MOISTURE IN TEXTILES 243 



mined by the relative humidity. This conception is much like the 

 picture of acid or oil molecules standing as a film on a water surface, 

 with the polar end in the water. 



Some such function as equation 1 may apply since simply increasing 

 the length of the water chains will not cause a proportionate decrease 

 in the resistance. It seems evident from Fig. 5-a that small increments 

 of water might be expected to sufficiently lengthen water chains of 

 minimum separation so as to establish contacts between them along the 

 current path, but that larger increments of water are necessary to 

 accomplish the same result between more widely separated anchorage 

 points. This would explain the gradual change from the relation of 

 equation 1 at low moisture contents to equation 2 at intermediate 

 moisture contents. At some point along the humidity curve it is 

 conceivable that capillary condensation occurs in the pits so that at 

 progressively higher humidities the increasing cross-section of these 

 pits plays a more important part in current conduction than the 

 adsorbed chains of water molecules. This may explain why equation 

 3 is found to apply at highest humidities. 



Adsorption, however, appears to continue throughout the whole of 

 the humidity range, consistent with the hair swelling relations. Thus 

 it is shown that adsorption and capillary condensation need not be 

 considered separately but may go along together with a gradual 

 shifting in importance from one to the other in the current conduction 

 process. 



Evershed ^^ explained the decrease in resistance of a textile with 

 increasing applied potential as being due to elongation of pools of 

 water in the material under electrical stress forming more continuous 

 current paths. This deviation from Ohm's law may be explained also 

 as being due to the influence of increasing electrical stress upon the 

 oscillation of the free ends of moisture chains, bringing more of them 

 into orderly alignment along the line of applied potential, and estab- 

 lishing shorter current paths through the structure. 



The difference in electrical behavior of different textile fibers may 

 be illustrated by a comparison of the adsorption of moisture on cotton 

 and silk surfaces. From Astbury's pictures of the structure of protein 

 molecules as compared with cellulose molecules it appears that al- 

 though there may be more points per unit surface for moisture to 

 condense upon on protein surface, there are also possibilities of sepa- 

 ration of adjacent moisture chains in a manner similar to that discussed 

 for cellulose, and furthermore, there appear to be side chains of 

 hydrocarbons interspersed in the protein chain which may act as 

 barriers to the ready contact of adsorbed water chains on either side 



