[boyle] 



TENSILE STRESS ON ELECTRICAL RESISTANCE 



179 



place. This would explain the low values for the specific resistance. Lt 

 IS hardly probable that the specific resistance does decrease at this stage 

 of stretching. 



In order to be sure of the temperature coefficient of this specimen 

 of Constantin a special deUermmation was made. The result showed that 

 the coefficient varied greatly at different temperatures, but at the tem- 

 pirature of the test wire in his work it was practically negligible, being 

 not more than .00001. with minus sign. 



DATA SHEET P. 



^ Constantin. 



Standard resistance used - 2.00218 - .000496 (t - 20° C.) 

 Temperature Coefficient of test wire = — .00001. 



'Extension caused by pulling out wire with the hand. Vaines given pro- 

 bably do not represent the correct Specific Resistance for these extensions. 



