ence in their appearance
depended upon manipulation, and upon that only. But the objection was
made, that although he had been in many of the tea-districts near the
coast, he had not seen those greater ones inland which furnish the
teas of commerce. Since that time, however, he has visited them,
without seeing reason to alter his statements. The two kinds of tea,
indeed, are rarely made in the same district; but this is a matter of
convenience. Districts which formerly were famous for black teas, now
produce nothing but green. At Canton, green and black teas are made
from the _Thea bohea_ at the pleasure of the manufacturer, and
according to demand. When the plants arrive from the farms fresh and
cool, they dry of a bright-green colour; but if they are delayed in
their transit, or remain in a confined state for too long a period,
they become heated, from a species of spontaneous fermentation; and
when loosened and spread open, emit vapours, and are sensibly warm to
the hand. When such plants are dried, the whole of the green colour is
found to have been destroyed, and a red-brown, and sometimes a
blackish-brown result is obtained. 'I had also noticed,' says Mr
Warrington, in a paper read by him before the Chemical Society, 'that
a clear infusion of such leaves, evaporated carefully to dryness, was
not all undissolved by water, but left a quantity of brown oxidised
extractive matter, to which the denomination _apothem_ has been
applied by some chemists; a similar result is obtained by the
evaporation of an infusion of black tea. The same action takes place
by the exposure of the infusions of many vegetable substances to the
oxidising influence of the atmosphere; they become darkened on the
surface, and this gradually spreads through the solution, and on
evaporation, the same oxidised extractive matter will remain insoluble
in water. Again, I had found that the green teas, when wetted and
redried, with exposure to the air, were nearly as dark in colour as
the ordinary black teas. From these observations, therefore, I was
induced to believe, that the peculiar characters and chemical
differences which distinguish black tea from green, were to be
attributed to a species of heating or fermentation, accompanied with
oxidation by exposure to the air, and not to its being submitted to a
higher temperature in the process of drying, as had been generally
concluded. My opinion was partly confirmed by ascertaining from
parties conve