304 



Scientific Proceedings, Royal Dublin Society. 



The straight line law is again well illustrated by this sample D. This 

 line runs nearly parallel to that of A and B, and shows that for the range of 

 temperature used it is superior to them in insulation resistance. 



Table 8. 



Sample E. 



Thickness 0T5 cm. 



Fig. 6 shows that the straight line for sample E, which is of Berlin 

 manufacture, is practically coincident with that for D, which is also of German 

 make. The larger contact area of this sample made it possible to obtain a 

 roughly representative value for such a low temperature as 17° C. The line 

 for E is represented by the small circles associated with the line drawn for D. 



