omposition, which all have the property of dyeing from baths
containing Glauber's salt and sulphuric acid or acetic acid, the usual
proportions being 10 per cent. of the former, and 2 to 5 per cent. of
the acid. Some are best dyed from a bath containing bisulphate of
soda. The dyeing should be started cold, or at a lukewarm heat, then
steam should be turned on and the temperature raised to the boil, at
which it is maintained for an hour; this boiling serving to more
intimately fix the dye-stuff on the woollen fibre.

The Eosine reds, of which Eosine in its various brands, Rose Bengale,
Phloxine, Saffrosine and Erythrosine, are examples, are best dyed upon
wool from a bath containing Glauber's salt and a little acetic acid.
They do not require a very acid bath, hence the reason of using acetic
acid. The method of dyeing is that given above as for basic reds,
namely, enter into cold, or at most lukewarm bath, and raise the heat
slowly, continuing the work until the shade required has been
obtained. It is a good plan to start work in a neutral bath, and then
when the material has become thoroughly impregnated with the
dye-liquor to add the acetic acid. The shades obtained from these
Eosine reds are remarkable for their brilliance, but unfortunately
their fastness to light, washing, etc., is but slight, although it may
be increased by treating the dyed wool in a bath of alum or acetate of
lead.

Some of the acid reds, _e.g._, Acid Magenta, Acid Violet, belong (p. 105)
to the group of sulphonated basic dyes. The vast majority belong to the
group of azo dyes, which can be employed to dye from palest pinks to
the deepest crimson reds. Some dye very brilliant shades, others only
yield dull reds. Some dye shades remarkable for their fastness to all
agencies, soap, acids, alkalies, light and air; others dye shades
which may be fast to soap, but loose to acids and light. Generally
even shades are readily obtained on any kind of woollen fabric. It is
practically impossible to name all the acid reds that are known and
that may be used, but a fairly representative series of recipes will
be given.

_Ponceau_.--Wet out, then prepare a bath with 2 lb. Ponceau R, 10 lb.
Glauber's salt, 2 lb. sulphuric acid. Enter the wool in the cold,
bring to a boil and work to shade, wash and dry.

_Crushed Strawberry_.--Prepare a bath containing 10 lb. Glauber's
salt, 4 oz. Scarlet R S, 9 oz. Indigo extract, 2 oz. Orange Y, 4 oz.
sulphuric acid