NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC 257 



shorter periods of a few years which come most prominently in the 

 fluctuations, and that these shorter periods are adapted to partially 

 cover the longer eleven-year period. Therefore it is necessary to 

 investigate first the relation between these shorter period fluctuatio'ns 

 in the air pressure difference and the corresponding shorter period 

 variations in solar activity. 



Let us now consider the consecutive twelve-monthly smoothed 

 curves which show these fluctuations most clearly. In figure 96, 

 curves II and III represent respectively the solar prominences and 

 sun spots. In both curves we have eliminated the eleven-year 

 periods by subtracting from the successive twelve-monthly means 

 the successive thirty-six monthly means. In the same figure we 

 give the corresponding curve I for the daily variations of declination 

 in Christiania in which the eleven-year period is eliminated in the 

 same way. As the reader will observe, these curves often do not run 

 parallel. 



If we now compare the sun spot curve and the prominence curve 

 with curve IV for the air pressure difference in the North Atlantic 

 and curves V and VI for the temperature in Norway and Stock- 

 holm, we find that it loo'ks in general as if the first two curves were 

 almost inverted from the last two in the time before 1897 or 1896 

 when in all the curves there were great variations present. For the 

 time after the middle of the '90's and up to 1910 it has more the 

 appearance of a direct agreement. Compare also figure 75 curve II 

 for the temperature of the water along the Norwegian coast. 



In figure 95 we give the same curve III for the sun spots and 

 also the inverted curve IV for the prominences according to the 

 Roman observations. The latter curve shows in part a very good 

 agreement with curve I for the air pressure in Stykissholm. It is 

 also worth noticing that the variations in this inverted prominence 

 curve are partly a little later than the corresponding variations in 

 the air pressure curve. With respect to the correspondences be- 

 tween these different curves, we must refer the reader more particu- 

 larly to the figures. 



We shall come later to these direct or inverted agreements be- 

 tween the terrestrial and solar shorter period fluctuations, but first 

 we will follow the shorter fluctuations from month to month which 

 are seen in curves of figure 92. Here we find something exactly 

 similar. In the curves I and II we give the monthly variations 

 in the daily number of prominences according to the observations 

 in Rome, Palermo, and Catania. As the reader will see, there 



