I916. No. I. ARE THE SOLAR CORPUSCLE RAYS NEGATIVE OR POSITIVE? 



near enough to the earth for their existence to be ascertained in our 

 atmosphere. It would be of high interest if closer observations of the 

 phenomena occurring on the morning side of the earth could bring to 

 evidence such positive solar rays, but I have never yet obser\'ed anj-thing 

 of this kind. 



Before I go into detail with the discussion of aurora theories and 

 demonstrate the error in Prof. Stormer's reasoning. I shall communicate 

 shortly some new facts which will threw a very clear light upon the 

 whole question concerning the emanation of corpuscle ra3s from the sun 

 into space. 



Registration cf the Intensity of Zodiacal Light. 



2. I am just able to give some experimental results firom simultaneous 

 researches made in North and South Africa by me and my assistant 

 K. De\-ik on the Zodiacal light, results which most conclusively point to 

 the existence of a permanent and powerful equatorial emission of corpuscle 

 rays from the sun in the form of a rather flat circular disc, such as I have 

 supposed in my theon.' of zodiacal light, being conducted thereto espe- 

 cially by experimental analogies ^ 



From a physical point of view it is most probable that these new 

 solar rays are neither exclusively negative nor positive raj'S, but of 

 both kinds. 



The observations of zodiacal light mentioned above aimed at regi- 

 strating photographically its intensity to see whether we could detect 

 variations in it. The registration was performed by letting the zodiacal 

 light shine upon an Elster and Geitel photo-cell which was connected 

 to a Cremer wire electrometer which has recently been used to study 

 variations in the intensity of the light of stars. A complete report of my 

 researches will be given later when they are finished, and I will not to 

 any extent anticipate the results, but shall only reproduce on a reduced 

 scale one of the first curves registered at Helwan on i6th March 191 5 in 

 quite clear weather, from 7** 19 to 8^ 35 Standard Eg>-ptian Time. 



Figure i. The curve is not a very good one, but it shows fine oscil- 

 lations in the intensity of the zodiacal light. The white cur\e on a black 

 ground is produced by the shadow of the electrometer-wire, a platin wire 

 having a thickness of about two thousandth parts of a millimetre. A half- 



' Se , Aurora Polaris' pp. 6ii— 631 and Comptes Rendus de rAcadémie des Sciences, 

 Paris 6 February 191 1, ao July 1914, 31 August 1914 and 14 September 1914. the 

 two last notes in collaboration with Mr. Skolem. 



