RECTIFYING PROPERTY IN SILICON AND SELENIUM. 



135 



of current than those given in figure 2. In the case of A + 

 the change of curvature is quite plainly seen. In this 

 figure the unit of current is 0*0009 ampere, and the unit 

 difference of potential 0*18 volt. By adding the ordinates 

 of A+ and B-, and A— and B-f , a current voltage curve 

 similar to that of Curve II, fig. 1, is obtained, (allowing for 

 the change of axes), the potential drop in the silicon itself 

 being negligible compared with that across the junctions. 

 The presence of the apparent minimum conductance on the 

 positive side is due to the form of the A+ curve. 



Fig. 3. 



7 . 



5 ~^L 



5 ■■ —/^- 



<* -y/- 



J y/- 



Similar curves were obtained on several occasions with 

 the aid of the potentiometer, and also when a gold leaf 

 electrometer was employed in the measurement of the 

 differences of potential. 



It seems natural to associate the phenomena observed 

 with the absorption or evolution of heat which occurs when 

 currents cross junctions of different metals. The Peltier 

 effect with silicon is very great, the thermo-electric height 



