212 3Ir, William Hiigrjins [Feb. 20, 



ditions under wliicli these cometary appearances take place, but the 

 hypothesis which seems on the way to become generally accepted, 

 attributes them to electrical disturbances, and especially to a re- 

 pulsive force acting from the sun, possibly electrical, which varies as 

 the surface and not like gravity as the mass. A force of this nature 

 in the case of highly attenuated matter can easily master the force 

 of gravity, and as we see in the tails of comets, blow away this thin 

 kind of matter to enormous distances in the very teeth of gravity. 



If such a force of repulsion is experienced in comets, it may well 

 be that it is also present in the sun's surroundings. If this force be 

 electrical it can only come into play when the sun and the matter 

 subjected to it have electric potentials of the same kind, otherwise the 

 attraction on one side of a particle would equal the repulsion on 

 the other. On this theory, the coronal matter and the sun's surface 

 must both be in the same electrical state, the repelled matter negative 

 if the sun is negative, positive if the sun is positive. 



The grandest terrestrial displays of electrical disturbance, as seen 

 in lightning and the aurora, must be of a small order of magnitude 

 as compared with the electrical changes taking place in connection 

 with the ceaseless and fearful activity of the sun's surface, but we do 

 not know how far these actions, or the majority of them, may be in 

 the same electrical direction, or what other conditions there may be, 

 so as to cause the sun's surface to maintain a high electrical state, 

 whether positive or negative. A permanence of electric potential of 

 the same kind would seem to be required by the phenomena of 

 comets' tails. 



If such a state of high electric potential at the photosphere be 

 granted as is required to give rise to the repulsive force which the 

 phenomena of comets appear to indicate, then considering the gaseous 

 irruptions and fiery storms of more than Titanic proportions which 

 arc going on without ceasing at the solar surface, it does not go 

 beyond what might well be, to suppose that portions of matter 

 ejected to great heights abave the photosphere and often with velo- 

 cities not fa removed from that which would bo necessary to set it 

 free from the sun's attraction, and very probably in the same electric 

 state as the photosphere, might so come under this assumed electric 

 repulsion as to be blown upwards and to take on forms such as those 

 seeu in the corona : the greatest distances to which the coronal 

 streamers have been traced are small as compared with the extent of 

 the tails of comets, but then the force of gravity which the electrical 

 repulsion would have to overcome near the sun would be enormously 

 greater. 



It is in harmony with this view of things that the positions of 

 greatest coronal extension usually correspond with the spot zones 

 where the solar activity is most fervent ; and also that a careful 

 examination of the structure of the corona suggests strongly that the 

 forces to which this comjikx and varying structure is due have their 

 seat iu the sun. Matter repelled upwards would rise with the smaller 



