TELLURIUM CRYSTALS 
305 
the current through the crystal. A voltmeter was connected 
across the crystal, 'and the current regulated by an adjustable 
resistance in series with the crystals. The increase of the con- 
ductance curve with current is very similar to that shown in 
figure 13, showing decrease of current with temperature. 
Fig. 14. — Curves showing electrical properties of tellurium crystals. 
A series of tests was made to establish the question of light- 
sensibility, all of which showed that there was no change in the 
conductance of Tellurium crystals under the action of light. 
The Physical Laboratory, 
State University op Iowa. 
20 
