1542 The Cornell Reading-Courses 



Adulterations 



In spite of abundance of raw material and ease of manufacture, cotton 

 fabric is often adulterated. Inferior qualities are made to appear of good 

 grade by being sized with starch, gums, and china clay. 



Imitations of linens and of mercerized cottons are often placed on 

 the market and sold for the same prices as are charged for genuine 

 material. In order to obtain the mercerized appearance, ordinary cotton 

 is passed between two heavy rollers that give a luster similar to the luster 

 of the more durable fabric under the name of which it will be sold. 

 Such a process is called calendering. 



Chemicals used in bleaching and in stamping designs on cotton fabrics 

 often weaken the fiber to such- an extent that cloth may become almost 

 worthless if it is allowed to lie on the shelf for some time before being 

 used. This is more likely to be true of cheap grades of cotton, since less 

 care is used in their manufacture than in the manufacture of fine cloths 



Tests for adulteration 



When cloth that has been adulterated is held to the light the meshes are 

 seen to be filled with sizing. 



If sizing has been used to a great extent, a piece of cloth rubbed briskly 

 will show white powder. 



If cloth is thoroughly boiled for a 'few minutes the filling will dis- 

 solve out. 



Boiling and rubbing will remove the calendered polish from the so- 

 called linens and mercerized cottons. 



If a sample that is thought to have been weakened by the action of 

 bleaching chemicals is torn, its weakness will be easily detected. 



Suggestions 



Cotton fiber is covered by cotton wax, which serves as a protective 

 coat and renders cotton material very slow in absorbing water. For 

 this reason cotton dish-towels are unsatisfactory. If a cloth to absorb 

 moisture is desired, it must be made of a fiber that is not water- 

 repellent. In absorbent cotton the wax has been removed. 



Cotton is light in weight and inexpensive, and affords a most desirable 

 fabric for general wear. It is especially desirable for undergarments 

 and house dresses, since it is not impaired by frequent laundering. 



Starch is absorbed by the cotton fibers as readily in the process of laun- 

 dering as at the time of manufacture. It is therefore possible to keep 

 the garments as fresh as when new. 



