218 
PROFESSORS G. D. LIYEING AND J. DEWAR ON 
Calcium lines. 
Approximate 
wave-lengths. 
39677 
3972-3 
3956-0 
3947-9 
3933-0 
3736-4 
3705-5 
36440 
3631-0 
3623-5 
3486-5 
3474-5 
3468-0 
3359-5 
3347-5 
3342-0 
Remarks. 
H. 
Sharp triplet. 
K. 
Mapped by Cornu. 
Ditto. 
Very strong. 
Readily reversed. 
Sharp triplet. 
Very strong. 
Approximate 
wave-lengths. 
Remarks. 
3285-0 
3273-5 
3268-5 
3224-5 
3213-0 
3208-0 
3181-0 
3179-0 
3168-5 
3158-8 
3151-0 
3141-0 
3136-0 
3117-5 
3108-0 
2398-0 
Sharp triplet. 
Diffuse triplet. 
Mapped by Cornu. 
R. ditto. 
Ditto, not seen by us. 
Mapped by Cornu. 
| Weak, very diffuse. 
Zinc. 
Zinc is another metal which gives a well-marked apparently harmonic series of 
triplets, but the different lines of each group are further separated than in the calcium 
or magnesium triplets. The middle line of the first triplets confounds with the sodium 
pair wave-length 3301, but by reason of the diffuse character of the zinc line we have 
not been able to decide whether the coincidence is more than approximate. 
Zinc lines. 
Approximate 
wave-lengths. 
Remarks. 
Approximate 
wave-lengths. 
3342-0 
2608-5 
3301-0 
2582-0 
32810 
. 
1 
2569-7 
3070-0 
1 
2516-0 
3035-0 
2491-5 
3017-0 
2480-0 
2800-0 
] 
2464"5 
2770-0 
>■ Diffuse. 
2440-0 
2756-0 
2430-0 
2713-3 
1 
2684-0 
> 
2670-5 
J 
Remarks. 
Diffuse. 
Very diffuse. 
Mercury. 
As might be expected from its volatility, it is difficult to obtain lines of mercury in 
the arc ; but one line gives a reversed image of itself at wave-length 2536 'S. This 
line is very bright in the flame of cyanogen, containing vapour of mercury. 
