62 ABSORPTION AND EMISSION. 



been made by Kirchoff, and he has thereby ascertained that 

 sodium, bismuth, magnesium, chrome, nickel and iron, all exist 

 in the Sun. The metals, gold, silver, mercury, tin, lead, 

 aluminium and silicum, on the other hand, do not exist in 

 the Sun, their specific rays being wanting in the solar spec- 

 trum. 



