Jarmain : Tea and its Adulterations. 21 



The analysis of Tea gives tlie following result : — 



Extractive matter 31 to 45 7o 



Insoluble matter 43 to 49 % 



Moisture 8 to 10 



Tannin 8 J to 11 J 7o black. 



„ 10 to 20 7o green. 



Theine 1 to 6 7© 



Ash 5-3 to 6*34 — average, 5*75 



Gum variable. 



The modes adopted by analysts for obtaining the above percentages 

 were here described, and experimental illustrations given of some of 

 the processes. 



There are four kinds of sophistication which are practised : — 

 (a) the mixing of leaves which are not Tea ; (b) the mixture of 

 exhausted Tea leaves which have been re-dried ; (c) the addition of 

 sand and other mineral matter ; (d) colouring or facing. 



(a) The adulteration of Tea with foreign leaves is but little, if at 

 all, practised at the present day in this country ; but formerly 

 the leaves of the willow, hawthorn, sloe, beech, elder, elm, and others 

 were used. These can readily be distinguished from true Tea by the 

 botanical characters already alluded to. A substance known under 

 the name of lie Tea has also been extensively used. This lie Tea is 

 no Tea at all, but is a made-up article, and is manufactured for 

 the purpose of adulteration. 



(6) The mixture of exhausted Tea leaves, which have been re-dried, 

 is one of the principal forms of adulteration practised at the present 

 time. As the Tea so treated would be weak and poor, an attempt is 

 made to restore artificially what it has lost by infusion. This is done 

 by the admixture of tannin, in the form of catechu and gum, to give 

 the required gloss. The Canton caper Teas are frequently made up 

 in this way. A variation in the percentage of tannin and gum often 

 gives a clue to this form of adulteration ; also, a certain roughness 

 and astringency in the taste of the Tea. I am at present working a 

 process which promises to give us useful indications of this form of 

 adulteration : it consists in using Tea as a preparation for dyeing 

 cotton with a salt of iron. The colour obtained is so very different 

 from that given by catechu under similar conditions, that I feel 

 persuaded that it will not only enable us to detect, but to estimate 

 the quantity of catechu used. The accomplishment of this is a great 

 desideratum at the present time. Samples of cotton which had been 



