WAVE-LENGTHS OF CERTAIN LINES. 185 



The numerical values of the wave-lengths of most of the conspicuous spark- 

 lines are given in the subjoined table. The numbers in the first, fourth, and 

 seventh columns are arbitrary and correspond to the like numbers of plate 

 1 (a) , thus making the identification of the wave-lengths with the spark-lines 

 easy and unambiguous. The data in the second, fifth, and eighth columns 

 are the wave-lengths expressed in Angstrom units. The subscripts 2, which 

 affect the numbers in the last column, indicate that the associated wave- 

 lengths appertain to spectral lines of the second order. 



WAVE-LENGTHS OF REFERENCE LINES. 



1 2024.2 Zn 35 3436 .9 Air 62 4576 .2 Cd 9 2 



f 2060. 8 Zn <3466.3Cd 63 4601 .6 Air 



I 2062 .8 Zn \ 3467 .8 Cd 64 4607 .3 Air 



3 2099.0 Zn 37 535.0 Cd 65 4614 .0 Air 



4 2138. 3 Zn (3610. 7 Cd 66 4621 .6 Air 



5 2144.5 Cd (3613.0 Cd 67 4626.0 Cd 11 2 



6 2194.7 Cd 39 3535.0 68 4630 .7 Air 



7 2239. 9 Cd 40 3712 .2 Air (4641 .9 Air 



8 2265.1 Cd 41 3726 .6 Air (4643 .4 Air 



9 2288.1 Cd 42 3749.8 Air 70 4649.2 Air 



10 2306 .7 Cd ( 3839 .3 Air 71 4680 .4 Zn 



11 2313.0 Cd \3841.7Air 72 4722 .3 Zn 



12 2321. 2 Cd 44 3881 .9 Air 73 4800. 1 Cd 



13 2329 .3 Cd 45 3919 .2 Air 74 4810 .7 Zn 



14 2502.1 Zn (3954 .8 Air 75 4912 .3 Zn 



4n "\ 



15 2558 .0 Zn (3956 .2 Air 76 4924 .8 Zn 



16 2573.1 Cd 47 3972 .5 Air (5002 .7 Air 

 (2710.1 Air 48 3995.1 Air 77 (5005 .7 Air 

 (2712 .6 Zn 49 4041 .4 Air 78 5045 .7 Air 



18 2748. 7 Cd (4070 .0 Air 79 5086 .1 Cd 



19 2770.9 Zn 50 -^ 4072 .4 Air gO 5116.0Znl5 2 



20 2801.0 Zu U076.1 Air 81 5146.2 Cd 16 2 



21 2837 .0 Cd 51 4119 .4 Air 82 5338 .6 Cd 



22 2880.9 Cd (4132 .8 Air 83 5354 .4 Cd 3 



23 2980.8 Cd (4133 .8 Air 84 5379 .3 Cd 



24 3007.0 Air 53 4145 .9 Air 85 5497.4CdlS 2 



25 3035 .9 Zn f 4151 .9 Air 86 5509 .0 Zn 3 

 (3072.2 Zn \4153.6 Air 87 5541.8 Zn 19 2 

 "(3076.0 Zn / 4228 .5 Air 88 5602.0 Zn 20 2 



27 3133. 3 Cd 55 -s 4236 .7 Air 89 5761 .8 Cd 22 2 



28 3250.5 Cd (4241 .9 Air 90 5961 .6 Cd 23 3 



29 3261. 2 Cd f 4316 .2 Air 91 6014.0 Air 24 2 



30 3282 .4 Zn t 4318 .7 Air 92 6035 .0 Zn 2 



31 3302 .7 Zn 57 4349 .5 Air 93 6071 .8 Zn 25 3 

 (3329.3 Air 58 4367.9 Air 94 6144.4 Zn 26 2 



32 (3331 .5 Air 59 4415.1 Air 95 6152.0Zn26 2 

 (3345.1 Zn f 4447.1 Air 96 6160 .4 Cd ~- 2 



33 (3345.5 Zn (4447 .2 Air 97 6266.6Cd27 2 



34 3403.7 Cd 61 4530.1 Air 



