MISCELLANEOUS EXPERIMENTS. 



49 



The region of positive ions should begin at about dp/p = o.^i cm., but 

 neither curve shows the slightest suggestion of any increase in nucleation, 

 though the drop in pressure has been intensified to an extreme case. Fog 

 chambers of the above type thus refuse to admit the separate occurrence 

 of positive ions. To this extent, therefore, the statement that negative 

 ions only are captured would be justified. 



f40r 



.PC .5>Q .2fl .3/ .20 .00 OA o/r 



r,O fwy c?V/ c2l .JUj cJt/ Or i)J 



FIG. 16. Absence of evidence for the region of positive ions beyond dp/p = o.j > i t 

 in case of a plug-cock fog chamber. Aperture _S in terms of the exhaustion ratio 

 8p/p. 



TABLE 1 6. Endeavor to find the region of positive ions in radium curve. 



