ing to ascertain if any
alkali has been absorbed. If the caustic taste is permanent the
strengthening operation is complete, but should any caustic have been
absorbed, further addition of alkali must be made and the boiling
continued. These remarks apply equally to all soaps.

The soap, when ready, is fitted.

Bleached palm oil, olive oil, castor oil and lard are also employed in
the production of special milling soap bases, a palm oil soap being
specially suitable for the production of a violet-scented toilet soap.

_Yellow Household Soaps._ (_a_) _Bar Soaps._--These are made from tallow
with an admixture of from 15-25 per cent. rosin. The best quality is
known in the South and West of England as Primrose Soap, but is
designated in the North of England by such names as Golden Pale,
Imperial Pale, Gold Medal Pale, etc. Tallow alone produces a very hard
soap of inferior lathering qualities; but rosin combines with alkali to
form a soft body, which, although not a soap in the strict sense of the
term, is readily soluble in water, and in admixture with the durable
tallow soap renders it more soluble in water and thereby increases its
lathering properties.

The rosin may be added to the soap-pan after a previous partial
saponification with soda ash, and removal of colouring matter, and
finally saponified with caustic soda lye, or, as is more generally
adopted, as a rosin change. The pan is opened with caustic soda lye and
saturation of the rosin takes place rapidly; when completely saponified
it is grained with salt, and the coloured lye allowed to deposit and
finally withdrawn.

The four operations already detailed apply to this soap.

Cheaper pale soaps may be made from lower grades of tallow and rosin and
are generally silicated.

(_b_) _Tablet or Washer Type._--A demand has arisen for soap of free
lathering qualities, which has become very popular for general household
use. This soap is usually made from a mixture of cotton-seed oil,
tallow, and cocoa-nut oil, with a varying amount of rosin. The tallow
yields firmness and durability whilst the other constituents all assist
in the more ready production of a copious lather.

As to what amount of rosin can be used to yield a finished soap of
sufficient body and satisfactory colour, this naturally depends upon the
grade of raw material at the soap-makers' disposal. Those fats and oils
which yield firm soaps, will, of course, allow a greater proportion of
rosin to