24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



intensities. The data were taken from World Weather Records, 192 1- 

 1930. The results are given in table 4 on page 42 for each season and 

 in table 5 on page 49 for the mean for the four seasons — that is, for 

 the year. 



Referring to table 5, the first step in investigating the relationships 

 was to determine the correlation between the means of departures of 

 pressures corresponding respectively to equal departures of solar 

 radiation above and below normal. The results are as follows : 



Correlation betivecn the Mean Departures of Pressure Corresponding 



Respectively to Equal Departures of Solar Radiation 



Above and Below Normal 



Correlation coefficients 



Northern Southern 



Departures of solar radiation Hemisphere Hemisphere 



+.001 to +.005 and —.000 to —.005 r= — 0.35 r =r — 0.51 



+.006 to +.010 and —.006 to —.010 r = — .38 r=— .72 



Over +.010 and under —.010 /■ = .27 r=— .23 



Number of stations used A'^ = 1 19 stations N ^^ 46 stations 



The meaning of this table is that for equal departures of solar 

 radiation above and I)elow normal the departures of pressure from 

 normal in all parts of the world tend to have opposite signs. This 

 relation holds for stations all over the world, not only in the means for 

 the year, taken from table 5 as here given, but also in general with a 

 few exceptions for the separate seasons given in table 4. This fact 

 seems to leave no escape from the conclusion that this is a real and not 

 an accidental relationship. In short, these extensive data, covering all 

 parts of the world, prove that solar variation is an important weather 

 factor, even the dominating one, as also appears from Figs. 13 and 14 

 and 23-26. 



Figure 20 shows the areas of excess and of defect of pressure for 

 three different values of solar radiation above normal, and figure 21 

 shows the areas for the different values of solar radiation below nor- 

 mal. The departures of radiation above and below normal were taken 

 as nearly equal as possible. These charts show numerous centers of 

 plus and of minus departures of pressure which appear to be related 

 in the successive charts. For example, in figure 20 the upper chart 

 ( I ), for solar radiation above + .010 calories, shows an area of excess 

 pressure over Greenland and Labrador. In the next chart (2), for 

 + .006 to +.010 calories, this area has extended southward with the 

 center of greatest departure near Nova Scotia ; and in the third chart 

 (3), for +.001 to +.005 calories, the center of excess pressure is 

 over the ocean to the south of Nova Scotia. In fissure 21, with solar 



