THE SPOTS ON THE SUN. 



157 



Lamont, of Munich, in 1850, was the first to announce that thesa 

 magnetic disturbances attain a maximum of frequency in about ten 

 years. Two years later, Sabine, Wolf, and Gautier, noticed the coin- 

 cidence of this period with that of the solar spots. And this coinci- 

 dence was more than general. There was a coincidence of maximum 

 spot-frequency with maximum of magnetic disturbance, and of mini- 

 mum with minimum, which compelled them to assert a causal connec- 

 tion between the two periods. Wolf subsequently proved that the 

 period of magnetic disturbance has the length of 11.11 years. 



But there is still more striking!; evidence of this connection. On 

 September 1, 1859, Mr. Carrington, an eminent English astronomer, 

 happened to be intently engaged in observing and mapping a group 

 of spots, when a sudden and most extraordinary outburst occurred, of 

 so startling a nature that, having noted the exact moment by his chro- 

 nometer, he hastily ran to call some one to see the exhibition with him ; 



Fig. 8. 



Spiral Solar Spot, or Cyclone, observed by Secchi. 



when upon returning, within 60 seconds, the whole spectacle had dis- 

 appeared. " The spots had travelled considerably from their first po- 

 sition, and vanished as two rapidly-fading dots of white light. In the 

 interval of five minutes, the two spots transvered a space of about 

 35,000 miles." He likens the appearance to that of a sudden conflagra- 

 tion. This was also independently seen at the same moment by Mr. 

 Hodgson, who says : " I was suddenly surprised at the appearance of 

 a very brilliant star of light, much brighter than the sun's surface, and 

 most dazzling to the protected eye. It lasted some five minutes, and 

 disappeared instantaneously." 



At the moment when the sun was thus disturbed, the magnetic 

 instruments at Kew exhibited the signs of great magnetic disturbance. 

 " It was found," says Dr. Balfour Stewart, " that a magnetic storm had 

 broken out at the very moment when this singular appearance had 



