NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC 273 



For the months examined in the year 1913, Dr. Clayton thinks 

 that he finds a period of about 22 days in the solar radiation as well 

 as in the temperature at Buenos Aires, and, especially in the solar 

 radiation he finds another shorter period of between 11 and 14 days. 



Dr. Clayton sums up the results of his investigations thus : 



" I. There is an intimate relation between the solar changes and 

 meteorological changes of short period. 



" 2. There is a class of meteorological changes which have their 

 origin in equatorial regions, and by a transference of air probably 

 in the upper layers, are felt within a few days in higher latitudes. 

 These changes are the complement of the complex meteorological 

 drift which goes from west to east in temperate latitudes with a 

 component of motion from Pole to Equator in both hemispheres." 



Dr. Clayton does not expressly say whether, according to his view, 

 the positive correlation in the arctic regions is directly due to the 

 variations in the solar insulation, or whether it may be due to the 

 above-mentioned transference of air from the equatorial regions 

 probably in the upper layers which should be felt " within a few 

 days in higher latitudes." 



DR. Clayton's values of the correlation factor are not directly 



DUE TO THE EFFECT OF SOLAR RADIATION ON TERRESTRIAL TEM- 

 PERATURE, BUT TO ITS EFFECT ON THE DISTRIBUTION OF PRESSURE. 



It is evident that though the correlation factors found by Dr. Clay- 

 ton are not very great, still most of them are perfectly certain. We 

 do not, however, agree with the author that according to his inves- 

 tigations the regions with positive correlation and the regions with 

 negative correlations may be assumed to be arranged in belts round 

 the globe. By considering the correlations between the daily varia- 

 tions of solar activity and of temperature at the earth's surface at 

 the 30 stations investigated by Dr. Clayton, we come much more 

 to the conclusion that the occurrence of positive or negative cor- 

 relations at these stations depends chiefly on their situation with 

 regard to the centers of pressure maxima and minima of the atmos- 

 phere, in the same way as we have found it to be the case with the 

 monthly and annual variations of temperature at the earth's sur- 

 face in the various regions of the globe. 



As the temperature of a region is essentially influenced by the 

 prevailing winds, i. e., by the mean barometric gradient, we must 

 expect that in regions where the normal temperature is low as com- 

 pared with neighboring regions in the same latitude, an increase 



