5S4 



NATURE 



[August 7, 191 3 



PHOTOGRAPHS OF THE AURORA. 



AX important advance in the knowledge oi the 

 aurora is the outcome of the spring expedi- 

 tion to Bossekop, under M. Carl Stormer. This 



occasion has been most successful] 

 M. Carl Stormer has re- 

 cently but very briefly 

 communicated an account 



of the research to 



the Paris Aca- 



d e m y (Comptes 



rendus, June r6). 

 From Februan 



28 to April 1 ol 



the present ye ir 



t h e expedition 



secured 636 pairs 



o f simultaneous 



photographs oi the 



aurora at the two 



stations, namely, 



Bossekop and 



Store Korsnes, 



the latter station 



being' about 27 



kilometres to the 



north of Bosse- 

 kop. Of these 



photographs 450 



pairs are slated to 



he very satisfac- 

 tory and furnish 

 material sufficient 

 to compute with 

 a large degree of 

 accuracy the 

 fo r m , position, 

 and altitude of all 

 the principal 

 kinds of aurora 

 borealis. 



Further, exactly 

 at the same time 

 as I h e photo- 

 graphs of the 

 auro r : 1 w ere 

 taken, other 

 photographs, with 

 a prismatic 

 camera, were se- 

 cured. On these 

 latter photographs 

 can 1m- seen not 

 only the spectra 

 of the stars, but 

 several s u p e r - 

 posed impressions 

 of the aurora 1 

 corresponding to 

 different spectrum 

 lines. 



utilised, and 



As 



1910, 



Fig. r.— Photograph 'if the si 

 Europea 



1 taken on March 

 ,m Bossekop and Ko 



1 3, at ioh. 36m., Central 



expedition was undertaken to complete the work 

 done in the 1910 expedition, which was so fruitful 

 of results. The experience gained on the first 

 NO. 2284, VOL. 91] 



ia kinematograph 

 was employed to 

 try to secure the 

 changing phases 

 of the aurora : for the 

 most part the auroral 



images were too faint. On three occasions, how- 



