CELESTIAL DISSOCIATION. 197 



The lines constituting the discontinuous spectrum of an 

 element, as normally produced, are bright lines; that is, they 

 have definite colours. In the beginning of the last century 

 Fraunhofer discovered that the continuous band of color 

 constituting the spectrum of sunlight was broken by a 

 great number of lines as in the case of a discontinuous 

 spectrum, but that these lines were dark instead of light. 

 The explanation of this lay in the fact that the great mass 

 of the highly heated interior of the sun gives rise to light 

 of every conceivable wave-length constituting the continuous 

 spectrum, and that the incandescent gases surrounding 

 this heated interior have the selective power of absorbing 

 the very light-waves they themselves emit and thus give 

 rise to dark lines which, if it were not for the heated in- 

 terior of the sun, would be bright. These dark line spectra 

 are called Fraunhofer's lines. Fig. 49. They constitute the 

 spectra of all the incandescent gaseous substances existing 

 in the atmosphere of the sun. Lines of the spectrum of 

 any one substance in this atmosphere occupy the same 

 relative positibns as they do upon earth and hence the sub- 

 stance may be recognized with as much certainty as though 

 it existed in the laboratory instead of 93,000,000 miles away. 



With these definitions we are now in a positic n to take 

 up the business of our subject the question as to whether 

 or not the elements exist in decomposed simpler forms in 

 the sun and stars. The work done on this subject com- 

 prises forty years cf the life of Sir Norman Lockyer. 

 Other men have made their contributions, both directly 

 and indirectly, but Lockyer has been the foremost champion 

 of the idea and to him alone belongs the chaplet of the 

 victor. One of the first tasks put before Lockyer in the 

 pioneering stage of his work was the removal from the 

 mind of science of a serious misconception. Men were 



