PURIFIED TEXTILE INSULATION 



249 



with humidity and with the degree of purity of the textiles. The 

 problem was finally solved by the development of the test equipment 

 shown in Figs. 6, 7 and 8. 



5 6 7 



TIME IN DAYS 



Fig. 4 — A.C. conductance of 50 ft. of twisted pair wire insulated with double servings 



of equal thickness. 



Figs. 6 and 7 show a heat-insulated glass tank of about one cubic 



foot capacity fitted with an insulating cover in which holes normally 



closed with stoppers are used to introduce the test samples. The 



humidity is maintained by means of sulphuric acid or a saturated 



17 



