NO. 7 



THE ATMOSPHERE AND THE SUN CLAYTON 



convinced that meteorological cycles change both in amplitude and 

 phase. (Science, 1898, p. 243.) 



Figure 2t, shows an analysis of the Wolfer sun-spot numbers 

 between 1890 and 1913 into a period of 22.6 years and its harmonics. 

 It is seen that the chief period is one of 11.3 years, but some of the 

 other periods show a fairly large amplitude of oscillation. 



Fig. 23. — Harmonic analysis of 22.6-year sun-spot period, 1890-1913. 



The meteorological data at more than a hundred stations in various 

 parts of the world were analyzed in the same manner. Figures 

 24, 25, 26, and 2y show lines of equal departure of pressure for the 

 various periods at the time of maxima of the solar periods of the 

 same length. A chart showing the departures at the time of the 

 solar maxima of the 7.5 year period is given in figure 17. 



