tance of the fabric.

=The tests of permanence of dyes on fabrics are as follows:=

=Washing Fastness.= Fabrics should stand mechanical friction as well
as the action of soap liquor and the temperature of the washing
operation. In order to test the fabric for fastness a piece should be
placed in a soap solution similar to that used in the ordinary
household, and heated to 131 degrees F. The treatment should be
repeated several times. If the color fails to run it is fast to
washing.

=Fastness Under Friction.= Stockings, hosiery yarns, corset stuffs,
and all fabrics intended to be worn next to the skin must be
permanent under friction, and must not rub off, stain, or run, that
is, the dyed materials must not give off their color when worn next to
the human epidermis (skin), or in close contact with colored articles
of clothing, as in the case of underwear.

The simplest test is to rub the fabric or yarn on white unstarched
cotton fabric. In comparing the fastness of two fabrics it is
necessary to have the rubbing equal in all cases.

=Resistance to Perspiration.= With fabrics coming in contact with the
human skin it is necessary in addition to fastness under friction that
they should withstand the excretions of the body. The acids of
perspiration (acetic, formic, and butyric) often become so
concentrated that they act on the fiber of the fabric.

In order to test the fabric for resistance, place the sample in a bath
of 30 per cent dilute acetic acid (one teaspoonful to a quart of
water) warmed to the temperature of the body, 98.6 degrees F. The
sample should be dipped a number of times, and then dried without
rinsing between parchment paper.

=Fastness against Rain.= Silk and woolen materials for umbrella
making, raincoats, etc., are expected to be rainproof. These fabrics
are tested by plaiting with undyed yarns and left to stand all night
in cold water.

=Resistance to Street Mud and Dust.= Ladies' dress goods are expected
to withstand the action of mud and dust. In order to test a fabric for
this resistance the sample should be moistened with lime and water
(10 per cent solution), dried, and brushed. Or sprinkle with a 10 per
cent solution of soda, drying, brushing, and noting any changes in
color.

=Fastness to Weather, Light, and Air.= Various people have attempted
to set up standard degrees of fastness--for every shade of color is
affected by the action of sun, light, and air--and as a result fabrics
t