CHAPTER X. 



THE LIGHT OF THE STABS. 



" THAT a science of stellar chemistry should not 

 only have become possible, but should already 

 have made material advances, is assuredly one 

 of the most amazing features in the swift pro- 

 gress of knowledge our age has witnessed/' So 

 writes Miss Agnes Mary Clerke, the historian 

 of modern astronomy. As long ago as 1823 

 Fraunhofer observed the spectra of the brighter 

 stars, and gathered the first hint of the group- 

 ing of the stars into three classes. Then, after 

 Fraunhofer's death, the subject lay in abeyance 

 for thirty-seven years. At length, in 1860, on 

 Kirchhoffs explanation of the Fraunhofer lines, 

 the study of stellar spectra was inaugurated at 

 Florence by Donati, who carefully fixed the posi- 

 tions of the more important lines. His instru- 

 mental means, however, were very limited, and 

 his observations were not successful. In 1862 

 Rutherford, in New York, commenced the study 



