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BELL SYSTEM TECHNICAL JOURNAL 





where 125000 AU is taken as the mean diameter of the dry cotton 

 hair. 



According to Conins,'" the coefficient of hair diameter increase with 

 humidity is about 0.11 per cent per 1 per^cent R. H. Therefore, an in- 

 crease of 0.4 per cent in hair diameter is found at 0.4/. 11 = 3.6 per cent 

 R. H. From adsorption data (Fig. 7) by Urquhart and WilHams/^ 

 this relative humidity corresponds to between 1.1 per cent and 1.2 

 per cent moisture content. The difference in this value and that 



20 



30 40 50 60 70 



RELATIVE HUMIDITY IN PER CENT 



Fig. 7 — Moisture adsorption-lnimidity relation for cotton at 25° C 



