Ihe Mean Annual Temperature Variation. 495 



anomalies of the mean annual temperature variation, resides 

 in the fact that we have to deal with a phenomenon showing 

 intimate relationship between very far distant stations. 



On the opposite side of the world, in Baltimore*, the tem- 

 perature crests of February 22nd, March 10th, April 14th, 

 and May 10th, there observed, belong also to the curves 

 of Barnaoul and Nertchinsk. In Barnaoul they occur : 

 February 18, March 9, April 21, and Mav 10. In Nertchinsk, 

 February 22, March 12, April 20 (and May 12). 



Already Dove f noticed the fact that the anomaly occurring 

 during the month of May is noticeable in the records col- 

 lected in Arctic America and Greenland. On the other 

 hand, according to R. C. Mossman J, the cold period of May 

 is well pronounced in Argentina and Chile, north of 

 40° S. lat., and it was also observed at the winter quarters 

 of the * Discovery ? in 1902 and 1903, at Cape Adare in 

 1899, at the South Orkneys during all the years of obser- 

 vation from 1903 to 1908, with the exception of 1906. 



Mossman remarks that thus the temperature anomaly of 

 May is a bipolar phenomenon, and he adds that the curve 

 of mean atmospheric pressure at the South Orkneys, for 

 each day of the year, bears a close resemblance to that of 

 Edinburgh. 



Forcibly therefore we reach the conclusion that in a com- 

 parative study of the anomalies of the annual temperature 

 variation, Teisserene de Bort's conception of the great centres 

 of action of atmospheric circulation will rind an extensive 

 application ; because, although at present it would be pre- 

 mature to try to explain why it is that some changes of phase 

 may occur simultaneously in Arctic and Antarctic regions, or 

 in North America and Siberia, it seems impossible to conceive 

 such correlations without supposing some relationship with 

 the exchange of pressure between the seasonal and permanent 

 centres of action. 



New York City, November 2, 1916. 



* O. L. Fassig, ' The Climate and Weather of Baltimore/ pi. 3, 

 Baltimore, 1907. 

 f Loc. cit. 

 % Symon's Met. Mag. vol. xliv. p. 1 (1909). 



