ore adding each lot of dye-stuff, and
stirring up the contents of the bath before re-entering the goods.
Another important condition of obtaining a level dyeing is to proceed
slowly, beginning with a weak bath at a moderate temperature, and
rising gradually to a boil. If necessary to retard the dyeing from the
commencement, then an assistant mordant is added to the dye-bath, in
the shape of soda crystals or phosphate of soda for the benzidine (p. 081)
colours on cotton; bisulphate of soda or Glauber's salt in dyeing with
azo colours or acid colours on wool; or tartar may be used in most
cases with good effect, causing the wool to have a softer feel. Finally,
the evenness of the dyeing is much increased by the frequent turning
over of the material in the dye-bath, so managing this in the case of
wool as to avoid felting.

When dyeing with a mordant, the dyer should see that the mordanting
operation is thoroughly well done, for as much care is required for
the mordanting as for the actual dyeing; in fact, if anything, the
mordanting should be done with rather more care, as if it be at all
defective no amount of care in the following dyeing operations will
ensure a level dyeing. Chrome mordanted wool should be dyed without
delay, as it is rather sensitive to light, especially the yellow sort,
which gradually changes into the green sort of chromed wool.

One peculiarity of dyed wool is that it will continue to take up
colour after it is removed from the dye-bath, especially if it
contains any of the hot dye-liquor, therefore it is very desirable to
wash the wool as soon as possible after its removal from the dye-bath.
It is best, however, not to take the wool out of the hot bath, but to
leave it in until the bath becomes cool, and then to take it out, by
this means the colour becomes deeper and more solid looking, and is
faster on the wool.

One cause of irregular dyeing may be mentioned, as it is occasionally
met with, namely, the presence of foreign fibres in the goods, cotton
in wool fabrics, and even of different varieties of the same fibre.
All dyers know that dead or immature cotton will not dye up properly,
a fact or defect more especially met with in indigo dyeing than probably
in any other colour. Then wools from different breeds of sheep vary
considerably in their dyeing power. Fine wools take up more colour (p. 082)
than coarse, and, consequently, even from the same bath, will come out a
deeper shade; if a fa