NO. 6 PREDICTION OF WASHINGTON TEMPERATURE I948 ABBOT 3 



heit between the two means of departures just indicated. For this 

 prediction I take vakies from the three years 1945-46-47, selected as 

 specified in the next preceding paragraph. The computed differences 

 of these means are as follows : 



1945, 6?6; 1946, 8?6; 1947, 6?o; Mean, 7?i 



I predict the "Mean" just stated, for 1948. 



Should the method of prediction succeed in Washington, it will 

 probably succeed equally well in all other places. If any should be 

 bold enough to use it, and wish to estimate how much difference in 

 temperature between predicted maxima and minima is to be expected, 

 he should consult figure 5 of the publication above cited and note 

 that the range between maxima and minima varies several fold in 

 Washington for the various months of the year. 



VERIFICATION OF THE PREDICTION 



January 19, 1949- 

 This is to certify that I have caused examination to be made of 

 the sealed package deposited by Dr. C. G. Abbot in the Smithsonian 

 safe in January 1948. I have tabulated the temperature departures 

 from normal at Washington on the 55 dates specified therein, and 

 the temperature departures at the warmest dates intervening between 

 the 55 pairs, all as published in Weather Bureau Form 1030. I find 

 that on 48 occasions warmer dates occurred between the dates speci- 

 fied, and that for the entire series of 55 dates the mean excess found 

 thus was 6^96 F., as compared with 7?i F. predicted by Dr. Abbot. 



L. B. Aldrich, 

 Director, Astrophysical Observatory. 



COMMENTS 



The test proposed in the preceding pages came out nearly as ex- 

 pected. But I realized soon after the manuscript was deposited, in 

 January 1948, that the test might perhaps give an exaggerated im- 

 pression of the amplitude of the 6.6456-day temperature fluctuation. 

 For by using the highest temperatures which intervened between 

 the predicted dates of minimum temperatures at Washington, there 

 can be no question that some of these higher temperatures are made 

 higher than they otherwise would be by local terrestrial meteorologi- 

 cal influences, not directly caused by the solar periodic variation. 

 Such extraneous influences may, it is true, have correspondingly 



