THE LINES OF THE SOLAE SPECTEHM. 
159 
31 and September 1, 1859, it was seen from Shoreham and Worthing, at the distance of 
twenty-five and twenty-seven miles respectively, and across the sea, like a star of the 
second magnitude, but of an orange colour. On examining it by the prism and tele- 
scope, it was resolved into a thread of light of a pale yellow colour, shading off* into red 
at one end and into green at the other, while absorbent glasses showed that the spec- 
trum did not extend either way beyond C and F. No lines were detected. The result 
therefore is unfavourable to the above supposition; for though twenty-seven miles of 
atmosphere, even at its densest, could not be expected to produce what are described 
above as “ atmospheric lines,” D and h might reasonably have been looked for ; yet on 
account of the faintness of the light, and the difiiculty of distinguishing with certainty a 
minute break in a flickering luminous thread, no grpat reliance should be placed on this 
negative result. The stars promise the best means of solution, since their light traverses 
precisely the same terrestrial atmosphere as that of the sun does. Fraunhofer saw, as 
was antecedently probable, some new lines of absorption in the spectra of certain fixed 
stars, while he recognized the line D in Pollux and Procyon, and the lines D and h in 
Capella and Betalgeus. Yet he did not observe these familiar lines in the spectra 
of Sirius and Castor ; but it may be fairly open to doubt whether this did not arise from 
the extreme difficulties attending the observation. The experiments of the present 
authors in this direction, though they have had the use of powerful telescopes, have not 
led to any definite conclusions as to these lines, but they have both noted other remarkable 
phenomena of absorption, especially on examining the spectra of the coloured stars*. 
The origin of the fixed lines of the solar spectrum must therefore still be considered 
an undecided question f. 
Luminous Bands in Artificial Lights. 
WTiile the spectra of some artificial fights exhibit all the coloured rays gradually 
shading one into the other, those of some other fights consist of a series of luminous 
bands separated by dark spaces ; and one of the most remarkable facts is this, that these 
luminous bands sometimes coincide with the dark fines of the solar spectrum. Thus the 
intense yellow fight of the soda-flame is well known to have the same refrangibility as 
D ; and this ray is prominent also, according to W. A. Miller, in the flames of lime, 
strontia, baryta, zinc, iron, and platinum, and, according to Angstrom, in the electric 
flames of every metal examined by him. But the most remarkable case occurs when 
carbon or sulphur is burnt in nitre. The brilliant light, when analysed by a prism, 
exhibits a spectrum about as long as that of the sun at noon day, but marked by 
bright fines, among which three are particularly prominent, respectively violet, yellow, 
and red in colour. The violet ray is not quite so refrangible as the solar H, but the 
yellow is coincident with D, and the red with A, while between the red and yellow 
* For Sir D. Beewstee’s observations see his ‘ Optics,’ Ed. 1853, p. 94. 
t AVTierever they originate it is possible that they may be phenomena of interference, as Sir David Beew- 
STEE has observed analogous lines and bands in portions of decomposed glass consisting of numerous films. 
