•230 



Mr. T. Gray on the Electric Resistance 



ratures as I could have wished; but they are sufficient to show 

 the general effect to which I wish to direct attention. In the 

 first two experiments the readings were taken according to the 

 first of the two methods described above; in the other two the 

 second method was followed. 





Experiment I. 





Temperature. 



Resistance. r 



Cemperature. 



Resistance. 



o 





o 



67 



14 x 10 10 



69 



.. 98xl0 10 



96-5 



127 xlO 9 



110-5 .... 



.. 34xl0 8 



109 



48 x 10 8 



127-5 .... 



.. 92xl0 7 



128-5 



13 x 10 8 



151 



.. 25xl0 7 



150 



30 x 10 7 



173 



.. 68xl0 6 



169 



67 x 10 6 



194-5 .... 



.. 22xl0 G 



194-5 



22 x 10 6 





Experiment II. 





Temperature. 



Resistance. 



Temperature. 



Resistance. 



15 .... 



.. 12xl0 12 







25 



.. 57xl0 n 







35 



.. 26xl0 n 







43 



.. 12xl0 n 



38 



.. 27xlO n 



48 



.. 72xl0 10 



47-5 .... 



.. 136 xlO 10 



59 



.. 27xl0 10 



58-5 .... 



. 47 x 10 10 



78-5 .... 



.. 47xl0 9 



76-5 .... 



. 12 x 10 10 



100-5 .... 



.. 79xl0 8 



97 



. 25 x 10 9 



120 



.. 18xl0 8 



116 



. 57 x 10 8 



140 



.. 48xl0 7 



137 



. 136 x 10 7 



163 



.. 12xl0 7 



160-5 .... 



. 29 x 10 7 



198 



.. 16xl0 6 



196 



.. 37xl0 6 



220 



.. 57xl0 5 



210 



.. 20xl0 6 



244 



.. 28xl0 5 



237 



.. 52xl0 5 



*243-5 .... 



.. 40xl0 5 







258 



.. 38xl0 5 



258 



.. 38xl0 5 





Experiment III. 





Temperature. 



Resistance. 



Temperature. 



Resistance. 



94° .... 



.. 24xl0 9 



o 



93 .... 



.. 20 xlO 10 



99 



.. 169 xlO 8 



108 .... 



.. 57xl0 9 



136 



.. 121 xlO 7 



128 .... 



.. 124 xlO 8 



163 



.. 226 xlO 6 



157 .... 



.. 181 xlO 7 



183-5 .... 



.. 169 xlO 6 



176 .... 



.. 52xl0 7 



205 



.. 57xl0 6 



195 .... 



.. 79 xlO 6 



214 



.. 53xl0 6 



214 .... 



.. 53xl0 6 



* The temperature was maintained about 244° for an hour : at the end 

 of that time the glass showed a marked increase of resistance. 



