TEA 973 



When an infusion of tea is evaporated to dryness, a chocolate-brown residue re- 

 mains, which, when derived from green gunpowder, contains 5'35 per cent, of nitrogen ; 

 if from black souchong, 470 per cent, nitrogen. 



The subacetate of lead throws down about half the soluble constituents contained 

 in this infusion. The precipitate, which is of a more or less dark yellow, according 

 to whether it is derived from green or black tea, contains the whole of the colouring- 

 matter, the whole of the tannin, and a peculiar acid, which affords an insoluble salt 

 of a light yellow colour with the subacetate of lead. 



To determine the amount of theine, M. Mulder evaporates the infusion with caustic 

 magnesia, and treats the residue with ether, which only dissolves out the theine. On 

 modifying this process, Dr. Stenhouse has obtained the following quantities of theine 

 from 100 parts of 



Hyson 2'40 



Another kind . 2'56 



Mixture in equal parts of gunpowder, hyson, imperial, \ 2 . _ Q 



caper, and pekoe J 



Gunpowder 4'1 



Another kind ...... 3'5 



These quantities are far more considerable than have been obtained by M. Mulder ; 

 but, at the same time, they do not account for the total amount of nitrogen of the 

 infusion in the state of theine, for the composition of theine being represented by 

 the formula C 8 H 5 N'0 2 (C 8 K U W 4 O 2 ), and this substance containing 29'0 per cent. 

 of nitrogen, gunpowder tea should contain 7'4 and souchong 6 - 5 theine in 100 parts of 

 these teas taken in their ordinary state, if no other nitrogenous substance accompanied 

 the theine in the solution. 



The portion of tea from which boiling water extracted no more soluble principle 

 contained in 100 parts, dried at 230, 4'46 nitrogen for the souchong, and 4'30 for the 

 gunpowder. These quantities, added to those of the infusion, represent very nearly 

 the nitrogen ascertained by analysis to exist in the entire leaf. 



On boiling for some time the exhausted leaves in water containing ^th of their 

 weight of potash, a brown liquid is obtained, which affords, on the addition of dilute 

 sulphuric or acetic acid, a considerable flocculent and brown precipitate, which con- 

 tains 8'45 per cent, of nitrogen ; the product of another preparation gave 9'93. Al- 

 cohol and ether remove from this precipitate about 30 per cent, of a green substance, 

 which appears to contain a fat acid. This product is not pure after this treatment, 

 for it is strongly coloured and contains pectic acid ; nevertheless, that which con- 

 tained 8 -4 5 nitrogen afforded 11-35 of this element after being treated with alcohol 

 and ether. 



The Chinese method of making Black Tea. In the first place, the youngest and 

 most tender leaves are gathered; but when there are many hands and a great 

 quantity of leaves to be collected, the people employed nip off with the forefinger 

 and thumb the fine end of the branch with about four leaves on, and sometimes even 

 more, if they look tender. These are all brought to the place where they are to bo 

 converted into tea ; they are then put into a large, circular, open-worked bamboo 

 basket, having a rim all round, two fingers broad. The leaves are thinly scattered on 

 these baskets, and then placed in a framework of bamboo, in all appearance like the 

 sule of an Indian hut without grass, resting on posts, 2 feet from the ground, with an 

 angle of about 25. The baskets with leaves are put in this frame to dry in the sun, 

 and are pushed up and brought down by a long bamboo with a circular piece of wood 

 at the end. The leaves are permitted to dry about two hours, being occasionally 

 turned ; but the time required for this process depends on the heat of the sun. When 

 they begin to have a slightly withered appearance, they are taken down and brought 

 into the house, where they are placed on a frame to cool for half an hour. They are 

 then put into smaller baskets of the same kind as the former, and placed on a stand. 

 People are now employed to soften the leaves still more, by gently clapping them be- 

 tween their hands with their fingers and thumb extended, and tossing them up and 

 letting them fall, for about five or ten minutes. They are then again put on the frame 

 during half an hour, and brought down and clapped with the hands as before. This 

 is done three successive times, until the leaves become to the touch like soft leather ; 

 the beating and putting away being said to give the tea the black colour and bitter 

 flavour. After this the tea is put into hot cast-iron pans, which are fixed in a circular 

 mud fireplace, so that the flame cannot ascend round the pan to incommode the ope- 

 rator. This pan is well heated by a straw or bamboo fire to a certain degree. About 

 2 Ibs. of the leaves are then put into each hot pan, and spread in such a manner 

 that all the leaves may get the same degree of heat. They are every now and then 

 briskly turned with the naked hand, to prevent a leaf from being burned. When the 



