Arc Spectra of some Metals. 

 Table I. (continued). 



501 



Wave-lengths of Lines which 

 are relatively 



Remarks. 



Intensified. 



Weakened. 



Unaffected. 



2936-61 

 2928-74 



2852-22 

 2768-57 



2942 21 

 2938-67 

 2936-99 



2915-57 



[2852-22] 

 2848-53 

 2846-91 



2802-80 

 2798-07 

 2795-63 



2790-88 

 2783-08 

 2781-52 

 2779-94 

 2778-38 

 2776-80 



> Second Subordinate Series. 



Strong spark-line. 

 Strong spark-line. 



Strong spark-line. Width of re- 

 versed portion increased at least 

 10 times. Line as a whole nearly 

 extinguished. 



"\ First Subordinate Series. From 

 analogy, the first line of this trip- 



}■ let, here covered by the heavy 

 spark-line, ought to be unaffected 



J by hydrogen. 



Intensity unaffected : reversal greatly 

 increased. 



Reversal greatly increased. A second 

 reversal, not occurring in the 

 ordinary arc, appears in the shade 

 of this line, at a distance of - 7 

 tenth-metres toward the violet. 



Width and reversal increased. 



The line at 2765*47 and the five triplets of still shorter 

 wave-length which complete Kayser and Runge's list of 

 magnesium lines, are so entirely blotted out by the hydrogen 

 atmosphere that no comparison is possible even on plates of 

 four hours' exposure. And this is true even while many 

 sharp lines, impurities, of still shorter wave-length appear on 

 the negative. 



