TEMPERATURE COEFFICIENT OF ICE. JOHNSTONE. 143 



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

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

 to be the case in every curve 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" 1 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 R t is the specific resistance 

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



perature will be -p- x . For the temperature co-efficient 



u t 



curve, see Fig. 9. 



f 



i- 



I"- 



C*r* 



-.! 



7~. > 7/sr/7V<? T "Csss*' C^'O CT*~r~sc 



FIG 0. 



i. Kjohlraufch, F., Phj-^ico-Chem. Men.ure.mcrt8. 



