

Neio Table of Standard Wave-lengths, 



69 





In Arc. 



In Sun. 



Kind 

 of 



Weight. 



Wave- 



Wave- 



Elements. 







Stand- 





length 



length 

















Inten- 



Appear- 



Inten- 



Appear- 



ard. 



In 



In 



in Arc. 



in Sun. 





sity. 



ance. 



sity. 



ance. 





Arc. 



Sun. 



7 







Na 







6 





0" 





5688-434 



Fe 



4 





5 





0" 





8 





5701-769 



Si 







5 





0" 









4 





5708-620 



Fe 







8} 



a 





6 





5709-616 



m , 



5 





O 





8 





5709760 



Mg* ... 







6 



... 



M© 



4 





5711-374 



5711-318 



m \ 



Fe-Ti j 



1) 





5 





0" 





10 





5715-309 



Fe 







5 



... 



0" 





10 





5731-973 



Fe 







3 











10 





5742-066 



Fe 







4 





0" 





10 





5752-257 



Fe 







5 





0" 





10 





5753-342 



?} - 



Fet 







5 





0" 





9 





5754-884 







7 





0! 





8 





5763-215 



Si 







5 





0" 





6 





5772-360 



Fe 







5 







9 





5775-304 



Cu?Co? . 







7 



d? 



0" 





9 





5782-346 



Cr 



6 



... 



4 





0" 





9 





5784-081 



Cr 



7 





5 





O" 





13 





5788-136 



Orl 



Fej - 

 ? 



10 





7 



d? 



0" 





16 





5791-207 







4 





O" 





10 





5798-087 



Fe 







5 





0" 





9 





5798-400 



Ni ...... 



7 





5 





0" 



... 



8 





5805-448 



Fe 







5 





0" 





7 





5806-954 



Fe 



... 





5 





O" 





14 





5809-437 



Fet 







6 





©1 





14 





5816-594 



Ni 



3 





3 





0' 



... 



6 





5831-832 



Ba 



10 





5 





O" 





14 





5853-903 



Ca§ 



10 





7 





0' 





14 





5857-672 



Fe 







6 





0" 





15 





5859-810 



Fe 







6 





0" 





16 





5862-580 



D 3 He|| ... 



















5875-982 



Fe n 

 A(wv) j 







SI 



d 



Oi 





11 





5884-048 



A(wt) . . . 





.. 



3 





01 





8 





5889-854 



D 2 Na 







15 





0' 





20 





5890-182 



m** 



3 



d? 



4 





© 





14 





5893-098 



* This Mg line is shaded on one side, especially when there is much Mg in 

 the arc and therefore should not be used for a metallic standard. (R.) 



t There is a fine line near to violet side. 



J There is a line close to violet side. § There is a "Si line near to red. 



|| This value of the wave-length of D 3 is the result of three series of measure- 

 ments made with a grating having 20,000 lines to the inch, and is accurate to 

 perhaps 02. 



Observations were made in the first spectrum on botb sides of the Sun. The 

 line does not occur as a dark line in the solar spectrum ; but is sometimes, if 

 not always, present as a very weak bright line. This is shown by a study of 

 the best photographs of this region of the solar spectrum. (J.) 



Tf A water-vapour line is toward the red about 0-080 from the Fe line and 

 ordinarily forms a double with it. 



** An exceedingly close equal double when there is very good definition. 

 There is also a solar line near to the violet side, and a water-vapour line near 

 to the red. (J.) 



