EXPERIMENTS ON COLOUR. 241 



established opinion in Europe that green tea derived 

 its grey or bluish appearance from being dried on 

 copper. The preceding accounts demonstrate that 

 such an opinion is altogether unfounded. The 

 same colour can be produced by drying the leaves 

 in a copper vessel, as I have proved by experiment ; 

 but the tea thus dried appeared to me to partake of 

 the flavour of the vessel ; and consequently a vessel 

 which produces a flavour so objectionable is not 

 likely to be employed. Nor does this peculiarity 

 of colour arise from any metallic influence of the 

 vessel in which the leaves are roasted, for I found 

 by experiment, that the same bloom-like colour 

 could be produced in an earthen vessel. 



The reader will now remember, — and I wish to 

 draw his attention particularly to this fact, — that 

 one of the inferior methods of completing the final 

 desiccation of black tea was by means of the iron 

 vessel denominated a Kuo, in lieu of the poey long 

 or drying-tube commonly used: which inferior 

 method does not seem essentially different from the 

 mode now described of making green tea. In order 

 therefore to discover to what so great a difference 

 of colour, produced by means almost similar, was 

 due, I went through the following experiments. 



1. I put a small parcel of Honan leaves into a 

 common culinary kuo, and after having roasted 

 and rolled them twice, I divided them into two 

 parcels. I then completed the roasting of one 

 parcel with as fierce a fire as I could bear, keeping 



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