70 



A. W. Steivart on 



same state as in the electric arc and in addition there were signs 

 of the presence of carbon. In the next hotter stars, no carbon 

 was detected, but most of the metals were spectroscopically 

 recognisable as being in the same condition as in the electric 

 spark. In the next set, of still higher temperature, many of the 

 metals were absent and the two elements hydrogen and helium 

 a])pe'ired in considerable strength. Finally, in* the hottest, 

 gaseous stars, no metallic traces are found ; hydrogen and helium 

 were strongly marked and in addition there were lines in the 

 spectra which corresi)ond to no elements known upon the surface 

 of the earth. Lockyer symbolised this somewhat after the 

 following fashion : 





GASEOUS STARS. | 





(Hydrogen, 



helium and 





unknown 



elements). 





HIGH TEMPERATURE 



HIGH TEMPERATURE 



o 



STARS 



STARS 



j!5 



(Few Metals present) 



(Few Metals present) 



p^ 



A 



V 



a; 



1\IEDIUM TEMPERATURE 



MEDIUM TEMPERATURE 



STARS 



STARS 



H 



pi 



(Metals in "spark" state; 



(Metals in "spark" state; 





No Carbon ])resent) 



A 



No Carl)on present) 

 V 



r-i 



LOW TEMPERATURE 



LOW TEMPERATURE 





STARS 



STARS 





(Metals in "arc " state ; 



(Metals in "arc" state; 





Carl)on present) 



Carbon present) 





A 



V 





COLD METEORS 



COLD STARS 



Thus according to Lockyer's hypothesis, the stars present us with 

 a picture of the evolution of the elements. At first there are 

 the cold meteors, having a composition very like that of the 

 Earth. Then, with rise in temperature, due to inter-collisions 



