PURIFIED TEXTILE INSULATION 



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cotton has been found to be fairly satisfactory. This arrangement 

 gives galvanometer readings of the order of 2000 megohms for washed 

 silk and 1,000 megohms for washed cotton as compared with 12 

 meghoms and 5 megohms for unwashed silk and cotton respectively. 

 It is obviously necessary to maintain a high degree of insulation 

 resistance between the electrodes. This is accomplished by using 

 hard rubber for the stoppers in which they are mounted and preventing 

 surface leakage by coating the end of the stoppers with ozokerite wax. 



Fig. 8 — Electrodes on which samples are wound for test. 



The electrodes themselves are gold or platinum plated to prevent 

 oxidation or corrosion. Observing these precautions, it is possible 

 to obtain readings sufficiently consistent to distinguish not only 

 between washed and unwashed textiles but to determine differences 

 in degree of purification in various lots of washed textiles. 



The question may be asked as to why 75 per cent relative humidity 

 and 100 degrees Fahrenheit were selected for cotton and 87 per cent 

 relative humidity and 100 degrees Fahrenheit for silk. These values 

 were, within reasonable limitations, more or less arbitrarily selected 

 and further experience may show that some other values are preferable. 



