THE EARTH A MAGNET. 43 



always observed to be accompanied by the exhibition 

 of the aurora in high latitudes, northern and southern. 

 Probably they never happen without such a display ; 

 but numbers of auroras escape our notice. The con- 

 verse proposition, however, has been established as a 

 universal one. "No great display of the aurora ever 

 occurs without a strongly-marked magnetic storm. 



Magnetic storms sometimes last for several hours or 

 even days. 



Remembering the influence which the sun has 

 been found to exercise upon the magnetic needle, the 

 question will naturally arise, Has the sun any thing to 

 do with magnetic storms ? We have clear evidence 

 that he has. 



On the 1st of September, 1859, Messrs. Carrington 

 and Hodgson were observing the sun, one at Oxford 

 and the other in London. Their scrutiny was directed 

 to certain large spots which, at that time, marked the 

 sun's face. Suddenly a bright light was seen by each 

 observer to break out on the sun's surface and to travel, 

 slowly in appearance, but in reality at the rate of 

 about 7,000 miles in a minute, across a part of the 

 solar disk. Kow it was found afterward that the self- 

 registering magnetic instruments at Kew had made at 

 that very instant a strongly -marked jerk. It was 

 learned that at that moment a magnetic storm pre- 

 vailed at the West Indies, in South America, and in 

 Australia. The signal-men in the telegraph-stations at 



