NUCLEATION CONSTANTS OF CORONAS. 



expansion on exhaustion v l /v. Tables 26 and 27 contain corresponding 

 results for air energized by the weak radium at a distance D = 35 or 40 

 cm. from the fog chamber. The difference observed in the curves of 

 successive identical experiments was found to be referable to the wet 

 or dry condition of the inside of the glass walls of the fog chamber. 

 Freshly wet walls are apparently essential. 



TABLE 27. Dust-free wet air energized by weak radium acting from D = 4O cm. 

 Supplementary data. Bar. 76. 2 cm.; temp. 24 C. Dry glass walls. 



In table 28 the ionization is slightly intensified by affixing the radium 

 tube to the outside of the walls of the fog chamber. In table 29 there is 

 further intensification, obtained by acting upon the fog chamber with 

 the X-rays at = 50 cm. 



TABLE 28. Dust-free wet air ionized by weak radium (10 mg. 10,000 X) on glass fog 

 chamber. Bar. 74.9 cm., 75.0 cm.; temp. i7.7C. 



Fog limit below ^ = 0.7 56 at 18, equivalent to ^=1.22, equivalent to a drop 

 (adiabatically) of <?/>= 18.6 cm, (about ) at 76 cm., 2 cm. below Wilson's dp = 20. 5 cm. 



