PLATE III. 



Fig. 1. — The K line on the solar dlslc and in the chromosphere at the limb 

 (radial slit). The Itrisht reversals (Ko) are due to the tlocenli. Where facuL-e 

 are present the continuons s])ectrnm is more or less strengthened. 



Fig. 2.- — Reversals of the 11 and K lines in the electric arc, showing the de- 

 crease in width from the inner (dense) to tlic outer (rare) calcium vapor. 



Fig. 3. — Minute calcium Hocculi, resembling the granulation of the photo- 

 sphere. The squares are lU" of arc on a side. 



148 



