say from red to blue, etc. The original color
always modifies that of the dye somewhat and it is best to experiment
first with a small portion of the dye and cloth. Rather dark shades are
apt to be most successful.

[Sidenote: Natural Dyestuffs]

Indigo for blue, madder for Turkey red, logwood with fustic for black,
cutch or gambia for browns on cotton are about all the natural dyestuffs
which are used to any extent commercially at the present time. The
artificial product alizerin, the active principle of madder, has about
superseded the natural dyestuff, and artificial indigo is gaining on the
natural product.

Linen is bleached and dyed in much the same manner as cotton, although
the process is more difficult. The process of bleaching weakens linen
more than cotton.

[Sidenote: Dyeing Woolen and Silk]

Woolen and silk may be dyed directly with a great variety of dyes
without the addition of a mordant, although they are often mordanted.
Both must be well washed or scoured before dyeing. When white or
delicate shades on woolen or silk are desired they are bleached. The
bleaching is usually done with sulphurous acid gas, the cloth or yarn
being exposed in a damp condition to the fumes of burning sulphur.

Were it not for the expense, hydrogen peroxide would be the ideal
bleaching agent for the animal fibers.

PRINTING

A great variety of colored designs are produced on the loom by using
different colored warp and filling yarns and different weaves, but in
all these the designs are easily made only in somewhat rectangular
patterns.

[Sidenote: Block and Machine Printing]

Print goods have doubtless evolved from the decoration of fabrics with
the brush. Block printing was first used, the design being engraved in
relief on blocks of wood. These are dipped in the colored paste, spread
thinly, and applied to successive portions of the cloth by hand. These
blocks are now replaced in the printing machine by engraved copper
rolls, the design being such that it is repeated once or a number of
times in each revolution of the cylinder. There is a printing roll for
each color of the design. Sometimes both the background and the design
are printed on the cloth, but the more common process is for the design
only to be printed on the cloth which may be dyed afterwards. In the
paste of the printed design there is some chemical which prevents the
portions printed from taking the dye, consequently these remain white or
a d