THE STRUCTURE OF THE SERIES OF LINE- AND BAND-SPECTRA. 585. 
Single Line Series. Double Line Series. 
6877°41 
6879°72 
6882°26 
6885-09 6885°04 
688818 6888:08 
6891°46 6891°36 
689508 689492 
6898°70 
Here a remarkable phenomenon will be noticed, viz. that the positions of the 
s of the double lines in the second series agree very nearly with those of the 
ines of the first series. This is not accidental, because the other groups show 
same feature. We have, for instance, in the A-group: (LxsreEr, /.c., pp. 88 and 92) 
Single Line Series. | Double Line Series. 
7615°87 
7619°04 
7622°49 7622°40 
7626°14 7626°04 
7630°04 7629°90 
: 7633°98 
Single Line Series. | Double Line Series. 
6284°38 
6286°49 
6288°84 6288°77 
(6291°48) 6291°38 
6294:26 
Ve notice, then, that at the point where the second series begins the line of the first 
alls between the components of the former, and if its intensity is still sufficiently 
and the doubles close, the effect of superposition will be that the resulting line 
rs as a broadened single line. Hence the lines of the first series, which near the 
are thin and sharply defined, will gradually widen out. But since the intensity 
[ the first series declines rapidly, their vitiating effect will lessen, the further we 
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