Mi M. .tit HI.] INVlSlMLi; LINKS IN TIIK SUN'S SPECTRUM. 



ent regions in succession, exposing the 

 >niMti\r surface to each for a suitable 

 li'iiirth of time. 



O 



In Fig. 10 I have given on the left 

 siilt- a representation of the larger Hues 

 of Fraunhofer; the right side gives them 

 as obtained on a daguerreotype plate 

 which has been iodized to a yellow, 

 brought by the vapor of bromine to a 

 red, and then slightly exposed to the 

 vapor of chloride of iodine. The pho- 

 tograph is so adjusted as to have its 

 lines by the side of those of Fraunhofer 

 which have the same name. It will be 

 seen that there are beyond the red ray 

 three extra spectral lines, which I have 

 marked a, j3, 7. These, however, I have 

 only occasionally found, for from the 

 general diminution of effect in that re- 

 gion they do not always come out in a 

 plain and striking manner. None of 

 Fraurihofer's lines in the yellow and 

 green are given, but G and its compan- 

 ions are very strongly impressed, as also 

 the group about i. But by far the most 

 striking in the whole photograph are 

 those marked H and k. Then passing 

 beyond the violet and out of the visible 

 limits of the spectrum, four very strik- 

 ing groups make their appearance. 



Fig. 10. 



To the first line of 

 each of these, in continuation of Fraunhofer's nomencla- 

 ture, I gave the designations M, N, O, P. In I there are 

 three lines, in M eight, in N three, in O four, and in P 

 five. 



Besides these larger groups, the photographs were 



