246 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 70 



with variations of the air pressure difference in the sense that high 

 air pressure differences correspond to high temperatures and vice 

 versa. This is what we would have expected from this mountain 

 station. 



In the same figure is a curve (VII) for the anomahes of the air 

 temperature in Norway. Allowing for a phase displacement of some 

 months, by which interval of time the temperature variations at 

 Norway precede the air pressure difference between Colombo and 

 Hyderabad, the reader will see that the curves II and VII on the 

 whole show a certain agreement. That is, relatively high tempera- 

 tures in Norway occur somewhat before relatively great air pres- 

 sure differences in India and vice versa. 



As we said in the beginning, no better results from such a com- 

 parison of temperature with air pressure differences between two 

 fixed points was to be expected. Obviously it would be of very 

 much greater weight if the variations in the pressure difference 

 between the two action centers could be investigated, for these vary 

 their position from year to year to some extent. 



VARIATIONS OF THE NORTHEASTERLY TRADE WIND AND THE 

 SURFACE TEMPERATURE 



Liepe has emphasized the fact that variations in the strength of 

 the northeast trade winds must call forth variations in the surface 

 temperature of the stations which lie in the trade region. He thinks 

 it is sho'vvn that the increased intensity of the trade wind as a rule 

 causes a decrease of temperature and vice versa. As a measure of 

 the variations in the strength of the trade winds he uses the air 

 pressure difference between a point which lies 30° north latitude 

 and 30° west longitude and the air pressure at Sao Thiago on the 

 Cape Verde Islands. 



Taking the anomalies of air pressure difference published by 

 Liepe (1911, p. 482) we have smoothed them by taking twelve- 

 monthly consecutive means and have represented them in curve VIII 

 of figure 91 together with the curve IX for the temperature at 

 Liepe's station VI which lies in the region of this pressure difference. 

 The reader should note that this temperature curve is drawn in- 

 verted. The curve for the air pressure difference has already been 

 given in figure 56, but drawn inverted. It will be seen that for all 

 the fluctuations of the short period of years there is a very exact 

 agreement between the air pressure gradient curve and the tem- 

 perature curve for station VI and also with the temperature curves 



