74 



VAPOR NUCLEI AND IONS. 



(4-inch cock) gives an excess of ions, whereby the graphs for I and II in 

 the region of lower coronas are consistently distinct. I will pass this over 

 here, as it needs additional investigation. 



That the limit of efficiency has been reached for plug-cock apparatus 

 is specifically proved by the fact that the same large green-blue-purple 



Fig. 34. Disposition of apparatus in case of fog chamber (F) and vacuum 

 chamber (V ), connected by 2-inch pipes and 2$-inch stopcock. 



corona terminates the observations, no matter whether the nuclei are 

 relatively large, as in case of the ions and intense X-radiation,or relatively 

 small, as in case of the colloidal nuclei. This is differently proved in the 

 work with alcohol, in Chapter IV. 



It is somewhat hard to understand why the efficiency should terminate 

 abruptly, with a certain number of nuclei per cubic centimeter, no matter 



