CARL STORMER [No. 5, 1915] 



Explanation of the plates. 



Plate I. Mr. Oxaal's photographs of the corona, tåken with an amateur 

 camera. Plates: AgfaChromo; exposure, 5 — 8 seconds. Magnified 

 8 times. 



Plate II. The first three upper photographs from Laksfors, tåken with 

 an auroral photographic apparatus (lens, Ernemann kinostigmat. 

 Plates: Agfa Chromo and Chromo isolar) hy dr. Henie and myself. 

 Exposure about 1 second. Magnified 8 times. The other photographs 

 tåken by B. J. Birkeland at Svenningviken, with the same objective, 

 on Agfa Chromo plates. Exposure 1 and 4 seconds. 



Plate III. Nos. 7— 13 and 37—41 of the film. Objective, Ernemann kino- 

 stigmat. Exposure about one third of a second. These and the 

 following photographs tåken by Mrs. Størmer. Magnified 8 times. 



Plate IV. Nos. 42-45 and 63-69 of the same film. Magnified 8 times. 



Printed 3Uth August, 1915. 



