348 BABCOCK. 



heater switch was thrown as nearly as possible at the exact end of the 

 minute indicated in the first column. The temperature of the stand- 

 ard ohm, the standard cell, and the oil bath, were recorded at the be- 

 ginning and end of each measurement. The potential drop readings 

 given in the third and fourth columns, were made as rapidly, as possible 

 during the heating period, but not at definite time intervals. The 

 values of Rq, Ri, R2, and R3, were obtained by plotting column 2 

 against column 1, and drawing the best initial and final lines. The 

 values given were then read from the plot. The time intervals given 

 in connection with these resistance readings, are the elapsed times 

 between successive pairs of readings, as is indicated by their location 

 in the table. 



