lowly under a strong illumination.

Materials which are not exposed directly to an intense and prolonged
illumination retain their whiteness for a long time, and hence dress
materials and hats which have been bleached with sulphurous acid
should be protected from the sun's glare when not in use.

223. The Removal of Stains. Bleaching powder is very useful in the
removal of stains from white fabrics. Ink spots rubbed with lemon
juice and dipped in bleaching solution fade away and leave on the
cloth no trace of discoloration. Sometimes these stains can be removed
by soaking in milk, and where this is possible, it is the better
method.

Bleaching solution, however, while valuable in the removal of some
stains, is unable to remove paint stains, because paints owe their
color to mineral matter, and on this chlorine is powerless to act.
Paint stains are best removed by the application of gasoline followed
by soap and water.

CHAPTER XXIII

DYEING

224. Dyes. One of the most important and lucrative industrial
processes of the world to-day is that of staining and dyeing. Whether
we consider the innumerable shades of leather used in shoes and
harnesses and upholstery; the multitude of colors in the paper which
covers our walls and reflects light ranging from the somber to the
gay, and from the delicate to the gorgeous; the artificial scenery
which adorns the stage and by its imitation of trees and flowers and
sky translates us to the Forest of Arden; or whether we consider the
uncounted varieties of color in dress materials, in carpets, and in
hangings, we are dealing with substances which owe their beauty to
dyes and dyestuffs.

The coloring of textile fabrics, such as cotton, wool, and silk, far
outranks in amount and importance that of leather, paper, etc., and
hence the former only will be considered here; but the theories and
facts relative to textile dyeing are applicable in a general way to
all other forms as well.

225. Plants as a Source of Dyes. Among the most beautiful examples
of man's handiwork are the baskets and blankets of the North American
Indians, woven with a skill which cannot be equaled by manufacturers,
and dyed in mellow colors with a few simple dyes extracted from local
plants. The magnificent rugs and tapestries of Persia and Turkey, and
the silks of India and Japan, give evidence that a knowledge of dyes
is widespread and ancient. Until recently, the vegetable world was
the source o