1870.] DOUGLAS— ON OBSERVATIONS OF THE SUN. 137 



ation of this puzzling phenomenon has been given independently 

 by Dr. Gould. But Dr. Curtis believes this appearance to be due 

 to excessive deposition of silver in the photographic plate from 

 vicinity to the bright protuberance. His experiments in proof of 

 this would be conclusive had not the appearance been noticed by 

 the most uninitiated observer when watching the eclipse. A 

 carpenter asked Capt. Ashe what the notches (not a bad expres- 

 sion) in the moon were. 



SPECTROSCOPIC OBSERVATIONS. 



Spectroscopic observations were made by Professor Young, who 

 was stationed at Burlington, Iowa. He observed nine bright 

 lines, the number noted by M. Bayet at the previous eclipse, 

 though they do not correspond in position. Two, if not three, of 

 the lines are indisputably those of hydrogen, and several others 

 nearly correspond with iron lines. In the following table I give 

 a list of the lines observed, and Professor Young's remarks. The 

 middle column I am responsible for. 



Lines Observed Coincidences 



by and Remarlcs- 



Prof. Young. Nearest Conespondence. 



C. A hydrogen Hue Dazzling iu brightness. 



1017.5. . . .Xear double D — Sodium. .Bright, but not equal to C. 



1250.2 1250.4. — Iron Very faint ; position onl}^ estimated, 



and extending apparently beyond 

 the protuberance, and thought to 

 be a coronal line. 



1350.2. . . .1351.1. — Iron Like the preceding. 



1474 1473.9.— Iron A little below E ; conspicuous, but 



not half as bright as 1017.5. Like 

 the two preceding, supposed to 

 extend into the corona. 



F Hydrogen Xext to C in brightness. 



2602.2 2301.7.— Iron A little fainter than 1474 ; position 



determined by micrometrical 

 reference to the next. 



2796 Hydrogen? A little below H 8 ; in brightness, 



between 1017.5 and 1474. 



H 8 Hydrogen. . - Somewhat brighter than 1474. 



B Supposed to have been overlooked 



Prof. Harkness, at Des Moines, had taken every precaution to 



ensure accuracy in the record of his observations. He noted six 



lines in the protuberances, and one of the same lines in the 



corona. As might be expected, while he found the different 



protuberances to possess essentially the same constitution, he 

 TOL. V. I E'o. 2. 



