256 Mr. G. Owen on the Discharge of 
respectively) to show that the carriers of the negative elec- 
tricity from a Nernst filament at low pressures are the 
“ corpuscles.” 
Diagram 9. 
Percentage of Leak stopped. 
°4 6 8 10 {2 14 /é 
Current through Magnet. 1 ampere=59 lines/sq. cm. 
As is seen from the curves, the effect of the magnetic field 
approximates more and more to a saturation value as the 
magnetic field is increased. This is probably due to the 
ionisation not being confined to the gas in contact with the 
filament. Hven at these low pressures there will be a certain 
amount of ionisation by collision; and so a few ions will start 
towards the electrodes from a distance much smaller than 
3°5 mms. These ions will therefore require much stronger 
magnetic fields to deflect them before they reach the electrodes. 
A curve showing this saturation effect would also be obtained 
if a small percentage of the corpuscles were shot out of the 
filament with a considerable velocity. 
With a potential of — 200 volts on the filament 99:7 per cent. 
of the negative leak was stopped by a magnetic field of a little 
over 800 lines per sq.cm. There is thus every reason for 
believing that the carriers of the negative electricity from a 
Nernst filament at low pressures are all corpuscles without 
any admixture of heavier particles. 
On subjecting the positive leak to a magnetic field not the 
slightest diminution in the current could be produced by the 
