242 Mr. G. Owen on the Discharge of 
From Tables III., IV., and diagrams 3, 4,5 the curves 
given in diagram 6 have “been drawn. These curves show 
Diagram 4. 
7:5 X 10-9 ampere. 
Current 1 
the variation of the current with the pressure under a 
potential of —200 volts. The values of the current at the 
higher temperature have been divided by 50 in order to 
make it possible to plot both curves on the same diagram. 
Discussion of the Results represented by the Curves in 
Diagrams 3, 4, 5, 6. 
It will be noticed from the curves that the leak under any 
given potential (say 200 volts) increases at first as the pres- 
sure is diminished. This, however, does not take place in- 
definitely, for ata pe essure of 2°5 mm.at the lower temperature, 
and of about 5°2 mm. at the higher temperature, the leak 
attains a maximum value. The leak now diminishes with 
decreasing pressure until a pressure of about 0°035 mm. is 
reached. ” Exhausting still further produces but little dimi- 
nution in the current. The leak was approximately saturated 
only at pressures greater than 200 mm., and less than about 
one-tenth of a millimetre. The curve at a pressure of 141 mm. 
