. The origin and evolution of life, on the theory of action, reaction and interaction of energy. robable 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 ofVenus apparently is to-day—and have reflected away into spacemuch more than the 45 per cent of the incident radiation whichit reflects at present. On the earths surface, beneath the cloudlayer, the temperature need not have been much higher thanthe present mean temperature, but was doubtless much moreequable, with more moisture, while the amoun
. The origin and evolution of life, on the theory of action, reaction and interaction of energy. robable 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 ofVenus apparently is to-day—and have reflected away into spacemuch more than the 45 per cent of the incident radiation whichit reflects at present. On the earths surface, beneath the cloudlayer, the temperature need not have been much higher thanthe present mean temperature, but was doubtless much moreequable, with more moisture, while the amount of sunlightreaching the earths surface may have been less intense andcontinuous than at present. 43 44 THE ORIGIN AND EVOLUTION OF LIFE The following are among the reasons why the primordialsolar influences upon the earth may have differed from thepresent solar influences. It appears probable that the lifelesssurface of the primordial earth was like that of the moon—covered not only with igneous rocks but with piles of heat-stor- HEAT LIGJ Billion vibratijlds per secondnn/^^ CHEMrC4L. WIRA VIOLET Fig. 3. Light, Heat, and Chemical Influence of the Sun. Diagram showing how the increase, maximum, and decrease of heat, Hght, and chemicalenergy derived from the sun correspond to the velocity of the vibrations. After UlricDahlgren. ing debris, as recently described by Russell ^—and if, like themoon, the earth had had no atmosphere, then the reflectingpower of its surface would have represented a loss of only 40per cent of the suns heat. But a large amount of aqueousvapor and of carbon dioxide in the primordial atmosphere prob-ably served to form an atmospheric blanket which inhibitedthe radiation from the earths surface of such solar heat as pen-etrated to it, and also prevented excessive changes of temper-ature. Thus there was on the primal earth a greater reg-ularity of the suns heat-supply, with more moisture. J Russell, H. N., 1916, p. 75. LIFE ELEMENTS IN THE SUN 45 To
Size: 2104px × 1187px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyorkcscribnerss
