CHAPTER II 



THE SUN AND THE PHYSICOCHEMICAL ORIGINS 



OF LIFE 



Heat and light. Chemical '' life elements " as they exist in the sun. Primor- 

 dial environment — electric energy and the sun's heat. Capture of the 

 energy of sunlight. Action and reaction as adaptive properties of the 

 life elements. Interaction or coordination of the properties of the life 

 elements. Adaptation in the colloidal state. Cosmic properties and life 

 functions of the chief chemical life elements. Pure speculation as to the 

 primary physicochemical stages of life. Evolution of actions and reac- 

 tions. Evolution of interactions. New organic compounds. 



We will now consider the sun as the source of heat, light, 

 and other forms of energy which conditioned the origin of life. 



Heat and Light 



It is possible that in the earher stages of the earth's history 

 the sun's light and heat may have been different in amount from 

 what they are at present; so far as can be judged from the 

 available data it seems probable that, if perceptibly different, 

 they were greater then than now. But if they were greater, 

 the atmosphere must have been more full of clouds — as that of 

 Venus apparently is to-day — and have reflected away into space 

 much more than the 45 per cent of the incident radiation which 

 it reflects at present. On the earth's surface, beneath the cloud 

 layer, the temperature need not have been much higher than 

 the present mean temperature, but was doubtless much more 

 equable, with more moisture, while the amount of sunlight 

 reaching the earth's surface may have been less intense and 

 continuous than at present. 



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