TEMPERATURE COEFFICIENT OF ICE. JOHNSTONE. 



14S 



A temperature-resistance curve is sliown in Fig. 8, and it 

 will be observed that it is nearly expotential. This was found 

 to be the ease in every cur^^e of six, plotted. 



The specific resistance of the ice was found by multiplying 

 the resistance of the ice between the '^potential-terminals" by 

 the ''cell-constant'''^ of the tube. 



To determine the temperature co-efficient of the resistance 

 at different temperatures, the cotangent of the temperature- 

 resistance curve, (Fig. 9), was determined graphically at 

 different temperatures, and this was divided by the resistance 

 of the ice at this point. Thus if Rt is the specific resistance 

 at temperature t then the temperature co-efficient at this tem- 

 perature will be —rz- 

 curve, see Fig. 9. 



dt 



For the temperature co-efficient 



jfi^{TCj::^/yr^4S^S, 



Fig 9. 



). Kohlrausch, F., Phjsico-Chcm. Ment^urenicrts. 



