14 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 87 



^2 



+ / 







-I 



+2 

 + 1 

 

 -I 

 -2 



1-2 

 + 1 





 -I 



-z 



Fig. 8. — A retrograde temperature departure forecast from 1924 backward 

 1918-1916. Based on average periodicities in departures 1918-1930. 



