ARGTOWSKI, CHANGES IN DISTRIBUTION OF TEMPERATURE 73 



of maritime climate.. One may say, therefore, that the big pleionian 

 variations of Europe are a purely continental and, perhaps, Arctic 

 phenomenon. 



It would be premature to attach any importance to the locations of 

 origin of particular pleions. The areas where they are formed, in situ, 

 are probably not always the same. Besides, the question whether a pleion 

 is of an Asiatic or arctic origin has no importance for the present, simply 

 because it would be absolutely premature to discuss the reasons why, 

 under the influence of a temporary increase of solar radiation, one loca- 

 tion of the polar or temperate regions is more favored than others. 



It is evident that a temporary increase of energy radiated to the earth's 

 surface, during, let us say, three months in succession, will not directly 

 influence the temperature of the arctic regions if it occurs during the 

 winter months of the northern hemisphere, whereas the antarctic regions 

 will be greatly influenced. 



The question of the formation and development of pleions, outside the 

 equatorial regions, must be studied together with the seasonal changes 

 of atmospheric pressure and the temporary alterations of. atmospheric 

 circulation, nebulosity, rainfall, etc. I intend to make such a study for 

 particular pleions and especially for brachypleions. The fact, however, 

 that in Eussia there are some striking coincidences between the forma- 

 tion of pleions and the crests of the Arequipa curve is a most convincing 

 proof of a common cosmical cause of these variations. 



American Temperature Data for 1900-1909. 



Since the equatorial or Arequipa variations of temperature can be ob- 

 served not only in Russia but also along the Atlantic coast of the United 

 States, in New York in particular,^^ it was really fascinating to follow 

 more closely the changes in the distribution of temperature which oc- 

 curred simultaneously in different regions of the North American con- 

 tinent. Here, it was possible to follow the phenomenon from ocean to 

 ocean, over a much more extensive area than that of central Europe, and, 

 this area being more isolated, it is self-evident that more definite results 

 were obtainable. 



A research, apparently similar to mine, was made long ago by Helm 

 Clayton.^® It was only after my investigations were nearly completed 

 that I noticed the fact and Clayton's writings have therefore not at all 

 influenced my work. Clayton studied the monthly departure maps pub- 



1* H. Arctowski : "On some cHmatIc changes recorded In New York City." Bull. 

 Amer. Geogr. Soc, Vol. 45, p. 117. New York, 191.3. 



" H. Helm Clayton : "Weather changes of long period." Amer. Meteor. Journ., Vol. 

 2, p. 126. Detroit, 1885. 



