224 ANNUAL REPORT SMITHSONIAN INSTITUTION, 195 2 



Cotton, silk, and wool have been the fibers used almost exclusively 

 for fabrics until a few decades ago. Rayon and acetate silk were 

 then introduced. These are both chemical modifications of cellulose, 

 derived usually from cotton or wood. In spite of the fact that they 

 lack many of the desirable properties of the natural fibers, particu- 

 larly wet-strength and recoverability of the original shape upon 

 drying, these fibers have been widely accepted and have supplemented 

 or in part replaced cotton and silk. Acetate fabric possesses a lux- 

 urious "feel" and drapes in soft, lustrous folds. Acetate blends re- 

 markably well with other fibers. Just recently it has been amiounced 

 that a rayon has been made in which the basic structure has been 

 so modified that the resulting product has the wet-strength exhibited 

 by natural fibers. If this is authentic, one of the greatest steps for- 

 ward in rayon manufacture since its inception will have been achieved. 



About 15 years ago nylon, a strictly synthetic fiber, made by com- 

 bining very simple molecules into a complex one similar to those 

 nature furnishes us, made its appearance. Chiefly' because of its 

 rapid-drying properties, its durability, and its resistance to fungi 

 and insects, it has found many applications for which natural fibers 

 are not suitable. Natural silk, for which nylon is a substitute, has 

 never recovered its prewar status. The brilliant researches in Japan 

 extending over a period of 40 years, when the silkworm was nurtured 

 and pampered until he produced an egg-shaped instead of peanut- 

 shaped cocoon with a filament twice as long as formerly and of double 

 strength, will be of no avail by the time the synthetic chemist has 

 had a decade or more of additional experience. The uses for nylon 

 have become so numerous that the demand cannot be met by present 

 production facilities. Newer synthetic fibers have appeared on the 

 market— for example, Orion, Acrilan, Dynel, which resemble oup 

 another somewhat in properties and are all based on the same simple 

 chemical, acrylonitrile. These fabrics are utilized particularly for 

 seat covers, curtains, and filter cloths in industry. They are also 

 suitable in the apparel field because of their smart appearance, long 

 wear, and easy laundering. Still another synthetic fiber is Dacron, 

 which resists wrinkling, water, and moths as does no other fiber. Suits 

 made of Dacron go through rainstorms without losing their crease 

 and can be cleaned with soap and water without losing the original 

 shape after drying. 



Rapid drying is effected because the threads do not absorb water 

 and drying consists merely in the evaporation of surface moisture. 

 But this nonabsorption of moisture leads to a certain amount of dis- 

 comfort, particularly in hot weather. Consequently, closely woven 

 fabrics for shirts and undergarments have in large measure been re- 

 placed by those with a sheer or open weave. To find a fiber that will 



