Eclipses 



less and are independent in their evolution. 

 One of these parts is entirely gaseous; it appears 

 to form around the sun an atmosphere regular in 

 form, but flattened towards the poles, and its 

 luminous emission, seen through the spectro- 

 scope, is characterised by numerous bright lines. 

 A photograph obtained in Spain during the last 

 eclipse showed over one hundred and twenty of 

 them, including the lines of hydrogen, helium, 

 titanium, iion and magnesium. But the 

 spectium of the corona is further distinguished 

 by a radiation of its own; it is a very bright 

 green line, which puzzled all observers, because 

 they were unable to assign it to any known 

 body. This line is considered to characterise 

 a new body, coronium, and as the coronium 

 line is frequently observed in the higher regions 

 of the solar atmosphere, where even hydrogen 

 lines cease to be visible, one is inclined to believe 

 that this hypothetical body is a gas still lighter 

 than hydrogen. The gaseous corona would thus 

 consist of three principal gases hydrogen, 

 helium and coronium shot through with 

 metallic vapours. 



The study of the bright rays of the gaseous 



211 



