ARCT0W8KI, VHANOE.S IN DISTRIBUTION OF TEMPERATURE 89 



1901-1902. The western antipleion of 1902 is not the southeastern 

 antipleion of 1901. The consecutive maps show that the center of the 

 anti])leion remained nearly stationar}' over tlie Atlantic, east of Georgia 

 or South Carolina, and that, at the end of the year, the negative area ex- 

 tending over the States moved eastward. 



The following diagram (Fig. 33) shows the successive positions of the 

 quasinormal line for the consecutive maps of November, 1901, -October, 

 1902, until Januaiy-December, 1902. The maps show an interesting 

 feature concerning this antipleion. Its disappearance from the map was 

 preceded by a progressive shrinkage followed by an expansion. The 

 shrinkage began with April, 1901,-March, 1902, and continued until 

 June, 1901,-May, 1902, when the quasinormal line lay from Washington 

 over Louisville and Memphis towards Yicksburg; then, the negative area 



Fig. 32. — Successive positions of the 

 quasinormal line 



Fig. 33. — Proijressivc displacements of 

 the antipleion of 1901 



increased again progressively until November, 1901,-October, 1002, and 

 was followed by the eastward movement shown on the diagram. 



The consecutive maps do not give a satisfactory account of the forma- 

 tion of the negative wave which, on !he map of 1902, extends between the 

 pleions of Canada and Mexico. The regional departure maps do not 

 show the existence of the two pleionian centers of 1901 (Fig. 23) until 

 towards the end of the year. The movement of separation begins with 

 December, 1901,-November, 1902, and corresponds to the rapid drift of 

 the eastern antipleion towards the southeast. The western antipleion 

 of 1902 (Fig. 24) came from the southwest and spread out, progressively^ 

 over the entire area of the United States. 



1902-1903. Evidently the quasinormal line of the consecutive maps 

 is not the same as the quasinormal line of the departure maps from the 

 means of the decade 1900-1909, but the displacements shown and the 

 transformation of the consecutive maps must be similar to those of the 

 detailed yearly maps. I repeat this statement to avoid misunderstanding. 



