Allun — The Electrical Resistance of Porcelain. 



291 



the resistance was found to be 129 x 10 6 megohms, and 0-385 x 10 6 megohms 

 at the latter temperature. 



The present paper deals with the insulation resistance of samples of 

 porcelain in various forms at different temperatures, ranging from about 

 80° C, or lower in some cases, to about 250° C, or sometimes 300° C. 

 A description of these samples is given in the following list. 



List of Samples tested. 



3 b 2 



