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BELL SYSTEM TECHNICAL JOURNAL 



(a) CROSS SECTION 



SLIP SPIRAL 



PIT SPIRAL 



(b) SIDE VIEW SHOWING PIT SPIRAL REVERSALS 



Fig. 4 — The fiber structure of cellulose. 



(a) An idealized cross-section of the cotton hair. The domino-like blocks shown 

 in cross-section are arranged according to Ball's conception. 



(b) The spiral arrangement of these domino-like blocks or fibrils is shown, 

 together with the separating pits in the wall, and the slip-spiral effect along the fibrils. 



Obviously these conventional type figures do not represent the true shape of the 

 cotton of commerce, but they approximate the shape during the growth period, 

 before the boll is opened. As the hair dries out, the central lumen collapses and the 

 hair twists. 



