being to
select dyes which have an equal affinity for the two fibres or which
give but slightly different shades. Still, some good effects are
obtained when dyes are used which dye the silk and wool different
colours but give the combined effect of a self-colour. Or the fibre
may be purposely dyed in two different colours in some cases to give
the "shot" effect. This is much more troublesome, but with a little
care can be carried out with good results. The dyes available for
dyeing gloria may be classified, according to their behaviour in
regard to their dyeing of the two fibres, into three groups as
follows:--

_Group A_.--Those which will dye the two fibres of equal shade.

_Group B_.--Those which will dye the wool at boiling heat more readily
than the silk.

_Group C_.--Those which will dye the silk only in a cold bath.

_Group A_ consists of those dyes which can be used in dyeing
self-colours on gloria from acid baths. It includes Alkali Blue,
Naphthylamine Blacks, Naphthol Green B, Indian Yellow, Croceine A Z,
Croceine Orange, Orange R, Brilliant Croceine M, Rose Bengale,
Thiocarmine R, Soluble Blue, Formyl Violet S 4 B, Acid Green, Croceine
Orange G, Carmoisin, Acid Violet 5 B, Fast Acid Violet 10 B, Fast
Green Bluish, Rhodamine, Silk Blue, Victoria Black, Archil, Turmeric,
Safranine, Auramine, Quinoline Yellow, Azoflavine, Victoria Blue and
Bismarck Brown.

_Group B_ comprises those dye-stuffs which in a boiling acid (p. 190)
bath dye the wool deeper than the silks, in other words have more
affinity for the wool than the silk, Tropaeoline O, Acid Magenta,
Indigo Extract, Phloxine, Naphthol Yellow, Orange G G, Scarlet S, Azo
Red A, Eosines, Thiocarmine R, Naphthol Black B B, New Victoria Black
Blue, Erythrosine, and Roccelline.

The silk becomes tinted to a more or less extent when in such a bath,
but often the colour is readily removed either by subsequent passage
through boiling water or through hot soap liquor. A very good clearing
can be effected by the use of a bath of acetate of ammonia. Naphthol
Yellow, for instance, only imparts a very faint shade of yellow when
thus dyed, and this is easily removed by boiling-water treatment.

_Group C_.--Those dye-stuffs which will dye the silk more readily in a
cold bath than the wool. These comprise most of the basic dyes, such
as Thioflavine T, Safranine, Brilliant Green, Methyl Violet, Magenta,
New Methylene Blue, Bismarck Brown, Rose Bengale, Phloxine