222 



A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 

 TABLE III— Continued. 



These data have been constructed in the charts 49 and 50, with the two 

 years of observation overlying the same abscissas to bring out the contrasts. 

 The series for October, 1902-October, 1903, are easily distinguished from the 

 later series, October, 1903-October, 1904, b}- the continuous curves. The 

 nucleations are given in thousands (m~'''^). Clear, partly cloud)-, and cloudy 

 weather are indicated on the curves by the visual Weather Bureau syml^ols — 

 O, 3, #. Rain is shown by r. 



Apart from details, the striking difference of time changes of nucleation, 

 1902-03 and 1903-04, are apparent. In both cases the high winter nucleations 

 as compared with the summer nucleations are the essential feature; but in 1903 

 these nucleations fall off almost suddenl}- and pennanently in March, whereas 

 the change in 1904 beyond March is much more gradual. 



36. Mean monthly nucleations. — The character of these secular changes 

 will, however, a]jpear much more clearly in the monthly averages given in 



Table IV. 



TABLE IV. 

 Mean Monthly Nucleations from October, 1902. to October, 1904. 



