164 ANNtTAL RfiPOET SMITHSONIAN INSTITUTION, 1933 



Figure 7 shows such a curve, freed from all atmospheric absorp- 

 tion, freed also from all instrumental absorption, and reduced from 

 the prismatic to the normal or wave-length scale. Here the visible 



° 2 



3 . 



3^ 2 



part shrinks greatly in length but grows greatly in height relatively 

 to the infrared. Compare this solar energy curve, if you please, 

 with the energy curve of a perfect radiator of the temperature of 



