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.
Divi-divi consists of the dried pods of the Caesalpinia coriaria (Willd.), a tree 20-30 feet high, found in the West Indies and Central America. The pods are about 3 inches long and j inch broad, are very thin, and frequently resemble in shape the letter S. From 40-45 per cent, of tannin is present, which consists of ellagitannin and probably also a gallotannin. Extracts of this material have a somewhat unfortunate tendency to ferment, with simultaneous development of a deep-red colouring matter; but this can be prevented to some extent by the use of antiseptics. Divi-divi is largely imported for the preparation of leather, and is also employed for black dyeing, but its use is far more limited in this latter respect than myrobalans.
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