288 FROST— OBSERVATIONS OF THE ECLIPSE. 



and designated by some as the " heliosaurus." As may be seen 

 from the slide, the prominence is visible only in the H and K lines 

 of calcium. If present at all in the other emissions it is too weak 

 to impress the plate. On the contrary, the quiet prominence at 

 position angle 297° (= north latitude 40°) appears also in the H/?, 

 Hy, and Hh lines, and the prominence at position angle 51° (^ north 

 latitude 26°) is bright in helium D^ as well as in the hydrogen series. 



The low prominence or uncovered photosphere at position angle 

 240° (^ south latitude 17°) shows a remarkable extension into the 

 ultra-violet, the bright group between wave-lengths 3350 and 3390 

 A being especially strong. This prominence is an origin of coronal 

 streamers, as Professor Barnard has shown in his paper on page 222,. 



The continuous spectrum of the corona is so strong that it masks 

 the narrow rings due to the bright coronal lines at wave-lengths 

 5303, 4231 and others. 



Yerkes Observatory, 

 April 18, 1919. 



