382 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



negative carrier of the different metals is the same appears, therefore, 

 amply justified. 



The temperature coefficient of sodium solutions in liquid ammonia 

 has been measured. In Table CLII are given values of the resistance 

 of fairly dilute sodium solutions from the boiling point of liquid ammonia 

 up to 85C. In the last column are given values of the mean percentage 

 temperature coefficient of these solutions over various temperature inter- 

 vals referred to the resistance at 33. 7a 



TABLE CLII. 



TEMPERATURE COEFFICIENT OF DILUTE SODIUM SOLUTIONS. 



A(l/fl) 

 t R X * 



33 124.3 



13 85.7 2.25 

 + 17 43.4 4.69 

 + 48 28.2 5.34 

 + 85 15.6 9.00 



It is seen that at low temperatures the temperature coefficient of the 

 conductance of these solutions is approximately 2 per cent, and as the 

 temperature increases the temperature coefficient increases markedly 

 reaching a value of 9 per cent for the interval between 45 and 85. 

 This behavior of the metal solutions in liquid ammonia is in striking 

 contrast to that of normal electrolytes dissolved in this solvent. At 

 ordinary concentrations, the conductance of these solutions passes 

 through a maximum in the neighborhood of room temperatures, the 

 conductance decreasing with increasing temperatures above this point. 

 It is obvious that the factors involved in the temperature coefficients of 

 the metal solutions are very different from those involved in solutions of 

 ordinary electrolytes. It is difficult, in the present state of our knowl- 

 edge, to state to what the high value of the temperature coefficient is 

 due. However, since in fairly dilute solutions the conductance is due 

 primarily to the negative electron more or less associated with ammonia, 

 it is possible that the high value of the temperature coefficient at higher 

 temperatures is due to an increase in the mean speed of the negative 

 carriers as a result of a diminution in the size of the solvent envelope 

 with which the negative electrons are surrounded. 



While at low concentrations the temperature coefficient of the metal 



T * Kraus, loc. cit. 



