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ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 5 



effect of oxygen is gi-ecatest in the upper parts of the warm region, 

 while the effect of the ozone is greatest in the lower parts of that 

 region. A point of great interest is that while the amount of 

 oxygen is constant, the amount of ozone varies greatly. Further, 

 these variations in the amount of ozone are found to be closely asso- 

 ciated with the weather conditions as seen on the weather maps for 



Latitude 



Ldt/tude 



FiGDEB 4. — Variation of ozone with latitude. The curves depend on the same observa- 

 tions as were used for figure 3, but now arranged to show the variation of the ozone 

 content with latitude. Note the rapid increase toward polar regions in spring. 



ground level. The total amount of ozone in the atmosphere is very 

 small, but since it absorbs the ultraviolet part of sunlight very 

 strongly, its effects are of great importance. How very small the 

 amount of ozone is may be seen in the following way: If all the 

 air in the atmosphere were formed into a layer of uniform density, 

 equal to that of surface air, there would be a layer 8 kilometers 

 deep. 



