CHAPTER VI. 

 ON POSSIBLE ELECTRIC PHENOMENA IN SOLAR SYSTEMS AND NEBULAE. 



128. The Sun. The series of experiments that I have made with a magnetic globe as cathode in 

 a,arge vacuum-box, for the purpose of studying analogies to the zodiacal light and Saturn's ring, have 

 k to discoveries that appear to be of great importance for the solar theory. 



We have already several times had occasion to give various particulars regarding the manner in 

 \\ ch these experiments were carried out. It is by powerful magnetisation of the magnetisable globe 

 trt the phenomenon answering to Saturn's rings is produced. During this process, polar radiation and 

 di'uptive discharges at the equator such as that shown in fig. 2473 (which happens to be a unipolar 

 di'harge) may also occur, if the current intensity of discharge is great. If the magnetisation of the globe 



a Fig. 247. b 



be -educed (or the tension of the discharge increased) gradually, the luminous ring round the globe will 

 be reduced to a minimum size, after which another equatorial ring is developed and expands rapidly 

 Hi; 247 b). It has been possible for the ring to develope in such a manner that it could easily be de- 

 incstrated by radiation on the most distant wall of my large vacuum-tube (see fig. 217). The correspond- 

 in; ring would then have a diameter of 70 cm., while the diameter of the globe was 8 cm. 



It is a corresponding primary ring of radiant matter about the sun that in my opinion can give 

 an efficient explanation of the various zodiacal light-phenomena. In the above-mentioned experiments, 

 it seen how the rays from the polar regions bend down in a simple curve about the equatorial plane 

 of ic globe, to continue their course outwards from the globe in the vicinity of this plane. An aureole 

 is ^reby produced about the magnetic globe, with ray-structure at the poles, the whole thing strongly 

 resnbling pictures of the sun's corona. 



Rarefied gases, rendered luminous by similar discharges from the sun, would first emit a light of 

 the own, and then diffuse that of the sun. 



It is well known that the spectrum of the corona contains above all a brilliant ray of coronium 

 /. =5304, and besides this there is a faint continuous spectrum, probably due to reflected solar light. 



If the sun's corona is of an electric origin such as we have here assumed, we might perhaps 

 ex] ct to see an enormous ring of light about the sun every time the earth, during an eclipse of the 



Birkeland. The Norwegian Aurora Polaris Expedition, 19021903. 84 



