NO. 4 TEMPERATURE X'ARIATIONS IN THE NORTH ATLANTIC JJ 



21 and 22. There is, however, this notable difiference that the 

 tropical yearly curves reach an absolute maximum in the year 1901 

 which exceeds that attained in the later maximum period between 

 1907 and 1909, whereas our more northerly curves, Channel to New 

 York, figure 20, 30N give their highest values in this later maxi- 

 mum period as we have already said. The curves for our more 

 southerly field between 10° and 30° west (see figs. 28 and 39A 

 and B), particularly for the most southeasterly fields, are similar 

 to the tropical curves in this respect. It appears as if in these 

 years a depression of temperature o'ccurred in the southeast, but 

 the strong minimum in the year 1904 is found in all curves alike. 



We may add that the curves for February and March for the 

 tropical field have a certain similarity with the February and March 

 curve for the 10° field 30° to 39° west longitude of the Danish obser- 

 vations between 50° and 54° north latitude. Compare for instance 

 figure 39 with figures 31 and 32. The February curves for both 

 fields show the same depression in 1904, a rise in 1905 and again 

 a depression in 1906, but there is a dissimilarity in 1907 as also in 

 1902. The March curves show the same great depression in 1903, 

 1904, 1905, a rise in 1906, depression in 1907, but a dissimilarity in 

 1908.^ All this points to a dependence and congruence in the varia- 

 tions over great stretches of the Middle Atlantic Ocean, similar to 

 those which we have already called attention to in the more eastern 

 region. This dependence is perhaps more clearly shown by compari- 

 son of the twelve-monthly consecutively smoothed temperature curves 

 for the middle stations of Petersen between 22° and 47° west longi- 

 tude, shown in figure 56, and the western Danish stations (see 

 fiS- 55)' the tropical stations of Liepe (see fig. 56), and others to 

 which we shall later refer. 



Of the three other 10° squares treated in the Dutch report only 

 the most northwesterly field between 15° and 25° west longitude, 

 shown in plate 15, field 19, contains throughout a sufficient num- 

 ber of observations to warrant the discussion of it. For this field 

 we have computed the yearly means as before, and we give both 

 curves in figure 39. Of these the full heavy curve indicates the 

 yearly mean for the 12 months, September to August, and the 

 heavy dotted curve the yearly mean for the calendar year. In this 

 figure we give for the same field also the February curve in weak 



*The February curve for the Dutch field 15° to 25° north, 35° to 45° west, 

 shows a depression in 1907 (see fig. 39) and in this year more similarity with 

 the curve of figure 32. 



