14 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 7I 



factors for the relation between the solar radiation and the tempera- 

 ture of Buenos Aires have been computed month by month for each 

 half -day up to lo days following the observations beginning with 

 August, 1918, and extending to May, 191 9. The results are shown 

 in table VI. 



Table VI. — Correlation Between Solar Radiation and the Temperature at Buenos Aires. 

 Month by Month {August. 1918-May, 1919) 



* Minima. 



In investigating the relation between the Wolf sun-spot numbers 

 and the pressure, Mr. Nils Hessling and I have found an annual 

 change in the correlation factors for central Argentina as shown by 

 the following figures in which the numbers following the words 

 " sun spot " show the correlation of the monthly mean pressures at 

 Cordoba with the sun spots from 1875 to 191 5 ; and the numbers fol- 

 lowing " radiation " show the correlation of Abbot's radiation values 

 with the temperature at Buenos Aires three and one-half days later. 



Jan. F'jb. March Apr. May June July Aug. Sept. Oct. Nov. Dec. 



Sun spot —.09 -f-.2i —.13 4-.6i -f.33 -f .28 -I-.34 4-.OS -f .11 —.16 -f .01 —.07 

 Radiation +.60 -|-.I7 —.36 —.07 -|-.I2 . . . . —.20 — .10 — .09 —.12 -I-.37 



During the interval April to September when the sun is in the 

 northern hemisphere, the correlation factors show that the pressure 

 at Cordoba oscillates with the sun spots ; but when the sun is in the 

 southern hemisphere the pressure tends to be low when spots are 

 numerous and vice versa. 



In the case of solar radiation, the temperature at Buenos Aires 

 during the summer months December to February increases when 

 the solar radiation increases, reaching a maximum three to three and 

 one-half days latejf ; but during the remainder of the year the reverse 



