!5 2 



VAPOR NUCLEI AND IONS. 



as if a moisture gradient from the foil nearest the sodium to that more 

 remote were permanently maintained. In such a case there would be 

 slight but unequal precipitation of vapor on the two foils, in an apparatus 

 passing from warm to cold, and persistence would be due to freezing. 

 The only other explanation is the possibility of charges on the very cold 

 glass and on other insulators which can not be earthed. 



95. Mean daily ionization. As in the preceding case, the observations 

 were now averaged for single days. The results are given in detail in table 

 52. If given in the charts with the number of ions in thousands per 

 cubic centimeter laid off vertically, very little that is new may be 

 taken from these figures, and they are therefore omitted. They serve, 

 however, as a basis for the monthly ionizations which follow, and in 

 comparing the ionizations with the nucleation of the atmosphere these 

 charts are useful. Thus, it would be difficult to detect synchronism 

 in August, September, October, November, December; but from the 

 middle of January to the end of February suspicions of this kind would 

 be justified. 



Table 52. Mean daily ionizations corresponding to table 51. 



