326 NINETEENTH CENTURY. pt. hi. 



hofer had pointed out, because the lines are different in 

 light which comes from the stars, showing that in that case 

 it has passed through Other kinds of gases. Therefore 

 Kirchhoff concluded that round the solid or liquid body of 

 the sun, which gives out white light, and would of itself pro- 

 duce a continuous spectrum, there must be an atmosphere of 

 gases of different kinds, w^hich absorb or destroy particular 

 rays of light, and prevent them reaching us. 



If this is the case, it is clear that we can tell from the 

 lines in the spectrum what gases and vapours there are in 

 this solar atmosphere. For example, there must be sodium 

 which cuts off the rays which ought to come to D, and there 

 must be also iron, magnesium, calcium, chromium, potas- 

 sium, rubidium, nickel, barium, lead, copper, zinc, strontium, 

 cadmium, cobalt, uranium, cerium, vanadium, palladium, 

 aluminium, titanium, and hydrogen, for the bright lines of 

 all these metals are replaced by dark lines in the solar 

 spectrum, showing that the white light from the body of the 

 sun must have passed through their gases. 



Dr. Hnggins and Dr. Miller examine the Stars by 

 Spectmm Analysis, 1862. — Only a few months after Kirch- 

 hoff had proved that the black lines in the solar spectrum 

 reveal to us what elements exist as gases around the sun, 

 two English chemists. Dr. Miller, who died a few years ago, 

 and Dr. Huggins, who is still living, began to try the same 

 experiments with the other heavenly bodies, and the study 

 has since been carried still farther by Mr. Lockyer. 



Their instruments were now much more perfect than 

 those which Fraunhofer had used, and they were able to see 

 the effects of our own atmosphere upon sunlight, for when 

 the sun is setting and its light has to pass through a long 

 layer of air before it reaches us, faint lines appear on the 



