E. E. Lawton — Bands in the Spectrum of Nitrogen. 103 



obtained. At A.4059 and \8998 there are two bands which 

 present beautifully: the phenomena of triplets. Just above 

 there is a group of six bands which overlap each other in such 

 a way as to entirely obliterate the triplets. 



The wave-lengths of the bands beginning at A, 4059 and 

 X3998 have been measured and the results are given below. 

 The stronger dispersion has made it possible to measure nearly 

 a hundred more lines in these two bands than did the early 

 observers. The measurements have been made with the aid. 

 of a micrometer-microscope especially arranged for the pur- 

 pose, and in each case measurements have been made by set- 

 ting on the center of intensity of the lines. Each result given 

 in the table is the mean of at least eight measurements. 

 Taking 10 _7mm as the unit, the precision of measurement 

 should be at least equal to 0*01 of that unit, except in the case 

 of the extreme triplets, which being rather faint, the setting 

 is more uncertain. The measurements of the wave-lengths 

 follow. 



Wave-lengths of the 



4059 



4058 



4057 



4056 



1055 



4054 



4053 



f the I 



tan 



ds 



beginning at J f .05 l 



1-458 



and 8998-419 



•458 







4053-790 



4046 



•227 



•207 







•347 



4045 



•781 



•015 







•107 





•446 



•895 







4052-89S 





350 



•694 







•730 





016 



•511 







•370f 



4044 



727 



•403 







•27lf 





•336 



•084 







4051-987 



4043 



873 



•883 







•657 





185 



•576 







•291 



4042 



927. 



•351 







•059 





744 



•119 







4050-863 





399 



•979 







■482f 





208 



•628 







■268f 



4041 



853 



•504 







•179 





571 



•266 







4049-781 





200J 



■030 







•167 



4040 



815 



•831 







4048-943 





509 



•524 







•442 



4039 



902 



•359 







4047-959 





L89 



•077 





- 



•597 



403 8 



731 



•639 







•164 



4037 



780 



408* 







4046-964 





447 



•245 







•679 



4036 



981 



■896 







•494 



•281 



*Very faint. 



\ A heavy double. 



% Faint and difficult to measure. 





