76 



Mr. J. X. L 



[Recess, 



spot period is approached. Moreover I suspect that the chromosphere has 

 lost somewhat of its height. 



I append a list of the bright lines, the positions of which in the chro- 

 mosphere I have determined absolutely, with the dates of discovery, remark- 

 ing that in the case of C and F my observations were anticipated by 

 M. Janssen : — 



October 20, 1863. 

 October 20, 1868. 

 October 20, 1SGS*. 

 December 22, 1863. 

 March 14, 1869. 



C. 

 F. 



near D. 

 near G. 

 h. 



D. February 28, 1869. 

 Barium. 



1989-5t. March 14, 1S69. 

 2031-2. July 5, 1869. 



Magnesium and included line. 



Iron 



t 



Bright line 



r 



Bright line 



February 21, 1869. 



Other Lines. 



1474. 



June 6, 1869. 



1515*5. 



June 6, 1869. 



1529 5. 



July 5, 1869. 



1567*5. 



March 6, 1869 



1613-8. 



June 6. 



18670. 



June 26. 



1871*5. 



>» 



2001 5. 



yy 



2003-4. 



M 



20540 



July 5. 



line, very delicate. ... J 



I have seen other lines besides these at different times ; but I do not 

 include them, as their positions have not been determined absolutely. 



I refrain from dwelling on this list at present, except to point out that, 

 taking iron as an instance, and assuming that the iron-lines mapped by Ang- 

 strom and Kirchhoff are due to iron only, 1 have only been able, up to the 

 present time, to detect 3 lines out of the total number (460) in the spec- 

 trum of the lower regions of the chromosphere, — a fact full of promise as 



* [Hydrogen ? — G. G. S.] 

 f This reference is to Kirch toiFs 



