F. TF. Very — Nebulosity around Nova Persei. 59 



agreement with that to be expected under the influence of 

 gravity and magnetic repulsion combined, and is thus a strong 

 argument in favor of the theory. 



Assuming the radius of the nova to be 10,000,000 km., I find 

 the magnetic repulsion upon the ions at the surface of the star 

 mast be about 100,000 times as great as the attraction exerted 

 upon them by the star's mass. At a distance (for the outer 

 ring) of about a billion kilometers, however, gravitation 

 becomes the more powerful, and the velocity of recession 

 begins to diminish. The distance of course depends upon the 

 dimensions of the excessively minute corpuscles. 



In order to discover whether the forces required to commu- 

 nicate the observed motion are within the limits of possibility, 

 and are able not only to separate and expel but also to guide 

 the ions, I have taken the dimensions given for the corpuscles 

 by Professor J. J. Thomson, and have combined them with 

 my computation of the mass of the nova." I find that the com- 

 puted magnetic repulsion (in excess of gravity) could generate 

 a velocity of nearly 100,000 km. per sec. in the first second, if 

 it were able to exert its full power. Hence it does not seem 

 improbable that velocities as great as this, or even three times 

 as great (i. e., having the velocity of light) could be started by 

 electric oscillatory discharges in the huge masses of intensely 

 heated gases erupted from the nova, ionizing them, and prepar- 

 ing material for dissipation and control by the powerful 

 magneto-electric impulses started at the same time. 



I suppose the corpuscles or negative ions to be ethereal 

 vortices, and consequently must make the further assumption 

 that they are diamagnetic, in order to account for their being 

 repelled magnetically. 



At this point it is possible to descend from the sky to the 

 earth. A laboratory experiment by Goldstein, f which has never 

 been fully explained, furnishes a connecting link in favor of 

 my last assumption. This experimenter subjected a vacuum- 

 tube in which diamagnetic sodium and magnetic nitrogen 

 glowed together under the electric discharge, to the action of 

 a powerful magnetic field, with the result that only the nitro- 

 gen glowed, the diamagnetic substance having been entirely 

 cleared away by repulsion. Free diamagnetic substances must 

 tend to accumulate in regions of least magnetic potential, 

 and the diamagnetic hydrogen of the gaseous nebulae possibly 

 maps out such regions. 



I will now allude very briefiy to the difficulties encountered 

 by the hypothesis. The attraction or repulsion on a magnetic 

 body is a differential one, and in a uniform field increases with 



* Astronomische Naehrichten, No. 3771, clviii, 33, 1902. 

 fWied. Ann., xii. 261, 1881. 



