In Hookers Journal of Botany, 1852, is an interesting account by Mr. Bershold See-man, naturalist of H. M. Ship Herald, containing some particulars of the processes of converting, by means of a facing or glaze, the low qualities of black tea, (Bohea Saushung,) valued at 4d to 6d per pound into high quality, green teas valued at Is. to Is. 6d. per pound, a Iraud practised openly at Cariton. The lollowing is his own account:— I heard so much about tea, copper plates, picking the leaves, rolling them up with the fingers, boiling them in hot water, &c, that I became anxious to see with my own eyes the process of manufacture, of which the various books had given me such a confused idea.—: One of the great merchants conducted me not only to his own, but also to another establishment, where the preparation of the different sorts was going forward. There was no concealment of mysterious proceedings, every thing was conducted openly, and exhibited with the greatest civility; indeed, from all I saw in the country, I was almost inclined to conclude that either the Chinese have greatly altered, or their wish to conceal or mystify every thing, of which so much has been said never existed. The tea is brought to Canton unprepared. Alter its arrival it is first subjected to cleaning. Women and children are employed to pick out the pieces of twigs, seeds, and other impurities, with which it happens to be intermixed. The sorts which may be called natural are those gathered at different seasons ; the rest are prepared solely by artificial means. Without entering into a description of all those processes, it may suffice to take one as an example. A quantity of Bohea Saushung was thrown into a spherical iron pan, kept hot by means of a fire beneath These leaves were constantly stirred about until they were thoroughly seared, when the dyes mentioned chrome, or sun-colored Daguerreotypes, to the French Academy of Science. M. Niepce states that the morning light has a much greater photogenic action than the evening light. For example, if a prepared plate be exposed in the camera from nine oclock til] noon, the colored impression will be obtained in a much shorter time than if the same experiment were made from noon till three P. M. I am pleased to see this fact mentioned by M. Niepce, and presume that every observing daguerreotypist has noticed, more or less, this curious phenomenon of the suns rays, while to all external appearance the light presents no difference. I found, Irom a number of experiments for several years, with very sensing the globe moving in the direction from A to B. It will be evident that the rays between Nos. 1 and 3, will afford ths most powerful light, by travelling against the momentum of the atmosphere, No. 2 will remain stationary, while Nos. 4, 5, and 6 will travel with the atmosphere, minus the momentum. Now, if two persons are operating, one at A, with the ray No. 4, the other opposite A, with the ray No. 3 ; now No. 3 will be using those rays which travel against the velocity of the atmosphere, and with the globe, being of course the most powerful operative light, while No. 4 will be using those rays which travel with the atmosphere, and, meeting much less friction, possess a less operative power. I have detected a marked difference in the intensity of colors in the prismatic spectrum, between the hours of ten and two oclock, those in the forenoon being higher toned and fuller than those in the afternoon. R. V. De Guinon. Williamsburg, Feb. 26,1853. [If the above theory is correct, the heat should also be greatest before noon.—Ed. below were added, viz., to about 20 lbs. of tea one spoonful of gypsum, one of turmeric, anl two or three of Prussian blue. The leaves instantly changed into a bluish green, and having been stirred for a few moments they were taken out. They of course had shriveled and assumed different shapes irom the heat. The different kinds were produced by sifting. The small, longish leaves tell through the first sieve, forming Young Hyson, while those of a roundish granular shape fell through the last, and constituted Choo-cha or gunpowder. [The blue was no doubt an inferior kind ot indigo and not Prussian blue, as the former is much cheaper. Black teas, as retailed now are highly adulterated ; we suppose there can he no doubt about this. More black tea is now used in the United States, than there was five years ago ; it therefore becomes imperative that something should be done to prevent the sale of adulterated tea.
This article was originally published with the title "Adulteration of Teas" in Scientific American 8, 25, 200 (March 1853)