EXAMIN/ITION OF TEXTILE FiBRBS. 



83 



solution of hydrate of copper in ammonia, the cellulose 

 dissolves and swells up the cuticula into bubbles between 

 the twists of the fibre, while at the twists the cuticula con- 

 tracts, giving the characteristic beaded appearance shown 

 in Fig. 31, e. 

 Much of the cotton in textile goods has been subjected 



Fig. 32. — The Cotton-fibre. (After Hassack.) 200 diameters. 



to ,the process of mercerization, or immersion of the cloth 

 in a stretched condition in strong caustic soda solution. 

 Cloth thus treated is stronger, takes dyes better, and has a 

 closer, firmer texture and a fine glossy appearance. Under 

 the microscope the individual fibres appear as crinkly, 

 irregular cylinders instead of fiat ribbons and the central 

 canal is much shrunken. Sometimes the fibres are so 



