76 ORIGIN AND NATURE OF LIFE 



relationship to known hydrogen lines, and 

 supposed to be precursors of that element. 

 The other predominant lines at this level of 

 stellar temperature and evolution, are those 

 of hydrogen as seen terrestrially when hydro- 

 gen is sparked with an electric coil in a vacuum 

 tube. Much fainter lines are seen of helium, 

 proto-magnesium, and proto-calcium. No lines 

 of iron are visible here, even in the proto- 

 form. Next come stars of the helium group, 

 where the spectrum of that gas is prominent, 

 associated still with hydrogen, and the spectral 

 lines of proto-carbon, oxygen, and nitrogen 

 are now clearly present. 



In the proto-metallic stars, the precursors 

 of such metals as iron, copper, manganese, 

 nickel, titanium, and calcium, make their 

 prominent appearance. 



When the metallic spectra are reached such 

 lines as distinguish calcium, iron, and man- 

 ganese in the ordinary voltaic air-arc are 

 present, while many of the proto-lines become 

 dimmer and disappear. Lastly, the fluted 

 spectra appear, of carbon or manganese, with 

 fainter metallic lines. 



It is thus seen that the more primordial 

 constituents of matter are those formed in the 

 hottest stars, and that as temperature falls 

 the ordinary elements become synthesized. 



