922 Dr. R. D. Kleeman on Disintegration of an Ion 



Carbon dioxide. 

 Press. 4 mm. 



Pi 



Air. 

 •ess. 3 mm. 



Field 

 per cm. 



Neg. 

 current. 



Pos. 

 current. 



3 



Field 

 per cm. 



Neg. 

 current. 



Pos. 

 current. 



520 



8 



' 520 



7 





560 



11 



4 



560 



8 





600 



24 



5 



' 600 



12 





640 



48 



6 



640 



25 



8 



680 



120 



20 



660 



40 



10 



720 



324 





680 



1200 



18 









690 



L 



25 









696 





L 



We have assumed that the number of ions drawn through 

 the gauze is practically independent of the electric field when 

 it is large. This can be easily proved to be the case. Thus 

 it can be calculated that the electric field in the region where 

 the ions are made is roughly about jqVo °^ the ne ^ between 

 gauze and plate. Since the pressure of the gas in the 

 chamber is of the order 1 cm., the order of the velocity of the 

 ions in this region is 50. The ions after they are made are 

 therefore subject to recombination only for a period of *1 of 

 a second, since on the average they have to pass over a 

 distance of about 5 cm. The coefficient of general re- 

 combination is approximately proportional to the pressure, 

 and at a pressure of 1 cm. therefore about '01 that at 

 atmospheric pressure. The chance of an ion combining with 

 an ion of opposite sign is therefore '001 of its chance at 

 atmospheric pressure. Now when air at atmospheric pressure 

 is ionized by X-rays till a stationary condition is reached and 

 the ionizing agent cut off, it has been found in one particular 

 case that the ionization decreased from 186 to 106 in -45 of 

 a second or about to one half in *5 of a second. The ionization 

 per c.c. in the experiments described in this paper was much 

 smaller than the foregoing. It follows, therefore, that the 

 loss of ions by general recombination below the gauze in 

 these experiments was less than *1 per cent, and therefore of 

 negligible magnitude for fields of the strength used. 



But since the ions were produced by a particles, the 

 effect of initial recombination has to be considered. This 

 species of recombination is largely due to the fact that the 

 ions are produced only along the path of each a. particle, and 



