The Natural Organic Colouring Matters
By
Arthur George Perkin, F.R.S., F.R.S.E., F.I.C., professor of colour chemistry and dyeing in the University of Leeds
and
Arthur Ernest Everest, D.Sc., Ph.D., F.I.C., of the Wilton Research Laboratories; Late head of the Department of Coal-tar Colour Chemistry; Technical College, Huddersfield
Longmans, Green and Co.
39 Paternoster Row, London
Fourth Avenue & 30th Street, New York
Bombay, Calcutta, and Madras
1918
Kaikki kuvat (kemialliset kaavat) puuttuvat // None of the illustrations (of chemical formulas) included.
This very important tanning material consists of the fruit or nuts of the Terminalia chebula, a tree of from 40-50 feet high, which grows in China and the East Indies. These nuts, which resemble a somewhat shrivelled plum, contain from 30-40 per cent, of tannin, the unripe fruit containing the largest amount. They should be bright in colour, and not soft, and require to be kept in a dry place, otherwise they absorb moisture and are then difficult to grind. The tannin present consists of a gallotannin, which is at least in part chebulinic acid, together with a fairly large amount of ellagitannin, and this, owing to fermentation and other causes, is decomposed to some extent during lixiviation into ellagic acid. Myrobalans from the dyer's point of view is one of the most serviceable tannin materials at the present time. Enormous quantities of its extract, especially as purified or decolorised extracts, are manufactured, and these are employed for cotton dyeing, in the black dyeing of silk, and in tanning.
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