Mr Kleeman, The Unstable Nature of the Ion in a Gas. 279 
where c, and ¢ are given by equations (3) and (5) respectively. 
If 8 is small in comparison with (8 —a)V,, V. is small in com- 
2 
parison with (@—a)J, and in that case 
2 (18 Caer 
C= (aga th) Bose 
The effect of the unstability of the positive ion is then as if an 
ac , ok. 
additional number of free ions equal to ——~*—— were drawn 
; V.(8 —a) 
through the gauze. 
In conclusion I wish to express my thanks to Prof. Sir J. J. 
Thomson for his kind interest in these experiments. It should 
also be mentioned that the expense of the principal apparatus 
was defrayed out of a grant of the Royal Society. 
