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Scientific Proceedings, Royal Dublin Society. 



B being the resistance of the sample in megohms. In the case of sample E a 

 mean value is given, the expansion of the long length, about 37 cms., of 

 mercury being appreciable. 



As the accuracy of the leakage method depends upon the insulation 

 resistance of the test being independent of the voltage, it was necessary to 

 investigate whether this was so or not. 



A limited demonstration of this is the agreement of the galvanometer and 

 megger methods, the former dealing with voltages below 120, while the 

 latter subjects the test to 500 volts. Another indirect method is to show 

 whether the leakage-curves are logarithmic or not. 



The agreement between megger and galvanometer methods was generally 

 fairly good, the closest agreement found being given in Table I for sample A. 



Table 1. 

 For sample A. 



A comparison of the three methods is given in Table 2 for sample D, and 

 by graphing a and temperature, the agreement will be found satisfactory. 



