yeing with Eosine Colours.=--After the treatment with stannate of
soda and sulphuric acid the prepared cotton is ready for dyeing. This
process is carried out by preparing a cold bath with the required
dye-stuff, entering the cotton therein, and then slowly raising to about
180 deg. F., and maintaining at that heat until the desired shade is
obtained. It is not needful to raise to the boil and work at that heat.
No better results are obtained, while there is even a tendency for
colours to be produced that rub badly, which is due to the too rapid
formation of the colour lake; and it is worthy of note that when a
colour lake is rapidly formed on the fibre in dyeing it is apt to be but
loosely fixed, and the colour is then loose to both washing and rubbing.

* * * * *

_Dyeing with Acid and Azo Dyes._

In dyeing with this class of colours stannate of soda, acetate of lead
or alum may be used as mordants. The stannate of soda is employed in the
same manner as when the eosines are used, and, therefore, does not
require to be further dealt with.

Acetate of lead is used in a similar way. The cotton is first steeped in
a bath of acetate of lead of about 10 deg. Tw. strong, used cold, and from
half an hour to an hour is allowed for the cotton to be thoroughly
impregnated with the lead solution, it is then wrung and passed a second
time into a bath of soda, when lead oxide or lead carbonate is deposited
on the cotton. After this treatment the cotton is ready for dyeing with
any kind of acid, azo and even eosine dyes, and this is done in the same
manner as is used in dyeing the eosines on a stannate mordant. The
shades obtained on a lead mordant cannot be considered as fast; they
bleed on washing and rub off badly.

When alum is used as the mordant it may be employed in the same way as
acetate of lead, but as a rule it is added to the dye-bath direct, and
the dyeing is done at the boil. This latter method gives equally good
results, and is more simple.

The eosines and erythrosines, water blues, soluble blues, croceine
scarlets, cloth scarlets, and a few other dyes of the azo and acid
series are used according to this method. The results are by no means
first class, deep shades cannot be obtained, and they are not fast to
washing, soaping and rubbing.

The methods of employing the much more important group of colouring
matters known as the mordant dyes, which comprise such well-known
product