12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 95 



accurate results depend on the use of the " short method." This is 

 empirical, and is based on several hundred solar-constant observations 

 by the " long method " as we now call the fundamental method of 

 Langley. Thus the " establishment " of a station requires several 

 years. If funds were now available, the stations could begin observing 



MEAN RESULTS 1924-1935 



SOLAR VARIATION AND TEMPERATURE DEPARTURES, HELENA, MONT. 



Fic. 6. — Oppositeness of temperature departures at Helena which follow average 

 rising and falling sequences of solar variation. 



early in 1938, but the " short method " tables and necessary investiga- 

 tions of weather relationships at many stations would not be com- 

 pleted for forecasting purposes before the end of 1939. 



I have thought of another method which may be practicable for 

 following solar changes. As indicated by figure i, page 29 of vol- 

 ume 5, Annals of the Smithsonian Astrophysical Observatory, the 



