Jan., 1916] Electrical Behavior of Porcelain and Glass 



89 



taken up on reapplication of the e. m. f. without any dis- 

 crepancy. If a half hour elapsed the first values would be 

 somewhat larger than when the e. m. f. was withdrawn. 



In some cases after application for a half hour in one direc- 

 tion the battery was reversed. The effect of this was to have 

 the impressed e. m. f. of the batteries acting in the same 

 direction as the previously generated back e. m. f. The time 

 current curve showed this boosting effect, the initial values of 

 the current were larger and the time taken for the curve to 

 attain the flat portion was much longer. 



I.S 



13 



30 



35 



■^S 



■So 



Time Jn THinutes 



This boosting effect was apparent even when the specimen 

 was cooled to room temperature and reheated. The reversal 

 was effected in two ways: First, by reversing the battery; 

 Second, by taking the specimen out after cooling and turning 

 it end for end. This latter process had the effect of reversing 

 the specimen only leaving the terminals unaltered. The 

 effect was the same and the effect of previous polarization was 

 unmistakable. 



Figures 5 and 6 are companion curves for Figure 4 and are 

 introduced for the purpose of showing the retention of the 

 polarized state. Figure 4 is the first run made in a glass 

 cylinder which, so far as I had means of knowing, had never- 

 been treated electrically. 



