Bigelow — Magnetic Theory of the Solar Corona. 255 



according to the nature of the gas. If these rays were then 

 subjected to the lines of force of a strong magnetic field, the 

 following phenomena were seen : 



(1). If the magnetic lines extended through the rarefied 

 region, they illuminated the basal portions of the rays of light. 

 If these disappeared, as when the gas was made too rarefied, 

 they also appeared again when the field was strengthened. 



(2). The rays of light are strongest in a field of medium 

 strength. 



(3). They follow the direction of the magnetic lines of force. 



(4). When the lines of force are very dense and impinge at 

 right angles to the surface of the iron body, the rays of light 

 are thrust to one side. The polar collar of the magnetized 

 iron sphere, for example, was then entirely robbed of rays / 

 the light structure surrounds the pole in the form of a ruffle, 

 the inner boundary of which follows the same direction as the 

 lines offorceP 



Ebert makes an application of this valuable experiment to 

 an explanation of the aurora borealis and the solar corona. It 

 is evident that Pupin's experiment was incomplete, in that it 

 lacked the organizing effect obtained by plunging the body 

 emitting coronoidal electrical discharges into a magnetic field, 

 and that the special phenomena observed in the corona of the 

 sun are remarkably matched in all details by the forces pro- 

 duced through the combined action of electrical discharges in 

 a magnetic field. My original result that the polar region of 

 the sun is robbed of its rays, and that the coronal lines coin- 

 cide in direction with the lines of magnetic force, is thus veri- 

 fied by experiment, and this is explained by the well known 

 theory of the deflection of cathode rays in a vacuum tube 



under a magnetic field of force. The formula,* — = —==- , 



involves the theory alluded to, as can be seen by consulting 

 the references. The charged ions are deflected by a magnetic 

 field, and also by an electrostatic field. This argument, which 

 might be greatly expanded, carries with it the following con- 

 clusions, in my judgment : 



(1) The photosphere of the sun is the seat of powerful 

 electric discharges which ionize portions of its material, or at 

 least set free minute particles of matter charged with electricity. 

 These are repelled outward in a coronoidal radiation and give 

 the forms seen in the disorganized streamers. (2) The nucleus 

 of the sun must*" be the seat of a powerful magnetic field 

 whose axis is near that of the sun's axis of rotation, and whose 

 action upon the ions repels them from the polar zones, in 



* J. J. Thomson, Phil. Mag., Oct., 1897 ; J. Henry, Phil. Mag., Nov., 1898, etc. 



