nnin matters, etc.

Each dyer should make himself a pattern-book into which he should enter
his tests, with full particulars as to how they have been produced at
the side.

It is important that a dyer should be able to make comparative dye
tests to ascertain the relative strength of any two, or more samples of
dyes which may be sent to him. This is not difficult, but requires
considerable care in carrying out the various operations involved.

Of each of the samples of dyes 0.5 gram should be weighed out and
dissolved in 100 c.c. of water, care being taken that every portion of
the dye is dissolved before any of the solution is used in making up the
dye-vats. Care should also be taken that the skeins of yarn or swatches
of cloth are exactly equal in weight; that the same volume of water is
placed in each of the dye-pots; that the same amount of sulphate of soda
or other dye assistants are added; that the quantities of dye-stuff and
solutions used are equal; in fact, that in all respects the conditions
of dyeing are exactly the same, such, in fact, being the vital
conditions in making comparative dye tests of the actual dyeing strength
of several samples of dyes.

After the swatches have been dyed they are rinsed and then dried, when
the depth of shade dyed on them may be compared one with another. To
prevent any mistakes, it is well to mark the swatches with one, two,
three or more cuts as may be required.

It is easier to ascertain if two dyes are different in strength of
colour than to ascertain the relative difference between them. There are
two plans available for this purpose--one is a dyeing test, the other is
a colorimetric test made with the solutions of the dyes.

=Dyeing Test.=--This method of ascertaining the relative value of two
dyes as regards strength of colour is carried out as follows: A
preliminary test will show which is stronger than the other. Then there
is prepared a series of dye-vats--one contains a swatch with the deepest
of the two dyes, which is taken as the standard; the others, swatches
with the other dye, but containing 2, 5 and 10 per cent. more dye-stuff,
and all these swatches are dyed together, and after drying a comparison
can be made between them and the standard swatch and a judgment formed
as to the relative strength of the two dyes. A little experience will
soon enable the dyer to form a correct judgment of the difference in
strength between two samples of dye-stuff.

=Color