ROUGH WAYS MADE SMOOTH. 



THE SUN'S CORONA AND 

 HIS SPOTS. 



ONE of the most important results of observations made 

 upon the eclipse of July 29, 1878, indicates the existence of a 

 law of sympathy, so to speak, between the solar corona and 

 the sun-spots. The inquiry into this relation seems to me 

 likely to lead to a very interesting series of researches, from 

 which may possibly result an interpretation not only of the 

 relation itself, should it be found really to exist, but of the 

 mystery of the sun-spot period. I speak of the sun-spot 

 period as mysterious, because even if we admit (which I 

 think we cannot do) that the sun-spots are produced in 

 some way by the action of the planets upon the sun, it 

 would still remain altogether a mystery how this action 

 operated. When all the known facts respecting the sun- 

 spots are carefully considered, no theory yet advanced 

 respecting them seems at all satisfactory, while no approach 

 even has been made to an explanation of their periodic 

 increase and diminution in number. This seems to me 

 one of the most interesting problems which astronomers 

 have at present to deal with ; nor do I despair of seeing 

 it satisfactorily solved within no very long interval of 

 time. Should the recognition of a sympathy between the 



B 



