Smithsonian Report, 1910. — Deslandres. 



Plate 1, 









I 



1f^ 



' ' ^:?^gf -•?'■•' 



^.b. 



Upper Ks laj-er of calcium. 



1?,90^, P,N, 



•-JKWP' 





1^ 







P.S.'X 



Mean K2 layer of calcium. 



Spectroheliograms of September 18, 1908. 



(Negatives.) 



