% 
234 Scientific Proceedings, Royal Dublin Society. 
the ultra-violet part of the spectrum, the residuary lines being 
AA 2852°2, 2798:2, and 2790:9, 
The metal gives one or two strong lines that are not seen, or 
only very faintly seen, with strong solutions. Those lines are 
marked r. 
The quantitative spectrum of magnesium was previously inves- 
tigated by Professor W. N. Hartley, and his results are in accord- 
ance with the present observations ; but as explained in a previous 
paper, Professor Hartley’s method of observation gave a greater 
quantity of vapour, and an apparently greater persistency of the 
lines ; but the relative persistencies are substantially the same, and 
the residuary lines are identical. 
Plate XIX.—Spectra 1, 2, and 3 show the spectra of the metal, 
a 10 per cent. solution, and a 1 per cent. solution. 
Quantitative Spectrum of Magnesium Chloride. 
D . | 
fer | gt [cat |r | 
ai at | "| Persistency. eae eng”: | Persistency. 
| { 
253°13 5528-7 6 o 444-45 [No. 17, | Gold.] 
265:90 5183-8 10 @ 449-00 3097-1 [8] 9 
266-80 5167-6 8 ¢ 449-85 3093-1 [s] ¢ 
283-85 [No. 9, | Gold.] 462°00 | [No. 18, | Gold.] 
288-50 4703°3 [8] 7 480-85 2937-0 10 
300-85 [No. 10, | Gold.] 482-50 2928-7 10 
301-30 4481-3 10 o 485°40 2915°5 10 
309-45 4352°2 [8] 7 499-80 2852°2 10 @ 
345-00 [No. 13, | Gold.] 506-10 [No. 20, | Gold.] 
350-60 3838-4 10 o 512-70 2798-2 3 6 
se f 3832°5 10) yc; 514°55 2790°9 10 @ 
| 3829°5 io 51650 | ( 27831 4 
403°40 [No. 15, | Silver. ] | 2781°5 4 p 
409-95 3336°8 Sub te | to } 9779°9 6 x 
410:60 3332-3 Sing oo 2778-4 AT acs 
411-05 3330-1 6 G | 518-20 | 2776:8 Ar Oe 
