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BELL SYSTEM TECHNICAL JOURNAL 



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RELATIVE HUMIDITY IN PER CENT 



Fig. 8 — Moisture adsorption intercepts for acetylated cottons indicating amounts 



of internal surface. 



8. Theory of Conduction of Electricity Through Cotton 

 It now appears possible to provide a more comprehensive theory 

 for the conduction of electrical current through the moisture paths in 

 a textile than has been suggested previously.^- ^ 



Below 1 per cent moisture content it is likely that equation 1 fails 

 to hold, due to obvious discontinuities in the moisture paths over 

 surfaces containing less than a monomolecular layer of water.* Above 

 1 per cent, it is not to be concluded, however, that a continuous 

 moisture film exists. It appears that some space is still available 

 between certain water molecules, and the space pattern of water 

 distribution is determined by the type of solid surface and the arrange- 

 ment of active points or zones upon which each water molecule is held. 

 In the case of cotton, such active points are considered to be hydroxyl 

 groups; for silk they may be amino or carboxyl groups or both, and 

 from Astbury's discussion ^^ of the chain structure of these two 

 materials it seems likely that their space patterns for moisture ad- 

 sorption are different. Furthermore, it is assumed that each of these 

 active points may be anchorage not only for a single water molecule, 

 but for a chain of such molecules, the length of the chain being deter- 



* It is of interest to note that if the linear portion of the curve shown on Fig. 3 

 is extrapolated to the insulation resistance axis, the insulation resistance correspond- 

 ing to this intercept is found at 0.3 per cent M. C. (see a — Fig. 3), this being of the 

 same order of magnitude as that estimated to cover fibril surfaces with a mono- 

 molecular layer, suggesting that the linear portion of the curve is specifically related 

 to moisture adsorption on the fibril surfaces. 



