BEYOND THE HORIZON. As the base surge com- 

 pletes its lateral spreading, the cloud, drained by 

 gravity of its water content, floats off with the 

 wind. During the first hour her northward progress 

 was easily watched by observers on surface vessels; 

 the cloud retained a slight orange tint, and ap- 



page 207 



peared somewhat larger than other clouds. By the 

 end of the second hour she was practically indis- 

 tinguishable from the countless clouds dotting the 

 horizon; and all attention reverted to the destruc- 

 tion in the Lagoon. Specially-equipped planes 

 were able to follow the cloud some time longer. 



