A BELT OF SUN-SPOTS. 



181 



in it ; there was the great spot, often of singular outline, accompanied 

 outside its shadowy borders by one or more swarms of minute black 

 specks pitting the white photosphere in the most extraordinary fash- 

 ion ; there was the huge group, visible even to the unassisted eye, and 

 consisting of half a dozen or more large spots intermingled with 

 smaller ones whose number seemed to defy counting, and enveloped 

 in a penumbral cloak of becoming amplitude ; there, near the edges of 

 the disk, were the crinkling lines and heaped-up masses of faculte, the 

 mountainous hydrogen - flames which marked the places where the 

 intensest solar action was going on — in short, there was a panorama in 

 which every variety of sun-spot seemed to be passing in a gigantic pro- 

 cession across the disk. And what a procession it was ! — ^long enough, 

 nearly, to reach from the earth to the moon and back again three 

 times ! 



But the most extraordinary feature of this great solar display was 

 the linear arrangement of the spots making a belt, or band, that half 

 encircled the sun ; there was also a noticeable regularity in the distances 

 separating the groups composing this singular belt, and this peculiarity 

 increased the likeness to a procession which must have impressed every 

 observer who beheld the gradual march of the sun-spot army across the 



Fig. 1. 



solar disk. It was like watching a parade of masqueraders ; each 

 company of spots had its own characteristic and conspicuous make-up, 

 and each kept its place in the line at a nearly invariable distance from 

 the group in front of it and the one that followed. 



The separate spots and groups did not, however, present an unva- 

 rying appearance. There was change as well as variety in this un- 



