of Black and Green Tea. 205 



distinct vegetable principle; namely, that they deposit, as they 

 cool, a brown pulverulent precipitate, which passes through 

 ordinary filters, and can only be collected by deposition and de- 

 cantation ; this precipitate is very slightly soluble in cold water 

 of the temperature of from 50° downwards, but it dissolves with 

 the utmost facility in water of 100° and upwards, forming a pale 

 brown transparent liquid, which furnished abundant precipitate 

 in solutions of isinglass, of sulphate of iron, of muriate of tin, 

 and of acetate of lead ; whence it may be inferred to consist of 

 tannin, gallic acid, and extractive matter. 



When tea leaves have been exhausted by water repeatedly af- 

 fused, the above experiments shew that alcohol is still capable 

 of extracting a considerable quantity of difficultly soluble mat- 

 ter; this substance, again infused in boiling water dissolves with 

 difficulty, furnishing a liquid which smells and tastes strongly 

 of tea, and which, were it not for the expense of the solvent and 

 the trouble attending its separation, might perhaps be profitably 

 employed. 



Though the above experiments shew that tea contains, upon 

 an average, from 30 to 40 per cent, of matter soluble in boiling 

 water, it is not to be supposed that so large a proportion is taken 

 up in the ordinary process of making tea; on the contrary, 

 from tea leaves in the state in which they are usually thrown 

 away, there is still contained from 10 to 14 per cent, of soluble 

 matter, capable of affording a sufficiently pleasant beverage, 

 though it must be granted that the most agreeable portion of the 

 tea, consisting probably of the purer tannin, or astringent matter, 

 and of the whole of the aroma, is taken up by the first affusion 

 of hot water; and that, subsequently, the bitter and less soluble 

 extractive matter are dissolved, furnishing what is usually called 

 strong tea, but infinitely less agreeable than the earlier infusion. 

 Hence it is that the real epicure in this article imitates, in some 

 measure, the Chinese process of infusion ; and only drinks the 

 first made tea, using a fresh, but small proportion of the leaves 

 for each successive cup. 



The following tabic shews the respective ([uantitics of soluble 



