232 Scientific Proceedings, Royal Dublin Society. 
STRONTIUM. 
Strontium chloride was the salt used. The most persistent 
lines were situated in the visible part of the spectrum, the residuary 
lines AA 4607-5, 4305°6, 4215°7, and 4077°9 being faintly seen 
with a dilution of ;y4gp0- AS in the case of barium, we were 
unable to test the difference between the spark-spectrum of the 
metal and a strong solution. 
Plate X VIII.—Spectra 6 and 7 show the spectra with 10 per 
cent. and | per cent. of the element respectively ; and those lines 
that persist with greater dilutions are dotted. 
Quantitative Spectrum of Strontium Chloride. 
Mae Wave- Intensity Monee Wave- Intensity 
bee t, length: eee me Hemguia. Pes 
zdo inch. yao inch. 
248-80 5535-0 Bauer 289-70 4607°5 10” 
249-40 5522°0 BG 307-80 [No. 11, | Gold.] 
249-90 5504-5 Moats 308-50 4305-6 30) ia 
no 5486-4 6) : 314-80 4215-7 100 @ 
5481°1 10) 318-80 4162-0 200 
251:85 5451-1 5 oo 325-30 4077-9 | 100. 
259-10 52071 3G 326-35 [No. 12, | Gold.] 
271°60 4962-4 Selmi) 329-20 4032°5 [4] o 
275-75 4876-3 6 «o || 340-80 [No. 13, | Gold.] 
277-80 4832-2 8 eG | eeees 3475-0 ds 
278-80 4812:0 6 « | 388-00 3464-6 100 
279:80 [No. 9, | Gold.] | 399-00 [No. 15, | Silver.] 
282-35 4742°1 6 « || 399-50 3380°9 Ae oe | 
283°40 4729-4 Ge || 403-50 3351°3 eee 
‘CALCIUM. 
Calcium chloride was the salt used; and, as in the case of barium 
and strontium, the most persistent lines were situated in the visible 
part of the spectrum, the residuary lines being \\ 4226-9, 3968°6, 
and 3933°8. On taking the spark-spectrum of the metal, it was 
found to contain magnesium, manganese, and silicon ; but in addi- 
