Mr Talbot's Experiments on Coloured Flames. 81 



faintness of the lamp prevented my comparing it directly with 

 the sun. This red ray appears to possess a definite refrangi- 

 bility, and to be characteristic of the salts of potash, as the 

 yellow ray is of the salts of soda, although, from its feeble 

 illuminating power, it is only to be detected with a prism. 

 If this should be admitted, I would further suggest, that when- 

 ever the prism shows a homogeneous ray of any colour to 

 exist in a flame, this ray indicates the formation or the pre- 

 sence of a definite chemical compound. An excellent prism 

 is, however, requisite to determine the perfect homogeneity of 

 a ray. 



5. Phosphorus inflamed with nitre gives a very brilliant 

 spectrum, in which no colour appears to be predominant or 

 deficient. It therefore resembles the spectra of ignited lime, 

 platina, and other solid bodies, and differs totally from the 

 solar spectrum in which there are now known to be innume- 

 rable interruptions of light. And it is worthy of remark, that 

 no light has been hitherto discovered at all resembling that of 

 the sun, (when analyzed with a prism) except the light of the 

 other celestial bodies. 



6. The red fire of the theatres examined in the same way, 

 gave a most beautiful spectrum with many light lines or maxi- 

 ma of light. In the red, these lines were numerous and crowd- 

 ed, with dark spaces between, besides an exterior ray greatly 

 separated from the rest, and, probably, the effect of the nitre 

 in the composition. In the orange was one bright line, one in 

 the yellow, three in the green, a very bright one in the blue, 

 and several that were fainter. The bright line in the yellow is 

 caused, without doubt, by the combustion of the sulphur, and 

 the others may be attributed to the antimony, strontia, &c. 

 which enter into this composition. For instance, the orange 

 ray may be the effect of the strontia, since Mr Herschel found 

 in the flame of muriate of strontia a ray of that colour. * If 

 this opinion should be correct and applicable to the other de- 

 finite rays, a glance at the prismatic spectrum of a flame may 

 show it to contain substances, which it would otherwise re- 

 quire a laborious chemical analysis to detect. 



London, March 1826. 



" Edinburgh Transaction*, vol. ix. p. 456. 

 vol. v. no. i. jury 1826. r 



