164 Mr. J. Norman Lockyer. 



Magnesium. 



Wave-length. 

 (Rowland's 

 scale.) 



Intensity 

 in flame 

 (L). 

 Max. = 10. 



Intensity 



in arc 

 (K & R). 

 Max. = 10. 



Length in 

 arc (L). 

 Max. = 10. 



Intensity 

 in spark 

 (T). 

 Max. = 10. 



Intensity in 

 hot spark 



(L). 

 Max. = 10. 



3720 



8 



















3724 



8 



...,„ 



„ 











3734 



6 



















3829 '51 



4 



10 



10 



10 (C) 



10 



3832 -46 



6 



10 



10 



10 (C) 



10 



3838 '44 



8 



10 



9 



10 (0) 



10 



3850 '2 





4 (L) 







4 



2 



3856 '2 







5 (L) 







4 (H k A) 



4 



3892 '7 





3 (L) 





4 



4 



3896 '7 





3 (L) 







4 (H & A) 



4 



3987 '08 







2 











2 



4058 -45 







2 







2 (L & D) 



1 



4167 *81 







1 









4 



4352 '18 







8 



10 







5 



4395 















3 



4481 *3 















8 



10 



4571 -33 



7 



4 



1 



2 (L & D) 



2 



4587-4 









4 



2 



4703 -33 





8 



6 



8 



4 



4730 -42 





1 







3 



5006 -5 



10 











f 5167 -55 





8 



3 



8 



7 



b \ 5172 -87 



10 



10 



5 



9 



9 



L 5183 -84 



10 



10 



5 



10 



10 



5210 



10 











K & R = Kayser and Runge. 

 L = Lockyer. 

 T = Thalen. 

 C = Comu. 



H & A = Hartley and Adeney. 

 L & D = Liveing and Dewar. 



is bright enough to be studied with sufficient precision for our 

 present purpose, while 7 Cygni, a, Cygni, rj Leonis, Rigel, Tauri, and 

 Bellatrix are taken as types of stars at temperatures which increase 

 in the order named as determined by a comparison of the extension 

 of the spectra into the ultra-violet in accordance with what has 

 already been stated. 



The lines photographed in the spectrum of each star shown on the 

 map (Map I) are drawn with lengths proportional to their estimated 

 intensities, the strongest line in each being represented by a line 

 equal to the full width of the strip devoted to each spectrum. 



The results shown diagrammatically in Map I are further illus- 

 trated by actual photographs of stellar spectra in Plate 2. 



