8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



ture departures for each of the two stations, when the regularity of 

 the periods was little disturbed during the whole month. Months 

 were chosen fairly well distributed throughout the year. Plots of 

 these temperature departures are given in figure 2. By drawing 

 straight lines across the bottom of each hump, values have been read 

 off giving roughly the numbers of degrees by which the temperatures 

 were raised by the solar influence. As is well known, the tempera- 

 ture changes of all sorts are much less in July than in the cooler 

 months of the year, in the Eastern United States. Hence it is not 

 surprising that this appears in figure 2 and in table 3. 



Table 3. — Average magjiitiide of the temperature 

 fluctuations in degrees F. 



New York Washington 



Jan. 1932, i2?6 Feb. 1928, I5?2 



Mar. 1936, I4?2 Mar. 1946, i4?o 



July 1938, 7?8 Nov. 1943, i2?4 



By inspection of these exhibits one sees that throughout most of 

 the year, in Washington and in New York, the temperature is af- 

 fected either four or five times each month by a change in solar 

 radiation, by amounts ranging from 10° to 20° F. 



CONCLUSION 



Contrary to the suggestion referred to at the beginning of this 

 paper, Washington and New York respond almost alike to the short 

 regular variations of solar radiation. Two such variations are known. 

 The primary one has a period of 6.6485 days, and the subordinate 

 one half that length. Thus the primary solar change recurs either 

 four or five times each month. Temperature changes of 10° to ;:o° F. 

 attend its every recurrence during most months of the year, but dur- 

 ing summer the effect is somewhat less. The phases of the tempera- 

 ture changes appear to be the same at Washington and New York. 



