2 40 Mr R. Warrington on the 



Observations on the Teas of Commerce. By R. WARRINGTON, 



Esq., F.C.S. 



In my previous communication to the Society on this sub- 

 ject in February 1844,* I endeavoured to shew that there 

 exist two distinct kinds of green tea, known in commerce as 

 glazed and unglazed ; that the former is coloured by the 

 Chinese with a mixture of Prussian blue and gypsum, to which 

 a yellow vegetable colouring matter is sometimes added, while 

 the latter are merely dusted with a small quantity of gypsum ; 

 that in the specimen of the so-called Canton gunpowder, 

 this glazing or facing is carried to the maximum. I also 

 mentioned, that I had never met with a sample of green tea 

 in which the blue tint was given by means of indigo. Since 

 the publication of that paper, I have been in communication 

 with several parties of great experience in this subject, from 

 whom I have received much additional information, which, 

 with several experimental points of interest that have come 

 under my own immediate observation, will form the subject 

 of the present paper. 



The first point to which I wish to call the attention of the 

 Society is, the question of the blue colouring matter used by 

 the Chinese for colouring the green teas being Prussian blue, 

 because some doubts have been thrown on this subject from 

 various quarters. Mr Bruce thus states :f — " The Chinese 

 call the former (the indigo) Toungtin, the latter (the sulphate 

 of lime) Acco,^' Now I am favoured with the opinion of Mr J . 

 Reeves on this point, whose knowledge and experience ren- 

 der him most competent to decide in such a case ; he believes 

 that indigo is never employed for colouring used in tea, that 

 the term Toungtin, as used by Mr Bruce, should be Yong- 

 ieen, foreign blue, the name given by the Chinese to Prussian 

 blue in contradistinction to Too-teen, native blue or indigo ; 

 this, I think, is very conclusive evidence, and shews that 

 Mr Bruce's statement was erroneous. 



In another quarter a surmise has also been published on 



* Memoirs and Proceedings of the Chemical Society, ii., 73. 



t Report on the Manufacture of Teas, &c. By C. A. Bruce, August 16, 1839. 



