22 THE CHEMISTRY OF THE SUN. [CHAP. n. 



and stars, and on applying this method discovered that the 

 spectra of the planets are essentially the same as that of the 

 sun, whilst the stars have independent spectra. Coming to 

 artificial flames he found that their spectra are characterised by 

 the presence of bright lines, and that one, at least, of these 

 lines is exactly matched in width, duplexity, and position by a 

 similar double line in the solar spectrum. Finally we have his 

 observation that the spectral phenomena presented by a candle 

 flame and an electric spark are localised in special regions. 



We have not even yet exhausted the contributions of this 

 remarkable man to -our subject. He brought the study of the 

 diffraction of light, as well as its refraction, to a point at which 

 it could be utilised for the furtherance of solar research. Dis- 

 carding the old methods of observation, or rather improving them, 

 he replaced the edge and aperture employed up to that time by 

 a fine system of wires, the intervals between which provided 

 him with parallel and equi-distant apertures in great number. 1 



Observing diffraction phenomena in this manner he was 

 delighted to see what had formerly been observed as coloured 

 fringes merely, developed into beautiful spectra. 



" On apergoit dans les spectres produits par le fils du reseau les 

 meme raies, les meme bandes, que j'ai decouverte dans les spectres 

 produits par la luniiere solaire au inoyen de bons prismes." 



In the parallel wires of Fraunhofer we have the forerunner 

 of the " grating," or " rtseau" the utilisation of which we shall 

 see in the sequel. 



1 For Frauuhofer's paper, "Neue Modification des Lichtes," see Denkschriften 

 d'er'K. Akademie zu Milnchen, 1821-1822; Classe der Mathematik und Natur- 

 wissenschaften, pp. 1-76 ; also Gilbert's Annalen, 1823, and Schumacher's Tracts, 

 3823, p. 46. 



