350 HartLey AnD Ramace—Banded Flame-Spectra of Metals. 
Band Spectra: Arsenic, vanadium, yttrium, cerium, praseodymium, neodymium. 
The compounds of the last four elements under examination in all probability 
yield oxides, and the spectra are those of the oxides. 
Band and Line Spectra: Nickel, cobalt, rhodium, and iridium.—Most probably 
the spectra are those of the metals. 
It must be understood that the flame-spectra in these cases give lines in 
_ addition to bands, or bands in addition to line-spectra, sometimes as if they 
were components of different spectra, and in some cases as if the lines arose out 
of the edges of the bands by some change in the conditions of the flame. 
Germanium.—Very faint indications of bands have been obtained also in the 
flame-spectrum of germanium. 
There can now be no doubt that band or channelled spectra are given alike by 
metals as well as by metalloids such as tellurium and arsenic, or non-metallic 
elements such as sulphur and phosphorus. It is equally true that these bands are 
entirely due to the metals in many cases, though there are instances of bands or 
broad lines being undoubtedly rendered by compounds, as for example, under 
certain conditions, by the haloid salts of the alkaline-earth metals, also by haloid 
salts of gold and of copper. 
CoNCLUSIONS. 
(1). Metals of very different characters belonging to different groups in the 
periodic system of classification yield banded spectra or spectra composed of both 
bands and distinct lines. As examples, we have magnesium, zinc, and cadmium ; 
copper, silver, and gold; aluminium, indium, and thallium; palladium and iridium ; 
bismuth, tin, and lead. 
(2). Metals which are combustible and which evolve a large amount of heat upon 
combustion, forming oxides which are but slightly volatile, yield banded spectra ; 
so also do those metals the oxides of which are easily volatilised, and furthermore, 
those metals that do not form oxides at the temperature of the flame. 
(3). Certain groups of elements yield banded spectra which are degraded 
towards the less refrangible rays, as, for instance, the metals copper, silver, and 
gold ; aluminium and indium; beryllium and lanthanum ; others exhibit spectra the 
bands of which are degraded on the more refrangible side, as magnesium, zinc, and 
cadmium. 
(4). Many lines, independent of those bands which are composed of fine lines, 
are present in the flame-spectra of palladium and iridium. Both of these metals 
are difficult to volatilise in the oxyhydrogen flame; hence only small quantities of 
the vapour are present in the flame. The same feature belongs to the spectra of 
some of the metals which are easily volatilised, when only small quantities are 
present. 
