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, zine, copper, 
cadmium, strontium, cerium, uranium, potas- 
