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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 68 



correlation belt of the north extends far to the south, owing to the 

 increase of winds from the direction of the equator arising from 

 the increase of pressure over the Atlantic near the 35th parallel. 



CORRELATION OF SOLAR RADIATION WITH ATMOSPHERIC 



PRESSURE 



To ascertain to what extent the pressure responded to tempera- 

 ture changes the next step was to determine the correlation of the 

 solar radiation with changes in atmospheric pressure. The observa- 

 tions of pressure made nearest 2 p. m. of each day at a few selected 

 stations were treated in the same manner as in the case of the tempera- 

 ture. Mean values were obtained for each day by interpolation 

 between monthly means, and these means were subtracted from the 

 observed values to obtain the plus and minus departure showing the 

 short period changes in pressure. These departures were then corre- 

 lated with the short period changes of solar radiation and the results 

 are given in table 6. 



Table 6. — Correlation of Solar Radiation with Pressure in Various Zones of 

 the Earth from 5-Day Means 



These various values of the correlation factor are plotted in 

 figure 4. 



