and JDepartures in the United States. 



123 



summer beincj cooler. The minimum solar action is followed 

 by warmer seasons in the United States, a o:reater amplitude 

 in the circulation of the warm and cold areas, and a more pro- 

 nounced system of warm leakage currents from the Grulf of 

 Mexico upon the Mississippi Valley. It is, also, seen that the 

 succession of minor crests is usually about three years, this 

 being the 3-year period lirst described by Bigelow in 1894. 



Fig. 3. 



Lat 90° 80' 70° 60° 50° 4-0° 30° 20° 10° 0° I 



Height 

 16000 



15000 



14000 



13000 



12000 



IIOOO 



10000 



9000 



8000 



7000 



6000 



5000 



4000 



3000 



2000 



1000 



000 







Z20' 





2/0° 









2/0° 









1 



1 





1 







/ 



/ 















/ 







/ 











1 





/ 



1 





/ 











220' 







/ 





/ 



/ 









220' 







/ 



/ 





/ 



/ 



r^ 













/ 





/ 



/ 



/ 









230° 





/ 



/ 



1 



/ 



/ 



^ 











2l(t 



/ 





/ 



/, 



/ 



















/ 



/ 



/ 











24d° 





/ 





/ 







/ 







. 





250° 



2/0° 



/ 



/ 



/ 



// 



/ 















/ 



/ 



'/ 



/ 



/ 







-.^ 





260° 



■2?0' 





/ 



/ 

 J 



7 



/ 











270° 



230' 



/ 



/ 





/ , 



/ 











2S0° 





/ 



/ 



/ 



/ 



/ 



/ 











240' 



/ 



/ 



/ 



/ 



/ 



/ 









290' 



250° 260° 270° 280° 290° T m\ 



Fig. 3, The location of the mean annual isotherms in the earth's 

 atmosphere. 



The Cause of the Inversion of Temperatures. 



In order that the cause of this important inversion of tem- 

 peratures in the United States may be better i;nderstood, I 

 will produce from my other unpublished studies on the Gen- 

 eral Circulation a diagram of the distribution of the mean 

 annual temperatures in the atmosphere, as derived from balloon 

 and kite ascensions, and from a study of the equations of 

 motion. The vertical scale of the drawing is greatly magni- 

 fied in fig. 3, in order to bring out the fundamental facts. 



