330 
PROFESSOR W. N. HARTLEY OX SPECTRUM PHOTOGRAPHY 
Tabular Description of the Spectra characteristic of Solutions containing Magnesium. 
Scale numbers. 
Wave-lengths 
of the principal 
lines visible. 
Parts of magnesium per 100,000 of solution. 
1,000 
100 
30 
20 
10 
3 
o 
1 
Hundredths of an inch. 
17-46 
4480 
* 
45= 
59-30 
'3837-9 
45= 
45= 
59-83 
3832-1 
* 
45= 
45= 
45= 
60-07 
3829-2 
4£ 
45= 
142-3 
'3096-2 
* 
45= 
142-85 
3091-9 
* 
45= 
143-18 
3089-9 
* 
45= 
168-7 
J 
2935-9 
* 
* 
45= 
45= 
45= 
* 
* 
170-18 
1 
[2928-2 
* 
45= 
45= 
45= 
45= 
* 
45= 
184-63 
2851-2 
* 
4s= 
45= 
45= 
45= 
45= 
* 
* 
194-55 
f 2801-6 
4S= 
45= 
* 
45= 
45= 
* 
45= 
* 
195-39 
J 
2796-9 
* 
45= 
45= 
45= 
45= 
* 
* 
45= 
195-95 
2794-1 
4S= 
* 
45= 
45= 
45= 
* 
* 
45= 
196-92 
2789-6 
* 
45= 
45= 
* 
45= 
45= 
# 
* 
198-64 
f278P8 
4t= 
45= 
* 
198-96 
2780-2 
199-3 
«< 
2778-7 
# 
45= 
* 
45= 
* 
199-61 
2776-9 
199-97 
P2775-5 
4£= 
45= 
The following tables, together with the maps of the lines, are considered to be 
sufficiently descriptive of the different spectra. The wave-lengths of the lines 
characteristic of each solution are given in separate columns. 
The Zinc Spectrum. 
Scale numbers. 
Wave lengths. 
1 per cent. 
0U per cent. 
0’01 per cent. 
Hundredths of an inch. 
108-49 
3344-4 
3344-4 
3344-4 
113-75 
3301-7 
3301-7 
3301-7 
116-30 
3281-7 
3281-7 
3281-7 
145-69 
3075-6 
3075-6 
194-98 
2800-1 
2800-1 P 
252-31 
2557-3 
2557-3 
267-95 
2501-5 
2501-5 
The most persistent lines of zinc are probably those of high refrangibility which do 
not ordinarily appear when gelatine emulsion plates of the kind most generally used 
are employed. 
* Lines which are visible. A line may be shortened or weakened, but an asterisk opposite to its 
wave-length in this table denotes that although it may be changed it is still visible. Only the first, 
third, and fifth lines of the quintuple group have been mapped. 
i-V 
