A a meeting of the Videnskapsselskapet in Kristiania Jan. 28 1916 
Prof. Kr. BIRKELAND sent in for printing a treatise with the tittle: Are the 
Solar Corpuscle Rays that penetrate into the Atmosphere of the Earth 
Negative or Positive Rays? !. 
A literal translation of this work into French was previously sent by 
Prof. BinkELAND to Archives des Sciences physiques et naturelles in Genf, 
where it was published in the.issues of Jan. 15 and Febr. 15 1916. 
As my complete answer to the attacks made by Prof. BIRKELAND in 
the above treatise will be published in the Genf Archives? I need here 
only give the results: — 
I) Prof. BiRKELAND’S criticism of the manner in which I imagine the 
auroral draperies may be formed, has no foundation in his experi- 
ments. On the contrary, the facts which he refers to, confirm the 
mathematical theory. 
2) Prof. BIRKELAND's idea concerning the formation of auroral drape- 
ries seems to me to be poorly founded and highly improbable. As 
far as I can ascertain no research has yielded facts that permit the 
bold conclusions drawn by Prof. BIRKELAND. 
3) As regards the question whether the Aurora Borealis is caused by 
positive or negative particles, my statement which has been so very 
severely criticized by Prof. BIRKELAND, was made with great caution, 
as I said no more concerning this special occurrence of Aurora 
Borealis on March 11 1913 than the following: Jt thus appears to 
be proved that the Aurora was caused by positively charged electric 
particles. I willingly admit the possibility of the action on the mag- 
netic instruments being caused by corpuscle currents outside the 
atmosphere, and not by the Aurora, although Prof. BIRKELAND’S 
arguments do not seem convincing to my mind. The conclusive de- 
cision can only be obtained by further research in more cases. 
1 Printed June 16, 1916 as No. 1 of Videnskabsselskabets Skrifter. Math. Naturv. Klasse 
1916. 
9 Sur les draperies d'Aurores boréales, Reponse à M. Kr. Birkeland loc. cit. April 1917, 
IO pages with one figure. 
