THE UPPER ATMOSPHERE — ^DOBSON 



189 



the temperature at all levels. The vertical distribution of oxygen 

 can be assumed without any great error, and the distribution of the 

 ozone has been measured, but we are still without reliable knowledge 

 of the amount of water vapor at heights above 20 kilometers. As- 

 suming various distributions of these gases Dr. Gowan has calcu- 



^ c^ :| ^ 



_LJ LJ I I 1 L—L 



FiGDRE 3. — Annual variation of ozone. Tlie curves sliow the smooth annual variations 

 in the total ozone content of the atmosphere over different parts of the world. The 

 points represent the mean monthly observed values. Note that the amount of ozone 

 is large in spring and small in autumn in both hemispheres. [Figures 3, 4, 5, and 6 

 are reproduced from the Proceedings of the Royal Society by permission of the Council.] 



lated what would be the temperature of the air at great heights. 

 His results show that there should be a marked rise of temperature 

 of the air in the region about 40 kilometers, agreeing reason- 

 ably well with the actual temperatures found from sound-wave 

 observations. 



The ozone in the atmosphere. — Both oxygen and ozone are re- 

 sponsible for causing the air to be warm at great heights, but the 



