The Electrical Conductivity 



47 



J— ^£«fl— 



FIG.}. 



A — Cyrstal. B — Quartz Tubing. C — Cal. Chloride. 

 D — Tin Container. 



Diagram Showing Mounting of Calcite Crystal 



A guard ring was used to eliminate effects due to surface 

 conductivity. Later it was found that this precaution was not 

 necessary. The current through the crystals, which varied 

 from 10"'^ amperes to 10'" amperes, was measured by means of 

 a Dolazalek electrometer. The whole apparatus was carefully 

 screened electrostatically and precautions were taken to keep 

 the crystals and insulation dry. Calcium chloride was used as 

 a drying agent. 



The temperature was kept constant at any desired value 

 by placing the crystal in a DeKhotinsky thermo-constant 

 electrical oven. It was found that the temperature of this 

 oven when regulated did not vary more than .5 °C. The dia- 

 gram, Fig. No. 1 (A), shows the appratus assembled. 



