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Page:Popular Science Monthly Volume 24.djvu/194

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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 perfect 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 accompanying this article. The originals of these sketches I made at the time the spots were visible, and they represent with approximate accuracy 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 during

PSM V24 D194 Hydrogen burst of a sun flare.jpg
Fig. 2.

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 observed as a small but extremely brilliant protuberance, that exhibited very marked displacement of the C-line toward the violet end of the