344 C. Bar us — Vapor Nucleation in the Lapse of Time. 



the radius of but "038 under the given conditions, is equiva- 

 lent to a rise of temperature of 1° C. of the air within the fog 

 chamber or to 2000 more available nuclei according to the 

 above figure. 



3. Another suggestion. — The increment of about 2000 

 nuclei per degree of temperature under the conditions given 

 may also be looked on as a parallel to what occurs in case of a 

 radiant field like that produced by the X-rays. One may 

 regard ionization as a state of dissociation sufficiently advanced 

 to set free electrons and from this point of view equivalent to 

 a very high degree of temperature. One may thus expect a 

 passage of the vapor nuclei of wet dust-free air into the ions 

 through a continuous gradation of nuclei, and in fact they 

 always occur together. 



Brown University, Providence, E. I. 



