Scour and rinse the feathers well; grays can be used in their natural
color without bleaching. Prepare a warm bath, in which dissolve
eighty per cent., of the weight of feathers, tartaric acid and eighty
per cent. Glauber salt; then add sixteen per cent. aniline fast
brown; eight per cent. azo yellow, and sixteen per cent. induline
or nigrosine, and bring the bath to a boil; after a few minutes of
boiling, chill by the addition of cold water, enter the feathers and
work them at hand-heat for fifteen or twenty minutes until the color
has become level; then bring the bath again to near the boiling point;
lay the feathers down in the bath, shut off the steam, or withdraw from
the fire, and let the bath cool down. When cold, that is in about one
or two hours, take out the feathers, rinse and dry.