616 



TABLE 653.— ATMOSPHERIC-ELECTRIC DATA 



Air-conductivity 

 total 



X = X t + X- Land : 1 to 5 esu X 10"* Variations determined chiefly by 



local factors 

 Sea : 2.6 " " Variations small and chiefly ir- 

 regular 

 Free air Ratio of value at various alti- 

 tudes to that at surface 

 km 1 6 km 20 



3 " 8 9 " 38 



Ratio of positive 

 to negative 

 conductivity . . . 



Air-earth current 

 density 



X + /X. 



Land: 

 Sea: 



i = XP/30000 Land: 

 Sea : 



Density of small 

 ions : Positive . 



Negative 



Ratio of positive 

 to negative ionic 

 density 





Land : 

 Sea: 

 Land: 

 Sea: 



1.12 

 1.26 



7.0 

 11.0 



750 

 600 

 650 

 500 



esu X 10" 7 

 ions/cm 8 



(n+ + n.)/2 Free air Values at various altitudes 



2 km 1300 



4 " 1900 



5 " 2300 



p = n+/n. 



Land 

 Sea: 



1.23 

 1.23 



(continued) 



SMITHSONIAN PHYSICAL TABLES 



