PLATE VIII. 



Fro. 1. — Higher K, level. Slit at HOo^. Tliouirli taken before the photographs 

 reproduced in Plate \'II, this itictiire further einpliasizes the differences noted at 

 lower levels. The fact that tlu> clianiics ar(> proij;ressive largely eliminated the 

 time element, which nnght otherwise he susix'cted of causing the oliserved dif- 

 ferences. As a matter of fact, these tlocculi are (piiescent and slowly changing, 

 dilTering very decidedly from ernptiv(> i)henomena. 



Fm. 2. — K., level. Slit at .''>0?)H.S. Mere the calcium vapor is very hrilliant 

 and covers a larger area. The photograph contains distinct evidence of dark 

 alisorhing masses at higher levels. I'erhaps the best instance of this is the dark 

 tongue which runs somewhat north of west from the small spot south i)receding 

 the largest one of th(> group. This tongue seems to form a part of an extensive 

 dark area, which comi)letely surrounds the bright flocculi of the group. 



153 



