l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



Table 5. — Periodic Analysis of Washington Temperature Departures — (cont'd) 



Periodicities 

 Degrees x 10 Fahr. 



68 ni 45 111 25 m 18 m 11 m 



1930 Jan —7 I o 14 —2 



Feb — 8 o — 3 19 o 



Mar —9 —1 — S 21 3 



April — 10 — 3 — 7 16 8 



May — II — 6 — 8 7 10 



June — 12 — 9 —9 — 4 o 



July —13 ^10 — 7 — 12 — 2 



Aug —14 —10 — s —14 5 



Sept —14 ^11 —3 —14 i^ 



Oct — IS —II —I — 9 10 



Nov —15 —10 3 —4 —4 



Dec —15 —9 80—2 



at some special speeds, there are sometimes encountered " sym- 

 pathetic " vibrations due to the make-up of the car itself. 



After all, the contribution of the i8-month periodicity to the fit 

 between curves A and B is a minor feature. Is not their surprising 

 agreement, which would still be striking if the 1 8-month curve F were 

 omitted, significant because related to solar phenomena? Is it not 

 indeed of promising import from the standpoint of long-range weather 

 forecasting ? 



SUMMARY 



1. Contrary to the prevailing view, the weather appears to be gov- 

 erned by variations in solar radiation. 



2. Long-continuing periodicities in solar variation are found which 

 give promise of value for purposes of long-range weather forecasting. 

 They appear to be submultiples of 1I5 and 33 years. 



3. All of these periodicities are found in Washington temperature- 

 departures, and, combined, suffice to represent its main features. 



