the Ions in Gases at Low Pressures. 565 



A 2 and B 2 represent diatomic molecules of these gases (Proc. 

 Camb. Phil. Soc. vol. x. p. 9). This result makes it probable 

 that the ionization of a gas in these cases results from the 

 splitting up of the atoms of the gas, rather than from a 

 separation of one atom from tbe other in a molecule of the gas. 



These results, taken in conjunction with the measurements 

 of the mass of the negative ion, suggest that the ionization of 

 a gas consists in the detachment from the atom of a negative 

 ion ; this negative ion being the same for all gases, while the 

 mass of the ion is only a small fraction of the mass of an 

 atom of hydrogen. 



From what we have seen, this negative ion must be a 

 quantity of fundamental importance in any theory of elec- 

 trical action ; indeed, it seems not improbable that it is the 

 fundamental quantity in terms of which all electrical pro- 

 cesses can be expressed. For, as we have seen, its mass and 

 its charge are invariable, independent both of the processes 

 by which the electrification is produced and of the gas from 

 which the ions are set free. It thus possesses the charac- 

 teristics of being a fundamental conception in electricity; and 

 it seems desirable to adopt some view of electrical action 

 which brings this conception into prominence. These con- 

 siderations have led me to take as a working hypothesis the 

 following method of regarding the electrification of a gas, or 

 indeed of matter in any state. 



1 regard the atom as containing a large number of smaller 

 bodies which T will call corpuscles; these corpuscles are equal 

 to each other; the mass of a corpuscle is the mass of the 

 negative ion in a gas at low pressure, i. e. about 3 x 10 -26 of a 

 gramme. In the normal atom, this assemblage of corpuscles 

 forms a system which is electrically neutral. Though the 

 individual corpuscles behave like negative ions, yet when 

 they are assembled in a neutral atom the negative effect is 

 balanced by something which causes the space through which 

 the corpuscles are spread to act as if it had a charge of posi- 

 tive electricity equal in amount to the sum of the negative 

 charges on the corpuscles. Electrification of a gas I regard 

 as due to the splitting up of some of the atoms of the gas, 

 resulting in the detachment of a corpuscle from some of the 

 atoms. The detached corpuscles behave like negative ions, 

 each carrying a constant negative charge, which we shall call 

 for brevity the unit charge ; while the part of the atom left 

 behind behaves like a positive ion with the unit positive 

 charge and a mass large compared with that of the negative 

 ion. On this view, electrification essentially involves the 

 splitting up of the atom, a part of the mass of the atom 

 getting free and becoming detached from the original atom. 



Phil. Mao. S. 5. Vol. 48. No. 295. Dec. 1899. 2 R, 



