ON THE ULTRA-VIOLET SPARK SPECTRA. 283 
Scale numbers 
The Lead Spectrum. 
Wave-lengths 
1 per cent. 0-1 per cent. 0-01 per cent. 
Hundredths of an inch 
42°93 4057°5 4057°5 
67°61 3738°9 3738'9 
72:69 3682°9 3682:9* 
76°8 3639-2 3639°2 
83°31 3572°6 3572°6 3572°6 
170°45 2872°2 2872:2+ 
188°37 2832°2 2832-2 
190°30 282271 
225-41 2662°5 2662-5 
237-48 2613-4 2613-4 
247-08 2576-4 
373°43 2204:°3 
The Telluriwm Spectrum. 
Wave-lengths 
Scale numbers : 
Scale numbers 
1 per cent. 01 per cent. 0-01 per cent. 
‘Hundredths of an inch 
103-9 3382-4 33824 
116-43 3280:0 3280°0 
117°35 3273-4 3273°4 
120°77 3246 8 3246°8 
176°24 2894°3 
181:25 2867°7 
183°4 2857:0 
3441 2386°3 2386°3t 
304-92 2383°8 2383°8t 
355°18 2248-0 
355°36 2247°3§ 
357-18 2243°3 
The Arsenic Spectrum. 
Wave-lengths | 
1 per cent. 0-1 per cent. 0-01 per cent. 
‘Hundredths of an inch 
18304 2859-7 
199-22 2779°5 2779'5 
3166 2350°1 
339°14 2288°9 
0 SE ee a ee ee ee ee eee 2 eee ees eee | 
This is an exceedingly poor spectrum. 
* Barely visible. t+ Very faint. 
{ These lines appear very distinctly and are continuous in a 1 per cent. solution. 
§ The two last lines are faint, 2243°3 exceedingly so. 
