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THE POPULAR SCIENCE MONTHLY. 



QUIESCENT PROMINENCES 

 Scale, 75,000 miles to the inch. 



Fig. 15. 



Fig. 12. 



Clouds. 



Fig. 13. 



Filamentary. 



Fig. 14. 



Plumes. 



Horns. 



precise nature of the action which produces this effect it would not be 

 possible to assign at present ; but it is worthy of note that the obser- 

 vations of the eclipse of 1871, by Lockyer and others, rather favor 

 this view, by showing that hydrogen, in a feebly luminous condition, 

 is found all around the sun, and-at a very great altitude — far above 

 the ordinary range of prominences. 



The eruptive prominences are very different, consisting usually of 

 brilliant spikes or jets, which change their form and brightness very 

 rapidly. For the most part they attain altitudes of not more than 

 20,000 or 30,000 miles, but occasionally they rise far higher than even 



