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THE POPULAR SCIENCE MONTHLY. 



paralleled pageant on the sun. Changes were continually going on in 

 the shape and even the size of the spots, and in the configuration of 

 the different members of the groups — minor evolutions in the ever- 

 advancing column. New spots of small size made their appearance in 

 the neighborhood of larger ones ; and in one instance, at least, a per- 

 fect swarm of little spots broke out near one of the largest components 

 of the belt, as if the surface of the sun had been suddenly punctured 

 by huge needles. 



A very good idea of the appearance of the band of spots, and of 

 their progressive motion from east to west with the revolution of the 

 sun, as well as of the principal changes that took place in their form 

 and arrangement, can be obtained from the series of sketches accom- 

 panying this article. The originals of these sketches I made at the 

 time the spots were visible, and they represent with approximate ac- 

 curacy the appearance of the spots with a magnifying power of sixty- 

 five diameters. They do not, however, by any means show all the 

 details visible with such a power. With higher magnifying powers 

 the crowd of details in some of the larger groups was so great and 

 confusing as to defy the power of the pencil to represent them. Some 

 remarkable phenomena were also observed with the spectroscope dur- 



FiG. 2. 



ing this sun-spot display. When the huge group, seen near the left- 

 hand edge of the sun in Fig. 2, was just coming around the edge, its 

 approach was announced by an outburst of gas which M. Thollon ob- 

 served as a small but extremely brilliant protuberance, that exhibited 

 very marked displacement of the C-line toward the violet end of the 



