ADULTERATION AND DETECTION. 



tea, dried after the manner of tea, may serve to illustrate, 

 the leaves being gathered towards the end of August : 



Kind of Leaf. Per cent, of Ash. 



Ash, ............... 940 



Plum, ............. . 9.90 



Willow, .............. 9.34 



To these may be appended the determinations of 

 Paraguay tea at 28 and the ordinary tea of commerce at 

 5.92 per cent. ; while in Peligot's analysis the average pro- 

 portions of ash in true tea-leaves is given as follows : 



Kind of Leaf. Per cent, of Ash. 



China Tea, ............. 5.5 



Japan " ........ ...... 5.5 



Java " ........... . . 5.3 



India " ............. 6.06 



Ceylon " ............. 6.06 



Proving, as has been mentioned, that genuine tea-leaves 

 as brought direct from the producing countries, or such 

 as is a fair commercial article, does not yield less than 

 5, or sensibly more than 6 per cent, of ash on incineration. 

 When the ash much exceeds 6 per cent, the first question 

 to be considered is whether it is accidental or if the high 

 yield of ash would be maintained if a larger quantity of 

 the sample were incinerated. The composition of the ash 

 of genuine tea-leaves has also been carefully studied, 

 yielding on analysis the following constituents : 



Constituents. Per cent. 



Soda, ........ * ..... 0.65 



Lime, .............. 4.24 



Potash, .............. 39.22 



Silica, ....... ....... 4.35 



Chlorine, . . ..... ...... 0,8 1 



Magnesia, ............. 6.47 



Oxide of iron, , .......... 4.38 



Carbonic acid, ........... 24.30 



Sulphuric acid, .......... A trace 



Pnosphoric acid, .......... 14-55 



Protoxide of manganese, ....... i .63 



Total, .......... loo.oo 



