2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



numerals, in other words the "preferred days" for 1949. These 

 preferred days should give, on the average, higher precipitation 

 ])er day than all the other days of the year, but there is no high 

 probability that precipitation will actually fall on any individual day 

 among "preferred days," or will not fall on any individual other day. 



Table 2. — Predicted dates when average daily precipitation should exceed 



average daily precipitation for all other dates in Washington, D. C, 



for the year 1949 



"Preferred" „ ,, « -.i t 



cycle places Jan. Feb. Mar. Apr. May June 



I 24 20 19 15 12 8 



II 25 21 20 16 13 9 



III 26 22 21 17 14 10 



IV 27 23 22 18 IS II 



V 1,28 24 23 19 16 12 



XII 8 4 3 26 23 19 



XIII 9 5 4,31 27 24 20 



XV II 7 6 2, 29 26 22 



XVII 13 9 8 4 1,28 24 



XVIII 14 10 9 5 2,29 25 



XXII 18 14 13 9 6 2,29 



XXVI 22 18 17 13 10 6 



XXVII 23 19 18 14 II 7 



"Preferred" _ 



cycle places July Aug. Sept. Oct. Nov. Dec. 



I 5 1.28 24 21 17 14 



II 6 2,29 25 22 18 15 



III 7 3,30 26 23 19 16 



IV 8 4, 31 27 24 20 17 



V 9 5 1, 28 25 21 18 



XII 16 12 8 s 1,28 25 



XIII 17 13 9 6 2,29 26 



XV 19 15 II 8 4 1,28 



XVII 21 17 13 10 6 3,30 



XVIII 22 18 14 II 7 4,31 



XXII 26 22 18 15 II 8 



XXVI 3, 30 26 22 19 15 12 



XXVII 4,31 27 23 20 16 13 



The statistical tabulation of 27-day cycles, on which table 2 is 

 based, began January i, 1924, and it indicated that the true cycle is 

 27.0074 days. In 25 years since December 31, 1923, there were 

 9.132 days. In 339 cycles of 27.0074 days there are 9,155.50 days, 

 or in round numbers 23 days more than in the years 1924-1948. 

 Hence the first day of the 340th cycle begins on January 24, 1949, 

 as given in table 2, corresponding to Roman numeral I. 



It should be emphasized that this prediction relates only to Wash- 

 ington, D. C- 



2 This paper was finished on January 18, 1949, immediately after receipt of 

 \\'eather Bureau data for December 1948. 



