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 conversant with the Chinese manufacture, that the leaves for the black teas were always allowed to remain exposed to the air in mass for some time before they were roasted.' This explanation by Mr Warrington from scientific data, is confirmed by Mr Fortune from personal observation, and fully accounts, not only for the difference in colour between the two teas, but also for the effect produced on some constitutions by green tea, such as nervous irritability, sleeplessness, &c.; and Mr Fortune truly remarks, that what Mr Warrington observed in the laboratory of Apothecaries' Hall, may be seen by every one who has a tree or bush in his garden. Mark the leaves which are blown from trees in early autumn; they are brown, or perhaps of a dullish green when they fall, but when they have been exposed for some time in their detached state to air and moisture, they become as black as our blackest teas. Without detailing the whole process in the manufacture of either kind of tea, it may be stated in reference to green tea, _1st_, That the leaves are roasted almost immediately, after they are gathered; and _2d_, That they are dried off quickly after the rolling process. In reference to black tea, on the other hand, it may be observed, _1st_, That after being gathered, the leaves are exposed for a considerable time; _2d_, That they are tossed about until they become soft and flaccid, and are then left in heaps; _3d_, That after being roasted for a few minutes and rolled, they are exposed for some hours to the air in a soft and moist state; and _4th_, That they are at last dried slowly over charcoal fires. After all, then, genuine green tea is, as might reasonably be conjectured, an article less artificial than black. There is, at the same time, too much foundation for the suspicion, that the green teas so much patronised in Europe and America, are not so innocently manufactured. Mr Fortune witnessed the process of colouring them in the Hung-chow green-tea country, and describes the process. The substance used is a powder consisting of four parts of gypsum and three parts of Prussian blue, which was applied to the teas during the last process of roasting.