ADULTERATION AND DETECTION. 



injurious than the Chinese compound, and used only in 

 the manipulation and sophistication of the lower or com- 

 moner grades of tea in that country. 



The process of coloring or facing Green teas is per- 

 formed by placing a portion of Prussian blue in a 

 porcelain bowl, not unlike a chemist's mortar, and pul- 

 verizing it into a fine powder, a small quantity of 

 gypsum being meanwhile burned over a charcoal fire, to 

 soften it, after which it is ground fine. The two sub- 

 stances are next mixed together, in the proportions of 

 one part blue to four parts gypsum, both making in 

 combination a light-blue preparation, in which state 

 it is applied to the leaves during the last process of 

 firing, about five minutes prior to removal from the pans, 

 the time being regulated by a burning joss stick. The 

 Saihoo taking a handful of the compound, scatters it 

 over the leaves while in the pans, other operators tossing 

 and turning the leaves around rapidly with their hands 

 meantime in order that it may equally diffuse among 

 them. One ounce of coloring-matter will face fifteen 

 pounds of leaves, imparting to them a dull leaden-blue 

 hue, and " glossy " or greasy appearance, readily detected 

 in the hand. In many districts, most notably in Ningpo 

 and Canton, tumeric, kaolin, and China clay are more 

 extensively employed for the purpose. This almost trans- 

 parent form of adulteration is readily detected in the 

 following manner : 



(i) When the tea is heavily coated it may be easily 

 recognized by its dull leaden-blue color and greasy 

 appearance in the hand, or by placing a small quantity 

 of the leaves on a piece of glass or smooth table, on 

 removing them the coloring-matter will be found adhering 

 to the hands, glass or table, and its nature, whether Prus- 

 sian blue, tumeric, kaolin or indigo, readily determined 



