822 



FOODS AND FOOD ADULTERANTS. 



Comparative analyses of pure unbleached and bleached wax afforded the following 

 limiting data : 



In air bleaching the yellow waxes lose only abont 1 to 2 per cent of their weight. 

 The melting point of the two kinds of wax rests sensibly the same. Only traces of 

 acids soluble in water are formed during the bleaching process. The most notable 

 differences are in the quantities of hydrocarbons, which fall from 13 to 14 in the yellow 

 wax to 11 or 12 in the white variety, and the iodine number, which falls about four 

 points in the white wax. The proportion of total acids in the white variety is slightly 

 increased. In bleaching, some of the nonsaturated constituents of the wax fix oxy- 

 gen and become saturated, thus diminishing their power of absorbing iodine. 



This is illustrated particularly in the hydrocarbons of the wax which, after bleach- 

 ing, melt at 51.5 to 53 degrees, and fix 14.3 to 15 per cent of iodine, and before bleach- 

 ing melt at 49.5 degrees and fix 22 per cent iodine. 



In practice the pure wax is rarely bleached. The bleachers always add to the wax 

 a certain q uantity of suet, from 3 to 5 per cent. There are several reasons for this. 

 The principle one is that pure wax when bleached is too brittle ; moreover, in 

 presence of a small quantity of suet, the bleaching goes on more rapidly, and without 

 this suet it is difficult to obtain a product entirely white. 



A series of yellow waxes to which a small quantity of suet had been added, fresh 

 suet, and the same exposed to air and left for forty days, gave on analysis the fol- 

 lowing comparative and limiting data : 



These numbers illustrate the action of the suet in bleaching. It is due to the oleio 

 acid it contains ; easily oxidizable, thus aiding the combustion of the organic coloring 

 matter. The essence of terebenthine added in small quantities acts in the same 

 manner. 



Other processes may be employed for the decoloring wax, e. g., bleaching with animal 

 charcoal. The wax is kept in a fused state in contact with the black, and the white 

 wax is obtained by filtration. Permanganate of potash or bichromate of potash 

 may also be employed in acid solution with good results and even oxygenated water. 



Reducing agents, such as sulphurous acid, sulphites, hydrosulphitea; etc., do not act 



