Mercerized cotton is cloth produced by the action of a strong alkali on cotton fiber rinsed under tension. The process of mercerization is generally carried on while the fiber is still in the yarn. Mercerized cotton is actually stronger than cotton which has not been so treated. The characteristic twist of the cotton fiber is taken out, and the cell-wall is thickened by contraction. The result is a stronger fiber, a long slender cylinder which reflects the light, rather than a flat twisted, ribbon-like filament. The cellulose of the fiber is changed into another kind of chemical substance which has a much greater affinity for dye substances; therefore, beautiful colorings may be found in mercerized cotton materials.

The cost of producing a high grade of mercerized cotton, it has been stated, is about three times that of unmercerized cotton; consequently if a piece of this material is offered at a very low price, it is well to test it for true mercerization before buying. This may be done by thoroughly washing a sample or exposing it to friction and the weather. The gloss of properly mercerized material will not disappear on hard wear or laundering.

An imitation of mercerized cotton may be made by the action of very heavy and very hot cylinders on ordinary cotton cloth. This imitation will not withstand friction or laundering.

* Opus cit.