Cathode Fall from Hot Carbon. 



207 



In fig. 7 I have plotted three curves (for different currents 

 (0) in the same units) showing the very sudden diminution 

 m cathode-fall as soon as the temperature of the cathode 

 exceeds a certain value which is higher for larger currents. 



Fig. 7. 



These are in entire agreement with the results published in 

 my previous paper (loc. cit.), and need not be further dwelt 

 upon here. It is often difficult to trace the values of the 

 cathode-fall round this sharp bend in the curve. 



In conclusion, I have much pleasure in acknowledging nay 

 gratitude to Professor J. J. Thomson for the kindly and Sug- 

 gestive interest which he took in the carrying out of these 

 experiments. 



