386 THE BEAUTIES OF NATURE chap. 



might, therefore, be used as a convenient 

 mode of analysis. In fact, by this process 

 several new substances have actually been 

 discovered. These bright lines were found 

 on comparison to coincide with the dark lines 

 in the spectrum, and to Kirchhoff and Bunsen 

 is due the credit of applying this method 

 of research to astronomical science. They 

 arranged their apparatus so that one-half was 

 lighted by the Sun, the other by the incan- 

 descent gas they were examining. "When the 

 vapour of sodium was treated in this way they 

 found that the bright line in the flame of soda 

 exactly coincided with a line in the Sun's 

 spectrum. The conclusion was obvious ; there 

 is sodium in the Sun. It must, indeed, have 

 been a glorious moment when the thought 

 flashed upon them; and the discovery, with 

 its results, is one of the greatest triumphs of 

 human genius. 



The Sun has thus been proved to contain 

 hydrogen, sodium, barium, magnesium, cal- 

 cium, aluminium, chromium, iron, nickle, man- 

 ganese, titanium, cobalt, lead, zinc, copper, 

 cadmium, strontium, cerium, uranium, potas- 



