 10 grams are placed in a flask hold- 

 ing about 250 cc., together with 100 cc. of water, and the mixture boiled for several 

 luinntes. After cooling any mineral matter which may be present will be found in 

 the bottom of the flask. On cooling if the water is yellow, turmeric may be present 

 and can be tested for with ammonia. Starch can be tested for with iodine. For 

 further testing Mr. C'larency prescribes the sodium carbonate test. 



Hager, Dingl. polyt. Jour., 236, 356 ; aba. Jour. Chem. Soc., 1881, 40, 316. 

 t A. Clarency, Journ. de pharm. et de chim. (6) 13, 27; Cheiu. Ceutralblatt, 

 188C, 174. 



