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Catechu Is An Extract Of The Khair Tree Or Acacia Catechu Of Bombay








Bengal, and other parts of India. With the exception of such earthy
matters as are communicated to it during the preparation, or are added
purposely as adulterants, catechu is entirely soluble both in water and
alcohol. An aqueous solution has a reddish-brown colour, and gives the
following results:--protosalts of iron thrown down olive-brown and
persalts greenish-brown precipitates; salts of tin and lead yield
brownish-yellow and brick-coloured deposits respectively; while acetate
of copper or bichromate of potash furnishes brown residues. To our
knowledge, none of these have been introduced as pigments, but a brown
prepared by Dr. Lyon Playfair some years back from the catechu bark has
been described as exceedingly rich, transparent, and beautiful; and





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