LIFE ELEMENTS IN THE SUN 45 



To sum up, if the primordial atmosphere contained more 

 aqueous vapor and carbon dioxide than at present, the greater 

 cloudiness of the atmosphere would have very considerably in- 

 creased the albedo, that is, the reflection of solar heat, as well 

 as hght, away into space. If the earth's surface was covered 

 with loose debris, it would have retained more of the solar heat 

 which reached it directly ; but, with such an atmosphere as is 

 postulated, very Httle of the solar radiation would have reached 

 the surface directly. What is true of the indirect access of the 

 supply of light from the sun would also be true of the supply 

 of heat. On the other hand, the greater blanketing power of 

 the atmosphere would tend to keep the surface as warm as it 

 is now, in spite of the smaller direct supply of heat. 



It is also possible that, through the agency of thermal 

 springs and the heat of volcanic regions, primordial life forms 

 may have derived their energy from the heat of the earth as 

 well as from that of the sun. This is in general accord with 

 the fact that the most primitive organisms surviving upon the 

 earth to-day, the bacteria, are dependent upon heat rather 

 than upon light for their energy. 



We have thus far observed that the primal earth, air, and 

 water contained all the chemical elements and three of the 

 most simple but important chemical compounds, namely, 

 water, nitrates, and carbon dioxide, which are known to be 

 essential to the bacterial or prechlorophyllic, and algal and 

 higher chlorophyllic stages of the life process. 



Chemical "Life Elements" as They Exist in the Sun 



An initial step in the origin of life was the coordination or 

 bringing together of these elements which, so far as we know, 

 had never been chemically coordinated before and which are 



