SYSTEMS INTERMEDIATE 



379 



lies just below the saturation point. The specific conductance of the 

 saturated solution is 0.5047 X 10 4 ; or, almost precisely one half that of 

 mercury at 0. That the solutions of the metals in liquid ammonia at 

 these concentrations are metallic admits of no doubt. They exhibit all 

 the properties of metallic substances, both optical and electrical. A 

 brief consideration will show, indeed, that in these solutions the metal 

 possesses an exceptionally high conducting power compared with that of 



3.0 



CQ 



I 



o.s 



o.o 



7.S 



l.o 



2.9 To T.Z 74- 7*6 7.B 0.0 o.a. 0.4- o.e o.& 

 Log V. 



FIG. 66. Conductance of Concentrated Solutions of Sodium and Potassium in 

 Liquid Ammonia at 33.5. 



many metals. Obviously, if metallic conduction is due to the motion of 

 charged carriers, then two factors influence the conductance; in the first 

 place, the resistance which the carriers experience in their motion, and, 

 in the second, the number of carriers present in a given volume. In 

 comparing the conducting power of different metals, it is not sufficient 

 to merely compare their specific conductances. The concentration factor 

 should also be taken into account. If the specific conductance is divided 

 by the number of gram atoms per cubic centimeter, the ratio yields the 

 atomic conductance of the metal. The atomic conductance of a satu- 



