108 



ANNALS NEW YORK ACADEMY OF SCIENCES 



January, 1904, to October, 1904,-September, 1905, the Grirasey curve 

 shows all the crests and depressions of the Arequipa curve slightly re- 

 tarded. Jacobshavn, on the contrary, is in advance of Arequipa. 



Grimsey is a small island situated on the Polar Circle, north of Ice- 

 land, and the latitude of Jacobshavn is 69° 13' N. Both of these stations, 

 therefore, are under the influence of polaf currents and polar ice. 



If the consecutive temperature curves of these stations display simi- 

 larities with the Arequipa curve, and, in consequence also with those of 

 Bulawayo and Mauritius, we must admit that it is absolutely out of the 

 question to search for an explanation of these variations in the changes 

 of polar ice conditions. 



'J'ho second question could not be jinswered by a simple inspection of 



Fig. .59. — Temperature rariationi^ in the Azores, Madeira and Cape Verde Isl. 



the departures given in Table VI and the curves of consecutive means 

 of Figs. 59 and 60. Therefore, I have drawn maps showing tlie probable 

 connections between the European and American pleions. The ma]) for 

 1909, which I reproduce here (Fig. 61), may serve as an example. 



On this map there is a continuous chain of pleionian centers extending 

 from noi'theasteni Russia over Greenland and Labrador towai-ds Texas 

 and probably Mexico. The quasinormal line goes b;^'tween Iceland and 

 the Faroes, the departures being -|- (^°-3 in Benifjoi-d and \'estmann(> 

 and — 0°.4 C. in Thorshavn. In the latitude of Now romidland. tlu^ 

 quasinormal line must go between the continents and iiin in a southern 

 direction towards the Azores, where Angra do Heroismo l)elongs to the 

 American pleions and Ponta Delgada to the western European antipleion. 



The other maps also show, in a convincing way, that there can be no 

 question of a special Atlantic variation. Parts of the Atlantic area be- 

 long to one pleion or the other or are covered by an antipleion separating 

 pleions. 



