The most reliable tests for a mixture of cotton and wool are chemical
or microscopic ones, but as these are not practical for the average
buyer, others must be sought. Wool has luster and “kinks;” the ends of
the threads are stiff and look rather wiry. When a sample is carried
home, burning will serve to distinguish between the two. Wool burns
slowly, chars, has an odor of burnt feather, goes out easily and leaves
a crisp ash; cotton burns quickly with a flame, with little odor and
leaves no ash.
A little practice in breaking the threads will help one to distinguish
between the two; the difference is not one that can be easily
explained, but the experienced housewife knows it well.
Fig. 2A shows a sample of all-wool cloth, of the class of worsteds
which cost seventy-five cents a yard. Fig. 2B shows a sample of
cloth of the same price, called by the clerk, all-wool, but which on
examination was found to have only four threads of wool to every twelve
threads of cotton. Fig. 2C shows this same cloth with the wool removed
by strong alkali, caustic potash, leaving the cotton. Fig. 2D shows the
wool left when the cotton has been ravelled out, or has been removed by
a strong acid solution.
Fig. 3 shows a sample of mohair in which the wool has been partly
removed, and the cotton warp is left. In this case the price is not
high, and because of the character of the cloth the mixture is a good
one, light, smooth, and clean. This cloth is not sold for all-wool, so
is not considered adulterated.
[Illustration: FIG. 3