RESIDUAL WATER NUCLEI. 



105 



THE PERSISTENCE OF WATER NUCLEI IN SUCCESSIVE EXHAUSTIONS. 



65. Standardization with ions. A curious behavior appeared in an 

 attempt to standardize the coronas by aid of the ions due to gamma 

 rays penetrating the fog chamber. These were obtained from a sealed 

 sample of radium of strength io,oooX and weighing 100 mg. The coronas 

 were produced by successive exhaustions of the same value, the fogs 

 being dissipated by evaporation as soon as possible. The data given 

 in the above way in table 45 show an enormously rapid initial loss. To 

 obtain large coronas, the exhaustion to catch the ions was higher (drop 

 of pressure 3p 3 = 22 . 6) than to catch the water nuclei resulting from the 

 evaporation of fog particles (^3 = 17.1). Hence, in the two cases 

 dp 3 /p = 0.293, volume expansion v 1 /v = i.28, and dp 3 /p = o.22j, V 1 /v = 

 i .20, whence nX io~ 3 = o. 268s 3 and nX io~ 3 = o. 2I55 3 . 



80 



FIG. 33. Residual water nuclei obtained from evaporation of fog particles precipitated 

 upon ions. Curve (a) shows number of nuclei computed and observed found in 

 successive identical exhaustions ; curve (6) the corresponding relations of nucleation 

 n and coronal diameter s; (c) the corresponding behavior of phosphorus nuclei 

 compared with the ions. 



