188 Quarterly Abstract of European Chemistry. 



count for but a small portion of the nitrogen. Owing to the difficulty 

 of estimating theine quantitatively, M. Peligot supposed that the quan- 

 tity might be much greater ; and in this he was correct, having obtain- 

 ed from 100 parts of gunpowder tea, taken in its ordinary state, 5"84 

 of theine, equivalent to 6*21 of the same dry ; now the watery extract 

 of the tea contained 4"35 of nitrogen, which represented 7*4 of theine ; 

 but the theine collected indicated only 3'60 of nitrogen, there remain- 

 ing 0*75 to be accounted for. Whether this belonged to any other 

 principle it was difficult to say, but the author thinks it probably arose 

 from some ammoniacal salts formed by a decomposition of a small por- 

 tion of the theine during the treatment with boiling water. The pro- 

 cess by which the mass of theine was abstracted is as follows. Add 

 to the infusion of tea while hot, a slight excess of subacetate of lead, 

 then ammonia, boil for some time, filter, wash with care the lead pre- 

 cipitate, treat the filtered solution with hydrosulphuric acid to separate 

 the excess of lead, concentrate the clear solution by a gentle heat, and 

 upon cooling an abundant crystallization of almost pure theine takes 

 place. The mother water by concentration furnishes another portion. 

 To describe the manner in which the last portions were obtained would 

 occupy too much space. 



One hundred parts of the tea leaves, after having all the soluble matter 

 extracted from them were found to contain about 4*50 per cent, of ni- 

 trogen, due to a substance resembling in its character caseine. The 

 ashes obtained from different kinds of the tea vary from 5*5 to 6 per 

 cent., oxide of iron being a prominent ingredient in them. 



Observations on the Green Teas of Commerce, by R. Wareengton, 

 (Chem. Soc. Mem. Vol. II, p. 73.) — There are some important facts 

 contained in this article concerning the adulteration of teas by the Chi- 

 nese. From almost all green teas a powder can be shaken, exhibiting 

 under the microscope blue and white particles. The blue particles are 

 proved to be prussian blue and the white gypsum. If this powder be 

 washed away by agitating the tea with water, its color becomes chang- 

 ed from a bluish green to a bright lively yellow or brownish yellow 

 tint, and with care it can be re-dried at a temperature below 212° F. 

 without uncurling the leaf or causing it to lose any of its qualities ; 

 when completely dry it appears as dark as the ordinary black teas. 

 One cause of the adulteration of this class of teas appears to be tlie 

 great American demand for this article ; and the coarser black teas are 

 cut up and colored with a preparation of prussian blue and gypsum, to 

 give it a green hue. Leaves of other plants are also used by the Chi- 

 nese to adulterate teas, coloring them in the same way ; and it is said 

 that there are spurious teas sent from China not containing a leaf of lea. 



