[ 339 J 
XII. 
BANDED FLAME-SPECTRA OF METALS. By W. N. HARTLEY, F.R.S., Honorary 
Fellow of King’s College, London; Royal College of Science, Dublin; and HUGH 
RAMAGEH, B.A., A.R.C.8c.L., St. John’s College, Cambridge. 
(Prates XXIX.-XXXIII..) 
[Read May 22np, 1901. ] 
In ‘‘Flame-Spectra at High Temperatures,”* it was proved by one of the authors 
that metals easily volatilised exhibit banded spectra. 
Characteristic flame spectra of elements were described as follows + :— 
‘“‘ Band Spectra—Antimony, bismuth, gold, tin, sulphur, selenium.” 
‘““ Band Spectra with Lines—Copper, iron, manganese, tellurium, lead, and 
silver.” 
In addition to these the ‘‘ Spectra peculiar to Compounds,” such as calcium 
oxide, calcium fluoride, and magnesium oxide, were described as containing lines 
and bands.t A summary of similar work previously published, giving a few 
instances of bands in metallic spectra, was included in the paper and appendix. 
It is stated on pp. 166—7 that tne band-spectra of silver and gold are really due 
to the metals, ‘‘since no oxides of these metals can exist at the temperature of the 
flame employed.’ Reasons are also given for attributing the bands in the flame- 
spectra of manganese and of its compounds to the metalitself. The relation of 
line-spectra to band-spectra is also discussed on p. 167. ‘The two other papers, 
entitled Parts II. and ILI. of ‘‘Flame-Spectra at High Temperatures,” were 
published also in the same volume. 
The continued investigation of this subject has been jointly prosecuted for the 
last six years by the authors of this communication. Photographs of the spectra 
) 
have been taken with a four-prism spectrograph.§ This instrument gives wider 
dispersion and better definition than the one-prism instrument used in the earlier 
part of the investigation. By this means, and by small but important improve- 
ments in the method of working, finer detail has been obtained, new band-spectra 
have been discovered, and some of the bands which had been previously photo- 
graphed have now been resolved so as to clearly show their component lines. 
The spectrum of silver, which has already been completely described in the 
first paper above-mentioned, is remarkable for the character of the banded spectrum 
* Phil, Trans., vol. 185 (A.), 1894, pp. 161-212. 
+ See p. 166. t See p. 168. § Phil. Trans., vol. 185 (A.), 1894, p. 1047. 
TRANS. ROY. DUB. 8OC., N.S. VOL. VIJ., PART XII. 3A 
