522 POPULAR LECTURES AND ADDRESSES. 



This result, it seems to me, is absolutely conclusive 

 against the supposition that terrestrial magnetic 

 storms are due to magnetic action of the sun ; or 

 to any kind of dynamical action taking place 

 within the sun, or in connexion with hurricanes 

 in his atmosphere, or anywhere near the sun outside. 



It seems as if we may also be forced to conclude 

 that the supposed connexion between magnetic 

 storms and sun-spots is unreal, and that the seem- 

 ing agreement between the periods has been a 

 mere coincidence. 



We arc certainly far from having any reasonable 

 explanation of any of the magnetic phenomena of 

 the earth; whether the fact that the earth is a 

 magnet ; that its magnetism changes vastly, as it 

 does from century to century ; that it has some- 

 what regular and periodic annual, solar diurnal, 

 lunar diurnal, and sidereal diurnal variations ; and 

 (as marvellous as the secular variation) that it is 

 subject to magnetic storms. The more marvellous, 

 and, for the present, inexplicable, all these subjects 

 are, the more exciting becomes the pursuit of 

 investigations which must, sooner or later, reward 



