274 '^ SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. yo 



of the gradient will cause a sinking of the temperature, while in 

 regions with comparatively high normal temperature an increase of 

 the gradient will cause a rising temperature. 



We must consequently conclude that at all stations, whether in 

 the tropics, or in the temperate zones, or in the arctic regions, 

 the fluctuations in the solar activity, by effecting changes in the 

 distribution of air pressure and in the circulation of the atmosphere 

 will cause changes of the temperature at the earth's surface accord- 

 ing to the situation of the place. Let us examine some of Dr. 

 Clayton's stations from this point of view. Pilar, in Argentina, is 

 situated far outside the tropical regions in 31° 39' S. 63° 5' W, 

 It should consequently, according to Dr. Clayton's theory, be ex- 

 pected to have a negative correlation, but it has a comparatively 

 well developed positive correlation. This station is, however, dur- 

 ing the months of July to November, situated on the western side of 

 the center of action (the high pressure region of the South Atlan- 

 tic). An increase of this pressure maximum, by increased solar 

 activity, might therefore be expected to bring more northerly winds 

 and consequently higher temperatures in this region. 



Another station, Bathurst, in Gambia, on the west coast of Africa, 

 is situated well inside the tropics, in latitude 13° 24' N. 16° 36' W., 

 and might consequently, according to Dr. Clayton's views, be ex- 

 pected to have positive correlation ; but he finds it nevertheless to 

 have a very well developed negative correlation. This is, however, 

 easily understood, considering that the station is situated on the 

 so'utheastern side of the North Atlantic pressure maximum, in the 

 region of the northeastern trade winds. An increase of the cen- 

 ter of action, by increased solar activity, will increase the trade winds 

 and lower the temperature. 



At the station Zimgeru in Nigeria, 9*^ 49' N., and 6° 10' E., the 

 correlation is, however, positive. In this region there are probably 

 no very strong prevailing winds during autumn, and an increased 

 solar .activity may raise the temperature. The normal tempera- 

 ture of this region, during the months of July to November, is 

 also comparatively high for its latitude, while Bathurst has a com- 

 paratively low temperature. San Diego and Sacramento, in Cali- 

 fornia (in 32° 43' N. and in 38° 35' N.), are situated on the 

 eastern side of the center of action (the pressure maximum of the 

 North Pacific) during the months July to November, and cold 

 northwesterly winds are therefore prevailing, which when increased 

 by increase of the sun's activity, will lower the temperature. At 



