GREAT SUN SPOTS. 



307 



even the hideous groaning of the earth-throe sur- 

 passed a millionfold by what takes place within every 

 square mile of that disturbed region. 



One cannot wonder if many students of science are 

 eager to find out the real meaning of the sun spots, to 

 learn how they are generated, and to solve the secret 

 of that strange law which brings them in undulations 

 ten or twelve years long over the surface of the sun. 

 Still less can one wonder if many should be attracted 

 by theories associating terrestrial phenomena, not in 

 general (as they must assuredly be associated) but in 

 detail, with the periodicity of solar disturbance. It 

 has been shown that the earth as a whole responds to 

 the solar action displayed in sun spots. There can 

 scarcely be any doubt that the connection long since 

 indicated by Sabine between the phenomena of ter- 

 restrial magnetism and the condition of the sun's 

 surface with respect to spots is a real one. Not 

 magnetic relations simply, but others which have only 

 been associated within recent times with magnetism, 

 as the occurrence of auroral displays, &c., have been 

 clearly associated with the general condition of the 

 sun's surface on the one hand, and with the outbreak 

 of specific sun spots on the other. True, the great 

 solar storms recognised, when mighty masses of glowing 

 gas have been flung forth in the form of prominences, 

 have occurred without any simultaneous auroral or 

 magnetic disturbances on the earth. But these are 

 side issues, literally. The solar energy is there directed 

 not towards the earth, but at a right angle or there- 



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