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Dr. W. Hugging. 



auroraa fail to supply us with any adequate basis for a true concep- 

 tion of the electric forces in action on the sun. 



The phenomena of comets show not merely a highly electrical con- 

 dition of the sun's surface, but also the permanence of an electric 

 potential of the same kind, whether negative or positive.* Though 

 we do not know enough of what is taking place at the sun to define 

 the conditions which may cause the matter ejected from the sun's 

 surface to have a high electric potential of the same name, yet we 

 can see that broadly all the different actions which take place there, 

 and to which the electric disturbances are probably due, are parts 

 of one continuous process going on always in the same direction, 

 namely, the transference of energy from the interior to the photo- 

 sphere, and the loss of the energy there, in the radiant form. 



We must bear in mind that a strongly electrified state of the «olar 

 surface would not act as a force of repulsion upon discrete particles 

 of matter insulated from each other, such as exist in the tails of 

 comets and in the corona, unless these particles possessed an electric 

 potential of the same kind as the solar surface. If these particles 

 were in an unelectrified condition, the action of the sun would be one 

 of statical induction only, altering the original distribution of elec- 

 tricity over their surfaces, but powerless to change in any sensible 

 manner the positions of their centres of gravity in space, because 

 the attraction on one side of each particle would be balanced by the 

 repulsion on the other. 



* The sun's potential may he regarded as due to actions of some kind always going 

 on, or to a permanent charge received at some past time. The sun if once charged 

 with electricity of the same name would doubtless remain so charged, as Mr. Crookes' 

 experiments appear to show that a Tacuum would be a perfect insulator. 



If the sun has been charged with electricity of one name, we do not know how this 

 came about, though more than one probable conjecture might be hazarded. Some facts 

 mentioned further on as to the influence of Mercury and of Venus upon the coronal 

 matter would seem to make it very probable that these planets are permanently 

 charged with electricity of the .other name to that of the sun. If this should hold 

 good also of the more distant planets (we know nothing of the absolute potential of 

 the earth's surface), we should have the planets charged with one kind of electricity, 

 and the sun charged with the opposite electricity. As we have reason to believe 

 that the sun and the planets formed originally one cosmical mass, the question may 

 be suggested whether these changes of electricity of opposite names can have been 

 brought about in connexion with the separation of the matter which forms the 

 planets from that which exists in the sun. 



If we regard the sun as possessing an electric potential of one name, it is not 

 absolutely necessary to suppose the local electric disturbances which are spoken of 

 in the text. Electric disturbances are undoubtedly taking place there, and through 

 these the ejected matter might come to have a higher potential than it possessed as 

 forming part of the sun. Through these local disturbances some of the matter of 

 the corona might have sometimes a higher or lower potential of the same name, 

 and in this way might arise one of the varying conditions upon which the observed 

 changes in the corona depend. — August 20, 1885. 



