Teas of Commerce. 241 



this same point. Mr Fortune, in his entertaining work* on 

 China, says, speaking of the ingredients used in dyeing the 

 northern green teas for the foreign market, p. 201; " There 

 is a vegetable dye, obtained from Isatis Indigotica, much 

 used in the northern districts, and called Tein-ching, and it 

 is not unlikely that it may be the substance which is em- 

 ployed." Again, at p. 307, " I am very much inclined to be- 

 lieve that this (the Tein-ching) is the dye used to colour the 

 green teas which are manufactured in the north of China, for 

 the English and American markets." This question, how- 

 ever, I think is now satisfactorily settled, and the experi- 

 mental evidence I have adduced of the material being Prus- 

 sian blue of a darker or a paler tint, placed beyond a doubt 

 by a positive demonstration ; for Mr Fortune has forwarded 

 from the north of China, for the Industrial Exhibition, speci- 

 mens of these materials, which from their appearance, there 

 can be no hesitation in stating are fibrous gypsum (calcined), 

 turmeric root, and Prussian blue ; the latter of a bright pale 

 tint, most likely from admixture with alumina or porcelain- 

 clay, which admixture may account for the alumina and 

 silica found as stated in my previous paper, and the presence 

 of which was then attributed possibly to the employment of 

 kaolen or agalmatolite. 



Mr J. R. Reeves, in a letter to my friend Mr Thomson, 

 dated July 1, 1844, commenting on my paper, says : " Mr 

 Warrington's experiments have led him to correct results as 

 to the substances used, which I know to be Prussian blue, 

 gypsum (fibrous), and turmeric : the second being sulphate 

 of lime ; and the last, the yellow, or orange-coloured vege- 

 table substance, which Mr W. does not otherwise name. 

 That the colouring is not intended as an adulteration, I feel 

 quite sure. It is given to suit the capricious taste of the 

 foreign buyers, wlio judge of an article used as a drink by 

 the eye instead of the palate. You well know how little the 

 London dealers, even now, like the yellowish appearance of 

 uncoloured green tea. The Americans, a few years since, 

 carried the dislike even further than the English, and there- 



* Three Years Wandering in the Northern Provinces of China. By Robert 

 Fortune. 



