Allen— The Insulating Properties of Erinoid. 



353 



or a combination of both, but the greater drying out of sample 0, already 

 referred to, has apparently had no appreciable effect on the value of a. 



Whatever the causes of this characteristic, the latter becomes less and less 

 pronounced as the temperature increases. 



a.000 



iftoo 



ilooo 



11+00 



1200 



£ 1000 



loo 



10 



ao 



Co 



1° 



30 L.0 50 



Temp. Deg. Cent. 



Fig. 4. — The specific insulation resistance of white erinoid at different temperatures and different 



thicknesses. Curve A is for thickness 0-65 cm. ; £, 0-53 cm. ; C, 0-32 cm. ; D, 0-175 cm. 



Insulation resistance of erinoid at different temperatures for 

 different contact electrodes. 



Erinoid in a tubular form was tested at different temperatures with 



mercury electrodes, then with graphite, next with water, afterwards air-dried 



for a short time, and finally tested again with mercury as its electrodes. The 



results obtained for blue erinoid are given in Table 15. 



