COTTON FIBER SCIENCE — PALMER 475 



keg, that is to say if they were uniformly long or short, or thick- 

 walled or thin- walled, appraising the quality of tlie cotton in a bale 

 might be fairly simple. But this is never the case. Always the mass 

 of fiber is a conglomerate of many, if not all, of these diverse proper- 

 ties, commingled in a myriad of permutations and combinations. 

 The quality of the mass is governed by the proportions which fibers 

 of these different characteristics are of the whole, by the influence 

 which each proportion exerts upon the properties of the manufactured 

 textile, and by the physical interaction of fibers of one type upon 

 those of other types. In spite of all efforts to achieve uniformity in 

 production, cotton actually comes to market in an incredibly wide 

 range and diversity of qualities, which have to be accurately iden- 

 tified and described. 



How tremendous, percentagewise, are the differences in and between 

 individual cotton fibers, invisible though most of them are to the eye 

 and impalpable to the touch, may be appreciated from the following 

 observations, reported by Dr. Robert W. Webb of the United States 

 Department of Agriculture to the National Cotton Congress at Waco, 

 Tex., in 1940 : 



The overall cross section of cotton fibers varies from as low as 26 square 

 microns to as high as 1,164 square microns, or a range based on the minimum 

 of 4,377 percent. 



The range of wall thickness in cross section varies from as little as 0.35 

 micron to as high as 15.5 microns, or a range of 4,328 percent. 



Lumen width varies at least from 0.35 to 12 microns, or 3,328 percent. 



The major axis of the lumen varies from as low as 0.5 micron to as much 

 as 40 microns, or 7,900 percent. 



The cross-sectional shapes of cotton fibers vary almost as much as the size 

 and wall thickness. 



The soundness of the cellulose varies greatly as indicated by fluidities rang- 

 ing from 2 to 50 rhes (2,400 percent), copper number from 0.2 to 1.5 (650 per- 

 cent), and alkali solubility from 2 to 7 percent (250 percent). 



Wax content varies from 0.5 to 10.0, or a range of 1,900 percent. 



Of fibers in the mass, Dr. Webb added : 



The proportion of thin-walled fibers varies from as low as 6 percent to as high 

 as 77 percent, or a range of 1,183 percent. 



The color ranges from the most delicate of creamy whites to the deepest sort of 

 yellow stain, chroma units being as low as 0.6 and as high as 3.20, or a range of 

 433 percent. 



Fiber bundle strength varies from 40,000 lbs. per square inch (of cross section) 

 to as high as 120,000 lbs. per square inch, or a range of 200 percent. Strength 

 values have been found to be as low as zero in some deteriorated cottons. 



Moreover, every ounce of raw cotton is composed of not one or two 

 or several different fiber lengths but, in fact, a multitude of fiber 

 lengths intermingled in various proportions, the length and length- 

 variability factors of which appreciably affect the utilities and values 

 of different cottons. Even the fibers from a single seed show a char- 



