It produces on cotton and
wool a bright yellow colour without the aid of any mordant. To show you
how easily dyeing with turmeric is effected, I will warm some powdered
turmeric root in a flask with alcohol, and add the extract to a vessel
of water warmed to about 140 deg. F. (60 deg. C.), and then dip a piece of
cotton in and stir it about, when it will soon be permanently dyed a
fine bright yellow. A piece of wool similarly worked in the bath is also
dyed. However, the unfortunate circumstance is that this colour is fast
neither to light nor alkalis. Contact with soap and water, even, turns
the yellow-dyed cotton, reddish-brown.
Annatto is a colouring principle obtained from the pulpy matter
enclosing the seeds of the fruit of a tree, the _Bixa orellana_, growing
in Central and Southern America. The red or orange colour it yields is
fugitive, and so its use is limited, being chiefly confined to silk
dyeing. The yellow compound it contains is called "Orellin," and it also
contains an orange compound called "Bixin," which is insoluble in water,
but readily soluble in alkalis and in alcohol with a deep yellow colour.
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