Cedrela toonaCHAPTER XVIII. Colouring Matters of Unknown Constitution. (Osa artikkelista)

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.

The Cedrela toona, the Toon or Indian mahogany tree, is a large tree 50 to 60 feet, although occasionally reaching 100 feet in height, the wood of which closely resembles mahogany and is imported into England under the name of "Moulmein Cedar" and much used for making furniture. It occurs in the tropical Himalaya from the Indus eastward, throughout the hilly districts of Central and Southern India to Burma, and is also found in Java and Australia. The flowers constitute one of the less important Indian natural dyestuffs, and are reputed to yield both a red and a yellow dye (known in Bengal as "Gunari," which is applied without mordants). Although considerably employed for dyeing purposes alone, the flowers are also used in Burma in conjunction with safflower and together with turmeric to produce the sulphur-yellow colour or "basanti" of Cawnpore.

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Cotton and woollen fabrics can be dyed a dull yellow colour by mere immersion in a boiling extract of Toon flowers. This, however, is not permanent and is removed, although much more quickly from cotton than wool, by the action of soap or dilute alkali. Better results are obtained by the employment of mordants, and the following shades were obtained with mordanted woollen cloth:

Chromium - Dull brownish-yellow.
Aluminium - Full golden-yellow.
Tin - Bright yellow.
Iron - Dull olive-brown.

During these operations, nycanthin or its glucoside apparently plays no part, and the colours obtained are due to the flavone glucosides present. Not only the flowers but the seeds of the Cedrela toona are stated to give a red dye.