from Hot Platinum in Air at Low Pressures. 59 



The unit of pressure is -^^ mm. and that of current is 5'6 x 10~ 4 

 electrostatic units per second. 



The numbers in the above table represent a linear relation 

 between the current and the pressure. Thus the leak consists 

 of two parts, one of which is proportional to, and the other in- 

 dependent of, the pressure. Similar results were obtained with 

 a potential of + 80 volts on the filament. The part of the leak 

 which is independent of the pressure was found to be nearly inde- 

 pendent of the potential over a range from 40 to 200 volts. 



