Fig. 15. Variation in computed air-earth current density with change in latitude 

 (Note conspicuous departure during fog, mist, and haze from April-June curve; 

 figures in circles denote number of observations included in each point) 



Fig. 16. Wind force (Beaufort) and direction and condensation-nuclei content of 

 the air from measurements aboard the Carnegie , cruise VII, between Hamburg 

 and Reykjavik 



174 



